共查询到20条相似文献,搜索用时 15 毫秒
1.
Jean Pierre Aguilar 《Geobios》1977,10(4):643-645
Discovery of fossil rodents of oligocene and lower miocene age (Aquitanian) in the Narbonne — Sigean basin, and of pliocene age at the Leucate plateau and cliff. 相似文献
2.
Ecdysteroid titer in whole extracts of female O. gammarellus varies during the course of the moult cycle: it is minimal at the beginning of the intermoult cycle (stages A, B and Ca) and in D0, and maximal in D2. In hemolymph, the hormone content presents a single peak level in D2; this peak is constituted by ecdysterone, as revealed by HPLC. Ovaries, at the end of vitellogenesis, contain ecdysterone and low polarity substances. Ecdysteroids are also present in eggs after laying. Variations in ecdysteroid levels seem to influence oocyte growth; vitellogenin synthesis, however, is independent of hormonal fluctuations. 相似文献
3.
Jean-Pierre Chanut 《Journal of experimental marine biology and ecology》1975,17(3):239-259
Seven spatial dispersions of organisms, reflecting some constraints of various physical and biological factors of the pelagic environment were simulated on computer. The relationships between the sampling methods (tow length, net size), the pelagic population dispersion patterns, and the sampling error were investigated by computer simulation. Two categories of dispersions were identified: 1) random or relatively uniform dispersions of organisms (including Poisson, gradient, and negative contagous dispersions), characterized by an index of dispersion ; and 2) overdispersed distributions of swarming or clustering organisms (including positive contagion and centric aggregation dispersions), characterized by a value of .The origin and size of the sampling errors as deduced from the analysis of variance change, considerably from one group of dispersions to the other. In the first case, the net size was dominant, whereas in the second case the tow length and patch size effects are more critical. In general, the precision of estimations decreases as the over-dispersion of organisms increases. The confidence limits, for a simple estimation of abundance, vary considerably with the spatial dispersion, ranging from narrow values for the relatively uniform dispersions to very large values for the overdispersed distributions. There is an increasing imprecision in the estimate of population abundance as the dispersion coefficient increases.Analysis of coefficients of variation indicates that more precise estimates of abundance may be obtained if a practical sampling procedure is applied to a group of specific organisms. Furthermore, it is suggested that a simulated approach, performed prior to ocean sampling, permits the establishment of the optimal sampling procedure for the species under study. 相似文献
4.
Summary During the period between apolysis and ecdysis, the vesicular glands show many important transformations which affect not only the cuticular ductules, but all the cells. The cytoplasm of the glandular cells undergoes a partial autolysis, whereas other parts of the cells present a high secretory activity. Immediately after the apolysis the cellular reservoir empties and disappears almost completely; soon after, refills with secretion. The most interesting transformations concern each ciliary cell, always associated with a glandular cell. In the first phase of the moulting cycle, the dendrite of the ciliary cell grows a ciliumlike extension (= distal region of the dendrite), which penetrates into the corresponding ductule; the new intima of this ductule is laid around the cilium. At the same time, the proximal region of the dendrite forms a circular fold around the base of the cilium and begins to secrete a material which will form the end apparatus. This latter is finished during the second phase of the cycle. The third phase is characterized by the degeneration of the distal region of the dendrite and the circular fold. Thus, the end apparatus is not a secretion of the ductule-carrying cell, but of the ciliary cell. At the end of the moulting period, just before ecdysis, the vesicular gland again takes the structure characteristic of the intermoult: the reservoir of the glandular cell is very large; the cuticular apparatus is almost formed; the dendrite of the ciliary cells shows, at its apex, a short cilium (= ciliary region s. str. + short distal region) surrounded by microvilli, free in the secretion of the reservoir. 相似文献
5.
Résumé Les auteurs distinguent 8 types cellulaires dans l'EpongeOphlitaspongia seriata (Grant) en réorganisation après dissociation. Ils décrivent leur comportement au cours de la réorganisation, leur ultrastructure et leurs capacités de différenciation.Les cellules globifères sont particulièrement remarquables par leurs nombreuses inclusions cytoplasmiques tubulaires de 70 m. 相似文献
6.
7.
L. Fenaux G. Malara C. Cellario R. Charra I. Palazzoli 《Journal of experimental marine biology and ecology》1977,28(1):17-30
The importance of the different compartments of the body in Arbacia lixula (L.) has been investigated by means of short duration starvation experiments carried out during periods of sexual rest and of maturity. The oxygen consumption was also determined during those two phases of the sexual cycle. The amount of calories furnished by the transformation of the biochemical constituents where significant lowering of the levels has been noted, cover largely the needs of standard metabolism.Annual variations of the protein, lipid and carbohydrate percentage in the 3 compartments: test, gut, gonads, have been followed from September 1973 to May 1974. An increase in the proteins is observed in the gonads from the beginning of growth to maturity, as well as an increase in the carbohydrates and the lipids during the period of growth. The carbohydrates of the gut increase in winter and the lipids in spring.An estimate has been made of the quantity of energy liberated by the 3 compartments on the death of the sea urchin. 相似文献
8.
Résumé L'étude de la dynamique des populations de la cochenille farineuse des arbres fruitiersRastrococcus invadens Williams [Hom.: Pseudococcidae], avant et après l'introduction accidentelle du parasito?de primaire indo-pakistanaisGyranuso?dea tebygi Noyes [Hym.: Encyrtidae], a été entreprise au Congo, sur 2 de ses plantes h?tes, le manguier (Mangifera indica L.,Anacardiaceae) et le frangipanier (Plumeria alba L.,Apocynaceae).
Avant l'introduction du parasito?de exotique, le complexe entomophage local s'est révélé peu abondant et diversifié. Le profil
de gradation des populations du ravageur, très différent sur les 2 plantes h?tes, semble davantage lié aux caractéristiques
physiologiques et phénologiques du végétal qu'aux facteurs climatiques. La cochenille est capable de développer 5 générations
de 70–80 jours par an sur les 2 plantes h?tes.
Trois à quatre mois après son introduction, les 50 à 90% de parasitisme développés parG. tebygi ont affecté significativement la dynamique des populations de la cochenille. Huit à neuf mois plus tard, son maintien sur
de faibles effectifs du ravageur confirme son acclimatation. Les 50 à 60% de mortalité provoqués par les 8 espèces du complexe
hyperparasitaire ne paraissent pas limiter son efficacité.
Le complexe parasitaire deR. invadens est comparé à celui de la cochenille du manioc.
相似文献
9.
10.
Augusta Amargier S. Abol-Ela S. Vergara G. Meynadier D. Martouret G. Croizier 《BioControl》1981,26(3):319-332
Résumé Une polyédrose nucléaire de la tordeuse de la pelure,Pandemis heparana
Denis & Schiffermuller (Lep.: Tortricidae) due à un baculovirus isolé dans un verger de pommiers en France est étudiée. Le baculovirus, uniquement actif sur les larves
nouvelles nées, induit un arrêt de développement des larves au stade L3 et une mortalité ultérieue des larves aux stades L5
et L6. L'étude en microscopie optique et en microscopie électronique des larves L5 et L6 présentant des sympt?mes très prononcés
de la viroise (début de paralysie et couleur blanchatre des segments abdominaux) montre que c'est essentiellement le tissu
adipeux et accessoirement certains hémocytes et quelques cellules de l'hypoderme qui sont le siège de la multiplication virale.
La morphogénèse virale dans les cellules du tissu adipeux est décrite en détail. Certains aspects de l'étude ultrastructurale
liés à la forme en massue des virions, au processus de cristallisation des polyèdres et à l'accumulation de masses fibrillaires
viro-induites sont discutés.
Summary A nuclear polyhedrosis virus infecting the torticidPandemis heparana Denis & Schiffermuller, collected in an apple-orchard in France was isolated and studied. The baculovirus is active only in the newly hatched larvae. It induces a delayed arrest of development in the L3 larvae and subsequently the death of L5 and L6 larvae. Study by light and electron microscopy of L5 and L6 larvae exhibiting very marked symptoms of the virus disease (early stages of paralysis and whitish colour of abdominal segments) shows that the site of multiplication of the virus is mainly located in the fat body cells and occasionally in some hemocytes or hypoderm cells. Virus morphogenesis within the fat body cells is described in detail. Some aspects of the ultrastructure such as clubbed virions, process of crystallization of polyhedral bodies and clumps of fibrous material induced by the virus, are discussed.相似文献
11.
Henri Cappetta 《Geobios》1981,14(5):563-575
Recent researches in the phosphat-bearing basins ofMorocco have allowed to collect new selachian forms. In this paper, three Ypresian genera from Ouled Abdoun basin, new for Morocco, are described: Heptranchias howellii (Reed, 1946), Alopias denticulatus nov. sp. and Odontorhytis pappenheimiBöhm, 1926. The re-discovery of the genus Odontorhytis allows to state precisely its morphological dental features and to affirm that it is well a selachian and not a teleostean, as it was thought. The stratigraphic distribution of some species is stated precisely. 相似文献
12.
Cryopreservation of ejaculated bovine spermatozoa induces severe cell death. In a preliminary study, we observed that cryopreservation and/or thawing was also associated with early apoptotic features in living spermatozoa: i) decrease of the mitochondrial membrane potentialαψm), ii) caspase activation, iii) increase of membrane permeability, without the appearance of late characteristics: iv) no DNA fragmentation. This process has been called “apoptosis-like”. In this study, we evaluated the consequences of each step of cryopreservation of bovine spermatozoa: dilution in cryopreservation medium, equilibration and cryopreservation in liquid nitrogen/thawing. Apoptosis and acrosomal reaction were analysed by flow cytometry and the presence of AIF (Apoptosis Inducing Factor) was analysed by western blot. We observed that dilution in cryopreservation medium induced a marked and immediate increase of the proportion of living spermatozoa with a lowΔψm. After equilibration, the proportion of living spermatozoa with active caspases then began to increase. After the complete cryopreservation/thawing process, this population reached a maximum, and a significant increase of membrane permeability was observed. These results, showing that some features of the “apoptosis-like” phenomenon are initiated in the early steps of cryopreservation, suggest that ice formation may not be the only factor affecting spermatozoa. The consequence of thisΔψm decrease could be the release and/or activation of various pro-apoptotic factors in the cytoplasm. Presence of the pro-apoptotic AIF factor in bovine spermatozoa suggests a possible role of this protein during the cryopreservation process. We also confirmed that cryopreservation of bovine spermatozoa induced an acrosomal reaction. It would be of interest to investigate the relationship between this acrosomal reaction and membrane permeability. A better understanding of the cellular mechanisms involved in sperm cryopreservation would help to improve the preservation of bovine sperm. 相似文献
13.
N. Ismaili Alaoui E. Hindie A. Sergent Alaoui S. Fakir S. Mouzoune C. De Labriolle Vaylet 《Médecine Nucléaire》2012,36(9):479-485
IntroductionIncidence of congenital hypothyroidism (CH) is about one in 3000 newborn and CH is the main cause of avoidable mental retardation and abnormality of growth. It may be permanent or transient. Thyroid scintigraphy allows in most of cases to specify the type of CH. The aim of this study was to clarify the contribution of scintigraphy for the diagnosis, management and prognosis of the children with CH, on basis the experience from the Nuclear Medicine department of Armand-Trousseau Children Hospital.Patients and methodsWe retrospectively reviewed all the children (0–3 months) referred between January 2005 and December 2008 to the pediatric hospitals in Paris for the management of neonatal hypothyroidism. A planar scintigraphic acquisition, including stomach and bladder, was done 1 h after intravenous injection of 1.1 MBq of 123I. When the thyroid was normally located, a perchlorate discharge test was performed.ResultsDuring the study period, 181 infants had thyroid scintigraphy for CH. The sex-ratio girl/boy was 1.7. Fifty-six percent had thyroid dysgenesis (21% agenesis, 35% ectopia). Seventy-nine patients (44%) had an eutopic thyroid. A significant association was observed between TSH levels and etiology of HC, and between TSH levels and the percentage of iodine uptake decrease after the perchlorate discharge test: the highest level of TSH was observed in the case of athyreosis and when perchlorate test was very disturbed (fall of thyroid activity greater than 70%).ConclusionThyroid scintigraphy in association with ultrasound permits a precise characterization of the etiology of CH. These examinations help clinicians to ensure an optimal management of patients by identifying those with most severe hypothyroidism, and to inform parents most completely on duration of treatment and existence of a potential risk during a future pregnancy. 相似文献
14.
Marcel Weyant 《Geobios》1975,8(6):361-408
On south western Ellesmere Island, near the head of Eids Fiord, the Eids Formation and thelower member of the Blue Fiord Formation, to which an Emsian age may be assigned on conodont evidence, yield large and diversified ostracode faunas. Over ninety species and subspecies are distinguished, including the fauna described by I. P. Tolmachoff (1926) from the «Series Db in the Goose Fiord area near the southern shore of the island. The present report, the first one of a series of four, deals with the families Beyrichiidae, Hollinidae, Pribylitidae, Rozhdestvenskayitidae and Youngiellidae. Twenty eight taxa, among them three new genera, eleven new species and one new subspecies, are described. 相似文献
15.
Alain Beyneix 《L'Anthropologie》2012,116(2):222-233
This paper proposes to define the main characteristics of the burials and the evolution of funeral behaviours during the Neolithic times, between about 5500 and 2300/2200 B.C., in the present territory of Aquitaine. For the moment, no burial was found for early Neolithic. During the middle Neolithic, about 4500 B.C., appear the first megalithic graves, passage graves (Angoumoisin type) and barrow cists, as well as burial caves. Late Neolithic, between 3700 and 2300/2200 B.C. is the great period of megalithic graves. Single quadrangular dolmen (Caussenard type) were built in Dordogne and in the Entre-deux-Mers in Gironde, gallery graves, the “allées d’Aquitaine” as to the “allées girondines” extended in the centre of the Aquitaine country while in the western Pyrénées the single quadrangular dolmen increased. In return, caves and rock shelter were, it seems to me, less prized by the people during the end of Neolithic times to leave the dead. 相似文献
16.
Danielle Decrouez 《Geobios》1976,9(4):515-519
A new benthonic Foraminifera: Pseudolituonella? guerneti n. sp. (Ataxophragmiidae) has been found in upper cenomanian limestones of central Eubee (Greece, pelagonian zone). It is described and illustrated in this publication. 相似文献
17.
Claude Guérin 《Geobios》1982,15(4):593-598
For the Uppermost Miocene the already known zones MN 9 to MN 13 are used without any change; they prove to be particularly useful for the study of fossil rhinocerotids. The Plio-Villafranchian age corresponds to the zones 14 to 19, the definition of the first five being completed and the last being new. Middle to Upper Pleistocene age deals with the zones 20 to 26, all being new and defined following the same principles. 相似文献
18.
Glucose derivatives of hydroxycinnamic acids have been identified in tomato fruits either as esters or glucosides, the latter always being the most abundant and increasing during growth and at the time of ripening. These compounds can be synthesized in vitro by a fruit glucosyltransferase from free hydroxycinnamic acids and UDPG; glucosides are always formed in higher amounts than esters. 相似文献
19.
Jacqueline Vaquette Jean-Louis Pousset René-Raymond Paris André Cavé 《Phytochemistry》1974,13(7):1257-1259
Four alkaloids have been isolated from the stem bark of Zatithoxylum decaryi. Three are known, dictamnine skimmianine, 4-methoxy-1- methyl-2-quinolone. The fourth decarine is new; its structure has been established as 9-methoxy-10-hydroxy-2,3-methylenedioxybenzophenanthridine.1 相似文献
20.
S. El Issami M.A. Bsiss A. Matrane S. Hiroual S. Bennani Doubli N. Ben Raïs Aouad 《Médecine Nucléaire》2013,37(10-11):520-525
The presence of a parathyroid gland in ectopic position constitutes one of the leading causes of surgery failure. For this purpose, scintigraphy takes a major place in the anatomical localization of pathological parathyroid and so facilitates its treatment. The advent of hybrid cameras combining single photon emission tomography to CT (SPECT/CT) has further strengthened the contribution of this imaging modality in the precise localization of ectopic parathyroid and its anatomical relationships. The objective of our work is to illustrate the interest of hybrid imaging SPECT/CT, compared to planar scintigraphy and ultrasounds within the framework of primary hyperparathyroidism, particularly ectopic situation through three cases. 相似文献