Document Detail

Surface layers of Eubacterium yurii subsp. yurii and their possible role in test-tube brush formation and iron acquisition.
MedLine Citation:
PMID:  1753391     Owner:  NLM     Status:  MEDLINE    
Eubacterium yurii subsp. yurii is an anaerobic, gram-positive rod. On isolation E. yurii forms cellular arrangements resembling test-tube brushes (TTB). Although TTB decreased in size and number on repeated laboratory subculture in enriched media, media poor in available iron enhanced formation of these. Plasmids were not demonstrated, even after chloramphenicol enhancement. To characterise the nature and possible physiological roles of the structures of the TTB, they were examined by transmission electronmicroscopy (TEM) with thin-section, negative-staining, shadow-casting, freeze-etching and freeze-fracturing techniques, and by scanning electronmicroscopy (SEM). Previous studies by phase-contrast microscopy revealed an amorphous core, the size of which varied in direct proportion to the number of associated bacterial cells. Thin sections of the TTB showed a gram-positive cell wall with additional surface layers. Negative staining, shadow casting and freeze etching revealed a surface layer comprising subunits in tetragonal array (P4 symmetry). Shadow casting showed also that the outermost layer of the cells was composed of fibrillar structures closely associated with but distinct from, the tetragonal layer. The fibrils extended from the cell surface in clumps or strands. The presence of these fibrils was confirmed by the freeze-fracture technique and SEM. Chemical analysis of the core material of the TTB showed it to be low in carbohydrate (0.06%) and protein (0.2%). Energy-dispersive X-ray spectrometry showed that the core was composed mostly of iron.(ABSTRACT TRUNCATED AT 250 WORDS)
G N Krywolap; W Fischlschweiger; C L Dabirsiaghi; B S Margaret
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of medical microbiology     Volume:  35     ISSN:  0022-2615     ISO Abbreviation:  J. Med. Microbiol.     Publication Date:  1991 Dec 
Date Detail:
Created Date:  1992-01-28     Completed Date:  1992-01-28     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  0224131     Medline TA:  J Med Microbiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  338-44     Citation Subset:  IM    
Department of Microbiology, University of Maryland School of Dentistry, Baltimore 21201.
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MeSH Terms
Bacterial Adhesion*
Cell Wall / microbiology,  physiology,  ultrastructure*
Eubacterium / physiology,  ultrastructure*
Freeze Etching
Freeze Fracturing
Iron / metabolism*
Microscopy, Electron, Scanning
Structure-Activity Relationship
Reg. No./Substance:

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