TS Digest Issue | October 2024, Issue 2 | Science Experiments from the Afterlife

Researchers found human antibody candidates that neutralize the toxin of European black widow venom.

Article

Antibody Potion Against Black Widow's Bite

Scientists brewed recombinant human antibodies that take the sting out of the European black widow’s toxin.

Laura Tran, PhD

Oct 15, 2024 | 2 min read

Image Credit:

modified from © istock.com, Syuzanna Guseynova, AnnaSqBerg, sorbetto, powerofforever; Designed by Erin Lemieux

Biologists Michael Hust (left) and Maximilian Ruschig (right) at the Technical University of Braunschweig found human antibody candidates that neutralize the toxin of European black widow bites.

Michael Hust

The thought of black widow spiders is enough to send chills down one’s spine. Their painful bites contain a cocktail of chemicals, primarily the highly conserved alpha-latrotoxin (α-LTX). This toxin induces latrodectism, an illness causing severe pain. Horse-derived antibodies treat these bites but cause serious allergic reactions, prompting biologist Michael Hust from the Technical University of Braunschweig to seek safer alternatives.

“The main problem is that latrodectism is considered a low-incidence disease, and [horse antisera] is a good enough therapy,” said Maximilian Ruschig, a graduate student in Hust’s group. Despite the adverse reactions, “It’s difficult to replace a working product with a new and better product,” said Hust.

The team turned to human antibodies to minimize these risks and enhance treatment effectiveness. Their study, published in Frontiers in Immunology, reported human antibodies that neutralized the toxin of European black widow spiders (Latrodectus tredecimguttatus), offering potential candidates for developing therapeutics.¹

Hust’s team used antibody phage display to select antibodies against α-LTX from a library with more than 10 billion different recombinant antibodies. Then, Ruschig developed a cell-based assay to test their effectiveness against α-LTX’s cytotoxic effects. He found that 45 of the 75 generated antibodies bound and neutralized α-LTX.

Next, the researchers tested their top candidates against α-LTX from a different Latrodectus species to study their cross protection. “What stood out was that they also looked at cross-reactivity,” said Andreas Laustsen-Kiel, a bioengineer at the Technical University of Denmark, who was not involved in the study. “They took this notion that it’s important to make a broadly neutralizing antibody.” However, the team was surprised to find that only two out of 14 antibodies cross-neutralized between the whole venom of European and Southern black widows, suggesting structural differences in α-LTX that require further investigation.

Nevertheless, the team believes these engineered antibody candidates could aid in developing effective human-derived antivenom against Latrodectus species, weaving a new web of hope for black widow bite victims.

Reference

Ruschig M, et al. Front Immunol. 2024;15:1407398.

Lucid Resipher Device 96-well microplate lid

Article

A Simple Cell Culture Intervention for Healthier Cells

Monitoring and manipulating cell culture oxygen consumption rates enables more physiologically-relevant in vitro models.

Oct 15, 2024 | 2 min read

Image Credit:

lucid scientific

Created in collaboration with

Learn More

When scientists grow cells in culture, they fine tune factors such as medium ingredients, cell number, and incubator temperature to mimic the human body. However, one culture condition that researchers often overlook is oxygen consumption.

“Cells are grown in aqueous medium and there's a cell monolayer, which generates an oxygen sink where cells are consuming oxygen at the bottom of the petri dish,” explained Joycelyn Tan, cellular biologist at Memorial Sloan Kettering Cancer Center. “Even though you have a lot of oxygen in the atmosphere, once the oxygen enters a liquid, it diffuses much more slowly. And considering that oxygen is usually consumed by the cells at one end of the liquid, this further reduces the amount of oxygen available in the cellular microenvironment," Tan added in an email.

While completing her graduate studies at University of Cambridge's Institute of Metabolic Science, Tan explored the relationship between cell culture oxygen concentration and cellular metabolism. In recent work published in EMBO Journal, Tan and her colleagues investigated how cultured adipocytes consume oxygen and the effects of modulating oxygen consumption rates (OCR).¹ The researchers used the Resipher Device by Lucid to measure live OCR in cell culture and found that standard cell culture conditions can be functionally hypoxic.

“The oxygen environment of the incubator is not an accurate representation of the oxygen concentrations that your cells are actually experiencing,” Tan said. “It can affect many aspects of cell metabolism and cell function, and that ultimately impinges on the reliability of the experimental findings that we get from in vitro experiments.” By lowering the media volume, and thus increasing the pericellular oxygen, Tan observed lowered hypoxia signaling and transcriptional rewiring that recapitulated a healthier adipocyte cell model.

“This observation that manipulating oxygen can improve cell function is especially important because it's a simple intervention that everyone can do to make their cell model a little bit closer to cells that are in a human body,” Tan said. “I think measuring OCR is taking us one step closer to more accurate and detailed reporting.”

Learn more about detecting oxygen consumption rates in cell culture.

What feature of your cultures do you wish to better monitor?

Submit Your Answer

Reference

Tan J, et al. EMBO J. 2024;43: 2127-2165.

Infographic

A Spider-Web Trap to Monitor Environmental DNA

Sticky spider-web traps are promising non-invasive and cheap tools for terrestrial vertebrate monitoring.

Mariella Bodemeier Loayza Careaga, PhD

Oct 15, 2024 | 1 min read

Scientists use environmental DNA (eDNA) to surveil animal biodiversity. Depending on the source—soil, water, permafrost—DNA shows different degradation rates and can provide a limited picture of the local biodiversity. In search of new and accessible eDNA sources, researchers from Curtin University tested spider webs as natural and easy-to-use biomonitoring tools.¹

The infographic shows a new method where researchers used spider webs to monitor environmental eDNA of vertebrates. They demonstrated the effectiveness of their by analyzing samples from a zoo and a wildlife sanctuary.

Modified from © istock.com, Logorilla, visualgo, dejanj01, Inna Miller, Rungnaree Jaitham; designed by erin lemieux

Reference

Newton JP, et al. iScience. 2024;27(2):108904.

Fluorescent microscopy image of a human body louse (appearing green) with two red ovoid shapes in its head (mCherry-expressing Yersinia pestis).

Article

A New Culprit in the Spread of Plague

Yersinia pestis, infamous for the cause of the Black Death, may have hitched a ride on parasites beyond just fleas.

Shelby Bradford, PhD

and

Uzma Rentia

Oct 15, 2024 | 2 min read

Image Credit:

David Bland/NIH NIAID

In 1898, scientists identified fleas as the vector for Yersinia pestis, the causative agent of the medieval Black Death and at least two other plagues. However, more recent outbreaks and reanalysis of the Black Death’s epidemiology questioned whether other human parasites, such as body lice, could also transmit the bacteria.¹

A team at the Rocky Mountain Laboratories of the National Institute of Allergy and Infectious Diseases (RML NIAID) dug into this question and demonstrated that these creepy crawlies could harbor and transmit plague.² The findings, published in PLoS Biology, introduce a new method of plague transmission by body lice.

“I didn't expect this finding because human body lice had been investigated in the past as plague vectors, but the results were kind of a little bit conflicting,” said Joseph Hinnebusch, a study author and microbiologist recently retired from RML NIAID. However, previous studies used lice adapted to feed on animals instead of human blood, which could have contributed to the poor transmission.

To investigate where Y. pestis colonized the body lice, the team engineered the bacteria to express a fluorescent marker. The researchers then fed lice human blood contaminated with Y. pestis before transferring them to sterile blood. They observed that infected lice harbored bacteria in their abdominal region or in localized areas in their heads within salivary-like glands. By grouping lice based on their bacterial localization and introducing the parasites to sterile blood, the team determined that lice with Y. pestis in these glands transmitted bacteria more rapidly and efficiently than when the bacteria was in the gut.

“It is a very important advance in research,” said Mireille Harimalala, an entomologist at the Institute Pasteur of Madagascar who wasn’t involved with the study. “Now we need to understand if, under natural conditions, lice can be also an important vector of the pathogen.”

References

Dean KR, et al. Proc Natl Acad Sci USA. 2018;115(6):1304-1309.
Bland DM, et al. PLoS Biol. 2024;22(5):e3002625.

Liquid biopsy and circulating tumor cells

Interview| Article

The Next Frontier: Circulating Tumor Cells and Liquid Biopsies

Improved methods for circulating tumor cell capture and analysis can ensure reproducible biomarker and omics insights across different cancer types.

Oct 15, 2024 | 2 min read

Image Credit:

Created in collaboration with

Learn More

Mouadh Barbirou, MSc PhD, explores the transformative potential of CTC analysis in cancer research and translational applications.

Mouadh Barbirou

Mouadh Barbirou, is a molecular biologist at the Sidney Kimmel Cancer Center of Thomas Jefferson University. As manager of the circulating tumor cell (CTC) core facility, Barbirou’s passion for biomedical science and commitment to bridging the gap between scientific discovery and clinical impact inspires their work investigating CTC-mediated cancer progression and treatment response.

Q: How do you capture CTCs?

We focus on processing liquid biopsy samples for CTC capture, enrichment, and downstream analysis, primarily focusing on breast cancer (BC), prostate cancer (PC), and head and neck squamous cell carcinoma (HNSCC). Tumor cell size and morphology, as well as relatively high circulating CTC concentrations in the bloodstream, contribute to the technical complexities of HNSCC CTC isolation and enrichment. Conversely, both BC and PC exhibit relatively favorable CTC capture and enrichment. Rather than applying distinct protocols for each cancer type, we prioritize consistency and homogeneity in our pipeline to ensure standardized and reproducible results. This allows us to establish a robust methodology that can be applied uniformly across diverse sample sets, facilitating accurate data comparisons and interpretation across different cancer types.

Q: Why is CTC detection important?

CTC abundance in the bloodstream often reflects the extent of tumor burden and metastatic spread in cancer patients. Generally, advanced cancer stages are associated with higher CTC numbers, whereas early-stage cancers may have fewer detectable CTC. Characterization holds immense promise for revolutionizing our understanding of cancer metastasis and its implications for diagnosis and treatment monitoring. Looking ahead, I envision CTC analysis making a profound impact across various domains of clinical oncology. One area of significant potential is the realm of liquid biopsy-based diagnostics. By harnessing the unique molecular signatures of CTC, we can develop non-invasive tests for early cancer detection, prognosis prediction, and treatment response monitoring.

Read the full article about the challenges of capturing and analyzing CTCs for clinical research and applications.

This interview has been condensed and edited for clarity.

What type of tumor cells do you wish you could capture in circulation?

Submit your Answer

A skull is seen on the forest floor; above it, magnified and in circles, are a blow fly, bacteria, and a carrion beetle.

Citizen Science Corner| Article

Science Experiments from the Afterlife

Forensic anthropologists, microbiologists, and entomologists study donated cadavers to determine how human bodies decompose.

Hannah Thomasy, PhD

Oct 15, 2024 | 2 min read

Image Credit:

Sibyl Bucheli (front left) explores how insect and microbe communities change over time during the process of decomposition.

Sibyl Bucheli

Not long after arriving at Sam Houston State University in 2007, entomologist and micromoth expert Sibyl Bucheli received a mysterious phone call that would change the course of her life.

“Are you going to the crime scene?” asked the voice on the other end of the line, without introduction or preamble. “No,” Bucheli replied, and hung up the phone.

Later, though, the woman on the phone, a researcher in the forensics department, brought part of the crime scene to Bucheli’s office. It was a human scalp. Intrigued, Bucheli examined it and identified several interesting moths, including the caterpillar stage of a case-making clothes moth. “In the wild, it eats dead and decomposing animals with fur,” said Bucheli. “And as the caterpillar gets larger, it increases the size of its silk shelter that it carries on its body.” In this instance, the caterpillar had enlarged its shelter using the deceased individual’s hair, from which the team successfully extracted mitochondrial DNA.¹ In the future, this technique could aid in identification, if detectives could access the caterpillar shelters but not the cadaver itself.

In the following years, Bucheli has worked extensively with the Southeast Texas Applied Forensic Science Facility (STAFS), a research center that accepts human body donations for the purpose of advancing scientific understanding of the biology of death. Bucheli explores the temporal patterns of insects and microbes present during various stages of human decomposition—work that is admittedly macabre, but provides an essential comparator for criminal death investigations. “Crime scenes are what we call a snapshot in time…you don’t know what happened before recovery,” said Bucheli. “At the body farm, we get this gift of time, this [ability to perform a] longitudinal study, which is really important.”

To learn more about becoming an integral part of this scientific endeavor posthumously, check out the information about body donation to STAFS or similar facilities.

Want to submit your own citizen science project? Tell us about it.

Submit Project

Reference

Bucheli SR, et al. J Forensic Sci. 2010;55(4):1130-1132.

Cartoon showing the neurons in the brain enjoying the frightening movie the person is watching.

Just Curious| Article

Why Do Some People Enjoy Horror Movies?

The enjoyment of a good scare may have more to do with relief than terror.

Shelby Bradford, PhD

and

Priyom Bose, PhD

Oct 15, 2024 | 2 min read

Image Credit:

Lauri Nummenmaa studies human emotions at the University of Turku.

Lauri Nummenma

Fear is an evolutionary response that protects against danger; when triggered, it activates circuits in the hypothalamus, midbrain, amygdala, and cortices, which generate a fight or flight response.^1-4 The pupils dilate, breath quickens, and the heart beats faster as one assesses their surroundings and prepares their next move.

In contrast, pleasure circuits throughout the brain respond to experiences that individuals enjoy or are good for survival, acting like rewards that drive people to seek them out again.⁵ This makes the notion of enjoying a sensation that mimics a survival threat seem contradictory, yet horror movies continue to draw crowds that voluntarily scare themselves. However, there is more going on between neurons than meets the eye.

“It's kind of a fluctuation between the threat systems and these pleasure systems that's likely going on in the brain,” said Lauri Nummenmaa, a neuroscientist and physiologist at the University of Turku. He and his team used functional magnetic resonance imaging while people watched horror movies and found that sensory regions contribute to the feeling of suspense and prepare the acute fight or flight circuits that activate when a reactionary fear response is triggered.⁶

The physiological response is also important to the overall satisfaction with the thrill, as studies investigating haunted house experiences showed a correlation between heart rate fluctuations and reported enjoyment.⁷

However, the fear itself doesn’t bring viewers back to their seats. “Part of the enjoyment of horror movies comes from the relief of the suspense,” Nummenmaa said. When the credits roll and movie-goers realize they survived the film, their brain’s pleasure circuits activate in response to the relief. Meanwhile, the exhilarating rush of adrenaline lingers, sparking a desire to relive the thrill. “The enjoyment, then, often results from the fact that we actually can experience these powerful emotions in a safe environment,” said Nummenmaa.

References

Knight DC, et al. Cogn Affect Behav Neurosci. 2004;4:317-325.
Qi S, et al. Proc Natl Acad Sci. 2018;115(12):3186-3191.
Kinreich S, et al. Brain Connect. 2011;1(6):484-495.
Etkin A, et al. Trends Cogn Sci. 2010;15(2):85-93.
Berridge KC, Kringelbach ML. Neuron. 2015;86(3):646-664.
Hudson M, et al. NeuroImage. 2020;216:116522.
Andersen MM, et al. Psychol Sci. 2020;31(12):1497-1510.

Rows of old, microbe-covered headstones in a misty graveyard with two leafless trees in the background.

Interview| Article

Microbial Tales from the Crypt

Rock-dwelling bacteria and eukaryotes live in the company of the dead by feeding on tombstones.

Danielle Gerhard, PhD

Oct 15, 2024 | 2 min read

Image Credit:

Amongst the ghostly whispers, murky fog, and eerie stillness of a graveyard is a haunting tale of decay. The tombstones that scatter a cemetery hold more than just the memory of the dearly departed—they are teeming with life. Tess Brewer, a microbial ecologist at Ludwig Maximilian University of Munich, discussed the patchwork of microbes that drape headstones.

Which microbes like to live on tombstones?

Microbes live on basically every surface on the planet, including rock surfaces, which are tough environments to survive on. For one of my graduate research projects, we analyzed samples collected from tombstones in nine countries and found many known rock-dwellers, including bacteria and fungi that belong to the genera Sphingomonas, Hymenobacter, Pseudonocardiaceae, and Sporichthyaceae and the phyla Actinobacteria and Ascomycota.¹ These microbes often have traits that help them survive environmental stressors like UV radiation and water scarcity.

How did rock type influence the kinds of microbes that inhabited the tombstone?

Although the communities varied by geographic location and climate, I was surprised by how the rock properties were key in determining what was growing on it. The microbes living on granite were very different from those living on limestone. In fact, granite tombstones in Belgium harbored communities that were more taxonomically similar to those on granite headstones in Maine than to those on neighboring limestone tombstones.

What is the effect of microbial colonization of rock surfaces?

Microbes can cause weathering, or the breakdown of rock. Bacteria, through normal metabolic processes, excrete acidic products that, depending on the rock type, can increase the local pH and eat away at the surface over time. Microbes can also impart mechanical forces—the contraction and expansion of biofilms and fungal hyphae can stress rock surfaces. Cemeteries offer a unique opportunity to study these kinds of weathering events since there are a variety of rock types and we can use the dates on the headstones as a rough estimate of time; however, microbes also wreak havoc on monuments and other stone surfaces.

Reference

Brewer TE, Fierer N. Environ Microbiol. 2018;20(3):958-970.