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Transformation of Verapamil by Cunninghamella blakesleeana. Lu Sun, 2004.A filamentous fungus, Cunninghamella blakesleeana AS 3.153, was used as a microbial model of mammalian metabolism to transform verapamil, a calcium channel antagonist . The metabolites of verapamil were separated and assayed by the liquid chromatography-ion trap mass spectrometry method . After 96 h of incubation, nearly 93% of the original drug was metabolized to 23 metabolites . Five major metabolites were isolated by semipreparative high-performance liquid chromatography and were identified by proton nuclear magnetic resonance and electrospray mass spectrometry . Other metabolites were characterized according to their chromatographic behavior and mass spectral data . The major metabolic pathways of verapamil transformation by the fungus were N dealkylation, O demethylation, and sulfate conjugation . The phase I metabolites of verapamil (introduction of a functional group) by C . blakesleeana paralleled those in mammals; therefore, C . blakesleeana could be a useful tool for generating the mammalian phase I metabolites of verapamil . Isolation of Novel Ultramicrobacteria Classified as Actinobacteria from Five Freshwater Habitats in Europe and Asia. Martin W. Hahn, 2003.We describe the first freshwater members of the class Actinobacteria that have been isolated . Nine ultramicro-size (<0.1 µm3) strains were isolated from five freshwater habitats in Europe and Asia . These habitats represent a broad spectrum of ecosystems, ranging from deep oligotrophic lakes to shallow hypertrophic lakes . Even when the isolated strains were grown in very rich media, the cell size was <0.1 µm3 and was indistinguishable from the cell sizes of bacteria belonging to the smaller size classes of natural lake bacterioplankton . Hybridization of the isolates with oligonucleotide probes and phylogenetic analysis of the 16S rRNA gene sequences of the isolated strains revealed that they are affiliated with the class Actinobacteria and the family Microbacteriaceae . The previously described species with the highest levels of sequence similarity are Clavibacter michiganensis and Rathayibacter tritici, two phytopathogens of terrestrial plants . The 16S rRNA gene sequences of the nine isolates examined are more closely related to cloned sequences from uncultured freshwater bacteria than to the sequences of any previously isolated bacteria . The nine ultramicrobacteria isolated form, together with several uncultured bacteria, a diverse phylogenetic cluster (Luna cluster) consisting exclusively of freshwater bacteria . Isolates obtained from lakes that are ecologically different and geographically separated by great distances possess identical 16S rRNA gene sequences but have clearly different ecophysiological and phenotypic traits . Predator-prey experiments demonstrated that at least one of the ultramicro-size isolates is protected against predation by the bacterivorous nanoflagellate Ochromonas sp . strain DS . Identification of Novel Cryptosporidium Genotypes from the Czech Republic. Una Ryan, 2003.Isolates of Cryptosporidium from the Czech Republic were characterized from a variety of different hosts using sequence and phylogenetic analysis of the 18S ribosomal DNA and the heat-shock (HSP-70) gene . Analysis expanded the host range of accepted species and identified several novel genotypes, including horse, Eurasian woodcock, rabbit, and cervid genotypes .
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