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Ozdemir GB Oryaşın E Bıyık HH Ozteber M Bozdoğan B 《Indian journal of microbiology》2011,51(2):182-187
A collection of 57 enterococcal isolates from different origin (including river, treatment plant, spring and garbage water,
soil, animal, and vegetables from Aydın) was screened for the production of bacteriocins. Enterococci were identified at
species levels as Enterococcus faecium (34), E. hirae (6), E. casseliflavus (4), E. durans (4), E. faecalis (4), E. mundtii (3) and E. avium (2). Of the 57 isolates 40 of them inhibited the growth of at least one indicator bacterium. Based on our PCR results 54
strains possesed enterocin genes. The genes of entA and entB were the most frequently detected structural genes among the PCR positive strains (54 and 53 strains, respectively) and the
entB gene was always associated with entA gene. The highest combination of enterocin genes (24 of 54 strains) detected was entA, entB, entP and entL50A/B. The enterocins AS-48 and CylLLS genes were not found. Three enterococcal isolates, 2 E. faecium and 1 E. hirae were not harbour any of tested enterocin genes. No correlation between the presence of enterocin structural genes and the
origin of the strain was detected, also no relationship seemed to exist between the tested enterocin genes and the activity
spectra of isolates. Genes encoding bacteriocins are widely disseminated among enterocci from different origin and more studies
should be done for evaluate industrial potential of bacteriocins. 相似文献
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Most proteins consist of multiple domains. How do linkers efficiently transfer information between sites that are on different domains to activate the protein? Mere flexibility only implies that the conformations would be sampled. For fast timescales between triggering events and cellular response, which often involves large conformational change, flexibility on its own may not constitute a good solution. We posit that successive conformational states along major allosteric propagation pathways are pre-encoded in linker sequences where each state is encoded by the previous one. The barriers between these states that are hierarchically populated are lower, achieving faster timescales even for large conformational changes. We further propose that evolution has optimized the linker sequences and lengths for efficiency, which explains why mutations in linkers may affect protein function and review the literature in this light. 相似文献
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Ekinci D Ceyhun SB Sentürk M Erdem D Küfrevioğlu Oİ Supuran CT 《Bioorganic & medicinal chemistry》2011,19(2):744-748
Carbonic anhydrase (CA; EC 4.2.1.1) was purified from the gill of the teleost fish Dicentrarchus labrax (European seabass). The purification procedure consisted of a single step affinity chromatography on Sepharose 4B-tyrosine-sulfanilamide. The enzyme was purified 84.9-fold with a yield of 58%, and a specific activity of 838.9 U/mg proteins. It has an optimum pH at 8.0; an optimum temperature at 10°C. The kinetic parameters of this enzyme were determined for its esterase activity, with 4-nitrophenyl acetate (NPA) as substrate. The following anions, H?NSO??, I?, SCN?, NO??, NO??, N??, Br?, Cl?, SO?2?, and F? showed inhibitory effects on the enzyme. Sulfamic acid, iodide, and thiocyanate exhibited the strongest inhibitory action, in the micromolar range (K(i)s of 87-187 μM). NO??, NO?? and N?? were moderate inhibitors, whereas other anions showed only weak actions. All tested anions inhibited the enzyme in a competitive manner. Our findings indicate that these anions inhibit the fish enzyme in a similar manner to other α-CAs from mammals investigated earlier, but the susceptibility to various anions differs significantly between the fish and mammalian CAs. 相似文献
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Psephellus yusufeliensis O. Tugay & Uysal sp. nov. (Asteraceae) from Yusufeli (B7 Artvin-Turkey) is described and illustrated. It is closely related to P. aucheriana (DC) Wagenitz & F. H. Hellw. Diagnostic morphological characters are provided and the relationship to other Psephellus species in Turkey is discussed. The geographical distribution of the new species and other related species are mapped. Notes are also presented on the ecology, biogeography and conservation status of the new species. 相似文献
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Türkoğlu S 《Mutation research》2007,626(1-2):4-14
The effects of the food preservatives sodium benzoate (SB), boric acid (BA), citric acid (CA), potassium citrate (PC) and sodium citrate (SC) have been studied on root tips of Allium cepa L. Roots of A. cepa were treated with a series of concentrations, ranging from 20 to 100 ppm for 5, 10 and 20 h. The results indicate that these food preservatives reduced mitotic division in A. cepa compared with the respective control. Mitotic index values were generally decreased with increasing concentrations and longer treatment times. Additionally, variations in the percentage of mitotic stages were observed. The total percentage of aberrations generally increased with increasing concentrations of these chemicals and the longer period of treatment. Different abnormal mitotic figures were observed in all mitotic phases. Among these abnormalities were anaphase bridges, C-mitosis, micronuclei, lagging, stickiness, breaks and unequal distribution. 相似文献
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