A, T, G, C and What?!?

New nucleotide discovered in mouse brain

By Amber Sasse Posted 04.17.2009 at 4:06 pm

Turns out life has more essential building blocks to play with than previously thought: researchers at Rockefeller University have discovered a new nucleotide in the mammalian DNA code. Remember good ol' adenine, thymine, guanine and cytosine? Well, the alphabet of our DNA sequence is about to receive a new letter. Meet 5-hydroxymethylcytosine; we aren't sure what it does or where it's located, but we know it's important -- really important.

In the announcement, Nathaniel Heintz, director of the molecular biology lab that conducted the research, was exuberant about the significance of the finding: "This is another mechanism for regulation of gene expression and nuclear structure that no one has had any insight into. I think this finding will electrify the field of epigenetics."

Epigenetics, or the study of heritable traits that occur without changes in DNA sequence, pioneered the discovery of a fifth nucleotide, 5-methylcytosine (5-mC), and now it adds a sixth. Since genes alone cannot account for the stark differences among mammals -- all which share a sizeable amount of genetic material -- scientists believe the differentiation stems from a dynamic regulation of gene expression rather than the gene sequence alone. Which is why the discovery of a new nucleotide is so remarkable: it may prompt DNA demethylation, or help regulate gene expression.

Even more remarkable is that the discovery was an act of serendipity. According to Skirmantas Kriaucionis, a postdoctoral associate in the Heintz lab, "We didn't go looking for this modification. We just found it." Kriaucionis was investigating the levels of 5-methylcytosine in two different brain neurons (Purkinje cells and granule cells) and while analyzing the epigenetic makeup of these cells discovered a significant amount of an unknown nucleotide.

Kriaucionis performed several tests to determine the elemental composition of the unknown substance and all tests converged on one result: 5-hydroxymethylcytosine, a nucleotide previously found only in bacterial viruses, which he found "abundant in the mouse and human brain." The next step is to deduce the genetic location, role, and effects of the new nucleotide, believed to have a link to brain function.

Found at http://www.popsci.com/scitech/article/2009-04/t-g-c-and-what

Killer Bugs!!

6 of the Deadliest killer-insects in the world! (from http://webecoist.com)

These deadly insects are naturally designed to kill. The effects of their bites range from painful to deadly for humans, and they inject their prey with lethal salivary secretions that immobilize them and ease ingestion and digestion. These six represent some of the stranger and more interesting assassins of the insect world.

Wheel Bug (Arilus Cristatus)

(images via: mean and pinchy and nickso)

This is one of the largest terrestrial bugs in North America, growing up to about 2 inches. Noticeable on its back is what looks like a wheel or cog. These vicious predators prey on caterpillars and beetles, piercing their prey with a large beak and injecting enzyme fluids, paralyzing their prey, and slowly dissolving their victim’s insides. Being bitten by a wheel bug is excruciating, and often times the wound can take months to heel, leaving a noticeable scar.

Bee Assassin (Apiomerus crassipes)

(images via: sankax and ken-ichi)

These little killers have hairs on their legs that allow them to catch and hold onto their prey. While they certainly love to catch and eat bees, they are equally opportunistic when it comes to other prey. They ambush their victims and immobilize them with toxic venomous secretions.

Spined Assassin (Sinea Diadema)

(images via: myriorama)

The spined assassin bug is a darkish brown to dull reddish-brown color. The front legs and body are covered in spines. If hungry, the spined assassin bug will resort to cannibalism, eating surrounding siblings. Bites are painful and can cause a burning, itching sensation, as well as swelling at the site of the bite.

African Assassin Bug (Platymeris biguttata)

(images via: bsmith4815, kitlkat and tlindenbaum)

A voracious hunter this insect reputedly has venom ten times deadlier than a cobra. A California zookeeper nearly died while cleaning an enclosure full of these. They are capable of downing prey larger than themselves and are one of the deadliest kinds of insects in the world.

Black Corsair (Melanolestes picipes)

(images via: Dayna R)

They will run down their prey in their hunt for food. They’ve been known to suck the blood of rodents, and even humans. Disturbingly enough, they prefer to go for eyes and lips.

Masked Hunter (Reduvius Personatus)

(images via: imarsman, memanh, collin purrington and wikimedia)

During its immature phases, the legs of this insect contain hairs which pick up lint and dust, making it look like an innocent little fur ball from a distance. They readily hunt other bugs, but will easily bite humans if provoked. Their bites are extremely painful and on par with many forms of snake bite.

I thought that some people might enjoy this particular comic strip :)

prehistoric parody

Just in case of Velociraptor attack...
http://www.velociraptors.info/

Start with a laugh...

I thought you might appreciate this particular comic, for those of you who love cuttlefish. And biology. (if you're wondering- this is from a webcomic strip called xkcd)