The effects of modified atmospheres on the growth of psychrotrophic pseudomonads on a surface in a model system

Eyles, M.J.; Moir, Catherine; Davey, Janice A.

doi:10.1016/0168-1605(93)90097-z

Cited by 28 publications

(15 citation statements)

References 11 publications

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“…Elevated CO 2 concentrations have long been known to inhibit bacterial food spoilage and inhibit growth of several isolates (59)(60)(61)(62)(63)(64). Consistent with these observations, CO uptake by A. ehrlichii MLHE-1 was partially inhibited during incubation in an atmosphere with 95% CO 2 /4.8% N 2 /0.2% O 2 at 1,020 mbar relative to activity in an atmosphere with 99.8% N 2 /0.2% O 2 (Fig.…”

Section: Resultssupporting

confidence: 77%

Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in Mars regolith

King

2015

Proc. Natl. Acad. Sci. U.S.A.

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Carbon monoxide occurs at relatively high concentrations (≥800 parts per million) in Mars' atmosphere, where it represents a potentially significant energy source that could fuel metabolism by a localized putative surface or near-surface microbiota. However, the plausibility of CO oxidation under conditions relevant for Mars in its past or at present has not been evaluated. Results from diverse terrestrial brines and saline soils provide the first documentation, to our knowledge, of active CO uptake at water potentials (−41 MPa to −117 MPa) that might occur in putative brines at recurrent slope lineae (RSL) on Mars. Results from two extremely halophilic isolates complement the field observations. Halorubrum str. BV1, isolated from the Bonneville Salt Flats, Utah (to our knowledge, the first documented extremely halophilic CO-oxidizing member of the Euryarchaeota), consumed CO in a salt-saturated medium with a water potential of −39.6 MPa; activity was reduced by only 28% relative to activity at its optimum water potential of −11 MPa. A proteobacterial isolate from hypersaline Mono Lake, California, Alkalilimnicola ehrlichii MLHE-1, also oxidized CO at low water potentials (−19 MPa), at temperatures within ranges reported for RSL, and under oxic, suboxic (0.2% oxygen), and anoxic conditions (oxygen-free with nitrate). MLHE-1 was unaffected by magnesium perchlorate or low atmospheric pressure (10 mbar). These results collectively establish the potential for microbial CO oxidation under conditions that might obtain at local scales (e.g., RSL) on contemporary Mars and at larger spatial scales earlier in Mars' history. Geological, geochemical, and geomorphological observations have provided definitive evidence for large, ancient fluvial systems that might have been conducive to life (8-13), but the timing, temperature, and composition of surface water have been controversial (14-17). Although unequivocal evidence for contemporary liquid water reservoirs has not yet been obtained, experimental evidence suggests plausible conditions under which brines might form (18), and observations from the Mars Reconnaissance Orbiter suggest that recurring slope lineae (RSL) at latitudes between 32°S and 48°S might develop in association with seasonally moderate conditions during late spring-summer (19-21). McEwen et al. (19) have proposed that these features can be best explained by near-surface liquid water brines that form between temperatures of about −10°C and 25°C during late spring-summer.However, even if liquid water was at one time or is now sufficient to support microbial life, energy sources that could sustain metabolism in near-surface regolith have not been identified. Although the 1976 Viking lander results appeared to exclude surface organic matter (e.g., 22, 23), recent evidence suggests that low organic matter levels might indeed occur in some deposits (e.g., 12). Even so, it is uncertain whether this material exists in a form or concentrations suitable for microbial use.The Martian atmosphere has largely been ign...

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Section: Resultssupporting

confidence: 77%

Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in Mars regolith

King

2015

Proc. Natl. Acad. Sci. U.S.A.

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“…In several studies, the sensitivity of Pseudomonas spp. towards elevated CO 2 is reported (Eyles et al. 1993; Moir et al.…”

Section: Discussionmentioning

confidence: 97%

“…2005). Eyles et al. (1993) mentioned that concentrations as low as 10% (v/v) can reduce the growth rate of pseudomonads.…”

Section: Introductionmentioning

confidence: 99%

Growth of Pseudomonas fluorescens in modified atmosphere packaged tofu

Stoops

Maes

Claes

et al. 2012

Letters in Applied Microbiology

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Aims: The objective was to study the growth of Pseudomonas in a food product (tofu) where it typically occurs as a spoilage organism, and when this product is stored under modified atmosphere. Methods and Results: A Pseudomonas strain was isolated from the endogenous microflora of tofu. Tofu was inoculated with the strain, packaged in different gas conditions (air, 100% N2, 30% CO2/70% N2 or 100% CO2) and stored under refrigerated conditions. Microbial loads and the headspace gas composition were monitored during storage. Conclusions: The strain was capable of growing in atmospheres containing no or limited amounts of oxygen and increased amounts of carbon dioxide. Even when 100% CO2 was used, growth could not be inhibited completely. Significance and Impact of Study: In contrast to the general characteristics of the genus Pseudomonas (strictly aerobic, highly sensitive to CO2), it should not be expected in the food industry that removing oxygen from the food package and increasing the carbon dioxide content, combined with cold storage, will easily avoid spoilage by Pseudomonas species. Guarantee of hygienic standards and combination of strategies with other microbial growth inhibiting measures should be implemented.

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“…Some investigations have been done in liquid media using tissue culture plates (Eklund and Jarmund, 1983;Hao and Brackett, 1993), fermenters flushed continuously with a gas mixture (Molin, 1983), or buffered broth (Hendricks and Hotchkiss, 1997). Only a few reports (Rasavilar and Genigeorgis, 1992;Kimura et al, 1997) of bacterial growth on agar plates which simulates growth conditions in MA-stored food, and very few reports (Golden et al, 1989;Eyles et al, 1993) have considered the decrease in pH caused by dissolution of CO 2 . Eyles et al (1993) evaluated the growth and survival of psychrotrophic pseudomonads at 5 and 15ЊC, while minimizing the pH decrease caused with CO 2 dissolution using buffered agar media.…”

Section: Introductionmentioning

confidence: 99%

“…Only a few reports (Rasavilar and Genigeorgis, 1992;Kimura et al, 1997) of bacterial growth on agar plates which simulates growth conditions in MA-stored food, and very few reports (Golden et al, 1989;Eyles et al, 1993) have considered the decrease in pH caused by dissolution of CO 2 . Eyles et al (1993) evaluated the growth and survival of psychrotrophic pseudomonads at 5 and 15ЊC, while minimizing the pH decrease caused with CO 2 dissolution using buffered agar media. However, the pH values were not presented, so the direct effects of CO 2 alone could not be determined.…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Inhibition of Escherichia coli and Staphylococcus aureus on a pH‐adjusted Surface in a Model System

Kimura

Yoshiyama

Fujii

1999

Journal of Food Science

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Growth of Escherichia coli and Staphylococcus aureus on the surface of TrypticaseSoy Agar (TSA) packaged with various CO 2 partial pressures (0, 20, 40, 60, 80, 100%, balance N 2 ) was compared to the control (N 2 100%) on TSA in which the pH was adjusted to equal that in CO 2 atmospheres at 15ЊC and 30ЊC. At 15ЊC, the biostatic effect was noted with all CO 2 partial pressures for both species. At 30ЊC, the biostatic effect of CO 2 was almost completely nullified for E. coli, but that for S. aureus was still effective. S. aureus was more sensitive to the inhibitory effects of CO 2 than E. coli at both the temperatures.mission rate of the film was 8.7 cc/m 2 /24h/ atm. Details as to the packaging methods and gas analyses have been described previously (Kimura et al., 1996).The surface pH of the agar was measured with a pH meter (Horiba M-8, Kyoto, Japan) equipped with a flat combination electrode (T-8) immediately (with a few seconds) after opening. The bags were opened 3, 30, 60, 90, and 120 min after packaging. The pH was averaged from the values of three replicate plates contained in different packages.We examined the growth inhibitory effect of CO 2 alone, not in combination with decreasing pH. For this purpose, the pH of N 2 -packaged media was adjusted to the same level as that which occurred on dissolution of headspace CO 2 . Since high CO 2 decreased the pH to Ͻ6.0 when unbuffered TSA medium was used, the media to be packaged with CO 2 were also Tris buffered (0.02M) to minimize the pH decrease. After the pH had been adjusted to 8.0 initially, the fall in pH after MA treatments was less pronounced. The surface pH on TSA stored for 120 min after MAP treatments was 6.7 for 20% CO 2 , 6.3 for 40% CO 2 , 6.2 for 60% CO 2 , 6.0 for 80% CO 2 , 5.9 for 100% CO 2 in 15°C experiments and pH 7.0 for 20% CO 2 , 6.8 for 40% CO 2 , 6.6 for 60% CO 2 , pH 6.4 for 80% CO 2 , and 6.2 for 100% CO 2 in 30° C experiments. The pH of N 2 -packaged media (also buffered with 0.02M Tris) for comparing bacterial growth was adjusted to the corresponding values using 0.1N HCl. The MA treatment with N 2 did not change pH on the agar surface.

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The effects of modified atmospheres on the growth of psychrotrophic pseudomonads on a surface in a model system

Cited by 28 publications

References 11 publications

Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in Mars regolith

Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in Mars regolith

Growth of Pseudomonas fluorescens in modified atmosphere packaged tofu

Carbon Dioxide Inhibition of Escherichia coli and Staphylococcus aureus on a pH‐adjusted Surface in a Model System

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