Abstract A new species of Myxobolus parasitizing the arterial bulb and cardiac musculature of the freshwater fish Pimelodus ornatus Kner, 1858, from the Arari river in the municipality of Cachoeira do Arari, island of Marajó, Pará, Brazil, was described. In the present study, the observed prevalence of myxozoan parasites in the heart tissue of the hosts was 20% (6/30). The myxozoans observed had mature biconvex spores, slightly rounded, an anterior end with two pyriform polar capsules and a posterior end with very evident sporoplasm, measuring 8 ± 0.2 μmin length. The spore width was 5.8 ± 0.4 μm, with a thickness of 3.4 ± 0.2μm. The length of the polar capsules was 3.6 ± 0.3 μm and the width was 1.2 ± 0.2μm, with 6 to 7 turns of the polar filament. The divergences observed, regarding the morphometric and genetic structure of SSU rDNA, in relation to other Myxobolidae already described in the literature, confirm the description of the new species Myxobolus rangeli n. sp.

Resumo Descrição de uma nova espécie de Myxobolus que parasita o bulbo arterial e a musculatura cardíaca do peixe de água doce Pimelodus ornatus Kner, 1858, do rio Arari, no município de Cachoeira do Arari, ilha de Marajó, Pará, Brasil. No presente estudo, a prevalência observada de parasitas mixozoários no tecido cardíaco dos hospedeiros foi de 20% (6/30). Os mixozoários observados apresentavam esporos maduros biconvexos, levemente arredondados, extremidade anterior com duas cápsulas polares piriformes e extremidade posterior com esporoplasma bem evidente, medindo 8 ± 0,2 μm de comprimento. A largura do esporo foi de 5,8 ± 0,4 μm, com espessura de 3,4 ± 0,2 μm. O comprimento das cápsulas polares foi de 3,6 ± 0,3 μm e a largura foi de 1,2 ± 0,2 μm, com 6 a 7 voltas do filamento polar. As divergências observadas, quanto à estrutura morfométrica e genética de SSU rDNA, em relação a outros Myxobolidae já descritos na literatura, confirmam a descrição da nova espécie Myxobolus rangeli n. sp.

Abstract The characteristics of milk are controlled by several genes, with emphasis on the four genes from casein, CSN1S1; CSN1S2; CSN2 and CSN3, which are responsible encoding of fractions the milk protein. The study of genetic variants in these genes, seek to investigate alleles, insertions or deletions, that can directly reflect on productive characteristics, indicating differences in milk quality, composition and yield. The CSN1S1 and CSN3 genes were analyzed in lactating Murrah buffaloes using nucleotide sequencing. An SNP was found in the amplified fragment of the CSN1S1 gene, located in nucleotide number 2,123 of the promoter region in position nt-258 (A/G). As for the CSN3 gene, two SNPs of exon number 4 were identified in codons 33 (ACC/ATC) and 34 (ACC/ACT) of the analyzed fragment. This study contributes to important associations between genetic variants and the desired characteristics of milk and its derivatives in future studies, because the variants found may be associated with the quality of milk, enabling genetic selection to be assisted by molecular markers, indicating a major advance that makes it possible to select animals early.

Resumo O presente estudo tem como objetivo descrever uma nova espécie de Sphaerospora encontrado na bexiga urinária de Mesonauta festivus, coletado no distrito Corre Água, no município de Macapá, estado do Amapá (Brasil). Foram realizadas análises morfométricas e filogenéticas, nas quais se avaliou a relação entre as espécies de mixosporídeos já descritas. A nova espécie possui plasmódio poliespórico, que varia em tamanho e forma. Os esporos maduros são subesféricos. Na visão sutural, apresentam 5,3 ± 0,2 (5,2-5,6) μm de comprimento e 7,0 ± 0,7 (6,3-7,7) μm de largura, com duas cápsulas polares piriformes de tamanhos iguais, 2,5 ± 0,2 (2,3-2,8) μm de comprimento e 1,8 ± 0,2 (1,6-2,0) μm de largura. As análises filogenéticas das sequências parciais do gene 18S rDNA confirmam ser uma nova espécie e determinou a relação desta com outros myxozoários já relatados. Conclui-se que a espécie em estudo pertence à família Sphaerosporidae, gênero Sphaerospora, e nova espécie, Sphaerospora festivus n. sp. e primeira ocorrência de parasitos desse gênero no Brasil.

Abstract The present study describes a new species of the genus Sphaerospora found in the urinary bladder of the flag cichlid, Mesonauta festivus collected in Corre Água district of the municipality of Macapá, Amapá State (Brazil). The study includes morphological and phylogenetic analyses of the new parasite, to determine the relationship of the new species with related myxosporean species. The new species has polysporous plasmodia, which vary in size and shape. The mature myxospores are subspherical shape in valvar view. In the sutural view, the myxospores are 5.3±0.2 (5.2-5.6) μm in length and 7.0±0.7 (6.3-7.7) μm in width, with two piriform polar capsules equal size, 2.5±0.2 (2.3-2.8) μm in length and 1.8±0.2 (1.6-2.0) μm in width. The phylogenetic analyses of a partial sequence of the 18S rRNA gene confirmed the status of the new species and determined the relationship of the new species and related myxosporean species.The sum of the evidence indicates that, Sphaerospora festivus n. sp. belongs to the family Sphaerosporidae, and is the first record of the genus Sphaerospora from Brazil.

Resumo Henneguya sacacaensis n. sp. é descrito em espécimes do Osteichthyes Satanoperca jurupari (Heckel, 1840), coletados na área de Proteção Ambiental do rio Curiaú na cidade de Macapá no estado do Amapá, Brasil. Com auxílio de microscopia óptica e análises moleculares, esses parasitos foram analisados e observados nas brânquias em forma de cistos, contendo centenas de esporos e apresentaram a prevalência de 57,14%. Os cistos encontrados nas lamelas branquiais tinham formatos ovais e esbranquiçados. Seus esporos apresentaram um comprimento médio de 46,5 (41,3-56,92) µm, corpo fusiforme medindo 16,5 (13,16-20,01) µm de comprimento e 5,1 (3,91-6,12) µm de largura, suas duas cápsulas polares apresentam uma conicidade de 3,83 (3,4-4,32) µm e sua largura 1,68 µm (1,4-1,99), a cauda 30 (22,47-41,67) µm de comprimento, contento um filamento polar de 7 à 9 voltas. Análises morfológicas e filogenéticas permitiram a preposição de uma nova espécie, Henneguya sacacaensis n. sp, que pertence à família Myxobolidae e ao gênero Henneguya.

Abstract This study describes Henneguya sacacaensis n. sp. in specimens of the Osteichthyes Satanoperca jurupari (Heckel, 1840), collected in the Rio Curiaú Environmental Protection Area in the city of Macapá, state of Amapá Brazil. Using optical microscopy and molecular analysis, these cyst-shaped parasites were analyzed. The gills of 57.14% of the analyzed S. jurupari contained hundreds of spores. The cysts found on the gill lamellae were oval-shaped and whitish. The Henneguya spores had an average length of 46.5 (41.3-56.92) µm. The fusiform body of the Henneguya measured 16.5 (13.16-20.01) µm long and 5.1 (3.91-6.12) µm in width, the two polar capsules had a taper of 3.83 (3.4-4.32) µm and a width of 1.68 (1.4-1.99) µm, and the tail measured 30 (22.47-41.67) µm in length, containing a polar filament coiled seven to nine times. Morphogical and phylogenetic analysis allowed the preposition of a new species, Henneguya sacacaensis n. sp, that belongs to the family Myxobolidae and the genus Henneguya.

Resumo O objetivo deste estudo foi descrever a infecção por Kudoa orbicularis em Trachelyopterus galeatus. Foram analisados 80 espécimes de T. galeatus capturados no município de Cachoeira do Arari, ilha de Marajó, estado do Pará, Brasil. A presença de pseudocistos nas fibras musculares das regiões epiaxial e hipoaxial em 85,0% dos exemplares analisados, mostra alto grau de infecção. Os pseudocistos continham esporos de formato pseudoquadrado, medindo 4,65 (4,04-5,54) µm de comprimento e 5,25 (4,78-5,98) µm de largura, com quatro cápsulas polares de tamanho iguais medindo 2,22 (2,05-2,32) µm de comprimento e 1,53 (1,56-1,74) µm de largura. Através das análises morfológicas dos esporos e molecular de uma sequência parcial de 934bps do gene SSU rDNA, confirma que o microparasito é Kudoa orbicularis, sendo este o segundo registro desse microparasito em hospedeiro da ordem Siluriformes da Amazônia brasileira.

Abstract The aim of this was describe an infection by Kudoa orbicularis in freshwater catfish Trachelyopterus galeatus. A sample of 80 specimens of T. galeatus was collected in the municipality of Cachoeira do Arari, Marajó Island, in the state of Pará, Brazil. Pseudocysts were found in the muscle fibers of the epaxial and hypaxial regions of 85.0% of the specimens analyzed, reflecting a high infection rate. The pseudocysts contained spores that were pseudo-square in shape, with a mean length of 4.65 µm (range: 4.04–5.54) and mean width of 1.53 µm (1.56–1.74). Analyses on the morphology of the spores and a partial 934-bp sequence of the SSU rDNA gene confirmed that the microparasite was Kudoa orbicularis. This is the second record of this microparasite in a siluriform host in the Brazilian Amazon region.

ABSTRACT The present study evaluated the genetic variability of the broodstocks of tambaqui hatcheries in the Brazilian state of Pará. Samples were obtained from the caudal fin of 110 broodstocks from one hatchery in each of four municipalities (Santarém, Peixe-Boi, Breu-Branco, and Ulianópolis), representing all the individuals of each hatchery stock. The samples were genotyped using the multiplex system microsatellite markers. Data were used to calculate observed and expected heterozygosity, number of alleles per locus, and allelic richness. The effective population size and inbreeding coefficient were also calculated. The genetic differentiation between populations was evaluated by using FST, and population structuring by the most likely number of genetically homogenous populations and Unweighted Pair Group Method (UPGMA); the arithmetic means were based on Nei's. The indices indicated a loss of genetic variability in the broodstocks from Ulianópolis, Peixe-Boi, and Breu-Branco in comparison with wild tambaqui populations, although this was not apparent in the Santarém stock. A moderate level of genetic differentiation was found among the tambaqui broodstocks based on the FST estimates, which were reinforced by the structuring found in the Bayesian analysis and UPGMA. This reflects the domestication process, given that no such structuring is found in natural tambaqui populations. This moderate genetic differentiation associated with the loss of genetic variability found in the four tambaqui broodstocks from the state of Pará provides important insights for the development of future programs of genetic improvement, as well as the conservation of the genetic diversity of these stocks.

Resumo Este estudo fornece dados morfológicos e moleculares de um novo parasita encontrado na parede intestinal do jandiá, Rhamdia quelen coletado na região da ilha do Marajó (Estado do Pará, Brasil), um importante recurso pesqueiro com potencial para aquicultura. Foram realizadas comparações morfológicas deste parasita e análises filogenéticas da região do gene 18S rDNA sequenciada. Os esporos foram morfologicamente distintos das espécies de outros Myxobolus descritos anteriormente. A sequência parcial obtida do gene 18S rDNA da nova espécie foi comparada com outras 24 espécies de Myxobolus e Henneguya retiradas do GenBank. Os resultados de análises morfológica e molecular indicaram claramente a existência de uma nova espécie, Myxobolus marajoensis sp. n.

Abstract This study provides morphological and molecular data of a new parasite species found in the muscle layer of the intestinal tract of the South American silver catfish, Rhamdia quelen from Marajó Island region (Pará State, Brazil), an important fishery resource with recognized potential for fish farming. The morphology of these parasites was reanalyzed and phylogenetic analyses were run on their 18S rDNA gene sequences. The spores were morphologically distinct from those of other Myxobolus species described previously. The obtained partial sequence of the 18S rDNA gene sequences of the new species were compared to those of 24 other Myxobolus and Henneguya species available in GenBank. The results of morphological and molecular analyses indicated clearly the existence of a new species, Myxobolus marajoensis sp. n.

Abstract Colossoma macropomum is the second largest scaled fish of the Amazon. It is economically important for commercial fisheries and for aquaculture, but few studies have examined the diversity and genetic structure of natural populations of this species. The aim of this study was to investigate the levels of genetic variability and connectivity that exist between three natural populations of C. macropomum from the Amazon basin. In total, 247 samples were collected from the municipalities of Tefé, Manaus, and Santarém. The populations were genotyped using a panel of 12 multiplex microsatellite markers. The genetic diversity found in these populations was high and similar to other populations described in the literature. These populations showed a pattern of high gene flow associated with the lack of a genetic structure pattern, indicating that the number of migrants per generation and recent migration rates are high. The values of the FST, RST, and exact test of differentiation were not significant for pairwise comparisons between populations. The Bayesian population clustering analysis indicated a single population. Thus, the data provide evidence for high genetic diversity and high gene flow among C. macropomum populations in the investigated region of the Amazon basin. This information is important for programs aiming at the conservation of natural populations.

Different risk factors for venous thromboembolism (VTE) have been identified, including hereditary abnormalities in the mechanisms of coagulation and fibrinolysis. We investigated five genetic polymorphisms (FVL G1691A, FII G20210A, MTHFR C677T, TAFI A152G and TAFI T1053C) associated with VTE in individuals from the city of Belém in the Brazilian Amazon who had no history of VTE. No significant difference was found between the observed and expected genotype frequencies for the loci analyzed. We found high frequencies of MTHFR C677T (33.9%) and TAFI T1053C (74%) and low frequencies of FVL (1.6%), FII G20210A (0.8%) and TAFI A152G (0.8%). The FVL G1691A, FII G20210A and MTHFR C677T frequencies were similar to those for European populations and populations of European descent living in the city of Ribeirão Preto in the Brazilian state of São Paulo. The frequency of the two TAFI mutations in the Belém individuals was not significantly different from that described for individuals from Ribeirão Preto. We suggest that the risks for VTE in the population of Belém are of the same magnitude as that observed in European populations and in populations with an expressive European contribution.