Acido solfidrico nella letteratura internazionale

Discoveries on the toxic effects of cysteine accumulation and, particularly, recent findings on the many physiological roles of one of the products of cysteine catabolism, hydrogen sulfide (H2S), are highlighting the importance of this amino acid and sulfur metabolism in a range of cellular activities. It is also highlighting how little we know about this critical part of cellular metabolism. In the work described here, a genome-wide screen using a deletion collection of Saccharomyces cerevisiae revealed a surprising set of genes associated with this process. In addition, the yeast vacuole, not previously associated with cysteine catabolism, emerged as an important compartment for cysteine degradation. Most prominent among the vacuole-related mutants were those involved in vacuole acidification; we identified each of the eight subunits of a vacuole acidification sub-complex (V1 of the yeast V-ATPase) as essential for cysteine degradation. Other functions identified included translation, RNA processing, folate-derived one-carbon metabolism, and mitochondrial iron-sulfur homeostasis. This work identified for the first time cellular factors affecting the fundamental process of cysteine catabolism. Results obtained significantly contribute to the understanding of this process and may provide insight into the underlying cause of cysteine accumulation and H2S generation in eukaryotes (27) Desloover J, De VJ, Van d, V, Mortelmans J, Rozendal R, Rabaey K. Electrochemical Nutrient Recovery Enables Ammonia Toxicity Control and Biogas Desulfurization in Anaerobic Digestion. Environ Sci Technol 2015 Jan 6. Abstract: Organic waste streams can be valorized and reduced in volume with anaerobic digestion (AD). An often-encountered key issue however is the high ammonium (NH4+) content of certain waste streams. Ammonia (NH3), in equilibrium with NH4+, is a toxic compound to the methanogenic community, which limits the organic loading rate and endangers process stability. An electrochemical system (ES) linked to a digester could, besides recovering this nutrient, decrease NH3 toxicity through electrochemical extraction. Therefore, two digesters with and without ES attached in the recirculation loop were operated to test whether the ES could control NH3 toxicity. During periods of high ammonium loading rates, the methane (CH4) production of the ES-coupled reactor was up to 4.5 times higher compared to the control, which could be explained through simultaneous NH4+ extraction and electrochemical pH control. A nitrogen flux of 47 g N m-2 membrane d-1 could be obtained in the ES-coupled reactor, resulting in a current and removal efficiency of 38 +/5% and 28 +/2%, respectively, at an electrochemical power input of 17 +/2 kWh kg-1 N. The anode also oxidized sulfide, resulting in a significantly lower H2S emission via the biogas. Lastly, limited methanogenic community dynamics pointed to a nonselective influence of the different operational conditions (28) Zhou X, Zhao L, Mao J, Huang J, Chen J. Antioxidant effects of hydrogen sulfide on left ventricular remodeling in smoking rats are mediated via PI3K/Akt-dependent activation of Nrf2. Toxicol Sci 2014 Dec 16. Abstract: There is growing evidence that oxidative stress plays critical roles in the pathogenesis of cardiac remodeling. In the present study, we established a rat model of passive smoking and investigated the antioxidant effects of hydrogen sulfide (H2S) on smoking-induced left ventricular remodeling. Cardiac structure and function were evaluated using two-dimensional echocardiography. Myocardial fibrosis was detected by Masson's trichrome staining and immunohistochemistry. Oxidative stress was assessed by measuring malondialdehyde levels, superoxide dismutase and glutathione peroxidase activities, and reactive oxygen species generation in the myocardium. Neonatal rat cardiomyocytes transfected with specific siRNA and exposed to cigarette smoke condensate and H2S donor sodium hydrosulfide were used to confirm the involvement of Nrf2 and PI3K/Akt signaling in the antioxidant effects of H2S. Our results indicated that H2S could protect against left ventricular remodeling in smoking rats via attenuation of oxidative stress. Moreover, H2S was also found to increase the phosphorylation of Akt and GSK3beta and decrease the nuclear expression of Fyn, which consequently leads to nuclear translocation of Nrf2 and elevated expression of HO-1 and NQO1. In conclusion,