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991.
992.
Sattley WM Madigan MT Swingley WD Cheung PC Clocksin KM Conrad AL Dejesa LC Honchak BM Jung DO Karbach LE Kurdoglu A Lahiri S Mastrian SD Page LE Taylor HL Wang ZT Raymond J Chen M Blankenship RE Touchman JW 《Journal of bacteriology》2008,190(13):4687-4696
Despite the fact that heliobacteria are the only phototrophic representatives of the bacterial phylum Firmicutes, genomic analyses of these organisms have yet to be reported. Here we describe the complete sequence and analysis of the genome of Heliobacterium modesticaldum, a thermophilic species belonging to this unique group of phototrophs. The genome is a single 3.1-Mb circular chromosome containing 3,138 open reading frames. As suspected from physiological studies of heliobacteria that have failed to show photoautotrophic growth, genes encoding enzymes for known autotrophic pathways in other phototrophic organisms, including ribulose bisphosphate carboxylase (Calvin cycle), citrate lyase (reverse citric acid cycle), and malyl coenzyme A lyase (3-hydroxypropionate pathway), are not present in the H. modesticaldum genome. Thus, heliobacteria appear to be the only known anaerobic anoxygenic phototrophs that are not capable of autotrophy. Although for some cellular activities, such as nitrogen fixation, there is a full complement of genes in H. modesticaldum, other processes, including carbon metabolism and endosporulation, are more genetically streamlined than they are in most other low-G+C gram-positive bacteria. Moreover, several genes encoding photosynthetic functions in phototrophic purple bacteria are not present in the heliobacteria. In contrast to the nutritional flexibility of many anoxygenic phototrophs, the complete genome sequence of H. modesticaldum reveals an organism with a notable degree of metabolic specialization and genomic reduction. 相似文献
993.
Bove PF Hristova M Wesley UV Olson N Lounsbury KM van der Vliet A 《The Journal of biological chemistry》2008,283(26):17919-17928
Increased synthesis of NO during airway inflammation, caused by induction of nitric-oxide synthase 2 in several lung cell types, may contribute to epithelial injury and permeability. To investigate the consequence of elevated NO production on epithelial function, we exposed cultured monolayers of human bronchial epithelial cells to the NO donor diethylenetriaamine NONOate. At concentrations generating high nanomolar levels of NO, representative of inflammatory conditions, diethylenetriaamine NONOate markedly reduced wound closure in an in vitro scratch injury model, primarily by inhibiting epithelial cell migration. Analysis of signaling pathways and gene expression profiles indicated a rapid induction of the mitogen-activated protein kinase phosphatase (MPK)-1 and decrease in extracellular signal-regulated kinase (ERK)1/2 activation, as well as marked stabilization of hypoxia-inducible factor (HIF)-1alpha and activation of hypoxia-responsive genes, under these conditions. Inhibition of ERK1/2 signaling using U0126 enhanced HIF-1alpha stabilization, implicating ERK1/2 dephosphorylation as a contributing mechanism in NO-mediated HIF-1alpha activation. Activation of HIF-1alpha by the hypoxia mimic cobalt chloride, or cell transfection with a degradation-resistant HIF-1alpha mutant construct inhibited epithelial wound repair, implicating HIF-1alpha in NO-mediated inhibition of cell migration. Conversely, NO-mediated inhibition of epithelial wound closure was largely prevented after small interfering RNA suppression of HIF-1alpha. Finally, NO-mediated inhibition of cell migration was associated with HIF-1alpha-dependent induction of PAI-1 and activation of p53, both negative regulators of epithelial cell migration. Collectively, our results demonstrate that inflammatory levels of NO inhibit epithelial cell migration, because of suppression of ERK1/2 signaling, and activation of HIF-1alpha and p53, with potential consequences for epithelial repair and remodeling during airway inflammation. 相似文献
994.
Quantitative proteomic analysis of bean plants infected by a virulent and avirulent obligate rust fungus 总被引:1,自引:0,他引:1
Lee J Feng J Campbell KB Scheffler BE Garrett WM Thibivilliers S Stacey G Naiman DQ Tucker ML Pastor-Corrales MA Cooper B 《Molecular & cellular proteomics : MCP》2009,8(1):19-31
Plants appear to have two types of active defenses, a broad-spectrum basal system and a system controlled by R-genes providing stronger resistance to some pathogens that break the basal defense. However, it is unknown if the systems are separate entities. Therefore, we analyzed proteins from leaves of the dry bean crop plant Phaseolus vulgaris using a high-throughput liquid chromatography tandem mass spectrometry method. By statistically comparing the amounts of proteins detected in a single plant variety that is susceptible or resistant to infection, depending on the strains of a rust fungus introduced, we defined basal and R-gene-mediated plant defenses at the proteomic level. The data reveal that some basal defense proteins are potential regulators of a strong defense weakened by the fungus and that the R-gene modulates proteins similar to those in the basal system. The results satisfy a new model whereby R-genes are part of the basal system and repair disabled defenses to reinstate strong resistance. 相似文献
995.
The objective of this study was to determine whether a simple, noninvasive method involving administration of isoproterenol could be used to produce myocardial injury and cardiac dysfunction in the mouse heart with a low incidence of mortality. Adult Swiss–Webster mice were injected with isoproterenol (100 mg/kg SC) once daily for 5 d. Myocardial histology and left ventricular (LV) function were assessed 10 to 14 d after the last isoproterenol injection in 14 surviving isoproterenol-treated mice and 15 saline-treated control mice. Left ventricular systolic and diastolic pressures were evaluated in vitro by means of isovolumically contracting, perfused Langendorff preparations. Isoproterenol induced marked endocardial injury, associated with hypertrophy of surviving myocytes, and an increase in myocardial fibrosis (collagen types I and III according to picrosirius red microscopy). The hearts from isoproterenol-treated mice demonstrated decreased LV compliance, as evidenced by an upward shift in the diastolic pressure–volume relationship, with normal LV systolic function. Isoproterenol administration provides a simple, noninvasive means to induce endocardial injury and diastolic dysfunction without significant impairment of systolic function. This model has a low incidence of mortality and may be useful to assess the effects of gene or stem cell therapy on cardiac dysfunction without the potential confounding effects of invasive procedures.Abbreviation: LV, left ventricularThe availability of genetically altered mice provides an opportunity to assess the structural and functional role of specific proteins that are involved in myocardial injury and potential therapeutic interventions. In general, techniques to induce myocardial injury and pathologic hypertrophy in the mouse have required surgical procedures such as ligation of the coronary artery,10,17,24 banding of the aorta,14,26 or implantation of an osmotic minipump to infuse β-adrenergic agonists,12,19,20,31 with associated risk of morbidity or mortality. Moreover, in vascular occlusion models, delivery of gene or stem cell therapy to damaged myocardium might require additional surgery because of the need for direct injection.13 For these reasons, a relatively noninvasive murine model that induces discrete myocardial injury in the presence of a patent coronary circulation, with a low incidence of mortality, would be of interest.Previous investigations27-29 have demonstrated that a single subcutaneous injection of isoproterenol (85 mg/kg) in rats produced myocardial necrosis and fibrosis, while patent coronary vasculature was maintained. Others1,2,30 have shown that the extent of myocardial injury of the rat heart could be increased with repeated injections. A study of chronic isoproterenol infusion20 did not demonstrate significant fibrosis, necrosis, or hypertrophy in the mouse. However, repeated daily injection of isoproterenol (100 mg/kg SC) induces substantial LV fibrosis.7 A more recent study has demonstrated that histologic findings may be dependent on hemodynamic response to the mode of administration and on strain differences.11 The primary purpose of the present study was to define the functional consequences of the adverse structural changes induced in the mouse heart by multiple isoproterenol injections. 相似文献
996.
To establish a proteomic reference map for soybean leaves, we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Tryptic digests of 260 spots were subjected to peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS. Fifty-three of these protein spots were identified by searching NCBInr and SwissProt databases using the Mascot search engine. Sixty-seven spots that were not identified by MALDI-TOF-MS analysis were analyzed with liquid chromatography tandem mass spectrometry (LC-MS/MS), and 66 of these spots were identified by searching against the NCBInr, SwissProt and expressed sequence tag (EST) databases. We have identified a total of 71 unique proteins. The majority of the identified leaf proteins are involved in energy metabolism. The results indicate that 2D-PAGE, combined with MALDI-TOF-MS and LC-MS/MS, is a sensitive and powerful technique for separation and identification of soybean leaf proteins. A summary of the identified proteins and their putative functions is discussed. 相似文献
997.
Recombinant CMP-sialic acid synthetase, cloned from Streptococcus agalactiae serotype V strain 2603 V/R, is bifunctional having both CMP-sialic acid synthetase and acetylhydrolase (acylesterase) activities.
The enzyme is active over a wide pH range with an optimal CMP-sialic acid synthetase activity at pH 9.0 and an optimal acetylhydrolase
activity at pH 8.0. A metal cofactor (either Mg2+ or Mn2+) is required for the CMP-sialic acid synthetase activity but is not for acetylhydrolase activity. Both catalytic functions,
however, are impaired by high concentrations of Mn2+.
Received 10 August 2005; Revisions requested 30 August 2005; Revisions received 1 November 2005; Accepted 2 November 2005 相似文献
998.
Kazuo Nakasuji Kan Usada Takashi Kawasaki Emi Dote Satsuki Hayashi Go Mitsui Kazuya Adachi Michiko Fujihara Yukari Shimbo Koichi Kono 《Biological trace element research》2006,110(2):119-131
Ammonium citratoperoxotitanate IV (TAS-FINE) is a water-soluble titanium complex used to synthesize a photocatalytic titanium(IV)
oxide film. This study was aimed to investigate the LD50, dose-response, time-course response, and renal toxicity of TAS-FINE using an animal model. Serum titanium (S-Ti) and its
24-h urinary excretion (U-Ti) were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES) after a
single oral TAS-FINE administration to male Wistar rats. The LD50 of TAS-FINE was 7.97 g/kg body weight in 24 h, and its half-life was 3.78±1.28 d for S-Ti and 2.19±0.09 d for U-Ti. Although
TAS-FINE was not easily absorbed in the gastrointestinal tract, it was distributed into the bloodstream in a dose-dependent
manner. Within 24 h, 0.189% of administrated Ti was excreted via urine. It was speculated that TAS-FINE formed conjugates
with serum constituents that resulted in nephrotoxicity resulting from an allergic reaction. The observed indices in this
study were revealed to be good indicators for TAS-FINE exposure. The analytical method and animal model described in this
study will help to further elucidate details about human exposure to TAS-FINE, which in recent times has become an occupational
and environmental toxicant of concern. 相似文献
999.
1000.
Aerial vertebrate foragers, e.g. insectivorous bats, martins and swallows, often show gregarious behavior such as colonial breeding, communal roosting and aggregating behavior during foraging. Studies of gregariousness in aerial foragers have mostly focused on colonial breeding or communal roosting, and only a few intensive studies have dealt with gregariousness during foraging. Here, we report on large and stable aggregations of barn swallows, Hirundo rustica, observed during daytime after the breeding season in Japan. Relatively large aggregations of 20 or more birds were located around poultry, pig and cattle farms and mounds of manure. The aggregations were stable in size both within-days and between-days. Their activities consisted only of repeated cycles of foraging and resting around the farms where their prey, the large black soldier fly Hermetia illuceus (>10 mm) and other medium (5–10 mm) flies, was dense. Distributions of swallows around the farms overlapped with the distributions of prey, and the size of the aggregations significantly correlated with the abundance of prey. 相似文献