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1.
Resume Cette étude a pour but d'étudier les variations physiologiques et métaboliques tant au repos, qu'au cours d'efforts physiques de longue durée (2h) à 40% de la puissance maximale et d'efforts exhaustifs dans des conditions d'hypothermie ambiante (0C) en comparaison de valeurs recueillies en conditions thermiques neutres (20C). L'ensemble des épreuves furent exécutées en chambre climatique par: d'une part 11 sujets mâles pour l'effort exhaustif et d'autre part 8 sujets mâles pour l'exercice sous-maximal. Nous avons observé une légère bradycardie à 0C pour nos deux groupes à la fin de l'effort. La VO2 et la ventilation pulmonaire sont plus élevées à 0C lors de l'effort maximal, nous observons toutefois le phénomène inverse lors de l'exercice sousmaximal. Les concentrations plasmatiques en acide lactique sons moins élevées et les bicarbonates plus élevés en ambiance thermique froide pour les deux conditions expérimentales. Le pH et la température rectale demeurent stables. Le RQ ne présente pas de différences significatives à la fin de chacun des deux efforts à 20C et 0C.
The purpose of this study is to investigate the responses on cardiorespiratory and metabolic level measured at rest, during a long-term (2 h) submaximal exercise (P=40% Pmax) and during an exhaustive exercise (Vita Max) and recovery time in normal (20C) and in hypothermic (0C) conditions. The ergometric exercises were performed by 11 male subjects (Vita Max) and 8 male subjects (submaximal exercise) in a climatic room. We have observed a slight but mostly not significant (P<.05) bradycardia for both groups at the end of the exercise. VO2 and pulmonary ventilation are higher at the end of the maximal exercise performed at 0C, this phenomenon is reversed for the submaximal exercise. The lactate concentrations are lower at 0C. For the same temperature the bicarbonates are higher. pH and T rect are not different in both experimental conditions and RQ is not significantly affected by temperature variations.
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黑卵蜂(Telenomus theophilae Wu et Chen)的寄生行为(英语)   总被引:4,自引:0,他引:4  
本研究采用带电视摄录像系统的体视显微镜观察了黑卵蜂Telenomus theophilae wu et Chen的寄生行为.该种黑卵蜂的寄生系列行为可划分为5个连续的步骤:检查、探测、钻入、产卵和标记.此全过程平均需时17min 20 s,其中钻入和产卵的时间占86.5%.观察结果发现,雌蜂在首次寄生时有一个识别寄主的学习过程.该蜂对野桑蚕Theophila mandarina(Moors)卵的过寄生率,在第一粒寄主卵上是70.6%,而在第4粒卵上则为14.7%,前者为后者的4.8倍.  相似文献   

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Résumé L'ultrastructure des éléments cytoplasmiques de deux Dinoflagellés a révélé des différences fondamentales directement liées à leur mode de vie.Chez Noctiluca (Dinoflagellé libre, incolore), les corps de Golgi jouent un rôle important dans la formation des sphères archoplasmiques au moment des divisions et lors de l'élaboration de l'endoglée. Les mitochondries de grande taille, parfois géantes, ont des crêtes nombreuses et une matrice réduite. Elles offrent souvent des relations de contiguïté avec les granulations lipidiques et l'enveloppe nucléaire; elles sont très abondantes dans le tentacule du trophozoïte. Il n'existe pas de plastes. Les inclusions lipidiques abondent ainsi que les trichocystes fibreux et les poches mucifères dont le contenu est polysaccharidique.Chez Blastodinium (Dinoflagellé parasite, coloré sauf une espèce), les corps de Golgi sont très réduits dans le trophocyte, assez rares mais de structure classique dans les sporocytes. Les mitochondries sont de petite taille, pauvres en crêtes et ont une matrice importante chez le trophocyte; elles sont plus grandes dans les sporocytes. Les plastes bien développés, périphériques, possèdent des lamelles stromatiques formées de trois thylakoïdes chez les sporocytes; par contre, chez l'individu végétatif, le plus souvent incolore et relativement protégé de la lumière par plusieurs rangées de sporocytes, les plastes, de grande taille ont un aspect dégénéré: lamelles stromatiques rares, thylakoïdes tassés et stroma important; ce sont des étioplastes. Le cas de Blastodinium contortum hyalinum toujours incolore, est particulier: les plastes existent encore mais sont totalement dégénérés. Il y a très peu de lipides dans le trophocyte, mais ils sont par contre abondants dans les sporocytes. Il existe des trichocystes fibreux et chez l'individu végétatif, des figures myéliniques.Ces importantes variations structurales illustrent parfaitement, dans l'échelle évolutive des Dinoflagellés, l'exemple de deux modes de vie très différents.
Fine structure of endoplasm and vacuoles in two types of dinoflagellates of the genus Noctiluca and Blastodinium
Summary The fine structure of cytoplasmic elements of two Dinoflagellates reveals fundamental differences directly linked to their way of life.In Noctiluca, free-living, colourless dinoflagellate, the Golgi bodies play an important role in the formation of archoplasmic spheres at the moment of division and when the endoglea is elaborated. The mitochondria of great size, sometimes giant, have very abundant cristae and a reduced matrix. They often show relations of contiguity with the lipid granules and the nuclear envelope; they are very abundant in the tentacle of the trophozoïd. There are no plastids. The lipid inclusions are very abundant and so are fibrous trichocysts and muciferous bags whose content is polysaccharidic.In Blastodinium, parasitic dinoflagellate, coloured except for one species, the Golgi bodies are much reduced in the trophocyte, rather rare but of classical structure in the sporocytes. The mitochondria are of small size, with rare cristae and have an enlarged matrix in the trophocyte; they are bigger in the sporocytes. The plastids are well developed, peripheral, and have stromatic lamellae formed of three thylakoïds in the sporocytes. On the other hand, in the vegetative individual, usually colourless since it is protected from the light by many rows of sporocytes, the large plastids have a degenerated aspect, rare stromatic lamellae, packed thylakoïds and enlarged stroma; they are etioplastids. The case of Blastodinium contortum hyalinum, always colourless, is special: the plastids still exist but are completely degenerated. There are very few lipids in the trophocyte but abundant ones in the sporocytes. Some fibrous trichocysts occur, and in the vegetative individual, some myelinic vacuoles.These important structural variations illustrate very well the example of two very different ways of life, in the evolutionary tree of dinoflagellates.
Cet article fait partie d'un travail d'ensemble constituant une Thèse de Doctorat d'Etat intitulée: La cytologie et la division de deux types de Dinoflagellés: Noctiluca Suriray (genre libre) et Blastodinium Chatton (genre parasite).  相似文献   

5.
Acaulon fontiquerianum Casas et Sérgio (Pottiaceae) was found in the course of bryological research conducted in a coastal area of southeastern Sardinia. The ecological characteristics of the site and the current distribution of the species in the Mediterranean basin are reported.  相似文献   

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本文记述介形类Silenites属的3新种和1未定种,标本采自山西太原西山七里沟上石炭统太原组。关于Silenites属的系统分类位置,迄今还未确定,鉴于当前标本所显示的闭壳肌痕系由众多痕斑聚集成圆形;铰合构造在大瓣上为槽,小瓣上为脊,且光滑无齿;壳面光滑无饰;壳体侧视近三角形,高大于长之半;左壳大于右壳,周缘超覆等特征,笔者认为,Silenites属应归入Bairdiocyprididae科(Shaver,1961)。  相似文献   

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《Comptes Rendus Palevol》2002,1(7):491-498
The evaluation of d’Orbigny’s contribution to Bolivian studies implies putting it in relation with the economic and political context prevailing before, during, and after his travel in this country, between 1830 and 1833. This paper deals with the following topics: the crisis of the silver mines in Potosi, the achievements of the governments of Santa Cruz (1829–1839) and Ballivián (1841–1847), and the various projects intending to open Bolivian lowlands to navigation and colonisation. Finally, some important documents show that d’Orbigny remains concerned with Bolivia many years after he returned to France.  相似文献   

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Résumé Un phophopeptido-mannane a été isolé des parois de la levureSaccharomyces cervisiae, souche sauvage et mutant. Après traitement de ces éléments cellulaires par l'éthylène-diamine, la séparation des différents produits hydrosolubles par filtration sur gel a permis de recueillir ce phosphopeptido-mannane à l'état pur. Il est constitué de 91 à 93% de mannose, de 0.32–0.42% de N-acétyl glucosamine, de 0.9–1.3% de phosphate et de 6 à 7% d'acides aminés. L'étude structurale révèle que les unités mannose sont liées par des liens 16 et portent en position 2 des chaînes latérales formées d'oligomannosides deX mannoses liés en 12 et en 13 et que de petits oligosaccharides sont fixés à la sérine de la chaîne peptidique par des liaisonsO-glycosidiques tandis que des polysaccharides sont fixés à l'asparagine de cette chaîne peptidique par une liaison N-glycosidique faisant intervenir, la N-acétylchitobiose. Le mannane du mutant est moins ramifié mais davantage phosphorylé.
Isolation and structure of a surface phosphopeptido-mannan from the cell wall of Saccharomyces cerevisiae (wild strain and mutant)
Summary Treatment with ethylenediamine of the cell walls fromSaccharomyces cerevisiae released a phosphopeptido-mannan. It has been possible to isolate this glycoprotein in a pure state after separation of the different hydrosoluble products by gel filtration. This compound contained 91–93% mannose, 0.32–0.42% N-acetylglucosamine, 0.9–1.3% phophate and 6–7% amino acids. The mannose units were linked by 16 (main chain), as well as 12 and 13 (branched chain) bounds. Short oligosaccharides are bound to serine of the peptide chain by O-glycosidic linkages while polysaccharides are attached to asparagine of this peptide chain by N-glycosidic linkages, through the intermediate of N-acetylchitobiose. The mannan of the mutant strain is less branched but more phosphorylated.
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Methabocrinus erraticus Jaekel is described and the new family Methabocrinidae is proposed.  相似文献   

14.
华北辽东本溪寒武纪三叶虫Redlichia(Pteroredlichia)murakamii蜕壳标本完好地保存了头盖向下翻转的蜕壳状态,为寒武纪Redlichia的蜕壳模式提供了新的视角。此标本自由颊未保留,胸尾相连,头盖与胸部分离,头盖向下翻转,基本保持原位,为原地埋藏的蜕壳标本。蜕壳过程如下:面线裂开,头盖耸起卷曲并翻转,与胸部分离,胸部扭动,虫体摆脱老壳向前爬出。此蜕壳方式在McNamara(1986)报道的澳大利亚寒武纪Redlichia的蜕壳类型中并未出现。  相似文献   

15.
In a recent Perspective, Gerth et al. (2011) expressed concern over how Wolbachia (Wolbachia pipientis Hertig) infections may affect the success of DNA barcoding efforts in bees. The potential and realized effects of endosymbiont-induced selective sweeps on host mitochondrial DNA diversity have been noted repeatedly – and rightly so – in the literature for some years. However, we are equally concerned with other misconceptions, including (a) presuming that a positive Wolbachia test indicates a stable infection, (b) presuming that Wolbachia-infected hosts cannot be identified with a single-locus barcode, and (c) inferring specific Wolbachia–mtDNA interactions based only on incomplete genotyping of Wolbachia strains. We address these issues in the context of the Gerth et al. (2011) survey of Wolbachia prevalence among the German bee fauna. We also clarify some of the context-dependent strengths and limitations of DNA barcoding when it is used as a research tool by taxonomists and ecologists.  相似文献   

16.
An annotated checklist of bees (Hymenoptera: Apoidea: Anthophila) is compiled for Guadeloupe, an island located in the Lesser Antilles of the eastern Caribbean. The list has seventeen species, including three exotic species to the Caribbean, two apparently endemic of Guadeloupe, six species only known from the Caribbean and five species that occur both on the mainland and the Caribbean. The list is created using data from literature and from our own field researches, carried out between 2011 and 2013. A list of visited flowers, along with ecological notes for each species is also given.  相似文献   

17.
Ammonia and phosphate excretion by the Mediterranean euphausiid Meganyctiphanes norvegica (M. Sars) (mean individual dry weight, 60 mg) has been measured for one year. Experiments were conducted at 13°C on single, freshly caught animals maintained in unfiltered sea water. Possible influence of these experimental procedures upon values obtained are discussed. Phytoplankton re-uptake and bacterial activity proved insignificant, because of the short duration of the experiments (4–38 h). NH4 and PO4 excretion rates are higher shortly after collection and then decrease, reaching a steady level after 8 h for NH4, but continuously decreasing during the 38 h of the longer experiment in the c case of PO4. It is considered that earlier higher values are likely to be more representative of in situ rates despite possible ‘stress’ effects, because they are close to those of moderately fed animals kept in captivity; more stable values observed after 8–12 h are close to those of starved animals. Nevertheless, lower stabilized values are best used when investigating seasonal variations. Excretion rates are low (0.07 to 0.11 μg-at.NH4-N.mg?1.day?1, and 0.009 to 0.010 μ-at.PO4-P mg?1.day?1) in summer, autumn and early winter. They rise sharply from January–February (0.12 μg-at.NH4-N.mg?1.day?1 and 0.015 μg-at.PO4-P.mg?.day?1) to peak spring values (0.25 μg-at.NH4-N.mg?1.day?1 and 0.026 μg-at. PO4-P.mg?1.day?1). The significance of inorganic excretion with regard to total (inorganic + organic) excretion is discussed. The nitrogen and phosphorus content of the animals were simultaneously measured and amount, respectively, to 9.5 and 0.8% of body dry weight (mean yearly value). Based on inorganic excretion only, the mean values of turnover are 66 days for nitrogen (61–92 days from May to February, 28–32 days in March–April) and 16 days for phosphorus (12–22 days with limited seasonal variation). Mean N/P ratio by atoms for excretion amounts to 9.1 after 8–12 h (it increases afterwards due to continual decrease in PO4 excretion) but there are significant seasonal variations. The mean N/P ratio by atoms for the animals is 27.4; it is lower (22.4) between March and August, and higher (29.2) from September to February. With a view to investigating the change in the N/P ratio in the chain prey → predator → excretion, which allows calculation of growth efficiency factor (k2) and hence secondary production, the nitrogen and phosphorus of the stomach contents of the animals were measured. Due to unknown bias (possibly a terrestrial origin of food particles, or loss of phosphorus during conservation of samples), the results were disappointing (N/P by atoms = 69, instead of a value necessarily ranging between 9.1 and 27.4), and did not allow calculation of k2.  相似文献   

18.
Recruitment is a key process for forest sustainability, especially in warm margin of distribution area. The influence of climate (temperate or warm), of soil water availability, and of allelopathic interactions from different forest species have been tested on the germination of Fagus sylvatica in controlled climatic conditions. Germination rates of non-dormant Fagus seeds were improved by relatively warm temperatures (20 °C), but reversibly stopped under heat constraint (27 °C). The relative growth rate of Fagus seedlings was better under temperate climatic conditions. Foliar extracts of Hedera helix showed the highest allelopathic effect on Fagus recruitment, especially in temperate conditions. Our results suggest a limitation of Fagus recruitment in warm margin of its distribution area, and a modulation of recruitment success according to the identity of plant neighbourhood.  相似文献   

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Résumé Chez les deux Columbidae étudiés, les cellules C sont présentes à la fois dans les corps ultimobranchiaux et dans la thyroïde. Les corps ultimobranchiaux sont constitués de cordons renfermant des cellules glandulaires et des cellules bordantes. Dans certaines zones périphériques de la thyroïde, des cordons ultimobranchiaux typiques sont localisés dans les espaces interfolliculaires et sous-capsulaires. Des cellules C folliculaires basales analogues à celles de la thyroïde du mammifère sont rarement observées.Les caractères morphologiques des cellules C sont identiques quelle que soit leur localisation: ultimobranchiale, thyroidienne extrafolliculaire ou folliculaire basale. Les granules sécrétoires diffèrent légèrement par leur forme chez le pigeon et le tourtereau; leur diamètre moyen est plus variable d'une cellule à l'autre chez le pigeon.Des contacts neuroglandulaires existent au niveau des cordons glandulaires localisés dans les corps ultimobranchiaux et dans la thyroïde. Leur signification reste obscure.
Ultimobranchial and thyroidian localization of C cells in two Columbidae: the pigeon and the turtle-doveAn electron microscopic study
Summary In the two Columbidae we studied, C cells are present both in the ultimobranchial bodies and in the thyroid. Ultimobranchial bodies consist of cords which are made up of glandular cells and limiting cells. In certain peripheral regions of the thyroid, typical ultimobranchial cords are situated in the interiollicular and infracapsular spaces. Basal follicular C cells similar to those of the mammalian thyroid are rarely observed.The morphological characteristics of the C cells are identical whatever their situation may be: ultimobranchial or thyroidian, be it extrafollicular or basal follicular. The secretory granules differ slightly by their shape in the pigeon and the turtle-dove; their medium diameter varies more from one cell to another in the pigeon.Neuroglandular contacts exist at the level of the glandular cords situated in the ultimobranchial body and in the thyroid. Their signification is not clearly understood.
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20.
描述了始新世基辅鸟类新标本。研究表明基辅鸟类生活在特提斯海中始新世早路特期至早巴顿期,分布范围至少包括乌克兰东部的伊克夫到中部的基辅地区。暂时将基辅鸟归人鹱形目。虽然基辅鸟具有一些鹱形目的典型特征,但缺少鹱形目的衍生特征,或许代表了近祖状态。  相似文献   

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