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Impranil DLN is a class of plastics belonging to the polyurethane family with high application in textile industries. The aim of this study was to evaluate the potential of native strain to degrade impranil DLN. In this study, yeast strains were isolated from different areas and purified in minimal medium containing 1% impranil. Isolate NS-10 was selected as the superior strain capable of degrading impranil and identified through PCR and ITS gene. Esterase, urease and protease assays were carried out for the superior strain. Finally, the biodegradation of impranil was investigated. In total, 40 yeast strains were isolated and isolate NS-10 was selected as a superior strain based on impranil removal assay. NS-10 strain was identified as Sarocladium kiliense with 100% homology. Enzymatic assays showed that the S.kiliense could produce esterase, urease and protease. In addition, it could produce significant clear zones on impranil plates. Degradation rate for impranil was 100% for 10 g/l within 14 days. Finally, S.kiliense was taken to medium containing pure polyurethane film and the capacity of degradation was investigated by the scanning electron microscopy. Our results indicated that S.kiliense is capable of degrading impranil. These results could contribute to a better insight into the mechanism of plastic biodegradation.
 
 

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Nowadays plant endophytic bacteria have found diverse and useful applications in biotechnology; therefore, much attention has been paid to the isolation, identification, and evaluation of these microorganisms. Since the sterilizing plant tissue surfaces from epiphytic bacteria is difficulty, the efficacy of three different screening methods for endophytic bacteria including 1- HClO sterilization, 2- Periodic sterilization (modified tyndallization) and 3- Triton X100 and HClO sterilization, was evaluated in this study. The modified Tyndallization is an innovative method used in this study to appropriately remove the internal spores of epiphytic bacteria, considered to be an obstacle to the isolation of endophytes. Most of the endophytic bacteria were isolated from dicotyledons and leaves. Endophytic bacteria were also studied for the production of different hydrolase enzymes, whereas the protease enzyme was produced in a wide range of endophytic bacteria in greater quantities than other enzymes. The EndoA strain was molecularly identified and found to be 100% similar to Bacillus halotolerans.

 

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One of the crises in the future for humanity is the epidemic of infectious diseases due to the antibiotic resistance of bacteria. Histatins family has antimicrobial activity against drug-resistant strains and wound healing properties. In this study, the first molecular dynamics simulation on Histatin 3 in the existence of water molecules and ions and also in the existence of Sodium Dodecyl Sulfate (SDS) micelle as a model of membrane bacteria was done separately via the GROMACS 5 package for 50 ns. Then, to increase antibacterial properties, eight mutations were designed and their structures were prepared. Then MD simulation was performed for each mutation with the same previous conditions and binding free energy via the MM/PBSA method of peptides with SDS micelle was calculated. Finally, 950 ns MD simulation in these conditions showed that the D1A-G9W mutation had the best binding free energy to the SDS micelle. Then this peptide and wild Histatin 3 peptide were synthesized, and antimicrobial properties were evaluated experimentally. The results of microbiological tests (MIC) indicated the value of this peptide, which is effective on gram-positive bacteria.