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1.
Angus R. Brown Maryanne Covington Robert C. Newton Robert Ramage Patricia Welch 《Journal of peptide science》1996,2(1):40-46
The affinity-based Nα-amino protecting group tetrabenzo [a,c,g,i]fluorenyl-17-methoxycarbonyl (Tbfmoc) has been utilized as a hydrophobic probe to allow the simple, quick and highly effective isolation of a 76 residue cysteine-containing protein (MCP-1). The base-labile Tbfmoc group can be removed under very mild conditions, which preserve the thiol-con taining protein in the reduced state. Oxidative folding was then used to furnish the biologically active β-chemokine MCP-1. 相似文献
2.
Determining endotoxin content of ground beef by the Limulus amoebocyte lysate test as a rapid indicator of microbial quality. 总被引:3,自引:2,他引:1 下载免费PDF全文
Eighty-four samples of ground beef were placed into five half-log cycle groups based upon aerobic plate count (APC) results. Endotoxins were determined by the Limulus amoebocyte lysate test (LAL), and gram-negative viable counts were determined by a violet red bile agar overlay method. Ten samples with a log of APC of less than 5.50 had an APC mean of less than 5.24 and mean endotoxin content by the LAL of 51 ng/g. The 15 samples with APCs between a log of 5.50 and 5.99 had an APC mean of 5.79/g and an endotoxin mean of 103.8 ng/g. Twenty-eight samples had APCs between a log of 6.00 and 6.49 with a mean of 5.28/g and an endotoxin mean of 1106.4 ng/g. The 20 samples with APCs between a log of 6.50 and 7.00 had a mean of 6.77/g and an endotoxin mean of 5067.6 ng/g, while 11 samples had a log of APCs of greater than 7.00 with a mean of 7.53 and an endotoxin mean of 7,472 ng/g. Correlation of half-log cycle mean APC and violet red bile agar counts with mean endotoxin content were both highly significant, indicating that LAL-determined endotoxin content can be used to make a rapid approximation of viable plate counts. Because results can be obtained by LAL in 1 h, the finding of low levels of endotoxins can be taken to indicate low-count meat. The use of additional tests of microbial quality may be necessary when high endotoxin levels are found because the LAL detects both viable and nonviable cells. 相似文献
3.
AB Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(4):261-268
Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight. 相似文献
4.
Background
Organisms are capable of developing different phenotypes by altering the genes they express. This phenotypic plasticity provides a means for species to respond effectively to environmental conditions. One of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. To elucidate how variation in patterns of gene expression affects phenotypic variation, we conducted a study to simultaneously address the influence of developmental stage, sex, and caste on patterns of gene expression in Vespula wasps. Furthermore, we compared the patterns found in this species to those found in other taxa in order to investigate how variation in gene expression leads to phenotypic evolution. 相似文献5.
6.
Varnes JG Gardner DS Santella JB Duncia JV Estrella M Watson PS Clark CM Ko SS Welch P Covington M Stowell N Wadman E Davies P Solomon K Newton RC Trainor GL Decicco CP Wacker DA 《Bioorganic & medicinal chemistry letters》2004,14(7):1645-1649
The discovery of novel and selective small molecule antagonists of the CC Chemokine Receptor-3 (CCR3) is presented. Simple conversion from a 4- to 3-benzylpiperidine gave improved selectivity for CCR3 over the serotonin 5HT(2A) receptor. Chiral resolution and exploration of mono- and disubstitution of the N-propylurea resulted in several 3-benzylpiperidine N-propylureas with CCR3 binding IC(50)s under 5 nM. Data from in vitro calcium mobilization and chemotaxis assays for these compounds ranged from high picomolar to low nanomolar EC(50)s and correlated well with antagonist binding IC(50)s. 相似文献
7.
Structure-activity relationships in the hydrophobic interactions of polyphenols with cellulose and collagen 总被引:1,自引:0,他引:1
Polyphenol interactions with both cellulose and collagen in the solid state have been studied by using chromatography on cellulose and by evaluating the hydrothermal stability of the polyphenol treated sheepskin collagen. Twenty-four polyphenolic compounds were studied, including seven glucose-based gallotannins, five polyalcohol-based gallotannins, and twelve ellagitannins. In the cellulose-polyphenols systems, the polyphenol's affinity to cellulose is positively correlated with their molecular masses, the number of galloyl groups, and their hydrophobicity (logP). The polyphenol treatment increased the hydrothermal stability of collagen samples, and such effects are also positively correlated with the molecular masses, total number of galloyl groups and the hydrophobicity of polyphenols. Ellagitannins showed much weaker interactions with both biopolymers than gallotannins having similar molecular mass, the same number of galloyl groups, and the same number of phenolic hydroxyl groups. It is concluded that, for the polyphenol interactions with both cellulose and collagen, (1) the galloyl group of polyphenols is the functional group; (2) the strength of interactions are positively correlated with molecular size, the number of galloyl groups and the hydrophobicity of polyphenols; (3) the hydrophobic interactions are of great significance; and (4) the interactions are strongly dependent on the flexibility of galloyl groups. 相似文献
8.
9.
The Arabidopsis early flowering 3 (elf3) mutation causes arrhythmic circadian output in continuous light, but there is some evidence of clock function in darkness. Here, we show conclusively that normal circadian function occurs with no alteration of period length in elf3 mutants in dark conditions and that the light-dependent arrhythmia observed in elf3 mutants is pleiotropic on multiple outputs normally expressed at different times of day. Plants overexpressing ELF3 have an increased period length in both constant blue and red light; furthermore, etiolated ELF3-overexpressing seedlings exhibit a decreased acute CAB2 response after a red light pulse, whereas the null mutant is hypersensitive to acute induction. This finding suggests that ELF3 negatively regulates light input to both the clock and its outputs. To determine whether ELF3's action is phase dependent, we examined clock resetting by using light pulses and constructed phase response curves. Absence of ELF3 activity causes a significant alteration of the phase response curve during the subjective night, and constitutive overexpression of ELF3 results in decreased sensitivity to the resetting stimulus, suggesting that ELF3 antagonizes light input to the clock during the night. The phase of ELF3 function correlates with its peak expression levels in the subjective night. ELF3 action, therefore, represents a mechanism by which the oscillator modulates light resetting. 相似文献
10.
Wacker DA Santella JB Gardner DS Varnes JG Estrella M DeLucca GV Ko SS Tanabe K Watson PS Welch PK Covington M Stowell NC Wadman EA Davies P Solomon KA Newton RC Trainor GL Friedman SM Decicco CP Duncia JV 《Bioorganic & medicinal chemistry letters》2002,12(13):1785-1789
CCR3 antagonist leads with IC(50) values in the microM range were converted into low nM binding compounds that displayed in vitro inhibition of human eosinophil chemotaxis induced by human eotaxin. In particular, 4-benzylpiperidin-1-yl-n-propylureas and erythro-3-(4-benzyl-2-(alpha-hydroxyalkyl)piperidin-1-yl)-n-propylureas (obtained via Beak reaction of N-BOC-4-benzylpiperidine) exhibited single digit nanomolar IC(50) values for CCR3. 相似文献