Location of double bonds in monounsaturated fatty acids of Campylobacter cryaerophila with dimethyl disulfide derivatives and combined gas chromatography-mass spectrometry

Moss, C W; Lambert-Fair, Mary Ann

doi:10.1128/jcm.27.7.1467-1470.1989

Cited by 65 publications

(48 citation statements)

References 5 publications

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“…The remaining TLE containing the FAs was then acidified, and the protonated FAs were extracted with hexane and methylated with methanolic BF 3 . Double bond positions were determined through analysis of their dimethyldisulfide adducts (Nichols et al 1986;Moss and Lambert-Fair 1989). Hydrocarbons, ketones, and alcohols were separated over a SiOH glass cartridge.…”

Section: Methodsmentioning

confidence: 99%

Micro‐aerobic bacterial methane oxidation in the chemocline and anoxic water column of deep south‐Alpine Lake Lugano (Switzerland)

Blees

Niemann

Wenk

et al. 2014

Limnology & Oceanography

133

207

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We measured seasonal variations in the vertical distribution of methane concentration, methane oxidation rates, and lipid biomarkers in the northern basin of Lake Lugano. Methane consumption below the oxic-anoxic interface co-occurred with concentration maxima of 13 C-depleted C 16 fatty acid biomarkers (with d 13 C values as low as 270%) in the anoxic water column, as well as characteristic d 13 C CH 4 profiles. We argue that the conspicuous methane concentration gradients are primarily driven by (micro-)aerobic methane oxidation (MOx) below the chemocline. We measured a strong MOx potential throughout the anoxic water column, while MOx rates at in situ O 2 concentration . 10 nmol L 21 were undetectable. Similarly, we found MOx-related biomarkers and gene sequences encoding the particulate methane monooxygenase in the anoxic, but not the oxic, water. The mechanism of (episodic) oxygen supply sustaining the MOx community in anoxic waters is still uncertain. Our results indicate that a bacterial methanotrophic community is responsible for the methane consumption in Lake Lugano, without detectable contribution from archaeal methanotrophs. Bacterial populations that accumulated both at the suboxic-anoxic interface and in the deeper anoxic hypolimnion, where maximum potential MOx rates were observed throughout the year (1.5-2.5 mmol L 21 d 21 ) were mainly related to Methylobacter sp. Close relatives are found in lacustrine environments throughout the world, and their potential to thrive under micro-and anoxic conditions in Lake Lugano may imply that micro-aerobic methane oxidation is important in methane cycling and competition for methane and oxygen in stratified lakes worldwide.

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Section: Methodsmentioning

confidence: 99%

Micro‐aerobic bacterial methane oxidation in the chemocline and anoxic water column of deep south‐Alpine Lake Lugano (Switzerland)

Blees

Niemann

Wenk

et al. 2014

Limnology & Oceanography

133

207

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“…Further separation into a polar lipid-derived fatty acid (FA) and an apolar fraction, as well as derivatization of FAs into fatty acid methyl esters, was carried out according to previous work (Elvert et al 2003;Niemann et al 2005). Double bond positions were determined through analysis of their dimethyl-disulfide adducts (Nichols et al 1986;Moss and Lambert-Fair 1989).…”

Section: Methodsmentioning

confidence: 99%

Bacterial methanotrophs drive the formation of a seasonal anoxic benthic nepheloid layer in an alpine lake

Blees¹,

Niemann²,

Wenk³

et al. 2014

Limnology & Oceanography

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We investigated the formation and microbial composition of a seasonal benthic nepheloid layer (BNL) in the eutrophic, monomictic southern basin of Lake Lugano. During stratification, a BNL developed at the sedimentwater interface and progressively expanded 20-30 m into the water column, following the rising oxic-anoxic interface. The dominance of the fatty acids C 16:1v5 , C 16:1v6 , C 16:1v7 , and C 16:1v8 , with d 13 C values between 262% (v6) and 280% (v7), suggests that the BNL was composed primarily of Type I aerobic methane oxidizing bacteria (MOB). Indeed, MOB contributed . 75% to the fatty acid carbon pool in the fully developed BNL, with cell densities up to 8.5 3 10 5 cells mL 21 . In ex situ incubation experiments, CH 4 turnover rate coefficients were up to 2.1 d 21 , which translates into potential CH 4 oxidation rates as high as 20 mmol m 23 d 21 under in situ CH 4 concentrations. CH 4 oxidation was limited by the diffusive supply of O 2 , and O 2 consumption by aerobic CH 4 oxidation (up to 13.1 mmol m 22 d 21 ) appears to be the primary driver of the seasonal growth of the BNL and expansion of the hypolimnetic anoxic zone. Methanotrophic activity at the interface between oxic and anoxic water masses can actuate the formation of a BNL, which in turn functions as an effective microbial CH 4 filter in the water column, preventing CH 4 transport to surface waters and evasion to the atmosphere. In situ biomass production by methanotrophic bacteria may represent, in addition to sediment resuspension and detritus trapping, a novel BNL formation mechanism.

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“…FAs were methylated with methanolic BF 3 solution yielding FAMEs. Doublebond positions of monounsaturated FAs were determined by the analysis of dimethyl disulphide adducts (Nichols et al, 1986;Moss & Lambertfair, 1989).…”

Section: Fatty Acid Extraction and Preparation Of Derivatesmentioning

confidence: 99%

Field-scale labelling and activity quantification of methane-oxidizing bacteria in a landfill-cover soil

Henneberger

Chiri

Blees

et al. 2012

FEMS Microbiol Ecol

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Editor: Tillmann LuedersKeywords gas push-pull test; stable isotope probing; phospholipid ester-linked fatty acids; methanotrophs; in situ labelling. AbstractAerobic methane-oxidizing bacteria (MOB) play an important role in soils, mitigating emissions of the greenhouse gas methane (CH 4 ) to the atmosphere. Here, we combined stable isotope probing on MOB-specific phospholipid fatty acids (PLFA-SIP) with field-based gas push-pull tests (GPPTs). This novel approach (SIP-GPPT) was tested in a landfill-cover soil at four locations with different MOB activity. Potential oxidation rates derived from regular-and SIP-GPPTs agreed well and ranged from 0.2 to 52.8 mmol CH 4 (L soil air)À1 day À1 . PLFA profiles of soil extracts mainly contained C 14 to C 18 fatty acids (FAs), with a dominance of C 16 FAs. Uptake of 13 C into MOB biomass during SIP-GPPTs was clearly indicated by increased d13 C values (up to c. 1500&) of MOB-characteristic FAs. In addition, 13 C incorporation increased with CH 4 oxidation rates. In general, FAs C 14:0 , C 16:1x8 , C 16:1x7 and C 16:1x6 (type I MOB) showed highest 13 C incorporation, while substantial 13 C incorporation into FAs C 18:1x8 and C 18:1x7 (type II MOB) was only observed at highactivity locations. Our findings demonstrate the applicability of the SIP-GPPT approach for in situ quantification of potential CH 4 oxidation rates and simultaneous labelling of active MOB, suggesting a dominance of type I MOB over type II MOB in the CH 4 -oxidizing community in this landfill-cover soil.

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Location of double bonds in monounsaturated fatty acids of Campylobacter cryaerophila with dimethyl disulfide derivatives and combined gas chromatography-mass spectrometry

Cited by 65 publications

References 5 publications

Micro‐aerobic bacterial methane oxidation in the chemocline and anoxic water column of deep south‐Alpine Lake Lugano (Switzerland)

Micro‐aerobic bacterial methane oxidation in the chemocline and anoxic water column of deep south‐Alpine Lake Lugano (Switzerland)

Bacterial methanotrophs drive the formation of a seasonal anoxic benthic nepheloid layer in an alpine lake

Field-scale labelling and activity quantification of methane-oxidizing bacteria in a landfill-cover soil

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