| giant viruses in the oceans: the 4th algal virus workshop. | giant double-stranded dna viruses (such as record breaking acanthamoeba polyphaga mimivirus), with particle sizes of 0.2 to 0.6 microm, genomes of 300 kbp to 1.200 kbp, and commensurate complex gene contents, constitute an evolutionary mystery. they challenge the common vision of viruses, traditionally seen as highly streamlined genomes optimally fitted to the smallest possible--filterable--package. such giant viruses are now discovered in increasing numbers through the systematic sampling of oc ... | 2005 | 15967028 |
| mimivirus relatives in the sargasso sea. | the discovery and genome analysis of acanthamoeba polyphaga mimivirus, the largest known dna virus, challenged much of the accepted dogma regarding viruses. its particle size (>400 nm), genome length (1.2 million bp) and huge gene repertoire (911 protein coding genes) all contribute to blur the established boundaries between viruses and the smallest parasitic cellular organisms. phylogenetic analyses also suggested that the mimivirus lineage could have emerged prior to the individualization of c ... | 2005 | 16105173 |
| mimivirus gene promoters exhibit an unprecedented conservation among all eukaryotes. | the initial analysis of the recently sequenced genome of acanthamoeba polyphaga mimivirus, the largest known double-stranded dna virus, predicted a proteome of size and complexity more akin to small parasitic bacteria than to other nucleocytoplasmic large dna viruses and identified numerous functions never before described in a virus. it has been proposed that the mimivirus lineage could have emerged before the individualization of cellular organisms from the three domains of life. an exhaustive ... | 2005 | 16203998 |
| gene and genome duplication in acanthamoeba polyphaga mimivirus. | gene duplication is key to molecular evolution in all three domains of life and may be the first step in the emergence of new gene function. it is a well-recognized feature in large dna viruses but has not been studied extensively in the largest known virus to date, the recently discovered acanthamoeba polyphaga mimivirus. here, i present a systematic analysis of gene and genome duplication events in the mimivirus genome. i found that one-third of the mimivirus genes are related to at least one ... | 2005 | 16254344 |
| mimivirus and the emerging concept of "giant" virus. | the recently discovered acanthamoeba polyphaga mimivirus is the largest known dna virus. its particle size (750 nm), genome length (1.2 million bp) and large gene repertoire (911 protein coding genes) blur the established boundaries between viruses and parasitic cellular organisms. in addition, the analysis of its genome sequence identified many types of genes never before encountered in a virus, including aminoacyl-trna synthetases and other central components of the translation machinery previ ... | 2006 | 16469402 |
| ameba-associated microorganisms and diagnosis of nosocomial pneumonia. | to elucidate the role of ameba-associated microorganisms (aams) as etiologic agents of pneumonia, we screened for legionella spp., parachlamydia acanthamoeba, afipia sp., bosea spp., bradyrhizobium spp., mesorhizobium amorphae, rasbo bacterium, azorhizobium caulinodans, acanthamoeba polyphaga mimivirus, and conventional microorganisms in 210 pneumonia patients in intensive-care units by using culture, polymerase chain reaction, and serologic testing. these resulted in 59 diagnoses in 40 patients ... | 2006 | 16494750 |
| acanthamoeba polyphaga mimivirus ndk: preliminary crystallographic analysis of the first viral nucleoside diphosphate kinase. | the complete sequence of the largest known double-stranded dna virus, acanthamoeba polyphaga mimivirus, has recently been determined [raoult et al. (2004), science, 306, 1344-1350] and revealed numerous genes not expected to be found in a virus. a comprehensive structural and functional study of these gene products was initiated [abergel et al. (2005), acta cryst. f61, 212-215] both to better understand their role in the virus physiology and to obtain some clues to the origin of dna viruses. her ... | 2005 | 16511098 |
| isolation, characterization, and bioinformatic analysis of calmodulin-binding protein cmbb reveals a novel tandem ip22 repeat common to many dictyostelium and mimivirus proteins. | a novel calmodulin-binding protein cmbb from dictyostelium discoideum is encoded in a single gene. northern analysis reveals two cmbb transcripts first detectable at 4 h during multicellular development. western blotting detects an approximately 46.6 kda protein. sequence analysis and calmodulin-agarose binding studies identified a "classic" calcium-dependent calmodulin-binding domain (179ipkslrslflgkgynqplef198) but structural analyses suggest binding may not involve classic alpha-helical calmo ... | 2006 | 16777069 |
| mimivirus giant particles incorporate a large fraction of anonymous and unique gene products. | acanthamoeba polyphaga mimivirus is the largest known virus in both particle size and genome complexity. its 1.2-mb genome encodes 911 proteins, among which only 298 have predicted functions. the composition of purified isolated virions was analyzed by using a combined electrophoresis/mass spectrometry approach allowing the identification of 114 proteins. besides the expected major structural components, the viral particle packages 12 proteins unambiguously associated with transcriptional machin ... | 2006 | 16971431 |
| pneumonia in mice inoculated experimentally with acanthamoeba polyphaga mimivirus. | in an attempt to elucidate whether acanthamoeba polyphaga mimivirus (apm) was pathogenic (i.e., induces histological evidence of inflammation or tissue destruction or both) in mammalian host, we inoculated adult balb/c (n=6) and c57bl/6 (n=6) mice with apm via intracardiac route. c57bl/6 mice developed histopathological features of pneumonia by post-inoculation day (pid) 3 and balb/c mice, by pid7. the histopathological features of pneumonia, characterized by the presence of thickened alveolar w ... | 2007 | 17188457 |
| ultrastructural characterization of the giant volcano-like virus factory of acanthamoeba polyphaga mimivirus. | acanthamoeba polyphaga mimivirus is a giant double-stranded dna virus defining a new genus, the mimiviridae, among the nucleo-cytoplasmic large dna viruses (ncldv). we used utrastructural studies to shed light on the different steps of the mimivirus replication cycle: entry via phagocytosis, release of viral dna into the cell cytoplasm through fusion of viral and vacuolar membranes, and finally viral morphogenesis in an extraordinary giant cytoplasmic virus factory (vf). fluorescent staining of ... | 2007 | 17389919 |
| elad, a deubiquitinating protease expressed by e. coli. | ubiquitin and ubiquitin-like proteins (ubl) are designed to modify polypeptides in eukaryotes. covalent binding of ubiquitin or ubls to substrate proteins can be reversed by specific hydrolases. one particular set of cysteine proteases, the ce clan, which targets ubiquitin and ubls, has homologs in eukaryotes, prokaryotes, and viruses. | 2007 | 17440617 |
| marine mimivirus relatives are probably large algal viruses. | acanthamoeba polyphaga mimivirus is the largest known ds-dna virus and its 1.2 mb-genome sequence has revealed many unique features. mimivirus occupies an independent lineage among eukaryotic viruses and its known hosts include only species from the acanthamoeba genus. the existence of mimivirus relatives was first suggested by the analysis of the sargasso sea metagenomic data. | 2008 | 18215256 |
| screening pneumonia patients for mimivirus. | acanthamoeba polyphaga mimivirus (apm), a virus of free-living amebae, has reportedly caused human respiratory disease. using 2 newly developed real-time pcr assays, we screened 496 respiratory specimens from 9 pneumonia-patient populations for apm. this virus was not detected in any specimen, which suggests it is not a common respiratory pathogen. | 2008 | 18325263 |
| distinct dna exit and packaging portals in the virus acanthamoeba polyphaga mimivirus. | icosahedral double-stranded dna viruses use a single portal for genome delivery and packaging. the extensive structural similarity revealed by such portals in diverse viruses, as well as their invariable positioning at a unique icosahedral vertex, led to the consensus that a particular, highly conserved vertex-portal architecture is essential for viral dna translocations. here we present an exception to this paradigm by demonstrating that genome delivery and packaging in the virus acanthamoeba p ... | 2008 | 18479185 |
| ameobal pathogen mimivirus infects macrophages through phagocytosis. | mimivirus, or acanthamoeba polyphaga mimivirus (apmv), a giant double-stranded dna virus that grows in amoeba, was identified for the first time in 2003. entry by phagocytosis within amoeba has been suggested but not demonstrated. we demonstrate here that apmv was internalized by macrophages but not by non-phagocytic cells, leading to productive apmv replication. clathrin- and caveolin-mediated endocytosis pathways, as well as degradative endosome-mediated endocytosis, were not used by apmv to i ... | 2008 | 18551172 |
| the virophage as a unique parasite of the giant mimivirus. | viruses are obligate parasites of eukarya, archaea and bacteria. acanthamoeba polyphaga mimivirus (apmv) is the largest known virus; it grows only in amoeba and is visible under the optical microscope. mimivirus possesses a 1,185-kilobase double-stranded linear chromosome whose coding capacity is greater than that of numerous bacteria and archaea1, 2, 3. here we describe an icosahedral small virus, sputnik, 50 nm in size, found associated with a new strain of apmv. sputnik cannot multiply in aca ... | 2008 | 18690211 |
| mimivirus. | acanthamoeba polyphaga mimivirus, the first representative and prototype member of the mimiviridae, is the latest addition to the menagerie of lesser-known big dna viruses. due to the size of its particle--a fiber-covered icosahedral protein capsid with a diameter of 0.7 microm--mimivirus was initially mistaken for an intracellular parasitic bacteria. its 1.2-mb genome sequence was then found to encode more than 900 proteins, many of them associated with functions never before encountered in a v ... | 2009 | 19216436 |
| evidence that the intra-amoebal legionella drancourtii acquired a sterol reductase gene from eukaryotes. | free-living amoebae serve as a natural reservoir for some bacteria that have evolved into "amoeba-resistant" bacteria. among these, some are strictly intra-amoebal, such as candidatus "protochlamydia amoebophila" (candidatus "p. amoebophila"), whose genomic sequence is available. we sequenced the genome of legionella drancourtii (l. drancourtii), another recently described intra-amoebal bacterium. by comparing these two genomes with those of their closely related species, we were able to study t ... | 2009 | 19327142 |
| dissecting the unique nucleotide specificity of mimivirus nucleoside diphosphate kinase. | the analysis of the acanthamoeba polyphaga mimivirus genome revealed the first virus-encoded nucleoside diphosphate kinase (ndk), an enzyme that is central to the synthesis of rna and dna, ubiquitous in cellular organisms, and well conserved among the three domains of life. in contrast with the broad specificity of cellular ndks for all types of ribo- and deoxyribonucleotides, the mimivirus enzyme exhibits a strongly preferential affinity for deoxypyrimidines. in order to elucidate the molecular ... | 2009 | 19439473 |
| the first virally encoded cytochrome p450. | the genome sequence of the giant virus acanthamoeba polyphaga mimivirus revealed the presence of two putative cytochrome p450 (cyp) genes. the product of one of the two predicted cyp genes (yp_143162) showed low-level homology to sterol 14-demethylase (cyp51) and contained a c-terminal polypeptide domain of unknown function. yp_143162 expression (without an n-terminal membrane binding domain) in escherichia coli yields a cyp protein which gives a reduced co difference maximum at 448 nm and was f ... | 2009 | 19515774 |
| specific recognition of the major capsid protein of acanthamoeba polyphaga mimivirus by sera of patients infected by francisella tularensis. | francisella tularensis, a gram-negative cocobacillus responsible for tularemia, especially severe pneumonia, is a facultative intracellular bacterium classified as a biological agent of category a. acanthamoeba polyphaga mimivirus (apm) is a recently discovered giant virus suspected to be an agent of both community- and hospital-acquired pneumonia. during specificity testing of antibody to apm detection, it was observed that nearly all patients infected by f. tularensis had elevated antibody tit ... | 2009 | 19538509 |
| vaccinia-like cytoplasmic replication of the giant mimivirus. | poxviruses are considered to be unique among all dna viruses, because their infection cycle is carried out exclusively in the host cytoplasm. such an infection strategy is of interest, because it necessitates generation of elaborate factories in which viral replication and assembly are promoted. by using diverse imaging techniques, we show that the infection cycle of the largest virus currently identified, the acanthamoeba polyphaga mimivirus, similarly occurs exclusively in the host cytoplasm. ... | 2010 | 20231474 |
| the origins of eukaryotic-like proteins in legionella pneumophila. | legionella pneumophila, the causative agent of legionnaires' disease, is known to be an intracellular pathogen of multiple species of protozoa and is assumed to have co-evolved with these organisms for millions of years. genome sequencing of l. pneumophila strains has revealed an abundance of eukaryotic-like proteins (elps). here, we study the evolution of these elps, in order to investigate their origin. thirty-four new elps were identified, based on a higher similarity to eukaryotic proteins t ... | 2010 | 20537944 |
| identification of an l-rhamnose synthetic pathway in two nucleocytoplasmic large dna viruses. | nucleocytoplasmic large dna viruses (ncldvs) are characterized by large genomes that often encode proteins not commonly found in viruses. two species in this group are acanthocystis turfacea chlorella virus 1 (atcv-1) (family phycodnaviridae, genus chlorovirus) and acanthamoeba polyphaga mimivirus (family mimiviridae), commonly known as mimivirus. atcv-1 and other chlorovirus members encode enzymes involved in the synthesis and glycosylation of their structural proteins. in this study, we identi ... | 2010 | 20538863 |
| gene repertoire of amoeba-associated giant viruses. | acanthamoeba polyphaga mimivirus, marseillevirus, and sputnik, a virophage, are intra-amoebal viruses that have been isolated from water collected in cooling towers. they have provided fascinating data and have raised exciting questions about viruses definition and evolution. mimivirus and marseillevirus have been classified in the nucleo-cytoplasmic large dna viruses (ncldvs) class. their genomes are the largest and fifth largest viral genomes sequenced so far. the gene repertoire of these amoe ... | 2010 | 20551685 |
| tentative characterization of new environmental giant viruses by maldi-tof mass spectrometry. | metagenomic studies have revealed that acanthamoeba polyphaga mimivirus relatives are common in the environment; however, only three acanthamoeba-growing giant viruses have been isolated from hundreds of environmental samples. we attempted herein to isolate new acanthamoeba-growing giant viruses from environmental samples. | 2010 | 20551686 |
| giant virus with a remarkable complement of genes infects marine zooplankton. | as major consumers of heterotrophic bacteria and phytoplankton, microzooplankton are a critical link in aquatic foodwebs. here, we show that a major marine microflagellate grazer is infected by a giant virus, cafeteria roenbergensis virus (crov), which has the largest genome of any described marine virus (≈730 kb of double-stranded dna). the central 618-kb coding part of this at-rich genome contains 544 predicted protein-coding genes; putative early and late promoter motifs have been detected an ... | 2010 | 20974979 |
| viruses with more than 1,000 genes: mamavirus, a new acanthamoeba polyphaga mimivirus strain, and reannotation of mimivirus genes. | the genome sequence of the mamavirus, a new acanthamoeba polyphaga mimivirus strain, is reported. with 1,191,693 nt in length and 1,023 predicted protein-coding genes, the mamavirus has the largest genome among the known viruses. the genomes of the mamavirus and the previously described mimivirus are highly similar in both the protein-coding genes and the intergenic regions. however, the mamavirus contains an extra 5'-terminal segment that encompasses primarily disrupted duplicates of genes pres ... | 2011 | 21705471 |
| Mimivirus collagen is modified by bifunctional lysyl hydroxylase and glycosyltransferase enzyme. | Collagens, the most abundant proteins in animals, are modified by hydroxylation of proline and lysine residues and by glycosylation of hydroxylysine. Dedicated prolyl hydroxylase, lysyl hydroxylase, and collagen glycosyltransferase enzymes localized in the endoplasmic reticulum mediate these modifications prior to the formation of the collagen triple helix. Whereas collagen-like proteins have been described in some fungi, bacteria, and viruses, the post-translational machinery modifying collagen ... | 2011 | 22045808 |
| exposure to mimivirus collagen promotes arthritis. | collagens, the most abundant proteins in animals, also occur in some recently described nucleocytoplasmic large dna viruses such as mimiviridae, which replicate in amoebae. to clarify the impact of viral collagens on the immune response of animals exposed to mimiviridae, we have investigated the localization of collagens in acanthamoeba polyphaga mimivirus particles and the response of mice to immunization with mimivirus particles. using protein biotinylation, we have first shown that viral coll ... | 2014 | 24173233 |
| acanthamoeba polyphaga mimivirus virophage seroconversion in travelers returning from laos. | during january 2010, a husband and wife returned from laos to france with probable parasitic disease. increased antibodies against an acanthamoeba polyphaga mimivirus virophage indicated seroconversion. while in laos, they had eaten raw fish, a potential source of the virophage. this virophage, associated with giant viruses suspected to cause pneumonia, could be an emerging pathogen. | 2012 | 22932431 |
| a brazilian marseillevirus is the founding member of a lineage in family marseilleviridae. | in 2003, acanthamoeba polyphaga mimivirus (apmv) was discovered as parasitizing acanthamoeba. it was revealed to exhibit remarkable features, especially odd genomic characteristics, and founded viral family mimiviridae. subsequently, a second family of giant amoebal viruses was described, marseilleviridae, whose prototype member is marseillevirus, discovered in 2009. currently, the genomes of seven different members of this family have been fully sequenced. previous phylogenetic analysis suggest ... | 2016 | 26978387 |
| extensive in silico analysis of mimivirus coded rab gtpase homolog suggests a possible role in virion membrane biogenesis. | rab gtpases are the key regulators of intracellular membrane trafficking in eukaryotes. many viruses and intracellular bacterial pathogens have evolved to hijack the host rab gtpase functions, mainly through activators and effector proteins, for their benefit. acanthamoeba polyphaga mimivirus (apmv) is one of the largest viruses and belongs to the monophyletic clade of nucleo-cytoplasmic large dna viruses (ncldv). the inner membrane lining is integral to the apmv virion structure. apmv assembly ... | 2015 | 26441866 |
| cedratvirus, a double-cork structured giant virus, is a distant relative of pithoviruses. | most viruses are known for the ability to cause symptomatic diseases in humans and other animals. the discovery of acanthamoeba polyphaga mimivirus and other giant amoebal viruses revealed a considerable and previously unknown area of uncharacterized viral particles. giant viruses have been isolated from various environmental samples collected from very distant geographic places, revealing a ubiquitous distribution. their morphological and genomic features are fundamental elements for classifyin ... | 2016 | 27827884 |
| mimivirus fibrils are important for viral attachment to the microbial world by a diverse glycoside interaction repertoire. | acanthamoeba polyphaga mimivirus (apmv) is a giant virus from the mimiviridae family. it has many unusual features, such as a pseudoicosahedral capsid that presents a starfish shape in one of its vertices, through which the ∼ 1.2-mb double-stranded dna is released. it also has a dense glycoprotein fibril layer covering the capsid that has not yet been functionally characterized. here, we verified that although these structures are not essential for viral replication, they are truly necessary for ... | 2015 | 26378162 |
| "marseilleviridae", a new family of giant viruses infecting amoebae. | the family "marseilleviridae" is a new proposed taxon for giant viruses that infect amoebae. its first member, acanthamoeba polyphaga marseillevirus (apmav), was isolated in 2007 by culturing on amoebae a water sample collected from a cooling tower in paris, france. apmav has an icosahedral shape with a diameter of ≈250 nm. its genome is a double-stranded circular dna that is 368,454 base pairs (bp) in length. the genome has a gc content of 44.7 % and is predicted to encode 457 proteins. phyloge ... | 2013 | 23188494 |
| mimivirus: leading the way in the discovery of giant viruses of amoebae. | the accidental discovery of the giant virus of amoeba - acanthamoeba polyphaga mimivirus (apmv; more commonly known as mimivirus) - in 2003 changed the field of virology. viruses were previously defined by their submicroscopic size, which probably prevented the search for giant viruses, which are visible by light microscopy. extended studies of giant viruses of amoebae revealed that they have genetic, proteomic and structural complexities that were not thought to exist among viruses and that are ... | 2017 | 28239153 |
| mimiviruses and the human interferon system: viral evasion of classical antiviral activities, but inhibition by a novel interferon-β regulated immunomodulatory pathway. | in this review we discuss the role of mimiviruses as potential human pathogens focusing on clinical and evolutionary evidence. we also propose a novel antiviral immunomodulatory pathway controlled by interferon-β (ifn-β) and mediated by immune-responsive gene 1 (irg1) and itaconic acid, its product. acanthamoeba polyphaga mimivirus (apmv) was isolated from amoebae in a hospital while investigating a pneumonia outbreak. mimivirus ubiquity and role as protist pathogens are well understood, and its ... | 2017 | 28079476 |
| giant mimivirus r707 encodes a glycogenin paralogue polymerizing glucose through α- and β-glycosidic linkages. | acanthamoeba polyphaga mimivirus is a giant virus encoding 1262 genes among which many were previously thought to be exclusive to cellular life. for example, mimivirus genes encode enzymes involved in the biosynthesis of nucleotide sugars and putative glycosyltransferases. we identified in mimivirus a glycogenin-1 homologous gene encoded by the open reading frame r707. the r707 protein was found to be active as a polymerizing glucosyltransferase enzyme. like glycogenin-1, r707 activity was dival ... | 2016 | 27433018 |
| updating strategies for isolating and discovering giant viruses. | almost fifteen years ago, the discovery of acanthamoeba polyphaga mimivirus, the first giant virus, changed how we define a virus. it was discovered incidentally in a process of isolating legionella sp. from environmental samples in the context of pneumonia epidemics using a co-culture system with acanthamoeba. since then, much effort and improvement has been put into the original technique. in addition to the known families of mimiviridae and marseilleviridae, four new proposed families of gian ... | 2016 | 27039269 |
| acanthamoeba and mimivirus interactions: the role of amoebal encystment and the expansion of the 'cheshire cat' theory. | acanthamoeba are natural hosts for giant viruses and their life cycle comprises two stages: a trophozoite and a cryptobiotic cyst. encystment involves a massive turnover of cellular components under molecular regulation. giant viruses are able to infect only the trophozoite, while cysts are resistant to infection. otherwise, upon infection, mimiviruses are able to prevent encystment. this review highlights the important points of acanthamoeba and giant virus interactions regarding the encystment ... | 2016 | 26820447 |
| acanthamoeba polyphaga mimivirus prevents amoebal encystment-mediating serine proteinase expression and circumvents cell encystment. | acanthamoeba is a genus of free-living amoebas distributed worldwide. few studies have explored the interactions between these protozoa and their infecting giant virus, acanthamoeba polyphaga mimivirus (apmv). here we show that, once the amoebal encystment is triggered, trophozoites become significantly resistant to apmv. otherwise, upon infection, apmv is able to interfere with the expression of a serine proteinase related to amoebal encystment and the encystment can no longer be triggered. | 2015 | 25520511 |
| looking at protists as a source of pathogenic viruses. | in the environment, protozoa are predators of bacteria and feed on them. the possibility that some protozoa could be a source of human pathogens is consistent with the discovery that free-living amoebae were the reservoir of legionella pneumophila, the agent of legionnaires' disease. later, while searching for legionella in the environment using amoeba co-culture, the first giant virus, acanthamoeba polyphaga mimivirus, was discovered. since then, many other giant viruses have been isolated, inc ... | 2014 | 25218687 |
| acanthamoeba polyphaga mimivirus and other giant viruses: an open field to outstanding discoveries. | in 2003, acanthamoeba polyphaga mimivirus (apmv) was first described and began to impact researchers around the world, due to its structural and genetic complexity. this virus founded the family mimiviridae. in recent years, several new giant viruses have been isolated from different environments and specimens. giant virus research is in its initial phase and information that may arise in the coming years may change current conceptions of life, diversity and evolution. thus, this review aims to ... | 2014 | 24976356 |
| the virion of cafeteria roenbergensis virus (crov) contains a complex suite of proteins for transcription and dna repair. | cafeteria roenbergensis virus (crov) is a giant virus of the mimiviridae family that infects the marine phagotrophic flagellate c. roenbergensis. crov possesses a dna genome of ~730 kilobase pairs that is predicted to encode 544 proteins. we analyzed the protein composition of purified crov particles by liquid chromatography-tandem mass spectrometry (lc-ms/ms) and identified 141 virion-associated crov proteins and 60 host proteins. data are available via proteomexchange with identifier pxd000993 ... | 2014 | 24973308 |
| growing a giant: evaluation of the virological parameters for mimivirus production. | acanthamoeba polyphaga mimivirus (apmv) was described in 2003, and due to its unique structural and genetic complexity, the viral family mimiviridae was created. apmv prompted the creation of an open field of study on the function of hundreds of never-before-seen open reading frames (orfs) and their roles in virus-host interactions. in recent years, several giant viruses have been isolated from different environments and specimens. although the scientific community has experienced a remarkable a ... | 2014 | 24972367 |
| samba virus: a novel mimivirus from a giant rain forest, the brazilian amazon. | the identification of novel giant viruses from the nucleocytoplasmic large dna viruses group and their virophages has increased in the last decade and has helped to shed light on viral evolution. this study describe the discovery, isolation and characterization of samba virus (smbv), a novel giant virus belonging to the mimivirus genus, which was isolated from the negro river in the brazilian amazon. we also report the isolation of an smbv-associated virophage named rio negro (rnv), which is the ... | 2014 | 24886672 |
| o-linked glycosylation in acanthamoeba polyphaga mimivirus. | acanthamoeba polyphaga mimivirus is a member of the giant nucleocytoplasmic large dna viruses, infecting various acanthamoeba spp. the genomes of giant viruses encode components previously thought to be exclusive to cellular life, such as proteins involved in nucleic acid and protein synthesis. recent work on enzymes involved in carbohydrate biosynthesis and metabolism show that instead of utilizing host cell resources, mimivirus produces its own glycosylation machinery. to obtain a more detaile ... | 2014 | 24794008 |
| genome segregation and packaging machinery in acanthamoeba polyphaga mimivirus is reminiscent of bacterial apparatus. | genome packaging is a critical step in the virion assembly process. the putative atp-driven genome packaging motor of acanthamoeba polyphaga mimivirus (apmv) and other nucleocytoplasmic large dna viruses (ncldvs) is a distant ortholog of prokaryotic chromosome segregation motors, such as ftsk and hera, rather than other viral packaging motors, such as large terminase. intriguingly, apmv also encodes other components, i.e., three putative serine recombinases and a putative type ii topoisomerase, ... | 2014 | 24623441 |
| acanthamoeba polyphaga mimivirus stability in environmental and clinical substrates: implications for virus detection and isolation. | viruses are extremely diverse and abundant and are present in countless environments. giant viruses of the megavirales order have emerged as a fascinating research topic for virologists around the world. as evidence of their ubiquity and ecological impact, mimiviruses have been found in multiple environmental samples. however, isolation of these viruses from environmental samples is inefficient, mainly due to methodological limitations and lack of information regarding the interactions between v ... | 2014 | 24498379 |
| a resourceful giant: apmv is able to interfere with the human type i interferon system. | acanthamoeba polyphaga mimivirus (apmv) is a giant, double-stranded virus of the mimiviridae family that was discovered in 2003. recent studies have shown that this virus is able to replicate in murine and human phagocytes and might be considered a putative human pathogen that causes pneumonia. however, there is little data regarding apmv and its host defense relationship. in the present study, we investigated how some components of the interferon (ifn) system are stimulated by apmv in human per ... | 2014 | 24295593 |
| amoebas as mimivirus bunkers: increased resistance to uv light, heat and chemical biocides when viruses are carried by amoeba hosts. | amoebas of the genus acanthamoeba are protists that are associated with human disease and represent a public health concern. they can harbor pathogenic microorganisms, acting as a platform for pathogen replication. acanthamoeba polyphaga mimivirus (apmv), the type species of the genus mimivirus, family mimiviridae, represents the largest group of amoeba-associated viruses that has been described to date. recent studies have demonstrated that apmv and other giant viruses may cause pneumonia. amoe ... | 2014 | 24271007 |
| alcohol disinfection procedure for isolating giant viruses from contaminated samples. | giant viruses of the megavirales order have been neglected in the literature because they are removed from samples during viral purification for viral metagenomic studies. isolation via amoeba coculture has low efficiency and is extremely time-consuming. thus, our objective was to improve megavirales detection and recovery by using a new protocol that will eliminate most bacteria present in environmental samples while preserving giant virus viability. | 2013 | 24157890 |
| mimivirus is not a frequent cause of ventilator-associated pneumonia in critically ill patients. | acanthamoeba polyphaga mimivirus (apmv) belongs to the amoebae-associated microorganisms. antibodies to apmv have been found in patients with pneumonia suggesting a potential role as a respiratory pathogen. in addition, positive serology for apmv was associated with an increased duration of mechanical ventilation and intensive care unit stay in patients with ventilator-associated pneumonia. the aim of the present study was to assess the presence of apmv in bronchoalveolar lavage fluid samples of ... | 2013 | 23861144 |
| broad spectrum of mimiviridae virophage allows its isolation using a mimivirus reporter. | the giant virus mimiviridae family includes 3 groups of viruses: group a (includes acanthamoeba polyphaga mimivirus), group b (includes moumouvirus) and group c (includes megavirus chilensis). virophages have been isolated with both group a mimiviridae (the mamavirus strain) and the related cafeteria roenbergensis virus, and they have also been described by bioinformatic analysis of the phycodnavirus. here, we found that the first two strains of virophages isolated with group a mimiviridae can m ... | 2013 | 23596530 |
| amoebae as battlefields for bacteria, giant viruses, and virophages. | when amoebae are simultaneously infected with acanthamoeba polyphaga mimivirus (apm) and the strictly intracellular babl1 bacterium, the latter is always lost after serial subculturing. we showed that the virophage sputnik 1, by reducing apm fitness, preserved babl1 growth in acute and chronic models. this capability of a virophage to modulate the virulence of mimiviruses highlights the competition that occurs between them during natural host infection. | 2013 | 23388714 |
| the n-terminal fragment of acanthamoeba polyphaga mimivirus tyrosyl-trna synthetase (tyrrs(apm)) is a monomer in solution. | acanthamoeba polyphaga mimivirus tyrosyl-trna synthetase (tyrrsapm) was the first reported aminoacyl-trna synthetase of viral origin. the previous crystal structure of tyrrsapm showed a non-canonical orientation of the dimer conformation and the cp1 domain, responsible for dimer formation, displays a major modification of a motif structurally conserved in other tyrrs structures. an earlier study reported that bacillus stearothermophilus n-terminal tyrrs exists as a dimer under native conditions. ... | 2013 | 23384724 |
| virucidal activity of chemical biocides against mimivirus, a putative pneumonia agent. | acanthamoeba polyphaga mimivirus (apmv), the largest known virus, has been studied as a putative pneumonia agent, especially in hospital environments. despite the repercussions of the discovery of apmv, there has been no study related to the control of apmv and the susceptibility of this virus to disinfectants. | 2012 | 22947947 |
| lamarckian evolution of the giant mimivirus in allopatric laboratory culture on amoebae. | acanthamoeba polyphaga mimivirus has been subcultured 150 times on germ-free amoebae. this allopatric niche is very different from that found in the natural environment, where the virus is in competition with many other organisms. in this experiment, substantial gene variability and loss occurred concurrently with the emergence of phenotypically different viruses. we sought to quantify the respective roles of lamarckian and darwinian evolution during this experiment. we postulated that the mimiv ... | 2012 | 22919682 |