Showing papers by "Claudio Oliveira published in 2005"

Isolation and characterization of microsatellite loci in Pseudoplatystoma corruscans (Siluriformes : Pimelodidae) and cross-species amplification

Abstract: A total of five polymorphic microsatellites loci from Pseudoplatystoma corruscans were isolated and characterized. A population survey involving 43 specimens resolved a large number of alleles (range seven to eight among loci) and high observed heterozygosity (0.500–0.615), indicating its usefulness in population genetics studies. Cross-species amplification was successful in four other Pimelodidae species.

Development of species‐specific primers for the ectoparasitic nematode species Xiphinema brevicolle, X. diffusum, X. elongatum, X. ifacolum and X. longicaudatum (Nematoda: Longidoridae) based on ribosomal DNA sequences

Abstract: Summary The objective of this study was to develop single-step PCR species-specifi c primers that reliably discriminate four economically important Xiphinema species (X. brevicolle, X. elongatum, X. ifacolum and X. longicaudatum) and X. diffusum that is taxonomically very similar to X. brevicolle. Each species-specifi c reverse primer was located in the ITS-1 rDNA region and was used in combination with a universal forward primer located in the 18S rDNA gene. Primer reliability was confi rmed by screening seven and 11 populations, respectively of X. diffusum and X. elongatum. Potential speciesspecifi c primers were also identifi ed for X. brevicolle, X. longicaudatum and X. ifacolum, however too few populations of these species were available to thoroughly assess their reliability. For all speciesspecifi c primers, specifi city was demonstrated by the absence of cross-reactions with 14 non-target Xiphinema species. Multiplex PCR was effective and reproducible for two (X. longicaudatum and X. ifacolum) or three (X. brevicolle, X. diffusum and X. elongatum) of the target nematode species, thus improving the applicability of the diagnostic primers.

Comparative cytogenetic analysis of eleven species of subfamilies Neoplecostominae and Hypostominae (Siluriformes: Loricariidae).

Abstract: The family Loricariidae with about 690 species divided into six subfamilies, is one of the world's largest fish families. Recent studies have shown the existence of several problems in the definition of natural groups in the family, which has made the characterization of the subfamilies and even of some genera quite difficult. With the main objective of contributing for a better understanding of the relationships between loricariids, cytogenetic analysis were conducted with two species of Neoplecostominae and nine species of Hypostominae that, according to morphological and molecular data, may belong to a new monophyletic unit. The results obtained showed a marked chromosomal conservation with the presence of 2n = 54 chromosomes and single interstitial Ag-NORs in all species analyzed. Considering that Neoplecostominae is the primitive sister-group of all other loricariids, with exception of Lithogeneinae, this karyotypic structure may represent the primitive condition for the family Loricariidae. The cytogenetic characteristics partaken by the species of Neoplecostominae and Hypostominae analyzed in the present study reinforce the hypothesis that the species of both these subfamilies might belong to a natural group.

Comparative study of total lipids in beef using chlorinated solvent and low-toxicity solvent methods

Abstract: Nine extraction methods (three using chlorinated and six nonchlorinated solvents) were compared for determining lipids in samples of low-( 20%) ground beef. The nine methods investigated were: Folch, Lees, and Sloane Stanley (FLS); Bligh and Dyer (BD); Bligh and Dyer modified by Undeland, Harrod, and Lingnert (BDU); Bligh and Dyer modified by Smedes (BDS); Hara and Radin (HR); Schmid, Bondzynski, and Ratzalaff (SBR); Roese-Gottlieb (RG); Burton, Webb, and Ingold (BWI); and Soxhlet (SE). The BDS and HR methods do not include solvents such as chloroform and methanol and can be recommended for meat samples that have both low and high fat content. If the use of organic solvents is not critical, the FLS and the BD extraction methods yield the highest results, but the FLS is more expensive owing to the high amount of solvent required. Without considering the toxicity of the solvents, the three BD extraction methods provided the best yields.

Surprising genomic diversity in the Neotropical fish Synbranchus marmoratus (Teleostei: Synbranchidae): how many species?

Abstract: Summary of the available karyotypical data for Synbranchus marmoratus . Locations of the samples taken by river,municipality and state in Brazil (BR) and Argentina (AR), location codes employed in the present study, diploid numbers (2n),karyotypes and nuclear DNA content. SP= State of Sao Paulo; PR= State of Parana; MS= State of Mato Grosso do Sul; MT=State of Mato Grosso; GO = State of Goias; CE= State of Ceara; M = metacentric; SM = submetacentric; ST = subtelocentric;A = acrocentric; pg = picogram (10 -12 g). Locality Code 2n Karyotype Nuclear DNA content (pg)References Coxim, MS, BR 42 4M,SM+38ST,A Foresti et al . (1992) Sao Simao, GO, BR 42 4M,SM+38ST,A Foresti et al . (1992) Nova Granada, SP, BR 42 4M,SM+38ST,A Foresti et al . (1992) Botucatu, SP, BR 42 4M,SM+38ST,A Melillo et al . (1996) Birigui, SP, BR 42 4M,SM+38ST,A Melillo et al . (1996) Paraguacu Paulista, SP, BR 42 4M,SM+38ST,A Melillo et al . (1996) Pirassununga, SP, BR 42 6M,SM+36ST,A Melillo

Spermatozoa ultrastructure in Sciaenidae and Polynemidae (Teleostei:Perciformes) with some consideration on Percoidei spermatozoa ultrastructure.

Abstract: Spermatozoa ultrastructure was studied in five marines (Paralonchurus brasiliensis, Larimus breviceps, Cynoscion striatus, Micropogonias furnieri, Menticirrhus americanus, Umbrina coroides, Stellifer rastrifer), and one freshwater (Plagioscion squamosissimus) species of Sciaenidae and one species of Polynemidae (Polydactylus virginicus). The investigation revealed that, in all species, spermatozoa display a round head, a nucleus containing highly condensed, filamentous chromatin clusters, no acrosome, a short midpiece with a short cytoplasmic channel, and a flagellum showing the classic axoneme structure (9 + 2) and short irregular lateral fins. In Sciaenidae, the spermatozoa are type II, the flagellar axis is parallel to the nucleus, the lateral nuclear fossa is double arched, the centriolar complex is outside the nuclear fossa, the proximal centriole is anterior and perpendicular to the distal centriole, and no more than ten spherical (marine species) or elongate (freshwater species) mitochondria are observed. Polynemidae spermatozoa are of the intermediate type with the flagellar axis eccentric to the hemi-arc-shaped nucleus, and exhibit no nuclear fossa, the centriolar complex close to the upper nuclear end, the proximal centriole lateral and oblique to the distal centriole, and one large ring-shaped mitocondrion. The data available show that no characteristic is exclusively found in the spermatozoa of members of the Sciaenidae family when compared to other Percoidei with type II spermatozoa. However, three characteristics were exclusively found in Polynemidae: (1) the hemi-arched nucleus; the positioning of the centrioles; and (2) the ring-shaped mitocondrion. The interrelationships between Sciaenidae and Polynemidae as well as between these two families and other Percoidei are herein discussed.

Isolation and characterization of a satellite DNA family in Achirus lineatus (Teleostei: Pleuronectiformes: Achiridae).

Abstract: Agarose gels stained with Ethidium bromide and Southern blot experiments of HindIII-digested genomic DNA of Achirus lineatus evidenced the presence of monomers and multimers of a DNA segment of about 200 bp, named here Al-HindIII sequence. No signals were observed in Southern blot experiments with genomic DNA of other flatfish species. The DNA sequencing of four recombinant clones showed that Al-HindIII sequences had 204 bp and were 63.72% AT-rich. FISH experiments using a Al-HindIII sequence as probe showed bright signals in the centromeric position of all chromosomes of A. lineatus.

Comparative description and discussion of spermiogenesis and spermatozoal ultrastructure in some species of Heptapteridae and Pseudopimelodidae (Teleostei: Siluriformes)

Abstract: Os dados obtidos no presente estudo sobre a ultraestrutura da espermiogenese e dos espermatozoides de Pseudopimelodidae e Heptapteridae mostram que eles compartilham algumas caracteristicas, mas sao bastante diferentes uns dos outros. As principais diferencas sao a ocorrencia de espermiogenese do tipo I em Pseudopimelodidae e do tipo III em Heptapteridae, a presenca de fossa nuclear em Pseudopimelodidae e sua ausencia em Heptapteridae, a presenca de uma peca intermediaria longa em Pseudopimelodidae e uma peca intermediaria curta em Heptapteridae, a presenca de um canal citoplasmatico em Pseudopimelodidae e sua ausencia em Heptapteridae, a presenca de muitas vesiculas grandes na peca intermediaria de Pseudopimelodidae, e a presenca de vesiculas muito alongadas e dispostas em posicao periferica distal em Heptapteridae e mitocondrias distribuidas em toda a peca intermediaria de Pseudopimelodidae e muito proximas ao nucleo em Heptapteridae. Heptapteridae e Pimelodidae compartilham varias caracteristicas como a espermiogenese do tipo III, o mesmo padrao de condensacao da cromatina e a ausencia de fossa nuclear e projecoes laterais ou fins. O espermatozoide de Pseudopimelodidae e mais similar aos dos Siluridae, porem a ausencia de dados adicionais sobre a espermiogenese e o espermatozoide de outros siluriformes ainda limitam uma discussao mais ampla na ordem.

Comparative cytogenetics of nine species of Hypoptopomatinae (Teleostei: Siluriformes: Loricariidae): the importance of structural rearrangements in chromosome evolution

Abstract: Fishes of the subfamily Hypoptopomatinae are very common and found in the lowlands of cis-Andean South America from Venezuela to the north of Argentina. With the main objective of contributing for a better un- derstanding of the importance of chromosome rearrangements in the loricariid evolution, cytogenetic analyses were conducted in nine species of Hypoptopomatinae. The results showed a marked gross karyotypic conservation with the presence of 2n=54 chromosomes in all species analyzed. The main differences were found in the karyotypic for- mulae level. Most species had a single interstitial Ag-NORs, however terminal Ag-NORs were observed in three spe- cies. One species exhibited two Ag-NOR-bearing chromosome pairs. The distribution of C-band positive segments was species specific but chromosome markers were observed among the species analyzed. The gross cytogenetic characteristics observed among the Hypoptopomatinae species are similar to those observed in other primitive Lori- cariidae species suggesting that small changes, mainly paracentric and pericentric inversion were the main events in the karyotypic evolution of this fish group.

Chromosome Banding and 18S rDNA in situ Hybridization Analysis of Seven Species of the Family Achiridae (Teleostei: Pleuronectiformes)

Abstract: Achiridae is an important family of the order Pleuronectiformes widely distributed in North, Central, and South America with freshwater and marine species. In the present study cytogenetic analyses comprising conventional and molecular techniques were carried out in seven species of this family. The following diploid numbers (2n) and fundamental numbers (FN) were obtained: Achirus declivis 2n = 34, FN = 52; Achirus lineatus 2n = 40, FN = 66; Catathyridium jenynsi 2n = 40 and FN = 50; Gymnachirus nudus 2n = 36 and FN = 50; Hypoclinemus mentalis 2n = 38 and FN = 54; Trinectes paulistanus 2n = 42 and FN = 52; and Trinectes sp. 2n = 38 and FN = 54. All species presented a single nucleolar organizer region (NOR) bearing chromosome pair and C-band positive segments mainly distributed at the pericentromeric position. The wide variation observed in chromosome number and FN suggests the occurrence of larger chromosome rearrangements in the family Achiridae if compared with other families of the same order.

Comparative cytogenetic studies in species of the subfamily Callichthyinae (Teleostei: Siluriformes: Callichthyidae)

Abstract: — In the present study, the karyotype of three species (nine populations) of the Callichthyinae subfamily were investigated with the objective of better understanding the pattern of relationship among the genera that compose the subfamily. Among the four populations of Callichthys callichthys studied, two showed 2n = 56 chromosomes and two 2n = 58 chromosomes. Up to eight additional microchromosomes were observed in the sample from Marilia. The three populations of Hoplosternum littorale displayed the same number of chromosomes, 2n = 60, and karyotypic constitution, 6M + 2SM + 52A. The two populations of Megalechis personata showed 2n = 62 chromosomes and similar karyotypic formulae, 8M + 54A and 6M + 2SM + 54A. Terminal Ag-NORs were found in one chromosome pair of C. callichthys, H. littorale, and M. personata from Itiquira, and in two pairs in M. personata from Rio Branco. The populations of C. callichthys showed C-band positive segments in centromeric and pericentromeric position and the popul...

First chromosome Characterization in the Neotropical Eel, Gymnothorax ocellatus (Pisces, Muraenidae)

Abstract: Departamento Ciencias Biologicas Faculdade de Ciencias Campus de Bauru, 17033-360, Bauru, SP

Revision of the genus Pseudotocinclus (Siluriformes: Loricariidae: Hypoptopomatinae), with descriptions of two new species

Abstract: The genus Pseudotocinclus is revised and two new species are described: Pseudotocinclus juquiae from the Ribeira de Iguape basin and Pseudotocinclus parahybae from the rio Paraiba do Sul basin. The presence of a small naked area on the snout tip distinguishes P. tietensis from P. parahybae and P. juquiae, which have the snout tip covered with small platelets. In addition, P. tietensis has four transverse dark-brown bands on the dorsum coalesced with the midlateral stripe instead of three, as in its congeners. Pseudotocinclus juquiae is distinguished from its congeners by having the orbital ring very prominent and conspicuous, a characteristic not found in P. tietensis or P. parahybae. These three species also differ from their congeners by meristic and morphometric data. Comments on the past connection of Ribeira de Iguape, Paraiba do Sul and upper Tiete basins are presented.

Resistência de genótipos de cafeeiros a Pratylenchus coffeae e Meloidogyne incognita

Abstract: The lesion nematode Pratylenchus coffeae is one of the major parasites of coffee plants, making it an economically important agricultural pest. Despite the importance of coffee to the Brazilian economy there is a paucity of studies on P. coffeae in Brazil. Greenhouse experiments were established to investigate the comparative effect of P. coffeae isolate K 5 and Meloidogyne incognita race 2 on five coffee genotypes (Coffea canephora 'Robusta IAC 4804' and 'IAC 4810'; C. canephora 'Konillou IAC 4764' and 'IAC 4765'; and C. arabica 'Mundo Novo IAC 388-17') in terms of both plant growth and nematode reproduction (FR). Approximately seven months after plant inoculation, populations of both nematode species increased (FR > 1) and the fresh root weight of C. arabica 'Mundo Novo' was reduced. Determination of resistance/susceptibility of C. canephora 'Robusta IAC 4804' was inconclusive for M. incognita due to considerable variability in FR (0.1-32.6): however for P. coffeae this genotype was rated as susceptible. 'Robusta IAC 4810' was susceptible to P. coffeae but resistant to M. incognita. Also, both genotypes of C. canephora 'Konillou' were resistant to the K 5 isolate of P. coffeae but susceptible to Meloidogyne incognita race 2.

Rivulus hartii (Boulenger 1890) (Cyprinodontiformes: Rivulidae): especie de pez dulceacuícola amenazada en la isla de Margarita, Venezuela

Abstract: Margarita es una isla de 1.701 k m 2 de superficie y esta localizada en el Noreste de Venezuela entre las coordenadas 10° 51 50" - 11° 11 06 " latitud norte y 63o 40 40" - 64o 24 32" longitud oeste. El Ministerio del Ambiente de Venezuela, en su Atlas del Estado Nueva Esparta (MARNR 199 4), describe las condiciones climaticas del territorio insular, indicando que la mayoria de los cursos de agua naturales existentes, permanecen secos durante la mayor parte del ano, exceptuando el periodo de lluvias. Las unicas corrientes que permanecen a ctivas, al menos en la porcion superior de sus cuencas son los rios La Asuncion, El Valle, San Juan, Cupeicillo de Tacarigua y La Aguada de Pedro Gonzalez, los cuales tienen su origen en las partes altas de las montanas del Copey y Matasiete, debido a la frondosa vegetacion que reduce la excesiva evaporacion y contribuye a la condensacion de la humedad ambienta