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1.
The seed storage globulins from six Helianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species ( 11 and 22). The subunit corresponding to the 11 pair is present in H. petiolaris and in the three populations of H. annuus studied. The 2b2 pair is common to H. annuus and H. argophyllus. H. petiolaris presents two specific 2a2 and 44 pairs and H. annuus a specific 33 pair. In H. argophyllus 11 33 or 44 are never observed but are replaced by 13 and 31 pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations of H. annuus. Identity between the two H. petiolaris studied is also observed. H. annuus and H. argophyllus appear to be closer to each other than H. petiolaris concerning the seed storage globulins. 相似文献
2.
Although expression of the gastrin/cholecystokinin-2 receptor (CCK2R) is widely reported in human colorectal cancer, little is known on its role in mediating mature amidated gastrin (gastrin-17 amide, G-17) induced intracellular signal transduction in colon cancer cells. The purpose of this study was to explore the intracellular events of colorectal cancer cells after gastrin binding to CCK2R. Meanwhile, the influence of a natural point mutation 286V-->F in the third intracellular loop of CCK2R on gastrin-envoked intracellular signal transduction was also investigated. Firstly, Colo320 cells were stably transfected with wild type (Colo320 WT) and mutant CCK2R (Colo320 M), respectively. The intracellular signal transduction events in response to gastrin were investigated in both Colo320 WT and Colo320 M cells. In Colo320 WT cells, G-17 induced formation of intracellular cyclic AMP and inositol 1,4,5-trisphosphate, and stimulated intracellular calcium mobilization. G-17 also stimulated tyrosine phosphorylation of ERKl/2, p38, FAK, and paxillin, and up-regulated the mRNA expression of early response gene c-Jun and c-Fos. However, G-17 inhibited proliferation and induced apoptosis in Colo320 WT cells. Mutation 286V-->F in the third intracellular loop of CCK2R blocked G-17 induced biological without affecting binding affinity of CCK2R to G-17. Our results suggest that activation of CCK2R by gastrin stimulates heterotrimeric G-protein Gq and G(12/13) mediated intracellular signal transduction pathway in colon cancer cells. The valine-287 residue in third intracellular loop of CCK2R plays a pivotal role in CCK2R mediated intracellular signal transduction. 相似文献
3.
The HVA1 protein belongs to the LEA3 group, which is expressed during the late stage of seed maturation. It is also induced by exogenous abscisic acid (ABA) and a variety of environmental stresses in germinating barley ( Hordeum vulgare L.). In the present work, the potential role of HVA1 was investigated by studying its tissue distribution and subcellular localization in mature and stressed seeds by immuno-microscopic methods. In the mature seed, HVA1 protein was detected in all tissues except the non-living starchy endosperm. During germination the amount of HVA1 protein decreased but did not totally disappear. Incubation with 100 μM ABA, cold treatment or drought stress dramatically increased HVA1 expression in the germinated seed. In this work, the distribution of a LEA3 group protein was studied in a cereal seed for the first time by immuno-electron microscopy. In the scutellum and aleurone layer, HVA1 was localized both in the cytoplasm and protein storage vacuoles (PSVs). HVA1 protein was found to be threefold more abundant in PSVs than in the cytoplasm of an unstressed seed tissue. The ratio increased with ABA or stress treatments to at least ninefold. The role of HVA1 in PSVs remains unclear: a previously suggested possibility is ion sequestration to prevent precipitation during stress. On the other hand, HVA1 protein could also be degraded in PSVs. HVA1 protein does not have the signal peptide typical of proteins which are glycosylated and targeted into the vacuole via the Golgi complex. Because HVA1 is not glycosylated, it may use an alternative, ER-independent vacuolar pathway, also found in yeast cells. 相似文献
4.
55 accessions of wild peanuts ( Arachis spp.) introduced from South America were analyzed for seed storage protein composition using SDS-PAGE electrophoresis. The objectives of the study were to evaluate variability within sect. Arachis and to classify taxa based on protein composition. 25 different band positions were resolved. Individual accessions had 11 to 18 bands which included the conarachin region (MW > 50 kD), two to five bands in the acidic arachin region (MW 38–49.9 kD), three to seven in the intermediate MW region (23 to 37.9 kD), two to five bands in the basic arachin region (18–22.9 kD), and one to three bands in the low MW protein region (14–17.9 kD). These data were utilized in a principal coordinate analysis based on the matrix of genetic distances between all pairs of the 55 accessions. Several groups of accessions conformed to expected species classification including A. batizocoi, A. stenosperma, and A. monticola; while A. duranensis, A. cardenasii, A. helodes, and A. correntina did not form good groups. The study showed that great diversity exists for protein profiles and seed storage proteins have potential for aiding species classification and for serving as markers for interspecific hybridization studies. 相似文献
6.
The production of H 2O 2 in detached rice leaves of Taichung Native 1 (TN1) caused by CdCl 2 was investigated. CdCl 2 treatment resulted in H 2O 2 production in detached rice leaves. Diphenyleneiodonium chloride (DPI) and imidazole (IMD), inhibitors of NADPH oxidase (NOX),
prevented CdCl 2-induced H 2O 2 production, suggesting that NOX is a H 2O 2-genearating enzyme in CdCl 2-treated detached rice leaves. Phosphatidylinositol 3-kinase inhibitors wortmanin (WM) or LY294002 (LY) inhibited CdCl 2-inducted H 2O 2 production in detached rice leaves. Exogenous H 2O 2 reversed the inhibitory effect of WM or LY, suggesting that phosphatidylinositol 3-phosphate is required for Cd-induced H 2O 2 production in detached rice leaves. Nitric oxide donor sodium nitroprusside (SNP) was also effective in reducing CdCl 2-inducing accumulation of H 2O 2 in detached rice leaves. Cd toxicity was judged by the decrease in chlorophyll content. The results indicated that DPI, IMD,
WM, LY, and SNP were able to reduce Cd-induced toxicity of detached rice leaves. Twelve-day-old TN1 and Tainung 67 (TNG67)
rice seedlings were treated with or without CdCl 2. In terms of Cd toxicity (leaf chlorosis), it was observed that rice seedlings of cultivar TN1 are Cd-sensitive and those
of cultivar TNG67 are Cd-tolerant. On treatment with CdCl 2, H 2O 2 accumulated in the leaves of TN1 seedlings but not in the leaves of TNG67. Prior exposure of TN1 seedlings to 45 oC for 3 h resulted in a reduction of H 2O 2 accumulation, as well as Cd tolerance of TN1 seedlings treated with CdCl 2. The results strongly suggest that Cd toxicity of detached leaves and leaves attached to rice seedlings are due to H 2O 2 accumulation. 相似文献
7.
Summary Heterotrophic microorganisms are able to solubilize metals via excreted metabolites-most often di- or tricarboxylic acids but also amino acids. With amino acids Cu, Zn, Au, Ni, U, Hg and Sb have been solubilized from metal oxides, metal sulfides or elementary metals. In this work it was investigated if excreted amino acids play a role in the leaching of zinc from a zinc oxide containing industrial filter dust. Two bacteria- Pseudomonas putida and Corynebacterium glutamicum-and a fungus- Penicillium simplicissimum were used. P. putida and P. Simplicissimum have already been used to solubilize zinc oxide, whereas C. glutamicum was used because of its known ability to excrete amino acids. Amino acids in culture fluids were analyzed via derivatization with phenyl isothiocyanate, separation on a RP-18 column and UV-detection. All three microorganisms solubilized zinc from the filter dust and excreted much more citric acid than amino acids. Thus citric acid rather than amino acids was regarded to be the leaching agent. Of the two bacteria P. putida was more resistant towards the heavy metalcontaining filter dust. 相似文献
9.
We have established a sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of the activator protein which stimulates the enzymic hydrolysis of G M1 (G M1-activator) in human urine. The level of G M1-activator in 19 normal, adult urine samples was estimated to be 370.7±33.2 ng/ml. The amounts of G M1-activator excreted in 24 h were estimated to be between 0.28 and 1.1 mg. The coefficient of variation for this method is 4.3% for the intra-assay and 14.4% for the inter-assay. Urine samples, without purification, can be used directly for the ELISA. 相似文献
10.
C 2H 2 zinc-finger proteins play important roles in plant development including floral organogenesis, leaf initiation, lateral shoot initiation, gametogenesis and seed development. The gene for one such protein from Arabidopsis, AtZFP1 ( Arabidopsis thalianazinc-finger protein 1), is expressed at high levels in the shoot apex, including the apical meristem, developing leaves and the developing vascular system. In light-grown seedlings, AtZFP1 expression is induced about three days after germination, before the expansion of the true leaves. Dark-grown plants, in which photomorphogenesis is repressed, have no detectable AtZFP1 expression in the shoot apex. Under conditions which induce or mimic photomorphogenic development including growth in the light, shifting dark-grown plants to continuous light or growth on cytokinin in the dark, high levels of AtZFP1 expression are detected. Furthermore, AtZFP1 expression does not depend on active photosynthesis as shown by analysis of plants grown on the carotenoid biosynthetic inhibitor norflurazon. These results are discussed in relation to a possible role for AtZFP1 in shoot development, downstream of photomorphogenic activation. 相似文献
11.
Summary. Nodulins encoding repetitive proline-rich cell wall proteins (PRPs) are induced during early interactions with rhizobia, suggesting
a massive restructuring of the plant extracellular matrix during infection and nodulation. However, the proteins corresponding
to these gene products have not been isolated or characterized, nor have cell wall localizations been confirmed. Posttranslational
modifications, conformation, and interactions with other wall polymers are difficult to predict on the basis of only the deduced
amino acid sequence of PRPs. PsENOD2 is expressed in nodule parenchyma tissue during nodule organogenesis and encodes a protein with distinctive PRP motifs that
are rich in glutamate and basic amino acids. A database search for the ENOD2 signature motifs indicates that similar proteins
may have a limited phylogenetic distribution, as they are presently only known from legumes. To determine the ultrastructural
location of the proteins, antibodies were raised against unique motifs from the predicted ENOD2 sequence. The antibodies recognized
nodule-specific proteins in pea ( Pisum sativum), with a major band detected at 110 kDa, representing a subset of PRPs from nodules. The protein was detected specifically
in organelles of the secretory pathway and intercellular spaces in the nodule parenchyma, but it was not abundant in primary
walls. Similar proteins with an analogous distribution were detected in soybean ( Glycine max). The use of polyclonal antibodies raised against signature motifs of extracellular matrix proteins thus appears to be an
effective strategy to identify and isolate specific structural proteins for functional analysis.
Correspondence and reprints: Delaware Biotechnology Institute, Newark, DE 19711, U.S.A. 相似文献
12.
In isolated rat pancreatic acini, Src, RhoA, PI3-K, Vav-2, G(alpha12), and G(alpha13) were detected by immunoblotting. CCK enhanced the levels of these proteins, and the levels of Src and RhoA were reduced by the Src inhibitor herbimycin A and the Rho inhibitor pravastatin. The PI3-K inhibitor wortmannin reduced the level of PI3-K. These inhibitors also decreased amylase secretion in CCK-treated pancreatic acini without altering basal secretion. Immunoprecipitation studies indicated that CCK caused Src to associate with Vav-2, RhoA, and PI3-K and RhoA and Src to associate with Vav-2. Ras, RasGAP, and SOS did not coimmunoprecipitate with Vav-2, and RasGAP and SOS did not coimmunoprecipitate with RhoA. CCK also enhanced Vav-2 and RhoA to coimmunoprecipitate with G(alpha13). We conclude that CCK stimulates the recruitment of the Src-RhoA-PI3-K signaling pathway by Vav-2 downstream of G(alpha13) in pancreatic acini. 相似文献
13.
A major 27 kDa particulate and a minor 24 kDa cytosolic GTP-binding protein was detected in HEL cells upon incubation with [- 32P]GTP of nitrocellulose blots containing polypeptides separated using SDS-PAGE. Addition of lovastatin (30 M) to HEL cells in culture inhibited protein synthesis by 35%. However, this treatment resulted in a 5-fold increase, as quantitated by [- 32P]GTP binding, in the amount of cytosolic 24 kDa GTP-binding protein. Addition of cycloheximide plus lovastatin to cells in culture abolished the observed increase in 24 kDa GTP-binding protein. Incubation of cells with lovastatin plus [R,S]-[5- 3H]mevalonolactone resulted in the incorporation of radioactivity into several polypeptides in both the cytosolic and particulate fractions including a polypeptide of molecular mass of 24 kDa in the cytosol. The mobility of this 24 kDa isoprenylated protein on SDS-PAGE was identical to that of the GTP-binding protein increased in response to lovastatin. However, the 24 kDa protein remained in the cytosol after undergoing isoprenylation. The 24 kDa protein was distinct from the HEL cell, G25K/CDC42Hs GTP-binding protein and the GTP-binding protein that was a substrate for botulinum toxin C3 catalyzed ADP-ribosylation. Results demonstrate that lovastatin specifically increases the expression of a 24 kDa GTP-binding protein in HEL cells and that, isoprenylation of low molecular mass GTP-binding protein(s) may have function(s) in addition to its role in the targetting of these proteins to cell membrane. 相似文献
14.
The patterns of C. siliquastrum seed storage proteins (cercins) are described using SDS-polyacrylamide gel electrophoresis. The polypeptides detected had very different molecular weights (ranging from 168 to 34 KDa) which, together with their high homogeneity, produced a very good resolution of bands. These proteins could be ascribed to five different loci. The analysis of seed sets of individual trees indicated that the love tree is almost completely autogamous with less than 5% of outcrosses. Although this mode of reproduction seems to produce a decrease in heterozygote frequency among the seeds of the population analysed, the levels of variability detected were very high for an autogamous plant: all of the loci were polymorphic, with a mean heterozygosity of 0.327 and a polymorphic index of 0.412. Protein segregation revealed a strong genetic linkage between three cercin loci ( a, c and d) while the other two are independent. 相似文献
15.
Genetic polymorphism in the expression of the G M1(NeuGc) ganglioside has been shown in the liver of inbred strains of mice. Through analysis of the gangliosides of H-2 congenic and recombinant strains, this polymorphism was demonstrated to be controlled by a locus mapped left outside of the H-2 complex on chromosome 17, and the locus was assumed to control the level of the activity of G M1(NeuGc) synthetase, UDP-galactose:G M2(NeuGc) galactosyltransferase (E.C.2.4.1.62) [Hashimoto et al., J Biochem (1983) 94:2049-54].In the present study we analyzed the genetic linkage between the activity of the galactosyltransferase and the H-2 haplotype. For this purpose, we selected two inbred strains of mice, WHT/Ht and BALB/c, because they have different levels of the transferase activity and show different H-2 haplotypes; the specific activity of the transferase obtained with BALB/c was one-eighth of that with WHT/Ht, and BALB/c expressed the la.7 antigen as one of the products encoded in their H-2 d complex, whereas WHT/Ht did not. To analyze the linkage between these two phenotypes, WHT/Ht were mated with BALB/c to obtain the F 1 mice, and the female F 1 mice were then backcrossed to WHT/Ht. It was found that one half of the backcross generation expressed the la.7 antigen derived from BALB/c and had a significantly lower specific activity of the transferase than that of WHT/Ht, while the other half did not express the la.7 antigen but had the same specific activity of the transferase as that obtained with WHT/Ht.These results suggest that the locus controlling the level of the transferase activity in mouse liver is linked to the H-2 complex on chromosome 17.Abbreviations NeuGc
N-glycolylneuraminic acid
The ganglioside nomenclature is based on the system of Svennerholm, J Neurochem (1963) 10:613-23. The sialic acid species present is shown in parentheses after the ganglioside abbreviation. 相似文献
16.
Summary Genes coding for glutenin-like subunits and for several prolamin subunits with electrophoretic mobilities (lactate-PAGE) corresponding to those of omega- and gamma-gliadins of wheat were located in Dasypyrum villosum chromosome 1V. Genes controlling four gliadinlike subunits with electrophoretic mobilities corresponding to those of alpha- and gamma-gliadins were located on the short arm of chromosome 6V and on the long arm of chromosome 4V. N-terminal amino acid sequences of these four components were also determined and homology with alpha-type gliadins was demonstrated. The presence of genes coding for glutenin- and gliadin-like subunits on chromosomes 1V and 6V demonstrates homoeology between the D. villosum chromosomes 1V and 6V and the chromosomes of homoeologous groups 1 and 6 in wheat. It is likely that the additional locus Gli-V3 on chromosome 4V originated by translocation from the Gli-V2 locus. 相似文献
18.
Objectives: Extensive research has been dedicated to elucidating the mechanisms of signal transduction through different G protein-coupled receptors (GPCRs). However, relatively little is known about the regulation of receptor movement within the cell membrane upon ligand binding. In this study we focused our attention on the thyrotropin-releasing hormone (TRH) receptor that typically couples to G q/11 proteins. Methods: We monitored receptor diffusion in the plasma membrane of HEK293 cells stably expressing yellow fluorescent protein (YFP)-tagged TRH receptor (TRHR-YFP) by fluorescence recovery after photobleaching (FRAP). Results: FRAP analysis indicated that the lateral movement of the TRH receptor was markedly reduced upon TRH binding as the value of its diffusion coefficient fell down by 55%. This effect was prevented by the addition of the TRH receptor antagonist midazolam. We also found that siRNA-mediated knockdown of Gq/11α, Gβ, β-arrestin2 and phospholipase Cβ1, but not of Giα1, β-arrestin1 or G protein-coupled receptor kinase 2, resulted in a significant decrease in the rate of TRHR-YFP diffusion, indicating the involvement of the former proteins in the regulation of TRH receptor behavior. The observed partial reduction of the TRHR-YFP mobile fraction caused by down-regulation of Giα1 and β-arrestin1 suggests that these proteins may also play distinct roles in THR receptor-mediated signaling. Conclusion: These results demonstrate for the first time that not only agonist binding but also abundance of some signaling proteins may strongly affect TRH receptor dynamics in the plasma membrane. 相似文献
19.
Soaking the seeds of mungbean ( Vigna radiata L. Wilczek cv. K-851) in pyridoxine solution significantly enhanced leaf N, P and K concentrations at different growth stages,
and seed protein concentration at harvest. Leaf N, P and K were significantly correlated with root length and seed protein.
Thus, pyridoxine application not only enhanced the availability of nutrients to plants but also was responsible for the maintenance
of a favourable source-sink relationship, thus ensuring more nutritious seeds of mungbean. 相似文献
20.
Summary Total seed storage protein of the cultivated chickpea, C. arietinum L., and eight other wild annual Cicer species (all 2 n = 16) was separated and compared by sodium dodecyl sulphate polyacrylamide gel electrophoresis. The seed-protein profile was a conservative and species-specific trait. Relative interspecific similarities of protein patterns were estimated using Jaccard's similarity index, and a cluster analysis was performed. The resultant dendrogram generally agreed with the limited data already available on interspecific relationships in Cicer based on morphological characteristics, crossability, genome pairing in hybrids, karyotypes and isozyme analysis. The difference between the profiles of C. judaicum and C. pinnatifidum supported the idea that they are indeed two separate species. The closest relative of C. arietinum was C. reticulatum, followed by C. echinospermum and other species, while C. cuneatum was the farthest relative. In general, C. cuneatum was also genetically the farthest removed from any other species. The suggestion that C. reticulatum is the wild progenitor of the cultivated chickpea was therefore further supported. 相似文献
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