scholarly journals Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

2013 ◽  
Vol 9 ◽  
pp. 942-950 ◽  
Author(s):  
Nelson L Brock ◽  
Christian A Citron ◽  
Claudia Zell ◽  
Martine Berger ◽  
Irene Wagner-Döbler ◽  
...  

Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP) via competing pathways releasing either methanethiol (MeSH) or dimethyl sulfide (DMS). Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP) were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextraction coupled to GC–MS. Feeding experiments with [2H6]DMSP resulted in the incorporation of a deuterium label into MeSH and DMS. Knockout of relevant genes from the known DMSP demethylation pathway to MeSH showed in both species a residual production of [2H3]MeSH, suggesting that a second demethylation pathway is active. The role of DMSP degradation pathways for MeSH and DMS formation was further investigated by using the synthetic analogue DMTeP as a probe in feeding experiments with the wild-type strain and knockout mutants. Feeding of DMTeP to the R. pomeroyi knockout mutant resulted in a diminished, but not abolished production of demethylation pathway products. These results further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO4 2−, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable sulfur source for the MeSH volatiles, whereas incorporation of labeling from sulfate was not observed. Moreover, the utilization of selenite and selenate salts by marine alphaproteobacteria for the production of methylated selenium volatiles was explored and resulted in the production of numerous methaneselenol-derived volatiles via reduction and methylation. The pathway of selenate/selenite reduction, however, proved to be strictly separated from sulfate reduction.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huimin Zhang ◽  
Hongguang Yan ◽  
Quan Li ◽  
Hui Lin ◽  
Xiaopeng Wen

AbstractThe floral fragrance of plants is an important indicator in their evaluation. The aroma of sweet cherry flowers is mainly derived from their essential oil. In this study, based on the results of a single-factor experiment, a Box–Behnken design was adopted for ultrasound- and microwave-assisted extraction of essential oil from sweet cherry flowers of the Brooks cultivar. With the objective of extracting the maximum essential oil yield (w/w), the optimal extraction process conditions were a liquid–solid ratio of 52 mL g−1, an extraction time of 27 min, and a microwave power of 435 W. The essential oil yield was 1.23%, which was close to the theoretical prediction. The volatile organic compounds (VOCs) of the sweet cherry flowers of four cultivars (Brooks, Black Pearl, Tieton and Summit) were identified via headspace solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). The results showed that a total of 155 VOCs were identified and classified in the essential oil from sweet cherry flowers of four cultivars, 65 of which were shared among the cultivars. The highest contents of VOCs were aldehydes, alcohols, ketones and esters. Ethanol, linalool, lilac alcohol, acetaldehyde, (E)-2-hexenal, benzaldehyde and dimethyl sulfide were the major volatiles, which were mainly responsible for the characteristic aroma of sweet cherry flowers. It was concluded that the VOCs of sweet cherry flowers were qualitatively similar; however, relative content differences were observed in the four cultivars. This study provides a theoretical basis for the metabolism and regulation of the VOCs of sweet cherry flowers.


2017 ◽  
Vol 17 (14) ◽  
pp. 8903-8922 ◽  
Author(s):  
Yang Yang ◽  
Hailong Wang ◽  
Steven J. Smith ◽  
Richard Easter ◽  
Po-Lun Ma ◽  
...  

Abstract. The global source–receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF) from 16 regions/sectors for years 2010–2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM) with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is −0.42 W m−2, with −0.31 W m−2 contributed by anthropogenic sulfate and −0.11 W m−2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes 17–84 % to the total DRF. East Asia has the largest contribution of 20–30 % over the Northern Hemisphere mid- and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of −0.44 W m−2. DMS has the largest contribution, explaining −0.23 W m−2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.


Author(s):  
I. V. Yakovleva ◽  
E. A. Kurbatova ◽  
E. A. Akhmatova ◽  
E. V. Sukhova ◽  
D. V. Yashunsky ◽  
...  

Aim. Production of monoclonal antibodies (mAb) to synthetic tetrasaccharide - repeating unit of the capsular polysaccharide (CP) of Streptococcus pneumoniae serotype 14 and their immunochemical characterization. Materials and methods. In order to generate the hybridoma producing mAb, mice were immunized with synthetic tetrasaccharide conjugated with bovine serum albumin (BSA) with following hybridization of B lymphocytes with mouse myeloma cells. Antibodies were obtained in vitro andin vivo. Immunochemical characterization of mAb to tetrasaccharide was carried out using a variety of ELISA options. Results. For the first time obtained mouse hybridoma, producing IgM to tetrasacchride. The IgM titer of anti-tetrasacharide antibodies in supernatants of clones and in the ascitic fluid of mice in ELISA detected by biotinylated tetrasaccharide and synthetic CP adsorbed on the solid phase was higher compared to the use of bacterial CP as well cover antigen. In the reaction of inhibition of the ELISA, the mAb recognized the corresponding carbohydrate epitopes of the bacterial CP of S. pneumoniae serotype 14 dissolved in the liquid phase better than tetrasaccharide ligand and synthetic CP. Conclusion. To detect mAb to tetrasaccharide in ELISA preferably to use synthetic analogues of the CP as solid phase antigens. The obtained mAb to tetrasaccharide can be used to determine the representation of the protective tetrasaccharide epitope of CP in the development of pneumococcal vaccines.


2012 ◽  
Vol 79 (4) ◽  
pp. 1200-1211 ◽  
Author(s):  
Agnès Hébert ◽  
Marie-Pierre Forquin-Gomez ◽  
Aurélie Roux ◽  
Julie Aubert ◽  
Christophe Junot ◽  
...  

ABSTRACTYarrowia lipolytica, located at the frontier of hemiascomycetous yeasts and fungi, is an excellent candidate for studies of metabolism evolution. This yeast, widely recognized for its technological applications, in particular produces volatile sulfur compounds (VSCs) that fully contribute to the flavor of smear cheese. We report here a relevant global vision of sulfur metabolism inY. lipolyticabased on a comparison between high- and low-sulfur source supplies (sulfate, methionine, or cystine) by combined approaches (transcriptomics, metabolite profiling, and VSC analysis). The strongest repression of the sulfate assimilation pathway was observed in the case of high methionine supply, together with a large accumulation of sulfur intermediates. A high sulfate supply seems to provoke considerable cellular stress via sulfite production, resulting in a decrease of the availability of the glutathione pathway's sulfur intermediates. The most limited effect was observed for the cystine supply, suggesting that the intracellular cysteine level is more controlled than that of methionine and sulfate. Using a combination of metabolomic profiling and genetic experiments, we revealed taurine and hypotaurine metabolism in yeast for the first time. On the basis of a phylogenetic study, we then demonstrated that this pathway was lost by some of the hemiascomycetous yeasts during evolution.


2015 ◽  
Vol 53 (3) ◽  
pp. 1009-1011 ◽  
Author(s):  
Timothy J. J. Inglis ◽  
Dorothee R. Hahne ◽  
Adam J. Merritt ◽  
Michael W. Clarke

Solid-phase microextraction gas chromatography-mass spectrometry (SPME-GCMS) was used to show that dimethyl sulfide produced byBurkholderia pseudomalleiis responsible for its unusual truffle-like smell and distinguishes the species fromBurkholderia thailandensis. SPME-GCMS can be safely used to detect dimethyl sulfide produced by agar-grownB. pseudomallei.


Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 842 ◽  
Author(s):  
Igor Jerković ◽  
Marina Kranjac ◽  
Zvonimir Marijanović ◽  
Bojan Šarkanj ◽  
Ana-Marija Cikoš ◽  
...  

The focus of present study is on Codium bursa collected from the Adriatic Sea. C. bursa volatiles were identified by gas chromatography and mass spectrometry (GC-FID; GC-MS) after headspace solid-phase microextraction (HS-SPME), hydrodistillation (HD), and supercritical CO2 extraction (SC-CO2). The headspace composition of dried (HS-D) and fresh (HS-F) C. bursa was remarkably different. Dimethyl sulfide, the major HS-F compound was present in HS-D only as a minor constituent and heptadecane percentage was raised in HS-D. The distillate of fresh C. bursa contained heptadecane and docosane among the major compounds. After air-drying, a significantly different composition of the volatile oil was obtained with (E)-phytol as the predominant compound. It was also found in SC-CO2 extract of freeze-dried C. bursa (FD-CB) as the major constituent. Loliolide (3.51%) was only identified in SC-CO2 extract. Fatty acids were determined from FD-CB after derivatisation as methyl esters by GC-FID. The most dominant acids were palmitic (25.4%), oleic (36.5%), linoleic (11.6%), and stearic (9.0%). FD-CB H2O extract exhibited better antifungal effects against Fusarium spp., while dimethyl sulfoxide (DMSO) extract was better for the inhibition of Penicillium expansum, Aspergillus flavus, and Rhizophus spp. The extracts showed relatively good antifungal activity, especially against P. expansum (for DMSO extract MIC50 was at 50 µg/mL).


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Thomas M. Deere ◽  
Divya Prakash ◽  
Faith H. Lessner ◽  
Evert C. Duin ◽  
Daniel J. Lessner

Abstract Background The production of methane by methanogens is dependent on numerous iron-sulfur (Fe-S) cluster proteins; yet, the machinery involved in Fe-S cluster biogenesis in methanogens remains largely unknown. Methanogen genomes encode uncharacterized homologs of the core components of the ISC (IscS and IscU) and SUF (SufBC) Fe-S cluster biogenesis systems found in bacteria and eukaryotes. Methanosarcina acetivorans contains three iscSU and two sufCB gene clusters. Here, we report genetic and biochemical characterization of M. acetivorans iscSU2. Results Purified IscS2 exhibited pyridoxal 5′- phosphate-dependent release of sulfur from L-cysteine. Incubation of purified IscU2 with IscS2, cysteine, and iron (Fe2+) resulted in the formation of [4Fe-4S] clusters in IscU2. IscU2 transferred a [4Fe-4S] cluster to purified M. acetivorans apo-aconitase. IscU2 also restored the aconitase activity in air-exposed M. acetivorans cell lysate. These biochemical results demonstrate that IscS2 is a cysteine desulfurase and that IscU2 is a Fe-S cluster scaffold. M. acetivorans strain DJL60 deleted of iscSU2 was generated to ascertain the in vivo importance of IscSU2. Strain DJL60 had Fe-S cluster content and growth similar to the parent strain but lower cysteine desulfurase activity. Strain DJL60 also had lower intracellular persulfide content compared to the parent strain when cysteine was an exogenous sulfur source, linking IscSU2 to sulfur metabolism. Conclusions This study establishes that M. acetivorans contains functional IscS and IscU, the core components of the ISC Fe-S cluster biogenesis system and provides the first evidence that ISC operates in methanogens.


2021 ◽  
Vol 17 ◽  
pp. 569-580
Author(s):  
Anuj Kumar Chhalodia ◽  
Jeroen S Dickschat

Two analogues of 3-(dimethylsulfonio)propanoate (DMSP), 3-(diallylsulfonio)propanoate (DAllSP), and 3-(allylmethylsulfonio)propanoate (AllMSP), were synthesized and fed to marine bacteria from the Roseobacter clade. These bacteria are able to degrade DMSP into dimethyl sulfide and methanethiol. The DMSP analogues were also degraded, resulting in the release of allylated sulfur volatiles known from garlic. For unknown compounds, structural suggestions were made based on their mass spectrometric fragmentation pattern and confirmed by the synthesis of reference compounds. The results of the feeding experiments allowed to conclude on the substrate tolerance of DMSP degrading enzymes in marine bacteria.


1985 ◽  
Vol 40 (1-2) ◽  
pp. 29-33 ◽  
Author(s):  
Reinhard Steinkamp ◽  
Heinz Rennenberg

When γ-glutamyltranspeptidase activity in tobacco cells was measured using the artificial substrate γ-glutamyl-p-nitroanilide, liberation of p-nitroaniline was not reduced, but stimulated by addition of glutathione. Therefore, glutathione was not acting as a donator, but as an acceptor of γ-glutamyl moieties in the assay mixture, suggesting that γ-glutamvltranspeptidase is not participating in degradation of glutathione. Feeding experiments with [35S-cys]glutathione sup­ported this conclusion. When tobacco cells were supplied with this peptide as sole sulfur source, glutathione and γ-glutamylcysteine were the only labelled compounds found inside the cells. The low rate of uptake of glutathione apparently prevented the accumulation of measurable amounts of radioactivity in the cysteine pool. A γ-glutamylcyclotransferase, responsible for the conversion of γ-glutamylcysteine to 5-oxo-proline and cysteine was found in ammonium sulfate precipitates of tobacco cell homogenates. The enzyme showed high activities with γ-glutamylmethionine and γ-glutamylcysteine, but not with other γ-glutamyldipeptides or glutathione. From these and previously published experiments [(Rennenberg et a!., Z. Naturforsch. 35c, 708-711 (1980)], it is concluded that glutathione is degraded in tobacco cells via the following pathway: γ-glu-cys-gly → γ-glu-cys → 5-oxo-proline → glu.


1987 ◽  
Author(s):  
K A Bauer ◽  
B L Kass ◽  
M Bednarek ◽  
M Kloczewiak ◽  
J Hawiger ◽  
...  

The activation of factor X by factor VII/VIIa-tissue factor or factor IXa plays a pivotal role in the hemostatic mechanism. This reaction results in the liberation of a peptide from the zymogen for which we have developed a sensitive and specific radioimmunoassay (RIA), The native peptide was purified from activated human factor X by hydroxylapatite chromatography and reverse-phase high pressure liquid chromatography (HPLC). Gel filtration experiments demonstrated that the peptide was not physically associated with the enzyme. A 15 amino acid peptide with the COOH-terminal sequence of the activation fragment was synthesized using the solid-phase method of Merrifield. Antisera were raised in rabbits to the synthetic analogue coupled to bovine serum albumin with glutaraldehyde. The antibody population obtained was used to construct a double antibody RIA and was able to measure as little as 0.02 nM of this component. The antibody reactivity toward the factor X zymogen was negligible (less than 1/36,000 that of the activation peptide on a molar basis). However because other plasma constituents contributed to a nonspecific basal signal in the RIA, we developed an extraction procedure for the native peptide utilizing perchloric acid. Plasma peptide levels in normal individuals were ∼0.1 nM, and elevations up to 0.8 nM were observed in patients with evidence of disseminated intravascular coagulation. Individuals chronically anticoagulated with coumarin derivatives had plasma levels of this peptide suppressed to ∼0.02 nM. The validity of our measurements of factor X activation in vivo is supported by the fact that the immunoreactive signal migrates on reverse-phase HPLC in a manner identical to that of the native activation peptide and can be quantitatively recovered. This assay should be useful for studying the pathophysiology of thrombotic as well as bleeding disorders in humans.


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