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191.
MOTIVATION: Prokaryotic organisms have been identified utilizing the sequence variation of the 16S rRNA gene. Variations steer the design of DNA probes for the detection of taxonomic groups or specific organisms. The long-term goal of our project is to create probe arrays capable of identifying 16S rDNA sequences in unknown samples. This necessitated the authentication, categorization and alignment of the >75 000 publicly available '16S' sequences. Preferably, the entire process should be computationally administrated so the aligned collection could periodically absorb 16S rDNA sequences from the public records. A complete multiple sequence alignment would provide a foundation for computational probe selection and facilitates microbial taxonomy and phylogeny. RESULTS: Here we report the alignment and similarity clustering of 62 662 16S rDNA sequences and an approach for designing effective probes for each cluster. A novel alignment compression algorithm, NAST (Nearest Alignment Space Termination), was designed to produce the uniform multiple sequence alignment referred to as the prokMSA. From the prokMSA, 9020 Operational Taxonomic Units (OTUs) were found based on transitive sequence similarities. An automated approach to probe design was straightforward using the prokMSA clustered into OTUs. As a test case, multiple probes were computationally picked for each of the 27 OTUs that were identified within the Staphylococcus Group. The probes were incorporated into a customized microarray and were able to correctly categorize Staphylococcus aureus and Bacillus anthracis into their correct OTUs. Although a successful probe picking strategy is outlined, the main focus of creating the prokMSA was to provide a comprehensive, categorized, updateable 16S rDNA collection useful as a foundation for any probe selection algorithm.  相似文献   
192.
Three anthocyanins were isolated from the red flowers of chenille plant, Acalypha hispida Burm. (Euphorbiaceae) by a combination of chromatographic techniques. Their structures were elucidated mainly by homo- and heteronuclear nuclear magnetic resonance spectroscopy and electrospray mass spectrometry, and supported with complete assignments of 13C NMR resonances. The novel pigment, cyanidin 3-O-(2"-galloyl-6"-O-alpha-rhamnopyranosyl-beta-galactopyranoside) (5%), contains the disaccharide robinoside. The other anthocyanins were identified as cyanidin 3-O-(2"-galloyl-beta-galactopyranoside) (85%), and cyanidin 3-O-beta-galactopyranoside (5%). Anthocyanins acylated with gallic acid have previously been identified in species from the families Nymphaeaceae and Aceraceae, and tentatively in Abrus precatorius (Leguminosae).  相似文献   
193.
We studied the influence of two different extenders, a milk-based versus a TRIS-based extender, using a split-sample technique, on fertility after single and double vaginal inseminations in natural estrous in Norwegian Crossbred ewes. Semen from 21 Norwegian Crossbred rams, all aged approximately 0.5 years, was used for AI of totally 561 Norwegian Crossbred ewes housed at 37 different farms. The farmers performed the inseminations themselves. The ewes were allocated to four parallel groups based on the two extenders and single or double inseminations (2 x 2). The farmers were recommended to inseminate the ewes between 12 and 24 h after detection of natural standing estrous. Vaginal insemination with cooled liquid semen diluted in the milk-based extender resulted in a statistically significant (P<0.01) better fertility of about 10% units both as 25-day NR (non return rate)-and lambing rates, compared with semen diluted in the TRIS-based extender. Double inseminations gave significantly higher (P=0.03) fertility results for both extenders expressed as 25-day NR results, but was not quite statistically significant when expressed as lambing rates (P=0.06) compared with single insemination. The overall 25-day NR results for the milk-based extender (66.4%) after single inseminations is in accordance with both the national results (67.1%) based on vaginal inseminations of 11,377 ewes, as well as with the results from a previous study in the same region achieving a 25-day NR results of 63.3%. In conclusion, liquid ram semen diluted in a milk-based extender and vaginally inseminated once in natural heat, with a semen dose of 150 x 10(6) spermatozoa, gave acceptable fertility results and is to be recommended as the method of choice in Norway.  相似文献   
194.
Two-dimensional electrophoretic analyses of Escherichia coli cells producing recombinant human growth hormone (Nutropin) in fermentations were conducted. The resulting two-dimensional protein profiles were compared with those of nonproducing (blank) cells. A qualitative comparison was performed to address regulatory issues in the biopharmaceutical industry, and a semiquantitative comparison was performed to reveal information about the physiological state of the cells. The protein spots unique to production fermentation profiles were all related to recombinant human growth hormone (hGH); these included intact hGH, charge variants of hGH, and a proteolytically cleaved form of hGH, as expected. There were no E. coli host cell proteins unique to either the production or blank fermentation profiles. Rather, all detectable differences in E. coli proteins were quantitative in nature. Specifically, the levels of IbpA (inclusion body binding protein A), Ivy (inhibitor of vertebrate lysozyme), and a cleaved form of GroEL (Hsp60 homolog) were higher in hGH production profiles, whereas the levels of GlmU protein and PspA (phage shock protein A) were higher in blank profiles. In general, the high degree of similarity between proteomes for hGH-producing and nonproducing cells suggests that E. coli proteins from a nonproducing (blank) fermentation are appropriate for eliciting antibodies that are then used in immunoassays to measure host cell proteins in samples from production fermentations.  相似文献   
195.
A sensitive and specific LC/MS/MS method has been developed and validated for determination of ragaglitazar (NNC 61-0029 or DRF 2725) in human plasma. After solid-phase extraction (SPEC((R)) PLUS C(8)) of plasma, separation was performed on a Symmetry Shield RP8 column (mobile phase: acetonitrile: 10 mM ammonium acetate, pH 5.6 (40:60 v/v)). Two ranges were validated having LLOQs of either 0.500 or 100 ng/ml and linearity up to either 500 or 50000 ng/ml. The intra-assay precision and accuracy were 1.1% to 15.7% and 85.8% to 118.2% (range 0.500-500 ng/ml) and 2.0% to 8.8% and 92.9% to 104.8% (range 100-50000 ng/ml). The method was applied for determination of ragaglitazar in plasma from phase 1 and 2 clinical studies.  相似文献   
196.
A fragment of the amyloid beta protein, βA(25-35), was investigated for its effect on production of reactive oxygen species (ROS) in human neutrophil granulocytes. The formation and identification of ROS were examined by using a 2',7'-dichlorofluorescin (DCF) fluorescence assay, a luminol chemiluminescence assay, electron paramagnetic resonance (EPR) spectroscopy with DEPMPO as a spin trap, and hydroxylation of 4-hydroxybenzoate (4-HBA). The DCF assay showed that βA(25-35) stimulated formation of ROS in a concentration and time dependent manner. The inverted peptide, βA(35-25), gave no response. Also, luminol-amplified chemiluminescence was stimulated by βA(25-35). Incubation with diethyldithiocarbamate (a superoxide dimustase inhibitor) and salicylhydroxamate (SHA; a myeloperoxidase inhibitor) reduced the chemiluminescence. This indicates that hypochlorous acid (HOCl) is formed after exposure to βA(25-35). The EPR spectra indicated a concentration dependent formation of superoxide ( O 2 • - ) - and hydroxyl ( •OH)- radicals. Hydroxylation of 4-HBA to 3,4,-dihydroxybenzoate confirmed production of •OH. This response was attenuated by SHA, indicating involvement of HOCl in formation of •OH. The DCF fluorescence was inhibited with U0126 (an extracellular signal regulated protein kinase (ERK) inhibitor). Further analysis with western blot confirmed phosphorylation of ERK1/2 after exposure to βA(25-35). The phospholipase A 2 (PLA 2 ) inhibitor 7,7-dimethyl-(5Z,8Z)-eicosadienoic acid, and diphenyleneiodonium, which inhibits the NADPH oxidase, also led to a reduction of the DCF fluorescence. The present findings indicate that βA(25-35) stimulates the NADPH oxidase by activating the ERK pathway and PLA 2 . Production of O 2 • - can lead to HOCl and further formation of •OH, which both have a cytotoxic potential.  相似文献   
197.
Digestion and physical activity are associated with large and sometimes opposite changes in several physiological parameters. Gastric acid secretion during digestion causes increased levels of plasma bicarbonate ([HCO-3](pl)), whereas activity leads to a metabolic acidosis with increased lactate and decrease in plasma bicarbonate. Here we describe the combined effects of feeding and activity in the toad Bufo marinus to investigate whether the increased bicarbonate buffering capacity during digestion (the so-called alkaline tide) protects the acid-base disturbance during activity and enhances the subsequent recovery. In addition, we describe the changes in arterial oxygen levels and plasma ion composition, as well as rates of gas exchange, heart rates, and blood pressures. Toads were equipped with catheters in the femoral artery and divided into four experimental regimes: control, digestion, forced activity, and forced activity during the postprandial period (N=6 in each). Digestion induced a significant metabolic alkalosis with increased [HCO-3](pl) that was completely balanced by a respiratory acidosis; that is, increased arterial Pco(2) (P(a)co(2)), so that arterial pH (pH(a)) did not change. Forced activity led to a substantial reduction in pH(a) by 0.43 units, an increase in plasma lactate concentration by 12.5 mmol L(-1), and a reduction in [HCO-3](pl) of similar magnitude. While digesting animals had higher P(a)co(2) and [HCO-3](pl) at rest, the magnitude and duration of the changes in arterial acid-base parameters were similar to those of fasting animals, although the reduction in pH(a) was somewhat lower (0.32 units). In conclusion, while recovery from the acidosis following exercise did not seem to be affected by digestion, the alkaline tide did slightly dampen the reduction in pH(a) during activity.  相似文献   
198.
The effect of acute stress on plasma beta-corticosterone (B), testosterone (T) and estradiol-17beta (E2) concentrations in juvenile alligators collected from sites with varying sediment contaminants was examined in this study. Dramatic increases in plasma B concentrations were observed in alligators from all of the sites after 2 h of capture although females from the intermediate contaminant site exhibited a significantly lower percentage increase in B than females from the other two sites. Males from the site with the highest contaminant levels exhibited elevated initial B concentrations relative to the other sites. This pattern was not observed after 2 h of restraint. Females from the highest contaminant site exhibited depressed initial T when compared to the other sites although this pattern was not observed after 2 h of restraint. Neither E2 nor T decreased after 2 h in females, whereas T concentrations decreased in all males over the same time period. The variance associated with these endpoints was also examined to determine whether it could serve as a more sensitive marker for perturbations of the endocrine system and stress response. Females from the higher and intermediate contaminant sites exhibited the lowest and highest standard errors (respectively) associated with 2 h plasma B concentrations with no differences among mean concentrations suggesting a perturbation of the stress response in these animals that was not detected by examining the means. We concluded that the environmental contaminants could be acting as stressors, leading to the observed differences.  相似文献   
199.
The estrogenic effect of propylparaben was investigated in a rainbow trout Oncorhynchus mykiss test system. Propylparaben was administered orally to sexually immature rainbow trout every second day for up to 10 days in doses between 7 and 1830 mg kg(-1) 2 d(-1) and in the water at 50 and 225 microg l(-1) for 12 days. Plasma vitellogenin was measured before and during the exposures and the concentrations of propylparaben in liver and muscle were determined at the end of experiments. Increases in average plasma vitellogenin levels were seen at oral exposure to 33 mg propylparabenkg(-1) 2 d(-1); the most sensitive fish responded to 7 mg kg(-1). The ED(50) values for increase in vitellogenin synthesis were 35, 31 and 22 mg kg(-1) 2 d(-1) at day 3, 6 and 11, respectively. Exposure to 225 microg propylparabenl(-1) increased vitellogenin synthesis, but exposure to 50 microg l(-1) did not. Propylparaben showed little tendency to bioaccumulation in rainbow trout; less than 1 per thousand of the total amount of propylparaben administered orally at 1830 mg kg(-1) 2 d(-1) over the 10-d experimental period was retained in muscle and liver 24 h after the end of the experiment. Exposure to 225 microg propylparabenl(-1) for 12 d led to concentrations of 6700 and 870 microg propylparabenkg(-1) liver and muscle, respectively. Half lives for propylparaben were 8.6 h in liver and 1.5 h in muscle.  相似文献   
200.
Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta, PTPepsilon, CD45, LAR, PTP1B and SHP-1), using pNPP as substrate. Most noticeable is the increase in the turnover number for PTPbeta with increasing pH and the weak pH-dependence of the turnover number of CD45. The kinetic data for PTPalpha-D1 and PTPalpha-D1D2 suggest that D2 affects the catalysis of pNPP. PTPepsilon and the closely homologous PTPalpha behave differently. The K(m) data were lower for PTPepsilon than those for PTPalpha, while the inverse was observed for the catalytic efficiencies.  相似文献   
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