2013年11月24日星期日

Stuck on flu

Stuck on flu

The findings, published online in Virology Journal by principal investigator Pascal Gagneux, PhD, associate professor in the Department of Cellular and Molecular Medicine, and colleagues, could point the way to new drugs or therapies that more effectively inhibit viral activity, and perhaps prevent some flu infections altogether.

Scientists have long known that common strains of influenza specifically seek and exploit sialic acids, a class of signaling sugar molecules that cover the surfaces of all animal cells. The ubiquitous H1N1 and H3N2 flu strains, for example, use the protein hemagglutinin (H) to bind to matching sialic acid receptors on the surface of a cell before penetrating it, and then use the enzyme neuraminidase (N) to cleave or split these sialic acids when viral particles are ready to exit and spread the infection.

Mucous membrane cells, such as those that line the internal airways of the lungs, nose and throat, defend themselves against such pathogens by secreting a mucus rich in sialic acids -- a gooey trap intended to bog down viral particles before they can infect vulnerable cells.

"The sialic acids in the secreted mucus act like a sticky spider's web, drawing viruses in and holding them by their hemagglutinin proteins," said Gagneux.

Using a novel technique that presented viral particles with magnetic beads coated with different forms of mucin (the glycoproteins that comprise mucus) and varying known amounts of sialic acids, Gagneux and colleagues demonstrated that flu viruses counteract the natural barrier by also using neuraminidase to cut themselves free from binding mucosal sialic acids.

More notably, he said that by blocking neuraminidase activity in the mucus, the viruses remain stuck. "They can't release themselves from the mucus decoy and thus can't infect."

The discovery is likely to alter the way researchers and pharmaceutical companies think about how viruses and flu therapies function. Existing drugs like Tamiflu and Relenza inhibit neuraminidase activity and presumably dampen the ability of the flu virus to spread among cells. The work by Gagneux and colleagues suggests inhibiting neuraminidase activity in mucus may reduce the initial risk of infection.

The challenge will be to restrict neuraminidase inhibition to the mucus. Many types of cells in the human body produce neuraminidases, each performing vital cellular functions, particularly in the brain. Limiting neuraminidase inhibition to relevant mucus-secreting cells is necessary to reducing potential side effects.

"The airway's mucus layer is constantly being shed and renewed, within a couple of hours the entire layer is replaced by a new layer," said first author Miriam Cohen, PhD, an assistant project scientist in Gagneux's lab. "A drug or compound that slows down neuraminidase activity rather than completely inhibit its activity will suffice to enhance the natural protective effect of mucus and prevent infection."


Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.


SANYO IC NS IC Switching Diodes INFLNEON Diodes Civil IC NXP Transistors IR Diodes IC(Integrated Circuits) Infineon Technologies Transistors PANASONIC FAIRCHILD diodes Metal Can Packages Transistors Cypress IC ST Diodes Freescale Semiconductor TOSHIBA Transistors Switches YAGEO Resistors NXP Diodes Kingbrigt LED Rectifier Diodes BB IC ELPIDA IC NEC Transistors TI IC Electronic News Industrial IC Multi-units Transistors MOTOROLA IC ON Transistors Other Parts MURATA IC Current Sensors Resistors ON Diodes MAXIM IC Fairchild Semiconductor Transistors About US LITTELFUSE Diodes Chip Fuses Resistor Arrays
http://www.suvsystem.com/a/7317.aspx