Disruption of the inositol phosphorylceramide synthase gene affects Trypanosoma cruzi differentiation and infection capacity.

Sphingolipids (SLs) are essential components of all eukaryotic cellular membranes. In fungi, plants and many protozoa, the primary SL is inositol-phosphorylceramide (IPC). Trypanosoma cruzi is a protozoan parasite that causes Chagas disease (CD), a chronic illness for which no vaccines or effective treatments are available. IPC synthase (IPCS) has been considered an ideal target enzyme for drug development because phosphoinositol-containing SL is absent in mammalian cells and the enzyme activity has been described in all parasite forms of T. cruzi. Furthermore, IPCS is an integral membrane protein conserved amongst other kinetoplastids, including Leishmania major, for which specific inhibitors have been identified. Using a CRISPR-Cas9 protocol, we generated T. cruzi knockout (KO) mutants in which both alleles of the IPCS gene were disrupted. We demonstrated that the lack of IPCS activity does not affect epimastigote proliferation or its susceptibility to compounds that have been identified as inhibitors of the L. major IPCS. However, disruption of the T. cruzi IPCS gene negatively affected epimastigote differentiation into metacyclic trypomastigotes as well as proliferation of intracellular amastigotes and differentiation of amastigotes into tissue culture-derived trypomastigotes. In accordance with previous studies suggesting that IPC is a membrane component essential for parasite survival in the mammalian host, we showed that T. cruzi IPCS null mutants are unable to establish an infection in vivo, even in immune deficient mice.

Corrosion-influencing microorganisms in petroliferous regions on a global scale: systematic review, analysis, and scientific synthesis of 16S amplicon metagenomic studies.

The objective of the current systematic review was to evaluate the taxonomic composition and relative abundance of bacteria and archaea associated with the microbiologically influenced corrosion (MIC), and the prediction of their metabolic functions in different sample types from oil production and transport structures worldwide. To accomplish this goal, a total of 552 published studies on the diversity of microbial communities using 16S amplicon metagenomics in oil and gas industry facilities indexed in Scopus, Web of Science, PubMed and OnePetro databases were analyzed on 10th May 2021. The selection of articles was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies that performed amplicon metagenomics to obtain the microbial composition of samples from oil fields were included. Studies that evaluated oil refineries, carried out amplicon metagenomics directly from cultures, and those that used DGGE analysis were removed. Data were thoroughly investigated using multivariate statistics by ordination analysis, bivariate statistics by correlation, and microorganisms' shareability and uniqueness analysis. Additionally, the full deposited databases of 16S rDNA sequences were obtained to perform functional prediction. A total of 69 eligible articles was included for data analysis. The results showed that the sulfidogenic, methanogenic, acid-producing, and nitrate-reducing functional groups were the most expressive, all of which can be directly involved in MIC processes. There were significant positive correlations between microorganisms in the injection water (IW), produced water (PW), and solid deposits (SD) samples, and negative correlations in the PW and SD samples. Only the PW and SD samples displayed genera common to all petroliferous regions, Desulfotomaculum and Thermovirga (PW), and Marinobacter (SD). There was an inferred high microbial activity in the oil fields, with the highest abundances of (i) cofactor, (ii) carrier, and (iii) vitamin biosynthesis, associated with survival metabolism. Additionally, there was the presence of secondary metabolic pathways and defense mechanisms in extreme conditions. Competitive or inhibitory relationships and metabolic patterns were influenced by the physicochemical characteristics of the environments (mainly sulfate concentration) and by human interference (application of biocides and nutrients). Our worldwide baseline study of microbial communities associated with environments of the oil and gas industry will greatly facilitate the establishment of standardized approaches to control MIC.

Hypovitaminosis D and reduced cathelicidin are strongly correlated during the multidrug therapy against leprosy.

Mycobacterium leprae infection depends on the competence of the host immune defense to induce effective protection against this intracellular pathogen. The present study investigated the serum levels of vitamin D and the antimicrobial peptide cathelicidin, to determine the statistical correlation between them in leprosy patients before and post-six months of multidrug therapy (MDT), household contacts, and healthy individuals. Previous studies associated these molecules with high risks to develop mycobacterial diseases, such as tuberculosis and leprosy. A total of 34 leprosy patients [paucibacillary (n = 14), multibacillary (n = 20)], and 25 household contacts were recruited. Eighteen healthy adults were selected as a control group. Serum concentrations of vitamin D (25(OH)VD3) and cathelicidin were measured using high-performance liquid chromatography (HPLC), and an enzyme-linked immunosorbent assay (ELISA) kit, respectively. There were no significant differences in serum levels of 25(OH)VD3 between all groups, and the overall prevalence rate of vitamin D deficiency was 67.1%. Cathelicidin levels were significantly lower in both untreated and treated patients when compared to controls and household contacts (p < 0.05). Strong correlations between hypovitaminosis D and reduced cathelicidin in untreated (r = 0.86) and post-six months of MDT (r = 0.79) leprosy patients were observed. These results suggest that vitamin D status and cathelicidin levels are strongly correlated during multidrug therapy for leprosy and nutritional supplementation from the beginning of treatment could strengthen the immune response against leprosy.