A scientific article led by my colleague Dr. Alaa Rabee at the Desert Research Center in Egypt was just published online and is now available! Dr. Rabee and I have been collaborating remotely on projects related to the bacteria in the rumen of camels, sheep, and cows, as Dr. Rabee’s work focuses on the isolation of bacteria which can degrade plant materials efficiently and could be used to produce biofuels. He will be spending 6 months working in my lab as a visiting scholar, which was delayed until this year because of the pandemic.
Rabee, A.E., Sayed Alahl, A.A., Lamara, M., Ishaq, S.L. 2022. Fibrolytic rumen bacteria of camel and sheep and their applications in the bioconversion of barley straw to soluble sugars for biofuel production. PLoS ONE 17(1): e0262304. Article.
Abstract
Lignocellulosic biomass such as barley straw is a renewable and sustainable alternative to traditional feeds and could be used as bioenergy sources; however, low hydrolysis rate reduces the fermentation efficiency. Understanding the degradation and colonization of barley straw by rumen bacteria is the key step to improve the utilization of barley straw in animal feeding or biofuel production. This study evaluated the hydrolysis of barley straw as a result of the inoculation by rumen fluid of camel and sheep. Ground barley straw was incubated anaerobically with rumen inocula from three fistulated camels (FC) and three fistulated sheep (FR) for a period of 72 h. The source of rumen inoculum did not affect the disappearance of dry matter (DMD), neutral detergent fiber (NDFD). Group FR showed higher production of glucose, xylose, and gas; while higher ethanol production was associated with cellulosic hydrolysates obtained from FC group. The diversity and structure of bacterial communities attached to barley straw was investigated by Illumina Mi-Seq sequencing of V4-V5 region of 16S rRNA genes. The bacterial community was dominated by phylum Firmicutes and Bacteroidetes. The dominant genera were RC9_gut_group, Ruminococcus, Saccharofermentans, Butyrivibrio, Succiniclasticum, Selenomonas, and Streptococcus, indicating the important role of these genera in lignocellulose fermentation in the rumen. Group FR showed higher RC9_gut_group and group FC revealed higher Ruminococcus, Saccharofermentans, and Butyrivibrio. Higher enzymes activities (cellulase and xylanase) were associated with group FC. Thus, bacterial communities in camel and sheep have a great potential to improve the utilization lignocellulosic material in animal feeding and the production of biofuel and enzymes.
The Microbes and Social Equity working group has published its second collaborative paper together, led by Dr. Jake Robinson and featuring 25 other MSE group researchers in various fields related to microbiomes, social equity, and ecosystems. In developing this paper, we had many conversations about what had been accomplished in research related to microbial exposure, as well as what had yet to be done. We provide some background information as context, and spend the majority of the paper outlining twenty of the most poignant research directions. There are so many questions yet to be answered about the way the microbial communities interact with human lives, and how our lives impact them back. In our enthusiasm for the topics, we could have endlessly chatted about research, such that we decided to limit ourselves to twenty questions. We hope that this piece becomes a source for inspiration for others who continue this conversation and future research in these areas.
You can find a link below to read the full article, and links to the authors’ twitter feeds if you’d like to check them out on social media. You’ll be able to hear more about this publication in an upcoming seminar from Jake, as part of the 2022 MSE speaker series, which is open to all and free to attend over zoom.
Social and political policy, human activities, and environmental change affect the ways in which microbial communities assemble and interact with people. These factors determine how different social groups are exposed to beneficial and/or harmful microorganisms, meaning microbial exposure has an important socioecological justice context. Therefore, greater consideration of microbial exposure and social equity in research, planning, and policy is imperative. Here, we identify 20 research questions considered fundamentally important to promoting equitable exposure to beneficial microorganisms, along with safeguarding resilient societies and ecosystems. The 20 research questions we identified span seven broad themes, including the following: (i) sociocultural interactions; (ii) Indigenous community health and well-being; (iii) humans, urban ecosystems, and environmental processes; (iv) human psychology and mental health; (v) microbiomes and infectious diseases; (vi) human health and food security; and (vii) microbiome-related planning, policy, and outreach. Our goal was to summarize this growing field and to stimulate impactful research avenues while providing focus for funders and policymakers.
Over the summer, an article was published which featured a handful of researchers from across the US and research spanning a decade on the bacterial communities associated with invasive ants and nematodes in Maine. At the time, we were invited to also contribute a “Backstory” article to the scientific journal iScience which described the journey and the ideas.
That story authored by myself and Ellie Groden (senior researcher on the journal article) has just been published, and can be found here. I’d like to thank Dr. Sheba Agarwal, who was the editor on the paper, helped us develop our Backstory, and also spoke to me about this and other work as a guest on the WeTalkScience podcast.
It doesn’t seem that long ago that we were just an assorted group of interested researchers having a chat, but here we are two years later gaining international support and interest. We greatly appreciate your interest in this group, and are pleased to share some of our recent updates.
We currently have 115 members of the Microbes and Social Equity working group, and another 33 people signed up just for the newsletter. In 2021, we ran a very successful speaker series, virtual symposium, and collectively had quite a few publications, presentations, and developments! We are excited to continue that momentum in 2022, and are planning another speaker series and virtual symposium, finalizing our journal special collection with mSystems, and furthering the collaborative projects we have begun. We will also be adding additional leadership roles for the group, to better accommodate our group and give more attention to our growing activities and initiatives.
Melissa Manus recently authored a paper in Microbial Ecology, “Ecological Processes and Human Behavior Provide a Framework for Studying the Skin Microbial Metacommunity.” Melissa added: “I recently published a review on the skin microbiome– in short, calling for a dual consideration of ecological theory and human behavior to better understand (and test) how microbes are dispersed to the skin and between body sites. I make a quick plug for thinking about microbes and social equity, too!”
mSystems Special Collections:
We are making great progress adding to our special collection with mSystem, with 3 papers published and several more currently in review! We will continue adding contributions through 2022.
Francisco Parada’s postdoc, Dr. Ismael Palacios-García finished collecting his probiotic/lifestyle randomized trial, collecting cognitive electrophysiology (EEG+EGG), microbial (DNA from fecal samples), and phenomenological data (questionnaires) over 4+ months. They hope they will be publishing some of these results soon!
Jake Robinson is working on “Invisible Friends”, a popular science book anticipated for release in 2022. From Jake’s page: “Invisible Friends is about our extraordinary relationship with microbes, and how they shape our lives, our health, and the world around us. The book aims to challenge the prevailing negative perception of microorganisms, by highlighting the weird, wonderful, and indispensable roles they play in our health, behaviour, society, and ecosystems!”
Presentations
Upcoming:
The Microbes and Social Equity speaker series 2022 is under development! We hope to invite speakers for a virtual series running January through April, Wednesdays from 12:00 – 13:00 EST. Registration is required but the series is free to attend.
inVIVO Planetary Health, virtual conference, Dec 1-7, 2021. Register here. Several MSE group members will be giving talks there, such as:
Sue Ishaq, “Introducing the Microbes and Social Equity Working Group: Considering the Microbial Components of Social, Environmental, and Health Justice”
Ari Kozik, “The human microbiome and health disparities: restoring dysbiosis as a matter of social justice”
Jake Robinson, “Microbiome-inspired green infrastructure (MIGI): a bioscience roadmap for urban ecosystem health”
2nd Rhode Island Microbiome Symposium, in person conference, University of Rhode Island Kingston, RI, January 14, 2022. Register here.
Sue Ishaq, ”Microbes at the nexus of environmental, biological, and social research”
American Society for Microbiology (ASM) Microbe 2022, in person conference, Washington, DC (USA), June 9-13, 2022.
‘Field Work & DEI Part 1: Fostering Equitable Partnerships with the Communities in Your Field Work Location’. The session’s date is June 11, 2022 (11:45AM – 12:30PM).
Ishaq,”Microbes and Social Equity: what is it and how do we do it?”
MSE special session, “Microbes and Social Equity: the Microbial Components of Social, Environmental, and Health Justice”. The session’s date is June 11, 2022 (1:45PM – 3:45PM), and the event is under development.
Featuring panelists Monica Trujillo, Ari Kozik, and Carla Bonilla
Past:
Mike Friedman hosted a very successful MSE Special Session (together with the Microbial Ecology section) at this year’s virtual Ecological Society of America meeting. Naupaka Zimmerman, Justin Stewart, Monica Trujillo and Sue Ishaq gave short presentations on social justice and various aspects of environmental and human microbiota. But the bulk of the session was taken up by audience discussion of issues in environmental justice and microbes, practical and suggested policies and education.
Olivia Choi, a doctoral candidate in the Kamath lab at the University of Maine, has had her first scientific paper accepted for which she is the first author – a position indicative of the amount of work and organization that she put into developing this work and wrangling the large research team involved. Olivia’s graduate work is winding down as she concentrates on writing up papers and her dissertation, and she is planning on defending her PhD and looking for a postdoc in 2022 in wild animal microbiomes and ecology.
Olivia brought this 16S rRNA dataset to use in my AVS590 data analysis class back in spring 2020, of bacterial communities in different locations on birds of different species, which had been sampled as part of her dissertation work on bird migration and range changes, microbial carriage, and risk of transmission of microbes to other animals. I mentored her through analysis and preliminary manuscript writing as part of that course. The research team generously invited me to join the author team, and I continued to provide mentorship as Olivia worked through the complex task of melding various types of microbiology data.
Studies in both humans and model organisms suggest that the microbiome may play a significant role in host health, including digestion and immune function. Microbiota can offer protection from exogenous pathogens through colonization resistance, but microbial dysbiosis in the gastrointestinal tract can decrease resistance and is associated with pathogenesis. Little is known about the effects of potential pathogens, such as Salmonella, on the microbiome in wildlife, which are known to play an important role in disease transmission. Recent studies have expanded the traditional use of 16S rRNA gene amplicon data from high-level characterization of host-associated microbial communities (i.e., the microbiome) to detection of specific bacteria. Few studies, however, have evaluated the ability of high-throughput 16S rRNA gene sequencing data to detect potential bacterial pathogensin comparison with laboratory culture-based methods. To address this knowledge gap, we evaluated the utility of 16S rRNA gene sequencing for potential pathogen detection and explored the relationship between potential pathogens and microbiota. First, we compared the detection of Salmonella spp. in barn swallows (Hirundo rustica) using 16S rRNA data with standard culture techniques. Second, we examined the prevalence of Salmonella using 16S rRNA data and examined the relationship between Salmonella presence or absence and individual host factors. Lastly, we evaluated host-associated bacterial diversity and community composition in Salmonella present versusabsent birds. Out of 108 samples, we detected Salmonella in 6 (5.6%), 25 (23.1%), and 3 (2.8%) samples based on culture, unrarefied 16S rRNA gene sequencing data, and both techniques, respectively. In addition, we found that Salmonella presence and absence differed between birds based on migratory status and weight and that bacterial community composition and diversity differed between Salmonella present versus absent birds, with eleven bacterial taxa differentially abundant between the two groups. The results of this study highlight the value of high-throughput 16S rRNA gene sequencing data for bacterial pathogen detection and for examining relationships between potential pathogens and host-associated microbial communities. Further, this study emphasizes an approach using 16S rRNA gene sequencing data for simultaneously monitoring multiple pathogens in wild avian reservoirs, which is important for prediction and mitigation of disease spillover into livestock and humans.
This work was presented at a recent scientific conference:
Funded by the University of Maine Rural Health and Wellbeing Grand Challenge Grant Program, this project assesses pathogen carriage by mice and flying squirrels on or near farms in several locations in Maine. We live-capture mice and flying squirrels in traps, collect the poop they’ve left in the trap, and conduct a few other health screening tests in the field before releasing them. To maximize the information we collect while minimizing stress and interference to the animals, information is being collected for other projects in the Levesque Lab at the same time. We will be collecting samples for another few weeks, and then working on the samples we collected in the lab over the fall and winter.
One of the major goals of the funding program, and this project, is to engage students in research. After a few months on the project, some of our students describe their role and their experiences so far…
Marissa Edwards
Undergraduate in Biology
Levesque Lab
Hi! My name is Marissa Edwards and I am an undergraduate research assistant with Danielle Levesque. This summer, my role has been to set traps, handle small mammals, and collect fecal and tissue samples from deer mice.
One of the skills I’ve learned this summer is how to properly ear tag a mouse. To catch mice, we set traps across UMaine’s campus as well as other parts of Maine, including Moosehead Lake, Flagstaff Lake, and Presque Isle.
During our trip to Moosehead Lake, I saw a marten for the first time (it was in one of our traps). I did not know martens existed and initially thought it was a fisher cat. It was both a cool and terrifying experience!
Elise Gudde
Master’s Student of Ecology and Environmental Sciences
Levesque Lab
Hello, my name is Elise Gudde, and I am currently a master’s student at the University of Maine in the Ecology and Environmental Sciences program. I work in Dr. Danielle Levesque’s lab studying small mammal physiology in Maine.
This summer, as a part of the squirrel project, I work to trap small mammal species in Maine, such as white footed mice, deer mice, and flying squirrels in order to determine which species have shifted their range distributions as a result of climate change. Being a part of the research team, this summer has brought me all over Maine! I have been able to travel to Orono, Greenville, New Portland, and Aroostook County to study many interesting mammals. I even got to handle an Eastern chipmunk for the first time! As a member of the animal-handling side of the research team, I also collect fecal and tissue samples from the animals. These samples are then handed off for other members of the team to research in the lab!
Rebecca French
Undergraduate in Animal and Veterinary Sciences
Ishaq Lab
In the beginning of this project, I had no idea what I was getting myself into when I began researching flying squirrels and mice. I came into it with almost no in-person lab experience, so I had a lot to learn.
So far, I have been focusing on making media on petri dishes for culturing bacterial growth and after plating fecal bacteria on said plates; discerning what that growth can be identified as.
We are using media with specific nutrients, and colored dyes, and certain bacteria we are interested in will be able to survive or produce a color change. I have also been performing fecal flotations and viewing possible eggs and parasites under a microscope. What I’ve found most fun about this project is putting into practice what I have learned only in a classroom setting thus far. It is also very satisfying to be a part of every step of the project; from catching mice, to making media, to using that media to yield results and then to be able to have a large cache of information to turn it all into a full fledged project.
Some of the media used to culture bacteria from the feces of mice and squirrels.
Joe Beale
Undergraduate in Animal and Veterinary Sciences
Kamath Lab
Hello! My name is Joseph Beale, and I am an undergraduate at the University of Maine working on the squirrel project as a part of my capstone requirement for graduation. My primary responsibility in this project is the molecular testing of samples obtained from the field. Primarily I will be working with ear punch samples taken from flying squirrels and field mice. DNA extracts from these field samples will be run via qPCR. The results of this qPCR will tell us if these squirrels are carrying any pathogens.
The pathogens we will be testing for are those found in Ixodes ticks. The qPCR panel which we will be running the extracted DNA from the ear punches on tests for Borrelia burgdorferi, the causative agent of Lyme disease, Anaplasma phagocytophilum, the causative agent of anaplasmosis, and Babesia microti, the causative agent of Babesiosis. These pathogens and respective diseases discussed are all transmitted through Ixodes ticks. Deer ticks are the most common and famous of the Ixodes genus. The Ixodes genus encapsulates hard-bodied ticks. Along with deer ticks, Ixodes ticks found in Maine include: woodchuck ticks, squirrel ticks, mouse ticks, seabird ticks, and more. Mice and squirrel are ideal hosts for these Ixodes ticks, therefore becoming prime reservoirs for these diseases. In our research, we are interested in determining the prevalence of these diseases in squirrels and mice as these hosts can spread these diseases to humans and other animals in high tick areas.
qPCR, quantitative polymerase chain reaction, allows for the quantification of amplified DNA in samples. This will help tell us if these pathogens are present in samples and in what capacity. In qPCR provided DNA strands are added to the reaction. These strands match with the genome of the intended pathogens. If the pathogens are present in our samples, the provided DNA strands will bind to the present pathogen DNA. PCR will then work to manufacture billions of copies of this present pathogen DNA.
When not working on this project, I also work in the University of Maine Cooperative Extension Diagnostic Research Laboratory as a part of the Tick Lab. In this position I have honed the molecular biology skills that I will in turn use for the squirrel project.
Hello everyone! My name is Yvonne Booker and I am a rising senior, animal and poultry science major at Tuskegee University in Tuskegee, Alabama. I am interested in animal health research, with a particular focus in veterinary medicine. I’ve always wanted to be a veterinarian, but as I progressed throughout college, I became interested in learning more about animal health and how I might help animals on a much larger and impactful scale–which led me to the REU ANEW program. Currently climate change is causing an increase in global temperatures, putting pressure on animals’ ability to interact and survive within their environment. Consequently, scientists are now attempting to understand not just how to prevent climate change, but how these creatures are adapting to this emerging challenge.
My research experience this summer is geared toward addressing this global issue. I am currently working in Dr. Danielle Levesque’s Lab, which aims to study the evolutionary and ecological physiology of mammals in relation to climate. My project involves conducting a literature review of the microbiome of mammals, to learn more about how their microbial community plays a role in how they adapt in a heat-stressed environment.
Our knowledge of vertebrate-microbe interactions derives partly from research on ectotherms. While this research paves the path for a better understanding of how organisms react to temperature changes, fewer studies have focused on how mammals deal with these extreme temperature shifts—specifically, the abrupt surge in climate change. The ability of endotherms to thermoregulate alters our knowledge of (1) how mammals create heat tolerance against these environmental challenges and (2) how this internal process alters mammals’ adaptability and physiology over time. We suggest that the microbiome plays an essential part in understanding mammals’ heat tolerance and that this microbial community can help researchers further understand the various processes that allow mammals to survive extreme temperatures.
As a student of the REU ANEW program my goal was to go out of my comfort zone and study animals in an applied fashion that would impact animal health on an environmental and ecological scale; and this program was just that! My mentor, Dr. Levesque was wonderful in guiding me through conducting this research, while giving me the independence to create my own voice. The program directors, Dr. Anne Lichtenwalner and Dr. Kristina Cammen, have also been extremely supportive throughout this entire program equipping students with the tools they need to succeed as researchers. Although research was my primary focus this summer, some of my favorite memories involved building community with the students and the staff. From weekly check-ins on zoom to virtual game nights of complete smiles and laughter, this program has been one for the books! The One Health and the Environment approach to this Research Experience for Undergraduate students has encouraged me to build on my curiosity within the field of science, and I’m looking forward to applying what I’ve learned to my career in the future.
Did you know that camels have three stomach chambers or that they have to throw up their own food in order to digest their food properly? Have you felt excluded from science spaces before? Then this blog post is for you!
Allow me to introduce myself.
My name is Myra, and I am a rising senior at SUNY Stony Brook University, where my major is Ecosystems and Human Impact, with a biology minor. In a nutshell, my major is interdisciplinary with a focus on conservation and ecology within human societies.
If I were to describe my college experience in one word I’d pick “surprises”. I never actually saw myself being a scientist in my middle and high school years. I found it hard to care about abstract concepts or theories that felt so far removed from humanity, particularly minority communities. But, during college I found myself falling in love with environmental studies, and along with it, the beautiful complexities that come with being human in our increasingly anthropogenic world.
At UMaine, we focus on the One Health Initiative, which views the health of humans, animals, and the environment as interconnected. When COVID-19 caused everyone to go into lockdown, I was fortunate to find this farm was looking for crew members, with a focus on food security. While certainly not how I planned to spend the summer of 2020, farming for underserved communities is where I saw how impactful One Health was. Organic farmers commonly use plastic mulch as a popular alternative to pesticides for weed suppression. At my home institution, I lead a project on the impacts of microplastics on earthworm health, an Ecotoxicology lab (students of the lab affectionately gave it the nickname “the Worm lab”). We use earthworm health as an indicator of soil health, which in turn is crucial for crop flourishment. The Worm Lab and farming emboldened me to pursue science and, ergo, look for this REU!
At UMaine, I am a member of the Ishaq Lab where I work on the camel metagenome project. Basically, scientists in Egypt raised camels on different diets, then used samples from their feces to sequence their microbial genome. These microbes live in the camel rumen (part of the camel stomach), and help the camel digest their food. What I do with Dr. Ishaq’s lab is, I perform data analysis on these sequences to see how the microbial gene profile changes with different diets. Camels are essential for transportation and food for the communities that rely on them, so finding the most efficient feed for them is important. Camels also release methane depending on their diet so it’s possible humans could control methane production of camels through their diet.
Being a part of the REU ANEW program for 2021 definitely has been an interesting experience, since it is the first time this program has been conducted virtually. Even though I would have loved to have seen everyone in person and spent time in lovely Orono, Maine, I’m glad for the research opportunity as it has further solidified my love of research and the One Health initiative.
Myra’s poster for the REU Research Symposium, virtual, Aug 13, 2021.
The Microbes and Social Equity Working Group is delighted to make its published debut, with this collaboratively-written perspective piece introducing ourselves and our goals. You can read about us here.
This piece also debuts the special series we are curating in partnership with the scientific journal mSystems; “Special Series: Social Equity as a Means of Resolving Disparities in Microbial Exposure“. Over the next few months to a year, we will be adding additional peer-reviewed, cutting edge research, review, concept, and perspective pieces from researchers around the globe on a myriad of topics which center around social inequity and microbial exposures.
Ishaq, S.L., Parada, F.J., Wolf, P.G., Bonilla, C.Y., Carney, M.A., Benezra, A., Wissel, E., Friedman, M., DeAngelis, K.M., Robinson, J.M., Fahimipour, A.K., Manus, M.B., Grieneisen, L., Dietz, L.G., Pathak, A., Chauhan, A., Kuthyar, S., Stewart, J.D., Dasari, M.R., Nonnamaker, E., Choudoir, M., Horve, P.F., Zimmerman, N.B., Kozik, A.J., Darling, K.W., Romero-Olivares, A.L., Hariharan, J., Farmer, N., Maki, K.A., Collier, J.L., O’Doherty, K., Letourneau, J., Kline, J., Moses, P.L., Morar, N. 2021. Introducing the Microbes and Social Equity Working Group: Considering the Microbial Components of Social, Environmental, and Health Justice. mSystems 6:4.
A collaborative paper on bacterial transfer in insects and the possible ecological impacts of that in the wild has been published in iScience! This work began a decade ago in the labs of Dr. Ellie Groden, recently retired Professor of Entomology in the School of Biology and Ecology at the University of Maine, and later Dr. Patricia Stock, a Professor in the School of Animal and Comparative Biomedical Sciences at the University of Arizona, who were investigating colony collapse of European fire ants (Myrmica rubra) which are invasive to Maine. The ants have a nasty bite, and can dramatically disturb the local plant and insect wildlife in coastal Maine.
Slide from Ishaq et al. Entomology 2020 presentation
When these invasive ant colonies collapsed, Drs. Groden and Stock wanted to find out why, as a possible means of developing a biological control strategy. It was thought that particular nematodes would ingest soil bacteria, and transfer it to ants once the worms invaded ant tissues to complete parts of their life cycle. This particular worm infection doesn’t kill the ants, but perhaps the soil bacteria were. Ants were collected from different colony sites, and investigations on the nematode worms inhabiting the ants were conducted.
Slide from Ishaq et al. Entomology 2020 presentation
Most of the work for this project was completed several years ago, with the exception of DNA sequencing data from a bacterial transfer experiment. I was added to the project by my collaborator at UMaine, Dr. Jean MacRae, an Associate Professor in the Department of Civil and Environmental Engineering who introduced me to the research team and shared the 16S rRNA dataset to use in my AVS 590 data analysis class in spring 2020. That semester was when the pandemic hit, and forced the course to move to remote-only instruction in March. UMaine graduate students Alice Hotopp and Sam Silverbrand were taking the class and learning 16S analysis on this dataset, and I mentored them through the analysis all the way to manuscript writing despite the incredible challenges that spring threw our way.
At the completion of the course, we shared the draft manuscript with the rest of the research team, who mentioned that several undergraduate honor’s theses had been written about the earlier experiment, but never published in a scientific journal. The team spent summer 2020 combining the three papers into one massive draft. The pandemic slowed down manuscript review, understandably, but I’m pleased to say that it was accepted for publication! In addition, this collaboration has led to further collaborations in the Ishaq Lab, several presentations (listed below), and is Sam’s first scientific publication, congrats Sam!!
Related Presentations
Alice Hotopp, A., Samantha Silverbrand, Suzanne L. Ishaq, Jean MacRae, S. Patricia Stock, Eleanor Groden. “Can a necromenic nematode serve as a biological Trojan horse for an invasive ant?” Ecological Society of America 2021 (virtual). Aug 2-6, 2021 (accepted poster).
Ishaq*, S.L., Hotopp, A., Silverbrand, S., MacRae, J., Stock, S.P., Groden, E. “Can a necromenic nematode serve as a biological Trojan horse for an invasive ant?” Entomological Society of America 2020 (virtual). Nov 15-25, 2020. (invited talk)
The necromenic nematode Pristionchus entomophagus has been frequently found in nests of the invasive European ant Myrmica rubra in coastal Maine, United States, and may contribute to ant mortality and collapse of colonies by transferring environmental bacteria. Paenibacillus and several other bacterial species were found in the digestive tracts of nematodes harvested from collapsed ant colonies. Serratia marcescens, Serratia nematodiphila, and Pseudomonas fluorescens were collected from the hemolymph of nematode-infected wax moth (Galleria mellonella) larvae.
Virulence against waxworms varied by site of origin of the nematodes. In adult nematodes, bacteria were highly concentrated in the digestive tract with none observed on the cuticle. In contrast juveniles had more on the cuticle than in the digestive tract. . Host species was the primary factor affecting bacterial community profiles, but Spiroplasma sp. and Serratia marcescens sequences were shared across ants, nematodes, and nematode-exposed G. mellonella larvae.
A study was recently published, led by Dr. Huawei Zeng, USDA Animal Research Station, on gut health, nutrition, and gut microbiota! I contributed analysis and interpretation for the gut community data, and though I appear as last author on this publication, it is truly because I contributed the least and not because I was administrative lead or the lead PI. I have worked with Dr. Zeng for several years, although we have never met in person,
Adoption of an obesogenic diet low in calcium and vitamin D (CaD) leads to increased obesity, colonic inflammation, and cancer. However, the underlying mechanisms remain to be elucidated. We tested the hypothesis that CaD supplementation (from inadequacy to adequacy) may reduce colonic inflammation, oncogenic signaling, and dysbiosis in the colon of C57BL/6 mice fed a Western diet. Male C57/BL6 mice (4-week old) were assigned to 3 dietary groups for 36 weeks: (1) AIN76A as a control diet (AIN); (2) a defined rodent “new Western diet” (NWD); or (3) NWD with CaD supplementation (NWD/CaD). Compared to the AIN, mice receiving the NWD or NWD/CaD exhibited more than 0.2-fold increase in the levels of plasma leptin, tumor necrosis factor α (TNF-α) and body weight. The levels of plasma interleukin 6 (IL-6), inflammatory cell infiltration, and β-catenin/Ki67 protein (oncogenic signaling) were increased more than 0.8-fold in the NWD (but not NWD/CaD) group compared to the AIN group. Consistent with the inflammatory phenotype, colonic secondary bile acid (BA, inflammatory bacterial metabolite) levels increased more than 0.4-fold in the NWD group compared to the NWD/CaD and AIN groups. Furthermore, the abundance of colonic Proteobacteria (e.g., Parasutterela), considered signatures of dysbiosis, was increased more than 4-fold; and the α diversity of colonic bacterial species, indicative of health, was decreased by 30% in the NWD group compared to the AIN and NWD/CaD groups. Collectively, CaD adequacy reduces colonic inflammation, β-catenin oncogenic signaling, secondary BAs, and bacterial dysbiosis in mice fed with a Western diet.
This is part of a multi-year collaboration, with previous publications:
Zeng, H., Ishaq, S.L., Liu, Z., Bukowski, M.R. 2017. Colonic aberrant crypt formation accompanies an increase of opportunistic pathogenic bacteria in C57BL/6 mice fed a high-fat diet. Journal of Nutritional Biochemistry 54:18-27. Impact 4.418. Article.
Zeng, H., Ishaq, S.L., Zhao, F-Q., Wright, A-D.G. 2016. Colonic inflammation accompanies an increase of b-catenin signaling Lachnospiraceae/Streptococcaceae in the hind-gut of high-fat diet-fed mice. Journal of Nutritional Biochemistry 25:30-36. Impact 4.518. Article
