FEN

Female sex hormones play a vital role in defense against sexually transmitted diseases

Two McMaster University studies, to be published in the Journal of Virology, show that sex hormones have a profound effect on susceptibility of female mice to the herpes simplex virus, type 2 (HSV-2 ), one of the most common sexually transmitted diseases. Charu Kaushic, assistant professor and supervisor of the studies, says the implication of this work is quite significant. "The research...

In the sea slug's defense against lobsters, confusion is key

Like many other marine creatures, Aplysia, a common sea slug, enlists chemical defenses against its predators, but the mechanisms by which such chemical attacks actually work against their intended targets are not well understood by researchers. New work has now shown that such chemical defenses can involve modes of trickery that had not previously been appreciated as components of chemical defen...

Defensins neutralize anthrax toxin

Researchers at the University of Pennsylvania School of Medicine have identified a link between a critical cancer pathway and an Epstein-Barr Virus (EBV) protein known to be expressed in a number of EBV-associated cancers. Their findings demonstrate a new mechanism by which EBV transforms human B cells from the immune system into cancerous cells, which can lead to development of B-cell lymphomas....

Disease diagnosis, biodefense among UH chemical research projects

With 33 presentations of original research that showcase applications ranging from early-stage disease diagnosis to fuel cells and batteries, the University of Houston will be well represented at the 229th National Meeting of the American Chemical Society (ACS), March 13 to 17 in San Diego. Founded in 1876, the ACS is a nonprofit, scientific and educational organization and the largest sci...

Defenseless plants arm themselves with metals

A group of plants that uses metal to defend against infection may do so because the normal defense mechanism used by most other plants is blocked. Purdue University researchers found that this group of plants produces, but does not respond to, the molecule that triggers the infection response used by nearly all other plants. The molecule does, however, allow this group of plants, called m...

Defensins Ward Off HIV In Two Ways

The body attempts to protect itself from HIV infection via the innate immune system. Defensins are proteins found in cells, which have been shown to have anti-HIV activity. However, the mechanism by which the defensins control HIV infection has not been known. Appearing online on February 17 in advance of publication in the March 1 print edition of the Journal of Clinical Investigation, Theresa C...

Comprehensive biodefense text published

A new book, Biological Weapons Defense: Infectious Disease and Counterbioterrorism, deals with the intentional causality of disease. Published by Humana Press, this text is also available in e-Book. Many of the contributors come from the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), the nation's premier biodefense laboratory. In this 624-page, hardcover text edite...

How A Latent Virus Eludes Immune Defenses

For a virus to survive, it must elude the ever vigilant immune sentinels of its host. A latent virus can escape immune detection if it resides in nondividing cells and doesn’t produce any proteins. No viral proteins means no red flags for immune cells. If the virus targets one of the many cell types that rarely divide, it’s relatively safe while latent. But some viruses, like the gamma-herpesviru...

Ancient immune defense mechanism is no match for HIV-1

Researchers have discovered that mammalian cells infected with HIV-1 engage a primitive defense mechanism that was previously observed only in plants and invertebrates. The research also reveals exactly how HIV-1 successfully thwarts this rare form of immunity in vertebrate cells. However, elucidation of the mechanism HIV-1 uses to protect itself provides some critical insight into a potential vu...

Tamoxifen-like drug suggests new ways to selectively block estrogen

The ability of an experimental drug known as GW5638 to change the shape of the estrogen receptor is helping researchers understand why drugs like tamoxifen and raloxifene behave the way they do, simulating the effects of estrogen in some tissues and blocking it in others. The finding indicates that this little-known drug may play an important role in preventing, as well as treating, breast cancer...

Discovery could be key to bioterrorism defense

A collaborative research team from the Uniformed Services University of the Health Sciences (USU), the Australian Animal Health Laboratory (AAHL) and the National Cancer Institute (NCI) have made a major breakthrough in efforts to combat two deadly viruses that could be engineered for use as bioweapons. The team isolated the functional receptor for the Nipah and Hendra viruses--naturally occurrin...

Variation in HIV's ability to disable host defenses contributes to rapid evolution

One of the reasons HIV is so difficult to contain and treat is its rapid evolution. Understanding how host defenses and viral countermeasures contribute to that evolution is vital. Vif is full o...

Plants have a double line of defence

Max Planck researchers in Cologne, Germany demonstrate that a multi-step defence system underlies the durable resistance of plants to fungal parasitesPlants are exposed to many different pathogens in the environment. Only a few of these pathogens, however, are able to attack a species of plant and "make it sick". If a particular pathogen is unable to attack a plant, that means that the plant is r...

Scientists show that tick-borne flaviviruses use a novel mechanism to evade host defenses

Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, have made the surprising discovery that flaviviruses, which cause such serious diseases as West Nile fever, yellow fever and forms of encephalitis, evade immune system defenses in different ways depending on whether they are transmitted by mosquitoes or ticks. This findin...

Researchers uncover E. coli's defense mechanism

Iron key to nitric oxide reductionResearchers at the Georgia Institute of Technology and the John Innes Centre in the United Kingdom have uncovered a mechanism with which disease-causing bacteria may thwart the body's natural defense responses. The findings, which could ultimately lead to the development of more effective antibiotics, appear in the September 29, 2005 issue of the journal Nature.<...

New Lab Research May Help Those Deafened By Immune System Attack

Our immune system protects us from disease, destroying invading microbes with a swarm of attacking cells. But it can also go haywire for no apparent reason, ganging up on normal tissues in our body and wreaking havoc. In thousands of people each year, the immune system attacks the inner ear, home to the tiny, delicate structures that allow us to hear. Without warning, in days or weeks, pat...

Ibruprofen and other commonly used painkillers for treating inflammation may increase the risk of heart attack

When it comes to the deadly skin cancer melanoma, studying functional tissue rather than cell lines may better provide insight into the disease's development, according to new research from a Howard Hughes Medical Institute predoctoral fellow at Stanford University School of Medicine. Though multiple genetic alterations are associated with melanoma development, scientists have not been abl...

Energy management in cells may hold key to cancer defense

In an ongoing effort to fight disease by manipulating energy regulation of cells, a collaborative study led by Dartmouth Medical School (DMS) has demonstrated that cells lacking a tumor-suppressing kinase called LKB1 can still maintain healthy energy levels when they become stressed. This energy regulation is essential for keeping cells from dying off too quickly. The study's results could sign...

Bacteria recognize antimicrobials, respond with counter-defenses

Many living things, from fruit flies to people, naturally produce disease-fighting chemicals, called antimicrobial peptides, to kill harmful bacteria. In a counter move, some disease-causing bacteria have evolved antimicrobial detectors. The bacteria sense the presence of antimicrobial peptides as a warning signal. This alarm sets off a reaction inside the bacteria to avoid destruction. Un...

The very defensive caterpillar

Caterpillars are bleeding defensive! Insects are known to lack an antibody-mediated immune response, and research in caterpillars has recently shown that, instead, they produce protective proteins in response to bacterial infection. The pattern recognition receptors (PRR) and antibacterial effectors produced at a first infection still function to protect against a repeated challenge. These result...

Researchers discover new tumor defense system

Researchers have discovered that tumors release fatty acids that interfere with the cells that are trying to kill them. Consequently, strategies that reduce the amount of fatty acids surrounding the tumors may give a boost to anti-cancer therapeutics. The details of these findings appear in the September issue of the Journal of Lipid Research, an American Society for Biochemistry and Molecular Bi...

Study: Plants use dual defense system to fight pathogens

Researchers have uncovered the link between two biochemical pathways that plants use to defend themselves against pathogens ?pathways that scientists have long believed worked independently of each other. Knowing how these pathways of immunity work may one day help researchers breed plants that can better resist a variety of pathogens, said David Mackey, the study's lead author and an ass...

New NIAID grants strengthen national biodefense and emerging infectious diseases research network

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, today announced four-year grants totaling approximately $80 million for two new Regional Centers of Excellence for Biodefense and Emerging Infectious Diseases Research (RCE). The grants to the University of California, Irvine, and Colorado State University (Fort Collins) mark the completi...

Study provides insight into cellular defenses against genetic mutation

Nature's finesse revealed in quality surveillance systemWith their latest discovery, researchers have significantly advanced the understanding of how human cells protect themselves from constant and potentially destructive changes in gene expression. According to an article published in this month's Nature Structural & Molecular Biology, the research is important because the protection itself...

Bacterial protein mimics host to cripple defenses

Like a wolf in sheep's clothing, a protein from a disease-causing bacterium slips into plant cells and imitates a key host protein in order to cripple the plant's defenses. This discovery, reported in this week's Science Express by researchers at the Boyce Thompson Institute (BTI) for Plant Research, advances the understanding of a disease mechanism common to plants, animals, and people. T...

Genetic defenders protect crops from fungal disease

Like waves of soldiers guarding a castle gate, multiple genetic defenders cooperate to protect plant cells against powdery mildew disease, according to a new study. Powdery mildew is a common fungal infection in plants that attacks more than 9,000 species, including many crops such as barley and wheat, and horticultural plants such as roses and cucumbers. The researchers, including Shauna Somervi...

Plant defenses prompt bacterial countermeasure in the form of 'island' DNA excision

Seeking to catch an arms-race maneuver in action, researchers have uncovered new evidence to explain how bacteria in the process of infecting a plant can shift molecular gears by excising specific genes from its genome to overcome the host plant's specific defenses. Throughout evolution ?in the wild and in crops cultivated by humans ?plants have developed systems for resisting the attack o...

Gene variation affects tamoxifen's benefit for breast cancer

One of the most commonly prescribed drugs for breast cancer, tamoxifen, may not be as effective for women who inherit a common genetic variation, according to researchers at the University of Michigan and the Mayo Clinic. The genetic variation affects the level of a crucial enzyme that activates tamoxifen to fight breast cancer. The study, co-led by researcher James Rae, Ph.D., at the Univ...

Sea slug mixes chemical defense before firing at predators

When threatened by predators, sea slugs defend themselves by ejecting a potent inky secretion into the water consisting of hydrogen peroxide, ammonia and several types of acids. A team of researchers with the Atlanta-based Center for Behavioral Neuroscience (CBN) has found that this secretion is produced from normally inert chemicals stored separately in two glands. The discovery, published in th...

Study shows that cells have a natural defense against HIV

Scientists here have discovered a previously unknown mechanism that cells use to fight off the human immunodeficiency virus (HIV), the cause of AIDS. The study was led by...

A clue from macaques yields evidence for impaired retroviral defense genes in humans

Researchers Harmit Malik and Michael Emerman and colleagues at the Fred Hutchinson Cancer Research Center have found that a surprisingly large fraction of humans may be impaired in the function of a recently discovered arm of the body's defense against invading retroviruses such as HIV. One of the key components of this "intrinsic immunity" is encoded by the TRIM5 gene. This gene was disc...

Molecular force field helps cancer cells defend against attack

Much as the famed starship Enterprise would deploy a deflector shield to evade enemy attack, tumor cells are capable of switching on a molecular force field of their own to fend off treatments aimed at killing them. Now University of Florida researchers have found a chink in their armor. The cells churn out an enzyme that bonds with a protein, creating a protective barrier that deflects da...

Oxidation defense in mosquitoes benefits malaria parasite

Scientists from two universities in Italy and Virginia Tech in the United States have determined the structure of a protein that is responsible for the production xanthurenic acid (XA) in Anopheles gambiae, the malaria carrying mosquitoes. XA plays a key role in the sexual reproduction of the malaria parasite (Plasmodium falciparum) in A. gambiae mosquitoes. Interfering with the formation of XA c...

Tamoxifen for breast cancer prevention does not benefit most women

Most women at high risk for breast cancer do not increase their life expectancy by taking the drug tamoxifen, according to a new analysis by researchers from UC Davis, UCSF, the University of Pittsburgh and McMaster University in Ontario, Canada. In addition, the researchers showed that tamoxifen is an extraordinarily expensive cancer-prevention strategy, costing as much as $1.3 million per year...

Mussels evolve quickly to defend against invasive crabs

Scientists at the University of New Hampshire (UNH) have found that invasive crab species may precipitate evolutionary change in blue mussels in as little as 15 years. The study, by UNH graduate student Aaren Freeman with associate professor of zoology James Byers and published in the Aug. 11 issue of the journal Science, indicates that such a response can evolve in an evolutionary nanosecond com...

Defense peptide found in primates may block some human HIV transmissions

As primates evolved 7 million years ago, the more advanced species stopped making a protein that University of Central Florida researchers believe can effectively block the HIV-1 virus from entering and infecting blood cells. HIV-1 often mutates quickly to overcome antiviral compounds designed to prevent infections. But a research team led by Associate Professor Alexander Cole of UCF's Bu...

Pak1 expression increases tamoxifen resistance in breast cancer patients

A protein that activates estrogen receptors in breast cancer may play a role in resistance to therapeutic effects of anti-estrogen tamoxifen treatment, according to a study in the May 17 Pak 1 is a member of a family of proteins involved in many cell functions, such as gene expression, cell movement, and cell death. Previous studies have...

DNA to the defense

A team of scientists headed by Dr. Sara Melville at the University of Cambridge has shown that the parasite known to cause African sleeping sickness has evolved an unusual chromosomal structure as a result of environmental adaptation. In this parasite, the chromosomes are highly enriched in subtelomeric sequences ?dynamic and variable regions that connect the chromosome ends to the gene-rich cor...

Molecular 'on/off switch' controls immune defenses against viruses

Much like flipping a light switch, the hepatitis C virus turns on human immune defenses upon entering the body but also turns off those defenses by manipulating interaction of key cellular proteins, UT Southwestern Medical Center researchers have found. This same molecular "on/off switch" controls immunity against many viruses, highlighting a potential new target for novel therapeutics t...

Restoring tamoxifen sensitivity in resistant breast cancer cells

The widely used breast cancer drug tamoxifen (Nolvadex®), which can become less effective over time, might retain its full strength indefinitely if used along with a second drug, according to new research in mice conducted by investigators from the National Cancer Institute (NCI), part of the National Institutes of Health, and their partners. The results appear in the December 11, 2006, issue of...