Swine flu: What you need to know

By Debora MacKenzie from NewScientist.

Hundreds people in Mexico and an increasing number in other countries have come down with a new kind of swine flu. People are concerned because some of those infected in Mexico have died, and because this is the kind of virus that could become a serious worldwide epidemic (see Deadly new flu virus in US and Mexico may go pandemic and Threat level for flu pandemic raised).

Should I worry about this flu?

That depends on two things: how severe this flu is, and how far it spreads. Its severity is still unknown. Those who died in Mexico were young
adults who don't often die of flu, so we know this virus can be serious. But it isn't always this bad: the cases picked up in the US were mild. Outbreak investigators are now trying to find out how many people have had the virus, and how many of those were seriously ill, to get an idea of how bad it is.

Will it spread to where I live?

That depends, again, on two different things: whether the virus is transported to your region, and how efficiently it spreads between people.

So many people travel globally now that, as long as this virus keeps infecting people, it is unlikely not to get to where you live. Some countries are already using infrared cameras to spot people with fevers on flights from affected areas. But that won't stop it entirely, since five days can pass before an infected person shows symptoms, and the virus can spread before symptoms start.

The big question is how efficiently it spreads once it lands. From the number of cases in Mexico and the fact that those infected in the US had not been in contact with pigs or each other, we know that it can spread from human to human, and has done so for weeks at least. Investigators are conducting tests to see whether people who contacted known cases have also been infected to try to assess how easily it spreads. Preliminary observations in the US suggest it has spread readily to contacts of known cases.

Similar swine flu viruses have jumped from pigs to people before and have always petered out without causing a pandemic because they were not good enough at spreading in people. This virus may do the same thing.

Does this virus mean I shouldn't eat pork?

No. This virus is named swine flu because one of its surface proteins is most similar to viruses that usually infect pigs, and the whole thing is of a type that has been spreading in North American pigs for years. But this particular virus is spreading in people and we don't yet know if it infects pigs. In any case, cooking kills the virus. Wash your hands after handling meat.

(for full story please visit www.newscientist.com.)

Night vision inverts chromatin

by Elie Dolgin from TheScientist.com


Image: striatic and Animal Photos!

Researchers have discovered a cellular mechanism that helps nocturnal mammals see in the dark. Mice, cats, deer, lemurs, and other mammals that are active at night remodel the DNA within their eyes to turn photoreceptor cells into light-collecting lenses, according to a study published today (Apr. 16) in Cell.

In nearly all eukaryotic nuclei, chromatin -- the structural building block of chromosomes -- is spatially separated into distinct compartments. Condensed, non-coding heterochromatin is usually localized to the periphery of the nucleus, while extended, active euchromatin typically resides in the nuclear interior. This "conventional" pattern is nearly universal, and probably helps cells regulate essential nuclear functions such as how and when genes are expressed.

But some nuclei are special. In 2006, a team led by Didier Devys, a molecular biologist at the Institute of Genetics and Molecular and Cellular Biology in Illkirch, France, showed that mouse rod photoreceptor cells have a different arrangement in which the chromatin is "inverted." In these cells, but not in other mouse cell types, heterochromatin is shunted to the interior, where it is enveloped by a thin ring of euchromatin. With this layout, all transcription takes place at the nuclear margins rather than at the core of nucleus as per usual.

(Please visit TheScientist.com for the full story...)