Clendinen, C. | Search bioRxiv

bioRxiv2023

Improved characterization of soil organic matter by integrating FTICR-MS, liquid chromatography tandem mass spectrometry and molecular networking: a case study of root litter decay under drought conditions

Knowledge of the type of carbon contained in soils is important for predicting carbon fluxes in a warming climate, yet most soil organic matter (SOM) components are unknown. We used an integrated three-part approach to characterize SOM from decaying root-detritus microcosms subject to either drought or normal conditions. To observe broad differences in SOM compositions we employed direct infusion Fourier transform ion cyclotron resonance mass spectrometry (DI-FTICR-MS). We complemented this with liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify components by library matching. Since libraries contain only a small fraction of SOM components, we also used fragment spectra cosine similarity scores to relate unknowns and library matches through molecular networks. This approach allowed us to corroborate DI-FTICR-MS molecular formulas using library matches and infer structures of unknowns from molecular networks to improve SOM annotation. We found matches to fungal metabolites, and under drought conditions, greater relative amounts of lignin-like vs condensed aromatic polyphenol formulas, and lower average nominal oxidation state of SOM carbon, suggesting reduced decomposition of carbon and/or microbes under stress. We propose this integrated approach as more comprehensive than individual analyses in parallel, with the potential to improve knowledge of the chemical composition and persistence of SOM. SynopsisStructural characterization and identifications are lacking for soil organic matter components. This study integrates molecular formula assignments and structural information from fragment ion spectra into molecular networks to better characterize unknown soil organic matter components. For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=94 SRC="FIGDIR/small/545455v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@140a98org.highwire.dtl.DTLVardef@1c3b26forg.highwire.dtl.DTLVardef@f7b82aorg.highwire.dtl.DTLVardef@15c012f_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2023

Neurophysiological Changes Associated with Vibroacoustically-augmented Breath-focused Mindfulness for Dissociation: Targeting Interoception and Attention

BackgroundDissociative symptoms can emerge after trauma and interfere with attentional control and interoception, both of which are barriers to mind-body interventions such as breath-focused mindfulness (BFM). To overcome these barriers, we tested the use of an exteroceptive augmentation to BFM, using vibrations equivalent to the amplitude of the auditory waveform of the actual breath, delivered via a wearable subwoofer in real time (VBFM). We tested whether this device enhanced interoceptive processes, attentional control and autonomic regulation in trauma-exposed women with dissociative symptoms. Method65 women, majority (82%) Black American, aged 18-65 completed self-report measures of interoception and 6 BFM sessions, during which electrocardiographic recordings were taken to derive high-frequency heart rate variability (HRV) estimates. A subset (n=31) of participants completed functional MRI at pre- and post-intervention, during which they were administered an affective attentional control task. ResultsCompared to those who received BFM only, women who received VBFM demonstrated greater increases in interoception, particularly their ability to trust body signals, increased sustained attention, and as well as increased connectivity between nodes of emotion processing and interoceptive networks. Intervention condition moderated the relationship between interoception change and dissociation change, as well as the relationship between dissociation and HRV change. ConclusionsVibration feedback during breath focus yielded greater improvements in interoception, sustained attention and increased connectivity of emotion processing and interoceptive networks. Augmenting BFM with vibration appears to have considerable effects on interoception, attention and autonomic regulation; it could be used as a monotherapy or to address trauma treatment barriers.

neuroscience↗