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Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae)
Be?ak, Maria Luiza;Be?ak, Willy;Pereira, Alexandre;
Anais da Academia Brasileira de Ciências , 2003, DOI: 10.1590/S0001-37652003000300004
Abstract: the positioning of macrochromosomes of bothrops jararaca and bothrops insularis (viperidae) was studied in undistorted radial metaphases of uncultured cells (spermatogonia and oogonia) not subjected to spindle inhibitors. colchicinized metaphases from uncultured (spleen and intestine) and cultured tissues (blood) were also analyzed. we report two antagonic non-random chromosome arrangements in untreated premeiotic cells: the parallel configuration with homologue chromosomes associated side by side in the metaphase plate and the antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphase ring. the antiparallel aspect also appeared in colchicinized cells. the spatial chromosome arrangement in both configurations is groupal size-dependent and maintained through meiosis. we also describe, in untreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. in b. jararaca males we observed that some gonad regions present changes in the meiotic mechanism. in this case, endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicated second metaphases of meiosis with the suppression of first meiosis. by a successive division, these cells form nuclei with one set of chromosomes. chromosome doubling in oogonia is known in hybrid species and in parthenogenetic salamanders and lizards. this species also presented chromosome rearrangements leading to aneuploidies in mitosis and meiosis. it is suggested that somatic pairing, endomitosis, meiotic alterations, and chromosomal aberrations can be correlated processes. similar aspects of nuclei configurations, endomitosis and reductional mitosis were found in other viperidae and colubridae species.
Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae)  [cached]
Be?ak Maria Luiza,Be?ak Willy,Pereira Alexandre
Anais da Academia Brasileira de Ciências , 2003,
Abstract: The positioning of macrochromosomes of Bothrops jararaca and Bothrops insularis (Viperidae) was studied in undistorted radial metaphases of uncultured cells (spermatogonia and oogonia) not subjected to spindle inhibitors. Colchicinized metaphases from uncultured (spleen and intestine) and cultured tissues (blood) were also analyzed. We report two antagonic non-random chromosome arrangements in untreated premeiotic cells: the parallel configuration with homologue chromosomes associated side by side in the metaphase plate and the antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphase ring. The antiparallel aspect also appeared in colchicinized cells. The spatial chromosome arrangement in both configurations is groupal size-dependent and maintained through meiosis. We also describe, in untreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. In B. jararaca males we observed that some gonad regions present changes in the meiotic mechanism. In this case, endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicated second metaphases of meiosis with the suppression of first meiosis. By a successive division, these cells form nuclei with one set of chromosomes. Chromosome doubling in oogonia is known in hybrid species and in parthenogenetic salamanders and lizards. This species also presented chromosome rearrangements leading to aneuploidies in mitosis and meiosis. It is suggested that somatic pairing, endomitosis, meiotic alterations, and chromosomal aberrations can be correlated processes. Similar aspects of nuclei configurations, endomitosis and reductional mitosis were found in other Viperidae and Colubridae species.
Body size, reproductive biology and abundance of the rare pseudoboini snakes genera Clelia and Boiruna (Serpentes, Colubridae) in Brazil
Lígia Pizzatto
Phyllomedusa : Journal of Herpetology , 2005,
Abstract: Pseudoboini snakes of the genera Clelia and Boiruna are apparently rare in nature and certainly rare in collections. This work presents data on body size, reproduction and abundance of five Brazilian species of these genera, in the largest collection of snakes in Latin America, the Instituto Butantan. Despite scarcity of data, follicular cycle seems to be continuous in most species, except Clelia rustica, which occurs in highlands. Females are largerthan males in all species, and fecundity is low when compared to other pseudoboini. Abundance is very low for all species even considering 100 years of collecting, and it is decreasing in recent decades when compared to other snakes (Bothrops jararaca, Oxyrhopus guibei, O. clathratus, Philodryas patagoniensis, Sibynomorphus mikanii, and Spilotes pullatus). The studied species present at least five traits of commonly threatened species and require more attention in researches and conservation policies.
New localities and altitudinal records for the snakes Oxyrhopus petolarius, Spilotes pullatus, and Urotheca fulviceps in Talamanca, Costa Rica
González-Maya, José F.;Cardenal-Porras, Josue;Wyatt, Sarah A.;Mata-Lorenzen, Juan;
Revista mexicana de biodiversidad , 2011,
Abstract: distribution records are the basis for conservation planning and species conservation assessments. new locality and elevation records are reported for 2 dipsadid snakes (oxyrhopus petolarius and urotheca fulviceps) and 1 colubrid (spilotes pullatus) from the talamanca mountain range of costa rica as established by direct sightings. these new records represent important additions to the knowledge of the species and more generally for the talamanca ecoregion.
Oral microbiota of Brazilian captive snakes
Fonseca, MG;Moreira, WMQ;Cunha, KC;Ribeiro, ACMG;Almeida, MTG;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2009, DOI: 10.1590/S1678-91992009000100006
Abstract: the present work aimed to determine the oral microbiotic composition of snakes from s?o josé do rio preto city, s?o paulo state, brazil. ten snake species, comprising the families boidae, colubridae, elapidae and viperidae, were submitted to microbiological examination of their oral cavity, which indicated positivity for all buccal samples. gram-negative bacilli, gram-negative cocci bacilli, gram-positive bacilli and gram-positive cocci were isolated from the snakes. among isolated bacterium species, the occurrence of coagulase-negative staphylococci in the buccal cavity of crotalus durissus (viperiade), eunectes murinus (boidae), mastigodryas bifossatus (colubridae) and bacillus subtilis, common to oral cavity of bothrops alternatus (viperidae) and phalotris mertensi (colubridae), was detected. it was observed higher diversity of isolated bacteria from the oral cavity of micrurus frontalis (elapidae) and philodryas nattereri (colubridae), as well as the prevalence of gram-positive baccillus and gram-positive cocci. the composition of the oral microbiota of the studied snakes, with or without inoculating fangs, is diverse and also related to the formation of abscesses at the bite site in the victims of the ophidian accidents, and to pathogenic processes in the snakes that host these microorganisms.
New reports on parasitism by Haplometroides buccicola (Digenea, Plagiorchiidae) in Brazilian snakes
Santos, KR;Barrella, TH;Zica, EOP;Silva, RJ;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2008, DOI: 10.1590/S1678-91992008000300011
Abstract: the occurrence of haplometroides buccicola (digenea, plagiorchiidae) in the esophagus of two brazilian snakes is reported in the present study. the trematodes were collected from one micrurus corallinus (elapidae) and one phalotris lativittatus (colubridae); both snakes were found in botucatu city, s?o paulo state, brazil. morphological and morphometric analyses of the trematodes are presented. for the first time micrurus corallinus has been recorded as a host for h. buccicola and this is the second time that p. lativittatus has been reported as a host for this trematode species.
Report on the occurrence of Haplometroides buccicola (Trematoda, Digenea, Plagiorchiidae) infecting Phalotris lativittatus (Serpentes, Colubridae) in Brazil
Silva, R. J.;Andrade, P. A.;Monteiro e Silva, H. A.;Rossellini, M.;Barrella, T. H.;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2005, DOI: 10.1590/S1678-91992005000300013
Abstract: haplometroides buccicola (trematoda, digenea, plagiorchiidae) was reported in the mouth and oesophagus of phalotris lativittatus (serpentes, colubridae) from botucatu, s?o paulo state, brazil. this is the first report on the occurrence of h. buccicola parasitizing p. lativittatus. the haplometroides genus was also discussed and the most important morphological characters for the identification of the species h. buccicola and h. odhneri are presented.
Evolution of the mitochondrial genome in snakes: Gene rearrangements and phylogenetic relationships
Jie Yan, Hongdan Li, Kaiya Zhou
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-569
Abstract: The mitochondrial genomes were sequenced for four taxa representing four different families, and each had a different gene arrangement. Comparative analyses with other snake mitochondrial genomes allowed us to summarize six types of mitochondrial gene arrangement in snakes. Phylogenetic reconstruction with commonly used methods of phylogenetic inference (BI, ML, MP, NJ) arrived at a similar topology, which was used to reconstruct the evolution of mitochondrial gene arrangements in snakes.The phylogenetic relationships among the major families of snakes are in accordance with the mitochondrial genomes in terms of gene arrangements. The gene arrangement in Ramphotyphlops braminus mtDNA is inferred to be ancestral for snakes. After the divergence of the early Ramphotyphlops lineage, three types of rearrangements occurred. These changes involve translocations within the IQM tRNA gene cluster and the duplication of the CR. All phylogenetic methods support the placement of Enhydris plumbea outside of the (Colubridae + Elapidae) cluster, providing mitochondrial genomic evidence for the familial rank of Homalopsidae.Snakes are a large group of reptiles with a broad range of morphological features, of which many are evolutionarily selected by their habitats. Snakes have conventionally been divided into two groups. The fossorial scolecophidians (blindsnakes and threadsnakes) are small snakes with a small gape size that feed on small prey on a frequent basis. The second major group, the alethinophidians (or "true snakes") are more ecologically diverse and most species feed on relatively large prey on an infrequent basis. True snakes are further split into the Henophidia and the Caenophidia. The caenophidians, which are also called advanced snakes, include the aquatic genus Acrochordus and the Colubroidea. The Colubroidea is subdivided into the families Atractaspididae, Elapidae, Viperidae, and Colubridae. A small colubrid subfamily, Homalopsinae, was first attributed familial
New record of Haplometroides intercaecalis (Digenea, Plagiorchiidae) infecting a Brazilian snake
Silva, R. J.;Béda, A. F.;Ferreira, V. L.;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2008, DOI: 10.1590/S1678-91992008000100013
Abstract: phalotris matogrossensis (serpentes, colubridae) was reported as a new host for haplometroides intercaecalis (digenea, plagiorchiidae). the host snake was obtained from the municipality of anastácio, state of mato grosso do sul, brazil. one specimen of h. intercaecalis was recovered from the esophagus of the host and identified by the intercecal position of the vitellaria in the pre-acetabular region. this paper describes the second report of the occurrence of this trematode in fossorial snakes of the genus phalotris in the state of mato grosso do sul, brazil.
New localities and altitudinal records for the snakes Oxyrhopus petolarius, Spilotes pullatus, and Urotheca fulviceps in Talamanca, Costa Rica Nuevas localidades y registros de elevación de las serpientes Oxyrhopus petolarius, Spilotes pullatus y Urotheca fulviceps en Talamanca, Costa Rica  [cached]
José F. González-Maya,Josue Cardenal-Porras,Sarah A. Wyatt,Juan Mata-Lorenzen
Revista mexicana de biodiversidad , 2011,
Abstract: Distribution records are the basis for conservation planning and species conservation assessments. New locality and elevation records are reported for 2 dipsadid snakes (Oxyrhopus petolarius and Urotheca fulviceps) and 1 colubrid (Spilotes pullatus) from the Talamanca mountain range of Costa Rica as established by direct sightings. These new records represent important additions to the knowledge of the species and more generally for the Talamanca ecoregion. Los registros de distribución de especies son la base para la planificación y evaluación del estado de conservación de éstas y los ecosistemas en que habitan. Se presentan 3 nuevas localidades y registros de elevación de 2 especies de dipsádidos (Oxyrhopus petolarius y Urotheca fulviceps) y 1 especie de colúbrido (Spilotes pullatus) en la cordillera de Talamanca, con base en observaciones directas. Estos registros representan importantes adiciones tanto para la ecoregión de Talamanca, como para el aumento significativo en el conocimiento de estas especies.
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