Sex and age specific infestation rates of raccoons (Procyon lotor) by American dog ticks (Dermacentor variabilis)

Abstract only availableAmerican dog ticks (Dermacentor variabilis) can have profound direct and indirect effects on human and wildlife hosts. However, there is little information on their short- or long-term rates of parasitism in free-ranging wildlife populations. In Missouri, raccoons (Procyon lotor) are the principal host of dog ticks, with tick prevalence reaching up to 90%. Our goal was to determine the intensity of non-engorged (short-term) and engorged (long-term) tick infestations among different age, sex, and reproductive classes of raccoons. From May to July 2005 we captured 105 raccoons across eight populations residing in predominantly forested ecosystems of central Missouri. Raccoons were sexed, weighed, and aged by examining tooth wear, genital morphology, and body size. Ticks were sampled by direct, two-minute timed observations to estimate tick abundance. Non-engorged and engorged ticks infested males, lactating females, and non-lactating females in decreasing levels of intensity. There was no correlation between weight and the intensity of tick infestation, but tick burdens generally increased with age.Life Sciences Undergraduate Research Opportunity Progra

Combinatorial Pharyngeal Taste Coding for Feeding Avoidance in Adult Drosophila.

Taste drives appropriate food preference and intake. In Drosophila, taste neurons are housed in both external and internal organs, but the latter have been relatively underexplored. Here, we report that Poxn mutants with a minimal taste system of pharyngeal neurons can avoid many aversive tastants, including bitter compounds, acid, and salt, suggesting that pharyngeal taste is sufficient for rejecting intake of aversive compounds. Optogenetic activation of selected pharyngeal bitter neurons during feeding events elicits changes in feeding parameters that can suppress intake. Functional dissection experiments indicate that multiple classes of pharyngeal neurons are involved in achieving behavioral avoidance, by virtue of being inhibited or activated by aversive tastants. Tracing second-order pharyngeal circuits reveals two main relay centers for processing pharyngeal taste inputs. Together, our results suggest that the pharynx can control the ingestion of harmful compounds by integrating taste input from different classes of pharyngeal neurons

The influence of increased contact rate among raccoons on a nematode of public, and wildlife health concern, Baylisascar [abstract]

Abstract only availableNatural and anthropogenic fluctuations in resource availability can alter the behavioral ecology and population dynamics of wildlife. This may have unintended consequences to wildlife disease ecology, as theoretical models predict parasite transmission is highly dependent on contact rate and density of individuals within a population. We examined the influence of alterations in the behavioral ecology of hosts on the nematode Baylisascaris procyonis of raccoons, that can infect and cause disease and mortality in a variety of animals, including humans. Twelve populations of free-ranging raccoons were monitored for three years. After one year of baseline data collection, we experimentally altered the contact rate and resource availability of randomly selected populations via dispersed or clumped food distributions. Rates of contact were measured via remote cameras and host characteristics (age, sex) and infection of B. procyonis in individuals were assessed via live-capture and standard sugar flotation techniques. Prevalence of B. procyonis averaged 6.5% at three control sites (no food added; n=186 individuals), 14.3% at four sites had dispersed food additions (n=42), and 21% at five sites with clumped food additions that aggregated raccoons (n=81). The 95% confidence interval of prevalence at experimental sites did not overlap with values observed at control sites. Data collected prior to manipulation indicated that differences observed during the experiment were not due to naturally occurring differences at those sites; prevalence of B. procyonis averaged 2.3% at sites assigned to the control category, 5.4% at sites assigned to the dispersed food category, and 4.1% at sites assigned to the experimental category. These results support the hypothesis that increased rates of contact can increase transmission of parasites such as B. procyonis, and emphasize the potentially important role of anthropogenic activity in wildlife disease ecology when dealing with species that can take advantage of such resources and tolerate aggregations of conspecifics.NSF Undergraduate Mentoring in Environmental Biolog

The influence of increased contact rate among raccoons on a directly transmitted nematode, Baylisascaris procyonis [abstract]

Abstract only availableHuman encroachment on wildlife habitat can result in anthropogenic food sources that aggregate raccoons. This may have unintended consequences to wildlife and human health, as theoretical models predict parasite transmission is highly dependent on the contact rate and density of individuals within a population. We examined the influence of contact rate on a directly transmitted nematode (Baylisascaris procyonis) of raccoons that can infect and cause disease and mortality in a wide range of accidental hosts, including humans. Twelve populations of free-ranging raccoons were monitored for three years. After one year of baseline data collection, we experimentally altered the contact rate and resource availability of randomly selected populations via dispersed or clumped food distributions. Prior to manipulation, prevalence of B. procyonis averaged 9% across all sites (range 0-35%). During the experiment, prevalence of B. procyonis averaged 4% at control sites (no food added), 18% at sites that had dispersed food additions (which did not increase contact), and 22% at sites with clumped food additions that aggregated raccoons. Data collected prior to the experiment indicated that sites that were assigned to the dispersed food treatment had a naturally-occurring higher prevalence (13%) than the sites assigned to the control (5%) and aggregation treatment (9%), indicating that the high values observed in the dispersed food sites during the experiment may be due to site-specific differences rather than the addition of dispersed food. These results support the hypothesis that increased rates of contact can increase transmission of directly transmitted parasites such as B. procyonis, and emphasize the potentially important role of anthropogenic activity in the ecology of diseases when dealing with wildlife species that can take advantage of such resources and tolerate large aggregations of conspecifics

The effect of genetic relatedness and diversity on parasite load in the North American raccoon (procyon lotor) [abstract]

Abstract only availableThe influence of genetic relatedness and diversity on parasite transmission and diversity was examined in raccoons (Procyon lotor) from mid-Missouri. Relatedness and diversity of individuals was measured using 12 polymorphic microsatellite loci that were amplified using the polymerase chain reaction (PCR). Fragment analysis was used to determine the alleles of the individuals at each locus. Using the computer analysis program Kinship, relationship probabilities were calculated between individuals and populations. Heterozygosity, internal relatedness, and d2 values were also calculated. Parasite similarity indices did not differ among pairwise comparisons of animals with first order, second order, and no detected relationships. We are currently investigating if correlations exist between ectoparasite or endoparasite loads and heterozygosity, internal relatedness and d2 values. The data generated in this preliminary study will be used in a larger study of patterns of disease/parasite occurrences in artificially aggregating raccoons.Life Sciences Undergraduate Research Opportunity Progra

Genetic relatedness of artificially aggregating raccoons (Procyon lotor) [abstract]

Abstract only availableFaculty Mentor: Lori Eggert, Biological SciencesRaccoons are generally solitary animals but due to increasing human populations, solitary animals such as the raccoon are forced into closer contact with one another. Aggregation in general may result in the transmission of diseases and parasites, but it is unclear whether the transmission is due solely to aggregation or if genetic relatedness plays a role in disease/parasite transmission.  My project examined the relatedness between raccoons aggregating at enriched food sources at several local field sites. To determine relatedness between individuals, I amplified twelve polymorphic microsatellite loci using polymerase chain reaction (PCR). Fragment analysis will then be used to determine the alleles of the individuals at each locus. Using the computer analysis program Kinship, relationship probabilities will be calculated between individuals and populations. The data generated in this study will be used in a larger study of patterns of disease/parasite occurrences in aggregating raccoons

Myeloma cells down‐regulate adiponectin in bone marrow adipocytes via TNF‐alpha

Multiple myeloma is caused by abnormal plasma cells that accumulate in the bone marrow and interact with resident cells of the bone microenvironment to drive disease progression and development of an osteolytic bone disease. Bone marrow adipocytes (BMAds) are emerging as having important endocrine functions that can support myeloma cell growth and survival. However, how BMAds respond to infiltrating tumor cells remains poorly understood. Using the C57BL/KaLwRij murine model of myeloma, bone marrow adiposity was found to be increased in early stage myeloma with BMAds localizing along the tumor‐bone interface at later stages of disease. Myeloma cells were found to uptake BMAd‐derived lipids in vitro and in vivo, although lipid uptake was not associated with the ability of BMAds to promote myeloma cell growth and survival. However, BMAd‐derived factors were found to increase myeloma cell migration, viability, and the evasion of apoptosis. BMAds are a major source of adiponectin, which is known to be myeloma‐suppressive. Myeloma cells were found to downregulate adiponectin specifically in a model of BMAds but not in white adipocytes. The ability of myeloma cells to downregulate adiponectin was dependent at least in part on TNF‐α. Collectively our data support the link between increased bone marrow adiposity and myeloma progression. By demonstrating how TNF‐α downregulates BMAd‐derived adiponectin, we reveal a new mechanism by which myeloma cells alter the bone microenvironment to support disease progression. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research