Dye decolorization of magnetically retrievable formulation of laccase with amine-functionalized microparticles.

Laccase is an important enzyme used in many industries because of its multi-substrate catalyst. New immobilization agents are excellent tools for enhancing the abilities of this enzyme. In this study, immobilization of laccase on silica microparticles with NH2 (S-NH2) surface modification to use in dye removal applications was aimed. The yield of immobilization by this method was found to be 93.93 ± 2.86% under optimum conditions. In addition, this newly created immobilized enzyme was adapted to a decolorization application with 87.56 ± 1.60% efficiency. Silica microparticles with NH2 (S-NH2) surface modification were used for laccase immobilization and this immobilized laccase had quite good potential. Besides, Random Amplified Polymorphic DNA (RAPD) analysis in evaluating the toxicity of the decolorization process was utilized. After amplification with two RAPD primers, decreased toxicity of dye in this study was observed. This study showed that RAPD analysis in toxicity testing could be accepted as an alternative and practical method that this approach will contribute to the literature in terms of providing fast and reliable results. The use of amine-modified surface silica microparticles for laccase immobilization and RAPD for toxicity testing is a crucial aspect of our investigation.

Investigation of NDM, VIM, KPC and OXA-48 genes, blue-carba and CIM in carbapenem resistant Enterobacterales isolates.

INTRODUCTION: Carbapenem resistance is an emerging problem in Enterobactarales. We aimed to investigate the presence of carbapenemase genes blaNDM, blaKPC, blaVIM and blaOXA-48 and evaluate the phenotypic blue-carba method and carbapenem inactivation method (CIM) in Enterobacterales isolates. METHODOLOGY: Total of 153 Enterobacterales isolates were tested in the study. Presence of blaNDM, blaKPC, blaVIM and blaOXA-48 genes was investigated by polymerase chain reaction (PCR) method. Carbapenemase production of the isolates was also tested by blue-carba method and CIM. RESULTS: The presence of blaOXA-48 gene was detected in 110 (71.4%) and blaNDM gene was detected in 2 (1.3%) of the Enterobacterales isolates by PCR method. None of the isolates were positive for blaKPC and blaVIM genes. The 121 (78.54%) of the isolates were found to be positive by blue-carba method and CIM. And 105 (68.18%) of the isolates were determined as positive by both PCR, blue-carba and CIM. CONCLUSIONS: In our study, 112 (72.7%) of the Enterobacterales isolates were found to be positive for carbapenemase genes (blaoxa-48 and blaNDM), and 121 (78.57%) of different isolates were found to be positive for blue-carba and CIM. However, 105 (68.18%) of the carbapenem resistance isolates found to be positive for all three methods.

Purification and cDNA cloning of a novel neurotoxic peptide (Acra3) from the scorpion Androctonus crassicauda.

Androctonus crassicauda is one of the Southeastern Anatolian scorpions of Turkey with ethno-medical and toxicological importance. Two toxic peptides (Acra1 and Acra2) were isolated and characterized from the venom of this scorpion. In this communication, the isolation of an additional toxin (Acra3) by chromatographic separations (HPLC and TSK-gel sulfopropyl) and its chemical and functional characterization is reported. Acra3 is a 7620Da molecular weight peptide, with 66 amino acid residues crosslinked by four disulfide bridges. The gene coding for this peptide was cloned and sequenced. Acra3 is anticipated to undergo post-translational modifications at the C-terminal region, having an amidated serine as last residue. Injection of Acra3 induces severe neurotoxic events in mice, such as: excitability and convulsions, leading to the death of the animals within a few minutes after injection. Electrophysiological assays conducted with pure Acra3, using cells that specifically expressed sodium channels (Nav1.1-Nav1.6) showed no clear effect. The exact molecular target of Acra3 remained undiscovered, similar to three other scorpion peptides that clustered very closely in the phylogenetic tree included here. The exact target of these four peptides is not very clear.