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The genus Hypericum has received considerable interest from scientists, as it contains the variety of structurally diverse natural products which possess a wide array of biological properties, mainly hypericins and hyperforin. In the present study, variations of pseudohypericin and hyperforin were investigated in two Turkish species of Hypericum, namely Hypericum perfoliatum and Hypericum origanifolium. Wild growing plants were harvested at vegetative, floral budding, flowering, fresh fruiting and mature fruiting stages, and dissected into stem, leaf and reproductive tissues and assayed for chemical contents by high performance liquid chromatography method. Content of pseudohypericin and hyperforin in samples of the whole plant increased during the course of ontogenesis in both species. The highest levels of the chemicals were reached at full flowering (2.62 mg/g dry weight (DW) pseudohypericin and 1.84 mg/g DW hyperforin for H. perfoliatum; 0.93 mg/g DW pseudohypericin and 1.63 mg/g DW hyperforin for H. origanifolium). Among different reproductive parts, full opened flowers produced the highest amount of pseudohypericin (1.18 mg/g DW) and hyperforin (4.36 mg/g DW) in H. origanifolium. Similarly, the highest pseudohypericin accumulation was observed in full opened flowers in H. perfoliatum (7.41 mg/g DW) while floral buds of this species produced the highest amount of hyperforin (7.80 mg/g DW). These data can be useful when elucidating the medicinal properties of the species and the chemosystematic significance of hyperforin and pseudohypericin in the relationships among species of Hypericum.  相似文献   
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Obesity is often associated with abnormalities in cardiac morphology and function. This study tested the hypothesis that obesity-related cardiomyopathy is caused by impaired cardiac energetics. In a mouse model of high-fat diet (HFD)-induced obesity, we applied in vivo cardiac 31P magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) to investigate cardiac energy status and function, respectively. The measurements were complemented by ex vivo determination of oxygen consumption in isolated cardiac mitochondria, the expression of proteins involved in energy metabolism, and markers of oxidative stress and calcium homeostasis. We also assessed whether HFD induced myocardial lipid accumulation using in vivo 1H MRS, and if this was associated with apoptosis and fibrosis. Twenty weeks of HFD feeding resulted in early stage cardiomyopathy, as indicated by diastolic dysfunction and increased left ventricular mass, without any effects on systolic function. In vivo cardiac phosphocreatine-to-ATP ratio and ex vivo oxygen consumption in isolated cardiac mitochondria were not reduced after HFD feeding, suggesting that the diastolic dysfunction was not caused by impaired cardiac energetics. HFD feeding promoted mitochondrial adaptations for increased utilization of fatty acids, which was however not sufficient to prevent the accumulation of myocardial lipids and lipid intermediates. Myocardial lipid accumulation was associated with oxidative stress and fibrosis, but not apoptosis. Furthermore, HFD feeding strongly reduced the phosphorylation of phospholamban, a prominent regulator of cardiac calcium homeostasis and contractility. In conclusion, HFD-induced early stage cardiomyopathy in mice is associated with lipotoxicity-associated oxidative stress, fibrosis, and disturbed calcium homeostasis, rather than impaired cardiac energetics.  相似文献   
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  1. In shallow‐water sediments, the combined action of microphytobenthos and bioturbating fauna may differentially affect benthic nutrient fluxes and exert a bottom‐up control of pelagic primary production. In many cases, the effects of microphytobenthos and macrofauna on nutrient cycling were studied separately, ignoring potential synergistic effects.
  2. We measured the combined effects of microphytobenthos and chironomid larvae on sediment–water fluxes of gas (O2, TCO2 and N2) and nutrients (NH4+, NO3?, NO2?, and SiO2) in shallow‐water sediments of a hypertrophic freshwater lagoon. Fluxes were measured in the light and in the dark in reconstructed sediments with low (L = 600 ind/m2), high (H = 1,800 ind/m2) and no (C) addition of chironomid larvae, after 3 weeks of pre‐incubation under light/dark regime to allow for microalgal growth. Besides flux measurements, pore water nutrient (NH4+, and SiO2) and dissolved metal concentrations (Fe2+ and Mn2+) were analysed and diffusive fluxes were calculated.
  3. Chironomid larvae increased sediment heterotrophy, by augmenting benthic O2 demand and TCO2 and N2 dark production. However, on a daily basis, treatments C and L were net O2 producing and N2 sinks while treatment H was net O2 consuming and N2 producing. All treatments were net C sink regardless of chironomid density.
  4. Microphytobenthos always affected benthic nutrient exchange, as significantly higher uptake or lower efflux was measured in the light compared with dark incubations. Theoretical inorganic N, P and Si demand by benthic microalgae largely exceeded both dark effluxes of NH4+, and SiO2 and their net uptake in the light, suggesting the relevance of N‐fixation, water column NO3? and solid‐phase associated P and Si as nutrient sources to benthic algae.
  5. Chironomid larvae had a minor effect on inorganic N and P fluxes while they significantly stimulated inorganic Si regeneration. Their bioturbation activity significantly altered pore water chemistry, with a major reduction in nutrient (highest for NH4+ and lowest for SiO2) and metal concentration. Underlying mechanisms are combinations of burrow ventilation and bioirrigation with stimulation of element‐specific processes as coupled nitrification–denitrification, co‐precipitation and inhibition of anaerobic paths such as Fe3+ or Mn4+ reduction or re‐oxidation of their end products.
  6. The combined activity of benthic algae and chironomid larvae may significantly attenuate internal nutrient recycling in shallow eutrophic ecosystems, and contribute to the control of pelagic primary production.
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The genus Hypericum has received considerable interest from scientists, as it contains the variety of structurally diverse natural products which possess a wide array of biological properties. The present study was conducted to determine ontogenetic and morphogenetic variation of hypericin, chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin and quercetin content in Hypericum origanifolium growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Hypericin, quercetin and quercitrin content in whole plant increased during course of ontogenesis and the highest level was reached in blooming stage. On the contrary, hyperoside content of whole plant decreased linearly with advancing of development stages and the highest level was observed at vegetative stage. Plants produced similar amount of chlorogenic acid at all stages of plant phenology except for mature fruiting at which the amount of this compound was decreased sharply. Among different tissues, reproductive parts accumulated the highest level of hypericin, quercetin and quercitrin, however, leaves produced substantially higher amount of chlorogenic acid and hyperoside. Rutin and apigenin-7-O-glucoside were detectable in all tissues only during fruit maturation. The presence and variation of these bioactive substances in H. origanifolium were reported for the first time.  相似文献   
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Catecholamines may stimulate enteric bacteria including the foodborne pathogen Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) by two mechanisms in vivo: as a quorum sensing signal and a supplier of iron. To identify genes of Salmonella Typhimurium that respond to norepinephrine, transposon mutagenesis and DNA microarray analysis were performed. Insertional mutations in the following genes decreased norepinephrine-enhanced growth: degS, entE, entF, fes, gpmA, hfq, STM3846. DNA microarray and real-time RT-PCR analyses revealed a decrease in the expression of several genes involved in iron acquisition and utilization during norepinephrine exposure, signifying the iron-limiting conditions of serum-SAPI minimal medium and the siderophore-like activity of norepinephrine. Unlike the wild-type parent strain, growth of neither a fepA iroN cirA mutant nor a fepC mutant, harboring deletional mutations in the outer and inner membrane transporters of enterochelin, respectively, was enhanced by norepinephrine. However, growth of the fepC and the fepA iroN cirA mutants could be rescued by an alternative siderophore, ferrioxamine E, further validating the role of norepinephrine in supplying the organism with iron via the catecholate-specific iron transport system. Contrary to previous reports using small animal models, the fepA iroN cirA mutant of Salmonella Typhimurium colonized the swine gastrointestinal tract, as did the fepC mutant.  相似文献   
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Hypericum perforatum is a perennial medicinal plant known as "St. John's wort" in Western Europe and has been used in the treatment of several diseases for centuries. In the present study, morphologic, phenologic and population variability in pseudohypericin and hyperforin concentrations among H. perforatum populations from Northern Turkey was investigated for the first time. The aerial parts of H. perforatum plants representing a total of 30 individuals were collected at full flowering from 10 sites of Northern Turkey to search the regional variation in the secondary metabolits concentrations. For morphologic and phenologic sampling, plants from one site were gathered in five phenological stages vegetative,floral budding, full flowering, fresh fruiting and mature fruiting. The plant materials were air-dried at room temperature and subsequently assayed for chemical concentrations by high performance liquid chromatography. Secondary metabolite concentrations ranged from traces to 2.94mg/g dry weight (DW) for pseudohypedcin and traces -6.29mg/g DW for hyperforin. The differences in the secondary metabolite concentrations among populations of H. perforatum were found to be significant. The populations varied greatly in hyperforin concentrations, whereas they produced a similar amount of pseudohypericin. Concentrations of both secondary metabolites in all tissues increased with advancing of plant development and higher accumulation levels were reached at flowering. Among different tissues, full opened flowers were found to be superior to stems, leaves and the other reproductive parts with regard to pseudohypericin and hyperforin accumulations. The present findings might be useful to optimize the processing methodology of wild-harvested plant material and obtain Increased concentrations of these secondary metabolites.  相似文献   
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