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排序方式: 共有873条查询结果,搜索用时 15 毫秒
41.
42.
Willian Batista‐Silva David B. Medeiros Accio Rodrigues‐Salvador Danilo M. Daloso Rebeca P. Omena‐Garcia Franciele Santos Oliveira Lilian Ellen Pino Lzaro Eustquio Pereira Peres Adriano Nunes‐Nesi Alisdair R. Fernie Agustín Zsgn Wagner L. Araújo 《Plant, cell & environment》2019,42(2):448-465
Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher Vcmax and Jmax coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes. 相似文献
43.
Andrew E Rosselot Miri Park Mari Kim Toru MatsuUra Gang Wu Danilo E Flores Krithika R Subramanian Suengwon Lee Nambirajan Sundaram Taylor R Broda Heather A McCauley Jennifer A Hawkins Kashish Chetal Nathan Salomonis Noah F Shroyer Michael A Helmrath James M Wells John B Hogenesch Sean R Moore Christian I Hong 《The EMBO journal》2022,41(2)
44.
Yu P Di Prospero NA Sapko MT Cai T Chen A Melendez-Ferro M Du F Whetsell WO Guidetti P Schwarcz R Tagle DA 《Molecular and cellular biology》2004,24(16):6919-6930
Kynurenic acid (KYNA) can act as an endogenous modulator of excitatory neurotransmission and has been implicated in the pathogenesis of several neurological and psychiatric diseases. To evaluate its role in the brain, we disrupted the murine gene for kynurenine aminotransferase II (KAT II), the principal enzyme responsible for the synthesis of KYNA in the rat brain. mKat-2(-/-) mice showed no detectable KAT II mRNA or protein. Total brain KAT activity and KYNA levels were reduced during the first month but returned to normal levels thereafter. In contrast, liver KAT activity and KYNA levels in mKat-2(-/-) mice were decreased by >90% throughout life, though no hepatic abnormalities were observed histologically. KYNA-associated metabolites kynurenine, 3-hydroxykynurenine, and quinolinic acid were unchanged in the brain and liver of knockout mice. mKat-2(-/-) mice began to manifest hyperactivity and abnormal motor coordination at 2 weeks of age but were indistinguishable from wild type after 1 month of age. Golgi staining of cortical and striatal neurons revealed enlarged dendritic spines and a significant increase in spine density in 3-week-old mKat-2(-/-) mice but not in 2-month-old animals. Our results show that gene targeting of mKat-2 in mice leads to early and transitory decreases in brain KAT activity and KYNA levels with commensurate behavioral and neuropathological changes and suggest that compensatory changes or ontogenic expression of another isoform may account for the normalization of KYNA levels in the adult mKat-2(-/-) brain. 相似文献
45.
Production of L-ascorbic acid by metabolically engineered Saccharomyces cerevisiae and Zygosaccharomyces bailii 总被引:4,自引:0,他引:4
Yeasts do not possess an endogenous biochemical pathway for the synthesis of vitamin C. However, incubated with l-galactose, L-galactono-1,4-lactone, or L-gulono-1,4-lactone intermediates from the plant or animal pathway leading to l-ascorbic acid, Saccharomyces cerevisiae and Zygosaccharomyces bailii cells accumulate the vitamin intracellularly. Overexpression of the S. cerevisiae enzymes d-arabinose dehydrogenase and D-arabinono-1,4-lactone oxidase enhances this ability significantly. In fact, the respective recombinant yeast strains even gain the capability to accumulate the vitamin in the culture medium. An even better result is obtainable by expression of the plant enzyme L-galactose dehydrogenase from Arabidopsis thaliana. Budding yeast cells overexpressing the endogenous D-arabinono-1,4-lactone oxidase as well as L-galactose dehydrogenase are capable of producing about 100 mg of L-ascorbic acid liter(-1), converting 40% (wt/vol) of the starting compound L-galactose. 相似文献
46.
Locatelli C Pedrosa RC De Bem AF Creczynski-Pasa TB Cordova CA Wilhelm-Filho D 《Redox report : communications in free radical research》2004,9(2):89-95
Albendazole (ABZ) and mebendazole (MBZ) are two benzimidazole-derived drugs that show remarkable antihelmintic activity and are widely used in the treatment and control of helminths. Some antihelmintic drugs seem to act through the deleterious generation of reactive oxygen and nitrogen species (ROS and RNS, respectively) to which helminths have no, or relatively low, antioxidant defences (AD), when compared to aerobic organisms. The main objective of the present study consisted of the evaluation of the effect of both drugs on the AD and on some oxidative stress indicators in the host liver. Adult, male, Wistar rats were treated with ABZ or MBZ at doses of 40 mg/kg for different periods of time (2, 4, 8 and 10 days). After treatment, the activities of superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase, as well as the concentrations of TBARS, reduced glutathione, oxidized glutathione and total glutathione, were evaluated in rat hepatocytes. The serum nitrogen monoxide, usually known as nitric oxide (NO) levels, was also measured. The results showed that both drugs provoked an oxidative stress condition, demonstrated through the elevation of TBARS contents and through the decrease of some AD. Moreover, ABZ showed to be a strong ROS and RNS generator while MBZ showed a low and transient effect on ROS generation. It is suggested that MBZ could be the first-choice drug in the treatment of helminthiasis because it shares a similar therapeutic indication with ABZ, and because it causes only a mild oxidative stress to the host. 相似文献
47.
Nicholas?A.?DiProsperoEmail author Er-Yun?Chen Vinod?Charles Markus?Plomann Jeffrey?H.?Kordower Danilo?A.?Tagle 《Brain Cell Biology》2004,33(5):517-533
Huntington’s disease (HD) is caused by a polyglutamine repeat expansion in the N-terminus of the huntingtin protein. Huntingtin is normally present in the cytoplasm where it may interact with structural and synaptic elements. The mechanism of HD pathogenesis remains unknown but studies indicate a toxic gain-of-function possibly through aberrant protein interactions. To investigate whether early degenerative changes in HD involve alterations of cytoskeletal and vesicular components, we examined early cellular changes in the frontal cortex of HD presymptomatic (PS), early pathological grade (grade 1) and late-stage (grade 3 and 4) patients as compared to age-matched controls. Morphologic analysis using silver impregnation revealed a progressive decrease in neuronal fiber density and organization in pyramidal cell layers beginning in presymptomatic HD cases. Immunocytochemical analyses for the cytoskeletal markers α -tubulin, microtubule-associated protein 2, and phosphorylated neurofilament demonstrated a concomitant loss of staining in early grade cases. Immunoblotting for synaptic proteins revealed a reduction in complexin 2, which was marked in some grade 1 HD cases and significantly reduced in all late stage cases. Interestingly, we demonstrate that two synaptic proteins, dynamin and PACSIN 1, which were unchanged by immunoblotting, showed a striking loss by immunocytochemistry beginning in early stage HD tissue suggesting abnormal distribution of these proteins. We propose that mutant huntingtin affects proteins involved in synaptic function and cytoskeletal integrity before symptoms develop which may influence early disease onset and/or progression. 相似文献
48.
Campostrini N Pascali J Hamdan M Astner H Marimpietri D Pastorino F Ponzoni M Righetti PG 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,808(2):279-286
Neuroblastoma is the most common extracranial solid tumour of childhood and comprises up to 50% of malignancies among infants. There is a great need of designing novel therapeutic strategies and proteome analysis is one approach for defining markers useful for tumour diagnosis, as well as molecular targets for novel experimental therapies. We started by comparing healthy adrenal glands (which are the election organs developing primary neuroblastoma, NB, tumours) and adrenal glands carrying primary NB tumours, taken from nude mice. Standard maps of healthy and tumour samples were generated by analysis with the PDQuest software. The comparison between such maps showed up- and down-regulation of 84 polypeptide chains, out of a total of 700 spots detected by a fluorescent stain, Sypro Ruby. Spots that were differentially expressed between the two groups, were analysed by MALDI-TOF mass spectrometry and 14 of these spots were identified so far. Among these proteins, of particular interest are the down-regulated proteins adrenodoxin (21-folds), carbonic anhydrase III (eight-folds) and aldose reductase related protein I (eight-folds), as well as the up-regulated protein peptidyl-propyl cis-trans isomerase A (five-folds). Moreover new proteins, which were absent in control samples, were expressed in tumour samples, such as nucleophosmin (NPM) and stathmin (oncoprotein 18). 相似文献
49.
Dun W Chandra P Danilo P Rosen MR Boyden PA 《American journal of physiology. Heart and circulatory physiology》2003,285(4):H1378-H1384
Rapid atrial pacing causes electrical remodeling that leads to atrial fibrillation (AF). AF can further remodel atrial electrophysiology to maintain AF. Our previous studies showed that there was a marked difference in the duration of AF in dogs that have been atrial paced at 400 beats/min for 6 wk. We hypothesized that this difference is based on the changes in the degree of electrical remodeling caused by rapid atrial pacing versus that by AF. Right atrial cells were isolated from control dogs (Con, N = 28), from dogs with chronic AF (cAF dogs, N = 13, episodes lasting at least 6 days), or from dogs with nonsustained or brief episodes of AF (nAF dogs, N = 10, episodes lasting minutes to hours). Both transient outward (Ito) and sustained outward K+ current (Isus) densities/functions were determined using whole cell voltage-clamp techniques. In nAF cells, Ito density was reduced by 69% at +40 mV: from 7.1 +/- 0.5 pA/pF (Con, n = 59) to 2.2 +/- 0.2 pA/pF (nAF, n = 24) (P < 0.05). The voltage dependence of inactivation of Ito was shifted positively and decay kinetics were changed; however, recovery from inactivation was not altered in nAF cells. In contrast, Ito density in cAF cells was both significantly different from Con cells and larger than that in nAF cells [at +40 mV, 3.5 +/- 0.3 pA/pF (cAF, n = 29), P < 0.05]. In cAF cells, recovery from inactivation and decay of Ito were both slow; yet, voltage dependence inactivation of Ito approached that of Con cells. Furthermore, "recovered" Ito of cAF cells was more sensitive to tetraethylammonium than currents of Con and nAF cells. Isus densities of nAF and cAF cells did not differ. Both nAF and cAF cells have reduced Ito versus Con cells, but Ito remodeling of nAF cells differed from that of cAF cells. Ito in cAF dogs was likely remodeled by AF per se, whereas that in nAF dogs was likely the consequence of the rapid rate in the absence of sustained AF. 相似文献
50.
Segarra CI Casalongué CA Pinedo ML Ronchi VP Conde RD 《Journal of experimental botany》2003,54(386):1335-1341
A protein resistant to heat and proteolysis that inhibits serine proteases was isolated from wheat leaf apoplasts. Based on trypsin inhibition, its more active form was a 66-69 kDa oligomer. It was dissociated in an 18-21 kDa monomer having an amino terminal sequence identical to the Box A of germins and germin-like proteins. Like these proteins, it was glycosylated and showed manganese superoxide dismutase activity. The monomer displayed three forms when examined by 2D western blot: two of 19 kDa, pI 5.8 and 6.2; and one of 21 kDa, pI 5.8. It was found that the protein controls serine protease activity in the apoplast of plants challenged with the fungus Septoria tritici. 相似文献