1. Effects of associated bacteria on the pathogenicity and reproduction of the insect-parasitic nematode Rhabditis blumi (Nematoda: Rhabditida).
- Author
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Park HW, Kim YO, Ha JS, Youn SH, Kim HH, Bilgrami AL, and Shin CS
- Subjects
- Animals, Bacteria isolation & purification, Bacteria pathogenicity, Coleoptera microbiology, Coleoptera parasitology, Flavobacterium growth & development, Flavobacterium isolation & purification, Insecta microbiology, Larva microbiology, Larva physiology, Lepidoptera microbiology, Lepidoptera parasitology, Providencia growth & development, Providencia isolation & purification, Reproduction physiology, Rhabditoidea microbiology, Rhabditoidea physiology, Symbiosis, Bacteria growth & development, Insecta parasitology, Rhabditoidea pathogenicity
- Abstract
Three bacteria, Alcaligenes faecalis , Flavobacterium sp., and Providencia vermicola , were isolated from dauer juveniles of Rhabditis blumi . The pathogenic effects of the bacteria against 4th instar larvae of Galleria mellonella were investigated. Providencia vermicola and Flavobacterium sp. showed 100% mortality at 48 h after haemocoelic injection, whereas A. faecalis showed less than 30% mortality. Dauer juveniles showed 100% mortality against G. mellonella larvae, whereas axenic juveniles, which do not harbor associated bacteria, exhibited little mortality. All of the associated bacteria were used as a food source for nematode growth, and nematode yield differed with bacterial species. Among the bacterial species, P. vermicola was most valued for nematode yield, showing the highest yield of 5.2 × 10(4) nematodes/mL in the plate. In bacterial cocultures using two of the three associated bacteria, one kind stimulated the other. The highest total bacterial yield of 12.6 g/L was obtained when the inoculum ratio of P. vermicola to A. faecalis was 10:1. In air-lift bioreactors, the nematode growth rate increased with an increasing level of dissolved oxygen. The maximum nematode yield of 1.75 × 10(5) nematodes/mL was obtained at 192 h with an aeration rate of 6 vvm.
- Published
- 2011
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