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Many amphibian species worldwide have exhibited significant population declines due to exposure to the emerging infectious disease (EID), Batrachochytrium dendrobatidis. Previous PCR analyses revealed the presence of this fungus in species of Mannophyrne trinitatis sampled in Trinidad and Tobago in 2007. Tadpoles of Bufo marinus collected in Trinidad in 2003 were examined for the presence of chytrid infection. In all, we examined 645 tadpoles of 13Gosner developmental stages (29-42) for morphological anomalies commonly associated with chytrid infection. Oral deformities were common in this sample. The number of deformities ranged from 0 (in Gosner 29, 30 and 42) up to 83 percent (in Gosner 37), with most stages showing greater than 50% with abnormalities. Patterns exhibited show that the number of deformities increased as the development proceeded (from Gosner 29 - 41). These data also show that the posterior mouthparts of infected tissues are more likely to be deformed than non-infected. Comparable data from the literature show that B. marinus is more susceptible to the infection than species of the anuran families Ranidae and Hylidae. Histological examinations of oral tissues confirmed the presence of chytrid infection in this sample. This work pushes the time of appearance of the chytrid fungus on Trinidad back to at least 2003.
Sin Nombre virus (SNV) causes hantavirus pulmonary syndrome (HPS) in humans, a disease with high (∼36%) mortality. Deer mice (Peromyscus maniculatus) are the primary host of SNV and, unlike humans, deer mice infected with SNV have few overt signs of disease. The reasons for such mild infections in deer mice have not been well studied; however, this information may be useful in uncovering therapies that could reduce human HPS mortality. Therefore, the objective of this study was to evaluate the immune response of deer mice to SNV by examining their patterns of white blood cell production. We quantified the number of lymphocytes, eosinophils, basophils, neutrophils, and monocytes produced by wild deer mice in both the early and late stages of SNV infection. Deer mice captured in the early season had greater basophil, lymphocyte, and eosinophil levels compared to deer mice captured in the late season. Conversely, monocyte levels were greater in deer mice captured in the late season. SNV infection status appeared to influence production of both neutrophils and monocytes, with SNV-infected mice having greater neutrophil levels but lower monocyte levels than uninfected mice. Collectively, the results seem to support the notion that immune stressors faced by wild deer mice shift from early to late season, and these differences are reflected by differential leukocyte production that occurs across seasons. Furthermore, our results indicate some potential differences between wild deer mice and lab-bred deer mice, as well as some possible similarities between wild deer mice and humans in their immune responses to SNV infection.
With increased interest in biofuel production, the conversion of agricultural lands (known to concentrate salts) as well as other marginal lands will be critical in establishing a switchgrass-based renewable biofuel industry. In this study three cultivars (Trailblazer, Cave-in-Rock, and Blackwell) of Panicum virgatum (switchgrass) were germinated in a NaCl gradient of 0.0, 0.0504, 0.1002, and 0.1546 molar solutions. Three replicates were run, lasting 20 days each, from September 2010 to November 2010. Each replicate consisted of six samples for each cultivar:concentration combination, for a total of 72 samples per replicate. A two-way ANOVA indicated that for all three replicates percent germination was significantly affected by salinity concentration, cultivar type, and salinity concentration x cultivar type (p<0.05). Furthermore, post hoc results showed that nearly every combination of cultivars and concentrations with respect to percent germination was significant. In all, the data from all three replicates showed that the Trailblazer cultivar was the most successful at germinating in saline conditions for every concentration tested. This information fills a crucial gap in knowledge, as most research pertaining to switchgrass has focused on conversion of plant matter into alcohols from sugars as well as cellulose. From this study, decisions regarding cultivar type and alterations to standard seeding density, based upon germination rates, may be determined to make land conversion as economically and ecologically productive as possible.
Operating under several assumptions regarding density-dependant dispersal, a novel way of visualizing the source-sink dynamics of metapopulations is introduced in which vector calculus operators were applied to approximated surface functions. First, occurrence data were used to create a population density matrix for a fictional Genus species, which was modeled as a 3-dimensional scatter plot. Next, the data were fitted to an approximated function corresponding to the data's 3-dimensional surface, permitting the data to be treated as a scalar field. This scalar field was then subjected to the gradient and divergence operators to produce a mathematical model of G. species migration and source-sink dynamics, respectively.
The following chapters have sent in officer slates for 2012-2013. Officers are listed in the order of President, Vice President, Secretary, Treasurer, Historian, and Faculty Advisor unless otherwise noted. The chapters are listed alphabetically by Greek name. Please submit new slates, changes and corrections to Lori.Kelman@montgomerycollege.edu.