This study aimed to extract and type the plasmids of S. typhi strains and antibiogram. 2 S. typhi strains were selected. One multi-antibiotic resistant strain carried only R-plasmid and the other sensitive strain carried 2 smaller plasmids. Both of them were cultured and extracted DNA plasmid. Then 20 different enzymes were analysed to choose proper enzymes. There were 7 enzymes met the requirements. For DNA of larger plasmid, Kpn 1 and Sca 1 cut to 11 fractions. All of them had lower molecular weight than standard DNA. For DNA of smaller plasmid, Kpn 1 enzyme cut to 16 fractions, BamH 1 cut to 10 fractions, Mlu cut to 9 fractions, Cla cut to 11 fractions, and Bgl II cut to 7 fractions. All these fractions had lower weight than standard DNA. Molecular weight of larger plasmid is 188 206bp X 660D = 124 215 960D (124MD). That of smaller plasmid is 99 731bp X 660D = 65 822 460D.
Plasmids ; Molecular Weight

No abstract available.
DNA* ; Kidney* ; Plasmids*

We investigated the effect of toxin-antitoxin (TA) systems in bla(CTX-M-15)-bearing plasmids of Klebsiella pneumoniae on persister formation. The persister formation rate was notably high in transconjugants in plasmids bearing TA system than the transconjugants in plasmids bearing no TA systems. Activation of relA and spoT expression was higher in transconjugants with plasmids bearing TA systems. Thus, TA systems in plasmids may contribute to the maintenance of bla(CTX-M-15)-bearing plasmids and host survival via persister formation.
Klebsiella pneumoniae ; Klebsiella ; Plasmids

No abstract available.
Drug Resistance, Microbial* ; Plasmids* ; Pneumonia*

No abstract available.
Plasmids* ; Shigella* ; Virulence Factors* ; Virulence*

Aims: Expression of recombinant proteins across a range of different host organisms has profound contribution to the advancement in biotechnology. In this study, we aimed to construct a highly versatile broad host range (BHR) expression vector, designated as pYL101C. Methodology and results: The Golden Gate cloning approach was used to construct pYL101C. Key features of pYL101C include a strong integron promoter (PINTc), a BHR pBBR1 origin of replication (ori), gentamycin resistance gene (GmR) as a selectable marker and a multiple cloning site (MCS) downstream of the promoter for easy-cloning purpose. To verify the functionality of pYL101C, we cloned the superfolder green fluorescent protein (sfGFP) reporter gene into pYL101C and transferred the resultant recombinant plasmid pYL101C::sfGFP into various Gram-negative bacteria. Transformants obtained stably expressed strong green fluorescence under blue light excitation even without selection after four passages. Conclusion, significance and impact of study The constructed BHR expression vector, pYL101C and recombinant pYL101C::sfGFP are stable and can be used to monitor the presence of Gram-negative bacteria, such as endophytes and pathogens in their hosts and environment.
Host Specificity ; Plasmids ; Cloning, Molecular

Recently, treatment for bacillary dysentery have meet many difficulty due to Shigella which antibiotic resistance. Most of Shigella strains also resistant to many antibiotics at the same time (multi-antibiotics). The aim of the research is finding out genes that are encoded antibiotic resistance, features about structure, activity mechanism as well as transmitable of the genes in community. Material and method: researched strains: 100 S.flexneri strains, standard strain: E.coli K12-J5-3. Tecnology: diffused paper slice. The result chosen Sflexneri strains that resistant multi-antibiotic from 237 primary strains. Among them, 100 strains have major resistant type is resistant to 5 kinds of antibiotic. The strains are chosen to receive to E.coli K12J5-3. The percentage of receipt are 56%. Most of receive type don’t get enough resistance to the 5 antibiotics.
Plasmids ; Genes ; Drug Resistance, Microbial ; Shigella flexneri

The toxin-producing bacterium Vibrio cholerae can cause severe diarrhea and has caused seven global pandemics. Traditional viable cell counts and phage plaques are commonly used to evaluate the efficacy of virulent phage clearance of V. cholerae, but these operations are time-consuming and labor-intensive, and difficult to provide real-time changes. It is desirable to develop a simple and real-time method to monitor V. cholerae during phage lysis. In this study, a luminescence-generating plasmid pBBR-pmdh-luxCDABE was transformed into three O1 serogroup drug-resistant strains of V. cholerae. The results showed that the luminescence value as a monitoring index correlates well with the traditional viable cell count method. Monitoring the number of live cells of V. cholerae by measuring the luminescence allowed real-time analysis of the number of bacteria remaining during phage lysis. This method enables repeated, interference-free, continuous multiple-time-point detection of the same sample without the time delay of re-culture or plaque formation, facilitating real-time monitoring and analysis of the interaction between the phage and the host bacteria.
Bacteriophages/genetics* ; Luminescence ; Plasmids ; Vibrio cholerae

Few tools of gene editing have been developed in Bacillus licheniformis at present. In order to enrich the tools, an FLP/FRT gene editing system that can repeatedly use a single selectable marker was constructed in Bacillus licheniformis, and the system was verified by knocking out an alpha amylase gene (amyL), an protease gene (aprE) and knocking in an exogenous Vitreoscilla hemoglobin gene (vgb). First, knock-out plasmids pNZTT-AFKF of amyL and pNZTT-EFKF of aprE were constructed using thermosensitive plasmid pNZT1 as a carrier. The two knock-out plasmids contained respective homology arms, resistance genes and FRT sites. Then the knock-out plasmids were transformed into Bacillus licheniformis and the target genes were replaced by respective deletion cassette via twice homologous exchange. Finally, an expression plasmid containing FLP recombinase reading frane was introduced and mediated the excision of resistance marker. In order to expand the practicability of the system, knock-in plasmid pNZTK-PFTF-vgb was constructed, with which knock-in of vgb at pflB site was carried out successfully. The results showed that amyL and aprE were successfully knocked out and the marker kanamycin cassette exactly excised. The activities of amylase and protease of deletion mutants were reduced by 95.3% and 80.4% respectively. vgb was successfully knocked in at pflB site and the marker tetracycline cassette excised. The expression of integrated vgb was verified via real-time PCR. It is the first time to construct an FLP/FRT system for gene editing in Bacillus licheniformis, which could provide an effective technical means for genetic modification.
Bacillus licheniformis ; Gene Editing ; Plasmids ; Sequence Deletion

Para-aminobenzoate (PABA) is an important chemical for organic synthesis and extensively used in pharmaceutical and dye industry. In recent years, PABA has received increasing attention as a potential component of high-strength polymer. In Escherichia coli, three genes of pabA, pabB and pabC are responsible for PABA production from chorismate in folate synthetic pathway. However, E. coli does not accumulate or accumulates very few amounts of PABA under normal growth condition. In this study, the tyrosine-producing E. coli TYR002 constructed previously was used as the starting strain for developing PABA-producing strain. First, the activity of bifunctional chorismate mutase/prephenate dehydrogenase TyrA in E. coli TYR002 was weakened to reduce the production of tyrosine. Then, three different constitutive promoters were used to regulate the expression of pabA, pabB and pabC in recombinant plasmid which was transformed into E. coli for improving PABA production. The shake-flask fermentation showed that the different combination of constitutive promoters significantly affected the production of PABA, and the highest shake-flask fermentation titer was 0.67 g/L. After further condition optimization, the engineered E. coli produced 6.4 g/L PABA under 5 L fed-batch fermentation. This study could be a good reference for improving microbial production of PABA.
4-Aminobenzoic Acid ; Escherichia coli ; Plasmids