On Substrate-accelerated Death in Klebsiella aerogenes

Calcott, Peter H.; Postgate, J. R.

doi:10.1099/00221287-70-1-115

Cited by 53 publications

(28 citation statements)

References 10 publications

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“…Extreme sensitivity to growth substrates, often leading to "substrate-accelerated death," has been observed for many combinations of microorganisms and substrates upon a transition from nutrient limitation to nutrient excess. In general, substrate-accelerated death appears to (9,45,46,57). In earlier studies in which maltose-accelerated death was observed in wild-type strains of S. cerevisiae or in mutants affected in glucose catabolite repression, osmotic problems due to rapid maltose uptake and hydrolysis were proposed as causes for this phenomenon (15,16).…”

Section: Discussionmentioning

confidence: 99%

Prolonged Maltose-Limited Cultivation of Saccharomyces cerevisiae Selects for Cells with Improved Maltose Affinity and Hypersensitivity

Jansen

Daran‐Lapujade

Winde

et al. 2004

Appl Environ Microbiol

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Prolonged cultivation (>25 generations) of Saccharomyces cerevisiae in aerobic, maltose-limited chemostat cultures led to profound physiological changes. Maltose hypersensitivity was observed when cells from prolonged cultivations were suddenly exposed to excess maltose. This substrate hypersensitivity was evident from massive cell lysis and loss of viability. During prolonged cultivation at a fixed specific growth rate, the affinity for the growth-limiting nutrient (i.e., maltose) increased, as evident from a decreasing residual maltose concentration. Furthermore, the capacity of maltose-dependent proton uptake increased up to 2.5-fold during prolonged cultivation. Genome-wide transcriptome analysis showed that the increased maltose transport capacity was not primarily due to increased transcript levels of maltose-permease genes upon prolonged cultivation. We propose that selection for improved substrate affinity (ratio of maximum substrate consumption rate and substrate saturation constant) in maltose-limited cultures leads to selection for cells with an increased capacity for maltose uptake. At the same time, the accumulative nature of maltose-proton symport in S. cerevisiae leads to unrestricted uptake when maltose-adapted cells are exposed to a substrate excess. These changes were retained after isolation of individual cell lines from the chemostat cultures and nonselective cultivation, indicating that mutations were involved. The observed trade-off between substrate affinity and substrate tolerance may be relevant for metabolic engineering and strain selection for utilization of substrates that are taken up by proton symport.

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Section: Discussionmentioning

confidence: 99%

Prolonged Maltose-Limited Cultivation of Saccharomyces cerevisiae Selects for Cells with Improved Maltose Affinity and Hypersensitivity

Jansen

Daran‐Lapujade

Winde

et al. 2004

Appl Environ Microbiol

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“…This issue was recently reviewed , Oliver 1993. Dormancy is observed in starved cultures of many copiotrophic bacteria (Calcott & Postgate 1972, Postgate 1976, Reichardt & Morita 1982, Xu et al 1982, Amy & Morita 1983, Baker et al 1983, Kurath & Morita 1983, Roszak et al 1984, Rollins & Colwell 1986, Barcina et al 1989, Byrd & Colwell 1990, Preyer & Oliver 1993.…”

Section: Starvation and Vbnc Cellsmentioning

confidence: 99%

Oligotrophy and pelagic marine bacteria: facts and fiction

Schut¹,

Prins²,

Gottschal³

1997

Aquat. Microb. Ecol.

147

124

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Oligotrophy, or the inability of bacterial cells to propagate at elevated nutrient concentrations, is a controversial phenomenon in microbiology. The exact cause of the unculturability of many indigenous marine bacteria on standard laboratory media has still not been resolved. Unfortunately, the physiology of such cells is difficult to investigate as long as high cell density cultures cannot be obtained. An extensive evaluation of experiments relating to oligotrophy and the cultivation of marine bacteria is presented in this review. When incorporating the findings of studies performed with molecular biological methods, the picture emerges that indigenous marine bacteria can be cultivated under certain cond~tions and that the 'ohgotrophic way of life' is a transient characteristic. Although strong generalisations should not be made w~t h respect to a biological system as diverse as the world's oceans, it should be anticipated that cells with unique physiological characteristics appear to exist in the oceanic system. When combining conventional physiological approaches with molecular biological techniques it is feasible to unveil the phenotypes that go with the encountered genotypes. In view of the enormous complexity of the oceanic system this will prove an ambitious, yet resourceful undertaking.

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“…For this, 0.2 ml of 0.01 (w/v) L-lactate medium [supplemented with 2 "/o (w/v) prefiltered agar] was allowed to set in stainless steel rings (inner diameter, 17 mni; height, 1 mm) placed on glass slides. A low L-lactate concentration was used to approximate as closely as possible to the conditions of the chemostat environment and to minimize the possibility of substrate-accelerated death (Calcott & Postgate, 1972). A suitable dilution of the culture was spread on the surface of the agar, so that each microscopic field at 400x magnificationcontained about 50 organisms.…”

Section: E T H O D Smentioning

confidence: 99%