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!

A very close-up image of a small, dark brown mouse perched on the arm of a graduate researcher wearing a surgical gown.

The first mouse study involving the Ishaq Lab begins!

Mice have arrived for a collaborative project on diet, gut microbes, and health in conjunction with researchers at Husson University! This is the first mouse project for the Ishaq Lab, and also my first hands-on mouse project (in my previous publications with mice, I received datasets but the mouse work was performed solely by my collaborators).

This is one of my first new collaborations at the University of Maine, which began in September 2019 as I was just finding my way around campus. An established researcher at Husson University, Dr. Yanyan Li, reached out to welcome me and talk about overlap between our work. Yanyan, her husband Dr. Tao Zhang, also a researcher at Husson University, and collaborator Dr. Grace Chen at Michigan State University, had been working on beneficial compounds found in broccoli using mice as an experimental model for Inflammatory Bowel Disease (IBD). Over the past year, in consultation with IBD experts Drs. Gary Mawe and Peter Moses (who I worked with previously while at UVM!), we have written several proposals for funding to expand the project.

Johanna Holman worked for several years with Yanyan and Tao, as an undergraduate researcher and then as a research assistant. She joined the Ishaq Lab this fall to continue her work as a graduate student and add gut microbiology to her skill repertoire. This experiment will form the base of her graduate thesis, and Johanna is taking a lead role in managing the project as well as several undergraduate researchers, including Dorien Baudewyns, assisting with the mice and lab work. As an early career researcher, and new to mice, I’m extremely lucky to be able to learn from an experienced team of researchers!

An image of a microbiology and genetics laboratory.

Establishing a research laboratory

As a new assistant professor at the University of Maine, 50% of my appointment is research. To establish my research, I started with curating a space to fulfill the needs of my work — “professional nesting”, if you will. I was allotted two adjacent rooms for my lab work, one as a microbial culturing space, and one for genomics work. I asked for and was granted separate spaces to reduce to likelihood of contamination sourced from my culturing space.

Prior to my arrival at the University of Maine, both lab spaces were set up to perform different research from what I do. This may not seem like it would interfere with my work, but the type of research you do will influence the machinery you need, each of which may have space or utilities requirements, as well as the flow of traffic through the room. To reduce the amount of time you spend moving around the room in search of elusive supplies, it’s best to curate work stations within the room. To that end, the Ishaq lab team spent several days re-arranging the large machinery and the table-top equipment, and then moving the supplies to the cabinets in corresponding locations. This change was most evident in the genomics room, that was previously used for human cell culture and biochemistry, shown below. At this time, I’m still working on updating the microbial culture room, which is larger and contained many more bits and pieces to organize.

  • An image of a microbiology and genetics laboratory.

Most research labs use extremely specialized equipment and machinery. Some of this was made available to me immediately; when research labs are discontinued, ownership of equipment and consumable materials reverts back to the researcher’s home department. I needed to purchase some of the more research-specific equipment, using some of the funds allotted to me for this purpose. Buying equipment can be stressful, because it can be incredibly expensive, and you want to be sure you selected the machine brand and range of capabilities for what you might want to do over the next 5 – 10 years, at least.

Finally, you need to stock your lab with reagents and researchers, but both of these have been temporarily put on hold as of March 2020, as we do our part to reduce the transmission of the Covid-19 virus. Whenever it is safe to do so, I look forward to completing the updates to my spaces and opening them up for collaborative work.

Wild blueberries on a bush.

My first funded proposal at UMaine!

Now that I’m an assistant professor, a significant amount of my time is spent writing grant proposals to fund projects I’d like to do in the future.

Many large federal or foundational grants take up to a year from submission to funds distribution, and the success rate, especially for newly-established researches, can be quite low. It’s prudent to start writing well in advance of the due date, and to start small, with “pilot projects”.

To that end, I’m pleased to announce that Dr. Lily Calderwood and I just received word that the Wild Blueberry Commission of Maine is funding a pilot project of ours; “Exploration of Soil Microbiota in Wild Blueberry Soils“. We’ll be recruiting 1 – 2 UMaine students for summer/fall 2020 to participate in the research for their Capstone senior research projects.

Dr. Calderwood is an Extension Wild Blueberry Specialist, and Assistant Professor of Horticulture in the School of Food and Agriculture at UMaine. She and I developed this project when meeting for the first time, over coffee. We realized we’d both been at the University of Vermont doing our PhD’s concurrently, and in neighboring buildings! We got to chatting about my work in wheat soil microbial communities, and her work on blueberry production, and the untapped research potential between the two.

This pilot will generate some preliminary data to help us get a first look at the soil microbiota associated with blueberries, and in response to management practices and environmental conditions. From this seed funding, Lily and I hope to cultivate fruitful research projects for years to come!

Featured Image: Wild Maine Blueberries, Wikimedia

Microbes and Social Equity essay published!

I’m pleased to announced that the ‘microbes and social equity’ paper has been published as an essay in PLoS Biology, and will be included in their Microbiomes Across Biological Systems special issue.

In summer 2019, I developed and taught a course on ‘Microbes and Social Equity‘ to the Clark Honors College at the University of Oregon. The course assignments were literature review essays on various topics, which were compiled into a single manuscript as the group-based final project for the course. This large version is available as a preprint; however, the published version is more focused.


Framing the discussion of microorganisms as a facet of social equity in human health.

Suzanne L. Ishaq1,2*, Maurisa Rapp2,3, Risa Byerly2,3, Loretta S. McClellan2, Maya R. O’Boyle2, Anika Nykanen2, Patrick J. Fuller2,4, Calvin Aas2, Jude M. Stone2, Sean Killpatrick2,4, Manami M. Uptegrove2, Alex Vischer2, Hannah Wolf2, Fiona Smallman2, Houston Eymann2,5, Simon Narode2, Ellee Stapleton6, Camille C. Cioffi7, Hannah Tavalire8

  1. Biology and the Built Environment Center,  University of Oregon
  2. Robert D. Clark Honors College, University of Oregon
  3. Department of Human Physiology, University of Oregon
  4. Charles H. Lundquist College of Business, University of Oregon
  5. School of Journalism and Communication, University of Oregon
  6. Department of Landscape Architecture, University of Oregon
  7. Counseling Psychology and Human Services, College of Education, University of Oregon
  8. Institute of Ecology and Evolution, University of Oregon

Abstract

What do ‘microbes’ have to do with social equity? On the surface, very little. But these little organisms are integral to our health, the health of our natural environment, and even impact the ‘health’ of the environments we have built. Early life and the maturation of the immune system, our diet and lifestyle, and the quality of our surrounding environment can all impact our health. Similarly, the loss, gain, and retention of microorganisms ⁠— namely their flow from humans to the environment and back⁠ — can greatly impact our health and well-being. It is well-known that inequalities in access to perinatal care, healthy foods and fiber, a safe and clean home, and to the natural environment can create and arise from social inequality. Here, we focus on the argument that access to microorganisms as a facet of public health, and argue that health inequality may be compounded by inequitable microbial exposure.

Paper published on effect of farming systems on soil bacteria!

After several years of bouncing through internal and external review, I’m pleased to announce that the first microbes paper out of the Montana State University Fort Ellis project has been published in Geoderma! The Fort Ellis research has encompassed multiple labs, projects, and many personnel, as it was a large collaboration looking at the effect of different farming systems on biodiversity at the macro (plant), mini (insect), and micro (-be) levels. Spanning multiple years, this project has been a massive undertaking that I briefly participated in but anticipate getting four publications out of (two more are in preparation).

Winter wheat

I previously presented this work at the 2017 Ecological Society of America (ESA) conference (poster: Ishaq et al ESA 2017 poster). And this field soil was the “soil probiotic” that was used in the follow-up greenhouse trial that I ran which was also published this year.


Soil bacterial communities of wheat vary across the growing season and among dryland farming systems.

Ishaq, S.L., Seipel, T., Yeoman, C.J., Menalled, F.D. 2020. Geoderma 358:113989.

Abstract

Despite knowledge that management practices, seasonality, and plant phenology impact soil microbiota; farming system effects on soil microbiota are not often evaluated across the growing season.  We assessed the bacterial diversity in soil around wheat roots through the spring and summer of 2016 in winter wheat (Triticum aestivium L.) in Montana, USA, from three contrasting farming systems: a chemically-managed no-tillage system, and two USDA-certified organic systems in their fourth year, one including tillage and one where sheep grazing partially offsets tillage frequency. Bacterial richness (range 605 – 1174 OTUs) and evenness (range 0.80 – 0.92) peaked in early June and dropped by late July (range 92 – 1190, 0.62-0.92, respectively), but was not different by farming systems.  Organic tilled plots contained more putative nitrogen-fixing bacterial genera than the other two systems.  Bacterial community similarities were significantly altered by sampling date, minimum and maximum temperature at sampling, bacterial abundance at date of sampling, total weed richness, and coverage of Taraxacum officinale, Lamium ampleuxicaule, and Thlaspi arvense.  This study highlights that weed diversity, season, and farming management system all influence soil microbial communities. Local environmental conditions will strongly condition any practical applications aimed at improving soil diversity, especially in semi-arid regions where abiotic stress and seasonal variability in temperature and water availability drive primary production. Thus, it is critical to incorporate or address seasonality in soil sampling for microbial diversity.