ABSTRACT
Abstract Yellow pigmented, filamentous, Gram-negative bacteria belonging to genus Flavobacterium are commonly associated with infections in stressed fish. In this study, inter-species diversity of Flavobacterium was studied in apparently healthy freshwater farmed fishes. For this, ninety one yellow pigmented bacteria were isolated from skin and gill samples (n = 38) of three farmed fish species i.e. Labeo rohita, Catla catla and Cyprinus carpio. Among them, only twelve bacterial isolates (13.18%) were identified as Flavobacterium spp. on the basis of morphological, biochemical tests, partial 16S rDNA gene sequencing and phylogenetic analysis. On the basis of 16S rDNA gene sequencing, all the 12 isolates were 97.6-100% similar to six different formally described species of genus Flavobacterium. The 16S rDNA based phylogenetic analysis grouped these strains into six different clades. Of the 12 isolates, six strains (Fl9S1-6) grouped with F. suncheonense, two strains (Fl6I2, Fl6I3) with F. indicum and the rest four strains (Fl1A1, Fl2G1, Fl3H1 and Fl10T1) clustered with F. aquaticum, F. granuli, F. hercynium and F. terrae, respectively. None of these species except, F. hercynium were previously reported from fish. All the isolated Flavobacterium species possessed the ability of adhesion and biofilm formation to colonize the external surface of healthy fish. The present study is the first record of tropical freshwater farmed fishes as hosts to five environmentally associated species of the Flavobacterium.
Subject(s)
Animals/classification , Animals/genetics , Animals/isolation & purification , Animals/microbiology , Animals/physiology , Animals/veterinary , DNA, Bacterial/classification , DNA, Bacterial/genetics , DNA, Bacterial/isolation & purification , DNA, Bacterial/microbiology , DNA, Bacterial/physiology , DNA, Bacterial/veterinary , DNA, Ribosomal/classification , DNA, Ribosomal/genetics , DNA, Ribosomal/isolation & purification , DNA, Ribosomal/microbiology , DNA, Ribosomal/physiology , DNA, Ribosomal/veterinary , Fish Diseases/classification , Fish Diseases/genetics , Fish Diseases/isolation & purification , Fish Diseases/microbiology , Fish Diseases/physiology , Fish Diseases/veterinary , Fishes/classification , Fishes/genetics , Fishes/isolation & purification , Fishes/microbiology , Fishes/physiology , Fishes/veterinary , Flavobacteriaceae Infections/classification , Flavobacteriaceae Infections/genetics , Flavobacteriaceae Infections/isolation & purification , Flavobacteriaceae Infections/microbiology , Flavobacteriaceae Infections/physiology , Flavobacteriaceae Infections/veterinary , Flavobacterium/classification , Flavobacterium/genetics , Flavobacterium/isolation & purification , Flavobacterium/microbiology , Flavobacterium/physiology , Flavobacterium/veterinary , Fresh Water/classification , Fresh Water/genetics , Fresh Water/isolation & purification , Fresh Water/microbiology , Fresh Water/physiology , Fresh Water/veterinary , India/classification , India/genetics , India/isolation & purification , India/microbiology , India/physiology , India/veterinary , Molecular Sequence Data/classification , Molecular Sequence Data/genetics , Molecular Sequence Data/isolation & purification , Molecular Sequence Data/microbiology , Molecular Sequence Data/physiology , Molecular Sequence Data/veterinary , Phylogeny/classification , Phylogeny/genetics , Phylogeny/isolation & purification , Phylogeny/microbiology , Phylogeny/physiology , Phylogeny/veterinary , /classification , /genetics , /isolation & purification , /microbiology , /physiology , /veterinaryABSTRACT
O presente trabalho levanta questöes referentes à análise de diferentes aprendizagens no contexto da organizaçäo temporal do comportamento. A análise fundamenta-se em literatura sobre a ritmicidade endógena de todos os sistemas fisiológicos. Especificamente, a influência de ritmicidade circadiana na aquisiçäo e manutençäo de respostas condicionais e na modulaçäo comportamental é revista em estudos com diferentes espécies animais. Também säo abordadas pesquisas recentes sobre sincronizaçäo de ritmos circadianos à administraçäo de melatonina exógena, questionando o papel deste hormônio na organizaçäo circadiana em geral. No conjunto, tais evidências enfatizam o interesse em análises das relaçöes entre variaçäo circadiana da aprendizagem e níveis plasmáticos de melatonina como um possível meio para o entendimento da organizaçäo temporal da aprendizagem.
Subject(s)
Animals , Behavior , Learning , Periodicity , Animals/classification , MelatoninABSTRACT
El hombre, al igual que cualquier otro organismo, es parte de los ecosisitemas que forman la tierra. pero a diferencia de los otros, es el único ser que puede modificar estos ecosistemas en forma planificada, adaptando el medio ambiente vivo y no vivo a sus necesidades. El constante progreso tecnológico tiene como consecuencia la creciente independencia del hombre de las circunstancias cambiantes de su entorno, y ha permitido el aumento explosivo de la población humana en los dos últimos siglos.