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Sleep loss affects immune system

Researchers have identified the genes that are most susceptible to sleep deprivation and are examining if these genes are involved in the regulation of the immune system.

Conducted at the sleep laboratory of the Finnish Institute of Occupational Health, the study restricted the amount of sleep of a group of healthy young men to four hours per night for five days, imitating the schedule of a normal working week.

Blood samples were taken before and after the sleep deprivation test. White blood cells were isolated from the samples, and the expression of all genes at the time of the sampling was examined using microarrays.

The results were compared with samples from healthy men of comparable age who had been sleeping eight hours per night for the week.

Researcher Vilma Aho said that they compared the gene expression before and after the sleep deprivation period, and focused on the genes whose behaviour was most strongly altered.

Sweat glands can help heal skin injuries

A team of researchers have determined that under certain conditions, the sweat gland stem cells could heal skin wounds.

They have claimed that the glands can also help regenerate all layers of the epidermis.
USC faculty member Krzysztof Kobielak and his team used a system to make all of the sweat gland cells in a mouse easy to spot: labeling them with green fluorescent protein (GFP), which is visible under ultraviolet light.

Over time, the GFP became dimmer as it was diluted among dividing sweat gland cells. After four weeks, the only cells that remained fluorescent were the ones that did not divide or divided very slowly — a known property among stem cells of certain tissues, including the hair follicle and cornea.

Therefore, these slow-dividing, fluorescent cells in the sweat gland’s coiled lower region were likely also stem cells.

Then, the first author of this paper, graduate student Yvonne Leung, tested whether these fluorescent cells could do what stem cells do best — differentiate into multiple cell types.

To the researchers’ surprise, these glowing cells generated not only sweat glands, but also hair follicles when placed in the skin of a mouse without GFP.
 
Chimpanzees use long-term memory to forage for food

A team of scientists have determined that chimpanzees use long-term memory for remembering the size and location of fruit trees and feeding experiences from previous seasons using a memory window that can be from two months to three years ago.

The team, led by Karline Janmaat from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, recorded the behaviour of five chimpanzee females for continuous periods of four to eight weeks, totalling 275 complete days, throughout multiple fruiting seasons in the Tai National Park, Cote d’Ivoire.

They found that chimpanzees fed on significantly larger trees than other reproductively mature trees of the same species, especially if their fruits emitted an obvious smell.
Interestingly, trees that were merely checked for edible fruit, but where monitoring could not have been triggered by smell, or the sound of fallen fruit, because the trees did not carry fruit, were also larger.

The researchers found that chimpanzees checked most trees along the way during travel, but 13 percent were approached in a goal-directed manner.

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