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991.
Triterpene saponins and iridoid glucosides from galium rivale   总被引:2,自引:0,他引:2  
Three new glycosides of the oleanene-type triterpenes, rivalosides C-E (1-3), along with three known triterpene saponins, momordin IIb (4) and rivalosides A-B (5-6), and five known iridoid glucosides: monotropein, scandoside, deacetylasperulosidic acid, geniposidic acid and asperulosidic acid, were isolated from aerial parts of Galium rivale. The structures of the new compounds were elucidated by spectral methods and chemical means as 2alpha-acetoxy-3alpha, 19alpha-dihydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1--> 6)-beta-D-glucopyranoside, 2alpha,3alpha, 19alpha-trihydroxy-olean- 12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranoside and 3-O-beta-D-glucuronopyranosyl-24-hydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranoside, for rivalosides C-E, respectively. The taxonomic significance of the rivalosides in G. rivale was discussed.  相似文献   
992.
Here, we report the sequencing and classification of Nyamanini virus (NYMV) and Midway virus (MIDWV), two antigenically related viruses that were first isolated in 1957 and 1966, respectively. Although these viruses have been cultured multiple times from cattle egrets, seabirds, and their ticks, efforts to classify them taxonomically using conventional serological and electron microscopic approaches have failed completely. We used a random shotgun sequencing strategy to define the genomes of NYMV and MIDWV. Contigs of 11,631 and 11,752 nucleotides, representing the complete genome of NYMV and the near-complete genome of MIDWV, respectively, were assembled. Each virus genome was predicted to carry six open reading frames (ORFs). BLAST analysis indicated that only two of the ORF proteins of each virus, the putative nucleocapsid and polymerase, had detectable sequence similarity to known viral proteins. Phylogenetic analysis of these ORF proteins demonstrated that the closest relatives of NYNV and MIDWV are negative-stranded-RNA viruses in the order Mononegavirales. On the basis of their very limited sequence similarity to known viruses, we propose that NYMV and MIDWV define a novel genus, Nyavirus, in this order.Nyamanini virus (NYMV) was first isolated in 1957 from a cattle egret (Bubulcus ibis) in South Africa (24). It has subsequently been isolated in Nigeria, Egypt, India, and Thailand from cattle egrets and Argas walkerae ticks (14, 16, 24). Although there has been no recognized human infection or disease associated with NYMV, suckling mice succumbed to NYMV infection 7 or 8 days after intracerebral inoculation (14). NYMV has not been definitively characterized or classified to date (10).Midway virus (MIDWV) was first isolated in 1966 from seabird ticks of two species [Ornithodoros (Alectorobius) spp.] collected on the Midway, Kure, and Manana islands in the Central Pacific and from northern Honshu, Japan. In addition, on Aomatsushima Island, nestling seabirds of two seabird species, Larus crassirostris and Nycticorax nycticorax, were found to have antibody to MIDWV. This virus is pathogenic for newborn Swiss mice but not 4-week-old Swiss mice injected intracranially. Also, the virus is cytopathic in BHK-21 cells and produces plaques in Vero cells. Efforts to classify MIDWV have revealed only that MIDWV is antigenically related to NYMV in cross-box complement fixation (CF) assays (22).To date, conventional approaches, such as serological analysis and electron microscopy (EM), have not yielded definitive characterization of MIDWV or NYMV. Heretofore, it was not known whether MIDWV and NYMV are DNA viruses or RNA viruses or to which virus family they belong. In this paper, we describe the application of unbiased high-throughput sequencing to define the genome sequences of NYMV and MIDWV. By analysis of their genomes, NYMV and MIDWV were determined to be negative-stranded RNA viruses highly divergent from all known viruses but most closely related to viruses in the order Mononegavirales. On the basis of the analysis presented herein, we propose that NYMV and MIDWV define a novel taxon within the order Mononegavirales.  相似文献   
993.
The genus Cleptes Latreille, 1802 from China is revised and illustrated for the first time. Seventeen species of Cleptes are recorded. Nine species are new to science, Cleptes albonotatus sp. n., Cleptes eburnecoxis sp. n., Cleptes flavolineatus sp. n., Cleptes helanshanus sp. n., Cleptes niger sp. n., Cleptes shengi sp. n., Cleptes sinensis sp. n., Cleptes tibetensis sp. n., and Cleptes villosus sp. n.,and two species are reported as new to China, Cleptes metallicorpus Ha, Lee & Kim, 2011, and Cleptes seoulensis Tsuneki, 1959.  相似文献   
994.
SR proteins are essential pre-mRNA splicing factors that have been shown to bind a number of exonic splicing enhancers where they function to stimulate the splicing of adjacent introns. Members of the SR protein family contain one or two N-terminal RNA binding domains, as well as a C-terminal arginine–serine (RS) rich domain. The RS domains mediate protein–protein interactions with other RS domain containing proteins and are essential for many, but not all, SR protein functions. Hybrid proteins containing an RS domain fused to the bacteriophage MS2 coat protein are sufficient to activate enhancer-dependent splicing in HeLa cell nuclear extract when bound to the pre-mRNA. Here we report progress towards determining the protein sequence requirements for RS domain function. We show that the RS domains from non-SR proteins can also function as splicing activation domains when tethered to the pre-mRNA. Truncation experiments with the RS domain of the human SR protein 9G8 identified a 29 amino acid segment, containing 26 arginine or serine residues, that is sufficient to activate splicing when fused to MS2. We also show that synthetic domains composed solely of RS dipeptides are capable of activating splicing, although their potency is proportional to their size.  相似文献   
995.
Five isolates of Trichoderma atroviride and one isolate each of T. virens, T. harzianum and T. cerinum were tested for in vivo biological control of white root rot of avocado (Rosellinia necatrix). Five of these Trichoderma isolates were previously selected as possible biological control agents on the basis of their capacity to control the disease and high levels of colonization of the avocado rhizoplane. Combinations of the five selected isolates were evaluated on cellophane for compatibility with each other and T. virens CH 303 was eliminated because of a high incompatibility with other Trichoderma isolates. The four remaining isolates, all T. atroviride, were tested singly and in combination for their capacity to control avocado white root rot. Isolate CH 304.1 provided the highest levels of control when tested singly or in combination with isolate CH 101.  相似文献   
996.
The mobility and dispersal of organisms affect population genetics and dynamics, and consequently affect persistence and the risk of extinction. Thus, it is important to understand how organisms move in the fragmented landscapes in order to manage populations and predict the effects of habitat changes on species persistence. This study evaluated the functional connectivity of an orchid bee (Eulaema atleticana Nemésio, 2009) with a high fidelity to forest habitats in the Brazilian Atlantic Forest Corridor by analyzing genetic diversity, spatial genetic structure, and gene flow estimated from microsatellite and mitochondrial markers. Genetic diversity was not correlated with area of the forest fragments, or with forest isolation. At the mosaic scale, Eulaema atleticana showed no significant or low genetic differentiation, indicating genetic homogeneity among forest fragments. A previous field study indicated that Eulaema atleticana was one of the most sensitive Euglossina bees to forest fragmentation but the present molecular analyses demonstrates that current gene flow is sufficient to maintain genetic variability at the mosaic scale.  相似文献   
997.
The phytopathogenic bacterium Xanthomonas axonopodis pv. citri is responsible for the canker disease affecting citrus plants throughout the world. Here, we have evaluated the role of bacterial attachment and biofilm formation in leaf colonization during canker development on lemon leaves. Crystal violet staining and confocal laser scanning microscopy analysis of X. axonopodis pv. citri strains expressing the green fluorescent protein were used to evaluate attachment and biofilm formation on abiotic and biotic (leaf) surfaces. Wild-type X. axonopodis pv. citri attached to and formed a complex, structured biofilm on glass in minimal medium containing glucose. Similar attachment and structured biofilm formation also were seen on lemon leaves. An X. axonopodis pv. citri gumB mutant strain, defective in production of the extracellular polysaccharide xanthan, did not form a structured biofilm on either abiotic or biotic surfaces. In addition, the X. axonopodis pv. citri gumB showed reduced growth and survival on leaf surfaces and reduced disease symptoms. These findings suggest an important role for formation of biofilms in the epiphytic survival of X. axonopodis pv. citri prior to development of canker disease.  相似文献   
998.
The aim of this work was to analyze the effect of carbamazepine (CBZ) on sleep patterns and on “head and body shakes” and to determine the role of serotonin (5-HT) in a model of kainic-induced seizures. Thirty male Wistar rats (280–300 g) were used for polygraphic sleep recording. After a basal recording, the rats were allocated into three groups: kainic acid-treated animals (KA; 10 mg/kg; n = 10), carbamazepine-treated animals (CBZ; 30 mg/kg; n = 10) and animals injected with KA 30 min after pretreatment with CBZ (CBZ + KA; n = 10). Polygraphic recordings were performed for 10 h for 3 days, with the exception of the CBZ group, which were observed for 1 day. In order to measure the head and body shakes that occurred over that time, a behavioral assessment was performed in two additional groups of KA (n = 10) and CBZ + KA (n = 10) animals. After 10 h of behavioral assessment, the rats were sacrificed, and the levels of 5-HT and 5-hydroxy-indol-acetic acid (5-HIAA) were analyzed. We compared these findings with the results from a group of rats without pharmacological intervention (n = 10). All of the recordings were performed from 08:00 to 18:00 h. Data analysis: the electrographic parameters, head and body shake counting and monoamine concentrations were analyzed by an ANOVA test. Differences of *p ≤ 0.01 and **p ≤ 0.001 were considered statistically significant. Our results showed that CBZ exerted a protective effect on sleep pattern alterations induced by KA, which when administered alone caused a complete inhibition of sleep for the first 10 h after administration. Although there was a reduction in the amount of sleep after the administration of KA in CBZ-pretreated animals, sleep inhibition was incomplete. In addition, CBZ decreased the frequency of head and body shakes by 60% as compared to KA. The 5-HT and 5-HIAA levels in the pons were increased in the KA and KA + CBZ groups. Our conclusion is that in addition to decreasing seizure intensity, CBZ facilitates the partial recovery of sleep. These results suggest that CBZ provides neuro-protective effects on sleep and against seizures.  相似文献   
999.
Live-cell imaging methods were used to study microtubule dynamics in the apical regions of leading hyphae and germ tubes of Neurospora crassa expressing beta-tubulin-GFP. Microtubule polymerization rates in hyphae of N. crassa were much faster than those previously reported in any other eukaryotic organism. In order to address the roles of motor proteins in microtubule dynamic instability in N. crassa, the microtubule-motor mutant strains, Deltankin and ro-1, were examined. Polymerization and depolymerization rates in leading hyphae of these strains were reduced by one half relative to the wild type. Furthermore, microtubules in germ tubes of wild type and microtubule-motor mutants exhibited similar dynamic characteristics as those in hyphae of mutant strains. Small microtubule fragments exhibiting anterograde and retrograde motility were present in leading hyphae of all strains and germ tubes of wild-type strains. Our data suggest that microtubule motors play important roles in regulating microtubule dynamic instability in leading hyphae but not in germ tubes.  相似文献   
1000.
Both prolactin (PRL) and TGF-beta regulate cell survival in mammary epithelial cells, but their mechanisms of interactions are not known. In primary mammary epithelial cells and the HC11 mouse mammary epithelial cell line, PRL prevented TGF-beta-induced apoptosis, as measured by terminal deoxynucleotidyltransferase dUTP nick-end labeling staining and caspase-3 activation. This effect depended on phosphatidyl inositol triphosphate kinase (PI3K). PI3K activates a downstream serine/threonine kinase, Akt; therefore, we investigated the role of Akt in the interaction between PRL and TGF-beta signaling. Akt activity was inhibited by TGF-beta over a 20- to 60-min time course. In TGF-beta-treated cells, PRL disinhibited Akt in a PI3K-dependent manner. Expression of dominant negative Akt blocked the protective effect of PRL in TGF-beta-induced apoptosis. Transgenic mice overexpressing a dominant-negative TGF-beta type II receptor (DNIIR) in the mammary epithelium undergo hyperplastic alveolar development, and this effect was PRL dependent. Involution in response to teat sealing was slowed by overexpression of DNIIR; furthermore, Akt and forkhead phosphorylation increased in the sealed mammary glands of DNIIR mice. Thus, Akt appears to be an essential component of the interaction between PRL and TGF-beta signaling in mammary epithelial cells both in vitro and in vivo.  相似文献   
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