Abstract Neotropical fishes emerge as an extremely diverse group of vertebrates where genomic strategies to evaluate structural and functional features are still beginning. Here, we present a second draft genome of Apareiodon sp. (2n=54, ZZ/ZW), adding PacBio technology whole genome sequencing, and assembling by combining two technologies (long and short reads). Using a detailed strategy for genome assembly with fish genomes of Pygocentrus nattereri, Carassius auratus, and Astyanax mexicanus as references, the final assembly of the Apareiodon sp. genome generated 93 scaffolds, an N50 of 37,200,078 bases, and a size estimate considering 28 scaffolds (26 autosomes+ZW) of ~945 Mb. In Apareiodon sp., this second genome draft confirmed that ~36% of the genome is composed of repetitive DNA. Furthermore, the new draft genome has improved genomic quality assessments, allowing the annotation of 36,290 genes and 15,683 proteins, which presented similarities to reference genomes. The second draft genome of Apareiodon sp. will be useful for research on integrative cytogenetic and genomic data. It will open perspectives for analyzing sex-determining genes in Neotropical fish with a ZZ/ZW sex chromosome system. beginning Here sp 2n=54, 2n54 n 2n 54 (2n=54 ZZ/ZW, ZZZW , ZZ ZW ZZ/ZW) sequencing long reads. reads . reads) nattereri auratus references 9 N N5 37200078 37 200 078 37,200,07 bases 2 26 (2 autosomes+ZW autosomesZW autosomes 945 ~94 Mb 36 ~36 DNA Furthermore assessments 36290 290 36,29 15683 15 683 15,68 proteins data sexdetermining determining system 2n=54 2n5 5 (2n=5 3720007 3 20 07 37,200,0 ( 94 ~9 ~3 3629 29 36,2 1568 1 68 15,6 2n=5 (2n= 372000 0 37,200, ~ 362 36, 156 6 15, 2n= (2n 37200 37,200 3720 37,20 372 37,2 37,

RESUMO Objetivo: Avaliar o equilíbrio e a qualidade de vida em pacientes submetidos a artroplastia total do joelho por gonartrose primária. Método: Pacientes com 60 anos ou mais foram avaliados em relação ao equilíbrio e à qualidade de vida antes da artroplastia total de joelho e seis meses após a cirurgia. Para avaliar o equilíbrio, foi usado o teste da Escala Motora para a Terceira Idade; para avaliar a qualidade de vida, foram usados os questionários Western Ontario and McMaster Universities Osteoarthritis Index e Short Form Health Survey. Um grupo controle de indivíduos saudáveis, pareado por idade e gênero, foi usado para comparação dos níveis de equilíbrio do grupo em estudo após a cirurgia. Resultados: Completaram o estudo 28 pacientes, em 37 artroplastias. A média de idade foi de 70,18 ± 6,17 anos. Em todas as variáveis analisadas, observou-se significância estatística (p ≤ 0,05) para melhoria do equilíbrio e da qualidade de vida após a artroplastia. Observou-se que, após artroplastia do joelho, o nível de equilíbrio não alcança o nível esperado para indivíduos saudáveis (p ≤ 0,05). Conclusão: A artroplastia total de joelho é capaz de melhorar o equilíbrio seis meses após a cirurgia, bem como todos os domínios da qualidade de vida. No entanto, não é capaz de restaurar o equilíbrio comparável àquele dos indivíduos saudáveis.

ABSTRACT Objective: To evaluate the change in balance and quality of life in patients undergoing total knee arthroplasty for primary gonarthrosis. Method: Patients aged 60 years or older were evaluated in relation to the balance and quality of life before total knee arthroplasty and six months after surgery. To assess balance, this study used the Motor Scale Test for the Elderly; quality of life was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire and the Short Form Health Survey. A control group consisting of healthy adults, age- and gender-paired, was used to compare the balance after surgery results. Results: Twenty-eight patients completed the study, of a total of 37 arthroplasties. The mean age was 70.18 ± 6.17 years. All variables were statistically significant (p ≤ 0.05) for improved balance and quality of life after arthroplasty. It was observed that, after knee arthroplasty, the level of balance does not reach that expected for healthy individuals (p ≤ 0.05). Conclusion: Total knee arthroplasty is effective at improving balance six months after surgery, as well as all domains of quality of life. However, it is not able to restore balance to a level comparable to that of healthy individuals.

RESUMO O estudo das estratégias e ações da industrialização de pescado permite apreender as tensões entre ritmos naturais (estoques transformados em matérias-primas) e sociais, representados pelas empresas, pelo Estado e o trabalho. texto problematiza as transformações territoriais e as estratégias de grupos econômicos mundiais com centros de gestão na Comunidade Autônoma da Galícia na Espanha. Essas estratégias empresariais colocam a Espanha entre os maiores produtores mundiais de pescado industrializado e minimizam os problemas de acesso às matérias-primas, os conflitos trabalhistas, a concorrência internacional, inclusive em relação às redes comerciais com as marcas próprias. As empresas investem em pesquisas, em propaganda, na diversificação dos produtos e no reconhecimento da Galícia como potência marítima. Os processos de transformação territorial são: a centralização de capitais em um número menor de empresas; a externalização de fases do processo produtivo para a América Latina e África; a separação dos centros de gestão e das fábricas localizadas nas antigas áreas industriais; o aumento da mecanização que intensifica os conflitos com a organização dos trabalhadores do setor.

ABSTRACT The study of the strategies and actions related to fishing industrialization enables the understanding of the tension between natural rhythms (stocks transformed into raw material) and social ones, represented by companies, the State and work. This paper problematizes the territorial changes and strategies of world economic groups in management centers in the Autonomous Community of Galicia in Spain. These corporate strategies place Spain as one of the largest producers of industrialized fishing in the world and have mitigated problems related to the access to raw material, labor conflicts, international competition and commercial chains that have their own trademarks. Companies invest in research, advertising, product diversification and the recognition of Galicia as a maritime power. The processes of territorial transformation are: the centralization of capital in a smaller number of companies; the externalization of phases of the productive process to Latin America and Africa; the separation of management centers and factories located in the old industrial areas; and the increase in mechanization that intensifies conflicts with the workers’ organization of the sector.

RESUMEN El estudio de las estrategias y acciones de la industrialización de pescado permite aprehender las tensiones entre ritmos naturales (stocks transformados en materias primas) y sociales, representados por las empresas, por el Estado y el trabajo. El texto problematiza las transformaciones territoriales y las estrategias de grupos económicos mundiales con centros de gestión en la Comunidad Autónoma de Galicia en España. Estas estrategias empresariales colocan a España entre los mayores productores mundiales de pescado industrializado y minimizan los problemas de acceso a las materias primas, los conflictos laborales, la competencia internacional, incluso en relación con las redes comerciales con las marcas propias. Las empresas invierten en investigaciones, en propaganda, en la diversificación de los productos y en el reconocimiento de Galicia como potencia marítima. Los procesos de transformación territorial son: la centralización de capitales en un número menor de empresas; la externalización de fases del proceso productivo para América Latina y África; la separación de los centros de gestión y de las fábricas ubicadas en las antiguas áreas industriales; el aumento de la mecanización que intensifica los conflictos con la organización de los trabajadores del sector.

RESUMO O uso de dressadores desgastados pode proporcionar uma menor agressividade para o rebolo, causando um aumento das forças de corte e a perda mais rápida de afiação dos grãos que por consequência compromete a qualidade final da peça a ser usinada. Por outro lado, um método de monitoramento do processo de dressagem em tempo real, que permita identificar o momento em que o dressador esteja desgastado, e assim seja substituído, é algo que pode ser de grande importância para o processo de retificação, visando garantir a qualidade e precisão das peças usinadas. Dessa forma, esse trabalho teve como objetivo avaliar o desgaste do dressador de ponta única, por meio da análise espectral do sinal de vibração durante o processo de dressagem. Para isso, ensaios de dressagem foram realizados, utilizando uma retificadora plana e variáveis de entrada um rebolo de óxido de alumínio, um dressador de ponta única de diamante sintético do tipo CVD (Chemical Vapour Deposition), profundidade de dressagem de 40 µm; velocidade do dressador de 3,45 mm/s e o grau de recobrimento Ud igual a 1 no início da dressagem. As variáveis de saída foram a aquisição dos sinais de vibração por meio de um acelerômetro fixo no suporte do dressador, coletados por um osciloscópio e as medições do desgaste do dressador por meio de um microscópio. Por meio da análise espectral do sinal de vibração, em três condições de uso, sendo, nova, meia vida e desgastado, utilizando o método Welch e a Transformada Rápida de Fourier (FFT), foi possível identificar faixas de frequência entre 1 kHz e 8 kHz, em que a amplitude aumentava em função do desgaste do dressador. Foi constatado que o aumento da atividade de vibração é diretamente proporcional ao desgaste do dressador CVD. Foi possível identificar faixas de frequências que melhor caracterizam tal situação, como nos trechos de 2 kHz a 4 kHz e de 6 kHz e 8 kHz. Os resultados indicam a possibilidade de implementação de um sistema de monitoramento em tempo real, a partir do uso de filtros digitais nessas faixas de frequência.

ABSTRACT The use of dressers worn can provide a less aggressive to the grinding wheels, causing an increase in cutting forces and a more rapid loss of grinding grain consequently compromise the final quality of the workpiece to be machined. On the other hand, a method of monitoring the dressing operation in real time, identifying the moment in which the dresser is worn and thus to be replaced, something which can be of great importance for the grinding process in order to assure quality and accuracy of the workpieces. Thus, this study aimed to evaluate the wear of the single point dresser, through spectral analysis of vibration signal during the dressing operation. For this dressing assays were performed using a flat grinding and input variables a grinding wheel aluminum oxide, one the single point dresser of synthetic diamond r type CVD (Chemical Vapour Deposition), depth of dressing 40 µm, dresser speed of 3.45 mm /s and the degree of coating Ud equal to 1 at the beginning of dressing. The output variables were the acquisition of the vibration signals via an accelerometer fixed in the dresser holder, collected by an oscilloscope and dresser wear measurements using a microscope. Through spectral analysis of vibration signal in three conditions of use, and, new, half-life and worn, using the Welch method and Fast Fourier Transform (FFT), it was possible to identify the frequency bands between 1 kHz and 8 kHz in the amplitude increased according to the dresser wear. It has been found that the increased vibration activity is directly proportional to the CVD dresser wear. It was possible to identify frequency bands that best characterize such a situation, as in bands of 2 kHz to 4 kHz and 6 kHz and 8 kHz. The results indicate the possibility of implementing a real-time monitoring system, from the use of digital filters in these frequency bands.

The genus Phanaeus is included in the tribe Phanaeini, one of the most diverse tribes within the subfamily Scarabaeinae in terms of chromosomal characteristics. However, so far the species of this genus were not studied with differential cytogenetic techniques, limiting any inference of the probable mechanisms responsible for this diversity. In this work, several techniques were applied with the aim of cytogenetically characterizing two Phanaeus species. The karyotype found for Phanaeus (Notiophanaeus) chalcomelas was 2n = 12, neo-XY, and that of P. (N.) splendidulus was 2n = 20, Xy p, considered primitive for the family Scarabaeidae. The chromosomes of both species showed a high amount of constitutive heterochromatin (CH), with blocks rich in base pairs GC (CMA3+). Moreover, in P. (N.) chalcomelas the marks revealed by C-banding and fluorochrome staining were different in size, showing CH variability. Sites of 18S ribosomal DNA (rDNA) were identified in one autosomal pair of P. (N.) chalcomelas and in five autosomal pairs of P. (N.) splendidulus. On the other hand, only one autosomal pair exhibited 5S rDNA sequences in these species. The results suggest that the karyotype differentiation of the Phanaeus species studied here involved pericentric inversions and centric fusions, as well as mechanisms related to amplification and dispersion of CH and rDNA sequences.

JUSTIFICATIVA E OBJETIVOS: A indução da anestesia geral em pacientes com "estômago cheio" pode resultar em regurgitação do conteúdo gástrico e aspiração pulmonar. A indução em sequência rápida (ISR) tem a função de minimizar o intervalo de tempo entre a perda dos reflexos protetores da via aérea e intubação traqueal com um tubo com balonete. O objetivo desse estudo foi avaliar a execução da indução em sequência rápida entre os anestesiologistas do Hospital São Paulo. MÉTODO: Os participantes responderam o questionário de forma voluntária e anônima, após esclarecimento e livre consentimento. O questionário continha 60 questões acerca dos pontos fundamentais da ISR. As questões se dividiam em pré-oxigenação, circuitos, drogas utilizadas na indução (opioides, hipnóticos, bloqueadores neuromusculares), técnicas de pressão cricoide, intubação e intubação difícil. RESULTADOS: Foram aplicados 75 questionários, sendo 22 descartados por preenchimento incompleto. Todos anestesiologistas declaram sempre realizar pré-oxigenação e administrar opioide, hipnótico e bloqueador neuromuscular. A maioria utiliza fentanila (83%), propofol (74,5%) e succinilcolina (68,6%). Todos anestesiologistas realizam pressão cricoide. A maioria não soube a pressão correta a ser aplicada na cartilagem cricoide. As falhas de intubação já ocorreram com 71,7% dos anestesiologistas e com 40% a regurgitação. Diante de uma intubação difícil e inesperada, 35,5% dos anestesiologistas solicitam máscara laríngea. CONCLUSÕES: Este estudo mostrou uma ampla variedade individual na técnica da ISR, fato já relatado por diversos autores. A dificuldade em se estabelecer um protocolo de ISR pode ser atribuída às constantes evidências que a ciência proporciona, fazendo da atualização parte da boa prática médica ao longo dos tempos.

BACKGROUND AND OBJECTIVES: The induction of the general anesthesia in patients on "a full stomach" can result in regurgitation of the gastric content and pulmonary aspiration. The function of the rapid sequence induction (RSI) is to minimize the time interval between the loss of the airway protection reflexes and tracheal intubation tube balloon. The objective of this study was to evaluate the rapid sequence induction among the anesthesiologists of the São Paulo Hospital. METHODS: The participants answered the questionnaire voluntarily and anonymously, after signed consent. The questionnaire consisted of 60 questions about the fundamental points of the RSI. The questions were divided in pre-oxygenation, circuits, drugs used in the induction (opioids, hypnotics, neuromuscular blockers), cricoid pressure techniques, intubation and difficult intubation. RESULTS: Seventy-five questionnaires were applied and 22 were discarded due to incomplete answering. All anesthesiologists always declare doing pre-oxygenation and administering opioid, hypnotic, and neuromuscular blocker. Most use fentanyl (83%), propofol (74.5%) and succinylcoline (68.6%). All anesthesiologists apply cricoid pressure. Most did not know the correct pressure to be applied on the cricoid cartilage. Intubation failures have already occurred with 71.7% of anesthesiologists and with 40%, the regurgitation. When faced with an unexpected difficult intubation, anesthesiologists ask for the laryngeal mask (35.5%). CONCLUSIONS: This study showed a broad individual variety of the RSI technique, a fact already reported by different authors. The difficulty in establishing a RSI protocol can be attributed to constant evidence that science provides us, where updating over the years becomes good medical practice.

JUSTIFICATIVA Y OBJETIVOS: La inducción de la anestesia general en pacientes con "estómago lleno" puede resultar en una regurgitación del contenido gástrico y en la aspiración pulmonar. La inducción en secuencia rápida (ISR), tiene la función de minimizar el intervalo de tiempo entre la pérdida de los reflejos protectores de la vía aérea y la intubación traqueal con un tubo con balón. El objetivo de este estudio, fue evaluar la ejecución de la inducción en secuencia rápida entre los anestesiólogos del Hospital São Paulo. MÉTODO: Los participantes respondieron al cuestionario de forma voluntaria y anónima, con la pertinente clarificación y con la posterior firma del Término de Consentimiento Informado. El cuestionario contenía 60 preguntas sobre los puntos fundamentales de la ISR. Las preguntas se dividían en preoxigenación, circuitos, fármacos utilizados en la inducción (opioides, hipnóticos, bloqueantes neuromusculares), técnicas de presión cricoide, intubación y desentubación difícil. RESULTADOS: Se aplicaron 75 cuestionarios y de ellos, 22 se descartaron porque fueron rellenados de forma incompleta. Todos los anestesiólogos siempre realizan una preoxigenación y siempre administran opioide, hipnótico y bloqueante neuromuscular. La mayoría utiliza fentanila (83%), propofol (74,5%) y succinilcolina (68,6%). Todos los anestesiólogos realizan presión cricoide. La mayoría no tuvo conocimiento respecto de la presión correcta que sería aplicada en el cartílago cricoide. Los fallos de intubación ya ocurrieron con un 71,7% de los anestesiólogos y con un 40% la regurgitación. Frente a una intubación difícil e inesperada los anestesiólogos solicitan mascarilla laríngea (35,5%). CONCLUSIONES: Este estudio mostró una amplia variedad individual en la técnica de la ISR, hecho que ya fue relatado por diversos autores. La dificultad en establecer un protocolo de ISR puede ser atribuida a las constantes evidencias que la ciencia nos proporciona, haciendo con que la actualización forme parte de la buena práctica médica a lo largo de los tiempos.

OBJETIVO: Avaliar as técnicas de banda dupla e banda simples para reconstrução anatômica do ligamento cruzado anterior do joelho e comprovar que a técnica de dupla banda, além de fornecer maior estabilidade anterior, também causa menor dor e uma melhor resposta subjetiva do paciente. MÉTODOS: Selecionamos 42 pacientes que foram submetidos à reconstrução do LCA, conforme a técnica de reconstrução anatômica por banda simples com enxerto de tendões flexores com dois túneis ou reconstrução anatômica por banda dupla e quatro túneis com enxerto de tendões dos músculos semitendíneo e gracilis. Todas as fixações foram realizadas com parafusos de interferência. Não houve variação na amostra, avaliou-se no pré-operatório IKDC objetivo, subjetivo, Lysholm e tempo de lesão. Reavaliou-se após seis meses todas as variáveis anteriormente citadas, incluindo o KT-1000 correlacionando o joelho contralateral. RESULTADOS: Não houve diferença significativa entre os dois grupos nas avaliações subjetivas, mas na amplitude de movimento, nas avaliações objetivas, incluindo o KT-1000 (com significância estatística), o grupo da banda simples anatômica obteve melhores resultados. CONCLUSÃO: Nosso estudo demonstra que não obtivemos diferença entre os dois grupos nas avaliações subjetivas, porém nas avaliações objetivas observamos melhores resultados na técnica por banda simples anatômica.

OBJECTIVE: To evaluate the double-band and single-band techniques for anatomical reconstruction of the anterior cruciate ligament of the knee and demonstrate that the double-band technique not only provides greater anterior stability but also causes less pain and a better subjective patient response. METHODS: We selected 42 patients who underwent anterior cruciate ligament reconstruction, by means of either the single-band anatomical reconstruction technique, using flexor tendon grafts with two tunnels, or the double-band anatomical reconstruction technique, using four tunnels and grafts from the semitendinosus and gracilis tendons. All fixations were performed using interference screws. There was no variation in the sample. Before the operation, the objective and subjective IKDC scores, Lysholm score and length of time with the injury were evaluated. All these variables were reassessed six months later, and the KT-1000 correlation with the contralateral knee was also evaluated. RESULTS: There was no significant difference between the two groups in subjective evaluations, but the single-band group showed better results in relation to range of motion and objective evaluations including KT-1000 (with statistical significance). CONCLUSION: Our study demonstrated that there was no difference between the two groups in subjective evaluations, but better results were found using the single-band anatomical technique, in relation to objective evaluations.

Uma análise qualitativa da variabilidade genética em Astyanax fasciatus (Cuvier, 1819) do alto Rio Tibagi e Parque Estadual de Vila Velha (PEVV) foi conduzida por digestão enzimática (RFLP) da região D-Loop do mtDNA. Os resultados evidenciaram que essas populações são geneticamente diferentes.

A preliminary qualitative analysis of genetic variability status in Astyanax fasciatus (Cuvier, 1819) from upper Tibagi River headwaters and Vila Velha State Park (VVSP) was carried out by enzymatic digestion (RFLP) of D-Loop region from mtDNA. The results showed that Tibagi and VVSP populations were genetically different.

No presente estudo três espécies de Lutjaninae, Lutjanus analis, L. griseus e L. synagris foram analisadas através da coloração convencional com Giemsa, banda C e coloração com nitrato de prata para identificar as Regiões Organizadoras de Nucléolo (NORs) ativas. Hibridação fluorescente in situ (FISH) foi também aplicada para estabelecimento do número e localização dos agrupamentos de genes ribossômicos (18S e 5S rRNA). A contagem de células metafásicas revelou um número diplóide modal de 48 cromossomos acrocêntricos em L. analis e L. griseus. Dois citótipos foram observados em L. synagris: citótipo I com 2n=48 cromossomos acrocêntricos, encontrado em 19 espécimes, e citótipo II com 46 cromossomos acrocêntricos e um grande metacêntrico, encontrado em dois espécimes. O grande metacêntrico, que possivelmente se originou por um rearranjo Robertsoniano, não está relacionado com o sexo. Nas três espécies a heterocromatina constitutiva está localizada nas regiões centroméricas de todos os cromossomos. NORs foram detectadas no braço curto de um único par cromossômico, número 24 em L. analis e número 6 em ambos os citótipos de L. synagris. Em L. griseus, um polimorfismo de número de NORs foi observado, após coloração com prata e por FISH, as fêmeas apresentaram um máximo de três NORs e os machos um máximo de seis NORs. Em todas as espécies os genes ribossômicos 5S foram encontrados em um único par cromossômico. Os dados obtidos, somados aos demais previamente publicados para cinco outras espécies de Lutjanidae, mostram que na família há uma homogeneidade cromossômica, porém também são encontrados cariótipos derivados, originados por rearranjos Robertsonianos, assim como pela ocorrência de sítios múltiplos e variados de NORs.

In the present study, three species of Lutjaninae, Lutjanus analis, L. griseus and L. synagris, were analyzed by conventional Giemsa staining, C-banding and silver staining, to reveal active Nucleolus Organizer Regions (NORs). Fluorescent in situ hybridization (FISH) was also applied to establish the number and location of the ribosomal gene clusters (18S and 5S rRNA genes). Counts of diploid metaphasic cells revealed a diploid modal chromosome complement composed of 48 acrocentric chromosomes in both L. analis and L. griseus. Two cytotypes were observed in L. synagris: cytotype I, with 2n=48 acrocentric chromosomes, found in 19 specimens, and cytotype II, with 46 acrocentric chromosomes and one large metacentric, found in two specimens. The large metacentric, which possibly originated from a Robertsonian rearrangement, was not found to be sex-related. In the three species, constitutive heterochromatin is located in the centromeres of all chromosomes. NORs were detected on the short arms of a single chromosome pair, number 24 in L. analis and number 6 in both cytotypes of L. synagris. In L. griseus, a polymorphism of the NORs number was detected, by both Ag-staining and FISH, as females show a maximum of three NORs, and males a maximum of six NORs. In all species, minor ribosomal genes were found located on a single chromosome pair. The obtained data, along with those previously reported for other five Lutjanidae species, show that a general chromosome homogeneity occurs within the family, but that derived karyotypes based on Robertsonian rearrangements as well as multiple and variable NORs sites can also be found.

Sharks are suffering from intensive exploitation by worldwide fisheries leading to a severe decline in several populations in the last decades. The lack of biological data on a species-specific basis, associated with a k-strategist life history make it difficult to correctly manage and conserve these animals. The aim of the present study was to develop a DNA-based procedure to discriminate shark species by means of a rapid, low cost and easily applicable PCR analysis based on 5S rDNA repeat units amplification, in order to contribute conservation management of these animals. The generated agarose electrophoresis band patterns allowed to unequivocally distinguish eight shark species. The data showed for the first time that a simple PCR is able to discriminate elasmobranch species. The described 5S rDNA PCR approach generated species-specific genetic markers that should find broad application in fishery management and trade of sharks and their subproducts.

Cytogenetic analyses were performed in Cyphocharax modestus, collected at Paranapanema River and Tietê River (São Paulo State, Brazil). A karyotype with 2n = 54 chromosomes was observed in the animals from both Brazilian freshwater river systems. One to four B chromosomes were also detected in individuals from the Paranapanema River, which represents the probable first report of more than a single supernumerary element in a species of the Curimatidae group. C-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of C. modestus. Moreover, while some B chromosomes were characterized by the complete absence of C-bands, others were totally heterochromatic. Although there was a prevalence of B chromosomes in males of C. modestus, at least one supernumerary element was found in males and/or females of several other populations of the species, which suggests that the presence of these chromosomes seems to represent a general trait of C. modestus. A possible origin of the described B chromosomes may be related to the occurrence of a chromosome non-disjunction followed by the loss of euchromatic segments, an event that should have occurred in chromosomes that present conspicuous centromeric heterochromatic blocks and even in chromosomes that lack C-bands in this region, resulting in small supernumerary elements.

Actin-encoding cDNAs of Nile tilapia (Oreochromis niloticus) were isolated by RT-PCR using total RNA samples of different tissues and further characterized by nucleotide sequencing and in silico amino acid (aa) sequence analysis. Comparisons among the actin gene sequences of O. niloticus and those of other species evidenced that the isolated genes present a high similarity to other fish and other vertebrate actin genes. The highest nucleotide resemblance was observed between O. niloticus and O. mossambicus a-actin and b-actin genes. Analysis of the predicted aa sequences revealed two distinct types of cytoplasmic actins, one cardiac muscle actin type and one skeletal muscle actin type that were expressed in different tissues of Nile tilapia. The evolutionary relationships between the Nile tilapia actin genes and diverse other organisms is discussed.

In order to extend the genetic data on the Sciaenidae fish family, the present study had the purpose to characterize PCR-generated 5S rDNA repeats of twelve species of this group through PAGE (Polyacrylamide Gel Electrophoresis) analysis. The results showed the occurrence of at least two different 5S rDNA size classes in all the species. Moreover, 5S rDNA repeats of one of the studied species - Isopisthus parvipinnis - were cloned and subjected to nucleotide sequencing and Southern blot membrane hybridization analyses, which permitted to confirm the existence of two major 5S rDNA classes. Phylogenetic analysis based on the nucleotide sequences of different 5S rDNA repeats of I. parvipinnis lead to their separation into two major clusters. These results may reflect the high dynamism that rules the evolution rate of 5S rDNA repeats. The obtained data suggest that 5S rDNA can be useful in genetic analyses to identify species-specific markers and determine relationships among species of the Sciaenidae group.

An alpha actin gene segment, isolated from Nile tilapia (Oreochromis niloticus), was characterized by nucleotide sequencing, predicted amino acid sequence and Southern blot hybridization. Genomic DNA amplification resulted in a 1063-bp fragment corresponding to a partial alpha-cardiac muscle actin gene containing exons 3 to 6. Southern blot analysis of the restriction-digested DNA revealed that the Nile tilapia genome contains multiple muscle actin isoforms. Although comparison of the nucleotide sequence, amino acid residues and exon-intron organization of the isolated actin gene with those of other vertebrates showed a high level of identity, diagnostic amino acid residues can still be correlated to distinct actin genes in fish species.

The 5S ribosomal DNA (5S rDNA) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5S rDNA coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (NTS). To contribute to knowledge on the organization and evolution of vertebrate 5S rDNA we used PCR, nucleotide sequencing, Southern blot hybridization and chromosome fluorescence in situ hybridization (FISH) to investigate 5S rDNA tandem repeats in the South American Curimatidae fish Steindachnerina insculpta and Cyphocharax modesta. 5S rDNA repeats of 180 base pairs (bp) from both species were PCR-generated and sequenced evidencing the shortest 5S rDNA monomer so far described in eukaryote species. Southern blotting revealed that both species contained two tandem 5S rDNA classes, the PCR amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by PCR. Chromosome mapping of the 5S rDNA repeats identified a major locus in both species and a second minor locus only in C. modesta. The Southern blot and chromosome mapping data indicate the presence of different types of 5S rDNA tandem repeats in the Curimatidae genome.