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21.
The ability of vacuoles prepared from V. faba leaves to convert 1-aminocyclopropane-1-carboxylic acid to C2H4 was destroyed when vacuoles were lysed by passage through a hypodermic needle, freezing and thawing, osmotic shock, treatment with ethanol or with a detergent. Ethylene synthesis in the vacuolar fraction was also inhibited by the uncouplers carbonyl cyanide m-chlorophenyl hydrazone and dinitrophenol and by the ionophores valinomycin, nigericin, and A23187. Ethylene formation increased with increasing pH of the incubation medium over the pH range of 5.0–7.5. These observations support the hypothesis that C2H4 biosynthesis in vacuolar preparations is dependent on membrane integrity, possibly because of the requirement for a transmembrane ion gradient.Abbreviations ACC
1-aminocyclopropane-1-carboxylic acid
- AVG
aminoethoxyvinylglycine
- CCCP
carbonyl cyanide m-chlorophenyl hydrazone 相似文献
22.
The use of monoclonal antibodies to fragments of chicken type IV collagen in structural and localization studies 总被引:6,自引:0,他引:6
R Mayne R D Sanderson H Wiedemann J M Fitch T F Linsenmayer 《The Journal of biological chemistry》1983,258(9):5794-5797
In previous experiments, three pepsin-resistant fragments of type IV collagen were isolated from chicken gizzards and designated 7S, F3, and (F1)2F2 (Mayne, R., and Zettergren, J. G. (1980) Biochemistry 19, 4065-4072). In the present experiments, a series of monoclonal antibodies to type IV collagen were prepared, each one of which recognized an epitope present in only one of the three fragments. A high molecular weight fraction of type IV collagen (designated 7S + arms (215 nm)) was isolated after agarose gel filtration and characterized by electron microscopy after rotary shadowing and by gel electrophoresis. Analysis of 7S + arms (215 nm) by inhibition enzyme-linked immunosorbent assay demonstrated the presence of the epitopes for 7S and F3 but not for (F1)2F2. This result, therefore, provides additional evidence that the order of the pepsin-resistant fragments of chicken type IV collagen is 7S-F3-(F1)2F2. 相似文献
23.
Mbikay M Croissandeau G Sirois F Anini Y Mayne J Seidah NG Chrétien M 《Developmental biology》2007,306(2):584-598
24.
The rate of exchange of peptide group NH hydrogens with the hydrogens of aqueous solvent is sensitive to neighboring side chains. To evaluate the effects of protein side chains, all 20 naturally occurring amino acids were studied using dipeptide models. Both inductive and steric blocking effects are apparent. The additivity of nearest-neighbor blocking and inductive effects was tested in oligo-and polypeptides and, suprisingly, confirmed. Reference rates for alanine-containing peptides were determined and effects of temperature considered. These results provide the information necessary to evaluate measured protein NH to ND exchange rates by comparing them with rates to be expected for the same amino acid sequence is unstructured aligo- and polypeptides. The application of this approach to protein studies is discussed. © 1993 Wiley-Liss, Inc. 相似文献
25.
Markus K Muellner Barbara Mair Yasir Ibrahim Claudia Kerzendorfer Hannelore Lechtermann Claudia Trefzer Freya Klepsch André C Müller Ernestine Leitner Sabine Macho‐Maschler Giulio Superti‐Furga Keiryn L Bennett José Baselga Uwe Rix Stefan Kubicek Jacques Colinge Violeta Serra Sebastian MB Nijman 《Molecular systems biology》2015,11(2)
26.
Kathleen?MB?VinetteEmail author Kathleen?M?Gibney Roy?Proujansky Paul?T?Fawcett 《BMC microbiology》2002,2(1):24
Background
We have previously reported that altered culture conditions (a broth media with shaking) could induce a strain of Helicobacter pylori to assume a long spiral morphology resembling that described for Helicobacter heilmannii. The present study was initiated to determine if other strains of H. pylori could be induced to assume that morphology and if doing so would alter the expression of immunodominant proteins. 相似文献27.
28.
The Synthesis of Collagen and Glycosaminoglycans by Dedifferentiated Chondroblasts in Culture 总被引:1,自引:0,他引:1
J. R. Schiltz R. Mayne H. Holtzer 《Differentiation; research in biological diversity》1973,1(2):97-108
Marked changes occur in the morphology of chick chondroblasts grown for 5 days in F-10 medium containing either 5-bromo-2'-deoxyuridine or embryo extract. The cells lose the characteristic polygonal morphology and assume a flattened 'fibroblastic' appearance. To determine whether the morphological changes reflect a biochemical transformation toward frank fibroblasts, changes in collagen and glycosaminoglycan synthesis were examined in these 'dedifferentiated' cells. Growth in either medium did not significantly affect the total amount of collagen synthesized. However, the subunit composition of the collagen chains was different. Freshly isolated cartilage trunks or control chondroblast cultures synthesized only α1 subunits (suggesting exclusive synthesis of α1(ll)3 -type collagen), whereas dedifferentiated cultures synthesized both α1 and, in addition, some α2 subunits (suggesting synthesis of fibroblasttype α1(l)2 α2-type collagen). Incorporation of labelled glucosamine in F-10 medium showed that the major glycosaminoglycan synthesized by either cartilage trunks or chondroblast monolayers is chondroitin sulphate; little, if any, hyaluronic acid could be detected. With growth in embryo extract (EE) glucosamine was incorporated equally into chondroitin sulphate and hyaluronic acid, whereas in BUdR, chondroitin sulphate synthesis was completely inhibited. Distinct biochemical differences were therefore found for both collagen and glycosaminoglycan synthesis during growth in either BUdR or EE. Such changes were not identical but both demonstrate changes in synthetic programme tending to approach that of frank fibroblasts. 相似文献
29.
NARC-1/PCSK9 and its natural mutants: zymogen cleavage and effects on the low density lipoprotein (LDL) receptor and LDL cholesterol 总被引:1,自引:0,他引:1
Benjannet S Rhainds D Essalmani R Mayne J Wickham L Jin W Asselin MC Hamelin J Varret M Allard D Trillard M Abifadel M Tebon A Attie AD Rader DJ Boileau C Brissette L Chrétien M Prat A Seidah NG 《The Journal of biological chemistry》2004,279(47):48865-48875
The discovery of autosomal dominant hypercholesterolemic patients with mutations in the PCSK9 gene, encoding the proprotein convertase NARC-1, resulting in the missense mutations suggested a role in low density lipoprotein (LDL) metabolism. We show that the endoplasmic reticulum-localized proNARC-1 to NARC-1 zymogen conversion is Ca2+-independent and that within the zymogen autocatalytic processing site SSVFAQ [downward arrow]SIP Val at P4 and Pro at P3' are critical. The S127R and D374Y mutations result in approximately 50-60% and > or =98% decrease in zymogen processing, respectively. In contrast, the double [D374Y + N157K], F216L, and R218S natural mutants resulted in normal zymogen processing. The cell surface LDL receptor (LDLR) levels are reduced by 35% in lymphoblasts of S127R patients. The LDLR levels are also reduced in stable HepG2 cells overexpressing NARC-1 or its natural mutant S127R, and this reduction is abrogated in the presence of 5 mm ammonium chloride, suggesting that overexpression of NARC-1 increases the turnover rate of the LDLR. Adenoviral expression of wild type human NARC-1 in mice resulted in a maximal approximately 9-fold increase in circulating LDL cholesterol, while in LDLR-/- mice a delayed approximately 2-fold increase in LDL cholesterol was observed. In conclusion, NARC-1 seems to affect both the level of LDLR and that of circulating apoB-containing lipoproteins in an LDLR-dependent and -independent fashion. 相似文献
30.
Gibson TM Brennan P Han S Karami S Zaridze D Janout V Kollarova H Bencko V Navratilova M Szeszenia-Dabrowska N Mates D Slamova A Pfeiffer RM Stolzenberg-Solomon RZ Mayne ST Yeager M Chanock S Rothman N Chow WH Rosenberg PS Boffetta P Moore LE 《PloS one》2011,6(10):e26165