Genetics & Molecular Biology
Two women who took part in the world's first controlled study of a genetic screening test before IVF have given birth to healthy babies.
The babies are the first deliveries in a pilot study of comparative genomic hybridization (CGH) by microarray, a new method of screening oocytes, female gametocytes involved in reproduction, before in vitro fertilization (IVF) for a full range of chromosomal disorders.
The smallest entity of life is the single cell, which exists not only as single cell organisms, but as evolution proceeds, as members of a bigger and more complex living organism. During the progression of life, an organism encounters many experiences, and encodes these experiences as memories or knowledge.
Ever wonder what the smallest protein is? Apparently it's TRP-Cage, a protein with only 20 amino acids derived from the saliva of Gila monsters.
Trp-cage - smallest protein
You can find the structure file and images in the PDB database (www.pdb.org
) with PDB ID = 1L2Y. This highly stable mini-protein is important for studies of protein stability, protein folding, and 3D structure.
Even with this small size, it displays secondary structural elements, such as an alpha helix, found in many proteins. So far there are no known proteins with less than 20 residues, but we'll see what happens in the future.
The longest human protein is Titin with 34,350 amino acids. The smallest human protein is 44 amino acids but it could be an abortive translation from the 5' UTR of another mRNA. The smallest functional polypeptide is glutathione with only three amino acids.
BTW, proline is technically not even an amino acid much less a polypeptide. Chignolin is a man-made decapeptide so if you synthesize a GG dipeptide, it would be the smallest possible amino acid polymer.
Scientists have altered cardiac muscle cells to make them controllable with light and showed an ability to cause conditions such as arrhythmia in genetically modified mice, which opens up new possibilities for researching the development and therefore treatment of arrhythmias.
Tobias Brügmann and his colleagues from the University of Bonn’s Institute of Physiology I used a “channelrhodopsin” for their experiments - a type of light sensor. At the same time, it can act as an ion channel in the cell membrane because when stimulated with blue light, this channel opens, and positive ions flow into the cell. This causes a change in the cell membrane’s pressure, which stimulates cardiac muscle cells to contract.
Stem cells help regenerate or repair damaged tissues, primarily by releasing growth factors that encourage existing cells in the human body to function and grow.
There has been an ongoing ethical controversy about human embryonic stem cell research but progress has been made nicely using adult stem cells, such as from marrow donors.
Proteins are the heavy lifters of cells, doing numerous tasks, but how the shape of a protein determines function remains one of the most important questions in the physics of biology.
Proteins are not the static, Lego-like objects you might see in an x-ray photograph in a textbook, they are made from long chains of amino acids scrunched into various blobs and a protein is always changing to slightly different structural arrangements due to thermal motion of its atoms. Even a modest-sized protein like myoglobin has an unimaginable number of possible arrangements of its atoms and each of these arrangements slightly changes its function.
We accept that genetics make some people smarter though few consider instead that genes may be making us dumber, but deleting the RGS14 gene in mice did make them smarter - by unlocking a mysterious region of the brain considered to be relatively inflexible, scientists at Emory University School of Medicine have found.
Bring on the psychic fans!
Premature ovarian failure (POF) is when a woman's ovaries stop working before she is 40. Missed periods are usually the first sign of POF. Later symptoms may be similar to those of natural menopause.
Most women with POF cannot get pregnant naturally. Fertility treatments help a few women; others use donor eggs to have children. There is no treatment that will restore normal ovarian function, though many health care providers suggest taking hormones until age 50. According to the International Premature Ovarian Failure Association
, between 1 and 4% of women suffer from POF – equivalent to between 250,000 and 1 million women in the USA alone.
Researchers say they have found 13 genes linked to human body mass.
Starting with DNA samples extracted from Icelanders' white blood cells banked in 1991 and 2002 by scientists there as part of the AGES–Reykjavik study of individuals in the general population, scientists used a customized, genome-wide profiling method dubbed CHARM (comprehensive high-throughput arrays for relative methylation) to look for regions that were the most variable, all chemically marked by DNA methylation.
The DNA methylation analyses revealed epigenetic fingerprints which are unique to each individual and remain stable over time and may also be associated with various common traits including risks for common, complex diseases such as cancer and other conditions.