CD82 protects against glaucomatous axonal transport deficits via mTORC1 activation in mice

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive optic nerve degeneration and retinal ganglion cell loss. Axonal transport deficits have been demonstrated to be the earliest crucial pathophysiological changes underlying axonal degeneration in glaucoma. Here, we explored the role of the tetraspanin superfamily member CD82 in an acute ocular hypertension model. We found a transient downregulation of CD82 after acute IOP elevation, with parallel emergence of axonal transport deficits. The overexpression of CD82 with an AAV2/9 vector in the mouse retina improved optic nerve axonal transport and ameliorated subsequent axon degeneration. Moreover, the CD82 overexpression stimulated optic nerve regeneration and restored vision in a mouse optic nerve crush model. CD82 exerted a protective effect through the upregulation of TRAF2, which is an E3 ubiquitin ligase, and activated mTORC1 through K63-linked ubiquitylation and intracellular repositioning of Raptor. Therefore, our study offers deeper insight into the tetraspanin superfamily and demonstrates a potential neuroprotective strategy in glaucoma treatment.Subject terms: Molecular neuroscience, Neurodegeneration     

The complete chloroplast genome sequence and phylogenetic analysis of <Emphasis Type="Italic">Chuanminshen</Emphasis> (<Emphasis Type="Italic">Chuanminshenviolaceum</Emphasis> Sheh et Shan)

Chloroplast genome sequences are very useful for species identification and phylogenetics. Chuanminshen (Chuanminshen violaceum Sheh et Shan) is an important traditional Chinese medicinal plant, for which the phylogenetic position is still controversial. In this study, the complete chloroplast genome of Chuanminshen violaceum Sheh et Shan was determined. The total size of Chuanminshen chloroplast genome was 154,529 bp with 37.8% GC content. It has the typical quadripartite structure, a large single copy (17,800 bp) and a small single copy (84,171 bp) and a pair of inverted repeats (26,279 bp). The whole genome harbors 132 genes, which includes 85 protein coding genes, 37 tRNA genes, eight rRNA genes, and two pseudogenes. Thirty-nine SSR loci, 32 tandem repeats and 49 dispersed repeats were found. Phylogenetic analyses results with the help of MEGA showed a new insight for the Chuanminshen phylogenetic relationship with the reported chloroplast genomes in Apiales plants.     

Soil carbon dynamics in a Pinus massoniana plantation following clear-cutting and slash removal

Aims Slash removal is a common practice to prepare recently harvested sites for replanting. However, little is known about its impact on soil carbon (C) dynamics in subtropical plantations. This study evaluates the effects of burning versus manual slash removal site preparation treatments on soil organic carbon (SOC), soil respiration and soil microbial community structure in a Pinus massoniana plantation in southern China.Methods Three areas within a mature P. massoniana plantation were clearcut. Two months following harvesting, slash on one-half of each area was burned (BURN), whereas slash was manually removed (MANR) on the other portion. Slash removal treatments were also compared with adjacent uncut plantation areas (UNCUT). Soil samples, and soil respiration measurements were used to characterize soil properties and microbial communities following slash removal treatments. Important findings Mean soil respiration rates from the MANR and BURN treatments were 26% and 17% lower, respectively, than the UNCUT treatment over 1 year. The MANR and BURN treatment resulted in soils with 27% and 9% reduction in total phospholipid fatty acids (PLFAs) and 18% and 10% reduction in bacterial PLFAs, respectively, compared with the UNCUT treatment. However, no significant differences existed between slash removal treatments with respect to soil chemical properties, SOC chemical compositions, soil respiration and microbial communities; although PLFA patterns were notably different for the burned plots. Most factors affecting C dynamics and microbial communities were not sensitive to the differences imparted to the ecosystem due to manual slash removal or burning. Our results suggested that low-intensity burning after clear-cutting might have no significant effect on soil C pool and its dynamics compared with manual slash removal in subtropical plantations.     

吉林珲春自然保护区东北虎和东北豹及其有蹄类猎物的多度与分布

珲春国家级自然保护区是东北虎(Panthera tigris altaica)、东北豹(Panthera pardus orientalis)等濒危物种在中国的核心分布区。为了探究该区域野生动物的多度水平和空间分布, 了解人类干扰情况, 我们运用相对多度指数(relative abundance index, RAI)分析了2013年4-6月设置于此的83个红外相机位点的监测数据。红外相机的总捕获天数6,060 d, 共捕获10科18种野生哺乳动物, 其中鼬科4种, 猫科动物3种, 犬科、鹿科和松鼠科各2种, 猪科、熊科、麝科、猬科和兔科各1种。研究期间共拍摄到东北虎11只个体, 东北豹13只个体。从相对多度指数来看, 东北虎的相对多度(0.84)远高于东北豹(0.48), 它们的有蹄类猎物中梅花鹿(Cervus nippon)的相对多度最高(2.18), 其次为狍(Capreolus pygargus)(1.53)和野猪(Sus scrofa)(0.92)。人类活动和放牧的相对多度水平(分别为40.64和2.76)显著高于野生动物。在空间分布上, 东北虎和梅花鹿主要在保护区的核心区分布, 且与保护区社区共管区的多度水平差异显著, 而东北豹在不同功能区之间的分布差异不显著, 狍在保护区北部的多度水平较高, 但各功能区之间差异不显著, 野猪在社区共管区的多度水平显著高于核心区。可见, 核心区频繁的人类活动和放牧活动对野生动物的保护产生了影响, 未来应加强关于人类干扰对虎、豹种群及其有蹄类猎物的影响评估。     

Deficiency in a cytosolic ribose-5-phosphate isomerase causes chloroplast dysfunction, late flowering and premature cell death in Arabidopsis

The oxidative pentose phosphate pathway (oxPPP) is part of central metabolism, consisting of two distinct phases: the oxidative phase and the non-oxidative phase. The non-oxidative phase of the oxPPP generates carbon skeletons for the synthesis of nucleotides, aromatic amino acids, phenylpropanoids and their derivatives, which are essential for plant growth and development. However, it is not well understood how the non-oxidative phase of the oxPPP contributes to plant growth and development. Here, we report the characterization of Arabidopsis T-DNA knockout mutants of the RPI2 gene (At2g01290), which encodes a cytosolic ribose-5-phosphate isomerase (RPI) that catalyzes the reversible interconversion of ribulose-5-phosphate and ribose-5-phosphate in the non-oxidative phase of the oxPPP. Although recombinant Arabidopsis RPI2 protein exhibits marked RPI enzymatic activity, knockout of the RPI2 gene does not significantly change the total RPI activity in the mutant plants. Interestingly, knockout of RPI2 interferes with chloroplast structure and decreases chloroplast photosynthetic capacity. The rpi2 mutants accumulate less starch in the leaves and flower significantly later than wild-type when grown under short-day conditions. Furthermore, the rpi2 mutants display premature cell death in the leaves when grown at an above-normal temperature (26°C). These results demonstrate that a deficiency in the non-oxidative phase of the cytosolic oxPPP has pleiotropic effects on plant growth and development and causes premature cell death.     

酿酒酵母菌核糖体RNA沉降系数的初步研究

为研究酿酒酵母菌核糖体RNA(rRNA)的沉降系数,用酶解法和液氮研磨法裂解酿酒酵母菌的细胞壁,Trizol Reagent提取其总RNA,同时提取小白鼠和斑马鱼的总RNA进行比较.经紫外分光光度计检测和甲醛琼脂糖变性胶电泳后,RNA纯度好,条带清晰,无弥散或降解现象.试验发现,与酶解法相比,用液氮研磨法破碎酿酒酵母菌细胞壁提取总RNA所用的成本低,时间少,产率和纯度高,适用于少量样品RNA的提取.同时,酿酒酵母菌与斑马鱼和小白鼠总RNA电泳图谱表明,三者的"18S rRNA"在条带大小方面差异较小,而"28S rRNA"差异较大.利用分析型离心机测得的酿酒酵母菌两个较大rRNA的沉降系数分别为24.7S和18.1S.研究结果表明了真核生物rRNA种类的多样性.     

Ultrasound stimulates NF‐κB activation and iNOS expression via the Ras/Raf/MEK/ERK signaling pathway in cultured preosteoblasts

It has been shown that ultrasound (US) stimulation accelerates fracture healing in the animal models and non‐operatively clinical uses. Nitric oxide (NO) is a crucial early mediator in mechanically induced bone formation. Here we found that US‐mediated inducible nitric oxide synthase (iNOS) expression was attenuated by Ras inhibitor (manumycin A), Raf‐1 inhibitor (GW5074), MEK inhibitor (PD98059), NF‐κB inhibitor (PDTC), and IκB protease inhibitor (TPCK). US‐induced Ras activation was inhibited by manumycin A. Raf‐1 phosphorylation at Ser³³⁸ by US was inhibited by manumycin A and GW5074. US‐induced MEK and ERK activation was inhibited by manumycin A, GW5074, and PD98059. Stimulation of preosteoblasts with US activated IκB kinase α/β (IKK α/β), IκBαphosphorylation, p65 phosphorylation at Ser²⁷⁶, p65, and p50 translocation from the cytosol to the nucleus, and κB‐luciferase activity. US‐mediated an increase of IKK α/β, IκBα, and p65 phosphorylation, κB‐luciferase activity and p65 and p50 binding to the NF‐κB element was inhibited by manumycin A, GW5074, and PD98059. Our results suggest that US increased iNOS expression in preosteoblasts via the Ras/Raf‐1/MEK/ERK/IKKαβ and NF‐κB signaling pathways. J. Cell. Physiol. 220: 196–203, 2009. © 2009 Wiley‐Liss, Inc.     

Transporter genes expressed by coastal bacterioplankton in response to dissolved organic carbon

Coastal ocean bacterioplankton control the flow of dissolved organic carbon (DOC) from terrestrial and oceanic sources into the marine food web, and regulate the release of inorganic carbon to atmospheric and offshore reservoirs. While the fate of the chemically complex coastal DOC reservoir has long been recognized as a critical feature of the global carbon budget, it has been problematic to identify both the compounds that serve as major conduits for carbon flux and the roles of individual bacterioplankton taxa in mediating that flux. Here we analyse random libraries of expressed genes from a coastal bacterial community to identify sequences representing DOC‐transporting proteins. Predicted substrates of expressed transporter genes indicated that carboxylic acids, compatible solutes, polyamines and lipids may be key components of the biologically labile DOC pool in coastal waters, in addition to canonical bacterial substrates such as amino acids, oligopeptides and carbohydrates. Half of the expressed DOC transporter sequences in this coastal ocean appeared to originate from just eight taxa: Roseobacter, SAR11, Flavobacteriales and five orders of γ‐Proteobacteria. While all major taxa expressed transporter genes for some DOC components (e.g. amino acids), there were indications of specialization within the bacterioplankton community for others (e.g. carbohydrates, carboxylic acids and polyamines). Experimental manipulations of the natural DOC pool that increased the concentration of phytoplankton‐ or vascular plant‐derived compounds invoked a readily measured response in bacterial transporter gene expression. This highly resolved view of the potential for carbon flux into heterotrophic bacterioplankton cells identifies possible bioreactive components of the coastal DOC pool and highlights differing ecological roles in carbon turnover for the resident bacterial taxa.