Bt Research 2015, Vol.6, No.7, 1-3
3
repeated twice. Bioassays were conducted at 28°C
2ºC and a 16: 8-h (light/dark) photoperiod. Absolute
mortality and functional mortality rates (dead larvae
plus larvae remaining in the first instar) were scored
after 7 days.
4 Notes
By developing the experimental procedure described
in this protocol, the Bt-like isolates can be preliminary
identified as
Bacillus thuringiensis
in 5 days of work,
from the isolation to the preliminary determination of
its toxic activity. However,
further studies such as PCR
amplification and sequencing of 16S rDNA, PCR
amplification (and sequencing) of insecticidal genes
commonly harboured by this bacterium (e.g.
cry
,
cyt
and
vip
), analysis of their SDS-PAGE protein profiles
and bioassays involving additional insect species
should be also performed in order to complement the
preliminary characterization of the isolated strains.
Acknowledgements
I thanks to the Consejo Nacional de Investigaciones
Científicas y Técnicas (CONICET), Argentina (post-
doctoral fellowship awarded to Dr. Leopoldo Palma). I
also thanks to Dr. Diego Sauka for kindly providing
HD1, HD133 and IPS82 Bt strains and to Alejandra
Lutz for her help in insect rearing and providing
larvae for preliminary bioassays. I thank to Dr.
Eleodoro del Valle for his assistance in soil sampling
and Dr. Laureano Frizzo for providing microbiological
resources for performing bacterial isolation.
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