caa a22 4500 465822851 CHVBK 20180323112140.0 cr unu---uuuuu 170327e19901001xx s 000 0 eng 10.1007/BF00170920 doi (NATIONALLICENCE)springer-10.1007/BF00170920 Partial inactivation of the mosquitocidal activity of Clostridium bifermentans serovar malaysia by extracellular proteinases [Elektronische Daten] [Luc Nicolas, Sylviane Hamon, Emmanuel Frachon, Madeleine Sebald, Huguette de Barjac] Summary: Clostridium bifermentans serovar malaysia is toxic to mosquito larvae. During large-scale preparation in a fermentor, the bacteria enter the sporulation stage after 5 h culture, whereupon high larvicidal activity is obtained (LC50 48 h on Anopheles stephensi = 3.1 × 10−5). The toxicity becomes maximal around 3-5 h later (LC50 48 h = 1.3 × 10−5) and remains unchanged until sporangium lysis. An important loss of toxicity is then observed when the cells lyse. This loss appears to be due to the fact that C. bifermentans serovar malaysia synthesizes and excretes, mainly during vegetative growth, metallo- and/or cystein-proteinases, which are active between pH 6.0 and pH 8.0. Extracellular proteinases are most likely responsible in large part for the decrease in toxic activity concomitant with cell lysis. Lysis is however prevented by addition of 10 mM ethylenediaminetetraacetic acid to the culture medium before forespore formation, and under these conditions the larvicidal activity can be maximized. Springer-Verlag, 1990 Nicolas Luc Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut Hamon Sylviane Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut Frachon Emmanuel Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut Sebald Madeleine Unité des Anaérobies, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut de Barjac Huguette Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut Applied Microbiology and Biotechnology Springer-Verlag 34/1(1990-10-01), 36-41 0175-7598 34:1<36 1990 34 253 https://doi.org/10.1007/BF00170920 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00170920 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nicolas Luc Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut NATIONALLICENCE 700 1- Hamon Sylviane Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut NATIONALLICENCE 700 1- Frachon Emmanuel Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut NATIONALLICENCE 700 1- Sebald Madeleine Unité des Anaérobies, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut NATIONALLICENCE 700 1- de Barjac Huguette Unité des Bactéries Entomopathogènes, Institut Pasteur, 25 rue du Dr Roux, F-75724, Paris cedex 15, France aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer-Verlag 34/1(1990-10-01), 36-41 0175-7598 34:1<36 1990 34 253 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer