RESUMO
A first genetic linkage map of the Atlantic cod (Gadus morhua) was produced, based on segregation data from 12 full-sib families of Norwegian origin. The map contained 174 single nucleotide polymorphism markers and 33 microsatellites, distributed on 25 linkage groups and had a length of 1225 cM. A significant difference in recombination rates between sexes was found, the average ratio of female:male recombination rates being 1.78 +/- 1.62 (SD).
Assuntos
Mapeamento Cromossômico , Gadus morhua/genética , Animais , Feminino , Masculino , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Recombinação GenéticaRESUMO
Eleven bacterial strains were isolated from the gastrointestinal tract of four fish species, Atlantic salmon (Salmo salar L.), Arctic charr (Salvelinus alpinus L.), Atlantic cod (Gadus morhua L.) and wolffish (Anarhichas lupus L.). All the strains were Gram-positive rods, non-sporing, catalase and oxidase-negative, able to grow at pH 9.0 but not on acetate containing media (pH < or = 5.4), and were fermentative. They had a high content of oleic acid (18:1 n-9) in cellular lipid, and were found to belong to the genus Carnobacterium by phenotypic criteria. The eleven carnobacteria strains were further identified on the basis of 16S rDNA sequence analysis and AFLP(TM) fingerprinting.
Assuntos
Peixes/microbiologia , Intestinos/microbiologia , Lactobacillaceae/classificação , Aeromonas/crescimento & desenvolvimento , Aeromonas/patogenicidade , Animais , Antibiose , Sequência de Bases , Metabolismo dos Carboidratos , DNA Bacteriano/análise , DNA Bacteriano/genética , DNA Ribossômico/análise , DNA Ribossômico/genética , Ácidos Graxos/análise , Lactobacillaceae/genética , Lactobacillaceae/crescimento & desenvolvimento , Lactobacillaceae/isolamento & purificação , Lactobacillaceae/ultraestrutura , Dados de Sequência Molecular , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Salmo salar/microbiologia , Alinhamento de Sequência , Análise de Sequência de DNA , Truta/microbiologiaRESUMO
The present study reports the effect of excessive handling stress and starvation on the lactic acid bacteria associated with the digestive tract of Atlantic salmon (Salmo salar L.). A relatively low population level (approximately 2 x 103 bacteria per gram wet tissue) of viable adherent heterotrophic bacteria was associated with the digestive tract (foregut, midgut and hindgut). Of the 752 bacterial isolates isolated from diet, water and the digestive tract, 201 isolates belonged to the carnobacteria. Of these isolates, one from the diet, one from the rearing water and 80 from the gastrointestinal tract, were further identified on the basis of 16S rDNA sequence analysis. All these isolates were identified as being Carnobacterium piscicola-like. Daily repeated stress and starvation of the fish over 11 d had no influence on the total culturable bacterial numbers or population level of C. piscicola associated with the digestive tract. C. piscicola-like isolates colonizing the various intestinal regions (foregut, midgut and hindgut) were also screened for their ability to produce growth inhibitory compounds active against the fish pathogen Aeromonas salmonicida. Of the 199 C. piscicola isolates tested, 139 inhibited growth of the pathogen.
