Biology subjects

Mitchell, M. M.

Publications and source records attributed to Mitchell, M. M..

3 recordsLinked to original sources

bioRxiv2024

Undergraduate research project uncovers a novel strain of amphibian chytrid fungus in the Northeastern United States

Investigation of the genetic variation of Batrachochytrium dendrobatidis (Bd or chytrid fungus) in New Hampshire (NH) in the northeastern U.S. has shown the presence of genetic mutations which are currently undocumented in the literature. DNA was collected as part of a long-term monitoring project in New Hampshire to test for the presence of Bd in amphibian populations. In this monitoring project, we are detecting the presence of Bd in multiple populations, but the observed amphibians do not appear to have increased mortality or other symptoms related to the fungus. To further investigate the strain of Bd affecting NH amphibians, we sequenced samples that were collected in 2019, as part of your yearly monitoring effort. Utilizing the Basic Local Alignment Search Tool (BLAST) and sequences available on GenBank, we found that there are two different strains of chytrid in the observed NH amphibians. These strains are similar to strains noted previously in New England, but exhibit unique point mutations and in one case, a deletion. These variations could affect the impact that Bd has on amphibians in this region, and therefore could contribute to a better understanding of the variation in strains of chytrid and how they impact amphibian populations around the world. This study highlights the importance of monitoring efforts conducted at smaller, non-research institutions and we encourage other small institutions to take up similar monitoring efforts for Bd or other national or global conservation concerns.

ecology↗

bioRxiv2021

Living Shorelines Achieve Functional Equivalence to Natural Fringe Marshes across Multiple Ecological Metrics

Nature-based features provide a welcome class of adaptations to promote ecological resilience in the face of climate change. Along coastlines, living shorelines are among the preferred adaptation strategies to both reduce erosion and provide ecological functions. As an alternative to shoreline armoring, living shorelines are viewed favorably among coastal managers, wetlands boards, and some private property owners, but they have yet to undergo a thorough examination of how their levels of ecosystem functions compare to their closest natural counterpart: fringing marshes. Here, we provide a synthesis of results from a multi-year, large-spatial-scale study in which we compared numerous ecological metrics measured in thirteen pairs of living shorelines and natural fringing marshes throughout coastal Virginia, USA. Overall, we found that living shorelines were functionally equivalent to natural marshes in nearly all measured aspects, except for a lag in sediment composition. These data support the prioritization of living shorelines as a coastal adaptation strategy.

ecology↗

bioRxiv2020

Financial strain and stressful social environment drive depressive symptoms, while FKBP5 variant intensifies the effect, in African Americans living in Tallahassee

The World Health Organization estimates that almost 300 million people suffer from depression worldwide. Depression is the most common mental health disorder and shows racial disparities in disease prevalence, age of onset, severity of symptoms, frequency of diagnosis, and treatment utilization across the United States. Since depression has both social and genetic risk factors, we propose a conceptual model wherein social stressors are primary risk factors for depression, but genetic variants increase or decrease individual susceptibility to the effects of the social stressors. Our research strategy incorporates both social and genetic data to investigate variation in symptoms of depression (CES-D scores). We collected data on financial strain (difficulty paying bills) and personal social networks (a model of an individuals social environment), and we genotyped genetic variants in five genes involved in stress reactivity (HTR1a, BDNF, GNB3, SLC6A4, and FKBP5) in 135 African Americans residing in Tallahassee, Florida. We found that high financial strain and a high percentage of people in ones social network who are a source of stress or worry were significantly associated with higher CES-D scores and explained more variation in CES-D scores than did genetic factors. Only one genetic variant (rs1360780 in FKBP5) was significantly associated with CES-D scores and only when the social stressors were included in the model. Interestingly, the effect of FKPB5 appeared to be strongest in individuals with high financial strain such that participants with a T allele at rs1360780 in FKBP5 and high financial strain had the highest mean CES-D scores in our study population. These results suggest that material disadvantage and a stressful social environment increases the risk of depression, but that individual-level genetic variation may increase susceptibility to the adverse health consequences of social stressors.

genetics↗