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Abstract: Neuronal nitric oxide synthase (NOS1 or nNOS) exerts negative inotropic and positive lusitropic effects through Ca2+ handling processes in cardiac myocytes from healthy hearts. However, underlying mechanisms of NOS1 in diseased hearts remain unclear. The present study aims to investigate this question in angiotensin II (Ang II)-induced hypertensive rat hearts (HP). Our results showed that the systolic function of left ventricle (LV) was reduced and diastolic function was unaltered (echocardiographic assessment) in HP compared to those in shams. In isolated LV myocytes, contraction was unchanged but peak [Ca2+]i transient was increased in HP. Concomitantly, relaxation and time constant of [Ca2+]i decay (tau) were faster and the phosphorylated fraction of phospholamban (PLN-Ser16/PLN) was greater. NOS1 protein expression and activity were increased in LV myocyte homogenates from HP. Surprisingly, inhibition of NOS1 did not affect contraction but reduced peak [Ca2+]i transient; prevented faster relaxation without affecting the tau of [Ca2+]i transient or PLN-Ser16/PLN in HP, suggesting myofilament Ca2+ desensitization by NOS1. Indeed, relaxation phase of the sarcomere length–[Ca2+]i relationship of LV myocytes shifted to the right and increased [Ca2+]i for 50% of sarcomere shortening (EC50) in HP. Phosphorylations of cardiac myosin binding protein-C (cMyBP-C282 and cMyBP-C273) were increased and cardiac troponin I (cTnI23/24) was reduced in HP. Importantly, NOS1 or PKG inhibition reduced cMyBP-C273 and cTnI23/24 and reversed myofilament Ca2+ sensitivity. These results reveal that NOS1 is up-regulated in LV myocytes from HP and exerts positive lusitropic effect by modulating myofilament Ca2+ sensitivity through phosphorylation of key regulators in sarcomere. [Copyright &y& Elsevier]

Pentachlorophenol (PCP), a kind of ionizable hydrophobic organic contaminant, had been extensively used in agricultural, industrial, and domestic applications as an important component of fungicides, bactericides, herbicides, insecticides, biocides, and wood preservatives, To investigate the effects of pentachlorophenol (PCP) on anaerobic digestion system, an experimental study was carried out in which simulated PCP-contaminated sewage water was treated using a batch reactor. The study revealed that the influences of PCP on acidogenic and methanogenic microorganisms. Affected by PCP, the fermentation type of system was transformed from butyric acid type to propionic acid type.Moreover, biogas production rate and methane content were less. PCP inhibited the activity of methane bacteria significantly: during the series of PCP addition (PCP concentration was 0, 14.9, 19.1, and 29.5mg/ L, respectively), the higher the PCP concentration was, the more serious the inhibition effect was. The removal rate of PCP was 94.6% when the PCP concentration was 14.9 mg/L, while it was only 54.8% when PCP concentration was raised to 29.5 mg/L. Acidogenic microorganism was more quickly adaptable for PCP than methanogenic microorganism [ABSTRACT FROM AUTHOR]