Proceedings of the 22nd Annual Meeting, Southern Soybean Disease Workers (February 20-22, 1995, St. Louis, Missouri)

Contents Business session Soybean Disease Loss Estimate for the Southern United States during 1994. JA Wrather Treasurer report. GG Hammes SSDW Committee Chairmen for 1994-1995 Graduate student papers Host preference of Rotylenchulus reniformis for weed species common to Louisiana soybean. CH Carter, EC McGawley, and JS Russin Development of an immunoassay for Heterodera glycines eggs. MJ Kennedy, JE Schoelz, TL Niblack, PA Donald Effects of delayed planting and host susceptibility on colonization of soybean by Calonectria crotalariae and development of red crown rot. PU Kuruppu, JS Russin, and EC McGawley Effects of long-term corn/soybean rotation on pathogenicity of Pythium populations on soybean. BQ Zhang and XB Yang Contributed papers Possible shift to more virulent Phytophthora races in Mississippi. GL Sciumbato and BL Keeling The relationship between trehalose content and dormancy of soybean cyst nematode, Heterodera glycines. JH Yen, AL Karr, TL Niblack, and WJ Weibold Fertilization effects on Sudden Death Syndrome (SDS) in soybeans. MA Newman, AY Chambers, and DD Howard Screening southern soybean cultivars for reaction to aerial blight. BG Harville, JS Russin, and RJ Habetz Comparison of continuous soybean, fallow, and rotation with sorghum-sudan grass hybrid for nematode control in a field infested with root-knot and soybean cyst nematodes. R Rodríguez-Kábana, DB Weaver, and EL Carden Recent progress in identifying soybean cultivars field tolerance of Macrophomina phaseolina. GS Smith and ON Carvil Major soybean diseases in Brazil. JT Yorinori Pre- and post-infection efficacy of benomyl for the control of stem canker of soybean. JC Rupe and CM Becton Comparison of continuous soybean and rotation with cotton for nematode control in a field infested with root-knot and soybean cyst nematodes. DB Weaver, R Rodríguez-Kábana, and EL Carden A rapid screening method for resistance to nematodes and soilborne pathogens using alginate films. N Kokalis-Burelle, N Martínez-Ochoa, DB Weaver, and R Rodríguez-Kábana Progress of a project to identify differential cultivars and races of Cercospora sojina. DV Phillips and HR Boerma Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers. Text, references, figures, and cables are reproduced as they were submitted by the authors. The opinions exposed by the participants at this conference are their own and do not necessarily represent the views of the Southern Soybean Disease Workers. Mention of trademark, or propriety products in this Proceedings does not constitute a guarantee, warranty, or endorsement of that produce by the Southern Soybean Disease Workers

Proceedings of the 23rd Annual Meeting, Southern Soybean Disease Workers (March 24-25, 1996, Biloxi, Mississippi)

Contents Business session Soybean Disease Loss Estimate for the Southern United States during 1995. JA Wrather Treasurer report. GG Hammes SSDW Committee Chairmen for 1995-1996 Graduate student papers Effects of Bacteria Associated with Heterodera glycines in Soybean Fields of Arkansas. TK Field, RD Riggs, and TL Hart Influence of Soybean Pest Complexes on Maturation of Soybean Looper, Pseudoplusia includens. CH Carter, JS Russin, EC McGawley, DJ Boethel, and JL Griffin Contributed papers Resistance to Cyst Nematode in PI 437654 and Hartwig Soybeans. SC Ananad Rotation with Soybean Cultivar Hartwig and Nonhost Crops for Management of the Soybean Cyst Nematode. SR Koenning and KR Barker Relationship of Yield to the Development of Sudden Death Syndrome. JC Rupe Further Evaluation of Date of Planting Effects on Severity of Soybean Stem Canker. AY Chambers Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by the authors. The opinions exposed by the participants at this conference are their own and do not necessarily represent the views of the Southem Soybean Disease Workers. Mention of trademark or propriety products in this proceedings does not constitute a guarantee, warranty, or endorsement or that product by the Southern Soybean Disease Workers

Diversity-Oriented Synthesis Yields a Novel Lead for the Treatment of Malaria

Here, we describe the discovery of a novel antimalarial agent using phenotypic screening of Plasmodium falciparum asexual blood-stage parasites. Screening a novel compound collection created using diversity-oriented synthesis (DOS) led to the initial hit. Structure–activity relationships guided the synthesis of compounds having improved potency and water solubility, yielding a subnanomolar inhibitor of parasite asexual blood-stage growth. Optimized compound 27 has an excellent off-target activity profile in erythrocyte lysis and HepG2 assays and is stable in human plasma. This compound is available via the molecular libraries probe production centers network (MLPCN) and is designated ML238.Chemistry and Chemical Biolog

Metal Ion Dependence of Recombinant Escherichia coli Allantoinase

Allantoinase is a suspected dinuclear metalloenzyme that catalyzes the hydrolytic cleavage of the five-member ring of allantoin (5-ureidohydantoin) to form allantoic acid. Recombinant Escherichia coli allantoinase purified from overproducing cultures amended with 2.5 mM zinc, 1 mM cobalt, or 1 mM nickel ions was found to possess ∼1.4 Zn, 0.0 Co, 0.0 Ni, and 0.4 Fe; 0.1 Zn, 1.0 Co, 0.0 Ni, and 0.2 Fe; and 0.0 Zn, 0.0 Co, 0.6 Ni, and 0.1 Fe per subunit, respectively, whereas protein obtained from nonamended cultures contains near stoichiometric levels of iron. We conclude that allantoinase is incompletely activated in the recombinant cells, perhaps due to an insufficiency of a needed accessory protein. Enzyme isolated from nonsupplemented cultures possesses very low activity (k(cat) = 34.7 min(−1)) compared to the zinc-, cobalt-, and nickel-containing forms of allantoinase (k(cat) values of 5,000 and 28,200 min(−1) and 200 min(−1), respectively). These rates and corresponding K(m) values (17.0, 19.5, and 80 mM, respectively) are significantly greater than those that have been reported previously. Absorbance spectroscopy of the cobalt species reveals a band centered at 570 nm consistent with five-coordinate geometry. Dithiothreitol is a competitive inhibitor of the enzyme, with significant K(i) differences for the zinc and cobalt species (237 and 795 μM, respectively). Circular dichroism spectroscopy revealed that the zinc enzyme utilizes only the S isomer of allantoin, whereas the cobalt allantoinase prefers the S isomer, but also hydrolyzes the R isomer at about 1/10 the rate. This is the first report for metal content of allantoinase from any source

Biosynthesis of Active Bacillus subtilis Urease in the Absence of Known Urease Accessory Proteins

Bacillus subtilis contains urease structural genes but lacks the accessory genes typically required for GTP-dependent incorporation of nickel. Nevertheless, B. subtilis was shown to possess a functional urease, and the recombinant enzyme conferred low levels of nickel-dependent activity to Escherichia coli. Additional investigations of the system lead to the suggestion that B. subtilis may use unidentified accessory proteins for in vivo urease activation

Purification and Properties of the Klebsiella aerogenes UreE Metal-Binding Domain, a Functional Metallochaperone of Urease

Klebsiella aerogenes UreE, a metallochaperone that delivers nickel ions during urease activation, consists of distinct “peptide-binding” and “metal-binding” domains and a His-rich C terminus. Deletion analyses revealed that the metal-binding domain alone is sufficient to facilitate urease activation. This domain was purified and shown to exhibit metal-binding properties similar to those of UreE lacking only the His-rich tail