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1.
2.
Jane J. Turner James G. Herndon Maria-Carmen Ruiz de Elvira Delwood C. Collins 《Primates; journal of primatology》1989,30(4):523-529
Endogenous testosterone levels were measured in association with sexual, aggressive, and social/affiliative behaviors in 11
outdoor-housed female rhesus monkeys over a ten-month period. Several behaviors (sex directed toward the male, sex received
from the male, aggression directed toward the male, submission directed toward the male, submission directed toward the female,
and groom another female) were significantly (p<0.05) positively correlated with testosterone in from one to five females. No trends were strong enough across all females
to suggest that any of these correlations have species-wide significance. Factor analysis revealed clearcut clusters of behaviors,
but elevations in testosterone were not strongly associated with any of these clusters. It is concluded that endogenous testosterone
levels have little measurable effect on overt behavior in female rhesus monkeys. 相似文献
3.
This study reports the first demonstration within a single insect genus (Tribolium) of both the acute, or lethal-midlethal, dose-independent pattern of mortality, and the hyperacute, dose-dependent pattern, after appropriate doses of ionizing radiation. This demonstration provides resolution of apparently contradictory reports of insect responses in terms of doses required to cause lethality and those based on survival time as a function of dose. A dose-dependent mortality pattern was elicited in adult Tribolium receiving high doses, viz., 300 Gy or greater; its time-course was complete in 10 days, before the dose-independent mortality began. Visual observations of heavily-irradiated Tribolium suggested neural and/or neuromuscular damage, as had been previously proposed by others for lethally-irradiated wasps, flies, and mosquitoes. Results of experiments using fractionated high doses supported the suggestion that the hyperacute or high-dose mode of death is the result of damage to nonproliferative tissues. Relative resistance of a strain to the hyperacute or high-dose mode of death is not necessarily correlated with resistance to the midlethal mode, which is believed to be the result of damage to the proliferative cells of the midgut.
Résumé Les résultats de nombreuses études des réactions des insectes adultes de différents groupes à l'irradiation s'opposent quant à l'importance de la dose provoquant la létalité et quant aux modalités de la mort. Les diptères et les guèpes impliquent des doses très élevées,-des centaines de Gy-, ne présentent aucune période caractérisant la mort par irradiation, et décèdent de plus en plus tôt avec l'augmentation des doses. Beaucoup d'autres insectes succombent à des doses (milétalelétale) beaucoup plus faibles,-de quelques Gy à des dizaines-, et quelle que soit la dose meurent au bout d'un temps voisin.Au cours de cette étude, nous avons pu observer que ces deux types de mortalité peuvent être provoqués chez le même genre d'insecte (Tribolium), avec des doses convenables d'irradiation . Un syndrôme caractéristique a été provoqué avec des doses très élevées, de 300 Gy ou plus,-à ces doses la mort est obtenue en 10 jours après l'irradiation. L'absence de syndrôme caractéristique se produit avec des doses inférieures ou égales à 80 Gy; la mort a lieu alors entre 10 et 16 jours en fonction de la dose.Les différences entre les deux types de décès indiquent deux processus de mort par irradiation. La manifestation d'une désorientation et d'une perte de coordination motrice chez les Tribolium fortement irradiés suggère des altérations neurales et/ou neuromusculaires comme cause/s de ce type de mort provoquée par des doses élevées. L'implication de tissus sans prolifération a été confortée par les résultats d'expériences utilisant de hautes doses fractionnées. Le type de mort milétal est considéré après de nombreuses observations indépendantes, comme le résultat d'atteintes à la prolifération des cellules de l'intestin moyen.Les données contradictoires sur les réactions des insectes aux irradiations proviennent d'abord de l'absence de connaissances sur le lieu des dégâts. Les diptères sont connus maintenant, après différentes études, comme perdant complètement l'aptitude au renouvellement cellulaire, et présentent ainsi un type de mort avec dose élevée. Beaucoup d'autres insectes adultes ont un renouvellement cellulaire de l'intestin moyen limité, et ainsi présentent le type de mort milétal. Le type de mort, dit haute dose, peut être induit dans cette dernière catégorie d'insectes par une irradiation suffisamment forte, et, dans le cas du Tribolium le déroulement de la mort se produit alors de deux façons bien distinctes.相似文献
5.
Summary Female gametangia of the normal bisexual Allomyces species are richer in fluorescently probed (FITC) actin, independent of their apical or subapical positioning during differentiation on the fertile hyphae. The anti-actin, cytochalasin D, can selectively suppress male differentiation in both species. 相似文献
6.
Dramatic founder effects in Amerindian mitochondrial DNAs 总被引:33,自引:0,他引:33
Southwestern American Indian (Amerindian) mitochondrial DNAs (mtDNAs) were analyzed with restriction endonucleases and found to contain Asian restriction fragment length polymorphisms (RFLPs) but at frequencies very different from those found in Asia. One rare Asian HincII RFLP was found in 40% of the Amerindians. Several mtDNAs were discovered which have not yet been observed on other continents and different tribes were found to have distinctive mtDNAs. Since the mtDNA is inherited exclusively through the maternal lineage, these results suggest that Amerindian tribes were founded by small numbers of female lineages and that new mutations have been fixed in these lineages since their separation from Asia. 相似文献
7.
A stranger mother-son pair of the chimpanzee was observed twice interacting with conspecifics of a neighbouring unit-group:
first, when the mother and son accidentally encountered them within the core area of the former; second, when the mother and
son temporarily immigrated for about one week. On both occasions, the mother and son were severely attacked by adult males
of the neighbouring unit-group, and would have been killed had it not been for human intervention. The main target of the
aggression was not the infant, but the mother. Some adult males intervened and prevented other males and females from attacking
the mother-son pair. Moreover, most adult males displayed an ambivalent attitude since they showed aggression towards them
on one occasion, but groomed, reassured and played on another. The reasons for the variable responses of adult males to a
stranger female are discussed in terms of possible differences in their mating strategies. 相似文献
8.
9.
To evaluate whether the median eminence (ME) is a site of action of CRF (corticotropin releasing factor) on GH secretion and
to determine the possible role of estradiol and progesterone in modifying theses secretion, we injected CRF (0.25, 0.75, 1,
and 1.5 nmol of peptide dissolved in 1 μl of water) directly into the ME in three experimental groups of rats: Long-term ovariectomized
(OVX); OVX primed by estradiol (OVX±E) and OVX primed by estradiol plus progesterone (OVX±EP). Blood was collected to determine
GH (30, 60, 90, and 120 min postinjection) Serum T3, T4, and glucose levels were measured in OVX±E rats 30 min postinjection. CRF at all doses studied significantly decreased serum
GH levels in the three experimental groups. Serum T3, T4, and glucose levels were unchanged after CRF administration. The results suggest that: CRF inhibits “per se” GH secretion,
at least in part, by a central action in the ME. The inhibitory effect of CRF on GH is independent of the estrogen/progesterone
status of the animal. CRF at ME levels may participate in a variety of stress-related responses, including growth inhibition,
through GH suppression. 相似文献
10.
东方次睾吸虫电镜研究(吸虫纲:后睾科)V.雌性生殖器官 总被引:1,自引:0,他引:1
东方次睾吸虫雌性生殖器官(卵巢、输卵管、卵黄-输卵管、卵模、梅氏腺和子宫)透射电镜 观察。卵巢内有不同成熟期的生殖细胞,成熟初级卵母细胞有几个靠近核的核仁样小聚体和许多沿 质膜的皮质颗粒。首次发现并描述卵巢和输卵管接合处(卵巢壶腹)的超微结构。输卵管上皮为纤 毛状。梅氏腺仅一种类型膜状小体细胞,经有微管支持的细小管道穿过卵模将膜状小体排入卵模腔 内。在卵黄-输卵管和卵模中有精子,卵模和子宫中有受精卵、虫卵(扫描电镜):大小 26. 05× 11.46-13.55μm,卵盖直径6.26-6. 89μp,卵壳表面布满膜状隆起。文中对卵巢和梅氏腺的超微 结构特点进行了讨论。 相似文献