MODERN GENETICS JOURNAL (MGJ)
Year:2007 | Volume:2 | Issue:1|Papers Count:8

Insect pests constitute a major constraint in crop production and approximately 15% of agricultural production is lost by insect pests every year. Bt crops inherent resistance to insect pests represent an important tool in integrated pest management (IPM). These plants in addition to effective control of insect pests, have benefits and potential impacts in agriculture including increased yields, reduced pesticide use, less environmental damages, increased farmer incomes and reduced labors. The area under Bt crops have increased to more than 70 million hectars in 2005. Safety of Bt crops have confirmed by world organizations such as World Health Organization (WHO). In the Bt crops' stability of insect pest resistance and effective control is important. Several strategies have been developed for insect resistance management (IRM), including high dose/active refuge. However, development and introduction of new approaches in future is required to ensure permanent potential impacts and certain benefits of Bt transgenic plants in modem agriculture.

To study components of partial resistance toward maganapOr the grisea Hebert. fungus in some rice cultivars Tarom mahalli, Nemat, San Huang Zhan-2, C101-PKT and C104-PKT, were tested in greenhouse experiments and in an upland nursery experiment in Amol Rice Research Institute in 2002. The experiment was conducted in the diallel desing in a Randomized Complete Block Design (RCBD) with three replications. Traits in this study were infection type (IT), lesion number (LN), lesion size (LS, mm2), percent diseased leaf area (DLA, or disease severity percent) and sporulation capacity (SC, spore/gram fresh weight). Results showed that the cultivars and F1 differenced significantly. Tarom mahalli and hybrid combination (Tarom mahalli/ Nemat) showed susceptible reaction. For these traits, Nemat, San Huang Zhan-2 and hybrid combinations of these cultivars with the other cultivars were resistant to the three fungus strains (IA-90, IA-89, IA-82) in greenhouse and field races of blast. Using the area under disease progress curves as a measure of relative disease progress in the nursery disease development on Nemat, San Huang Zhan-2 and hybrid combinations (F1) of these cultivars with the other cultivars were slight, Tarom mahalli and hybrid combination (Tarom mahalli/ Nemat) were high. Hayman analysis showed the high additive gene effect were observed in controlling DLA to the fungus strains (IA-89,IA-90) and LS to the fungus strains (IA-89, IA-82) and SL to the fungus strains (IA-89).These results indicate the main effect of genetic elements on plant resistance to blast diseases.

One of the most important diseases of alfalfa is the wilt disease caused by Fusarium spp. and Verticillium albo atrum). Using resistant varieties is the best and low costing way for control plant diseases, therefore producing of alfalfa resistance varieties against Fusarium spp. has economical importance. The main objectives of this experiment were to obtain the healthy initial material for producing alfalfa resistance varieties. Regarding the above objective, the seeds of four varieties with Iranian and foreign provenance including: (variety No. 328 from Turkish country, variety Nikshari No. 11 from Iran, variety Ranger No. 219 from America and Simerchenskia No. 17 from Ghazaghestan) were cultivated in specially boxes, after 6 week, the seedlings of those varieties were inoculated with two concentrations of spores 30×104/ml and 20×104/ml for F. solani and 60×104/ml and 45×104/ml for F.oxsporum. Inoculated seedlings of each variety with 4 treatments of two species of fungi and 1 treatment without inoculation (control) were studied in random complete design in greenhouse condition. The mean disease severity index of varieties in response of two species was calculated on the basis of symptoms on the samples of plants and on cross section of their roots. According to the value of mean diseases severity index of each variety, 3 varieties with foreign provenance were got as degree of 2 by standard method, and therefore they considered as medium resistance varieties. Iranian variety with degree of less than 1 was considered as resistant variety.

Astaxanthin is a xanthophylls, a fat-soluble, oxygenated pigment a member of the carotenoid family. It has a unique molecular structure that 500 times-gives it powerful antioxidant function. Astaxanthin has 100 the antioxidant capacity of Vitamin E and 10 times the antioxidant capacity of beta-carotene and also stronger antioxidant than lutein, lycopene and tocotrienols. Mutagenesis of Phaffia rhodozyma was done with different concentrations of NTG. After many times of selections, mutated colonies were obtained that were resistant to 0.05% 2-Deoxyglucose. These were tested in GPY broth for astaxanthin formation. Four mutant’s colonies obtained with 250mg/ml of NTG. The highly pigmented mutants produced approximately 485 mg of total carotenoid per g yeast estimated as astraxanthin, compared with the parental strain which had 250 mg/g. The results of TLC analysis of carotenoid composition of P. rhodozyma mutant indicated that mutant strain produced five different carotenoids on the basis of polarity and RF values.

Development of bacterial databases is crucial and every year the number of prokaryotic genome is increasing. The problem of identifying genes in genomic DNA sequences by computational methods has attracted considerable research attention in recent years.A Full automatic and self-train Gene finder is presented in this research. This system uses non-looped HMM to measure of statistical significance for Genes in prokaryotic genomes. Design of this software was done in three main programs and developed in C++. First program is presented for extraction the DATA (Long non-overlapping ORFs) to train the machine learning algorithm in a self-training method. Second program is related to the training stage. In this stage, HMM is trained with the data that obtained in the previous stage. We model standard 'text book genes' with an unbroken open reading frame. In the last program, The Long ORFs is scored with the trained system. Finally, Genes are selected on the base on their lengths and scores. Our Gene finder can predicts genes with Specifity >96 and Sensetivity>84. The result shows that overall performance of our software matches other methods that are designed by others.

Prostate cancer has been known as the second leading cause of death in men. Different methods are employed in prostate cancer treatment, including surgery, radiotherapy, hormone therapy, and chemotherapy. The application of each of these treatments depends upon the clinical stage but none of them increase survival effectively. Gene therapy is suggested as a valuable method in cancers including prostate cancer.Insulin-like growth factors (IGFs) are known as strong mitogens. Recent studies have shown that IGFs particularly the type I insulin-like growth factor (IGF-IR) play an important role in the regulation of tumor growth. Inhibition of IGF-IR signaling by using antibody or antisense against IGF-IR could inhibit the growth and plating efficiency of some cancer cells in vivo and in vitro. It has been demonstrated that some of the human prostate cancer cell lines, especially DU-145, overexpress IGF-IR. In the present study, we have used the antisense strategy to reduce the IGF-IR expression in DU-145 cells. For this purpose, DU-145 cells were transfected with the antisense IGF-IR expression vector and the level of IGF-IR mRNA and protein was measured by using RTPCR and immunoblotting. The RT-PCR and immunoblotting results show the significant reduction in mRNA and protein of IGF-IR as compared with DU-145 transfected cells with control vector and untransfected DU-145 cells.

Direct micro injection of recombinant gene is a regular technique for genetic alteration in mouse. In this study our aim was to optimize micro injection and also factors effecting the technique in mouse zygote. For this study, we prepared various sizes of micro injecting needles. Fertilized zygotes were harvested from super ovulated mouse treated with PMSG and hCG. Then, cDNA molecules of human growth hormone gene were injected into male pronuclus of mouse zygote and allowed to develop into 2 - 4 cell embryo. Zona plucida were desolved, polymerase chain reaction were performed with specific primers for human growth hormone gene and also B-actin as a control, we also studied the response of different strains of mice to hormonal treatment and also effect of various diameter size of injecting needle on cell division of zygotes. Results indicated that type of needle, strains of mouse and also hormonal dose could affect the technique. However 90% of zygotes obtained from F1 (NMRI X BALB/c) mouse after DNA micro injection could proceed to 2 cell embryo in DMEM/F12 culture media. Also, KSOM medium ceases arrest at 2 - cell stage of embryo.