On the Nature of the Heat Resistance of Thermophilic Bacteria

Ljunger, Claes

doi:10.1111/j.1399-3054.1970.tb06425.x

Cited by 33 publications

(20 citation statements)

References 19 publications

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“…Calcium was over three times more effective than equivalent concentration of Na+ in reducing K+ efflux from the bulb scale tissue (Table I). This is consistent with the general protective effect of Ca2" on many cellular processes during stress (5,8,10,12) and postulated role of Ca2+ on the maintenance of membrane integrity (9).…”

Section: Discussionsupporting

confidence: 70%

Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells

Arora¹,

Palta²

1986

Plant Physiol.

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Freezing injury, in onion bulb tissue, is known to cause enhanced K' efflux accompanied by a small but significant loss of Ca2" following incipient freezing injury and swelling of protoplasm during the postthaw secondary injury. The protoplasmic swelling of the cell is thought to be caused by the passive influx of extracellular K' into the cell followed by water uptake. Using outer epidermal layer of unfrozen onion bulb scales (Allium cepa L. cv Big Red), we were able to stimulate the irreversible freezing injury symptoms, by bathing epidermal cells in 50 millimolar KCI. These symptoms were prevented by adding 20 millimolar CaCI2 to the extracellular KCI solution. Our results provide evidence that loss of cellular Ca2' plays an important role in the initiation and the progression of freezing injury.

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Section: Discussionsupporting

confidence: 70%

Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells

Arora¹,

Palta²

1986

Plant Physiol.

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“…The Arrhenius plot in fig.4 indicates that the Thus calcium appears to be taken up by living calcium uptake rate increases with temperature, in cells at a rate which increases with temperature. In accordance with the higher demand for calcium at the light of earlier results [6,7] that calcium is needed for survival at high temperatures, we conclude that calcium is not just accumulated as a consequence of, but is indeed required for thermophilic growth of B. stearothermophilus.…”

Section: Resultssupporting

confidence: 64%

“…However, calcium, potassium, phosphate and an energy source were found to be necessary requirements for the survival of Bacillus stearothermophilus cells at elevated temperatures [6]. This finding suggests that an active transport of calcium ions into the cells is of fundamental importance for the heat stability of thermophilic bacteria.…”

Section: Introductionmentioning

confidence: 77%

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Calcium uptake byBacillus stearothermophilus: A requirement for thermophilic growth

Ståhl

Ljunger

1976

FEBS Letters

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“…The importance ofintracellular Ca 2+ in bacterial homeostasis is further supported by the work of Ljunger and Stahl (102,5), who suggested that the uptake of Ca 2+ into bacterial cells is of fundamental importance to the heat stability of thermophilic cells. The existence of a transport system for Ca 2+ was shown during vegetative growth of B. stearothermophilus (5).…”

Section: Role Of Ca 2+ In Bacterial Cellsmentioning

confidence: 91%

Active transport of Ca2+ in bacteria: Bioenergetics and function

Devés

Brodie

1981

Mol Cell Biochem

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The bioenergetics of Ca2+ transport in bacteria are discussed with special emphasis on the interrelationship between transport and other cellular functions such as substrate oxidation by the respiratory chain and oxidative phosphorylation. The unusual polarity of Ca2+ movement provides an exceptional tool to compare active transport and other ATP requiring or generating processes since this ion is actively taken up by everted vesicles in which the coupling-factor ATPase is exposed to the external medium. As inferred from studies with everted vesicles, the active extrusion of Ca2+ by whole cells can be accomplished by substrate driven respiration, hydrolysis of ATP or as in the case of Streptococcus faecalis by a nonhydrolytic unknown process which involves ATP directly. Substrate oxidation and the hydrolysis of ATP result in the generation of a pH gradient which can energize the Ca2+ uptake directly (Ca2+/H+ antiport) or via a secondary Na+ gradient (Ca2+/Na+ antiport). In contrast to exponentially growing cells sporulating Bacilli accumulate Ca2+ during the synthesis of dipicolinic acid. Studies involving Ca2+ transport provided evidence in support of the hypothesis that the Mg2+ ATPase from Escherichia coli not only provides the driving force for various cellular functions but exerts a regulatory role by controlling the permeability of the membrane to protons. The different specificity requirements of various naphthoquinone analogs in the restoration of transport or oxidative phosphorylation, after the natural menaquinone has been destroyed by irradiation, has indicated that a protonmotive force is sufficient to drive active transport. However, in addition to the driving force (protonmotive force) necessary to establish oxidative phosphorylation, a specific spatial orientation of the respiratory components, such as the naphthoquinones, is essential for the utilization of the proton gradient or membrane potential or both. Finally, evidence suggesting that intracellular Ca2+ levels might play a fundamental role in bacterial homeostasis is discussed, in particular the role of Ca2+ in the process of chemotaxis and in conferring bacteria heat stability. A vitamin K-dependent carboxylation reaction has been found in Escherichia coli which is similar to that reported in mammalian systems which results in gamma carboxylation of glutamate residues. Although all of the proteins containing gamma-carboxyglutamate described so far are involved in Ca2+ metabolism, the role of these proteins in Escherichia coli is unknown and remains to be elucidated.

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On the Nature of the Heat Resistance of Thermophilic Bacteria

Cited by 33 publications

References 19 publications

Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells

Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells

Calcium uptake byBacillus stearothermophilus: A requirement for thermophilic growth

Active transport of Ca2+ in bacteria: Bioenergetics and function

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