Quantitative conversion of biomass in giant DNA virus infection

Abstract

Bioconversion of organic materials is the foundation of many applications in chemical engineering, microbiology and biochemistry. Herein, we introduce a new methodology to quantitatively determine conversion of biomass in viral infections while simultaneously imaging morphological changes of the host cell. As proof of concept, the viral replication of an unidentified giant DNA virus and the cellular response of an amoebal host are studied using soft X-ray microscopy, titration dilution measurements and thermal gravimetric analysis. We find that virions produced inside the cell are visible from 18 h post infection and their numbers increase gradually to a burst size of 280–660 virions. Due to the large size of the virion and its strong X-ray absorption contrast, we estimate that the burst size corresponds to a conversion of 6–12% of carbonaceous biomass from amoebal host to virus. The occurrence of virion production correlates with the appearance of a possible viral factory and morphological changes in the phagosomes and contractile vacuole complex of the amoeba, whereas the nucleus and nucleolus appear unaffected throughout most of the replication cycle.

Morphological and Genomic Features of the New Klosneuvirinae Isolate Fadolivirus IHUMI-VV54

“…The first description of vacuolar (H+)-ATPase highlights the close proximity of V and F-type of ATPase D in their catalytic function (Nelson et al, 1995). Recently, during a giant viral infection, it was shown that the shift of the carbonaceous biomass of the host concerned 6-17% for viral production, probably due to a Cedratvirus (Kördel et al, 2021). This observation underlined the fact that viral production requires a greater production of energy by the infected cells.…”

Soft X-ray Microscopy in Cell Biology: Current Status, Contributions and Prospects

“…Kördel et al [ 50 ] studied the transfer of a substance from the host cell to the virus during the development of an unidentified giant DNA virus (presumably Cedratvirus) infecting the amoeba Acanthamoeba castellanii . Updated data were obtained on the number of virions formed during viral replication.…”

“…A structure has been discovered which may potentially be a viral replication factory. It has been shown that the changes affect the contractile vacuole and phagosomes, but not the nucleus, which allows the cell to function until lysis, increasing the efficiency of virus production [ 50 ]. The linear dependence of absorption coefficients on the organic matter concentration, visualized in cryo-SXT images, combined with the ability to process the entire cell volume, makes cryo-SXT a preferred tool for conducting this type of research, compared to EM, which allows the detection of much smaller virions but imposes restrictions on sample volumes.…”

“…В работе [50] изучен перенос вещества от клеткихозяина к вирусу в ходе развития неидентифицированного гигантского ДНК-вируса (предположительное Cedratvirus), заражающего амебу Acanthamoeba castellanii. Изучена динамика развития инфекции, уточнены данные по количеству вирионов, формирующихся в ходе размножения вируса.…”

“…Обнаружена структура, возможно, являющаяся фабрикой репликации вируса. Показано, что изменения затрагивают сократимую вакуоль и фагосомы, но не ядро, что позволяет клетке функционировать вплоть до лизиса, увеличивая эффективность продукции вируса [50]. Линейная зависимость коэффициентов поглощения от концентрации органического вещества, визуализируемая на ктМРД-изображениях, плюс возможность обработки всего объема клетки делают ктМРД предпочтительным инструментом для проведения такого рода исследований по сравнению с ЭМ, которая позволяет обнаруживать вирионы куда меньшего размера, но ставит ограничения на объемы выборки.…”