Some Features of the Fine Structure and Chemical Composition of Rhizobium trifolii

Vincent, J. M.; Humphrey, Beverley A.; North, Robert J.

doi:10.1099/00221287-29-3-551

Cited by 31 publications

(17 citation statements)

References 15 publications

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“…Only in preparations from P. diminuta was there evidence from electron micrographs of significant contamination of the walls by cytoplasmic or other materials. The preparations from P. diminuta contained a small amount of material similar to that found to contaminate wall preparations from Rhizobium trifolii (Vincent, Humphrey & North, 1962). The possibility that this material was P-hydroxybutyrate polymer was borne out by subsequent studies on lipids extracted from the preparations.…”

Section: General Observationsmentioning

confidence: 99%

Studies on the Cell Walls of Pseudomonas Species Resistant to Ethylenediaminetetra-acetic Acid

Wilkinson

1968

Journal of General Microbiology

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S U M M A R YCell walls were prepared from various species of the genus Pseudomonas which are resistant to ethylenediaminetetra-acetic acid (EDTA). The cell walls were analysed and comparisons made with the walls of EDTA-sensitive pseudomonads. The walls had none of the structural features which appeared to characterize EDTA-sensitive pseudomonads. Lipopolysaccharide was not extracted from the walls of resistant organisms by EDTA at pH 9-2. The wall of P . iodinum contained almost no lipid or protein but consisted mainly of glycosaminopeptide and material which resembled a teichoic acid. It is proposed that this organism be removed from the genus Pseudomonas. The walls of P. diminuta, P. maltophilia, P. pavonacea and P. rubescens had compositions broadly characteristic of Gram-negative bacteria. The four species are not obviously related. Glycolipids were present in the walls of P. diminuta, P. maltophilia and P. rubescens. An ornithine-containing lipid was isolated from P. rubescens and partly characterized. A small amount of this lipid was also present in P. maltophilia. The wall of P. maltophilia was distinctive in its wide range of monosaccharide components, including an unidentified neutral sugar of high mobility on paper chromatograms. INTRODUCTIONEthylenediaminetetra-acetic acid (EDTA) has a toxic effect on Pseudomonas aeruginosa (MacGregor & Elliker, 1958; Gray & Wilkinson, 1965a;Eagon & Carson, 1965;Wilkinson, 1967), apparently the result of a lytic action by it on the cell wall of the organism (Gray & Wilkinson, 1965a, b ;Eagon & Carson, 1965). A correlation has been found between bactericidal activity and chelate stability constants for polyaminocarboxylic acids related to EDTA, which indicated that chelation was involved in the toxic action of these compounds (Gray & Wilkinson, 19654. The structural importance of multivalent metal cations in the wall of P. aeruginosa has been confirmed (Eagon & Carson, 1965;Asbell & Eagon, 1966a, b). Treatmh of the bacteria with EDTA caused these cations to become soluble (Eagon & Carson, 1965) and also of the lipopolysaccharide component of the cell wall (Gray & Wilkinson, 1965 b). Although EDTA has been found to extract lipopolysaccharide from Escherichia coli, the bacteria remained viable under the conditions used (Leive, 1965). Except when used in conjunction with organic cations (Wolin, 1966;Goldschmidt & Wyss, 1967;Voss, 1967), EDTA does not seem to be highly toxic for Gram-negative bacteria other than pseudomonads (Gray & Wilkinson, 1965 a;Wilkinson, 1967). This hypersensitivity to EDTA might prove to be a useful characteristic in the taxonomy of the pseudomonads (Shively & Hartsell, 1964;Wilkinson, 1967 S . G. W I L K I N S O NIn a survey of various pseudomonads (Wilkinson, 1967), only strains of the following species were found to be resistant to EDTA: Pseudomonas diminuta, P. geniculata, P. iodinum, P. maltophilia, P. pavonacea, P. rubescens. The inclusion of these organisms in the genus Pseudomonas has been considered doubtful by other workers who used di...

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Section: General Observationsmentioning

confidence: 99%

Studies on the Cell Walls of Pseudomonas Species Resistant to Ethylenediaminetetra-acetic Acid

Wilkinson

1968

Journal of General Microbiology

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“…The amount of PHB accumulated by rhizobia has been found to be dependent on the species and availability of carbon in the medium (32,33). Consequently, the decrease of PHB in cells grown in crude peat extract suggests that the available carbon may be limited in the extract or perhaps metabolic energy is being redirected elsewhere as an adaptive response.…”

Section: Discussionmentioning

confidence: 99%

Physiological Changes in Rhizobia after Growth in Peat Extract May Be Related to Improved Desiccation Tolerance

Casteriano

Wilkes

Deaker

2013

Appl Environ Microbiol

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Improved survival of peat-cultured rhizobia compared to survival of liquid-cultured cells has been attributed to cellular adaptations during solid-state fermentation in moist peat. We have observed improved desiccation tolerance of Rhizobium leguminosarum bv. trifolii TA1 and Bradyrhizobium japonicum CB1809 after aerobic growth in water extracts of peat. Survival of TA1 grown in crude peat extract was 18-fold greater than that of cells grown in a defined liquid medium but was diminished when cells were grown in different-sized colloidal fractions of peat extract. Survival of CB1809 was generally better when grown in crude peat extract than in the control but was not statistically significant (P > 0.05) and was strongly dependent on peat extract concentration. Accumulation of intracellular trehalose by both TA1 and CB1809 was higher after growth in peat extract than in the defined medium control. Cells grown in water extracts of peat exhibit morphological changes similar to those observed after growth in moist peat. Electron microscopy revealed thickened plasma membranes, with an electron-dense material occupying the periplasmic space in both TA1 and CB1809. Growth in peat extract also resulted in changes to polypeptide expression in both strains, and peptide analysis by liquid chromatography-mass spectrometry indicated increased expression of stress response proteins. Our results suggest that increased capacity for desiccation tolerance in rhizobia is multifactorial, involving the accumulation of trehalose together with increased expression of proteins involved in protection of the cell envelope, repair of DNA damage, oxidative stress responses, and maintenance of stability and integrity of proteins.

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“…The amount of PHB accumulated by rhizobia has been found to be dependent on the species and availability of carbon in the media (Vincent et al, 1962;BenRebah et al, 2009). Consequently, the decrease of PHB in cells grown in peat extract suggests that the available carbon may be limited in the extract or perhaps metabolic energy is being re-directed elsewhere as an adaptive response.…”

Section: Discussionmentioning

confidence: 99%

“…6) comprises of an outer membrane covalently bonded to a thin peptidoglycan layer, and an inner or plasma membrane encapsulating the cytoplasm. The space separating these two membranes is referred to as the periplasm or periplasmic space (Vincent et al, 1962;de Maagd & Lugtenberg, 1986;Ruiz et al, 2009). Electron microscopy has often been used to study the morphology of bacterial cells and cell compartments.…”

Section: Discussionmentioning

confidence: 99%

The Physiological Mechanisms of Desiccation Tolerance in Rhizobia

Casteriano¹,

Wilkes²,

Deaker³

2015

Biological Nitrogen Fixation

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Some Features of the Fine Structure and Chemical Composition of Rhizobium trifolii

Cited by 31 publications

References 15 publications

Studies on the Cell Walls of Pseudomonas Species Resistant to Ethylenediaminetetra-acetic Acid

Studies on the Cell Walls of Pseudomonas Species Resistant to Ethylenediaminetetra-acetic Acid

Physiological Changes in Rhizobia after Growth in Peat Extract May Be Related to Improved Desiccation Tolerance

The Physiological Mechanisms of Desiccation Tolerance in Rhizobia

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