Diagenetic and detrital origin of moretane anomalies through the Permian–Triassic boundary

French, Katherine L.; Tosca, Nicholas J.; Cao, Changqun; Summons, Roger E.

doi:10.1016/j.gca.2012.01.004

Cited by 49 publications

(20 citation statements)

References 100 publications

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“…In this study, we sought to evaluate proposed links between 2-MeBHP and environmental stress (33,42), based on geological evidence that suggests some sediments contain anomalously high levels of 2-methylhopanes, implicating them as being important for microbial survival (43)(44)(45). Specifically, we investigated the role of 2-MeBHPs in a modern cyanobacterium conferring adaptations to various environmental conditions.…”

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confidence: 99%

Lack of Methylated Hopanoids Renders the Cyanobacterium Nostoc punctiforme Sensitive to Osmotic and pH Stress

Garby

Matys

Ongley

et al. 2017

Appl Environ Microbiol

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To investigate the function of 2-methylhopanoids in modern cyanobacteria, the gene coding for the radical-adenosyl methionine (SAM) methylase protein that acts on the C-2 position of hopanoids was deleted from the filamentous cyanobacterium ATCC 29133S. The resulting Δ mutant lacked all 2-methylhopanoids but was found to produce much higher levels of two bacteriohopanepentol isomers than the wild type. Growth rates of the Δ mutant cultures were not significantly different from those of the wild type under standard growth conditions. Akinete formation was also not impeded by the absence of 2-methylhopanoids. The relative abundances of the different hopanoid structures in akinete-dominated cultures of the wild-type and Δ mutant strains were similar to those of vegetative cell-dominated cultures. However, the Δ mutant was found to have decreased growth rates under both pH and osmotic stress, confirming a role for 2-methylhopanoids in stress tolerance. Evidence of elevated photosystem II yield and NAD(P)H-dependent oxidoreductase activity in the Δ mutant under stress conditions, compared to the wild type, suggested that the absence of 2-methylhopanoids increases cellular metabolic rates under stress conditions. As the first group of organisms to develop oxygenic photosynthesis, are central to the evolutionary history of life on Earth and the subsequent oxygenation of the atmosphere. To investigate the origin of cyanobacteria and the emergence of oxygenic photosynthesis, geobiologists use biomarkers, the remnants of lipids produced by different organisms that are found in geologic sediments. 2-Methylhopanes have been considered indicative of cyanobacteria in some environmental settings, with the parent lipids 2-methylhopanoids being present in many contemporary cyanobacteria. We have created a Δ mutant strain that does not produce 2-methylhopanoids to assess the influence of 2-methylhopanoids on stress tolerance. Increased metabolic activity in the mutant under stress indicates compensatory alterations in metabolism in the absence of 2-methylhopanoids.

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confidence: 99%

Lack of Methylated Hopanoids Renders the Cyanobacterium Nostoc punctiforme Sensitive to Osmotic and pH Stress

Garby

Matys

Ongley

et al. 2017

Appl Environ Microbiol

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“…S3A1–A5). These compounds are bacterial biomarkers that can be related with some depositional environments: it is known that the aerobic methanotrophic bacteria are the precursors of the 3β‐methylhopanoids, while the 2α‐methylhopanes are synthesized by cyanobacteria; in this manner, the abundance of 3β‐methylhopane is related normally with freshwater lacustrine environment, whereas 2α‐methylhopanes have been found predominant in a wide range of hypersaline lacustrine, marine, and freshwater environmental samples . However, the extensive spread of cyanobacteria in several habitats limits this interpretation; additionally, it has been shown that 2‐methylhopanoid compounds can be produced by anoxygenic phototrophs, and then the presence of this compounds alone cannot be regarded as a safe evidence of the presence of cyanobacteria or oxygenic photosynthesis; other evidences should be considered .…”

Section: Resultsmentioning

confidence: 99%

Characterization of crude oil biomarkers using comprehensive two‐dimensional gas chromatography coupled to tandem mass spectrometry

Mogollón

Prata

Reis

et al. 2016

J of Separation Science

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Oil samples from Recôncavo basin (NE Brazil), previously analyzed by traditional techniques such as gas chromatography coupled to tandem mass spectrometry, were evaluated using comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry and comprehensive two-dimensional gas chromatography coupled to tandem mass spectrometry along with simplified methods of samples preparation to evaluate the differences and advantages of these analytical techniques to better understand the development of the organic matter in this basin without altering the normal distribution of the compounds in the samples. As a result, the geochemical parameters calculated by comprehensive two-dimensional gas chromatography coupled to tandem mass spectrometry described better the origin, maturity, and biodegradation of both samples probably by increased selectivity, resolution, and sensitivity inherent of the multidimensional technique. Additionally, the detection of the compounds such as, the C(14α-) homo-26-nor-17α-hopane series, diamoretanes, nor-spergulanes, C19 -C26 A-nor-steranes and 4α-methylsteranes resolved and detected by comprehensive two-dimensional gas chromatography coupled to tandem mass spectrometry were key to classify and differentiate these lacustrine samples according to their maturity and deposition conditions.

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“…Independent modeling also suggests that toxic hydrogen sulfi de would have been upwelling from the deep ocean onto continental shelves and entering the atmosphere (Kump et al, 2005), implying that sulfi de toxicity was a contributing factor to the biological mass extinction in the marine realm as well as on land. Co-occurring with the evidence for euxinia, molecular fossils shed light on other aspects of this event, including transitions in ocean plankton (Cao et al, 2009), and a massive terrestrial weathering event (French et al, 2012;Sephton et al, 2005;Xie et al, 2007).…”

Section: Development Of Molecular Paleontologymentioning

confidence: 91%

Smaller, better, more: Five decades of advances in geochemistry

McLennan

McSween

Summons

2013

The Web of Geological Sciences: Advances, Impacts, and Interactions

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Many of the discoveries made in geochemistry over the last 50 yr have been driven by technological advances that have allowed analysis of smaller samples, attainment of better instrumental precision and accuracy or computational capability, and automation that has provided many more data. These advances occurred during development of revolutionary concepts, such as plate tectonics, which has provided an overarching framework for interpreting many geochemical studies. Also, spacecraft exploration of other planetary bodies, including analyses of returned lunar samples and remote sensing of Mars, has added an additional dimension to geochemistry. Determinations of elemental compositions of minerals and rocks, either through in situ analysis by various techniques (e.g., electron microprobe, secondary ion mass spectrometry [SIMS], synchrotron X-ray fl uorescence [XRF], laser ablation) or bulk analysis (e.g., XRF, inductively coupled plasma-atomic emission spectrometry [ICP-AES], inductively coupled plasma-mass spectrometry [ICP-MS]), have become essential approaches to many geochemical studies at levels of sensitivity and spatial resolution undreamed of fi ve decades ago. Although major-element distributions in igneous rocks have been understood at a basic level for some time, advances using major-element abundances to understand sedimentary provenance and processes have been especially noteworthy during the past half-century. The great diversity of trace elements in terms of geochemical behavior (e.g., lithophile, siderophile, etc.) has made them invaluable to many studies, providing unique constraints on redox conditions, mineral-melt and mineral-fl uid reactions, and planetary differentiation.

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Diagenetic and detrital origin of moretane anomalies through the Permian–Triassic boundary

Cited by 49 publications

References 100 publications

Lack of Methylated Hopanoids Renders the Cyanobacterium Nostoc punctiforme Sensitive to Osmotic and pH Stress

Lack of Methylated Hopanoids Renders the Cyanobacterium Nostoc punctiforme Sensitive to Osmotic and pH Stress

Characterization of crude oil biomarkers using comprehensive two‐dimensional gas chromatography coupled to tandem mass spectrometry

Smaller, better, more: Five decades of advances in geochemistry

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