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1.
Maria L. Boccia Martin L. Reite Kristine Kaemingk Polly Held Mark L. Laudenslager 《Primates; journal of primatology》1991,32(2):255-263
The social environment affects both behavioral and physiological responses to separation from the mother. Less information
is available on the impact of the social environment on the response to separation in peer-reared infant monkeys. This study
reports the responses of peer-reared pigtail macaque infants to repeated separations, and the impact of social versus isolation
housing during the separation. The responses of two pairs of monkeys were studied during four three-day separations. One of
each pair was housed in isolation during the separation, and the other was with another pair of peers, with whom they had
been living for one month prior to the separation. The isolation-housed peer responded to the separation with behavioral agitation,
but no depression. The socially-housed peer's behavior did not differ from baseline during the separation. During successive
reunions, all the separated monkeys, regardless of housing condition, exhibited declining levels of behaviors related to maintaining
proximity to their attachment figure. Although the number of subjects is small, the results suggest that the presence of social
support, in the form of a familiar peer, can ameliorate the response to separation, and that with repeated separations the
responses of the monkeys changes significantly. 相似文献
2.
Oxygen concentration regulates EGF-induced proliferation and EGF-receptor down regulation 总被引:2,自引:0,他引:2
D A Wing G D Talley T G Storch 《Biochemical and biophysical research communications》1988,153(3):952-958
Reducing oxygen from 20% to 2.5% increases EGF-induced DNA synthesis and cell proliferation in cultures of human diploid fibroblasts. Reducing oxygen also changes the pattern of EGF binding to the cell surface. The loss of surface binding that follows EGF attachment to cells in 20% oxygen does not occur in 2.5% oxygen. 相似文献
3.
Genes for human U4 small nuclear RNA 总被引:10,自引:0,他引:10
4.
Survival of Shigella in Sewage: II. Effect of Glycerol on Shigella flexneri and Shigella Bacteriophage1 下载免费PDF全文
Glycerol (30%) inhibited or delayed the adsorption of Shigella bacteriophage on its host organism, S. flexneri II; glycerol also inhibited or delayed the burst of phage, whether or not adsorption was carried out in the presence of glycerol. Studies of the mechanisms of these effects showed that viscosity and osmotic shock probably were not responsible for either phenomenon. The inhibition of adsorption, however, was proportional to the concentration of glycerol, and appeared to be a function of the hydroxyl groups on the glycerol molecule. The inhibition of burst seemed to be related to the osmotic pressure outside the bacterial cells. 相似文献
5.
Polly A. Penhale 《Journal of experimental marine biology and ecology》1977,26(2):211-224
The biomass, productivity (14C), and photosynthetic response to light and temperature of eelgrass, Zostera marina L. and its epiphytes was measured in a shallow estuarine system near Beaufort, North Carolina, during 1974. The maximum of the biomass (above-ground) was measured in March; this was followed by a general decline throughout the rest of the year. The average biomass was 105.0 g dry wt m?2; 80.3 g dry wt m?2 was eelgrass and 24.7 g dry wt m?2 was epiphytes. The productivity of eelgrass averaged 0.88 mg C g?1 h?1 which was similar to that of the epiphytes, 0.65 mg C g?1 h?1. Eelgrass and epiphyte productivity was low during the spring and early summer, gave a maximum during late summer and fall, and declined during the winter; this progression was probably due to environmental factors associated with tidal heights. On an areal basis, the average annual productivity was 0.9 g C m?2 day?1 for eelgrass and 0.2 g C m?2 day?1 for the epiphytes. Rates of photosynthesis of both eelgrass and epiphytes increased with increasing temperature to an asymptotic value at which the system was light saturated. Both eelgrass and epiphytes had a temperature optimum of < 29 °C. A negative response to higher temperatures was also reflected in biomass measurements which showed the destruction of eelgrass with increasing summer temperatures. The data suggest that the primary productivity cycles of macrophytes and epiphytes are closely interrelated. 相似文献
6.
7.
Morphology and lactose synthesis in tissue culture of mammary alveoli isolated from lactating mice 总被引:1,自引:0,他引:1
Polly R. Cline Paul O. Zamora Howard L. Hosick 《In vitro cellular & developmental biology. Plant》1982,18(8):694-702
Summary Mammary epithelial cells from lactating mice synthesize and secrete lactose in culture and retain many features of their in
vivo morphology if mammary glands are only partially dissociated to alveoli, rather than completely dissociated to single
cells. After 5 d in culture lactose synthesis by alveoli cultured on floating collagen gels is 10 to 20 times higher than
in cultures of single cells on floating collagen gels. Moreover, mammary alveoli in culture retain sensitivity to lactogenic
hormones; the synthesis of lactose by alveoli depends on the continued presence of insulin and either hydrocortisone or prolactin.
In addition, within alveoli the original juxtaposition of constituent epithelial cells is retained, and cells are cuboidal
and have many microvilli and fat droplets. In contrast, alveoli on attached gels flatten and lose their secretory morphology.
These results indicate that the shape of the cells, presence of lactogenic hormones, and maintenance of epithelial:epithelial
cell contacts are required for maintenance of mammary epithelial cell differentiation in culture.
This research was supported by Grants CA-16392 and AG-02909 from the National Institutes of Health and Institutional Grant
IN 119 from the American Cancer Society. 相似文献
8.
9.
EcoHealth - West Nile virus (WNV) is the most significant mosquito-borne disease affecting humans in the United States. Eastern redcedar (ERC) is a native encroaching plant in the southern Great... 相似文献
10.
C Rodríguez-Burford D K Oelschlager L I Talley M N Barnes E E Partridge 《Biotechnic & histochemistry》2013,88(1):17-21
We describe here a computational morphology-based approach to the investigation of possible causes of chromatin alterations in sperm. A comprehensive set of state-of-the-art and geometric measures are computationally extracted from toluidine blue stained images and analyzed to infer the possible processes leading to normal and abnormal chromatin formation while seeking a possible taxonomy of chromatin alterations and their influence on sperm head morphology. Using this methodology, we have identified higher chromatin fragility at some specific points of the sperm head. Despite the lack of correlation between morphologies of sperm head and chromatin structure, four main morphological types of chromatin alterations in bull spermatozoa have been identified and their possible causes discussed. 相似文献