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At least 829 records · Page 46Linked to original sources
PubMedDate not supplied

Diagnosis of swine dysentery: spirochaetes which may be confused with Treponema hyodysenteriae.

Spirochaetes, designated PWS, microscopically resembling Treponema hyodysenteriae, were isolated from the colon contents of pigs with post-weaning scours from three herds, which on clinical and epidemiological grounds were thought to be free from swine dysentery. One of the isolates was fed to pigs experimentally but no evidence of disease was noted. Their cultural characteristics differed from those of T hyodysenteriae but they were similar to those of a non-pathogenic spirachaete (4/71) which had been isolated previously from the laboratory's dysentery-free herd. Smears prepared from cultures of the PWS spirochaete, 4/71 and two virulent and one avirulent strain of T hyodysenteriae were all positive to a fluorescent antibody test which was in use as an aid to the diagnosis of swine dysentery in the United Kingdom.

Animals↗
PubMed1981

Use of fluorescence microscopy for monitoring periodontal disease state.

Samples of subgingival plaque from patients with periodontal disease and control subjects were stained with the Fluoretec Fluorescent test kits (Pfizer Inc., New York) developed for the rapid detection of members of the Bacteroides fragilis and B. melaninogenicus groups of anaerobes. The same fluorescent fields were also examined by dark-field microscopy for the total count of bacteria. Bacteroides fragilis and B. melaninogenicus were found in plaque samples of healthy subjects and periodontally diseased patients with no significant difference in percent of total flora. Oral spirochetes also fluoresced with the antisera used. Samples from healthy sites showed virtually no spirochetes; spirochetes were present in diseased sites. Tests with other antisera also showed that fluorescein-labelled antibodies can be adsorbed nonspecifically to the surface of spirochetes. Such a phenomenon can be used to monitor an individual's periodontal disease state.

Bacteroides↗
PubMed2002

Genetics of motility and chemotaxis of a fascinating group of bacteria: the spirochetes.

Spirochetes are a medically important and ecologically significant group of motile bacteria with a distinct morphology. Outermost is a membrane sheath, and within this sheath is the protoplasmic cell cylinder and subterminally attached periplasmic flagella. Here we address specific and unique aspects of their motility and chemotaxis. For spirochetes, translational motility requires asymmetrical rotation of the two internally located flagellar bundles. Consequently, they have swimming modalities that are more complex than the well-studied paradigms. In addition, coordinated flagellar rotation likely involves an efficient and novel signaling mechanism. This signal would be transmitted over the length of the cell, which in some cases is over 100-fold greater than the cell diameter. Finally, many spirochetes, including Treponema, Borrelia, and Leptospira, are highly invasive pathogens. Motility is likely to play a major role in the disease process. This review summarizes the progress in the genetics of motility and chemotaxis of spirochetes, and points to new directions for future experimentation.

Chemotaxis↗
PubMed1973

Flexibacteria.

Explore the source record for details and available documents.

Bacteria↗
PubMed2006

The flagellar cytoskeleton of the spirochetes.

The recent discoveries of prokaryotic homologs of all three major eukaryotic cytoskeletal proteins (actin, tubulin, intermediate filaments) have spurred a resurgence of activity in the field of bacterial morphology. In spirochetes, however, it has long been known that the flagellar filaments act as a cytoskeletal protein structure, contributing to their shape and conferring motility on this unique phylum of bacteria. Therefore, revisiting the spirochete cytoskeleton may lead to new paradigms for exploring general features of prokaryotic morphology. This review discusses the role that the periplasmic flagella in spirochetes play in maintaining shape and producing motility. We focus on four species of spirochetes: Borrelia burgdorferi, Treponema denticola, Treponema phagedenis and Leptonema (formerly Leptospira) illini. In spirochetes, the flagella reside in the periplasmic space. Rotation of the flagella in the above species by a flagellar motor induces changes in the cell morphology that drives motility. Mutants that do not produce flagella have a markedly different shape than wild-type cells.

Borrelia burgdorferi↗
PubMed1997

Structural analyses of plaque and caries in relation to the morphology of the groove-fossa system on erupting mandibular third molars.

Using 22 erupting human third mandibular molars, this study investigated: (1) the relationship between the morphology of the interlobal groove and the histological features of caries, (2) the ultrastructural features of the interlobal groove contents, and (3) whether the morphology of interlobal grooves influences the viability of the microorganisms. Posteruption time was classified as (1) < 3 months (7 teeth), (2) 3-12 months (8 teeth) and (3) > 12 months but < 18 months (7 teeth). The teeth were pre- and postfixed, and buccolingual sections were prepared. The mesial/distal interlobal groove on 116 sections was classified as fissure-like or groove-like. All sections were embedded and ground, and microradiographs were made. The interlobal groove contents were analyzed on two sections from each tooth, one with a fissure-like and one with a groove-like morphology, giving a total of 44 sections. Eighteen teeth (82%) had evidence of caries. Severity of caries was associated with length of posteruption time. 'Fissures' were not more prone to caries than 'grooves'. In about 70% of the 'fissures' caries had penetrated deepest at the entrance rather than in the deeper parts. LM and TEM examinations from 1 tooth disclosed erythrocytes, enamel organ cells and pioneers of microorganisms in the interlobal grooves. All other interlobal grooves were occupied by microorganisms, mainly gram-positive coccoids and small rods. Viable microorganisms were seen at the entrance as well as at the bottom part of the 'grooves'. In 'fissures' viable microorganisms were primarily observed at the entrance, while in deeper parts the microorganisms were less viable or dead. A moderate association was observed between the viability of the microorganisms and differences in the depths of caries penetration in the fissures. Thus, the internal morphology of the interlobal grooves influenced the conditions for bacterial growth and this determined the location for caries progression within the groove-fossa system.

Adolescent↗