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Marucci G, Zullino I, Bertuccini L, Camerini S, Cecchetti S, Pietrantoni A, Casella M, Vatta P, Greenwood AD, Fiorillo A, Lalle M. Re-Discovery of Giardiavirus: Genomic and Functional Analysis of Viruses from Giardia duodenalis Isolates. Biomedicines 2021; 9:654. [PMID: 34201207 PMCID: PMC8230311 DOI: 10.3390/biomedicines9060654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/29/2022] Open
Abstract
Giardiasis, caused by the protozoan parasite Giardia duodenalis, is an intestinal diarrheal disease affecting almost one billion people worldwide. A small endosymbiotic dsRNA viruses, G. lamblia virus (GLV), genus Giardiavirus, family Totiviridae, might inhabit human and animal isolates of G. duodenalis. Three GLV genomes have been sequenced so far, and only one was intensively studied; moreover, a positive correlation between GLV and parasite virulence is yet to be proved. To understand the biological significance of GLV infection in Giardia, the characterization of several GLV strains from naturally infected G. duodenalis isolates is necessary. Here we report high-throughput sequencing of four GLVs strains, from Giardia isolates of human and animal origin. We also report on a new, unclassified viral sequence (designed GdRV-2), unrelated to Giardiavirus, encoding and expressing for a single large protein with an RdRp domain homologous to Totiviridae and Botybirnaviridae. The result of our sequencing and proteomic analyses challenge the current knowledge on GLV and strongly suggest that viral capsid protein translation unusually starts with a proline and that translation of the RNA-dependent RNA polymerase (RdRp) occurs via a +1/-2 ribosomal frameshift mechanism. Nucleotide polymorphism, confirmed by mass-spectrometry analysis, was also observed among and between GLV strains. Phylogenetic analysis indicated the occurrence of at least two GLV subtypes which display different phenotypes and transmissibility in experimental infections of a GLV naïve Giardia isolate.
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Affiliation(s)
- Gianluca Marucci
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Ilaria Zullino
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Lucia Bertuccini
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Serena Camerini
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Serena Cecchetti
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Agostina Pietrantoni
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Marialuisa Casella
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Paolo Vatta
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Alex D. Greenwood
- Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany;
- Department of Veterinary Medicine, Freie Universität Berlin, 14195 Berlin, Germany
| | - Annarita Fiorillo
- Department of Biochemical Science “A. Rossi-Fanelli”, Sapienza University, 00185 Rome, Italy;
| | - Marco Lalle
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
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Cacciò SM, Sprong H. Giardia duodenalis: genetic recombination and its implications for taxonomy and molecular epidemiology. Exp Parasitol 2009; 124:107-12. [PMID: 19236865 DOI: 10.1016/j.exppara.2009.02.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 12/15/2008] [Accepted: 02/05/2009] [Indexed: 10/21/2022]
Abstract
Traditionally, species within the Giardia genus have been considered as eukaryotic organisms that show an absence of sexual reproduction in their simple life cycles. This apparent lack of sex has been challenged by a number of studies that have demonstrated (i) the presence in the Giardia duodenalis genome of true homologs of genes specifically involved in meiosis in other eukaryotes, and their stage-specific expression; (ii) the exchange of genetic material in different chromosomal regions among human isolates of the parasite; (iii) the fusion between cyst nuclei (karyogamy) and the transfer of genetic material (episomal plasmids) between them. These results are pivotal for the existence of sexual recombination. However, many details of the process remain elusive, and experimental data are still scarce. This review summarizes the experimental approaches and the results obtained, and discusses the implications of recombination from the standpoint of the taxonomy and molecular epidemiology of this widespread pathogen.
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Affiliation(s)
- Simone M Cacciò
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy.
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Jenkins MC, Higgins J, Abrahante JE, Kniel KE, O'Brien C, Trout J, Lancto CA, Abrahamsen MS, Fayer R. Fecundity of Cryptosporidium parvum is correlated with intracellular levels of the viral symbiont CPV. Int J Parasitol 2007; 38:1051-5. [PMID: 18096164 DOI: 10.1016/j.ijpara.2007.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 11/09/2007] [Accepted: 11/13/2007] [Indexed: 10/22/2022]
Abstract
Differences in the virulence and fecundity of Cryptosporidium parvum isolates have been observed by several researchers studying cryptosporidiosis. The purpose of the present study was to determine if there was a correlation between intracellular levels of the viral symbiont CPV in C. parvum and fecundity of two isolates of the parasite, namely C. parvum Beltsville (B) and C. parvum Iowa (I). Dairy calves infected with 10(6)C. parvum-B excreted 5-fold more oocysts compared with calves infected with the same number of C. parvum-I oocysts. The increased fecundity of the former strain was corroborated by semi-quantitative PCR assay of DNA isolated from cell cultures infected with either C. parvum-B or C. parvum-I. Quantitative reverse transcriptase-PCR analysis of viral RNA revealed a 3-fold greater number of CPV in C. parvum-B compared with C. parvum-I oocysts. These findings may indicate a role for CPV in fecundity and possibly virulence of C. parvum.
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Affiliation(s)
- M C Jenkins
- Animal Parasitic Diseases Laboratory, ARS, USDA, Beltsville, MD, USA.
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King BJ, Monis PT. Critical processes affecting Cryptosporidium oocyst survival in the environment. Parasitology 2006; 134:309-23. [PMID: 17096874 DOI: 10.1017/s0031182006001491] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 08/21/2006] [Accepted: 08/21/2006] [Indexed: 11/07/2022]
Abstract
Cryptosporidium are parasitic protozoans that cause gastrointestinal disease and represent a significant risk to public health. Cryptosporidium oocysts are prevalent in surface waters as a result of human, livestock and native animal faecal contamination. The resistance of oocysts to the concentrations of chlorine and monochloramine used to disinfect potable water increases the risk of waterborne transmission via drinking water. In addition to being resistant to commonly used disinfectants, it is thought that oocysts can persist in the environment and be readily mobilized by precipitation events. This paper will review the critical processes involved in the inactivation or removal of oocysts in the terrestrial and aquatic environments and consider how these processes will respond in the context of climate change.
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Affiliation(s)
- B J King
- The Co-operative Research Centre for Water Quality and Treatment, Australian Water Quality Centre, SA Water Corporation, Salisbury, South Australia 5108, Australia
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Abstract
Giardia lamblia is a common cause of diarrhea in humans and other mammals throughout the world. It can be distinguished from other Giardia species by light or electron microscopy. The two major genotypes of G. lamblia that infect humans are so different genetically and biologically that they may warrant separate species or subspecies designations. Trophozoites have nuclei and a well-developed cytoskeleton but lack mitochondria, peroxisomes, and the components of oxidative phosphorylation. They have an endomembrane system with at least some characteristics of the Golgi complex and encoplasmic reticulum, which becomes more extensive in encysting organisms. The primitive nature of the organelles and metabolism, as well as small-subunit rRNA phylogeny, has led to the proposal that Giardia spp. are among the most primitive eukaryotes. G. lamblia probably has a ploidy of 4 and a genome size of approximately 10 to 12 Mb divided among five chromosomes. Most genes have short 5' and 3' untranslated regions and promoter regions that are near the initiation codon. Trophozoites exhibit antigenic variation of an extensive repertoire of cysteine-rich variant-specific surface proteins. Expression is allele specific, and changes in expression from one vsp gene to another have not been associated with sequence alterations or gene rearrangements. The Giardia genome project promises to greatly increase our understanding of this interesting and enigmatic organism.
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Affiliation(s)
- R D Adam
- Department of Medicine, University of Arizona College of Medicine, 1501N. Campbell, Tucson, AZ 85724-5049, USA.
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Preisig O, Wingfield BD, Wingfield MJ. Coinfection of a fungal pathogen by two distinct double-stranded RNA viruses. Virology 1998; 252:399-406. [PMID: 9878619 DOI: 10.1006/viro.1998.9480] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Unsegmented double-stranded (ds)RNA viruses belonging to the family Totiviridae persistently infect protozoa and fungi. In this study, two totiviruses were found to coinfect the filamentous fungus Sphaeropsis sapinea, a well known pathogen of pines. Isometric, virus-like particles approximately 35 nm in diameter were isolated from extracts of this fungus. The nucleotide sequences of the genomes of the two S. sapinea RNA viruses named SsRV1 and SsRV2 were established. The linear genomes of 5163 and 5202 bp, respectively, are identically organized with two large, overlapping ORFs. The 5' located ORF1 probably encodes the coat protein, whereas the gene product of ORF2 shows the typical features of RNA-dependent RNA polymerases. The absence of a pseudoknot and a slippery site at the overlapping region between ORF1 and ORF2, as well as the shortness of that region, leads us to suggest that the translation of ORF2 of both viruses is internally initiated. The mode of translation and the genomic organization are similar to those of Helminthosporium victoriae 190S virus (Hv190SV; Huang, S., and Ghabrial, S. A. (1996). Proc. Natl. Acad. Sci. USA 93, 12541-12546). Hv190SV thus appears to be closely related to the SsRVs. Interestingly, based on amino acid sequence homology SsRV1 is more closely related to Hv190SV than to SsRV2.
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Affiliation(s)
- O Preisig
- Tree Pathology Co-operative Programme, University of Pretoria, Pretoria, 0002, South Africa
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