Declined miR‐181a‐5p expression is associated with impaired natural killer cell development and function with aging

MicroRNAs (miRNAs) regulate gene expression and thereby influence cell development and function. Numerous studies have shown the significant roles of miRNAs in regulating immune cells including natural killer (NK) cells. However, little is known about the role of miRNAs in NK cells with aging. We previously demonstrated that the aged C57BL/6 mice have significantly decreased proportion of mature (CD27⁻CD11b⁺) NK cells compared with young mice, indicating impaired maturation of NK cells with aging. Here, we performed deep sequencing of CD27⁺ NK cells from young and aged mice. Profiling of the miRNome (global miRNA expression levels) revealed that 49 miRNAs displayed a twofold or greater difference in expression between young and aged NK cells. Among these, 30 miRNAs were upregulated and 19 miRNAs were downregulated in the aged NK cells. We found that the expression level of miR‐l8la‐5p was increased with the maturation of NK cells, and significantly decreased in NK cells from the aged mice. Knockdown of miR‐181a‐5p inhibited NK cell development in vitro and in vivo. Furthermore, miR‐181a‐5p is highly conserved in mice and human. MiR‐181a‐5p promoted the production of IFN‐γ and cytotoxicity in stimulated NK cells from both mice and human. Importantly, miR‐181a‐5p level markedly decreased in NK cells from PBMC of elderly people. Thus, our results demonstrated that the miRNAs profiles in NK cells change with aging, the decreased level of miR‐181a‐5p contributes to the defective NK cell development and function with aging. This opens new strategies to preserve or restore NK cell function in the elderly.     

Survivorship of geographic Pomacea canaliculata populations in responses to cold acclimation

1. Pomacea canaliculata, a freshwater snail from South America, has rapidly established natural populations from south to north subtropical region in China, since its original introductions in the 1980s. Low temperature in winter is a limiting factor in the geographic expansion and successfully establishment for apple snail populations. There have been some studies on population level of low temperature tolerance for P. canaliculata, yet little is quantified about its life‐history traits in responses to cold temperatures. Whether these responses vary with the acclimation location is also unclear. We investigated the survivorship and longevity of P. canaliculata in responses to cold temperatures and examine whether these responses vary with the location and snail size. We hypothesized that survival of the snails depends on their shell height and the level of low temperature, and P. canaliculata population from the mid-subtropical zone may exhibit the highest viability over the cold thermal range.
2. We sampled P. canaliculata populations from five latitude and longitude ranges of subtropical China: Guangzhou population in southernmost (SM‐GZ), three populations of Yingtan (MR‐YT), Ningbo (MR‐NB), Ya'an (MR‐YA) in midrange, and Huanggang population in northernmost (NM‐HG) subtropical zone. For each P. canaliculata population, survival and longevity at six cold acclimation temperature levels (12, 9, 6, 3, 0, and ?3°C) were quantified, and the effects of location and shell height were examined.
3. The MR‐YA population from mid-subtropical zone of China exhibited the highest survival rate and prolonged survival time regardless of the temperature acclimation treatments, whereas the SM‐GZ population from southern subtropical was the most sensitive to cold temperatures, particular temperatures below 9°C. No individuals of the SM‐GZ population could survive after stressed for 30 days (3°C), 5 days (0°C) and 2 days (?3°C), respectively. For each experimental P. canaliculata population held at 3, 0, and ?3°C, individuals with intermediate shell height of 15.0–25.0 mm had significantly higher survivals.
4. The results highlight a request of a more thorough investigation on acclimation responses in each of the life table demographic parameters for P. canaliculata, and pose the question of whether natural selection or some genetic changes may have facilitated adaptation in invasive locations.

     

基于享乐价格-结构方程双模型的西宁城市湿地生态系统服务价值及影响因素研究

湿地为城市发展提供巨大的生态系统服务，但其被市场“认可”的经济价值难以准确评估。以青海省西宁市城市湿地为例，筛选房屋结构、可达性、环境、湿地等10个因子，采用享乐价格模型对110个湿地周边社区样点的因子数据(2020年)进行分析，定量分析城市湿地被市场“认可”的价值量。采用断裂点理论和加权Voronoi图模型方法等，分析了湿地生态系统服务价值的空间影响范围；构建了湿地生态系统服务价值影响因素的结构方程模型，探究了影响湿地生态系统服务价值的主要因素。结果表明：(1)2020年湟水城市湿地的总价值达到3.367亿元，约有54.3%的生态系统服务通过房产被市场转化；(2)湟水湿地单位面积的生态系统服务价值为151.916元/m~2,生态系统服务价值由大到小排列：火烧沟(1.632亿元)>海湖湿地(0.710亿元)>宁海湿地(0.629亿元)>北川湿地(0.330亿元);(3)湿地生态系统服务价值占房产总价值的比例达到2.04%,位列10个因素中的第7位；线性函数模型结果显示，购买者对湿地的边际支付意愿是0.12元/m~2,即购买者愿意为房产与湿地之间的距离每缩小1m而多支付...     

基于环境库兹涅茨曲线的我国大气污染防治重点区域环境空气质量与经济增长关系研究

改革开放以来，中国经济迅猛发展，但大气污染等环境问题日益突出。进入21世纪，我国通过颁布实施多项大气污染防治政策，将京津冀及周边地区、长三角地区、珠三角地区等大气污染较严重的区域划定为重点区域，针对性制定治污措施和实施减排工程，努力推动区域环境空气质量改善。基于2000-2019年我国31个省（自治区、直辖市）（以下简称31个省份）GDP，以及SO₂、PM₁₀、NO₂三项大气污染物浓度数据，利用环境库兹涅茨曲线（EKC，Environmental Kuznets Curve）模型，对31个省份和京津冀及周边地区、长三角地区、珠三角地区的经济增长情况、大气污染物浓度演变以及二者之间的关系进行了系统全面的分析评估。研究结果显示：（1）近年来实施的各项大气污染防治政策，特别是2013年以来颁布实施的《大气污染防治行动计划》《打赢蓝天保卫战三年行动计划》，推动环境空气质量改善的同时，促进了经济发展与环境保护长期关系协调性逐步增强，除NO₂浓度呈U型外，31个省份SO₂浓度、PM₁₀浓度与人均GDP的EKC曲线呈倒U型和倒N型，并处于快速下降阶段。（2）京津冀及周边地区SO₂浓度与人均GDP呈倒U型，且处于快速下降阶段；PM₁₀和NO₂浓度均呈现U型关系，且均处于上升期。（3）长三角地区SO₂、PM₁₀浓度与人均GDP呈现倒U型和U型，但均处于下降阶段；NO₂浓度与人均GDP无相关关系。（4）珠三角地区SO₂、PM₁₀和NO₂浓度与人均GDP均呈现倒U型关系，且均处于下降阶段。为此，建议"十四五"期间我国政府要继续实施新一轮的大气污染防治行动计划，聚焦机动车NO_x污染管控，大力推动NO₂浓度稳步下降，以实现我国环境空气质量持续改善，为统筹经济高质量发展和生态环境高水平保护奠定坚实基础。     

Screening,cloning, enzymatic properties of a novel thermostable cellulase enzyme,and its potential application on water hyacinth utilization

International Microbiology - Cellulose is the cheapest, natural, renewable organic substance that is used as a carbon source in various fields. Water hyacinth, an aquatic plant rich in cellulose,...     

Antioxidant Activity and α-Glucosidase Inhibitory Activities of the Polycondensate of Catechin with Glyoxylic Acid

In order to investigate polymeric flavonoids, the polycondensate of catechin with glyoxylic acid (PCG) was prepared and its chemically antioxidant, cellular antioxidant (CAA) and α-glucosidase inhibitory activities were evaluated. The DPPH and ABTS radical scavenging activities and antiproliferative effect of PCG were lower than those of catechin, while PCG had higher CAA activity than catechin. In addition, PCG had very high α-glucosidase inhibitory activities (IC₅₀ value, 2.59 μg/mL) in comparison to catechin (IC₅₀ value, 239.27 μg/mL). Inhibition kinetics suggested that both PCG and catechin demonstrated a mixture of noncompetitive and anticompetitive inhibition. The enhanced CAA and α-glucosidase inhibitor activities of PCG could be due to catechin polymerization enhancing the binding capacity to the cellular membrane and enzymes.