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The Artibeus jamaicensis complex is an important component of the mammal biological diversity of the New World. Although there are numerous studies on the taxonomy and phylogeny of the complex, group relationships are still debated. Previous studies hypothesised that this species originated in South America and later colonised the Antilles Islands either through a northward migration or an eastward migration via Middle America. However, these studies do not include populations from Middle America west of the Yucatan Peninsula, making it difficult to obtain a clear description of the role of these populations in the evolutionary history of the species. In this study, we describe the phylogeography and demographic history of A. jamaicensis populations from Middle America west of the Yucatan Peninsula using cytochrome-b (612 bp) and D-loop (391 bp) mtDNA markers. Our phylogenetic analyses (maximum likelihood and Bayesian inference) did not recover clades corresponding to the previously recognised Middle American subspecies (A. j. triomylus and A. j. yucatanicus); rather, two haplogroups were observed, which showed extensive genetic diversity and strong genetic structure akin to that expected for a Middle American origin for the island populations. Bayesian skyline plots and mismatch distributions revealed that such haplogroups experienced a recent population expansion, which most likely took place in the late Pleistocene (100,000–216,000 BP). These estimates agree with earlier hypotheses that suggested a recent evolutionary history for A. jamaicensis, with hypotheses that suggested the existence of two different lineages migrating northwest from South America to Middle America, and with the possible colonisation of the Antilles Islands derived from both Yucatan Peninsula and northern South America.
During a screening of lactic acid bacteria producing bacteriocin from Cotija cheese, the strain QC38 was isolated. Based on the 16S rRNA gene nucleotide sequencing (516 pb accession no KJ210322) and phylogenetic analysis, the isolate was identified as Pediococcus acidilactici. Neutralized cell-free supernatant was tested for antimicrobial activity against 17 Gram-negative and Gram-positive pathogens. Growth inhibition was achieved against Listeria monocytogenes (supplier or indication or source), Staphylococcus aureus, Vibrio vulnificus, Vibrio cholerae O1 Ogawa, Vibrio cholerae NO 01and Salmonella enterica subsp. Enterica serovar Typhimurium. Bacteriocin-like substance,after heating at 121°C for 15 min it remained stable and its antimicrobial activity was observed at pH ranging from 1.0 to 10.0 butinactivated by α-chymotrypsin and proteinase K. Strain QC38 was able to grow in 1–9% NaCl concentration. The plate overlay assayshowed an approximate size of bacteriocin-like substance between 3.4 and 6.5 kDa. P.acidilactici QC38 harboured a plasmid that contains a gene for a pediocin (PA-1).
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