Surveying a Pseudomonas aeruginosa-derived oxidoreductase activity

Screening of Actinomycetes from Rhizosphere Soils for L-glutaminase Production

The integrated experimental and in silico approach highlights soil-derived actinomycetes as versatile and sustainable bioresources with significant pharmaceutical and biotechnological potential, emphasizing their role in combating antimicrobial resistance and enabling the rational development of novel therapeutic and industrial products.

Chitinase: purification and characterization from Alternaria brassicicola and its antibacterial activity.

Chitinases, a class of enzymes found widely in organisms such as bacteria, yeasts, fungi, arthropods, actinomycetes, plants and humans, exhibit significant diversity in their molecular structure, catalytic mechanisms and substrate preferences. A newly characterized extracellular chitinase enzyme was purified from Alternaria brassicicola using methods including ammonium sulfate precipitation and gel filtration chromatography. The enzyme's molecular weight, determined via SDS-PAGE, was found to be 44 kDa. It displays optimal activity at a temperature of 35 °C and remains functional across a temperature range of 30-60 °C. The enzyme exhibits maximum activity at pH 6.6 and shows significant activity within a pH range of 4-8. Metal ion studies revealed that Cu2+, Ca2+ and Zn2+ inhibits its activity, while Mn2+ and Mg2+ enhances it. Furthermore, the enzyme demonstrates inhibitory activity against bacteria such as Staphylococcus aureus and Escherichia coli. These findings underscore its potential applications in various biotechnological and medical fields.

Metabologenomic approach to discover aromatic polyketides, angucycline antimicrobial compounds produced by alkaliphilic Streptomyces.

An alkaliphilic strain of Streptomyces S9 was isolated and taxonomically characterised through multilocus sequence analysis (MLSA) using Streptomyces-specific primers, indicating its genetic potential to biosynthesise aromatic polyketides.

Characterization and depolymerase activity analysis of Acinetobacter baumannii bacteriophage vB_AbaP_IME546.

In this study, we selected Acinetobacter baumannii Ab2897, a strain from our laboratory, as the host, while the lytic bacteriophage vB_AbaP_IME546 was isolated from untreated hospital sewage. We examined the phage's biological characteristics and found that its latent period was under 5 min, with complete lysis of the bacteria occurring within 60 min. The plaques formed by the bacteriophage showed a halo, indicating the presence of an antibacterial protein. Consequently, this phage underwent next-generation sequencing. A BLAST analysis of the assembled genome sequence indicated that vB_AbaP_IME546 is a novel bacteriophage. After carrying out RAST annotation, it was proposed that the tail fiber protein of the bacteriophage might possess depolymerase activity. To further explore this, the ORF49 gene encoding the tail fiber protein was cloned and expressed. The resulting protein, Dp49, was successfully generated. When the protein was applied to a double-layer plate assay, a transparent halo formed in the area surrounding the bacterial growth. This finding confirms that the IME546 phage exhibits depolymerase activity during the lysis of Ab2897.

Biochemical Characterization of a Thermostable Broad-pH Antimicrobial Protein from Bacillus subtilis FB123

YtnP Lactonase: Expression, Characterization, and Potential for Biofilm Control in Membrane Systems.

Membrane biofouling remains a major bottleneck in filtration systems due to the limitations of conventional mitigation strategies. Quorum quenching (QQ) enzymes provide an eco-friendly alternative by disrupting bacterial communication required for biofilm development. YtnP lactonase from Bacillus luti T5 was cloned, expressed, and biochemically characterized. Sequence analysis and structural modeling confirmed its placement in the metallo-β-lactamase superfamily through the conserved HXHXDH motif. The enzyme's activity was further evaluated on nanofiltration membranes against a dual-species biofilm of Pseudomonas mandelii and Staphylococcus aureus. Biofilm formation inhibition on membrane surfaces was visualized using confocal laser scanning microscopy (CLSM), while extracellular polymeric substances (EPS) were characterized by Fourier transform infrared spectroscopy (FTIR). YtnP exhibited remarkable cold-active properties, maintaining catalytic efficiency even at 10 °C. When applied at 120 μg/mL, the enzyme inhibited over 90% of biofilm formation, as confirmed by CLSM. This study provides the evidence of the antibiofouling potential of YtnP in membrane systems, emphasizing its suitability for mild, energy-efficient filtration conditions.