فهرست مطالب

Iranian Journal of Biotechnology
Volume:8 Issue: 4, Autumn 2010

  • تاریخ انتشار: 1389/07/01
  • تعداد عناوین: 8
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  • Mossa Gardaneh Page 213
    Cell-gene therapy is a dynamic constituent of novel medical biotechnology. Neurodegenerative disorders in which damage to or demise of specific brain cell types plays central role, are clear examples of disease candidate for cell replacement therapy. Dopaminergic (DAergic) neurons biosynthesize dopamine, a vital neurotransmitter in the central nervous system. Due to the involvement of dopamine in a number of critical physiological functions in human and other mammals, disturbed dopamine neurotransmission resulting from DAergic neuron death or damage causes a few known disorders most prominently Parkinson’s disease (PD). DAergic cell replacement therapies proposed as promising approaches for PD treatment have prompted scientists to thoroughly investigate the embryonic development of DAergic neurons and their function in ordinary life. This review summarizes past and current findings in DAergic neuron development and survival. It also briefly looks at the future prospect of DAergic neuron generation in vitro aiming at clinical applications in vivo.
  • Yousef Mortazavi, Fatemeh Mirzamohammadi, Majid Teremahi Ardestani, Ebrahim Mirimoghadam, Tom J. Vulliamy Page 229
    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an enzymopathy affecting about 400 million people worldwide. The distribution of G6PD deficiency and the molecular genetics of this enzyme vary widely among different ethnic groups. The aim of this study was to find out the frequency of G6PD deficiency and characterize the Mediterranean type mutationin deficient individuals in Turk, Balouch and Fars ethnic groups in Zanjan, Iranshahr and Tehran provinces. 1500 unrelated male individuals from Zanjan and 305 unrelated male students from Iranshahr were screened for G6PD deficiency by fluorescent spot test. Genomic DNA was extracted from deficient individuals and also from 64 G6PD deficient individuals from Tehran city. PCR was used to amplify flanking regions of exons 6 and 7 of this gene. The PCR products were digested by the MboII enzyme and electrophoresed on 3% agarose gel. Thirty-three (2.2%) individuals were shown to be deficient for G6PD from Zanjan population. Twenty-four out of 33 (72.8%) of the deficient individuals showed a mutation at nt 563 which is characteristic of Mediterranean type of mutation. Nine individuals were negative for this mutation. Fifty nine (19.3%) individuals of Iranshahr were shown to be deficient for G6PD. At the molecular level, 50 (85%) of the individuals showed Mediterranean type of mutation and 15% were negative for this mutation. Our results from Tehran showed that 47/64 (73.4%) of deficient individuals had Mediterranean type mutation and 26.6% were negative for this mutation. Despite different frequencies exist for deficiency of G6PD in Turk, Balouch and Fars populations, the results of the present study and others have shown that the predominant mutation of G6PD in Iran is of Mediterranean type.
  • Mohamadreza Baghaban Eslaminejad, Fatemeh Bagheri, Mojgan Zandi, Elham Nejati, Elham Zomorodian, Houri Mivehchi Page 234
    Bones constructed by tissue engineering are being considered as valuable materials to be used for regeneration of large defects in natural bone. In an attempt to prepare a new bone construct, in this study, proliferation and bone differentiation of marrow-derived mesenchymal stem cells (MSCs) on our recently developed composite scaffolds of nano-, micro-hydroxyapatite/ poly(l-lactic acid) were compared with pure poly(l-lactic acid) scaffolds. For this purpose, some passaged-3 rat MSCs were three-dimensionally cultivated on the scaffold surfaces and their morphology was observed with scanning electron microscopy. Cell proliferations on different scaffolds were examined by MTT assays. Osteogenic cultures were established with the scaffolds loaded with MSCs for 21 days at the end of which culture mineralization; the cell alkaline phosphatase (ALP) Level and the relative expression of selected bone specific genes were quantified and compared to each other. Our results indicated that the cells having been adhered and assumed spherical morphology were able to proliferate in all studied scaffolds. The microenvironment provided by nano-scaffolds appeared much better medium than those of micro-scaffolds and pure PLLA (P < 0.05). The osteogenesis assays indicated to the superiority of nano-scaffolds in supporting MSCs undergoing bone differentiation, which was reflected in high cellular ALP levels, increased bone-related gene expression and enhanced culture mineralization. Collectively, the bone construct prepared with nano-hydroxyapatite/ poly (l-lactic acid) scaffold and proliferated MSCs would be suitable candidate for use in bone regenerative medicine.
  • Nahid Bakhtiari, Manouchehr Mirshahi, Valiollah Babaeipour, Nader Maghsoudi Page 243
    Expression of foreign proteins in E. coli is normally inhibited by exogenous production of acetate. To overcome this problem, various strategies have been proposed and tested to reduce the extent of acetate accumulation. Although these strategies can improve the outcome, the implementation of their proposed techniques is not practical. Because to achieve optimal results, it requires extremely tight control conditions and the actual cost is very high. Furthermore, a simple knockout mutation of the target metabolic pathway would not be appropriate because the acetate pathway plays an important physiological role in E. coli. In this study, we employed an antisense RNA strategy as an elaborated metabolic engineering tool to partially block biosynthesis of two major acetate pathway enzymes, acetate kinase (ACK) and phosphotransacetylase (PTA). The fragments of antisense cassette were cloned sequentially in pBluescriptsk+ and completed cassette subcloned in pLT10T3. The function of this cassette was evaluated with RT-PCR and ACK and PTA assay. The effect of cassette on cell physiology was monitored by determination of optical density, glucose consumption and acetate production. We found that the antisense method partially reduced mRNA levels of the target genes, lowered the concentration of acetate in culture media and increased growth rate and final cell density in antisense-regulated strain. This strategy could provide us with a useful, inexpensive and practical tool to achieve a large-scale protein production system.
  • Mandana Zarei, Saeed Aminzadeh, Hossein Zolgharnein, Alireza Safahieh, Ahmad Ghoroghi, Abbasali Motallebi, Morteza Daliri, Abbas Sahebghadam Lotfi Page 252
    Chitinase production by newly isolated Serratia marcescens B4A was optimized following Taguchi’s array methods. Twenty-three bacterial isolates were screened from shrimp culture ponds in the South of Iran. A chitinase-producing bacterium was isolated based on it’s ability to utilize chitin as the sole carbon source. The isolate designated as B4A, was identified as Serratia marcescens based on its 16S rRNA sequence and key morphological, physiological and biochemical characteristics. The cultivation of Serratia marcescens B4A in the appropriate liquid medium resulted in production of high levels of chitinase. The malt extract and colloidal chitin represented the best nitrogen and carbon sources, respectively. Chitinase production by Serratia marcescens B4A was optimized following the Taguchi orthogonal array (OA) for the design of experiments (DOE). Statistical experimental design via the Taguchi method was applied to determine the optimal levels of physical parameters and key media components in the medium, such as temperature, pH, NaCl and chitin concentrations. The results of this study showed that temperature of 30ºC, pH 7.9, NaCl 0.1% (w/v) and chitin 1% (w/v) are optimal conditions for this protocol.
  • Meena Kochappan Cheruvathur, John Britto, Dennis Thuruthiyil Thomas Page 263
    An efficient plant regeneration method was established for Caesalpinia bonduc (L.) Roxb. by culturing immature epicotyl explants. Morphogenic calli were initiated from 96% of epicotyl explants on MS medium supplemented with BA (6-benzylaminopurine) 4.0 mg/l and NAA (Naphthalene acetic acid) 1.0 mg/l. The calli formed were excised and subcultured on MS medium fortified with 1 mg/l 2, 4-dichlorophenoxyacetic acid (2, 4-D) for further proliferation. Maximum percent organogenesis (84%) and average shoots per culture (5.6) was observed on MS medium fortified with 3.0 mg/l BA and 1.0 mg/l IAA (indole-3- acetic acid). Addition of indole-3-butyric acid (IBA) in ½ MS medium favored rooting of recovered shoots. Out of 30 rooted shoots transferred to soil 27 survived after acclimatization.
  • Sohrab Boozarpour, Majid Sadeghizadeh, Mohammad Ali Shokrgozar, Saman Hosseinkhani, Seyed Abbas Shojaosadati, Sara Gharavi, Ghasem Ahangari, Bijan Ranjbar Page 270
    Selection of a system for successful recombinant protein production is important. The aim of this study was to produce high levels of human interleukin-2 (hIL-2) in soluble form. To this end, the pET32a vector in Escherichia coli BL21 (DE3) was used as an expression system, since it was previously used for the production of mouse IL-2 in soluble form. The results indicated that contrary to expectations, the expressed protein was in the form of inclusion bodies and perhaps amino acid differences between human and mouse IL-2 should be determinant. The hIL-2 protein is a small peptide, therefore its recovery as a biologically functional protein by the process of refolding may be feasible and could lead to high yields at the industrial scale.
  • Mohammad Reza Sarikhani, Mohammad Ali Malboobi, Nasser Aliasgharzad, Ralf Greiner, Bagher Yakhchali Page 275
    Phosphatase (APase) enzymes including phytases have broad applications in diagnostic kits, poultry feeds, biofertilizers and plant nutrition. Because of high levels of sequence diversity among phosphatases, an efficient functional screening method is a crucial requirement for the isolation of the encoding genes. This study reports a functional cloning screening method for the isolation of APase-encoding genes from bacterial genomic libraries in a medium containing a chromogenic substrate. The method was optimized to distinguish the desired signal from the background chromosomal APase activity. This screening method led to the isolation of two novel APase-encoding genes from Pseudomonas putida with no similarities to the known genes in the databases, indicating successful implementation of the developed method.