Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2003.715.720Periplaneta amreicana]]>SerajU. M.HoqM. I.AnwarM. N.ChowdhuryS. 7200367Attempts were made to isolate, purify and characterize antibacterial peptides from the hemolymph of the American cockroach Periplaneta americana. Both non-induced and induced hemolymphs were tested for their antibacterial activity against several Gram-positive and Gram-negative bacteria. Induction was done by injecting Escherichia coli into the abdominal cavity of the cockroach. A time-induction study showed that antibacterial peptides were induced as early as 1/2 an hour with a peak at 9 h which started to decline around 24 h. The non-induced hemolymph showed activity only against E. coli whereas induced hemolymph showed activity against several Gram-positive and Gram-negative bacteria as well as against one antibiotic resistant E. coli. The induced hemolymph was subjected to SDS-PAGE to estimate the number and molecular weight of proteins present in the crude hemolymph. Seven distinct protein bands were detected by SDS-PAGE. The hemolymph was then subjected to gel filtration chromatography to purify the proteins responsible for the antibacterial activity. Twenty fractions, one ml each, were collected and all the fractions were tested against those bacteria which previously showed sensitivity to the crude hemolymph. Only six fractions were found to be effective against the tested bacteria. The protein concentrations in the active fractions were determined by spectrophotometry. The active fractions were finally subjected to SDS-PAGE to determine the molecular weight of the protein(s) which were responsible for the antibacterial activity. There was one protein in all these six fractions except fraction F13 where an additional protein of 67kDa was present. The approximate molecular weight of the isolated antibacterial protein present in all the fractions was 61kDa. It was found that only 2.87 μg of the protein could inhibit bacterial growth whereas approx.10 μg of conventional antibiotics was required to obtain similar result.]]>Asling, B., M. Dushay and D. Hultmark,1995Drosophila immune response by PCR-based differential display: The attacin A gene and the evolution of attacin-like proteins.]]>25511518Barra, D., M. Simmaco and H. Boman,1998430130134Boman, H.,1998481525Boman, H.G.,1995136192Casteels, P., C. Ampe, F. Jacobs and P. Tempst,1993Apis mellifera).]]>26870447054Charalambidis, N.D., L.C. Foukas and V.J. Marmaras,1996236200206Chowdhury, S., K. Taniai, S. Hara, K. Okuda and Y. Kato et al.,1995Bombyx mori.]]>214271278Cociancich, S., A. Ghazi, C. Hetru, J.A. Hoffmann and L. Letellier,1993Micrococcus luteus.]]>2681923919245Fehlbaum, P., P. Bulet, S. Chernysh, J.P. Briand and J.P. Roussel,19969312211225Gillespie, P.J., M.R. Kanost and T. Trenczek,199742611643Hara, S. and M. Yamakawa, 1995Bombyx mori.]]>2702992329927Hultmark, D.,1993Drosophila and other insects: A model for innate immunity.]]>9178183Hultmark, D., H. Steiner, T. Rasmuson and H.G. Boman,1980Hyalophora cecropia.]]>106716Jomori, T. and S. Natori,1992Periplaneta americana as an opsonin.]]>296283286Jomori, T., T. Kubo and S. Natori,1990Periplaneta americana.]]>190201206Juliet, M.R., J.R.S. Chisholm, G.D. Kemp and V.J. Smith,1999Carcinus maenas.]]>264350357Kyung, T.C. and D.D. Ourth,2000Heliothis virescens pupae.]]>267677683Laemmli, U.K.,1970227680685Matsuyama, K., S. Natori,1990Sarcophaga peregrina (flesh fly).]]>108201206Morishima, I., T. Horiba, M. Iketani, E. Nishioka and Y. Yamano,1995Bombyx mori.]]>19357363Okada, M. and S. Natori,1985Sarcophaga peregrina.]]>229453458Okada, M. and S. Natori,1984Sarcophaga peregrina (flesh fly) larvae.]]>222119124Thornqvist, P.O. and K. Soderhall,1997Powning, R.F. and W.J. Davidson,1973Galleria mellonella and Bombyx mori.]]>45669686Samakovlis, C.P., D.A. Kylsten, A. Kimbrell, Engstrom and D. Hultmark,1991Drosophila melanogaster.]]>10163169Saito, T., S. Kawabata, M. Hirata and S. Iwanaga,19952701449314499Taniai, K., K. Kadono-Okuda, Y. Kato, M. Yamamoto, M. Shimabukuro, S. Chowdhury and M. Yamakawa,1995Bombyx mori.]]>163215219Yamada, K. and S. Natori,1994Sarcophaga peregrina (flesh fly).]]>298623628Zasloff, M.,1992437Natori, S.,1994pp: 123-134pp: 123-134