杭州沼泽性水域原生动物群落变化规律

2005年4月-2006年3月调查了杭州市郊下沙区一个沼泽性水域原生动物群落的变化规律。共观察到各类原生动物265种,其中鞭毛虫114种,占原生动物总数的43%,其中植物性鞭毛虫占91%,动物性鞭毛虫仅占9%;肉足虫34种,占原生动物总数的13%,纤毛虫117种,占原生动物总数的44%。原生动物在此水域1个周年内的分布特征表现为植物性鞭毛虫种类多于动物性鞭毛虫,纤毛虫种类多于肉足虫种类。原生动物群落的结构参数(种类组成、个体丰度和多样性指数)因水质的变化而变化。此水域原生动物的优势种为梨形扁裸藻(Phacus pyrum)、旋转囊裸藻(Trachelomonas volvocina)、绿色裸藻(Euglenaviridis)和刺鱼状裸藻(Euglena gasterosteus),常年居留种为裸藻(Euglenasp.)、奇形扁裸藻(Phacus anomalus)、钟形虫(Vorticellasp.)、尾草履虫(Paramecium caudatum)和多态喇叭虫(Stentor polymorphrus)。全年3个采样站的Margalef生物多样性指数为1.056～6.054。     

哈尔滨人工湖泊中原生动物群落变化规律

2003年3月~2004年2月调查了哈尔滨人工湖泊原生动物群落多样性的变化规律,应用PFU法研究了原生动物群落季节变化演替的特征。共观察到各类原生动物120种,其中鞭毛虫53种,占原生动物总数的44%,肉足虫9种占原生动物总数的8%,纤毛虫58种占原生动物总数的48%,分析了原生动物在该湖的组成特点。原生动物在此人工湖泊中1个周年内的表现规律为植物性鞭毛虫多,动物性鞭毛虫少;纤毛虫多,肉足虫少。原生动物群落的结构参数(种类组成、个体丰度和多样性指数)因水质的变化而发生变化。在此湖中原生动物的优势种为喇叭虫属(S tentor)、眼虫属(E ug lena)、游仆虫属(E up lote)、隐滴虫属(C ryp tom onas),常年的居留种为眼虫属(E ug lena)、弹跳虫属(H a lteria)、侠盗虫属(S trobilid ium)、隐滴虫属(C ryp tom onas)。全年3个采样站的生物多样性指数在1.912~7.473之间。原生动物在1个周年中平均个体丰度出现的规律依次递减的顺序是秋季、夏季、春季、冬季。采样站1的平均个体丰度在四个季节中均高于采样站2、3。     

季节变化对沙漠生态系统土壤中自由生活线虫和原生动物间营养关系的影响

选择沙漠常绿灌木丛枝霸王(Zygophyllum dumosum)群落及群落间的开阔地带采样,研究土壤线虫和原生动物的种群大小、物种组成及营养结构.本研究共获线虫29属,裸变形虫33属90种;在所获各类原生动物中,鞭毛虫和纤毛虫均为食细菌类群,而鞭毛虫个体数量最多;在沙漠生态系统中,土壤湿度被认为是影响生物活性的最重要因素之一.然而,本研究显示:土壤湿度对线虫和原生动物是否重要取决于这些动物对土壤湿度的生理生态适应能力;土壤线虫和原生动物的体型大小、生活史策略和活动能力与土壤湿度的有效性相关不显著,但它们对微生物和微小土壤动物区系间的相互作用有重要影响,在干旱生态系统中,这种影响能够显著改变土壤生态系统短期的养分循环.本研究还表明,土壤线虫和原生动物种群间的关系主要取决于两者营养类群组成的变化.     

拒马河北京段原生动物群落特征及其对河流营养状况的指示

原生动物是水生生态系统中的重要组成部分,具有重要的生态功能。为揭示拒马河北京段的生态现状,作者于2004年3–11月对拒马河北京段9个采样点的原生动物群落进行了调查。共鉴定出原生动物310种,其中鞭毛虫134种(包括植鞭毛虫96种,动鞭毛虫38种),肉足类64种,纤毛虫112种。原生动物种类数较多的目有:眼虫目(39种)、动基体目(25种)、团鞭毛虫目(21种)、金滴虫目(21种)、下毛目(18种)、盾纤目(17种)、膜口目(15种)。优势种为卵形隐藻(Cryptomonasovata),次优势种为珍珠映毛虫(Cinetochilummargaritaceum)。9个采样点原生动物群落的Jaccard相似性系数介于0.4569和0.5950之间。通过对原生动物群落结构及营养功能类群的分析并与其他水域的资料相比较,认为目前拒马河北京段营养水平应介于贫营养和中营养之间。     

PFU原生动物群落生物监测的生态学原理与应用

原生动物是水生生态系统食物链中重要环节 ,发挥着十分重要的生态功能作用。在水环境质量变化评价与发展趋势预测中 ,与其它较高等生物类群比较 ,PFU原生动物群落在水质监测应用方面显示了诸多优点。系统地阐述了原生动物在水生生态系统中的地位与作用 ,重点介绍了原生动物评价水体污染的生态学基础及其优点和 PFU原生动物群落特征及其在水质监测应用中的优势。通过对国内外不同水质类型 PFU原生动物群落生物监测的典型案例研究 ,进一步论证了 PFU原生动物群落生物监测的生态学原理与应用优势     

对虾养殖池塘底质修复技术对原生动物群落结构的影响

在对虾养殖池塘水体中共检测到原生动物86种,其中纤毛虫48种;鞭毛虫25种,肉足虫13种。原生动物优势种主要由一些运动能力相对较弱或固着生长的种类组成,如褐砂壳虫（Difflugia avellana）、瓜形膜袋虫（Cyclidium citrullus）、透明鞘居虫（Vaginicola crystalline）、多态喇叭虫（Stentor polymorphrus）和种虫（Vorticella sp．）等,这些原生动物有以腐质和藻类为食、耐污性较强的特点。结果表明：在养殖初期,使用底质修复技术的试验池塘原生动物群落结构恢复比对照塘快,PFU群集的原生动物种类数和密度比对照塘多,水质比对照塘好,嗜污性相对较强的一些纤毛虫如尾草履虫（Paramecium caudaium）、拟瘦尾虫（Paruroteptus spp．）等比对照塘出现晚。在随后的养殖过程中,使用底质修复技术的试验塘原牛动物群落结构比对照塘稳定,原生动物种类数和密度起伏小,pH值、透明度变化幅度也小于对照池塘,没有发生病害,水质较对照塘好。     

雅鲁藏布江中游丰水期原生动物群落多样性及其影响因子

为了解雅鲁藏布江中游干流及支流丰水期原生动物的群落多样性特征,于2021年7月利用18Sr DNA高通量测序技术开展雅鲁藏布江中游原生动物多样性研究,并现场测定水体理化因子。结果表明:雅鲁藏布江中游原生动物在干流和支流两个河段上均以丝足虫门、纤毛虫门和双鞭毛虫门为主。群落Shannon多样性在河段间存在显著性差异; β多样性在两个河段上均以周转组分为主。研究区域原生动物群落存在显著的地理距离–衰减趋势;物种互作关系以协同作用为主导;影响支流原生动物群落的主要理化因子为pH、水温、海拔组合,影响干流原生动物群落的主要理化因子为电导率。原生动物群落受到地理距离、物种互作关系和理化因子的共同影响。本研究结果明确了雅鲁藏布江中游丰水期原生动物群落多样性变化特征及其驱动因素,可为后续雅鲁藏布江原生动物研究以及青藏高原水环境保护提供数据支撑和参考。     

淀山湖浮游动物的群落结构及动态

为帮助利用生物操纵技术进行淀山湖水体富营养化治理,2004年1月至2005年12月对淀山湖浮游动物群落结构,包括种类组成、种群动态、现存量进行了2周年的系统调查.淀山湖浮游动物有128种,其中浮游原生动物23属29种、轮虫23属51种、枝角类15属33种、桡足类15种.年均密度6 965ind/L,原生动物和轮虫分别占62.19%和36.77%,密度高峰出现在春季;生物量年均为6.00mg/L,以轮虫和枝角类占优势,分别占51.65%和38.38%,生物量高峰出现在夏季.4个类群浮游动物多样性指数H'与其均匀度指数J呈显著正相关,原生动物群落多样性指数H'与其密度呈显著负相关.根据浮游动物密度及优势种组成特征判断,淀山湖水质为富营养型.原生动物多样性指数具有较好的水质指示作用.     

珠江河口的浮游细菌生态学研究进展

河口地区是海陆交互作用的集中地带,生态环境十分脆弱敏感,物质循环机制复杂,而浮游细菌(bacterioplankton)参与的生态过程是河口生态系统物质循环的重要环节。珠江河口是独特的典型亚热带河口。近年的研究表明,浮游细菌在珠江河口生态系统物质循环中占有重要地位,其生产力和丰度受噬菌原生动物(鞭毛虫)和病毒的控制,而且其生物量与浮游植物的数量具有显著的相关性。珠江河口的优势浮游细菌类群为变型菌门(Proteobacteria)和蓝藻菌(Cyanobacteria)等,浮游细菌丰度和群落结构变化主要受到盐度、温度、营养盐水平等因素的影响。珠江河口浮游细菌与地球物质循环功能鲜有报道,而且珠江河口生态系统中有机质的浮游细菌转化机制和生态学效应更是没有深入研究。基于此,本文全面综述了珠江河口浮游细菌种类组成、分布、生物量、地球物质循环及其环境影响因素等方面的研究进展,有助于系统性地揭示近海生态系统的特征;同时,本文作者还对珠江河口浮游细菌生态学研究今后值得关注的科学问题进行了探讨。     

白洋淀原生动物群落多样性变化与水质关系研究

报道了大型浅水型湖泊原生动物群落变化与富营养化关系的研究,通过对华北平原最大淡水湖-河北白洋淀两个湖区9个采样站的初步调查,共鉴定出77种原生动物,其中43种为该湖首次记录：利用PFU原生动物群落结构和功能方法快速（两次实验的群集速度均为1d时间）监测了不同湖区的水质状况,水质分析及原生动物定性和定量调查结果表明,湖区Ⅰ（安州至枣林庄5个采样点）水体的污染程度明显大于湖区Ⅱ（圈头至端村4个采样站）,通过与20世纪50年代的调查资料比较,较好地反映了白洋淀富营养化的发展趋势。     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

---

Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

On the Dependence of the Quadratic Risk of the Classical Predictor and the Prediction-Horizon

When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418