青蒿素衍生物SM486对小鼠运动神经末梢钠,钾流的抑制

青蒿素的某些衍生物已被作为救治脑型和抗药性疟疾的首选药物应用于临床，其中，一个含氮的水溶性衍生物ＳＭ４８６在动物实验中显示局部麻醉效应。本文报告它对运动神经末梢的Ｎａ＾＋，Ｋ＾＋通道的作用，实验于小鼠胸三角肌标本上进行，借助于一水浸物镜在放大４００倍显微镜下将微电极插至表层神经束的周鞘下间隙，记录神经末梢膜电流。     

Insect oviposition plasticity in response to host availability: the case of the tephritid fruit fly Bactrocera dorsalis

1. Insect oviposition behaviour is ecologically and physiologically plastic. For tephritid fruit flies, Bactrocera dorsalis Hendel, host availability varies spatially and temporally. Females are expected to adopt adaptive oviposition strategies to maximise lifetime reproductive fitness, including survival. Bactrocera dorsalis oviposition tactics in response to different host availabilities were investigated. 2. This study includes three treatments: (i) variable host densities (host density varied according to a fixed cycle from day to day over values of 1, 5, 10 and 20 hosts per cage), (ii) a fixed high host density (20 hosts per cage), and (iii) a fixed low host density (1 host per cage). 3. Daily egg‐laying number per female over the course of 27 days was entirely independent of host density and highly dependent on female age. As host availability increased, females accepted significantly more hosts, generally laid small egg clutches, and more broadly distributed the eggs. 4. Tephritid fruit flies adaptively adjusted egg clutches in ways that reflected the variability of host availability. Egg‐ and time‐limitation constraints appeared to drive these adjustments. Female egg maturation was triggered by oviposition activity and reflected marked lifetime trade‐offs. Such strategies involved specific time schedules for egg laying. 5.This study defined the oviposition plasticity of the tephritid fruit fly. These results have general implications for the behavioural ecology of insect herbivores and parasitoids.     

Characteristics of the Jejunal Microbiota in 35-Day-Old Saba and Landrace Piglets

The balanced microbiological system is a significant hallmark of piglet health. One of the crucial factors affecting intestinal microbiota is the host’s genetics. This study explored the difference in the diversity of jejunal microbiota between Saba (SB) and Landrace (LA) piglets. Nine Saba and nine Landrace piglets were fed with sow’s milk until day 35. Jejunal contents were harvested for 16S rRNA sequencing. The birth weight, body weight, and average daily gain of Saba piglets were lower than those of Landrace piglets (p < 0.01). Firmicutes were the main phylum in Saba and Landrace piglets, and the Saba piglets had a higher (p < 0.05) abundance of Bacteroidetes compared with Landrace piglets. The two most abundant genera were Lactobacilli and Clostridium XI in the jejunum of Landrace and Saba piglets. Compared with Landrace piglets, the Saba piglets had significantly lower (p < 0.05) abundance of Veillonella, Streptococcus, and Saccharibacteria genera incertae sedis. The functional prediction showed that “d-glutamine and d-glutamate metabolism” and “one carbon pool by folate” pathways were enriched in Saba piglets, while “limonene and pinene degradation”, “tryptophan metabolism”, and “sulfur relay system” pathways were enriched in Landrace piglets. In summary, the growth performance was higher for Landrace piglets compared with Saba piglets due to their genetic characteristics. The rich diversity and fewer infection-associated taxa were observed in Saba piglets, partially accounting for their higher adaptability to environmental perturbations than Landrace piglets. Furthermore, different pig breeds may regulate their health through different metabolic pathways.Key words: Saba piglets, Landrace piglets, jejunal content, the 16S rRNA gene, diversity     

Efficient computation of subset selection probabilities with application to Cox regression

An efficient method is presented to compute the probabilityof selection of a specified subset from the set of all subsetsof a fixed size where the subsets are taken from a populationwhose units have varying individual probabilities of selection.The problem is motivated by the computation of the exact marginallikelihood for the Cox proportional hazards model.     

基于肠-皮肤轴的益生菌改善脱发机制研究进展

随着人们生活压力的提升,许多男性在中年时期出现脱发,严重者甚至会出现斑秃、全秃现象,其中以雄激素脱发最为常见。雄激素脱发的发生主要由于头皮中睾酮(testosterone,T)及其代谢产物二氢睾酮(dihydrotestosterone,DHT)含量较多,其主要机制为毛囊中5α-还原酶将游离的T转化为活性更高的DHT,导致雄激素水平过高。雄激素水平过高会引起毛囊微小化,使毛发生长周期变短而产生脱发。基于肠-皮肤轴的理论,越来越多的研究表明益生菌(probiotics)能够改善或治疗脱发症状。通过益生菌调节肠道菌群的平衡,可促进体内毛发生长因子的表达和毛囊细胞的生长,改善由于压力过大或雄激素水平过高等因素引起的脱发症状。本文主要探讨益生菌与毛发生长的相关性,通过其对神经系统、免疫系统和内分泌系统的调节作用,对益生菌改善脱发的功能和机理进行综述,以期为研发改善脱发的食品和药物提供理论依据。     

江西老虎脑省级自然保护区鸟类资源调查

2017年11—12月、2018年7—8月、2018年11—12月,在江西老虎脑省级自然保护区开展鸟类资源调查,调查发现该保护区有鸟类17目53科240种。其中,非雀形目16目22科94种,雀形目31科146种。本区鸟类中有留鸟115种,冬候鸟57种,夏候鸟42种,旅鸟26种;古北界87种,广布种22种,东洋界131种。其中,国家重点保护鸟类31种,列入中国红色名录濒危等级(EN)物种有1种,黄胸鹀Emberiza aureola;易危等级(VU)物种有2种,白颈长尾雉Syrmaticus ellioti、白眉山鹧鸪Arborophila gingica;近危等级(NT)物种有19种。中国特有种4种,灰胸竹鸡Bambusicola thoracica、白颈长尾雉、白眉山鹧鸪、黄腹山雀Parus venustulus。多样性分析结果显示,该区鸟类群落Shannon-Wiener指数、Pielou指数分别为4.135、0.778,通过与周围包括武夷山、井冈山、齐云山、九连山4个保护区比较,显示研究区域物种种数较高。     

无人机技术在广州南沙区河涌景观特征生态调查中的应用研究进展

在城市化进程逐步加快、社会经济水平趋于高阶的时代,城市生态系统是当前开展交叉学科研究的重要对象,融合了自然科学(如林学、生态学等)和社会科学(如管理学、人文地理学等)领域的思想体系和研究方法。作为一种新兴技术,无人机遥感已在生物学、地理学、信息科学等多个学科领域广泛使用。主要从监测、研究、评估和保护等四个方面简要叙述了无人机技术在林业生态研究和管理中的应用情况,并以广州南沙区河涌景观为例简要分析了无人机技术在珠江三角洲地区城市森林景观中的实际应用。试图为我国城市区域的森林生态、生物多样性与人居环境研究和管理工作提供参考。     

Diverse oxyporine rove beetles from the Early Cretaceous of China (Coleoptera: Staphylinidae)

Two new genera and species, Protoxyporus grandis gen. et sp.n. and Cretoxyporus extraneus gen. et sp.n. , are described and figured on the basis of two well‐preserved impression fossils from the Lower Cretaceous Yixian Formation of China. The two genera display a combination of traits that are diagnostic of the extant staphylinid subfamily Oxyporinae: large and prominent mandibles, distinctly separated mesocoxae, abdominal tergites III–VII each with a pair of basolateral ridges, and abdominal intersegmental membranes with ‘brick‐wall’ pattern. Protoxyporus differs from extant Oxyporus in retaining the following plesiomorphic features: an elongate intercoxal process (or longitudinal carina) between metacoxae, relatively narrowly separated mesocoxae, less developed metaventral anterior process, and long infraorbital ridges. Cretoxyporus is morphologically very similar to Oxyporus, but retains distinct elongate infraorbital ridges. The discovery of two new oxyporine genera suggests that the early oxyporines were more diverse and their evolutionary history more complicated than previously documented. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:11503976‐D577‐45D2‐ACCB‐8226782EF817 .