Ferreira, J. d. O. | Search bioRxiv

bioRxiv2023

Revealing Heavy Metal Resistances in the Yanomami Microbiome

BACKGROUNDThe Amazon hosts invaluable and unique biodiversity as well as mineral resources. As a consequence, there are large illegal and artisanal gold mining areas in indigenous territories. Mercury has been used in gold mining, and some are released into the environment and atmosphere, primarily affecting indigenous as the Yanomami. In addition, other heavy metals have been associated with gold mining and other metal-dispersing activities in the region. OBJECTIVEInvestigation of the Yanomami gut microbiome focusing on metal resistance. METHODSMetagenomic data from the Yanomami gut microbiome were assembled into contigs, and their putative proteins were matched to a database of metal resistance proteins. FINDINGSMost identified proteins have the potential to confer resistance to multiple metals (two or more), followed by mercury, copper, zinc, chromium, arsenic, and others. Operons with potential resistance to mercury, arsenic, chromium, nickel, zinc, copper, copper/silver, and cobalt/nickel were identified. Mercury resistance operon was the most abundant, even though a diversity of operons in the Yanomami microbiome was observed to have the potential to confer resistance to various metals CONCLUSIONThe Yanomami gut microbiome gene composition shows that these people have been exposed directly or indirectly to mercury and other heavy metals. SponsorshipsThis study was partly financed by the Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ); and PAEF (IOC-023-FIO-18-2-47).

microbiology↗

bioRxiv2020

Influence of Activating and Inhibitory Killer Immunoglobulin-Like Receptors (KIR) genes on the recurrence rate of ocular toxoplasmosis in Brazil

BackgroundRecurrence is a hallmark of ocular toxoplasmosis (OT), and conditions that influence its occurrence remain a challenge. Natural killer cells (NK) are effectors cells whose primary function is the cytotoxic activity against many parasites, including Toxoplasma gondii. Among the NK cell receptors, immunoglobulin-like receptors (KIR) deserve attention due to their high polymorphism. This study aimed to analyze the influence of KIR gene polymorphism in the course of OT infection and its association with recurrences after an active episode. MethodsNinety-six patients from the Ophthalmologic Clinic of the National Institute of Infectology Evandro Chagas (INI/Fiocruz/RJ, Brazil) were followed for up to five years. After DNA extraction, genotyping of the patients was performed by PCR-SSO utilizing Luminex equipment for reading. During follow-up, 57.4% had a recurrence. ResultsWe identified 25 KIR genotypes and found a higher frequency of genotypes 1 (31.7%) with worldwide distribution. We note that the KIR2DL2 inhibitor gene and the gene activator KIR2DS2 were more frequent in patients without recurrence (P = 0.03 and P = 0.02, respectively). Additionally, we observed one activating gene, KIR2DS1, associated with more than four times faster progression to the development of recurrent ocular toxoplasmosis than individuals without this gene (aRR = 4.6, P = 0.04). ConclusionThe KIR2DL2 and KIR2DS2 are associated as possible protection markers and the KIR2DS1 acting as a possible susceptibility marker. Additionally, the lower proportion of activating genes observed in individuals with recurrence corroborating with the hypothesis that these individuals are more susceptible to ocular toxoplasmosis recurrence (OTR).

molecular biology↗