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- 저자 : Kambiz Akbari Noghabi (검색결과 6 건)
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Lee, Ho-Joo,Rho, Jong-Kook,Kambiz Akbari Noghabi,Lee, Seung-Eun,Choi, Mun-Hwan,Yoon, Sung-Chul Plant molecular biology and biotechnology research 2004 Plant molecular biology and biotechnology research Vol.2004 No.-
2-Bromooctanoic acid (2-BrOA) is known to block the formation of polyhydroxyalkanoic acid (PHA) in Pseudomonas fluorescens BM07 without any influence on the cell growth when grown on fructose, but it inhibits the cell growth when grown on octanoate (OA) (Lee et al., Appl. Environ. Microbiol. 67: 4963-4974, 2001). We investigated the role of 2-BrOA in the PHA synthesis of the bacterium grown with mixtures of fructose and fatty acids. OA, 11-phenoxyundecanoic acid (11-POU), and 5-phenylvaleric acid (5-PV) were selected as model substrates. When supplemented with 50mM fructose, all these carboxylic acids suppressed the formation of PHA from fructose, however, the β-oxidation coenzyme A monomers derived from the carboxylic acids were efficiently polymerized, but the conversion yield [(mol of carboxylate substrate converted into PHA)/(mol of carboxylate substrate in the feed)] was low (e.g., maximally ~53% for 5mM 11-POU). Addition of 2-BrOA (up to 5mM) to the mixed carbon sources raised the conversion yield sensitively and effectively only at low levels of the acid substrates (e.g., 2mM 11-POU or 5mM OA): For instance, 100% of 2mM 11-POU were converted into PHA in the presence of 5mM 2-BrOA, whereas only ~10% of the 11-POU were converted in the absence of 2-BrOA. However, at highly saturated suppressing levels (e.g., 5mM 11-POU), 2-BrOA inhibitor showed no significant additional effect on the conversion (60-70% conversion irrespective of 2-BrOA level). The existence of competitive and compensative relationship between 2-BrOA and all the carboxylic acid substrates used may indicate that all the acid substrate-derived inhibiting species bind to the same site as the 2-BrPA inhibiting species does. We, therefore, suggest that 2-BrOA can be used for efficiently increasing the yield of conversion of expensive substituted fatty acids into PHA and then substituted 3-hydroxyacids by hydrolyzing it.
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Improving the Chitinolytic Activity of Bacillus pumilus SG2 by Random Mutagenesis
( Majid Vahed ),( Ebrahim Motalebi ),( Garshasb Rigi ),( Kambiz Akbari Noghabi ),( Mohammad Reza Soudi ),( Mehdi Sadeghi ),( Gholamreza Ahmadian ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.11
Bacillus pumilus SG2, a halotolerant strain, expresses two major chitinases designated ChiS and ChiL that were induced by chitin and secreted into the supernatant. The present work aimed to obtain a mutant with higher chitinolytic activity through mutagenesis of Bacillus pumilus SG2 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on chitin agar and subsequent formation of halos, the mutated strains were examined for degradation of chitin under different conditions. A mutant designated AV2-9 was selected owing to its higher chitinase activity. To search for possible mutations in the whole operon including ChiS and ChiL, the entire chitinase operon, including the intergenic region, promoter, and two areas corresponding to the ChiS and ChiL ORF, was suquenced. Nucleotide sequence analysis of the complete chitinase operon from the SG2 and AV2-9 strains showed the presence of a mutation in the catalytic domain (GH18) of chitinase (ChiL). The results demonstrated that a single base change had occurred in the ChiL sequence in AV2- 9. The wild-type chitinase, ChiL, and the mutant (designated ChiLm) were cloned, expressed, and purified in E. coli. Both enzymes showed similar profiles of activity at different ranges of pH, NaCl concentration, and temperature, but the mutant enzyme showed approximately 30% higher catalytic activity under all the conditions tested. The results obtained in this study showed that the thermal stability of chitinase increased in the mutant strain. Bioinformatics analysis was performed to predict changes in the stability of proteins caused by mutation.
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( Sharafi hakimeh ),( Hadi Maleki ),( Gholamreza Ahmadian ),( Hossein Shahbani Zahiri ),( Neda Sajedinejad ),( Behzad Houshmand ),( Hojatollah Vali ),( Kambiz Akbari Noghabi ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.2
Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at 30oC. Interestingly, antibacterial activity remained unchanged after heating at 121oC for 45 min, 24 h storage in temperature range of 70oC to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.
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Elnaz Khadivinia,Hakimeh Sharafi,Faranak Hadi,Hossein Shahbani Zahiri,Sima Modiri,Azadeh Tohidi,Amir Mousavi,Ali Hatef Salmanian,Kambiz Akbari Noghabi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6
In this study, biosorption of cadmium (II) ions from aqueous solutions by a glyphosate degradingbacterium, Ochrobactrum sp. GDOS, was investigated in batch conditions. The isolate was able to utilize3 mM GP as the sole phosphorous source, favorable to bacterium growth and survival. The effect ofdifferent basic parameters such as initial pH, contact time, initial concentrations of cadmium ion andtemperature on cadmium uptake was evaluated. The adsorption process for Cd (II) is well fitted withLangmuir adsorption isotherm. Experimental data were also tested in terms of biosorption kinetics usingpseudo-first-order and pseudo-second-order kineticmodels. Maximummetal uptake qmax was obtainedas 83.33 mg g1. The sorption process of cadmium onto the Ochrobactrum sp. GDOS biomass followedsecond-order rate kinetic (R2 = 0.9986). A high desorption efficiency was obtained in pH 2. Reusability ofthe biomass was examined under successive biosorption–desorption cycle repeated thrice. Thecharacteristics of the possible interactions between biosorbent and metal ions were also evaluated byscanning electron microscope (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction analysis.
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