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Digging with Experimental Pick and Computational Shovel: a New Addition to the Histidine Kinase Superfamily. Igor B. Zhulin, 2004. Metabolism of Dichloromethylcatechols as Central Intermediates in the Degradation of Dichlorotoluenes by Ralstonia sp . Strain PS12. Katrin Pollmann, 2002.Ralstonia sp . strain PS12 is able to use 2,4-, 2,5-, and 3,4-dichlorotoluene as growth substrates . Dichloromethylcatechols are central intermediates that are formed by TecA tetrachlorobenzene dioxygenase-mediated activation at two adjacent unsubstituted carbon atoms followed by TecB chlorobenzene dihydrodiol dehydrogenase-catalyzed rearomatization and then are channeled into a chlorocatechol ortho cleavage pathway involving a chlorocatechol 1,2-dioxygenase, chloromuconate cycloisomerase, and dienelactone hydrolase . However, completely different metabolic routes were observed for the three dichloromethylcatechols analyzed . Whereas 3,4-dichloro-6-methylcatechol is quantitatively transformed into one dienelactone (5-chloro-2-methyldienelactone) and thus is degraded via a linear pathway, 3,5-dichloro-2-methylmuconate formed from 4,6-dichloro-3-methylcatechol is subject to both 1,4- and 3,6-cycloisomerization and thus is degraded via a branched metabolic route . 3,6-Dichloro-4-methylcatechol, on the first view, is transformed predominantly into one (2-chloro-3-methyl-trans-) dienelactone . In situ 1H nuclear magnetic resonance analysis revealed the intermediate formation of 2,5-dichloro-4-methylmuconolactone, showing that both 1,4- and 3,6-cycloisomerization occur with this muconate and indicating a degradation of the muconolactone via a reversible cycloisomerization reaction and the dienelactone-forming branch of the pathway . Diastereomeric mixtures of two dichloromethylmuconolactones were prepared chemically to proof such a hypothesis . Chloromuconate cycloisomerase transformed 3,5-dichloro-2-methylmuconolactone into a mixture of 2-chloro-5-methyl-cis- and 3-chloro-2-methyldienelactone, affording evidence for a metabolic route of 3,5-dichloro-2-methylmuconolactone via 3,5-dichloro-2-methylmuconate into 2-chloro-5-methyl-cis-dienelactone . 2,5-Dichloro-3-methylmuconolactone was transformed nearly exclusively into 2-chloro-3-methyl-trans-dienelactone . Identification and Tracing of Bifidobacterium Species by Use of Enterobacterial Repetitive Intergenic Consensus Sequences. Marco Ventura, 2003.Eighty-nine Bifidobacterium strains from 26 species were identified and classified to the species level with an enterobacterial repetitive intergenic consensus (ERIC)-PCR approach . We demonstrated that ERIC-PCR is useful for a phylogenetic and taxonomical analysis but as well as for a species composition analysis of mixed bifidobacterial cultures isolated from dairy products and other environments .
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