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21.
A method for the rapid establishment of normal adult mammalian colonic epithelial cell cultures 总被引:6,自引:0,他引:6
Alda Vidrich Rajeswari Ravindranath Kianbanoo Farsi Stephan Targan 《In vitro cellular & developmental biology. Plant》1988,24(3):188-194
Summary Normal colonic epithelial cell cultures of mammalian origin are required to facilitate the study of both normal cellular functions
as well as pathogenesis of certain (human) colonic diseases. To date, little information is available regarding the growth
requirements of colonic epithelial cells in culture of eitehr animal or human origin. Such data would enable the development
of a long-term culture system for these cells. In this study, we present methodology that results in the establishment of
homogeneous cultures of adult rabbit colonic epithelial reproducibly, quickly, and in quantity. The epithelial nature of the
cultures is unambiguously established by intermediate filament typing using antikeratin antibodies. Such culutres can now
be used for a variety of functional studies as well as to investigate the growth requirements of colonic epithelial in culture.
This work was supported by the Blinder Foundation for Crohn’s Disease Research, Harbor UCLA IBD Center (AM 36200) and grant
AM 27806 from the National Institutes of Health, Bethesda, MD. 相似文献
22.
Stephan Schneider Albrecht Fischer Adriaan W.C. Dorresteijn 《Development genes and evolution》1992,201(4):243-256
Summary Early development of Platynereis massiliensis was studied in serial sections of fixed embryos and in living or fixed embryos whose nuclei had been made visible with a fluorescent label. The unfertilized egg is an ellipsoid with three axes of differing length. The longest axis corresponds to the dorsoventral axis of the developing embryo. Egg volume is ten times that in the sibling species, P. dumerilii, mainly due to increased yolk content. The timing and spatial pattern of cleavage were observed from first cleavage to the 62-cell stage. Volumes of the blastomeres, their nuclei, their yolk-free cytoplasm and their yolk were determined from serial sections up to the 29-cell stage. In the P. massiliensis embryo, cell cycles are on average 3.7 times longer than in P. dumerilii; volume proportions among the blastomeres also differ and the macromeres containing the bulk of yolk are particularly large, but otherwise the cleavage patterns, differential segregation of yolk and yolk-free cytoplasm, and the histogenetic fates of the blastomeres are the same as in P. dumerilii. This equivalence of cell lineage and of cytoplasmic segregation mechanisms in both species, maintained in spite of the different appearance of the embryos, suggests functional importance of and selective constraint on these developmental features. The relatively accelerated divisions of the 2d cell line in P. massiliensis may be interpreted as the precocious development of cell lines which give rise to adult structures. Several structures, obviously functional in developing P. dumerilii, have lost their function in P. massiliensis: the egg contains few cortical granules, giving rise to only a moderate egg jelly layer in the zygote; prototroch cells develop cilia, but the heavy embryo is unable to swim; the larva develops three pairs of parapodia but, unlike the corresponding stage in P. dumerilii, is not capable of coordinate locomotion. This loss of motility is related to the brooding habit of the species developing inside the parental tube and is explained as the result of a switch from pelagic to benthic, protected reproduction in P. massiliensis.
Offprint requests to: A.W.C. Dorresteijn 相似文献
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Achim G. Rieth Stephan L. Baader Holger N. Lode Gernot Bruchelt Dietrich Niethammer 《Biometals》1992,5(4):223-227
Damage of CCC PM2 DNA by 6-hydroxydopamine (6-OHDA) and ascorbic acid (AA), compounds that are both able to release iron from ferritin, was significantly enhanced in the presence of ferritin. H2O2, a product of 6-OHDA autoxidation, did not induce DNA strand breaks in the absence of ferritin and only to a minor extent in the presence of ferritin. DNA damage by 6-OHDA and AA could be reduced by the hydroxyl radical scavenger mannitol, the iron chelator desferrioxamine, and, partly, by a combination of superoxide dismutase and catalase. These inhibitory effects were clearly less pronounced in the presence of ferritin. Ferritin obviously played an important role as a source of iron in the pro-oxidative processes of 6-OHDA and AA. These features might be of importance in cancer therapy since many tumor cells contain elevated ferritin levels. 相似文献
26.
Peter Heimann Stephan Laage Harald Jockusch 《Differentiation; research in biological diversity》1991,47(2):77-83
In the wobbler (WR) mouse, a neuromuscular mutant characterized by a motoneuron degeneration and male infertility, the cellular basis of the defect in spermiogenesis was studied by light and electron microscopy as well as by lectin binding. Spermatozoa of the wobbler mutant had rounded heads, and their motility was reduced. In histological sections of WR testes, spermatogenesis appeared normal up to the stage of round spermatids, but the elongation and flattening of the nucleus during late spermiogenesis did not occur. Numbers of spermatid nuclei in WR testes were reduced to 70%-80% of controls. The acrosomal marker glycoprotein, peanut agglutinin receptor, was synthesized, but the acrosomal membrane did not attach to the nucleus. The disturbance in spermiogenesis of the wobbler mouse is not due to impaired descent of the testis, nor to a lack of testosterone, and is distinct from that observed in other mouse mutants (quaking, QK; Purkinje cell degeneration, PCD) with combined neurological and spermiogenesis defects. 相似文献
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28.
The Evolution of Restricted Recombination and the Accumulation of Repeated DNA Sequences 总被引:19,自引:6,他引:13 下载免费PDF全文
We suggest hypotheses to account for two major features of chromosomal organization in higher eukaryotes. The first of these is the general restriction of crossing over in the neighborhood of centromeres and telomeres. We propose that this is a consequence of selection for reduced rates of unequal exchange between repeated DNA sequences for which the copy number is subject to stabilizing selection: microtubule binding sites, in the case of centromeres, and the short repeated sequences needed for terminal replication of a linear DNA molecule, in the case of telomeres. An association between proximal crossing over and nondisjunction would also favor the restriction of crossing over near the centromere. The second feature is the association between highly repeated DNA sequences of no obvious functional significance and regions of restricted crossing over. We show that highly repeated sequences are likely to persist longest (over evolutionary time) when crossing over is infrequent. This is because unequal exchange among repeated sequences generates single copy sequences, and a population that becomes fixed for a single copy sequence by drift remains in this state indefinitely (in the absence of gene amplification processes). Increased rates of exchange thus speed up the process of stochastic loss of repeated sequences. 相似文献
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30.
Wolfgang Hagmann Claudio Denzlinger Stephan Rapp Gisbert Weckbecker Dietrich Keppler 《Prostaglandins & other lipid mediators》1986,31(2)
Mercapturic acid formation, an established pathway in the detoxication of xenobiotics, is demonstrated for cysteinyl leukotrienes generated in rats
after endotoxin treatment. The mercapturate N-acetyl-leukotriene E4 (N-acetyl-LTE4) represented a major metabolite eliminated into bile after injection of [3H]LTC4 as shown by cochromatography with synthetic N-acetyl-LTE4 in four different HPLC solvent systems. The identity of endogenoud N-acetyl-LTE4 elicited by endotoxin
was additionally verified by enzymatic deacetylation followed by chemical N-acetylation. The deacetylation was catalyzed by penicillin amidase. Endogenous cysteinyl leukotrienes were quantified by radioimmunoassay after HPLC separation. A N-acetyl-LTE4 concentration of 80 nmol/l was determined in bile collected between 30 and 60 min after endotoxin injection. Under this condition, other cysteinyl leukotrienes detected in bile by radioimmunoassay amounted to less than 5% of N-acetyl-LTE4. The mercapturic acid pathway, leading from the glutathione conjugate LTC4 to N-acetyl-LTE4, thus plays an important role in the deactivation and elimination of these potent endogenous mediators. 相似文献