http://biblioteca.universia.net/verColeccion.do?id=3394 Mostrando recursos 1 - 20 de 996 es http://biblioteca.universia.net/img/logotipo.jpg http://biblioteca.universia.net/ http://biblioteca.universia.net/ficha.do?id=17939924 Smith, G R http://biblioteca.universia.net/ficha.do?id=17939925 Kessin, R H http://biblioteca.universia.net/ficha.do?id=17939926 Kiley, P J; Kaplan, S http://biblioteca.universia.net/ficha.do?id=17939927 Friedberg, E C http://biblioteca.universia.net/ficha.do?id=17939928 Ajitkumar, P; Cherayil, J D http://biblioteca.universia.net/ficha.do?id=17939929 Marciano-Cabral, F http://biblioteca.universia.net/ficha.do?id=17939930 Mayrand, D; Holt, S C http://biblioteca.universia.net/ficha.do?id=17939931 http://biblioteca.universia.net/ficha.do?id=17939932 We present a collection of 182 isogenic strains containing genetically linked antibiotic resistance elements located at approximately 1-min intervals around the Escherichia coli chromosome. At most positions both Tn10 (Tetr) and TN10kan (Kanr) elements are available, so that the collection contains a linked set of alternating antibiotic resistance markers. The map position of each insertion has been aligned to the E. coli genetic map as well as to the Kohara ordered clone bank. These strains ... Singer, M; Baker, T A; Schnitzler, G; Deischel, S M; Goel, M; Dove, W; Jaacks, K J; Grossman, A D; Erickson, J W; Gross, C A http://biblioteca.universia.net/ficha.do?id=17939933 Until 10 years ago, R bodies were known only as diagnostic features by which endosymbionts of paramecia were identified as kappa particles. They were thought to be limited to the cytoplasm of two species in the Paramecium aurelia species complex. Now, R bodies have been found in free-living bacteria and other Paramecium species. The organisms now known to form R bodies include the cytoplasmic kappa endosymbionts of P. biaurelia and P. tetraurelia, the macronuclear kappa endosymbionts of P. ca... Pond, F R; Gibson, I; Lalucat, J; Quackenbush, R L http://biblioteca.universia.net/ficha.do?id=17939934 Ammonia oxidizers (family Nitrobacteraceae) and methanotrophs (family Methylococcaceae) oxidize CO and CH4 to CO2 and NH4+ to NO2-. However, the relative contributions of the two groups of organisms to the metabolism of CO, CH4, and NH4+ in various environments are not known. In the ammonia oxidizers, ammonia monooxygenase, the enzyme responsible for the conversion of NH4+ to NH2OH, also catalyzes the oxidation of CH4 to CH3OH. Ammonia monooxygenase also mediates the transformation of CH3OH t... Bédard, C; Knowles, R http://biblioteca.universia.net/ficha.do?id=17939935 Microbial ureases hydrolyze urea to ammonia and carbon dioxide. Urease activity of an infectious microorganism can contribute to the development of urinary stones, pyelonephritis, gastric ulceration, and other diseases. In contrast to these harmful effects, urease activity of ruminal and gastrointestinal microorganisms can benefit both the microbe and host by recycling (thereby conserving) urea nitrogen. Microbial ureases also play an important role in utilization of environmental nitrogenous... Mobley, H L; Hausinger, R P http://biblioteca.universia.net/ficha.do?id=17939936 The bacterial phosphotransferase system (PTS) functions in a variety of regulatory capacities. One of the best characterized of these is the process by which the PTS regulates inducer uptake and catabolite repression. Early genetic and physiological evidence supported a mechanism whereby the phosphorylation state of an enzyme of the PTS, the enzyme III specific for glucose (IIIGlc), allosterically inhibits the activities of a number of permeases and catabolic enzymes, the lactose, galactose, ... Saier, M H http://biblioteca.universia.net/ficha.do?id=17939937 The capacity of organisms to respond to fluctuations in their osmotic environments is an important physiological process that determines their abilities to thrive in a variety of habitats. The primary response of bacteria to exposure to a high osmotic environment is the accumulation of certain solutes, K+, glutamate, trehalose, proline, and glycinebetaine, at concentrations that are proportional to the osmolarity of the medium. The supposed function of these solutes is to maintain the osmolar... Csonka, L N http://biblioteca.universia.net/ficha.do?id=17939938 Transformation with exogenous deoxyribonucleic acid (DNA) now appears to be possible with all fungal species, or at least all that can be grown in culture. This field of research is at present dominated by Saccharomyces cerevisiae and two filamentous members of the class Ascomycetes, Aspergillus nidulans and Neurospora crassa, with substantial contributions also from fission yeast (Schizosaccharomyces pombe) and another filamentous member of the class Ascomycetes, Podospora anserina. However,... Fincham, J R http://biblioteca.universia.net/ficha.do?id=17939939 The ras proto-oncogene in mammalian cells encodes a 21-kilodalton guanosine triphosphate (GTP)-binding protein. This gene is frequently activated in human cancer. As one approach toward understanding the mechanisms of cellular transformation by ras, the function of this gene in lower eucaryotic organisms has been studied. In the yeast Saccharomyces cerevisiae, the RAS gene products serve as essential function by regulating cyclic adenosine monophosphate metabolism. Stimulation of adenylyl cyc... Gibbs, J B; Marshall, M S http://biblioteca.universia.net/ficha.do?id=17939940 Several fungi can assume either a filamentous or a unicellular morphology in response to changes in environmental conditions. This process, known as dimorphism, is a characteristic of several pathogenic fungi, e.g., Histoplasma capsulatum, Blastomyces dermatitidis, and Paracoccidioides brasiliensis, and appears to be directly related to adaptation from a saprobic to a parasitic existence. H. capsulatum is the most extensively studied of the dimorphic fungi, with a parasitic phase consisting o... Maresca, B; Kobayashi, G S http://biblioteca.universia.net/ficha.do?id=17939941 A bacterial pathogen is a highly adapted microorganism which has the capacity to cause disease. The mechanisms used by pathogenic bacteria to cause infection and disease usually include an interactive group of virulence determinants, sometimes coregulated, which are suited for the interaction of a particular microorganism with a specific host. Because pathogens must overcome similar host barriers, common themes in microbial pathogenesis have evolved. However, these mechanisms are diverse betw... Finlay, B B; Falkow, S http://biblioteca.universia.net/ficha.do?id=17939942 Many plasmids from gram-positive bacteria replicate via a single-stranded deoxyribonucleic acid (ssDNA) intermediate, most probably by a rolling-circle mechanism (these plasmids are referred to in this paper as ssDNA plasmids). Their plus and minus origins are physically separated, and replicative initiations are not simultaneous; it is this feature that allows visualization of ssDNA replication intermediates. The insertion of foreign DNA into an ssDNA plasmid may provoke a high frequency of ... Gruss, A; Ehrlich, S D http://biblioteca.universia.net/ficha.do?id=17939943 A classification for crystal protein genes of Bacillus thuringiensis is presented. Criteria used are the insecticidal spectra and the amino acid sequences of the encoded proteins. Fourteen genes are distinguished, encoding proteins active against either Lepidoptera (cryI), Lepidoptera and Diptera (cryII), Coleoptera (cryIII), or Diptera (cryIV). One gene, cytA, encodes a general cytolytic protein and shows no structural similarities with the other genes. Toxicity studies with single purified ... Höfte, H; Whiteley, H R