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Concentration and Assembly of the Division Ring Proteins FtsZ, FtsA, and ZipA during the Escherichia coli Cell Cycle. Sonsoles Rueda, 2003.The concentration of the cell division proteins FtsZ, FtsA, and ZipA and their assembly into a division ring during the Escherichia coli B/r K cell cycle have been measured in synchronous cultures obtained by the membrane elution technique . Immunostaining of the three proteins revealed no organized structure in newly born cells . In a culture with a doubling time of 49 min, assembly of the Z ring started around minute 25 and was detected first as a two-dot structure that became a sharp band before cell constriction . FtsA and ZipA localized into a division ring following the same pattern and time course as FtsZ . The concentration (amount relative to total mass) of the three proteins remained constant during one complete cell cycle, showing that assembly of a division ring is not driven by changes in the concentration of these proteins . Maintenance of the Z ring during the process of septation is a dynamic energy-dependent event, as evidenced by its disappearance in cells treated with sodium azide . Terbinafine Resistance Mediated by Salicylate 1-Monooxygenase in Aspergillus nidulans. Marcia A. S. Graminha, 2004.Resistance to antifungal agents is a recurring and growing problem among patients with systemic fungal infections . UV-induced Aspergillus nidulans mutants resistant to terbinafine have been identified, and we report here the characterization of one such gene . A sib-selected, 6.6-kb genomic DNA fragment encodes a salicylate 1-monooxygenase (salA), and a fatty acid synthase subunit (fasC) confers terbinafine resistance upon transformation of a sensitive strain . Subfragments carrying salA but not fasC confer terbinafine resistance . salA is present as a single-copy gene on chromosome VI and encodes a protein of 473 amino acids that is homologous to salicylate 1-monooxygenase, a well-characterized naphthalene-degrading enzyme in bacteria . salA transcript accumulation analysis showed terbinafine-dependent induction in the wild type and the UV-induced mutant Terb7, as well as overexpression in a strain containing the salA subgenomic DNA fragment, probably due to the multicopy effect caused by the transformation event . Additional naphthalene degradation enzyme-coding genes are present in fungal genomes, suggesting that resistance could follow degradation of the naphthalene ring contained in terbinafine .
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