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Can enzyme supplements really keep hair from going gray? - USA TODAY

Can enzyme supplements really keep hair from going gray? - USA TODAY | Biology | Scoop.it
Can enzyme supplements really keep hair from going gray?
USA TODAY
Anderson Cooper, Emmylou Harris and Toni Morrison are among famous faces known also for their striking silver tresses.
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How first life emerged from deep-sea rocks

How first life emerged from deep-sea rocks | Biology | Scoop.it
The origin of ion-pumping proteins could explain how life began in, and escaped from, undersea thermal vents.

 

Rocks, water and hot alkaline fluid rich in hydrogen gas spewing out of deep-sea vents: this recipe for life has been championed for years by a small group of scientists.  Now two of them have fleshed out the detail on how the first cells might have evolved in these vents, and escaped their deep sea lair. Nick Lane at University College London and Bill Martin at the University of Düsseldorf in Germany think the answer to how life emerged lies in the origin of cellular ion pumps, proteins that regulate the flow of ions across the cell's membrane, the barrier that separates it from the outside world.

 

In all cells today, an enzyme called ATP synthase uses the energy from the flow of ions across membranes to produce the universal energy-storage molecule ATP. This essential process depends in turn on ion-pumping proteins that generate these gradients. But this creates a chicken-and-egg problem: cells store energy by means of proteins that make ion gradients, but it takes energy to make the proteins in the first place. Lane and Martin argue that hydrogen-saturated alkaline water meeting acidic oceanic water at underwater vents would produce a natural proton gradient across thin mineral 'walls' in rocks that are rich in catalytic iron–sulphur minerals. This set-up could create the right conditions for converting carbon dioxide and hydrogen into organic carbon-containing molecules, which can then react with each other to form the building blocks of life such as nucleotides and amino acids.

 

The rocks of deep-sea thermal vents contain labyrinths of these tiny thin-walled pores, which could have acted as 'proto-cells', both producing a proton gradient and concentrating the simple organic molecules formed, thus enabling them eventually to generate complex proteins and the nucleic acid RNA. These proto-cells were the first life-forms, claim Lane and Martin.


Via Dr. Stefan Gruenwald
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How DNA repair helps prevent cancer

How DNA repair helps prevent cancer | Biology | Scoop.it

The biological information that makes us unique is encoded in our DNA. DNA damage is a natural biological occurrence that happens every time cells divide and multiply. External factors such as overexposure to sunlight can also damage DNA.

 

Michael Feig, professor of biochemistry and molecular biology at Michigan State University, studies the proteins MutS and MSH2-MSH6, which recognize defective DNA and initiate DNA repair. Natural DNA repair occurs when proteins like MutS (the primary protein responsible for recognizing a variety of DNA mismatches) scan the DNA, identify a defect, and recruit other enzymes to carry out the actual repair.

 

“The key here is to understand how these defects are recognized,” Feig explained. “DNA damage occurs frequently and if you couldn’t repair your DNA, then you won’t live for very long.” This is because damaged DNA, if left unrepaired, can compromise cells and lead to diseases such as cancer.

 

DNA bending is believed to facilitate the initial recognition of the mismatched base for repair. The repair efficiencies are dependent on both the mismatch type and neighboring nucleotide sequence. We have studied bending of several DNA duplexes containing canonical matches: A:T and G:C; various mismatches: A:A, A:C, G:A, G:G, G:T, C:C, C:T, and T:T; and a bis-abasic site: X:X. Free-energy profiles were generated for DNA bending using umbrella sampling. The highest energetic cost associated with DNA bending is observed for canonical matches while bending free energies are lower in the presence of mismatches, with the lowest value for the abasic site. In all of the sequences, DNA duplexes bend toward the major groove with widening of the minor groove.

 

For homoduplexes, DNA bending is observed to occur via smooth deformations, whereas for heteroduplexes, kinks are observed at the mismatch site during strong bending. In general, pyrimidine:pyrimidine mismatches are the most destabilizing, while purine:purine mismatches lead to intermediate destabilization, and purine:pyrimidine mismatches are the least destabilizing. The ease of bending is partially correlated with the binding affinity of MutS to the mismatch pairs and subsequent repair efficiencies, indicating that intrinsic DNA bending propensities are a key factor of mismatch recognition.

 

The biological repair machinery seems to take advantage of this propensity by ‘testing’ DNA to determine whether it can be bent easily. If that is the case, the protein has found a mismatch and repair is initiated.

 

“When the MutS protein is deficient in certain people, they have a high propensity to develop certain types of cancer,” Feig said. “We’re interested in understanding, first of all, how exactly this protein works. The long-term idea is to develop strategies for compensating for this protein, basically substituting some other mechanism for recognizing defective DNA and enabling repair.”

The strongest link between diseases and defects from the MutS protein has been made for a specific type of genetically inherited colon cancer.

 

“If an essential protein like MutS is missing or less than adequate, then the cells will not behave in a normal way,” he explained. “They will turn cancerous. The cells will refuse to die and proliferate in an uncontrollable state.”

 

In these cases, cancer is not a result of damaged DNA, but occurs because of a problem in the DNA repair mechanism itself.

 

“It probably has effects on many other cancers as well, because all the cancers are ultimately linked to defective DNA,” he said. “If DNA damage is not recognized and repaired in time then it can lead to any type of cancer. It is a fairly generic mechanism.”

 

According to Matt Cowperthwaite, TACC’s medical informatics programs coordinator, Feig’s research is enormously important for advancing our understanding of how cells repair the mistakes that inevitably occur during DNA replication. “For the first time, we have a mechanistic insight of how MutS finds mutations. This is extremely important research because the process of mutation underlies some of the deadliest diseases to affect humans, such as cancer.”

 

Research in this area, being very fundamental in nature, throws up many challenges, but its potential in future impact, Feig believes, is tremendous.

 


Via Dr. Stefan Gruenwald
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A hidden genetic code for better designer genes

A hidden genetic code for better designer genes | Biology | Scoop.it

Scientists routinely seek to reprogram bacteria to produce proteins for drugs, biofuels and more, but they have struggled to get those bugs to follow orders. But a hidden feature of the genetic code, it turns out, could get bugs with the program. The feature controls how much of the desired protein bacteria produce, a team from the Wyss Institute for Biologically Inspired Engineering at Harvard University reported in the September 26 online issue of Science.

The findings could be a boon for biotechnologists, and they could help synthetic biologists reprogram bacteria to make new drugs and biological devices.

 

By combining high-speed "next-generation" DNA sequencing and DNA synthesis technologies, Sri Kosuri, Ph.D., a Wyss Institute staff scientist, George Church, Ph.D., a core faculty member at the Wyss Institute and professor of genetics at Harvard Medical School, and Daniel Goodman, a Wyss Institute graduate research fellow, found that using more rare words, or codons, near the start of a gene removes roadblocks to protein production.

"Now that we understand how rare codons control gene expression, we can better predict how to synthesize genes that make enzymes, drugs, or whatever you want to make in a cell," Kosuri said.

 

To produce a protein, a cell must first make working copies of the gene encoding it. These copies, called messenger RNA (mRNA), consist of a specific string of words, or codons. Each codon represents one of the 20 different amino acids that cells use to assemble proteins. But since the cell uses 61 codons to represent 20 amino acids, many codons have synonyms that represent the same amino acid.

 

In bacteria, as in books, some words are used more often than others, and molecular biologists have noticed over the last few years that rare codons appear more frequently near the start of a gene. What's more, genes whose opening sequences have more rare codons produce more protein than genes whose opening sequences do not.

 

No one knew for sure why rare codons had these effects, but many biologists suspected that they function as a highway on-ramp for ribosomes, the molecular machines that build proteins. According to this idea, called the codon ramp hypothesis, ribosomes wait on the on-ramp, then accelerate slowly along the mRNA highway, allowing the cell to make proteins with all deliberate speed. But without the on-ramp, the ribosomes gun it down the mRNA highway, then collide like bumper cars, causing traffic accidents that slow protein production. Other biologists suspected rare codons acted via different mechanisms. These include mRNA folding, which could create roadblocks for ribosomes that block the highway and slow protein production.


Via Dr. Stefan Gruenwald
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Healing the Planet Through Photosynthesis and Carbon Sequestration

Healing the Planet Through Photosynthesis and Carbon Sequestration | Biology | Scoop.it
Healing the Planet Through Photosynthesis and Carbon Sequestration · Global Warming/Climate Change, Livestock, Soil Biology, Soil Composition, Soil Rehabilitation — by Mark Hertsgaard September 19, 2013.
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Some Rattlesnakes Losing Their Warning Rattle In S. Dakota

Some Rattlesnakes Losing Their Warning Rattle In S. Dakota | Biology | Scoop.it
There are few things more chilling than the sound of a nearby rattlesnake. That distinctive sound serves as a warning that trouble could be on the way.
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