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971.
Fluxes of carbohydrate metabolism in ripening bananas 总被引:1,自引:0,他引:1
The major fluxes of carbohydrate metabolism were estimated during starch breakdown by ripening bananas (Musa cavendishii Lamb ex Paxton). Hands of bananas, untreated with ethylene, were allowed to ripen in the dark at 21° C. Production of CO2 and the contents of starch, sucrose, glucose and fructose of intact fruit were determined for a period of 10 d that included the climacteric. The detailed distribution of label was determined after supplying the following to cores of pulp from climacteric fruit: [U-14C]-, [1-14C]-, [3,4-14C]-and [6-14C]glucose, [U-14C]glycerol, 14CO2. The data obtained were used to estimate the following fluxes, values given as mol hexose · (g FW)–1 · h–1 in parenthesis: starch to hexose monophosphates (5.9) and vice versa (0.4); hexose monophosphates to sucrose (7.7); sucrose to hexose (4.7); hexose to hexose monophosphate (3.8); glycolysis (0.5–1.6); triose phosphate to hexose monophosphates (0.14); oxidative pentose-phosphate pathway (0.48); CO2 fixation in the dark (0.005). These estimates are related to our understanding of carbohydrate metabolism during ripening.We both thank Mr Richard Trethewey for his constructive criticism: S.A.H. thanks the Managers of the Broodbank Fund for a fellowship. 相似文献
972.
Giang Ngan Khong Pratap Kumar Pati Frédérique Richaud Boris Parizot Przemyslaw Bidzinski Chung Duc Mai Martine Bès Isabelle Bourrié Donaldo Meynard Tom Beeckman Michael Gomez Selvaraj Ishitani Manabu Anna-Maria Genga Christophe Brugidou Vinh Nang Do Emmanuel Guiderdoni Jean-Benoit Morel Pascal Gantet 《Plant physiology》2015,169(4):2935-2949
973.
Séverin S Pollitt AY Navarro-Nuñez L Nash CA Mourão-Sá D Eble JA Senis YA Watson SP 《The Journal of biological chemistry》2011,286(6):4107-4116
The C-type lectin-like receptor CLEC-2 signals via phosphorylation of a single cytoplasmic YXXL sequence known as a hem-immunoreceptor tyrosine-based activation motif (hemITAM). In this study, we show that phosphorylation of CLEC-2 by the snake toxin rhodocytin is abolished in the absence of the tyrosine kinase Syk but is not altered in the absence of the major platelet Src family kinases, Fyn, Lyn, and Src, or the tyrosine phosphatase CD148, which regulates the basal activity of Src family kinases. Further, phosphorylation of CLEC-2 by rhodocytin is not altered in the presence of the Src family kinase inhibitor PP2, even though PLCγ2 phosphorylation and platelet activation are abolished. A similar dependence of phosphorylation of CLEC-2 on Syk is also seen in response to stimulation by an IgG mAb to CLEC-2, although interestingly CLEC-2 phosphorylation is also reduced in the absence of Lyn. These results provide the first definitive evidence that Syk mediates phosphorylation of the CLEC-2 hemITAM receptor with Src family kinases playing a critical role further downstream through the regulation of Syk and other effector proteins, providing a new paradigm in signaling by YXXL-containing receptors. 相似文献
974.
975.
Rositsa S. Milcheva Svetlozara L. Petkova Pavol Dubinsky Zuzana Hurniková Pavel Babál 《Biologia》2009,64(1):180-186
The in situ identification of carbohydrate structures in Trichinella spiralis intestinal larvae, adults and L1 muscular larvae was carried out by lectin histochemistry, with emphasis on the O-linked
glycans. The absence of reactivity with two lectins-TML and MAL indicated that Trichinella spiralis does not synthesize sialic acid. Reactivity with HPA, VVL-B4, PNA and UEA-I staining suggested that T. spiralis synthesizes and expresses on its cuticle O-linked glycans analogous to Tn-antigen (GalNAc-α-Ser/Thr), T-antigen (Gal-β1,3-GalNAc-α-Ser/Thr) and also structures analogous to A-blood group antigens (GalNAc-α1,3-Gal-β1,3(4)-(Fuc-α1,2-)-R). Expression of the saccharidic moieties is stage-specific. Blood group-A and T-antigen structures were identified
on the cuticle of the intestinal and muscular larvae. The Tn-antigen structure was missing in the intestinal larvae. Appropriate
ligands for WGA were not identified in the adult individuals. The obtained results may contribute to a better understanding
of the glycobiology of this parasitic nematode in relation to occupation of its intracellular niche. The presence of saccharidic
structures analogous to some of those expressed on the intestinal epithelial cells may serve as a protective shield on the
surface of the parasite. 相似文献
976.
977.
978.
W.Dennis Clark Lowell E. Urbatsch Ronald L. Hartman Richard A. Mayes Tom J. Mabry 《Biochemical Systematics and Ecology》1980,8(3):257-259
Complex flavonoid patterns are correlated with primitive woody taxa and high base chromosome numbers among Haplopappus segregates. Variability among flavonoid complements supports the polyphyletic interpretation of the genus. 相似文献
979.
We examined Cortisol (F) dynamics in female baboons treated with diethylstilbestrol (DES) or estradiol (E2) and compared values with those previously measured in nonpregnant and pregnant animals. Five regularly menstruating baboons (12–18 kg, BW) were administered 5 mg DES daily via fruit or 0.5 mg E2/0.1ml oil sc for 30 days. Blood samples, obtained before and after treatment, were assayed for serum F concentrations and serum Cortisol binding capacity (CBC). The metabolic clearance (MCR) and production rate (PR) of F and the catabolism of i.v. administered [3H] F were examined 25 and 30 days after initiation of estrogen treatment. Compared with values in nonpregnant baboons, F metabolism in estrogen treated animals is significantly altered and is characterized by increased formation of unconjugated metabolites, decreased glucuronylation, increased excretion of unconjugated F, cortisone, and highly polar metabolites, and increased CBC. These changes induced by estrogen are similar to those observed in intact pregnant baboons and permit the suggestion that the pattern of F metabolism and the level of CBC in baboon pregnancy are the result of elevated estrogen production.However, estrogen also caused a significant decrease in the MCR and PR of F, parameters which, by contrast, are similar in intact pregnant and nonpregnant baboons. These findings indicate that while estrogen also influences the rate of F clearance and F production, these effects of estrogen are not apparent during pregnancy. Collectively, these findings allow the suggestion that estrogen is a major factor which alters F metabolism and increases serum CBC in baboon gestation. However, additional factors are operative in primate pregnancy which maintain PR and MCR of F at levels similar to those of nonpregnant baboons. 相似文献
980.