فهرست مطالب

Biotechnology - Volume:4 Issue: 4, Autumn 2006

Iranian Journal of Biotechnology
Volume:4 Issue: 4, Autumn 2006

  • تاریخ انتشار: 1385/12/20
  • تعداد عناوین: 9
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  • Mohammad Sarrafzadeh, Fredric Bigey, Jean, Marie Navarro Page 217
    Recent technological improvements have extended the application range of dielectric permittivity biomass measurements to on-line monitoring of physiological changes during bacterial fermentations. In an industrial fermentation of Bacillus thuringiensis, it is important to verify the intactness of bacterial plasmid content in all steps of culture. Changes in certain plasmid resident properties of this bacterium affect the permittivity measurements and could represent the potential signs of change in the plasmid content. In order to study this, the permittivity measurements of cultures of two plasmid-containing (Cry+) and plasmid-free (Cry-) phenotype strains of B. thuringiensis H14 were followed and compared throughout the fermentation. They showed different profiles of permittivity during vegetative growth and sporulation phases which related to the inability of the Cry- phenotype strain to form aggregates and proteinaceous crystals, respectively. Cry- strain grew faster than Cry+ strain, but both of them were able to sporulate. The respiratory quotients of strains were similar during the growth phase but during sporulation phase the Cry- strain had a lower respiratory quotient than the Cry+ strain. Ke
  • Ali Hatef Salmanian, Kobra Zakikhan, Afsoon Afshari, Mandana Moshashaie, Mahyat Jafari, Amir Mousavi Page 224
    Site-directed mutagenesis (SDM) as a powerful technique was used to change two important and conserved amino acids in 5-enolpyruvylshikimate 3- phosphate synthase (EPSPS) gene of E. coli. The mutations changed glycine 96 to alanine and alanine 183 to threonine. These two amino acids are very important for intraction of the wide spectrum herbicide, glyphosate, to EPSP synthase enzymes. By designing mutagen primers and overlapping extension method, three kinds of altered bacterial EPSPS enzymes with first, second and both mutations were produced. These modified enzymes are expected to show decreased affinity for herbicide, with least alteration in their enzymatic activity. These altered genes were cloned under the control of chemically inducible T7 promoter and over expressed in E. coli. Biological activity analyses in the presence of glyphosate show that the bacteria containing the mutated enzymes, especially the enzyme with two mutations, were more tolerant to glyphosate.
  • Seyedeh Marjan Varedi Koolaee, Seyed Abbas Shojaosadati, Valliollah Babaeipour, Nasser Ghaemi Ghaemi Page 230
    The objective of this research was to investigate the influence of the over-expression of recombinant interferon-? during high cell density cultivation on cellular characteristics of recombinant E. coli. Batch and fed-batch culture techniques were employed to grow Escherichia coli BL21 for production of human gamma-interferon in pET expression system. Final cell densities in batch and fed-batch cultivations were approximately 7 and 127 g cell dry weight (CDW) l-1, respectively. In both systems, specific growth rate decreased and reached zero, 4 hours after the induction. It was found that high cell density and over-expression of interferon-? had no substantial effects on cell lysis and plasmid stability. Plasmid content of the cells was nearly similar and remained constant during the post-induction period in both batch and fed-batch cultures (60 mg plasmid per g-1 CDW). In both systems, time profiles of acetate and lactate production were similar, lactate concentration was lower than that of acetate and the concentrations of both were lower than the inhibitory level. Maximum extracellular cAMP concentration occurred at the start of induction in fed-batch culture and was higher than the amount produced during the batch process. The size of E. coli cells reduced significantly as cell density increased and the morphology of the cells in high cell density changed from the usual rod shape to spherical, while the expression of interferon-? remained almost constant.
  • Mojgan Bandehpour, Negar Seyed, Mehdi Shadnoush, Parviz Pakzad, Bahram Kazemi Page 239
    Chlamydia trachomatis is one of the main causes of Sexually Transmitted Diseases (STDs) such as prostatitis and epididymitis in men and cervicitis, endometriosis, vaginitis and ureogenital tract infections in women. Serological tests with sensitivities related to specific antigens are commonly used as routine laboratory tests for diagnosis of Chlamydia. In this research the Chlamydia Major Outer Membrane Protein gene was coloned in order to prepare a specific recombinant protein for use in the ELISA diagnostic kit. DNA was extracted from cultured C. tachomatis. PCR reaction was carried out and the resulting PCR product was cloned into the pGemex-1 expression vector and induced by IPTG (Isopropyl b-D-Thiogalactopyrano side). Recombinant protein was confirmed by gel diffusion, dot blot and western blot, using patients serum. The use of recombinant protein for diagnosis of Chlamydia by ELISA is therefore recommended.
  • Masoud Ahmadzadeh, Hamideh Afsharmanesh, Mohammad Javan Nikkhah, Abbas Sharifi, Tehrani Page 245

    We assessed a collection of 47 fluorescent Pseudomonas spp., some with known biological control activity against certain soil-borne phytopathogenic fungi such as, Macrophomina phaseolina, Rhizoctonia solani, Phytophthora nicotianae var. parasitica, Pythium sp. and Fusarium sp. in vitro and the potential to produce known secondary metabolites such as, siderophore, HCN and protease. The results indicated that 66%, 40.42%, 63.82%, 48.94% and 27.65% of strains revealed antagonistic activity against R. solani, M. phaseolina, Pythium sp., P. nicotianae and Fusarium sp., respectively. Among the 47 strains, 76.59%, 97.87% and 17% produced protease, siderophore and HCN, respectively. In this survey, the detection of phlD and phlA genes was evaluated with a PCR-based assay. We detected phlD in strains P-5, P-32, P-47, and phlA in strains P-5, P-18, P-34 and P-35. Strain CHA0 was used as positive control for the detection of both genes. Overall, there was no obvious link between inhibition of fungal growth in vitro and production of the antifungal metabolites or existence of phlD and phlA genes. Characterization of fluorescent pseudomonads with potential to produce of 2, 4-diacetylphloroglucinol will further enhance our knowledge of their function in the suppression of root diseases.

  • Rajab Choukan, Marilyn L. Warburton Page 254
    The identification of parental inbred lines to develop superior hybrids is a rather costly and time-consuming step in maize breeding. In some cases, pedigree information has been used to select diverse parental lines. In the case of Iranian maize inbred lines, this information is not fully available. In this study we investigated the genetic distance (GD) based on Simple sequence Repeats (SSR) markers between pairs of five maize testers and 28 inbred lines and assessed the relationship between GD and F1 hybrid performance, specific combining ability (SCA) and midparent heterosis (MPH). One hundred and forty testcrosses were evaluated for grain yield in 2003, 2004 and 2005 at two locations, Karaj and Gorgan (only 2004), Iran. Significant positive but low correlations were found between GD and F1 performance, SCA and MPH (0.27**, 0.39** and 0.28**, respectively). Testers affected the magnitude of correlations, with relatively high values revealed in the Mo17 crosses (0.54**, 0.61** and 0.61** for F1, SCA and MPH, respectively) and lowest values in the B73 crosses. Although GD between parents correlated significantly with hybrid performance, the estimates of GD did not consistently identify the best crosses.
  • Hamidreza Seyedabadi, Cyrus Amirinia, Mohammad Hossein Banabazi, Hossein Emrani Page 260
    The present study was to construct a parentage verification system for Iranian Caspian horse. A total number of 45 Caspian horse samples including 14 foals for parentage verification, 17 stallion and 14 mare for individual identification were genotyped. Genomic DNA was extracted from whole blood and the genotype were analysed by PCR procedure and using 7 microsatellite markers (AHT04, HMS03, HMS06, HTG06, HTG07, LEX33 and VHL20). The number of alleles per locus varied from 3 to 4 with mean value of 3.86. The expected heterozygosity was ranged from 0.617 to 0.741 (mean 0.675), and the total exclusion probability (PE) of 7 microstellite loci was 0.973. All markers have relatively high polymorphic information content (PIC) value (> 0.6). All foals were qualified by compatibility according to the Mendelism. This study suggests that the DNA typing method has high potential for parentage testing and individual identification of Iranian Caspian horses.
  • Amir Mohammadi, Mohammad Reza Nassiry, Ghorban Elyasi, Jalil Shodja Page 265
    -lactoglobulin (Coded by the b-lg gene) is the major milk whey protein in ruminants. Studies have shown that this protein is polymorphic in many breeds of sheep as a result of a single base pair substitution in the b-lg gene that also gives rise to RsaI restriction fragment length polymorphism (RFLP). Blood samples were collected from 391 animals belonging to 5 Iranian and 6 Russian sheep breeds. BLg5 and BLg3 primers amplified a 452 bp fragment from exon II of the ovine b-lg gene. RsaI enzyme was used for restriction analysis of PCR products. Overall, the frequency of alleles A and B in the studied breeds were estimated as 0.65 and 0.35, respectively. The genotype BB was not seen in the Iranian and Russian Karakul, except in the Afshari and Finnish Landrace, other populations were in the Hardy-Weinberg equilibrium. Keywords: b-Lactoglobulin; Iranian sheep; Russian sheep; PCR-RFLP; Polymorphism.
  • Mahmmood Malaki, Mohammad Reza Naghavi, Hoshang Alizadeh, Payam Potki, Mehrbanoo Kazemi, Seyed Mostafa Pirseyedi, Mohsen Mardi, Fakhre Tabatabaei Page 269
    TLittle information is available regarding genetic variation in wild wheat relatives from Iran. In this study, genetic diversity of 36 populations of wild einkorn wheat, Triticum boeoticum, was studied using amplified fragment length polymorphism (AFLP) primer combinations. Seventeen AFLP primer combinations led to amplify 979 scorable fragments ranging from 50 to 500 bp and of these, 429 (44%) were polymorphic across the 36 populations. The average Dice genetic similarity between T. boeoticum populations was 0.67 (range= 0.18-0.98). The dendrogram derived by unweighted pair group method with arithmetic mean algorithm (UPGMA) analysis revealed three main groups. PCO analysis also confirmed subgrouping obtained by cluster analysis. The measured relative genetic distances among accessions was not correlated with geographical distances of places of their origins, indicating that the populations are genetically different. The results demonstrated that AFLP technology is a suitable technique for genetic resource management in T. boeoticum populations of these studied origin sites.