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991.
In laboratory incubation experiments, application of a commercial formulation of the herbicide butachlor (N-butoxymethyl-2-chloro-2',6'-diethyl acetanilide) to three tropical rice soils, widely differing in their physicochemical characteristics, under flooded condition inhibited methane (CH4) production. The inhibitory effect was concentration dependent and most remarkable in the alluvial soil. Thus, following application of butachlor at 5, 10, 50 and 100 microg g(-1) soil, respectively, cumulative CH4 production in the alluvial soil was inhibited by 15%, 31%, 91% and 98% over unamended control. Since CH4 production was less pronounced in the sandy loam and acid sulfate soil, the impact of amendment with butchalor, albeit inhibitory, was less extensive than the alluvial soil. Inhibition of CH4 production in butachlor-amended alluvial soil was related to the prevention in the drop in redox potential as well as low methanogenic bacterial population especially at high concentrations of butachlor. CH4 oxidation was also inhibited in butachlor-amended alluvial soil with the inhibitory effect being more prevalent under flooded condition. Inhibition in CH4 oxidation was related to a reduction in the population of soluble methane monooxygenase producing methanotrophs. Results demonstrate that butachlor, a commonly used herbicide in rice cultivation, even at very low concentrations can affect CH4 production and its oxidation, thereby influencing the biogeochemical cycle of CH4 in flooded rice soils.  相似文献   
992.
The SmI(2)-promoted three-component coupling reaction of thiophene-2-carboxylate, indole-2-carbaldehyde and acetophenone provides an expedient route to a series of tetracyclic carbazolothiophene compounds bearing the indole and thiophene rings. Among these samples, 9-benzyl-4-methyl-4-(4-hydroxyphenyl)-10-oxo-4,10-dihydrocarbazolo[2,3-b]thiophene-2-carboxylic acid (18) shows the most potent inhibition against the endothelin-1 induced increase of intracellular calcium ion concentration.  相似文献   
993.
A series of 21 compounds of trisubstituted pyrimidine derivatives have been synthesized and evaluated for their in vitro topoisomerase II inhibitory activity against filarial parasite Setaria cervi. Out of these, seven compounds (8, 11-14, 25 and 28) have shown 60-80% inhibition at 40 and 20 microg/mL concentration. Five compounds (12, 13, 14, 25 and 28) exhibited 70-80% inhibition at 10 microg/mL concentration and three compounds (13, 14 and 28) have shown 40-60% inhibition at 5 microg/mL concentration. All the above mentioned compounds have shown better topo II inhibitory activity than standard antifilarial drug (DEC) and enzyme topo II inhibitors (Novobiocin, Nalidixic acid).  相似文献   
994.
Synthesis of pyrrolo[2,1-c][1,4]benzodiazepines via azido reductive cyclization process employing FeCl3-NaI reagent system. This methodology has been extended for the preparation of new nicotinamido-pyrrolobenzodiazepine hybrids linked through piperazino-alkane-oxy spacers that exhibit good DNA binding affinity.  相似文献   
995.
The feasibility of laccase production by immobilization of Pleurotus ostreatus 1804 on polyurethane foam (PUF) cubes with respect to media composition was studied in both batch and reactor systems. Enhanced laccase yield was evidenced due to immobilization. A relatively high maximum laccase activity of 312.6 U was observed with immobilized mycelia in shake flasks compared to the maximum laccase activity of free mycelia (272.2 U). It is evident from this study that the culture conditions studied, i.e. biomass level, pH, substrate concentration, yeast extract concentration, Cu2+ concentration, and alcohol nature, showed significant influence on the laccase yield. Gel electrophoretic analysis showed the molecular weight of the laccase produced by immobilized P. ostreatus to be 66 kDa. The laccase yield was significantly higher and more rapid in the packed bed reactor than in the shake flask experiments. A maximum laccase yield of 392.9 U was observed within 144 h of the fermentation period with complete glucose depletion.  相似文献   
996.
997.
Bifocal is a putative cytoskeletal regulator and a Protein phosphatase-1 (PP1) interacting protein that mediates normal photoreceptor morphology in Drosophila. We show here that Bif and PP1-87B as well as their ability to interact with each other are required for photoreceptor growth cone targeting in the larval visual system. Single mutants for bif or PP1-87B show defects in axonal projections in which the axons of the outer photoreceptors bypass the lamina, where they normally terminate. The data show that the functions of bif and PP1-87B in either stabilizing R-cell morphology (for Bif) or regulating the cell cycle (for PP1-87B) can be uncoupled from their function in visual axon targeting. Interestingly, the axon targeting phenotypes are observed in both PP1-87B mutants and PP1-87B overexpression studies, suggesting that an optimal PP1 activity may be required for normal axon targeting. bif mutants also display strong genetic interactions with receptor tyrosine phosphatases, dptp10d and dptp69d, and biochemical studies demonstrate that Bif interacts directly with F-actin in vitro. We propose that, as a downstream component of axon signaling pathways, Bif regulates PP1 activity, and both proteins influence cytoskeleton dynamics in the growth cone of R cells to allow proper axon targeting.  相似文献   
998.
999.
Sequestosome 1/p62 is a scaffolding protein with several interaction modules that include a PB1 dimerization domain, a TRAF6 (tumor necrosis factor receptor-associated factor 6) binding site, and a ubiquitin-associating (UBA) domain. Here, we report that p62 functions to facilitate K63-polyubiquitination of TRAF6 and thereby mediates nerve growth factor-induced activation of the NF-kappaB pathway. In brain of p62 knock-out mice we did not recover polyubiquitinated TRAF6. The UBA domain binds polyubiquitin chains and deletion of p62-UBA domain or mutation of F406V within the ubiquitin binding pocket of the UBA domain abolished TRAF6 polyubiquitination. Likewise, deletion of p62 N-terminal dimerization domain or the TRAF6 binding site had similar effects on both polyubiquitination and oligomerization of TRAF6. Nerve growth factor treatment of PC12 cells induced TRAF6 polyubiquitination along with formation of a p62-TRAF6-IKKbeta-PKC iota signal complex, while inhibition of the p62/TRAF6 interaction had an opposite effect. These results provide evidence for a mechanism whereby p62 serves to regulate the NF-kappaB pathway.  相似文献   
1000.
Ribosome-inactivating proteins having antitumor and immunomodulatory properties constitute the active principle of widely used mistletoe therapy in Europe. This is the first report of the four isoforms of Himalayan mistletoe ribosome-inactivating proteins (HmRips) from Viscum album parasitized on wild apple inhabiting NW Himalayas. HmRips were purified by affinity chromatography and four isoforms were separated by ion-exchange chromatography. HmRip 1, 2, 3, and 4 have isoelectric points of 6.6, 6.1, 5.2, and 4.7, respectively. Disulfide linked toxin and lectin subunits of HmRip 1 and 2 isoforms have molecular weights of 28 and 34kDa while those of HmRip 3 and 4 have 28 and 32kDa. The isoforms lacked blood group specificity and showed positive activity with seven mammalian erythrocyte types but did not show any activity with avian erythrocyte type. Lectin activity of HmRips remained unchanged for a wide range of temperatures (0-65 degrees C) and pH (3-9). Unlike other type II Rips, the HmRip 1, 2, and 4 showed unique affinity towards l-rhamnose, meso-inositol, and l-arabinose while HmRip 3 has specificity to gal/galNAc. Sugar binding studies with 22 sugars also suggested that the C-4 hydroxyl of galactose might be the critical site involved in sugar binding of HmRips. Type II Rips are known to be galactoside specific and do not have affinity for l-rhamnose and meso-inositol. However, HmRip 1, 2, and 4 having equal affinity for galactose and l-rhamnose do not strictly fit into any of the four structural classes of the lectins and represent a new class of type II Rips and plant lectins.  相似文献   
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