Samba-Louaka, A. | Search bioRxiv

bioRxiv2021

Overexpression of a G-protein coupled receptor-like gene affects encystment of Acanthamoeba castellanii

Acanthamoeba castellanii is an amphizoic free-living amoeba as it can be found in humans and in the environment. This amoeba represents an important reservoir of pathogenic microorganisms. Persistence of A. castellanii in the environment or in humans is allowed by the ability of the vegetative form to differentiate under cysts when surrounding conditions are unfavorable. In this study, we investigate the role of the ACA1_383450 gene during encystment of A. castellanii. This gene encodes a putative G-protein coupled receptor, which shares homology with human GPR107 and murine GPR108. Expression of the ACA1_383450 gene is transiently repressed at the early phase of encystment and its overexpression affects encystment of A. castellanii. This study reveals a new Acanthamoeba gene which could affect the encystment process. HighlightsO_LIThe ACA1_383450 gene encodes for a putative G-protein coupled receptor (GPCR). C_LIO_LIThe ACA1_383450 mRNA levels are down-regulated during the early phase of encystment. C_LIO_LIOverexpression of the ACA1_383450 gene affects formation of cysts. C_LI

microbiology↗

bioRxiv2019

Development of senescence biomarkers in the common woodlouse

Senescence, the decline of physiological parameters with increasing age, is a quasi-ubiquitous phenomenon in the living world. The observed patterns of senescence, however, can markedly differ across species and populations, between sexes, and even among individuals. To identify the drivers of this variation in senescence, experimental approaches are essential and involve the development of tools and new study models. Current knowledge of the senescence process is mostly based on studies on vertebrates and main information about senescence in invertebrates is mostly limited to model organisms such as Caenorhabditis elegans or Drosophila melanogaster. In this context, we tested whether biomarkers of vertebrate ageing could be used to study senescence in a new invertebrate model: the common woodlouse Armadillidium vulgare (Latreille, 1804). More specifically, we looked for the effect of age in woodlouse on three well-established physiological biomarkers of ageing in vertebrates: immune cells (cell size, density, and viability), {beta}-galactosidase activity, and the gene expression of telomerase reverse transcriptase (TERT), an essential subunit of telomerase protein. We found that the size of immune cells was higher in older individuals, whereas their density and viability decreased, and that the {beta}-galactosidase activity increased with age, whereas the TERT gene expression decreased. These findings demonstrate that woodlouse displays age-related changes in biomarkers of vertebrate senescence, with different patterns depending on gender. The tools used in studies of vertebrate senescence can thus be successfully used in studies of senescence of invertebrates such as the woodlouse. The application of commonly used tools to new biological models offers a promising approach to assess the diversity of senescence patterns across the tree of life.

evolutionary biology↗