Microbiology
Saloomeh Shoaei Naeeni; Gholamhossein Ebrahimipour; Seyed Omid Ranaei Siada; Bijan Bambai
Abstract
L-asparaginase enzyme has various applications, particularly in medicine and food industry. Given some side effects and adverse possession of a minor amount of glutaminase activity, the search for new sources of microbes producing glutaminase-free L-asparaginase type II is underway. The present study ...
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L-asparaginase enzyme has various applications, particularly in medicine and food industry. Given some side effects and adverse possession of a minor amount of glutaminase activity, the search for new sources of microbes producing glutaminase-free L-asparaginase type II is underway. The present study aimed to isolate a bacterium from the Persian Gulf that produces glutaminase-free L-asparaginase type II. It is also aimed to measure the amount of this enzyme and the condition under which it increases. In order to assess the capability of extracellular asparagine production, the isolated bacteria from the seawater were cultured in M9 medium containing phenol red and asparagine. Those bacteria with positive asparaginase test were cultured in M9 medium containing glutamine and phenol red to assess their glutamine activity. The bacterium isolate producing asparaginase was identified using morphological and biochemical means and 16 SrDNA. L-asparaginase enzyme activity of the isolate was explored with a colorimetric method. The effect of anaerobic condition on the amount of L-asparaginase type II activity was explored by culturing under aeration condition and with no aeration. The result showed that the isolated bacterium was Rhizobium nepotum strain SHN1. The asparaginase enzyme activity and the specific activity of this bacterium were 0.467 IU/mL and 0.015 IU/mg, respectively. These characteristics increased to more than 50% in anaerobic condition. The results indicated that microbial flora from the Persian Gulf flora could be a remarkable source of glutaminase-free L-asparaginase enzyme.
Microbiology
Azam Moradi; Mohammad Yaghoobi Avini; GholamHousein Ebrahimipour; AliReza Ghasempour
Abstract
Myxobacteria are soil bacteria that move by gliding and have an astonishing life cycle culminating in fruiting body formation. The myxobacterial strain no.118 was isolated from unexplored soil of Koohrang County, Chaharmahal-o-Bakhtiari Province and tested for potential antimicrobial activity against ...
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Myxobacteria are soil bacteria that move by gliding and have an astonishing life cycle culminating in fruiting body formation. The myxobacterial strain no.118 was isolated from unexplored soil of Koohrang County, Chaharmahal-o-Bakhtiari Province and tested for potential antimicrobial activity against various human pathogens. On the basis of results, strain 118 significantly inhibited growth of E. coli andM. luteus therefore was used for further characterization. Analysis of morphological, biochemical and 16S rRNA gene sequence indicated that this strain belongs to the genus Myxococcus. In addition, neighbor-joining phylogenetic tree confirmed the relationships of this strain to other members of Myxococcus genera. In order to explore the potential bioactivities, extract of the fermented broth culture was prepared with organic solvent extraction method. The methanol extract was subjected to HPLC fractionation against sensitive pathogens. LC/MS analysis resulted in the identification of Myxothiazol and Althiomycinantibiotics in methanol extract of the strain no. 118.
Mohammad Yaghoobi Avini; Gholamhossein Ebrahimipour; Alireza Ghassempour
Abstract
The emergence of drug resistant pathogens indicatesthe need to discovery of new antibiotics. In the search for a new antibioticproducing microorganism, an Alcaligenes faecalis subsp. faecalis strain was isolatedfrom oilpolluted soils near Dezful. One factor at a time was used to find importantvariables ...
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The emergence of drug resistant pathogens indicatesthe need to discovery of new antibiotics. In the search for a new antibioticproducing microorganism, an Alcaligenes faecalis subsp. faecalis strain was isolatedfrom oilpolluted soils near Dezful. One factor at a time was used to find importantvariables in antimicrobial compound production and upon its result pH = 9,temperature 35 ˚C, NH4Cl 0.34%, sodium acetate 2% and K2HPO40.02% have greatest effect on production, respectively. Acetate and NH4Clconcentration, shaker revolution and fermentation time were selected foroptimization by response surface method with central composite design. The bestresult achieved by sodium acetate 1.88%, NH4Cl 0.29%, shaker 3 rpmand fermentation time 6.7 day which had 47% higher production than one factorat a time method. Results also indicated strong interaction between somevariables.
