Microbial transport: Adaptations to natural environments

Konings, Wil N.

doi:10.1007/s10482-006-9089-3

Cited by 87 publications

(65 citation statements)

References 102 publications

(95 reference statements)

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“…Similar to the situation for some Haloarchaea, which use bacteriorhodopsin under oxygen-limiting conditions (18,19,26,27), low respiratory rates may trigger PR expression or activity in marine bacteria, as well. The PR-generated proton-motive force can also be directly coupled to other energy-requiring cellular activities, including flagellar motility or active transport of solutes into or out of the cell (32)(33)(34). This phenomenon was recently demonstrated by the coupling of PR activity to flagellar rotation in E. coli (31).…”

Section: Discussionmentioning

confidence: 99%

Proteorhodopsin photosystem gene expression enables photophosphorylation in a heterologous host

Martínez

Bradley

Waldbauer

et al. 2007

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

171

200

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Proteorhodopsins (PRs) are retinal-containing proteins that catalyze light-activated proton efflux across the cell membrane. These photoproteins are known to be globally distributed in the ocean's photic zone, and they are found in a diverse array of Bacteria and Archaea. Recently, light-enhanced growth rates and yields have been reported in at least one PR-containing marine bacterium, but the physiological basis of light-activated growth stimulation has not yet been determined. To describe more fully PR photosystem genetics and biochemistry, we functionally surveyed a marine picoplankton large-insert genomic library for recombinant clones expressing PR photosystems in vivo. Our screening approach exploited transient increases in vector copy number that significantly enhanced the sensitivity of phenotypic detection. Two genetically distinct recombinants, initially identified by their orange pigmentation, expressed a small cluster of genes encoding a complete PR-based photosystem. Genetic and biochemical analyses of transposon mutants verified the function of gene products in the photopigment and opsin biosynthetic pathways. Heterologous expression of six genes, five encoding photopigment biosynthetic proteins and one encoding a PR, generated a fully functional PR photosystem that enabled photophosphorylation in recombinant Escherichia coli cells exposed to light. Our results demonstrate that a single genetic event can result in the acquisition of phototrophic capabilities in an otherwise chemoorganotrophic microorganism, and they explain in part the ubiquity of PR photosystems among diverse microbial taxa.photoheterotrophy ͉ rhodopsin ͉ lateral gene transfer ͉ marine ͉ metagenomics

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Section: Discussionmentioning

confidence: 99%

Proteorhodopsin photosystem gene expression enables photophosphorylation in a heterologous host

Martínez

Bradley

Waldbauer

et al. 2007

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

171

200

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“…Most bitumens contained more aromatic than saturated hydrocarbons, consistent with the highly aromatic character of the kerogen ( Table 1). All of these characteristics are expected of highly thermally mature bitumen-kerogen associations where diagenetic and catagenetic reactions have proceeded for long periods and where the disproportionation of the original organic matter 34 J.R. Waldbauer et al / Precambrian Research 169 (2009) [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] into disordered, aromatised carbon and light hydrocarbons is nearing completion.…”

Section: Saturated and Aromatic Hydrocarbonsmentioning

confidence: 99%

“…Steranes bearing additional methylation in the ring system (including 4-methyl and 4,4-dimethyl steranes) were not detected in any of the Griqualand core samples, despite use of sensitive MRM techniques to search for them specifically. While such methylsteranes cannot truly be said to be absent from the rocks -only to be below the detection limit of 38 J.R. Waldbauer et al / Precambrian Research 169 (2009) [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] the methods employed -it is clear that the precursors of desmethyl steranes were a much larger proportion of the organic matter input to these sediments than were methylsteroids. Fig.…”

Section: Steranesmentioning

confidence: 99%

“…Grosjean and Logan (2007) and Brocks et al (2008) have highlighted the utility of branched alkanes with quaternary carbons (BAQCs) as tracers of polyethylene contamination in drill cores. Using selected ion and difference chromatograms, the Agouron core extracts were examined for several series of BAQCs, including 2,2-through 9,9-40 J.R. Waldbauer et al / Precambrian Research 169 (2009) [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] Fig. 8.…”

Section: Absence Of Petrochemical and Phanerozoic Signaturesmentioning

confidence: 99%

“…Waldbauer et al / Precambrian Research 169 (2009) [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] …”

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Molecular biogeochemistry of modern and ancient marine microbes

Waldbauer¹

2010

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Biological activity has shaped the surface of the earth in numerous ways, but life's most pervasive and persistent global impact has been the secular oxidation of the surface environment. Through primary production -the biochemical reduction of carbon dioxide to synthesize biomass -large amounts of oxidants such as molecular oxygen, sulfate and ferric iron have accumulated in the ocean, atmosphere and crust, fundamentally altering the chemical environment of the earth's surface. This thesis addresses aspects of the role of marine microorganisms in driving this process. In the first section of the thesis, biomarkers (hydrocarbon molecular fossils) are used to investigate the early history of microbial diversity and biogeochemistry. Molecular fossils from the Transvaal Supergroup, South Africa, document the presence in the oceans of a diverse microbiota, including eukaryotes, as well as oxygenic photosynthesis and aerobic biochemistry, by ca. 2.7Ga. Experimental study of the oxygen requirements of steroid biosynthesis suggests that sterane biomarkers in late Archean rocks are consistent with the persistence of microaerobic surface ocean environments long before the initial oxygenation of the atmosphere. In the second part, using Prochlorococcus (a marine cyanobacterium that is the most abundant primary producer on earth today) as a model system, we explored how microbes use the limited nutrient resources available in the marine environment to make the protein catalysts that enable primary production. Quantification of the Prochlorococcus proteome over the diel cell-division cycle reveals that protein abundances are distinct from transcript-level dynamics, and that small temporal shifts in enzyme levels can redirect metabolic fluxes. This thesis illustrates how molecular techniques can contribute to a systems-level understanding of biogeochemical processes, which will aid in reconstructing the past of, and predicting future change in, earth surface environments. ACKNOWLEDGMENTSI have incurred many debts of gratitude and appreciation over the course of this work. None are greater than those to my advisors, Penny Chisholm and Roger Summons, who allowed and enabled me to pursue such a wide range of scientific interests and offered their help and advice every step of the way. I have been very lucky to have had the chance to learn so much during my Ph.D., and none of that would have been possible without their guidance and support.I have also had the great fortune to know and work with all the members of the Chisholm and Summons labs, who have made this an enjoyable and rewarding place to be. I am especially grateful to Laura Sherman for her skill and dedication in analyzing biomarkers in the late Archean cores -it was truly getting blood from a stone. I was lucky to collaborate with Sébastien Rodrigue, whose expertise and collegiality made the diel experiment even more fruitful than I could have hoped. IntroductionThe coevolution of life and earth surface environments is central to the history and functionin...

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Resource Control of Bacterial Dynamics in the Sea

Church

2008

Microbial Ecology of the Oceans

116

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Microbial transport: Adaptations to natural environments

Cited by 87 publications

References 102 publications

Proteorhodopsin photosystem gene expression enables photophosphorylation in a heterologous host

Proteorhodopsin photosystem gene expression enables photophosphorylation in a heterologous host

Molecular biogeochemistry of modern and ancient marine microbes

Resource Control of Bacterial Dynamics in the Sea

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