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991.
992.
993.
Jo?o B. Vicente Henrique G. Cola?o Paolo Sarti Paula Leandro Alessandro Giuffrè 《The Journal of biological chemistry》2016,291(2):572-581
Cystathionine β-synthase (CBS) is a key enzyme in human (patho)physiology with a central role in hydrogen sulfide metabolism. The enzyme is composed of a pyridoxal 5′-phosphate-binding catalytic domain, flanked by the following two domains: a heme-binding N-terminal domain and a regulatory C-terminal domain binding S-adenosyl-l-methionine (AdoMet). CO or NO• binding at the ferrous heme negatively modulates the enzyme activity. Conversely, AdoMet binding stimulates CBS activity. Here, we provide experimental evidence for a functional communication between the two domains. We report that AdoMet binding significantly enhances CBS inhibition by CO. Consistently, we observed increased affinity (∼5-fold) and faster association (∼10-fold) of CO to the ferrous heme at physiological AdoMet concentrations. NO• binding to reduced CBS was also enhanced by AdoMet, although to a lesser extent (∼2-fold higher affinity) as compared with CO. Importantly, CO and NO• binding was unchanged by AdoMet in a truncated form of CBS lacking the C-terminal regulatory domain. These unprecedented observations demonstrate that CBS activation by AdoMet puzzlingly sensitizes the enzyme toward inhibition by exogenous ligands, like CO and NO•. This further supports the notion that CBS regulation is a complex process, involving the concerted action of multiple physiologically relevant effectors. 相似文献
994.
995.
Effect of grazing on the population of Matteuccia struthiopteris at the southern limit of its distribution in Europe 下载免费PDF全文
Marco Landi Antonio Zoccola Vincenzo Gonnelli Lorenzo Lastrucci Carlo Saveri Giovanni Quilghini Alessandro Bottacci Claudia Angiolini 《Plant Species Biology》2016,31(1):3-10
We investigated the impact of deer on an isolated marginal population of Matteuccia struthiopteris and on its plant community in the northern Apennines, where in recent decades the species has decreased dramatically. Our experiment was based on a 6‐year before and after control impact (BACI) design, comparing plots with deer grazing and plots where deer were excluded. Exclusion of grazing interacted with years, increasing the size of existing plants and favoring production of sporophylls. The yearly sequence of increase and decline of ramets and sterile leaves followed the same pattern in the two treatments. This indicated that their annual variation in growth depended on the sequence of more and less favorable years. Few and short plants were associated with grazing, whereas tall plants, shrubs, and tree regeneration were associated with fenced plots. The few plants to persist and dominate on heavily grazed areas were Oxalis acetosella and Cardamine species, while the genus Rubus and tree saplings were grazing‐sensitive species in this forest. Tall herbaceous species increased in size in the fenced areas, however, M. struthiopteris drew more advantage in terms of growth of leaves, showing greater cover than other species. Thus, deer grazing is becoming a threat for the survival of M. struthiopteris in southern Europe where it is already threatened in the long term by climate change. 相似文献
996.
Gabriela C. Canton Amanda A. Bertolazi Antônio J. D. Cogo Frederico Jacob Eutrópio Juliana Melo Sávio Bastos de Souza Cesar A. Krohling Eliemar Campostrini Ary Gomes da Silva Arnoldo R. Façanha Nuno Sepúlveda Cristina Cruz Alessandro C. Ramos 《Mycorrhiza》2016,26(5):475-487
At relatively low concentrations, the element manganese (Mn) is essential for plant metabolism, especially for photosynthesis and as an enzyme antioxidant cofactor. However, industrial and agricultural activities have greatly increased Mn concentrations, and thereby contamination, in soils. We tested whether and how growth of Pisolithus tinctorius is influenced by Mn and glucose and compare the activities of oxidative stress enzymes as biochemical markers of Mn stress. We also compared nutrient accumulation, ecophysiology, and biochemical responses in Eucalyptus grandis which had been colonized by the ectomycorrhizal Pisolithus tinctorius with those which had not, when both were exposed to increasing Mn concentrations. In vitro experiments comprised six concentrations of Mn in three concentrations of glucose. In vivo experiments used plants colonized by Pisolithus tinctorius, or not colonized, grown with three concentrations of Mn (0, 200, and 1000 μM). We found that fungal growth and glucose concentration were correlated, but these were not influenced by Mn levels in the medium. The anti-oxidative enzymes catalase and glutathione S-transferase were both activated when the fungus was exposed to Mn. Also, mycorrhizal plants grew more and faster than non-mycorrhizal plants, whatever Mn exposure. Photosynthesis rate, intrinsic water use efficiency, and carboxylation efficiency were all inversely correlated with Mn concentration. Thus, we originally show that the ectomycorrhizal fungus provides protection for its host plants against varying and potentially toxic concentrations of Mn. 相似文献
997.
J.A. Aguilera Sammaritano C.C. López Lastra A. Leclerque F. Vazquez M.E. Toro C.P. D’Alessandro 《Biocontrol Science and Technology》2016,26(12):1668-1682
Entomopathogenic Hypocreales were isolated from arid soils in Argentina using Tenebrio molitor as bait and tested for their biological performance at 30°C and 45–65% RH. Conidial germination was tested in three vegetable oils (sunflower, olive and maize) at two concentrations (1% and 10%) to evaluate their compatibility for further liquid formulations. According to radial growth and germination results, we selected four isolates to test their pathogenicity against second instar B. tabaci nymphs with the selected oil formulations at 30°C. CEP381 and CEP401 showed the highest radial growth. Isolates CEP381, CEP401, CEP413 and CEP409 (Metarhizium spp.) had similar germination percentages as compared with water control when germinated on either sunflower, olive or maize oils at 10% v/v. The highest mortality of B. tabaci was observed for the isolates CEP381 in sunflower oil and CEP401 in olive oil. Molecular identification of isolates was performed using ITS4–5 primers. All isolates belong to the Metarhizium core group. Tested isolates could grow and infect B. tabaci nymphs at 30°C in some of the vegetable oils as carriers, providing new possibilities for integrated pest management of Bemisia tabaci. 相似文献
998.
Alessandro Pratesi Damiano Cirri Mirjana D. Đurović Serena Pillozzi Giulia Petroni Živadin D. Bugarčić Luigi Messori 《Biometals》2016,29(5):905-911
Three structurally related gold(I) carbene complexes with bulky hydrophobic ligands i.e. 1–3 were investigated in solution for further consideration as candidate anticancer agents. Cytotoxic assays were subsequently conducted on bone marrow-derived preosteoclast cell line of human origin (FLG 29.1) and human colon cancer cells (HCT-116). A far greater cytotoxic activity was measured for compound 1 against HCT-116 cells compared to 2 and 3; conversely, all compounds were highly and similarly active against FLG 29.1 cells. Results obtained for the reaction of complexes 1 and 2 with RNase A documented the occurrence of a weak interaction with this model protein and the formation of a tiny amount of the corresponding adduct. Moreover, a certain reactivity of the complex 2 was also detected toward GSH. The general implications of the obtained results are discussed. 相似文献
999.
1000.
Alessandro Scopelliti Christin Bauer Marcos Vidal 《Cell cycle (Georgetown, Tex.)》2016,15(12):1538-1544
Bursicon is the main regulator of post molting and post eclosion processes during arthropod development. The active Bursicon hormone is a heterodimer of Burs-α and Burs-β. However, adult midguts express Burs-α to regulate the intestinal stem cell niche. Here, we examined the potential expression and function of its heterodimeric partner, Burs-β in the adult midgut. Unexpectedly, our evidence suggests that Burs-β is not significantly expressed in the adult midgut. burs-β mutants displayed the characteristic developmental defects but showed wild type-like adult midguts, thus uncoupling the developmental and adult phenotypes seen in burs-α mutants. Gain of function data and ex vivo experiments using a cAMP biosensor, demonstrated that Burs-α is sufficient to drive stem cell quiescence and to activate dLGR2 in the adult midgut.
Our evidence suggests that the post developmental transactivation of dLGR2 in the adult midgut is mediated by Burs-α and that the β subunit of Bursicon is dispensable for these activities. 相似文献