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Archive - Aug 13, 2014

Gene Linked to Huntingtin’s Disease Plays Critical Role in Normal Memory Development

It has been more than 20 years since scientists discovered that mutations in the gene huntingtin cause the devastating progressive neurological condition Huntington’s disease, which involves involuntary movements, emotional disturbance, and cognitive impairment. Surprisingly little, however, has been known about the gene’s role in normal brain activity. Now, a study from The Scripps Research Institute’s (TSRI’s) Florida campus and Columbia University shows it plays a critical role in long-term memory. “We found that huntingtin expression levels are necessary for what is known as long-term synaptic plasticity—the ability of the synapses to grow and change—which is critical to the formation of long-term memory,” said TSRI Assistant Professor Sathyanarayanan V. Puthanveettil, who led the study with Nobel laureate Dr. Eric Kandel of Columbia University. In the study, published online on July 23, 2014 by the journal PLOS ONE, the team identified an equivalent of the human huntingtin protein (image)in the marine snail Aplysia, a widely used animal model in genetic studies, and found that, just like its human counterpart, the protein in Aplysia is widely expressed in neurons throughout the central nervous system. Using cellular models, the scientists studied what is known as the sensory-to-motor neuron synapse of Aplysia—in this case, gill withdrawal, a defensive move that occurs when the animal is disturbed. The study found that the expression of messenger RNAs of huntingtin—messenger RNAs are used to produce proteins from instructions coded in genes—is increased by serotonin, a neurotransmitter released during learning in Aplysia. After knocking down production of the huntingtin protein, neurons failed to function normally.

Australia Results Indicate HPV Vaccine Causes Dramatic Reduction in Genital Warts

In the most comprehensive assessment of its type, UNSW Australia-led research has found that in just four years, the HPV vaccine has resulted in a dramatic drop in genital warts in young Australians from a range of backgrounds, a result that could herald further good news for cervical cancer rates in future. The research, which was done in collaboration with the University of Sydney, is based on national hospital admission rates and shows a similar result in the female indigenous population, which has historically had significantly higher rates of cervical cancer. Genital warts and cervical cancer are both caused by HPV. The work was published online on August 12, 2014 in the Journal of Infectious Diseases. In the four years after the national program for school-aged girls was rolled out in 2007, there was a 90% drop in genital warts for girls aged between 12 and 17, and a 73% decrease for women between 18 and 26 years. The vaccine appeared to have an indirect protective effect among young men between the ages of 18 and 26, with a 38% drop in genital warts even prior to boys being vaccinated at school. "This is a fantastic outcome," says the senior author of the paper, Associate Professor Karen Canfell, from UNSW's Lowy Cancer Research Centre. "This is a condition which can be distressing and embarrassing and most often occurs when people start to become sexually active." The vaccine used in the National HPV Vaccination Program in Australia, Gardasil, provides protection against four strains of HPV. HPV 16 and 18 are implicated in several cancers, particularly cervical cancer. Two other strains, HPV 6 and 11 are associated with 90% of genital warts.

MRSA Colonization Common in Groin and Rectal Areas

Colonization of methicillin-resistant Staphylococcus aureus (MRSA) allows people in the community to unknowingly harbor and spread this life-threatening bacteria. The inside of the front of the nose is where this bacteria is most predominant, but new research shows nearly all colonized individuals have this bacteria living in other body sites. The study was published in Infection Control and Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America. "While people colonized with MRSA may not be sick, the bacteria can become aggressive and lead to infection in the person or others," said Kyle Popovich, M.D., M.S., lead author of the study. Because of the risk of transmission, hospitals have developed infection control and prevention efforts that identify individuals with nasal MRSA colonization. These patients may be placed in isolation or decolonized of MRSA by treating and removing the bacteria from the patient's nose and skin. These strategies have been used to prevent MRSA infections for the patient and to decrease risk of spread of MRSA to other patients. Several states also mandate these MRSA surveillance programs. Researchers collected surveillance swab specimens for nose and other body sites from patients at Stroger Hospital of Cook County within 72 hours of admission from March 2011-April 2012. After analyzing the samples, researchers observed that, following the nose, the rectal and groin areas were frequent sites of colonization of community-associated MRSA. The bacteria were found in these body sites more often in men than in women. "Our findings show that MRSA colonization is not limited to the nose. This may have important implications MRSA surveillance programs nationwide," said Dr. Popovich.

How Spiders Fix Their Webs

Spider silk is light and delicate, while incredibly resilient and tear-resistant. Understanding the structure and way of construction of these threads is a challenge taken up by a research team of Kiel University. The scientists examined five different spider species regarding the adhesion and tensile strength of a particular silk they use to fix the main thread to a surface. As shown in their new study published online on July 16, 2014 in the international Journal of the Royal Society Interface, the scientists found out that the substrate has a particularly significant impact on the silk’s adhesion. The research group led by Professor Stanislav Gorb (Institute of Zoology, Kiel University) has attended to the functional analysis of animal surfaces. Why do a gecko’s feet adhere to a wall? Why does a snake’s skin not fray out while the snake is moving forward? The group’s most recent study object is spider silk: spiders use the so-called safety thread to prevent them from falling, to lower themselves and to build the web’s framework. The threads are fixed to the surface and other threads by means of so-called attachment discs generated by rotating motions of the silk glands and applied in the form of a special lattice pattern. The scientists of Dr. Gorb’s research team investigated how attachment discs adhere to various surfaces. “To this end, we placed the spiders on glass, Teflon, and the leaf of a sycamore maple, and they produced attachment discs on each surface. Subsequently, we performed tensile tests to measure the strength necessary to detach the discs from the substrate,” says the author of the current study, Jonas Wolff.

Gene That Controls Nerve Conduction Velocity Linked to Multiple Sclerosis

A new study published online on August 12, 2014 in The American Journal of Pathology identifies a novel gene that controls nerve conduction velocity. Investigators report that even minor reductions in conduction velocity may aggravate disease in multiple sclerosis (MS) patients and in mice bred for the MS-like condition experimental autoimmune encephalomyelitis (EAE). A strong tool for investigating the pathophysiology of a complex disease is the identification of underlying genetic controls. Multiple genes have been implicated as contributing to the risk of developing MS. Unlike studies that have focused on genetic regulators of inflammation, autoimmunity, demyelination, and neurodegeneration in MS, this study focused on nerve conduction velocity. Investigators found that polymorphisms of the inositol polyphosphate-4-phosphatase, type II (Inpp4b) gene affect the speed of nerve conduction in both mice with EAE and humans with MS. "Impairment of nerve conduction is a common feature in neurodegenerative and neuroinflammatory diseases such as MS. Measurement of evoked potentials (whether visual, motor, or sensory) is widely used for diagnosis and recently also as a prognostic marker for MS," says lead investigator Saleh M. Ibrahim, M.D., Ph.D., of the Department of Dermatology, Venereology, and Allergology of the University of Lubeck (Germany). Using several genomic approaches, the investigators narrowed their search to the genetic region controlling the enzyme inositol-polyphosphate-4-phosphatase II (INPP4B), the product of which helps to regulate the phosphatidyl inositol signaling pathway. Enzymes in this family are involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival, and intracellular communication.