Temporal and Environmental Factors Driving Vibrio Vulnificus and V. Parahaemolyticus Populations and Their Associations With Harmful Algal Blooms in South Carolina Detention Ponds and Receiving Tidal Creeks.

Incidences of harmful algal blooms (HABs) and Vibrio infections have increased over recent decades. Numerous studies have tried to identify environmental factors driving HABs and pathogenic Vibrio populations separately. Few have considered the two simultaneously, though emerging evidence suggests that algal blooms enhance Vibrio growth and survival. This study examined various physical, nutrient, and temporal factors associated with incidences of HABs, V. vulnificus, and V. parahaemolyticus in South Carolina coastal stormwater detention ponds, managed systems where HABs often proliferate, and their receiving tidal creek waters. Five blooms occurred during the study (2008-2009): two during relatively warmer months (an August 2008 cyanobacteria bloom and a November 2008 dinoflagellate bloom) followed by increases in both Vibrio species and V. parahaemolyticus, respectively, and three during cooler months (December 2008 through February 2009) caused by dinoflagellates and euglenophytes that were not associated with marked changes in Vibrio abundances. Vibrio concentrations were positively and significantly associated with temperature and dissolved organic matter, dinoflagellate blooms, negatively and significantly associated with suspended solids, but not significantly correlated with chlorophyll or nitrogen. While more research involving longer time series is needed to increase robustness, findings herein suggest that certain HAB species may augment Vibrio occurrences during warmer months.

Junctional relationships between germinal cells and sustentacular cells in the testes of a palaemonid shrimp.

Testes of the palaemonid shrimp Macrobrachium rosenbergii were prepared for study in the light, scanning and transmission electron microscopes and shown to be composed of solid, convoluted cords of tissue composed of two major sets of cells, spermatogenic and sustentacular cells. Among the spermatogenic cells, preleptotene spermatocytes and encysted spermatozoa were of most frequent occurrence. The sustentacular cells sent long, cytoplasmic extensions ramifying between and around tightly packed spermatocytes of the seminiferous cords and separated the spermatocytes from the basal lamina which surrounded the cords. Spermatocytes formed desmosome-like and short gap junctions with one another, while sustentacular cells formed intermediate-like junctions and gap junctions with spermatocytes. No special junctions between one sustentacular cell and another were encountered in the present study.