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الكشف عن السمية الوراثية لمستخلصات نبات الحرمل Peganum harmala L . باستعمال بعض المؤشرات الخلوية والجزيئية == Detection of genetoxic effect of Peganum harmala L. extracts by using some molecular and cytogenetic markers
Author name:
سيف محمد ابراهيم
Supervisor name:
نضال نعمة حسين
General topic:
Biology
Specific topic:
Plant - Molecular Biology
Degree:
Master
University:
University of Baghdad
Language:
Arabic
University location:
Baghdad
First pages:
24T3342 - p.pdf
Abstract:
Evaluation of genetoxicity of the aqueous and alcoholic extracts of Peganum harmala L. seeds was assayed in onion roots Allium cepa as a biological system. Onion roots were subjected to different concentrations of aqueous and alcohol extracts (10,25,50,100,200%) V/ W for different periods( 24,48,72) hrs in order to study the effects of these extracts on onion′s root growth and some cytological properties included, (Mitotic index, phase index, proportion and types of chromosomal aberrations), as well as to assess the effect of these extracts on the DNA of onion roots using Random amplification polymorphic DNA (RAPD) technology.The results revealed that all harmala seeds extracts the aqueous and alcoholic caused a significant reduction of onion root growth, the reduction was positively proportional with the increasing concentrations of the extracts. The half maximal effective Concentration (EC50) against onion′s root growth was 50% in the case of using the aqueous extract while it reached 25% in the case of alcoholic extract. This result indicate the efficiency of the alcoholic extract over the aqueous extract on onion′s root growth.Results also showed that both harmala seeds extracts resulted in significant reduction of the mitotic index (MI) of onion′s roots tips compared with the control treatment .The reduction of the MI was also positively proportional with the increasing concentrations of the extracts .Although MI was not affected by the increase in duration of exposure .Therefore ,since the concentration 100% and 25% of the aqueous and alcoholic extracts respectively lowered the MI to nearly 50% compared to the control, they were considered sub lethal, whereas the concentration 200% of both extracts which caused a reduction of the MI to nearly 22% compared to control treatment was considered as lethal concentrations. The results showed a significant reduction prophase and significant increase of metaphase in onion′s root cells due to the treatments with both extracts. Moreover high percentages of chromosomal aberrations were alsodetected, and these aberrations were also positively associated with the increasing concentration and exposure periods. to The most frequent abnormalities were (Chromosomes stickiness, Chromosomal bridges , Chromosome disturbance and C - mitosis) .Moreover some other infrequent chromosomal abnormalities were also appeared such as ( Lagging chromosome ,Star anaphase, Shifting of poles, Polyploidy).The effect of both harmala seeds extracts was tested on DNA of onion′s roots using a random amplification polymorphic DNA (RAPD). Out of ten random primers used, seven were gave multiple bands for all studied, samples with molecular weights ranged between (90 - 1400) base pair .The results of random amplification showed that all harmala extract concentrations tested caused damage to DNA which mutations revealed as loss of a single or more band, or appearing of new bands. Additionally the total lost and gained band in samples treated with alcoholic extract reached 43 bands compared to the samples treated with the aqueous extract which revealed 35 bands , This result indicate the effectiveness of the alcoholic extract over the aqueous in it′s effect on DNA of onions roots. Furthermore, The results showed that the total number of the gained bands was more than that of the lost ones for both extracts with most primers used . The total numbers of the new bands in the samples treated with the aqueous extract were 27 bands whereas 32 bands , with alcoholic extract. However ,the total number of lost bands in samples treated with aqueous extract were 8 bands compared to 11 bands with alcoholic extract.The percentage of the genomic template stability (GTS% ) was lowered initially from the concentration 10% for both extracts ,this reduction was negatively associated with the increasing concentrations of the extracts, indicating the existence of great damage to the DNA with the increasing concentrations of the extract. The decrease of GTS in samples treated with alcoholic extract was more than that with the aqueous extract. A highest reduction 78.56% was detected at concentration 25 and 200 % in samplestreated with the aqueous extract, whereas a higher reduction 69.03% was recorded lower at concentration 50% in samples treated with alcoholic extract.Genetic dendrogram of samples treated with exposed to harmala seeds extracts in addition to the control using Jaccard coefficient of genetic variation and based on RAPD results showed segregation of onion samples treated with aqueous extract from samples treated with aqueous extract from samples treated with alcoholic extract, as well as segregation of the control treatment in a single group, this result confirms the great damages of onions root DNA when treated with harmala seed extracts..
