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101.
The free (non-conjugated) ecdysteroid in the ovaries during the first gonadotrophic cycle of Diploptera punctata was identified as 20-hydroxyecdysone. The hormone, quantified by radioimmunoassay and by ultraviolet absorbance, was detectable in the ovary toward the end of vitellogenesis; the quantity increased rapidly during chorion formation. Ovaries with chorionated eggs contained 67 μg of 20-hydroxyecdysone per g fresh weight. The haemolymph free-ecdysteroid, not identified physicochemically, was quantified by radioimmunoassays. The highest concentration was observed at adult emergence; the titre declined between days 1–3 and then remained at a relatively constant level through oviposition (which occurs between day 7 and 8); titres in pregnant females were higher. Ovariectomized females exhibited the same pattern of ecdysteroid titres in the haemolymph as the sham operated controls throughout the period corresponding to the first gonadotrophic cycle. Thus the ovary may not be the only source of haemolymph ecdysteroid related to reproduction in adult females.  相似文献   
102.
Dynamics of orange peel fermentation during ensilage   总被引:2,自引:0,他引:2  
The dynamics of fermentation during ensilage were studied on orange peel (variety Shamouti) ensiled in 50 plastic containers, 10 kg in each, with an outlet for seepage. At predetermined intervals the containers were weighed and samples were taken from three of them for chemical and microbial analysis. Fermentation losses amounted to up to ca one-third of the fresh peel dry matter (DM) content. Most losses occurred within 10 d of commencement of fermentation, and were attributable to gas release. The major fermentation products were ethanol, lactic and acetic acids (16, 3 and 3% of DM, respectively). The dominant microbial populations were lactobacilli and yeasts. Tests are in progress to inhibit the yeasts and thereby reduce fermentation losses.  相似文献   
103.
Summary Using both normal and transformed rat liver epithelial cells to prepare cytoplasmic hybrids (cybrids) we have found evidence to support the theory that the cytoplasm from a normal cell can suppress tumorigenicity. A unique aspect of this study is that all of the cells utilized, both normal and malignantly transformed, were derived from an original cloned cell. We found that fusing cytoplasts from normal cells to malignantly transformed whole cells resulted in cybrid clones which, when injected into newborn rat pups, isogenic with those from which the cell culture was initiated, yielted tumors in 51% of the animals injected compared to 92% of the animals injected with the tumorigenic parent. Those animals that did develop tumors from the cybrid cells survived longer than those injected with cells from the tumorigenic parent. Thus, the cybrid, formed of cytoplasm from both parents, was less tumorigenic than the malignantly transformed parent cell. When reconstituted cells were prepared by fusing cytoplasts from normal cells with karyoplasts from malignantly transformed cells, a situation in which essentially all of the cytoplasm of the reconstituted cell is derived from normal cells, the tumorigenic phenotype was extinguished. This work was supported in part by United States Public Health Service grant CA12056, and grant CA09100 from the National Cancer Institute, Bethesda, MD. This work is partial fulfillment for the degree of Doctor of Philosophy for B.A.I.  相似文献   
104.
We have quantitatively documented the development of sex differences in the behavior of juvenile Japanese macaques (1 to 2 years of age). Mothers treated their offspring differently by sex, i.e., mothers of males broke contact with them more frequently than did mothers of females. Juvenile males played more, and mounted other macaques more frequently; juvenile females groomed their mothers more and were also punished by other group members more frequently than were males. Males showed a pattern of decreasing interactions with their mothers, but females increased the frequency of their maternal interactions. These patterns appear to presage the life histories of the sexes. However, comparisons with other species of nonhuman primates indicate that although sex differences in behavior are common, the variability among species severely limits cross-specific generalizations.  相似文献   
105.
Analyses for phytate by an indirect precipitation method and for the minerals calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), and manganese (Mn) by atomic absorption spectrophotometry were carried out on 100 foods available in New Zealand. Foods with 1% phytate (dry weight basis) included untoasted muesli, rolled oats, wheat germ, wheat bran, soybean, and some soy products. Most breads contained between 0.35 and 0.60% phytate; legumes on average had 0.62% phytate, as did snack bars. There was a wide variation in Ca and Zn contents: There was a tenfold variation in Ca content among the legume products, whereas there was a seventyfold variation in Zn content among the cereals. The phytate: Zn molar ratio, which is presumed to indicate the biovailability of Zn, was above 20∶1 for two-thirds of the cereals and almost all of the snack bars; it was above 15∶1 for one-third of the breads, almost all of the legumes, and half of the legume products. These high phytate: Zn molar ratios, as well as some Ca: phytate molar ratios above 6∶1, indicate that there might be a reduced biovailability of Zn in many of the foods analyzed in this study.  相似文献   
106.
We have provided data relating Cd concentration in tissue to about a 40-fold range in blood Cd concentration. Osmotic pumps containing cadmium chloride were subcutaneously implanted in male New Zealand white rabbits. The pumps continuously delivered either 0.15 or 1.5 mg Cd/d. Blood and plasma levels of Cd were measured weekly throughout the study. After 28 d, the rabbits were killed and tissue concentrations of Cd determined by atomic absorption spectrophotometry. Less than 10% of the total Cd in the blood was carried in the plasma, the remainder was associated with the blood cells, where it was bound mainly to metallothionein. We found the blood and tissue levels of Cd were correlated for each tissue we investigated. There was a wide range in affinity of the tissues for Cd; liver and kidney had the highest Cd uptake, whereas brain affinity was about 500 times less than liver.  相似文献   
107.
The behavioral interactions of 22 infant and mother Japanese macaques with other group members were studied. Focal-animal observations were made from the time of each infant’s birth until 1 year of age. Infants and mothers both displayed exceedingly strong preferences for associating with matrilineal kin and, specifically, for female kin. The degree of genetic relatedness was positively correlated with levels of spatial proximity, contact, grooming, aggression, and play. Overall frequencies of interactions with nonkin were very low, and partner sex was not an important factor in interactions with nonkin. There were no significant differences between male and female infants in interactions with kin versus nonkin. There was only one significant difference between male and female infants in interactions with males versus females: female infants showed stronger preferences for initiating proximity with females over males than did male infants. Because mothers provide the focal point for infant interactions during the first year of life, we compared the behavior of infants and mothers. Mothers were the recipients of more social interactions than were infants, mothers engaged in more grooming than did infants, and infants engaged in more social play than did mothers. These findings are only partially consistent with kin-selection theory, and the inadequacies of studying matrilineal kin discrimination to test kin selection are reviewed. The near-absence of infant sex differences in associations with social partners suggests that although maternal kin other than the mother are important to infant socialization, they probably do not contribute to the development of behavioral sex differences until after the first year of life.  相似文献   
108.
Quantitative data are presented on the effects of subject sex, partner sex,and kinship on the social interactions of 18 juveniles of the Oregon troop of Japanese macaques (Macaca fuscata).Data on these subjects as infants were also used to detail maturational changes in partner sex preferences. Nine males and nine females, whose multiparous mothers represented a cross section of dominance ranks, were observed using a focal-animal technique. Juveniles of both sexes engaged in more proximity, contact, grooming, mounting, aggression, and social play with kin than with nonkin partners. They initiated less contact with females and more contact with males during their second year. They initiated more grooming and aggression during their second year than their first year, with females displaying a strong preference for grooming females and males specifically aggressing males more during the second year. Aggression was higher between same-sexed partners than between opposite-sexed partners. Males engaged in more social interactions with males during the second year than the first year of life. Males played more than females during both years. Males played more with males during the second year than the first year, and males played with males more than did females during the second year. We conclude that sex differences in behavioral frequencies become evident during the first year of life, and sex differences in partner preferences emerge during the second year of life.  相似文献   
109.
The ammonium uptake system of Rhodobacter capsulatus B100 was examined using the ammonium analog methylammonium. This analog was not transported when cells were grown aerobically on ammonium. When cultured on glutamate as a nitrogen source, or when nitrogen-starved, cells would take up methylammonium. Therefore, in cells grown under nitrogen-limiting conditions, a second system of ammonium uptake (or a modified form of the first) is present which is distinguished by its capacity for transporting the analog in addition to ammonium. The methylammonium uptake system exhibited saturation kinetics with a K m of 22 M and a V max of about 3 nmol per min · mg protein. Ammonium completely inhibited analog transport with a K i in the range of 1 M. Once inside the cell methylammonium was rapidly converted to -N-methylglutamine; however, a small concentration gradient of methylammonium could still be observed. Kinetic parameters reflect the effects of assimilation.The methylammonium uptake system was temperature and pH dependent, and inhibition studies indicated that energy was required for the system to be operative. A glutamine auxotroph (G29) lacking the structural gene for glutanime synthetase did not accumulate the analog, even when nitrogen starved. The Nif- mutant J61, which is unable to express nitrogenase structural genes, also did not transport methylammonium, regardless of the nitrogen source for growth. However, the mutant exhibited wild-type ammonium uptake and glutamine synthetase activity. These data suggest that transport of ammonium is required for growth on limited nitrogen and is under the control of the Ntr system in R. capsulatus.Abbreviations CCCP carbonyl cyanide-m-chlorophenyl hydrazone - CHES cyclohexylaminoethanesulfonic acid - DMSO dimethyl sulfoxide - GMAD -N-methylglutamine - GS glutamine synthetase - MES 2-(N-morpholino) ethanesulfonic acid - MSX methionine-Dl-sulfoximine - pCMB p-chloromercuribenzoate - Tricine N-tris(hydroxymethyl)methylglycine  相似文献   
110.
Summary Over 600 hybridomas were derived from the immunization of mice with live cells and aqueous extracts of the human prostatic carcinoma cell line PC3. A total of 26 hybridomas with restricted reactivities were selected, subcloned and antibodies tested on a variety of tumor and normal cells. Seven monoclonal antibodies showed reactivity for prostate cancer and other tumor cell lines, including breast carcinomas. Three of the antibodies obtained after immunization with live cells reacted with live cells only and three of the four antibodies obtained after immunization with cell extract reacted with cell extracts and spent culture media. The fourth antibody in the latter group was reactive only in the immunoperoxidase staining assay. Antibody PrS5 recognized a 90,000 molecular weight molecule from 125I-surface-labeled cells in immunoprecipitation analysis. Antibodies PrE3 and PrD8 detected a nonacid glycolipid pentasaccharide from PC3 cells and meconium, and a glycoprotein of 115,000 molecular weight from 125I-surface-labeled red blood cells. The similar patterns of reactivity in RIAs and antigen analysis suggest that antibodies PrE3 and PrD8 recognize the same molecule. The results emphasize the usefulness of immunohistochemistry in the testing of monoclonal antibodies and the impact of the form in which the antigen is presented on the resultant antibody specificity  相似文献   
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