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蚕豆叶片发育与衰老过程中超氧物歧化酶活性与丙二醛含量变化 总被引:2,自引:0,他引:2
蚕豆植株叶片随茎节自上而下表现出明显的发育与衰老顺序,可作为衰老特征的是叶绿素和蛋白质含量明显下降。蚕豆叶中SOD活性主要定位于12 000× g离心后所得的上清液和叶绿体组分。衰老叶片的SOD总活性和叶绿体组分的相对活性都有所下降,SOD同工酶谱也发生了改变。O_2~ 产生速率随叶龄增大而稍上升;而MDA含量在叶片外观表现枯黄衰老征兆前就急剧上升。可能因为衰老叶片过氧化氢酶活性大幅度下降与SOD之间的不平衡,致使O_2~ 代谢中间产物累积而引起膜的损伤. 相似文献
3.
A. M. Bajo L. G. Guijarro M. G. Juarranz P. Valenzuela P. Martinez J. C. Prieto 《Bioscience reports》1993,13(2):69-77
Vasoactive intestinal peptide (VIP) has been shown to stimulate adenylyl cyclase activity in human endometrial membranes. The effect was dependent on the time and temperature of incubation as well as on the concentration of endometrial membrane proteins in the medium. In the presence of 1 M GTP, half-maximal stimulation of adenylyl cyclase activity was observed at 25.0±7.0 nM VIP, whereas the maximal activity (at 1 M VIP)corresponded to an increase of about 140% with respect to basal values (7.5±0.6 pmol cyclic AMP/min/mg of protein). However, the maximal stimulation of adenylyl cyclase activity was obtained with helodermin (1 M) that increased the activity by 170% over the basal. The relative potency of VIP-related peptides upon the adenylyl cyclase activity was: helodermin (ED50=1.8±1.4 nM)>VIP(ED50=25.0±7.0 nM)>PHI (ED50=725.0±127.2 nM). Secretin had a faint effect upon the adenylyl cyclase activity and glucagon was completely inefficient at this level. The presence of s and i subunits of G proteins in human endometrium was detected by immunoblot. Preliminary results showed the presence of two classes of125I-VIP receptors in human endometrial membranes with the following stoichoimetric parameters: high affinity receptor (Kd=2.0 nM, binding capacity 0.1 pmol VIP/mg protein) and low affinity receptor (Kd=0.43 M, binding capacity 13.1 pmol VIP/mg protein). The present results together with the known presence of VIP in human uterus and the actions of this neuropeptide in the adjacent myometrial tissue support the idea that VIP and related peptides may have a role in human endometrium. 相似文献
4.
Biosynthesis of lysosomal hydrolases: their synthesis in bound polysomes and the role of co- and post-translational processing in determining their subcellular distribution 总被引:37,自引:20,他引:17
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By in vitro translation of mRNA’s isolated from free and membrane-bound polysomes, direct evidence was obtained for the synthesis of two lysosomal hydrolases, β-glucuronidase of the rat preputial gland and cathespin D of mouse spleen, on polysomes bound to rough endoplasmic reticulum (ER) membranes. When the mRNA’s for these two proteins were translated in the presence of microsomal membranes, the in vitro synthesized polypeptides were cotranslationally glycosylated and transferred into the microsomal lumen. Polypeptides synthesized in the absence of microsomal membranes were approximately 2,000 daltons larger than the respective unglycosylated microsomal polypeptides found after short times of labeling in cultured rat liver cells treated with tunicamycin. This strongly suggests that nascent chains of the lysosomal enzymes bear transient amino terminal signals which determine synthesis on bound polysomes and are removed during the cotranslational insertion of the polypeptides into the ER membranes. In the line of cultured rat liver cells used for this work, newly synthesized lysosomal hydrolases showed a dual destination; approximately 60 percent of the microsomal polypeptides detected after short times of labeling were subsequently processed proteolytically to lower molecular weight forms characteristic of the mature enzymes. The remainder was secreted from the cells without further proteolytic processing. As previously observed by other investigations in cultured fibroblasts (A. Gonzalez-Noriega, J.H. Grubbs, V. Talkad, and W.S. Sly, 1980, J Cell Biol. 85: 839-852; A. Hasilik and E.F. Neufeld, 1980, J. Biol. Chem., 255:4937-4945.) the lysosomotropic amine chloroquine prevented the proteolytic maturation of newly synthesized hydrolases and enhanced their section. In addition, unglycosylated hydrolases synthesized in cells treated with tunicamycin were exclusively exported from the cells without undergoing proteolytic processing. These results support the notions that modified sugar residues serve as sorting out signals which address the hydrolases to their lysosomal destination and that final proteolytic cleavage of hydrolase precursors take place within lysosome itself. Structural differences in the carbohydrate chains of intracellular and secreted precursors of cathespin D were detected from their differential sensitivity to digestion with endoglycosidases H and D. These observations suggest that the hydrolases exported into the medium follow the normal secretory route and that some of their oligosaccharides are subject to modifications known to affect many secretory glycoproteins during their passage through the Golgi apparatus. 相似文献
5.
Selene Pérez‐García Mar Carrión Irene Gutiérrez‐Cañas Isidoro González‐Álvaro Yasmina Juarranz 《Journal of cellular and molecular medicine》2016,20(4):678-687
ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family is known to play an important role in the pathogenesis of osteoarthritis (OA), working on aggrecan degradation or altering the integrity of extracellular matrix (ECM). Thus, the main purpose of our study was to define the role of vasoactive intestinal peptide (VIP) and corticotrophin‐releasing factor (CRF), as immunoregulatory neuropeptides, on ADAMTS production in synovial fibroblasts (SF) from OA patients and healthy donors (HD). OA‐ and HD‐SF were stimulated with pro‐inflammatory mediators and treated with VIP or CRF. Both neuropeptides decreased ADAMTS‐4, ‐5, ‐7 and ‐12 expressions, aggrecanase activity, glycosaminoglycans (GAG), and cartilage oligomeric matrix protein (COMP) degradation after stimulation with fibronectin fragments (Fn‐fs) in OA‐SF. After stimulation with interleukin‐1β, VIP reduced ADAMTS‐4 and ‐5, and both neuropeptides decreased ADAMTS‐7 production and COMP degradation. Moreover, VIP and CRF reduced Runx2 and β‐catenin activation in OA‐SF. Our data suggest that the role of VIP and CRF on ADAMTS expression and cartilage degradation could be related to the OA pathology since scarce effects were produced in HD‐SF. In addition, their effects might be greater when a degradation loop has been established, given that they were higher after stimulation with Fn‐fs. Our results point to novel OA therapies based on the use of neuropeptides, since VIP and CRF are able to stop the first critical step, the loss of cartilage aggrecan and the ECM destabilization during joint degradation. 相似文献
6.
Phylogenetic relationships were determined for 76 partial P-element
sequences from 14 species of the melanogaster species group within the
Drosophila subgenus Sophophora. These results are examined in the context
of the phylogeny of the species from which the sequences were isolated.
Sequences from the P-element family fall into distinct subfamilies, or
clades, which are often characteristic for particular species subgroups.
When examined locally among closely related species, the evolution of P
elements is characterized by vertical transmission, whereby the P-element
phylogeny traces the species phylogeny. On a broader scale, however, the
P-element phylogeny is not congruent with the species phylogeny. One
feature of P-element evolution in the melanogaster group is the presence of
more than one P-element subfamily, differing by as much as 36%, in the
genomes of some species. Thus, P elements from several individual species
are not monophyletic, and a likely explanation for the incongruence between
P-element and species phylogenies is provided by the comparison of
paralogous sequences. In certain instances, horizontal transfer seems to be
a valid alternative explanation for lack of congruence between species and
P-element phylogenies. The canonical P-element subfamily, which represents
the active, autonomous transposable element, is restricted to D.
melanogaster. Thus, its origin clearly lies outside of the melanogaster
species group, consistent with the earlier conclusion of recent horizontal
transfer.
相似文献
7.
Jose MG Vilar 《BMC systems biology》2010,4(1):152
Background
Cellular responses to death-promoting stimuli typically proceed through a differentiated multistage process, involving a lag phase, extensive death, and potential adaptation. Deregulation of this chain of events is at the root of many diseases. Improper adaptation is particularly important because it allows cell sub-populations to survive even in the continuous presence of death conditions, which results, among others, in the eventual failure of many targeted anticancer therapies. 相似文献8.
Gomariz RP Arranz A Juarranz Y Gutierrez-Cañas I Garcia-Gomez M Leceta J Martínez C 《Peptides》2007,28(9):1825-1832
The contribution of VIP immune functions to the regulation of homeostasis and health is well known. Modulation of immune responses through new therapeutics is one of the main goals of physicians and scientists seeking to control inflammatory/autoimmune diseases in humans. Initial therapeutic strategies targeted adaptive immune responses; discovery of Toll-like receptors (TLR) has widened the horizon to include targeting the innate immune system. In this review we have summarized recent information about VIP modulation of TLR function, and we suggest that VIP represents a new therapeutic option in the management of several pathologies. 相似文献
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10.
Alessandro S Guimarães Filipe B Carmo Marcos B Heinemann Ricardo WD Portela Roberto Meyer Andrey P Lage Núbia Seyffert Anderson Miyoshi Vasco Azevedo Aurora MG Gouveia 《BMC veterinary research》2011,7(1):1-5