Thermally Induced Ribonucleic Acid Degradation and Leakage of Substances from the Metabolic Pool in
            <i>Staphylococcus aureus</i>

Self Cite

SUMMAEY. Staphy~ococcus au~eue cells which had been heated at 60 or 60' were transferred to various growth media and intracellular ribonucleic acid (RNA), deoxyribonucleic acid (DNA) and amino acids were measured during the lag phase of growth. The duration of the lag phase depended on the temperature to which the cultures had been subjected, and was longest following storage at 60". RNA synthesis occurred almost immediately on placing treated cells in a growth medium, but at a slower rate than with unheated cells. Variation in the composition of the metabolic pool of heated cells occurred during the early lag phase and may be as a result of damage to the cytoplasmic membrane with resulting loss of permeability control.

Section: Resultssupporting

confidence: 69%

“…Ten ml samples were removed at intervals and RNA, DNA and amino acids were determined as previously described (Allwood & Russell, 1968). Growth was followed nephelometrically .…”

Section: Viable Countsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Growth and Metabolic Activities of Heat Treated Staphylococcus aureus

Allwood¹,

Russell²

1969

Self Cite

“…Previous workers have reported cytoplasmic membrane damage for a wide range of stress conditions including Allwood and Russell (1968), Strange andCox (1976), Rrennan et al (1986) and Ray (1993).…”

Section: Discussionmentioning

confidence: 95%

Spray drying as a method for preparing concentrated cultures of Lactobacillus bulgaricus

Teixeira

Castro

Kirby

1995

139

123

P. TEIXEIRA, H. CASTRO AND R. KIRBY. 1995. Spray drying and freeze drying as methods for concentration of Lactobacillus bulgaricus starter cultures were compared in terms of viability, lag phase until onset of pH decrease and total acid production. For the experimental conditions used, no significant differences were detected between the methods. The effect of spray drying on the cell membrane of Lactobacillus bulgaricus was studied. Five separate methods were used to study the theory that spray drying causes cell membrane damage; three relating to leakage of intracellular components from the cell into the surrounding environment (260 and 280 nm absorbing materials, potassium ions and proteins); and two relating to increased cell permeability (increased sensitivity to NaCl and increased permeability to o‐nitrophenyl‐β‐D‐galactopyranoside (ONPG). Partial loss of some cytoplasmic material from the damaged cells was observed. The dried cells also became sensitive to NaCl and permeable to ONPG. Heat shock increased the survival of exponential cells as compared to controls but did not result in normal levels found with unshocked stationary phase cells. Heat shock had no effect on stationary phase cells. Different rehydration methods and media were investigated: slow rehydration increased survival.

“…Wood (1956) proposed, from the scant evidence then available, that DNA was involved, but subsequent studies have shown that in Aerobacter aerogenes (Strange & Shon, 1964) and Xtaph. aureus (Allwood & Russell, 1968), there is no degradation of DNA a t temperatures a t which a marked lethal effect on the bacteria is observed. However, RNA is degraded a t these temperatures, and precedes leakage from the acid soluble nucleotide pool (Allwood & Russell, 1968).…”

Section: Discussionmentioning

confidence: 95%

Thermally Induced Changes in the Physical Properties of Staphylococcus aureus

Allwood

Russell

1969

Self Cite

When suspensions o f ~!?taphy~ococcu8 aureu8 were stored at different temperatures in water or M sucrose, an increase or decrease (depending on the temperature of storage and the nature of the environment) in O.D. and light scattering properties occurred. Such changes were related to changes in cell size. leakage of intracellular constituents from the cells and precipitation of cytoplasmic material. Electron micrographs of ultrathin sections of cells illustrated some of these changes. The results demonstrated that caution was necessary in the interpretation of changes in O.D. and light scattering properties of this organism.