Visible light-induced oxidation of lipid components of purple sulfur bacteria: a significant process in microbial mats

Marchand, Daphné; Rontani, Jean‐François

doi:10.1016/s0146-6380(02)00192-4

Cited by 44 publications

(19 citation statements)

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“…NaBH 4 reduction of these oxoacids then afforded the corresponding ( -1)-and ( -2)-hydroxycarboxylic acids. 8-Hydroxyoctadec-9-enoic, 10-hydroxyoctadec-11-enoic, 10-hydroxyoctadecanoic, 11-hydroxyoctadecanoic, 12-hydroxyoctadecanoic, 9-oxooctadecanoic, 10-oxooctadecanoic, and 9-oxooctadec-10-enoic acids were prepared according to previously described procedures [22]. 9-Oxodecanoic acid resulted from hydration and retro-aldolization (alkaline hydrolysis) of 9-oxooctadec-10-enoic acid.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Rontani

Aubert²

2008

J. Am. Soc. Mass Spectrom.

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This paper, describing electron ionization mass spectral fragmentation of some hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives, focuses on the formation of fragment ions resulting from the interactions between the two functionalities of these compounds. These interactions result in the formation of fragment ions at [CH 2 ilylation is by far the major derivatization procedure for GC/MS analyses [1][2][3]. Silyl derivatives are formed when active proton displacement (in ϪOH, ϪSH, or ϪNH groups) by an alkylsilyl group occurs. The most common silylation procedure is trimethylsilylation. Trimethylsilyl derivatives combine thermal stability and high volatility. In general, electron ionization (EI) mass spectra of trimethylsilyl ethers or esters exhibit a significant [M Ϫ 15] ϩ ion formed by loss of a methyl group bonded to silicon, which is very useful in determining the molecular mass. It is very important to note that EI mass spectra of trimethylsilyl derivatives may be employed not only for molecular weight determinations, but also for structural deductions [4].Trimethylsilyl group migrations during EI fragmentation process are common [5,6] and take place by means of ion-neutral complexes [7]. These rearrangements are generally considered useful for deducing structures of unknown spectra [8]; however, in some cases, misleading conclusions may be drawn. Though trimethylsilyl group migrations usually occur through five-to eight-member-ring transition states [9], intense long-range migration of the trimethylsilyl group was previously observed in the case of trimethylsilyl derivatives of some steroid compounds [8, 10 -13]. The capability of the trimethylsilyl group to migrate over a wide range of distances was also demonstrated in the case of semirigid or rigid molecules [5]. Recently, a significant transfer of trimethylsilyl group towards the carbonyl group was also observed during EI fragmentation of the trimethylsilyl derivatives of long-chain -hydroxycarboxylic and -dicarboxylic acids [14], showing that such migrations may also occur in the case of nonrigid structures.Hydrogen transfers between distant functionalities during EI fragmentation processes are also well known [6,15,16], for this reaction hydrogen activation is needed and is caused by groups such as keto, amino, ether, trimethylsilyloxy, as well as by chain branching and unsaturation.In the present work, which is a part of a more general study of the synergistic effects during EI mass fragmentation of polyfunctional compounds [14,[17][18][19], we describe EI mass spectral fragmentation of several hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives, which involves trimethylsilyl and hydrogen transfers.The characterization of such compounds appears to be of great environmental importance [20,21]. Indeed, it was previously demonstrated that autoxidative processes could induce a bias during alkenone-based paAddress reprint requests to Dr.

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Section: Methodsmentioning

confidence: 99%

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Rontani

Aubert²

2008

J. Am. Soc. Mass Spectrom.

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“…Comparison of the amounts of alcohols present after acetylation and after NaBD 4 reduction made it possible to estimate the proportion of hydroperoxides and alcohols present in the samples, while after NaBD 4 -reduction deuterium labelling allowed to estimate the proportion of ketones really present in the samples (Marchand and Rontani, 2003). Acetylation was carried out in 300 µl of a mixture of pyridine and acetic anhydride (2 : 1, v/v), allowed to react at 50 • C overnight and then evaporated to dryness under nitrogen.…”

Section: Biogeosciencesmentioning

confidence: 99%

Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean)

et al. 2012

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Abstract. The lipid content of seven samples of sinking particles collected with sediment traps moored at ∼ 100 m depth in summer and fall across the Canadian Beaufort Shelf (Arctic Ocean) was investigated. Our main goal was to quantify and characterize the biotic and abiotic degradation processes that acted on sinking material during these periods. Diatoms, which dominated the phytoplanktonic assemblage in every trap sample, appeared to be remarkably sensitive to Type II (i.e. involving singlet oxygen) photodegradation processes in summer, but seemed to be relatively unaffected by biotic degradation at the same time. Hence, the relative recalcitrance of phytodetritus towards biodegradation processes during the Arctic midnight sun period was attributed to the strong photodegradation state of heterotrophic bacteria, which likely resulted from the efficient transfer of singlet oxygen from photodegraded phytoplanktonic cells to attached bacteria. In addition, the detection in trap samples of photoproducts specific to wax ester components found in herbivorous copepods demonstrated that zooplanktonic faecal material exported out of the euphotic zone in summer were affected by Type II photodegradation processes as well. By contrast, sinking particles collected during the autumn were not influenced by any light-driven stress. Further chemical analyses showed that photodegraded sinking particles contained an important amount of intact hydroperoxides, which could then induce a strong oxidative stress in underlying sediments.

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“…Taranto et al, 2003) and as lipid oxidation products (e.g. el-Sharkawy et al, 1992; Marchand & Rontani, 2003). The IPLs were dominated by diacylglyceride (DAG) and sphingolipid (ceramide) core lipid structures with monoglycosidic, mixed phosphomonoglycosidic and fatty-acid-modified monoglycosidic polar head groups (one additional fatty acid attached to the sugar) (Fig.…”

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confidence: 99%

Pelolinea submarina gen. nov., sp. nov., an anaerobic, filamentous bacterium of the phylum Chloroflexi isolated from subseafloor sediment

Imachi

Sakai

Lipp

et al. 2014

International Journal of Systematic and Evolutionary Microbiology

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Pelolinea submarina gen. nov., sp. nov., an anaerobic, filamentous bacterium of the phylum Chloroflexi isolated from subseafloor sediment , was isolated from a methanogenic community, which was originally established from subseafloor sediments collected from off the Shimokita Peninsula, Japan. Cells were non-spore-forming, non-motile, Gram-stain-negative and filamentous. The filaments were longer than 10 mm and 130-150 nm in width. Growth of the strain was observed at 10-37 6C (optimum 25-30 6C), at pH 5.5-8.5 (optimum pH 7.0) and in 0-50 g NaCl l "1 (optimum 15 g NaCl l "1 ). The strain was able to grow with a number of carbohydrates in the presence of yeast extract. The major cellular fatty acids were monounsaturated C 18 : 1 v9, C 16 : 1 v7 and saturated C 18 : 0 and C 16 : 0 . The intact polar lipids of the strain were dominated by diacylglyceride and sphingolipid core lipid structures with monoglycosidic, mixed phosphomonoglycosidic and fatty-acid-modified monoglycosidic polar head groups. The G+C content of the genomic DNA was 52.4 mol%. Based on the comparative 16S rRNA gene sequence analysis, strain MO-CFX1T was affiliated with the class Anaerolineae within the phylum Chloroflexi and was most closely related to Leptolinea tardivitalis YMTK-2 T (sequence identity of 91.0 %). Based on phenotypic and genetic properties of the novel isolate, we propose a novel species representing a new genus Pelolinea submarina gen. nov., sp. nov., for strain MO-CFX1 T (5JCM 17238 T ,5KCTC 5975 T ). This is the first formal description, to our knowledge, of an isolate of the phylum Chloroflexi from the deep-sea sedimentary environment.Culture-independent molecular studies based on a survey of PCR-amplified 16S rRNA genes have revealed members of the bacterial phylum Chloroflexi to be one of the dominant bacterial components in subseafloor sedimentary environments (Blazejak & Schippers, 2010;Fry et al., 2008;Inagaki et al., 2006;Inagaki & Nakagawa, 2008;Teske, 2013;Yamada & Sekiguchi, 2009). Most of the 16S rRNA gene sequences of members of the phylum Chloroflexi belong to members of the classes Anaerolineae, Caldilineae and Dehalococcoidia. These findings strongly indicate that members of the phylum Chloroflexi play an important role in biogeochemical cycles in the marine subsurface environment. However, until now, cultured representatives from these environments have not been available and their detailed physiological, genetic and ecological properties are currently not well understood.Recently, we have successfully isolated micro-organisms of the class Anaerolineae, designated strains MO-CFX1 T and MO-CFX2, from marine subsurface sediments collected from off the Shimokita Peninsula of Japan in the northwestern Pacific Ocean (Site C9001, 1180 m water depth) (Imachi et al., 2011). Enrichment and isolation of these strains were achieved using a continuous-flow bioreactor Abbreviations: BSTFA, N,O-Bis(trimethylsilyl)trifluoroacetamide; FAME, fatty acid methyl ester; IPL, intact polar lipid; TLE, total lipid extract.

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Visible light-induced oxidation of lipid components of purple sulfur bacteria: a significant process in microbial mats

Cited by 44 publications

References 45 publications

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean)

Pelolinea submarina gen. nov., sp. nov., an anaerobic, filamentous bacterium of the phylum Chloroflexi isolated from subseafloor sediment

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