Neshat Saffarzadeh, Hamid Moghimi,
Volume 6, Issue 1 (5-2019)
Abstract
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.
Samaneh Khosroshahi, Ensieh Salehghamari, Mohammad Ali Amoozegar, Parvaneh Saffarian,
Volume 6, Issue 4 (12-2019)
Abstract
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.
Zahra Tavakoli, Behnaz Saffar, Karim Mahnam, Rohollah Hemmati,
Volume 11, Issue 3 (12-2024)
Abstract
A significant future challenge for humanity is the rise of infectious disease epidemics stemming from bacterial antibiotic resistance. The Histatin family exhibits antimicrobial properties against drug-resistant strains and promotes wound healing. This study aimed to engineer a novel mutant of Histatin 3 to enhance its antimicrobial efficacy. Initially, molecular dynamics simulations of Histatin 3 were conducted in the presence of water molecules and ions, as well as a Sodium Dodecyl Sulfate (SDS) micelle, which serves as a model for bacterial membranes, using the GROMACS 5 software for a duration of 50 ns. Subsequently, to augment antibacterial properties, eight mutations were designed, and their structures were prepared, followed by individual MD simulations under the same conditions for each mutation. The binding free energy of the peptides with the SDS micelle was calculated using the MM/PBSA method. Ultimately, 950 ns MD simulation revealed that the D1A-G9W mutation exhibited the most favorable binding free energy to the SDS micelle, indicating enhanced interaction of this mutant with microbial membranes. Both this peptide and the wild-type Histatin 3 were synthesized, and their antimicrobial properties were assessed experimentally. The microbiological tests (MIC) on gram-negative and gram-positive stains demonstrated that this peptide was effective against gram-positive bacteria. The findings of this research suggest that, in designing mutations to enhance antimicrobial properties, attention should be given to both the reduction of negative charge and hydrophobicity.
