Molecular and biochemical comparisons of Blastocystis isolates from animal and human hosts /
Blastocystis is a poorly understood extracellular, single celled, eukaryotic organism frequently found in the gastrointestinal tract of humans and other vertebrate and invertebrate hosts. Blastocystis hominis is the scientific name currently used for human isolates, and 9 other species names have b...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2001.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726104291&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Blastocystis is a poorly understood extracellular, single celled, eukaryotic organism frequently found in the gastrointestinal tract of humans and other vertebrate and invertebrate hosts. Blastocystis hominis is the scientific name currently used for human isolates, and 9 other species names have been proposed for isolates from animal hosts. Blastocystis was described as early as 1911 (Alexeieff), but progress in our knowledge has been limited due to lack of critical research, shortage of funding and failure to use reference strains for comparisons among published studies. The small subunit ribosomal RNA (ssu rRNA) gene from 24 Blastocystis isolates (14 animal and 10 human) from 9 host species was amplified by polymerase chain reaction, cloned and sequenced. Sequences were compared and phylogenetic analyses conducted including GenBank Blastocystis ssu rRNA gene sequences. Eight clades were identified and a similar topology was found by parsimony, maximum likelihood and distance analyses. Blastocystis isolate sequences were found to generally segregate into at least 2 major groups, animal or human. To determine if more than 1 ssu rRNA gene copy existed in Blastocystis isolates, 2 isolates (guinea pig and human) were compared by Southern blotting. Results suggest that the guinea pig Blastocystis isolate contains 1 ssu rRNA gene copy, whereas the human isolate may contain more than 1 gene copy. The internal transcribed spacers (ITS1 and ITS2), 5.8S and partial large subunit (lsu) rRNA genes were amplified, cloned and sequenced from 5 Blastocystis (1 guinea pig and 4 human) isolates. Data conclude that Blastocystis is a typical eukaryote. The animal Blastocystis isolate was clearly different when compared to the human isolates. Gel electrophoresis and Western blotting analysis revealed great heterogeneity in protein and antigenic profiles among 12 selected Blastocystis isolates (6 animal and 6 human). Western blotting results supported the ssu rRNA gene finding that the Blastocystis isolates could be designated into at least 2 groups, 1 animal and 1 human. Finally, the ssu rRNA gene, 5.8S and partial lsu rRNA gene sequences supported the classification of Blastocystis isolates as stramenopiles (Kingdom Chromista, subphylum Heterokonta), at least until strong evidence suggests otherwise. |
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| Item Description: | Vita. "Major Subject: Veterinary Microbiology". |
| Physical Description: | xii, 162 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 118-138). |