SYNOPSIS. The presence of nitric oxide synthase (NOS) activity is demonstrated in the tropical marine cnidarian Aiptasia pallida and in its symbiotic dinoflagellate algae, Symbiodinium bermudense. Enzyme activity was assayed by measuring the conversion of arginine to citrulline. Biochemical characterization of NOS from Aiptasia was characterized with respect to cellular localization, substrate ...

Nitric oxide is a chemical messenger which functions as a neurotransmitter or as a cytotoxic agent. Nitric oxide synthase (NOS) has been isolated from various mammalian reproductive tissues. The presence or absence of NOS in spermatozoa has not yet been reported. We therefore tested human and murine spermatozoa for NOS activity by measuring the conversion of arginine to citrulline. No activity ...

Nitric oxide (NO) is a free radical which is produced from a wide variety of cells and tissues in the human body. NO is involved in the regulation of many physiological processes, such as vascular relaxation, neurotransmission, immune regulation, and cell death. NO is generated by nitric oxide synthase (NOS), which has three identified isoforms: neuronal type NOS (nNOS), endothelial type NOS (e...

Muscle satellite cells are quiescent precursors interposed between myofibers and a sheath of external lamina. Although their activation and recruitment to cycle enable muscle repair and adaptation, the activation signal is not known. Evidence is presented that nitric oxide (NO) mediates satellite cell activation, including morphological hypertrophy and decreased adhesion in the fiber-lamina com...

Nitric oxide contributes to estrogen-mediated uterine vasodilation; however, the nitric oxide synthases (NOS) involved and their location within uterine arteries are incompletely documented. We investigated the effects of repetitive daily and acute estradiol-17beta (E(2)beta) exposure on uterine hemodynamics and NOS abundance and localization in uterine arteries from nonpregnant ovariectomized ...

To investigate the possible role of nitric oxide (NO) produced locally or intramurally in the quiescence of the pregnant myometrium, nitric oxide synthase (NOS) activity was measured in samples from first trimester (villous, and non villous-trophoblast), term placenta and pregnant myometrium. Trophoblast tissue was obtained from psychosocial termination of pregnancy (9-12 weeks' gestation) wher...

Members of the nanos gene family are evolutionarily conserved regulators of germ cell development. In several organisms, Nanos protein expression is restricted to the primordial germ cells (PGCs) during early embryogenesis. Here, we investigate the regulation of the Caenorhabditis elegans nanos homolog nos-2. We find that the nos-2 RNA is translationally repressed. In the adult germline, transl...

The activity of nitric oxide synthase (NOS) has recently been shown to increase transiently but dramatically in chick embryonic myoblasts that are competent for fusion and that NO acts as a messenger for the cell fusion. Here we show that the rise in NOS activity is tightly correlated with an increase in NOS protein level, and its synthesis is under transcriptional control. In addition, a parti...

Earlier studies have demonstrated evidence for increased reactive oxygen species, enhanced NO synthase (NOS) expression, and elevated NO production in spontaneously hypertensive rats (SHR). Given the negative-feedback regulation of NOS by NO, we hypothesized that enhanced NO inactivation by ROS may contribute to compensatory upregulation of NOS in SHR. The present study was designed to test thi...

Background: NO is an important cellular signaling molecule which is derived from L-arginine by nitric oxide synthase (NOS) and the effects of NOS signaling in lung injury is conflicting. The present study was designed to observe the effect of NOS and Arginase signaling in the occurrence and development of lung injury and its mechanism. Methods: An ozone-stressed lung injury animal model was est...