ScienceDaily: Top Science News

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• Getting to the root of enamel evolution
• A symbiotic way of life: 'Simple and elegant mechanism' regulates relationships between insects and bacteria
• Evolution in species may reverse predator-prey population cycles
• Uncontrollable ice-melt? Uncorking East Antarctica could yield unstoppable sea-level rise, simulations show
• Bone marrow-on-a-chip unveiled
• How does stress increase risk for stroke, heart attack?
• Light-sensitive 'eyes' in plants: How phytochrome proteins tell plants whether it's day or night
• Infusion of young blood recharges brains of old mice
• Scientists reveal circuitry of fundamental motor circuit

Getting to the root of enamel evolution Posted: 05 May 2014 12:53 PM PDT Thick tooth enamel is one of the features that distinguishes our genus, Homo, from our primate relatives and forebears. A new study offers insight into exactly how evolution shaped our teeth, one gene at a time. By comparing the human genome with those of five other primate species, a team of geneticists and evolutionary anthropologists has identified two segments of DNA where natural selection acted to give modern humans their thick enamel.

A symbiotic way of life: 'Simple and elegant mechanism' regulates relationships between insects and bacteria Posted: 05 May 2014 12:53 PM PDT Scientists reveal how, at the cellular level, an animal and its symbiotic bacteria work together to make up a single organismal system.

Evolution in species may reverse predator-prey population cycles Posted: 05 May 2014 12:51 PM PDT Populations of predators and their prey usually follow predictable cycles. When the number of prey increases -- perhaps as their food supply becomes more abundant -- predator populations also grow. When the predator population becomes too large, however, the prey population often plummets, leaving too little food for the predators, whose population also then crashes. Co-evolutionary changes in species may reverse traditional predator-prey population cycles, creating the appearance that prey are eating the predators, according to a new study.

Uncontrollable ice-melt? Uncorking East Antarctica could yield unstoppable sea-level rise, simulations show Posted: 05 May 2014 07:44 AM PDT The melting of a rather small ice volume on East Antarctica's shore could trigger a persistent ice discharge into the ocean, resulting in unstoppable sea-level rise for thousands of years to come. These findings are based on computer simulations of the Antarctic ice flow using improved data of the ground profile underneath the ice sheet.

Bone marrow-on-a-chip unveiled Posted: 05 May 2014 07:44 AM PDT The first method to reproduce the structure, functions and cellular make-up of bone marrow in the laboratory has been unveiled by researchers. The new device gives scientists a much-needed new method to test the effects on bone marrow of toxic agents and new drugs to prevent lethal radiation poisoning and dangerous side effects of cancer therapies, all without animal testing.

How does stress increase risk for stroke, heart attack? Posted: 05 May 2014 07:44 AM PDT Scientists have shown that anger, anxiety, and depression not only affect the functioning of the heart, but also increase the risk for heart disease. Stroke and heart attacks are the end products of progressive damage to blood vessels supplying the heart and brain, a process called atherosclerosis. Atherosclerosis progresses when there are high levels of chemicals in the body called pro-inflammatory cytokines. It is thought that persisting stress increases the risk for atherosclerosis and cardiovascular disease by evoking negative emotions that, in turn, raise the levels of pro-inflammatory chemicals in the body.

Light-sensitive 'eyes' in plants: How phytochrome proteins tell plants whether it's day or night Posted: 05 May 2014 07:42 AM PDT Most plants try to turn towards the sun. Scientists now have a better understanding of how light-sensitive proteins in plant cells change when they are exposed to light. The family of proteins involved is known as the "phytochrome" family, and these proteins are found in all plant leaves. These proteins detect the presence of light and inform the cell whether it is day or night, or whether the plant is in the shade or the sun.

Infusion of young blood recharges brains of old mice Posted: 05 May 2014 06:49 AM PDT Something -- or some things -- in the blood of young mice has the ability to restore mental capabilities in old mice, a new study has found. If the same goes for humans, it could spell a new paradigm for recharging our aging brains, and it might mean new therapeutic approaches for treating dementias such as Alzheimer's disease.

Scientists reveal circuitry of fundamental motor circuit Posted: 02 May 2014 02:19 PM PDT The developmental source for a key type of neuron that allows animals to walk, a finding that could help pave the way for new therapies for spinal cord injuries or other motor impairments related to disease. The spinal cord contains a network of neurons that are able to operate largely in an autonomous manner, thus allowing animals to carry out simple rhythmic walking movements with minimal attention—giving us the ability, for example, to walk while talking on the phone. These circuits control properties such as stepping with each foot or pacing the tempo of walking or running.

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