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Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections 总被引:15,自引:4,他引:11
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A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules. 相似文献
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AV Shevchenko IG Budzanivska TP Shevchenko VP Polischuk D Spaar 《Archives Of Phytopathology And Plant Protection》2013,46(2):139-146
The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants. 相似文献
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Usdin K; Chevret P; Catzeflis FM; Verona R; Furano AV 《Molecular biology and evolution》1995,12(1):73-82
The single most difficult problem in phylogenetic analysis is deciding
whether a shared taxonomic character is due to common ancestry or one that
appeared independently due to convergence, parallelism, or reversion to an
ancestral state. Mammalian L1 retrotransposons undergo periodic
amplifications in which multiple copies of the elements are interspersed in
the genome. Because these elements apparently are transmitted only by
inheritance and are retained in the genome, a shared L1 amplification event
can only be an inherited ancestral character. We propose that L1
amplification events can be an excellent tool for analyzing mammalian
evolution and demonstrate here how we addressed several refractory problems
in rodent systematics using L1 DNA as a taxonomic character.
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Sabina Iluta Sergiu Pasca Grigore Gafencu Ancuta Jurj Andreea Terec Patric Teodorescu Cristina Selicean Ciprian Jitaru Alexandra Preda Diana Cenariu Catalin Constantinescu Maria Iordache Bogdan Tigu Raluca Munteanu Richard Feder Delia Dima Mihnea Zdrenghea Diana Gulei Tudor-Eliade Ciuleanu Ciprian Tomuleasa 《Journal of cellular and molecular medicine》2021,25(13):6094-6102
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Fibroblast dynamics as an in vitro screening platform for anti‐fibrotic drugs in primary myelofibrosis
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Ciprian Tomuleasa MD PhD Sonia Selicean MD Grigore Gafencu MD Bobe Petrushev MD Laura Pop PhD Cristian Berce PhD Anca Jurj PhD Adrian Trifa MD PhD Ana‐Maria Rosu MD Sergiu Pasca MD Lorand Magdo MD Mihnea Zdrenghea MD PhD Delia Dima MD PhD Alina Tanase MD PhD Ioana Frinc MD Anca Bojan MD Ioana Berindan‐Neagoe PhD Gabriel Ghiaur MD PhD Stefan O. Ciurea MD 《Journal of cellular physiology》2018,233(1):422-433
Although the cause for bone marrow fibrosis in patients with myelofibrosis remains controversial, it has been hypothesized that it is caused by extensive fibroblast proliferation under the influence of cytokines generated by the malignant megakaryocytes. Moreover, there is no known drug therapy which could reverse the process. We studied the fibroblasts in a novel system using the hanging drop method, evaluated whether the fibroblasts obtain from patients are part of the malignant clone of not and, using this system, we screen a large library of FDA‐approved drugs to identify potential drugs candidates that might be useful in the treatment of this disease, specifically which would inhibit fibroblast proliferation and the development of bone marrow fibrosis. We have found that the BM fibroblasts are not part of the malignant clone, as previously suspected and two immunosuppressive medications—cyclosporine and mycophenolate mophetil, as most potent suppressors of the fibroblast collagen production thus potentially inhibitors of bone marrow fibrosis production in myelofibrosis. 相似文献
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R Alan Harris Dorottya Nagy-Szakal Sabina AV Mir Eibe Frank Reka Szigeti Jess L Kaplan Jiri Bronsky Antone Opekun George D Ferry Harland Winter Richard Kellermayer 《Epigenetics》2014,9(8):1131-1137
Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD. 相似文献
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Anca Gafencu Mihaela Stanescu Aurel Mircia Toderici Constantina Heltianu M. Simionescu 《Cell and tissue research》1998,293(1):101-110
In endothelial cells (EC), caveolae or plasmalemmal vesicles (PVs) represent a structurally and biochemically specialized membrane microdomain. Since few data are available on the biochemical composition of PVs of large vessel endothelium, we have designed experiments to isolate this domain and to analyze its chemical components. A highly purified apical membrane fraction was obtained from cultured bovine aortic EC by using cationic colloidal silica (silica-ap), or the EC were surface-radioiodinated and a cell homogenate was prepared. Detergent treatment (Triton X-100; TX) and mechanical disruption of both the silica-ap fraction and cell homogenate followed by ultracentrifugation on a sucrose gradient gave detergent-soluble and detergent-insoluble membranous fractions. The lowest density TX-insoluble fraction appeared morphologically as distinct vesicles (caveolae; 60?nm average diameter; PVs fraction). Biochemical characterization of the PVs fraction (by comparison with the soluble fraction) revealed the presence, at high concentration, of specific caveolar markers, viz., caveolin (both isoforms, the 24-kDa form being conspicuously more abundant) and Ca2+-ATPase. By contrast, angiotensin-converting enzyme and alkaline phosphodiesterase were present almost exclusively in the TX-soluble fraction. The glycoproteins in the PVs fraction were of apparent molecular weights 52, 68, 95, and 114?kDa. Analysis of the fatty acid composition revealed more palmitoleic and stearic acid in the PVs fraction then in the TX-soluble fraction. Thus, in comparison with the plasmalemma proper, the PVs fraction (1) is detergent-insoluble; (2) contains caveolin in two isoforms; (3) contains Ca2+-ATPase at high concentration; (4) contains a set of specific glycoproteins; and (5) is enriched in palmitoleic and stearic acids. 相似文献
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AV. H. HEWOOD EDITAE 《Botanical journal of the Linnean Society. Linnean Society of London》1979,78(3):235-236
Following the publication of the last of the series of Flora Europaea Notulae, No. 20 in the Botanical Journal of the Linnean Society , 76: 297–384 (1978), a number of additions or alterations have been drawn to our attention. These are published in continuation. 相似文献