The pore of the catfish olfactory cyclic nucleotide-gated (CNG) channel contains four conserved glutamate residues, one from each subunit, that form a high-affinity binding site for extracellular divalent cations. Previous work showed that these residues form two independent and equivalent high-pKa (approximately 7.6) proton binding sites, giving rise to three pH-dependent conductance states, a...

Cyclic nucleotide-gated (CNG) channels are crucial for phototransduction in vertebrate rod photoreceptors. The cGMP sensitivity of these channels is modulated by diffusible intracellular messengers, including Ca2+/calmodulin, contributing to negative feedback during sensory adaptation. Membrane-associated protein tyrosine kinases and phosphatases also modulate rod CNG channels, but whether this...

Odor stimulation of olfactory sensory neurons (OSNs) leads to both the activation and subsequent desensitization of a heteromultimeric cyclic-nucleotide-gated (CNG) channel present in these cells. The native olfactory CNG channel consists of three distinct subunits: CNGA2, CNGA4, and CNGB1b. Mice in which the CNGA4 gene has been deleted display defective Ca(2+)calmodulin-dependent inhibition of...

In the mammalian retina, cone photoreceptors efficiently adapt to changing background light intensity and, therefore, are able to signal small differences in luminance between objects and backgrounds, even when the absolute intensity of the background changes over five to six orders of magnitude. Mammalian rod photoreceptors, in contrast, adapt very little and only at intensities that nearly sa...

Human olfaction comprises the opposing actions of excitation and inhibition triggered by odorant molecules. In olfactory receptor neurons, odorant molecules not only trigger a G-protein-coupled signaling cascade but also generate various mechanisms to fine tune the odorant-induced current, including a low-selective odorant inhibition of the olfactory signal. This wide-range olfactory inhibition...

Cyclic nucleotide-gated (CNG) channels are key elements of cGMP- and cAMP-signaling pathways in vertebrate photoreceptor cells and in olfactory sensory neurons, respectively. These channels form heterooligomeric complexes composed of at least two distinct subunits (alpha and beta). The alpha subunit of cone photoreceptors is also present in mammalian sperm. Here we identify one short and severa...

Cyclic nucleotide-gated (CNG) channels are key elements of cGMPand cAMP-signaling pathways in vertebrate photoreceptor cells and in olfactory sensory neurons, respectively. These channels form heterooligomeric complexes composed of at least two distinct subunits ( a and b ). The a subunit of cone photoreceptors is also present in mammalian sperm. Here we identify one short and several long less...

The preparation of air–fuel mixture is considerably dependent on fluid flow dynamics to achieve improved performance, efficiency, and engine combustion in the appearance of flow. In this study, the effects of mixtures of hydrogen and compressed natural gas (CNG) on a spark ignition engine are numerically considered. This article presents the results of a direct-injection engine using methane–hy...

the present study was conducted to investigate the impacts of retrofitted cng vehicles on airpollutant emissions in tehran over a 20 years period using available statistical data, precise automobile tests, data analysis, and leap software. the obtained results revealed an increase in air pollutant emissionsincluding co (equal to 1030.77 thousand tons), nox (equal to 1030.77 thousand tons), thc ...

the present study was conducted to investigate the impacts of retrofitted cng vehicles on airpollutant emissions in tehran over a 20 years period using available statistical data, precise automobile tests, data analysis, and leap software. the obtained results revealed an increase in air pollutant emissionsincluding co (equal to 1030.77 thousand tons), nox (equal to 1030.77 thousand tons), thc ...