In the Lit: High-dose saccharin supplementation does not induce gut microbiota changes or glucose intolerance in healthy humans and mice

Non-caloric artificial sweeteners (NCAS) are widely used as a substitute for dietary sugars to control body weight or glycemia. Paradoxically, some interventional studies in humans and rodents have shown unfavorable changes in glucose homeostasis in response to NCAS consumption. The causative mechanisms are largely unknown, but adverse changes in gut microbiota have been proposed to mediate these effects. These findings have raised concerns about NCAS safety and called into question their broad use, but further physiological and dietary considerations must be first addressed before these results are generalized. We also reasoned that, since NCAS are bona fide ligands for sweet taste receptors (STRs) expressed in the intestine, some metabolic effects associated with NCAS use could be attributed to a common mechanism involving the host.

https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-020-00976-w

Serrano J, Smith KR, Crouch AL, Sharma V, Yi F, Vargova V, LaMoia TE, Dupont LM, Serna V, Tang F, Gomes-Dias L, Blakeslee JJ, Hatzakis E, Peterson SN, Anderson M, Pratley RE, Kyriazis GA. High-dose saccharin supplementation does not induce gut microbiota changes or glucose intolerance in healthy humans and mice. Microbiome. 2021 Jan 12;9(1):11. doi: 10.1186/s40168-020-00976-w. PMID: 33431052; PMCID: PMC7802287.

Postdoctoral Researcher position open

The Anderson lab is seeking a Postdoctoral Researcher to join our team. Applicants to this position will be working as part of a collaborative project to determine how evolution acts on function of individual paralogs in a human fungal pathogen Candida albicans gene family. This work will require an understanding of general genetic and evolutionary concepts but applicants with diverse perspectives covering a range of biological approaches including genetics and genomics, evolutionary biology, molecular biology, cell biology, microbiology, and bioinformatics that hold a Ph.D. in a biological/biomedical field are encouraged to apply. Basic molecular biology skills will be required and applicants will ideally be situated to enter with some experience in bioinformatics or large dataset analysis. Willingness to learn these approaches including mastery of scripting languages (Python or R) will be required. This position is seeking an individual for a minimum of a three year time commitment and may continue for longer periods. Please explore this site for a more complete description of our research group.

We highly encourage applicants from underrepresented groups to apply. Our group holds up the importance of diverse life experiences and viewpoints to strengthen the whole of our group.

Welcoming our first Postdoctoral Scholar

We are very excited to welcome Dr. Abhishek Mishra to the lab as our first postdoctoral scholar. Abhishek joins us from the Indian Institute of Science Education and Research (IISER) Pune, where he conducted his work in the Population Biology Laboratory led by Dr. Sutirth Dey. There, Abhishek published substantially on work aiming to define dispersal ecology and evolution and how it shapes population dynamics, biological invasions, range expansions, and community assembly. Abhishek joins the lab having been awarded funding support from The Ohio State University President’s Postdoctoral Scholars Program. Welcome!

Abhishek Mishra


mishra.266@osu.edu
Pathogenesis in C. albicans using quantitative genetics, transcriptional networking, and experimental evolution.
Position:
Postdoctoral Scholar
Degree:
PhD and Integrated BS-MS (IISER Pune, India)

Award Announcement – Career 2046863 to Dr. Matthew Anderson

Dr. Matthew Anderson was recently awarded NSF Career 2046863 for the work entitled “Paralog function following rapid gene family expansion in Candida albicans.”

This project seeks to determine how multiple genes that all arose recently from a single gene establish their function when other copies of that gene are present. Nearly all genes in every organism on the planet arose from previously existing genes and not from DNA that lacked function. As this process repeats, a large set of highly similar genes can form a gene family that often give an organism certain advantages in adapting to its specific lifestyle. For example, yeasts used in brewing have expanded gene families for fermentation and humans have expanded genes for being able to distinguish between good and rotten food. A gene family in the human fungal pathogen Candida albicans called the telomere-associated (TLO) gene family has expanded from 1 to 14 copies and is an ideal system to test how functions of individual members of gene families are shaped by the presence of many genetically and functionally similar genes. This project will generate large datasets and highlights the needs for people to be trained in analysis. This project will therefore also train Indigenous students in bioinformatics through a summer workshop to promote data sovereignty and Indigenous research capacity.

This project will begin to address the concept of Ohno’s Dilemma in a large gene family, how function evolves when multiple other similar genes are present. We will use the TLO genes from C. albicans to find how each gene holds individual or overlapping functions with other genes in the gene family. Molecular and organismal functions will be determined for these genes using strains missing single genes of the gene family and strains lacking all TLO genes except for one. Strains lacking single genes will define the amount of overlap in gene functions, and strains containing single genes will determine the range of function for each gene.

This award reflects NSF’s statutory mission and has been deemed worthy of support through evaluation using the Foundation’s intellectual merit and broader impacts review criteria.

https://www.nsf.gov/awardsearch/showAward?AWD_ID=2046863&HistoricalAwards=false

In the Lit: High-dose saccharin supplementation does not induce gut microbiota changes or glucose intolerance in healthy humans and mice

Non-caloric artificial sweeteners (NCAS) are widely used as a substitute for dietary sugars to control body weight or glycemia. Paradoxically, some interventional studies in humans and rodents have shown unfavorable changes in glucose homeostasis in response to NCAS consumption. The causative mechanisms are largely unknown, but adverse changes in gut microbiota have been proposed to mediate these effects. These findings have raised concerns about NCAS safety and called into question their broad use, but further physiological and dietary considerations must be first addressed before these results are generalized. We also reasoned that, since NCAS are bona fide ligands for sweet taste receptors (STRs) expressed in the intestine, some metabolic effects associated with NCAS use could be attributed to a common mechanism involving the host.

https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-020-00976-w

Winter 2020

With big snowflakes falling we wanted to take a moment and acknowledge Emily Simonton who rotated with us in the second round. Emily is a Columbus local, receiving her undergraduate degree from Capital University just down the road. They spent their rotation working mainly with Audra Crouch on eukaryome extraction optimization but also explored some new work with SARS-CoV-2 positive patient samples. Thanks for rotating with us!

Emily Simonton

Optimizing the protocol for eukaryote DNA extraction from stool samples and analyzing RNAseq reads from SARS-CoV-2 patients
Position:
Rotation Student
Degree:
Capital University, B.A. in Biology with a minor in Criminology

The End of the First 2020 Rotation

As the first round of rotations for the year comes to a close, we wanted to share that John Van Dusen from the Department of Microbiology has been working with Audra on the eukaryome work. Thanks for rotating with us, John!

John Van Dusen

Extracting and Purifying DNA from Oral Samples for the Eukaryome Project.
Position:
Rotation Student
Degree:
Loyola University Chicago, BS in Biology

In the Lit: Automated quantification of Candida albicans biofilm-related phenotypes reveals additive contributions to biofilm production

Biofilms are organized communities of microbial cells that promote persistence among bacterial and fungal species. Biofilm formation by host-associated Candida species of fungi occurs on both tissue surfaces and implanted devices, contributing to host colonization and disease. In C. albicans, biofilms are built sequentially by adherence of yeast to a surface, invasion into the substrate, the formation of aerial hyphal projections, and the secretion of extracellular matrix. Measurement of these biofilm-related phenotypes remains highly qualitative and often subjective. Here, we designed an informatics pipeline for quantifying filamentation, adhesion, and invasion of Candida species on solid agar media and utilized this approach to determine the importance of these component phenotypes to C. albicans biofilm production. Characterization of 23 C. albicans clinical isolates across three media and two temperatures revealed a wide range of phenotypic responses among isolates in any single condition. Media profoundly altered all biofilm-related phenotypes among these isolates, whereas temperature minimally impacted these traits. Importantly, the extent of biofilm formation correlated significantly with the additive score for its component phenotypes under some conditions, experimentally linking the strength of each component to biofilm mass. In addition, the response of the genome reference strain, SC5314, across these conditions was an extreme outlier compared to all other strains, suggesting it may not be representative of the species. Taken together, development of a high-throughput, unbiased approach to quantifying Candida biofilm-related phenotypes linked variability in these phenotypes to biofilm production and can facilitate genetic dissection of these critical processes to pathogenesis in the host.

https://www.nature.com/articles/s41522-020-00149-5

Welcome to Dr. Paula Sundstrom

We are very excited to formally welcome Dr. Paula Sundstrom to the lab as she conducts her research here in the Riffe building as an Adjunct Professor. Her insight and research experience has already started driving new projects and ideas. Welcome Paula!

“I seek to address basic questions about interactions between Candida albicans and human hosts that enable commensal and pathogenic states. The approaches include experimental evolution, genomics, bioinformatics and murine animal models to understand processes such as C. albicans’ gene expression in the host, diversity and host immune responses that contribute to both protection and damage.”

Paula Sundstrom


sundstrom.1@osu.edu
Candida albicans commensal and pathogenic states. Experimental evolution, genomics, bioinformatics and murine animal models.
Position:
Adjunct Professor
Degrees:
Pomona College, Claremont, CA (B.A.)
University of Washington, Seattle (Ph.D.)

A Start to a New Semester

While adapting to the new normal, we are very excited to share that Leah Anderson has been accepted into the University of Washington Genome Sciences program. We wish her best!

We welcome Anna Mackey into the lab as the new lab manager, working on identifying gut microbiome diversity, and Amber Anger from MCDB who will be rotating with a TLO based project.

Anna Mackey


mackey.201@osu.edu
Investigating gut microbiome diversity, specifically focusing on the eukaryome, along urbanization and industrialization gradients.
Position:
Lab Technician
Degree:
The Ohio State University, BS Mathematical Biology

Amber Anger


anger.4@osu.edu
Create KO strains for each of the TLO genes, examine the resulting mutant phenotypes, and use bioinformatics to characterize the TLO gene family.
Position:
Rotation Student
Degree:
University of Michigan, B.S. in Molecular Biology & Central Michigan, M.Sc. in Biochemistry, Cell, & Molecular Biology