Frightening Fungus Among Us

  • Clinical Alert for Candida auris (C. auris) Issued by CDC
  • US Concerned About C. auris Misidentification and Drug Resistance
  • Sequencing C. auris DNA in Clinical Samples is Preferred for Identification
Strain of C. auris cultured in a petri dish at CDC. Credit Shawn Lockhart, CDC. Taken from

Strain of C. auris cultured in a petri dish at CDC. Credit Shawn Lockhart, CDC. Taken from

When I was a kid and didn’t know better, there was a supposedly funny rhyme that “there’s fungus among us.” While this saying is thankfully passé nowadays, the growing number of infections by a formerly obscure but deadly fungus is frightening. This so-called “superbug” is an antibiotic-resistant fungus called Candida auris (C. auris) that’s worth knowing about, and is the fungal focus of this blog.

First, Some Fungus Facts

Fungi are so distinct from plants and animals that they were allotted a biological ‘kingdom’ of their own in classification of life on earth, although that was only relatively recently, i.e. 1969. There are 99,000 know fungi, which exist in a wide diversity of sizes, shapes and complexity that extends from relatively simple unicellular microorganisms, such as yeasts and molds, to much more complex multicellular fungi, such as mushrooms and truffles.

It was previously thought that genomes of all fungi are derived from the genome of the model fungus Saccharomyces cerevisae, which has been used in winemaking, baking and brewing since ancient times. However, genome sequencing of more than 170 fungal species has revealed that, while the genome size of S. cerevisae is only ~12 Mb, seven species of fungus have genome sizes larger than 100 Mb. This is attributed to various evolutionary pressure-factors generating transposable elements, short sequence repeats, microsatellites, and genome duplication, and noncoding DNA.

Fungal cell walls are made up of intertwined fibers mostly comprised of long chains of chitosan, the same tough compound found in the exoskeletons of animals such as spiders, beetles and lobsters. The chitin in fungal cells is entangled with glucans and other wall components, such as proteins, forming a mass that protects the cell membrane behind it—and posing a formidable barrier against antifungal drugs.

Taken from

Taken from

In researching whether there are any nucleic acid drugs against fungi, I found one early patent by Isis (now Ionis) Pharmaceuticals for use of antisense phosphorothioate-modified oligonucleotides for the treatment of Candida infections, but virtually no other reports. I suspect that will change in the future as pathogenic fungi and other disease-causing microbes become more resistant to conventional drugs.

Fungal infections of the skin are very common and include athlete’s foot, jock itch, ringworm, and yeast infections. While these can usually be readily treated, infections caused by pathogenic fungi have reportedly risen drastically over the past few decades. Moreover, with the increase in the number of immunocompromised (burn, organ transplant, chemotherapy, HIV) patients, fungal infections have led to alarming mortality rates due to ever increasing phenomenon of multidrug resistance.

Segue to a Serious Situation

Emergence of drug-resistant fungi is, in part, the segue to the serious story of the present blog. The other part being incorrect identification of a certain fungus as being a common candida yeast, which is not only scary but seemingly inexcusable in today’s era of highly accurate PCR-based assays to accurately identify microorganisms. Here’s the situation in a nutshell.

  1. auris infection, which is associated with high mortality and is often resistant to multiple antifungal drugs, was first described in 2009 in Japan but has since been reported in countries throughout the world. Unlike many Candida infections, C auris is a hospital-acquired infection that is contracted from the environment or staff of a healthcare facility, and it can spread very quickly.

To determine whether C. auris is present in the United States and to prepare for the possibility of transmission, the Centers for Disease Control (CDC) and Prevention issued a clinical alert in June 2016 requesting that C. auris cases be reported.

(A) MALDI-TOF schematic; (B) mass spectra from three C. parapsilosis; and (C) two C. bracarensis isolates. Taken from researchgate

(A) MALDI-TOF schematic; (B) mass spectra from three C. parapsilosis; and (C) two C. bracarensis isolates. Taken from researchgate

This official alarm bell, if you will, was triggered by the following facts:

  • Many isolates are resistant to all three major classes of antifungal medications, a feature not found in other clinically relevant Candida
  • auris identification requires specialized methods such as a MALDI-TOF mass spectrometry or sequencing the 28s ribosomal DNA, as pictured below.
  • Using common methods, auris is often misidentified as other yeasts, which could lead to inappropriate treatments.

The CDC subsequently found that seven cases were identified in Illinois, Maryland, New York and New Jersey. Five of seven isolates were either misidentified initially as C. haemulonii or not identified beyond being Candida. Five of seven isolates were resistant to fluconazole; one of these isolates was resistant to amphotericin B, and another isolate was resistant to echinocandins. While no isolate was resistant to all three classes of antifungal medications, emergence of a new strain of C. auris that is would pose a serious public health issue.

Sequencing 28s ribosomal DNA. Taken from

Sequencing 28s ribosomal DNA. Taken from

Based on currently available information, the CDC concluded that these cases of C. auris were acquired in the U.S., and several findings suggest that transmission occurred:

  • First, whole-genome sequencing results demonstrate that isolates from patients admitted to the same hospital in New Jersey were nearly identical, as were isolates from patients admitted to the same Illinois hospital.
  • Second, patients were colonized with auris on their skin and other body sites weeks to months after their initial infection, which could present opportunities for contamination of the health care environment.
  • Third, auris was isolated from samples taken from multiple surfaces in one patient’s health care environment, which further suggests that spread within health care settings is possible.

A related Fox News story adds that C. auris was found on a patient’s mattress, bedside table, bed rail, chair, and windowsill. Yikes!

While the above situation in the U.S. might not seem particularly worrisome to you, the potential for emergence of more infectious C. auris strains with higher lethality should be of concern. That has already reportedly occurred in several Asian countries and South Africa. Obviously, deployment of the best available methods for pathogen identification can, in principle, lessen the likelihood of the emergence and/or spread of C. auris in the U.S. and other countries.

Case for Point-of-Care C. auris Nanopore Sequencing?

Taken from 

Taken from

Regular readers of my previous blogs know that I’m an enthusiastic fan of the Oxford Nanopore Technologies minION sequencer, which is proving to be quite useful for characterizing pathogens in very remote regions on Earth—and even on the International Space Station to diagnose astronaut infections! Notwithstanding various current limitations for minION sequencing of microbes, it seems to me that it would be relatively straightforward to generate minION data for many available samples of pathogenic fungi and genetically related microbes to assess the feasibility using minION for faster, cheaper, better unambiguous identification of C. auris minION in centralized or Point-of-Care applications.

Taken from

Taken from

If you think this suggestion is farfetched, think again, after checking out these 2016 publications using minION:

The 51.4-Mb genome sequence of Calonectria pseudonaviculata for fungal plant pathogen diagnosis was obtain using minION.

The first report of the ~54 Mb eukaryotic genome sequence of Rhizoctonia solani, an important pathogenic fungal species of maize, was derived using minION.

Sequence data is generated in ~3.5 hours, and bacteria, viruses and fungi present in the sample of marijuana are classified to subspecies and strain level in a quantitative manner, without prior knowledge of the sample composition.

CDC on C. auris Status and FAQs

In the interest of concluding this blog with the most up-to-date and authoritative information, I consulted the CDC website and found statements and replies to FAQs that are well worth reading at this link.

As a scientist, my overriding question concerns the lack of adoption of improved microbiological methods by hospitals and clinics. The above noted misidentifications of C. auris infections resulting from use of flawed lab analyses seems unacceptable. Although I don’t know all the facts or statistics to generalize, I suspect that there are other incorrect lab analyses due to use of outdated methods. On the other hand, I’m hopeful that, with the FDA’s widely touted Strategic Plan for Moving Regulatory Science into the 21st Century, the section entitled Ensure FDA Readiness to Evaluate Innovative Emerging Technologies—think nanopore sequencing—becomes actionable, sooner rather than later.

Changing established—dare I say entrenched—clinical lab tests is not simple or easy, but if it doesn’t begin it won’t happen, about which I’m quite certain. I can only wonder why development of infectious disease analytical methods and treatments seem to require a crisis. Sadly, I think it boils down to the complexities and socio-political dynamics of who pays.

Frankly, it’s my personal opinion that maybe it’s time Thomas Jefferson’s philosophy about hammering guns into plows is directed to health care.


After writing this blog, I learned that T2 Biosystems has received FDA approval to market in the U.S. the first direct blood test for detection of five yeast pathogens that cause bloodstream infections: Candida albicans and/or Candida tropicalis, Candida parapsilosis, Candida glabrata and/or Candida krusei.

Yeast bloodstream infections are a type of fungal infection that can lead to severe complications and even death if not treated rapidly. Traditional methods of detecting yeast pathogens in the bloodstream can require up to six days, and even more time to identify the specific type of yeast present. The T2Candida Panel and T2Dx Instrument (T2Candida) can identify these five common yeast pathogens from a single blood specimen within 3-5 hours.

T2Candida incorporates technologies that break the yeast cells apart, releasing the DNA for PCR amplification for detection by greatly simplified, miniaturized nuclear magnetic resonance (NMR) technology, as can be seen in this video.

In my opinion, this fascinating new technology is another example of what could be rapidly deployed toward detecting C. auris.

RNA and DNA Examples of ‘Seek, and Ye Shall Find’

  • New RNA Modification Found in the Epitranscriptomic Library for Mammals
  • Ditto for a DNA Modification in Mammalian Epigenetics
  • What Will ‘Ye’ Find Next with Improved RNA and DNA Analytical Methods?

‘Seek, and ye shall find’ is a biblical quote (Matthew 7:7) that many might say is a self-evident statement indicating that to find something you need to look for it. In any case, I used it as a segue for us scientists to remember that our collective understanding of RNA and DNA is limited, in part, by the analytical tools we use for these nucleic acid molecules. To me this predicament is akin to a person under the lamp post at night being limited to find whatever is illuminated, and miss what is not. The old cartoon below conveys a humorous variant of this. But I digress…

Taken from

Taken from

In previous postings here, I’ve commented on new illuminations—pun intended—for RNA modifications, such as pseudouridine, about which understanding of function is just emerging. And likewise for congeners of the 5-methyl group of cytidine in DNA, such as 5-hydroxymethyl or 5’-formyl moieties.

To continue this metaphor—but to get to the point—the lamp post’s light-field has been recently expanded to allow researchers to now find previously unseen modified bases in mammalian RNA and DNA, namely, N1-methyladenosine and N6-methyl-2’-deoxyadenosine, respectively. Briefly, here’s what’s been reported.

Expanding Epitranscriptomics

Just like modification of bases in DNA after its replication leads to what’s called epigenetics—which I’ll get to in the next section—modification of bases in RNA after its transcription leads to epitranscriptomics. This somewhat of a tongue-twister term was first introduced in 2013 by Sibbritt et al. in reference to increasing amounts of data for methylated bases in mRNA in the form of N6-methyladenosine (m6A) and 5-methylcytosine (m5C).

Both m6A and m5C have long been known to exist in both prokaryotic and eukaryotic organisms, but only more recently have a flurry of publications shed light—pun intended—on the precise locations, as well as enzymatic introduction and removal of m6A and m5C. This dynamic “writing” and “erasing” has been expertly reviewed by He and coworkers, who have also contributed to these discoveries.

m1A; taken from

m1A; taken from

He and collaborators at the University of Chicago, together with researchers in Israel, have recently reported in venerable Nature magazine a new mRNA modification, namely N1-methyladenosine (m1A), which occurs on thousands of different gene transcripts in eukaryotic cells spanning genetically simple yeast to much more complex mammals.

Taking advantage of newly developed sequencing approaches—i.e. brighter lamp posts in my metaphor—they showed that m1A is enriched around the start codon upstream of the first splice site. More specifically, they observed that m1A “preferentially decorates more structured regions around canonical and alternative translation initiation sites, is dynamic in response to physiological conditions, and correlates positively with protein production.”

They conclude by noting that “these unique features are highly conserved in mouse and human cells, strongly indicating a functional role for m1A in promoting translation of methylated mRNA.” So, as I said at the beginning of this blog, seek and ye shall find, and He did—capital H and pun intended.

Incidentally, those of you who are chemists will recognize that the ionic structure for m1A pictured above can undergo deprotonation to form a formally neutral counterpart having an H-N=C-N-CH3 moiety, as shown in TriLink’s catalog for the triphosphate derivative of m1A. Which one, or the proportion of these two structures for m1A exists in an mRNA of interest will depend on sequence context, local pH, etc. In this regard, scientists will need to somehow seek, in order to find, those answers in epitranscriptomics.

Expanding Epigenetics

m1A; taken from

m1A; taken from

Until recently, mammalian epigenetics had been solely focused on 5-methyl-2’-deoxycytidine and sequentially oxidized versions thereof, i.e. having hydroxyl, formyl, and carboxyl moieties, all of which are offered by TriLink as various products as either 5’-triphosphates or oligonucleotides. In less complex, prokaryotic organisms such as bacteria, N6-methyl-2’-deoxyadenosine (m6dA) is prevalent, but whether it is found in mammals has remained unclear until now.

A multi-university collaboration with the single-molecule-sequencing company Pacific Biosciences now report (Wu et al. 2016) the existence of m6dA in mouse stem cells. This landmark discovery was even more exciting because of the identification of an enzyme that removes methyl groups from m6dA, and by finding that m6dA is enriched in certain regulatory DNA sequences. Together these data provide clues to the possible function of m6dA in mammalian genomes.

Akin to my introductory light-from-the-lamp-post metaphor, detection and location of m6dA was enabled by more powerful analytical methods compared to those available in the past. Using state-of-the-art liquid chromatography-tandem mass spectrometry (LC-MS/MS), Wu et al. found that m6dA represented only 6–7 bases per million (!) adenines genome-wide. m6dA was enriched ~4-fold in genomic regions associated with a rare histone protein, H2AX, although the reasons for this association remain unclear.

The authors next determined specific locations of m6dA in sequences of DNA bound to H2AX by using Pacific Biosystems single-molecule real-time (SMRT) sequencing, which detects different kinetics with which a polymerase enzyme replicates modified bases compared with standard ones. Readers interested in this clever—dare I say “SMaRT”—method can check out my previous blog on SMRT.

In my opinion, the most challenging aspect of investigating epigenetics and epitranscriptomics is deciphering the dynamics and functional impact of “writing” and “erasing” methyl groups on bases in DNA and RNA, respectively. Erasure, i.e. removal of methyl groups is carried out by so-called demethylase enzymes. Several demethylases of the AlkB protein family have been shown to remove methyl groups from m6A in RNA as a means of regulating mRNA function. In mammals, this protein family has nine members, among which AlkBH1-deficiency was found by Wu et al. in mouse embryonic stem cells (ESCs) to lead to accumulation of m6dA in the genome, and that AlkBH1 could remove methyl groups from m6dA in DNA in vitro.

Intriguingly, Wu et al. further discovered that AlkBH1 worked most effectively on single-stranded DNA in vitro, thus raising the question of whether the enzyme preferentially operates during transcription or DNA replication in vivo, when DNA is transiently single stranded.

It’s also worth noting that enzymes that “write” (i.e. add) methyl groups to the N6-position of dA in mammalian DNA remain to be defined, as do the “reader” proteins that detect genomic m6dA.

In conclusion, I hope that this brief synopsis of new findings in “epi-marking” RNA and DNA has been illuminating—pun intended—with regard to molecular biology and the need for applying ever more powerful analytical methods to find more of what we are looking for: the molecular basis for living organisms.

On second thought, it seems to me that scientific discovery is perhaps more like moving forward from one lighted area to the next…

As usual, I welcome your comments.

New CRISPR System Reported for Targeting RNA Instead of DNA

  • Current “CRISPR Craze” for DNA Editing is Catalyzing Creativity
  • Early CRISPR Innovator Feng Zhang Now Reports Targeting RNA
  • This New “C2c2” System has Specificity Issues But is Nevertheless Promising

Just when you thought that the “CRISPR craze” would soon transition from the fundamental discovery phase to the improvements phase, something entirely new for CRISPR has come along. That something, recently published by Feng Zhang and others in venerable Science magazine, targets RNA instead of DNA. Consequently, this may lead to transient vs. permanent editing, as well as other RNA- vs. DNA-based applications.

Before further commenting on this exciting new RNA-targeting approach using CRISPR, here are a few snippets about the original DNA version of CRISPR to set the stage, and substantiate my tongue-in-cheek referral to the craze about it.


Taken from

Taken from

Editing with CRISPR, which is short-form for CRISPR-Cas9, uses sequence-specific guide RNA (gRNA) to target DNA for cutting by Cas9 nuclease, as depicted below. Guide RNA and Cas9 can be introduced into cells either encoded in a vector or as synthetic gRNA and synthetic Cas9 mRNA, which TriLink offers in either wild-type or base-modified forms of Cas9 mRNA. CRISPR for genome editing was publicly described in Science in 2012 by co-corresponding authors Jennifer A. Doudna, a biologist at the University of California, Berkeley, and the French microbiologist Emmanuelle Charpentier. But Feng Zhang, at the Broad Institute, was first to obtain a patent on the technique.

Not surprisingly, given the financial potential for DNA editing by CRISPR, which has been called the ‘biotech discovery of the century,’ there is ownership litigation. This dispute is getting rather ugly, if you will, according to an article in Science titled Accusations of errors and deception fly in CRISPR patent fight.

crispPotential financial gain aside, PubMed stats I found clearly substantiate the craze factor in numeric terms: >4,000 publications to date with a rapidly increasing trajectory, i.e. ~600 in 2014 and ~1,200 in 2015, which is an average of roughly 4 publications every day in that year!

By the way, in the chart above that I made for CRISPR publications in PubMed, there was only one report in 2002, which was the first publication to identify CRISPR. These Dutch investigators used computer analysis to find a novel family of repetitive DNA sequences that is present among both domains of the prokaryotes (Archaea and Bacteria), but absent from eukaryotes or viruses. They noted that “[t]his family is characterized by direct repeats, varying in size from 21 to 37 bp, interspaced by similarly sized non-repetitive sequences. To appreciate their characteristic structure, we will refer to this family as the clustered regularly interspaced short palindromic repeats (CRISPR).” 

Taken from

Taken from

CRISPR was also selected as 2015 Science Breakthrough of the Year, and is featured in an interesting YouTube video that is definitely worth watching, in my opinion.

Enough said for CRISPR editing of DNA, let’s move on to RNA editing with CRISPR that offers a fundamentally different editing approach: whereas DNA editing makes permanent changes to the genome of a cell, CRISPR-based RNA-targeting approach may allow researchers to make temporary changes. Moreover, this can be adjusted up or down, and may one day provide greater specificity and functionality than existing methods for RNA interference (RNAi) using either siRNA or antisense oligos.

CRISPR Targeting RNA

Feng Zhang. Taken from

Feng Zhang. Taken from

At the risk of seeming to be too trendy, this section heading could have read “Feng Zhang 2.0” in that Zhang at the Broad Institute, along with co-corresponding author Eugene V. Koonin at NIH and uber-famous “Broadster” Eric Langer plus others on a large team, have characterized a new CRISPR system that targets RNA—but not DNA. In their recent Science publication they demonstrated that this new system involves a Class 2 type VI-A CRISPR-Cas effector—aptly abbreviated C2c2 (pronounced “see too, see too”)—that has RNA-guided RNase function.

The researchers originally identified C2c2 in the bacterium Leptotrichia shahii (L. shahii) in a systematic search for previously unidentified CRISPR systems within diverse bacterial genomes. They focused on C2c2 because its sequence contained two copies of a domain called higher eukaryotes and prokaryotes nucleotide-binding (HEPN) that has only been found in RNases. Mutating the putative catalytic site within either of C2c2’s HEPN domains demonstrated that none of the mutated enzyme versions could cut RNA in vitro, suggesting that both HEPN domains are necessary for C2c2 to work.

CRISPR-C2c2 from L. shahii reconstituted in E. coli to mediate interference of the RNA phage MS2 via crRNA facilitated by the two HEPN nuclease domains. Taken from Abudayyeh et al.

CRISPR-C2c2 from L. shahii reconstituted in E. coli to mediate interference of the RNA phage MS2 via crRNA facilitated by the two HEPN nuclease domains. Taken from Abudayyeh et al.

But C2c2 Cleaves Collateral RNA—a Case for “Lemons into Lemonade”?

Unlike Cas9, which cuts DNA only within the sequence dictated by the CRISPR gRNA, C2c2 was found to make cuts within the target sequence and adjacent, nonspecific sequences. While this collateral cleavage obviously presents a specificity problem, Zhang and his colleagues were able to create a deactivated C2c2 (dC2c2) variant by alanine substitution of any of the four predicted HEPN domain catalytic residues. To me this clever trick is like converting “lemons into lemonade” in that undesired non-specific cleavage is transformed into a programmable RNA-binding protein having potential utility.

For example, the investigators speculate that the ability of dC2c2 to bind to specified sequences could be used in the following ways:

  • Bring effector modules to specific transcripts in order to modulate their function or translation, which could be used for large-scale screening, construction of synthetic regulatory circuits, and other purposes.
  • Fluorescently tag specific RNAs in order to visualize their trafficking and/or localization.
  • Alter RNA localization through domains with affinity for specific subcellular compartments.
  • Capture specific transcripts through direct pull-down of dC2c2 in order to enrich for proximal molecular partners including RNAs and proteins.

Listen to Zhang’s Grad Students 

While the details of this seminal work published in Science is not easily summarized, its practical implications have been concisely translated, if you will, by first coauthor Omar O. Abudayyeh, and second coauthor Jonathan S. Gootenberg—both graduate student members of the Zhang lab—in three short videos that I encourage you to watch at this link.

Left: Omar Abudayyeh. Taken from Right: Jonathan Gootenberg Taken from

Left: Omar Abudayyeh. Taken from Right: Jonathan Gootenberg Taken from

Publication protocol generally lists coauthors in order of contribution, so in this C2c2 publication that has many coauthors, these fellows know what they’re talking about because they did lots of the lab work. Congrats to them, Feng Zhang (again), and all of the other contributors.

As always, your comments are welcomed and encouraged.

Jerry’s Favs from the Recent OTS Meeting

  • 12th Annual OTS Meeting in Montreal Très Excitant!
  • RNAi Approach to Treating Preeclampsia Spurred by Researchers’ Personal Experiences
  • Ionis Video for Spinal Muscular Atrophy Amazes the Audience
  • 30 years later, PS-Modified Oligonucleotides Continue to be Enabling!

City line of Montreal. Taken from

The 12th Annual Meeting of the Oligonucleotide Therapeutics Society (OTS) held on September 25-28, 2016 in French-speaking Montreal, Quebec, Canada brought together hundreds of enthusiastic investigators from around the world. All attendees share a common interest in oligo-based therapeutics, and we gratefully say merci beaucoup to the organizers of this very well run event.

Commenting here on my “favs” is limited by space, and highly subjective—by intent—focusing on only several impressions that struck me as worth sharing. Readers interested in perusing all of the lecture titles and speaker biosketches can do so at this link, which also lists corporate sponsors—including TriLink—and connects with the regularly updated OTS website.

Jerry’s balcony view of OTS 2016 presentations at the Centre Mont-Royal venue

Jerry’s balcony view of OTS 2016 presentations at the Centre Mont-Royal venue

Before getting to my selected topics, I wish to congratulate the OTS Board of Directors and Scientific Advisory Council for their ongoing valuable contributions to this society, and continuing efforts to include participation by the new generation of young investigators, who I’m sure will collectively make exciting advances in the field of oligonucleotide therapeutics. It was pleasure for me to me meet some of these “next gen” scientists, and learn about their current work, which is quite sophisticated by comparison to what I and others did in the early—dare I say primitive—era of antisense oligonucleotide drug discovery.

Toward Treating Preeclampsia: Personalized Drug Developers’ Stories

Preeclampsia (PE) is a disorder that occurs during pregnancy, affects both the mother and the fetus, and is characterized by elevated blood pressure, swelling and protein in the urine. According to a Preeclampsia Foundation fact sheet, every minute somewhere in the world a woman dies in pregnancy or childbirth, which amounts to more than 500,000 deaths each year. In addition, PE causes ~15% of premature births in industrialized countries and is the number one reason doctors decide to deliver a baby early.

Dr. Melissa J. Moore is a professor in the RNA Therapeutics Institute and the Department of Biochemistry and Molecular Pharmacology at the University of Massachusetts Medical School. Taken from

Dr. Melissa J. Moore is a professor in the RNA Therapeutics Institute and the Department of Biochemistry and Molecular Pharmacology at the University of Massachusetts Medical School. Taken from

In her OTS lecture on clinical development of an RNA interference (RNAi) approach to treat PE, Dr. Melissa J. Moore (pictured below) introduced an attention-grabbing personal element when she revealed her bout with PE. Coincidentally, she discovered that her then attending physician, Dr. S. Ananth Karumanchi, had begun his quest for identifying PE-causality at the molecular level prompted by his daughter’s dangerously premature birth due to PE. This turned out to be a truncated kinase receptor abbreviated sFlt1, which Moore described as Karumanchi’s break-through discovery for possible development of PE therapeutics.

The condensed version of these two remarkably interwoven, PE-related personal stories—that you can hear first-hand from Moore on YouTube—was an agreement between Moore and Karumanchi to collaborate on discovering whether double-stranded short-interfering RNA (siRNA) targeting sFlt1 could be useful as an RNAi-based PE therapeutic agent.

Melissa Moore’s ultrasound sonogram. Taken from her YouTube video

Melissa Moore’s ultrasound sonogram. Taken from her YouTube video

Moore went on to gratefully acknowledge her colleague at the RNA Therapeutics Institute, Prof. Anastasia Khvorova, for setting up “by hook or by crook” the first non-profit academic facility for large-scale production of siRNA suitable for clinical development. This led to designing and producing a nuclease-resistant siRNA comprised of 2’-OMe/2’-F ribonuceosides and phosphorothioates at the ends, with an attached hydrophobic cholesterol moiety for improved delivery.

Even more impressive—at least to me—was Moore’s ability to access pregnant baboons in a non-human primate model of PE. This is inherently difficult due to issues involving non-human primates for any research, and is technically much more challenging compared to, for example, infectious disease models. Dr. Moore showed lots of compelling results from her model studies, and concluded her talk by saying that clinical studies were planned.

In closing this section, it’s worth noting that Moderna—a leading mRNA therapeutics company—has recently announced its appointment of Dr. Moore as Chief Scientific Officer of Moderna’s mRNA Research Platform.

Ionis Pharmaceuticals Drug Video for Spinal Muscular Atrophy Amazes the Audience

Dr. Stanley T. Crooke. Taken from

Dr. Stanley T. Crooke. Taken from

This year’s OTS Lifetime Achievement Award address by Dr. Stanley T. Crooke, founder and CEO of Ionis Phamaceuticals (formerly Isis Pharmaceuticals), was presented to an auditorium packed with attendees who, like me, greatly admire Crooke’s many scientific and commercial contributions to the field over the past decades. These currently include more than 450 (!) scientific publications and 38 drugs in the pipeline, with 3 finishing Phase III—very impressive and promising indeed!

Ionis’ impact on providing efficacious oligonucleotide-based therapies to patients was conveyed most powerfully—in my opinion—by a video about Cameron, an infant SMA patient who was born with Spinal Muscular Atrophy (SMA). According to an NIH fact sheet, SMA is a genetic disease that causes weakness and wasting of the voluntary muscles in the arms and legs of infants and children. These disorders are linked to an abnormal or missing gene known as the survival motor neuron gene 1 (SMN1), without which motor neurons in the spinal cord degenerate and die.

As detailed elsewhere by Chiriboga et al., Nusinersen (aka ISIS-SMNRx or ISIS 396443) is a 2’-O-(2-methoxyethyl) (MOE) phosphorothioate-modified antisense oligonucleotide (ASO) designed to alter splicing of SMN2 mRNA and increase the amount of functional SMN protein produced, thus compensating for the genetic defect in the SMN1 gene. The cartoon shown below depicts how this ASO targets an hnRNP-A1/A2–dependent splicing silencer in intron 7 of the SMN pre-mRNA. Nusinersen displaces hnRNP proteins from this silencer site on the SMN2 pre-mRNA, facilitating accurate splicing of SMN2 transcripts (e.g., increasing the synthesis of transcripts containing exon 7) and resulting in increased production of full-length SMN protein.

Taken from after Chiriboga et al.

Taken from after Chiriboga et al.

Ionis and its commercial partner Biogen announced in August 2016 that Nusinersen met the primary endpoint pre-specified for the interim analysis of ENDEAR, the Phase 3 trial evaluating Nusinersen in infantile-onset (Type 1) SMA. The analysis found that infants receiving Nusinersen experienced a statistically significant improvement in the achievement of motor milestones compared to those who did not receive treatment. In September, Biogen announced that it applied for Priority Review by the FDA that, if granted, would shorten the review period of Nusinersen following the Agency’s acceptance of the NDA filing by Ionis and Biogen.

Cameron at 2+ years enjoying the moment with his mom. Taken from YouTube

Cameron at 2+ years enjoying the moment with his mom. Taken from YouTube

The amazing effect of Nusinersen warranting this Priority Review is best appreciated—in my opinion—by watching a YouTube video showing the progress of Cameron during his treatment. When viewing this video, keep in mind that Cameron’s Type I SMA is typically evident at birth or within the first few months, and that symptoms include floppy limbs and trunk, feeble movements of the arms and legs, swallowing and feeding difficulties, and impaired breathing. Sadly, the prognosis is poor for babies with SMA Type I. Most die within the first two years. But not so for Cameron, shown below at 2+ years, thanks to Nusinersen!

Phosphorothioate-Modified Oligonucleotides Continue to be Enabling—30 Years On!


Left: Prof. Fritz Eckstein. Taken from Right: Prof. Wojciech J. Stec. Taken from

That nuclease-resistant phosphorothioate (PS)-modified internucleotide linkages have had an enabling influence on all manner of oligo-based drug development is evident from the first-ever OTS Lifetime Achievement Award in 2015 being given to Prof. Fritz Eckstein for his pioneering and life-long work on PS linkages in DNA and RNA. Following Fritz’s lead, and aided by the availability of ABI’s DNA synthesizer, Prof. Wojciech J. Stec and yours truly published the first completely automated method for synthesis of fully or partially PS-modified DNA oligos in 1984. This opened the door for early antisense experiments with PS-modified oligos, which have continued now for 30 years!

Perhaps surprisingly, the ever evolving field of oligonucleotide therapeutics continues to rely on PS-modifications in a myriad of mechanistically distinct strategies, such as “classic” antisense to mRNA, siRNA, anti-miRNAs, modulators of RNA splicing, etc. In this regard, Dr. Crooke’s concluding remarks on his goal of deciphering the “code” for protein binding to chemically modified ASO, led me to muse about the negatively charged P-Smoiety in such binding of PS-containing ASO.

Taken from

Taken from

My initial thought was that P-S likely enhances binding to positively charged amino acid moieties in proteins, due to greater polarizability vs. P-O, and that Sp or Rp P-Sstereochemistry may likely influence binding. Moreover, this spatial aspect of a binding “code” can now be studied using stereospecific synthesis of PS-ASO by either Stec’s OTP method or Wada’s oxazaphospholidine method. Time will tell—stay tuned!
As usual, your comments here are welcomed.

Chinese Scientists to Pioneer First Human CRISPR Clinical Trial

  • Chinese Team Begins First CRISPR-Based Anticancer Immunotherapy Clinical Study
  • US Consortium’s CRISPR Clinical Study OK’d by NIH Panel
  • Survey Indicates More Worry than Enthusiasm for Gene-Editing in Babies
Taken from

Taken from

Regular readers of my blog will recall a number of previous postings on gene editing using CRISPR-Cas9 (aka CRISPR), which has rapidly become the hottest trend in nucleic acid-based biotechnology and medical research. That opinion is partly based on the fact that this relatively new technology has already amassed thousands of publications, including 1,250 in 2015 alone! Additional evidence follows from the numerous start-up and established biopharma companies pursuing CRISPR-based therapeutics, which is “the biggest biotech discovery of the century” according to one report.

Now, even more exciting developments for CRISPR are on the horizon. Chinese researchers are poised for the first human clinical trial using CRISPR, and an analogous study in the US awaiting FDA approval. Both of these trials involve forms of cancer immunotherapy, which is a very hot field in itself, and is briefly introduced in the next section.

Cancer Immunotherapy

Cancer immunotherapy is the use of the immune system to treat cancer either actively, passively, or by a combination of these approaches, which exploit the fact that cancer cells often have macromolecules on their surface that can be detected by the immune system (aka tumor-associated antigens, TAAs). Active immunotherapy directs the immune system to attack tumor cells by targeting TAAs, whereas passive immunotherapies enhance existing anti-tumor responses and include the use of monoclonal antibodies, lymphocytes and cytokines.

Numerous antibody therapies have been approved by the FDA and other regulatory authorities worldwide. In contrast, active immunotherapies, which usually involve the removal of immune cells from the blood or from a tumor for reintroduction to the patient, have lagged in such approvals. In fact, the only US-approved cell-based therapy is Dendreon’s Provenge®, for the treatment of prostate cancer. A recent series of NY Times articles highlights some powerful examples of cancer immunotherapy, especially from the perspective of interviews with patients and their physicians.

Taken from

Taken from

For the purpose of this blog, I’ll add that adoptive T-cell therapy is a form of passive immunization by the transfusion of T-cells, which are found in blood and tissue and usually activate when they find “foreign” pathogens. These pathogens can be either infected cells, or antigen presenting cells present in tumor tissue, where they are known as tumor infiltrating lymphocytes. Although these cells can attack the tumor, the environment within the tumor is highly immunosuppressive, preventing immune-mediated tumor death.

As depicted below, T-cells specific to a tumor antigen can be removed from a tumor sample or filtered from blood. Subsequent activation and culturing is performed ex vivo, with the resultant cells being reinfused. Importantly, activation can take place through genetic engineering, such as gene editing by CRISPR.

Cancer specific T-cells can be obtained by fragmentation and isolation of tumor infiltrating lymphocytes, or by genetically engineering cells from peripheral blood. The cells are activated and grown prior to transfusion into the recipient (tumor bearer). Taken from

Cancer specific T-cells can be obtained by fragmentation and isolation of tumor infiltrating lymphocytes, or by genetically engineering cells from peripheral blood. The cells are activated and grown prior to transfusion into the recipient (tumor bearer). Taken from

CRISPR Goes Clinical in China

As I write this post, Chinese scientists at Sichuan University’s West China Hospital in Chengdu will reportedly become the first in the world to inject people with cells modified using the CRISPR gene-editing method. This landmark trial will involve patients with metastatic non-small cell lung cancer who have not responded to chemotherapy, radiation therapy and/or other treatments.

The team will extract T cells from the blood of the trial participants and then use CRISPR to knock out a gene encoding a protein called PD-1 that normally regulates the T cell’s immune response to prevent it from attacking healthy cells. As depicted below, this so-called checkpoint has been targeted by small molecule inhibitors (anti PD-1), but with somewhat limited success so far—notably including failure of a would-be billion-dollar drug (Opdivo®) recently reported by Bristol-Myers Squibb. Nevertheless, the presently envisaged PD-1 gene-edited cells will be amplified in the lab and re-introduced into the patient’s bloodstream to circulate and, hopefully, attack the cancer.

Taken from

Taken from

Potential Concerns of CRISPR Clinical Trials

While the Chinese trial may be groundbreaking, it is not without risk. There is concern that the edited T-cells could attack normal tissue as it’s well documented that CRISPR can result in gene edits at the wrong place in the genome. To help mediate this risk, the T-cells will be validated by biotechnology company MedGenCell—a collaborator on the trial—to ensure that the correct gene is knocked out before the cells are re-introduced into patients.  Since the primary purpose of this phase one trial is to determine if the approach is safe, participants will be closely monitored for side effects, and researchers will pay close attention to biological markers in the blood.

Some may say that this type of trial in humans is premature, but China has always tried to be a leader in CRISPR research. Carl June, a clinical researcher in immunotherapy at the University of Pennsylvania in Philadelphia explains, ‘China places a high priority on biomedical research.’ And Tetsuya Ishii, a bioethicist in Japan, is quoted in Nature magazine as saying that ‘When it comes to gene editing, China goes first.”

Initial CRISPR Clinical Trial in USA Awaiting Review Board and FDA Approvals

While the Chinese team seems positioned to be the first to conduct a CRISPR clinical trial, the US isn’t far behind. As reported earlier this summer, the Recombinant DNA Research Advisory Committee (RAC) at the NIH has approved an analogous—but genetically more complex—proposal to use CRISPR-edited T cells for cancer immunotherapy. The RAC reviews all proposals for human trials involving modified DNA that are conducted in the United States, and the investigators now have to convince review boards at their own institutions, and the FDA, to allow the trial. This will hopefully be done by the end of 2016.

The proposed trial is a collaborative effort involving the University of Pennsylvania, M.D. Anderson Cancer Center in Texas, and the University of California, San Francisco. This trial will be funded by a $250-million immunotherapy foundation formed in April 2016 by former Facebook president Sean Parker. According to a news item in Nature, The University of Pennsylvania will produce the edited cells, and will recruit and treat patients alongside the collaborating medical centers in Texas and California.

In this study, researchers will perform three CRISPR edits with T cells from patients with several types of cancers: 1. a gene for a protein engineered to detect and target cancer cells will be inserted, 2. a natural T-cell protein that could interfere with this process will be removed and 3. the gene for a protein that identifies the T cells as immune cells and prevents the cancer cells from disabling them will be removed. The researchers will then infuse the edited cells back into the patient.

Both of the studies being performed by the Chinese and US teams are very exciting to me. I will be paying close attention to the progress of these studies over the next few months and hope to report back to you with some very interesting and ground breaking results.

Survey Indicates Public Concern in the US About Gene Editing in Babies

A Pew Research Center pole focusing on concerns about gene editing was recently reported in Nature. The poll surveyed more than 4,700 people in the United States and the results indicate that more people are concerned than enthusiastic about gene editing.

The quadrants below (from 0-100%) show responses to the question, “How worried or enthusiastic do you feel about gene editing to reduce disease risk in babies?”

Taken from

Taken from

While these findings speak for themselves, I hasten to add that this same pole also asked “Have you heard or read about this topic?” The following replies (in quadrants from 0-100%) indicate that a substantial percentage of respondents who have not at all read about gene editing nevertheless expressed either worry or enthusiasm for gene editing. Ditto for those who read a little about gene editing.


It would seem, then, that we should take this poll with a grain (or two) of salt as it apparently includes a substantial amount of uninformed opinion. This is not too surprising given the complex nature of gene editing and it’s relatively new position in research. We can see from the results of this poll that a significant amount of education may be needed to garner increased public support for gene editing. Hopefully, the results of the studies highlighted above will begin to pave this road.

Hope for the Best but Expect Complications

This section heading, which summarizes my parting comments about the advent of CRISPR-enabled clinical trials, is based upon my having participated in several decades of research on nucleic acid-based concepts for radically different approaches to traditional small-molecule therapeutics. First was the idea of using chemically modified antisense oligonucleotides to block gene expression, which encountered non-specificity issues, low potency, delivery, and a host of other issues that took two decades to sort through. Then there was the idea of using chemically modified short-interfering RNA (siRNA) for modulating gene expression via RNA interference (RNAi). This, too, encountered similar problems in reaching the clinic. Ditto for anti-microRNAs (antagomirs).

I’m hoping that CRISPR-based therapies meet with success far faster—and prove to be affordable to society. I won’t, however, be surprised if progress is slow—and quite expensive.

Are you excited about potential CRISPR-based therapies? Do you have concerns about their safety and efficacy? Do you believe the general public is ready to accept gene editing therapies? Please share your thoughts as your comments are always welcome.

Update on Zika Virus Detection by RT-PCR

  • Various RT-PCR Assays for Zika Virus Have now Received Emergency Use Authorization (EUA) from the FDA
  • Quest Diagnostics’ Assay Approved by FDA for General Use as a Zika Test
  • Troubled Theranos Touts New “miniLab” for Zika EUA
  • Vaccine Development Progressing Albeit Relatively Slowly
Aedes aegypti mosquito. Taken from

Aedes aegypti mosquito. Taken from

In January 2016, I posted a blog about the then emerging public awareness of Zika virus (ZIKV), which is spread by the bite of infected mosquitos—primarily the Aedes aegypti mosquito. Sadly, ZIKV can be passed from a ZIKV-infected pregnant woman to her fetus leading to development of a brain defect (microcephaly) and/or other malformities. Moreover, ZIKV is now associated with sexual transmission and blood transfusion. This is scary news.

This update was prompted by the additional fact that ZIKV is on the rise and there is still no vaccine, according to the Centers for Disease Control and Prevention (CDC)—my “go to” source for loads of authoritative information about this infectious disease. Weekly updated ZIKV-infection “case counts” in US States and US Territories were given as ~1,200 and ~6,500, respectively on Aug 10th, and increasing to ~3,400 and ~20,000 on Sep 21st —only 6 weeks later!

As I pointed out in my previous blog on ZIKV, absent an anti-ZIKV vaccine, there is considerable interest in mosquito abatement as well as early detection, notably by reverse-transcription PCR (RT-PCR) of this RNA Flavivirus. Now that Zika infection by mosquitos in Florida has been found, leading to several CDC warnings, I thought it would be both apropos and technically interesting to provide the following update on ZIKV structure and RT-PCR.

ZIKV Genome and Structure

As of last month, my PubMed search of “Zika [Title/Abstract] AND RT-PCR [Anywhere]” gave 55 publications. Incidentally, there are now a number of Zika genome sequencing publications, such as this lead reference. It’s worth noting that ZIKV genome sequencing enables monitoring the potential evolution of new genomic variants that might foil existing RT-PCR assays and guide the selection of new primers for RT-PCR.

ZIKV genome. Taken from with permission from SIB Swiss Institute of Bioinformatics, ViralZone

ZIKV genome. Taken from with permission from SIB Swiss Institute of Bioinformatics, ViralZone

It’s also worth pointing out that Zika’s overall molecular capsid structure is enveloped, spherical, and has a diameter of ~40 nm in diameter, as depicted below in schematic form, and pictured in the accompanying electron microscopic image. The surface proteins are arranged in an icosahedral-like symmetry.

ZIKV capsid structure. Taken from with permission from SIB Swiss Institute of Bioinformatics, ViralZone

ZIKV capsid structure. Taken from with permission from SIB Swiss Institute of Bioinformatics, ViralZone

This is a transmission electron micrograph (TEM) of ZIKV, which is a member of the family Flaviviridae. Virus particles are ~40 nm in diameter, with an outer envelope, and an inner dense core (see above). The arrow identifies a single virus particle. Taken from

This is a transmission electron micrograph (TEM) of ZIKV, which is a member of the family Flaviviridae. Virus particles are ~40 nm in diameter, with an outer envelope, and an inner dense core (see above). The arrow identifies a single virus particle. Taken from


In the interest of giving explicit credit to various investigative groups who have developed RT-PCR assays for ZIKV, here are links and short snippets I’ve selected from publications, in chronological order, found in the aforementioned PubMed search. Interested readers are encouraged to check out the original publication for details.

The first report of an RT-PCR assay for ZIKV appears to be by Faye et al. in 2008 at the Institut Pasteur de Dakar in Senegal, who targeted the envelope protein coding region and tested ZIKV isolates previously collected over a 40-year period from various African countries and hosts. The assay’s detection limit and repeatability were respectively 7.7pfu/reaction and 100% in serum; none of 19 other Flaviviruses tested were detected. Faye et al. in 2013 extended this work to include quantitative RT-PCR detection of ZIKV and evaluation with samples from field-caught mosquitoes.

Kinetics of ZIKV detection in urine compared to serum from 6 patients was described by Gourinat et al. in 2015 at the Institut Pasteur, Noumea, New Caledonia using RT-PCR primers and probes previously reported by others. Urine samples were positive for ZIKV more than 10 days after onset of disease, which was a notably longer period than 2-3 days for serum samples. These researchers concluded that urine samples are useful for diagnosis of ZIKV infections, and are preferred to serum wherein virus titer diminishes more rapidly.

Musso et al. in 2015 working in Tahiti, French Polynesia with 1,067 samples collected from 855 patients presenting symptoms of Zika fever found that analysis of saliva samples increased the rate of detection of ZIKV at the acute phase of the disease compared to serum samples. They noted that saliva was of particular interest when blood was difficult to collect, especially for children and neonates.

Most recently, Xu et al. in 2016 in China reported the development of a SYBR Green (intercalator dye)-based qRT-PCR assay for detection of ZIKV. Although their results indicate that the assay is specific, it’s important to note that SYBR-type detection can be subject to nonspecific artifacts, for which TriLink’s proprietary CleanAmp™ Primers can be investigated to potentially ameliorate such problems, as discussed in this downloadable pdf publication by TriLink researchers.

ZIKV In Vitro Diagnostic Assays

As detailed elsewhere, the Secretary of Health and Human Services (HHS) earlier this year determined that “there is a significant potential for a public health emergency that has a significant potential to affect national security or the health and security of United States citizens living abroad and that involves Zika virus.” The Secretary of HHS further declared that “circumstances exist justifying the authorization of the emergency use of in vitro diagnostics for detection of Zika virus…”.

The following RNA-based assays and suppliers are currently listed by the FDA for this Emergency Use Authorization (EUA):

  • xMAP® MultiFLEX™ Zika RNA Assay (Luminex Corporation)
  • VERSANT® Zika RNA 1.0 Assay (kPCR) Kit (Siemens Healthcare Diagnostics Inc.)
  • Zika Virus Real-time RT-PCR Test (Viracor-IBT Laboratories, Inc.)
  • Aptima® Zika Virus Assay (Hologic, Inc.)
  • RealStar® Zika Virus RT-PCR Kit U.S. (Altona Diagnostics)
  • Zika Virus RNA Qualitative Real-Time RT-PCR (Focus Diagnostics)
  • Trioplex Real-time RT-PCR Assay (CDC)

Among these, two are particularly notable—in my opinion. Trioplex Real-time RT-PCR Assay is a multiplexed laboratory test developed by the CDC to simultaneously detect ZIKA, dengue virus, and chikungunya virus RNA, each of which can be transmitted primarily by Aedes aegypti mosquitos to cause infections with similar symptoms. Consequently, it is useful to have a single test that can detect each of these viruses in the same sample. Full details for the Trioplex assay are provided in a 40-page downloadable pdf from the CDC at this link.

In brief, this CDC-developed test uses virus-specific primer pairs and fluorogenic hydrolysis probes each differentially dual-labeled with fluorescent reporter and quencher dyes for in vitro detection of complementary DNA (cDNA). The detection follows reverse-transcription of RNA isolated from clinical specimens including serum, cerebral spinal fluid, urine, and amniotic fluid. It’s worth pointing out that I subsequently found a publication in 2016 by several collaborating academic groups regarding an analogous triplex RT-PCR assay for the same three viruses.

The other notable assay is Zika Virus RNA Qualitative Real-Time RT-PCR developed by Focus Diagnostics, which in April 2016 was the first of the aforementioned ZIKV tests to receive authorization by the FDA for use by qualified labs to detect ZIKV RNA in blood samples of those meeting CDC clinical criteria or of people who may have lived in or traveled to an affected location or had other exposure to the virus. Quest Diagnostics, the parent company of Focus Diagnostics, announced it would make the test broadly available to physicians, including those in Puerto Rico in May 2016.

ZIKV EUA Sought by Theranos for Its new “miniLab”

Theranos, which has been in the news regarding troubles over its stealthy proprietary system for finger-stick blood tests, appears to be pivoting its strategic plans. It announced at the August 2016 American Association of Clinical Chemistry Meeting its R&D for a new, fully automated miniLab system, including analytical and method comparison results of its ZIKV nucleic acid-amplification-based assay.

According to its press release, the company collected finger-stick samples from subjects, including people in the ZIKV-infested Dominican Republic, and shipped those to Palo Alto, California to run on the miniLab. Although I was unable to obtain these particular results, I did find the following figure at the TechCrunch website showing functional components of the miniLab along with an article by Sarah Buhr that’s worth a quick read, in my opinion.

Taken from

Taken from

According to the aforementioned Theranos press release, the company has submitted assay validation data for this Zika assay to the FDA for an EUA. The company also states that it is unaware of any currently available capillary (i.e. finger-stick) test for ZIKV.

I’ll stay tuned for future general information about the miniLab, as well as information specifically related to ZIKV. If I hear of anything, I’ll add as a comment here or in a new post with technical details about its nucleic acid assays.

ZIKV Vaccine Status

I hope this blog has convinced you that RT-PCR of ZIKV has provided improved molecular diagnostics. I’m guessing, that like me, you find it unfortunate that there isn’t a proven anti-ZIKA vaccine as of yet. This is especially frustrating given the fact that Zika disease has been known for more than 50 years, and that it is evidently on the rise globally, including in the USA according to regularly updated CDC statistics.

In February 2016, the Obama administration requested $1.9 billion in funding for the NIH to develop a ZIKV vaccine. The US Congress continues to be deadlocked by partisan politics despite the fact that Florida state and local officials are scrambling to contain the ZIKV outbreak in Miami Beach. This outbreak poses a serious threat to the health of residents, as well to visitors who drive the region’s $24 billion-a-year tourism industry.

Nevertheless, some progress has been reported for US studies in monkeys, and US-based Inovio says it’s received FDA approval to begin studies in humans. Outside the US, Sanofi Pasteur in France is said to be poised for initiating its trials in humans, and French biotech company Valneva is reported to have succeeded in generating a ‘highly purified inactivated vaccine candidate’ using the same technical approach it used for its encephalitis vaccine that is marketed in the United States and Europe.

Lagging—dare I say “glacially slow”—action against ZIKV by the World Health Organization is quite disappointing to me, and is reminiscent of what I’ve commented on in an earlier blog concerning this bureaucracy’s ineffective response to the Ebola virus. If I had my druthers, TriLink’s previously announced engagement by Battelle in development of Ebola mRNA vaccine would somehow materialize for a Zika mRNA vaccine. In this regard, GlaxoSmithKline is reported to be preparing research studies alongside the NIH’s Vaccine Research Center to test a self-amplifying mRNA vaccine technology for Zika. Interested readers can check out this link to a fascinating PNAS publication by Geall et al. on biosynthetic self-amplifying mRNA vaccines delivered in lipid nanoparticles.

As always, your comments are welcomed.


Taken from Fleming et al. (2016) ACS Infectious Diseases

Taken from Fleming et al. (2016) ACS Infectious Diseases

One of my previous posts featured recent elucidation of biologically functional G-quadraplexes in living cells. Consequently, it’s apropos to mention here that Fleming et al. at the University of Utah have just now published the first analysis of potential G-quadruplex sequences (PQS) in the RNA genome of ZIKV. As depicted in this artistic cartoon, several PQS were found, with the most stable located near the end of the 3’ untranslated region (3′-UTR). Importantly, these investigators propose a rationale for screening G-quadruplex-binding compounds as a completely new class of anti-ZIKV drug candidates. In my opinion, this is a great example of how basic biochemical research can lead to new strategies for much needed antiviral drugs.

RNA World Revisited

  • Scripps Researchers ‘Evolve’ an RNA-Amplifying RNA Polymerase 
  • It’s Used for First Ever All-RNA Amplification Called “riboPCR”
  • TriLink Reagent Plays a Role in this Remarkably Selective in Vitro Evolution Method 
Prof. Gerald Joyce & Dr. David Horning. Photo by Madeline McCurry-Schmidt. Taken from

Prof. Gerald Joyce & Dr. David Horning. Photo by Madeline McCurry-Schmidt. Taken from

Those of you who regularly read my blog will recall an earlier posting on “the RNA World,” which was envisioned by Prof. Walter Gilbert in the 1980s as a prebiotic place billions of years ago when life began without DNA. That post recommended reading more about this intriguing hypothesis by consulting a lengthy review by Prof. Gerald Joyce. Now, Prof. Joyce and postdoc David Horning have advanced the hypothesis one step further by reporting the first ever amplification of RNA by an in vitro-selected RNA polymerase, thus providing significant supportive evidence for the RNA World. Following are their key findings, which were enabled in part by a TriLink reagent—read on to find out which one and how!

In Vitro Evolution of an RNA Polymerase

Horning & Joyce designed an in vitro selection method to chemically “evolve” an RNA polymerase capable of copying a relatively long RNA template with relatively high fidelity. The double emphasis on “relatively” takes into account that the RNA World would have many millions of years to evolve functionally better RNA polymerases capable of copying increasingly longer RNA templates with increasingly higher fidelity.

As depicted below, they started with a synthetic, highly structured ribozyme (black) wherein random mutations were introduced throughout the molecule at a frequency of 10% per nucleotide position to generate a population of 1014 (100,000,000,000,000) distinct variants to initiate the in vitro evolution process. Step 1 involved 5’-5’ click-mediated 1,2,3-trazole (Ø) attachment of an 11-nt RNA primer (magenta) partially complementary to a synthetic 41-nt RNA template (brown) encoding an aptamer that binds guanosine triphosphate (GTP). In Steps 2 and 3, the primer hybridizes to template and is extended by polymerization of A, G, C and U triphosphates (cyan).

Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

GTP aptamer showing red and cyan sequences corresponding to above cartoon. Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

GTP aptamer showing red and cyan sequences corresponding to above cartoon. Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

Step 4 involves binding of aptameric structures to immobilized GTP (green), then photocleavage of the 1,2,3-triazole linkage in Step 5, followed by reverse transcription to cDNA and conventional PCR in Step 6 for transcription into ribozymes in Step 7. Twenty-four rounds of this evolution by selection were carried out, progressively increasing the stringency by increasing the length of RNA to be synthesized by decreasing the time allowed for polymerization. By the 24th round, the population could readily complete the GTP aptamer shown below. Subsequent cloning, sequencing and screening were then used to characterize the most active polymerase, which was designated “24-3.”

The TriLink “Connection”

2'-Azido-dUTP (aka 2'-azido-UTP)

2′-Azido-dUTP (aka 2′-azido-UTP)

The aforementioned in vitro evolution process actually involves tons of experimental details that interested readers will need to consult in the published paper, which is accompanied by an extensive Supporting Information section. In the latter, a subsection titled Primer Extension Reaction describes 3’ biotinylation of the template RNA strand (brown in above scheme) using TriLink “2’-azido-UTP” (more properly named 2’-azido-dUTP) and yeast poly(A) polymerase, followed by click connection of the RNA template’s 3’-terminal 2’-azido moiety to biotin-alkyne. This very clever functionalization of the RNA template strand allowed for subsequent capture of the double-stranded primer extension reaction products on streptavidin-coated beads, followed by elution of the desired nonbiotinylated strand for GTP aptamer selection (Step 4 above).

Properties of RNA Polymerase 24-3

Needless to say—but I will—enzymologists and RNA aficionados will undoubtedly be interested in musing over the kinetic and fidelity properties of RNA polymerase 24-3.

The rate of 24-3 polymerase catalyzed addition to a template-bound primer was measured using an 11-nt template that is cited extensively in the literature to evaluate various ribozymes. It was found that the average rate of primer extension by 24-3 is 1.2 nt/min, which is ∼100-fold faster than that of the starting ribozyme polymerase randomly mutagenized for in vitro selection.

The NTP incorporation fidelities of the starting and 24-3 ribozyme polymerases on this 11-nt test template, at comparable yields of product, are 96.6% and 92.0%, respectively. Horning & Joyce noted that the higher error rate of 24-3 is due primarily to an increased tendency for G•U wobble pairing.

Phenylalanyl tRNA. Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

Phenylalanyl tRNA. Taken from Horning & Joyce, Proc. Natl. Acad. Sci., 2016

Other longer RNA templates having various base compositions or intramolecular structures were also studied, with the stated “final test of polymerase generality” being use of 24-3 to synthesize yeast phenylalanyl tRNA from a 15-nt primer (in red right). The authors humorously describe the results as follows:

“Despite the stable and complex structure of the template, full-length tRNA was obtained in 0.07% yield after 72 h. This RNA product is close to the limit of what can be achieved with the polymerase, but is likely the first time a tRNA molecule has been synthesized by a ribozyme since the end of the RNA world, nearly four billion years ago.”

Exponential Amplification of RNA

PCR is the most widely used method for amplifying nucleic acids, and involves repeated cycles of heat denaturation and primer extension. The 24-3 RNA polymerase was used to carry out PCR-like amplification, but in an all-RNA system (named riboPCR by Horning & Joyce) using A, G, C, and U triphosphates and a 24-nt RNA template composed of two 10-nt primer-binding sites flanking the sequence AGAG. Somewhat special conditions were employed:

  • The concentration of Mg2+ was reduced to minimize spontaneous RNA cleavage
  • PEG8000 was used as a “molecular crowding” agent to improve ribozyme activity at the reduced Mg2+ concentration
  • Tetrapropylammonium chloride was added to lower the melting temperature of the duplex RNA

Under these conditions, 1 nM of the 24-nt RNA template was driven through >40 repeated thermal cycles, resulting in 98 nM newly synthesized template and 106 nM of its complement, corresponding to 100-fold amplification. Sequencing of the amplified products revealed that the central AGAG sequence was largely preserved, albeit with a propensity to mutate the third position from A to G, reflecting the low barrier to wobble pairing.

Amplification of a 20-nt template (without the central insert) was monitored in real time, using FRET from fluorescently labeled primers, and input template concentrations ranging from 10 nM to 1 pM. The resulting amplification profiles shown in the paper are typical for real-time PCR, shifted by a constant number of cycles per log-change in starting template concentration. A plot of cycle-to-threshold vs. logarithm of template concentration, also shown in the paper, was linear across the entire range of dilutions indicating exponential amplification of the template RNA with a per-cycle amplification efficiency of 1.3-fold.

Implications for the Ancient RNA World

It would be an injustice to Horning & Joyce if I would try to paraphrase their concluding discussion of this investigation, so here is what they say:

The vestiges of the late RNA world appear to be shared by all extant life on Earth, most notably in the catalytic center of the ribosome, but most features of RNA-based life likely were lost in the Archaean era. Whatever forms of RNA life existed, they must have had the ability to replicate genetic information and express it as functional molecules. The 24-3 polymerase is the first known ribozyme that is able to amplify RNA and to synthesize complex functional RNAs. To achieve fully autonomous RNA replication, these two activities must be combined and further improved to provide a polymerase ribozyme that can replicate itself and other ribozymes of similar complexity. Such a system could, under appropriate conditions, be capable of self-sustained Darwinian evolution and would constitute a synthetic form of RNA life.

Applications for Today’s World of Biotechnology

The aforementioned report by Horning & Joyce has received wide acclaim in the scientific press and world-wide public media as supporting the existence of a prebiotic RNA World, billions of years ago, from which life on Earth evolved.

While the academic part of my brain, if you will, fully appreciates the significance of these new insights on “living” RNA eons ago, the technical applications part of my brain is more piqued by possible practical uses of all-RNA copying or all-RNA riboPCR.

I, for one, plan to muse over possible applications of such all-RNA systems in today’s world of biotechnology, and hope that you do too, and are willing to share any ideas as comments here.

Spartan Cube—The World’s Smallest Molecular Diagnostic Device

  • Records Are Meant to be Broken—Including Those for PCR Diagnostics
  • Spartan Bioscience Claims It’s Cube is World’s Smallest Mol Dx Device 
  • The Cube was Launched at the Recent AACC Clinical Lab Expo 


[22]-annulene. Taken from

[22]-annulene. Taken from

In the spirit of the recent Olympic games, and as the saying goes—records are meant to be broken. When I was in grammar school, a big buzz in sports was who would be the first to break the 4-minute mile; answer: Roger Bannister in 3 minutes and 59.4 seconds in 1954—now 17 sec faster. In my college craze days, it was how many persons can fit into a Volkswagen Beetle; answer: I couldn’t find the first feat, but the current record is 20 crammed into an old style Beetle in 2010. Then during my graduate organic chemistry studies, there was interest in synthesizing increasingly larger annulenes—completely conjugated CnHn monocyclic hydrocarbons akin to benzene (n=6); answer: [22]-annulene with n=22 (see below) synthesized by F. Sondheimer. But I digress…

Our collective fascination with records—and beating them—also applies to all sorts of instruments for health-related sciences, such as the most powerful MRI imaging systems (currently from GE) or longest-DNA-sequencing system (currently from PacBio). Due to the seemingly endless utility of PCR, there is a continual stream of claims for the fastest PCR system (currently from BJS Biotechnologies) or—more to point herein—smallest PCR system.

To wit, regular readers of my blog will recall an April 2016 post titled World’s Smallest Real-Time PCR Device, which referred to a hand-held system reported by Ahrberg et al. for real-time, quantitative PCR (qPCR). That system is pictured below next to the original system commercialized by ABI in the 1990s that weighed 350 pounds and was 7 feet long!

Left: World’s smallest real-time PCR device. (Taken from Ahrberg et al). Right: Applied Biosystems 7700 real-time PCR system. (Taken from

Left: World’s smallest real-time PCR device. (Taken from Ahrberg et al). Right: Applied Biosystems 7700 real-time PCR system. (Taken from

It seems that PCR records fall as easily as those in the Olympics. Not even a year later, Ahrberg’s claim is being challenged by Canadian company Spartan Bioscience, which recently introduced its Cube device at the 2016 AACC Annual Scientific Meeting & Clinical Lab Expo. Following are some technical details that I thought were worth sharing.

Taken from

Taken from

Cube Facts

Given its amazingly small size of only 4 x 4 x 4 inches, there apparently has been some remarkable engineering achievements to be able to squeeze-in what’s needed for the rapid heating and cooling required for PCR thermal cycling. Ditto for the optics required to enable fluorescence detection. Like other relatively small devices intended for emerging Point-of-Care (POC) applications in a doctor’s office or clinic, there is wireless connectivity to a laptop that serves as the user interface for operation and data analysis, as well as a power source for the Cube via a USB cable.

You’re likely wondering by now how much the Cube will sell for. Unfortunately, I was not able to obtain a list price from Spartan’s CEO at this time, so we’ll all have to wait and see.  I’ll post the answer as a comment to this blog as soon as I find out the price.

Inside the Cube—Perhaps 

I actually don’t know exactly what’s inside the Cube, but some possibilities of what might be are as follows. I’ve based these educated guesses on a Spartan Bioscience patent (US pat. no. 8,945,880) by Paul Lem and others entitled Thermal cycling by positioning relative to fixed-temperature heat source. As depicted below, a hot block provides a heat source at a fixed temperature to thermally cycle PCR reaction vessels that can be precisely moved by a micrometer to and from the hot block in a repeated manner.

Taken from US patent no. 8,945,880

Taken from US patent no. 8,945,880

As for how fluorescence might be measured to monitor each PCR reaction in real-time, one possibility is depicted below. Basically, each reaction tube is proximate to excitation light from an LED, and has a slit at the bottom for emitted light that is collected and processed into a typical real-time PCR curve.

Taken from US patent no. 8,945,880

Taken from US patent no. 8,945,880

Before the Cube

Prior to launching the Cube, Spartan Bioscience has been selling an FDA-Cleared in vitro diagnostic product called Spartan RX, which is also relatively compact, and carries out fully automated—“cheek swab-to-result”—PCR analysis of certain Cytochrome P450 2C19 (CYP2C19) genotypes. Roughly 1-in-3 people carry CYP2C19 mutations that can impair metabolism of a wide variety of commonly used drugs. Consequently, these PCR-based results are a valuable aid to clinicians in determining strategies for therapeutics that are metabolized by the Cytochrome P450 2C19.

I was favorably impressed by the fact that this CYP2C19 assay qualifies for reimbursement from Medicare and most insurers, according to the company’s website, which adds that there is an ongoing 6,000-patient clinical trial entitled Tailored Antiplatelet Initiation to Lessen Outcomes due to Clopidogrel Resistance after Percutaneous Coronary Interventions (TAILOR PCI).

The Spartan RX cheek swab POC results have been recently compared to centralized genotyping with a TaqMan® allelic discrimination assay (Life Technologies) using qPCR and with the GenID® reverse dot-blot hybridization assay (Autoimmun Diagnostika GmbH). Published results indicate excellent agreement, and led to the following conclusions by the authors: “Compared to both laboratory-based genotyping assays, the POC assay is accurate and reliable, provides rapid results, can process single samples, is portable and more operator-friendly, however the tests are more expensive.”

I look forward to finding out more about the Cube and the PCR results it can obtain. I’ll post more information on my blog as it becomes available. As usual, your comments are welcomed.


To me, there’s something visually intriguing about a cube, perhaps because it’s one of the so-called Platonic Solids, which have been known since antiquity and studied extensively by the ancient Greeks.

Taken from

Taken from

Platonic solids such as the cube have also fascinated chemists, as evidenced by there being a substantial amount of published literature on the synthesis and physical properties of platonic solids. For example, cubane (C8H8) is a synthetic hydrocarbon molecule that consists of eight carbon atoms arranged at the corners of a cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane was first synthesized in 1964 by Philip Eaton and Thomas Cole. Prior to this work, researchers believed that cubic carbon-based molecules would be too unstable to exist.

Taken from

Taken from

On the fun side, the cube was morphed—so to speak—into what became an amazingly popular game, or should I say, object of competition. Rubik’s Cube is a 3-D combination puzzle invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. If you’re wondering about the world’s record for solving this puzzle, it’s currently a mind-boggling 4.9 sec, according to a list (with video links) of this and past records that appear to have been broken regularly, just as I opined at the beginning of this blog. But I digress…yet again.

Virtual Reality for Graphene Nanopores and Space Station Sequencing 

  • Simulated Sequencing Takes Virtual Reality Way Beyond Games  
  • In Silico Simulations Suggest Possible 99.99% Accuracy for Graphene Nanopores 
  • minION Nanopore Sequencer is Sent to the International Space Station



Taken from

This blog is mostly about an international team of researchers who are using Virtual Reality (VR)—in the form of computational modeling—to simulate a new approach to DNA sequencing using nanopores made out of graphene. While VR is a hot trend in all sorts of so-called immersion media, such as those offered by Oculus (that was acquired by Facebook for $2 billion in 2014), computation-based VR has been used by scientists for simulating molecular interactions for a relatively long time. However, extending molecular simulations to complex (aka many-atom) systems like nanopores and DNA has had to wait for bigger, faster, cheaper computing.

In this blog, I’ll also discuss the recent launch of a commercially available nanopore sequencer for the first ever DNA sequencing in space using a self-landing rocket operated by Space X (co-founded by uber-famous multi-billionaire entrepreneur Elon Musk). It’s hard for me to even imagine what seemingly incongruent mix of topics could be more intriguing than these. As the now trendy saying goes, you can’t make this stuff up. But I digress…

Lift off! Taken from                     Self-landing! Taken from indianexpress .com

Lift off! Taken from    –  Self-landing! Taken from

Nanopore Sequencing 

baseFrom an earlier blog you’ll know that I’m a huge fan of tiny nanopores for sequencing, which is a 20+ year old concept, as depicted below from a seminal patent wherein DNA was envisaged as moving through a pore-in-lipid bilayer leading to base-dependent transient blockage of ionic current from which sequence is determined.

Taken from

Taken from

After two decades, this prophetic concept of nanopore sequencing has recently been realized, and commercialized by Oxford Nanopore Technologies (ONT) using “bionanopore” technology. Comparing the images above and below, you’ll see that bionanopores are, in many respects, quite similar to the first described nanopores, wherein a pore-forming protein, α-hemolysin (gray), is embedded in a lipid bilayer (blue). On the other hand, there is an attached DNA-processive enzyme, 29 DNA polymerase (brown), that feeds in the single strand of DNA for sequencing; details may be found elsewhere.

An alternative strategy for nanopore sequencing is to replace this type of bionanopore (composed of biological macromolecules) with a pore constructed of non-biological materials, notably silicon-based semiconductors that enable electrical signal generation and data processing. This would-be evolution of nanopore sequencing from biological constructs to various types of solid-state materials can be read about elsewhere.

Whither Goest Graphene?

It seems the next step in the progression of nanopore technology is those made of graphene—the trivial name for a very special form of carbon that was long known but exceedingly difficult to make. In fact, the process is so difficult that Andre Geim and Kostya Novoselov at The University of Manchester were awarded the 2010 Nobel Prize in Physics for their work enabling the production and characterization of graphene.

Geim and Novoselov. Taken from 

Geim and Novoselov. Taken from

Graphene is a two-dimensional array or “sheet” of carbon atoms that is usually depicted by the ball-and-stick model (pictured at the left below) as a one-atom-thick sheet of otherwise infinite dimensions. Since nothing is infinite in the real world, sheets of graphene have edges to which hydrogen is bonded, but for simplicity is ignored. This carbon-carbon bonding with carbon-hydrogen edges is akin to that in polycyclic aromatic hydrocarbons familiar to readers who are chemists.

Taken from  

Taken from

Taken from Bayley (2010) in

Taken from Bayley (2010) in

Because of graphene’s unique electrical properties and single-atom-thin structure, the basic idea is that a nanometer-size hole in graphene might be made—somehow—to allow DNA and ions to pass through and thus generate electrical signals—somehow—that are accurately deciphered—somehow—into DNA sequence. Oh, and let’s not forget that this sequence information must differentiate—somehow—3’->5’ from 5’->3’ directional pass through. All these “somehows” are meant to indicate that it’s far easier to imagine the concept of graphene nanopore sequencing, as fancifully shown below, than to actually do it.

Taken from Mechant et al. Nano Letters (2010)

Taken from Mechant et al. Nano Letters (2010)

The most daunting practical problem deals with how to “drill” tiny holes in graphene. One approach has been to use controlled electron-beam exposure in a transmission electron microscope. Initial demonstration of this approach was published in 2010 by Merchant et al. in Nano Letters in a paper titled DNA Translocation through Graphene Nanopores, from which the schematic left is taken.

In this device, a few-atoms-layer piece of graphene (1-5 nm thick) having an ~10 nm hole is suspended over a 1 μm diameter hole in a 40 nm thick silicon nitride (SiN) membrane suspended over an ~50 × 50 μm2 aperture in a silicon chip coated with a 5 μm silicon oxide (SiO2) layer in such a way that a bias voltage (VB) is applied between the reservoirs to drive DNA through the nanopore. Although DNA could be detected, the graphene pore size was too big to allow sequence detection.

Taken from Chang et al. Nano Letters (2010)

Taken from Chang et al. Nano Letters (2010)

Similar studies by Schneider et al. were also reported in Nano Letters in 2010, which appears to be a watershed year for this journal inasmuch as another noteworthy nano-detection scheme for DNA was described therein by Chang et al.—but with an important new feature. Namely, using gold electrodes (in yellow, below) separated by only 2 nm and conjugated to dC, a derivative of dG (blue balls) apparently was able to H-bond (magenta) to dC—based on dC-dG complementarity and detected as electron tunneling signals. This transient, base pair-specific H-bonding is what has now been further investigated by others albeit in the following form of Virtual Reality.

Virtual Reality Nanopore Sequencing

In contrast to the above “real” experiments, others have simulated reality using mathematical calculations based on theoretical chemistry, which is Virtual Reality that has physical significance well beyond simply playing games. Mathematical modeling or computation simulations are phrases generally used to describe these so-called in silico “experiments” that serve as indications of what could be done, in theory, if this Virtual Reality is actually translatable to the real world. But I digress…

An international team of investigators in the U.S., Germany, and Netherlands has recently reported studies titled Nucleobase-functionalized graphene nanoribbons for accurate high-speed DNA sequencing. Although this article is a dreaded “pay-to-read” article, there is a brief news piece about it at the website for the U.S. National Institute of Standards and Technology (NIST) where some of this work was conducted.

Taken from

Taken from

As is evident from the schematic shown below, these investigators borrowed from the aforementioned types of publications to imagine a graphene nanopore having its internal edges functionalized with nucleobase moieties that could potentially H-bond with DNA bases in a sequence specific manner—à la Chang et al. Under appropriate conditions, this could provide the basis for sequencing via measurement of induced current fluctuations.

More specifically, they imagined a sheet (aka ribbon) of graphene 4.5 x 5.5 nm with several nucleobase moieties attached to a 2.5 nm nanopore. In animated simulations (which are linked at the NIST website), you can watch how this sensing device would perform at room temperature in water with attached cytosine H-bonding to detect G in DNA.

When you watch this simulation, you’ll immediately notice how “wiggly” DNA is due to random motions of its constituent groups and atoms. You’ll also see detection of each translocating (i.e. passing G) as an increasing signal being recorded in real-time. While time as a parameter in this simulation is real, the simulation itself is not real, but rather virtual reality based on state-of-the art theoretical calculations by a computer.

With that caveat in mind, the performance was said to be 90% accurate (due to missed bases rather than wrongly detecting a base) at a rate of 66 million bases per seconds, which to me is mindboggling ultra-fast. Moreover, if this device could be fabricated as four sequentially-located graphene pores each functionalized with either C, G, A, or T, the researchers estimate that “proofreading” would increase accuracy to 99.99%, as required for sequencing the human genome.

Virtual reality is, well, not reality. And sometimes dreams and reality go in opposite directions. However, if indeed the above imaginary device and simulations were to become reality—nanopore sequencing would indeed be advanced dramatically from today’s performance.

ONT’s minION Sequencer in Space

In transitioning back to reality, it’s almost unbelievable to me that ONT’s minION nanopore sequencer—which I’ve blogged about before—was sent to the International Space Station (ISS) in April 2016 to carry out the first ever sequencing of DNA in space. If that wasn’t enough “buzz”, then the fact that this was achieved by uber-famous Elon Musk’s Space X company made it way more so, along with much ado in successfully landing the rocket’s first-stage on a relatively tiny platform in the ocean. This is all amazing stuff.  And to think that not so long ago, we were thinking how great it would be if self-landing rockets were really possible, not just a fun concept in video games and sci-fi movies!  Maybe virtual reality isn’t that far from becoming reality, but I digress….

The first aim of putting the minION nanopore into space is to demonstrate the feasibility of nanopore sequencing in microgravity. That being done would then allow use of the minION to rapidly sequence astronaut samples in the ISS to diagnose, for example, an infectious disease or other health issue.

Interested readers can peruse elsewhere much more about this historic milestone, as well as watch and listen to a short (but very exciting) video titled Space Station Live: Big DNA Science in a Small Package. The video was posted on Twitter on July 21st and features the minION device (aka The Biomolecular Sequencer).

NASA minION flight hardware for the ISS experiments packaged for shipment to the ISS. Credit: NASA/Sarah Castro. Taken from

NASA minION flight hardware for the ISS experiments packaged for shipment to the ISS. Credit: NASA/Sarah Castro. Taken from

I look forward to learning the results of the minIONs research in space. I hope that it’s “mission accomplished!” and of great use in years to come. BTW, if you’re a “space buff” like me, you can watch and listen to ISS-Mission Control live streaming 24-7 at this website.

As usual, your thoughts about this blog are welcomed as comments.

DIY CRISPR Kit – Door to Democratization or Disaster?

  • Gene Editing with CRISPR is All the “Buzz”
  • Low-Cost CRISPR Kit Being Sold to DIY “Biohackers”
  • What is the Balance Between Democratization and Preventing Disaster?

The dictionary definition of democratization is the transition to a more democratic political regime. Since democracy emphasizes the role of individuals in society, democratization is generally perceived to be good. This political concept of democratization is being increasingly morphed, if you will, to describe the transition of science and technology from trained specialists in traditional labs to any individual, anywhere—including someone’s kitchen table.

Taken from

Taken from

Lest you get the impression I’m an elitist, and not in favor of fostering better understanding—and appreciation—of science by non-scientists everywhere, I definitely am not. I want the value of science to be widely appreciated. Even if I weren’t of that opinion, democratization of science and technology is already evident in this exemplary cartoon indicating how DNA is now familiar to virtually everyone. But I digress…

Taken from


It is evident that molecular biology has also undergone democratization based on emergence of so-called “do it yourself” (DIY) advocates of biology (DIY-BIO), which on the surface seems like a good thing. But, as I’ll expand upon below, DIY-BIO has morphed in a way which has elevated concerns that a well-intentioned DIY aficionado anywhere can now access genetically powerful CRISPR reagents that might inadvertently unleash a harmful home-made organism.


First off, I should note that gene editing by CRISPR—thankfully short for “clustered regularly-interspaced short palindromic repeats”—actually involves another component named Cas9—short for CRISPR associated protein 9. Cas9 is an enzyme that recognizes single guide RNA (sgRNA) hybridized to one strand of specifically targeted DNA via the 5’end of sgRNA, as depicted in green in the mechanism below. The remaining sgRNA has a double-stranded “stem” (black, red) and loop (purple) internal structure, and a 3’ end with several stem-loop structures (red).

Taken from

Taken from

The scissors indicate Cas9 cutting both strands of DNA, which thus allows for insertion of so-called donor DNA and, consequently, enabling a variety of genetic manipulations in plants, bacteria, human or animal cells. Chemically synthesized sgRNA that target any gene of interest can be readily designed for purchase, along with Cas9 in the form of biosynthetic Cas9 mRNA encoding this necessary protein component.

CRISPR’s importance as an emerging, useful tool for gene editing is evident from the number of publications in PubMed that have approximately doubled each year since the seminal to give an estimated 2,500 publications indexed to CRISPR as a search term. Unfortunately (but perhaps not surprisingly given the billion-dollar implications), there is an ongoing dispute over inventorship involving the Broad Institute (see Feng Zhang patent), the University of California, and the University of Vienna.

Biohacker Promotes DIY CRISPR Kit

Josiah Zayner (Taken from

Josiah Zayner (Taken from

As mentioned in the introduction, self-proclaimed “biohackers” who are avid fans and practitioners of DIY molecular biology, have been busily “doing their thing” for some time now without much cautionary publicity. That’s changing, however, as a result of the advent of CRISPR together with relatively easy access to its sgRNA and Cas9 reagents. One case in point involves Josiah Zayner, who has a PhD from the Department of Biochemistry and Molecular Biophysics at the University of Chicago and now lives in the San Francisco Bay Area.

Zayner’s online biographical sketch states that he is “very active in Biohacking and DIY Science and run[s] an online Biohacking supply store The ODIN.” By visiting the website for The ODIN, which reportedly raised $65,000 by crowdfunding online via Indiegogo, you’ll find various items for conducting molecular biology experiments, along with an “about” page stating that “smaller groups of people, small labs or even DIY Scientists on their own can do amazing things if they have access to resources that are normally only available to large heavily funded labs and companies.”

While this seems all fine and good is some ways, the item offered by The ODIN that has led to controversy is the first-ever DIY kit for CRISPR. This, according to an article in The Mercury News, “raises the specter—deeply troubling to some experts—of a day when dangerous gene editing is conducted far from the eyes of government regulators, posing risk to the environment or human health”.

The article goes on to quote one expert who said The ODIN kit is sold for manipulating yeast and could never be used to alter human genes, while another expert cautioned that the kit can teach basic principles to do so with appropriate modifications. Another problem is inadvertent conversion of yeast into a harmful microorganism that might be accidentally spread.

Taken from

Taken from

While I share these concerns, it will be virtually impossible to prevent individuals or small groups intent on nefarious activities using CRISPR technology. On the other hand, I have to admit that I would be very concerned if I were living next door or otherwise nearby Josiah if he is indeed practicing what he’s preaching, so to speak, using CRISPR in his kitchen as pictured right.

CRISPRized Plants, Too

If you think that DIY is a passing fad with few devotees, think again. Aside from the main DIY-BIO website that you can peruse, a recent online article in Fusion talks about a couple of DIY enthusiasts doing things that make the hairs on my neck stand up, as the saying goes. For instance, David Ishee, a 30-year-old Mississippi resident who never attended college, does at-home experiments in his shed using online kits for growing plants, but will now use CRISPR to carry out gene editing.

Ishee reportedly will use software like DeskGen that advertises its “on-demand CRISPR libraries” for gene editing, and is quoted as saying “That gives me a lot of new options. Up until now, all the genetic edits I’ve made have been limited to plasmids and unguided genomic insertions. That limits the kinds of cells I can work with and the types of work I can do.”

So what will Ishee do? The answer is that nobody but he knows. If his genetically edited plants grow and seeds get carried by the wind, they could someday end up in your backyard. What then? Who knows? Could be creepy.

Possibly harmful, irreversible consequences of completely democratized CRISPR are completely unknown. Therein lies the essence of the problem that has many experts quite concerned, as reported in Fusion. I share that concern.

Parting Shot

In closing this brief story about DIY synthetic biology using CRISPR, I must say that I wish journalists writing for newspapers and other media would stick to news that is factual and not interpreted for commentary that is flat out wrong or intentionally provocative. My case in point is the following big font, bold letters headline:

“Finally, your chance to play God!”

This was used by to recycle the aforementioned piece by The Mercury News. Shame on for this misleading and totally wrong exclamation. But I digress…

I would greatly appreciate knowing your thoughts about DIY CRISPR by sharing them here as comments.