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Marine bacteria contribute substantially to nutrient cycling in the oceans and can engage in close interactions with microalgae. Many microalgae harbor characteristic satellite bacteria, many of which participate in N-acyl homoserine lactone (AHL) mediated quorum sensing. In the diffusion-controlled phycosphere, AHLs can reach high local concentrations, with some of them transforming into tetramic acids, compounds with a broad bioactivity. We tested a representative AHL, N-(3-oxododecanoyl) homoserine lactone, and its tetramic acid rearrangement product on the diatom Phaeodactylum tricornutum. While cell growth and photosynthetic efficiency of photosystem II were barely affected by the AHL, exposure to its tetramic acid rearrangement product had a negative effect on photosynthetic efficiency and led to growth inhibition and cell death in the long term, with a minimum inhibitory concentration between 20 and 50 μΜ. These results strengthen the view that AHLs may play an important role in shaping the outcome of microalgae–bacteria interactions.

Pyrolysis liquids are very complex and heterogeneous in composition. This makes them hard to comprehensively analyze, which is one of the hurdles that could hinder further advances in science and technology toward their valorization. Recently, renewed interest grew for quantitative recording of two-dimensional 1H–13C heteronuclear single-quantum correlation (HSQC) nuclear magnetic resonance (NMR). This makes 1H–13C HSQC NMR a valuable tool to fingerprint and quantitatively assess these complex liquids. However, data analysis of complex 1H–13C HSQC spectra lacks behind on these recent experimental developments. That is, 1H–13C HSQC spectra are often manually and ad hocanalyzed. This work, therefore, seeks to automate data analysis from 1H–13C HSQC spectra. We explored the use of image processing tools and identified their much underestimated potential. Indeed, many of the existing tools (often built-in software) were found to be applicable for noise detection/removal, generation/comparison of regions of interest, etc. Moreover, pseudo-Voigt peaks were fitted to the 1H–13C HSQC spectra, with an average R2of 0.94. These fitted spectral peaks allowed for the generation of a peak list, as an input for multivariate analysis. This allowed for pinpointing differences in the chemical composition of the samples. Overall, a new echelon for easy analysis of 1H–13C HSQC spectra has been explored and demonstrated.