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小麂、黑麂、赤麂精母细胞联会复合体的比较研究 总被引:6,自引:1,他引:6
本工作以界面铺张——硝酸银染色技术,对小麂(Muntiacus reeuesi)、黑麂(M.crinifrons)和赤麂(M.muntjak)的精母细胞联会复合体(Syna ptonemal complex,SC)进行亚显微结构的比较研究。结果表明: 1.SC的平均相对长度和臂比指数同有丝分裂细胞相应染色体的数值有很好的一致性。根据SC的相对长度和臂比指数绘制了三种麂的SC组型图。雄性黑麂减数分裂前期形成一个复杂的易位多价体,意味着其核型的演化过程涉及两次染色体易位和一次臂间倒位。 2.在减数分裂前期,性染色体的形态和行为同常染色体的有明显差异,如性染色体嗜银性较强,配对延迟等。XY的配对起始于早粗线期,在中粗线期,Y的全长均同X配对;XY-SC开始解体于晚粗线期。 3.在粗线期,X染色体未配对区域出现自身折叠,形成“发夹”状结构。这种“发夹”结构的形成,可能是在性染色体的进化过程中,X染色体通过不对称易位得到的重复片段在减数分裂前期同源配对的一种细胞学表现。 相似文献
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In 2003 and 2004, two series of projectile experiments were organized by P. Cattelain and ourselves at the CEDARC/Musée du Malgré-Tout (Treignes, Belgium). The experiments involved the use of two male ox calves and two female fallow deers as targets for bow and spearthrower shooting. Our main focus was a functional analysis of the antler projectile tips from the Upper Magdalenian layer of the Isturitz cave site (Pyrénées-Atlantiques, France). The study of the impact traces on the bones of the target animals was also included in the project; its results are presented here. The observation of these 127 traces led us to reconsider the nomenclature suggested by P. Morel, and to distinguish between three major traces: notches, punctures and perforations. Correlations appear between the nature of the trace and the shape of the bone (e.g., scapulae strongly associated to perforations), and the bone's mineral content: compared to adult long bones, immature long bones are much more easily perforated by projectile points, which usually remain firmly caught in them. However, our results do not show a clear distinction between the impact traces left by the bow and by the spearthrower. 相似文献
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Preliminary Study of the Effects of Impoundment of LG-2 Reservoir (James Bay Territory, Quebec) on the Net Seston and the Zooplankton of Impounded Rivers and Lakes The effects of impoundment on the biomass of net seston and zooplankton in lakes and rivers of Northern Quebec were investigated from 1978 to 1980, before, during and after the completion of LG2 Reservoir on the River La Grande (53° 54′ N, 76° 78′ W). In lotic stations, a 41–77% decrease in net seston was observed due to sedimentation of mineral particles (36–80 mg/m3 in 1978 to 10–21 mg/m3 in 1979). The ratio of organic to total seston increased from an average of 0.18 before the impoundment to 0.65 after. The flooding phase brought about a trophic upsurge; the biomass of the zooplankton increased by one to two orders of magnitude at the various sites; the greatest increases occurred in the central stations near the dam, the smallest in the upper stations near the inflow. In lake stations, no significant difference between years could be detected; the mean zooplankton biomass for all three years ranged from 6.59 mg/m3 to 34.34 mg/m3. Spatial variations between lakes were however significant. Results are compared with those in other natural lakes in Canada and reservoirs in the United States. Comparative examination of phytoplankton biomass before and after impoundment of LG2 Reservoir suggests that bacterioplankton and allochthonous organic material are key elements in the pelagic food chain after impoundment. 相似文献
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C. Ioriatti P. J. Charmillot et B. Bloesch 《Entomologia Experimentalis et Applicata》1987,44(2):123-130
Deux types de diffuseurs en caoutchouc (Michelin) et en plastique polystratifié (Hercon®) sont testés en laboratoire pour étudier quelques aspects des phénomènes de diffusion. Trois composantes phéromonales, le Z9-12: Ac, le 12: Ac et le Z9-14: Ac imprégnées dans ces différents supports servent à détermineer le rôle joué par la longueur de la chaîne de la molécule et la présence de doubles liaisons sur la vitesse de diffusion. L'influence de la température, de la vitesse du vent et de l'humidité est déterminée en cellules climatisées.Parmi les facteurs relatifs à la structure chimique, l'influence de la longueur de la chaîne est prédominante par rapport à la présence d'une double liaison. Parmi les facteurs climatiques, le vent agit plus que la température sur la diffusion, alors que l'humidité paraît secondaire. 相似文献
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Armin Heymer 《Ethology : formerly Zeitschrift fur Tierpsychologie》1968,25(7):829-833
Das Hinterleibsende der Anisopteren-Larven trägt drei, bei den Aeschniden besonders große, dreikantige Caudalstacheln, die den After umgeben und verschließen. Sie sind bei beiden Geschlechtern gleich gut entwickelt und werden gewöhnlich gespreizt getragen. Über ihre Funktion war bisher nichts bekannt. Aeschna-Larven, die man mit Trichopteren-Larven füttert, versuchen stets, die Beute von oben knapp hinter dem Kopf zu fassen. Die Abwehrbewegungen der Beute bringen den Räuber leicht aus dem Gleichgewicht. Er pendelt dann das Abdomen seitlich hin und her und schlägt plötzlich kräftig das Abdomenende gegen die Beute, zuweilen mehrmals, bis die Beute erlahmt. Die Caudalstacheln sind dabei eng zusammengelegt und werden gezielt tief in die Beute gestochen. Aeschna-Larven versuchen auch, im inner- und zwischenartlichen Kampf um eine Beute, sich gegenseitig die Caudalstacheln ins Abdomen zu stoßen. Der oft heftige Kampf endet erst, wenn die Beute zerreißt. 相似文献
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Patricia Benon Francois Blanc Brigitte Bourgade Pascal David Roger Kantin Michel Leveau Jean-Claude Romano Dominique Sautriot 《International Review of Hydrobiology》1977,62(5):631-648
Influences of unsalted waters penetration, in the Gulf of Fos, are marked as much on the primary step structuration level as on the component cellular physiology one. At their outlet, the weak structuration and the considerable biomasses resulting from an intense eutrophication go with a strong mortality clearly shown as well as by ATP/chlorophyll ratio than these of ATP, ADP and AMP inside the adenylic nucleotides pool. The primary step acquires a larger maturity in the salt share of the south eastern area. Spectrum variations of the population specific cellular volumes in terms of population importance can in a certain measure explain the intracellular rate variations into biochemical components. 相似文献
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Nicole Raynaud Brigitte Moreteau Nicole Chaminade et Gérard Nicolas 《Entomologia Experimentalis et Applicata》1985,39(1):43-46
Un apport unique de 10 g d'hormone juvénile 1, réalisé chez des criquets du dernier stade larvaire à corpora allata intacts ou préalablement soumis à une application de precocène 2, provoque, à la mue suivante, l'apparition d'individus dont les caractéristiques sont intermédiaires entre celles du dernier stade larvaire et celles de l'imago. Cependant, les criquets traités par le précocène 2 présentent des variations phénotypiques plus prononcées, se traduisant par un maintien accru des caractéristiques larvaires. Les études ultrastructurales montrent que les corpora allata dégénèrent rapidement sous l'action des 400 g de précocène 2.
Summary In fifth instar locusts, with intact corpora allata or previously subjected to precocene 2 action, a single injection of 10 g juvenile hormone 1 leads, at the next molt, to the appearance of individuals displaying characters ranging from the typical larval to the typical imaginal ones. But, unexpectedly, the phenotypic variations are more marked in the precocene 2 treated locusts, and are typified by an increased retention of larval characters. Electron microscopic studies indicate that the use of 400 g of precocene 2 rapidly leads to the degeneration of the corpora allata.相似文献
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Jean-Luc Boutry Monique Bordes 《Journal of experimental marine biology and ecology》1979,40(3):223-233
The results of three experiments dealing with the total lipids exchanged between the diatom Chaetoceros simplex calcitrans Paulsen and its surroundings are reported. Each study which involved four different culture samples and lasted 24 h has shown that the exchanges follow a definite rhythm with a period of 1 to 3 h, light being present or not. The increase of the total lipids in the medium through the agency of the diatom may be considerable after 24 h (4.66–4.75 mg/40 ml) but this amount is almost entirely regained by the algae, and sometimes more after nine days of culture. Using labelled dotriacontane-16,17-14C shows that labelled lipids are preferentially rejected by the diatom in the absence of light. 相似文献
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HIROMI TAKIZAWA EMILE VIVIER ANDRE PETITPREZ 《The Journal of eukaryotic microbiology》1975,22(3):359-368
RESUME. La Microsporidie Nosema bombycis, Protozoaire parasite agent de la pébrine du ver à soie, a étéétudiée cytochimiquement à la fois en microscopie photonique et électronique. Les examens ont porté sur la détection et la localisation des acides nucléiques (ADN et ARN), des polysaccharides, de la phosphatase acide, au cours des différents stades du développement dans les cellules de I'hôte (du schizonte à la spore). Les principaux résultats concernent les observations relatives aux polysaccharides et à la phosphatase qui ne sont détectés qu'au stade de la spore et ne sont pas observés au stade du schizonte. Les polysaccharides sont présents au niveau du sac polaire, du filament polaire et sur la membrane cytoplasmique; la phosphatase acide est localisée au niveau du sac polaire, du filament polaire et dans la vacuole postérieure. SYNOPSIS. Nosema bombycis, agent of pebrine disease of silkworm, was studied cytochemically, using both light and electron microscopy. Presence of nucleic acids (DNA and RNA), polysaccharides, and acid phosphatases was demonstrated and localization of these substances was determined in various stages of the parasite (from the schizont to the spore). DNA and RNA were detected in all these stages. Polysaccharides and acid phosphatase were found in the spore but not in the schizogonic stages. Polysaccharides were detected in the polar cap, the polar filament, and the limiting membrane of the cytoplasm of the spore. Acid phosphatase was found in the polar cap, the polar filament, and the posterior vacuole. 相似文献