5 research outputs found
Evaluering af rapporteringssystemet for utilsigtede hĂŚndelser i Frederiksborg Amts SundhedsvĂŚsen
Roles of Rho GTPases in the Regulatory Volume Decrease Process in NIH3T3 Mouse Fibroblasts
Rho family GTP binding proteins are involved in the regulatory volume decrease process in NIH3T3 mouse fibroblasts
The role of Rho GTPases in the regulatory volume decrease (RVD) process following osmotic cell swelling is controversial and has so far only been investigated for the swelling-activated Clâ efflux. We investigated the involvement of RhoA in the RVD process in NIH3T3 mouse fibroblasts, using wild-type cells and three clones expressing constitutively active RhoA (RhoAV14). RhoAV14 expression resulted in an up to fourfold increase in the rate of RVD, measured by large-angle light scattering. The increase in RVD rate correlated with RhoAV14 expression. RVD in wild-type cells was unaffected by the Rho kinase inhibitor Y-27632 and the phosphatidyl-inositol 3 kinase (PI3K) inhibitor wortmannin. The maximal rates of swelling-activated K+ (86Rb+ as tracer) and taurine ([3H]taurine as tracer) efflux after a 30 % reduction in extracellular osmolarity were increased about twofold in cells with maximal RhoAV14 expression compared to wild-type cells, but were unaffected by Y-27632. The volume set points for activation of release of both osmolytes appeared to be reduced by RhoAV14 expression. The maximal taurine efflux rate constant was potentiated by the tyrosine phosphatase inhibitor Na3VO4, and inhibited by the tyrosine kinase inhibitor genistein. The magnitude of the swelling-activated Clâ current (ICl,swell) was higher in RhoAV14 than in wild-type cells after a 7.5 % reduction in extracellular osmolarity, but, in contrast to 86Rb+ and [3H]taurine efflux, similar in both strains after a 30 % reduction in extracellular osmolarity. ICl,swell was inhibited by Y-27632 and strongly potentiated by the myosin light chain kinase inhibitors ML-7 and AV25. It is suggested that RhoA, although not the volume sensor per se, is an important upstream modulator shared by multiple swelling-activated channels on which RhoA exerts its effects via divergent signalling pathways
Recommended from our members
Prevalence of enteric bacterial parasites with respect to anthropogenic factors among commensal rhesus macaques in Dehradun, India
There has been a recent surge in research on primate infectious disease ecology. Two major areas remain relatively unaddressed to date-the prevalence of enteric bacterial parasites and the role of anthropogenic environmental factors in parasite acquisition in commensally living primate populations. In this preliminary assessment, we address both these gaps by assessing the prevalence, and the role of anthropogenic factors in shaping this prevalence, of three enteric bacterial parasites-E . coli O157:H7, Salmonella sp., Shigella sp.-across populations of rhesus macaques (M. mulatta) that live commensally with humans in Dehradun, northern India. Across 10-week study period, we collected data on (1) human-macaque behavioral interactions, (2) macaque and human demographic and activity scans, and (3) macaque fecal samples from the environment at four different locations in Dehradun. Biochemical tests and morphology-based confirmations clearly established the presence of all three enteric bacterial parasites in rhesus macaques. Overall prevalence ranged from 2 to 5 %, with Shigella sp. being the most prevalent. Regression analyses linking anthropogenic factors to bacterial prevalence showed a positive association between rates of macaques eating human garbage and E. coli O157:H7 (β = 0.23, p = 0.083), but a negative association with Salmonella sp. (β = -0.17, p = 0.026). Rather, the prevalence of Salmonella sp. was positively linked to rates of macaque eating provisioned food (β = 0.0012, p = 0.058). Finally, we found no relationship between anthropogenic factors and the prevalence of Shigella sp. Our findings establish the prevalence of enteric bacterial parasites in commensal populations of primates and suggest that although anthropogenic factors are linked to bacterial prevalence, the nature of the relationships may depend on the socioecological/foraging strategies of macaques and the food sources that facilitate the environmental survival of particular types of enteric bacteria over others