The growth and development of the American Society of Zoologists(ASZ) came in an era of rapid expansion among the life sciences,as well as during a period when biologists were seeking to providethemselves with a united and effective voice. In ASZ's earlyyears it usually remained subsidiary, overshadowed by largerorganizations like the American Society of Naturalists or theAmerican Association for the Advancement of Science, and constrainedby its small enrollment to hold meetings in conjunction withthese larger societies. As ASZ's numbers increased, however,new members entered from many specialized fields, and it becamea focal organization for associations dedicated to such studiesas ecology, genetics, animal behavior, or systematic zoology.Much of ASZ's success in achieving its integrative status canbe attributed to the formation of divisions within the Society,each dedicating itself to the specialized interests of its ownmembers under the larger umbrella of zoology. This development,of course, paralleled the interaction between ASZ and the largersocial issues that have arisen during the century of the Society'shistory. ASZ has consistently concerned itself with just treatmentfor all, regardless of race or sex; with government supportof science; with the education of science teachers and of youngand talented biologists; and with all those issues that improvethe productivity of zoologists and enhance their capacity forreaching an ever deeper understanding of animal biology. 相似文献
The abundance and great diversity of life on coral reef ecosystemsprovides many good opportunities for studying the evolutionand specializations of neurophysiological systems and behavior.Crucial stages in the evolution of nervous systems appear tohave occurred in the Precambrian, as revealed in Ediacaran fossilsand their closest living relatives. By the Ordovician, whenChazy "reefs exemplify some of the earliest complex animalcommunities fixed in one place, more elaborate neurologicalmechanisms for orientation, predation, and escape reactionsare indicated. With the evolution offish, the behavioral richnessof reef communities became further enhanced. Elaborate specializationsof feeding, defensive, aggressive, signaling, schooling, andreproductive behaviors are common in fish. Several examplesof behavioral studies on reef organisms are used to illustrateresearch methodologies and the types of conclusions which maybe drawn. These examples include: (1) analysis of symbioticbehavior of an invertebrate and a vertebratesea anemoneand clownfish; (2) signaling behavior of a fishthe sailfishblenny; and (3) a combined electrophysiological and behavioralanalysis of orientation and feeding/attack behaviorsharks.An almost endless number of possibilities for similar analysismakes the organisms of coral reefs especially useful, and challenging,for teaching purposes as well as further research. 相似文献
Embryonic axes of Phaseolus vulgaris undergo a transition fromdesiccation-intolerance to desiccation-tolerance in the courseof their development. Biochemical and ultrastructural observationsindicate that desiccation and rehydration during the early intolerantdevelopmental stages drastically reduces the metabolic and cellularintegrity of the axis. During the desiccation-tolerant stagesuch perturbations do not occur. Coincident with the acquisitionof desiccation-tolerance during development the seeds gain thecapacity to germinate upon subsequent rehydration. Drying presumablyacts to terminate developmental processes and to initiate themetabolic processes essential for the completion of germination.During germination of the mature axis, desiccation and rehydration,up to 12 h from the start of imbibition, does not affect subsequentseedling growth and development. But gradually desiccation-tolerancedecreases and metabolism is severely and irreversibly reducedby drying. 相似文献
The morphology of the middle ear region including die basicranium and quadrate of Strulhxo is very simil.n to ilic same region in the orders Procellariiformes, Pelecaniformes, Ciconiiformes and Sphenisciformes. Struthio though, has some unique middle ear characters such as die lack of a chorda tympani nerve, the arrangement of die glossopharyngeal and vagus nerve foramina, die structure in the upper neck of die external ophthalmic vein and die position of die Eustachian tube. The articulatory surfaces for the quadrate bom on die zygomatic process of the squamosal and the mandible are unique in Struthio when compared to the several orders mentioned above. 相似文献
WHEN inbred mice are grafted with skin from inbred donors that differ from the recipients only by a single minor histocompatibility antigen, it is commonly observed that some recipients will retain their skin grafts while others will reject them. This is true of incompatibility for H-Y antigen, which is responsible for the rejection of male grafts by otherwise histocompatible inbred females of the same inbred strain1. Thus in the DBA/2 (DBA) strain, male-to-female skin grafts are rejected by only some recipients; in the C57BL (B6) strain, females always reject male skin; and C3H/An (C3H) females usually accept male skin grafts indefinitely. 相似文献
MOST investigators concerned with interferon synthesis in vivo have used the experimental procedure described by Baron and Buckler1, in which circulating interferon is induced by intravenous administration of viruses. When interpreting results, however, it is difficult to know which cells are responsible for circulating interferon synthesis in the animal. Using a radiobiological approach, we have shown that after an intravenous injection of virus, interferon released into the blood stream of mice originates in cell populations of varying radiosensitivities, depending on the virus inoculated2. Myxo-virus-induced circulating interferon production is characterized by high radiosensitivity, for serum interferon titres are decreased by more than 90% in C3H/He mice after one total body X-irradiation of 250 r. Moreover, the species specificity of interferon has enabled us to show that circulating interferon induced by Newcastle disease virus (NDV) is of donor type in xenogeneic radiochimaeras, from which we concluded that cells responsible for interferon synthesis with this virus originate from haemopoietic stem cells3,4. Both granulocytes and lymphocytes fulfil the criteria of very radiosensitive elements derived from haemopoietic stem cells5,6. We wish to report that myxovirus-induced circulating interferon production is selectively depressed after administration of antilymphocyte serum (ALS). 相似文献
REDUCED glutathione (GHS) is maintained in substantial concentration (3 × 10?3 M) within neurones1. The availability of new thiol-oxidizing agents like diamide2,3, which freely enter cells and the principal action of which is to reduce the GSH concentration by conversion to GSSG (equation 1), promoted an investigation of the effects of these agents on release of transmitter at frog myoneural junctions. illustration