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August 2, 2010, 6:58 AM CT

Mining bacterial genomes

Mining bacterial genomes
new tool to excavate bacterial genomes that potentially hide a rich array of pharmaceutical treasures has led to the discovery of a novel antibiotic. The study, published in the recent issue of Microbiology, could lead to new therapys for serious diseases that are rapidly acquiring multi-drug resistance.

Researchers from the University of Groningen in The Netherlands successfully used a 'genome mining' approach to find and activate a group of genes in the bacterium Streptomyces coelicolor This resulted in the production of a new antibacterial compound that was effective against several bacterial strains, including Escherichia coli.

Streptomyces is a common soil bacterium that is well-known for its antibiotic-producing capabilities. In 2002, genomic sequencing of one Streptomyces species, S. coelicolor, revealed several groups of genes whose function was unknown. By digging deeper and removing a molecule that specifically inactivates one of the mystery gene groups, known as cpk, the scientists in this study were able to 'awaken' the genes, to find that they produced the new antibiotic, in addition to a bright yellow pigment.

This is the first time a genome mining approach to drug discovery has been successfully used in Streptomyces. "The strategy is a powerful and innovative way of searching for new antibiotic production capabilities in bacteria," said Dr Eriko Takano who led the study. "As bacterial infections previously considered as mild and easily curable are suddenly becoming lethal and completely unresponsive to all existing medication, it is crucial that new antibiotics are discovered at a sufficiently rapid rate," she said.........

Posted by: Mark      Read more         Source


August 2, 2010, 6:30 AM CT

How cancer-causing bacterium works?

How cancer-causing bacterium works?
A protein produced by some strains of H. pylori interacts with a host tumor suppressor protein. This leads to degradation of the tumor suppressor protein, researchers found.

Credit: Yutaka Tsutsumi, M.D. Professor Department of Pathology Fujita Health University School of Medicine
Scientists have discovered a mechanism by which Helicobacter pylori, the only known cancer-causing bacterium, disables a tumor suppressor protein in host cells.

The newly released study, in the journal Oncogene, reports the discovery of a previously unknown mechanism linking H. pylori infection and stomach cancer, the second leading cause of cancer deaths worldwide.

About two-thirds of the world's population is infected with H. pylori, a bacterium that can survive in the harsh environment of the stomach. Most infected people never develop disease. For a significant minority, however, infection with H. pylori leads to inflammation, ulcers and in some cases, stomach (gastric) cancer.

H. pylori's ability to cause disease is closely linked to a virulence protein called CagA. Prior studies have observed that CagA-positive strains are much more likely to cause inflammation and spur the abnormal cell division and growth of cells that lead to cancer.

H. pylori injects CagA into the epithelial cells that line the stomach. Within the cells, CagA is able to hijack various signaling pathways and disrupt proper cellular functions.

Other studies have identified RUNX3 (pronounced RUNKS-three) as an important gastric cancer tumor suppressor.........

Posted by: Janet      Read more         Source


July 21, 2010, 6:08 AM CT

Protection against ticks that carry Lyme disease

Protection against ticks that carry Lyme disease
The life cycle of the Ixodes scapularis commonly known as the deer tick or the black-legged tick. Lyme disease is caused by the spirochete Borrelia burgdorferi which is transmitted by an infected vector tick to a host during feeding.

Credit: University of Illinois

Research on the population of black-legged ticks, which can transmit Lyme disease from host animals to humans, reinforces that it is important to take preventative measures when spending time outdoors.

University of Illinois graduate student Jennifer Rydzewski conducted a four-year survey of black-legged ticks (also known as deer ticks), their host animals, and their habitat preferences in Cook, Lake, DuPage, and Piatt Counties. The survey confirmed the presence of ticks in all four counties and ticks carrying Lyme disease in Piatt County. Higher numbers of ticks were found along the Des Plaines River corridor.

"Their small size makes ticks really difficult to see. They're about the size of a poppy seed," Rydzewski said.

"Ticks in the nymph stage of their life cycle are responsible for the most human cases of Lyme disease because their peak seasonal activity coincides with increased human activity outdoors during the warmer summer months, so it's important for people to take extra precautions."

In humans, early symptoms of Lyme disease are often nondescript, flu-like symptoms such as fever, headache, and fatigue, making it difficult to diagnose from symptoms alone. In about 70 percent of the cases, people will develop the typical bullseye-shaped rash linked to Lyme disease. If it's caught in the early stages it can be treated with broad-spectrum antibiotics; however, if it's not treated early, the result can be long-term severe joint pain, arthritis and neurological damage. The disease is named after the town of Lyme, Connecticut, where many cases were identified in 1975.........

Posted by: Mark      Read more         Source


July 9, 2010, 7:00 AM CT

Vitamin B3 to treat fungal infections

Vitamin B3 to treat fungal infections
A team of scientists from the Institute for Research in Immunology and Cancer of the University of Montreal have identified vitamin B3 as a potential antifungal treatment.

Credit: Institute for Research in Immunology and Cancer (IRIC) of the University of Montreal

A team of researchers from the Institute for Research in Immunology and Cancer (IRIC) of the University of Montreal have identified vitamin B3 as a potential antifungal therapy. Led by IRIC Principal Investigators Martine Raymond, Alain Verreault and Pierre Thibault, in collaboration with Alaka Mullick, from the Biotechnology Research Institute of the National Research Council Canada, the study is the subject of a recent article in Nature Medicine

Infections by the yeast Candida albicans represent a significant public health problem and a common complication in immunodeficient individuals such as AIDS patients, cancer patients undergoing chemotherapy and recipients of organ transplants. While some therapys are available, their efficacy can be compromised by the emergence of drug-resistant strains.

The current study shows that a C. albicans enzyme, known as Hst3, is essential to the growth and survival of the yeast. Scientists observed that genetic or pharmacological inhibition of Hst3 with nicotinamide, a form of vitamin B3, strongly reduced C. albicans virulence in a mouse model. Both normal and drug-resistant strains of C. albicans were susceptible to nicotinamide. In addition, nicotinamide prevented the growth of other pathogenic Candida species and Aspergillus fumigatus (another human pathogen), thus demonstrating the broad antifungal properties of nicotinamide.........

Posted by: Mark      Read more         Source


June 28, 2010, 7:38 AM CT

MMRV vaccine associated with 2-fold risk of seizures

MMRV vaccine associated with 2-fold risk of seizures
The combination vaccine for measles, mumps, rubella and chickenpox (MMRV) is linked to double the risk of febrile seizures for 1- to 2-year-old children compared with same-day administration of the separate vaccine for MMR (measles, mumps, rubella) and the varicella (V) vaccine for chicken pox, as per a Kaiser Permanente Division of Research study appearing online in the journal Pediatrics A febrile seizure is a brief, fever-related convulsion but it does not lead to epilepsy or seizure disorders, scientists explained.

Funded by the U.S. Centers for Disease Control, the study analyzed 459,000 children 12 to 23 months old from numerous health systems across the United States receiving their first dose of measles-containing vaccine and found MMRV to be linked to a two hundred percent increased risk of fever and febrile seizures 7-10 days after vaccination compared with same-day administration of a separate shot for MMR and the varicella (chickenpox) vaccine. This study observed that the risk for a febrile seizure after the first dose of MMRV vaccine is low, eventhough it is higher than after MMR vaccine and varicella vaccine administered as separate injections.

The study found no evidence of an increased febrile seizure risk after any measles vaccine beyond 7-10 days post vaccination.........

Posted by: Mark      Read more         Source


June 8, 2010, 6:46 AM CT

Updated HIV therapy guidelines

Updated HIV therapy guidelines
Scientists from the BC Centre for Excellence in HIV/AIDS (BC-CfE) and the University of British Columbia today released a comprehensive study revealing that the 2008 IAS-USA treatment guidelines for commencing HIV therapy would create significant benefits for individuals infected with HIV and society as a whole.

The peer-evaluated mathematical modeling study, reported in the research journal PLoS ONE, shows that full implementation of HIV therapy guidelines updated in 2008 by the International AIDS Society (IAS) would lead to more people entering therapy in British Columbia (B.C.). In addition, the study shows an increase in lives saved, billions of dollars in costs averted, and a significant decrease in HIV infections.

"The study results are critically important because they reinforce the significant individual and societal benefits of starting earlier HIV therapy and provide further momentum for therapy as prevention, which in the absence of a vaccine or cure remains the best way to contain and halt the spread of HIV," said Dr. Julio Montaner, Director, BC Centre for Excellence in HIV/AIDS; President, IAS; and the Chair in AIDS Research and Head of Division of AIDS in the Faculty of Medicine at the University of British Columbia.

When the study was conducted, 4,379 people were on highly active antiretroviral treatment (HAART) in B.C. under 2006 guidelines, and an additional 6,781 individuals qualified for therapy based on the 2008 guidelines. Approximately 12,300 people were infected with HIV in B.C. at the end of 2005, with 25 per cent to 30 per cent of HIV-infected individuals unaware of their HIV status. The BC-CfE estimated the impact of HAART expansion in B.C. based on 2008 guidelines for different expansion scenarios, and focused on the 50 per cent and 75 per cent coverage of those medically eligible to receive HAART therapy. All scenarios were in comparison to the therapy coverage in B.C. under the 2006 IAS guidelines.........

Posted by: Mark      Read more         Source


May 15, 2010, 8:43 PM CT

Belly fat or hip fat

Belly fat or hip fat
The age-old question of why men store fat in their bellies and women store it in their hips may have finally been answered: Genetically speaking, the fat tissue is almost completely different.

"We observed that out of about 40,000 mouse genes, only 138 are usually found in both male and female fat cells," said Dr. Deborah Clegg, assistant professor of internal medicine at UT Southwestern Medical Center and senior author of the study appearing in the International Journal of Obesity "This was completely unexpected. We expected the exact opposite that 138 would be different and the rest would be the same between the sexes".

The study involved mice, which distribute their fat in a sexually dimorphic pattern similar to humans.

"Given the difference in gene expression profiles, a female fat tissue won't behave anything like a male fat tissue and vice versa," Dr. Clegg said. "The notion that fat cells between males and females are alike is inconsistent with our findings".

In humans, men are more likely to carry extra weight around their guts while pre-menopausal women store it in their butts, thighs and hips. The bad news for men is that belly, or visceral, fat has been linked to numerous obesity-related diseases including diabetes and heart disease. Women, conversely, are generally protected from these obesity-related disorders until menopause, when their ovarian hormone levels drop and fat storage tends to shift from their rear ends to their waists.........

Posted by: Mark      Read more         Source


May 9, 2010, 7:07 AM CT

New insights into the mystery of natural HIV immunity

New insights into the mystery of natural HIV immunity
Graphic: Christine Daniloff
When people become infected by HIV, it’s usually only a matter of time, barring drug intervention, until they develop full-blown AIDS. However, a small number of people exposed to the virus progress very slowly to AIDS — and some never develop the disease at all.

In the late 1990s, researchers showed that a very high percentage of those naturally HIV-immune people, who represent about one in 200 infected individuals, carry a gene called HLA B57. Now a team of researchers from the Ragon Institute of Massachusetts General Hospital, MIT and Harvard has revealed a new effect that contributes to this gene’s ability to confer immunity.

The research team, led by MIT Professor Arup Chakraborty and Harvard Professor Bruce Walker of MGH, found that the HLA B57 gene causes the body to make more potent killer T cells — white blood cells that help defend the body from infectious invaders. Patients with the gene have a larger number of T cells that bind strongly to more pieces of HIV protein than people who do not have the gene. This makes the T cells more likely to recognize cells that express HIV proteins, including mutated versions that arise during infection. This effect contributes to superior control of HIV infection (and any other virus that evolves rapidly), but it also makes those people more susceptible to autoimmune diseases, in which T cells attack the body’s own cells.........

Read more         Source: Massachusetts Institute of Technology


April 29, 2010, 6:25 AM CT

Antibiotic for reactive arthritis

Antibiotic for reactive arthritis
Scientists from University of South Florida College of Medicine found a combination of antibiotics to be an effective therapy for Chlamydia-induced reactive arthritis, a major step forward in the management, and possibly cure, of this disease. Results of this study are reported in the recent issue of Arthritis & Rheumatism, a journal of the American College of Rheumatology.

Reactive arthritis (ReA), also known as Reiter's syndrome, occurs in response to an infection. As per National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the bacterium most often linked to ReA is Chlamydia trachomatis. Respiratory infections with Chlamydia pneumoniae can also trigger ReA, while associated infections in the digestive tract include Salmonella, Shigella, Yersinia, and Campylobacter. ReA symptoms commonly last 3 to 12 months, eventhough symptoms can return or develop into a long-term disease. In the past it was thought that only a small percentage of people would experience chronic symptoms of ReA. However, more recent data suggests that as a number of as 30%-50% of patients could develop a chronic form of the disease. In chronic ReA, symptoms can be severe and difficult to control with therapy, which could lead to joint damage.

The use of long-term antibiotic therapy for patients with ReA is controversial. Several reported studies have indicated that prolonged antimicrobial monotherapy is not efficacious, while other studies suggest there might be a benefit, specifically with early-stage Chlamydia-induced ReA.........

Posted by: Mark      Read more         Source


March 12, 2010, 7:23 AM CT

Preventing gastric cancer with antibiotics

Preventing gastric cancer with antibiotics
H Pylori
Helicobacter pylori, a bacterium found in about 50% of humans worldwide, can cause stomach ulcers and, in extreme cases, gastric cancer. In an article for F1000 Medicine Reports, Seiji Shiota and Yoshio Yamaoka discuss the possible eradication of H. pylori infections.

Infection by the H. pylori bacterium can approach 100% in developing countries. Most infected people do not have symptoms, but a number of develop problems including stomach ulcers. H. pylori causes more than 90% of all duodenal ulcers and can also contribute to the development of gastric cancer, which is one of the world's biggest medical problems.

Shiota and Yamaoka, from Oita University, Japan, and Baylor College of Medicine, Texas, respectively, report on a large multicenter trial in Japan. Patients with early gastric cancer were randomly treated with H. pylori antibiotics after surgical resection and were followed up for three years. Patients who received antibiotic therapy had a significantly lower risk of developing gastric cancer, confirming the importance of careful management of H. pylori

However, certain populations (e.g. India and Thailand) have a high prevalence of H. pylori infection but a low occurence rate of gastric cancer. It is thought that certain strains of H. pylori (particularly east-Asian cytotoxin-associated gene [cagA]-positive strains) might carry an increased risk of developing gastric cancer, but currently identified cagA genotypes in the Asia-Pacific are not linked to cancer.........

Posted by: Janet      Read more         Source



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Did you know?
Scientists at Baylor College of Medicine in Houston have found a genetic marker that may identify individuals at greater risk for life-threatening infection from the West Nile virus. Results of the study are reported in the Nov. 15 print edition of Journal of Infectious Diseases.

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