Daniele Corsaro - Academia.edu (original) (raw)

Papers by Daniele Corsaro

European journal of protistology, Jun 1, 2024

Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of ... more Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both A. castellanii and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, Acanthamoeba terricola Pussard, 1964, but both were successively synonymized with A. castellanii. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in Acanthamoeba, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of A. castellanii. In this study, we compared the type strain of A. terricola with the Neff strain and A. castellanii, and analysed the available molecular data including new sequences obtained from A. terricola. Here we provide molecular evidence to validate the species A. terricola. The Neff strain is therefore transferred to A. terricola and should no longer be considered as belonging to A. castellanii.

Microorganisms, 2024

The molecular classification of Acanthamoeba is currently based on the analysis of 18S rDNA seque... more The molecular classification of Acanthamoeba is currently based on the analysis of 18S rDNA sequences, delimiting around twenty genotypes (T1–T23). In some cases, however, the resolution of 18S is limited, and other genetic markers could be useful for unravelling poorly resolved lineages. In this study, the partial large subunit (LSU) of rDNA and ITS were used to re-examine the Acanthamoeba palestinensis group (T2/T6 lineage), which consists of various poorly defined lineages, including the T2 and T6 genotypes. New sequences overlapping 18S, ITS, and LSU were recovered. The analysis placed previously identified partial ITS-LSU sequences as T2/T6 and further confirmed the separation of the OX1 lineage from T2. In addition, analysis of the second internal transcribed spacer (ITS-2) suggests that multiple species may be present within the T6 and OX1 lineages. The results obtained from the T2/T6 lineage analysis confirm the utility of partial LSU and ITS for the study of Acanthamoeba, suggesting their advantage for disentangling complex lineages.

European Journal of Protistology, 2024

Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of ... more Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both A. castellanii and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, Acanthamoeba terricola Pussard, 1964, but both were successively synonymized with A. castellanii. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in Acanthamoeba, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of A. castellanii. In this study, we compared the type strain of A. terricola with the Neff strain and A. castellanii, and analysed the available molecular data including new sequences obtained from A. terricola. Here we provide molecular evidence to validate the species A. terricola. The Neff strain is therefore transferred to A. terricola and should no longer be considered as belonging to A. castellanii.

Microorganisms, Apr 26, 2024

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The Journal of Infectious Diseases, Nov 1, 2000

Journal of Biomedical Research & Environmental Sciences

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

Parasitology Research

Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected... more Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected with fungi. Upon plate culture, amoeba-trapping hyphal filaments were developed, and the amoeba trophozoites were found to harbour yeast-like parasites in their cytoplasm. Transfection of hyphae to a laboratory strain of Vannella resulted in the formation of conidia indicating the possible presence of zygomycetes of the genus Acaulopage, while efforts to culture the endoparasite remained unsuccessful. Biomolecular analysis based on rDNA revealed the presence of two distinct types of fungi, confirming the filamentous form as Acaulopage sp. (Zoopagomycota, Zoopagales) and identifying the yeast-like endoparasite as Cladosporium sp. (Ascomycota, Cladosporiales). To our knowledge, this is the first report of amoebae infected with Cladosporium.

Parasitol Res, 2023

Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected... more Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected with fungi. Upon plate culture, amoeba-trapping hyphal filaments were developed, and the amoeba trophozoites were found to harbour yeast-like parasites in their cytoplasm. Transfection of hyphae to a laboratory strain of Vannella resulted in the formation of conidia indicating the possible presence of zygomycetes of the genus Acaulopage, while efforts to culture the endoparasite remained unsuccessful. Biomolecular analysis based on rDNA revealed the presence of two distinct types of fungi, confirming the filamentous form as Acaulopage sp. (Zoopagomycota, Zoopagales) and identifying the yeast-like endoparasite as Cladosporium sp. (Ascomycota, Cladosporiales). To our knowledge, this is the first report of amoebae infected with Cladosporium.

J. Biomed. Res. Environ. Sci., 2023

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

J. Biomed. Res. Environ. Sci., 2023

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

This article cites 194 articles, 98 of which can be accessed free at:

European Journal of Protistology, 2018

Various strains belonging to three Acanthamoeba species, A. griffini (genotype T3), A. lenticulat... more Various strains belonging to three Acanthamoeba species, A. griffini (genotype T3), A. lenticulata (T5), and A. jacobsi (T15), have group I introns in their 18S rRNA genes. Group I introns are self-splicing ribozymes that can spread among host lineages either through an intron-encoded endonuclease at the DNA level, or by reverse splicing during the RNA cycle. In Acanthamoeba, introns belong to the subclass IC1, they are located at one out four positions within the rRNA, show low identity values and all lack open reading frames to encode for an endonuclease. Uncharacterized introns from strains of another genotype, T4 (A. castellanii complex), resemble those of genotype T3, and at least one of them contains a non-functional endonuclease gene. Here, we analyzed all available data on Acanthamoeba 18S rDNA sequences to identify the possible presence of open reading frames that could encode endonucleases. We found a total of eight 18S rDNA sequences, all from T4 strains, that have introns containing putative non-functional endonuclease genes. Furthermore, two distinct endonucleases can be identified that are differently inserted in unrelated introns.

Microorganisms

Acanthamoeba is a ubiquitous free-living amoeba capable of being an opportunistic pathogen in hum... more Acanthamoeba is a ubiquitous free-living amoeba capable of being an opportunistic pathogen in humans and animals. A critical step in infection is the adhesion of the amoeba to host cells and tissues, and two major parasite adhesins, mannose-binding protein (MBP) and laminin-binding protein (LBP), are known to recognize the cell surface glycoproteins and those of the extracellular matrix, respectively. In this study, the available genomes of Acanthamoeba were analysed to recover the sequences of MBP and LBP using previously published genetic data. Genes for both proteins were successfully obtained from strains belonging to various genotypes (T4A, T4D, T4G, T4F, T2, T5, T10, T22, T7 and T18), resulting in a single gene for LBP but identifying two types of MBP, MBP1 and MBP2. Phylogenetic analysis based on deduced amino acid sequences shows that both MBP and LBP have a branching pattern that is consistent with that based on 18S rDNA, indicating that changes in both proteins occurred du...

Experientia supplementum, 2022

Microsporidia have drastically modified genomes and cytology resulting from their high level of a... more Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.

Microorganisms

The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiqui... more The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiquitous free-living amoeba, are largely based on the analysis of 18S rDNA sequences, currently delineating 23 genotypes, T1 to T23. In this study, the sequences of the ITS region, i.e., the 5.8S rDNA and the two internal transcribed spacers (ITS-1 and ITS-2), and those of the large subunit (LSU) rDNA of Acanthamoeba were recovered from amoeba genomes; the sequences are available in GenBank. The complete ITS–LSU sequences could be obtained for 15 strains belonging to 7 distinct lineages (T4A, T4D, T4F, T4G, T2, T5, and T18), and the site of the hidden break producing the 26Sα and 26Sβ was identified. For the other lines, either the LSU is partial (T2/T6, T7) or the ITS is fragmentary (T7, T10, T22). It is noteworthy that a number of sequences assigned to fungi turned out to actually be Acanthamoeba, only some of which could be affiliated with known genotypes. Analysis of the obtained sequenc...

Exp Suppl. 2022;114:71-90., 2022

Microsporidia have drastically modified genomes and cytology resulting from their high level of a... more Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.

Microorganisms, 2022

The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiqui... more The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiquitous free-living amoeba, are largely based on the analysis of 18S rDNA sequences, currently delineating 23 genotypes, T1 to T23. In this study, the sequences of the ITS region, i.e., the 5.8S rDNA and the two internal transcribed spacers (ITS-1 and ITS-2), and those of the large subunit (LSU) rDNA of Acanthamoeba were recovered from amoeba genomes and sequences available in GenBank. The complete ITS-LSU sequences could be obtained for 15 strains belonging to 7 distinct lineages (T4A, T4D, T4F, T4G, T2, T5, T18), and the site of the hidden break producing the 26S and 26S was identified. For other lines, either the LSU is partial (T2/T6, T7) or the ITS is fragmentary (T7, T10, T22). It is noteworthy that a number of sequences assigned to fungi turned out to actually be Acanthamoeba, only some of which could be affiliated with known genotypes. Analysis of the obtained sequences indicates that both ITS and LSU are promising for diagnostic and phylogenetic purposes.

Parasitology Research

Group 1 acanthamoebae are morphologically and phylogenetically distinct from all other Acanthamoe... more Group 1 acanthamoebae are morphologically and phylogenetically distinct from all other Acanthamoeba species. They include five species, each labelled by its genotype: A. astronyxis (T7), A. tubiashi (T8), A. comandoni (T9), unnamed Acanthamoeba sp. (T17), and A. byersi (T18). Thought only environmental, they have recently attracted attention due to their recovery in cases of human keratitis and encephalitis, the main diseases caused by Acanthamoeba, where the usual causative agents are mainly species of Groups 2 and 3. Analysis of the available data confirms the pathogenic importance of these species, although it is probably minor compared to that of the species in Groups 2 and 3. In addition, it should be noted that there are difficulties in identifying genotypes by widely used molecular methods, and some misidentifications are revealed.

European journal of protistology, Jun 1, 2024

Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of ... more Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both A. castellanii and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, Acanthamoeba terricola Pussard, 1964, but both were successively synonymized with A. castellanii. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in Acanthamoeba, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of A. castellanii. In this study, we compared the type strain of A. terricola with the Neff strain and A. castellanii, and analysed the available molecular data including new sequences obtained from A. terricola. Here we provide molecular evidence to validate the species A. terricola. The Neff strain is therefore transferred to A. terricola and should no longer be considered as belonging to A. castellanii.

Microorganisms, 2024

The molecular classification of Acanthamoeba is currently based on the analysis of 18S rDNA seque... more The molecular classification of Acanthamoeba is currently based on the analysis of 18S rDNA sequences, delimiting around twenty genotypes (T1–T23). In some cases, however, the resolution of 18S is limited, and other genetic markers could be useful for unravelling poorly resolved lineages. In this study, the partial large subunit (LSU) of rDNA and ITS were used to re-examine the Acanthamoeba palestinensis group (T2/T6 lineage), which consists of various poorly defined lineages, including the T2 and T6 genotypes. New sequences overlapping 18S, ITS, and LSU were recovered. The analysis placed previously identified partial ITS-LSU sequences as T2/T6 and further confirmed the separation of the OX1 lineage from T2. In addition, analysis of the second internal transcribed spacer (ITS-2) suggests that multiple species may be present within the T6 and OX1 lineages. The results obtained from the T2/T6 lineage analysis confirm the utility of partial LSU and ITS for the study of Acanthamoeba, suggesting their advantage for disentangling complex lineages.

European Journal of Protistology, 2024

Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of ... more Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both A. castellanii and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, Acanthamoeba terricola Pussard, 1964, but both were successively synonymized with A. castellanii. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in Acanthamoeba, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of A. castellanii. In this study, we compared the type strain of A. terricola with the Neff strain and A. castellanii, and analysed the available molecular data including new sequences obtained from A. terricola. Here we provide molecular evidence to validate the species A. terricola. The Neff strain is therefore transferred to A. terricola and should no longer be considered as belonging to A. castellanii.

Microorganisms, Apr 26, 2024

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The Journal of Infectious Diseases, Nov 1, 2000

Journal of Biomedical Research & Environmental Sciences

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

Parasitology Research

Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected... more Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected with fungi. Upon plate culture, amoeba-trapping hyphal filaments were developed, and the amoeba trophozoites were found to harbour yeast-like parasites in their cytoplasm. Transfection of hyphae to a laboratory strain of Vannella resulted in the formation of conidia indicating the possible presence of zygomycetes of the genus Acaulopage, while efforts to culture the endoparasite remained unsuccessful. Biomolecular analysis based on rDNA revealed the presence of two distinct types of fungi, confirming the filamentous form as Acaulopage sp. (Zoopagomycota, Zoopagales) and identifying the yeast-like endoparasite as Cladosporium sp. (Ascomycota, Cladosporiales). To our knowledge, this is the first report of amoebae infected with Cladosporium.

Parasitol Res, 2023

Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected... more Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected with fungi. Upon plate culture, amoeba-trapping hyphal filaments were developed, and the amoeba trophozoites were found to harbour yeast-like parasites in their cytoplasm. Transfection of hyphae to a laboratory strain of Vannella resulted in the formation of conidia indicating the possible presence of zygomycetes of the genus Acaulopage, while efforts to culture the endoparasite remained unsuccessful. Biomolecular analysis based on rDNA revealed the presence of two distinct types of fungi, confirming the filamentous form as Acaulopage sp. (Zoopagomycota, Zoopagales) and identifying the yeast-like endoparasite as Cladosporium sp. (Ascomycota, Cladosporiales). To our knowledge, this is the first report of amoebae infected with Cladosporium.

J. Biomed. Res. Environ. Sci., 2023

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

J. Biomed. Res. Environ. Sci., 2023

During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA... more During an investigation of amoeba rDNA sequences, a group I intron was identified in the 18S rDNA of Thecamoeba aesculea (Amoebozoa; Discosea) at position S956. Secondary structure of Thecamoeba intron and phylogenetic analysis suggest that it is affiliated with other S956 introns occurring in distantly related amoebae such as acrasid (Percolozoa; Heterolobosea) and myxogastrid (Amoebozoa; Mycetozoa) slime moulds. This is the first report of a nuclear intron occurring within the genus Thecamoeba.

This article cites 194 articles, 98 of which can be accessed free at:

European Journal of Protistology, 2018

Various strains belonging to three Acanthamoeba species, A. griffini (genotype T3), A. lenticulat... more Various strains belonging to three Acanthamoeba species, A. griffini (genotype T3), A. lenticulata (T5), and A. jacobsi (T15), have group I introns in their 18S rRNA genes. Group I introns are self-splicing ribozymes that can spread among host lineages either through an intron-encoded endonuclease at the DNA level, or by reverse splicing during the RNA cycle. In Acanthamoeba, introns belong to the subclass IC1, they are located at one out four positions within the rRNA, show low identity values and all lack open reading frames to encode for an endonuclease. Uncharacterized introns from strains of another genotype, T4 (A. castellanii complex), resemble those of genotype T3, and at least one of them contains a non-functional endonuclease gene. Here, we analyzed all available data on Acanthamoeba 18S rDNA sequences to identify the possible presence of open reading frames that could encode endonucleases. We found a total of eight 18S rDNA sequences, all from T4 strains, that have introns containing putative non-functional endonuclease genes. Furthermore, two distinct endonucleases can be identified that are differently inserted in unrelated introns.

Microorganisms

Acanthamoeba is a ubiquitous free-living amoeba capable of being an opportunistic pathogen in hum... more Acanthamoeba is a ubiquitous free-living amoeba capable of being an opportunistic pathogen in humans and animals. A critical step in infection is the adhesion of the amoeba to host cells and tissues, and two major parasite adhesins, mannose-binding protein (MBP) and laminin-binding protein (LBP), are known to recognize the cell surface glycoproteins and those of the extracellular matrix, respectively. In this study, the available genomes of Acanthamoeba were analysed to recover the sequences of MBP and LBP using previously published genetic data. Genes for both proteins were successfully obtained from strains belonging to various genotypes (T4A, T4D, T4G, T4F, T2, T5, T10, T22, T7 and T18), resulting in a single gene for LBP but identifying two types of MBP, MBP1 and MBP2. Phylogenetic analysis based on deduced amino acid sequences shows that both MBP and LBP have a branching pattern that is consistent with that based on 18S rDNA, indicating that changes in both proteins occurred du...

Experientia supplementum, 2022

Microsporidia have drastically modified genomes and cytology resulting from their high level of a... more Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.

Microorganisms

The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiqui... more The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiquitous free-living amoeba, are largely based on the analysis of 18S rDNA sequences, currently delineating 23 genotypes, T1 to T23. In this study, the sequences of the ITS region, i.e., the 5.8S rDNA and the two internal transcribed spacers (ITS-1 and ITS-2), and those of the large subunit (LSU) rDNA of Acanthamoeba were recovered from amoeba genomes; the sequences are available in GenBank. The complete ITS–LSU sequences could be obtained for 15 strains belonging to 7 distinct lineages (T4A, T4D, T4F, T4G, T2, T5, and T18), and the site of the hidden break producing the 26Sα and 26Sβ was identified. For the other lines, either the LSU is partial (T2/T6, T7) or the ITS is fragmentary (T7, T10, T22). It is noteworthy that a number of sequences assigned to fungi turned out to actually be Acanthamoeba, only some of which could be affiliated with known genotypes. Analysis of the obtained sequenc...

Exp Suppl. 2022;114:71-90., 2022

Microsporidia have drastically modified genomes and cytology resulting from their high level of a... more Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.

Microorganisms, 2022

The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiqui... more The identification and classification of strains of Acanthamoeba, a potentially pathogenic ubiquitous free-living amoeba, are largely based on the analysis of 18S rDNA sequences, currently delineating 23 genotypes, T1 to T23. In this study, the sequences of the ITS region, i.e., the 5.8S rDNA and the two internal transcribed spacers (ITS-1 and ITS-2), and those of the large subunit (LSU) rDNA of Acanthamoeba were recovered from amoeba genomes and sequences available in GenBank. The complete ITS-LSU sequences could be obtained for 15 strains belonging to 7 distinct lineages (T4A, T4D, T4F, T4G, T2, T5, T18), and the site of the hidden break producing the 26S and 26S was identified. For other lines, either the LSU is partial (T2/T6, T7) or the ITS is fragmentary (T7, T10, T22). It is noteworthy that a number of sequences assigned to fungi turned out to actually be Acanthamoeba, only some of which could be affiliated with known genotypes. Analysis of the obtained sequences indicates that both ITS and LSU are promising for diagnostic and phylogenetic purposes.

Parasitology Research

Group 1 acanthamoebae are morphologically and phylogenetically distinct from all other Acanthamoe... more Group 1 acanthamoebae are morphologically and phylogenetically distinct from all other Acanthamoeba species. They include five species, each labelled by its genotype: A. astronyxis (T7), A. tubiashi (T8), A. comandoni (T9), unnamed Acanthamoeba sp. (T17), and A. byersi (T18). Thought only environmental, they have recently attracted attention due to their recovery in cases of human keratitis and encephalitis, the main diseases caused by Acanthamoeba, where the usual causative agents are mainly species of Groups 2 and 3. Analysis of the available data confirms the pathogenic importance of these species, although it is probably minor compared to that of the species in Groups 2 and 3. In addition, it should be noted that there are difficulties in identifying genotypes by widely used molecular methods, and some misidentifications are revealed.