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Over the decades our understanding of lichens has shifted to the fact that they are multiorganismic, symbiotic microecosystems, with their complex interactions coming to the fore due to recent advances in microbiomics. Here, we present a mutualistic-parasitic continuum dynamics scenario between an orange lichen and a lichenicolous fungus from the Atacama Desert leading to the decay of the lichen's photobiont and leaving behind a black lichen thallus. Based on isolation, sequencing, and ecophysiological approaches including metabolic screenings of the symbionts, we depict consequences upon infection with the lichenicolous fungus. This spans from a loss of the lichen's photosynthetic activity and an increased roughness of its surface to an inhibition of the parietin synthesis as a shared pathway between the photobiont and the mycobiont, including a shift of secondary metabolism products. This degree of relations has rarely been documented before, although lichenicolous fungi have been studied for over 200 years, adding an additional level to the view of interactions within lichens. [ABSTRACT FROM AUTHOR]

Elucidating molecular-chemical changes that the soil organic N (SON) pool has undergone following long-term cultivation remains a challenge. Our objective was to examine SON compounds in paired native and long-term cultivated soils using three independent analytical methods. Curie-point pyrolysis-gas chromatography/mass spectrometry revealed approximately 60 different organic N-containing molecules of which 11, 13, and 14 were less and 8, 16, and 11 more abundant in the cultivated than in the native soils from Lethbridge, Macklin, and St. Denis, respectively. Pyrolysis-field ionization mass spectrometry (PyFIMS) revealed that heterocyclic N compounds such as substituted pyrroles and pyridines contributed to the overall cultivation-induced changes. Furthermore, Py-FIMS showed that cultivated sites preferentially lost thermally labile peptides and, to a lesser extent, other labile N-containing compounds. The magnitude of losses decreased in the order Lethbridge (80 yr cultivation) > Macklin (85 yr cultivation) > St. Denis (57+ yr cultivation). Relative gains in thermally stable N-containing compounds (all sites) and peptides (Macklin only) followed the same order. The weaker cultivation effect at St. Denis probably reflects a greater inherent stability of SON compounds in the native soil, as indicated by onsets and peaks in the thermal volatilization curves at 40 K higher pyrolysis temperature. Synchrotron-based N K-edge x-ray near-edge fine structure spectroscopy confirmed the enrichment of nitriles and N-heterocycles in the cultivated Lethbridge soil at the expense of amide N. Our multimethodological approach provided evidence for the enrichment of a relatively stable nonproteinaceous pool of SON on cultivation. Abbreviations: Cp Py-GC/MS, Curie-point pyrolysis-gas chromatography/mass spectrometry; NMR, nuclear magnetic resonance; Py-FIMS, pyrolysis-field ionization mass spectrometry; SOC, soil organic carbon; SOM, soil organic matter; SON, soil organic nitrogen; TII, total ion intensity; XANES, x-ray absorption near-edge fine structure.

Fast pyrolysis of chicken manure produced the following three fractions: bio-oil Fraction I, bio-oil Fraction II, and a char. In a previous investigation we analyzed each of the four materials by curie-point pyrolysis-gas chromatography/mass spectrometry (CpPy-FDMS). The objective of this article is to report on the analyses of the same chicken manure and the three fractions derived from it by fast pyrolysis. We now used pyrolysis-field ionization mass spectrometry (Py-FIMS) to characterize the three fractions. In addition, the two bio-oil materials were analyzed by pyrolysis-field desorption mass spectrometry (Py-FDMS). The use of both Py-FIMS and Py-FDMS produced signals over significantly wider mass ranges than did CpPy-GC/MS, and so allowed us to identify considerably larger numbers of constituents in each material. Individual compounds identified in the mass spectra were classified into the following twelve compound classes: (a) low molecular weight compounds (< m/z 62); (b) carbohydrates; (c) phenols + lignin monomers; (d) lignin dimers; (e) n-alkylbenzenes; (f) N-heterocyclics; (g) n-fatty acids; (h) n-alkanes; (i) alkenes; (j) sterols; (k) n-diols and (l) high molecular weight compounds (> m/z 562). Of special interest were the high abundances of low-molecular weight compounds in the two bio-oils which constituted close to one half of the two bio-oils. Prominent among these compounds were water, ammonia, acetic acid, acetamide, propyl radical, formamide and hydrogen cyanide. The main quantitative differences between the two bio-oils was that bio-oil Fraction I, as analyzed by the two mass spectrometric methods, contained lower concentrations of low-molecular weight compounds, carbohydrates, and N-heterocyclics than bio-oil Fraction II but was richer in lignin dimers, n-alkylbenzenes and aliphatics (n-fatty acids, n-alkanes, alkenes, and n-diols). Of special interest were the N-heterocyclics in the two bio-oils such as pyrazole, pyrazoline, substituted pyrroles, pyridine and substituted pyridines, substituted methoxazole, substituted pyrazines, indole and substituted indoles. Fatty acids in all four materials ranged from n-C9 to n-C33, alkanes from n-C9 to n-C40, alkenes from C10:1 to C40:1 and diols from n-C7 to n-C29. The chicken manure, bio-oil Fraction I, and char each contained about 4% sterols with cholesterol, ethylcholestriene, ergosterol, ethylcholestene, ethylcholesterol and β -sitosterol as major components. Semi-quantitative estimates of the total materials identified by Py-FIMS were: chicken manure: 61.1%; bio-oil Fraction I: 81.3%; bio-oil Fraction II: 78.6%; char: 61.3%; and by Py-FDMS were: bio-oil Fraction I: 65.4%; bio-oil Fraction II: 70.0%. [ABSTRACT FROM AUTHOR]