Coffinet, S., Meador, T.B., Mühlena, L., Becker, K.W., Schröder, J., Zhu, Q.-Z., Lipp, J.S., Heuer, V.B., Crump, M.P., Hinrichs, K.-U., 2020. Structural elucidation and environmental distributions of butanetriol and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs). Biogeosciences 17, 317-330.

https://www.biogeosciences.net/17/317/2020/ Butanetriol and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs) are membrane lipids, recently Methanomassiliicoccus luminyensis discovered in sedimentary environments and in the methanogenic archaeon . They possess an unusual structure, which challenges fundamental assumptions in lipid biochemistry. Indeed, they bear a butanetriol or a pentanetriol backbone instead of a glycerol at one end of their core structure. In this study, we unambiguously located the additional methyl group of the BDGT compound on the C3 carbon of the lipid backbone via high-field nuclear magnetic resonance (NMR) experiments. We further systematically explored the abundance, distribution and isotopic composition of BDGTs and PDGTs as both intact polar and core lipid forms in marine sediments collected in contrasting environments of the Mediterranean Sea and Black Sea. High proportions of intact polar BDGTs and PDGTs in the deeper methane-laden sedimentary layers and 13 relatively C-depleted BDGTs, especially in the Rhone Delta and in the Black Sea, are in agreement with a probable methanogenic source for these lipids. However, contributions from heterotrophic Archaea to BDGTs (and PDGTs) cannot be excluded, particularly in the eastern Mediterranean Sea, and contrasting BDGT and PDGT headgroup distribution patterns were observed between the different sites studied. This points to additional, non-methanogenic, archaeal sources for these lipids.

Cojoc, L.R., Enache, M.I., Neagu, S.E., Lungulescu, M., Setnescu, R., Ruginescu, R., Gomoiu, I., 2019. Carotenoids produced by halophilic bacterial strains on mural paintings and laboratory conditions. FEMS Microbiology Letters 366, fnz243.

https://doi.org/10.1093/femsle/fnz243 Due to the presence of efflorescences and improper microclimate conditions for conservation, pink-pigmented areas were reported in two historic monuments in Northern and Central part of Romania. The aims of the present study were to find the nature of pink pigments observed on the pictorial layer, original and infilling mortar, to investigate the presence of carotenoids both on mural paintings and in the isolated halophilic bacterial strains and to preliminary characterize and identify the producing strains. Their role in the aesthetical biodeterioration of historic monuments was also pointed out. Obtained Raman spectra of the pink pigments Halobacillus extracted both from the isolated bacterial cultures (molecularly identified as mostly related to hunanensis Halobacillus naozhouensis and ) and from the mural painting samples contain diagnostic bands of carotenoids. These results were confirmed by FTIR spectroscopy. The strong Raman signal of bacterial carotenoids detected on mural painting indicated their potential use as biomarker molecules in the evaluation of contamination and state of conservation of mural paintings and lithic monuments. Our results contribute to opening a new direction in cultural heritage restoration to assess the conservation status on the basis of interdisciplinary research, starting with spectroscopic methods (Raman, FTIR) and confirmed by microbiological analysis.

Colby, silico Colby, silico S.M., Nuñez, J.R., Hodas, N.O., Corley, C.D., Renslow, R.R., 2020. Deep learning to generate chemical property libraries and candidate molecules for small molecule identification in complex samples. Analytical Chemistry 92, 1720-1729.

https://doi.org/10.1021/acs.analchem.9b02348 Comprehensive and unambiguous identification of small molecules in complex samples will revolutionize our understanding of the role of metabolites in biological systems. Existing and emerging technologies have enabled measurement of chemical properties of molecules in complex mixtures and, in concert, are sensitive enough to resolve even stereoisomers. Despite these experimental advances, small molecule identification is inhibited by (i) chemical reference libraries (e.g., mass spectra, collision cross section, and other measurable property libraries) representing <1% of known molecules, limiting the number of possible identifications, and (ii) the lack of a method to generate candidate matches directly from experimental features (i.e., without a