ABSTRACT
The heathland lichen Cladonia portentosa was collected from sites in mainland Britain differing either in rates of wet N deposition or in annual mean N concentration in rainfall based on a modelled data set. Methanolic extracts of thalli were analyzed by liquid chromatography time-of-flight mass spectrometry to yield metabolic profiles. Differences between sites in metabolite concentration were quantified using multivariate statistical tools and used to identify potential biomarker molecules. The abundances of three structurally related betaine lipids showed an increase with increasing modelled N deposition to a threshold of 22.3 kg ha(-1) year(-1) after which they remained constant. In contrast, the abundance of a phosphatidylcholine (PC) lipid showed concomitant decrease. Correlations of the identified biomarkers with N deposition and precipitation were stronger than those with N concentrations. The results presented in this study clearly show that N enrichment associated with tissue P limitation changes lipid composition, leading to shifts from PCs to betaine lipids, and that these lipids identified have the potential to be used as biomarkers for nitrogen enrichment.
Subject(s)
Betaine/metabolism , Environmental Monitoring/methods , Lichens/metabolism , Lipotropic Agents/metabolism , Nitrogen/metabolism , Phosphorus/metabolism , Atmosphere/chemistry , Biomarkers/metabolism , Lichens/chemistry , Lipid Metabolism , Molecular Structure , Nitrogen/analysis , Phosphatidylcholines/metabolism , Rain/chemistry , United KingdomABSTRACT
Atmospheric pressure chemical ionisation reversed-phase high-performance liquid chromatography/multistage mass spectrometry has been used to study the mass spectral fragmentation of the cyanobacterial sheath pigment scytonemin and its reduced counterpart. The two pigments exhibit characteristic fragment ions in their MS2 and MS3 spectra that are of value in confirming the identification of the structures in extracts from natural environments.
Subject(s)
Chromatography, High Pressure Liquid/methods , Indoles/chemistry , Phenols/chemistry , Pigments, Biological/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Atmospheric Pressure , Cyanobacteria/chemistry , Indoles/analysis , Phenols/analysis , Pigments, Biological/analysisABSTRACT
Novel transformation products of chlorophyll a incorporating a methyl sulfide group in the substituent at the C-3 position have been identified in Recent sediments from an Antarctic lake.
Subject(s)
Chlorophyll/chemistry , Geologic Sediments/chemistry , Sulfur Compounds/chemistry , Chlorophyll A , Chromatography, High Pressure Liquid/methods , Magnetic Resonance Spectroscopy , Sulfur Compounds/analysisABSTRACT
Atmospheric pressure chemical ionisation liquid chromatography/multi-stage ion trap mass spectrometry (APCI-LC/MS(n)) has been applied to the study of intact bacteriohopanepolyols. Spectral characterisation of bacteriohopanepolyols of known structure present in bacterial extracts (Zymomonas mobilis and a fermenter containing methanotrophs including Methylococcus capsulatus) has revealed greater structural detail than previous liquid chromatography/mass spectrometry (LC/MS) methods and identified characteristic fragmentations indicative of numerous biohopanoid structures. Analysis of a Recent sedimentary extract from Lake Druzhby (Antarctica) has demonstrated the power of this technique to detect biohopanoids in complex samples including at least partial characterisation of previously unknown composite structures.
