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Abstract SUMMARY The main aim of the present study is to evaluate chitosan nanoparticles as a carrier of DNA through transformation E. coli, plant cells, and plant single nodes. Two different molecular weights chitosan samples were used as DNA carrier for transformation. Viscometry method was used to determine sample molecular weights. Sample (A) was 501 KDa, located in medium molecular weight chitosan range, while sample (B) was 827.9 KDa located in high molecular weight chitosan range. Titration method was used to determine the degree of deacetylation (DDA). Sample (A) DDA was 66.26% and Sample (B) was 76.95%. Chitosan /DNA complex sizes determined by transmission electron microscopy were 109, 125 n.m. for chitosan samples A and B, respectively. Chitosan /DNA complex formation, and protection effect from anionic surfactant was examined by agarose gel electrophoresis proved that chitosan nanoparticals can protect DNA molecule in gene delivery. Chitosan effect was determined in both E. coli and plant cells. Effect of chitosan on E. coli leads to reduced bacterial population as the concentration increases. Sample (A) higher lethal effect on competent cells 55.11% than its effect on normal cells 47.6% in the lowest concentration, and 99.98%, 97.37% for the highest one, respectively. The obtained results indicate that sample (A) had higher lethal effect sample (B) in E.coli normal cells 43.5% in lowest concentration and 94.4% for the highest one. In case of competent cells lowest concentration was led to 54.29%, and the highest was 99.4%. For plant cells, chitosan sample (B) 54.24% had higher lethal effect than sample (A) 47.37% in their highest concentration, and 42.98%, 37.03% in the lowest concentration, respectively. The transformation efficiency of bacteria by incubated nanoparticles including plasmid DNA was examined by colony forming unit (CFU) on Luria-Bertani (LB) + ampicillin plates. The transformation 47 Nour-El-Hoda M. Sorour (2017), Ms.C, Fac. Agric., Ain Shams Univ. efficiency of chitosan DNA complex in case of normal cells was (1.53E+07, 1.08E+08, 5.61E+08, 3.50E+09) for type (A) with chitosan concentration in complexes was more efficient than type (B) (2.83E+07, 1.09E+08, 3.93E+08, 2.14E+09) transformation efficiency gradually increased chitosan with concentration in complexes. The transformation efficiency of bacterial competent cells in the same manner of normal cells (5.35E+07, 3.40E+08, 3.75E+09, 7.20E+11) for chitosan type (A) and (7.00E+07, 2.29E+08, 1.03E+09 2.53E+10) for type (B) while control transformation was 4.48E+08. The effect of different vortex times on frequency of plant cell transformation was studied. The transformation percentage of plant cell was determined by detecting green fluorescent protein (GFP) expression using fluorescent microscope. Without vortex, sample (A) was gave (4.81%, 16.72%, 22.73%, 32.24%), while sample (B) gave (9.57%, 10.95%, 6.48%, 14.57%) gradually with increased chitosan concentration in chitosan DNA complex. In case of 30 Sec. vortex, transformation percentage for sample (A) were (8.16%, 10.34%, 24.09%, 29.30%), and for sample (B) were (10.52%, 10.32%, 5.49%, 9.36%). The percentage was achieved by 60 Sec. vortex, sample (A) was gave (9.62%, 13.93%, 17.05%, and 21.11%), sample (B) (7.09%. 6.08%, 4.32%, 8.83%). Transformation of Plant single nodes that determined by green fluorescent protein (GFP) expression under U.V. light was obviously succeed for both types of chitosan |