In plaque-mass spectrometry imaging of a bloom-forming alga during viral infection reveals a metabolic shift towards odd-chain fatty acid lipids

Abstract

Tapping into the metabolic cross-talk between a host and its virus can reveal unique strategies employed during infection. Viral infection is a dynamic process that generates an evolving metabolic landscape. Gaining a continuous view into the infection process is highly challenging and is limited by current metabolomics approaches, which typically measure the average of the entire population at various stages of infection. Here, we took an innovative approach to study the metabolic basis of host-virus interactions between the bloom-forming alga Emiliania huxleyi and its specific virus. We combined a classical method in virology, the plaque assay, with advanced mass spectrometry imaging (MSI), an approach we termed ‘in plaque-MSI’. Taking advantage of the spatial characteristics of the plaque, we mapped the metabolic landscape induced during infection in a high spatiotemporal resolution, unfolding the infection process in a continuous manner. Further unsupervised spatially-aware clustering, combined with known lipid biomarkers, revealed a systematic metabolic shift during infection towards lipids containing the odd-chain fatty acid pentadecanoic acid (C15:0). Applying ‘in plaque-MSI’ might facilitate the discovery of bioactive compounds that mediate the chemical arms race of host-virus interactions in diverse model systems.

Tracking infection dynamics at single-cell level reveals highly resolved expression programs of a large virus infecting algal blooms

“…The viral strain EhV201 ( 28 ) was propagated on CCMP2090 culture until the culture lysed to clearance, and viral lysate was filtered using 0.45-μm PVDF Stericup-HV vacuum filtration system (Merck). We used the plaque assay as previously described ( 29 ) to quantify infectious virions, and filtered viral lysate generally contained ~10 8 infectious virions per ml. Cultures at the exponential phase (~10 6 cells ml −1 ) were used for viral infection at a high multiplicity of infection (5 infectious virions to 1 cell) at 2 h after the light cycle began.…”

Single Cell Metabolomics: A Future Tool to Unmask Cellular Heterogeneity and Virus-Host Interaction in Context of Emerging Viral Diseases

“…Turkey gut microbiome has been introspected using MALDI-MS platform operated in positive ion mode with nanoparticle microarray and organic matrices . Metabolomics variability during virus host interaction in bloom-forming alga Emiliania huxleyi has been evaluated by Plaque assay combined with several MSI techniques (Flowprobe-MSI, MALDI-MSI, UPLC-q-TOF MS, and LC-MS/MC for lipidomics, GC-MS for fatty acid methyl esters) (Schleyer et al, 2019). Fluorescence in situ hybridization (FISH) microscopy combined with high-resolution atmospheric pressure-MALDI-MSI of Bathymodiolus puteoserpensis epithelial cells has also been used to understand host-microbe symbiosis (Geier et al, 2019).…”

The Polar Lipidome of Cultured Emiliania huxleyi: A Source of Bioactive Lipids with Relevance for Biotechnological Applications

“…To date, the published work on the lipidome of E. huxleyi with characterization at the molecular level was focused on the changes in metabolism associated with viral infections, since the annual collapse of massive of blooms of E. huxleyi has been linked to viral control in the marine environment [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. In addition, one of these studies evaluated the susceptibility to viral infection of diploid (2N) and haploid (1N) cells [ 21 ], since E. huxleyi has a biphasic life cycle consisting of diploid cells that produce coccoliths and uncalcified haploid cells.…”

“…In addition, one of these studies evaluated the susceptibility to viral infection of diploid (2N) and haploid (1N) cells [ 21 ], since E. huxleyi has a biphasic life cycle consisting of diploid cells that produce coccoliths and uncalcified haploid cells. These studies were performed using liquid chromatography–mass spectrometry (LC–MS) with a reversed-phase C8 column [ 15 , 16 , 18 , 21 , 22 ], or a silica column with a diol function on C-chains [ 14 , 17 , 19 , 20 , 21 ]. Of all the lipid species identified, some studies only presented those that underwent significant changes after infection with the virus [ 18 ], or identified only glycosphingolipids, given their crucial role in the E. huxleyi –virus interaction [ 14 , 19 , 20 ].…”