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41.
C G Francisco R Freire R Hernandez J A Salazar E Suarez G A García de la Mora J A Noguez A Acosta O Jimeno 《Steroids》1983,41(3):267-275
The synthesis of nine new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described, with the esterifying acids bearing an acetylenic or olefinic function in a chain of eight or nine carbon atoms, for evaluation as long-acting contraceptive agents. 相似文献
42.
Antonio G. Gonzalez Jaime Bermejo Barrera Francisco J. Tolfdo Marante 《Phytochemistry》1983,22(4):1049-1050
The fruit bodies of the Basidiomycete Scleroderma polyrhizum have been shown to contain the steroids ergosta-4,6,8(14) 22-tetraen-3-one and 5α,8α-epidoxyergosta-6,22-dien-3β-ol and also palmitic and oleic acids. 相似文献
43.
Lipopolysaccharides of two strains of the phototrophic bacterium Rhodopseudomonas capsulata 总被引:1,自引:0,他引:1
The lipopolysaccharides of Rhodopseudomonas capsulata strains St. Louis (ATCC 23782) and Sp 11 both contain L-acofriose, rhamnose, glucose and glucosamine as the main sugar constituents. 2-Keto-3-deoxyoctonate and neuraminic acid were tentatively identified. The fatty acid spectrum found with both strains comprises 3-OH-C10 and C12:1 (ester-linked) and 3-oxo-C14 (amide-linked). Isolated lipid A from strain Sp 11 contains glucosamine, glucosamine-phosphate and the total of the fatty acids of the lipopolysaccharide. Methylation analysis of the degraded polysaccharide of this lipopolysaccharide shows L-acofriose in both terminal and 1 leads to 2 chain-linked positions in a 1:4 molar ratio. Rhamnose is exclusively chain-linked (1 leads to 2), glucose is both terminally and chain-linked (1 leads to 6) in a 1:1 molar ratio. The serological activity of the lipopolysaccharide of both the R. capsulata strains is low in antisera against living or heat-killed cells when tested by passive hemagglutination, Ouchterlony immunoprecipitation or gel-immunoelectrophoresis. No crossreaction was observed among the lipopolysaccharides of R. capsulata strains St. Louis, Sp 11 and 37b4 in immunoprecipitation. Lipopolysaccharide of strain Sp 11 was found to lack lethal toxicity in galactosamine-sensitized mice. 相似文献
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The results of 11 experiments with Drosophila species show that fertility is not a reducible property: the fertility of a mating pair cannot be predicted from the average fertility of the two genotypes involved. We propose a model of fertility selection that does not assume additivity (or multiplicativity) but assumes random mating and that the genotypic frequencies are in Hardy-Weinberg equilibrium. Numerical simulations show that removal of the assumption of Hardy-Weinberg frequencies does not significantly change the equilibrium frequencies predicted by the model. 相似文献
47.
Human arterial smooth muscle cells in culture: Inverse relationship between proliferation and expression of contractile proteins 总被引:5,自引:0,他引:5
Gunnar Fager Göran K. Hansson Allen M. Gown David M. Larson Omar Skalli Göran Bondjers 《In vitro cellular & developmental biology. Plant》1989,25(6):511-520
Summary Human arterial smooth muscle cells (hASMC) from explants of the inner media of uterine arteries were studied in secondary
culture. We had previously found that these cells depend on exogenous platelet-derived growth factor (PDGF) for proliferation
in vitro. Deprivation of the serum mitogen(s) by culture in plasma-derived serum or bovine serum albumin (BSA) caused a true
growth arrest that was reversible upon reexposure to the mitogen(s). When added to serum-containing medium, heparin caused
a reversible growth arrest which could be competed for by increasing concentrations of serum. In the current study we used
a set of smooth muscle-specific actin and myosin, antibodies to study the expression of contractile proteins in stress fibers
under indirect immunofluorescence on hASMC in culture. Even in sparse culture, grwoth-arrested hASMC expressed stress fibers
containing these actin and myosin epitopes. This was true irrespective of whether growth arrest was achieved by culture in
media containing only BSA or a combination of heparin and whole blood serum. hASMC proliferating in whole blood serum in sparse
culture did not express such strees fibers, as judged by immunofluorescent staining. This was true also for cells that were
restimulated to proliferate in serum after a growth arrest. Utilizing a monoclonal antibody against a nuclear antigen expressed
in proliferating human cells, we were able to demonstrate an inverse relationship between the expression of this antigen and
the SMC-specific contractile proteins, respectively. Under these culture conditions, the reversible transition between defifferentiated
and differentiated hASMC was almost complete and terminated about 1 wk after the change in culture condition. We conclude
that hASMC in vitro respond, to exogenous PDGF by proliferation and dedifferetiation as a single population of cells. We also
conclude that this modulation is reversible, because the cells become uniformly quiescent and differentiated when the mitogenic
stimulus is blocked or removed.
This study was supported by grants from the Swedish Medical Research Council (Project no. 4531 and 6816), the Swedish Association
against Heart and Chest Diseases, the King Gustaf V and Queen Victoria Foundation, the National Institutes of Health, Bethesda,
MD (grant HL 29873) and the Swedish National Board for Laboratory Animals. 相似文献
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Summary TheDrosophila nasuta group consists of about 12 closely related species distributed throughout the Indo-Pacific region. They are of great interest because of their evolutionary idiosyncrasies including little morphological differentiation, the ability to intercross in the laboratory often producing fertile offspring, and substantial chromosomal evolution. Studies of metric traits, reproductive isolation, and chromosomal and enzyme polymorphisms have failed to resolve the phylogeny of the species. We report the results of a survey of the mitochondrial DNA (mtDNA) restriction patterns of the species. The phylogeny obtained is consistent with other available information and suggests thatD. albomicans may represent the ancestral lineage of the group. The amount of polymorphism in local populations (=1.0% per site) is within the typical range observed in other animals, includingDrosophila. The degree of differentiation between species is, however, low: the origin of the group is tentatively dated about 6–8 million years ago. This study confirms the usefulness of mtDNA restriction patterns for ascertaining the phylogeny of closely related species. 相似文献