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Marcos V. V. de Oliveira Xing Jin Xuan Chen Daniel Griffith Sai Batchu Hiroshi A. Maeda 《The Plant journal : for cell and molecular biology》2019,97(5):901-922
l ‐Tyrosine is an essential aromatic amino acid required for the synthesis of proteins and a diverse array of plant natural products; however, little is known on how the levels of tyrosine are controlled in planta and linked to overall growth and development. Most plants synthesize tyrosine by TyrA arogenate dehydrogenases, which are strongly feedback‐inhibited by tyrosine and encoded by TyrA1 and TyrA2 genes in Arabidopsis thaliana. While TyrA enzymes have been extensively characterized at biochemical levels, their in planta functions remain uncertain. Here we found that TyrA1 suppression reduces seed yield due to impaired anther dehiscence, whereas TyrA2 knockout leads to slow growth with reticulate leaves. The tyra2 mutant phenotypes were exacerbated by TyrA1 suppression and rescued by the expression of TyrA2, TyrA1 or tyrosine feeding. Low‐light conditions synchronized the tyra2 and wild‐type growth, and ameliorated the tyra2 leaf reticulation. After shifting to normal light, tyra2 transiently decreased tyrosine and subsequently increased aspartate before the appearance of the leaf phenotypes. Overexpression of the deregulated TyrA enzymes led to hyper‐accumulation of tyrosine, which was also accompanied by elevated aspartate and reticulate leaves. These results revealed that TyrA1 and TyrA2 have distinct and overlapping functions in flower and leaf development, respectively, and that imbalance of tyrosine, caused by altered TyrA activity and regulation, impacts growth and development of Arabidopsis. The findings provide critical bases for improving the production of tyrosine and its derived natural products, and further elucidating the coordinated metabolic and physiological processes to maintain tyrosine levels in plants. 相似文献
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Phenotypic and functional effects of heat shock protein 90 inhibition on dendritic cell 总被引:1,自引:0,他引:1
Bae J Mitsiades C Tai YT Bertheau R Shammas M Batchu RB Li C Catley L Prabhala R Anderson KC Munshi NC 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(12):7730-7737
The 90-kDa heat shock protein (Hsp90) plays an important role in conformational regulation of cellular proteins and thereby cellular signaling and function. As Hsp90 is considered a key component of immune function and its inhibition has become an important target for cancer therapy, we here evaluated the role of Hsp90 in human dendritic cell (DC) phenotype and function. Hsp90 inhibition significantly decreased cell surface expression of costimulatory (CD40, CD80, CD86), maturation (CD83), and MHC (HLA-A, B, C and HLA-DP, DQ, DR) markers in immature DC and mature DC and was associated with down-regulation of both RNA and intracellular protein expression. Importantly, Hsp90 inhibition significantly inhibited DC function. It decreased Ag uptake, processing, and presentation by immature DC, leading to reduced T cell proliferation in response to tetanus toxoid as a recall Ag. It also decreased the ability of mature DC to present Ag to T cells and secrete IL-12 as well as induce IFN-gamma secretion by allogeneic T cells. These data therefore demonstrate that Hsp90-mediated protein folding is required for DC function and, conversely, Hsp90 inhibition disrupts the DC function of significant relevance in the setting of clinical trials evaluating novel Hsp90 inhibitor therapy in cancer. 相似文献
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Polyana C Tizioto Jeremy F Taylor Jared E Decker Caio F Gromboni Mauricio A Mudadu Robert D Schnabel Luiz L Coutinho Gerson B Mour?o Priscila SN Oliveira Marcela M Souza James M Reecy Renata T Nassu Flavia A Bressani Patricia Tholon Tad S Sonstegard Mauricio M Alencar Rymer R Tullio Ana RA Nogueira Luciana CA Regitano 《遗传、选种与进化》2015,47(1)
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The aim of this study was to determine the first effect of lead on microbial activity in soil. The study was carried out in the soil samples from four different radish (Raphanus sativus L. var. radicula, Brassicaceae) fields along the highway in a district (Kadirli, Osmaniye) of the Eastern Mediterranean Region, Turkey. After the calculation of Pb contents, the Pb amounts of the soil samples were brought up to 50 and 100 mg Pb kg?1 by treatment with Pb(NO 3 ) 2 , and the samples for the carbon and the nitrogen mineralization were incubated under controlled conditions (28°C, constant moist). The carbon mineralization was determined by a CO 2 respiration method for 30 days. The nitrogen mineralization was observed in vitro for 6 weeks. The untreated group was statistically different from the 50 and 100 mg Pb kg?1 treatments in the aspect of the C(CO 2 ) outlet during mineralization (P ≤ 0.05), but difference between the 50 and 100 mg Pb kg?1 treatments was not significant. NH 4 -N and NO 3 -N contents of each soil were shown differences between across treatments. Based on these results, it is possible to conclude that the addition of 50 and 100 mg Pb kg?1 provided a toxic effect threshold for the microbial activity into 30 days. 相似文献
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Twelve fungi namelyAlternaria alternata, Aspergillus flavus, A niger, A ochraceus, Actinomucor repens, Capnodoium spp., Curvularia lunata, Fusarium
pallidoroseum, F solani, F verticillioides, Penicillium citrinum and Rhizopus stolonifer were recorded from samples ofAegle marmelos, Aesculus indica, Buchanania lanzan andPinus gerardiana. In case ofPrunus amygdalus only Rstolonifer was recorded. A significant variation in pattern of mycoflora incidence was observed in terms of source and season. Fungal
infestation in most of the substrates was found to be highest during monsoon. Aflatoxins were the most common mycotoxins elaborated
by different isolates ofA flavus obtained fromA marmelos, B lanzan andP gerardiana. The amount of aflatoxins produced by the toxigenic isolates ofA flavus was in the range of traces to 0.9–26.0 μg/ml inA marmelos, 0.8–17.5 μg/ml inP gerardiana and 0.65–13.2 μg/ml inB lanzan. The percentage toxigenicity was comparatively lower in the isolates of other mycotoxigenic fungi. Aflatoxins were detected
almost in all the samples analyzed for mycotoxin contamination. However, traces of zearalenone were detected inA marmelos. The concentration of aflatoxin B1 was in the range of 0.13–0.75 μg/g inA marmelos, 0.09–0.60 μg/g inP gerardiana and 0.01–0.20 ug/g inB lanzan. Mycotoxins were not detected inAesculus indica andPrunus amygdalus. 相似文献