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Two Mechanisms For Growth Inhibition By Elevated Transport Of Sugar Phosphates In Escherichia Coli, Robert J. Kadner, G. Patrick Murphy, Craig Stephens

Biology

The Escherichia coli uhp T gene encodes an active transport system for sugar phosphates. When the uhp T gene was carried on a multicopy plasmid, amplified levels of transport activity occurred, and growth of these strains was inhibited upon the addition of various sugar phosphates. Two different mechanisms for this growth inhibition were distinguished. Exposure to glucose-6-phosphate, fructose-6-phosphate or mannose-6-phosphate, which enter directly into the glycolytic pathway, resulted in cessation of growth and substantial loss of viability. Cell killing was correlated with the production of the toxic metabolite, methylglyoxal. In contrast, addition of 2-deoxyglucose-6-phosphate, galactose-6-phosphate, glucosamine-6-phosphate or arabinose-5-phosphate, which do …

Santa Clara Magazine, Volume 35 Number 1, Fall 1992, Santa Clara University

Santa Clara Magazine

11 - SENIOR SEMINAR Elderhostel brings a different kind of student to Santa Clara. By Christine Spielberger '69

14 - DAYS RICH WITH EMPTINESS A noted Catholic writer reflects on his annual retreat to a Trappist abbey, a respite from the daily stress of getting and spending. In a related article, he discusses "The Inner Experience," an unpublished book by Thomas Merton that examines the modern contemplative lifestyle. By Mitch Finley '73

22 - WHAT'S WRONG WITH THIS PICTURE? The image of an all -male Senate committee weighing the merits of Anita Hill 's charges against Clarence Thomas spurred a …

Santa Clara Magazine, Volume 34 Number 4, Summer 1992, Santa Clara University

Santa Clara Magazine

12 - SQUEEZING THE MIDDLE CLASS Gone, in the face of staggering recessionary losses, is the peace of mind that once seemed the virtual birthright of the middle class. By Elizabeth Fernandez '79

18 - A FRAGILE PEACE El Salvador shows a ravaged but hopeful face to a delegation from SCU, Stanford, and the Diocese of San Jose. By Thomas Shanks, S.J.

24 - IT TAKES TEAMWORK Facing fierce global competition, more and more U.S. companies are exploring work teams. By Lisa Agrimonti '87

28 - GIVING TO SANTA CLARA: IT RUNS IN THE FAMILY A tradition of giving and …

Santa Clara Magazine, Volume 34 Number 3, Spring 1992, Santa Clara University

Santa Clara Magazine

12 - EAST L.A. STORY Jesuit-run Dolores Mission Alternative School is a last chance for East L.A.'s troubled teen-agers, many of whom are members of violent Latino gangs. By Rene Romo '86

20 - ONE IS TOO MANY TWO ARE NOT ENOUGH A personal account of one woman's struggle with alcohol addiction. By Lisa Agrimonti '87

24 - UP CLOSE: WITOLD KRASSOWSKI After five years in the Polish Underground Army during WW II, the founder of SCU's Sociology Department came to America and discovered teaching. His 40-year commitment to students has never waivered. By Christine Spielberger '69

28 - WORKING …

Essential Cysteines In 3-Deoxy-D-Arabino-Heptulosonate-7-Phosphate Synthase From Escherichia Coli., Craig Stephens, Ronald Bauerle

Biology

The phenylalanine-sensitive isozyme of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Escherichia coli was inactivated by the sulfhydryl modifying reagents 5,5-dithiobis-(2-nitrobenzoate), bromopyruvate, and N-ethylmaleimide and protected from inactivation by the presence of its metal activator, Mn2+, and substrate, phosphoenolpyruvate. Inactivation by 5,5-dithiobis-(2-nitrobenzoate) was correlated with modification of two of the seven cysteine sulfhydryls of the enzyme monomer. The kinetics of 5,5-dithiobis-(2-nitrobenzoate) modification were altered significantly and distinctively by both substrates (phosphoenolpyruvate and erythrose 4-phosphate), by Mn2+, and by L-phenylalanine, suggesting that ligand binding has significant effects on the conformation of the enzyme. Site-directed mutagenesis was used to create multiple substitutions at the two invariant …

Santa Clara Magazine, Volume 34 Number 2, Winter 1992, Santa Clara University

Santa Clara Magazine

12 - 3 PATHS TO POLITICS Dee Dee Myers '83, Gary Serda '82, and Janet Napolitano '79 have taken three decidedly different roads to political careers. By Kathy Daile-Molle '85

18 - WHAT DO YOU WANT TO BE WHEN YOU GROW UP? Increasingly, people are finding themselves making several career transitions throughout their work lives. By Mike Brozda '76

22 - EL CENTRO: THE EYE OF THE STORM For San Jose's Hispanic community, this mental health clinic, whose counselors are primarily SCU grads, provides a respite from the turbulence of life in a strange culture. By Susan Frey

24 - …