American eel (Anguilla rostrata) populations have declined within their native range along the eastern coast of North America due to factors such as commercial fishing, habitat alteration, and dams. American eel are catadromous fish species, and high mortality rates (>40%) have been observed for freshwater life-stage adult eel passing downstream through hydropower turbines. Lacerations and sectioning of fish have been observed downstream of turbines and these injuries are commonly associated with direct contact with the turbine runner, whether through blade strike or pinching and grinding. Exposure to fluid shear may also be a source of injury, however, little is known about American eel susceptibility to this physical stressor. Eels are considerably flexible when compared to other fish species and lack other morphological characteristics that would make them susceptible to fluid shear, such as protruding eyes, large scales, and large operculum. European eel, which have previously been tested for susceptibility to fluid shear, were found to be resilient. To determine if American eel are also resilient to fluid shear, forty American eel were exposed to a water jet, simulating severe fluid shear (strain rate > 800 s –1 ) that fish may experience when passing downstream through turbines. No immediate or delayed (48 h) signs of injury were observed after exposure to severe fluid shear. Based on this study, and a previous study conducted on American eel susceptibility to barotrauma, the source of injury and mortality of American eel passing through turbines is likely attributed to blade strike or pinching and grinding.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Amylases in the Human Vagina

ABSTRACT Dominance of Lactobacillus species in vaginal communities is a hallmark of healthy conditions in the female genital tract. Key nutrients for lactobacilli include sugars produced when glycogen is degraded by α-amylase in the vagina. While α-amylase activity has been demonstrated in vaginal fluids, it is unclear whether α-amylases are produced solely by the host, bacteria in the vagina, or both. We screened cervicovaginal mucus from 23 reproductive-age women, characterized the species composition of vaginal communities, measured vaginal pH, and determined levels of amylase activity, glycogen, and lactic acid. Based on differences in these measured variables, one sample from each of four individual donors was selected for metagenomic and proteomic analyses. Of eight putative bacterial amylases identified in the assembled bacterial metagenomes, we detected four in vaginal fluids. These amylases were produced by various bacteria in different vaginal communities. Moreover, no two communities were the same in terms of which bacteria were producing amylases. Although we detected bacterial amylases in vaginal fluids, there was no clear association between the bacterial species that was dominant in a community and the level of amylase activity. This association was likely masked by the presence of human α-amylase, which was also detected in vaginal fluids. Finally, the levels of amylase activity and glycogen were only weakly associated. Our findings show, for the first time, that multiple amylases from both bacterial and human origins can be present simultaneously in the vagina. This work also suggests that the link between glycogen, amylase, and Lactobacillus in the vagina is complex. IMPORTANCE In this study, we show that multiple bacteria in the vaginal community produce amylases that hydrolyze glycogen into simpler sugars (i.e., maltose and maltotriose). These sugars serve as “common goods” that sustain bacterial populations in vaginal communities. Given the temporal changes that are observed in the human vaginal microbiome, we expect the kinds of bacterial amylases produced will also vary over time. These differences influence the pool of resources that are broadly shared and shape the species composition of the vaginal bacterial community.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

The Susceptibility of Juvenile American Shad to Rapid Decompression and Fluid Shear Exposure Associated with Simulated Hydroturbine Passage

Throughout many areas of their native range, American shad (Alosa sapidissima) and other Alosine populations are in decline. Though several conditions have influenced these declines, hydropower facilities have had significant negative effects on American shad populations. Hydropower facilities expose ocean-migrating American shad to physical stressors during passage through hydropower facilities, including strike, rapid decompression, and fluid shear. In this laboratory-based study, juvenile American shad were exposed separately to rapid decompression and fluid shear to determine their susceptibility to these stressors and develop dose–response models. These dose–response relationships can help guide the development and/or operation of hydropower turbines and facilities to reduce the negative effects to American shad. Relative to other species, juvenile American shad have a high susceptibility to both rapid decompression and fluid shear. Reducing or preventing exposure to these stressors at hydropower facilities may be a potential method to assist in the effort to restore American shad populations.

13 HYDRO ENERGY↗