Expression of SGTA correlates with neuronal apoptosis and reactive gliosis after spinal cord injury

Small glutamine-rich tetratricopeptide repeat (TPR)-containing protein alpha (SGTA) is a novel TPR-containing protein involved in various biological processes. However, the expression and roles of SGTA in the central nervous system remain unknown. We have produced an acute spinal cord injury (SCI) model in adult rats and found that SGTA protein levels first significantly increase, reach a peak at day 3 and then gradually return to normal level at day 14 after SCI. These changes are striking in neurons, astrocytes and microglia. Additionally, colocalization of SGTA/active caspase-3 has been detected in neurons and colocalization of SGTA/proliferating cell nuclear antigen has been detected in astrocytes and microglial. In vitro, SGTA depletion by short interfering RNA inhibits astrocyte proliferation and decreases cyclinA and cyclinD1 protein levels. SGTA knockdown also reduces neuronal apoptosis. We speculate that SGTA is involved in biochemical and physiological responses after SCI.     

Effect of photoperiod on growth and gonadal development of juvenile Topmouth Gudgeon Pseudorasbora parva

In this study, we investigated the effect of photoperiod on growth and gonadal development of juvenile topmouth gudgeon, Pseudorasbora parva. Seven different photoperiods (light:dark, L:D) were tested: 0L:24D, 4L:20D, 8L:16D, 12L:12D, 16L:8D, 20L:4D and 24L:0D, from November to January. Throughout the study, light intensity was kept at 400 lx on the water surface, and the fish were fed a commercial diet twice a day. Weight gain, feed intake, specific growth rate, and feed conversion efficiency were significantly higher under the constant–long day photoperiods (24L:0D, 20L:4D and 16L:8D) than those under the short–no day photoperiods (12L:12D, 8L:16D, 4L:20D, 0L:24D) (p?<?0.05). The highest mean female gonadosomatic index (GSI) and mean oocyte size were observed under 24L:0D followed by 20L:4D and 16L:8D photoperiods, and these parameters were significantly higher than those of fish cultured under the short–no day photoperiod regimes (p?<?0.05). Proportion of females with GSI?>?9 % were 50.00 %, 46.67 %, 48.48 %, in 24L:0D, 20L:4D and 16L:8D, respectively. These results demonstrate that the growth of juvenile P. parva can be stimulated significantly by constant–long photoperiods and that these photoperiods can advance sexual maturity of females by approximately 2 months.     

珠三角河网水域栅藻的时空分布特征

珠三角河网水域是珠江之水流入南海的必经之地,对2012年该水域浮游植物群落中的栅藻种类丰富度和生物量的时空特征及其环境影响因子进行系统阐析。调查期间共发现栅藻24种(包括变种、变型),其中具刺和无刺种类分别为11种和13种。出现率高且生物量贡献率大的物种仅3种,包括被甲栅藻原变种(Scenedesmus armatus var.armatus)、被甲栅藻博格变种双尾变型(S.armatus var.boglariensis f.bicaudatus)和二形栅藻(S.dimorphus),分析认为这3个物种在栅藻种群中的生态优势很可能与其形态特征存在一定的关联。栅藻种类丰富度的季节分布呈现丰水期高于枯水期的特征,空间分布呈现河网中部站位低于外侧站位的特征。此外,种类丰富度的空间分布格局存在季节差异,丰水季节呈现河网中部站位明显低于外侧站位的特征,而枯水季节西江沿线站位种类丰富度明显偏低。分析认为,水温和径流是影响栅藻种类丰富度季节变动的关键因素;同时,径流也是影响总种类丰富度空间分布格局的关键因素,而水温和营养盐是影响不同季节种类丰富度的空间格局的重要因素。栅藻种群生物量的季节分布呈现丰水期高于枯水期的特征,空间分布表现为珠江桥站位的生物量明显高于其它站位。分析认为,径流和水温是决定种群生物量季节变动的关键因素,而营养盐、水体稳定性和盐度是决定生物量空间分布格局的关键因素。栅藻生物量与种类丰富度的关系基本符合单峰模型,且偏重于单峰模型的上升区,丰富了全球多样性模式的分级特征和区域特征。     

Streptosporangium shengliensis sp. nov., a novel actinomycete isolated from a lake sediment

A novel actinomycete, designated strain NEAU-GH7^T, was isolated from a lake sediment and characterized using a polyphasic approach. Strain NEAU-GH7^T was Gram-stain positive, aerobic, non-spore-forming and produced spherical sporangia. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain NEAU-GH7^T formed a monophyletic clade with the closest relative Streptosporangium longisporum DSM 43180^T (99.0 %), an association that was supported by a bootstrap value of 74 % in the neighbour-joining tree and also recovered with the maximum-likelihood algorithm. However, the low level of DNA–DNA relatedness allowed the strain to be differentiated from its closest relative. Moreover, strain NEAU-GH7^T could also be differentiated from S. longisporum DSM 43180^T and other Streptosporangium species showing high 16S rRNA gene sequence similarity (>98.0 %) by morphological and physiological characteristics. On the basis of phylogenetic analysis, DNA–DNA hybridization and phenotypic characteristics, strain NEAU-GH7^T should be classified as a new species of the genus Streptosporangium, for which the name Streptosporangium shengliensis sp. nov. is proposed. The type strain is NEAU-GH7^T (=CGMCC 4.7105^T=DSM 45881^T).     

Genome evolution in Oryza allopolyploids of various ages: Insights into the process of diploidization

The prevalence and recurrence of whole-genome duplication in plants and its major role in evolution have been well recognized. Despite great efforts, many aspects of genome evolution, particularly the temporal progression of genomic responses to allopolyploidy and the underlying mechanisms, remain poorly understood. The rice genus Oryza consists of both recently formed and older allopolyploid species, representing an attractive system for studying the genome evolution after allopolyploidy. In this study, through screening BAC libraries and sequencing and annotating the targeted BAC clones, we generated orthologous genomic sequences surrounding the DEP1 locus, a major grain yield QTL in cultivated rice, from four Oryza polyploids of various ages and their likely diploid genome donors or close relatives. Based on sequenced DEP1 region and published data from three other genomic regions, we investigated the temporal evolutionary dynamics of four polyploid genomes at both genetic and expression levels. In the recently formed BBCC polyploid, Oryza minuta, genome dominance was not observed and its short-term responses to allopolyploidy are mainly manifested as a high proportion of homoeologous gene pairs showing unequal expression. This could partly be explained by parental legacy, rewiring of divergent regulatory networks and epigenetic modulation. Moreover, we detected an ongoing diploidization process in this genus, and suggest that the expression divergence driven by changes of selective constraint probably plays a big role in the long-term diploidization. These findings add novel insights into our understanding of genome evolution after allopolyploidy, and could facilitate crop improvements through hybridization and polyploidization.     

黄土典型坝系流域碳沉积特征及其源解析

沉积物信息能够反映流域侵蚀环境变化,研究沉积物碳赋存规律对流域侵蚀过程和生态恢复具有重要指示意义。本文选取黄土高原典型坝系流域,通过土壤沉积剖面取样和室内测试分析,同时利用稳定同位素技术,分析了坝地及沟道沉积土壤剖面的碳分布特征及其来源解析。结果显示：（1）淤地坝沉积土壤总碳含量和土壤有机碳含量变化范围分别为12.80-14.76 g/kg和1.34-3.53 g/kg;沟道沉积土壤总碳含量和土壤有机碳含量变化范围分别为13.61-17.86 g/kg和1.52-5.04 g/kg。（2）淤地坝土壤总碳含量在土壤深度0-100 cm和350-500 cm区间波动较为平缓,100-350 cm波动较大;沟道0-200 cm土壤层总碳含量沉积变化较大,而200-390 cm土壤层变化平缓。淤地坝和沟道沉积土壤有机碳含量随土壤深度增加呈现降低趋势。（3）淤地坝有机碳同位素变化范围为-23.96‰——22.09‰,整体上呈现表层土偏正,并随土壤深度增加而呈现偏负的趋势;沟道沉积土壤有机碳同位素变化范围为-27.04‰——24.58‰,随土壤随深度增加呈现偏正的趋势。（4）羊圈沟坝地表层土壤有机碳多来源于灌木（占96.80%）,沟道表层土壤有机碳则多来自于灌木和草地（分别占62.05%、32.4%）。     

Bone marrow mesenchymal stem cells-derived exosomes reduce Aβ deposition and improve cognitive function recovery in mice with Alzheimer's disease by activating sphingosine kinase/sphingosine-1-phosphate signaling pathway

Exosomes are associated with the development and progression of Alzheimer's disease (AD), although the impact of these extracellular vesicles in brain pathological condition remains incompletely understood. Therefore, this study aimed to investigate the role and mechanism of exosomes signaling in AD. Double transgenic APP/PS1 mice were injected with bone marrow mesenchymal stem cells (BM-MSCs)-derived exosomes or combined with SKI-Ⅱ (sphingosine kinase [SphK] inhibitor) or VPC23019 (sphingosine-1-phosphate [S1P] 1 receptor blocker). We observed the spatial learning and memory ability of mice, and assessed the levels of amyloid and proteins. We found that exosomes improved spatial learning and memory ability of APP/PS1 mice, and enhanced the expression of SphK1 and S1P1. Moreover, exosomes inhibited the levels of amyloid and enhanced the expression of NeuN in cortex and hippocampus of APP/PS1 mice. Exosomes repressed the levels of Aβ1-40, Aβ1-42, BACE1, and PS1, and promoted the expression of neprilysin in APP/PS1 mice. The influence conferred by exosomes was abolished by SKI-Ⅱ or VPC23019. In conclusion, our article confirms that BM-MSCs-derived exosomes reduce Aβ deposition and promote cognitive function recovery in AD mice by activating SphK/S1P signaling pathway. Thus, our data suggest that S1P/SphK-containing exosomes should be explored as potential AD cure.