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111.
Gill JJ Summer EJ Russell WK Cologna SM Carlile TM Fuller AC Kitsopoulos K Mebane LM Parkinson BN Sullivan D Carmody LA Gonzalez CF LiPuma JJ Young R 《Journal of bacteriology》2011,193(19):5300-5313
Within the Burkholderia cepacia complex, B. cenocepacia is the most common species associated with aggressive infections in the lungs of cystic fibrosis patients, causing disease that is often refractive to treatment by antibiotics. Phage therapy may be a potential alternative form of treatment for these infections. Here we describe the genome of the previously described therapeutic B. cenocepacia podophage BcepIL02 and its close relative, Bcep22. Phage Bcep22 was found to contain a circularly permuted genome of 63,882 bp containing 77 genes; BcepIL02 was found to be 62,714 bp and contains 76 predicted genes. Major virion-associated proteins were identified by proteomic analysis. We propose that these phages comprise the founding members of a novel podophage lineage, the Bcep22-like phages. Among the interesting features of these phages are a series of tandemly repeated putative tail fiber genes that are similar to each other and also to one or more such genes in the other phages. Both phages also contain an extremely large (ca. 4,600-amino-acid), virion-associated, multidomain protein that accounts for over 20% of the phages' coding capacity, is widely distributed among other bacterial and phage genomes, and may be involved in facilitating DNA entry in both phage and other mobile DNA elements. The phages, which were previously presumed to be virulent, show evidence of a temperate lifestyle but are apparently unable to form stable lysogens in their hosts. This ambiguity complicates determination of a phage lifestyle, a key consideration in the selection of therapeutic phages. 相似文献
112.
Cooksey RC Jhung MA Yakrus MA Butler WR Adékambi T Morlock GP Williams M Shams AM Jensen BJ Morey RE Charles N Toney SR Jost KC Dunbar DF Bennett V Kuan M Srinivasan A 《Applied and environmental microbiology》2008,74(8):2480-2487
Between March and May 2006, a Texas hospital identified five Mycobacterium mucogenicum bloodstream infections among hospitalized oncology patients using fluorescence high-performance liquid chromatography analysis of mycolic acids. Isolates from blood cultures were compared to 16 isolates from environmental sites or water associated with this ward. These isolates were further characterized by hsp65, 16S rRNA, and rpoB gene sequencing, hsp65 PCR restriction analysis, and molecular typing methods, including repetitive element PCR, random amplified polymorphic DNA PCR, and pulsed-field gel electrophoresis (PFGE) of large restriction fragments. Three of five patient isolates were confirmed as M. mucogenicum and were in a single cluster as determined by all identification and typing methods. The remaining two patient isolates were identified as different strains of Mycobacterium phocaicum by rpoB sequence analysis. One of these matched an environmental isolate from a swab of a hand shower in the patient's room, while none of the clinical isolates of M. mucogenicum matched environmental strains. Among the other 15 environmental isolates, 11 were identified as M. mucogenicum and 4 as M. phocaicum strains, all of which were unrelated by typing methods. Although the 16S rRNA gene sequences matched for all 14 M. mucogenicum isolates, there were two each of the hsp65 and rpoB sequevars, seven PCR typing patterns, and 12 PFGE patterns. Among the seven M. phocaicum isolates were three 16S rRNA sequevars, two hsp65 sequevars, two rpoB sequevars, six PCR typing patterns, and six PFGE patterns. This outbreak represents the first case of catheter-associated bacteremia caused by M. phocaicum and the first report of clinical isolates from a U.S. hospital. The investigation highlights important differences in the available typing methods for mycobacteria and demonstrates the genetic diversity of these organisms even within narrow confines of time and space. 相似文献
113.
Darias MJ Boglino A Manchado M Ortiz-Delgado JB Estévez A Andree KB Gisbert E 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2012,161(2):130-139
The present study aimed to deepen the understanding of molecular mechanisms governing the absorption and metabolism of some nutrients, growth and development in larvae of Senegalese sole (Solea senegalensis) fed with Artemia enriched with Easy Selco© (ES, INVE) or Aquagrow Gold© (AGG, ABN), which mainly differed in their vitamin A (VA) content and fatty acid composition. The expression profile of genes involved in VA metabolism (crbp2, rbp, crabp1), lipid transport (i-fabp, l-fabp), nuclear receptors for VA and fatty acids (rarα1, rxrα, pparβ), growth (igf1, igf2 and their receptor igf1r) and development (bgp) was analyzed at 22, 30 and 38 days post hatching. The main results suggested that the amount of VA absorbed by larvae is controlled at the intestinal level by crbp2 in both groups, preventing excessive accumulation of this vitamin in the target tissues. The stable expression of i-fabp in the ES group with age could cause an excessive fat accumulation in the intestine inducing, in turn, the steatosis found in the liver and vascular system of these specimens. In liver, the regulation of rbp and fabp expression reflected the status of the physiological functions demanding VA and lipids. The findings revealed that dietary composition induced different strategies for VA and lipid absorption and metabolism affecting, in turn, larval development, growth and health. 相似文献
114.
Jesús Jimnez-Barbero Manuel Bernab Juan Antonio Leal Alicia Prieto Begoa Gmez-Miranda 《Carbohydrate research》1993,250(2):289-299
The structures of cell-wall mannans isolated from Aphamoascus mephitalus, A. Fulvescens, A. verrucosus, and A. reticulisporus have been investigated by chemical analyses and 1D and 2D 1H and 13C NMR techniques. It was found that all of them consists of a relatively simple comb-like structure of the disaccharide repeating block {→ 6)-[-Man p-(1 → 2)]--Man p-(1 →}. The conformations around the -(1 → 2) and -(1 → 6) linkages in thes kinds of polymers were also studied by using molecular mechanics and dynamics calculations, together with NOE data. The results are similar to those found within the oligosaccharide chains of glycoproteins, with a well-defined conformation for the -(1 → 2) linkage and a certain restriction around the -(1 → 6) bonding imposed by the 2-substitution. 相似文献
115.
Microbial mats of twenty-six lakes from Potter Peninsula,King George Island,Antarctica 总被引:3,自引:0,他引:3
The taxonomic composition and ecology of microbial mats were investigated in 26 lentic environments of Potter Peninsula (King George Island, Antarctica) during the summer of 1995/96. These have different limnological characteristics according to the location of the basins. Among the 139 algal taxa registered, 10 are new records for Antarctica. Bacillariophyceae was the dominant class in terms of species richness, followed by the Cyanobacteria and Chlorophyceae. TWINSPAN classification was used to describe six epilithic algal assemblages; Canonical Correspondence Analysis ordination showed that soluble reactive phosphorus, phytoplanktonic chlorophyll a concentration and conductivity were the main sources for the variation in the data. 相似文献
116.
117.
Lin HJ Johansson AS Stenberg G Materi AM Park JM Dai A Zhou H Gim JS Kau IH Hardy SI Parker MW Mannervik B 《Biochimica et biophysica acta》2003,1649(1):16-23
Glutathione transferases (GSTs) are a family of enzymes that detoxify electrophilic compounds, such as carcinogens or drugs, by conjugating them to glutathione. The enzymes have contributed to the understanding of protein structure, due to large differences in amino acid sequence within the family, yet similar architecture and folding. Our objective was to conduct a systematic survey of GSTP1 polymorphisms and their function. Nearly all variants detected were known polymorphisms: IVS4+13C>A; Ile105Val; Ala114Val; and g.2596T>C (Ser185Ser). However, we also found a novel Phe151Leu substitution in an African-American subject (1 out of 111). Kinetic parameters for the conjugation reaction with 1-chloro-2,4-dinitrobenzene (CDNB) were determined for the novel variant enzyme purified via heterologous expression in Escherichia coli. Five substrates were used for measurement of specific activities, including isothiocyanate compounds that occur in cruciferous vegetables (benzylisothiocyanate, phenethylisothiocyanate, and sulforaphane). Such isothiocyanate substrates are potential cancer chemopreventive agents that are conjugated by GSTs. No major change in kinetic parameters was observed. However, the half-life at 50 degrees C of the Leu 151 enzyme was reduced to 12 min, as compared to 28 min for the Phe 151 enzyme. Residue 151 is located at the N-terminus of helix alpha6 in GST motif II, surrounded by hydrophobic residues, and near the conserved "hydrophobic staple" and N-capping box motifs. These local structural elements aid in formation of helix alpha6 and promote proper folding and protein stability. Analysis of the three-dimensional structure showed that substitution of Phe 151 with Leu produces a hydrophobic cavity in the GSTP1 core, thereby destabilizing its structure. Phe151Leu represents one of the first-described allelic variations in a protein folding motif. 相似文献
118.
Coprophilous fungi of the horse 总被引:1,自引:0,他引:1
A total of 1267 microfungi, including 35 Myxomycetes, were recorded from the fecal samples of the 60 horses; of these 395 were found on 20 saddle-horse feces, 363 on 20 race-horses and 509 on 20 working-horses. Eighty two species representing 53 genera were recorded; of these 7 were Zygomycetes, 18 Ascomycetes, 1 Basidiomycetes and 25 Fungi Imperfecti: 2 Myxomycetes. Common coprophilous fungi are in decreasing orderPilobolus kleinii, Saccobolus depauperatus, Mucor hiemalis, Lasiobolus ciliatus, Podospora curvula, Petriella guttulata, M. circinelloides, Coprinus radiatus, Dictyostelium mucoroides, Sordaria fimicola, C. miser, C. stercorarius, Acremonium sp., Coprotus granuliformis, Graphium putredinis, Iodophanus carneus, Chaetomium murorum, Podospora communis, P. inaequalis, P. setosa, Saccobolus versicolor andCladosporium cucumerinum. Species ofMyrothecium verrucaria, Actinomucor elegans, Kernia nitida, Spiculostilbella dendritica andMucorparvispora were found exclusively in working-horses feces.Badhamia sp., Anixiopsis stercoraria, Echinobotryum state ofD. stemonitis, Geotrichum candidum andOidiodendron sp. were found only in saddle-horses feces.Chlamidomyces palmarum andPhilocopra sp. were found exclusively in race-horses feces.Notes on infrequent or interesting fungi includeThamnostylum piriforme, Phialocephala dimorphospora, Rhopalomyces elegans andSpiculostilbella dendritica. 相似文献
119.
Pedro Josué Trejo-Soto Alicia Hernández-Campos Antonio Romo-Mancillas José L. Medina-Franco 《Journal of biomolecular structure & dynamics》2018,36(2):423-442
The AKT isoforms are a group of key kinases that play a critical role in tumorigenesis. These enzymes are overexpressed in different types of cancers, such as breast, colon, prostate, ovarian, and lung. Because of its relevance the AKT isoforms are attractive targets for the design of anticancer molecules. However, it has been found that AKT1 and AKT3 isoforms have a main role in tumor progression and metastasis; thus, the identification of AKT isoforms specific inhibitors seems to be a challenge. Previously, we identified an ATP binding pocket pan-AKT inhibitor, this compound is a 2,4,6-trisubstituted pyridine (compound 11), which represents a new interesting scaffold for the developing of AKT inhibitors. Starting from the 2,4,6-trisubstituted pyridine scaffold, and guided by structure-based design technique, 42 new inhibitors were designed and further evaluated in the three AKT isoforms by multiple docking approach and molecular dynamics. Results showed that seven compounds presented binding selectivity for AKT1 and AKT3, better than for AKT2. The binding affinities of these seven compounds on AKT1 and AKT3 isoforms were mainly determined by hydrophobic contributions between the aromatic portion at position 4 of the pyridine ring with residues Phe236/234, Phe237/235, Phe438/435, and Phe442/439 in the ATP binding pocket. Results presented in this work provide an addition knowledge leading to promising selective AKT inhibitors. 相似文献
120.
H. Lisle Gibbs Libia Sanz Alicia Prez Alexander Ochoa Alyssa T.B. Hassinger Matthew L. Holding Juan J. Calvete 《Molecular ecology》2020,29(15):2871-2888
Understanding how interspecific interactions mould the molecular basis of adaptations in coevolving species is a long‐sought goal of evolutionary biology. Venom in predators and venom resistance proteins in prey are coevolving molecular phenotypes, and while venoms are highly complex mixtures it is unclear if prey respond with equally complex resistance traits. Here, we use a novel molecular methodology based on protein affinity columns to capture and identify candidate blood serum resistance proteins (“venom interactive proteins” [VIPs]) in California Ground Squirrels (Otospermophilus beecheyi) that interact with venom proteins from their main predator, Northern Pacific Rattlesnakes (Crotalus o. oreganus). This assay showed that serum‐based resistance is both population‐ and species‐specific, with serum proteins from ground squirrels showing higher binding affinities for venom proteins of local snakes compared to allopatric individuals. Venom protein specificity assays identified numerous and diverse candidate prey resistance VIPs but also potential targets of venom in prey tissues. Many specific VIPs bind to multiple snake venom proteins and, conversely, single venom proteins bind multiple VIPs, demonstrating that a portion of the squirrel blood serum “resistome” involves broad‐based inhibition of nonself proteins and suggests that resistance involves a toxin scavenging mechanism. Analyses of rates of evolution of VIP protein homologues in related mammals show that most of these proteins evolve under purifying selection possibly due to molecular constraints that limit the evolutionary responses of prey to rapidly evolving snake venom proteins. Our method represents a general approach to identify specific proteins involved in co‐evolutionary interactions between species at the molecular level. 相似文献