Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate

St. John’s Wort (Hypericum perforatum) is a perennial herb able to produce water-soluble active ingredients (a.i.), mostly in flowers, with a wide range of medicinal and biotechnological uses. However, information about the ability of arbuscular mycorrhizal fungi (AMF) to affect its biomass accumulation, flower production, and concentration of a.i. under contrasting nutrient availability is still scarce. In the present experiment, we evaluated the role of AMF on growth, flower production, and concentration of bioactive secondary metabolites (hypericin, pseudohypericin, and hyperforin) of H. perforatum under contrasting P availability. AMF stimulated the production of aboveground biomass under low P conditions and increased the production of root biomass. AMF almost halved the number of flowers per plant by means of a reduction of the number of flower-bearing stems per plant under high P availability and through a lower number of flowers per stem in the low-P treatment. Flower hyperforin concentration was 17.5% lower in mycorrhizal than in non-mycorrhizal plants. On the contrary, pseudohypericin and hypericin concentrations increased by 166.8 and 279.2%, respectively, with AMF under low P availability, whereas no effect of AMF was found under high P availability. These results have implications for modulating the secondary metabolite production of H. perforatum. However, further studies are needed to evaluate the competition for photosynthates between AMF and flowers at different nutrient availabilities for both plant and AM fungus

Sympathetic activation, ventricular repolarization and Ikrblockade: Implications for the antifibrillatory efficacy of potassium channel blocking agents

AbstractObjectives. The aim of the present study was to test, in vivo and in vitro, the influence of adrenergic activation on action potential prolongation induced by the potassium channel blocking agent d-sotalol.Background. d-Sotalol is not effective against myocardial ischemia-dependent ventricular fibrillation in the presence of elevated sympathetic activity. Most potassium channel blockers, such as d-sotalol, affect only one of the two components of Ik(Ikr) but not the other (Iks). Iksis activated by isoproterenol. An unopposed activation of Iksmight account for the loss of anti-fibrillatory effect by d-sotalol in conditions of high sympathetic activity.Methods. In nine anesthetized dogs we tested at constant heart rate (160 to 220 beats/min) the influences of left stellate ganglion stimulation on the monophasic action potential prolongation induced by d-sotalol. In two groups of isolated guinea pig ventricular myocytes we tested the effect of isoproterenol (10−9mol/liter) on the action potential duration at five pacing rates (from 0.5 to 2., Hz) in the absence (n = 6) and in the presence (n = 8) of d-sotalol.Results. In control conditions, both in vivo and in vitro, adrenergic stimulation did not significantly change action potential duration. d-Sotalol prolonged both monophasic action potential duration in dogs and action potential duration of guinea pig ventricular myocytes by 19% to 24%. Adrenergic activation, either left stellate ganglion stimulation in vivo or isoproterenol in vitro, reduced by 40% to 60% the prolongation of action potential duration produced by d-sotalol.Conclusions. Sympathetic activation counteracts the effects of potassium channel blockers on the duration of repolarization and may impair their primary antifibrillatory mechanism. An intriguing clinical implication is that potassium channel blockers may not offer effective protection from malignant ischemic arrhythmias that occur in a setting of elevated sympathetic activity

In vitro rooting and acclimatization of Sicilian Hypericum perforatum

Hypericum perforatum L. is traditionally used as a medicinal plant because of different bioactive compounds with documented antidepressant and anti-inflammatory activities. Plantlets mass production with high content of these secondary metabolites has been enhanced through in vitro culture but often the process has been stopped at the multiplication phase. A study was conducted in order to set up an efficient in vitro rooting and acclimatization protocol of a H. perforatum Sicilian genotype well-adapted to south Mediterranean conditions. Aseptic nodal segments were cultured on to a Murashige and Skoog (MS) basal medium supplemented with 4.44 μM 6-benzyladenine (BA) for multiplication. Microshoots were then transferred on to specific culture media for in vitro rooting in order to evaluate the nutrients concentration and different auxins effect: full and half-strength hormone-free MS or supplemented with 5.7 μM indole-3-acetic acid (IAA) or 4.9 μM indole-3-butyric acid (IBA). Highest rooting rate was achieved on full-strength MS with IAA 5.7 μM and on all half-strength MS media; higher number of roots was recorded on half-strength MS with IAA and full-strength MS with IBA 4.9 μM; longest roots were measured on full-strength MS with IAA 5.7 μM. Rooted plantlets were ex-vitro acclimatized by transferring them into greenhouse in plastic pots filled with peat:perlite and sand:perlite mixtures (1:1, v/v) under mist: acclimatization rate was higher for rooted plantlets grown in sand/perlite substrate

Occult hepatitis B virus infection predicts non-alcoholic steatohepatitis in severely obese individuals from Italy

Obesity is associated with\ua0non-alcoholic fatty liver (NAFL), which may progress towards non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Occult hepatitis B virus infection (OBI) may contribute to hepatic damage in patients with\ua0chronic liver disease\ua0of different aetiologies (eg\ua0HCV, alcohol). However, information on the prevalence and clinical impact of OBI in obese individuals is lacking. The aims of this study were to investigate NASH prevalence and risk factors in obese people who underwent bariatric surgery

Biogenic Aerosol in the Artic from Eight Years of MSA Data from Ny Ålesund (Svalbard Islands) and Thule (Greenland)

In remote marine areas, biogenic productivity and atmospheric particulate are coupled through dimethylsulfide (DMS) emission by phytoplankton. Once in the atmosphere, the gaseous DMS is oxidized to produce H2SO4 and methanesulfonic acid (MSA); both species can a ect the formation of cloud condensation nuclei. This study analyses eight years of biogenic aerosol evolution and variability at two Arctic sites: Thule (76.5 N, 68.8 W) and Ny Ålesund (78.9 N, 11.9 E). Sea ice plays a key role in determining the MSA concentration in polar regions. At the beginning of the melting season, in April, up to June, the biogenic aerosol concentration appears inversely correlated with sea ice extent and area, and positively correlated with the extent of the ice-free area in the marginal ice zone (IF-MIZ). The upper ocean stratification induced by sea ice melting might have a role in these correlations, since the springtime formation of this surface layer regulates the accumulation of phytoplankton and nutrients, allowing the DMS to escape from the sea to the atmosphere. The multiyear analysis reveals a progressive decrease in MSA concentration in May at Thule and an increase in July August at Ny Ålesund. Therefore, while the MSA seasonal evolution is mainly related with the sea ice retreat in April, May, and June, the IF-MIZ extent appears as the main factor a ecting the longer-term behavior of MSA.MIUR PRIN 2007 and PRIN 2009, PNRA 2010-2012, PNRA 2015-2016, PNRA 2016-2018Publishedid 3495A. Ricerche polari e paleoclimaJCR Journa