Daily NO rhythms in peripheral clocks in aging male Wistar rats: protective effects of exogenous melatonin.

Daily NO rhythms in peripheral clocks in aging male Wistar rats: protective effects of exogenous melatonin.

In mammals suprachiasmatic nucleus (SCN), acts as a light entrainable master clock and by generation of temporal oscillations regulates the peripheral organs acting as autonomous clocks resulting in overt behavioral and physiological rhythms. SCN also controls synthesis and release of melatonin (hormonal message for darkness) from pineal. Nitric Oxide (NO) acts as an important neurotransmitter in generating the phase shifts of circadian rhythms and participates in sleep-wake processes, maintenance of vascular tone as well as signalling and regulating inflammatory processes. Aging is associated with disruption of circadian timing system and decline in endogenous melatonin leading to several physiological disorders. Here we report the effect of aging on NO daily rhythms in various peripheral clocks such as kidney, intestine, liver, heart, lungs and testis. NO levels were measured at zeitgeber time (ZT) 0, 6, 12 and 18 in these tissues using Griess assay in male Wistar rats. Aging resulted in alteration of NO levels as well as phase of NO in both 12 and 24 months groups. Correlation analysis demonstrated loss of stoichiometric interaction between the various peripheral clocks with aging. Age induced alterations in NO daily rhythms were found to be most significant in liver and, interestingly least in lungs. Neurohormone melatonin, an endogenous synchroniser and an antiaging agent decreases with aging. We report further differential restoration with exogenous melatonin administration of age induced alterations in NO daily rhythms and mean levels in kidney, intestine and liver and the stoichiometric interactions between the various peripheral clocks.

KEYWORDS: Aging; Daily rhythms; Melatonin; NO; Peripheral clocks

 

 

http://www.ncbi.nlm.nih.gov/pubmed/27614960

 

2. Direct observation of rotation and steps of the archaellum in the swimming halophilic archaeon Halobacterium salinarum

Motile archaea swim using a rotary filament, the archaellum, a surface appendage that resembles bacterial flagella structurally, but is homologous to bacterial type IV pili. Little is known about the mechanism by which archaella produce motility. To gain insights into this mechanism, we characterized archaellar function in the model organism Halobacterium salinarum. Three-dimensional tracking of quantum dots enabled visualization of the left-handed corkscrewing of archaea in detail. An advanced analysis method combined with total internal reflection fluorescence microscopy, termed cross-kymography, was developed and revealed a right-handed helical structure of archaella with a rotation speed of 23 ± 5 Hz. Using these structural and kinetic parameters, we computationally reproduced the swimming and precession motion with a hydrodynamic model and estimated the archaellar motor torque to be 50 pN nm. Finally, in a tethered-cell assay, we observed intermittent pauses during rotation with ∼36° or 60° intervals, which we speculate may be a unitary step consuming a single adenosine triphosphate molecule, which supplies chemical energy of 80 pN nm when hydrolysed. From an estimate of the energy input as ten or six adenosine triphosphates per revolution, the efficiency of the motor is calculated to be ∼6–10%.

http://www.nature.com/articles/nmicrobiol2016148

 

KEYWORDS: Chromosomal damage; Ionizing radiation; Plants

 

http://www.ncbi.nlm.nih.gov/pubmed/27614909

KEYWORDS: Ethnobotany; Indigenous knowledge; Karakorum; Medicinal plants; Pakistan

http://www.ncbi.nlm.nih.gov/pubmed/27612599

KEYWORDS: aquatic environment, microplastic, polymers, spectroscopic methods, waterborne pollutants

http://www.ncbi.nlm.nih.gov/pubmed/27618688

 

Daily NO rhythms in peripheral clocks in aging male Wistar rats: protective effects of exogenous melatonin.

In mammals suprachiasmatic nucleus (SCN), acts as a light entrainable master clock and by generation of temporal oscillations regulates the peripheral organs acting as autonomous clocks resulting in overt behavioral and physiological rhythms. SCN also controls synthesis and release of melatonin (hormonal message for darkness) from pineal. Nitric Oxide (NO) acts as an important neurotransmitter in generating the phase shifts of circadian rhythms and participates in sleep-wake processes, maintenance of vascular tone as well as signalling and regulating inflammatory processes. Aging is associated with disruption of circadian timing system and decline in endogenous melatonin leading to several physiological disorders. Here we report the effect of aging on NO daily rhythms in various peripheral clocks such as kidney, intestine, liver, heart, lungs and testis. NO levels were measured at zeitgeber time (ZT) 0, 6, 12 and 18 in these tissues using Griess assay in male Wistar rats. Aging resulted in alteration of NO levels as well as phase of NO in both 12 and 24 months groups. Correlation analysis demonstrated loss of stoichiometric interaction between the various peripheral clocks with aging. Age induced alterations in NO daily rhythms were found to be most significant in liver and, interestingly least in lungs. Neurohormone melatonin, an endogenous synchroniser and an antiaging agent decreases with aging. We report further differential restoration with exogenous melatonin administration of age induced alterations in NO daily rhythms and mean levels in kidney, intestine and liver and the stoichiometric interactions between the various peripheral clocks.