RESUMO
Caenorhabditis elegans is a free-living nematode, belonging to the bacterivorous trophic group. Although it was cited in several countries, in different types of ecosystems and in associations with other organisms, the wild habitats of this nematode have not yet been precisely defined. In Argentina, C. elegans was recently isolated from the hoverfly Allograpta exotica, a voracious predator with potential biological control against aphids in horticultural crops. In this frame, the objectives of this study were (i) to characterize it molecularly and morphologically (ii) to report a wild strain of C. elegans for the first time from Argentina, (iii) to present a new ecological niche by associating it with A. exotica and (iv) to evaluate the pathogenicity against these insects. The results of the morphological and molecular analyses made it possible to determine that the isolated nematode was C. elegans, thus establishing the ARGLP1900 wild strain as the first record of this nematode for Argentina. A new association was described, since there are no records of interaction between C. elegans and A. exotica, providing information on a new ecological niche. The new wild strain found in this work, could be appropriate for comparative genomic studies with other C. elegans strains.
Assuntos
Caenorhabditis elegans , Animais , Afídeos , Argentina , Caenorhabditis elegans/genética , Dípteros , Ecossistema , VirulênciaRESUMO
When subjected to molecular study, species of digeneans believed to be cosmopolitan are usually found to consist of complexes of species with narrower distributions. We present molecular and morphological evidence of transcontinental distributions in two species of Apharyngostrigea Ciurea, 1924, based on samples from Africa and the Americas. Sequences of cytochrome c oxidase I and, in some samples, internal transcribed spacer, revealed Apharyngostrigea pipientis (Faust, 1918) in Tanzania (first known African record), Argentina, Brazil, USA and Canada. Sequences from A. pipientis also match previously published sequences identified as Apharyngostrigea cornu (Zeder, 1800) originating in Mexico. Hosts of A. pipientis surveyed include definitive hosts from the Afrotropic, Neotropic and Nearctic, as well as first and second intermediate hosts from the Americas, including the type host and type region. In addition, metacercariae of A. pipientis were obtained from experimentally infected Poecilia reticulata, the first known record of this parasite in a non-amphibian second intermediate host. Variation in cytochrome c oxidase I haplotypes in A. pipientis is consistent with a long established, wide-ranging species with moderate genetic structure among Nearctic, Neotropic and Afrotropic regions. We attribute this to natural dispersal by birds and find no evidence of anthropogenic introductions of exotic host species. Sequences of CO1 and ITS from adult Apharyngostrigea simplex (Johnston, 1904) from Egretta thula in Argentina matched published data from cercariae from Biomphalaria straminea from Brazil and metacercariae from Cnesterodon decemmaculatus in Argentina, consistent with previous morphological and life-cycle studies reporting this parasite-originally described in Australia-in South America. Analyses of the mitochondrial genome and rDNA operon from A. pipientis support prior phylogenies based on shorter markers showing the Strigeidae Railliet, 1919 to be polyphyletic.
Assuntos
Trematódeos , Infecções por Trematódeos , Animais , Brasil , Genômica , Estágios do Ciclo de Vida , Filogenia , Trematódeos/genética , Infecções por Trematódeos/veterináriaRESUMO
A mermithid nematode was found parasitizing nymphs of dragonflies and damselflies. The host specimens were collected from the stream Cajaravilla, Magdalena, Buenos Aires state, Argentina. In this work, we described Amphimermis enzoni n. sp., a nematode new to science. Nematodes were identified through morphological and molecular methods. The combination of the following characters separates A. enzoni n. sp. from other members of the genus Amphimermis Steiner: long and S-shaped vagina, twisted spicules for proximal 34% of their length, untwisted for 12%, again twisted for 30%, and untwisted for the last 24%; genital papillae arranged in three rows, medial row marginally longer than sub-medial rows; medial row bifurcated immediately anterior and posterior to cloaca, with 111 genital papillae (73 pre-anals and 38 post-anals). The sequences of 18S rDNA regions from A. enzoni formed a well-supported monophyletic clade with two GenBank sequences of Amphimermis spp. (EF617354 and EF617355) with 0.63 to 1.26% divergence and two Mermithidae spp. (LC512371 and LC512370) with 0.63 to 1.1% divergence, respectively. To our knowledge, this is the first example of mermithid infection in nymphs of dragonflies and damselflies for South America.A mermithid nematode was found parasitizing nymphs of dragonflies and damselflies. The host specimens were collected from the stream Cajaravilla, Magdalena, Buenos Aires state, Argentina. In this work, we described Amphimermis enzoni n. sp., a nematode new to science. Nematodes were identified through morphological and molecular methods. The combination of the following characters separates A. enzoni n. sp. from other members of the genus Amphimermis Steiner: long and S-shaped vagina, twisted spicules for proximal 34% of their length, untwisted for 12%, again twisted for 30%, and untwisted for the last 24%; genital papillae arranged in three rows, medial row marginally longer than sub-medial rows; medial row bifurcated immediately anterior and posterior to cloaca, with 111 genital papillae (73 pre-anals and 38 post-anals). The sequences of 18S rDNA regions from A. enzoni formed a well-supported monophyletic clade with two GenBank sequences of Amphimermis spp. (EF617354 and EF617355) with 0.63 to 1.26% divergence and two Mermithidae spp. (LC512371 and LC512370) with 0.63 to 1.1% divergence, respectively. To our knowledge, this is the first example of mermithid infection in nymphs of dragonflies and damselflies for South America.
RESUMO
Oxyurid nematodes parasitizing the mole cricket Neoscapteriscus vicinus were isolated in the framework of sampling fields of mole-crickets from the pampean region, in Argentina. In this work, molecular characterization of the 18S rRNA partial sequence of nematodes belonging to the families Thelastomatidae (Cameronia arecoensis Marchissio and Miralles 1987) and Travassosinematidae (Binema korsakowi Sergiev 1923 and Binema klossae, Marchissio and Miralles 1993) were carried out. This is the first world report of sequences belonging to B. klossae and C. arecoensis and first Argentinian report of B. korsakowi sequence. Also, morphological and morphometric features of B. klossae, B. korsakowi and C. arecoensis from Argentinian populations are reported.
Assuntos
Gryllidae/parasitologia , Oxyurida/genética , RNA Ribossômico 18S/genética , Animais , Argentina , Feminino , Gryllidae/classificação , Masculino , Oxyurida/classificação , Oxyurida/isolamento & purificaçãoRESUMO
Thelastomatidae is one of the largest families parasitizing insects, within the order Oxyurida. In this work we reported parasitism in nymphs and adults of Neocurtilla claraziana by two different thelastomatid species as a part of a field survey on agricultural pests. Nymphs and adults of this insect were isolated from grasslands of Buenos Aires State, Argentina using a tensio-active solution. The nematode species Gryllophila skrjabini Sergiev, 1923 and Cephalobellus magalhaesi Schwenk, 1926 are briefly described and measurements are given. Both nematodes are reported for the first time in Argentina with C. magalhaesi being the second isolation of this species in the world. Neocurtilla clarziana is a new host record for G. skrjabini.
Thelastomatidae es una de las principales familias que parasitan insectos, dentro del orden Oxyurida. En este trabajo informamos parasitismo en ninfas y adultos de Neocurtilla claraziana, por dos especies de thelastomatidos, como parte de un estudio de campo sobre plagas agrícolas. Las ninfas y los adultos de este insecto fueron aisladas de pastizales de la Provincia de Buenos Aires, Argentina, utilizando soluciones tensio-activas. Las especies de nematodos Gryllophila skrjabini Sergiev, 1923 y Cephalobellus magalhaesi Schwenk, 1926 son descriptas brevemente y sus medidas son dadas. Ambos nematodos son citados por primera vez para Argentina, constituyendo Cephalobellus magalhaesi el segundo aislamiento de esta especie en el mundo. Neocurtilla clarziana constituyó un nuevo registro de hospedador para G. skrjabini.
Assuntos
Animais , Gryllidae/parasitologia , Oxyurida/classificação , Oxyurida/crescimento & desenvolvimento , Argentina , DemografiaRESUMO
Thelastomatidae is one of the largest families parasitizing insects, within the order Oxyurida. In this work we reported parasitism in nymphs and adults of Neocurtilla claraziana by two different thelastomatid species as a part of a field survey on agricultural pests. Nymphs and adults of this insect were isolated from grasslands of Buenos Aires State, Argentina using a tensio-active solution. The nematode species Gryllophila skrjabini Sergiev, 1923 and Cephalobellus magalhaesi Schwenk, 1926 are briefly described and measurements are given. Both nematodes are reported for the first time in Argentina with C. magalhaesi being the second isolation of this species in the world. Neocurtilla clarziana is a new host record for G. skrjabini.(AU)
Thelastomatidae es una de las principales familias que parasitan insectos, dentro del orden Oxyurida. En este trabajo informamos parasitismo en ninfas y adultos de Neocurtilla claraziana, por dos especies de thelastomatidos, como parte de un estudio de campo sobre plagas agrícolas. Las ninfas y los adultos de este insecto fueron aisladas de pastizales de la Provincia de Buenos Aires, Argentina, utilizando soluciones tensio-activas. Las especies de nematodos Gryllophila skrjabini Sergiev, 1923 y Cephalobellus magalhaesi Schwenk, 1926 son descriptas brevemente y sus medidas son dadas. Ambos nematodos son citados por primera vez para Argentina, constituyendo Cephalobellus magalhaesi el segundo aislamiento de esta especie en el mundo. Neocurtilla clarziana constituyó un nuevo registro de hospedador para G. skrjabini.(AU)