ABSTRACT
Aim: to investigate whether APOBEC1 [apolipoprotein B mRNA-editing enzyme catalytic polypeptide] from small animal species like mice and rabbits may contribute to the innate immunity against retroviruses and its distribution in different animal tissues
Methods: expression of APOBEC1 proteins from small animal species in a permissive human cell line like GHOST-hi5 and examining the replication of both the wild type HIV-1 R7/3/162 and its delta vif virus. The results have shown that unlike human APOBEC1 which did not show any antiviral activity, APOBEC1 from mice and rabbits was able to suppress the replication of both the wild type HIV-1 R7/3/I62 and its delta vif virus. The expression level of APOBEC1 in different tissues of mice and rabbits was estimated by QPCR using GAPDH [glyceraldehyde-3-phosphate dehydrogenase] as an internal control. The expression level of mouse APOBEC3 was also determined. The results have shown that APOBEC1 is ubiquitously expressed in all rabbit and mouse tissues, mainly in the spleen, thymus, liver and small intestine. This vast distribution similar to APOBEC3 gene without clear role in these cells may contribute to the resistance of mice and rabbits against exogenous retroviruses
ABSTRACT
Aim: the present study aims to estimate the phenotypic and genotypic characteristics of efflux pump systems in Enterobacteriacae clinical isolates
Methods: a total of 60 isolates of Escherichia coli and Klebsiella pneumoniae were studied for antibacterial susceptibility pattern, Effect of efflux pump inhibitors [reserpine, carbonyl cyanide m-chloropheylhydorazone [CCCP] and omperazole] on the MIC of antibacterial agents and ethidium bromide [EtBr] efflux assay, preparing outer membrane proteins, polymerase chain reaction for the detection of efflux genes. Sequencing of some efflux genes, constructing the phylogenetic tree and determining the copy number of the resistance genes in both chromosomal and plasmid DNA
Results: nearly all the clinical isolates were multiple resistant as they were resistant to most antimicrobial classes used in this study. CCCP was found to have the highest effect on decreasing the MIC of different antibiotics comparable with reserpine and omperazole. It was found that all tested E. coli and K. pneumoniae isolates extrude EtBr resulting in decrease in fluorescence over the time of assay. In E. coli isolate No.25 and K. pneumoniae No. 12, only the control cells extrude EtBv resulting in significant loss in fluorescence. In presence of each of reserpine, CCCP and omperazole, an insignificant loss in fluorescence was observed, reflecting blockage of EtBr by these compounds at different levels. All E. coli isolates produced high amount of outer membrane proteirns with apparent molecular mass of 37 and 39 and 50 KDa. These proteins may be designated as OmpC, OmpF and TOIC respectively. Regarding K. pneumonia, all the isolates produced high amount of outer membrane proteins with apparent molecular mass of 37 and 50 KDa and only six isolates produced an outer membrane protein of apparent molecular mass of 39 KDa these proteins may be designated as ompK35 and TOIC and ompK 36 respectively. AcrA and AcrB and TOIC genes was detected and amplified in most of the tested isolates of E. coli and K. pneumoniae genomic and plasmid DNA. AcrA amplicons were visualized at 500 bp for E. coli and 200 bp for K. pneumoniae, AcrB amplicon was detected at 500 bp and TOIC amplicon was detected at 700 bp for both E. coli and K. pneumonia isolates. Moving to the sequencing results, the phylogeny was used to determine the relatedness between different isolates with the observation that different genes like AcrA or AcrB were very closely related to each other on chromosomal DNA and that was the same observation for their gene sequence on plasmid DNA that differs from the chromosomal sequence. It was observed that the chromosomal copy number of AcrA and AcrB genes of the E. coli and K. pneumoniae isolates was nearly the same and after the acquisition of the plasmid, the copy number of' these genes was significantly increased
ABSTRACT
Aim: the aim of this study is to estimate the phenotypic characters of some virulence factors in Escherichia coli and Klebsiella pneumoniae isolated from urinary tract infections and their relative gene expression level
Methods: Escherichia coli and Klebsiella pneumoniae clinical isolates were collected, identified. Their antimicrobial sensitivity pattern was determined. The presence of different virulence factors were evaluated. Relative expression level of different genes responsible for the appearance of the tested virulence factors was evaluated using QRT-PCR and PCR
Results: in this study, when testing the expression level of some genes like BssS and its genes in E. coli, we found that quinolone sensitive isolates of E, coli had shown higher expression level of the tested genes than that o f quinolone resistant E. coli isolates. These results agreed with the phenotypic characters of the tested virulence factors for the same isolates. On the other hand, in K. pneumoniae tested isolates, the expression level of BssS and fimH genes was evaluated and they showed higher expression level in quinolone resistant isolates than sensitive ones. These results agreed with the phenotypic characters of the tested virulence factors for the same isolates. PCR detection of iss gene on both plasmid and chromosomal DNA in K. pneumonia isolates has demonstrated that isolates that exhibit iss gene on both chromosomal and plasmid DNA were those that had shown higher expression at the genetic and phenotypic levels