In both yeast and mammalian systems, considerable progress has been made toward the characterization of the transcription factors required for transcription by RNA polymerase III. However, whereas in yeast all of the RNA polymerase III subunits have been cloned, relatively little is known about the enzyme itself in higher eukaryotes.

For example, no higher eukaryotic sequence corresponding to the largest RNA polymerase III subunit is available. Here we describe the isolation of cDNAs that encode the largest subunit of human RNApolymerase III, as suggested by the observations that

(1) antibodies directed against the cloned protein immunoprecipitate an active enzyme whose sensitivity to different concentrations of α-amanitin is that expected for human RNA polymerase III; and

(2) depletion of transcription extracts with the same antibodies results in inhibition of transcription from an RNA polymerase III, but not from an RNA polymerase II, promoter.

Sequence comparisons reveal that regions conserved in the RNA polymerase I, II, and III largest subunits characterized so far are also conserved in the human RNA polymerase III sequence, and thus probably perform similar functions for the human RNA polymerase III enzyme.

Source - http://genome.cshlp.org/content/7/10/1006.abstract?sid=4be18750-d5af-4896-b05e-eeb49c944425

A biochemist and cook explains that cooking is all about chemistry and knowing some facts can help chefs understand why recipes go wrong. Because cooking is essentially a series of chemical reactions, it is helpful to know some basics. For example, plunging asparagus into boiling water causes the cells to pop and result in a brighter green. Longer cooking, however, causes the plant's cell walls to shrink and releases an acid. This turns the asparagus an unappetizing shade of grey.

You love to cook, but have you whipped up some disasters? Even the best recipes can sometimes go terribly wrong. A nationally recognized scientist and chef says knowing a little chemistry could help.

Long before she was a cook, Shirley Corriher was a biochemist. She says science is the key to understanding what goes right and wrong in the kitchen.

"Cooking is chemistry," said Corriher. "It's essentially chemical reactions."

This kind of chemistry happens when you put chopped red cabbage into a hot pan. Heat breaks down the red anthocyanine pigment, changing it from an acid to alkaline and causing the color change. Add some vinegar to increase the acidity, and the cabbage is red again. Baking soda will change it back to blue.

Cooking vegetables like asparagus causes a different kind of reaction when tiny air cells on the surface hit boiling water.

"If we plunge them into boiling water, we pop these cells, and they suddenly become much brighter green," Corriher said.

Longer cooking is not so good. It causes the plant's cell walls to shrink and release acid.

"So as it starts gushing out of the cells, and with acid in the water, it turns cooked green vegetables into [a] yucky army drab," Corriher said.

And that pretty fruit bowl on your counter? "Literally, overnight you can go from [a] nice green banana to an overripe banana," Corriher said.

The culprit here is ethylene gas. Given off by apples and even the bananas themselves, it can ruin your perfect fruit bowl -- but put an apple in a paper bag with an unripe avocado, and ethylene gas will work for you overnight.

"We use this as a quick way to ripen," Corriher said. Corriher says understanding a little chemistry can help any cook.

"You may still mess up, but you know why," she said. When it works, this kind of chemistry can be downright delicious.

WHAT ARE ACIDS AND BASES? An acid is defined as a solution with more positive hydrogen ions than negative hydroxyl ions, which are made of one atom of oxygen and one of hydrogen. Acidity and basicity are measured on a scale called the pH scale. The value of freshly distilled water is seven, which indicates a neutral solution. A value of less than seven indicates an acid, and a value of more than seven indicates a base. Common acids include lemon juice and coffee, while common bases include ammonia and bleach.

WHY DOES FOOD SPOIL? Processing and improper storage practices can expose food items to heat or oxygen, which causes deterioration. In ancient times, salt was used to cure meats and fish to preserve them longer, while sugar was added to fruits to prevent spoilage. Certain herbs, spices and vinegar can also be used as preservatives, along with anti-oxidants, most notably Vitamins C and E. In processed foods, certain FDA-approved chemical additives also help extend shelf life.

Natural antisense transcripts (NATs) have been shown to play important roles in post-transcriptional regulation through the RNA interference pathway. We have combined pyrophosphate-based high-throughput sequencing and computational analysis to identify and analyze, in genome scale, cis-NAT and trans-NAT small RNAs that are derived under normal conditions and in response to drought and salt stresses in the staple plant Oryza sativa.

Computationally, we identified 344 cis-NATs and 7142 trans-NATs that are formed by protein-coding genes. From the deep sequencing data, we found 108 cis-NATs and 7141trans-NATs that gave rise to small RNAs from their overlapping regions. Consistent with early findings, the majority of these 108 cis-NATs seem to be associated with specific conditions or developmental stages. Our analyses also revealed several interesting results.

The overlapping regions of the cis-NATs and trans-NATs appear to be more enriched with smallRNA loci than non-overlapping regions. The small RNAs generated from cis-NATs and trans-NATs have a length bias of 21 nt, even though their lengths spread over a large range. Furthermore, >40% of the small RNAs from cis-NATs and trans-NATs carry an A as their 5′-terminal nucleotides.

A substantial portion of the transcripts are involved in both cis-NATs and trans-NATs, and many trans-NATs can form many-to-many relationships, indicating that NATs may form complex regulatory networks in O. sativa. This study is the first genome-wide investigation of NAT-derived small RNAs in O. sativa. It reveals the importance of NATs in biogenesis of small RNAs and broadens our understanding of the roles of NAT-derived smallRNAs in gene regulation, particularly in response to environmental stimuli.

Source - http://genome.cshlp.org/content/19/1/70.abstract?sid=40206306-7c2e-4b18-96b3-8319fa594a4b

Omega-3 fatty acids, commonly found in fish, appears to play a significant role in improving nervous system function, reveals a new study.

The researchers insist two omega-3 fatty acids – docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been found to avoid sensory overload, maybe by maintaining nerve-cell membranes.
The finding connects low omega-3s to the information-processing problems found in people with schizophrenia; bipolar, obsessive-compulsive, and attention-deficit hyperactivity disorders; Huntington’s disease; and other afflictions of the nervous system.
"It is an uphill battle now to reverse the message that ‘fats are bad,’ and to increase omega-3 fats in our diet," said Norman Salem Jr., PhD, who led this study at the Laboratory of Membrane Biochemistry and Biophysics at the National Institute on Alcohol Abuse and Alcoholism.
The body cannot make these essential nutrients from scratch. It gets them by metabolizing their precursor, á-linolenic acid (LNA), or from foods or dietary supplements with DHA and EPA in a readily usable form.
"Humans can convert less than one percent of the precursor into DHA, making DHA an essential nutrient in the human diet," said Irina Fedorova, PhD, one of the paper’s co-authors.
EPA is already known for its anti-inflammatory and cardiovascular effects, but DHA makes up more than 90 percent of the omega-3s in the brain (which has no EPA), retina and nervous system in general.
During the study, the researchers fed four different diets with no or varying types and amounts of omega-3s to four groups of pregnant mice and then their offspring.
They measured how the offspring, once grown, responded to a classic test of nervous-system function in which healthy animals are exposed to a sudden loud noise. Normally, animals flinch. However, when they hear a softer tone in advance, they flinch much less.
It appears that normal nervous systems use that gentle warning to prepare instinctively for future stimuli, an adaptive process called sensorimotor gating.
The mice raised on DHA and EPA showed normal, adaptive sensorimotor gating by responding in a significantly calmer way to the loud noises that followed soft tones.
The research is published in journal Behavioural Neuroscience .

Source: http://timesofindia.indiatimes.com/life/health-fitness/health/Fish-can-help-improve-nervous-system-function/articleshow/5347748.cms