Monday, 5 May 2008

Weekly BioNews 28 Apr - 05 May 2008

- Scientists Discover Why Plague Is So Lethal

ScienceDaily (May 4, 2008)

Bacteria that cause the bubonic plague may be more virulent than their close relatives because of a single genetic mutation, according to research published in the May issue of the journal Microbiology.

"The plague bacterium Yersinia pestis needs calcium in order to grow at body temperature. When there is no calcium available, it produces a large amount of an amino acid called aspartic acid," said Professor Brubaker from the University of Chicago, USA. "We found that this is because Y. pestis is missing an important enzyme."

Bubonic plague has killed over 200 million people during the course of history and is thus the most devastating acute infectious disease known to man. Despite this, we are still uncertain about the molecular basis of its extraordinary virulence.

"Y. pestis evolved from its ancestor Y. pseudotuberculosis within the last 20,000 years, suggesting its high lethality reflects only a few genetic changes. We discovered that a single mutation in the genome of Y. pestis means the enzyme aspartase is not produced," said Professor Brubaker.

Aspartase is present in almost all bacteria but it is curiously absent in many pathogenic types. These include mycobacteria that are pathogenic to man, Francisella tularensis and rickettsiae (both of which cause diseases transmitted to humans via insects). "This suggests that the absence of aspartase may contribute to serious disease," said Professor Brubaker......

- Getting Wise To Influenza Virus' Tricks: Imaging Of Influenza Virus Protein Opens Way To Design New Anti-viral Drugs

ScienceDaily (May 4, 2008)

Influenza is currently a grave concern for governments and health organisations around the world. The worry is the potential for highly virulent bird flu strains, such as H5N1, to develop the ability to infect humans easily. New drugs and vaccines to halt the spread of the virus are badly needed. Now one of the tactics used by influenza virus to take over the machinery of infected cells has been laid bare by structural biologists at the European Molecular Biology Laboratory (EMBL) and the joint Unit of Virus Host-Cell Interaction of EMBL, the University Joseph Fourier and National Centre for Scientific Research (CNRS), in Grenoble, France.

In the current issue of Nature Structural and Molecular Biology they publish a high-resolution image of a key protein domain whose function is to allow the virus to multiply by hijacking the host cell protein production machinery. The findings open the way for the design of new drugs to combat future influenza pandemics.

Upon infection the influenza virus starts multiplying in the cells of its host. One protein that is crucial in this process is the viral polymerase - the enzyme that copies its genetic material and helps to produce more viruses. One component of the polymerase, called PB2, plays a key role in stealing an important tag from host cell RNA molecules to direct the protein production machinery towards the synthesis of viral proteins. Researchers of the groups of Stephen Cusack and Darren Hart at EMBL Grenoble have identified the PB2 domain responsible for binding the tag, produced crystals of it and examined them with the powerful X-ray beams of the European Synchrotron Radiation Facility (ESRF)....

The high-resolution image of the influenza virus' PB2 protein shows how the virus steals a 'cap' molecule from its host to take over the protein production machinery and multiply. PB2 binds the cap (purple) by sandwiching it between aromatic amino acids. (Credit: Image courtesy of European Molecular Biology Laboratory).

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- Japanese Mushroom Leads To Breakthrough In Protein Research

ScienceDaily (May 3, 2008)

Using an enzyme of the Japanese mushroom Grifola frondosa (Maitake or dancing mushroom), proteins can be identified without knowing the organism's genetic composition. This advance simplifies the study of proteins lying at the root of such diseases as cancer and diabetes. Utrecht University Prof. Albert Heck's research group announced this breakthrough on the website of the journal Nature Methods.

Proteins play a critical role in disease and growth processes of humans, animals and plants. Identification was previously only possible when the genetic composition of the organism in question was known. Thanks to Heck's discovery, this is now a thing of the past. Heck used an enzyme from the Japanese mushroom Grifola frondosa to identify proteins.

This makes it possible to study the proteins of an organism of which the genetic composition is – as yet – unknown (e.g. exotic animal species). In addition, research into proteins responsible for such diseases as cancer and diabetes, which usually undergo modification as a result, is much more effective....

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- Stem Cells At Root Of Antlers' Branching

ScienceDaily (May 1, 2008)

The ability to regenerate lost body parts is unevenly distributed among higher organisms. Among vertebrates, some amphibians are able to replace lost limbs completely, while mammals are unable to regenerate complex appendages. The only exception to this rule is the annual replacement of deer antlers. The annual regrowth of these structures is the only example of regeneration of a complete, anatomically complex appendage in a mammal, and antlers are therefore of high interest to regeneration biologists.

The epimorphic regeneration of appendages may involve progenitor cells created through reprogramming of differentiated cells or through the activation of resident stem cells. Reporting in this week's PLoS ONE in a study funded by the German Research Society, Hans J. Rolf and colleagues from the University of Goettingen and University of Hildesheim (Germany) emphasize that deer antler growth and regeneration might be reduced to a stem cell-based process. Their results strongly support the view that the growth of primary antlers as well as the annual process of antler regeneration depend on the periodic activation of mesenchymal stem cells. Understanding the mechanisms behind this unique regeneration process could have an important impact on the emerging field of regenerative medicine...

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- Researchers report the cloning of a key group of human genes, the protein kinases

May 2, 2008 09:38 PM

Although the human genome has been sequenced, research into mechanism of action of genes has been hampered by the fact that most human genes have not been isolated. This is true for even the most common class of cancer-associated genes, the protein kinases, which mediate the majority of signaling events in cells by phosphorylating and modulating the activity of other proteins. It has been estimated by systematic gene sequencing efforts that up to a quarter of kinases may play a role in human cancers.

In a study published in the 2nd of May issue of Cell, a research teams led by Professor Jussi Taipale from the National Public Health Institute and University of Helsinki, Finland, Professor Olli Kallioniemi from Institute for Molecular Medicine Finland (FIMM), and Dr. Wei-Wu He from the US-based biotechnology company Origene Technologies, Inc., report cloning of nearly all predicted human protein kinase genes in functional form, and generation of a corresponding set of kinases lacking catalytic activity that are necessary for functional studies. They further used the kinome collection in several high-throughput screens, including a screen which identified two novel kinases regulating the Hedgehog signaling pathway – a key pathway linked to multiple types of human cancer. In addition, together with the group of Dr. Päivi Ojala, University of Helsinki, they identified a novel kinase required for activation of Kaposi’s sarcoma herpesvirus.....

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- Turning fungus into fuel

May 4, 2008 09:48 PM

A spidery fungus with a voracious appetite for military uniforms and canvas tents could hold the key to improvements in the production of biofuels, a team of government, academic and industry researchers has announced.

In a paper published today in Nature Biotechnology, researchers led by Los Alamos National Laboratory and the U.S. Department of Energy Joint Genome Institute announced that the genetic sequence of the fungus Tricoderma reesei has uncovered important clues about how the organism breaks down plant fibers into simple sugars. The finding could unlock possibilities for industrial processes that can more efficiently and cost effectively convert corn, switchgrass and even cellulose-based municipal waste into ethanol. Ethanol from waste products is a more-carbon-neutral alternative to gasoline.

The fungus T. reesei rose to dubious fame during World War II when military leaders discovered it was responsible for rapid deterioration of clothing and tents in the South Pacific. Named after Dr. Elwyn T. Reese, who, with colleagues, originally isolated the hungry fungus, T. reesei was later identified as a source of industrial enzymes and a role model for the conversion of cellulose and hemicellulose—plant fibers—into simple sugars....

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- Boost for 'green plastics' from plants

April 29, 2008 09:18 PM

Australian researchers are a step closer to turning plants into ‘biofactories’ capable of producing oils which can be used to replace petrochemicals used to manufacture a range of products.

Scientists working within the joint CSIRO/Grains Research and Development Corporation Crop Biofactories Initiative (CBI) have achieved a major advance by accumulating 30 per cent of an unusual fatty acid (UFA) in the model plant, Arabidopsis.

UFAs are usually sourced from petrochemicals to produce plastics, paints and cosmetics. CBI is developing new technologies for making a range of UFAs in oilseeds, to provide Australia with a head start in the emerging ‘bioeconomy’.

“Using crops as biofactories has many advantages, beyond the replacement of dwindling petrochemical resources,” says the leader of the crop development team, CSIRO’s Dr Allan Green. “Global challenges such as population growth, climate change and the switch from non-renewable resources are opening up many more opportunities for bio-based products.”...

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