Halobacterium volcanii spec. nov., a Dead Sea halobacterium with a moderate salt requirement

Mullakhanbhai, M F; Larsen, Helge

doi:10.1007/bf00447326

Cited by 371 publications

(247 citation statements)

References 11 publications

Supporting

Mentioning

235

Contrasting

Unclassified

Order By: Relevance

“…In the original report of the strain, it was shown that disruption of the plasma membrane by osmotic lysis upon transfer of cells into water yielded small, sealed membrane vesicles [32]. Unfortunately, the topological orientation and preservation of membrane protein function in these vesicles was not determined.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Inverted Membrane Vesicles from the Halophilic Archaeon Haloferax volcanii

Ring

Eichler

2001

Journal of Membrane Biology

View full text Add to dashboard Cite

Abstract. Membrane-related processes in archaea, the third and most-recently described domain of life, are in general only poorly understood. One obstacle to a functional understanding of archaeal membrane-associated activities corresponds to a lack of archaeal model membrane systems. In the following, characterization of inverted archaeal membrane vesicles, prepared from the halophilic archaeon Haloferax volcanii, is presented. The inverted topology of the vesicles was revealed by defining the orientation of membrane-bound enzymes that in intact cells normally face the cytoplasm or of other protein markers, known to face the exterior medium in intact cells. Electron microscopy, protease protection assays and lectin-binding experiments confirmed the sealed nature of the vesicles. Upon alkalinization of the external medium, the vesicles were able to generate ATP, reflecting the functional nature of the membrane preparation. The availability of preparative scale amounts of inverted archaeal membrane vesicles provides a platform for the study of various membranerelated phenomena in archaea.

show abstract

Section: Discussionmentioning

confidence: 99%

Characterization of Inverted Membrane Vesicles from the Halophilic Archaeon Haloferax volcanii

Ring

Eichler

2001

Journal of Membrane Biology

View full text Add to dashboard Cite

show abstract

“…The natural adaption of proteins to halophilic habitats poses significant challenges, and proteins may express inactive or form inclusion bodies. Refolding procedures may restore enzyme activity (Connaris et al 1998a ;Mullakhanbhai and Larsen 1975 ), but this method is not general, and many enzymes remain inactive (Timpson et al 2012 ).…”

Section: Introductionmentioning

confidence: 99%

“…A typical example is the application of the archaea Haloferax volcanii, which was isolated from the Dead Sea by Benjamin Volcani in the 1940s (22). For optimal growth, it requires 2.6 M NaCl and a temperature between 42 and 45 °C (Mullakhanbhai and Larsen 1975 ).…”

Section: Introductionmentioning

confidence: 99%

Production of halophilic proteins using Haloferax volcanii H1895 in a stirred-tank bioreactor

Strillinger

Grötzinger

Allers

et al. 2015

Appl Microbiol Biotechnol

View full text Add to dashboard Cite

The success of biotechnological processes is based on the availability of efficient and highly specific biocatalysts, which can satisfy industrial demands. Extreme and remote environments like the deep brine pools of the Red Sea represent highly interesting habitats for the discovery of novel halophilic and thermophilic enzymes. Haloferax volcanii constitutes a suitable expression system for halophilic enzymes obtained from such brine pools. We developed a batch process for the cultivation of H. volcanii H1895 in controlled stirred-tank bioreactors utilising knockouts of components of the flagella assembly system. The standard medium Hv-YPC was supplemented to reach a higher cell density. Without protein expression, cell dry weight reaches 10 g L . Two halophilic alcohol dehydrogenases were expressed under the control of the tryptophanase promoter p.tna with 16.8 and 3.2 mg g , respectively, at a maximum cell dry weight of 6.5 g L . Protein expression was induced by the addition of L-tryptophan. Investigation of various expression strategies leads to an optimised two-step induction protocol introducing 6 mM L-tryptophan at an OD of 0.4 followed by incubation for 16 h and a second induction step with 3 mM L-tryptophan followed by a final incubation time of 4 h. Compared with the uncontrolled shaker-flask cultivations used until date, dry cell mass concentrations were improved by a factor of more than 5 and cell-specific enzyme activities showed an up to 28-fold increased yield of the heterologous proteins.

show abstract

“…Two such events have been documented: in 1980, and even more dramatically in 1992, when the upper 5 m of the water column was diluted up to 70%, supporting a density of Archaea up to 3.5 Â 10 7 ml -1 , coloring the Dead Sea water red . A number of species of halophilic Archaea have been isolated from the Dead Sea, including Haloferax volcanii (Mullakhanbhai and Larsen, 1975), Haloarcula marismortui (Oren et al, 1990), Halorubrum sodomense (Oren, 1983) and Halobaculum gomorrense . However, polar lipid analyses of biomass collected during Dead Sea blooms suggested that these isolates were not the major components of the microbial community at the time (Oren and Gurevich, 1993).…”

Section: Introductionmentioning

confidence: 99%

Comparative community genomics in the Dead Sea: an increasingly extreme environment

et al. 2009

View full text Add to dashboard Cite

Owing to the extreme salinity (B10 times saltier than the oceans), near toxic magnesium levels (B2.0 M Mg 2 þ ), the dominance of divalent cations, acidic pH (6.0) and high-absorbed radiation flux rates, the Dead Sea represents a unique and harsh ecosystem. Measures of microbial presence (microscopy, pigments and lipids) indicate that during rare bloom events after exceptionally rainy seasons, the microbial communities can reach high densities. However, most of the time, when the Dead Sea level is declining and halite is precipitating from the water column, it is difficult to reliably measure the presence of microorganisms and their activities. Although a number of halophilic Archaea have been previously isolated from the Dead Sea, polar lipid analyses of biomass collected during Dead Sea blooms suggested that these isolates were not the major components of the microbial community of these blooms. In this study, in an effort to characterize the perennial microbial community of the Dead Sea and compare it with bloom assemblages, we performed metagenomic analyses of concentrated biomass from hundreds of liters of brine and of microbial material from the last massive Dead Sea bloom. The difference between the two conditions was reflected in community composition and diversity, in which the bloom was different and less diverse from the residual brine population. The distributional patterns of microbial genes suggested Dead Sea community trends in mono-and divalent cation metabolisms as well as in transposable elements. This may indicate possible mechanisms and pathways enabling these microbes to survive in such a harsh environment.

show abstract

Halobacterium volcanii spec. nov., a Dead Sea halobacterium with a moderate salt requirement

Cited by 371 publications

References 11 publications

Characterization of Inverted Membrane Vesicles from the Halophilic Archaeon Haloferax volcanii

Characterization of Inverted Membrane Vesicles from the Halophilic Archaeon Haloferax volcanii

Production of halophilic proteins using Haloferax volcanii H1895 in a stirred-tank bioreactor

Comparative community genomics in the Dead Sea: an increasingly extreme environment

Contact Info

Product

Resources

About