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Illumination of a suspension of thylakoids with light at high intensity causes inhibition of the photosystem II electron transport activity and loss from the membrane of the D1 protein of the photosystem II reaction center. Impairment of the electron transport activity and depletion of D1 protein from the thylakoid membrane of pea were investigated with reference to the presence or absence of oxygen in the suspension. The breakdown products of the D1 protein were identified by immunoblotting with anti-D1 polyclonal antibodies which were proven to recognize mainly the C-terminal region of the protein. The results obtained show that (i) the light-induced inactivation of the photosystem II electron transport activity under anaerobic conditions is faster than in the presence of oxygen; (ii) depletion of D1 protein is observed on a longer time scale with respect to loss of electron transport activity and is faster when photoinhibition is performed in the presence of oxygen; (iii) C-terminal fragments of D1 are only observed when photoinhibition is carried out anaerobically and are mainly localized in the stroma-exposed regions; and (iv) the fragments observed after anaerobic photoinhibition are quickly degraded on further illumination of the thylakoid suspension in the presence of oxygen. 相似文献
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Hermann-Georg Holzhütter Johan Friso Lock Pouria Taheri Sascha Bulik Andrean Goede Martin Stockmann 《PloS one》2013,8(8)
Breath tests based on the administration of a 13C-labeled drug and subsequent monitoring of 13CO2 in the breath (quantified as DOB – delta over baseline) liberated from the drug during hepatic CPY-dependent detoxification are important tools in liver function diagnostics. The capability of such breath tests to reliably indicate hepatic CYP performance is limited by the fact that 13CO2 is not exclusively exhaled but also exchanged with other compartments of the body. In order to assess this bias caused by variations of individual systemic CO2 kinetics we administered intravenously the test drug 13C-methacetin to 25 clinically liver-healthy individuals and monitored progress curves of DOB and the plasma concentration of 13C-methacetin. Applying compartment modelling we estimated for each individual a set of kinetic parameters characterizing the time-dependent exchange of the drug and of CO2 with the liver and non-hepatic body compartments. This analysis revealed that individual variations in the kinetics of CO2 may account for up to 30% deviation of DOB curve parameters from their mean at otherwise identical 13C-methacetin metabolization rates. In order to correct for this bias we introduced a novel detoxification score which ideally should be assessed from the DOB curve of a 2-step test (“2DOB”) which is initialized with the injection of a standard dose of 13C-labeled bicarbonate (in order to provide information on the actual CO2 status of the individual) followed by injection of the 13C-labeled test drug (the common procedure). Computer simulations suggest that the predictive power of the proposed 2DOB breath test to reliably quantity the CYP-specific hepatic detoxification activity should be significantly higher compared to the conventional breath test. 相似文献
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Patterns of Root Colonization in Epacridaceous Plants Collected from Different Sites 总被引:2,自引:0,他引:2
Root colonization was studied in ten species of the Epacridaceaeat three sites in Victoria by morphological and cross-inoculationexperiments. The sites and genera chosen were Cranbourne [Epacrisimpressa Labill. andLeucopogon ericoides(Smith) R. Br.] andRye [L. parviflorus(Andrews) Lindley] on the Mornington Peninsula,and the Grampians[Astroloma conostephioides(Sond.) Benth.,A.humifusum(Cav.) R. Br.,A pinifolium(R. Br.) Benth,Brachylomadaphnoides(Smith) Benth.,E. impressa, E. impressavar.grandifloraBenth.andStyphelia adscendensR. Br.] in western Victoria. For morphologicalstudies, samples of roots from each species at each site werecleared and stained and examined microscopically. For cross-inoculationstudies, cuttings from each site were struck in potting mediuminoculated with soil from the same and other sites. The ericoidmycorrhizae in the roots of plants found at or grown in Cranbourneand Rye soils were similar. Both were significantly differentfrom the internal hyphae found in the roots of plants foundat or grown in Grampians soils, which were three times largerin diameter and formed dense coils which filled the host celland invaded adjacent epidermal cells. This suggests that morethan one fungus is involved in the relationships, that the MorningtonPeninsula sites had a different fungus from the Grampians siteand that host specificity is low. Vesicular structures werealso found commonly on plants at the Grampians site, in contrastwith other sites. Epacridaceae; root; fungus; mycorrhiza; morphology; inoculation 相似文献
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Gerver WJ De Bruin R Delemarre v d Waal HA Aldewereld B Theunissen P Westerterp KR 《Hormone research》2000,53(5):215-220
This study was directed to the investigation of two different aspects of growth hormone: What are the metabolic consequences following the discontinuation of treatment and are these metabolic effects correlated with the growth-promoting effects seen in the first year of treatment? The study was performed on 12 growth hormone-deficient (GHD) patients who reached their final height. Each patient was matched with a non-GHD person of the same sex and about the same age. Immediately after the discontinuation of treatment, and 6 weeks and 6 months later, the following anthropometric variables were assessed: height, weight, skinfold thicknesses (biceps, triceps, subscapular and suprailiacal), body volume (underwater weighing) and total body water (deuterium dilution). To describe energy metabolism, basal metabolic rate assessed by ventilated hood, and sleep metabolic rate assessed by respiration chamber, were studied. Body composition was calculated from weight, volume and total body water. Clear metabolic effects were found after the discontinuation of treatment in GHD children: there was a decrease in fat free mass and sleep metabolic rate. Also, a strong correlation between the above-mentioned effects and the growth-promoting effects of human growth hormone at the beginning of the treatment was observed. The fact that this correlation exists poses the interesting question of whether the results from a test treatment lasting some weeks could be used to predict the long-term effects of hGH. 相似文献
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Association of the fat mass and obesity‐associated gene risk allele,rs9939609A,and reward‐related brain structures 下载免费PDF全文
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Enrico Moro Rosella Tomanin Adelaide Friso Nicola Modena Natascia Tiso Maurizio Scarpa Francesco Argenton 《Matrix biology》2010,29(1):43-50
Sulfated glycosaminoglycan chains of extracellular matrix and cell membrane-tethered proteoglycans exert specific cellular functions by interacting with a broad spectrum of morphogens and growth factors.In humans, a congenital impaired catabolism of sulfated glycosaminoglycans is associated with severe metabolic disorders. Here, we report on the identification and characterization of a zebrafish iduronate sulfatase orthologue. By knocking down its function with antisense morpholino oligos, we demonstrate that iduronate sulfatase plays a critical role during early vertebrate development and its downregulation may be responsible for severe developmental defects, including a misshapen trunk and abnormal craniofacial cartilages. We show that the altered cartilage patterning is mediated by depauperation of sox10-expressing neural crest cell precursors. Through the application of a transactivation reporter assay, we also provide a molecular proof that increased TGFβ (Transforming Growth Factor β) signalling is tightly associated with downregulation of iduronate sulfatase function. Our results provide an insight into the early biological impairments underlying the Hunter syndrome and suggest the use of zebrafish as a novel tool to better understand lysosomal storage disorder pathogenesis. 相似文献
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Andréia S Lessa Bruno D Paredes Juliana V Dias Adriana B Carvalho Luiz Fernando Quintanilha Christina M Takiya Bernardo R Tura Guilherme FM Rezende Antonio C Campos de Carvalho Célia MC Resende Regina CS Goldenberg 《BMC veterinary research》2010,6(1):1-10