Summary. The effect of bacterial lipopolysaccharide (LPS) on the lymphoid organs in C3H/HeN and C3H/HeJ mice was investigated. In C3H/HeN mice, LPS induced apoptosis, characterised by morphological nuclear condensation and DNA fragmentation resulting in thymic atrophy. Similar but less severe changes were also observed in the spleen and lymph nodes. In C3H/HeJ mice, only a slight depletion of lymphocyte numbers was observed in the lymphoid organs. The plasma endotoxin levels were dependent on the LPS dose regardless of mouse strain. On the other hand, the plasma TNF-a levels were significantly elevated in C3H/HeN mice 1 h post-injection and the time course of plasma corticosterone concentration correlated well with the development of apoptosis. These findings suggest that TNF-a and corticosterone may play an important role in LPS-induced apoptosis of lymphocytes.
CIostridium chau woei strain 0 ki nawa produced spontaneous non-mot i I e variants at an unusually high rate (approx. conditions without mutagen. Revertants of non-motile variants were detected at a rate of approximately lo-'. Biochemically, every variant corresponded well with the parental strain. By transmission electron microscopy, three of nine non-motile variants of strain Okinawa were found to be flagellate, while the other six were found to be aflagellate. These phenotypes were confirmed by Western blot analysis using monoclonal antibodies directed against the flagella of C. chauvoei. Moreover, the parental flagellate strain and non-motile flagellate variants were significantly more virulent in mice than non-motile, aflagellate variants. Our results demonstrated that phase variation in motility and flagellation occurs in C. chauwoei, and that the flagella are associated with the full expression of virulence. per generation) under normal
The in vivo effects of bacterial lipopolysaccharide (LPS) on the immune systems of piglets were investigated. Intravenous injection of 0.5 mg of LPS per kilogram of body weight induced apoptosis, which was characterized by nuclear chromatin condensation and fragmentation and a ladder formation of nucleosomal DNA in lymphocytes both in the cortex of the thymus and in the germinal centers and paracortical areas of mesenteric lymph nodes at 24 h postinjection. The levels of endotoxin, tumor necrosis factor alpha, and cortisol in serum increased, generally according to the dose of LPS. These findings suggest that LPS can induce in vivo apoptosis of lymphocytes in piglets and support the notion that cytokine and endocrine responses may play an important role in LPS-induced apoptosis in the immune system.
(Copepoda, Rotifera, Cladocera and Protozoa: Amoeba Testacea) from natural lakes of the middle Rio Doce basin, Minas Gerais, Brazil.Abstract: A list of zooplankton species identified during ten years of studies in the lake system of the middle Rio Doce basin is presented. This lake system integrates the Atlantic Forest biome, a biodiversity hotspot. Three types of studies were achieved by the Brazilian Long Term Ecological Research Program (Brasil-LTER/PELD-UFMG site 4): i) a temporal study (study 1) which sampled four lakes monthly and three lakes twice a year during ten years; ii) a comparative study of limnetic and littoral species composition (study 2) and iii) a spatial study (study 3) that evaluated the species composition of eighteen lakes (eight lakes inside the Rio Doce State Park (RDSP) and ten lakes in its surrounding area) during one year with quarterly sampling. A total of 354 taxa were identified out of which 175 belong to the Rotifera, 95 to the Protozoa (Amoeba Testacea), 55 to Cladocera and 25 to Copepoda. Although many identified species where common in tropical environments, we present new records for the Middle Rio Doce basin. The group of lakes outside the RDSP showed higher exclusive species compared to lakes inside the RDSP. This pattern may be due to higher disturbance intensity and frequency to which the lakes outside RDSP are subjected, being an important factor affecting community structure. These aquatic ecosystems presents more than half of the zooplankton species registered for the Minas Gerais State and is, undoubtedly, one of the Brazil's priorities for conservation, sustaining high diversity in a very small, limited and threatened region. Resumo: Uma lista das espécies de zooplâncton identificadas durante dez anos de estudos no sistema de lagos do médio Rio Doce é apresentada. Este sistema de lagos faz parte do bioma da Mata Atlântica, um hotspot de biodiversidade. Três tipos de estudos foram conduzidos pelo Programa de Pesquisas Ecológicas de Longa Duração (PELD-UFMG site4): i) um estudo temporal, que amostrou quatro lagoas mensalmente e três lagoas semestralmente durante dez anos; ii) um estudo comparativo entre a composição de espécies da região limnética e litorânea e iii) um estudo espacial que avaliou a composição de espécies de dezoito lagoas (oito dentro dos limites do Parque Estadual do Rio Doce (PERD) e dez na sua região do entorno) durante um ano com amostragens trimestrais. Um total de 354 taxa foram identificados sendo 175 pertencentes a Rotifera, 95 a Protozoa (Amoeba Testacea), 55 a Cladocera e 25 a Copepoda. Embora muitas espécies identificadas sejam comuns a ambientes tropicais, são apresentados novos registros para a bacia do Médio Rio Doce. O grupo de lagos fora do PERD apresentou uma maior riqueza exclusiva comparado ao grupo de lagoas dentro do PERD. Este padrão pode ser devido a maiores frequência e intensidade de distúrbios aos quais as lagoas fora do PERD estão sujeitas, já que este é um fator importante que afeta a estruturação de comunidades. Este ecossi...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.