Host-virus interactions and defense mechanisms for giant viruses.

Giant viruses, with virions larger than 200 nm and genomes larger than 340 kilobase pairs, modified the now outdated perception of the virosphere. With virions now reported reaching up to 1.5 μm in size and genomes of up to 2.

Sequence Similarities between Viroids and Human MicroRNAs.

Viroids are minute unencapsidated non-coding circular RNAs known to be present and to cause diseases only in plants. Infections were associated with the occurrence of specific single-stranded RNAs similar in size to miRNAs and endogenous small interfering RNAs, and viroid pathogenicity is suspected to occur through RNA interference. We looked for sequence similarities between viroids and the seed region of human microRNAs (hsa-miRNAs).

A virophage cross-species infection through mutant selection represses giant virus propagation, promoting host cell survival.

Virus adaptation to new hosts is a major cause of infectious disease emergence. This mechanism has been intensively studied in the context of zoonotic virus spillover, due to its impact on global health. However, it remains unclear for virophages, parasites of giant viruses and potential regulators of microbial communities.

Vermamoeba vermiformis CDC-19 draft genome sequence reveals considerable gene trafficking including with candidate phyla radiation and giant viruses.

Vermamoeba vermiformis is a predominant free-living amoeba in human environments and amongst the most common amoebae that can cause severe infections in humans. It is a niche for numerous amoeba-resisting microorganisms such as bacteria and giant viruses. Differences in the susceptibility to these giant viruses have been observed.

Core gene-based molecular detection and identification of Acanthamoeba species.

Acanthamoeba spp. are predominant free-living amoebae of water and soil. They have been used as tools for the isolation and culture of microbes that resist after their phagocytosis, such as Legionella-like bacteria, and, more recently giant viruses for which differences in permissiveness have been reported.

Investigation of potential pathogenicity of Willaertia magna by investigating the transfer of bacteria pathogenicity genes into its genome.

Willaertia magna c2c maky is a thermophilic amoeba closely related to the genus Naegleria. This free-living amoeba has the ability to eliminate Legionella pneumophila, which is an amoeba-resisting bacterium living in an aquatic environment. To prevent the proliferation of L.

Draft genome and description of Merdibacter massiliensis gen.nov., sp. nov., a new bacterium genus isolated from the human ileum.

We used phenotypic, genomic and phylogenetic information following the taxono-genomics approach to demonstrate that strain Marseille-P3254, isolated from an ileal sample of a 76-year old woman who underwent upper and lower digestive tract endoscopy for esophagitis and colonic polyp, is representative of a novel bacterial genus within the family Erysipelotrichaceae in the phylum Firmicutes. It is an anaerobic Gram-negative bacterium without catalase and oxidase activities. The genome of strain Marseille-P3254 is 2,468,496-bp long with a 40.

Discovery and Further Studies on Giant Viruses at the IHU Mediterranee Infection That Modified the Perception of the Virosphere.

The history of giant viruses began in 2003 with the identification of Since then, giant viruses of amoeba enlightened an unknown part of the viral world, and every discovery and characterization of a new giant virus modifies our perception of the virosphere. This notably includes their exceptional virion sizes from 200 nm to 2 µm and their genomic complexity with length, number of genes, and functions such as translational components never seen before. Even more surprising, possesses a unique mobilome composed of virophages, transpovirons, and a defense system against virophages named virophage resistance element (MIMIVIRE).

A Phylogenomic Study of Draft Genome Sequences Suggests Genetic Exchanges With Giant Viruses.

are ubiquitous phagocytes predominant in soil and water which can ingest many microbes. Giant viruses of amoebae are listed among the -resisting microorganisms. Their sympatric lifestyle within amoebae is suspected to promote lateral nucleotide sequence transfers.

Deciphering the genomes of 16 Acanthamoeba species does not provide evidence of integration of known giant virus-associated mobile genetic elements.

Giant viruses infect protozoa, especially amoebae of the genus Acanthamoeba. These viruses possess genetic elements named Mobilome. So far, this mobilome comprises provirophages which are integrated into the genome of their hosts, transpovirons, and Maverick/Polintons.