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Shu Lin

Publications and source records attributed to Shu Lin.

10 recordsLinked to original sources

Chitinase gene diversity at a deep sea station of the east Pacific nodule province.

The Pacific nodule province covered about 4.5 million km(2) in the east tropical Pacific with an abundance of polymetallic nodules at the seafloor. In view of the environmental protection and resource preservation, the survey of biodiversity was important during the reconnaissance and exploitation in this area. As one of the important component of the deep sea ecosystem, the microbial community in the Pacific nodule province was still largely unknown. The chitinolytic bacteria diversity in deep-sea sediment of a station within the Pacific nodule province was examined by molecular technology. A total of 18 chitinase genes were detected by a set of degenerate PCR primer specific for chiA gene fragment of family 18 chitinase. Most of them belonged to the Serratia-like chitinase. Eight genes had different amino acid sequences in the conserved motif, encompassing the catalytic site among the ChiA protein of family 18 glycosyl hydrolases, and clustered in an independent clade on the phylygenetic tree.

Amino Acid Sequence↗

Neuropeptide Y (NPY) Y4 receptor selective agonists based on NPY(32-36): development of an anorectic Y4 receptor selective agonist with picomolar affinity.

We have previously shown [Cys-Trp-Arg-Nva-Arg-Tyr-NH(2)](2), 1, to be a moderately selective neuropeptide Y (NPY) Y(4) receptor agonist. Toward improving the selectivity and potency for Y(4) receptors, we studied the effects of dimerizing H-Trp-Arg-Nva-Arg-Tyr-NH(2) using various diamino-dicarboxylic acids containing either di-, tri-, or tetramethylene spacers. These parallel dimers, 2A, 2B, 3, 4A, and 4B, and the corresponding linear tandem dimer and trimer analogues, 5 and 6, had enhanced selectivity and affinity for Y(4) receptors compared to 1 (Table 1). Substitution of Trp and Nva with Tyr and Leu, respectively, as in 2,7-d/l-diaminosuberic acid derivatized dimer, 7, resulted in a superior Y(4) selective agonist with picomolar affinity. Intraperitoneal (ip) injection of 7 potently inhibited food intake in fasted mice. Moreover, 7 (ip) inhibited the food intake in wild-type mice and not in Y(4)(-/-) knock-out mice, confirming that the actions of 7 on food intake are not due to global effects, but specifically mediated Y(4) receptors.

Animals↗

Distribution of prodynorphin mRNA and its interaction with the NPY system in the mouse brain.

Using radioactive in situ hybridisation, the distribution of prodynorphin mRNA in the brains of C57Bl/6 mice was systemically investigated, and double-labelling in situ hybridisation was used to determine the extent to which neuropeptide Y (NPY) and prodynorphin mRNAs were co-expressed. Our results demonstrate that prodynorphin mRNA expression in the mouse brain is localised at specific subregions of the olfactory bulb, cortex, hippocampus, amygdala, basal ganglia, thalamus, hypothalamus, mesencephalon and myelencephalon. Among the regions displaying the most intense labelling were the olfactory tubercle, lateral septum (LS), caudate putamen (Cpu), central amygdaloid nucleus (Ce), paraventricular hypothalamic nucleus (PVN), supraoptic nucleus (SO), lateral hypothalamic area (LHA), ventromedial hypothalamic nucleus (VMH), lateral reticular nucleus (LRt) and solitary tract nucleus (NTS). In the arcuate nucleus of the hypothalamus (Arc), double-labelling in situ hybridisation revealed that prodynorphin expressing neurons also contained NPY mRNA, with a co-localisation rate of approximately 88% in the lateral part of the Arc, and 79% in the dorsal part of the Arc, respectively, suggesting potential overlapping functions of these two neurotransmitters in feeding type behaviour.

Animals↗

Y2Y4 receptor double knockout protects against obesity due to a high-fat diet or Y1 receptor deficiency in mice.

Neuropeptide Y receptors are critical regulators of energy homeostasis, but the functional interactions and relative contributions of Y receptors and the environment in this process are unknown. We measured the effects of an ad libitum diet of normal or high-fat food on energy balance in mice with single, double, or triple deficiencies of Y1, Y2, or Y4 receptors. Whereas wild-type mice developed diet-induced obesity, Y2Y4 double knockouts did not. In contrast, Y1 knockout or Y1Y2 or Y1Y4 receptor double knockout mice developed an exacerbated diet-induced obesity syndrome. Remarkably, the antiobesity effect of Y2Y4 deficiency was stronger than the obesogenic effect of Y1 deficiency, since Y1Y2Y4 triple knockouts did not develop obesity on the high-fat diet. Resistance to diet-induced obesity in Y2Y4 knockouts was associated with reduced food intake and improved glucose tolerance in the absence of changes in total physical activity. Fecal concentration of free fatty acids was significantly increased in Y2Y4 knockouts in association with a significantly reduced bile acid pool and marked alterations in intestinal morphology. In addition, hypothalamic proopiomelanocortin expression was decreased in diet-induced obesity (in both wild-type and Y1 receptor knockout mice) but not in obesity-resistant Y2Y4 receptor knockout mice fed a high-fat diet. Therefore, deletion of Y2 and Y4 receptors synergistically protects against diet-induced obesity, at least partially via changes in food intake and hypothalamic proopiomelanocortin expression.

Animals↗

[Preparation of cytarabine nanoparticle and study on the drug releasing mechanism].

Cytarabine nanoparticle was prepared through emulsion polymerization method, and its releasing properties were studied. The results showed that releasing principle complied with biexponential equation and had characteristics of sustained releasing. The pharmacokinetics in rabbits complied with two-department model. Compared with cytarabine injection, cytarabine nanoparticle had prolonged t 1/2beta and MRT and reduced CL, which showed nanoparticle could significantly prolong the retention time of Ara-C and possess significant sustained releasing character.

Animals↗

Y1 receptors regulate aggressive behavior by modulating serotonin pathways.

Neuropeptide Y (NPY) is pivotal in the coordinated regulation of food intake, growth, and reproduction, ensuring that procreation and growth occur only when food is abundant and allowing for energy conservation when food is scant. Although emotional and behavioral responses from the higher brain are known to be involved in all of these functions, understanding of the coordinated regulation of emotion/behavior and physiological functions is lacking. Here, we show that the NPY system plays a central role in this process because ablation of the Y1 receptor gene leads to a strong increase in territorial aggressive behavior. After exposure to the resident-intruder test, expression of c-fos mRNA in Y1-knockout mice is significantly increased in the medial amygdala, consistent with the activation of centers known to be important in regulating aggressive behavior. Expression of the serotonin [5-hydroxytryptamine (5-HT)] synthesis enzyme tryptophan hydroxylase is significantly reduced in Y1-deficient mice. Importantly, treatment with a 5-HT-1A agonist, (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide, abolished the aggressive behavior in Y1-knockout mice. These results suggest that NPY acting through Y1 receptors regulates the 5-HT system, thereby coordinately linking physiological survival mechanisms such as food intake with enabling territorial aggressive behavior.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

NPY and Y receptors: lessons from transgenic and knockout models.

Neuropeptide Y (NPY) in the central nervous system is a major regulator of food consumption and energy homeostasis. It also regulates blood pressure, induces anxiolysis, enhances memory retention, affects circadian rhythms and modulates hormone release. Five Y receptors (Y1, Y2, Y4, Y5 and Y6) are known to mediate the action of NPY and its two other family members, peptide YY (PYY) and pancreatic polypeptide (PP). Increased NPY signaling due to elevated NPY expression in the hypothalamus leads to the development of obesity and its related phenotypes, Type II diabetes and cardiovascular disease. Dysregulation in NPY signaling also causes alterations in bone formation, alcohol consumption and seizure susceptibility. The large number of Y receptors has made it difficult to delineate their individual contributions to these physiological processes. However, recent studies analysing NPY and Y receptor overexpressing and knockout models have started to unravel some of the different functions of these Y receptors. Particularly, the use of conditional knockout models has made it possible to pinpoint a specific function to an individual Y receptor in a particular location.

Animals↗

[Study on relative bioavailability of aspirin in afenca tablet].

Salicylic acid is a kind of active metabolite of aspirin in vivo. In this study, its concentration in plasma was detected by RP-HPLC after twenty four healthy male volunteers were given each a single dose of oral Afenca test and reference preparations. The experiment data were calculated with 3P97 program. The results were analyzed by ANOVA and two- and one-sided t tests. The relative bioavailability of salicylic acid was 105.36% +/- 14.15%; AUC0-T of salicylic acid of test and reference preparations were 103.10 +/- 11.92 micrograms.h/ml and 98.45 +/- 13.49 micrograms.h/ml respectively; Tmax were 1.5 +/- 0.5 h and 1.5 +/- 0.5 h; Cmax were 19.31 +/- 2.47 micrograms/ml and 18.95 +/- 2.49 micrograms/ml. Bioequivalent evaluation of two preparations by analyzing with two- and one-sided t tests showed that the two preparations were bioequivalent on the basis of salicylic acid (t1 > or = t1-0.05(22), t2 > or = t1-0.06(22)).

Administration, Oral↗

[Studies on chemical constituents in fruits of Tibetan medicine Phyllanthus emblica].

OBJECTIVE: To investigate the chemical constituents of Tibetan medicine Phyllanthus emblica. METHOD: Various chromatographic techniques were employed for isolation and purification of the constituents, and the structures were elucidated by chemical and spectral analyses. RESULT: 11 compounds were isolated and identified as gallic acid (I), ellagic acid (II), 1-O-galloyl-beta-D-glucose (III), 3,6-di-O-galloyl-D-glucose (IV), chebulinic acid (V), quercetin (VI), chebulagic acid (VII), corilagin (VIII), 3-ethylgallic acid (3-ethoxy-4,5-dihydroxy-benzoic acid, IX), isostrictiniin (X), 1,6-di-O-galloyl-beta-D-glucose (XI). CONCLUSION: 3-Ethylgallic acid (3-ethoxy-4,5-dihydroxy-benzoic acid) is a novel compound, and isostrictiniin was found from P. emblica for the first time.

Ellagic Acid↗