RESUMO
Phospholipases find versatile applications across industries, including detergent production, food modification, pharmaceuticals (especially in drug delivery systems), and cell signaling research. In this study, we present a strain of Bacillus paranthracis for the first time, demonstrating significant potential in the production of phosphatidylcholine-specific phospholipase C (PC-PLC). The investigation thoroughly examines the B. paranthracis PUMB_17 strain, focusing on the activity of PC-PLC and its purification process. Notably, the PUMB_17 strain displays extracellular PC-PLC production with high specific activity during the late exponential growth phase. To unravel the genetic makeup of PUMB_17, we employed nanopore-based whole-genome sequencing and subsequently conducted a detailed genome annotation. The genome comprises a solitary circular chromosome spanning 5,250,970 bp, featuring a guanine-cytosine ratio of 35.49. Additionally, two plasmids of sizes 64,250 bp and 5845 bp were identified. The annotation analysis reveals the presence of 5328 genes, encompassing 5186 protein-coding sequences, and 142 RNA genes, including 39 rRNAs, 103 tRNAs, and 5 ncRNAs. The aim of this study was to make a comprehensive genomic exploration that promises to enhance our understanding of the previously understudied and recently documented capabilities of Bacillus paranthracis and to shed light on a potential use of the strain in the industrial production of PC-PLC.
RESUMO
The aim of the present study was to carry out a preliminary assessment for the occurrence of bacterial strains resistant to frequently used antibiotics in the sediments beneath the sturgeon cage farm in Kardzhali Dam (Bulgaria). Samples were taken from the top 2 cm of sediments under a fish farm and from a control station in the aquatory of the reservoir in the period July-October 2011. Surveillance of bacterial susceptibility to 16 antimicrobial agents was performed for 160 Gram-negative strains (Pseudomonas mandelii - 100 strains; Hafnia alvei - 30 strains; and Raoultella ornithinolytica - 30 strains). No significant differences in the resistance to the tested antibiotics were observed between the strains isolated from the two stations (analysis of variance, P > 0.05). Widespread resistance to penicillins and certain cephalosporin antibiotics was observed in both stations. None of the studied strains showed resistance to the aminoglycoside antibiotics gentamicin and amikacin, or to ciprofloxacin. Minimal Inhibitory Concentrations (MIC) were determined for five of the tested antimicrobial agents by the microdilution antibiotic sensitivity assay. The data indicate that amikacin, tetracycline and ciprofloxacin effectively suppress the growth of the tested micro-organisms. The isolates from genus Pseudomonas showed the highest MIC and were characterized by the highest percentage of antibiotic resistance.