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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 19 (1998), S. 197-203 
    ISSN: 1573-5168
    Schlagwort(e): epidermal cathepsins ; Japanese eel ; Anguilla japonica ; proteolytic activity ; bacteriolytic activity ; hemolytic activity ; immune response ; primary defence ; thermal adaptation ; bacterial infection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nonspecific responses of Japanese eels to environmental stress were monitored by assaying various lytic activities in eel epidermal extract. In fish maintained at 10 and 30 °C for up to 10 days, epidermal proteolytic activities due to serine protease and aminopeptidase and hemolytic activity varied within a 2-fold value range. Other proteolytic activities, due to cathepsins B and L, in the fish at 30 °C increased for up to 8 days and were 3.4 and 2.9-fold over those in fish maintained at 10 °C, respectively. This was accompanied by a 3.0-fold increase in bacteriolytic activity. Other forms of stress were exerted on the fishes by immersing them in a suspension of Flavobacterium columnare or giving them intraperitoneal injections of Edwardsiella tarda over 72 h. Although serine protease and aminopeptidase activities and hemolytic activity in the fishes exposed to F. columnare changed marginally, and were similar to those in the control fish, cathepsins B and L activities in the infected fishes increased more than 1.5-fold over their initial values over a 48 h period, along with a 4.5-fold increase in bacteriolytic activity. No marked change was detected in any of the lytic activities of the fishes exposed to E. tarda. These findings indicate that epidermal cathepsins B and L probably participate in bacteriolysis associated with Japanese eel skin and that their activities are elicited by environmental stimuli and may be an important nonspecific response of eels. Abbreviations: Cbz – carbobenzoxy; MCA – 4-methylcoumaryl-7-amide.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 19 (1998), S. 205-209 
    ISSN: 1573-5168
    Schlagwort(e): direct activity detection ; epidermal cathepsins ; fluorescence microscopy ; histochemical localization ; Japanese eel ; primary defense ; secretory cells ; skin ; Anguilla japonica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Histochemical localization of proteolytic activities in the dorsal epidermis of Japanese eel was demonstrated by fluorescent microscopy utilizing 4-methoxy-2-naphthylamide (4M$\beta$NA) derivatives as substrates and 5-nitrosalicylaldehyde as a trapping agent. Carbobenzoxy-L-phenylalanyl-L-arginyl-4M$\beta$NA (Cbz-Phe-Arg-4M$\beta$NA) and Cbz-Arg-Arg-4M$\beta$NA were used for direct detection of cathepsins L and B activities, respectively, in fresh frozen sections and unfixed cells of the eel epidermis. The fluorescing areas, where Cbz-Phe-Arg-4M$\beta$NA was hydrolyzed by cathepsin L, were shown in mucus secretory cells and club cells and broadly around skin surface. The fluorescing areas due to Cbz-Arg-Arg-4M$\beta$NA hydrolysis by cathepsin B were localized similarly in these tissues. The fluorescing intensity for both catheptic activities in mucus secretory cells was higher than that in club cells, where small fluorescing granules were distributed. These results indicate that eel cathepsins L and B are stored in epidermal secretory cells at different levels and probably serve as defense factors before or after secretion by these cells. Abbreviations: Cbz – carbobenzoxy; 4M$\beta$NA – 4-methoxy-2-naphthylamide; NSA – 5-nitrosalicylaldehyde.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 20 (1999), S. 37-41 
    ISSN: 1573-5168
    Schlagwort(e): Anguilla japonica ; bacterial diseases ; bacteriolysis ; epidermal cathepsins ; Japanese eel nonspecific defense ; pathogenic bacteria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cysteine proteases, cathepsins L and B, in Japanese eel epidermis are suspected bacteriolysins against aquatic pathogens. This work examines the lysis of three species of gram-negative pathogenic bacteria by the eel epidermal extract according to the assay method for cysteine proteases. The optimum pH for the lysis of the three species of bacteria were commonly determined to be 5.0, where both of eel epidermal cathepsins L and B caused active proteolysis. Four kinds of specific inhibitors for cysteine proteases strongly inhibited these catheptic proteolyses and bacteriolyses. The activities for the lysis of three types of bacteria were at a similar level, but the effects on the bacterium which infects predominantly eel skin largely varied with individual fish. These results suggest that epidermal cathepsins L and B are responsible for lysis of any pathogenic bacteria in the nonspecific defense of Japanese eel.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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