Protein Toksininsektisidal Dari Bakteri Patogen Serangga Photorhabdus Luminescens Hj [Insecticidal Toxin Protein Produced by Enthomopathogenic Bacterium Photorhabdus Luminescens Hj]

Photorhabdus luminescens HJ is an entomopathogenic bacterium that has a high toxicity against Tenebrio molitor larvae.Toxicity assay of crude extra cellular protein precipitated using ammonium sulphate showed that the highest toxin activity was found in 70 % saturation. Purification of the toxin using Hi Prep 16/60 Sephacryl S-200 HR column exhibited one fraction of toxic protein and three fractions of non-toxic protein. Mortality of T. molitor larvae treated with 19.2 nanogram of toxic fraction was up to 80%. Denatured protein analysis using sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that the toxic fraction was composed of three proteins, which were 19.5, 42, and 66 kDa respectively. Based on toxin activity bioassay, this toxin type was an injectable toxin and presumably classified as Mcf toxin

Produksi Dan Evaluasi Antibodi Poliklonal Untuk Deteksi Toksin Photorhabdus Spp.

Production and Evaluation of Polyclonal Antibody forDetection of Photorhabdus spp. Toxin. Yadi Suryadi, IfaManzila, Alina Akhdiya, and Etty Pratiwi. The researchwas aimed to produce and evaluate polyclonal antibody(PAb) for specific Photorhabdus spp. bacterial toxin detection.Photorhabdus spp. toxin of HJ isolates which was purifiedusing Hi Prep. 16/60 Sephacryl S-200 HR column chromatographyrevealed three different peaks of polypeptides.The results showed that the protein concentration of crudeantigen protein (supernatant) was 3,711 μg/μl, whilst fractionof protein was 1,95 x 10-2 μg/μl, respectively. The bioassayusing Tenebrio molitor larvae-3 indicated that after 48 happlication, the percentage of larvae mortality by crude antigenwas lower (73%) than by fraction antigen (93%). Basedupon NCM-ELISA test, PAb of fraction protein derived fromHJ isolate reacted with Photorhabdus spp. antigen yieldedstronger or darker violet color on membrane than that ofcrude protein. In addition, it was observed that PAb coulddifferentiate specifically Photorhabdus spp. toxin with otherbacterial filtrate such as Xanthomonas oryzae pv oryzae, X.campestris pv glycinea, Ralstonia solanacearum, Pseudomonassyringae pv glycinea and P. fluorescens, however itshowed cross reaction with Escherichia coli. Further testsare needed in optimizing PAb-Photorhabdus spp. sensitivityto achieve effective concentration for detection of Photorhabdusspp. toxin as well as specificity test against otherbacterial antigens