131 research outputs found
Carbon isotope excursions during the late Miocene recorded by lipids of marine Thaumarchaeota, Piedmont Basin, Mediterranean Sea
The response of water column and sedimentary environments to the advent of the Messinian salinity crisis: insights from an onshore deepwater section (Govone, NW Italy)
From biogenic silica and organic matter to authigenic clays and dolomite: Insights from Messinian (upper Miocene) sediments of the Northern Mediterranean
U-pb dating and geochemical constraints to Early Cretaceous hydrothermal dolomitization in the Provençal domain (Maritime alps, NW Italy-SE France)
The bacteriohopanepolyol inventory of novel aerobic methane oxidising bacteria reveals new biomarker signatures of aerobic methanotrophy in marine systems
Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH4) released into the environment. AMO acts as a sink of CH4, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MCBHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO
Avaliação cronológica da variação no volume globular sanguÃneo de bovinos leiteiros
Weight gain and control of endo- and ectoparasites of beef heifers treated with allopathic, herbal and homeopathic drugs
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