中国脊椎动物2020年新增物种

为了及时掌握中国脊椎动物新增物种情况, 本文系统检索和整理了2020年发表的分类学文献, 汇总结果表明: 2020年中国脊椎动物共新增109种, 其中新物种100种, 国家级新记录种9种。包括鱼类新种24种、两栖类新种41种和新记录4种、爬行类新种30种和新记录4种、鸟类新种1种、哺乳类新种4种和新记录1种。上述新增物种中有92种描述报道时应用了分子遗传学证据, 占新增物种数量的84.4%。在新增脊椎动物物种中, 两栖类集中于无尾目、爬行类全部属于有鳞目, 分别有43种和34种, 其累计占比超新增物种总数的70%。在云南、西藏、湖南、贵州、四川等省区发现新物种数量较多, 均有10种及以上, 累计占比超新增物种总数的60%。绝大部分物种为中国学者发表, 绝大多数论文发表于英文期刊。总结数据提示今后需持续加强我国低等脊椎动物多样性的调查研究, 重视运用分子系统学技术进行物种识别。     

应用GeneXpert MTB/RIF对肺外结核的快速检测及评估

目的评估GeneXpert MTB/RIF检测肺外结核分枝杆菌的准确性,并与传统方法进行比较。方法选取2016年6月至2017年6月在本院就诊的144例疑似肺外结核病患者,对所有标本分别进行金胺“O”荧光染色镜检、液体培养及药敏试验、固体培养及比例法体外药敏试验和Xpert法检测。结果收集的144例疑似肺外结核标本中,确诊108例,以胸水、淋巴结活检和脓液感染较多,另36例阴性患者中,10例为非结核分枝杆菌感染。Xpert试验的敏感性为28.73%,特异性为96.00%,其阳性预测值和阴性预测值均高于其他3种检测方法。在阳性检出率方面,Xpert试验高于涂片镜检(χ~2=17.39,P0.05)、低于液体培养(χ~2=8.64,P0.05),而与固体培养之间差异无统计学意义(χ~2=2.56,P0.05)。固体培养、液体培养和Xpert试验3种方法对结核分枝杆菌利福平耐药率检测差异无统计学意义(P0.05),耐药率分别为8.33%、9.68%和11.11%,且Xpert试验方法检测出2株耐多药结核分枝杆菌,平均耗时2.5 h。结论 GeneXpert MTB/RIF可以作为一种筛选及快速检测工具应用于肺外结核的诊断,同时可作为检测MDR-TB的一种指标。     

中西部幼儿肠道菌群与膳食关系的比较

目的探究中部和西部地区幼儿肠道菌群的结构差异与膳食的关系,为幼儿营养健康状况监测和营养改善工作提供有效的营养干预。方法选择“贫困地区儿童营养改善项目”河南汝阳和贵州福泉,随机抽取107名汉族健康幼儿为调查对象,食物摄入采用24 h消费调查方法。应用高通量测序技术对肠道菌群进行测序和生物信息分析,研究两县幼儿肠道菌群差异。结果两县幼儿肠道菌群组成结构较为一致,但Alpha多样性分析表明,贵州福泉县幼儿肠道物种丰富度和多样性高于河南汝阳县。细菌属水平分析中,两县幼儿肠道内均以拟杆菌属、普雷沃菌、柔嫩梭菌和双歧杆菌属为主导的菌群结构,但河南汝阳县幼儿肠道双歧杆菌属和乳杆菌属丰度显著高于贵州福泉县(12.36% vs. 7.44%;0.19% vs. 0.03%)。结论中西部地区幼儿肠道菌群结构差异不大,但有益菌含量存在显著差异,这为研究肠道菌群与膳食及营养健康状况之间的关系提供了依据。     

基于日光诱导叶绿素荧光的北半球森林物候研究

植被物候是反映植被生长规律的重要指标, 对气候的反馈具有重要意义。日光诱导叶绿素荧光(SIF)通过复杂的能量耗散机制与光合作用相关联, 提供了从空间直接探测大范围植被物候的可能性。为了探究气候变化背景下SIF反演不同森林类型物候的适用性, 该文以北半球35个全球通量网(FLUXNET)森林站点为研究对象, 利用2007-2014年SIF值和总初级生产力(GPP)通过双逻辑生长模型和动态阈值法来估算3种典型森林类型的物候, 并采用相关性分析等方法评价SIF在估算不同森林类型物候时的差异性。主要结果为: 1) SIF对生长季开始时间(SOS)的估算精度高于生长季结束时间(EOS); 2) SIF能够更准确地估算混交林(MF)的SOS, 但是不能精确追踪落叶阔叶林(DBF)和常绿针叶林(ENF)的SOS; 3)春季季前短波辐射是驱动SOS的主要气候因素。综上, 建议在将来的研究中将SIF数据与其他遥感指数整合, 应用于不同植物类型的物候监测。     

湘西“蒿菜粑粑”原料植物鼠麴草总黄酮提取物体外抗氧化活性研究

为了解湘西特色食品“蒿菜粑粑”原料植物鼠麴草(Gnaphalium affine)总黄酮提取物体外抗氧化能力,采用DPPH、ABTS自由基清除实验,还原力实验和抑制β-胡萝卜素褪色实验等方法,测定鼠麴草总黄酮抗氧化活性。结果显示,鼠麴草总黄酮母液中总黄酮浓度为7.01 mg·mL–1mg/mL;总黄酮提取物对DPPH、ABTS自由基有较好的清除能力,其半数抑制浓度(IC50)分别为16.30 mg·L–1、30.16 mg·L–1,将胡萝卜素相对吸光度降为50%的时间延长至67.49 min,在还原能力、延缓胡萝卜素褪色和抑制脂质过氧化上也有较好效果。鼠麴草总黄酮提取物具有良好的体外抗氧化活性,可作为优质食用植物资源进一步开发与推广。     

Epithelial cell adhesion molecule promotes breast cancer resistance protein-mediated multidrug resistance in breast cancer by inducing partial epithelial–mesenchymal transition

Overexpression of breast cancer resistance protein (BCRP) plays a crucial role in the acquired multidrug resistance (MDR) in breast cancer. The elucidation of molecular events that confer BCRP-mediated MDR is of major therapeutic importance in breast cancer. Epithelial cell adhesion molecule (EpCAM) has been implicated in tumor progression and drug resistance in various types of cancers, including breast cancer. However, the role of EpCAM in BCRP-mediated MDR in breast cancer remains unknown. In the present study, we revealed that EpCAM expression was upregulated in BCRP-overexpressing breast cancer MCF-7/MX cells, and EpCAM knockdown using siRNA reduced BCRP expression and increased the sensitivity of MCF-7/MX cells to mitoxantrone (MX). The epithelial–mesenchymal transition (EMT) promoted BCRP-mediated MDR in breast cancer cells, and EpCAM knockdown partially suppressed EMT progression in MCF-7/MX cells. In addition, Wnt/β-catenin signaling was activated in MCF-7/MX cells, and the inhibition of this signaling attenuated EpCAM and BCRP expression and partially reversed EMT. Together, this study illustrates that EpCAM upregulation by Wnt/β-catenin signaling induces partial EMT to promote BCRP-mediated MDR resistance in breast cancer cells. EpCAM may be a potential therapeutic target for overcoming BCRP-mediated resistance in human breast cancer.     

Airborne and indigenous microbiomes co-drive the rebound of antibiotic resistome during compost storage

Composting is widely used to reduce the abundance of antibiotic resistance genes (ARGs) in solid waste. While ARG dynamics have been extensively investigated during composting, the fate and abundance of residual ARGs during the storage remain unexplored. Here, we tested experimentally how ARG and mobile genetic element (MGE) abundances change during compost storage using metagenomics, quantitative PCR and direct culturing. We found that 43.8% of ARGs and 39.9% of MGEs quickly recovered already during the first week of storage. This rebound effect was mainly driven by the regrowth of indigenous, antibiotic-resistant bacteria that survived the composting. Bacterial transmission from the surrounding air had a much smaller effect, being most evident as MGE rebound during the later stages of storage. While hyperthermophilic composting was more efficient at reducing the relative abundance of ARGs and MGEs, relatively greater ARG rebound was observed during the storage of hyperthermophilic compost, exceeding the initial levels of untreated sewage sludge. Our study reveals that residual ARGs and MGEs left in the treated compost can quickly rebound during the storage via airborne introduction and regrowth of surviving bacteria, highlighting the need to develop better storage strategies to prevent the rebound of ARGs and MGEs after composting.     

Amplification of RAD54B promotes progression of hepatocellular carcinoma via activating the Wnt/β-catenin signaling

Liver cancer was reported to be the sixth most frequently diagnosed cancer, and hepatocellular carcinoma (HCC) accounts for 75%-85% of primary liver cancer. Nevertheless, the concrete molecular mechanisms of HCC progression remain obscure, which is essential to elucidate. The expression profile of RAD54B in HCC was measured using qPCR and western blotting. Moreover, the levels of RAD54B in paraffin-embedded samples were evaluated using immunohistochemistry (IHC). The effect of RAD54B on HCC progression was testified by in vitro experiments, and in vivo orthotopic xenograft tumor experiments. The mechanisms of RAD54B promoting HCC progression were investigated through molecular and function experiments. Herein, RAD54B are dramatically upregulated in HCC tissues and cell lines both on mRNA and protein levels, and RAD54B can servers as an independent prognostic parameter of 5-year overall survival and 5-year disease-free survival for patients with HCC. Moreover, up-regulation of RAD54B dramatically increases the capacity for in vitro cell viability and motility, and in vivo intrahepatic metastasis of HCC cells. Mechanistically, RAD54B promotes the HCC progression through modulating the wnt/β-catenin signaling. Notably, blocking the wnt/β-catenin signaling axis can counteract the activating effects of RAD54B on motility of HCC cells. Besides, further analysis illustrates that DNA amplification is one of the mechanisms leading to mRNA overexpression of RAD54B in HCC. Our findings indicate that RAD54B might be a promising potential prognostic marker and a candidate therapeutic target to therapy HCC.     

The pollination of Habenaria rhodocheila (Orchidaceae) in South China: When butterflies take sides

Habenaria is one of the largest terrestrial genera in the family Orchidaceae. Most field studies on Habenaria species with greenish–white and nocturnal scented flowers are pollinated by nocturnal hawkmoths and settling moths. However, H. rhodocheila presents reddish flowers lacking a detectable scent and fails to fit the moth pollination syndrome. We investigated the pollinators, breeding system, and functional traits of H. rhodocheila in South China and found that two diurnal swallowtail butterflies Papilio helenus and Papilio nephelus (Papilionidae) were the effective pollinators. When butterflies foraged for nectar in the spur, the pollinia became attached between the palpi. A triangular projected median rostellar lobe was found at the entrance (sinus) of the spur of H. rhodocheila. This lobe divided the spur opening into two entrances forcing butterflies to enter their proboscides through the left or right side. When the projection of median rostellar lobe was removed, the site of pollinium attachment changed to the eyes of the butterflies, leading to a higher rate of pollinium removal but lower rate of pollinium deposition. Our quartz glass cylinder choice experiment suggested that visual rather than olfactory cues provided the major stimuli for butterflies to locate these flowers. Hand pollination experiments suggested this species was self‐compatible but pollinator‐dependent. However, the proportion of seeds with large embryos produced in self‐pollinated fruits was significantly lower than in cross‐pollinated fruits, indicating a significant inbreeding depression. Unlike many other orchid species, fruit set was higher than rates of pollinium removal, indicating a high level of pollination efficiency in a species with friable pollinia. Shifts from moth to butterfly pollination in the genus Habenaria parallel other orchid lineages providing insights into the potential for pollinator‐mediated floral trait selection.     

长江中下游岸带(宜昌-铜陵段)湿生植物的群落构建机制研究

沿长江中下游（宜昌-铜陵段）13座城市共37个位点,分别于丰水期和枯水期对岸带的湿生植物进行调查,从物种和系统发育2个维度研究群落的构建机制,并结合环境和空间因子探讨其驱动因素。结果显示：（1）丰水期湿生植物群落的α多样性高于枯水期,且丰水期α多样性主要与水分条件呈正相关,而枯水期则主要与温度和土壤总氮含量有关。（2）丰水期的系统发育结构指数呈聚集趋势,暗示生境过滤起着主导作用,而枯水期的NRI（net relatedness index）和NTI（nearest taxon index）呈不同趋势,暗示存在近期的群落分化。（3）群落的α多样性在物种层面和系统发育层面存在显著关联性,其多样性水平可在一定程度上互为表征。（4）长江中下游沿岸湿生植物群落的构建机制在不同时期存在差异,丰水期的群落构建是环境筛选和扩散限制共同作用的结果,且以环境筛选作用占主导,而枯水期的群落构建仅在物种层面受一定程度环境筛选作用的影响。（5）大生境的温度变化、微生境的土壤水分和养分条件是影响长江中下游岸带湿生植物群落差异的主要驱动因素。该研究结果可为长江中下游岸带湿地生态系统的管理和保护提供科学支持。