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991.
Nagamine A Matsusaka H Ushijima T Kawagoe Y Ogawa M Okita TW Kumamaru T 《Plant & cell physiology》2011,52(6):1003-1016
The rice prolamins consist of cysteine-rich 10 kDa (CysR10), 14 kDa (CysR14) and 16 kDa (CysR16) molecular species and a cysteine-poor 13 kDa (CysP13) polypeptide. These storage proteins form protein bodies (PBs) composed of single spherical intracisternal inclusions assembled within the lumen of the rough endoplasmic reticulum. Immunofluorescence and immunoelectron microscopy demonstrated that CysR10 and CysP13 were asymmetrically distributed within the PBs, with the former concentrated at the electron-dense center core region and the latter distributed mainly to the electron-lucent peripheral region. These results together with temporal expression data showed that the formation of prolamin-containing PB-I in the wild-type endosperm was initiated by the accumulation of CysR10 to form the center core. In mutants deficient for cysteine-rich prolamins, the typical PB-I structures containing the electron-dense center core were not observed, and instead were replaced by irregularly shaped, electron-lucent, hypertrophied PBs. Similar, deformed PBs were observed in a CysR10 RNA interference plant line. These results suggest that CysR10, through its formation of the central core and its possible interaction with other cysteine-rich prolamins, is required for tight packaging of the proteins into a compact spherical structure. 相似文献
992.
Li P Fan W Xu J Lu M Yamamoto H Auwerx J Sears DD Talukdar S Oh D Chen A Bandyopadhyay G Scadeng M Ofrecio JM Nalbandian S Olefsky JM 《Cell》2011,147(4):815-826
Insulin resistance, tissue inflammation, and adipose tissue dysfunction are features of obesity and Type 2 diabetes. We generated adipocyte-specific Nuclear Receptor Corepressor (NCoR) knockout (AKO) mice to investigate the function of NCoR in adipocyte biology, glucose and insulin homeostasis. Despite increased obesity, glucose tolerance was improved in AKO mice, and clamp studies demonstrated enhanced insulin sensitivity in liver, muscle, and fat. Adipose tissue macrophage infiltration and inflammation were also decreased. PPARγ response genes were upregulated in adipose tissue from AKO mice and CDK5-mediated PPARγ ser-273 phosphorylation was reduced, creating a constitutively active PPARγ state. This identifies NCoR as an adaptor protein that enhances the ability of CDK5 to associate with and phosphorylate PPARγ. The dominant function of adipocyte NCoR is to transrepress PPARγ and promote PPARγ ser-273 phosphorylation, such that NCoR deletion leads to adipogenesis, reduced inflammation, and enhanced systemic insulin sensitivity, phenocopying the TZD-treated state. 相似文献
993.
Ai Zhen Zhilong Bie Yuan Huang Zhixiong Liu Bo Lei 《Acta Physiologiae Plantarum》2011,33(6):2311-2319
Plant growth, photosynthetic parameters, chloroplast ultrastructure, and the ascorbate-glutathione cycle system in chloroplasts
of self-grafted and rootstock-grafted cucumber leaves were investigated. Grafted plants were grown hydroponically and were
exposed to 0, 50, and 100 mM NaCl concentrations for 10 days. Under NaCl stress, the hydrogen peroxide (H2O2) content in cucumber chloroplasts increased, the chloroplast ultrastructure was damaged, and the gas stomatal conductance,
intercellular CO2 concentration, as well as shoot dry weight, plant height, stem diameter, leaf area, and leaf relative water content were
inhibited, whereas these changes were less severe in rootstock-grafted plants. The activities of ascorbate peroxidase (APX;
EC 1.11.1.11), glutathione reductase (GR; EC 1.6.4.2), and dehydroascorbate reductase (DHAR EC 1.8.5.1) were higher in the
chloroplasts of rootstock-grafted plants compared with those of self-grafted plants under 50 and 100 mM NaCl. Similar trends
were shown in leaf net CO2 assimilation rate and transpiration rate, as well as reduced glutathione content under 100 mM NaCl. Results suggest that
rootstock grafting enhances the H2O2-scavenging capacity of the ascorbate–glutathione cycle in cucumber chloroplasts under NaCl stress, thereby protecting the
chloroplast structure and improving the photosynthetic performance of cucumber leaves. As a result, cucumber growth is promoted. 相似文献
994.
Mitra Saffarian Tousi Ahmad Reza Bahrami Jafar Zolala Maryam M. Matin 《Acta Physiologiae Plantarum》2011,33(2):469-472
CEL I enzyme from celery, as a member of S1 family of nucleases, is known for its high specific activity in recognition and
cleavage of base-substitution mismatches on heteroduplex DNA molecules. Despite valuable applications of the enzyme in mutation
screening studies, little is known about its function at cellular level. In the present study, we investigated the pattern
of CEL I expression in ethyl methanesulfonate (EMS) treated celery plants. An abnormal growth pattern along with wide and
clear lesions were observed on the treated plants. A considerable increase in the level of CEL I protein happened in vegetative
and generative parts of EMS-treated plants compared with controls. Despite such induction, the enzyme is not expected to be
involved in DNA repair during EMS treatment due to the absence of any known nuclear localization signal in the deduced sequence
of CEL I protein. Considering the fact that CEL I orthologs are induced during programmed cell death, the high expression
of CEL I upon EMS treatment could be due to the stress and necrotic cell death created by the treatment. 相似文献
995.
A truncated alkaline β-mannanase from alkaliphilic Bacillus sp. N16-5 (MAN330) was expressed and secreted in Kluyveromyces cicerisporus. The recombinant engineered strain for MAN330 production was stable during 80 generations, and the maximum yield of MAN330 reached 3,795 U/ml in 15 l fermenter. MAN330 exhibited similar pH optima, temperature optima, and substrate specificities to its full-length protein (MAN493). However, stability of MAN330 was about 7% higher than that of MAN493 from pH 9-11. MAN330 had about 10% higher stability than MAN493 from 60°C to 80°C. 相似文献
996.
The interaction between cuprous oxide (Cu(2)O) nanocubes and bovine serum albumin (BSA) was investigated from a spectroscopic angle under simulative physiological conditions. Under pH 7.4, Cu(2)O could effectively quench the intrinsic fluorescence of BSA via static quenching. The apparent binding constant (K(A)) was 3.23, 1.91, and 1.20?×?10(4) M(-1) at 298, 304, and 310 K, respectively, and the number of binding sites was 1.05. According to the Van't Hoff equation, the thermodynamic parameters (ΔH° = -63.39 kJ mol(-1), ΔS° = -126.45 J?mol(-1) K(-1)) indicated that hydrogen bonds and van der Waals forces played a major role in stabilizing the BSA-Cu(2)O complex. Besides, the average binding distance (r(0)?= 2.76 nm) and the critical energy transfer distance (R(0) = 2.35 nm) between Cu(2)O and BSA were also evaluated according to F?rster's non-radioactive energy transfer theory. Furthermore, UV-visible and circular dichroism results showed that the addition of Cu(2)O changed the secondary structure of BSA and led to a decrease in α-helix. All results showed that BSA underwent substantial conformational changes induced by Cu(2)O, which can be very helpful in the study of nanomaterials in the application of biomaterials. 相似文献
997.
998.
Xiao‐Wei Fei Yan‐Jia Fang Jia‐Li Zhuang Yan‐Ai Mei 《Journal of cellular physiology》2011,226(2):440-449
Brain natriuretic peptide (BNP) may act as a neuromodulator via its associated receptors (natriuretic peptide receptors, NPRs) in the central nervous system (CNS), but few studies have reported its activity in the peripheral nervous system (PNS). In this study, we observed that BNP increased the tetraethylammonium chloride (TEA)‐sensitive delayed rectifier outward potassium current (IK) in mouse Schwann cells (SCs) using whole‐cell recording techniques. At concentrations of 1–100 nM, BNP reversibly activated IK in a dose‐dependent manner, with modulating its steady‐state activation and inactivation properties. The effect of BNP on IK was abolished by preincubation with the specific antagonist of NPR‐A, and could not be mimicked by application of NPR‐C agonist. These results were supported by immunocytochemical findings indicating that NPR‐A was expressed in SCs. The application of 8‐Br‐guanosine 3′,5′‐monophosphate (8‐Br‐cGMP) mimicked the effect of BNP on IK, but BNP was unable to further increase IK after the application of cyclic guanosine monophosphate (cGMP). Genistein blocked IK and also completely eliminated the effects of BNP and cGMP on IK. The selective KV2.1 subunit blocker, Jingzhaotoxin‐III (JZTX‐III), reduced IK amplitude by 30%, but did not abolish the increase effect of BNP on IK amplitude. In addition, BNP significantly stimulated SCs proliferation and this effect could be partly inhibited by TEA. Together these results suggest that BNP modulated IK probably via cGMP‐ and tyrosine kinase‐dependent pathways by activation of NPR‐A. This effect of BNP on IK in SCs might partly explain its effect on cell proliferation. J. Cell. Physiol. 226: 440–449, 2011. © 2010 Wiley‐Liss, Inc. 相似文献
999.
NADPH-dependent reductases involved in the detoxification of reactive carbonyls in plants 总被引:1,自引:0,他引:1
Yamauchi Y Hasegawa A Taninaka A Mizutani M Sugimoto Y 《The Journal of biological chemistry》2011,286(9):6999-7009
Reactive carbonyls, especially α,β-unsaturated carbonyls produced through lipid peroxidation, damage biomolecules such as proteins and nucleotides; elimination of these carbonyls is therefore essential for maintaining cellular homeostasis. In this study, we focused on an NADPH-dependent detoxification of reactive carbonyls in plants and explored the enzyme system involved in this detoxification process. Using acrolein (CH(2) = CHCHO) as a model α,β-unsaturated carbonyl, we purified a predominant NADPH-dependent acrolein-reducing enzyme from cucumber leaves, and we identified the enzyme as an alkenal/one oxidoreductase (AOR) catalyzing reduction of an α,β-unsaturated bond. Cloning of cDNA encoding AORs revealed that cucumber contains two distinct AORs, chloroplastic AOR and cytosolic AOR. Homologs of cucumber AORs were found among various plant species, including Arabidopsis, and we confirmed that a homolog of Arabidopsis (At1g23740) also had AOR activity. Phylogenetic analysis showed that these AORs belong to a novel class of AORs. They preferentially reduced α,β-unsaturated ketones rather than α,β-unsaturated aldehydes. Furthermore, we selected candidates of other classes of enzymes involved in NADPH-dependent reduction of carbonyls based on the bioinformatic information, and we found that an aldo-keto reductase (At2g37770) and aldehyde reductases (At1g54870 and At3g04000) were implicated in the reduction of an aldehyde group of saturated aldehydes and methylglyoxal as well as α,β-unsaturated aldehydes in chloroplasts. These results suggest that different classes of NADPH-dependent reductases cooperatively contribute to the detoxification of reactive carbonyls. 相似文献
1000.