Novel hopanoid cyclases from the environment

Pearson, Ann; Page, Sarah; Jorgenson, Tyler L.; Fischer, Woodward W.; Higgins, Meytal B.

doi:10.1111/j.1462-2920.2007.01331.x

Cited by 116 publications

(102 citation statements)

References 68 publications

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“…Biohopanoids are pentacyclic triterpenoids produced by a wide range of bacteria 78 (Pearson et al, 2007;Rohmer et al, 1984) and appear to perform a regulating and 79 rigidifying function similar to sterols in eukaryotes (Kannenberg and Poralla, 1999; 80 Sáenz et al, 2015). These compounds can be subdivided into two groups: simple 81 hopanoids with a C30 ring system (e.g.…”

Section: Introduction 77mentioning

confidence: 99%

Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives

Inglis

Naafs

Zheng

et al. 2018

Geochimica et Cosmochimica Acta

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However, in some modern peatlands, the C31 hopane is present as the 'thermally-28 mature' 17α,21β(H) stereoisomer. This has traditionally been ascribed to 29 isomerisation at the C-17 position catalysed by the acidic environment. However, 30 recent work has argued that temperature and/or hydrology also exert a control upon 31 hopane isomerisation. Such findings complicate the application of geohopanoids as 32 palaeoenvironmental proxies. However, due to the small number of peats that have 33 been studied, as well as the lack of peatland diversity sampled, the environmental 34 controls regulating geohopanoid isomerisation remain poorly constrained. Here, we 35 undertake a global approach to investigate the occurrence, distribution and 36 diagenesis of geohopanoids within peat, combining previously published and newly 37 generated data (n = 395) from peatlands with a wide temperature (-1 to 27°C) and 38 pH (3 to 8) range. Our results indicate that peats are characterised by a wide range 39 of geohopanoids. However, the C31 hopane and C32 hopanoic acid (and occasionally 40 the C32 hopanol) typically dominate. C32 hopanoic acids occur as αβ-and ββ-41 stereoisomers, with the ββ-isomer typically dominating. In contrast, C31 hopanes 42 occur predominantly as the αβ-stereoisomer. These two observations collectively 43 suggest that isomerisation is not inherited from an original biological precursor (i.e. 44 biohopanoids). Using geohopanoid ββ/(αβ+ββ) indices, we demonstrate that the 45 abundance of αβ-hopanoids is strongly influenced by the acidic environment, and we 46 observe a significant positive correlation between C31 hopane isomerisation and pH 47 (n = 94, r 2 = 0.64, p < 0.001). Crucially, there is no correlation between C31 hopane 48 isomerisation and temperature. We therefore conclude that within peats, αβ-49 hopanoids are acid-catalysed diagenetic products and their occurrence at shallow 50 depths indicates that this isomerisation is rapid. This shows that geohopanoid 51 ββ/(αβ+ββ) indices can be used to reconstruct pH within modern and ancient peat-52 forming environments. However, we only recommend using ββ/(αβ+ββ) indices to 53 interrogate large amplitude (> 1 pH unit) and longer-term (> 1 kyr) variation. Overall, 54 our findings demonstrate the potential of geohopanoids to provide unique new 55 insights into understanding depositional environments and interpreting terrestrial 56 organic matter sources in the geological record. 57 58 Highlights: 59• Peats are characterised by a wide range of geohopanoids 60• C32 hopanoic acids and C31 hopanes usually dominate the geohopanoid 61 assemblage 62• Diagenesis and isomerisation of geohopanoids occurs rapidly 63• Hopane stereochemistry is strongly influenced by the acidic environment 64• Geohopanoids may be a useful proxy for assessing relative changes in pH 65 66

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Section: Introduction 77mentioning

confidence: 99%

Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives

Inglis

Naafs

Zheng

et al. 2018

Geochimica et Cosmochimica Acta

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“…Only bacteria containing the gene encoding for squalene hopane cyclase (sqhC; Ochs et al, 1992) are able to biosynthesis hopanoids. Biosynthesis of BHPs is believed to be limited to < 10% of all bacterial species in most communities (Pearson et al, 2007). The initial step in BHP synthesis is the cyclisation of squalene (controlled via the sqhC gene), with the addition of the hopanoid side chain (via the hpnH gene), leading to the production of 30-(5 0 -adenosyl)hopane (adenosylhopane; 1a; Fig.…”

Section: Introductionmentioning

confidence: 99%

Bacteriohopanepolyols in tropical soils and sediments from the Congo River catchment area

Spencer-Jones

Wagner

Dinga³

et al. 2015

Organic Geochemistry

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a b s t r a c tThe Congo River basin drains the second largest area of tropical rainforest in the world, including a large proportion of pristine wetlands. We present the bacteriohopanepolyol (BHP) inventory of a suite of tropical soils and, from comparison with published data, propose some initial ideas on BHP distribution controls. Strong taxonomic controls on BHP production are evident in wetland sediments. Dominant within the suite were 35-aminobacteriohopane-31,32,33,34-tetrol (aminotetrol) and 35-aminobacterio hopane-30,31,32,33,34-pentol (aminopentol), indicating aerobic methanotrophy. A narrow range and low mean relative abundance of 30-(5 0 -adenosyl)hopane (adenosylhopane) and related compounds, collectively termed ''soil marker" BHPs, were observed in Congo soils (mean 17%, range 7.9-36% of total BHPs, n = 22) compared with literature data from temperate surface soils and Arctic surface soils (mean 36%, range 0-66% of total BHPs, n = 28) suggesting a greater rate of conversion of these BHP precursors to other structures.

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“…Rohmer et al, 1984;Farrimond et al, 1998;Pearson et al, 2007), and likely have the same membrane-ordering role as sterols in eukaryotes (Kannenberg and Poralla, 1999;Sáenz et al, 2012). BHPs are the biological precursors of hopanoids, lipid biomarkers found ubiquitously in the geological record (Ourisson and Albrecht, 1992).…”

Section: Introductionmentioning

confidence: 99%

Anaerobic ammonium-oxidising bacteria: A biological source of the bacteriohopanetetrol stereoisomer in marine sediments

Rush

Damsté

Poulton

et al. 2014

Geochimica et Cosmochimica Acta

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Bacterially-derived bacteriohopanepolyols (BHPs) are abundant, well preserved lipids in modern and paleo-environments. Bacteriohopanetetrol (BHT) is a ubiquitously produced BHP while its less common stereoisomer (BHT isomer) has previously been associated with anoxic environments; however, its biological source remained unknown. We investigated the occurrence of BHPs in Golfo Dulce, an anoxic marine fjord-like enclosure located in Costa Rica. The distribution of BHT isomer in four sediment cores and a surface sediment transect closely followed the distribution of ladderane fatty acids, unique biomarkers for bacteria performing anaerobic ammonium oxidation (anammox). This suggests that BHT isomer and ladderane lipids likely shared the same biological source in Golfo Dulce. This was supported by examining the BHP lipid compositions of two enrichment cultures of a marine anammox species ('Candidatus Scalindua profunda'), which were found to contain both BHT and BHT isomer. Remarkably, the BHT isomer was present in higher relative abundance than BHT. However, a non-marine anammox enrichment contained only BHT, which explains the infrequence of BHT isomer observations in terrestrial settings, and indicates that marine anammox bacteria are likely responsible for at least part of the environmentally-observed marine BHT isomer occurrences.Given the substantially greater residence time of BHPs in sediments, compared to ladderanes, BHT isomer is a potential biomarker for past anammox activity.3

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Novel hopanoid cyclases from the environment

Cited by 116 publications

References 68 publications

Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives

Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives

Bacteriohopanepolyols in tropical soils and sediments from the Congo River catchment area

Anaerobic ammonium-oxidising bacteria: A biological source of the bacteriohopanetetrol stereoisomer in marine sediments

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