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1.
D. Tab Rasmussen 《International journal of primatology》1985,6(5):501-517
Breeding records of 11 taxa of captive lemurs housed at the Duke University Primate Center (DUPC), North Carolina, were analyzed
for differences in the timing of births, for the relationship between breeding season and photoperiod, and for differences
in litter size. At DUPC there are significant differences in the timing of births among certain taxa, including differences
among some subspecies of Lemur fulvus.However, changes in latitude result in changes in the timing of the breeding season. Lemurs moved to higher latitudes mate
at lower light-dark ratios than on Madagascar. The data presented here are consistent with the following model: a photoperiodic
cue initiating reproductive activity, presumably a light-dark threshold, precedes the actual mating season by approximately
2 months, with an intervening period of physiological and social preparation. On Madagascar, selection may have favored births
that coincide with the end of dry seasons and the beginning of wet seasons, which results in lactation and weaning during
times of resource abundance. Taxa from the north and east have the highest mean litter sizes; those from the west have the
lowest. 相似文献
2.
Lucas Henriques Viscardi Danilo Oliveira Imparato Maria Ctira Bortolini Rodrigo Juliani Siqueira Dalmolin 《Molecular biology and evolution》2021,38(3):735
The origin of nervous systems is a main theme in biology and its mechanisms are largely underlied by synaptic neurotransmission. One problem to explain synapse establishment is that synaptic orthologs are present in multiple aneural organisms. We questioned how the interactions among these elements evolved and to what extent it relates to our understanding of the nervous systems complexity. We identified the human neurotransmission gene network based on genes present in GABAergic, glutamatergic, serotonergic, dopaminergic, and cholinergic systems. The network comprises 321 human genes, 83 of which act exclusively in the nervous system. We reconstructed the evolutionary scenario of synapse emergence by looking for synaptic orthologs in 476 eukaryotes. The Human–Cnidaria common ancestor displayed a massive emergence of neuroexclusive genes, mainly ionotropic receptors, which might have been crucial to the evolution of synapses. Very few synaptic genes had their origin after the Human–Cnidaria common ancestor. We also identified a higher abundance of synaptic proteins in vertebrates, which suggests an increase in the synaptic network complexity of those organisms. 相似文献
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Spencer G. Lucas Bolat U. Bayshashov Lyubov A. Tyutkova Ayzhan K. Zhamangara Bolat Z. Aubekerov 《Pal?ontologische Zeitschrift》1997,71(3-4):305-314
At Aktau Mountain in the Ili depression of eastern Kazakstan, fossil mammals that encompass the Paleogene-Neogene boundary occur at three stratigraphic levels. The lowest level is in the lower Kyzylbulak Formation and produces Brontotheriidae and the hyracodontidArdynia and is tentatively assigned a late Eocene (Ergilian) age. The lower part of the overlying Aktau Formation produces fossils of the giant rhinocerosParaceratherium and is tentatively assigned a late Oligocene (Tabenbulukian) age. The upper part of the Aktau Formation yields a fossil mammal assemblage that includesGomphotherium,Stephanocemas, Brachypotherium andLagomeryx. It is clearly of Miocene age, probably late early Miocene (late Burdigalian), a correlative of European Reference Level MN 5 and the late Shanwangian of China. The Paleogene-Neogene boundary at Aktau Mountain thus is in the Aktau Formation. 相似文献
5.
Jeff A Johnson Heather RL Lerner Pamela C Rasmussen David P Mindell 《BMC evolutionary biology》2006,6(1):65-12
Background
Populations of the Oriental White-backed Vulture (Gyps bengalensis) have declined by over 95% within the past decade. This decline is largely due to incidental consumption of the non-steroidal anti-inflammatory veterinary pharmaceutical diclofenac, commonly used to treat domestic livestock. The conservation status of other Gyps vultures in southern Asia is also of immediate concern, given the lack of knowledge regarding status of their populations and the continuing existence of taxonomic uncertainties. In this study, we assess phylogenetic relationships for all recognized species and the majority of subspecies within the genus Gyps. The continuing veterinary use of diclofenac is an unknown but potential risk to related species with similar feeding habits to Gyps bengalensis. Therefore, an accurate assessment of the phylogenetic relationships among Gyps vultures should aid in their conservation by clarifying taxonomic uncertainties, and enabling inference of their respective relatedness to susceptible G. bengalensis. 相似文献6.
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Alba Luengo Zhaoqi Li Dan Y. Gui Lucas B. Sullivan Maria Zagorulya Brian T. Do Raphael Ferreira Adi Naamati Ahmed Ali Caroline A. Lewis Craig J. Thomas Stefani Spranger Nicholas J. Matheson Matthew G. Vander Heiden 《Molecular cell》2021,81(4):691-707.e6
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9.
In vitro and in vivo models to study the pathogenesis of thyroid autoimmunity are reviewed. Animal models with experimentally induced or spontaneously developed autoimmune thyroid disease as well as transplantation models have been used extensively in these studies, but also the use of thyroid cell cultures from both humans and animals has contributed to the present state of knowledge. Cytokines may play a role in the pathogenic mechanism in thyroid autoimmunity. The major in vitro and in vivo effects of for example interleukin-1, tumour necrosis factor and gamma-interferon on differentiated thyroid cell functions are inhibitory. The advantage of using cell cultures has been the possibility of studying an influence on thyrocytes from a single agent individually, such as cytokines, hormones or growth factors. The disadvantage is that an organism is under the influence of a multitude of factors that can only be investigated in vivo in intact organisms. Both types of models have therefore been important in the understanding of thyroid autoimmunity. 相似文献
10.