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排序方式: 共有226条查询结果,搜索用时 15 毫秒
1.
A procedure was developed which allows the large-scale isolation of root hairs from seedlings of Pisum sativum . L. cvs. Kleine Rheinländerin and Rosa Krone. The method may yield up to 50 g fresh weight of root hairs per 3.104 seedlings. In a modified form considerable amounts of root hair material may be harvested, even after incubation of the roots in aqueous solutions. Thus, detailed biochemical studies on the root hair system have become feasible.
The occurrence of specific proteins in membrane fractions of P. sativum root hairs was demonstrated as follows: Incubation of root hairs in situ with 3-azidonaphthalene-2,7-disulfonate – a strongly anionic, photoactivated fluorescent marker – followed by gel electrophoresis of membrane fractions showed the presence of root-hair specific proteins which, since the system was intact, suggests that they are on the outer surface of the cells. 相似文献
The occurrence of specific proteins in membrane fractions of P. sativum root hairs was demonstrated as follows: Incubation of root hairs in situ with 3-azidonaphthalene-2,7-disulfonate – a strongly anionic, photoactivated fluorescent marker – followed by gel electrophoresis of membrane fractions showed the presence of root-hair specific proteins which, since the system was intact, suggests that they are on the outer surface of the cells. 相似文献
2.
Characterization of dimer subunits of intermediate filament proteins 总被引:16,自引:0,他引:16
R A Quinlan M Hatzfeld W W Franke A Lustig T Schulthess J Engel 《Journal of molecular biology》1986,192(2):337-349
The fundamental subunit of the various types of intermediate-sized filaments (IF) has been shown to be a tetramer that is thought to represent a double dimer, i.e. an array of two laterally packed coiled-coils of alpha-helices. The two-chain state of intact IF proteins had up to this point not been isolated and characterized as has been done for other fibrous alpha-helical coiled-coil proteins. Using buffers containing 3 M-guanidinium hydrochloride we prepared dimers by depolymerization of IF or by reconstitution from fully denatured molecules. Dimers of desmin (from chicken gizzard), vimentin (from bovine lens tissue and cultured human fibroblasts) and the neurofilament protein NF-L (from bovine brain) as well as in vitro formed homodimers of human and rat cytokeratins numbers 8 (A), 18 (D) and 19 ("40K"), are characterized by ultracentrifugation techniques (sedimentation velocity and equilibrium), electron microscopy and chemical cross-linking. The results show that IF proteins from discrete complexes of two polypeptide chains in parallel orientation and probably in coiled-coil configuration, which apparently have a high tendency to further associate into double dimers. Implications of these results for concepts of IF organization and IF protein assembly are discussed. 相似文献
3.
Rhizobium japonicum 61-A-101 and its bacteroids catabolize phenol and p-hydroxybenzoate. With phenol as a carbon source, utilization started only after a prolonged lag phase while p-hydroxybenzoate was almost instantancously metabolized. Succinate, which supports rapid growth of Rhizobium japonicum, completely repressed respication of phenol; the oxidation of p-hydroxybenzoate was partially inhibited. Pyruvate, supporting slower growth than succinate, retarded the onset of phenol consumption but did not affect its maximum rate.Catabolite repression of phenol utilization by succinate appears to be a characteristic feature of rhizobia. In Pseudomonas putida which also actively metabolizes phenol, succinate had no effect on phenol utilization. 相似文献
4.
Fibronectin (FN) turnover and turnover changes induced by the anticancer drug Adriamycin (ADR) were measured in human mesangial cells (HMC) in vitro. HMC cultures synthesize cellular FN (2.2+-0.3% of totalprotein synthesis; n = 12) which is secreted and incorporated into a fibrillar extracellular matrix (ECM). A 24 hr incubation of HMC with ADR (0.5–5 g/ml) resulted in an accumulation of FN in the culture medium, with a maximum increase following 5 pglml(7.3+-2.3pg/cell vs. controls: 4.4+-1.9pg/cell; n= 10). Correspondingly, radioactively labeled immunoprecipitable FN was increased in a dosage-dependent manner in the culture medium up to 50% vs. controls. The incorporation of radioactively labeled FN into ECM was significantly increased following 2 g ADR/ml. In accordance, immunofZuorescence staining revealed an expansion ofpericellular FNfibers in cultures exposed to 2 g ADR/ml. Concomitant with the accumulation of extracelhlar FN, radioactively labeled FN in the cells was reduced by 22%. Qualitative characterization of FN patterns revealed a diminished number of degradation products in the culture medium ofADR-treated HMC. These data suggest thatADR interferes with the turnover of FN secreted by HMC in vitro in such a way that FN accumulates extracellularly. This in turn leads to a reduced FN synthesis. These findings are compatible with a loss of urinary FN degradation products accompanying the onset ofproteinuria in ADR-treated rats.Abbreviations ADR
adriamycin
- BSA
bovine serum albumin
- DTT
dithiothreitol
- ECM
extracellular matrix
- EDTA
ethylenediamine tetraacetic acid disodium salt
- ELISA
enzyme-linked immunosorbent assay
- FCS
fetal calf serum
- FITC
fluorescein isothiocyanate
- FN
fibronectin
- HMC
human mesangial cell
- PBS
phosphate buffered saline
- PMSF
phenylmethylsulfonyl fluoride
- SDS
sodium dodecyl sulfate
- SDS-PAGE
SDS-polyacrylamide gel electrophoresis 相似文献
5.
Mechthild Geyer Tassilo Feuerer Guido Benno Feige 《Plant Systematics and Evolution》1984,145(1-2):41-54
The secondary lichen products of 31 specimens of theRhizocarpon superficiale group are examined by high performance liquid chromatography (HPLC). At 260 nm 13 different compounds have been detected. 6 of them are well-known lichen acids which occur in nearly all the species; but proportions are different and constant for each species. An analytical key is added.
Beitrag I einer Publikationsreihe. 相似文献
6.
7.
Cytokeratin domains involved in heterotypic complex formation determined by in-vitro binding assays 总被引:14,自引:0,他引:14
Cytokeratins are constituent proteins of intermediate filaments (IFs) that form heterotypic tetrameric IF subunits containing two polypeptide chains of each of the two cytokeratin subfamilies, i.e. the acidic (type I) and the basic (type II). To locate the molecular domains involved in the formation of these heterotypic complexes, we have developed a binding assay in which total cellular or cytoskeletal polypeptides, or proteolytically prepared cytokeratin fragments, are separated by one-, or two-dimensional gel electrophoresis, blot-transferred on to nitrocellulose paper and probed with radio-iodinated purified cytokeratin polypeptides or fragments thereof, using buffers of various ionic strengths with or without 4 M-urea. Using these polypeptides in the binding assay, specific heterotypic binding was observed between complementary cytokeratin polypeptides of the two subfamilies (but not with other IF proteins) and between the corresponding alpha-helical rod domain fragments. Both rod coils 1 and 2 of the type II cytokeratin 8 bound to the rod (coils 1 and 2) fragment of type I cytokeratins, and this binding occurred at both low and high ionic strengths. The results obtained indicate that: (1) the binding between cytokeratin polypeptides of the complementary type is stronger and more selective than interactions of cytokeratins with other IF and non-IF proteins; (2) both the head and the tail portions of the proteins are not required for heterotypic complex formation; (3) the complementarity information located in the alpha-helical portions of the rod domain, and in short sequences immediately flanking them, is sufficient to discriminate between the two types of cytokeratins and to secure the formation of heterotypic cytokeratin complexes; (4) both coils 1 and 2 of the rod can contribute to this association; and (5) the formation of the heterotypic cytokeratin complex is not critically dependent upon ionic interactions. Our results are further compatible with the concept that the heterotypic binding takes place between cytokeratin homodimer coiled-coils. 相似文献
8.
Renegar RH Chalovich JM Leinweber BD Zary JT Schroeter MM 《Histochemistry and cell biology》2009,131(2):191-196
This report compares cellular localization of fesselin in chicken smooth, skeletal and cardiac muscle tissues using affinity
purified polyclonal fesselin antibodies. Western blot analyses revealed large amounts of fesselin in gizzard smooth muscle
with lower amounts in skeletal and cardiac muscle. In gizzard, fesselin was detected by immunofluorescence as discrete cytoplasmic
structures. Fesselin did not co-localize with talin, vinculin or caveolin indicating that fesselin is not associated with
dense plaques or caveolar regions of the cell membrane. Immunoelectron microscopy established localization of fesselin within
dense bodies. Since dense bodies function as anchorage points for actin and desmin in smooth muscle cells, fesselin may be
involved in establishing cytoskeletal structure in this tissue. In skeletal muscle, fesselin was associated with desmin in
regularly spaced bands distributed along the length of muscle fibers suggesting localization to the Z-line. Infrequently,
this banding pattern was observed in heart tissue as well. Localization at the Z-line of skeletal and cardiac muscle suggests
a role in contraction of these tissues. 相似文献
9.
Ifey Alio Mirja Gudzuhn Pablo Pérez García Dominik Danso Marie Charlotte Schoelmerich Uwe Mamat Ulrich E. Schaible J?rg Steinmann Daniel Yero Isidre Gibert Thomas A. Kohl Stefan Niemann Matthias I. Gr?schel Johanna Haerdter Thomas Hackl Christel Vollstedt Mechthild B?meke Richard Egelkamp Rolf Daniel Anja Poehlein Wolfgang R. Streit 《Applied and environmental microbiology》2020,86(24)
10.
Nitrogen is an essential macronutrient for plant growth. Following uptake from the soil or assimilation within the plant, organic nitrogen compounds are transported between organelles, from cell to cell and over long distances in support of plant metabolism and development. These translocation processes require the function of integral membrane transporters. The review summarizes our current understanding of the molecular mechanisms of organic nitrogen transport processes, with a focus on amino acid, ureide and peptide transporters. 相似文献