Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Parasite ; 31: 22, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38602374

RESUMEN

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.


Title: Parasites (Monogenea) des tilapias Oreochromis niloticus et Coptodon rendalli (Cichlidae) dans une source au Brésil. Abstract: Dans la présente étude, nous avons examiné 30 individus de cichlidés africains introduits, Oreochromis niloticus et Coptodon rendalli, collectés dans une source fluviale du fleuve Pardo, bassin du fleuve Paranapanema, dans le sud-est du Brésil. Sur la base d'analyses morphologiques et moléculaires du gène partiel de l'ADNr LSU, nous avons identifié quatre espèces de monogènes, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei et Scutogyrus longicornis sur les branchies d'O. niloticus, alors que les individus de C. rendalli étaient infestés uniquement par C. papernastrema. Il s'agit du premier signalement de C. mbirizei et C. papernastrema chez des tilapias du Brésil. Les conséquences écologiques de l'introduction d'espèces exotiques de tilapia telles que O. niloticus et C. rendalli ainsi que leurs monogènes parasites dans un environnement sauvage représenté par une source fluviale sont discutées. Nos nouvelles données moléculaires sur Cichlidogyrus et Scutogyrus contribuent à l'étude des interrelations phylogénétiques de ces genres de monogènes largement distribués puisque leur composition spécifique est encore incertaine.


Asunto(s)
Cíclidos , Enfermedades de los Peces , Parásitos , Tilapia , Trematodos , Humanos , Animales , Tilapia/parasitología , Cíclidos/parasitología , Ríos , Filogenia , Brasil/epidemiología , Branquias/parasitología , Enfermedades de los Peces/epidemiología , Enfermedades de los Peces/parasitología
2.
Parasitol Int ; 97: 102796, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37595832

RESUMEN

Myxozoans of Ceratomyxidae Doflein, 1899 are common coelozoic parasites of marine life, and are also found less frequently in freshwater fish. The present study describes Ceratomyxa ranunculiformis n. sp. as a new freshwater myxosporean species infecting the gall bladder of the Amazonian sciaenid Plagioscion squamosissimus. The new Ceratomyxa was described based on its host, myxospore morphology, ribosomal rDNA gene sequencing, parasite distribution, and phylogenetic analysis. Immature and mature plasmodia were tadpole-shaped or pyriform, and exhibited slow undulatory motility. The myxospores were elongated and crescent-shaped in the frontal view, with a sutural line between two valves, which had rounded ends. The measurements of the formalin-fixed myxospores were: average length 4.9 (4.0-6.6) µm, average thickness 37.6 (32.4-43.9) µm, average posterior angle 165° (154°-173°). Two ovoid polar capsules of equal size, average length 2.0 (1.4-3.0) µm and average width 1.9 (1.4-2.4) µm, were located adjacent to the suture and contained polar filaments with 2-3 coils. The integrated comparative analysis of the morphological characteristics and molecular analyses of the ribosomal rDNA genes supported the identification of a new species of coelozoic Ceratomyxa. Maximum likelihood analyses showed the new species clustering within a well-supported clade, together with all the other Amazonian freshwater ceratomyxids.


Asunto(s)
Myxozoa , Animales , Myxozoa/genética , Brasil , Filogenia , Peces , ADN Ribosómico/genética , Agua Dulce
3.
Mycologia ; 115(3): 427-436, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37159342

RESUMEN

This contribution is part of a series devoted to the phylogeny and taxonomy of powdery mildews, with an emphasis on North American taxa. An overview of Cystotheca species is given, including references to ex-type sequences or, if unavailable, proposals for representative reference sequences for phylogenetic-taxonomic purposes. The new species C. mexicana is described, based on Mexican collections on Quercus glaucoides × Quercus microphylla and Quercus liebmannii × Q. microphylla. Cystotheca lanestris is reported for the first time worldwide on Quercus laceyi (Collected in Mexico) and on Q. toumeyi (collected in Arizona, USA). Cystotheca lanestris on Q. agrifolia and on Q. cerris is reported for the first time in Mexico. Epitypes with ex-epitype sequences are designated for Cystotheca wrightii, Lanomyces tjibodensis (= C. tjibodensis), Sphaerotheca kusanoi, and S. lanestris (C. lanestris).


Asunto(s)
Quercus , Filogenia , México , Arizona
4.
J Phycol ; 59(4): 725-737, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37232027

RESUMEN

Coolia species are epiphytic and benthic dinoflagellates with a cosmopolitan distribution in tropical and subtropical areas. In the austral summer of 2016, during a survey in Bahía Calderilla, a dinoflagellate of the genus Coolia was detected in macroalgae samples, and a clonal culture was established. Subsequently, the cultured cells were observed by scanning electron microscopy (SEM) and identified as C. malayensis based on their morphological characteristics. Phylogenetic analyses based on the LSU rDNA D1/D2 regions confirmed that strain D005-1 corresponded to C. malayensis and clustered with strains isolated from New Zealand, Mexico, and Asia Pacific countries. Although the strain D005-1 culture did not contain yessotoxin (YTX), cooliatoxin, 44-methyl gambierone, or its analogs in detectable amounts by LC-MS/MS, more research is needed to evaluate its toxicity and to determine the possible impact of C. malayensis in northern Chilean waters.


Asunto(s)
Dinoflagelados , Monitoreo del Ambiente , Dinoflagelados/clasificación , Océano Pacífico , Espectrometría de Masas en Tándem , Algas Marinas , Microscopía Electrónica de Rastreo
5.
J Fungi (Basel) ; 8(10)2022 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36294603

RESUMEN

During a survey of Mucorales from a forest located in Pernambuco state, Brazil, two new Backusella species were discovered and described based on morphological and molecular data (internal transcribed spacer and large subunit ribosomal DNA sequences). Both species were characterized as unbranched sporangiophores and sporangia with columellae of varied shapes forming. Multispored sporangiola were frequent, whereas unispored sporangiola were rare. URM 8395 forms sporangiophores that may support hyaline, slightly curved or circinate pedicels with multispored sporangiola at their apical portion, and abundant giant cells and chlamydospores. Columellae of sporangia are hyaline, conical (majority), or ellipsoidal with a truncate base, globose to subglobose or subglobose to conical, and, rarely, with slight medial constriction. URM 8427 does not form sporangiola from pedicels, giant cells are not observed, and columellae of sporangia are globose to subglobose, cylindrical with a truncate base, some with a slight constriction, applanate, obovoid, ellipsoidal, or, rarely, conical. Some columellae may have one side more swollen than the other and some are arranged obliquely on the sporangiophores. Sterile sporangia may or may not be formed on short sporophores. The detailed description and illustration of both novel species as well as an identification key for Backusella from the Americas are provided.

6.
J Nematol ; 54(1): 20220057, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36742266

RESUMEN

Pratylenchus is one of the most limiting nematodes of Musaceae production in the world. Knowledge of the nematode species is one of the requirements for its management in the field. This study aimed to identify up to the species level Pratylenchus populations associated with plantain and banana crops in the states of Caldas, Quindío, and Valle del Cauca in Colombia. In these regions, Pratylenchus has been reported to affect these crops in the past, but with records of the nematode only up to the genus level. For this purpose, five populations of Pratylenchus extracted from samples composed of roots and rhizospheric soil, four from plantain and one from banana, were identified through morphological, morphometric, and molecular analysis (sequencing of the D2-D3 of rRNA and cytochrome oxidase subunit I of mtDNA). All populations were identified as P. araucensis, a species reported previously in eastern Colombia, and one that the present study found in the center and southwest of the country, indicating that this species of nematode is widely distributed in the Musaceae-producing areas of Colombia. The present study reports the first COI mtDNA sequences for this species of nematode.

7.
Zootaxa ; 4619(2): zootaxa.4619.2.13, 2019 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-31716312

RESUMEN

The females of Xyo pseudohystrix Travassos Kloss, 1958 (Nematoda: Oxyuridomorpha: Hystrignathidae) are redescribed and illustrated with the aid of SEM. New features of the cephalic end, arrangement of the cervical spines and genital tract were observed. The taxonomic status of the species is discussed on the basis of discrepancies with the generic diagnosis of Xyo Cobb, 1898. Due to the lack of proper information on the genus the status of incertae sedis is proposed. The identity of the males was confirmed by molecular studies and the morphology of the specimens previously assigned by Christie (1932) as males of Hystrignathus rigidus Leidy, 1858 correspond to the current species. New locality records are given for the states of Georgia and Ohio, USA. The phylogenetic position of the species is inferred on the basis of the D2-D3 segment of the LSU rDNA and SSU rDNA.


Asunto(s)
Escarabajos , Nematodos , Animales , ADN Ribosómico , Femenino , Georgia , Masculino , Ohio , Filogenia
8.
J Helminthol ; 94: e61, 2019 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-31328706

RESUMEN

A new species of the genus Plagiorhynchus Lühe, 1911 from the intestine of the long-billed curlew (Numenius americanus) from northern Mexico is described. Plagiorhynchus (Plagiorhynchus) aznari n. sp. is morphologically distinguished from other congeneric species from the Americas by having a trunk expanded anteriorly and a cylindrical proboscis, armed with 19 longitudinal rows of hooks, with 14-15 hooks each row. Nearly complete sequences of the small subunit and large subunit of the nuclear ribosomal DNA of the new species were determined and compared with available sequences from GenBank. Phylogenetic analyses inferred from the two molecular markers consistently showed that P. (Plagiorhynchus) aznari n. sp. is closely related to P. (Plagiorhynchus) allisonae, and this clade is sister to a clade formed by P. (Prosthorhynchus) transversus and P. (Prosthorhynchus) cylindraceus from Plagiorhynchidae. The new species represents the second record of the genus in Mexico and the fourth species in the Americas. The phylogenetic relationships among the members of the order Polymorphida in this study provide significant insights into the evolution of ecological associations between parasites and their definitive hosts. Our analyses suggest that the colonization of marine mammals, fish-eating birds and waterfowl in Polymorphidae might have occurred independently, from a common ancestor of Centrorhynchidae and Plagiorhynchidae that colonized terrestrial birds and mammals.


Asunto(s)
Acantocéfalos/anatomía & histología , Acantocéfalos/clasificación , Aves/parasitología , Helmintiasis Animal/parasitología , Filogenia , Acantocéfalos/aislamiento & purificación , Animales , ADN de Helmintos/genética , ADN Ribosómico/genética , Femenino , Intestinos/parasitología , Masculino , México
9.
Zootaxa ; 4551(2): 221-230, 2019 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-30790824

RESUMEN

Lepidonema magnum Morffe García, 2010 (Nematoda: Oxyuridomorpha: Hystrignathidae) is redescribed and illustrated with the aid of SEM. New features of the cephalic end and genital tract of the females were observed. New locality records are given. The phylogenetic position of the species is inferred on the basis of the D2-D3 segment of the 28S LSU rDNA and 18S SSU rDNA. L. magnum forms a monophyletic clade formed by other hystrignathids: Coynema poeyi (Coy, García Álvarez, 1993), two species of Longior Travassos Kloss, 1958 and two Hystrignathus Leidy, 1850.


Asunto(s)
Escarabajos , Nematodos , Animales , Cuba , ADN Ribosómico , Femenino , Filogenia
10.
Zootaxa ; 4497(1): 29-40, 2018 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-30313663

RESUMEN

Coynema poeyi (Coy, García Álvarez, 1993) (Oxyuridomorpha: Hystrignathidae) is redescribed and illustrated with the aid of SEM. New features of the cephalic end of both sexes and copulatory papillae pattern of the males were observed and the generic diagnosis is emended in order to include such features. New locality records are given. The phylogenetic position of the species is inferred on the basis of the D2-D3 segment of the LSU rDNA. C. poeyi is located basal in a monophyletic clade formed by other hystrignathids: two species of Longior Travassos Kloss, 1958 and Hystrignathus sp.


Asunto(s)
Escarabajos , Filogenia , Animales , Cuba , Femenino , Masculino , Oxyurida
11.
J Environ Sci (China) ; 67: 330-343, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29778166

RESUMEN

Arbuscular mycorrhizal fungi (AMF) are important during revegetation of mining sites, but few studies compared AMF community in revegetated sites with pristine adjacent ecosystems. The aim of this study was to assess AMF species richness in a revegetated iron-mining site and adjacent ecosystems and to relate AMF occurrence to soil chemical parameters. Soil samples were collected in dry and rainy seasons in a revegetated iron-mining site (RA) and compared with pristine ecosystems of forest (FL), canga (NG), and Cerrado (CE). AMF species were identified by spore morphology from field and trap cultures and by LSU rDNA sequencing using Illumina. A total of 62 AMF species were recovered, pertaining to 18 genera and nine families of Glomeromycota. The largest number of species and families were detected in RA, and Acaulospora mellea and Glomus sp1 were the most frequent species. Species belonging to Glomeraceae and Acaulosporaceae accounted for 42%-48% of total species richness. Total number of spores and mycorrhizal inoculum potential tended to be higher in the dry than in the rainy season, except in RA. Sequences of uncultured Glomerales were dominant in all sites and seasons and five species were detected exclusively by DNA-based identification. Redundancy analysis evidenced soil pH, organic matter, aluminum, and iron as main factors influencing AMF presence. In conclusion, revegetation of the iron-mining site seems to be effective in maintaining a diverse AMF community and different approaches are complementary to reveal AMF species, despite the larger number of species being identified by traditional identification of field spores.


Asunto(s)
Ecosistema , Restauración y Remediación Ambiental , Micorrizas/fisiología , Microbiología del Suelo , Biodiversidad , Bosques , Hierro , Minería , Raíces de Plantas/microbiología , Esporas Fúngicas
12.
Harmful Algae ; 70: 73-89, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29169570

RESUMEN

A new species of toxic benthic dinoflagellate is described based on laboratory cultures isolated from two locations from Brazil, Rio de Janeiro and Bahia. The morphology was studied with SEM and LM. Cells are elliptical in right thecal view and flat. They are 37-44µm long and 29-36µm wide. The right thecal plate has a V shaped indentation where six platelets can be identified. The thecal surface of both thecal plates is smooth and has round or kidney shaped and uniformly distributed pores except in the central area of the cell, and a line of marginal pores. Some cells present an elongated depression on the central area of the apical part of the right thecal plate. Prorocentrum caipirignum is similar to Prorocentrum lima in its morphology, but can be differentiated by the general cell shape, being elliptical while P. lima is ovoid. In the phylogenetic trees based on ITS and LSU rDNA sequences, the P. caipirignum clade appears close to the clades of P. lima and Prorocentrum hoffmannianum. The Brazilian strains of P. caipirignum formed a clade with strains from Cuba, Hainan Island and Malaysia and it is therefore likely that this new species has a broad tropical distribution. Prorocentrum caipirignum is a toxic species that produces okadaic acid and the fast acting toxin prorocentrolide.


Asunto(s)
Dinoflagelados/crecimiento & desarrollo , Dinoflagelados/aislamiento & purificación , Filogenia , Brasil , Diferenciación Celular , ADN Protozoario/genética , ADN Ribosómico/genética , Dinoflagelados/clasificación , Dinoflagelados/genética , Ácido Ocadaico/metabolismo , Ácido Ocadaico/toxicidad
13.
Harmful Algae ; 66: 20-28, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28602250

RESUMEN

The Gambierdiscus genus is a group of benthic dinoflagellates commonly associated with ciguatera fish poisoning (CFP), which is generally found in tropical or sub-tropical regions around the world. Morphologically similar species within the genus can vary in toxicity; however, species identifications are difficult or sometimes impossible using light microscopy. DNA sequencing of ribosomal RNA genes (rDNA) is thus often used to identify and describe Gambierdiscus species and ribotypes, but the expense and time can be prohibitive for routine culture screening and/or large-scale monitoring programs. This study describes a restriction fragment length polymorphism (RFLP) typing method based on analysis of the large subunit rDNA that can successfully identify at least nine of the described Gambierdiscus species and two Fukuyoa species. The software programs DNAMAN 6.0 and Restriction Enzyme Picker were used to identify a set of restriction enzymes (SpeI, HpyCH4IV, and TaqαI) capable of distinguishing most of the known Gambierdiscus species for which DNA sequences were available. This assay was tested using in silico analysis and cultured isolates, and species identifications of isolates assigned by RFLP typing were confirmed by DNA sequencing. To verify the assay and assess intra-specific heterogeneity in RFLP patterns, identifications of 63 Gambierdiscus isolates comprising ten Gambierdiscus species, one ribotype, and two Fukuyoa species were confirmed using RFLP typing, and this method was subsequently employed in the routine identification of isolates collected from the Caribbean Sea. The RFLP assay presented here reduces the time and cost associated with morphological identification via scanning electron microscopy and/or DNA sequencing, and provides a phylogenetically sensitive method for routine Gambierdiscus species assignment.


Asunto(s)
ADN de Algas/análisis , ADN Protozoario/análisis , ADN Ribosómico/análisis , Dinoflagelados/clasificación , Polimorfismo de Longitud del Fragmento de Restricción , Bahamas , Región del Caribe , Dinoflagelados/genética , Florida , Islas Virgenes de los Estados Unidos
14.
Harmful Algae ; 55: 56-65, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-28073547

RESUMEN

Azadinium poporum produces a variety of azaspiracids and consists of several ribotypes, but information on its biogeography is limited. A strain of A. poporum (GM29) was incubated from a Gulf of Mexico sediment sample. Strain GM29 was characterized by a plate pattern of po, cp, x, 4', 3a, 6″, 6C, 5S, 6‴, 2⁗, a distinct ventral pore at the junction of po and the first two apical plates, and a lack of an antapical spine, thus fitting the original description of A. poporum. The genus Azadinium has not been reported in waters of the United States of America before this study. Molecular phylogeny, based on large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences, reveals that strain GM29 is nested within the well-resolved A. poporum complex, but forms a sister clade either to ribotype B (ITS) or ribotype C (LSU). It is, therefore, designated as a new ribotype, termed as ribotype D. LSU and ITS sequences similarity among different ribotypes of A. poporum ranges from 95.4% to 98.2%, and from 97.1% to 99.2% respectively, suggesting that the LSU fragment is a better candidate for molecular discrimination. Azaspiracid profiles were analyzed using LC-MS/MS and demonstrate that strain GM29 produces predominantly AZA-2 with an amount of 45fg/cell. The results suggest that A. poporum has a wide distribution and highlights the risk potential of azaspiracid intoxication in the United States.


Asunto(s)
Dinoflagelados , Toxinas Marinas/química , Filogenia , Compuestos de Espiro/química , ADN Ribosómico/genética , ADN Espaciador Ribosómico/genética , Dinoflagelados/química , Dinoflagelados/clasificación , Dinoflagelados/citología , Dinoflagelados/genética , Golfo de México , Análisis de Secuencia de ADN
15.
J Phycol ; 51(5): 990-9, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26986893

RESUMEN

In the present study, we redescribed Gyrodinium resplendens through incubation of process bearing cysts extracted from sediment collected in the northern Gulf of Mexico. The morphology and ultrastructure of the motile stage and cyst stage were examined using light microscopy, scanning electron microscopy, and transmission electron microscopy and this revealed that the species should be transferred to the genus Barrufeta. This genus differs from other gymnodinioid genera in possessing a Smurf-cap apical structure complex (ASC) and currently encompasses only one species, Barrufeta bravensis. B. resplendens shows a Smurf-cap ASC that consists of three rows of elongated vesicles with small knobs in the middle one. B. resplendens is very similar to B. bravensis in cell morphology, but can be separated using the ultrastructure such as the shape and location of nucleus and pyrenoids, which highlights the importance of ultrastructure at inter-specific level in the genus Barrufeta. The unique cysts of B. resplendens are brown and process bearing, and have a tremic archeopyle with a zigzag margin on the dorsal side of the epicyst, and not polar as in cysts of Polykrikos. The cysts do not survive the palynological treatment used here and probably have a wide distribution. Maximum-likelihood and Bayesian inference were carried out based on partial large subunit ribosomal DNA (LSU rDNA) sequences. Molecular phylogeny supports that the genus Barrufeta is monophyletic, and that the genus Gymnodinium is polyphyletic. Our results suggest that details of the ASC together with ultrastructure are potential features to subdivide the genus Gymnodinium.

16.
Mycologia ; 106(2): 323-7, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24782499

RESUMEN

A combined dataset of rDNA ITS and LSU sequences was used to infer the phylogenetic relationships of Hydnochaete peroxydata (≡ Hydnum peroxydatum), the type species of Hydnochaete. The species was retrieved nested within the Hymenochaete s. str. clade; therefore Hydnochaete is regarded as a synonym of Hymenochaete and the new combination Hymenochaete peroxydata is proposed.


Asunto(s)
Basidiomycota/clasificación , Basidiomycota/aislamiento & purificación , Filogenia , Basidiomycota/genética , ADN de Hongos/genética , ADN Ribosómico/genética , Datos de Secuencia Molecular
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA