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A. Birkenfeld Y. Ezra N. Ron D. Navot S. Granovsky J. G. Schenker I. S. Levij I. Vlodavsky 《In vitro cellular & developmental biology. Plant》1988,24(12):1188-1192
Summary The culturing of human endometrium in conventional plastic dishes and media is only partially successful, mainly because a
growth of a heterogeneous population of cells is achieved. Naturally produced extracellular matrix closely resembles the subepithelial
basement membrane and seems to affect both growth and differentiation of cells. These qualities of the extracellular matrix
(ECM) were applied for obtaining endometrial epithelial cultures. Endometrial tissue specimens were plated after slicing on
ECM-coated dishes and kept for up to 8 d. The growth of a confluent homogeneous tissue composed of polygonal epithelial-like
cells was demonstrated. To further characterize these cells, cultures were examined by scanning electron microscopy and transmission
electron microscopy. Scanning electron microscopy revealed flattened polygonal cells covered with microvilli, among which
ciliated cells were observed. By transmission electron microscopy the cells were seen as a monolayer, with some cells overlapping,
closely adherent to the matrix. Microvilli, as well as intracellular vacuoles and glycogen granules were observed. Cell type
specific cytoskeletal markers were demonstrated by antibodies to intermediate filament proteins (keratin and epithelial membrane
antigen). Taken together, the morphologic and immunohistochemical studies indicate that a selective growth of the epithelial
component of endometrial tissue was obtained after plating unprocessed endometrial tissue fragments on ECM-coated culture
dishes.
This work was supported by PHS grant no. CA 30289 to J.V. 相似文献
3.
On the Relation between Effector Concentration and the Rate of Induced Enzyme Synthesis 总被引:6,自引:0,他引:6 下载免费PDF全文
The Jacob and Monod scheme for the regulation of enzyme formation leads to the following relation between the relative rate of enzyme synthesis α and cellular effector concentration E (the lower sign is for repressible systems): log (α/1 - α - αb) = ± n log [E] + log αb ± log K1. This equation permits linear plotting of experimental data and the evaluation of three quantities: n, the number of effector molecules combining with a repressor molecule, K1, the dissociation constant of this interaction and K2/Rt, the ratio of repressor-operator dissociation constant to total repressor concentration. Measurements on the repression of alkaline phosphatase in Escherichia coli as a function of phosphate concentration are reported and fit the proposed equation with n = 1, indicating that the binding of a single phosphate to the repressor species may be sufficient to cause repression. K1 of this interaction was found to be 0.58 ±0.11 × 10-3 M. The available data regarding the enzymes of the lac operon in a variety of E. coli strains, and several other enzymes are analyzed. It is confirmed that the lac repressor interacts with 2 isopropyl thiogalactoside (IPTG) molecules to relieve repression with a K1 = 50 ±20 × 10-12 M2. In some strains, separate binding constants for the first and second IPTG molecules can be evaluated. 相似文献
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The effect of (2''-5'') and (3''-5'') phosphodiester linkages on conformational and stacking properties of cytidylyl-cytidine in aqueous solution. 下载免费PDF全文
Conformational properties of (2'-5') and (3'-5') CpC have been determined by proton magnetic resonance spectroscopy at 220 MHz. The ribose ring structures are predominantly 3E with the exception of the ring from the 2'-phosphate fragment of C(2'-5')pC which exhibits an 2E pucker. Bases are oriented anti with respect to the ribose and the conformations about C4'-C5', C5'-O5', C3'-O3' (C2'-O2') are gg, g'g', and g+ in equilibrium g-, respectively. The dimers exist as mixtures of stacked (g+g+ and g-g- about the P-O(C) bonds) and unstacked species at 20 degrees C. Stacking is estimated to be 35% in both dimers. 相似文献
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Genetic location of the gene (ush) specifying periplasmic uridine 5'-diphosphate glucose hydrolase (5'-nucleotidase) in Escherichia coli K-12. 总被引:5,自引:4,他引:1 下载免费PDF全文
Further genetic mapping to two- and three-factor crosses show that the ush gene is closely linked to two other genes hemG and pisA, and that the probable gene order is proC-hemG-plsA-ush-gal. 相似文献
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Dominant Microbial Populations in Limestone-Corroding Stream Biofilms, Frasassi Cave System, Italy 总被引:1,自引:2,他引:1 下载免费PDF全文
Jennifer L. Macalady Ezra H. Lyon Bess Koffman Lindsey K. Albertson Katja Meyer Sandro Galdenzi Sandro Mariani 《Applied microbiology》2006,72(8):5596-5609
Waters from an extensive sulfide-rich aquifer emerge in the Frasassi cave system, where they mix with oxygen-rich percolating water and cave air over a large surface area. The actively forming cave complex hosts a microbial community, including conspicuous white biofilms coating surfaces in cave streams, that is isolated from surface sources of C and N. Two distinct biofilm morphologies were observed in the streams over a 4-year period. Bacterial 16S rDNA libraries were constructed from samples of each biofilm type collected from Grotta Sulfurea in 2002. β-, γ-, δ-, and -proteobacteria in sulfur-cycling clades accounted for ≥75% of clones in both biofilms. Sulfate-reducing and sulfur-disproportionating δ-proteobacterial sequences in the clone libraries were abundant and diverse (34% of phylotypes). Biofilm samples of both types were later collected at the same location and at an additional sample site in Ramo Sulfureo and examined, using fluorescence in situ hybridization (FISH). The biomass of all six stream biofilms was dominated by filamentous γ-proteobacteria with Beggiatoa-like and/or Thiothrix-like cells containing abundant sulfur inclusions. The biomass of -proteobacteria detected using FISH was consistently small, ranging from 0 to less than 15% of the total biomass. Our results suggest that S cycling within the stream biofilms is an important feature of the cave biogeochemistry. Such cycling represents positive biological feedback to sulfuric acid speleogenesis and related processes that create subsurface porosity in carbonate rocks. 相似文献
10.
Eugenia Voziyanova Natalia Malchin Rachelle P. Anderson Ezra Yagil Mikhail Kolot Yuri Voziyanov 《Nucleic acids research》2013,41(12):e125
Recombinase-mediated cassette exchange, or RMCE, is a clean approach of gene delivery into a desired chromosomal location, as it is able to insert only the required sequences, leaving behind the unwanted ones. RMCE can be mediated by a single site-specific DNA recombinase or by two recombinases with different target specificities (dual RMCE). Recently, using the Flp–Cre recombinase pair, dual RMCE proved to be efficient, provided the relative ratio of the enzymes during the reaction is optimal. In the present report, we analyzed how the efficiency of dual RMCE mediated by the Flp–Int (HK022) pair depends on the variable input of the recombinases—the amount of the recombinase expression vectors added at transfection—and on the order of the addition of these vectors: sequential or simultaneous. We found that both in the sequential and the simultaneous modes, the efficiency of dual RMCE was critically dependent on the absolute and the relative concentrations of the Flp and Int expression vectors. Under optimal conditions, the efficiency of ‘simultaneous’ dual RMCE reached ∼12% of the transfected cells. Our results underline the importance of fine-tuning the reaction conditions for achieving the highest levels of dual RMCE. 相似文献