Norepinephrine Regulation of Ventromedial Hypothalamic Nucleus Astrocyte Glycogen Metabolism

The catecholamine norepinephrine (NE) links hindbrain metabolic-sensory neurons with key glucostatic control structures in the brain, including the ventromedial hypothalamic nucleus (VMN). In the brain, the glycogen reserve is maintained within the astrocyte cell compartment as an alternative energy source to blood-derived glucose. VMN astrocytes are direct targets for metabolic stimulus-driven noradrenergic signaling due to their adrenergic receptor expression (AR). The current review discusses recent affirmative evidence that neuro-metabolic stability in the VMN may be shaped by NE influence on astrocyte glycogen metabolism and glycogen-derived substrate fuel supply. Noradrenergic modulation of estrogen receptor (ER) control of VMN glycogen phosphorylase (GP) isoform expression supports the interaction of catecholamine and estradiol signals in shaping the physiological stimulus-specific control of astrocyte glycogen mobilization. Sex-dimorphic NE control of glycogen synthase and GP brain versus muscle type proteins may be due, in part, to the dissimilar noradrenergic governance of astrocyte AR and ER variant profiles in males versus females. Forthcoming advances in the understanding of the molecular mechanistic framework for catecholamine stimulus integration with other regulatory inputs to VMN astrocytes will undoubtedly reveal useful new molecular targets in each sex for glycogen mediated defense of neuronal metabolic equilibrium during neuro-glucopenia.     

强化生物除磷动态模型研究进展

概述了国内外强化生物除磷(EBPR)动态模型的研究进展,主要介绍了其中较成熟的ASM模型和代谢模型,并对这两类模型中的代表模型的运用条件、优缺点进行了评述.在此基础上指出了目前EBPR模型发展中存在的共性问题,并提出:代谢/ASM复合模型和杂交模型是EBPR模型未来发展的方向,但完善的EBPR模型的建立最终还要依赖于对EBPR代谢机理的透彻研究.     

功能饮料抗疲劳作用的实验研究

目的：研究功能饮料的抗疲劳作用。方法：将雄性昆明小鼠按体重随机分为4组：空白对照组和12.5、25、75mL/（kg·bw）3个剂量组。在给予受试物30d后测定各组的小鼠负重游泳的持续时间,血乳酸水平（游泳前、游泳后0min、游泳后30min值）、血清尿素氮,以及肝糖原含量的变化。结果：25、75mL/（kg·bw）剂量的功能饮料能够显著延长小鼠的游泳时间（p〈0.05）,降低了小鼠血清中的乳酸、尿素氮含量（p〈0.05或p〈0.01）;75mL/（kg·bw）剂量的功能饮料显著增加小鼠的肝糖原含量（p〈0.01）。结论：功能饮料具有抗疲劳作用。     

Inhibitory mode of N-phenyl-4-pyrazolo[1,5-b] pyridazin-3-ylpyrimidin-2-amine series derivatives against GSK-3: molecular docking and 3D-QSAR analyses

Glycogen synthase kinase 3 (GSK-3) inhibition is an important research topic because of its wide range of associated health implications. The interaction mode of a series of N-phenyl-4-pyrazolo[1,5-b]pyridazin-3-ylpyrimidin-2-amine compounds with human GSK-3 has been studied using molecular docking and 3D-QSAR approaches. In the 3D-QSAR studies, the molecular alignment and conformation determination are so important that they affect the success of a model. Flexible docking (AutoDock3.0.5) was used for the determination of 'active' conformation and molecular alignment. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used to develop 3D-QSAR models of 80 N-phenyl-4-pyrazolo[1,5-b]pyridazin-3-ylpyrimidin-2-amine compounds. The r(2) values were 0.870 and 0.861 for CoMFA and CoMSIA models, respectively. The predictive ability of these models was validated by 10 compounds of the test set. Mapping these models back to the topology of the active site of GSK-3 led to a better understanding of the vital N-phenyl-4-pyrazolo[1,5-b]pyridazin-3-ylpyrimidin-2-amines-GSK-3 interactions. The results demonstrate that combination of ligand-based and receptor-based modeling is a powerful approach to build 3D-QSAR models. The interaction mode from this study may be helpful for the design of a novel inhibitor and guide the selection of candidate sites for further experimental studies on site-directed mutagenesis.     

枸杞原汁抗疲劳作用的研究

目的：研究枸杞原汁对小鼠的抗疲劳作用。方法：120只SPF级昆明种雌性小鼠平均分成4组,其中宁夏鲜枸杞原汁分10,20,30ml／（kg·d）三个剂量组给小鼠灌胃,对照组给等剂量生理盐水,共21天。最后一天喂养后,小鼠游泳造成疲劳,测定运动耐力、肝糖原、血乳酸（LAC）、血尿素氮（BUN）等指标。结果：枸杞原汁均能明显延长小鼠负重游泳时间,明显提高小鼠运动后体内肝糖原的含量,降低血尿素氮（BUN）和血乳酸（LAC）的含量。结论：枸杞原汁具有良好的抗疲劳作用。     

刺参对运动小鼠抗疲劳作用的研究

研究北方养殖刺参的主要活性成分和对运动小鼠抗疲劳的作用。结果表明：养殖刺参体壁富含酸性黏多糖、胶原蛋白、活性氨基酸和活性脂质等多种活性成分,能提高小鼠负重游泳能力、肝糖元含量和安静状态下小鼠血红蛋白含量,保持运动小鼠血红蛋白水平稳定,显著降低运动小鼠血乳酸的生成,促进运动后血乳酸的消除,加速运动血清尿素氮的清除。说明养殖刺参具有显著的抗疲劳和提高运动耐力的作用。     

Strategic finishing feeding as a tool in the control of pork quality

A standard diet and two finishing feeding strategies known to reduce muscle glycogen stores were investigated in combination with exercise immediately prior to slaughter in pigs. The objective was to determine the influence of muscle glycogen at slaughter on temperature and pH in post-mortem muscle, the colour, drip loss and Warner–Bratzler shear force of the meat. The muscle glycogen stores were reduced by strategic finishing feeding. In general, pH_{45 min} was higher in muscles from strategically fed pigs compared with control pigs. Exercise also resulted in higher pH_{45 min} in control pigs compared to non-exercised control pigs, while the opposite was seen in muscles from strategically fed pigs. Exercise resulted in higher muscle temperatures in the carcasses irrespective of feeding strategy. pH_{24 h} were higher in M. biceps femoris and M. semimembranosus from exercised, strategically fed pigs compared with the corresponding controls. In contrast, irrespective of feeding strategy no difference in pH_{24 h} was registered in the meat of non-exercised pigs. Drip loss was lower in meat of strategically fed pigs compared with meat of control pigs. Moreover the drip loss was lowest in the meat of non-exercised pigs. The present study shows that strategic finishing feeding has high potential for the control of pork quality.     

Glycogen autophagy

Glycogen autophagy, which includes the sequestration and degradation of cell glycogen in the autophagic vacuoles, is a selective process under conditions of demand for the massive hepatic production of glucose, as in the postnatal period. It represents a link between autophagy and glycogen metabolism. The formation of autophagic vacuoles in the hepatocytes of newborn animals is spatially and biochemically related to the degradation of cell glycogen. Many molecular elements and signaling pathways including the cyclic AMP/cyclic AMP-dependent protein kinase and the phosphoinositides/TOR pathways are implicated in the control of this process. These two pathways may converge on the same target to regulate glycogen autophagy.     

Yeast PIG Genes: PIG1 Encodes a Putative Type 1 Phosphatase Subunit that Interacts with the Yeast Glycogen Synthase Gsy2p

The biosynthesis of glycogen involves multiple proteins that associate with each other and the glycogen macromolecule. In efforts to understand the nature of these proteins, a two-hybrid screen was undertaken to detect proteins able to interact with Gsy2p, a major form of glycogen synthase in Saccharomyces cerevisiae. Two positives expressed proteins derived from genes designated PIG1 and PIG2, on chromosomes XIIR and IXL respectively. PIG1 codes for a protein with 38% identity over a 230 residue segment to Gac1p, a protein thought to be a type 1 protein phosphatase targeting subunit whose loss impairs glycogen synthesis. Pig2p has 30% identity to the protein corresponding to an open reading frame, YER054, on chromosome V. Deletion of PIG1 on its own had little effect on glycogen storage but, in combination with loss of GAC1, caused a more severe glycogen-deficient phenotype than seen in gac1 mutants. This result is consistent with Pig1p being functionally related to Gac1p and we propose that Pig1p may be a type 1 phosphatase regulatory subunit. Delection of PIG2, YER054, or both genes together caused no detectable change in glycogen metabolism under the conditions tested. Gac1p, Pig1p, Pig2p and the YER054p are the only four proteins coded by the yeast genome that share a conserved segment of ∼25 residues, designated the GVNK motif, that is identifiable also in R_GI, the mammalian type 1 phosphatase targeting subunit. © 1997 by John Wiley & Sons, Ltd.