Antimicrobial resistance (AMR) threatens the effective prevention and treatment of an ever-increasing range of infections. It’s a leading mortality factor worldwide, but the newly discovered antibiotic, clovibactin, may offer a pivotal solution. It effectively kills drug-resistant bacterial pathogens without detectable resistance—even multidrug-resistant “superbugs.”
Continue reading “Clovibactin: A Revolutionary Antibiotic with No Resistance”Each year, the International Symposium for Human Identification (ISHI) covers a variety of the latest topics in DNA forensics through sessions, workshops and poster presentations. While last year’s meeting largely focused on using investigative genetic genealogy (IGG) and developments in DNA databases, another topic that garnered widespread interest was current efforts being taken to mobilize DNA analysis labs.
One of the speakers, Sylvain Hubac, PhD, Head of the DNA Division of the Forensic Science Laboratory of the French Gendarmerie, helped create a mobile DNA lab solution back in 2015. This innovative mobile lab, designed and patented by the French Armed Forces for the French Gendarmerie (IRCGN), has been used to facilitate DNA identification in a number of emergency settings since it’s inception. From identifying the remains of the Germanwings Flight 9525 plane crash victims in 2015 and the victims of the 2016 Bastille Day terrorist attack in Nice, to adapting the lab to aid in sample processing during the COVID-19 pandemic, the mobile lab has played an especially instrumental role in Disaster Victim Identification (DVI) scenarios.
However, the mobile lab was more recently employed in a new DVI context: identifying victims of the conflict in Ukraine. On the last day of ISHI 33, Dr. Hubac presented on the unique challenges posed when identifying victims of war, and the tools, protocols and system that made the mobile lab uniquely suited for this purpose.
Continue reading “How an Innovative Mobile DNA Analysis Lab Helped Identify War Victims in Ukraine”Mitogen-activated protein kinases (MAPKs) are a large family of proteins that regulate diverse cellular functions in eukaryotes, including gene expression, proliferation, differentiation and apoptosis (1). MAPK signaling pathways typically include three sequentially activated kinases, and these pathways are triggered in response to extracellular stimuli, such as cytokines, mitogens, growth factors and oxidative stress (1). Ultimately, the signal is transmitted to the nucleus, with the activation of a specific transcription factor that modulates the expression of one or more genes.
Among MAPK pathways, the RAS-RAF-MEK-ERK signaling pathway has been studied extensively. Mutations in RAS family proteins and resultant dysregulation of the signaling pathway are implicated in a variety of cancers. Therefore, this pathway is a popular target for anticancer drug development.
Marine seagrasses are submerged flowering plants that form essential underwater meadows, fostering diverse ecosystems and providing a habitat for marine life. Our first Promega qPCR Grant winner and marine ecologist, Dr. Agustín Moreira-Saporiti, plans to continue adding to a fascinating body of work aimed at understanding flowering in marine seagrasses.
Dr. Moreira-Saporiti began his journey into marine plant ecology at the University of Vigo, Spain, where he earned a bachelor’s degree in marine sciences. He then went on to complete a master’s degree at the University of Bremen (Germany) where his thesis focused the ecology of seagrasses in Zanzibar, Tanzania. His passion for marine botany led him down a deeper exploration of marine plants, unraveling the intricate web of ecosystem processes within seagrasses.
If you could, would you enter a suspended metabolic state for the chance to reawaken 46,000 years from now, as you are today? For one nematode discovered in Siberian permafrost, the answer is a resounding “yes”. A study published in late July of this year details recent research that expands on a paper published in 2018 wherein scientists announced that they successfully reanimated a small but resilient nematode, or roundworm, who remained alive for tens of thousands of years in a state called cryptobiosis after being frozen in extreme Arctic soil conditions.
Loss of life and serious illness from contamination of manufactured products that are consumed as food or used in medical procedures illustrate the need to prevent contamination events rather than merely detect them after the fact. High-profile news stories have described contamination events in compounding pharmacies (1), food processing and packaging plants (2) and medical device manufacturers (3). Although contamination in manufacturing settings can be physical, chemical, or biological, this article will focus environmental monitoring to determine the quality of a manufacturing facility with respect to microbial contamination.
To ensure that the products they produce and package are manufactured in a high-quality, contaminant-free environment, many industries are required to establish routine environmental monitoring programs. Samples are collected from all potential sources of contamination in the production environment including air, surfaces, water supplies and people. Routine monitoring is essential to detect trends such as increases in potential pathogens over time or the appearance of new species that have not been seen before so that contamination events can be prevented.
Because environmental monitoring requires identification to the level of the species, most environmental monitoring programs will collect samples and then send them off to a facility to be sequenced for genomic identification of any microbial species. Such genotypic analysis involves DNA sequencing of ribosomal RNA (rRNA) genes to determine the taxonomic classification of bacteria and fungi. In this method, informative sections of the rRNA genes are amplified by PCR; the PCR products sequenced; the sequence is compared to reference libraries; and the results interpreted to make a species-level identification for a given microbial isolate.
Continue reading “On-site, In-house Environmental Monitoring to Obtain Species-Level Microbial Identification”The human microbiome, the bustling cooperative of all the microscopic creatures that naturally colonize in and on our bodies, wields a surprising amount of influence over many of the unseen processes that are critical to our overall health and wellness. Over the course of decades, we have learned that this is particularly true for the microbes that reside in our gastrointestinal tract, collectively known as our gut microbiota.
Our gut microbiota is constantly communicating with our bodies, though our relationship with our gut can feel like trying to have a conversation with someone who only speaks a language we do not know or understand—you can take an educated guess at what they are saying based on their expressions and gestures, but the true message and meaning behind their actions is not always discernable. So while we can feel that someone in our gut is unhappy when we have a tummy ache, the true mechanism behind exactly who is unhappy and why, is not as obviously deduced or understood.
What if there was a tool that could help us more easily interpret the language of our microbiota, giving us the means to both better understand our microbiomes as well as to detect biomarkers of various diseases? Recent studies have shown that such a solution may be (quite literally) right under our noses: our breath.
Mosquitos are the deadliest animal on earth—not because of the itchy bites they leave behind, but because of the diseases those bites can spread. Of these diseases, malaria, is the most widespread, killing 619,000 people in 2021 (1). Almost half of the world’s population live at risk of malaria (2). In humans, malaria is caused by certain species of single-cell micro-organisms belonging to the genus Plasmodium (3), which are transmitted by anopheline mosquitos.
Controlling malaria has proven challenging. Vaccines have yielded incomplete protection, and insecticides that once were successful at control mosquito populations are becoming less effective as the insects develop resistance. Finally, Plasmodium parasites themselves have developed resistance to leading anti-malaria drugs (2).
Approaches that target the disease-causing Plasmodium organisms—inside the mosquito and before they are transmitted to humans—could provide as effective way forward. In the past, researchers have explored leveraging genetically modified bacterium to kill or inhibit Plasmodium development within their mosquito host. However, using genetically altered bacteria makes wide-spread adoption of these techniques problematic. A recent study published in Science describes the discovery and early investigative results using a naturally occurring bacterial strain that inhibits Plasmodium spread (2). The bacteria, Delftia tsuruhatensis TC1, was isolated from a mosquito population that unexpectedly became resistant to Plasmodium infection (2).
Once the bacterium was identified as the cause of Plasmodium inhibition, the researchers tested how easily the bacteria was to introduce into naïve mosquitos and how effective it was at disrupting infection. To do this, they colonized female mosquitos by feeding them a sugar and bacterium solution and then Plasmodium-infected blood. Bacterial colonization occurred in almost all the mosquitos offered the sugar and bacterium food. Initially, bacterial colonization numbers were low, but they increased 100-fold following the blood meal.
Investigation into how D. tsuruhatensis inhibits Plasmodium infection showed that it inhibits oocyte formation within the gut, and this inhibition lasts for at least 16 days. Specifically, the inhibition is the result of a secreted compound called harmane, which is a small hydrophobic methylated b-carboline (2). When harmane is secreted in the guts of mosquitos it inhibits Plasmodium parasite development. The researchers further found that feeding harmane alone to mosquitos, or allowing it to be absorbed through direct contact produced the same results, but the inhibitory effects only lasted a few days (2).
No matter how harmane is introduced into the gut (directly or through bacterial colonization), the inhibition of oocyte formation results in a decrease in infectivity. Only one third (33%) of mice bitten by Plasmodium-infected, D. tsuruhatensis-colonized mosquitos become infected. This contrasts sharply with the 100% infection rate seen with mice bitten by non-colonized, Plasmodium-infected mosquitos (2). Further testing the researchers also showed that D. tsuruhatensis is not transferred during feeding, suggesting that that bacterium is unlikely to in introduced into mammals through colonized mosquitos.
To investigate how colonization and infection rates would correlate in a ‘real world’ environment, the researchers used a large (10 × 10 × 5 meter) enclosure that replicated the mosquitos’ natural environment. Once again, the mosquitos were colonized with D. tsuruhatensis through overnight feeding of the sugar and bacterium solution. They found ~75% of the mosquitos were colonized by D. tsuruhatensis in this time period.They also found that larvae reared in water seeded with D. tsuruhatensis experienced 100% colonization. In both scenarios, Plasmodium oocyte development was disrupted just as it had been in the laboratory-raise population (2).
Finally, the researchers found that D. tsuruhatensis colonization doesn’t occur between individuals between parent and offspring. For controlling Plasmodium, this means that inoculation with D. tsuruhatensis would require ongoing maintenance. However, it also decreases the risk of a contaminated strain being amplified uncontrollably if released, making it less risky.
Malaria mitigation and control requires a multipronged effort. Using naturally occurring, symbiotic, microbes such as D. tsuruhatensis is one approach that shows promise. There is still a lot of work to be done before this bacterium could be used outside of a controlled environment, including understanding how the bacterium might interact with other plants and animals from the same ecosystem.
References
Monitoring and quantifying drug-target binding in a live-cell setting is important to bridging the gap between in vitro assay results and the phenotypic outcome, and therefore represents a crucial step in target validation and drug development (1). The NanoBRET™ Target Engagement (TE) assay is a biophysical technique that enables quantitative assessment of small molecule-target protein binding in live cells. This live-cell target engagement assay uses the bioluminescence resonance energy transfer (BRET) from a NanoLuc® luciferase-tagged target protein and a cell-permeable fluorescent tracer that reversibly binds the target protein of interest. In the presence of unlabeled test compound that engages the target protein, the tracer is displaced, and a loss of BRET signal is observed. Due to the tight distance constraints for BRET, the signal measured is specific to the target fused to NanoLuc® luciferase.
Promega offers over 400 ready-to-use assays for multiple target classes, including kinases, E3 ligases, RAS, and many others. For targets that do not have an existing NanoBRET™ TE assay, Promega offers NanoBRET™ dyes, NanoLuc® cloning vectors, and NanoBRET™ detection reagents to develop novel NanoBRET™ TE assays.
To learn more about the NanoBRET™ TE platform, see the NanoBRET™ Target Engagement Technology Page on our website.
One critical component in the development of novel NanoBRET™ TE assay is the creation of the cell-permeable fluorescent tracers (NanoBRET™ tracers) against the target protein of interest. The tracers are bifunctional, consisting of a NanoBRET™-compatible fluorophore and a target-binding moiety connected by a linker. While the NanoBRET™ 590 dyes have demonstrated consistently robust cell permeability and optimal spectral overlap with NanoLuc® for BRET, a ligand capable of binding to the target protein of interest needs to be identified to generate a NanoBRET™ tracer.
DNA-Encoded Libraries, (DELs), have emerged as powerful tools for discovering small molecule ligands to target proteins of interest at an unprecedented scale. . owing to the ability of a DEL to enable the synthesis of larger libraries of compounds and to target proteins without any prior structural knowledge of the proteins or their ligands (2). Because each member of a DEL contains a DNA barcode and a small molecule separated by a linker, DEL is primed for discovering leads within therapeutic modalities that rely on bifunctional chemistry, such as proteolysis targeting chimeras (PROTACs). Since NanoBRET™ tracers are also bifunctional, ligands identified from DEL selections could serve as ideal candidates for developing novel NanoBRET™ tracers that can enable NanoBRET™ TE assays for new targets.
Continue reading “From Hit to Live-Cell Target Engagement Assay: DNA-Encoded Library Screens and NanoBRET™ Dye”Last year’s International Symposium of Human Identification (ISHI) covered a span of topics during various workshops, sessions, and poster presentations. Topics ranged from investigative genetic genealogy (IGG) to customary updates about CODIS and DNA testing standards to mobilizing DNA analysis labs. However, one topic particularly stood out to attendees—Ashley Spence’s powerful testimony on pursuing justice for victims.
Continue reading “Pursuing Justice For Victims: DNA Forensics”