Papel de las actividades superóxido dismutasa y catalasa en la ...

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INTRODUCTION 2.2. VIRULENCE MECHANISMS Several virulence mechanisms have been described in P. damselae subsp. piscicida that include production of extracellular products (ECPs) with haemolytic, phospholipase and cytotoxic activities (Balebona et al., 1992; Magariños et al., 1992; Noya et al., 1995a and b; Romalde, 2002; Bakopoulos et al., 2004). In addition, virulent strains constitutively synthesize a thin layer of capsular material that confers resistance to serum killing and decreases macrophage phagocytosis (Magariños et al., 1996b; Arijo et al., 1998; Acosta et al., 2006). A close relationship has been observed between capsule production and iron availability. Thus, do Vale et al. (2001) observed that cells grown under iron-limiting conditions always have significantly lower amounts of capsular material. This thinner capsule probably results in a better exposure of the adhesins and iron receptors at the bacterial surface during passage through circulatory system. Once the microorganism reaches the different host tissues, the amount of capsular material probably increases in response to host cellular defence mechanisms such as phagocytosis 3. SUPEROXIDE DISMUTASE AND CATALASE ACTIVITIES AS VIRULENCE FACTORS Bacterial inactivation within phagocytes takes place by two mechanisms: oxygen independent mechanisms through phagocyte granule constituents (lysosomal enzymes, catepsines, defensines, lactoferrine, proteolytic enzymes) and oxygen dependent mechanisms. In the latter mechanisms oxygenic compounds such as hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2·- ) and hydroxyl radical (OH - ) takes place. These products are generated during the called respiratory burst, due to the activation after phagocytosis of nicotinamide-adenin-dinucleotide-phosphate-hydrogen (NADPH) oxidase located in the membranes. 74
INTRODUCTION 3.1. RESPIRATORY BURST After phagocytosis, a process that involves the ingestion of microorganisms, phagocytic cells liberate the content of their lysosomes and a phago-lysosome is formed. Lysosomes contain several cytotoxic factors, such as oxygen metabolites and hydrolytic enzymes capable to kill and digest microorganisms. Production of these oxygen metabolites occurs during the respiratory burst, within phagocytes in the presence of bacteria, increasing oxygen rate consumption. Extracellular oxygen is used to generate reactive oxygen species (ROS), O 2·- , H 2 O 2 , OH - in the cellular surface. The presence of these free radicals is associated with cellular ageing; however, their toxicity is useful as a defence mechanism against bacteria, due to their great microbiocidal activity. The respiratory burst starts by stimulation of the NADPH oxidase located in the phagocytic membrane. This enzymatic activity is able to reduce O 2 in superoxide anion (O 2·- ) (Roos et al., 2003). Sequentially, by univalent reduction of O 2 , highly toxigenic reactive species, are generated. Within the phagosome, superoxide is, spontaneously or by superoxide dismutase (SOD), converted to hydrogen peroxide (H 2 O 2 ), which may then react with superoxide to generate hydroxyl radicals (OH - ) and singlet oxygen ( 1 O 2 ), both highly reactive and toxic compounds. Superoxide can also react with nitrogen oxide (NO), generated by inducible NO synthase (NOS), to yield peroxynitrite, a very reactive nitrogen intermediate. There are even indications that single oxygen may be converted to a ozone-like (O 3 ) compound in a reaction catalyzed by antibodies bound to microbes or neutrophils. H 2 O 2 may also, together with chloride, be used as a substrate by myeloperoxidase released from granules to generate hypochlorous acid, a very toxic compound for almost all microbes. Subsequently, the short-lived hypochlorous acid can react with secondary amines to form secondary chloramines, which are as microbiocidal as hypochlorous acid but more stable. The respiratory burst, due to the generation of a great amount of free radicals highly toxic, inactivating proteins and oxidizing nucleic acids and other essential molecules, represents an immune system strategy in the fight against infections. Pathogenic microorganisms have had to develop a fight against free radicals, in two 75
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FACULTAD DE CIENCIAS DEPARTAMENTO D
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FACULTAD DE CIENCIAS DEPARTAMENTO D
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Los ensayos que constituyen esta Te
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- Díaz-Rosales, P, Arijo, S, Chabr
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Sabe esperar, aguarda que la marea
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ÍNDICE / INDEX Papel de las activi
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ÍNDICE / INDEX 2. Photobacterium d
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RESUMEN Photobacterium damselae sub
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INTRODUCCIÓN 1. LA ACUICULTURA. EL
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INTRODUCCIÓN saxatilis) (Hawke et
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INTRODUCCIÓN 2.2. SINTOMATOLOGÍA
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INTRODUCCIÓN las epidemias surgida
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INTRODUCCIÓN et al., 1997). En P.
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INTRODUCCIÓN 3.1. ESTALLIDO RESPIR
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INTRODUCCIÓN radicales generados e
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INTRODUCCIÓN Tabla 2 Ejemplos de m
Page 45 and 46: INTRODUCCIÓN de parasitismo en el
Page 47 and 48: INTRODUCCIÓN razón de la búsqued
Page 49 and 50: INTRODUCCIÓN araquidónico, están
Page 51 and 52: INTRODUCCIÓN simplificar la admini
Page 53 and 54: INTRODUCCIÓN sino también cuando
Page 55: INTRODUCCIÓN La necesidad de mejor
Page 59: OBJETIVOS El trabajo planteado en e
Page 63: MATERIA L Y MÉTODOS La metodologí
Page 67 and 68: RESULTADO S Y DISCUSIÓN El primer
Page 69 and 70: RESULTADO S Y DISCUSIÓN 1996; Lync
Page 71 and 72: RESULTADO S Y DISCUSIÓN Una vez de
Page 73 and 74: RESULTADO S Y DISCUSIÓN inmunoesti
Page 75 and 76: RESULTADO S Y DISCUSIÓN cruentum s
Page 77 and 78: RESULTADO S Y DISCUSIÓN permiten c
Page 79: RESULTADO S Y DISCUSIÓN harían fa
Page 83 and 84: CONCLUSIONES Tras los estudios real
Page 85: FACULTAD DE CIENCIAS DEPARTAMENTO D
Page 89: ABSTRACT Photobacterium damselae su
Page 93 and 94: INTRODUCTION 1. AQUACULTURE. THE CU
Page 95: INTRODUCTION With regard to Solea s
Page 99 and 100: INTRODUCTION Some catalases have al
Page 101 and 102: INTRODUCTION pathogens, study of th
Page 103 and 104: INTRODUCTION increase their bacteri
Page 105 and 106: INTRODUCTION 4.3.1. Porphyridium cr
Page 107 and 108: INTRODUCTION Different mechanisms h
Page 109: A I M S
Page 113: M A T E R I A L S A N D M E T H O D
Page 117: R E S U L T S A N D D I S C U S S I
Page 120 and 121: RESULTS AND DISCUSSION resist 100 m
Page 122 and 123: RESULTS AND DISCUSSION present work
Page 124 and 125: RESULTS AND DISCUSSION reason, once
Page 126 and 127: RESULTS AND DISCUSSION great number
Page 128 and 129: RESULTS AND DISCUSSION dominant spe
Page 131 and 132: CONCLUSIONS Studies carried out on
Page 133: R R E F E R E N C I A S E F E R E N
Page 136 and 137: REFERENCIAS / REFEREN CES Aoki, T,
Page 138 and 139: REFERENCIAS / REFEREN CES Bell, MV,
Page 140 and 141: REFERENCIAS / REFEREN CES Dalmo, RA
Page 142 and 143: REFERENCIAS / REFEREN CES Hamaguchi
Page 144 and 145: REFERENCIAS / REFEREN CES Kono, Y &
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REFERENCIAS / REFEREN CES Magariño
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REFERENCIAS / REFEREN CES Ortuño,
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REFERENCIAS / REFEREN CES Salinas,
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REFERENCIAS / REFEREN CES Thompson,
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S E C C I Ó N D E A R T Í C U L O
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A RTÍCULO 1.1. A RTICLE 1.1.
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Journal of Fish Diseases 2003, 26,
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A RTÍCULO 2.1. A RTICLE 2.1.
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Abstract The stimulatory effect of
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alga Porphyridium cruentum. For thi
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Feeding assays were carried out wit
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(10 8 bacterias ml -1 ) and used to
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are in agreement with the data repo
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unvaccinated fish. However, the ser
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immune response of gilthead seabrea
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[27] Duncan, PL and Klesius, PH. Ef
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(Macrogard) and alginic acid (Ergos
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[66] Salinas, I, Díaz-Rosales, P,
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Figure 1a 3 2.5 Stimulation index 2
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Figure 1c Stimulation index 3 2.5 2
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Figure 2b Stimulation index 3 2.5 2
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Effect of the extracellular polysac
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1. Introduction Solea senegalensis
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On the other hand, β-1,3-glucan fr
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eaction was tested by adding supero
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Intraperitoneal inoculation of the
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defense mechanisms and protective i
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phagocytes from sole (Solea senegal
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Figure 1a Stimulation index 3 2.5 2
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Figure 2 Stimulation index 1.4 1.2
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Effect of dietary administration of
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1. Introduction Senegalese sole cul
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2.2. Fish and experimental design S
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2.5. Challenge with Photobacterium
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the densitometric curves of the pro
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most efficient probiotics for aquac
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acterial diversity only the dominan
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[9] Verschuere, L, Rombaut, G, Sorg
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[28] Burr, G, Gathin, D and Ricke,
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WB, editors. Techniques in Fish Imm
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and host-specific communities of ac
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Table 1 Primer Sequence (5’-3’)
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Figure 1b Stimulation index 2.5 2 1
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Table 2 Primer Control Pdp11 Pdp13
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Figure 3 Pearson correlation [0.0%-
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que perdieras parte de tu tiempo en
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