Microbes and Infection最新文献

Transmissible gastroenteritis virus (TGEV) is a porcine intestinal pathogenic coronavirus that can cause acute intestinal diseases in pigs, especially in suckling piglets under two weeks of age, with a mortality rate of 100 %. Dendritic cells (DCs) are important antigen-presenting cells (APCs) that are essential for the initiation and modulation of immune responses in animals. In this study, we used monocyte-derived porcine DCs as an in vitro model of APCs to further study the pathogenic mechanism of TGEV. Our results demonstrated that TGEV successfully replicates in monocyte-derived porcine DCs, whereas UV-inactivated TGEV failed to infect these cells. Importantly, TGEV infection of DCs led to significant upregulation of swine leukocyte antigen II DR (SLA-DR), a key molecule in the major histocompatibility complex class II (MHC-II) family. We further demonstrated that the ORF3b nonstructural protein of TGEV significantly enhances SLA-DR expression at the transcriptional level in porcine DCs. This study provides new insights into the pathogenic mechanisms of TGEV.

Copper is an essential metal for cellular processes such as detoxification of reactive oxygen species, oxidative phosphorylation, and iron uptake. However, during infection, the host restricts the bioavailability of this micronutrient to the pathogen as a strategy to combat infection. Recently, we have shown the involvement of miRNAs as an adaptive strategy of P. brasiliensis upon metal deprivation such as iron and zinc. However, their role in copper limitation still needs to be elucidated. Our objective was to characterize the expression profile of miRNAs regulated during copper deprivation in P. brasiliensis and the putative altered processes. Through RNAseq analysis and bioinformatics, we identified 14 differentially expressed miRNAs, two of which putatively regulated oxidative stress response, beta-oxidation, glyoxylate cycle, and cell wall remodeling. Our results suggest that metabolic adaptations carried out by P. brasiliensis in copper deprivation are regulated by miRNAs.

Background: The site-of-disease microbiome and predicted metagenome were evaluated in a cross-sectional study involving people with presumptive tuberculous pericarditis. We also explored the interaction between C-reactive protein (CRP) and the microbiome.

Methods: People with effusions requiring diagnostic pericardiocentesis (n=139) provided pericardial fluid for sequencing and blood for CRP measurement.

Results: Pericardial fluid microbiota differed in β-diversity among people with definite (dTB, n=91), probable (pTB, n=25), and non- (nTB, n=23) tuberculous pericarditis. dTBs were Mycobacterium-, Lacticigenium-, and Kocuria-enriched vs. nTBs. HIV-positive dTBs were Mycobacterium-, Bifidobacterium-, Methylobacterium-, and Leptothrix-enriched vs. HIV-negative dTBs. HIV-positive dTBs on ART were Mycobacterium- and Bifidobacterium-depleted vs. those not on ART. dTBs exhibited enrichment in short-chain fatty acid (SCFA) and mycobacterial metabolism pathways vs. nTBs. Additional non-pericardial involvement (pulmonary infiltrates) was associated with Mycobacterium-enrichment and Streptococcus-depletion. Mycobacterium reads were in 34 % (31/91) of dTBs, 8 % (2/25) of pTBs and 17 % (4/23) nTBs. People with CRP above (vs. below) the median value had different β-diversity (Pseudomonas-depleted). No correlation was found between enriched taxa in dTBs and CRP.

Conclusions: Pericardial fluid microbial composition varies by tuberculosis status, HIV (and ART) status and dTBs are enriched in SCFA-associated taxa. The clinical significance, including mycobacterial reads in nTBs and pTBs, requires evaluation.