Draft Genome Sequence of Lactobacillus salivarius KZ-NCB, Isolated from Chicken Cecum

Here, we report the draft genome sequence of Lactobacillus salivarius strain KZ-NCB, which was isolated from the cecum of a healthy chicken from a poultry farm in Kazakhstan.Peer reviewe

Rapid and highly sensitive LAMP-CRISPR/Cas12a-based identification of bovine mastitis milk samples contaminated by Escherichia coli

Mastitis is a prevalent disease affecting dairy cows, leading to significant economic losses in the dairy industry. Conventional diagnostic methods such as microbiology and PCR are expensive and time-consuming, emphasizing the need for alternative diagnostic approaches. The field of novel diagnostics is expanding rapidly due to the application of a modern molecular detection methods based on the CRISPR/Cas system. This system functions by targeting specific genetic sequences of the pathogen, including Escherichia coli, and detects the presence of the pathogen by employing a CRISPR RNA that complements the pathogen's genetic sequence and a Cas12a enzyme that cleaves the particular DNA sequence. In this paper, we present a novel pathogen detection technology that combines the loop-mediated isothermal amplification (LAMP) reaction and Cas12a collateral activity. We have successfully developed a rapid and precise method for identifying E.coli genomic DNA using the LAMP-Cas12a technology, which exhibits high analytical sensitivity within an hour, detecting as low as 1.3 × 101 copies of target DNA. This technology also has the ability to differentiate E. coli from other prevalent mastitis pathogens such as Staphylococcus aureus and Streptococcus agalactiae. Furthermore, we employed a novel MbCas12a nuclease, which demonstrated excellent diagnostic performance in our study when identifying E.coli isolates isolated from bovine mastitis milk samples. The development of such new methods has the potential to expand agricultural tools for use in point-of-care (POC) diagnostics

Comparative Characterization and Identification of Poly-3-hydroxybutyrate Producing Bacteria with Subsequent Optimization of Polymer Yield

In this work, the strains Bacillus megaterium RAZ 3, Azotobacter chrocococcum Az 3, Bacillus araybhattay RA 5 were used as an effective producer of poly-3-hydroxybutyrate P(3HB). The purpose of the study was to isolate and obtain an effective producer of P(3HB) isolated from regional chestnut soils of northern Kazakhstan. This study demonstrates the possibility of combining the protective system of cells to physical stress as a way to optimize the synthesis of PHA by strains. Molecular identification of strains and amplification of the phbC gene, transmission electron microscope (TEM), extracted and dried PHB were subjected to Fourier infrared transmission spectroscopy (FTIR). The melting point of the isolated P(3HB) was determined. The optimal concentration of bean broth for the synthesis of P(3HB) for the modified type of Bacillus megaterium RAZ 3 was 20 g/L, at which the dry weight of cells was 25.7 g/L−1 and P(3HB) yield of 13.83 g/L−1, while the percentage yield of P(3HB) was 53.75%. The FTIR spectra of the extracted polymer showed noticeable peaks at long wavelengths. Based on a proof of concept, this study demonstrates encouraging results

Characterization of biochemical properties of an apurinic/apyrimidinic endonuclease from Helicobacter pylori.

Apurinic/apyrimidinic (AP) endonucleases play critical roles in the repair of abasic sites and strand breaks in DNA. Complete genome sequences of Helicobacter pylori reveal that this bacterial specie has a single AP endonuclease. An H. pylori homolog of Xth (HpXth) is a member of exonuclease III family, which is represented by Escherichia coli Xth. Currently, it remains unknown whether this single AP endonuclease has DNA repair activities similar to those of its counterpart in E. coli and other bacteria. We report that HpXth possesses efficient AP site cleavage, 3'-repair phosphodiesterase, and 3'-phosphatase activities but not the nucleotide incision repair function. Optimal reaction conditions for HpXth's AP endonuclease activity are low ionic strength, high Mg2+ concentration, pH in the range 7-8, and temperature 30 °C. The kinetic parameters measured under steady-state conditions showed that HpXth removes the AP site, 3'-blocking sugar-phosphate, and 3'-terminal phosphate in DNA strand breaks with good efficiency (kcat/KM = 1240, 44, and 5,4 μM-1·min-1, respectively), similar to that of E. coli Xth. As expected, the presence of HpXth protein in AP endonuclease-deficient E. coli xth nfo strain significantly reduced the sensitivity to an alkylating agent and H2O2. Mutation of active site residue D144 in HpXth predicted to be essential for catalysis resulted in a complete loss of enzyme activities. Several important structural features of HpXth were uncovered by homology modeling and phylogenetic analysis. Our data show the DNA substrate specificity of H. pylori AP endonuclease and suggest that HpXth counteracts the genotoxic effects of DNA damage generated by endogenous and host-imposed factors

Characterization of DNA substrate specificities of apurinic/apyrimidinic endonucleases from Mycobacterium tuberculosis

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