Monday, 11 February 2008

Weekly BioNews 4 - 11 Feb 2008

- First Documented Case Of Pest Resistance To Biotech Cotton

ScienceDaily (Feb. 8, 2008)

A pest insect known as bollworm is the first to evolve resistance in the field to plants modified to produce an insecticide called Bt, according to a new research report.

Bt-resistant populations of bollworm, Helicoverpa zea, were found in more than a dozen crop fields in Mississippi and Arkansas between 2003 and 2006.

"What we're seeing is evolution in action," said lead researcher Bruce Tabashnik. "This is the first documented case of field-evolved resistance to a Bt crop."

Bt crops are so named because they have been genetically altered to produce Bt toxins, which kill some insects. The toxins are produced in nature by the widespread bacterium Bacillus thuringiensis, hence the abbreviation Bt.

Full Article

- DNA 'barcode' revealed in plants

Anna-Marie Lever Science and nature reporter, BBC News
Wednesday, 6 February 2008, 13:48 GMT

A "barcode" gene that can be used to distinguish between the majority of plant species has been identified, say scientists.

This gene can be used to catalogue plant life as it has a slightly different code between species but is nearly identical within a species.

Species that look the same to the human eye can be told apart with a small leaf sample.
DNA barcoding is already a well-established technique in animals.

The work is reported in the Proceedings of the National Academy of Sciences journal.

- Three-parent embryo formed in lab

Tuesday, 5 February 2008, 11:13 GMT

Scientists believe they have made a potential breakthrough in the treatment of serious disease by creating a human embryo with three separate parents. The Newcastle University team believe the technique could help to eradicate a whole class of hereditary diseases, including some forms of epilepsy.

The embryos have been created using DNA from a man and two women in lab tests.

It could ensure women with genetic defects do not pass the diseases on to their children.

The technique is intended to help women with diseases of the mitochondria - mini organelles that are found within individual cells.

They are sometimes described as "cellular power plants" because they generate most of the cell's energy.

Faults in the mitochondrial DNA can cause around 50 known diseases, some of which lead to disability and death.

The scientists have created the embryo in the lab
- Faulty Fountains of Youth - Adult stem cells may contribute to aging
Patrick Barry

Skin sags. Hair grays. Organs don't work quite like they used to. A gradual wearing out and running down of the body's tissues seems an inherent part of growing older. Rejuvenation of skin, muscles, and other body parts naturally declines with the passing years.

An adult blood stem cell floats amid red blood cells in this stylized illustration. Red blood cells represent one of the many specialized cell types replenished by these stem cells. Scientists are revealing a more complex picture of the relationship between adult stem cells and the aging process.

Scientifically speaking, however, this observation is much less self-evident. Some cells in a person's body can resist the tide of aging. Consider the reproductive cells a person carries that will become the cells of newborn children who have 80-plus years of life to look forward to. Generation after generation, these reproductive cells form an unbroken line stretching for millennia.
- PARP-1 rules! Cornell scientists find how a protein binds to genes and regulates human genome

February 9, 2008 04:03 PM

Out of chaos, control: Cornell University molecular biologists have discovered how a protein called PARP-1 binds to genes and regulates their expression across the human genome. Knowing where PARP-1 is located and how it works may allow scientists to target this protein while battling common human diseases.

Their research is in a study published today (Feb.8, 2008) in the journal Science. "This finding was unexpected -- especially since it entails a broad distribution of PARP-1 across the human genome and a strong correlation of the protein binding with genes being turned on," said W. Lee Kraus, Cornell associate professor in molecular biology and the corresponding author in the published study. Kraus has a dual appointment at Cornell's Weill Medical College in New York City. "Our research won't necessarily find cures for human diseases, but it provides molecular insight into the regulation of gene expression that will gives us clues where to look next."

Kraus explains that PARP-1 and another genome-binding protein called histone H1 compete for binding to gene "promoters" (the on-off switches for genes) and, as such, act as part of a control panel for the human genome. H1 puts genes in an "off" position and PARP-1 turns them "on." The new study, said Kraus, shows that for a surprising number genes, the PARP-1 protein is present and histone H1 is not, helping to keep those genes turned on.
-Tattooing improves response to DNA vaccine

February 8, 2008 12:03 PM

A tattoo can be more than just a fashion statement – it has potential medical value, according to an article published in the online open access journal, Genetic Vaccines and Therapy.

Martin Muller and his team at the Deutsches Krebsforschungszentrum (German Cancer Research Center), Heidelberg, Germany, have shown that tattooing is a more effective way of delivering DNA vaccines than intramuscular injection. Using a coat protein from the human papillomavirus (HPV, the cause of cervical cancer) as a model DNA vaccine antigen, they compared delivery by tattooing the skin of mice with standard intramuscular injection with, and without, the molecular adjuvants that are often given to boost immune response.

The tattoo method gave a stronger humoral (antibody) response and cellular response than intramuscular injection, even when adjuvants were included in the latter. Three doses of DNA vaccine given by tattooing produced at least 16 times higher antibody levels than three intramuscular injections with adjuvant. The adjuvants enhanced the effect of intramuscular injection, but not of tattooing.
- NIAID scientists identify new cellular receptor for HIV

February 10, 2008 06:37 PM

A cellular protein that helps guide immune cells to the gut has been newly identified as a target of HIV when the virus begins its assault on the body's immune system, according to researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

“The identification of this new receptor opens up new avenues of investigation that may help further elucidate the complex mechanisms of the pathogenesis of HIV infection,” says NIAID Director Anthony S. Fauci, M.D., chief of the Institute’s Laboratory of Immunoregulation (LIR) and senior author of the new study.

Several other immune cell receptors bind to HIV. Most important among these, the CD4 molecule, identified as an HIV receptor in 1984, functions as the principal receptor for HIV. The CCR5 and CXCR4 molecules, discovered in 1996, serve as co-receptors that HIV uses to enter its target cells. In the new study, which appears online Feb. 10, 2008 in Nature Immunology, NIAID scientists identify a cell adhesion molecule known as integrin alpha 4 beta 7 as another potentially important receptor for HIV.

1 comment:

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