Water Permeability of Bacterial Spores and the Concept of a Contractile Cortex

Lewis, John B.; Snell, Neva; Burr, Horace K.

doi:10.1126/science.132.3426.544

Cited by 135 publications

(76 citation statements)

References 5 publications

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“…This is a structure inside the spore coat and surrounding the central core. Lewis, Snell & Burr (1960) suggested that the core might have a low freewater content because it is squeezed dry by a contractile cortex. This presupposes that an early event in germination would be loss of strength of this structure, perhaps by lysis with release of hexosamine-containing peptides.…”

Section: Discussionmentioning

confidence: 99%

The Swelling of Bacterial Spores during Germination and Outgrowth

Hitchins

Gould

Hurst

1963

Journal of General Microbiology

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SUMMARYThe swelling of spores of Bacillus cereus and B . subtilis during germination and outgrowth was followed by measuring changes in packed cell volume (pcv) and by photomicrographic measurements of single organisms. Three stages of swelling were recognized : (1) germination swelling involving a rapid increase of about 20% in pcv as the spore germinated; (2) preemergence swelling of up to 100 yo increase in pcv before emergence from the spore coat; (3) elongation. Germination swelling was due mainly to an increase in the breadth of the spore. It occurred in the absence of oxygen and was not inhibited by nisin whereas pre-emergence swelling was oxygen-dependent and was inhibited by nisin. Post-emergence swelling occurred during elongation of the new vegetative form. The significance of these findings is discussed,

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Section: Discussionmentioning

confidence: 99%

The Swelling of Bacterial Spores during Germination and Outgrowth

Hitchins

Gould

Hurst

1963

Journal of General Microbiology

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“…The cortex PG is composed of glycan strands made of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), the latter of which may be modified to muramic ␦-lactam or whose side chain may be cleaved to a single L-alanine (2,39,46). These distinct modifications result in a loosely cross-linked cortex that helps maintain dehydration, promoting spore heat resistance and dormancy (22,38,45).…”

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confidence: 99%

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

Lambert

Popham

2008

J Bacteriol

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Bacillus anthracis spores, the infectious agents of anthrax, are notoriously difficult to remove from contaminated areas because they are resistant to many eradication methods. These resistance properties are due to the spore's dehydration and dormancy and to the multiple protective layers surrounding the spore core, one of which is the cortex. In order for B. anthracis spores to germinate and resume growth, the cortex peptidoglycan must be depolymerized. This study reports on analyses of sleL (yaaH), which encodes a cortex-lytic enzyme. The inactivation of sleL does not affect vegetative growth, spore viability, or the initial stages of germination, including dipicolinic acid release. However, mutant spores exhibit a slight delay in the loss of optical density compared to that of wild-type spores. Mutants also retain more diaminopimelic acid and N-acetylmuramic acid during germination than wild-type spores, suggesting that the cortex peptidoglycan is not being hydrolyzed as rapidly. This finding is supported by high-pressure liquid chromatography analysis of the peptidoglycan structure used to confirm that SleL acts as an N-acetylglucosaminidase. When sleL is inactivated, the cortex peptidoglycan is not depolymerized into small muropeptides but instead is retained within the spore as large fragments. In the absence of the sleL-encoded N-acetylglucosaminidase, other cortex-lytic enzymes break down the cortex peptidoglycan sufficiently to allow rapid germination and outgrowth.

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“…For example, POWELL and STRANGE (1) gave this result from the measurement of density and volume of spores, WALDHAM and HALVORSON (2) from isothermal adsorption curves for water vapor, and Ross and BILLIN X (3) from the measurement of refractive index of spores. In this connection, L Jwis, S' LL and BURR (4) proposed the hypothesis that the low water content of spores may result from the contraction of the spore cortex during the spore maturation.…”

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confidence: 99%

Physical Properties of Water in Spores of Bacillus Megaterium

Maeda

Fujita

Sugiura

et al. 1968

J. Gen. Appl. Microbiol.

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Several physical properties of spores of Bacillus megaterium, such as vapor pressure isotherm, complex dielectric constant, nuclear magnetic resonance absorption spectrum, as well as water sorption and desorption rates, were studied in comparison with those of vegetative cells of the same organism with respect to content and form of the cell water. Spores showed larger water content as compared with vegetative cells in the humidity range of less than 78% (R. H.) at 30°, while they showed smaller water content over more humid ranges up to 100% (R. H.). Spores showed a smaller dielectric loss at a microwave frequency of 10 Gc and a broader NMR absorption pattern than vegetative cells. These facts are discussed briefly in terms of molecular motion of the cell water in spores and vegetative cells. Dormant spores of bacteria have higher resistance to heating and chemical treatments than their vegetative forms. Various types of study have been made by a number of investigators on these characteristic features of spores. Studies on the content and form of water in spores are among others.However, different conclusions have been obtained by different investigators, and no satisfactory relation has yet been established between the high resistivity and the state of water molecules in spores.It has been reported by many workers that bacterial spores have lower water content than vegetative cells. For example, POWELL and STRANGE (1) gave this result from the measurement of density and volume of spores, WALDHAM and HALVORSON (2) from isothermal adsorption curves for water vapor, and Ross and BILLIN X (3) from the measurement of refractive index of spores. In this connection, L Jwis, S' LL and BURR (4) proposed the hypothesis that the low water content of spores may result from the contraction of the spore cortex during the spore maturation.On the other hand, H ~N Y and F zl °) V1AN (5, 6) noted that the difference in water content between spores and vegetative cells is not sufficiently great to explain the resistivity of spores. They concluded from their cry-217

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Water Permeability of Bacterial Spores and the Concept of a Contractile Cortex

Abstract: Assumption of a water-impermeable coat on bacterial spores is inconsistent with known permeabilities of organic materials. A low water content may arise through compressive contraction of the cortex during spore maturation.

Cited by 135 publications

References 5 publications

The Swelling of Bacterial Spores during Germination and Outgrowth

The Swelling of Bacterial Spores during Germination and Outgrowth

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

Physical Properties of Water in Spores of Bacillus Megaterium

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