Effects of Freeze-Drying and Sporulation on Microbial Variation

Servin-Massieu, Manuel

doi:10.1007/978-3-642-65123-6_5

Cited by 10 publications

(5 citation statements)

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“…Results of this study demonstrated that as the lyophilization time increased, the number of viable cells declined, and at the same time, more changes were observed on the cell surface. These data suggest that the rehydration of bacterial cells can introduce various types of variation, such as metabolic injury or genetic damage (27). In our previous studies (17) of changes of colony morphology in SSA, we showed that drying affects cells more than freezing does.…”

Section: Discussionmentioning

confidence: 61%

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Outermost-cell-surface changes in an encapsulated strain of Staphylococcus aureus after preservation by freeze-drying

Ohtomo

Yamada

Yoshida

1988

Appl Environ Microbiol

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The effects of drying time during freeze-drying on the outermost cell surface of an encapsulated strain of Staphylococcus aureus S-7 (Smith, diffuse) were investigated, with special attention paid to capsule and slime production. To quantify capsule and slime production, capsule antigen production and cellular characteristics such as growth type in serum-soft agar, cell volume index, and clumping factor reaction were examined. After freeze-drying the colonial morphology of strain S-7 was altered from a diffuse to a compact type in serum-soft agar. In accordance with these changes, the titer of the clumping factor reaction increased while the cell volume index, capsule and slime production, and capsule antigen production were markedly decreased in parallel with the period of freeze-drying. The ability of the strain to adhere to collagen, fibrinogen, and soybean lectin was also compared before and after freeze-drying. Fibrinogen levels slightly increased when 10% skim milk and 2% honey were used as cryoprotective agents and showed a remarkable increase when 0.05 M phosphate buffer was used as a control. Also, the ability of strain S-7 to adhere to soybean lectin declined, whereas no changes were observed for collagen under any conditions. Strain S-7 was phage nontypable before freeze-drying but the number of typable cells increased after freeze-drying; phage-typable cells reacted to phage 52 alone after 5 h of freeze-drying, but additional cells also proved to be phage typable to phage 42E after 10 h. Electron micrographs indicated that strain S-7, an encapsulated strain, was converted to an unencapsulated state after freeze-drying. Results of our study indicate that the freeze-drying process inhibits capsule and slime production in S. aureus, which consequently brings about changes in the outermost cell surface.

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Section: Discussionmentioning

confidence: 61%

“…In many studies the mechanisms of damage to frozen or freeze-dried cells, such as injury to cytoplasmic and outer membrane integrity (2,6,24,25), disruption of active transport and protein synthesis (8,9,30), damage to DNA (22,27,28,37), and disruption of cell morphology (5,10), have been reported.…”

Section: Discussionmentioning

confidence: 99%

Outermost-cell-surface changes in an encapsulated strain of Staphylococcus aureus after preservation by freeze-drying

Ohtomo

Yamada

Yoshida

1988

Appl Environ Microbiol

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“…The first head of the National Bacteriology Institute and the pioneer of microbiology in Mexico, Ángel Gaviño, had been trained by Roux and Duclaux at the Pasteur Institute, 23 while Joseph Girard, a French bacteriologist who interned at the Pasteur Institute, worked from 1906 to 1913 as the assistant director of the Laboratory of the National Bacteriology Institute in Mexico. 24 But that period also saw a great diversification of influences.…”

Section: Introductionmentioning

confidence: 99%

Vaccine production, national security anxieties and the unstable state in nineteenth- and twentieth-century Mexico

Carrillo¹

2017

The Politics of Vaccination

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“…Cultures of many microorganisms are maintained in a dry state (8). Many biologists consider that drying and rehydration cause little or no genetic damage, even though there is some evidence to the contrary (3,6,7,13,15,17). It was recently demonstrated that genetic changes are induced when Saccharomyces cerevisiae cells are dried in air with a relative humidity (RH) below 53%, so that the water content (grams of water per gram of dry material) of the cells is reduced to less than 12% (6).…”

mentioning

confidence: 99%