Studies on the rod-coccus life cycle of Rhodococcus equi.
Abstract: In the present study all 19 Rhodococcus equi cultures isolated from horses and 19 of 22 R. equi cultures isolated from human patients displayed a rod-coccus life cycle after cultivation under defined growth conditions. A bacillary growth could be observed after cultivation of the bacteria in fluid media for 4 h at 37 degrees C, a coccoid morphology after cultivation of the bacteria for 24 h either on sheep blood agar plates or in fluid media. The different morphological features did not significantly influence the typability of the bacteria or the expression of surface proteins including 15-17 kDa virulence proteins. Studies on further surface characteristics revealed a relation between haemagglutinating properties, the surface hydrophobicity and adherence properties of the bacteria to HeLa cells. These properties seemed to be influenced by the cultivation conditions but not by the different morphological forms of the bacteria. A haemagglutination reaction, a hydrophobic surface and an enhanced adherence to HeLa cells could be observed with coccoid bacteria after cultivation in fluid media for 24 h at 37 degrees C but not with coccoid bacteria harvested from sheep blood agar plates or with bacillary bacteria after 4 h growth in fluid media. This difference might possibly be caused by the degree of encapsulation of the bacteria after various cultivation conditions and a subsequent masking effect of the hydrophilic polysaccharide capsule of R. equi.
Publication Date: 1997-07-01 PubMed ID: 9270351DOI: 10.1111/j.1439-0450.1997.tb00975.xGoogle Scholar: Lookup
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- Journal Article
Summary
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This research examines the life cycle of Rhodococcus equi, a bacterium associated with lung infections in horses and immunocompromised humans. The study reveals that the bacterium’s shape, either rod-shaped or spherical, doesn’t significantly influence its traits or virulence, but how it’s cultured can affect adherence properties and surface features.
Research Overview
- Rhodococcus equi, typically found in horses and humans, was subject to a series of cultures under specific growth conditions. The study found, in these precise conditions, that the bacterium demonstrated a life cycle from rod-shaped (bacillary) to spherical (coccoid) formations.
- Regardless of the shape, the bacteria exhibited similar typability (the ability to classify or characterize them), and the same expression of surface proteins, including proteins associated with virulence.
Morphology Versus Cultivation Conditions
- The research suggests that while the bacterium’s shape (morphology) does not influence the expression of its surface characteristics, the way it’s cultivated can.
- It was noted that certain properties like haemagglutinating activities (ability to cause red blood cells to clump together), surface hydrophobicity (a measure of the degree to which the bacteria repel water), and adherence to HeLa cells (a type of human cell line often used in research) seemed to be influenced by the cultivation conditions rather than the bacteria’s form.
Ideal Cultivation Conditions for Observation
- Spherical bacteria cultivated in fluid media for 24 hours at 37 degrees Celsius showed haemagglutination, hydrophobicity, and enhanced adherence to HeLa cells.
- On the contrary, these traits were not observed in spherical bacteria harvested from sheep blood agar plates or rod-shaped bacteria after 4 hours of growth in fluid media.
Implications of Encapsulation
- The research supposes that differences observed could be due to varying degrees of encapsulation, and the resulting masking effect of the bacteria after different cultivation conditions.
- Encapsulation involves the bacterium being surrounded by a protective layer, in this case, a hydrophilic (attracted to water) polysaccharide capsule, which may mask or alter certain observable characteristics of R. equi.
Cite This Article
APA
Fuhrmann C, Soedarmanto I, Lämmler C.
(1997).
Studies on the rod-coccus life cycle of Rhodococcus equi.
Zentralbl Veterinarmed B, 44(5), 287-294.
https://doi.org/10.1111/j.1439-0450.1997.tb00975.x Publication
Researcher Affiliations
- Institut für Bakteriologie und Immunologie, Justus-Liebig-Universität Giessen, Germany.
MeSH Terms
- AIDS-Related Opportunistic Infections / microbiology
- Actinomycetales Infections / epidemiology
- Actinomycetales Infections / microbiology
- Actinomycetales Infections / veterinary
- Animals
- Antibodies, Bacterial / analysis
- Bacterial Adhesion / physiology
- Bacterial Capsules / physiology
- Bacterial Outer Membrane Proteins / analysis
- Blotting, Western / veterinary
- Culture Media
- Electrophoresis, Polyacrylamide Gel / veterinary
- HeLa Cells
- Hemagglutination Tests / veterinary
- Horse Diseases / microbiology
- Horses
- Humans
- Incidence
- Rhodococcus equi / chemistry
- Rhodococcus equi / growth & development
- Rhodococcus equi / physiology
- Surface Properties
- Temperature
Citations
This article has been cited 5 times.- Herschend J, Raghupathi PK, Røder HL, Sørensen SJ, Burmølle M. Genome Sequence of Arthrobacter antarcticus Strain W2, Isolated from a Slaughterhouse. Genome Announc 2016 Mar 31;4(2).
- Be'er A, Florin EL, Fisher CR, Swinney HL, Payne SM. Surviving bacterial sibling rivalry: inducible and reversible phenotypic switching in Paenibacillus dendritiformis. mBio 2011;2(3):e00069-11.
- Fiuza M, Letek M, Leiba J, Villadangos AF, Vaquera J, Zanella-Cléon I, Mateos LM, Molle V, Gil JA. Phosphorylation of a novel cytoskeletal protein (RsmP) regulates rod-shaped morphology in Corynebacterium glutamicum. J Biol Chem 2010 Sep 17;285(38):29387-97.
- Young KD. The selective value of bacterial shape. Microbiol Mol Biol Rev 2006 Sep;70(3):660-703.
- Lührmann A, Mauder N, Sydor T, Fernandez-Mora E, Schulze-Luehrmann J, Takai S, Haas A. Necrotic death of Rhodococcus equi-infected macrophages is regulated by virulence-associated plasmids. Infect Immun 2004 Feb;72(2):853-62.
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