ABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant was first reported in India. Thereafter, the Delta variant became the most prevalent variant globally. Here, we report the complete genome sequence of an early imported case of a SARS-CoV-2 B.1.617.2 AY.122 strain in Iraq. The strain was obtained from a flight passenger from India to Iraq on 20 April 2021.
ABSTRACT
The biological methods for extraction of chitosan were used as alternative procedures for chemical methods In biological methods, the chitosan was extracted from A. flavus by using of Lactobacillus paracasei for demineralization and Bacillus subtilis for deproteinization. The yield of extracted chitosan reached to 53.8%, pH was 7.8 and complete solubility in 1% acitic acid. Purified chitosan had the ability to reduce the biofilm forming capacity of P. aeruginosa clearly visible in light microscopic staining and scanning electron microscopy. The QS dependent phenotype and QS regulated gene expression was significantly reduced in the influence of chitosan. A significant decrease in biofilm formation was seen in the presence of chitosan. The chitosan treatment showed a decrease in the expression of lasR and rhlR genes. Same time production of pyocyanin and proteases was also inhibited in dose dependent manner. Chitosan led to increasing antimicrobial activity of antibiotics and had synergism effect, thus chitosan may be a useful adjuvant agent for the treatment of many bacterial infections in combination with antibiotics.
Subject(s)
Aspergillus flavus/chemistry , Chitosan/pharmacology , Cross Infection/drug therapy , Bacterial Proteins/genetics , Biofilms/drug effects , Chitosan/chemistry , Chitosan/isolation & purification , Cross Infection/genetics , Cross Infection/microbiology , Gene Expression Regulation, Bacterial/drug effects , Humans , Microbial Sensitivity Tests , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/pathogenicity , Quorum Sensing/drug effects , Trans-Activators/geneticsABSTRACT
In this study, a novel isolate of Enterobacter aerogenes isolated from contaminated soils with hydrocarbons had extracellular phytate-degrading activity. Enterobacter aerogenes isolates were identified by biochemical tests and confirmed by16S rRNA gene products (amplified size 211bp) for genotypic detection. The phytase activity was reached to maximum activity when this isolate was cultivated under the optimal conditions which consisted of using minimal salt medium containing 1%(w/v) rice bran as a sole source for carbon and 2% (w/v) yeast extract at pH 5.5 and temperature of 50°C for 48â¯h. The phytase had purified to homogeneity by 50% ammonium sulphate precipitation, ion exchange and gel filtration chromatography with 75.7 fold of purification and a yield of 30.35%. The purified phytase is a single peptide with approximate molecular mass of 42â¯kDa as assessed by SDS-PAGE. The highest degradative ability by Enterobacter aerogenes of black oil, white oil and used engine oil had observed after 72â¯h of incubation. Rapid degradation of black oil and used engine oil had also observed while slow degradation of white oilat all time of incubation. The purified phytase inhibited biofilm formation ability in a dose-dependent manner for all Gram-negative and Gram-positive biofilm-forming bacteria and a significant difference in cell surface hydrophobicity was observed after exposure of planktonic cells to phytase for hour. The hydrolyzing effect of phytase released by Enterobacter aerogenes for complex salts of phosphorus that are insoluble in the soil led to increase of phosphorus concentrations and enhanced the ability of Enterobacter aerogenes to degrade a specific hydrocarbon in contaminated soil so that the phytase has a promising application in bioremediation of contaminated soils with hydrocarbons.
