Editor's note: Science Scan is a quick round-up of recently published,biotechnology-related research.
Genetically Engineered Foods, Any One?Surveyed Consumers Couldn't Care Less
Public opinion polls of some 4,000 people over the last four yearsencountered unawareness and indifference, rather than hostility, tothe coming wave of biotechnology-altered foods.
Sociologist Thomas Hoban of North Carolina State University inRaleigh on Sunday, informed the American Chemical Society (ACS)meeting in New Orleans, that his surveys found, "the use ofbiotechnology is really not an issue for most consumers."
Hoban told his ACS audience that "despite all the media coverageand attention given to biotechnology, public awareness has not goneup. It's still very low. But when we ask them," he added, "how likelythey would be to buy a new, better-tasting tomato, or other kinds ofbiotech food products, most people say they would accept it and feelcomfortable with it."
Thus, he pointed out, "the use of the growth hormone BST (bovinesomatotropin) to increase dairy cow milk yields, at one time socontentious, has virtually turned into a non-event."
The ACS's 211th national meeting will continue in New Orleansthrough today.
Naturally caffeine-free coffee is only one of many bio-foods nowmoving through the pipeline, reported food scientist Susan Harlander,vice-president of Green Giant research and development at thePillsbury Technology Center in Minneapolis. Other products, she toldSunday's session of the ACS meeting, include vegetable oil lower insaturated fat, and genetically engineered potatoes that absorb less fatwhen fried.
Spuds, squash, onions and garlic vaccinated against plant viruses arein field trials, Harlander noted, as are tomatoes, potatoes, cotton andcorn that express insecticidal genes. And DNA Plant TechnologiesCorp. of Cinnaminson, N.J. is test-marketing stringless celery.
Dental Researchers Find New Marker ToDiagnose, Predict, Prevent Autoimmune Diabetes
Close to 1 million people in the U.S. alone have to shoot up insulinevery day in order to stay alive. They suffer from what used to becalled "juvenile" diabetes, because it usually surfaces in childhood.For some years before it's diagnosed, the seeds of insulin-dependentdiabetes mellitus (IDDM) lurk beneath that surface.
Diabetologists in many countries are searching for clues _ markers_ to predict that susceptibility, so they can take early steps tomitigate or ward off the full-blown disease.
People with IDDM _ Type 1 diabetes _ must self-inject drug-storeinsulin because their immune system views the insulin their ownpancreas makes as foreign, and destroys it with autoimmuneantibodies.
The current Proceedings of the National Academy of Sciences(PNAS) dated March 19, reports a newly discovered protein,produced in the pancreas and in the brain. Its discoverers at NationalInstitutes of Health's National Institute of Dental Research (NIDR) inBethesda, Md., propose that this novel marker (jointly with otherknown proteins) could sharpen diagnosis of IDDM patients, identifythose at risk of developing the disease, possibly prevent its onset andhelp unmask the root cause of the disease process.
Their PNAS report is titled: "Identification of a secondtransmembrane protein tyrosine phosphatase, IA-2b, as anautoantigen in insulin-dependent diabetes mellitus: Precursor of the37-kDa tryptic [trypsin-related] fragment."
What tooth-and-gum researchers at the NIDR are doing in thepancreas is readily explained: They are investigating the molecularbiology of diabetes, because IDDM, among its protean complications_ e.g., blindness, kidney and heart disease, unhealing foot ulcers _is known to increase the risk of periodontal (gum) disease and toothloss.
X-Ray Crystallography Arms MedicinalChemists To Resist Bacterial Drug Resistance
Our outgoing 20th century bequeaths to its incoming 21st a planetfulof pathogens increasingly, and alarmingly, resistant to antibiotics.
Hailed as "miracle drugs" half a century ago, penicillin and itsfollow-on antibacterials promised to rid the earth of infection. It wasa case of "promises, promises," largely broken by the very physicianswho made them.
Their egregious over-use of the proliferating pharmacopeia ofantibiotics helped educate the germs in how to beat them at their owngame. How the bugs do it seems a miracle in itself, and a baffling oneuntil lately. (See BioWorld Today, Jan. 12, 1996, p. 1.)
Consider the bacterium Streptococcus pneumoniae, which causespneumonia. Penicillin originally bid fair to wipe that infection off themap. The drug's target is a bacterial enzyme, PBP2x, a molecularmaster mason in building the bacterium's cell wall.
Eventually, evolution abetted by too much penicillin, mutatedPBP2x, thus rendering S. pneumoniae resistant to the antibiotic.
Up to now, the counter-punch to such resistance has been drugdiscovery _ medicinal chemists compounding yet another antibioticto start the cycle all over again.
Now the structural biologists are taking a hand in this zero-sum duel.
In the March issue of Nature Structural Biology, a team of X-raycrystallographers from France and Germany depict a b-lactamanalogue of penicillin complexed with the bacterial enzyme's activesite, thus blocking its brick-laying of the cell wall.
Their paper's title: "X-ray structure of Streptococcus pneumoniaePBP2x, a primary penicillin target enzyme."
This new insight points toward more efficient antibiotics, hence,lower doses and less toxicity.
But putting penicillin's back up against the wall is only one of S.pneumoniae's resistance strategies. Another is to destroy theantibiotic outright before it has the chance to inhibit PBP2x. Here thegerm's weapon is a specific anti-antibiotic enzyme it has evolved, b-lactamase.
The scientists' tit for that tat is a b-lactam-blocker blocker namedBLIP _ beta-lactam inhibiting protein. Its authors are Canadian,French, Israeli, British and American, presenting two papers in thesame Nature Structural Biology. One bears the title: "A potent newmode of b-lactam inhibition revealed by the 1.7 X-raycrystallographic structure of the TEM-1-BLIP complex;" the other,"Molecular docking programs successfully predict the binding of a b-lactamase inhibitory protein to TEM-1 b-lactamase."
But BLIP is a bulky molecule, hard to push into a patient, evenharder to smuggle inside the germ. The X-ray images clearly showhow BLIP grabs the bacterial enzyme in a pincer movement, andsuggest the pattern of specific new drugs. n
_ Compiled by David N. Leff, Science Editor
(c) 1997 American Health Consultants. All rights reserved.