BEIJING,April 8(Xinhuanet) -- Surprises abound in the journey of life. And the beginning is especially wonderful.
Knock, knock -- the shell cracks; then a naughty, curious miniature gets out from the broken egg, making its appearance in the world for the very first time.
Following sets of pictures show the young of four different species hatching from their eggs. These extraordinary photos are created by the couple team Heidi and Hans-Juergen Koch from Germany (who have specialized in animal photography for the past 20 years). Let's say hello to those fascinating little lives! Ostrich
ScienceDaily (Apr. 6, 2010) — Performance of an hour or more of physical activity per day by adolescents is associated with control of body weight even among those who are genetically predisposed to obesity, according to a report in the April issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.
"There is compelling evidence that human obesity is a multifactorial disorder where both genes and lifestyle factors, including diet and physical activity, are important contributors," the authors write as background information in the article. "Among the obesity-related genes, polymorphisms in the fat mass- and obesity-associated gene (FTO) are strongly associated with body fat estimates in populations of different ethnic background or ages." Each copy of a mutation in this gene may be associated with a weight increase of approximately 1.5 kilograms or 3.3 pounds.
The U.S. Department of Health and Human Services recently released updated guidelines recommending that children and adolescents participate in physical activity for 60 minutes per day or longer, with most exercise being of moderate to vigorous intensity. To see if this level of physical activity reduces the effects of mutations in the FTO gene on body fat, Jonatan R. Ruiz, Ph.D., of the Karolinska Institutet, Huddinge, Sweden, and colleagues studied 752 adolescents who were part of a cross-sectional study in 10 European countries between October 2006 and December 2007.
Of the participating teens, 275 (37 percent) had no copies of the obesity mutation, 354 (47 percent) had one copy and 123 (16 percent) had two copies. The mutation was associated with a higher body mass index (BMI), higher body fat percentage and a larger waist circumference.
However, among participants who met the daily physical activity recommendations, the effect of the gene mutation was much lower. For each copy of the mutated gene, those who exercised as recommended had a BMI an average of 0.17 higher than those with no mutations, compared with 0.65 higher per mutation among those who did not meet exercise requirements. Similarly, each mutated gene was associated with an increase of 0.4 percent in body fat and a 0.6-centimeter increase in waist circumference among those who met activity guidelines, compared with a 1.7 percent increase in body fat and a 1.15 centimeter increase in waist circumference among those who did not.
"These findings have important public health implications and indicate that meeting the physical activity recommendations may offset the genetic predisposition to obesity associated with the FTO polymorphism in adolescents," the authors write. "Indeed, adolescents meeting the daily physical activity recommendations may overcome the effect of this gene on obesity-related traits."
ScienceDaily (Apr. 6, 2010) — Depression and schizophrenia can be triggered by environmental stimuli and often occur in response to stressful life events. However, some people have a higher predisposition to develop these diseases, which highlights a role for genetics in determining a person's disease risk.
A high number of people with depression have a genetic change that alters a protein that cells use to talk to each other in the brain. Imaging of people with depression also shows that they have greater activity in some areas of their brain. Unfortunately, the techniques that are currently available have not been able to determine why stress induces pathological changes for some people and how their genetics contribute to disease.
A new mouse model may provide some clues about what makes some people more likely to develop depression after experiencing stress. A collaborative group of European researchers created a mouse that carries a genetic change associated with depression in people. "This model has good validity for understanding depression in the human, in particularly in cases of stress-induced depression, which is a fairly widespread phenomenon" says Dr. Alessandro Bartolomucci, the first author of the research published in the journal, Disease Models and Mechanisms (DMM).
The scientists made genetic changes in the transporter that moves a signaling protein, serotonin, out of the communication space between neurons in the brain. The changes they made are reminiscent of the genetic changes found in people who have a high risk of developing depression.
"There is a clear relationship between a short form of the serotonin transporter and a very high vulnerability to develop clinical depression when people are exposed to increasing levels of stressful life events." says Dr. Bartolomucci, "This is one of the first studies performed in mice that only have about 50% of the normal activity of the transporter relative to normal mice, which is exactly the situation that is present in humans with high vulnerability to depression."
Mice with the genetic change were more likely to develop characteristics of depression and social anxiety, which researchers measure by their degree of activity and their response to meeting new mice. The work from this study now allows researchers to link the genetic changes that are present in humans with decreased serotonin turnover in the brain. It suggests that the genetic mutation impedes the removal of signaling protein from communication areas in the brain, which may result in an exaggerated response to stress.
Dr. Bartolomucci points out that many of the chemical changes they measured occurred in the areas of the brain that regulate memory formation, emotional responses to stimuli and social interactions, which might be expected. "What we were surprised by was the magnitude of vulnerability that we observed in mice with the genetic mutation and the selectivity of its effects."
