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Cleusa Yoshiko Nagamachi - One of the best experts on this subject based on the ideXlab platform.
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Gymnotus coatesi gymnotiformes a case of colocation of multiple sites of 18s rdna with telomeric sequences
Zebrafish, 2017Co-Authors: Milla De Andrade Machado, Julio Cesar Pieczarka, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomempaixao, Cleusa Yoshiko NagamachiAbstract:Abstract Gymnotus coatesi is a small and rare species of banded knife fish that was originally described by LaMonte in 1935, found along the main stretch of the Amazon River. There is no described ...
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pintura cromossomica em Gymnotus arapaima com sonda e cromossomo total de Gymnotus carapo gymnotiformes gymnotidae
Semina-ciencias Agrarias, 2017Co-Authors: Milla De Andrade Machado, Julio Cesar Pieczarka, Fernando Henrique Ramos Silva, P C M Obrien, Malcolm Andrew Ferguson Smith, Cleusa Yoshiko NagamachiAbstract:O genero Gymnotus e um dos generos mais especiosos (40 especies) e mais amplamente distribuidos nas aguas continentais da America do Sul, com maior ocorrencia na bacia amazonica, onde varias especies ocorrem em simpatria. A citogenetica tem sido uma importante ferramenta na citotaxinomia e na elucidacao dos processos evolutivos no genero, que possui uma diversidade cariotipica elevada, sendo os cariotipos especie-especificos, mesmo nas especies que possuem o mesmo numero diploide e sao um fator de isolamento reprodutivo pre-zigotico nas especies em simpatria. Cromossomos metafasicos de Gymnotus arapaima (GAR, 2n=44, FC: 24 m/sm + 20 st/a) foram hibridizados com sondas de cromossomo total de Gymnotus carapo (GCA, 2n=42). A sonda da regiao 1 (GCA 20) hibridizou um unico cromossomo, o GAR 19, portador da NOR. As sondas da regiao 2 (GCA 1, 2, 3 e 16) hibridizaram os cromossomos de GAR: 1, 2, 14 e 18 e 21, o braco curto do par 4 e braco curto e uma parte do braco longo do par 13. As da regiao 3 (GCA 4, 5, 6, 7, 8, 17, 18, 19) hibridizaram os cromossomos de GAR 3, 5, 6, 5, 16, 20 e 22, o braco longo do par 4 e parte do braco longo do par 13. As da regiao 4 (GCA 9 – 15 e 21) hibridizaram os cromossomo 7-12 e 17. Ate a presente analise pelo menos 3 pares (GAR 1, 16 e 20) se encontram conservados em relacao ao cariotipo de GCA, enquanto outros encontram-se fragmentados e/ou fusionados. A pintura cromossomica em Gymnotus e uma ferramenta recente que, como observado no cariotipo analisado e em trabalhos anteriores, vem mostrando que os rearranjos cromossomicos no genero sao numerosos e o processo evolutivo dinâmico.
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Chromosome painting reveals multiple rearrangements between Gymnotus capanema and Gymnotus carapo (Gymnotidae, Gymnotiformes).
Cytogenetic and genome research, 2013Co-Authors: Cleusa Yoshiko Nagamachi, Susana Suely Rodrigues Milhomem, Julio Cesar Pieczarka, Jéssica Almeida Batista, Patricia Caroline Mary O’brien, M. A. Ferguson-smithAbstract:The genus Gymnotus (Gymnotiformes) is a group of fishes with karyotypic plasticity, demonstrated by cytogenetic studies using whole chromosome probes of G. carapo (GCA, 2n = 42) that were obtained by flow-sorting from fibroblast cultures. In the present work we undertook comparative mapping of the karyotype of G. capanema (GCP, 2n = 34) with GCA, 2n = 42 painting probes. The results demonstrate that the karyotype of G. capanema is extensively rearranged when compared to G. carapo. From the 12 chromosome pairs of G. carapo that can be individually differentiated (GCA1-3, 6, 7, 9, 14, 16 and 18-21), only 4 pairs (GCA6, 7, 19, and 20) maintained conserved synteny in G. capanema. From these 4, GCA6 and GCA20 correspond to individual chromosomes (GCP8 and GCP15), while the other 2 share homology with parts of GCP1 and GCP2, respectively. The remaining GCP chromosomes showed more complex hybridization patterns with homologies to other GCA pairs. These results demonstrate that the level of reorganization in the genome of G. capanema is much greater than in GCA, 2n = 42 and in karyomorph GCA, 2n = 40 which was previously analyzed by chromosome painting.
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Profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (Gymnotiformes) from the Eastern Amazon
Genetics and molecular biology, 2013Co-Authors: Karina Motta Melo, Julio Cesar Pieczarka, Cleusa Yoshiko Nagamachi, Ingrid Reale Alves, José Augusto De Oliveira David, Cesar Koppe GrisoliaAbstract:The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities.
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Are NORs always located on homeologous chromosomes? A FISH investigation with rDNA and whole chromosome probes in Gymnotus fishes (Gymnotiformes).
PloS one, 2013Co-Authors: Susana Suely Rodrigues Milhomem, Fausto Foresti, Julio Cesar Pieczarka, Priscilla Cardim Scacchetti, Patricia C. M. O’brien, Malcolm A. Ferguson-smith, Jose ́ C. Pansonato-alves, Cleusa Yoshiko NagamachiAbstract:Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs are derived. The separation of groups of species in the genus Gymnotus proposed by phylogenies with morphologic and molecular data is supported by our cytogenetic data.
James S Albert - One of the best experts on this subject based on the ideXlab platform.
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two new species of Gymnotus gymnotiformes gymnotidae from brazil and historical biogeography of the subgenus lamontianus
Copeia, 2020Co-Authors: Lesley Y Kim, William G. R. Crampton, James S AlbertAbstract:Gymnotus is the most species-rich and geographically widespread genus of gymnotiform electric fishes and has been widely explored to understand mechanisms of diversification in Neotropical freshwater fishes at a continental scale. Within Gymnotus, the subgenus Lamontianus is a phenotypically distinctive clade with an elongate, cylindrical body shape currently known from four valid species (G. anguillaris, G. cataniapo, G. pedanopterus, and G. tiquie) restricted to rivers draining the Guiana Shield. Here we use aspects of body-surface coloration, meristic, morphological, and osteological data, including cranial, laterosensory pore, and postcranial characters, to diagnose two new species of Lamontianus that inhabit the Aripuana and Arapiuns rivers that drain the Brazilian Shield. We also use geometric morphometric analyses of head shape to separate the new species from one another and other species of Lamontianus. We report biogeographic distributions for all species of Lamontianus and estimate ancestral geographic ranges and range evolution using the parametric biogeographic program BioGeoBEARS. We use the phylogeny of Lamontianus to test alternative hypotheses regarding lineage divergence times, before or after the formation of the modern East-draining Amazon at c. 10 Ma. Our analysis suggests that diversification in Lamontianus occurred primarily by geographic range fragmentation (vicariance) from an ancestral species distributed across the Western Guiana Shield. These results are similar to those of other Gymnotus and gymnotiform clades, where allopatric speciation and secondary contact due to geographic range expansion are commonly observed. This study brings to 46 the number of valid species of the genus Gymnotus, and to six the number of valid species of the subgenus Lamontianus.
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sexual size dimorphism in the macana tigrina Gymnotus javari gymnotidae gymnotiformes
Copeia, 2019Co-Authors: Aaron H Fronk, William G. R. Crampton, Jack M Craig, Lesley Y Kim, James S AlbertAbstract:Gymnotiform electric fishes exhibit many forms of sexual dimorphism, including sexual size dimorphism (SSD), aspects of head, jaw, and electric organ morphology, and electric signal waveform. However, sexual dimorphism is poorly documented in banded electric fishes (Gymnotus), where most species are monomorphic in external appearance and electric signal waveforms. Gathering comparative data on species of Gymnotus has historically been hampered by their predatory and territorial lifestyles, in that they are usually dispersed in their preferred habitats and often collected individually. Here data are presented from a population of G. javari from the Peruvian Amazon, examined for SSD (n = 55) and electric organ discharge (EOD) amplitude (n = 162). These results are compared with a syntopic population of G. carapo (n = 61), and also with G. omarorum (n = 24) from a population in Uruguay. Unlike most congeners, G. javari exhibits pronounced sexual dimorphism in total length and body weight, and EOD pulse amplitude is correlated with total length. A review of several ecological hypotheses on body-size distributions of each sex as a balance of multiple competing selection pressures finds none of these hypotheses adequately explain SSD in G. javari. Examining SSD in biogeographic and phylogenetic contexts leads to the conclusion that selection across different environments (e.g., local habitats, geographic regions) and through evolutionary time may have contributed to the evolution of SSD in some but not all lineages of Gymnotus.
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Molecular assessment of Gymnotus spp. (Gymnotiformes: Gymnotidae) fishing used as live baitfish in the Tietê River, Brazil
Neotropical Ichthyology, 2019Co-Authors: Lilian Paula Faria-pereira, James S Albert, Alexandre Wagner Silva Hilsdorf, Maria José Tavares Ranzani Paiva, Marcia Santos Nunes GalvaoAbstract:ABSTRACT The capture of live bait for sport fishing is an important activity for fishing communities. The main species used for this purpose are members of the genus Gymnotus, which comprises numerous species of cryptic nature that are difficult to identify based on external morphology. The aims of this work were to identify through partial sequences of the COI gene Gymnotus species fished in the Jacaré-Guaçu River, SP, and to develop a molecular diagnostic approach using PCR-RFLP to identify these species. Partial COI sequences were compared to those of other species deposited in GenBank. The sequences were assessed in the NEBCutter program to determine restriction sites in the sequence and the enzymes to be tested. Phenetic analysis performed by Neighbor-Joining method showed that the specimens sampled belong to two species preliminary identified here as G. cf. sylvius and G. cf. cuia, with G. cf. sylvius accounting for 95.2% of the individuals sampled. The enzymes NlaIII and SacI generated fragments that allowed distinguishing the Gymnotus species using PCR-RFLP. This analysis can be used to accurately identify these species, which is fundamental for monitoring Gymnotus fishing and assessing the conservation of this genetic resource.
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revision of Gymnotus gymnotiformes gymnotidae from the upper madeira basin of bolivia and peru with descriptions of two new species
Zootaxa, 2018Co-Authors: Jack M Craig, William G. R. Crampton, Vanessa Correaroldan, Hernan Ortega, James S AlbertAbstract:Banded Knifefishes ( Gymnotus , Gymnotidae) comprise the most species-rich genus of Neotropical electric fishes, with 41 species currently described from throughout the humid Neotropics, from Mexico to Argentina. Despite substantial alpha-taxonomic work in recent years, the diversity of Gymnotus in some regions remains poorly understood. Here we describe the Gymnotus fauna of the Upper Madeira basin of Bolivia and Peru from examination of more than 240 adult specimens. Species are delimited and described using body proportions (traditional morphometrics), fin-ray, squamation and laterosensory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteological traits, and color patterns. Comparisons of standardized linear measures as well as multivariate statistical methods validate the presence in the Upper Madeira basin of three previously described species, two with wide-spread geographic distributions throughout Greater Amazonia ( G. carapo and G. coropinae ), and one ( G. chaviro ) endemic to southwestern Amazonia. We also diagnose and describe two new species that are endemic to the Upper Madeira basin: G. eyra n. sp., morphologically most similar to G. mamiraua from lowland Amazonia, and G. riberalta n. sp., morphologically most similar to G. pantanal from the Paraguay-Parana basin. The five Gymnotus species from the Upper Madeira basin are not monophyletic, each species being more closely related to a different species from another region; i.e. the Gymnotus species from the Upper Madeira represents a polyphyletic assemblage. These descriptions to 43 the number of valid Gymnotus species.
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Redescription of the Tuvirão, Gymnotus inaequilabiatus Valenciennes, 1839, Using High-Resolution X-ray Computed Tomography
Copeia, 2014Co-Authors: Emmanuel L. Maxime, James S AlbertAbstract:The tuvirao (Gymnotus inaequilabiatus) attains the largest body size (c. 1 m) of any species within Gymnotus, and the type specimen is the largest known specimen of the genus. Gymnotus inaequilabiatus is one of several species in Gymnotus that often have been misidentified or mistaken for one another, in part because of their similar external appearance and their overlapping geographic ranges in southern Brazil and northern Argentina. Here we redescribe G. inaequilabiatus using conventional osteological and morphological tools, and also High Resolution X-Ray Computed Tomography of the 184-year-old type specimen of the species. We report characters showing that this species is a member of the G. tigre species group, rather than the G. carapo species complex, as had previously been believed. We also provide a detailed description of the cranial osteology of the large-bodied type specimen, which represents the greatest extent of hypermorphosis known in the Gymnotus. O tuvirao (Gymnotus inaequilabiatus) e a m...
William G. R. Crampton - One of the best experts on this subject based on the ideXlab platform.
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two new species of Gymnotus gymnotiformes gymnotidae from brazil and historical biogeography of the subgenus lamontianus
Copeia, 2020Co-Authors: Lesley Y Kim, William G. R. Crampton, James S AlbertAbstract:Gymnotus is the most species-rich and geographically widespread genus of gymnotiform electric fishes and has been widely explored to understand mechanisms of diversification in Neotropical freshwater fishes at a continental scale. Within Gymnotus, the subgenus Lamontianus is a phenotypically distinctive clade with an elongate, cylindrical body shape currently known from four valid species (G. anguillaris, G. cataniapo, G. pedanopterus, and G. tiquie) restricted to rivers draining the Guiana Shield. Here we use aspects of body-surface coloration, meristic, morphological, and osteological data, including cranial, laterosensory pore, and postcranial characters, to diagnose two new species of Lamontianus that inhabit the Aripuana and Arapiuns rivers that drain the Brazilian Shield. We also use geometric morphometric analyses of head shape to separate the new species from one another and other species of Lamontianus. We report biogeographic distributions for all species of Lamontianus and estimate ancestral geographic ranges and range evolution using the parametric biogeographic program BioGeoBEARS. We use the phylogeny of Lamontianus to test alternative hypotheses regarding lineage divergence times, before or after the formation of the modern East-draining Amazon at c. 10 Ma. Our analysis suggests that diversification in Lamontianus occurred primarily by geographic range fragmentation (vicariance) from an ancestral species distributed across the Western Guiana Shield. These results are similar to those of other Gymnotus and gymnotiform clades, where allopatric speciation and secondary contact due to geographic range expansion are commonly observed. This study brings to 46 the number of valid species of the genus Gymnotus, and to six the number of valid species of the subgenus Lamontianus.
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sexual size dimorphism in the macana tigrina Gymnotus javari gymnotidae gymnotiformes
Copeia, 2019Co-Authors: Aaron H Fronk, William G. R. Crampton, Jack M Craig, Lesley Y Kim, James S AlbertAbstract:Gymnotiform electric fishes exhibit many forms of sexual dimorphism, including sexual size dimorphism (SSD), aspects of head, jaw, and electric organ morphology, and electric signal waveform. However, sexual dimorphism is poorly documented in banded electric fishes (Gymnotus), where most species are monomorphic in external appearance and electric signal waveforms. Gathering comparative data on species of Gymnotus has historically been hampered by their predatory and territorial lifestyles, in that they are usually dispersed in their preferred habitats and often collected individually. Here data are presented from a population of G. javari from the Peruvian Amazon, examined for SSD (n = 55) and electric organ discharge (EOD) amplitude (n = 162). These results are compared with a syntopic population of G. carapo (n = 61), and also with G. omarorum (n = 24) from a population in Uruguay. Unlike most congeners, G. javari exhibits pronounced sexual dimorphism in total length and body weight, and EOD pulse amplitude is correlated with total length. A review of several ecological hypotheses on body-size distributions of each sex as a balance of multiple competing selection pressures finds none of these hypotheses adequately explain SSD in G. javari. Examining SSD in biogeographic and phylogenetic contexts leads to the conclusion that selection across different environments (e.g., local habitats, geographic regions) and through evolutionary time may have contributed to the evolution of SSD in some but not all lineages of Gymnotus.
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revision of Gymnotus gymnotiformes gymnotidae from the upper madeira basin of bolivia and peru with descriptions of two new species
Zootaxa, 2018Co-Authors: Jack M Craig, William G. R. Crampton, Vanessa Correaroldan, Hernan Ortega, James S AlbertAbstract:Banded Knifefishes ( Gymnotus , Gymnotidae) comprise the most species-rich genus of Neotropical electric fishes, with 41 species currently described from throughout the humid Neotropics, from Mexico to Argentina. Despite substantial alpha-taxonomic work in recent years, the diversity of Gymnotus in some regions remains poorly understood. Here we describe the Gymnotus fauna of the Upper Madeira basin of Bolivia and Peru from examination of more than 240 adult specimens. Species are delimited and described using body proportions (traditional morphometrics), fin-ray, squamation and laterosensory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteological traits, and color patterns. Comparisons of standardized linear measures as well as multivariate statistical methods validate the presence in the Upper Madeira basin of three previously described species, two with wide-spread geographic distributions throughout Greater Amazonia ( G. carapo and G. coropinae ), and one ( G. chaviro ) endemic to southwestern Amazonia. We also diagnose and describe two new species that are endemic to the Upper Madeira basin: G. eyra n. sp., morphologically most similar to G. mamiraua from lowland Amazonia, and G. riberalta n. sp., morphologically most similar to G. pantanal from the Paraguay-Parana basin. The five Gymnotus species from the Upper Madeira basin are not monophyletic, each species being more closely related to a different species from another region; i.e. the Gymnotus species from the Upper Madeira represents a polyphyletic assemblage. These descriptions to 43 the number of valid Gymnotus species.
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ral ssBioMed CentBMC Genetics Open AcceResearch article
2016Co-Authors: Susana Suely Rodrigues Milhomem, William G. R. Crampton, Jaime Ribeiro Carvalho, Julio C Pieczarka, Danillo S Silva, De Souza, Cleusa Y, Cleusa Y. NagamachiAbstract:Background: In this study we examined the karyotypes of morphologically indistinguishable populations of the electric knifefish Gymnotus carapo sensu stricto from the Eastern Amazon of Brazil. These were identified unambiguously on the basis of external morphology, meristics, and pigmentation. Results: Specimens from one of five localities exhibited a karyotype previously not documented for Gymnotus species in the Amazon basin: 2n = 40 (34M/SM+6ST/A). Samples from the other four localities exhibited a different karyotype: 2n = 42 (30M/SM+12ST/A), which we had previously described. Specimens from all five localities presented constitutive heterochromatin in the centromeric region of almost all chromosomes, including in the distal and interstitial regions. Staining with 4'6-Diamidino-2-phenylindole revealed C-positive banding. In both karyotypes the Nucleolar Organizer Region (NOR) was located on the short arm of pair 20, and Chromomycin A3 stained the NORs. Fluorescent in situ hybridization with telomeric probes showed an Interstitial Telomeric Sequence (ITS) in the proximal short arm of a metacentric pair in the 2n = 40 karyotype. Conclusion: The difference between the two karyotypes on the diploid number and chromosom
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Bayesian inference phylogeny for Brachyhypopomus based on rag2.
2016Co-Authors: William G. R. Crampton, Carlos David De Santana, Joseph C. Waddell, Nathan R LovejoyAbstract:Bayesian posterior probabilities shown by nodes (not shown for intraspecific relationships). Branch lengths proportional to substitutions per site. Terminal taxa are 85 individuals representing 26 species of Brachyhypopomus and 17 individuals representing 9 outgroup taxa. Branch lengths for Gymnotus and Sternopygus (represented with dashed lines) are reduced. See Table 3 for list of sequenced specimens. Terminal two letter codes refer to the drainage units described in ‘Geographic and ecological distributions’ (Materials and Methods).
Reynaldo D. Pinto - One of the best experts on this subject based on the ideXlab platform.
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automatic realistic real time stimulation recording in weakly electric fish long time behavior characterization in freely swimming fish and stimuli discrimination
PLOS ONE, 2014Co-Authors: Caroline Garcia Forlim, Reynaldo D. PintoAbstract:Weakly electric fish are unique model systems in neuroethology, that allow experimentalists to non-invasively, access, central nervous system generated spatio-temporal electric patterns of pulses with roles in at least 2 complex and incompletely understood abilities: electrocommunication and electrolocation. Pulse-type electric fish alter their inter pulse intervals (IPIs) according to different behavioral contexts as aggression, hiding and mating. Nevertheless, only a few behavioral studies comparing the influence of different stimuli IPIs in the fish electric response have been conducted. We developed an apparatus that allows real time automatic realistic stimulation and simultaneous recording of electric pulses in freely moving Gymnotus carapo for several days. We detected and recorded pulse timestamps independently of the fish’s position for days. A stimulus fish was mimicked by a dipole electrode that reproduced the voltage time series of real conspecific according to previously recorded timestamp sequences. We characterized fish behavior and the eletrocommunication in 2 conditions: stimulated by IPIs pre-recorded from other fish and random IPI ones. All stimuli pulses had the exact Gymontus carapo waveform. All fish presented a surprisingly long transient exploratory behavior (more than 8 h) when exposed to a new environment in the absence of electrical stimuli. Further, we also show that fish are able to discriminate between real and random stimuli distributions by changing several characteristics of their IPI distribution.
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Automatic Realistic Real Time Stimulation/Recording in Weakly Electric Fish: Long Time Behavior Characterization in Freely Swimming Fish and Stimuli Discrimination
2014Co-Authors: Caroline Garcia Forlim, Reynaldo D. PintoAbstract:Weakly electric fish are unique model systems in neuroethology, that allow experimentalists to non-invasively, access, central nervous system generated spatio-temporal electric patterns of pulses with roles in at least 2 complex and incompletely understood abilities: electrocommunication and electrolocation. Pulse-type electric fish alter their inter pulse intervals (IPIs) according to different behavioral contexts as aggression, hiding and mating. Nevertheless, only a few behavioral studies comparing the influence of different stimuli IPIs in the fish electric response have been conducted. We developed an apparatus that allows real time automatic realistic stimulation and simultaneous recording of electric pulses in freely moving Gymnotus carapo for several days. We detected and recorded pulse timestamps independently of the fish’s position for days. A stimulus fish was mimicked by a dipole electrode that reproduced the voltage time series of real conspecific according to previously recorded timestamp sequences. We characterized fish behavior and the eletrocommunication in 2 conditions: stimulated by IPIs pre-recorded from other fish and random IPI ones. All stimuli pulses had the exact Gymontus carapo waveform. All fish presented a surprisingly long transient exploratory behavior (more than 8 h) when exposed to a new environment in the absence of electrical stimuli. Further, we also show that fish are abl
Julio Cesar Pieczarka - One of the best experts on this subject based on the ideXlab platform.
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Gymnotus coatesi gymnotiformes a case of colocation of multiple sites of 18s rdna with telomeric sequences
Zebrafish, 2017Co-Authors: Milla De Andrade Machado, Julio Cesar Pieczarka, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomempaixao, Cleusa Yoshiko NagamachiAbstract:Abstract Gymnotus coatesi is a small and rare species of banded knife fish that was originally described by LaMonte in 1935, found along the main stretch of the Amazon River. There is no described ...
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pintura cromossomica em Gymnotus arapaima com sonda e cromossomo total de Gymnotus carapo gymnotiformes gymnotidae
Semina-ciencias Agrarias, 2017Co-Authors: Milla De Andrade Machado, Julio Cesar Pieczarka, Fernando Henrique Ramos Silva, P C M Obrien, Malcolm Andrew Ferguson Smith, Cleusa Yoshiko NagamachiAbstract:O genero Gymnotus e um dos generos mais especiosos (40 especies) e mais amplamente distribuidos nas aguas continentais da America do Sul, com maior ocorrencia na bacia amazonica, onde varias especies ocorrem em simpatria. A citogenetica tem sido uma importante ferramenta na citotaxinomia e na elucidacao dos processos evolutivos no genero, que possui uma diversidade cariotipica elevada, sendo os cariotipos especie-especificos, mesmo nas especies que possuem o mesmo numero diploide e sao um fator de isolamento reprodutivo pre-zigotico nas especies em simpatria. Cromossomos metafasicos de Gymnotus arapaima (GAR, 2n=44, FC: 24 m/sm + 20 st/a) foram hibridizados com sondas de cromossomo total de Gymnotus carapo (GCA, 2n=42). A sonda da regiao 1 (GCA 20) hibridizou um unico cromossomo, o GAR 19, portador da NOR. As sondas da regiao 2 (GCA 1, 2, 3 e 16) hibridizaram os cromossomos de GAR: 1, 2, 14 e 18 e 21, o braco curto do par 4 e braco curto e uma parte do braco longo do par 13. As da regiao 3 (GCA 4, 5, 6, 7, 8, 17, 18, 19) hibridizaram os cromossomos de GAR 3, 5, 6, 5, 16, 20 e 22, o braco longo do par 4 e parte do braco longo do par 13. As da regiao 4 (GCA 9 – 15 e 21) hibridizaram os cromossomo 7-12 e 17. Ate a presente analise pelo menos 3 pares (GAR 1, 16 e 20) se encontram conservados em relacao ao cariotipo de GCA, enquanto outros encontram-se fragmentados e/ou fusionados. A pintura cromossomica em Gymnotus e uma ferramenta recente que, como observado no cariotipo analisado e em trabalhos anteriores, vem mostrando que os rearranjos cromossomicos no genero sao numerosos e o processo evolutivo dinâmico.
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Are NORs Always Located on Homeologous Chromosomes? A FISH Investigation with rDNA and Whole Chromosome Probes in Gymnotus Fishes (Gymnotiformes)
2016Co-Authors: Susana Suely Rodrigues Milhomem, Fausto Foresti, Julio Cesar Pieczarka, Priscilla Cardim Scacchetti, Patricia C. M. O’brien, Malcolm A. Ferguson-smith, Jose ́ C. Pansonato-alves, Cleusa Y. NagamachiAbstract:Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs ar
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Chromosome painting reveals multiple rearrangements between Gymnotus capanema and Gymnotus carapo (Gymnotidae, Gymnotiformes).
Cytogenetic and genome research, 2013Co-Authors: Cleusa Yoshiko Nagamachi, Susana Suely Rodrigues Milhomem, Julio Cesar Pieczarka, Jéssica Almeida Batista, Patricia Caroline Mary O’brien, M. A. Ferguson-smithAbstract:The genus Gymnotus (Gymnotiformes) is a group of fishes with karyotypic plasticity, demonstrated by cytogenetic studies using whole chromosome probes of G. carapo (GCA, 2n = 42) that were obtained by flow-sorting from fibroblast cultures. In the present work we undertook comparative mapping of the karyotype of G. capanema (GCP, 2n = 34) with GCA, 2n = 42 painting probes. The results demonstrate that the karyotype of G. capanema is extensively rearranged when compared to G. carapo. From the 12 chromosome pairs of G. carapo that can be individually differentiated (GCA1-3, 6, 7, 9, 14, 16 and 18-21), only 4 pairs (GCA6, 7, 19, and 20) maintained conserved synteny in G. capanema. From these 4, GCA6 and GCA20 correspond to individual chromosomes (GCP8 and GCP15), while the other 2 share homology with parts of GCP1 and GCP2, respectively. The remaining GCP chromosomes showed more complex hybridization patterns with homologies to other GCA pairs. These results demonstrate that the level of reorganization in the genome of G. capanema is much greater than in GCA, 2n = 42 and in karyomorph GCA, 2n = 40 which was previously analyzed by chromosome painting.
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Profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (Gymnotiformes) from the Eastern Amazon
Genetics and molecular biology, 2013Co-Authors: Karina Motta Melo, Julio Cesar Pieczarka, Cleusa Yoshiko Nagamachi, Ingrid Reale Alves, José Augusto De Oliveira David, Cesar Koppe GrisoliaAbstract:The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities.