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101.
We used a conditioned taste aversion test to assess whether PYY(3-36) reduces food intake by producing malaise. Two-hour IV infusion of PYY(3-36) (8, 15, and 30 pmol/kg/min) at dark onset in non-food-deprived rats produced a dose-dependent inhibition of feeding and a conditioned aversion to the flavored chow paired with PYY(3-36) infusion. In food-deprived rats, PYY(3-36) at 2 and 4 pmol/kg/min inhibited intake of a flavored saccharin solution without producing conditioned taste aversion, whereas higher doses (8 and 15 pmol/kg/min) inhibited saccharin intake and produced taste aversion. These results suggest that anorexic doses of PYY(3-36) may produce a dose-dependent malaise in rats, which is similar to that reported for PYY(3-36) infusion in humans. Previous studies have shown that PYY(3-36) potently inhibits gastric emptying, and that gut distention can produce a conditioned taste aversion. Thus, PYY(3-36) may produce conditioned taste aversion in part by slowing gastric emptying. 相似文献
102.
Di A Brown ME Deriy LV Li C Szeto FL Chen Y Huang P Tong J Naren AP Bindokas V Palfrey HC Nelson DJ 《Nature cell biology》2006,8(9):933-944
Acidification of phagosomes has been proposed to have a key role in the microbicidal function of phagocytes. Here, we show that in alveolar macrophages the cystic fibrosis transmembrane conductance regulator Cl- channel (CFTR) participates in phagosomal pH control and has bacterial killing capacity. Alveolar macrophages from Cftr-/- mice retained the ability to phagocytose and generate an oxidative burst, but exhibited defective killing of internalized bacteria. Lysosomes from CFTR-null macrophages failed to acidify, although they retained normal fusogenic capacity with nascent phagosomes. We hypothesize that CFTR contributes to lysosomal acidification and that in its absence phagolysosomes acidify poorly, thus providing an environment conducive to bacterial replication. 相似文献
103.
Szeto FL Reardon CA Yoon D Wang Y Wong KE Chen Y Kong J Liu SQ Thadhani R Getz GS Li YC 《Molecular endocrinology (Baltimore, Md.)》2012,26(7):1091-1101
Although vitamin D has been implicated in cardiovascular protection, few studies have addressed the role of vitamin D receptor (VDR) in atherosclerosis. Here we investigate the effect of inactivation of the VDR signaling on atherogenesis and the antiatherosclerotic mechanism of vitamin D. Low density lipoprotein receptor (LDLR)(-/-)/VDR(-/-) mice exhibited site-specific accelerated atherogenesis, accompanied by increases in adhesion molecules and proinflammatory cytokines in the aorta and cholesterol influx in macrophages. Macrophages showed marked renin up-regulation in the absence of VDR, and inhibition of renin by aliskiren reduced atherosclerosis in LDLR(-/-)/VDR(-/-) mice, suggesting that the renin-angiotensin system (RAS) promotes atherosclerosis in the absence of VDR. LDLR(-/-) mice receiving LDLR(-/-)/VDR(-/-) BMT developed larger lesions than LDLR(-/-) BMT controls. Moreover, LDLR(-/-) mice receiving Rag-1(-/-)/VDR(-/-) BMT, which were unable to generate functional T and B lymphocytes, still had more severe atherosclerosis than Rag-1(-/-) BMT controls, suggesting a critical role of macrophage VDR signaling in atherosclerotic suppression. Aliskiren treatment eliminated the difference in lesions between Rag-1(-/-)/VDR(-/-) BMT and Rag-1(-/-) BMT recipients, indicating that local RAS activation in macrophages contributes to the enhanced atherogenesis seen in Rag-1(-/-)/VDR(-/-) BMT mice. Taken together, these observations provide evidence that macrophage VDR signaling, in part by suppressing the local RAS, inhibits atherosclerosis in mice. 相似文献
104.
105.
Recently, there has been renewed interest in the role of reactive oxygen species (ROS), especially H(2)O(2), in wound healing. We previously showed that H(2)O(2) stimulates healing in a keratinocyte scratch wound model. In this paper, we used a more complex and physiologically relevant model that involves co-culturing primary keratinocytes and fibroblasts. We found that the two main cell types within the skin have different sensitivities to H(2)O(2) and to the widely used "antioxidant"N-acetyl-l-cysteine (NAC). Keratinocytes were very resistant to the toxicity of H(2)O(2) (250 and 500 μM) or NAC (5 mM). However, the viability of fibroblasts was decreased by both compounds. Using the co-culture model, we also found that H(2)O(2) increases re-epithelialization while NAC retards it. Our data further illustrate the possible role of ROS in wound healing and the co-culture model should be useful for screening agents that may influence the wound healing process. 相似文献
106.
107.
Yong Chao Lu Hui Chen Kin Lam Fok Lai Ling Tsang Mei Kuen Yu Xiao Hu Zhang Jing Chen Xiaohua Jiang Yiu Wa Chung Alvin Chun Hang Ma Anskar Yu Hung Leung He Feng Huang Hsiao Chang Chan 《Cell research》2012,22(10):1453-1466
Although HCO3− is known to be required for early embryo development, its exact role remains elusive. Here we report that HCO3− acts as an environmental cue in regulating miR-125b expression through CFTR-mediated influx during preimplantation embryo development. The results show that the effect of HCO3− on preimplantation embryo development can be suppressed by interfering the function of a HCO3−-conducting channel, CFTR, by a specific inhibitor or gene knockout. Removal of extracellular HCO3− or inhibition of CFTR reduces miR-125b expression in 2 cell-stage mouse embryos. Knockdown of miR-125b mimics the effect of HCO3− removal and CFTR inhibition, while injection of miR-125b precursor reverses it. Downregulation of miR-125b upregulates p53 cascade in both human and mouse embryos. The activation of miR-125b is shown to be mediated by sAC/PKA-dependent nuclear shuttling of NF-κB. These results have revealed a critical role of CFTR in signal transduction linking the environmental HCO3− to activation of miR-125b during preimplantation embryo development and indicated the importance of ion channels in regulation of miRNAs. 相似文献
108.
A major issue faced by breeders is how to effectively manage adverse correlations in breeding programs. We present results
of a Monte Carlo allele-based simulation of the changes in response and variance of response under adverse genetic correlations
by using the examples of two contrasting selection methods: the ‘Smith-Hazel’ selection index (SH) and independent culling
(IC). We assumed several gene models, which included linkage and antagonistic pleiotropy as the primary drivers of adverse
genetic correlations. The different behaviors of these selection methods allowed us to identify the mechanism behind the generation
of uncertainty under antagonistic trait selection: IC had the properties of stabilizing selection, while SH behaved more similar
to disruptive selection. Although SH outperformed IC in terms of genetic gain, this advantage happened at the cost of higher
variance of response and loss of heterozygosity. Using an optimum selection algorithm (OS) to prevent the loss of heterozygosity
through a constraint on inbreeding in SH/OS increased marginally the reliability, remaining still below that of IC under equal
conditions. However, SH/OS had lower inbreeding (ΔF) than IC for equivalent levels of genetic gain, so a compromise between
high selection reliability, low ΔF, and gain must be made by a breeder under antagonistic trait selection even with the use
of optimization tools. 相似文献
109.
Michael Stoehr Alvin Yanchuk Chang-Yi Xie Leopoldo Sanchez 《Tree Genetics & Genomes》2008,4(2):193-200
Sublines are used in the third-generation breeding and testing of coastal Douglas-fir in British Columbia, with the original
intent of selecting only one genotype per subline for production populations (e.g., seed orchards) to eliminate relatedness
among parents (therein called “1/SL”). We evaluated three additional selection scenarios that did not consider the subline
structure. One of the scenarios strictly selected on the basis of the highest breeding values of the trees (“TOP”); another
scenario used the TOP selections, but assigned the number of ramets per selection proportionally to the selection breeding
value (“LIND”); lastly, a simulated annealing technique was applied to maximize gain under explicit constraints on coancestry
(“OPTS”). All three alternative selection scenarios resulted in some relatedness and coancestry among selections, but the
last two provided increases in average breeding values compared to those obtained by the 1/SL scenario. Effective population
sizes (and consequently inbreeding coefficients) varied among the three selection scenarios. Effects of the various selections
on merchantable volume at rotation age were determined using a linear regression model based on an individual tree model (TASS),
which was first run to determine the relationship between merchantable volume and inbreeding (f). LIND and TOP selections yielded the highest breeding values but, due to the increased coancestry among selections, paid
a penalty in the merchantable volume determination. OPTS maximized merchantable volume at rotation age 60 after including
more than 13 selections with an increase of around 3% over that obtained by the 1/SL selection scenario, with an associated
increase in Ne of 50%. Other implications of the three alternative selection scenarios are discussed. 相似文献
110.