15 April 2010: Late Afternoon

This will mostly be a bunch of interesting links:

Peoria: Peoria Pundit points us to one of those “how good is your city surveys” which ranks Peoria 69 out of 200 cities in terms of “best places for business and careers”. The survey is from Forbes.com. Billy notes that these surveys are often dismissed, unless the rankings are favorable.

Science
A large fireball was seen in the sky over some midwestern cities. Follow the link to see the video and to read the article; meteor shower perhaps? Hat tip: Dude Spellings.

In the field of medicine (via 3-quarks daily): scientists are now able to transplant the genetic material in the nucleus of a fertilized human egg into another fertilized egg, without carrying over mitochondria. This is good news for those who might be prone to diseases caused my mutation of the mitochondria DNA. Source article: here (Nature).

Scientists have also made a recent advance in cancer research:

Researchers say they have discovered a new molecular player in determining whether breast cancer cells will spread through the body: long strands of RNA known as lincRNAs that turn off tumor suppressor genes. The finding may lead to a test for predicting metastasis as well as drugs for preventing it.

(via: 3-quarks daily)

Dr. Andy has also contributed a couple of interesting links, one of which is here (the other will get it’s own post):

One of these links talks about a type of bacteria found in the gut of Japanese people: it helps them digest foods like seaweed. But this bacteria is not generated from the human body itself; rather it came from what Japanese people ate and, yes, it can be passed from a mother to her infant. The whole article is interesting; here is a part of it:

Hehemann began with Zobellia, whose genome had been recently sequenced. This bacterium turned out to be the proud owner of no fewer than five porphyran-breaking enzymes. This group was entirely new to science, they are all closely related and they clearly originated in marine bacteria. Their unique ability earned them the name of ‘porphyranases’ and the genes that encode them were named PorA, PorB, PorC and so on.

They are clearly not alone. Using his quintet as a guide, Hehemann found six more genes with similar abilities. Five of them hailed from the genomes of other marine bacteria – that was hardly surprising. But the sixth source was a far bigger shock: the human gut bacterium Bacteroides plebeius. What was an oceanic gene doing in such an unlikely species? Previous studies provided a massive clue. Until then, six strains of B.plebeius had been discovered, and all of them came from the bowels of Japanese people.

Nori is, by far, the most likely source of bacteria with porphyran-digesting genes. It’s the only food that humans eat that contains any porphyrans and until recently, Japanese chefs didn’t cook nori before eating it. Any bacteria that lingered on the green fronds weren’t killed before they could mingle with gut bacteria like B.plebius. Ruth Ley, who works on microbiomes, says, “People have been saying that gut microbes can pick up genes from environmental microbes but it’s never been demonstrated as beautifully as in this paper.”

In fact, B.plebeius seems to have a habit of scrounging genes from marine bacteria. Its genome is rife with genes that are more closely related to their counterparts in marine species like Zobellia than to those in other gut microbes. All of these borrowed genes do the same thing – they break down the complex carbohydrates of marine algae.

To see whether this was a common event, Hehemann screened the gut bacteria of 13 Japanese volunteers for signs of porphyranases. These “gut metagenomes” yielded at least seven potential enzymes that fitted the bill, along with six others from another group with a similar role. On the other hand, Hehemann couldn’t find a single such gene among 18 North Americans. “We were trying at lunch to think about where you might see patterns this clean,” says Ley. “You’d have to find another group of people with a very specialised diet. Because this involved seaweed and marine bacteria, it might be one of the cleanest demonstrations you’d get.”

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