中国栅蛛属2新种记述(蜘蛛目:栅蛛科)

本文记了分别采自云南高黎贡山的栅蛛科栅蛛属Hahnia 2新种:垭口栅蛛,新种S.yakouensis sp.nov.和肾形栅蛛,新种S.reniformis sp.nov..垭口栅蛛后眼列前曲,交媾腔大,扁圆形,交媾孔1个,位于交媾腔下缘,交媾管粗,呈"人"字形下行分成2支再向两侧扭曲.纳精囊有一肓管斜向上伸出,鉴于上述特征而与Hahnia mridulae Tikader,1970不同.肾形栅蛛交媾孔2个,位于生殖厣腹面中央,纳精囊1对,大,肾形,插入器始于生殖球左下方,鉴于上述特征而与Hahnia xinjiangensis Wang et Liang,1989不同. Abstract： The present paper deals with two new species of the genus Hahnia collected from the Gaoligong Mountains Region of Yunnan Province, China: Hahnia yakouensis sp. nov., Hahnia reniformis sp. nov..     

注重发挥博士后科研生力军作用

中国医科大学博士后科研流动站始建1995年。目前学校设有基础医学、临床医学和生物学3个博士后科研流动站。但由于每年国家财力有限,资助名额很少,在有限条件下建立、健全博士后制度,加强对博士后人员的培养,调动博士后人员的积极性是一项重要的研究课题。     

遗传物质的发现者之一——麦卡锡

1944年,3位科学家艾弗里、麦卡锡和麦克劳德在DNA遗传本质方面的发现是20世纪最重要的发现之一,这个发现打开了生物学革命的大门,从而改变了人类对自然界的看法,这项研究还为1953年沃森和克里克DNA双螺旋结构的发现奠定了坚实的基础,但不幸的是3位科学家都未曾荣获诺贝尔奖.通过介绍麦克林·麦卡锡的科学研究,从而对这项发现的基本状况有一个基本的了解.     

生命之树与进化模式:导言

One and half centuries ago, Charles Darwin (1859) presented overwhelming evidence and argued that all life on the earth shared common descent, and "from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved". Ernst Haeckel (1886) and several of his contemporaries attempted to trace the pattern of descent among all extant and extinct forms in what Darwin referred to as "the great Tree of Life". Ever since then, systematists and evolutionary biologists have been exploring morphological, cytogenetic, chemical, developmental and molecular characters, and actively developing theories and methods to infer phylogenetic relationships among organisms from these characters. This endeavor has been especially stimulated by the rise of molecular biology and the emergence of computer science over the past 50 years. At the beginning of the 21st century, we are presented with an unprecedented opportunity to reconstruct the entire Tree of Life, and further, to study evolutionary processes and mechanisms in the context of a robust phylogenetic framework.     

我国微生态学的奠基人——魏曦

魏曦,字东升,1903年12月25日出生于湖南岳阳一个小职员家庭,父亲任职于邮政局.1914～1921年他在家乡湖滨中学读书,毕业后考入长沙湘雅医学院,学习两年后曾参加北伐军,任第四集团军警卫团三等军医.后退出军队,在长沙广雅中学任教.1928年入设立在上海的中央大学医学院(1932年独立为上海医学院)学习,1933年毕业,获博士学位.     

高黎贡山北段东西坡种子植物区系的比较研究

高黎贡山北段的东西坡由于在降雨量和热量分配等方面存在着显著的差异,致使东西坡在植物的种类、组成及区系特征等方面表现出明显的差异.东坡记载野生种子植物152科,580属,1475种及192变种(亚种),西坡记载野生种子植物162科,659属,1804种及186变种(亚种).东西坡种子植物科、属、种的对比分析表明:1)东西坡现代种子植物区系具有相同的历史渊源,但其区系联系减弱了,东西坡区系相似性程度,依科、属、种的顺序依次递减;2)西坡现代种子植物区系比东坡具有更为深刻的热带起源烙印.就科、属、种三个水平来说,东坡的热带成分低于西坡,温带成分高于西坡.许多典型的泛热带大科在西坡比东坡有着更为丰富的种类,其中有些泛热带科分子在东坡缺乏分布,而在西坡找到了合适的驻留之地;3)西坡现代种子植物区系与东喜马拉雅植物区系的联系比东坡紧密,而东坡与高黎贡山以东的区系联系比西坡密切,由于高黎贡山山脉的阻隔,近代植物物种的东西坡交流发生了障碍;4)西坡生态地理环境比东坡更有利于物种的生存、繁衍和分化,它既是古老成分的避难所,又是孕育新生成分的摇篮.     

用叶绿体ndhF和核核糖体ITS序列推断李属(蔷薇科)的系统发育

Sequences of the chloroplast ndhF gene and the nuclear ribosomal ITS regions are employed to reconstruct the phylogeny of Prunus (Rosaceae), and evaluate the classification schemes of this genus. The two data sets are congruent in that the genera Prunus s.l. and Maddenia form a monophyletic group, with Maddenia nested within Prunus. However, the ndhF data set is incongruent with the ITS data supporting two major groups within Prunus one consisting of subgenera Laurocerasus (including Pygeum) and Padus as well as the genus Maddenia and another of subgenera Amygdalus, Cerasus, and Prunus. The ITS data, on the other hand, support a clade composed of subgenera Amygdalus and Prunus and Prunus sect. Microcerasus in addition to a paraphyletic grade of subgenera Laurocerasus and Padus (and the genus Maddenia) taxa. In general, the subgeneric classifications of Prunus s.l. are not supported. The ITS and ndhF phylogenies differ mainly in interspecific relationships and the relative position of the Padus/Laurocerasus group. Both ITS and ndhF data sets suggest that the formerly recognized genus Pygeum is polyphyletic and that the distinction of the subgenera Padus and Laurocerasus is not supported. The biogeographic interactions of the temperate and tropical members in the Padus/Laurocera- sus/Maddenia alliance including Pygeum are shown to be highly dynamic and complex.     

途经甘肃的3种水鸟新纪录

2007年10月13日至11月5日进行敦煌市湿地鸟类调查时,分别在南湖湿地与候鸟自然保护区及党河水库使用Leica apo77高倍望远镜观察到3种水鸟,在以往的文献资料中未见其分布于甘肃的报道,应为甘肃鸟类新纪录。笔者用500mm镜头分别拍下3种水鸟的照片。1.赤颈(Podiceps grisegena)2007年10月13日13:30时,在南湖湿地与候鸟自然保护区的阳关水库(渥洼池)记录到2只赤颈。当时水面上同时有凤头(P.cristatus)、黑颈(P.nigricollis)以及大量鸭类、潜鸭类游禽活动,赤颈体形较凤头小,而又明显比黑颈大。其中一只赤颈的…     

鸡的瞬膜

瞬膜(nictitating membrane),又称第三眼睑,是一种保护眼球、防止灰尘的结构.鸟类的瞬膜位于眼眶的前眼角,为半透明的膜,其内缘具有一种羽毛上皮,借以刷洗角膜上的灰尘.在飞行时能遮覆眼球,以避免干燥气流和灰尘对眼球的伤害.由于瞬膜在鸟类睁眼的一瞬间迅速缩回前眼角,很难拍摄到.最近费了好大的周折,终于拍到了理想的鸡瞬膜照片,现予以发表供生物学界的同行共享(友情提示:如引用请注明原作者).     

Reproductive response of generalist and specialist aphid morphs with the same genotype to plant secondary compounds and amino acids

Many studies have paid particular attention to the role of either secondary plant compounds or amino acids as determinants of host-plant range in phytophagous insects. Here we examine the relative importance of both of these classes of compound in host acceptance by generalist and specialist morphs of the black bean aphid, Aphis fabae, that are morphologically similar and genetically identical. Eleven secondary plant compounds and six amino acids with known biological activity in aphids are presented to insects within an artificial membrane system as single compounds, mixtures of same-class compounds and combined mixtures of the two classes of compound. It is found that 1) when specific single secondary compounds and amino acids are presented to generalist and specialist morphs of A. fabae, differential responses are exclusively consistent with plant-use strategy for amino acids but not for secondary compounds, 2) neither secondary compound nor amino acid mixtures give reproductive responses entirely consistent with plant range, but the response to secondary compounds is broadly consistent with plant range whereas the response to amino acids is not, 3) when secondary compounds and amino acid mixtures are combined, the response to secondary compounds generally dominates that to amino acids. Some scenarios of plant-range determination by secondary plant compounds and amino acids, suggested by results, are discussed.     

Ingestion of plant secondary compounds causes diuresis in desert herbivores

Plant secondary compounds are recognized deterrents and toxins to a variety of herbivores. The effect of secondary compounds on water balance of herbivores is virtually unexplored, yet secondary compounds could potentially cause a decrease in an animal's ability to maintain water balance. We investigated the effects of secondary compounds, alpha-pinene and creosote resin, on water balance in three species of herbivorous woodrats (Neotoma stephensi, N. albigula, N. lepida). In separate experiments, we measured the effect of these secondary compounds on voluntary water consumption, urine volume and urine osmolarity. In both experiments, water intake and urine volume increased and urine osmolarity decreased compared to controls. Water balance of specialist or experienced woodrats was less affected than generalists and woodrats with less prior experience with particular secondary compounds. Our results suggest that secondary compounds have diuretic-like effects on herbivores. Woodrats live in arid habitats with limited access to freestanding water; thus an increase in water requirements may have profound consequences on foraging behavior and fitness.     

The ecological role of secondary lichen substances

Considerable evidence, both direct and indirect, supports the hypothesis that many lichen secondary substances have significant ecological roles. Thus secondary chemistry may be important in determining the relative ecological success of individual lichen species and thus the structure and diversity of natural lichen communities. Primary ecological roles of secondary lichen substances can be classified into four groups: light-screen compounds, chemical weathering compounds, allelopathic compounds, (including antibiotic compounds), and anti-herbivore defense compounds.     

植物对植食性哺乳动物的化学防卫

综述植物次生合物防卫植食性哺乳动物食的研究进展,植物组织的次生化合物主要为酚类、萜类及含N类化合物,植物对动物觅食的化学防卫对策以次生化合物的各类而有差异,次生化合物通过对动物的食物摄入、消化、代谢,以及敏殖活动的效应,以抵御动物的觅食。将植物化学防卫与动物适应对策相结合,探讨动物－植物协同进化模式,是该研究领域的主要发展趋势。     

粘细菌次生代谢产物中大环类化合物的研究进展

粘细菌可以产生多种次生代谢产物,是继放线菌、芽胞杆菌之后的第3大类次级代谢产物产生菌。本文综述了粘细菌次生代谢产物中大环类化合物的研究进展。首先介绍了粘细菌中分离的主要大环类化合物种类、结构特征及来源菌株;然后分别从抗肿瘤、抗菌、抗病毒等几方面对其生物活性进行概述;最后对粘细菌次生代谢产物中大环类化合物的相关研究工作进行了展望。     

Secondary metabolites and plant/environment interactions: a view through Arabidopsis thaliana tinged glasses

Arabidopsis thaliana is a successful model plant for studying wide‐ranging topics including plant development, genetics and pathogen resistance. In addition, significant research has been conducted in the area of secondary metabolite biochemical genetics. The secondary metabolites in Arabidopsis include glucosinolates, terpenoids, phenylpropanoids, the alkaloid‐like camalexin, and other uncharacterized compounds. The genetic tools developed in studying secondary metabolite biochemistry are now being used to study how secondary metabolites control various biological processes. This includes compounds involved in plant/insect and plant/pathogen interactions, compounds preventing UV‐B damage, and compounds involved in hormone homeostasis. This review will describe what light Arabidopsis is shedding on the biological and ecological importance of specific secondary metabolites.     

Alkaloid Uptake Increases Fitness in a Hemiparasitic Plant via Reduced Herbivory and Increased Pollination

It has been historically difficult to manipulate secondary compounds in living plants to assess how these compounds influence plant-herbivore and plant-pollinator interactions. Using a hemiparasitic plant that takes up secondary compounds from host plants, I experimentally manipulated secondary compounds in planta and assessed their effects on herbivores and pollinators in the field. Here, I show that the uptake of alkaloids in the annual hemiparasite Castilleja indivisa resulted in decreased herbivory, increased visitation by pollinators, and increased lifetime seed production. These results indicate that resistance traits such as alkaloids can increase plant fitness directly by reducing herbivore attack and indirectly by increasing pollinator visitation to defended plants. Thus, selection for production of secondary compounds may be underestimated by considering only the direct effect of herbivores on plant fitness.     

Plant Secondary Compounds as Diuretics: An Overlooked Consequence

Plant secondary compounds are deterrents and toxins to a varietyof herbivores. The effect of secondary compounds on water balanceof herbivores is virtually unexplored, yet many secondary compoundsare renowned for their diuretic effects in humans and laboratoryrats. We review data from the ethnopharmocological literatureon plants with diuretic effects. We also present our data fromexperiments on water intake of specialist (Neotoma stephensi)and generalist woodrats (N. albigula) consuming plant secondarycompounds from their natural diet. We measured effects of dietarysecondary compounds on voluntary water consumption, urine volumeand urine osmolarity. Ingestion of secondary compounds increasedwater intake and urine output and decreased urine osmolarityin both species. However, the generalist was more impacted bydietary secondary compounds than the specialist. Our resultscombined with that from the literature suggest that diuresismay be a prevalent consequence of ingestion of secondary compounds.Many herbivores live in arid habitats with limited access tofree-standing water, thus an increase in the desire for watermay have profound consequences on foraging behavior and fitness.     

How do herbivorous insects cope with noxious secondary plant compounds in their diet?

Herbivorous insects use a variety of physiological mechanisms to cope with noxious (i.e., unpalatable and/or toxic) compounds in their food plants. Here, I review what is known about this coping process, focusing on one species of caterpillar, the tobacco hornworm (Manduca sexta). Herbivorous insects possess both preingestive (i.e., chemosensory) and postingestive response mechanisms for detecting plant secondary compounds. Stimulation of either class of detection mechanism inhibits feeding rapidly by reducing biting rate and/or bite size. This aversive response is highly adaptive during encounters with secondary plant compounds that are toxic. The insect's dilemma is that many harmless or mildly toxic compounds also activate the aversive response. To overcome this dilemma, herbivorous insects employ at least three mechanisms for selectively deactivating their aversive response to relatively harmless secondary plant compounds: (1) the presence of carbohydrates can mask the unpalatable taste of some secondary plant compounds; (2) prolonged dietary exposure to some unpalatable secondary plant compounds can initiate long-term adaptation mechanisms in the peripheral and central gustatory system; and (3) dietary exposure to toxic compounds can induce production of P450 detoxication enzymes. Thus, herbivorous insects utilize an integrated suite of physiological mechanisms to detect potentially toxic compounds in foods, and then selectively adapt to those that do not pose a serious threat to their growth and survivorship.     

Toxicity of secondary compounds to the seed-eating larvae of the bruchid beetle Callosobruchus maculatus

By incorporating various secondary compounds in the normal diet of larval Callosobruchus maculatus bruchids, we show that the effects of any particular compound are dosage-dependent. Alkaloids are generally the most toxic of the compounds tested. Non-protein amino acids are more toxic than protein amino acids but the latter can be toxic at 1 and 5% incorporation in the diet. The non-protein amino acid homoarginine has a salutary effect on larval survival at low concentrations. A variety of other secondary compounds found in seeds are toxic at various levels representative of those levels found in seeds in nature, and for all secondary compounds tested a 0.1–5% incorporation in the diet often has a detrimental effect on production of adult beetles. We conclude that many of the secondary compounds found in seeds are likely to be toxic to at least some animal, and thus are likely to be responsible at least in part for the extreme host-specifity shown by seed-eating insects.