Iranian Journal of Biotechnology
Year:2006 | Volume:4 | Issue:2|Papers Count:10

The biosynthetic pathways of saturated and unsaturated fatty acids consist of many steps controlled by various enzymes. One of the methods for improving oil quality is to change the fatty acid profile through genetic manipulation which requires isolation and characterization of the genes and other cis-acting elements, such as the promoter, involved in fatty acid biosynthesis. β-ketoacyl-CoA synthase (KCS) that is the key enzyme in erucic acid biosynthesis. This enzyme is involved in producing eicosanoeic (C20:1) and erucic acids (C22:1) from C18 fatty acids, and is encoded by the fatty acid elongase (FAE) gene. Specific primers were used to amplify the FAE gene and its promoter from genomic DNA by using PCR technique. The putative gene and its promoter were cloned in sense and antisense orientation into the plant expression vector (pBI121). The sense and antisense constructs of the FAE gene were transformed via Agrobacterium-mediated transformation into low erucic acid rapeseed (LEAR such as PF) and high erucic acid cultivars (HEAR such as Maplus). The transformed plants were screened on kanamycin-containing media and then analysed by PCR and Southern blotting techniques. Moreover, erucic acid content of the first generation of transgenic (T0) plants analysed with gas chromatography, showed significant changes in fatty acid composition of transgenic rapeseed plants containing sense and antisense constructs of the FAE gene.

To identify quantitative trait loci (QTLs) controlling heading date and plant height, ninety nine F13 recombinant inbred lines (RILs) derived from barley cultivars Azumamugi × Kanto Nakate Gold cross were evaluated. The field trails were conducted at randomized complete block design with two and three replications in 2004 and 2005, respectively. Significant differences and transgrassive segregates were observed among lines for heading date and plant height. Composite interval mapping (CIM) was done based on linkage map constructed using 99 RILs and 100 markers including isozyme, morphological, STS and AFLP markers. A strong QTL controlling 26% phenotypic variation of heading date on chromosome 5HL was located near to the e07m25.3-e 12m199.1 markers. The QTL had the same interval of the Sgh2 locus. Allele inherited from Azumamugi parent in this locus decreased heading date. The QTL for heading date in the map interval of ABC261-ABG055 markers on chromosome 1HL could be identical with the eam8 locus and accounted for 11% of the phenotypic variation.New QTL for plant height was detected near to uzu1 locus on chromosome 3HL, explaining 52% of the phenotypic variation. The effect of allele transmitted from Azumamugi parent in this locus decreased plant height. The QTLs identified on chromosomes 1HL, 3HL and 7HS in relation to eam8, uzu1 and dsp1 genes showed pleiotropic effects on controlling heading date and plant height.

The cDNA from the mycoparasitic fungus Trichoderma atroviride PTCC5220 encoding a 42 kDa chitinase (Chit42) was isolated. The nucleotide sequence of the cDNA fragment as having a 1263 bp open reading frame that encodes a 421 amino acid polypeptide, and a high homology was found with other reported Chit42 belonging to the Trichoderma sp. The 22 amino acid N-terminal sequence is a putative signal peptide for the possible secretion of the protein. The protein has been expressed and secreted as a mature form in Escherichia coli BL21 (DE3) using the pelB leader sequence. The E. coli strain expressed Chit42 in an active form and secreted the protein into the medium. This recombinant chitinase has been shown to have inhibitory activity on mycelial growth and also, lytic activity on the cell wall of Rhizoctonia solani (AG2-2), causal agent of root rot in sugar beet in vitro. Expressed chitinase was optimally active at pH 5 and at 40°C. It is thermally stable at 60°C for more than 120 min at pH 5.

With the aim of the production of human factor VIII antigen and its corresponding antibody an epitope coding fragment of the light-chain of hFVIII, fused to a His6-tag, was isolated and over-expressed in Escherichia coli. The over-expressed hFVIII-epitope containing peptide was confirmed by its reaction with a rabbit serum directed against native hFVIII as well as antiHis6-tag antibody. An expression level of 6.5 mg/l (of culture) of the C1C2-related peptide was estimated. The purified product was used to develop antibody in rabbit. The immunoblotting experiment confirmed that the rabbit polyclonal antibodies developed against the purified bacterially expressed hFVIII sub-fragment, recognizes human plasma derived FVIII. Both the produced hFVIII-related antigen and its corresponding antibody are useful in experiments using for detection and purification of hFVIII as well as the clinical diagnosis of hFVIII related disorders.

The effect of p53 gene therapy on chemosensitivity and apoptotic response of PANC-1 tumor cells, which express high amount of mutant p53, to cancer chemotherapeutic agents of Etoposide and Doxorubicin was investigated.Comparison of the chemosensitivity of PANC-1 cells to its wild type p53 transfectants showed that wt-p53 expressing transfectants are more sensitive to both Etoposide and Doxorubucin. It further showed that neither the PANC1 cells nor its wild type p53 transfectants arrested at G1 in response to X-irradiation. Furthermore, treatment of both PANC-1 cells as well as its wt-p53 transfectants with etoposide resulted in apoptosis despite the difference in their p53 status, although, the number of apoptotic cells of the wt-p53 transfectants was higher compared to the control cells. This evidence reinforce the view that combining p53 gene therapy with conventional chemotherapeutic agents may yield a more beneficial response than conventional treatments alone in pancreatic tumor cells with high amount of mutant p53.

Genotypes for melatonin receptor type 1A (MTNR1A) and Calpastatin (CAST) were determined by enzymatic digestion of PCR products and Calpain (CAPN) genotype detected by PCR-SSCP method in Iranian Karakul sheep. Blood samples were collected from 100 purebred Karakul sheep. The extraction of genomic DNA was based on guanidinium thiocyanate- silica gel method. PCR amplicons were digested with restriction enzymes Mnll and MspI for MTNR1A and CAST genes, respectively. The MTNR1A locus had two alleles with frequencies of 0.79 for (+) and 0.21 for (-) alleles. Allelic frequencies for CAST locus were 0.85 for M and 0.15 for N. In addition, Calpain had two alleles A and B with respective frequencies of 0.79 and 0.21. The observed heterozygosity values for MTNR1A, Calpastatin and Calpain locus were 0.42, 0.29 and 0.35, respectively. The X2 test confirmed the existence of Hardy-Weinberg equilibrium for the three loci in the population. The data showed a large variation in studied genes. The genetic polymorphism could be regarded as useful tool for selection programs based on marker- assisted selection between different genotypes of those loci.

Modeling and simulation of Polyhydroxybutyrate (PHB) production by Protomonas extorquens in fed-batch culture were conducted in this research. The fed-batch model, developed for this process, employed a kinetic model proposed by other researchers. Several kinetic models were investigated to choose the best model. The criterion for this selection was goodness of fit d2. Haldane kinetic model was selected since it leads to the lowest d2. Experimental data that have been used in this study were extracted from literature. The kinetic model was then incorporated into the process model. The values of process model parameters were estimated by employing an optimization routine developed in this study and using two sets of experimental data. These data were obtained applying two different methods of fed-batch cultivation. The values of d2 for these two methods were 2.5 and 0.0016 respectively. Finally, simulation results were compared with two other sets of experimental data to validate the model.

Biotechnology offers a variety of potential environmental, social and economic benefits but, it is the center of extreme public and political debate at present. A major field of discussion in biotechnology is genetically modified (GM) organisms. New medical, political, ethical and religious discussions arise over the production and consumption of these organisms. Many surveys have been conducted in industrialized countries to investigate the public perceptions regarding the risks and benefits of biotechnology, while in developing countries hardly any studies have been done so far. The present descriptive study intends to contribute to a better understanding of public attitudes toward biotechnology and GM foods in Iran. To assess the public’s knowledge and opinions on the dangers or opportunities of genetic modification, 300 university students as a sample of educated community and 300 individuals with no university’s education as a sample of ordinary people were asked to complete a specially designed questionnaire on the risks and benefits of biotechnology and GM foods. This article summarizes the current situation with regard to biotechnology, with a particular focus on GM foods and discusses the results of the survey. Our results indicated that public’s knowledge about biotechnology is low in Iran and more efforts are needed to improve their understanding of different aspects of biotechnology.

The inhibitory effects of essential oils including clove, lavender and geranium extracted from Eugenia caryophyllata, Lavandula officinal is and Pelargonium graveolens on multidrug resistant isolates of Pseudomonas aeruginosa were investigated. The main constituents of clove, lavander and geranium oil were eugenol (80-90%), 1,8-cineol (13%) and citronellol (45%) respectively. Clove had the most effective essential oil against P. aeruginosa. A combination consisting of clove, lavender and geranium oils at a ratio of 3:1:1 showed the most inhibitory effect (32-64 mg/ml) and strong synergy with gentamicin. The essential oils from clove, lavender and geranium exhibited bactericidal activity against multi-drug resistant strains of P. aeruginosa and may be alternatives compounds against these strains in the future.

Thank you for your efforts in the dissemination of science and technology in our country. Also many thanks to the authors of the article “Association of apolipoprotein E polymorphism with susceptibility to multiple sclerosis” (Hadavi et al., 2004) for their valuable study. In that article, the frequency of apolipoprotein E (apoE) E2/E3 genotype and that of the apoE2 allele in control group have been reported respectively as 66.7% and approximately 48%, while the maximum reported frequency of apoE2 allele in the world is about 12% and the most frequent allele in all populations is apoE3 (Mahley and Rall, 2000).