Biology

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Endocrine glands and hormones

Endocrine glands lack ducts and are hence, called ductless glands. Their secretions are called hormones. The classical definition of hormone as a chemical produced by endocrine glands and released into the blood and transported to a distantly located target organ has current scientific definition as follows: Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts. The new definition covers a number of new molecules in addition to the hormones secreted by the organised endocrine glands. Invertebrates possess very simple endocrine systems with few hormones whereas a large number of chemicals act as hormones and provide coordination in the vertebrates.

Novel Approach for Single Molecule Electronic DNA Sequencing

DNA sequencing is the driving force behind key discoveries in medicine and biology. For instance, the complete sequence of an individual's genome provides important markers and guidelines for medical diagnostics and healthcare. Up to now, the major roadblock has been the cost and speed of obtaining highly accurate DNA sequences. While numerous advances have been made in the last 10 years, most current high-throughput sequencing instruments depend on optical techniques for the detection of the four building blocks of DNA: A, C, G and T. To further advance the measurement capability, electronic DNA sequencing of an ensemble of DNA templates has also been developed.

Rapid Coral Death by a Deadly Chain Reaction

Most people are fascinated by the colorful and exotic coral reefs, which form habitats with probably the largest biodiversity. But human civilization is the top danger to these fragile ecosystems through climate change, oxygen depletion and ocean acidification. Industrialization, deforestation and intensive farming in coastal areas are changing dramatically the conditions for life in the oceans. Now scientists at the Max Planck Institute for Marine Microbiology from Bremen together with their colleagues from Australia, Sultanate of Oman and Italy have investigated how and why the corals die when exposed to sedimentation. According to their findings, oxygen depletion, together with an acidification of the environment, creates a chain reaction that leads to coral death.

Naked Mole-Rats May Hold Clues to Pain Relief

Naked mole-rats evolved to thrive in an acidic environment that other mammals, including humans, would find intolerable. Researchers at the University of Illinois at Chicago report new findings as to how these rodents have adapted to this environment.

DNA Analysis Aids in Classifying Single-Celled Algae

For nearly 260 years -- since Carl Linnaeus developed his system of naming plants and animals -- researchers classified species based on visual attributes like color, shape and size. In the past few decades, researchers found that sequencing DNA can more accurately identify species. A group of single-celled algae -- Symbiodinium -- that live inside corals and are critical to their survival -- are only now being separated into species using DNA analysis, according to biologists. "Unfortunately with Symbiodinium , scientists have been hindered by a traditional morphology-based system of species identification that doesn't work because these organisms all pretty much look the same -- small round brown cells," said Todd LaJeunesse, assistant professor of biology at Penn State. "This delay in adopting the more accurate convention of identifying species using genetic techniques has greatly impeded progress in the research of symbiotic reef-building corals, especially ...

Cell Death Discovery Suggests New Ways to Protect Female Fertility

Melbourne researchers have identified a new way of protecting female fertility, offering hope to women whose fertility may be compromised by the side-effects of cancer therapy or by premature menopause. The researchers, from the Walter and Eliza Hall Institute, Monash University and Prince Henry's Institute of Medical Research, made the discovery while investigating how egg cells die. They found that two specific proteins, called PUMA and NOXA, cause the death of egg cells in the ovaries. The finding may lead to new strategies that protect women's fertility by blocking the activity of these two proteins. Associate Professor Clare Scott from the Walter and Eliza Hall Institute said the research showed that when the DNA of egg cells is damaged following exposure to radiation or chemotherapy, such as that received during some cancer treatments, PUMA and NOXA trigger the death of the damaged eggs. This egg cell death causes many female cancer patients to become infertile. ...