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.     

天津市自然保护地与区域生境质量的时空演变格局

生境质量是反映区域生物多样性水平的重要指标,而规划科学、管理有效的自然保护地对于维护生境质量、巩固区域生态安全具有重要作用。以天津市为例,运用InVEST模型Habitat Quality模块评估了天津市2000、2005、2010、2015、2018年生境质量时空变化格局,基于叠加分析自然保护地内外生境质量变化探讨自然保护地对维护区域生境质量发挥的作用。结果表明：(1)2000—2018年间天津市生境质量总体下降了13.18%,并呈现出明显的由中心城区向环城四区扩散的趋势,高质量区域仅占天津陆域国土面积的4%,主要分布在天津北部山区和于桥水库、团泊洼、北大港、大黄堡等湿地。(2)天津保护地空间分布上呈集中分布态势,覆盖了天津市约75%的高质量生境区域和25%的较高质量生境区域。(3)从整体上看不同类型的自然保护地内生境质量保护效果不同,自然保护区优于其它类保护地,其生境质量明显得到提升。所有保护地中有10处保护地生境质量略有下降,但低于全域下降水平,只有盘山风景名胜区和古海岸与湿地自然保护区生境质量下降高于全域平均水平。(4)自然保护地对天津市生境质量下降的趋势起到了一定缓冲作用,其...     

Mercury transport and fate in municipal solid waste landfills and its implications

Mercury (Hg) release and migration from municipal solid waste landfills has been an important issue to nearby ecosystems and human health. To completely understand the Hg biogeochemical cycle in landfills, this review presents the Hg emission processes via different pathways, related controlling mechanisms, and critical Hg transport and transformation processes involving the diffusion and advection of Hg, Hg volatilization, Hg adsorption and desorption, Hg redox reactions, and Hg methylation and demethylation. These critical physical, chemical, and biological processes result in the phase transfer of Hg and the distribution of different Hg species in landfill gas (LFG), leachates, and cover soils. In addition, key factors (e.g., LFG, meteorological conditions, cover soils, and vegetation) affecting Hg emission processes and their impacts are discussed here. This work provides a comprehensive picture of Hg behavior in landfills, and has positive implications for the development of a process-based model and the control of Hg emissions from landfills.

     

Structural basis for role of ring finger protein RNF168 RING domain

Ubiquitin adducts surrounding DNA double-strand breaks (DSBs) have emerged as molecular platforms important for the assembly of DNA damage mediator and repair proteins. Central to these chromatin modifications lies the E2 UBC13, which has been implicated in a bipartite role in priming and amplifying lys63-linked ubiquitin chains on histone molecules through coupling with the E3 RNF8 and RNF168. However, unlike the RNF8-UBC13 holoenyzme, exactly how RNF168 work in concert with UBC13 remains obscure. To provide a structural perspective for the RNF168-UBC13 complex, we solved the crystal structure of the RNF168 RING domain. Interestingly, while the RNF168 RING adopts a typical RING finger fold with two zinc ions coordinated by several conserved cystine and histine residues arranged in a C3HC4 “cross-brace” manner, structural superimposition of RNF168 RING with other UBC13-binding E3 ubiquitin ligases revealed substantial differences at its corresponding UBC13-binding interface. Consistently, and in stark contrast to that between RNF8 and UBC13, RNF168 did not stably associate with UBC13 in vitro or in vivo. Moreover, domain-swapping experiments indicated that the RNF8 and RNF168 RING domains are not functionally interchangeable. We propose that RNF8 and RNF168 operate in different modes with their cognate E2 UBC13 at DSBs.     

Changes in Ataxin-10 Expression after Sciatic Nerve Crush in Adult Rats

Ataxin-10 is a cytoplasmic protein that belongs to the family of armadillo repeat proteins and the ataxin proteins are ubiquitously expressed in nervous tissue. A loss of Ataxin-10 in primary neuronal cells causes increased apoptosis of cerebellar neurons. Knockdown of ATXN10 with siRNA in HeLa cells results in cytokinesis defects-multinucleation. Because of the essential role of Ataxin-10 in nervous system and cellular cytokinesis, we investigated the spatiotemporal expression of Ataxin-10 in a rat sciatic nerve crush (SNC) model. After never injury, we observed that Ataxin-10 had a significant up-regulation from 3d, peaked at day 5 and then gradually decreased to the normal level at 4 weeks. At its peak expression, Ataxin-10 expressed mainly in Schwann cells and macrophages of the distal sciatic nerve segment from injury, but had few co-localizations in axons. Besides, the peak expression of Ataxin-10 was in parallel with proliferating cell nuclear antigen (PCNA), and Ataxin-10 co-labeled with PCNA. Thus, all of our findings suggested that Ataxin-10 may be involved in the pathophysiology of sciatic nerve after SNC.     

Prevalence of Metabolic Syndrome and Its Components among Chinese Professional Athletes of Strength Sports with Different Body Weight Categories

Background

There is an increasing concern on cardiometabolic health in young professional athletes at heavy-weight class.

Objective

Our cross-sectional survey aimed to evaluate the prevalence of metabolic syndrome and clustering of metabolic risk factors in a population of young and active professional athletes of strength sports in China.

Methods

From July 2006 to December 2008, a total of 131 male and 130 female athletes of strength sports were enrolled. We used two criteria provided by the Chinese Diabetes Society (2004) and the National Cholesterol Education Program''s Adult Treatment Panel III (2002) to define the metabolic syndrome and its individual components, respectively.

Results

Regardless of their similar ages (mean: 21 years) and exercise levels, athletes in the heaviest-weight-class with unlimited maximum body weight (UBW) boundaries (mean weight and BMI: 130 kg and 38 kg/m² for men, 110 kg and 37 kg/m² for women) had significantly higher prevalence of metabolic syndrome than did those in all other body-weight-class with limited body weight (LBW) boundaries (mean weight and BMI: 105 kg and 32 kg/m² for men, 70 kg and 26 kg/m² for women). Prevalence of metabolic syndrome using CDS criteria (UBW vs. LBW: 89% vs. 18% for men, 47% vs. 0% for women) and its individual components, including central obesity, hypertension, hypertriglyceridemia, low high-density lipoprotein-cholesterol levels, and impaired fasting glucose, were all significantly higher in athletes at the heaviest weight group with UBW than all other weight groups with LBW.

Conclusions

Our study suggests that professional athletes of strength sports at the heaviest-weight-class are at a significant increased risk of cardiometabolic disease compared with those at all other weight categories. The findings support the importance of developing and implementing the strategy of early screening, awareness, and interventions for weight-related health among young athletes.