Scientific studies show that white light of LEDs is that most affects the melatonin . This hormone controls the body's circadian rhythm and protects against various diseases, including degenerative disorders, or certain types of cancer.
A study by the American Geophysical Union indicates that the brightness of this light increases air pollution, by interfering with certain chemical reactions . Could generate more nitrogen oxides, one of the gases involved in urban pollution.
Some species may be harmed by
white light LEDs emit a large amount of radiation in shorter wavelengths. It is therefore the best possible light alters the behavior of the species of nightlife. The regulations require more advanced lighting fixtures below the 440 nm emission of luminous flux, a value that exceeds the current white LEDs.
How the body maintains the pace
The biological clock has to do not only with sleep-wake cycles but with pressure blood, body temperature or the effect of drugs
An organism is the result of many subsystems that work in coordination with an internal clock that sets the pace. A clock which also marches to the beat of what happens in the environment: day-night, spring-summer ... In recent decades the study of how the clock has become a booming area. But much to know. How do I adjust the internal and external clocks in the body? or what changes in each cell means the ticking clock? Two research groups pioneered the study of circadian rhythms have just launched two major advances and one may provide clues on why seasonal depression.
* Author: By MONICA G. SALOMON
* Publication Date: May 17, 2007
Fbxl3 Gene
The rate of organisms is inscribed in the genes, and in recent years researchers have been spent searching in model organisms such as Drosophila or mouse, the major genetic pathways involved in timekeeping. As with the systems that play an important role in the body, these networks of genes appear to have been conserved throughout evolution, are similar, for example, insects and mammals. They are not simple networks. In mice, since the discovery of the first gene associated with circadian rhythms in 1997-a gene called Clock-have found five more that are critical. And those genes, in turn, control other large gene families with patterns of recurrent activity.
Joseph Takahashi of Northwestern University and the Howard Hughes Medical Institute (USA) and one of the pioneers in research on biological clocks -author of the Clock-finding, recently published in the journal Cell the discovery of another gene more, also key in mice. "He had already been identified group of genes that form the circadian feedback loop, we had reason to suspect that there are more genes involved in the machinery, "explained Takahashi. The new gene is found special.
In recent years researchers have been dedicated to finding the major genetic pathways involved in timekeeping
is the first related to the circadian oscillations-day-in the quantities and types of proteins within the cell: "We assume that the circadian clock function are proteins that have to come and go [in the cell] in relatively short time scales, "says Takahashi," but we were concerned about how this happens. " Now you have a clue. The new gene related to control biological clock called Fbxl3, and belongs to a family of genes that help destroy certain proteins when they are no longer needed within the cell. In particular, dealing with "signal" to two proteins with circadian oscillation, Cryptochrome 1 and Cryptochrome 2, for destruction.
And these two proteins - specifically, their degradation, are themselves essential to activate the genes Period, marking the beginning of a new circadian cycle. Recap: Fbxl3 help out of the way to protein Cryptochrome when not needed, the degradation of active Cryptochrome Period, and so begins a new cycle, so that other genes are turned on ordering the synthesis of other proteins with circadian oscillation.
Takahashi's group have discovered thanks to a mutant mouse, Overtime, they found after analyzing some 3,000 mice, and whose ability is to follow a circadian rhythm of 26 hours instead of 24. Now we know that the clock moves slowly overtime because it has a mutation that prevents Fbxl3 remove excess Cryptochrome proteins, and therefore does not allow journalists to be activated properly. Takahashi and his colleagues continue to investigate the role of protein degradation in regulating the biological clock.
light therapies
The group's work by Michael Rosbash, Brandeis University and the Howard Hughes Medical Institute (USA) and also published in Cell, has to do with the time setting of internal clock with the environment: how the body feels the changes more subtle than the day and night, and acts accordingly. This time the researchers worked with Drosophila, but Rosbash says the results help us understand animal behaviors such as migration, hibernation or rut. To Dan Stoleru, Rosbash lab and one of the authors of the study, this study provides further information on possible causes of seasonal depression and other psychological disorders that respond to light treatments. How
investigating the sleep-wake cycle in flies? How flies sleep? Call it sleep or not, the truth is that flies alternating periods of activity and inactivity. Presented, in particular, two characteristic peaks of activity in the morning and evening. Each, as he had already determined the group Rosbash, is genetically controlled by a specific group of brain cells to circadian oscillations: cells in the morning and afternoon.
Researchers believe that there is probably a link between depression and circadian rhythm
The researchers set out to alter the expression of genes in both groups of cells and observe the behavior of flies in bright light, darkness, or in different combinations of light and darkness. What they found was that both systems form a dual control in a group-the late-notice deals when it starts to get dark, and the other at dawn. The ads are followed by a cascade of biochemical events.
Thus, when in winter the days get shorter circadian network responds biochemically to signal change, and the same happens when the days get longer. The clock is synchronized daily to mark the seasonal change generate an immediate response to changes in the environment. But how the information enters the light changes in the cells, either morning or afternoon? According to the results of group Rosbash, takes care of that a gene called Shaggy.
Gene interesting because of its human equivalent, GSK-3, acting therapies for severe affective disorders based on lithium. Does that mean that human depression is due to disruptions in this gene? Shaggy is essential to introduce the molecular clock information on changes in ambient light, say the authors, who believes that there is probably a link between depression and circadian rhythm, "says Stoll.
"In the most severe form of seasonal affective disorder using lithium therapy, lithium is a mood stabilizer and inhibits Shaggy." The last piece of the puzzle is that exposure to specific doses of bright light is an effective treatment for seasonal affective disorders. "This paper does not explicitly examines the relationship with affective disorders, because this was not the goal. But the presence at the puzzle of all factors, it is surprising and may explain why light therapy works, "concludes Stoleru.
THE SIXTH SENSE
is already known since the eighteenth century that the agencies are governed by a clock independent internal environment: in environments without external changes, cave, greenhouses, laboratories, it is noted that both plants and animals maintain their usual period of about 24 hours, but in relation to the period of adjustment usual day / night. To have a sync with the outside must have physical pathways external light levels to the body.
This gateway to the brain is the suprachiasmatic nucleus, a structure located in the hypothalamus. This nucleus receives a signal from specialized cells in the retina and has neurons that express genes or not depending on light levels. It has been observed in mice as the destruction of the nucleus suprachiasmatic animals makes gap completely with respect to the environment, although its activity is guided by a 24-hour cycle.
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