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81.
Bifidobacterium pseudolongum subsp. globosum DPC479 is an intestinally-derived strain which contains a plasmid, pASV479, 4.8 kb in size. This plasmid has a G + C content of 59% and contains six open reading frames (ORFs), four of which are cryptic. The other two ORFs have 47% and 54% identity, respectively, to the replication and FtsK-like proteins found in a Bifidobacterium breve NCFB 2258 plasmid, indicating that these plasmids, though isolated from differing Bifidobacterium species, are related. Using this plasmid as a backbone, an expression vector, pBIFRIBO, was constructed which exploits a bifidobacteria rRNA promoter. 相似文献
82.
O'Connor EB O'Sullivan O Stanton C Danielsen M Simpson PJ Callanan MJ Ross RP Hill C 《Plasmid》2007,58(2):115-126
The complete nucleotide sequence of pEOC01, a plasmid (11,661 bp) from Pediococcus acidilactici NCIMB 6990 encoding resistance to clindamycin, erythromycin, and streptomycin was determined. The plasmid, which also replicates in Lactococcus and Lactobacillus species contains 16 putative open reading frames (ORFs), including regions annotated to encode replication, plasmid maintenance and multidrug resistance functions. Based on an analysis the plasmid replicates via a theta replicating mechanism closely related to those of many larger Streptococcus and Enterococcus plasmids. Interestingly, genes homologous to a toxin/antitoxin plasmid maintenance system are present and are highly similar to the omega-epsilon-zeta operon of Streptococcus plasmids. The plasmid contains two putative antibiotic resistance homologs, an ermB gene encoding erythromycin and clindamycin resistance, and a streptomycin resistance gene, aadE. Of particular note is the aadE gene which holds 100% identity to an aadE gene found in Campylobacter jejuni plasmid but which probably originated from a Gram-positive source. This observation is significant in that it provides evidence for recent horizontal transfer of streptomycin resistance from a lactic acid bacterium to a Gram-negative intestinal pathogen and as such infers a role for such plasmids for dissemination of antibiotic resistance genes possibly in the human gut. 相似文献
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Swiatecka-Urban A Talebian L Kanno E Moreau-Marquis S Coutermarsh B Hansen K Karlson KH Barnaby R Cheney RE Langford GM Fukuda M Stanton BA 《The Journal of biological chemistry》2007,282(32):23725-23736
Cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl(-) secretion across fluid-transporting epithelia is regulated, in part, by modulating the number of CFTR Cl(-) channels in the plasma membrane by adjusting CFTR endocytosis and recycling. However, the mechanisms that regulate CFTR recycling in airway epithelial cells remain unknown, at least in part, because the recycling itineraries of CFTR in these cells are incompletely understood. In a previous study, we demonstrated that CFTR undergoes trafficking in Rab11a-specific apical recycling endosomes in human airway epithelial cells. Myosin Vb is a plus-end-directed, actin-based mechanoenzyme that facilitates protein trafficking in Rab11a-specific recycling vesicles in several cell model systems. There are no published studies examining the role of myosin Vb in airway epithelial cells. Thus, the goal of this study was to determine whether myosin Vb facilitates CFTR recycling in polarized human airway epithelial cells. Endogenous CFTR formed a complex with endogenous myosin Vb and Rab11a. Silencing myosin Vb by RNA-mediated interference decreased the expression of wild-type CFTR and DeltaF508-CFTR in the apical membrane and decreased CFTR-mediated Cl(-) secretion across polarized human airway epithelial cells. A recombinant tail domain fragment of myosin Vb attenuated the plasma membrane expression of CFTR by arresting CFTR recycling. The dominant-negative effect was dependent on the ability of the myosin Vb tail fragment to interact with Rab11a. Taken together, these data indicate that myosin Vb is required for CFTR recycling in Rab11a-specific apical recycling endosomes in polarized human airway epithelial cells. 相似文献
85.
The role of DNA damage repair in aging of adult stem cells 总被引:3,自引:0,他引:3
DNA repair maintains genomic stability and the loss of DNA repair capacity results in genetic instability that may lead to a decline of cellular function. Adult stem cells are extremely important in the long-term maintenance of tissues throughout life. They regenerate and renew tissues in response to damage and replace senescent terminally differentiated cells that no longer function. Oxidative stress, toxic byproducts, reduced mitochondrial function and external exposures all damage DNA through base modification or mis-incorporation and result in DNA damage. As in most cells, this damage may limit the survival of the stem cell population affecting tissue regeneration and even longevity. This review examines the hypothesis that an age-related loss of DNA damage repair pathways poses a significant threat to stem cell survival and longevity. Normal stem cells appear to have strict control of gene expression and DNA replication whereas stem cells with loss of DNA repair may have altered patterns of proliferation, quiescence and differentiation. Furthermore, stem cells with loss of DNA repair may be susceptible to malignant transformation either directly or through the emergence of cancer-prone stem cells. Human diseases and animal models of loss of DNA repair provide longitudinal analysis of DNA repair processes in stem cell populations and may provide links to the physiology of aging. 相似文献
86.
Stauffer SR Stanton MG Gregro AR Steinbeiser MA Shaffer JR Nantermet PG Barrow JC Rittle KE Collusi D Espeseth AS Lai MT Pietrak BL Holloway MK McGaughey GB Munshi SK Hochman JH Simon AJ Selnick HG Graham SL Vacca JP 《Bioorganic & medicinal chemistry letters》2007,17(6):1788-1792
A series of low-molecular weight 2,6-diamino-isonicotinamide BACE-1 inhibitors containing an amine transition-state isostere were synthesized and shown to be highly potent in both enzymatic and cell-based assays. These inhibitors contain a trans-S,S-methyl cyclopropane P(3) which bind BACE-1 in a 10s-loop down conformation giving rise to highly potent compounds with favorable molecular weight and moderate to high susceptibility to P-glycoprotein (P-gp) efflux. 相似文献
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88.
Katharine Holloway M McGaughey GB Coburn CA Stachel SJ Jones KG Stanton EL Gregro AR Lai MT Crouthamel MC Pietrak BL Munshi SK 《Bioorganic & medicinal chemistry letters》2007,17(3):823-827
Several simple scoring methods were examined for 2 series of beta-secretase (BACE-1) inhibitors to identify a docking/scoring protocol which could be used to design BACE-1 inhibitors in a drug discovery program. Both the PLP1 score and MMFFs interaction energy (E(inter)) performed as well or better than more computationally intensive methods for a set of substrate-based inhibitors, while the latter performed well for both sets of inhibitors. 相似文献
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90.
Sébastien JD Giroux Celmar Alves-Leiva Yann Lécluse Patrick Martin Olivier Albagli Isabelle Godin 《BMC developmental biology》2007,7(1):79