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Integrase Gene (integrase + gene)
Selected AbstractsDetection and molecular characterization of foamy viruses in Central African chimpanzees of the Pan troglodytes troglodytes and Pan troglodytes vellerosus subspeciesJOURNAL OF MEDICAL PRIMATOLOGY, Issue 2 2006Sara Calattini Abstract Background, Foamy viruses are exogenous retroviruses that are highly endemic in non-human primates (NHPs). Recent studies, mainly performed in North America, indicated frequent simian foamy virus (SFV) infection in persons occupationally exposed to NHPs. This zoonotic infection was demonstrated mainly after bites by chimpanzees [Pan troglodytes (P. t.)] of the West African P. t. verus subspecies in primatology centers or zoos in the USA. Methods, We studied 32 chimpanzees from the Central African subspecies P. t. troglodytes and P. t. vellerosus, originating from Cameroon (29 cases) or Gabon (3 cases). We screened first plasma or sera of the animals with a Western blot detecting the SFVs Gag doublet proteins. Then, we performed two nested polymerase chain reactions (PCRs) amplifying a fragment of the integrase and LTR regions and, finally, we made phylogenetical analyses on the sequences obtained from the integrase PCR products. Results, By serological and/or molecular assays, we detected foamy viruses (FVs) infection in 14 chimpanzees. Sequence comparison and phylogenetic analyses of a 425 bp fragment of the integrase gene obtained for 10 of the 14 positive apes, demonstrated a wide diversity of new FVs strains that belong phylogenetically either to the P. t. troglodytes or P. t. vellerosus foamy viral clade. Conclusions, This study shows that chimpanzees living in these areas of Central Africa are infected by several specific foamy viruses. This raises, in such regions, the potential risk of a human retroviral infection of zoonotic origin linked to chimpanzees contacts, as already exemplified for STLV-1 and SIV infections. [source] Antibiotic resistance in Listeria species isolated from catfish fillets and processing environmentLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2010B.-Y. Chen Abstract Aims:, To investigate the susceptibility of 221 Listeria spp. (86 Listeria monocytogenes, 41 Listeria innocua and 94 Listeria seeligeri-Listeria welshimeri-Listeria ivanovii) isolated from catfish fillets and processing environment to 15 antibiotics. Methods and Results:,Listeria isolates were analysed by disc-diffusion assay for their resistance to 15 drugs. All isolates were resistant to cefotaxime and clindamycin but were sensitive to ampicillin, cephalothin, chloramphenicol, erythromycin, gentamycin, kanamycin, rifampin, streptomycin, sulfamethoxazole/trimethoprim and vancomycin. Unlike L. monocytogenes and L. seeligeri-L. welshimeri-L. ivanovii isolates, 22% of L. innocua isolates displayed tetracycline/oxytetracycline resistance. Screening of tet genes by PCR identified tet(M) gene in the chromosome of all tetracycline/oxytetracycline-resistant L. innocua. However, this gene was not associated with the integrase gene of Tn1545. Repetitive extragenic palindromic- and enterobacterial repetitive intergenic consensus-PCR typing methods showed no genotype-specific tetracycline resistance in the tet(M)-positive strains. Conclusions:, Catfish fillets and processing environment were currently free of L. monocytogenes resistant to antibiotics commonly used in human listeriosis treatment. However, the presence of tet(M) gene in L. innocua raises the possibility of future acquisition of resistance by L. monocytogenes. Significance and Impact of the Study:, These data will be helpful in improving background data on antibiotics resistance strains isolated from food and processing environment. [source] Regulated site-specific recombination of the she pathogenicity island of Shigella flexneriMOLECULAR MICROBIOLOGY, Issue 5 2004Harry Sakellaris Summary The she pathogenicity island (PAI) is a chromosomal, laterally acquired, integrative element of Shigella flexneri that carries genes with established or putative roles in virulence. We demonstrate that spontaneous, precise excision of the element from its integration site in the 3, terminus of the pheV tRNA gene is mediated by an integrase gene (int) and a gene designated rox (regulator of excision), both of which are carried on the she PAI. Integrase-mediated excision occurs via recombination between a 22 bp sequence at the 3, terminus of pheV and an imperfect direct repeat at the pheV -distal boundary of the PAI. Excision leads to the formation of a circular episomal form of the PAI, reminiscent of circular excision intermediates of other mobile elements that are substrates for lateral transfer processes such as conjugation, packaging into phage particles and recombinase-mediated integration into the chromosome. The circle junction consists of the pheV -proximal and pheV -distal boundaries of the PAI converging on a sequence identical to 22 bp at the 3, terminus of pheV. The isolated circle was transferred to Escherichia coli where it integrated specifically into phe tRNA genes, as it does in S. flexneri, independently of recA. We also demonstrate that Rox stimulates, but is not essential for, excision of the she PAI in an integrase-dependent manner. However, Rox does not stimulate excision by activating the transcription of the she PAI integrase gene, suggesting that it has an excisionase function similar to that of a related protein from the P4 satellite element of phage P2. [source] Early emergence of raltegravir resistance mutations in patients receiving HAART salvage regimensJOURNAL OF MEDICAL VIROLOGY, Issue 1 2010Fausto Baldanti Abstract The emergence of drug-resistance mutations in HIV-1 integrase of patients receiving HAART salvage regimens including raltegravir was investigated in 11 heavily pretreated patients (median number of treatment failures 12, range 5,22) within an expanded access program in Pavia, Italy. HIV-1 RNA levels in plasma, CD4+ T-cell counts and sequencing of HIV-1 reverse transcriptase (RT), protease (PR), gp41, and integrase genes were performed at baseline and after 1, 2, 3, 6, and 12 months. The treatment baseline median HIV-1 RNA levels in plasma decreased from 7,510 (range 118,407,107) to <50,copies/ml (range <50,7,562), while median CD4+ T-cell counts remained unchanged (from 212,cells/µl, range 10,764 to 262,cells/µl, range 13,760). Mutations at positions involved in raltegravir resistance (E92G, G140S, Q148H, and N155H) were detected in 4 of 11 (36.3%) patients as early as 1 month after initiating salvage HAART. Of note, the E,,,G change at codon 92 was not reported previously. In two patients with raltegravir resistance, the simultaneous appearance of additional mutations (Y143R and E170A) with an unclear impact on susceptibility to raltegravir or on integrase activity was observed. It is concluded that raltegravir resistant HIV-1 strains may emerge as early as 1 month after initiating HAART salvage regimens. A new mutation associated with the emergence of raltegravir resistance is described, and the simultaneous appearance of primary and secondary mutations was observed. The effect of single and multiple mutations on integrase activity, raltegravir susceptibility, and on the capacity of viral replication remains to be elucidated. J. Med. Virol. 82:116,122, 2010. © 2009 Wiley-Liss, Inc. [source] | ||||||||||