Tuesday, 8 April 2008

Weekly BioNews 31 Mar - 7 Apr 2008




- Is DNA Repair A Substitute For Sex?


ScienceDaily (Apr. 4, 2008)

Birds and bees may do it, but the microscopic animals called bdelloid rotifers seem to get along just fine without sex, thank you. What’s more, they have done so over millions of years of evolution, resulting in at least 370 species. These hardy creatures somehow escape the usual drawback of asexuality – extinction – and the MBL’s David Mark Welch, Matthew Meselson, and their colleagues are finding out how.

In two related papers published recently in Proceedings of the National Academy of Sciences (PNAS), the team proposes an interesting hypothesis: Bdelloid rotifers have been able to give up sex and survive because they have evolved an extraordinary efficient mechanism for repairing harmful mutations to their DNA.


- DNA Building Block Creation Seen In Living Cells: Could Be Key To New Cancer Treatments

ScienceDaily (Apr. 4, 2008)

Penn State scientists are the first to observe in living cells a key step in the creation of adenine and guanine, two of the four building blocks that comprise DNA. Also called purines, the two building blocks are essential for cell replication. The findings, which will be published in the 4 April 2008 issue of the journal Science, could lead to new cancer treatments that prevent cancer cells from replicating by interfering with their abilities to make purines.

The group used cervical cancer cells--which have an increased demand for purines due to their rapid rates of replication--to demonstrate that a group of six enzymes is involved in the creation of purines. "Our research shows that these enzymes form a cluster prior to purine formation," said Erin Sheets, an assistant professor of chemistry and a collaborator on the project.

- Plants Grow Spindly When Reaching For Sunlight: Now Researchers Understand How

ScienceDaily (Apr. 3, 2008)

Those spindly plants that desperately try to reach for a break in the canopy formed by larger plants all suffer from the same affliction: Shade avoidance syndrome or SAS. Now, the molecular details of SAS have been brought to light by researchers at the Salk Institute for Biological Studies

To step out of their neighbors' shade, plants switch on a natural chemical factory for the synthesis of the plant growth hormone auxin that lets a plant grow and ultimately stretch toward the sun, the Salk researchers report in an article published in the April 4, 2008 issue of the journal Cell. Understanding this response at a molecular level will allow scientists to naturally manipulate this response to increase yield in crops ranging from rice to wheat.

- Visualizing The Machinery Of mRNA Splicing

ScienceDaily (Apr. 4, 2008)

Recent research at Yale provided a glimpse of the ancient mechanism that helped diversify our genomes; it illuminated a relationship between gene processing in humans and the most primitive organisms by creating the first crystal structure of a crucial self-splicing region of RNA.
Genes of higher organisms code for production of proteins through intermediary RNA molecules. But, after transcription from the DNA, these RNAs must be cut into pieces and patched together before they are ready for translation into protein. Stretches of the RNA sequence that code for protein are kept, and the intervening sequences, or introns, are spliced out of the transcript.

Ribbon reconstruction view of the crystal structure of an RNA group II intron -- red domain is the active site.


http://www.sciencedaily.com/releases/2008/04/080404181914.htm


- As nanotech goes mainstream, 'toxic socks' raise concerns


April 6, 2008 11:10 PM


Nanotechnology is now available in a store near you. Valued for it’s antibacterial and odor-fighting properties, nanoparticle silver is becoming the star attraction in a range of products from socks to bandages to washing machines. But as silver’s benefits propel it to the forefront of consumer nanomaterials, scientists are recommending a closer examination of the unforeseen environmental and health consequences of nanosilver.


“The general public needs to be aware that there are unknown risks associated with the products they buy containing nanomaterials,” researchers Paul Westerhoff and Troy M. Benn said in a report scheduled for the 235th national meeting of the American Chemical Society (ACS).


Westerhoff and Benn report that ordinary laundering can wash off substantial amounts of the nanosilver particles from socks impregnated with the material. The Arizona State researchers suggest that the particles, intended to prevent foot odor, could travel through a wastewater treatment system and enter natural waterways where they might have unwanted effects on aquatic organisms living in the water and possibly humans, too.


http://www.biologynews.net/archives/2008/04/06/as_nanotech_goes_mainstream_toxic_socks_raise_concerns.html


- 'Healing clays' show promise for fighting deadly MRSA superbug infections, other diseases


April 6, 2008 11:10 PM


Mud may be coming to a medicine cabinet or pharmacy near you. Scientists in Arizona report that minerals from clay could form the basis of a new generation of inexpensive, highly-effective antimicrobials for fighting MRSA infections that are moving out of health care settings and into the community. These “superbugs” are increasingly resistant to multiple antibiotics and cause thousands of deaths each year.


Unlike conventional antibiotics that are often administered by injection or pills, the so-called “healing clays” could be used as rub-on creams or ointments to keep MRSA infections from spreading, the researchers say. The clays also show promise against a wide range of other harmful bacteria, including those that cause skin infections and food poisoning, the scientists add. Their study, one of the first to explore the antimicrobial activity of natural clays in detail, was presented today at the 235th national meeting of the American Chemical Society.


Clays have been used for thousands of years as a remedy for infected wounds, indigestion, and other health problems, either by applying clay to the skin or eating it. Today, clays are commonly used at health spas in the form of mud baths and facials. Armed with new investigative tools, researchers are beginning to explore their health claims scientifically.


http://www.biologynews.net/archives/2008/04/06/healing_clays_show_promise_for_fighting_deadly_mrsa_superbug_infections_other_diseases.html


- New chapter in the history of rice research opens


April 4, 2008 09:21 PM


A major new partnership between the public and private sectors was made official here this week (3-4 April) with an aim to increase rice production across Asia via the accelerated development and introduction of hybrid rice technologies. The innovative new effort to increase rice production – and support for rice research – comes at a crucial time for Asia as the region struggles to deal with near record rice prices caused by stagnating yields.


Robert Zeigler, director general of the International Rice Research (IRRI), which convened and hosted this inaugural meeting of the Hybrid Rice Research and Development Consortium (HRDC), said during the opening session that there is no question this meeting represents the first pages of an entirely new chapter in the history of rice research. “Certainly, the success of hybrid rice in China is well known,” added Dr. Zeigler, “and the potential for hybrid rice to have an impact across the rest of the rice-growing world is something that we all believe is real.”


IRRI and its partners in the public and private sectors have led research, development, and use of hybrid rice technology in the tropics for almost 30 years. Hybrid rice varieties have the potential to raise the yield of rice and thus overall rice productivity and profitability in Asia. Successful deployment of hybrid rice, however, requires a more effective cooperation between public research institutions and private sector companies to study ways to overcome the current constraints.


http://www.biologynews.net/archives/2008/04/04/new_chapter_in_the_history_of_rice_research_opens.html


- Promising new nanotechnology for spinal cord injury


April 3, 2008 10:05 AM


A spinal cord injury often leads to permanent paralysis and loss of sensation below the site of the injury because the damaged nerve fibers can't regenerate. The nerve fibers or axons have the capacity to grow again, but don’t because they're blocked by scar tissue that develops around the injury.


Northwestern University researchers have shown that a new nano-engineered gel inhibits the formation of scar tissue at the injury site and enables the severed spinal cord fibers to regenerate and grow. The gel is injected as a liquid into the spinal cord and self -assembles into a scaffold that supports the new nerve fibers as they grow up and down the spinal cord, penetrating the site of the injury.


When the gel was injected into mice with a spinal cord injury, after six weeks the animals had a greatly enhanced ability to use their hind legs and walk.


http://www.biologynews.net/archives/2008/04/03/promising_new_nanotechnology_for_spinal_cord_injury.html

- Nano-sized technology has super-sized effect on tumors


April 2, 2008 08:05 PM


Anyone facing chemotherapy would welcome an advance promising to dramatically reduce their dose of these often harsh drugs. Using nanotechnology, researchers at Washington University School of Medicine in St. Louis have taken a step closer to that goal.


The researchers focused a powerful drug directly on tumors in rabbits using drug-coated nanoparticles. They found that a drug dose 1,000 times lower than used previously for this purpose markedly slowed tumor growth.


"Many chemotherapeutic drugs have unwanted side effects, and we've shown that our nanoparticle technology has the potential to increase drug effectiveness and decrease drug dose to alleviate harmful side effects," says lead author Patrick M. Winter, Ph.D., research assistant professor of medicine and biomedical engineering.


http://www.biologynews.net/archives/2008/04/02/nanosized_technology_has_supersized_effect_on_tumors.html

- Nano-softball made of DNA


April 1, 2008 08:52 PM


For quite some time, DNA, the stuff our genes are made of, has also been considered the building material of choice for nanoscale objects. A team led by G√ľnter von Kiedrowski at the Ruhr University in Bochum has now made a dodecahedron (a geometric shape with twelve surfaces) from DNA building blocks. As reported in the journal Angewandte Chemie, these objects are formed in a self-assembly process from 20 individual trisoligonucleotides, building blocks consisting of a “branching junction” and three short DNA strands.

Can 20 trisoligonucleotides with 20×3 individual sequences be programmed to self-assemble into a DNA dodecahedron? The answer is yes if one starts from a new generation of trisoligonucleotides based on C3h-symmetric linkers with proper flexibility. The resulting dodecahedron has C1 symmetry and may facilitate the construction of multimodular scaffolds in the future.


A regular dodecahedron is a geometric shape made of 12 pentagons of equal size, three of which are connected at every vertex. This results in a structure with 30 edges and 20 vertices. In order to produce a hollow dodecahedral object from DNA, the researchers used 20 “three-legged” building blocks (three DNA strands connected together at one point). The centers of these building blocks represent the vertices of the dodecahedron. The three edges projecting from each vertex are formed when a single strand of DNA converts two neighboring bridging components into a double strand.

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