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A traditional Japanese-style salt field is a niche for haloarchaeal strains that can survive in 0.5% salt solution.

Fukushima T, Usami R, Kamekura M - Saline Syst. (2007)

Bottom Line: Survival rates in 3% and 0.5% SW (Salt Water, solutions containing salts in approximately the same proportions as found in seawater) solutions at 37 degrees C differed considerably depending on the strains.The inside of the silt particles is filled with concentrated salt solution and kept intact even upon suspension in rainwater.Possible origins of the haloarchaea isolated in this study are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan. bioeng@mail.cc.eng.toyo.ac.jp

ABSTRACT

Background: Most of the haloarchaeal strains have been isolated from hypersaline environments such as solar evaporation ponds, salt lakes, or salt deposits, and they, with some exceptions, lyse or lose viability in very low-salt concentrations. There are no salty environments suitable for the growth of haloarchaea in Japan. Although Natrialba asiatica and Haloarcula japonica were isolated many years ago, the question, "Are haloarchaea really thriving in natural environments of Japan?" has remained unanswered.

Results: Ten strains were isolated from a traditional Japanese-style salt field at Nie, Noto Peninsula, Japan by plating out the soil samples directly on agar plates containing 30% (w/v) salts and 0.5% yeast extract. They were most closely related to strains of three genera, Haladaptatus, Halococcus, and Halogeometricum. Survival rates in 3% and 0.5% SW (Salt Water, solutions containing salts in approximately the same proportions as found in seawater) solutions at 37 degrees C differed considerably depending on the strains. Two strains belonging to Halogeometricum as well as the type strain Hgm. borinquense died and lysed immediately after suspension. Five strains that belonged to Halococcus and a strain that may be a member of Halogeometricum survived for 1-2 days in 0.5% SW solution. Two strains most closely related to Haladaptatus possessed extraordinary strong tolerance to low salt conditions. About 20 to 34% of the cells remained viable in 0.5% SW after 9 days incubation.

Conclusion: In this study we have demonstrated that haloarchaea are really thriving in the soil of Japanese-style salt field. The haloarchaeal cells, particularly the fragile strains are suggested to survive in the micropores of smaller size silt fraction, one of the components of soil. The inside of the silt particles is filled with concentrated salt solution and kept intact even upon suspension in rainwater. Possible origins of the haloarchaea isolated in this study are discussed.

No MeSH data available.


Related in: MedlinePlus

A map of Noto Peninsula. The Nie salt field resides 3 km east of Sosogi in the northern part.
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Figure 2: A map of Noto Peninsula. The Nie salt field resides 3 km east of Sosogi in the northern part.

Mentions: In October 1985, scientists Horikoshi and Grant visited a salt field at Nie (Fig. 1) located on the coast of the Sea of Japan 3 km east of Sosogi of Noto Peninsula (see Fig. 2). They collected five soil samples from the salt field, and isolated seven strains on agar plates of a complex medium containing 4 M NaCl. Only one strain was shown to be extremely halophilic requiring at least 15% NaCl for growth [10]. It was reported that the cells of strain TR-1, designated as Haloarcula japonica [11], lysed upon suspension in 5% NaCl solution [12]. Although exact figures are not available for the Nie area, the statistics by Japan Meteorological Agency tell us that annual rainfall of Wajima City, only 22 kilometers west of Nie salt field, ranged from 1976 to 2560 mm during the last five years (2002–2006) with a mean of 2200 mm, compared to 1295 to1854 mm of Tokyo. It is known that the west coast of Australia, where solar salterns are operated, is arid with annual rainfall less than 300 mm (Bureau of Meteorology of Australian Government). In rainy season, the soil layer is sometimes flooded with heavy rainfall. Since 1986, however, no reports were published on the isolation of other haloarchaeal strains from natural environment in Japan. The question "Are haloarchaea really thriving in regions of Japan?" has not been answered yet.


A traditional Japanese-style salt field is a niche for haloarchaeal strains that can survive in 0.5% salt solution.

Fukushima T, Usami R, Kamekura M - Saline Syst. (2007)

A map of Noto Peninsula. The Nie salt field resides 3 km east of Sosogi in the northern part.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1828056&req=5

Figure 2: A map of Noto Peninsula. The Nie salt field resides 3 km east of Sosogi in the northern part.
Mentions: In October 1985, scientists Horikoshi and Grant visited a salt field at Nie (Fig. 1) located on the coast of the Sea of Japan 3 km east of Sosogi of Noto Peninsula (see Fig. 2). They collected five soil samples from the salt field, and isolated seven strains on agar plates of a complex medium containing 4 M NaCl. Only one strain was shown to be extremely halophilic requiring at least 15% NaCl for growth [10]. It was reported that the cells of strain TR-1, designated as Haloarcula japonica [11], lysed upon suspension in 5% NaCl solution [12]. Although exact figures are not available for the Nie area, the statistics by Japan Meteorological Agency tell us that annual rainfall of Wajima City, only 22 kilometers west of Nie salt field, ranged from 1976 to 2560 mm during the last five years (2002–2006) with a mean of 2200 mm, compared to 1295 to1854 mm of Tokyo. It is known that the west coast of Australia, where solar salterns are operated, is arid with annual rainfall less than 300 mm (Bureau of Meteorology of Australian Government). In rainy season, the soil layer is sometimes flooded with heavy rainfall. Since 1986, however, no reports were published on the isolation of other haloarchaeal strains from natural environment in Japan. The question "Are haloarchaea really thriving in regions of Japan?" has not been answered yet.

Bottom Line: Survival rates in 3% and 0.5% SW (Salt Water, solutions containing salts in approximately the same proportions as found in seawater) solutions at 37 degrees C differed considerably depending on the strains.The inside of the silt particles is filled with concentrated salt solution and kept intact even upon suspension in rainwater.Possible origins of the haloarchaea isolated in this study are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan. bioeng@mail.cc.eng.toyo.ac.jp

ABSTRACT

Background: Most of the haloarchaeal strains have been isolated from hypersaline environments such as solar evaporation ponds, salt lakes, or salt deposits, and they, with some exceptions, lyse or lose viability in very low-salt concentrations. There are no salty environments suitable for the growth of haloarchaea in Japan. Although Natrialba asiatica and Haloarcula japonica were isolated many years ago, the question, "Are haloarchaea really thriving in natural environments of Japan?" has remained unanswered.

Results: Ten strains were isolated from a traditional Japanese-style salt field at Nie, Noto Peninsula, Japan by plating out the soil samples directly on agar plates containing 30% (w/v) salts and 0.5% yeast extract. They were most closely related to strains of three genera, Haladaptatus, Halococcus, and Halogeometricum. Survival rates in 3% and 0.5% SW (Salt Water, solutions containing salts in approximately the same proportions as found in seawater) solutions at 37 degrees C differed considerably depending on the strains. Two strains belonging to Halogeometricum as well as the type strain Hgm. borinquense died and lysed immediately after suspension. Five strains that belonged to Halococcus and a strain that may be a member of Halogeometricum survived for 1-2 days in 0.5% SW solution. Two strains most closely related to Haladaptatus possessed extraordinary strong tolerance to low salt conditions. About 20 to 34% of the cells remained viable in 0.5% SW after 9 days incubation.

Conclusion: In this study we have demonstrated that haloarchaea are really thriving in the soil of Japanese-style salt field. The haloarchaeal cells, particularly the fragile strains are suggested to survive in the micropores of smaller size silt fraction, one of the components of soil. The inside of the silt particles is filled with concentrated salt solution and kept intact even upon suspension in rainwater. Possible origins of the haloarchaea isolated in this study are discussed.

No MeSH data available.


Related in: MedlinePlus