关键词： Fragmocirrus espeletiae nov gen.   nov spec.   Sikorops espeletiae nov spec.   epiphytic ciliates   soil ciliates   testate amoebae   South America  

摘要： Ciliated protozoa from the giant rosettes of Espeletia trees (Compositae) and Espeletia soils were studied in four samples each from the Andean Paramo in Venezuela and Ecuador. Collections were analysed with the non-flooded Petri dish method, which reactivates the ciliates' resting cysts from air-dried samples. Species were identified by live observation and silver impregnation. Although most samples, especially those from soil, contained many testate amoebae, only 18 ciliate species could be found, indicating that the non-flooded Petri dish method was rather ineffective. Probably, ciliates from this region do not make "strong " (drought resistant) resting cysts because of the humidity of the habitats. Most of the ciliate species recorded are common in litter and soil world-wide. However, two of them are new: Sikorops espeletiae nov, spec. and Fragmocirrus espeletiae nov. gen., nov. spec. Both species are described in detail, including ontogenesis of F. espeletiae. Two other as yet insufficiently known species are redescribed: Arcuospathidium muscorum (Dragesco & Dragesco-Kerneis, 1979) and Gonostomum affine (Stein, 1859).

关键词： retina   horizontal cells   capillaries   glial fibrillary acidic protein   Tupaia belangeri (Scandentia)  

摘要： Previously, ultrastructural evidence has been presented that, in the retina of adult Tupaia belangeri, the perikarya and processes of horizontal cells extensively ensheath the basal lamina of capillary cross sections located between the inner nuclear layer and the outer plexiform layer The present study tests whether these horizontal cells can be further characterized by applying a polyclonal antibody against glial fibrillary acidic protein (GFAP). GFAP-immunoreactivity was noted in the astrocytic plexus ensheathing retinofugal axons in the nerve fiber layer. The vitreal endfeet and parts of the trunks of Muller cells were also labelled. Moreover, a large subpopulation of vessel-contacting horizontal cells was strongly GFAP-immunoreactive. Immunoreactivity was found in the perinuclear cytoplasm and in the sturdy primary dendrites of these cells. The somata of GFAP-immunoreactive horizontal cells were unevenly distributed. These cells had three to seven primary dendrites that showed considerable overlap with the dendrites of neighbouring horizontal cells. For these reasons, GFAP-immunoreactive horizontal cells were classified as belonging to the mammalian type A. Whether the simultaneous occurrence of two glial features, viz. extensive ensheathment of retinal capillaries and immunoreactivity for a polyclonal antibody towards GFAP, supports the view that retinal horizontal cells represent a cell type intermediate between neurons and glial cells is discussed.

关键词： Insects   Invertebrates   Metals   Heavy   Trees   Wood   Cadmium   Copper   Zinc  

摘要： RID=''ID='' Correspondence to: W. C. Ma http://***/link/service/journals/00128/bibs/0064002/*** [ABSTRACT FROM AUTHOR]

摘要： Collins reviews "Outside My Window: Birds," "Outside My Window: Trees," "Outside My Window: Flowers," and "Outside My Window: Mammals," all by Ernestine Glesecke.

关键词： Proechimys semispinosus   tree diversity   demography   frugivore   Panama  

摘要： Populations of the Central American spiny rat Proechimys semispinosus isolated on eight small islands in Panama were sampled monthly for 1 year to examine the relationships of demography to tree species composition and forest structure. Demography was characterized by calculating seven variables from the monthly census data. Tree species composition was determined by marking, measuring and identifying all trees greater than or equal to 10 cm in diameter at breast height (dbh) on each island. Forest structure (tree stature, density and species richness) was quantified by measuring seven variables at each of the 470 sampling stations. Bivariate correlations were computed between spiny rat demography and tree species composition and forest structure. To examine whether islands with more similar tree species composition or forest structure supported P. semispinosus populations with more similar demography, dendrograms based on complete-linkage cluster analysis were constructed. Spiny rat densities were correlated positively with the density of large-fruited fig trees and non-linearly to an index of forest age based on tree species composition. Spiny rat densities were not related to any structural variable. Dendrograms based on cluster analysis showed that spiny rat demography did not map onto forest structure, overall tree species composition or any group of selected tree species except figs Ficus spp. Thus, islands with more similar fig tree composition contained spiny rat populations with more similar demography. Tree species composition, which partly determines resource abundance, is apparently more important than forest structure in influencing spiny rat demography. Proechimys semispinosus has a temporally and spatially variable demography, and this flexible demography, in concert with an ability to use diverse resources, presumably promotes abundance and persistence in heterogeneous tropical forests and may contribute to the ubiquity of this rodent.

关键词： DNA   线粒体/遗传学   基因复制   遗传学   模型   遗传学   种系发生   软件   种特异性   动物   人类  

摘要： Paralogy is a pervasive problem in trying to use nuclear gene sequences to infer species phylogenies, One strategy for dealing with this problem is to infer species phylogenies from gene trees using reconciled trees, rather than directly from the sequences themselves. In this approach, the optimal species tree is the tree that requires the fewest gene duplications to be invoked. Because reconciled trees can identify orthologous from paralogous sequences, there is no need to do this prior to the analysis. Multiple gene trees can be analyzed simultaneously;however, the problem of nonuniform gene sampling raises practical problems which are discussed. In this paper the technique is applied to phylogenies for nine vertebrate genes (aldolase, ol-fetoprotein, lactate dehydrogenase, prolactin, rhodopsin, trypsinogen, tyrosinase, vassopressin, and Wnt-7), The resulting species tree shows much similarity with currently accepted vertebrate relationships. (C) 2000 Academic Press.

关键词： tree seedlings   acorns   rodents   spatial aggregations  

摘要： We investigated the degree to which the spatial distribution of oaks (Quercus robur L.) was related to habitat conditions, as reflected by vegetation type and structural features presumed to attract animal dispersers (trails, community borders). We hypothesized that the distribution pattern of oaks. with their potential to establish in many habitats, depends on the behaviour of the dispersing animals to a greater extent than micro-habitat conditions. One 100 m x 100 m plot was surveyed in each of two coniferous forests in east-central Sweden. No adult oak trees grew in the forests: all oaks were considered as dispersed into the plots by animals. We tested whether oak distribution was clumped with spatial autocorrelation analyses and whether oak distribution was related to vegetation type, species composition, tree cover, distance to nearest fertile oak tree. or distance to animal trails. Our study showed that oak trees were also spatially aggregated in a small-scale context. The spatial distribution of seedlings and older trees were associated with species richness and tree cover but not with any specific vegetation type, even though fewer oaks than expected grew in spruce forest habitats. Furthermore. we found that oak trees were associated with trails. There were differences in oak distribution between the two study sites in total number of oaks, the number of first-year seedlings, caches, and oak occurrence in relation to species richness and distance to nearest Fertile oak. Seed-dispersing animals seem to be of importance for oak distribution even though animal activities seem to differ between sites.

关键词： 链脲佐菌素,树鼯,糖尿病模型,患病率  

摘要： 目的 探讨链脲佐菌素（STZ）树鼩糖尿病（DM）动物模型的 空腹血糖（FBG）标准和最佳药物剂量。方法 将45只树鼩随机分 为正常对照组、STZ80、100、120、150 mg/kg组5个组，同时测 定其注药前、后的FBG，并于注药后第4、10周处死部分动物，取 胰腺做常规HE染色、淀粉染色和醛复红染色，光镜下观察其病理 变化，同时送电镜检查。结果 FBG≥11.1mmol/L的树鼩胰腺常规HE 染色中胰岛数量明显减少，胰岛直径也明显减小，胰岛β细胞数量 减少，肿胀;醛复红染色可见数量不等的β细胞脱颗粒，甚至无紫 红色颗粒;淀粉染色阳性，在β细胞周围有红色淀粉样物质沉着。 符合DM成模动物胰腺病理变化。正常对照组、STZ 80mg/kg组无 一成模;STZ 100mg/kg组有1只成模，患病率10％（1/10），但仅维 持1周即自然阴转;STZ 120mg/kg组有8只成模，患病率88.9％（8/9）， 但维持时间短，注药后第4周自然阴转率50％（4/8），第10周自然 阴转率100％（8/8），无一树鼩死亡;STZ 150mg/kg组有8只成模， 患病率88.9％（8/9），但维持时间长，注药后第4周自然阴转率37.5％ （3/8），第10周自然阴转率62.5％（5/8），注药成模后第6周有1 只树鼩死亡。结论 树鼩DM模型标准为FBG≥11.1mmol/L，最佳 STZ剂量为150mg/kg。

关键词： 李德   农业部饲料工业中心   中国农业大学   饲料工业   饲料业   加工工业   专家顾问   动物营养与饲料加工   动物科技学院   民族   权利主体   主任  

关键词： weta   invertebrate monitoring   Hemideina   indicator species  

摘要： Tree weta (Hemideina) are an important component of New Zealand forest ecosystems and have been identified as possible invertebrate indicator species in restoration programmes. We present designs for artificial weta roosts that have been used to monitor tree weta in Hawke's Bay for five years. A variety of invertebrates use the roosts including two species of Hemideina. Our data suggest that occupation of roosts may take a number of years, each roost monitors a very limited area, and that occupation by invertebrates fluctuates seasonally. We recommend that data from weta roosts be used primarily for temporal rather than spatial comparisons, and that installation of roosts takes place as far ahead of changes in management as feasible.