How Plants and Bacteria 'Talk' to Thwart Disease

When it comes to plants' innate immunity, like many of the dances of life, it takes two to tango. A receptor molecule in the plant pairs up with a specific molecule on the invading bacteria and, presto, the immune system swings into action to defend against the invasion of the disease-causing microbe.

Unwrapping some of the mystery from how plants and bacteria communicate in this dance of immunity, scientists at the University of California, Davis, have identified the bacterial signaling molecule that matches up with a specific receptor in rice plants to ward off a devastating disease known as bacterial blight of rice. The researchers, led by UC Davis plant pathologist Pamela Ronald, will publish their findings in the Nov. 6 issue of the journal Science.

"The new discovery of this bacterial signaling molecule helps us better understand how the innate immune system operates," Ronald said."Because similar pairs of receptors and bacterial signaling molecules are known to exist not only in rice but also in other plants, as well as animals and humans, we are hopeful that this work will lead to new strategies for controlling diseases in plants and people," she said.

Disease resistance background

In 1995, Ronald's laboratory identified the XA21 gene, which produces a receptor protein that recognizes Xanthomonas oryzae pv. Oryzae, also known as Xoo, which causes bacterial blight disease. Xoo and other species of Xanthomonas infect virtually every crop species in the world.

Subsequent discoveries revealed that receptors with striking structural similarities to the XA21 receptor protein exist in other plants, flies, mice and even humans. These receptors were later named pattern recognition receptors or PRRs because they have the ability to recognize molecules that occur across species in a large class of disease-causing microbes. These receptors then can launch a protective immune defense on behalf of the plant or animal.

Together, the receptors (PRRs) and the microbial molecules they recognize comprise a previously unknown system of immunity called innate immunity. As the name suggests, this form of immunity is built into the genetic makeup of the plant, rather than developing over time with repeated exposure to disease-causing microbes. Unlike animals, plants do not produce antibodies.

The New Findings

In their newly published study, Ronald and her colleagues identified a peptide -- a compound that they call ax21 -- as the molecule that binds with the XA21 receptor protein. The binding triggers a defense response against the bacterial disease.

The researchers note that ax21 is also found in many other species of Xanthomonas as well as in Xylella fastidiosa, a microbe that causes the devastating Pierce's disease in grapes. Furthermore, ax21 is even found in Stenotrophomonas maltophilia, a bacterium that causes respiratory tract infections in humans.

"These studies have led to a convergence in our understanding of the molecular mechanisms that govern how disease-causing microbes interact with the plants and animals they infect," Ronald said.

"We are hopeful that these discoveries will benefit agriculture and medicine in the United States and around the world by leading to development of treatments that will disrupt bacterial infection," she said.

Source: Sciencdaily

How To Kill Bacteria on Your Tooth Brush

Your toothbrush can be a breeding ground for bacteria. If you leave your toothbrush near someone else, you could be spreading colds much more easily than you think. Follow these easy steps to naturally keep your toothbrush clean and bacteria free.

                            

• Fill bottom of cup with 1 tsp Hydrogen Peroxide in 1 cup (240ml) of Water. Place your toothbrush in solution and shake    it well. Hydrogen Peroxide solution is natural disinfectant and will kill bacteria on toothbrush.
• Before applying toothpaste rinse your toothbrush with water and rinse it with Hydrogen Peroxide. Hydrogen Peroxide will also acts as Whitening agent thereby giving you sparkling white teeth.

Source: MSN

The New Allergy Zones

The spring allergy season has sprung—and wrought plenty of discomfort for the approximately 35 million Americans with seasonal allergies. Pollen may not be all that's making your eyes water and nose run, though. Surprising allergens lurk in unexpected places in your home and make you feel even worse. In fact, the list of sneeze-inducing culprits is long: animal dander, mold, dust, and dust mites (tiny insects that thrive on organic matter, primarily flakes of skin), as well as pollen carried into the house from outside. But these irritants are manageable—and getting a handle on them will help reduce your symptoms. We went to four top experts for the unexpected sources of your sneezes and some room-by-room tips for eliminating them.

Living room: Surprise allergy source: Pet-owning visitors

Friends with pets usually have animal dander on their clothes. When they visit, they can deposit this irritant on upholstered furniture—even if they don't bring Fido or Felix with them.

Solution: Vacuum your couches and padded chairs after pet-owning pals sit on them. Prevent the allergens from spewing right back out of the machine by using one with a HEPA filter (which traps tiny particles so they can't escape the dust bag).

Surprise allergy source: Couch pillows, throws, and stuffed toys

These items come into contact with skin, and that means tiny flakes that slough off and encourage dust mites. If your pet sits on, fetches, or plays with any of these, they're also covered with animal dander.

Solution: Tumble the items in the dryer on high for 10 to 15 minutes each week. (If this will damage the material, clean instead according to the manufacturer's instructions.)

Bedroom Surprise allergy source: Shelves

It's not just your novel's plot twists that are causing your eyes to tear up and your nose to run. You can also blame the dust that collects on books and other shelf-dwellers, including framed photographs and mementos. Books can also contribute to indoor mold problems, especially in humid conditions.

Solution: Keep shelves of all kinds, including bookshelves, away from the bed, or banish them from the bedroom entirely. Place trinkets behind glass doors so they don't collect dust. Clean surfaces and vacuum bedroom floors at least once a week.

Surprise allergy source: Bed pillows

The warmth and humidity of your body encourage dust mites to grow in bed pillows, no matter what type of stuffing they have.

Solution: Either trade old pillows for new ones annually, or encase pillows in allergy-proof covers that you wash once or twice a month in hot water (follow the manufacturer's instructions). The most allergy-resistant, comfortable cases are made of tightly woven fabric that's impermeable to dust mites—and feels good to the touch.

Bathroom Surprise allergy source: The floor mat

Trapped moisture in the bath mat causes dust mites and mold to thrive.

Solution: Choose a washable mat and clean it weekly. After a shower or steamy bath, hang it up and open a window or run the fan.

Kitchen Surprise allergy source: The refrigerator door seal

As you transfer food in and out of the refrigerator, moisture, crumbs, and spills can build up in the crevices of the door seal and encourage mold to flourish there.

Solution: Wipe the seal with a mixture of mold-zapping bleach and water weekly; use a cotton swab to get into the grooves and clean them thoroughly.

Surprise allergy source: Cooking steam

Steam wafts from pots and pans as you cook and settles in places you may not clean daily, causing mold to build up. Spots where dampness may land include walls, ceilings, cupboard doors, upper shelves, and areas hidden behind large appliances.

Solution: Run the stove's exhaust fan to vent cooking moisture—not just smells—out of the house. If mold does appear, eliminate it with a solution of bleach and water.

Laundry room Surprise allergy source: Damp clothes

Mold and bacteria can develop on damp, unwashed clothing that sits around for days before it's laundered, as well as on clean items left in the washer tub for more than a few hours.

Solution: Don't let moist, dirty laundry build up, and dry freshly washed items ASAP. Here's a bonus idea: Use liquid detergent instead of powder, which can produce irritating dust, worsening your allergy symptoms.

All around the house Surprise allergy source: Your hair and clothes

When you arrive home after spending time outdoors, you carry in dust and pollen on your shoes and clothes and in your hair (long hair and loose hairstyles tend to trap more irritants than short or tightly bound strands).

Solution: When outside, cover your hair with a hat or scarf. When you get home, remove your head covering and shoes inside the door, change into clothes that you wear only indoors, and shampoo and dry your hair. Wash your comb and brush weekly to keep them free of any irritants they've picked up.

Surprise allergy source: Plants

Damp soil can support the development of mold, and if you spill occasionally as you water, you can encourage growths in any carpet or curtains you happen to hit.

Solution: Give away or toss out plants if mold and dust cause you to have severe symptoms. If you choose to keep the plants instead, place the pots on tile and well away from curtains. Bonus tip: A layer of pebbles or small stones placed on top of the soil will prevent the release of mold spores that may be growing in the soil.

Surprise allergy source: The fish tank

Mold grows on parts of the tank or bowl that are out of the water but nevertheless remain damp. Carelessly strewn fish food also helps mold develop and can nourish a dust mite colony.

Solution: Use a rag to dry off above-water tank parts daily. When you feed the fish, make sure the food lands in the water, not on the tabletop or floor.

Source:Msn