Editor's note: Science Scan is a roundup of recently published biotechnology-relevant research.
Decaffeinated coffee could be grown on trees - anyway, on bushes - reports a "Brief Communication" in Nature dated June 19, 2003. Japanese geneticists have created genetically modified transgenic plants (Coffea canephora) with reduced caffeine content.
Their one-page communication is headed, briefly, "Producing decaffeinated coffee plants." The co-authors are researchers at the Nara Institute of Science and Technology in Nara, Japan.
At present, they point out, coffee is decaffeinated via expensive industrial processes, and the flavor of the finished product is poor. The resulting compromised flavor can send real java connoisseurs racing for the raw product. Now the co-authors report employing a technique called RNA interference to reduce the activity of key caffeine-making genes in coffee plants. This lowers the caffeine content by up to 70 percent, indicating that it should be feasible to produce coffee beans that are intrinsically deficient in caffeine.
The popular demand by aficionados for "decaf" is going up. The reason? A full-strength natural brew can raise blood pressure, trigger palpitations and cause insomnia in some sensitive individuals. Others favor a full-flavored cup at bedtime, without the risk of a sleepless night. Three N-methyltransferase enzymes are implicated in caffeine biosynthesis in coffee plants. They are theobromine synthase and caffeine synthase, both of which add methyl groups to the third, xanthosine, in converting it into caffeine. Genetically modified coffee plants may offer a cheaper, more flavorsome alternative to the conventional decaf cuppa.
The paper's co-authors transformed Agrobacterium tumefaciens cells with an untranslated region of RNA short and long fragments and used them to transform natural Coffea canephora. After three or four months of culture, it was possible to raise seedlings, the Nature paper reports. More than 35 transgenic somatic seedlings were obtained from each transformant. The phenotypes were comparatively normal, when compared with the wild-type plant.
The co-authors are now applying their RNA technique to Coffea arabica, which yields high-quality Arabica coffee alkaloid, and accounts for roughly 70 percent of the world market. "Our method," they conclude, "not only shortens the breeding period, which is more than 25 years for conventional crossing, but also opens the way to develop new species of coffee plant."
Pfizer Researchers Seek Relief From Arthritis In Prostaglandin E2 Treatment Option
A molecule responsible for the pain and inflammation of conditions like rheumatoid arthritis may be thwarted without the side effects associated with current treatments. Anti-inflammatory drugs such as aspirin block prostaglandin E2 (PGE2), a potent mediator of inflammation. Unfortunately, these treatments also inhibit other related molecules, resulting in unwanted side effects such as ulcers and constipation.
In search of a more specific treatment option, 12 company researchers at Pfizer Global R&D, Groton Laboratories in Groton, Conn., co-authored a paper in the current Proceedings of the National Academy of Sciences (PNAS) titled "Impaired inflammatory and pain responses in mice lacking an inducible prostaglandin E synthase." They focused on prostaglandin E synthase-1 an enzyme that catalyzes PGE2 formation. The co-authors bred a line of mice lacking the gene for this enzyme. The animals were healthy and fertile. However, when the team exposed the enzyme-deficient mice to different inflammatory stimuli, the mice exhibited a markedly reduced inflammatory response, compared to a bunch of normal rodents.
The co-authors also induced a disease similar to rheumatoid arthritis in both groups of mice. However, the enzyme-free ones showed much less joint deterioration and inflammation. In addition, the enzyme-free mice did not appear to experience inflammation-induced pain. Future research to find ways of inhibiting prostaglandin E synthesis could offer a more precise treatment option for diseases like rheumatoid arthritis.
Precision and selectivity are the mantra of today's molecular medicine. In this context, PGE2 actions range from protecting gastrointestinal mucosa to regulating smooth muscle and fever. For example, set a steep challenge for designer drug hunters to achieve. The findings of the Pfizer team raise hope that new classes of drugs targeting microsomal PGE2 synthase-1 can be developed for the treatment of chronic inflammatory diseases, as well as their associated pain.
A Report On Prostaglandin E In The Lancet Tells How Kids With Type I Diabetes Risk Type II
A preliminary study in The Lancet, released May 29, 2003, suggests that offspring of mothers with Type I diabetes could be at an increased risk of Type II disease in adult life - even in the absence of inherited types I or II. Type Ii diabetes generally occurs in adulthood and is caused by both genetic and environmental factors (such as obesity).
Co-authors at the Saint-Louis Hospital in Paris assessed whether prenatal exposure to a diabetic environment is associated with metabolic disorders in later adult life, which can lead to Type II diabetes. They also probed abnormalities that are predisposing to Type II diabetes in offspring of mothers or fathers with Type I diabetes. Insulin production in response to oral and intravenous glucose was measured in 15 nondiabetic adult offspring of mothers with Type I diabetes and 16 offspring of Type I diabetic fathers (the control group). None of the participants had inherited Type I diabetes.
The paper's senior author commented, "Exposure to a diabetic environment in utero is associated with increased occurrence of impaired glucose tolerance and a defective insulin secretory response in adult offspring, independent of genetic predisposition to Type II diabetes. Epidemiological studies," he concluded, "are needed to confirm our observations before therapeutic strategies can be devised."
An editorial accompanying the paper made the point that "Type II diabetes (insulin-independent) is a growing epidemic in developed countries, but the present burden may pale in comparison with the forecast estimated for developing countries during the next few decades. There are several factors conspiring to make diabetes and its precursors, glucose intolerance and insulin resistance, such a pervasive issue affecting both the present and future health of the world's population. The first relates to the global aging of that population, exposing more people to the ravages of the disease; and the second involves the dramatic adverse changes in diet and exercise patterns."