Reproduction in a simultaneous hermaphroditic shrimp, Lysmata wurdemanni: any two will do?

The caridean shrimp Lysmata wurdemanni (Gibbes) displays protandric simultaneous hermaphroditism with out-crossing, but not all males become simultaneous hermaphrodites (euhermaphrodites). In this laboratory study, we attempted to determine why some shrimp remain males. In our experiment, we grew L. wurdemanni from postlarvae to adults in several group sizes and observed their reproductive function. We found that all shrimp reared in isolation become euhermaphrodites. When cultured in a group, the proportion of shrimp remaining male decreased with increasing group size. Except for those that mated within a day, inter-molt euhermaphrodite-phase shrimp (with or without embryos) and inter-molt male-phase shrimp fertilized eggs successfully. On the other hand, euhermaphrodite shrimp can only mate as females and have their eggs fertilized during a narrow post-molt window (less than 12 h) in each molt cycle (10 days). The fertilization rate of male-euhermaphrodite pairs was similar to that of euhermaphrodite-euhermaphrodite pairs. There are at least two non-exclusive explanations for the persistence of male shrimp in a group. In certain group compositions, an individual may gain more reproductive fitness as a large male with multiple mating partners than as a small female with low clutch size. Alternatively, the presence of male-phase individuals, with variable molt-cycle duration (5-8 days), may be necessary to ensure mating. This study is the first direct experimental demonstration of social control of sex change in the decapod crustaceans.     

塔里木油田库尔勒生活基地生活垃圾处理现状与对策探讨

对塔里木油田库尔勒生活基地生活垃圾的处理现状和主要构成进行调查后,结合所在城市生活垃圾的处理方式,提出库尔勒生活基地生活垃圾\"分类收集与回收利用\"的途径,分析了实施中可能存在的问题,探讨了具体的对策,强调要从加强环保宣传、明确管理部门责任、完善回收设施、采用半市场化处理的对策思路。     

Environmental decentralization,environmental public service,and public health: evidence from 289 cities in China

Environmental Geochemistry and Health - Effective supply of environmental public services (EPS) is important to guarantee the mitigation of residential pollution exposure risk. This study analyzes...     

中低温NH3-SCR催化剂抗中毒与再生研究进展

中低温氨选择性催化还原（NH₃-SCR）氮氧化物（NO_x）催化剂广泛应用于钢铁、焦化、陶瓷、玻璃、水泥、垃圾焚烧、燃气锅炉等非电行业.不同工况下,硫、酸、碱金属、飞灰等会导致SCR催化剂中毒.因此,如何制备抗中毒性能好的脱硝催化剂,并且有效再生失活SCR催化剂一直是研究热点.本综述针对不同中低温SCR的工况,对比总结脱硝催化剂的应用、抗中毒机制与再生方法,最后对中低温SCR脱硝催化技术进行展望.     

Blood concentrations of lead,cadmium, mercury and their association with biomarkers of DNA oxidative damage in preschool children living in an e-waste recycling area

Reactive oxygen species (ROS)-induced DNA damage occurs in heavy metal exposure, but the simultaneous effect on DNA repair is unknown. We investigated the influence of co-exposure of lead (Pb), cadmium (Cd), and mercury (Hg) on 8-hydroxydeoxyguanosine (8-OHdG) and human repair enzyme 8-oxoguanine DNA glycosylase (hOGG1) mRNA levels in exposed children to evaluate the imbalance of DNA damage and repair. Children within the age range of 3–6 years from a primitive electronic waste (e-waste) recycling town were chosen as participants to represent a heavy metal-exposed population. 8-OHdG in the children’s urine was assessed for heavy metal-induced oxidative effects, and the hOGG1 mRNA level in their blood represented the DNA repair ability of the children. Among the children surveyed, 88.14% (104/118) had a blood Pb level >5 μg/dL, 22.03% (26/118) had a blood Cd level >1 μg/dL, and 62.11% (59/95) had a blood Hg level >10 μg/dL. Having an e-waste workshop near the house was a risk factor contributing to high blood Pb (r _s  = 0.273, p < 0.01), while Cd and Hg exposure could have come from other contaminant sources. Preschool children of fathers who had a college or university education had significantly lower 8-OHdG levels (median 242.76 ng/g creatinine, range 154.62–407.79 ng/g creatinine) than did children of fathers who had less education (p = 0.035). However, we did not observe a significant difference in the mRNA expression levels of hOGG1 between the different variables. Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels (β _Q2 = 0.362, 95% CI 0.111–0.542; β _Q3 = 0.347, 95% CI 0.103–0.531; β _Q4 = 0.314, 95% CI 0.087–0.557). Associations between blood Hg levels and 8-OHdG were less apparent. Compared with low levels of blood Hg (quartile 1), elevated blood Hg levels (quartile 2) were associated with higher 8-OHdG levels (β _Q2 = 0.236, 95% CI 0.039–0.406). Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels.     

对硝基苯酚降解产物与FK506结合蛋白相互作用分子机制

对硝基苯酚（p-nitrophenol,p-NP）作为典型内分泌干扰物,其环境污染与人体健康问题一直是环境领域的研究热点. 环境中对硝基苯酚降解产物（p-NP degradation products,p-NP-DPs）与FK506结合蛋白（FK506 binding protein,FKBP5）结合形成p-NP-DPs-FKBP5加合物是p-NP-DPs产生雌激素和抗雄激素活性的主要机制. 然而,p-NP-DPs与FKBP5相互作用的分子水平机制尚未引起足够的重视. 本文采用分子对接技术模拟计算p-NP-DPs与FKBP5相互作用的结合能和结合面积. 结果表明,p-NP-DPs与FKBP5相互作用结合面积顺序为213 Ų（4-硝基邻苯二酚）>200 Ų（p-NP）>184 Ų（邻苯二酚）>175 Ų（对苯二酚）>173 Ų（苯酚）>171 Ų（对苯醌）,结合能顺序为−3.69 kcal·mol⁻¹（4-硝基邻苯二酚）> −3.76 kcal·mol⁻¹（p-NP）> −3.81 kcal·mol⁻¹（对苯二酚/邻苯二酚）>−3.83 kcal·mol⁻¹（对苯醌）> −3.91 kcal·mol⁻¹（苯酚）,高频氨基酸残基为Pro221、Gly224、Glu227、Ala228、Gly282、Lys283、Tyr284、Met285和Gln286,p-NP-DPs药效团主要包括氢键供体（—OH）、氢键受体（—NO₂和C=O）、芳香中心（苯环）和疏水中心（C原子）. p-NP-DPs理化性质对p-NP-DPs与FKBP5相互作用强度的影响主要取决于分子量和拓扑极表面积（100%）、氢键受体数量（75%）、密度（50%）和闪点（25%）. 本研究对认识水环境中p-NP-DPs分子水平健康效应和环境风险具有重要科学意义.     

CASS工艺脱氮影响因素分析

针对CASS工艺脱氮的效果不够理想、效率不高、出水不够稳定的现象,对脱氮的主要影响因素曝气时间、DO、温度、λ进行了生产性试验研究,分析结果表明,曝气时间3h,D02．5mg／L是本污水厂最合理的参数控制值,曝气时间3h时NH3-N和TN的平均去除率分别为89．7％和59．7％,D02．5mg／L时NH3-N和TN的平均去除率分别为94．5％和71．3％,脱氮效果良好;温度对脱氮的效果有很明显的影响,春季的脱氮效果明显好于冬季;脱氮效果随冲水比的增高而降低,但出水均达标说明CASS工艺有良好的抗冲击负荷的能力。     

鲢鱼、草鱼和尼罗罗非鱼热休克蛋白70基因cDNA全序列的克隆与分析

采用RT-PCR技术和RACE技术分别从淡水食毒藻鱼类鲢鱼(Hypophthalmichthys molitrix)、尼罗罗非鱼(Oreochromis nilotica)及草食性鱼类草鱼(Ctenopharyngodon idella)肝脏扩增出热休克蛋白70(HSP70)cDNA全序列,并与其它鱼类、两栖类和哺乳类动物的HSP70氨基酸进行了同源性比较.结果表明,鲢鱼、草鱼和尼罗罗非鱼肝脏HSP70基因cDNA全长分别为2356bp、2348bp和2242bp,分别编码649、649和638个氨基酸.鲢鱼、草鱼和尼罗罗非鱼HSP70与其它鱼类、两栖类和哺乳类动物HSP70氨基酸同源性均较高,表明其在进化上高度保守,且承担着重要的生理功能.构建系统进化树发现,鲢鱼、草鱼与其它鲤科鱼类斑马鱼、银鲫(Carassius auratus gibelio)的HSP70氨基酸同源性较高,处于同一进化树分枝;而尼罗罗非鱼HSP70未与其它鲈形目鱼类,如鲷科鱼类聚为一枝,而是占据一个独立的分枝,这与克隆得到的鲢鱼、草鱼肝脏HSP70基因可能为结构型HSP70,而尼罗罗非鱼肝脏HSP70基因可能为诱导型HSP70的结果相一致.     

How does anti-corruption affect enterprise green innovation in China’s energy-intensive industries?

Environmental Geochemistry and Health - Rampant corruption exists in China’s energy-intensive industries. However, we know little about the nexus of corruption and enterprise green innovation...