Biotechnology a sudden new biological revolution

Biotechnology seems to be leading a sudden new biological revolution. It has brought us to the brink of a world of "engineered" products that are based in the natural world rather than on chemical and industrial processes.

Biotechnology has been described as "Janus-faced." This implies that there are two sides. On one, techniques allow DNA to be manipulated to move genes from one organism to another. On the other, it involves relatively new technologies whose consequences are untested and should be met with caution. The term "biotechnology" was coined in 1919 by Karl Ereky, an Hungarian engineer. At that time, the term meant all the lines of work by which products are produced from raw materials with the aid of living organisms. Ereky envisioned a biochemical age similar to the stone and iron ages.

A common misconception among teachers is the thought that biotechnology includes only DNA and genetic engineering. To keep students abreast of current knowledge, teachers sometimes have emphasized the techniques of DNA science as the "end-and-all" of biotechnology. This trend has also led to a misunderstanding in the general population. Biotechnology is NOT new. Man has been manipulating living things to solve problems and improve his way of life for millennia. Early agriculture concentrated on producing food. Plants and animals were selectively bred, and microorganisms were used to make food items such as beverages, cheese, and bread.

The late eighteenth century and the beginning of the nineteenth century saw the advent of vaccinations, crop rotation involving leguminous crops, and animal drawn machinery. The end of the nineteenth century was a milestone of biology. Microorganisms were discovered, Mendel's work on genetics was accomplished, and institutes for investigating fermentation and other microbial processes were established by Koch, Pasteur, and Lister.

Biotechnology at the beginning of the twentieth century began to bring industry and agriculture together. During World War I, fermentation processes were developed that produced acetone from starch and paint solvents for the rapidly growing automobile industry. Work in the 1930s was geared toward using surplus agricultural products to supply industry instead of imports or petrochemicals. The advent of World War II brought the manufacture of penicillin. The biotechnical focus moved to pharmaceuticals. The "cold war" years were dominated by work with microorganisms in preparation for biological warfare, as well as antibiotics and fermentation processes.

Biotechnology is currently being used in many areas including agriculture, bioremediation, food processing, and energy production. DNA fingerprinting is becoming a common practice in forensics. Similar techniques were used recently to identify the bones of the last Czar of Russia and several members of his family. Production of insulin and other medicines is accomplished through cloning of vectors that now carry the chosen gene. Immunoassays are used not only in medicine for drug level and pregnancy testing, but also by farmers to aid in detection of unsafe levels of pesticides, herbicides, and toxins on crops and in animal products. These assays also provide rapid field tests for industrial chemicals in ground water, sediment, and soil. In agriculture, genetic engineering is being used to produce plants that are resistant to insects, weeds, and plant diseases.

A current agricultural controversy involves the tomato. A recent article in the New Yorker magazine compared the discovery of the edible tomato that came about by early biotechnology with the new "Flavr-Savr" tomato brought about through modern techniques. In the very near future, you will be given the opportunity to bite into the Flavr-Savr tomato, the first food created by the use of recombinant DNA technology ever to go on sale.

What will you think as you raise the tomato to your mouth? Will you hesitate? This moment may be for you as it was for Robert Gibbon Johnson in 1820 on the steps of the courthouse in Salem, New Jersey. Prior to this moment, the tomato was widely believed to be poisonous. As a large crowd watched, Johnson consumed two tomatoes and changed forever the human-tomato relationship. Since that time, man has sought to produce the supermarket tomato with that "backyard flavor." Americans also want that tomato available year-round.

New biotechnological techniques have permitted scientists to manipulate desired traits. Prior to the advancement of the methods of recombinant DNA, scientists were limited to the techniques of their time - cross-pollination, selective breeding, pesticides, and herbicides. Today's biotechnology has its "roots" in chemistry, physics, and biology . The explosion in techniques has resulted in three major branches of biotechnology: genetic engineering, diagnostic techniques, and cell/tissue techniques.

http://www.accessexcellence.org/RC/AB/BC/Overview_and_Brief_History.html

Evolution of DNA metabolism

Further information: RNA world hypothesis

DNA contains the genetic information that allows all modern living things to function, grow and reproduce. However, it is unclear how long in the 4-billion-year history of life DNA has performed this function, as it has been proposed that the earliest forms of life may have used RNA as their genetic material.^[81][93] RNA may have acted as the central part of early cell metabolism as it can both transmit genetic information and carry out catalysis as part of ribozymes.^[94] This ancient RNA world where nucleic acid would have been used for both catalysis and genetics may have influenced the evolution of the current genetic code based on four nucleotide bases. This would occur since the number of unique bases in such an organism is a trade-off between a small number of bases increasing replication accuracy and a large number of bases increasing the catalytic efficiency of ribosomes.^[95]

Unfortunately, there is no direct evidence of ancient genetic systems, as recovery of DNA from most fossils is impossible. This is because DNA will survive in the environment for less than one million years and slowly degrades into short fragments in solution.^[96] Claims for older DNA have been made, most notably a report of the isolation of a viable bacterium from a salt crystal 250-million years old,^[97] but these claims are controversial.^[98][99]

http://en.wikipedia.org/wiki/DNA

DNA genetic material

	We All Share the Same Building Blocks
		DNA is a winning formula for packaging genetic material. Therefore almost all organisms – bacteria, plants, yeast and animals – carry genetic information encapsulated as DNA. One exception is some viruses that use RNA instead. Different species need different amounts of DNA. Therefore the copying of the DNA that precedes cell division differs between organisms. For example, the DNA in E. coli bacteria is made up of 4 million base pairs and the whole genome is thus one millimeter long. The single-cell bacterium can copy its genome and divide into two cells once every 20 minutes. The DNA of humans, on the other hand, is composed of approximately 3 billion base pairs, making up a total of almost a meter-long stretch of DNA in every cell in our bodies. In order to fit, the DNA must be packaged in a very compact form. In E. coli the single circular DNA molecule is curled up in a condensed fashion, whereas the human DNA is packaged in 23 distinct chromosome pairs. Here the genetic material is tightly rolled up on structures called histones.
		A New Biological Era
		This knowledge of how genetic material is stored and copied has given rise to a new way of looking at and manipulating biological processes, called molecular biology. With the help of so-called restriction enzymes, molecules that cut the DNA at particular stretches, pieces of DNA can be cut out or inserted at different places. In basic science, where you want to understand the role of all the different genes in humans and animals, new techniques have been developed. For one thing, it is now possible to make mice that are genetically modified and lack particular genes. By studying these animals scientists try to figure out what that gene may be used for in normal mice. This is called the knockout technique, since stretches of DNA have been taken away, or knocked out. Scientists have also been able to insert new bits of DNA into cells that lack particular pieces of genes or whole genes. With this new DNA, the cell becomes capable of producing gene products it could not make before. The hope is that, in the future, diseases that arise due to the lack of a particular protein could be treated by this kind of gene therapy.
		Was Franklin Nominated?
Rosalind Franklin. Photo: Cold Spring Harbor Laboratory Archives		Many voices have argued that the Nobel Prize should also have been awarded to Rosalind Franklin, since her experimental data provided a very important piece of evidence leading to the solving of the DNA structure. In a recent interview in the magazine Scientific American, Watson himself suggested that it might have been a good idea to give Wilkins and Franklin the Nobel Prize in Chemistry, and him and Crick the Nobel Prize in Physiology or Medicine – in that way all four would have been honored. Rosalind Franklin died in 1958. As a rule only living persons can be nominated for the the Nobel Prize, so the 1962 Prize was out of the question. But she may have been a nominee while she was still alive. The Nobel archives, that among other things contain the nominations connected to the prizes, are held closed. But 50 years after a particular prize had been awarded, the archives concerning the nominees are released. Therefore, in 2008 it will be possible to see whether Rosalind Franklin was ever a nominee for the Nobel Prize concerning the DNA helix.
		The DNA-Helix
The sugar-phosphate backbone is on the outside and the four different bases are on the inside of the DNA molecule.		The two strands of the double helix are anti-parallel, which means that they run in opposite directions. The sugar-phosphate backbone is on the outside of the helix, and the bases are on the inside. The backbone can be thought of as the sides of a ladder, whereas the bases in the middle form the rungs of the ladder. Each rung is composed of two base pairs. Either an adenine-thymine pair that form a two-hydrogen bond together, or a cytosine-guanine pair that form a three-hydrogen bond. The base pairing is thus restricted. This restriction is essential when the DNA is being copied: the DNA-helix is first "unzipped" in two long stretches of sugar-phosphate backbone with a line of free bases sticking up from it, like the teeth of a comb. Each half will then be the template for a new, complementary strand. Biological machines inside the cell put the corresponding free bases onto the split molecule and also "proof-read" the result to find and correct any mistakes. After the doubling, this gives rise to two exact copies of the original DNA molecule. The coding regions in the DNA strand, the genes, make up only a fraction of the total amount of DNA. The stretches that flank the coding regions are called introns, and consist of non-coding DNA. Introns were looked upon as junk in the early days. Today, biologists and geneticists believe that this non-coding DNA may be essential in order to expose the coding regions and to regulate how the genes are expressed.

http://nobelprize.org/educational_games/medicine/dna_double_helix/readmore.html

DNA

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

Chemically, DNA is a long polymer of simple units called nucleotides, with a backbone made of sugars and phosphate groups joined by ester bonds. Attached to each sugar is one of four types of molecules called bases. It is the sequence of these four bases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA, in a process called transcription.

Within cells, DNA is organized into structures called chromosomes. These chromosomes are duplicated before cells divide, in a process called DNA replication. Eukaryotic organisms (animals, plants, and fungi) store their DNA inside the cell nucleus, while in prokaryotes (bacteria and archae) it is found in the cell's cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.

The structure of part of a DNA double helix


http://en.wikipedia.org/wiki/DNA

Science, Medicine, Technology

Skeleton key

We knew our bones were busy producing blood cells and platelets, storing and releasing calcium into the bloodstream, and protecting our squishy innards. Now Columbia scientists have discovered an entirely new function of the skeleton: They say it also acts as an endocrine organ, producing a hormone that helps us process sugar.

Hormones, which control everything from growth to metabolism to reproduction, typically come from our glands or sex organs; a few have been traced to the heart, abdominal organs, and skin. They weren’t known to come from bone, until now. A research team led by Gerard Karsenty, chair of the Department of Genetics and Development at Columbia’s College of Physicians and Surgeons, has found that osteocalcin, a hormone released by bone cells, directly regulates the metabolism of glucose in mice. Shortages of osteocalcin, the researchers say, seem to cause obesity and type 2 diabetes in the animals.

There is “no guarantee” that the hormone behaves similarly in humans, “but osteocalcin exists in humans,” Karsenty says. “It operates in a region where type 2 diabetes genes are known to be present, and its levels vary with sugar metabolism, so we are cautiously optimistic.”

In mice, at least, osteocalcin controls blood sugar by increasing the proliferation of insulin-producing beta cells in the pancreas, signaling those beta cells to produce more insulin and triggering fat cells to release another hormone, called adiponectin, that enhances insulin sensitivity. Mice and men both rely on insulin to sweep sugar from the blood and into cells, where it is used as energy or stored as fat.

If osteocalcin has comparable effects on people, Karsenty says, its discovery could lead to a cure for the 20 million Americans with diabetes, in whom insufficient insulin levels can chronically elevate blood glucose, heightening the risk of heart disease, kidney failure, and blindness.

But the discovery that the skeleton interacts with other organs is stunning in itself, prompting scientists to reconsider the skeleton’s purpose. “It certainly has caused quite a stir,” Graham Williams, an endocrinology expert at Imperial College London, told the Web site Nature News recently. “People think it’s a novel idea, and likely to turn out to be a paradigm shift.”

Karsenty and his team had been searching for a skeletal hormone that communicates with fat since demonstrating in 2002 that leptin, a hormone produced by fat cells, is crucial to regulating bone mass. Given that most bodily systems work as feedback loops, if fat signals bone, it stood to reason that bone might also signal fat. Osteocalcin, already known to be lower in diabetics thanks to earlier studies investigating the link between diabetes and an increased incidence of bone fractures, was thrown into the mix of suspects.

The researchers found that mice genetically programmed to have high levels of osteocalcin don’t gain weight or become diabetic even when fed a high-fat diet, while mice manipulated to lack osteocalcin become fat, secrete less insulin and adiponectin, produce fewer beta cells, and develop type 2 diabetes.

Karsenty says his lab will continue to investigate the role of osteocalcin in glucose metabolism, in animals as well as humans, with an eye toward developing novel therapies for preventing obesity, type 2 diabetes, and related disorders.

http://www.columbia.edu/cu/alumni/Magazine/Fall2007/ScienceMedTech.html