Lipid accumulation in prokaryotic microorganisms from arid habitats

Hauschild, Philippa; Röttig, Annika; Madkour, Mohamed Hussein; Al-Ansari, Ahmed M.; Almakishah, Naief H.; Steinbüchel, Alexander

doi:10.1007/s00253-017-8149-0

Cited by 24 publications

(10 citation statements)

References 112 publications

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“…The sharing and differential partitioning of this exometabolite pool allows the rapid buildup and accumulation of biomass. In response to xeric stress, heterotrophs upregulate the synthesis of reserve molecules, such as glycogen (72), wax esters (73), and lipids (74).…”

Section: Energy Reserve Hypothesismentioning

confidence: 99%

Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems

et al. 2020

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Microbial life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation. Whereas photoautotrophs are restricted to specific niches in extreme deserts, metabolically versatile heterotrophs persist even in the hyper-arid topsoils of the Atacama Desert and Antarctica. At least three distinct strategies appear to allow such microorganisms to conserve energy in these oligotrophic environments: degradation of organic energy reserves, rhodopsin- and bacteriochlorophyll-dependent light harvesting, and oxidation of the atmospheric trace gases hydrogen and carbon monoxide. In turn, these principles are relevant for understanding the composition, functionality, and resilience of desert ecosystems, as well as predicting responses to the growing problem of desertification.

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Section: Energy Reserve Hypothesismentioning

confidence: 99%

Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems

et al. 2020

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“…The "energy reserve hypothesis" proposes that these communities are sustained by the organic carbon that becomes transiently available following hydration events, through photoautotrophic activity and other processes. Chemoheterotrophs are hypothesized to store some of the organic carbon released following hydration events and use it as an energy source to maintain themselves in predominantly dormant states during subsequent long-term desiccation (6,(29)(30)(31). Hence, they are adapted to a feast-and-famine lifestyle.…”

mentioning

confidence: 99%

Hydrogen-Oxidizing Bacteria Are Abundant in Desert Soils and Strongly Stimulated by Hydration

et al. 2020

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How the diverse bacterial communities inhabiting desert soils maintain energy and carbon needs is much debated. Traditionally, most bacteria are thought to persist by using organic carbon synthesized by photoautotrophs following transient hydration events. Recent studies focused on Antarctic desert soils have revealed, however, that some bacteria use atmospheric trace gases, such as hydrogen (H2), to conserve energy and fix carbon independently of photosynthesis. In this study, we investigated whether atmospheric H2 oxidation occurs in four nonpolar desert soils and compared this process to photosynthesis. To do so, we first profiled the distribution, expression, and activities of hydrogenases and photosystems in surface soils collected from the South Australian desert over a simulated hydration-desiccation cycle. Hydrogenase-encoding sequences were abundant in the metagenomes and metatranscriptomes and were detected in actinobacterial, acidobacterial, and cyanobacterial metagenome-assembled genomes. Native dry soil samples mediated H2 oxidation, but rates increased 950-fold following wetting. Oxygenic and anoxygenic phototrophs were also detected in the community but at lower abundances. Hydration significantly stimulated rates of photosynthetic carbon fixation and, to a lesser extent, dark carbon assimilation. Hydrogenase genes were also widespread in samples from three other climatically distinct deserts, the Namib, Gobi, and Mojave, and atmospheric H2 oxidation was also greatly stimulated by hydration at these sites. Together, these findings highlight that H2 is an important, hitherto-overlooked energy source supporting bacterial communities in desert soils. Contrary to our previous hypotheses, however, H2 oxidation occurs simultaneously rather than alternately with photosynthesis in such ecosystems and may even be mediated by some photoautotrophs. IMPORTANCE Desert ecosystems, spanning a third of the earth’s surface, harbor remarkably diverse microbial life despite having a low potential for photosynthesis. In this work, we reveal that atmospheric hydrogen serves as a major previously overlooked energy source for a large proportion of desert bacteria. We show that both chemoheterotrophic and photoautotrophic bacteria have the potential to oxidize hydrogen across deserts sampled across four continents. Whereas hydrogen oxidation was slow in native dry deserts, it increased by three orders of magnitude together with photosynthesis following hydration. This study revealed that continual harvesting of atmospheric energy sources may be a major way that desert communities adapt to long periods of water and energy deprivation, with significant ecological and biogeochemical ramifications.

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“…Our results indicate that SE formation is conserved in sterol-degrading bacteria, suggesting that this trait might play important roles in these environments. Supporting this hypothesis, most neutral-lipid accumulating Actinobacteria isolated from soil samples (52) belong to taxa in which the ability to degrade sterols is conserved (22) and are thus likely to produce SEs. De novo synthesis of sterols is rare in bacteria, being largely restricted to Myxococcales and Methylococcales (20).…”

Section: Discussionmentioning

confidence: 94%

Steryl ester formation and accumulation in steroid-degrading bacteria

Holert

Brown

Hashimi

et al. 2019

Preprint

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16Steryl esters (SEs) are important storage compounds in many eukaryotes and are often 17 prominent components of intracellular lipid droplets. Here we demonstrate that selected 18Actino-and Proteobacteria growing on sterols are also able to synthesize SEs and to 19 sequester them in cytoplasmic lipid droplets. We found cholesteryl ester (CE) formation in 20 members of the actinobacterial genera Rhodococcus, Mycobacterium, and Amycolatopsis as 21 well as several members of the proteobacterial Cellvibrionales order. CEs maximally 22 environmental stress conditions to increase their survival in environments with fluctuating 48 nutrient conditions (1). A much smaller subset of bacteria are oleaginous and accumulate 49 neutral lipids, namely triacylglycerols (TAGs) and wax esters (WEs), as a prominent class of 50 storage compounds. Although TAG and WE synthesis is rarely described in other bacteria, 51 their accumulation is widespread within the actinobacterial genera Streptomyces, Nocardia, 52

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Lipid accumulation in prokaryotic microorganisms from arid habitats

Cited by 24 publications

References 112 publications

Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems

Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems

Hydrogen-Oxidizing Bacteria Are Abundant in Desert Soils and Strongly Stimulated by Hydration

Steryl ester formation and accumulation in steroid-degrading bacteria

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