Student point of view on researching microbes, flying squirrels, and mice around farms in Maine

Five women taking a photo together at a farm.  They are standing a few feet apart from each other, and standing in front of a cow feedlot with two cows eating.

This summer, a collaborative project was launched by the Ishaq Lab, Danielle Levesque, and Pauline Kamath at UMaine Orono and Jason Johnston at UMaine Presque Isle; “Climate Change Effects on Wild Mammal Ranges and Infectious Disease Exposure Risk at Maine Farms.”

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…


A close-up of a deer mouse sitting in a live capture trap in the forest.  In the background is one of the researchers kneeling on the ground.

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.

A pine marten sitting in a live capture trap in a forest.

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!


Northern flying squirrel sitting on a net with a forest in the background.

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.

Northern flying squirrel sitting on a net with a forest in the background.

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 wearing a white laboratory coat, a fabric face mask, and beige latex gloves while using a yellow plastic loop tool to spread bactrial cultures on fresh agar media plates to look for growth.  Rebecca is sitting at a biosafety cabinet with the glass window slide down between her and what she is working on.  Assorted scientific materials can be seen in the background.

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.


Joe Beale, posing for a photo in an open office space.

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. 


Yvonne Booker

Undergraduate, Tuskeegee University

Levesque Lab

Microbes and the Mammalian Mystery“, reblogged from the University of Maine REU program.

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.

Rumening through camel microbes, by Myra Arshad

Written by Myra Arshad

Myra Arshad

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.

Interview with WeTalkScience: animal microbiome

A few weeks ago, I sat down with Sheba A-J, one of the producers of the WeTalkScience podcast, to talk about one of my recent publications in the research journal iScience, at which Sheba is also an editor. Listen to find out how lobsters are like humans, how I got involved on a project working with ants and nematodes, and how you can help make science a more welcoming place.

The full publication is:

Ishaq, S.L., A. Hotopp, S. Silverbrand, J.E. Dumont, A. Michaud, J. MacRae, S. P. Stock, E. Groden. 2021. Bacterial transfer from Pristionchus entomophagus nematodes to the invasive ant Myrmica rubra and the potential for colony mortality in coastal Maine. iScience 24(6):102663. Article.

Pilot project funded to study Vibrio bacteria in scallop farming

A collaborative pilot project was funded by the Maine Food and Agriculture Center (MFAC) to investigate Vibrio bacteria in scallop hatcheries in Maine! This will support some ongoing work by a collaborative research team at UMaine and the Downeast Institute, as we develop a long-term, larger-scale project investigating scallop health and survival in hatcheries, something which will be critical to supporting sustainable and economically viable aquaculture productions.

“Investigating microbial biofilms in Maine hatchery production of sea scallop, Placopecten magellanicus.”

Principal Investigator: Sue Ishaq

Co-Investigators:

  • Dr. Tim Bowden, Associate Professor of Aquaculture, University of Maine
  • Dr. Jennifer Perry, Assistant Professor of Food Microbiology, University of Maine
  • Dr. Brian Beal, Professor of Marine Ecology, University of Maine at Machias; and Research Director/Professor, Downeast Institute
  • Dr. Erin Grey, Assistant Professor of Aquatic Genetics, University of Maine

Project Summary: Atlantic deep-sea scallops, Placopecten magellanicus, are an economically important species, generating up to $9 million in Maine alone. Despite their potential to the aquaculture industry, hatchery-based sea scallop production cannot rely on the generation of larvae to produce animals for harvest. In hatcheries, the last two weeks of the larval maturation phase is plagued by massive animal death, going from 60 million scallop larvae down to a handful of individuals in a span of 48 hours. This forces farmed scallop productions to rely on collection of wild scallop spat (juveniles), but wild population crashes, habitat quality, harvesting intensity, and warmer water temperatures threaten the sustainability and economic viability of this industry. The reasons for sea scallop larvae death remain unknown, but other cultured scallop species are known to suffer animal loss from bacterial infections, including from several bacterial species of  Vibrio and Aeromonas. At the Downeast Institute in Beals, Maine, biofilms appear on tank surfaces within 24 hours. Routine screening for the presence of Vibrio sp. in tanks at DEI reveals no obvious signs of colonies in scallop tanks. Preliminary culturing and genetic identification from these biofilms suggests a species of Pseudoalteromonas, known biofilm formers which outcompete or inhibit other microorganisms. Our goal is to investigate the dynamics of tank surface biofilms in bivalve aquaculture facilities. Our long-term goals are to understand microbial community assembly and animal health during scallop hatchery production, and to standardize management practices to enhance the success of cultured scallop production.  

Experimental design schematic for this project. Our objectives are to 1) Identify the microbial community members involved in tank biofilms, and if it is a repeated or novel community assembly, and 2) Test for biofilm antagonism in vitro, using competing microorganisms, chemical treatments, and environmental conditions. 

Paper published on animal feed and rumen bacteria

I’m delighted to announce that a paper was published on the effect of a dietary additive on the rumen and fecal bacterial communities in dairy cattle, in the journal Animal: The International Journal of Animal Biosciences!

A lot of factors can be manipulated to help get the most out of one’s diet, including the source and processing method of the ingredients – in most cases in livestock feed: plants. Growing plants for animal feed can be expensive, and often nutrients in plants become more available to the animal after the plant has been processed/broken down in some way. This sometimes allows for food byproducts to be reused for animal feed, and one common example is used brewers’ grains. Once the grains have been fermented to produce alcohol, the simple sugars have been used up but a lot of the complex sugar carbohydrates – in other words: fiber – are left over. Ruminants don’t need simple sugars, but they do need a lot of fiber, and brewers’ grains have been investigated for their usefulness for animal nutrition because they are a cheap, readily-available, and common source of fiber, as well as protein.

The original experiment for this work took place several years ago, and involved an animal feeding trial which added reduced-fat distillers’ grains with solubles into dairy cattle feed. The research team found no negatives effect on milk production or animal health, and that work was previously published. To add to that project, the original research team wanted to know if the diet would drastically change the bacterial community living in the rumen, which would have implications for feed digestion and animal health.

A collaborator of mine donated the cow microbial community DNA data to my AVS 590 special topics in DNA Sequencing Data Analysis course in spring 2020 (now formally registered as AVS 454/554). I worked with UMaine graduate students Adwoa Dankwa and Usha Humagain over the semester to train them in coding and develop the manuscript. The diet only had minimal effects on the bacterial community profiles, which in this case is a good finding – we want to be able to feed a cheap, nutritional source like distillers’ grains without harming the cow or its microbes.


Dankwa, A.S., U. Humagain, S.L. Ishaq, C.J. Yeoman, S. Clark , D.C. Beitz, and E. D. Testroet. 2021. Determination of the microbial community in the rumen and fecal matter of lactating dairy cows fed on reduced-fat dried distillers grains with solubles. Animal 15(7):100281.

Abstract

Reduced-fat dried distillers’ grains with solubles (RF-DDGS) is a co-product of ethanol production and contains less fat than traditional distillers’ grains. The fat in corn is ~ 91% unsaturated, and it is toxic to rumen microorganisms so it could influence the composition of the rumen microbiome. It has been demonstrated that RF-DDGS is a suitable ration ingredient to support the high-producing dairy cow, and this feedstuff is a promising alternative protein source for lactating dairy cows. The current study aims to better understand the effect of RF-DDGS on the rumen and fecal bacterial composition in lactating dairy cows. Thirty-six multiparous (2 or 3), mid-lactation Holstein cows (BW = 680 ± 11 kg; 106 ± 27 DIM) were randomly assigned to two groups which were fed a control diet made up of corn, corn silage, and alfalfa hay supplemented with expeller soybean meal or with added RF-DDGS (20% of the dry matter (DM)) containing approximately 6.0% fat. Whole rumen contents (rumen fluid and digesta; esophageal tubing method) and feces (free catch method) were collected on day 35 of the experimental period, after the 14-d acclimation period. Rumen contents and feces from each cow were used for DNA extraction. The bacterial community composition in rumen and fecal samples was assessed via the 16S rRNA gene by using the Illumina MiSeq sequencing platform. Bacteroidetes, Actinobacteria, and Firmicutes were the most abundant phyla in rumen contents. The fecal microbiota was dominated by the phyla Firmicutes and Bacteroidetes, as well as Actinobacteria and Chloroflexi. RF-DGGS increased bacterial richness, evenness, and Shannon diversity in both rumen and fecal samples and was associated with several taxa that had different abundance in treatment versus control comparisons.  The RF-DGGS, however, did not significantly alter the bacterial community in the rumen or feces. In general, these findings demonstrated that dietary inclusion of RF-DDGS did not impose any serious short-term (within 30 days) health or production consequences, as would be expected. With this study, we present further evidence that inclusion of 20% (DM basis) RF-DDGS in the diet of lactating dairy cows can be done without consequence on the microbiome of the rumen.

Implications

Reduced-fat dried distillers’ grains with solubles is a quality, economical, and readily available protein source demonstrated to support the protein needs of high-producing dairy cows. In this study, the rumen and fecal bacterial communities of lactating dairy cows were not significantly influenced by 20% (dry matter basis) reduced-fat dried distillers’ grains with solubles and did not impose serious short-term (within 30 days) health or production consequences. This diet could potentially be introduced into Total Mixed Ration feeding of dairy cattle given the fact that it is readily available and relatively economical.

Illustrated image of a cross section of the ground. A light brown ant is pictured in the ground along with a microbe. Text to the left of the image reads, "Can a necromenic nematode serve as a biological Trojan horse for an invasive ant?". The names of six professors are listed below the text and image at the bottom left. In the bottom right corner, text reads, "The University of Maine" with "The University of Arizona" below it.

Paper published on bacterial transfer in insects and possible ecological impacts.

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)

Illustrated image of a cross section of the ground. A light brown ant is pictured in the ground along with a microbe. Text to the left of the image reads, "Can a necromenic nematode serve as a biological Trojan horse for an invasive ant?". The names of six professors are listed below the text and image at the bottom left. In the bottom right corner, text reads, "The University of Maine" with "The University of Arizona" below it.

IshaqS.L., A. Hotopp2, S. Silverbrand2, J.E. Dumont, A. Michaud, J. MacRae, S. P. Stock, E. Groden. 2021. Bacterial transfer from Pristionchus entomophagus nematodes to the invasive ant Myrmica rubra and the potential for colony mortality in coastal MaineiScience. In press. Impact 5.08.

Abstract

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. 

Tindall won first prize in a graduate students poster competition!

Congratulations to Tindal Ouverson for winning first prize in the graduate students poster competition at the 2021 Montana State University LRES research colloquium!

Tindall is a master’s of science in Land Resources and Environmental Sciences at Montana State University, working with advisers Drs. Fabian Menalled and Tim Seipel. Tindall and I have been working closely over the past three-ish years on soil microbiomes, and she is preparing to defend her thesis this May.

Check out her recently published paper: Temporal soil bacterial community responses to cropping systems and crop identity in dryland agroecosystems of the Northern Great Plains. 

Tindall’s first paper was accepted!

I’m pleased to announce that master’s student Tindall Ouverson’s first manuscript was accepted for publication!

Photo of woman in front of mountains

Tindall is a Master’s of Science in the Department of Land Resources and Environmental Sciences at Montana State University. Her graduate advisers are Drs. Fabian Menalled and Tim Seipel. Her research focuses on the response of soil microbial communities to cropping systems and climate change in semiarid agriculture. 

I have been mentoring Tindall as a graduate committee member since she began in fall 2019, teaching her laboratory and analytical skills in microbial ecology, DNA sequencing, and bioinformatic analysis. We first met when she came to visit when I was working in Oregon, and since then have connected remotely. She has a flair for bioinformatics analysis, and a passion for sustainable agricultural development. She plans to defend her thesis in 2021, and then to further her career in sustainable agriculture in Montana.


Tindall Ouverson, Jed Eberly, Tim Seipel, Fabian D. Menalled, Suzanne L. Ishaq. 2021. Temporal soil bacterial community responses to cropping systems and crop identity in dryland agroecosystems of the Northern Great Plains.  Frontiers in Sustainable Food Systems.  Article. Invited submission to Plant Growth-Promoting Microorganisms for Sustainable Agricultural Production  special collection.

Abstract

Industrialized agriculture results in simplified landscapes where many of the regulatory ecosystem functions driven by soil biological and physicochemical characteristics have been hampered or replaced with intensive, synthetic inputs. To restore long-term agricultural sustainability and soil health, soil should function as both a resource and a complex ecosystem. In this study, we examined how cropping systems impact soil bacterial community diversity and composition, important indicators of soil ecosystem health. Soils from a representative cropping system in the semi-arid Northern Great Plains were collected in June and August of 2017 from the final phase of a five-year crop rotation managed either with chemical inputs and no-tillage, as a USDA-certified organic tillage system, or as a USDA-certified organic sheep grazing system with reduced tillage intensity. DNA was extracted and sequenced for bacteria community analysis via 16S rRNA gene sequencing. Bacterial richness and diversity decreased in all farming systems from June to August and was lowest in the chemical no-tillage system, while evenness increased over the sampling period. Crop species identity did not affect bacterial richness, diversity, or evenness. Conventional no-till, organic tilled, and organic grazed management systems resulted in dissimilar microbial communities. Overall, cropping systems and seasonal changes had a greater effect on microbial community structure and diversity than crop identity. Future research should assess how the rhizobiome responds to the specific phases of a crop rotation, as differences in bulk soil microbial communities by crop identity were not detectable.

Of mice and many samples

The first mouse study of the Ishaq Lab (in conjunction with the Zhang and Li labs at Husson University) has concluded phase 1, which means that over a few short days, an incredible number of samples needed to be collected, preserved, and processed for further laboratory work (phase 2) which will take through the summer to complete.

Sample collection was made more challenging by the pandemic, because we needed to distance as much as possible, disinfect objects and surfaces, wear masks, and increase the amount of ventilation in a space. Luckily, this type of work lends itself to these types of precautions – not only did we already need to wear a significant amount of protective gear to work with mice or handle their feces, but biosafety work like this requires higher than usual ventilation and frequent sanitation of objects and spaces. Since some of this work could be performed simultaneously in different rooms, we were able to use both Ishaq lab spaces and the ‘mouse house’ to keep people distanced.

During the 40-day mouse study, ‘Team Broccoli’ collected:

  • 640 mouse body weight data measurements
  • 433 fecal samples, which were archived for possible culturing and/or sequencing
  • 400 additional samples collected over two days:
    • 40 blood samples for immune factor identification
    • 360 gut samples
      • Of which, 200 were PMA treated within 12 hours of collection for use in DNA sequencing
      • 160 of which will be cultured to isolate bacteria. This will create 1 ~ 8 isolates per sample that will need to be grown on its own plate, transferred to broth media, and then frozen with glycerol at -80C until they can be revived and studied later this year.

Emily awarded an undergraduate research fellowship!

The very first Ishaq Lab undergraduate researcher, Emily Pierce, has also been awarded the first fellowship of the Ishaq Lab!

Emily has been awarded a Faculty Fellows Research Assistantship for spring 2021 from the University of Maine Center for Undergraduate Research (CUGR)! The $1200 award will provide funds for salary to Emily and research materials, and will support her project for her AVS Capstone Experience (selected Capstone project summaries are here, but Emily’s is not included).

Portrait of Emily Pierce

Emily joined the lab in early 2020 to work on a project investigating calf health and gut microbes, but very soon after joining the lab, the SARS-CoV-2 pandemic emerged and changed the way we were able to interact on campus. Without missing a beat, Emily shifted her efforts from helping me wrangle the lab renovations and sorting out our inventory, to helping me improve my teaching materials, to diving deep into previous literature to dig up protocols for her experiment in 2021: “Ideal Conditions for Cryptosporidium Attachment and Infection.

We’ll be performing the experiment itself over the winter break, and then using the spring to analyze the data and write them up. As part of the CUGR award, Emily will be presenting her work at the 2021 Student Symposium in April, which will be held virtually this year. You’ll have to wait till then to get more details!