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High-throughput methods for the preparation of nonmevalonate terpene biosynthesis enzymes, which can be effectively used as antiinfective drugs, are described. Enzyme-assisted methods for the preparation of the required substrates in multigram amounts, with or without (13.Super)C labels in various positions that enable monitoring of enzyme reaction by (13.Super)C NMR, are presented.

The prevalence and antimicrobial resistance of Campylobacter isolates from both conventionally raised and organically raised broilers and turkeys are determined. The analysis has revealed the effect of conventional and organic poultry production practices on antimicrobial resistance of Campylobacter on poultry farms.

An observation about SigB that contributes positively to Listeria monocytogenes tolerance of the bacteriocins nisin and lacticin 3147 and of the antibiotics ampicillin and penicillin G. is presented. The results showed that SigB might contribute to the survival of Listeria monocytogenes both in the food-processing environment and in vivo during infection which might represent an attractive target for the development of new control and treatment strategies for this important pathogen.

A three-dimensional computer model of bio-film dynamics was developed as a tool for investigating mechanisms of protection from antimicrobial agents in bio-films. The differences between the protective mechanisms predicted in these simulations could guide the design of experiments to discriminate antimicrobial tolerance mechanisms in biofilms.

Byline: L. A. Smit (1), N. Haagsma (1), A. Ruiter (1) Keywords: Key wordsaSulphadimidine; Fermented sausage; Carbon-14-labelling; Rat; Bound residues Abstract: aSulphadimidine (SDM), a drug frequently administered to pigs, is partially converted into other compounds by processing meat to produce raw, fermented sausage. With the aid of 14.sup.C-labelled SDM, evidence was obtained that part of the radioactive matter was covalently bound to the matrix. Part of these bound residues could be released in vitro by 4M HCl at 21aadegC or by 0.024M HCl at 37aadegC. Female rats were also able to release bound SDM residues and to excrete these in their urine, in amounts approaching those obtained by treatment with 4M HCl. Both the parent compound and its main metabolite, N .sup.4-acetyl-SDM, were observed in the urine of rats. Author Affiliation: (1) Department of the Science of Food of Animal Origin, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.175, 3508 TD Utrecht, The Netherlands, NL Article note: Received: 29 December 1997 / Revised version: 20 February 1998

Byline: Jan RA-zicka (1), KateAina Velclova (1), Rahula Janis (1), JiAi Krejci (1) Keywords: Monoacylglycerols; Antimicrobial activity; Bacteria; Fungi; Yeasts Abstract: This study was aimed at assessing the effects exhibited by two types of monoacylglycerols (monocaprin and monolaurin, prepared by reactions of glycidol with the corresponding fatty acids) against important species of bacteria, filamentous fungi and yeast-like organisms. Results of determined minimal inhibitory concentrations (MICs) showed that monocaprin at concentrations of 100--250 mg/l is able to stop completely the growth of all Gram-positive bacteria and yeasts tested, and at concentrations of 100--400 mg/l, the growth of most filamentous fungi. On the other hand, some Gram-negative bacteria and also the fungus Mucor racemosus proved to be resistant to monocaprin. The antimicrobial spectrum of monolaurin was clearly narrower, and almost exclusively involved Gram-positive bacterial species, with levels of MICs from 20 to 200 mg/l. Author Affiliation: (1) Faculty of Technology, Tomas Bata University in Zlin, T.G.M. 275, 762 72, Zlin, Czech Republic Article History: Received Date: 26/05/2003 Online Date: 14/08/2003

Cloning, sequencing, and heterologous expression of the cyclothiazomycin biosynthetic gene cluster from Streptomyces hygroscopicus 10-22 is reported. The rigorous bioinformatics analysis based on heterologous expression of cyclothiazomycin led to an ideal biosynthetic model to better understand the biosynthesis of thiopeptides.

A study was conducted to examine the metabolic activity like oxygen consumption and acid formation and viability and the effect of antimicrobial chlorhexidine (CHX) treatment on the physiology of the dental biofilms during exposure to sucrose. The CHX exposure was observed to reduce the metabolic activity and microbial viability at the biofilm surface and drove metabolic activity deeper into the biofilm.

The various effects of the linear cationic antimicrobial peptide structures on the inhibition of the planktonic growth and biofilm formation in Escherichia coli are discussed. The hexameric, as well as the octameric peptides are shown to be the best inhibitors of the discussed growth.

The hyperthermophilic archaeon Pyrococcus furiosus was used to demonstrate the role of nitric oxide in Roussin's black salt (RBS) toxicity and the mechanism which involves membrane disruption leading to cell lysis. The results proposed RBS to be a new class of inorganic antimicrobial agent that also have potential use as an inert cell-lysing agent.

The development of a concise route for the preparation of new tetra-orthogonally protected (2S,6R)-lanthionines is described. The new orthogonally protected lanthionines could be used to study the lantibiotic family of antimicrobial peptides.

The combined lactic acid, monolaurin, and nisin effects on time-to-detection extension are greater than any single or paired combination effect that demonstrates a synergistic interaction among the antimicrobials. The results showed that lactic acid-enhanced monolaurin C12:0 absorption into the cell membrane increased membrane fluidity resulting in increased nisin activity.

A biosynthetic study on spiro-mamakone A, a potently cytotoxic and antimicrobial compound from an endophytic fungus isolated from the New Zealand native tree Knightia excelsa is reported. The biosynthesis proceeds via an unprecedented symmetric enedione with the two halves of the molecule formed from two separate pentaketide units connected by oxidative coupling and have confirmed the origin of polyketide to the spirobisnaphthalene class of compounds.

A method is described for converting tert-butyl benzoates or tert-butyl 1-naphthoates into derivatives having an alkyl or substituted alkyl group. The method can be applied to the synthesis of the antimicrobial fungal metabolite culpin.