bStreptococcus suis is an emerging zoonotic pathogen causing severe infections in pigs and humans. Thirty-three serotypes of S. suis have been identified using serum agglutination. The capsular polysaccharides synthesis (cps) locus is usually conserved among different strains of the same serotype. The cps loci of 15 serotypes have been sequenced, while the loci of the other serotypes remain unknown. In the present study, two to six serotype-specific genes of each of eight serotypes, i.e., serotypes 3, 4, 5, 8, 10, 19, 23, and 25, were identified using cross-hybridization with 93 nucleic acid probes specific to genes in the cps locus, and serotype-specific PCR assays for rapid and sensitive detection of the eight serotypes were then developed. The PCR typing results of the 148 serologically typeable isolates were completely consistent with agglutination results. Furthermore, some autoagglutinating, acapsular, and multiagglutinating strains which could not be differentiated by traditional serum agglutination assays were positive in the PCR assays. Use of the PCR assays with clinical tonsillar specimens showed that the assays are sensitive and able to identify samples with autoagglutinating isolates. To our knowledge, this is the first study to identify the serotype-specific genes of the eight Streptococcus suis serotypes and develop rapid and sensitive PCR assays for the eight serotypes which can be identified only by serum agglutination.
Background The existing diagnostic techniques for detecting schistosomiasis turkestanica, such as aetiological assays, identify infection by parasitic worms via the incubation of miracidia from faeces or observing eggs under microscopy. However, they are limited in the diagnosis of low-grade and prepatent infections, which lead to a high misdetection rates. Therefore, a new method for parasite diagnosis with increased sensitivity is urgently needed. Methods Goats in Nimu County (Tibet, China) infected with Schistosoma turkestanicum in an epidemic area were selected according positivity for the infection by faecal examination. Adult worms were collected, eggs were extracted by the sodium hydroxide (NaOH) erosion method, and soluble worm antigen preparation (SWAP) and soluble egg antigen (SEA) were isolated. The best coating concentration of the antigens and the best degree of dilution for serum were determined by square array experiments, and the optimal blocking solution and serum diluents were selected. The specificity, sensitivity and crossover of the ELISA method were determined using 48 samples of goat sera positive for S. turkestanicum, 100 samples of goat sera negative for S. turkestanicum, and 54 samples of buffalo sera positive for S. japonicum. Serological assays were established with samples from goats naturally grazed in a rural area of Nimu County, Tibet Province, by using the indirect ELISA method for the diagnosis of schistosomiasis, and faeces were collected for miracidia hatching. The sensitivity of the two detection methods was compared. Results Eggs of S. turkestanicum were distributed in the host duodenum and small intestine. Eggs in the host intestinal wall were extracted by the NaOH erosion method, which provided intact
Several studies have found exogenous H2 treatment can alleviate inflammatory damage in inflammatory bowel disease (IBD) animal models, but the mechanisms behind it are less clearly understood. The present study aimed to investigate whether hydrogen-rich saline (HS) attenuates IBD in mice model and the underlying mechanisms. The results showed that HS administration significantly inhibit weight loss and reduce inflammatory damage in dextran sulfate sodium (DSS)-induced acute ulcerative colitis (UC) mice model. We observed that H2 regulates the composition of microbiota by up-regulating the abundance of intestinal specific short chain fatty acids (SCFAs)-producing bacteria. Increased butyrate-producing microbes activated the intracellular butyrate sensor peroxisome proliferator–activated receptor γ (PPAR-γ) signaling pathway, meanwhile decreased the epithelial expression of Nos2, the gene encoding inducible nitric oxide synthase, and thus promoted the recovery of colonic anaerobic environment. Our results also indicated that HS administration reduce intestinal epithelial barrier permeability by decreasing the dextran concentrations in serum, inhibit dysbiotic Enterobacteriaceae expansion, increasing mucus secretion in the colonic lumen, and promoting the expression of intestinal interepithelial tight junction protein. Taken together, we identified the mechanism by which exogenous H2-improved “microbial hydrogen economy” regulates metabolic reprogramming of colonocyte through microbiota-activated PPAR-γ signaling pathway to provide colonic anaerobic environment, and reinforces intestinal epithelial barrier function, thereby promoting the recovery of intestinal homeostasis.
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