The effect of the red wine polyphenol resveratrol on a rat model of biliary obstructed cholestasis: involvement of anti-apoptotic signalling, mitochondrial biogenesis and the induction of autophagy

Mitochondria are known to be involved in cholestatic liver injury. The potential protective effect of resveratrol in cholestatic liver injury and the possible roles of autophagy and apoptosis induction in this process are not yet clear. The aim of this study is to determine whether resveratrol administration after bile duct ligation can reduce cholestasis-induced liver injury through modulating apoptosis, mitochondrial biogenesis and autophagy. A rat model of cholestasis was established by bile duct ligation (BDL) and compared with a sham group receiving laparotomy without BDL, with resveratrol or control treatments following BDL. The expression of proteins involved in the apoptotic and autophagic pathways were analyzed by western blotting. Apoptosis was examined by TUNEL staining. In the resveratrol/BDL group LC3-II upregulation persisted for 1-7 days, Bax was downregulated and catalase was upregulated at 3-7 days after resveratrol treatment. The decline in mitochondrial DNA copy number was reversed at 3-7 days. Caspase 3 expression was significantly downregulated at 3-7 days in the resveratrol group. TUNEL staining showed significant numbers of apoptotic liver cells appeared in livers 3-7 days after BDL and that was decreased by resveratrol treatment. Our results indicate that early resveratrol treatment reverses impaired liver function within hours of BDL.     

松材线虫及其关键传媒墨天牛的研究进展

松材线虫Bursaphelenchusxylophilus (Steiner&Buhere,1 93 4Nickle,1 981 )是一种世界多国公认的重大外来生物。其原产地在美国 ,但松材线虫并不严重危害该国松林 ;日本受害最重 ,经过几十年的研究与防治 ,现已基本能控制松材线虫病大发生。自 1 982年我国南京中山陵首次发现松材线虫以来 ,其在我国的扩散趋势越来越明显 ,现已成为我国一种重要入侵病原生物。它不但对我国南方数百万公顷松林构成毁灭性威胁 ,影响我国经济和社会可持续发展 ,而且将破坏我国一些著名风景名胜区、文化遗产地。同时 ,松材线虫正成为一项技术壁垒 ,严重影响我国的进出口贸易。该文简要从松材线虫及其关键传煤墨天牛Monochamusspp .的生物学特性、分布状况 ,松材线虫病的蔓延条件及影响因素等方面概述国内外的研究动态 ,以期为我国对松材线虫的研究与防治工作提供参考     

Potential risk of biologic pollution associated to the introduction of <i>Pinus radiata</i> in grassland areas

Afforestation is a recommended practice to mitigate global warming. However, their implementation may generate undesirable impacts, mostly if exotic species are used. Plantations of Pinus radiata D Don in Ventania (Bs. As., Argentina) soils showed notorious increments of extractable P (Pe), which could affect the dynamic of this element as well as the degree of phosphorus saturation (GSP_Bray). The objectives of this study were: i) to quantify the GSP_Bray in Mollisols afforested with P. radiata comparing the results with those coming from adjacent, natural grassland areas (base line); ii) to evaluate the potential environmental risk induced by afforestation through the identification of a change point (PC) in the GSP_Bray indicative of a phosphate leaching increment. Treatments included mature stands of P. radiata (TB) and adjacent areas with natural grassland vegetation (TP). Samples were taken at 0-15; 15-30 and 30-45 cm soil depth, and texture, pH, total organic carbon (COT), Pe, soluble reactive phosphorus (PSR), phosphorus sorption index (ISP) and GSP_Bray were determined. The results showed a significant acidification in TB and an increase in the COT stock, indicating an additional atmospheric CO₂ sequestration by the trees. The Pe and PSR values were notoriously higher in TB, and they were reflected in a significant increment in the GSP_Bray with respect to TP. The detection of a significant PC in the GSP_Bray-PSR regression indicates higher chances of phosphate leaching in the forest stands, which could reach water courses, lakes and artificial reservoirs promoting their eutrophication. Because of the potential environmental pollution risk of biologic origin derived from the afforestation with P. radiata in Mollisols areas, their inclusion in clean development practices must be reconsidered.     

Populations Microbiennes Des Bois

Resumé Les auteurs ont étudié la composition chimique (N, substances humiques, lignine) de copeaux de bois blanc exposés à l'air libre depuis 2 à 10 ans, ainsi que leur type de peuplement fongique. En l'absence de lignivore, le pH, les taux de lignine et d'N s'élèvent et il se forme des quantités modérées d'humus à forte capacité d'échange. Dans le cas contraire, on voit apparaître, en abondance, des substances humiques peu condensées et la matière organique subit une évolution rappelant celle du mor.Avec la collaboration technique de Melle. M. Clet.Kononova, dans sa monographie⁵, signale de Troussov (1916) une étude que nous n'avons pas eu en mains.     

Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.      

An image-based RNAi screen identifies SH3BP1 as a key effector of Semaphorin 3E–PlexinD1 signaling

Extracellular signals have to be precisely interpreted intracellularly and translated into diverse cellular behaviors often mediated by cytoskeletal changes. Semaphorins are one of the largest families of guidance cues and play a critical role in many systems. However, how different cell types translate extracellular semaphorin binding into intracellular signaling remains unclear. Here we developed and performed a novel image-based genome-wide functional RNAi screen for downstream signaling molecules that convert the interaction between Semaphorin 3E (Sema3E) and PlexinD1 into cellular behaviors. One of the genes identified in this screen is a RhoGAP protein, SH3-domain binding protein 1 (SH3BP1). We demonstrate that SH3BP1 mediates Sema3E-induced cell collapse through interaction with PlexinD1 and regulation of Ras-related C3 botulinum toxin substrate 1 (Rac1) activity. The identification and characterization of SH3BP1 as a novel downstream effector of Sema3E-PlexinD1 provides an explanation for how extracellular signals are translated into cytoskeletal changes and unique cell behavior, but also lays the foundation for characterizing other genes identified from our screen to obtain a more complete picture of plexin signaling.     

MicroRNA-29a protects against acute liver injury in a mouse model of obstructive jaundice via inhibition of the extrinsic apoptosis pathway

Recent studies have shown that microRNA-29 (miR-29) is significantly decreased in liver fibrosis, as demonstrated in human liver cirrhosis, and that its downregulation influences the activation of hepatic stellate cells. In addition, both cleaved caspase-3 production and apoptosis play a role in cholestatic liver injury. However, it is unknown if miR-29 is effective in modulating the extent of injury. We employed miR-29a transgenic mice (miR-29aTg mice) and wild-type (WT) littermates to clarify the role of miR-29 in hepatic injury and fibrogenesis, using the bile duct-ligation (BDL) mouse model. After BDL, all three members of the miR-29 family were significantly downregulated in the livers of WT mice, and miR-29b and miR-29c were significantly downregulated in the livers of the miR-29aTg mice. Liver function, as measured by alanine transaminase and aspartate transaminase activity, was significantly improved in the miR-29aTg mice than in the WT littermates, following 1 week of obstructive jaundice. In addition, overexpression of miR-29a was associated with a significant downregulation of the expression of collagen-1α1, collagen-4α1, phospho-FADD, cleaved caspase-8, cleaved caspase-3, Bax, Bcl-2, PARP, and nuclear factor-κB, as well as an upregulation of phospho-AKT expression. In addition, there were significantly fewer TUNEL-positive liver cells in the miR-29aTg group than in the WT littermates after BDL. Our results indicate that miR-29a decreases cholestatic liver injury and fibrosis after BDL, at least partially, by modulating the extrinsic rather than intrinsic pathway of apoptosis.