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Hilda F J Pena - One of the best experts on this subject based on the ideXlab platform.
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Crab-eating fox (Cerdocyon thous), a South American canid, as a definitive host for Hammondia heydorni.
Veterinary parasitology, 2009Co-Authors: Rodrigo M. Soares, Michelle Klein Sercundes, Lara Borges Keid, Luiz R P B Cortez, Solange M Gennari, Hilda F J PenaAbstract:Hammondia heydorni is a cyst forming coccidia closely related to other apicomplexans, such as Toxoplasma gondii, Neospora caninum and Hammondia hammondi with a two-host life cycle. Dogs and other canids as red foxes (Vulpes vulpes) and coyotes (Canis latrans) may serve as definitive hosts for H. heydorni. Sporulated oocysts are infective for cattle, sheep and goats, which may serve as intermediate hosts. Herein, we describe the ability of crab-eating fox (Cerdocyon thous), a wild carnivore that is commonly found from northern Argentina to northern South America, to serve as definitive host of H. heydorni. The whole masseter muscle and brain from two 2-year-old bovines were collected, minced and pooled together for the fox infection. The bovine pooled tissues were equally administered to four foxes, in two consecutive days. Two foxes shed subspherical unsporulated oocysts measuring 10-15microm, after 8 and 9 days post-infection, respectively. One of the foxes eliminated oocysts for 5 days, while the other fox shed oocysts for 9 days. A DNA sample of oocysts detected at each day of oocyst elimination was tested by two PCRs, one of them carried out employing primers directed to the common toxoplasmatiid 18S and 5.8S Ribosomal RNA coding genes (PCR-ITS1) and the other based on heat-shock protein 70kDa coding gene (PCR-HSP70). These samples were also submitted to a N. caninum specific nested-PCR protocol based on a N. caninum specific gene (Nc5-nPCR). All of them were positive by PCR-ITS1 and PCR-HSP70 but negative by Nc5-nPCR. The PCR-ITS1 and PCR-HSP70 nucleotide sequences amplified from the oocysts shed by the foxes revealed 100% identity with homologous sequences of H. heydorni. In conclusion, it is clear that H. heydorni also uses the crab-eating fox as a definitive host. The crab-eating fox is usually reported to live in close contact with livestock in several regions of Brazil. Therefore, it is reasonable to infer that such carnivores may play an important role in the sylvatic and domestic cycles of H. heydorni infection.
Elena Conti - One of the best experts on this subject based on the ideXlab platform.
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structural analysis reveals the characteristic features of mtr4 a dexh helicase involved in nuclear RNA processing and surveillance
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: John R Weir, Fabien Bonneau, Jendrik Hentschel, Elena ContiAbstract:Mtr4 is a conserved RNA helicase that functions together with the nuclear exosome. It participates in the processing of structured RNAs, including the maturation of 5.8S Ribosomal RNA (rRNA). It also interacts with the polyadenylating Trf4-Air2 heterodimer to form the so-called TRAMP (Trf4-Air2-Mtr4 Polyadenylation) complex. TRAMP is involved in exosome-mediated degradation of aberrant RNAs in nuclear surveillance pathways. We report the 2.9-A resolution crystal structure of Saccharomyces cerevisiae Mtr4 in complex with ADP and RNA. The structure shows a central ATPase core similar to that of other DExH helicases. Inserted in the DExH core is a region characteristic of Mtr4 orthologues that folds into an elongated stalk connected to a β-barrel domain. This domain shows unexpected similarity to the KOW domain of L24, a Ribosomal protein that binds 23S rRNA. We find that indeed the KOW domain of Mtr4 is able to bind in vitro transcribed tRNA iMet , suggesting it might assist in presenting RNA substrates to the helicase core. The interaction of Mtr4 with Trf4-Air2 is mediated not by the stalk/KOW insertion but by the DExH core. We find that in the context of the TRAMP complex, the DExH core functions independently in vitro as an RNA helicase and a protein-binding platform. Mtr4 has thus evolved specific structural and surface features to perform its multiple functions.
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structural analysis reveals the characteristic features of mtr4 a dexh helicase involved in nuclear RNA processing and surveillance
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: John R Weir, Fabien Bonneau, Jendrik Hentschel, Elena ContiAbstract:Mtr4 is a conserved RNA helicase that functions together with the nuclear exosome. It participates in the processing of structured RNAs, including the maturation of 5.8S Ribosomal RNA (rRNA). It also interacts with the polyadenylating Trf4-Air2 heterodimer to form the so-called TRAMP (Trf4-Air2-Mtr4 Polyadenylation) complex. TRAMP is involved in exosome-mediated degradation of aberrant RNAs in nuclear surveillance pathways. We report the 2.9-A resolution crystal structure of Saccharomyces cerevisiae Mtr4 in complex with ADP and RNA. The structure shows a central ATPase core similar to that of other DExH helicases. Inserted in the DExH core is a region characteristic of Mtr4 orthologues that folds into an elongated stalk connected to a beta-barrel domain. This domain shows unexpected similarity to the KOW domain of L24, a Ribosomal protein that binds 23S rRNA. We find that indeed the KOW domain of Mtr4 is able to bind in vitro transcribed tRNA(iMet), suggesting it might assist in presenting RNA substrates to the helicase core. The interaction of Mtr4 with Trf4-Air2 is mediated not by the stalk/KOW insertion but by the DExH core. We find that in the context of the TRAMP complex, the DExH core functions independently in vitro as an RNA helicase and a protein-binding platform. Mtr4 has thus evolved specific structural and surface features to perform its multiple functions.
Rodrigo M. Soares - One of the best experts on this subject based on the ideXlab platform.
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Crab-eating fox (Cerdocyon thous), a South American canid, as a definitive host for Hammondia heydorni.
Veterinary parasitology, 2009Co-Authors: Rodrigo M. Soares, Michelle Klein Sercundes, Lara Borges Keid, Luiz R P B Cortez, Solange M Gennari, Hilda F J PenaAbstract:Hammondia heydorni is a cyst forming coccidia closely related to other apicomplexans, such as Toxoplasma gondii, Neospora caninum and Hammondia hammondi with a two-host life cycle. Dogs and other canids as red foxes (Vulpes vulpes) and coyotes (Canis latrans) may serve as definitive hosts for H. heydorni. Sporulated oocysts are infective for cattle, sheep and goats, which may serve as intermediate hosts. Herein, we describe the ability of crab-eating fox (Cerdocyon thous), a wild carnivore that is commonly found from northern Argentina to northern South America, to serve as definitive host of H. heydorni. The whole masseter muscle and brain from two 2-year-old bovines were collected, minced and pooled together for the fox infection. The bovine pooled tissues were equally administered to four foxes, in two consecutive days. Two foxes shed subspherical unsporulated oocysts measuring 10-15microm, after 8 and 9 days post-infection, respectively. One of the foxes eliminated oocysts for 5 days, while the other fox shed oocysts for 9 days. A DNA sample of oocysts detected at each day of oocyst elimination was tested by two PCRs, one of them carried out employing primers directed to the common toxoplasmatiid 18S and 5.8S Ribosomal RNA coding genes (PCR-ITS1) and the other based on heat-shock protein 70kDa coding gene (PCR-HSP70). These samples were also submitted to a N. caninum specific nested-PCR protocol based on a N. caninum specific gene (Nc5-nPCR). All of them were positive by PCR-ITS1 and PCR-HSP70 but negative by Nc5-nPCR. The PCR-ITS1 and PCR-HSP70 nucleotide sequences amplified from the oocysts shed by the foxes revealed 100% identity with homologous sequences of H. heydorni. In conclusion, it is clear that H. heydorni also uses the crab-eating fox as a definitive host. The crab-eating fox is usually reported to live in close contact with livestock in several regions of Brazil. Therefore, it is reasonable to infer that such carnivores may play an important role in the sylvatic and domestic cycles of H. heydorni infection.
Yuzaburo Ishida - One of the best experts on this subject based on the ideXlab platform.
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analysis of alexandrium dinophyceae species using sequences of the 5.8S Ribosomal dna and inteRNAl transcribed spacer regions
Journal of Phycology, 1996Co-Authors: Masao Adachi, Yoshihiko Sake, Yuzaburo IshidaAbstract:The 5.8S Ribosomal RNA gene (rDNA) and flanking inteRNAl transcribed spacers 1 and 2 (ITS1 and ITS2) from 7 isolates of Alexandrium catenella (Wedon et Kofoid) Taylor, 13 isolates of A. tamarense (Lebour) Balech, 2 isolates of A. affine (Fukuyo et Inoue) Balech, and single isolates of A. fundyense Balech, A. insuetum Balech, and A. pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo comb. nov. from Japan, Thailand, and the United States were amplified using the polymerase chain reaction (PCR), sequenced, and subjected to phylogenetic analysis. The sequences ranged from 518 to 535 base pairs (bp) exclusive of the 18S and 28S rDNA coding regions. Sequence comparisons revealed seven divergent “ITS types” designated as follows: 1) catenella type, 2) tamarense type, 3) WKS-1 type, 4) Thai type, 5) affine type, 6) insuetum type, and 7) pseudogonyaulax type. Isolates of the tamarense type from various locations in Japan and the United States and of A. fundyense from the United States were closely related to each other and were clearly divergent from isolates of A. tamarense WKS-1 (WKS-I type) or A. tamarense CU-15 (Thai type). These latter two strains carried unique ITS types, although they were not distinguishable from isolates of the tamarense type by morphological criteria. Distance values between isolates of the tamarense type and the WKS-1 or Thai type were quite high (about 0.21 and 0.39, respectively). Seven isolates of A. catenella from Japan (catenella type) clearly diverged from the other ITS types already mentioned. Distance values between isolates of the catenella type were extremely low (<0.01), whereas distance values of ITS between the catenella type and the tamarense, WKS-1, or Thai type were 0.17, 0.18, and 0.40, respectively. Isolates of A. affine, A. insuetum, and A. pseudogonyaulax all carried unique ITS types. The ITSs of the tamarense type exhibited two distinct ITS sets, the “A gene” and the “B gene.” The two sequences occurred in a 1:1 ratio in PCR products. In contrast, the ITSs of all other isolates appeared homogeneous. Sequence comparisons also showed that the variations in the 3′ end of ITS1 (150-177 bp) were low within each ITS type but extremely high between ITS types. The number of different nucleotides among the seven Alexandrium types in this 28-bp region is more than 10. High diversity of this region may facilitate the design of DNA probes specific for each ITS type/species of Alexandrium.
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restriction fragment length polymorphism of Ribosomal dna inteRNAl transcribed spacer and 5.8S regions in japanese alexandrium species dinophyceae 1
Journal of Phycology, 1994Co-Authors: Masao Adachi, Yoshihiko Sako, Yuzaburo IshidaAbstract:The 5.8S Ribosomal RNA (rDNA) gene and flanking inteRNAl transcribed spacers (ITS1 and ITS2)from 9 isolates of Alexandrium catenella (Whedon and Kofoid) Taylor, 11 isolates of A. tamarense (Lebour) Taylor, and single isolates of A. affine (Inoue et Fukuyo) Balech, A. insuetum Balech, and A. pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo comb. nov. from various locations in Japan were amplified using the polymerase chain reaction (PCR) and subjected to restriction fragment-length polymorphism (RFLP) analysis. PCR products from all strains were approximately 610 bp, inclusive of a limited region of the 18S and 28S rRNA coding regions. RFLP analysis using four restriction enzymes revealed six distinct classes of rDNA (“ITS types”). Restriction patterns of A. catenella were uniform at the intra-specific level and clearly distinguishable from those of A. tamarense. The patterns associated with A. tamarense (“tamarense group”) were also uniform except for one strain, WKS-1. Some restriction fragments from WKS-1 were in common with those of A. catenella or A. tamarense, whereas some were distinct from all Alexandrium species tested. Alexandrium affine, A. insuetum, and A. pseudogonyaulax carry unique ITS types. The ITSs of the “tamarense group” exhibit sequence heterogeneity. In contrast, the ITSs of all other isolates (including WKS-1) appear homogeneous. RFLP analysis of the 5.8S rDNA and flanking ITSs regions from Alexandrium species reveals useful taxonomic and genetic markers at the species and/or population levels.
John R Weir - One of the best experts on this subject based on the ideXlab platform.
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structural analysis reveals the characteristic features of mtr4 a dexh helicase involved in nuclear RNA processing and surveillance
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: John R Weir, Fabien Bonneau, Jendrik Hentschel, Elena ContiAbstract:Mtr4 is a conserved RNA helicase that functions together with the nuclear exosome. It participates in the processing of structured RNAs, including the maturation of 5.8S Ribosomal RNA (rRNA). It also interacts with the polyadenylating Trf4-Air2 heterodimer to form the so-called TRAMP (Trf4-Air2-Mtr4 Polyadenylation) complex. TRAMP is involved in exosome-mediated degradation of aberrant RNAs in nuclear surveillance pathways. We report the 2.9-A resolution crystal structure of Saccharomyces cerevisiae Mtr4 in complex with ADP and RNA. The structure shows a central ATPase core similar to that of other DExH helicases. Inserted in the DExH core is a region characteristic of Mtr4 orthologues that folds into an elongated stalk connected to a β-barrel domain. This domain shows unexpected similarity to the KOW domain of L24, a Ribosomal protein that binds 23S rRNA. We find that indeed the KOW domain of Mtr4 is able to bind in vitro transcribed tRNA iMet , suggesting it might assist in presenting RNA substrates to the helicase core. The interaction of Mtr4 with Trf4-Air2 is mediated not by the stalk/KOW insertion but by the DExH core. We find that in the context of the TRAMP complex, the DExH core functions independently in vitro as an RNA helicase and a protein-binding platform. Mtr4 has thus evolved specific structural and surface features to perform its multiple functions.
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structural analysis reveals the characteristic features of mtr4 a dexh helicase involved in nuclear RNA processing and surveillance
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: John R Weir, Fabien Bonneau, Jendrik Hentschel, Elena ContiAbstract:Mtr4 is a conserved RNA helicase that functions together with the nuclear exosome. It participates in the processing of structured RNAs, including the maturation of 5.8S Ribosomal RNA (rRNA). It also interacts with the polyadenylating Trf4-Air2 heterodimer to form the so-called TRAMP (Trf4-Air2-Mtr4 Polyadenylation) complex. TRAMP is involved in exosome-mediated degradation of aberrant RNAs in nuclear surveillance pathways. We report the 2.9-A resolution crystal structure of Saccharomyces cerevisiae Mtr4 in complex with ADP and RNA. The structure shows a central ATPase core similar to that of other DExH helicases. Inserted in the DExH core is a region characteristic of Mtr4 orthologues that folds into an elongated stalk connected to a beta-barrel domain. This domain shows unexpected similarity to the KOW domain of L24, a Ribosomal protein that binds 23S rRNA. We find that indeed the KOW domain of Mtr4 is able to bind in vitro transcribed tRNA(iMet), suggesting it might assist in presenting RNA substrates to the helicase core. The interaction of Mtr4 with Trf4-Air2 is mediated not by the stalk/KOW insertion but by the DExH core. We find that in the context of the TRAMP complex, the DExH core functions independently in vitro as an RNA helicase and a protein-binding platform. Mtr4 has thus evolved specific structural and surface features to perform its multiple functions.