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751.
Metabolism of small RNAs in cultured human cells 总被引:2,自引:0,他引:2
752.
The response of the SON to various forms of stress is well documented. However, the effect of operative stress, which is a common and important clinical event requiring the mediation of vasopressin, has largely escaped attention. The present report describes the ultrastructural changes in the neurons of the caudal (retrochiasmatic) part of the SON following a deepseated linear incision on the dorsum of the rat. The observations were confirmed to the first forty-eight hours after trauma. At 24-hours post-operatively, a marked depletion of the neurosecretory granules was observed. This was associated with a proliferation of the granular and smooth endoplasmic reticulum, Golgi cisternae and ribosomes. A few of the neurosecretory granules were seen to lie in the close vicinity of the Golgi complexes. At 48-hours after trauma, these features persisted. In addition, an accumulation of neurosecretory granules was conspicuous in some axon pre-terminals. From the above findings, it is suggested that an increased demand for vasopressin during the early postoperative period is met by the supraoptic neurons by a liberation of their neurosecretory contents. An attempt at replenishment of the latter is evidenced by a proliferation in the membrane components and ribosomes. The pooling of neurosecretory granules in occasional axon pre-terminals may indicate an imbalance in the synthesis-secretion coupling of vasopressin. 相似文献
753.
Cellular and chloroplast lipids of the leaves of Mimosa pudica have been analysed. Qualitatively the total lipid composition of this plant is similar to that reported for the photosynthetic tissues of other plants. Chloroplast lipids show some resemblance to those of algae. The cerebroside fraction of both leaves and chloroplasts contains a polyunsaturated fatty acid (20:4ω3) and a long chain sphingosine base whose Rf value coincides with that from ox brain cerebroside and not with that of phytosphingosine from spinach. 相似文献
754.
In this study isopod species of the Ross Sea were investigated. Literature until May 2008 was checked to provide an overview
of all known and described species in the Ross Sea. This species checklist was then enlarged through material of the 19th
Italica expedition in 2004. During this expedition for the first time a small mesh net (500 μm) was used. Nine thousand four hundred
and eighty one isopod specimens were collected during this expedition. Through this material the number of isopod species
in the Ross Sea increased from 42 to 117 species, which belong to 20 families and 49 genera. Fifty-six percentage of the isopods
species collected during the Italica expedition are new to science. The zoogeography of the 117 species was investigated. A non-transformed binary presence-absence
data matrix was constructed using the Bray–Curtis coefficient. The results were displayed in a cluster analysis and by nonmetric
multidimensional scaling (MDS). This paper gives a first insight into the occurrence and distribution of the isopod species
of the Ross Sea. 相似文献
755.
J P Spencer G Chowrimootoo R Choudhury E S Debnam S K Srai C Rice-Evans 《FEBS letters》1999,458(2):224-230
We have studied the perfusion of the jejunum and ileum in an isolated rat intestine model with flavonoids and hydroxycinnamates and the influence of glycosylation on the subsequent metabolism. Flavone and flavonol glucosides and their corresponding aglycones are glucuronidated during transfer across the rat jejunum and ileum and this glucuronidation occurs without the need for gut microflora. Furthermore, this suggests the presence of glycosidases as well as UDP-glucuronyl transferase in the jejunum. In contrast, quercetin-3-glucoside and rutin are mainly absorbed unmetabolised. The results suggest that the more highly reducing phenolics are absorbed predominantly as glucuronides (96.5%+/-4.6) of the amount absorbed, whereas monophenolic hydroxycinnamates and monophenolic B-ring flavonoids are less predisposed to glucuronidation and higher levels of aglycone (88.1%+/-10.1) are detected on absorption through both the jejunum and ileum. 相似文献
756.
Large-sized Barnacle Geese Branta leucopsis of both sexes had a higher probability of breeding successfully in any particular year and produced more goslings than did smaller birds. Large females paired at an earlier age, suggesting that they were preferred as mates and were likely to have entered the breeding population earlier. The relative sizes of the pair bond members also affected fitness. Most birds were able to maximize their breeding performance by mating with relatively similar sized partners; the greater the size disparity of mates, the lower the breeding performance. This supports the idea that compatibility of mates may be important in determining fitness of the pair. The success of different pair types was also affected by environmental conditions, with certain size combinations doing better in some years and poorly in other years. 相似文献
757.
A novel diterpene has been isolated from the stem bark of Xylopia quintasii and identified as 7β-acetoxytrachyloban-18-oic acid. The taxonomic si 相似文献
758.
Four diterpenes were isolated from the stem bark of Xylopia acutiflora and characterized as (?)-kauran-16α-ol, 7,8-acetoxy-(?)-kaur-16-en-19-oic acid, 15-oxo-(?)-kaur-16-en-19-oic acid, and 16α- hydroxy-(?)-kauran-19-oic acid. 相似文献
759.
Roseanne M. Lorenzana Aaron Y. Yeow Joan T. Colman Lara L. Chappell Harlal Choudhury 《人类与生态风险评估》2009,15(1):185-200
Major sources of arsenic exposure for humans are foods, particularly aquatic organisms, which are called seafood in this report. Although seafood contains a variety of arsenicals, including inorganic arsenic, which is toxic and carcinogenic, and arsenobetaine, which is considered nontoxic, the arsenic content of seafood commonly is reported only as total arsenic. A goal of this literature survey is to determine if generalizable values can be derived for the percentage of total arsenic in seafood that is inorganic arsenic. Generalizable values for percent inorganic arsenic are needed for use as default values in U.S. human health risk assessments of seafood from arsenic-contaminated sites. Data from the worldwide literature indicate the percent of inorganic arsenic in marine/estuarine finfish does not exceed 7.3% and in shellfish can reach 25% in organisms from presumably uncontaminated areas, with few data available for freshwater organisms. However, percentages can be much higher in organisms from contaminated areas and in seaweed. U.S. site-specific data for marine/estuarine finfish and shellfish are similar to the worldwide data, and for freshwater finfish indicate that the average percent inorganic arsenic is generally < 10%, but ranges up to nearly 30%. Derivation of nationwide defaults for percent inorganic arsenic in fish, shellfish, and seaweed collected from arsenic-contaminated areas in the United States is not supported by the surveyed literature. 相似文献
760.
A new steroidal alkaloid has been isolated from the leaves of Buxus papilosa. Its structure has been assigned as 1 on the basis of spectroscopic studies. 相似文献