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Author Manasherob, Robert ♦ Ben-Dov, Eitan ♦ Zaritsky, Arieh ♦ Barak, Ze’ev
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Protozoan Tetrahymena Pyriformis ♦ Bacillus Thuringiensis Subsp ♦ Excreted Food Vacuole ♦ Food Vacuole ♦ Thuringiensis Subsp ♦ Electron Microscopy ♦ Pyriformis Cell ♦ New Possible Mode ♦ Israelensis-killed Larva ♦ Many Human Infectious Disease ♦ Larvicidal Activity ♦ Spore Multiplication Value ♦ Outgrown Cell ♦ Bacterium Bacillus Thuringiensis Subsp ♦ Vegetative Growth ♦ Insecticidal Crystal Protein ♦ Various Time ♦ Nontarget Organism ♦ Undigested Material ♦ Toxic Crystal ♦ Viable-cell Counting
Abstract Spores of Bacillus thuringiensis subsp. israelensis and their toxic crystals are bioencapsulated in the protozoan Tetrahymena pyriformis, in which the toxin remains stable. Each T. pyriformis cell concentrates the spores and crystals in its food vacuoles, thus delivering them to mosquito larvae, which rapidly die. Vacuoles containing undigested material are later excreted from the cells. The fate of spores and toxin inside the food vacuoles was determined at various times after excretion by phase-contrast and electron microscopy as well as by viable-cell counting. Excreted food vacuoles gradually aggregated, and vegetative growth of B. thuringiensis subsp. is-raelensis was observed after 7 h as filaments that stemmed from the aggregates. The outgrown cells sporulated between 27 and 42 h. The spore multiplication values in this system are low compared to those obtained in carcasses of B. thuringiensis subsp. israelensis-killed larvae and pupae, but this bioencapsulation represents a new possible mode of B. thuringiensis subsp. israelensis recycling in nontarget organisms. The bacterium Bacillus thuringiensis subsp. israelensis (12, 15, 27) is used worldwide to control mosquitoes and blackflies, vectors of many human infectious diseases (for example, see reference 29). Its larvicidal activity is caused by insecticidal crystal proteins (ICP) that are produced during sporulation
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Publisher Date 1997-01-01