三疣梭子蟹蜕壳周期肝胰腺、外壳和鳃中钙含量的变化

研究测定了三疣梭子蟹蜕壳周期肝胰腺、鳃和外壳中的钙含量。结果显示,在不同时间,鳃中钙含量变化较小,各时间点差异不显著;蜕壳前期至蜕壳刚完成阶段三疣梭子蟹(软壳蟹)肝胰腺中钙含量最高,蜕壳后第4 d肝胰腺中钙含量最低。三疣梭子蟹外壳中钙含量随着外壳的硬化(钙化)逐渐增加,完全硬化后外壳中钙含量达到最高。研究表明,蜕壳后三疣梭子蟹肝胰腺中钙含量的降低与外壳的钙化之间具有关联性,肝胰腺在三疣梭子蟹蜕壳后钙的储存中起着重要作用,而鳃在钙离子储存中所起的作用可能小于钙转移的作用。     

东海三疣梭子蟹纳精囊形态结构与内含物的变化

2005～2006年通过定期采样,对东海三疣梭子蟹(Portunus trituberculatus)纳精囊的形态、组织结构、内含物及相应卵巢的发育状况进行了较为深入的研究.交配前期,4～6月份,纳精囊囊壁较薄,背腹囊腔分离;随后囊壁皱缩(7～9月份),背部囊壁上皮出现分泌层;最后囊壁增厚,单层多核柱状细胞消失,腔内只含琥珀色胶状物质.交配期(10～11月份),囊腔膨大,囊壁变薄.背部近交接处出现"凸"或"丁"字型突起;相应地,腹囊腔内亦出现含角质层褶皱.精子塞是三疣梭子蟹成功交配的特征,是雌雄梭子蟹共同作用的产物,由雄性基质、雌性分泌物、精子塞不定部分和精子塞半透明部分4种物质组成;精荚仅存于雄性基质中.三疣梭子蟹的精子塞在不到2个月的时间内消失殆尽,并不能保护和滋养精子.背部突起对调控纳精囊容积起主要作用,其形成与消退与精荚运输关系密切.交配后期(12月至翌年3月),纳精囊皱缩完全;裂解完全的精荚在背腹囊腔交接处集中,最后贮藏在腹囊腔内,为后续受精做好准备.纳精囊与卵巢关系紧密,进化上可能有重要意义.纳精囊与卵巢发育相联系,可以更好地反映三疣梭子蟹的资源动态.     

两种不同产地养殖三疣梭子蟹肌肉中营养成分比较分析

目的：评价不同产地养殖三疣梭子蟹（Portunus trituberculatus）肌肉的营养品质及其风味物质含量差异性。方法：采用生化分析方法,对浙江省台州市和山东省日照市三疣梭子蟹肌肉中的基本营养成分,以及氨基酸、脂肪酸、核苷酸及矿物质元素等营养物质的含量进行检测和对比分析。结果：山东省日照市养殖雌性三疣梭子蟹肌肉中脯氨酸含量显著高于浙江省台州市养殖雌性三疣梭子蟹（P＜0.05）;山东省日照市养殖三疣梭子蟹肌肉中SFA、MUFA和PUFA含量均显著高于浙江省台州市养殖三疣梭子蟹（P＜0.05）;山东省日照市养殖三疣梭子蟹肌肉中肌苷酸（IMP）和腺苷酸（AMP）含量均显著高于浙江省台州市养殖三疣梭子蟹（P＜0.05）;山东省日照市养殖雌性三疣梭子蟹肌肉中甜菜碱含量显著高于浙江省台州市养殖雌性三疣梭子蟹（P＜0.05）。结论：不同产地养殖三疣梭子蟹肌肉中营养成分含量存在一定差异,并对其风味及营养价值产生影响,可能与水域环境、遗传基因等因素有关。本研究可为三疣梭子蟹的品质评价及养殖繁育工作提供科学依据。     

云南新平哀牢山红瘰疣螈的陆地求偶交配行为模式

红瘰疣螈Tylototriton shanjing为云南山地环境中典型的有尾两栖类,其求偶交配行为模式尚未被系统研究。2013—2014年对云南省新平县哀牢山繁殖期红瘰疣螈在陆地环境中的求偶交配模式进行了观察。研究结果显示,红瘰疣螈的求偶交配行为是按照一定时序进行的,整个过程由定位、静止展示、劝导展示和精子转移4个阶段组成。在求偶交配中雄性个体行为包括:警戒、追逐、阻拦、蹑行、嗅探、轻推、诱导、扇尾、侧行和产精包等类型。雌性个体的行为包括离开、静止、跟随、纳精包等类型。雄性行为较雌性复杂,雄性在求偶交配行为过程中占据主动。雌雄的识别主要以视觉为主,整个求偶交配过程中无抱握行为,雄性尾部的运动也比较单一,这些行为的变化可能是对在陆地求偶交配的适应。     

三疣梭子蟹增养殖过程对野生种群的遗传影响——以海州湾为例

为探明三疣梭子蟹人工增殖与养殖活动对野生资源的遗传影响,本文利用20对SSR引物对海州湾三疣梭子蟹野生群体与两个养殖群体进行群体遗传结构和遗传分化研究。结果表明,野生种群遗传多样性明显高于养殖群体,其群体杂合度Ho为0.8509,而两个养殖群体的杂合度Ho分别为0.4525和0.5283。海州湾野生三疣梭子蟹的 Ne、Ho、He、PIC均显著高于两个养殖群体（P<0.05）但两养殖群体的 Ne、Ho、He、PIC均无显著差异（P>0.05）。以上结果说明海州湾天然三疣梭子蟹群体的遗传多样性显著高于养殖群体。三群体间遗传分化处于中度水平（Fst,0.1085~0.1448）,基因流Nm处于1.5-2.0间,野生群体与养殖群体的遗传分化比养殖群体内部之间大,基因流也较养殖群体内部之间要小,表明野生群体与养殖群体存在一定的分化,基因流处于中等程度。因此,当前海州湾天然三疣梭子蟹遗传状况良好,养殖活动和人工增殖放流对天然资源的遗传影响还很有限,这可能与海州湾人工养殖三疣梭子蟹时间较短、人工放流的规模较小、时间较短有关。     

雌性动物多次交配行为的机制及进化

雌性动物的后代数量不可能超过她的卵子数。在理论上, 一个生殖季节内, 一次或几次交配就足够使雌性所有卵子受精, 最大化其生殖潜能。但与理论预测相反, 许多物种的雌性经常与同一个或多个雄性发生多次交配。交配通常要付出较高的代价, 所以很难理解为什么雌性动物要反复进行多次交配。本文综述了解释此行为的一些适应性和非适应性假说。从获得直接收益和间接收益二个角度介绍了适应性假说。直接收益主要包括求偶喂食和“彩礼”、受精保证、亲代抚育、生殖刺激和护卫交配权等5 个方面。还着重介绍了多次交配对雌性后代的间接遗传受益, 即获得优质基因、提高后代遗传多样性和遗传互补性3 个假说。非适应性假说包括了遗传相关假说和顺从雄性行为假说。     

昆虫雄性生殖腺分泌物的功能

昆虫两性成功交配后,雄性生殖腺分泌物使雌性昆虫的生理和行为都发生了巨大的改变。昆虫雄性生殖腺分泌物含有多种具有生物活性的分子,这些生物活性分子通过成功交配转移到雌虫生殖道后,对雌虫的生殖活动产生影响,使交配雌虫一段时间内不再交配,使已转移的精子易于在雌虫生殖道内储藏,使卵与精子完成受精过程,还可刺激雌虫产卵和卵的发育,调控排卵和产卵等生殖过程。在精子的转移过程中,雄性生殖腺分泌物中的抗菌媒介质能使雌虫的生殖导管提供友好的环境。此外,一些昆虫的雄性生殖腺分泌物还含有一些有毒的化学物质,保护已产下的卵不被天敌取食和病原体侵染。     

三疣梭子蟹生长的初步研究

1.渤海南岸自5月底前后孵出的三疣梭子蟹溞状幼体,经约15—18天的培育,发育成第1期幼蟹,在20°—31℃的水温条件下,再经过约3个月的室内水池培养,到8月底前后,即开始陆续成熟。梭子蟹自第Ⅰ期幼蟹到达性成熟,雄蟹蜕壳8—10次,大部分为8次,成熟个体的体重达5.54—176.4克;雌蟹蜕壳9—10次,大部分为9次,成熟个体的体重达83.0—176.9克。第8次蜕壳的雄蟹交尾以后,当年还可以蜕壳一次。因此,当年长成的同一批梭子蟹群体中,雌雄个体的大小并无多大差异。 2.三疣梭子蟹每相邻两次蜕壳的间隔时间,随着龄期数的增加而渐趋拉长。如一般第Ⅰ期幼蟹前后蜕壳间隔为3—4天;第Ⅴ期为7—10天,第Ⅸ期为22天左右。但因其自身因素及环境因子的影响,其间隔时间也可能延长或缩短。 3.梭子蟹蜕壳多在夜间进行,通过对第7到第10次蜕壳活动的观察,自开始蜕壳到新个体脱离旧壳,一般需15—30分钟。 4.梭子蟹甲长、甲宽及体重的增长是不均匀、不连续的,随着蜕壳而产生的阶梯式的上升。蜕壳前后甲长和甲宽可增加30％左右,而体重则可成倍地增加。两次蜕壳之间,甲长与甲宽基本上无变化,鲜重略有增加,而干重的增加较为显著。 5.从室内池养群体抽样测定的结果分析,梭子蟹甲长与甲宽、甲长与体重和甲宽与体重之间,皆存在幂函数关系,其回归     

近距离交流信号对雌性凹耳蛙 抱对成功率的影响

繁殖期雌性凹耳蛙（Odorrana tormota）的声信号已有过深入的研究,但目前国内对其交配行为研究较少,近距离时,雌性凹耳蛙如何与雄蛙交流并完成抱对尚不清楚。为探究繁殖期雌性凹耳蛙与雄蛙近距离交流、交配过程,采用焦点动物取样法和全事件取样法对雌性凹耳蛙交配前行为进行记录。2013至2016年及2018年记录并分析了49组雌雄蛙抱对过程和42组未抱对个体的视频数据。结果表明,凹耳蛙雌蛙与雄蛙近距离交流过程涉及多种信号,包括视觉信号（眨眼、低头、腹部膨胀、脚趾震动、背转向雄蛙）与声信号两类;在每组雌蛙发出信号且抱对成功的实验中,各视觉信号出现1或2次较多,声信号出现1至3次较多,眨眼、鸣声、腹部膨胀三种信号的总次数较多;5个繁殖期所记录的雌蛙交流信号中视觉信号所占的比例均高于声信号。统计分析结果显示,同一只雌蛙在抱对成功与失败时所发出的眨眼、低头和腹部膨胀三种视觉信号的次数存在显著性差异（P < 0.05）,声信号、腹部膨胀、脚趾震动和背转向雄蛙这四种信号仅在抱对成功时出现。因此,推测这些信号在抱对前出现时,有助于提高雌雄凹耳蛙抱对成功率。     

室内饲养油棕象甲的行为观察

本文研究了油棕最有效的授粉昆虫油棕象甲Elaeidobius kamerunicus Faust的成虫交配、产卵行为,并对交配和产卵过程中发生的多种行为进行了描述。结果表明：油棕象甲一次完整的交配过程可以划分为交配前、交配、交配后三个阶段,在交配过程中雄虫会发生多次插入授精。油棕象甲一次完整的交配过程平均需要43733 s,其中授精前的抱对时间平均为2233 s,交配过程中每次授精插入时间平均为533 s,配后保护时间平均为8567 s。油棕象甲的卵为单产,在一朵油棕雄花内一般只产1粒卵,产卵前雌虫用喙在雄花上制造产卵孔,同时用触角辅助完成。观察油棕象甲幼虫取食和蜕皮等行为。     

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.

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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.