Ambulacraria, comprising Hemichordata and Echinodermata 1, is closely related to Chordata, making it integral to understanding chordate origins and polarizing chordate molecular and morphological ...characters 2-4. Unfortunately, relationships within Hemichordata and Echinodermata have remained unresolved 1, 5-10, compromising our ability to extrapolate findings from the most closely related molecular and developmental models outside of Chordata (e.g., the acorn worms Saccoglossus kowalevskii and Ptychodera flava and the sea urchin Strongylocentrotus purpuratus). To resolve long-standing phylogenetic issues within Ambulacraria, we sequenced transcriptomes for 14 hemichordates as well as 8 echinoderms and complemented these with existing data for a total of 33 ambulacrarian operational taxonomic units (OTUs). Examination of leaf stability values revealed rhabdopleurid pterobranchs and the enteropneust Stereobalanus canadensis were unstable in placement; therefore, analyses were also run without these taxa. Analyses of 185 genes resulted in reciprocal monophyly of Enteropneusta and Pterobranchia, placed the deep-sea family Torquaratoridae within Ptychoderidae, and confirmed the position of ophiuroid brittle stars as sister to asteroid sea stars (the Asterozoa hypothesis). These results are consistent with earlier perspectives concerning pleslomorphles of Ambulacraria, including pharyngeal gill slits, a single axocoel, and paired hydrocoels and somatocoels 1, 4, 11. The resolved ambulacrarian phylogeny will help clarify the early evolution of chordate characteristics and has implications for our understanding of major fossil groups, including graptolites and somasteroideans.
Enterotoxigenic Clostridium perfringens was associated with diarrhea in a 4-yr-old female captive-bred red-footed tortoise (Geochelone carbonaria ). Diagnosis was based on bacterial culture, ...detection of C. perfringens enterotoxin in feces, and exclusion of commonly recognized pathogens. After treatment with metronidazole, normal feces were passed and C. perfringens enterotoxin was no longer detected in the feces. Although the role of C. perfringens cannot be determined definitively from this case, this pathogen should be considered in cases of diarrhea in tortoises and, perhaps, other reptiles.
The role of the inanimate environment, including the air, in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) infection is unclear; however, there are certain situations when ...evaluation of MRSA contamination of the environment is indicated. At this point, conventional culture methods are predominantly used, with molecular methods reserved for characterization of recovered isolates. A variety of methods are available for environmental sampling, and the objectives of sampling must be considered when choosing the appropriate technique.
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