RESUMO
Based on the constructed promoter probe vectors that could replicate both in E. coli and in a cold-adapted bacterium, several candidate promoters were isolated and their activities were evaluated by RT-PCR. The transcription initiation sites and core sequence of promoters were determined by primer extension analysis. A low-temperature expression vector was constructed by using the strongest promoter and a thermolabile alpha-amylase gene was successfully overproduced under control of this promoter at low temperature (7 degrees C), while the secreted alpha-amylase amounted up to 35% of the total extracellular proteins. The expression system is expected to be useful for the production of thermolabile exogenous proteins at low temperatures.
Assuntos
Acinetobacter , Genética , Metabolismo , Adaptação Fisiológica , Genética , Proteínas de Bactérias , Genética , Sequência de Bases , Temperatura Baixa , Escherichia coli , Genética , Metabolismo , Vetores Genéticos , Genética , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Genética , Transformação Genética , alfa-Amilases , GenéticaRESUMO
Chloramphenicol-resistant gene was cloned and analyzed by constructing genomic DNA library of Serratia marcescens KMR-3. It showed that cloned chloramphenicol-resistant gene encoded a protein product of 397 amino acids. The protein belonged to PRK10473 protein, and it showed 92% similarity to drug resistance transporter, Bcr/CflA subfamily of Serratia proteamaculans 568. Regulation elements including promoter, terminator, Shine-Dalgarno (SD) sequence and transcription start site also were identified.
Assuntos
Sequência de Aminoácidos , Sequência de Bases , Resistência ao Cloranfenicol , Genética , Clonagem Molecular , Dados de Sequência Molecular , Serratia marcescens , Classificação , GenéticaRESUMO
To assess the variability of adhesin gene hpaA in differene H pyloristrains with PCR restriction fragment length polymorphism (RFLP) A 710 bp gene hpaA , obtained from 9 different H pylori strains, were digested by Hha Ⅰand Hae Ⅲ individually and analyzed by agarose gel electrophoresis Four different polymorphic types were found in hpaA digested with Hae III and five types with Hha I Clinical isolates of H pylori from Chongqing showed difference among them and remarkably distinguished from foreign standard strains Mongolia gerbil adapted H pylori strain,which were obtained from Mongolia gerbil infected with clinical isolate, also showed inconsistence in hpaA RFLP The hpaA gene from different H pylori strains revealed 1 variability, and this might provide an effective method for developing molecular epidemiology of H pylori