Iranian Journal of Biotechnology
Volume:3 Issue: 3, Summer 2005

Variability in the cultivated germplasm for economic traits such as resistance to rice tungro virus, sheath blight, yellow stem borer, drought and salt tolerance is limited. This necessitated search for the genes in secondary and tertiary gene pool of genus Oryza. Fortunately, wild species are an important reservoir of useful genes for resistance to major disease, pests and tolerance to abiotic stresses. Wide hybridization in Oryza is normally difficult to achieve because many wild species of genus Oryza are difficult to cross with cultivated rice because of difference in chromosome number or genetic constitution. Fertilization may occur, but the embryo is aborted. Embryo rescue is used to maintain the hybrid embryos and F1s through several cycles of back crosses until fertility is restored. Interspecific hybridization has been attempted by a number of workers and resulting hybrids and progenies have been used for taxonomic and phylogenic analysis with limited efforts to transfer desirable traits from wild species to cultivated rice. Transfer of grassy stunt virus resistance from one accession of O. nivara has been achieved successfully. Another species belonging to the AA genome, O. longistaminata has been exploited for transfer bacterial blight resistance gene to cultivated rice. Wild species with genomes non-homologous to the AA genome of O. sativa such as O. officinalis (CC), O. australiensis (EE) and O. minuta (BBCC) possessing resistance to brown planthooper, white backed planthopper, bacterial blight and blast have been used to transfer these desirable alien traits to cultivated rice. Therefore, wide hybridization is one of the key components in programme aiming at transferring alien genes from diverse sources surmounting sexual barriers. Advances in embryo rescue, anther culture, chromosome engineering and genetics have facilitated in the transfer of genes and in precise monitoring and characterization of alien introgression from different genomes of Oryza into cultivated rice. Integrating conventional breeding with advanced methods of alien introgression offers great potent to develop disease and insect resistant varieties.

A high efficiency shoot organogenesis from callus cultures and plant establishment protocol has been developed for cotton (Gossypium hirsutum L. cv SVPR-2) through shoot tip. After 6 weeks of culture, green-compact-nodular organogenic callus induction was observed on the medium fortified with (MS) basal salts, B5 vitamins, 2.0 mgl-1 of benzylaminopurine (BAP), 1.0 mgl-1 kinetin (KN), 30 gl-1 glucose and 8 gl-1 agar. The highest rate of shoot proliferation was achieved at 12th week and 8.6 shoots were produced per callus clump. Among the different concentrations tested media fortified with MS salts, B5 vitamins, 2 isopentynyl adenine (2-iP) (1.5 mgl-1), gibberellic acid (GA3) (0.6 mgl-1), glutamine (25 mgl-1) and glucose (30 gl-1) showed best response for multiple shoot proliferation from the induced callus. All the in vitro regenerated shoots were rooted on the medium fortified with MS salts, B5 vitamins, 30 gl-1 sucrose, 8 gl-1 agar and 1.5 mgl-1 of indole butyric acid (IBA). The regenerated plantlets, with tertiary roots are considered as matured plantlets and they were hardened on paper pots containing sand, soil and vermiculite in 1:1:1 ratio. The hardened plants showed 85% survival rate and showed parental phenotypic characters.

It is now widely accepted that calcium (Ca) deficiency is linked to potato (Solanum tuberosum L.) tuber disorders and improved tuber health is expected through increased Ca availability. The purpose of this study was to optimize the Ca concentration in Murashige-Skoog (MS) basal medium for microtuber production and determine microtuber mineral composition, especially Ca content. The response of cultivars Bintje and Russet Burbank to the Ca concentration in the media including 3 (control), 10, 15, 20, or 25 mM was different for most parameters measured. Ca at 10 mM concentration improved overall performance of Bintje but not Russet Burbank, compared to controls (3 mM Ca). Higher levels of Ca in the medium were somewhat toxic to both cultivars. Increased Ca concentration in the medium did not affect final shoot fresh weight (SFW) in Bintje but reduced it in Russet Burbank compared with control medium. Ten mM Ca increased microtuber number by 19% in both cultivars. It also increased microtuber fresh weight by 19.5% in Bintje with no effect on Russet Burbank. Mean tuber weight was not affected in Bintje but was decreased by 17% in Russet Burbank. Harvest index in both cultivars was slightly improved at 10 mM Ca but higher levels reduced this index significantly. Microtuber tissue Ca content was greatly increased by Ca treatment in both cultivars. Maximum increase was observed at 15 mM Ca (70%) and 10 mM Ca (61%) in Bintje and Russet Burbank, respectively. Ten mM Ca also increased P (25%) and K (19%), in Bintje whereas in Russet Burbank only P was increased up to 20% at this level of Ca. Unlike Zn, accumulation of other microelements were affected rather differently in two cultivars. Ten mM Ca had no reducing effects on Fe, Mn and Cu accumulation in Bintje whereas it had significant reducing effects in Russet Burbank. It is concluded that the conventional concentration of Ca in MS medium (3 mM) is not high enough for optimum microtuberization. Hence, it appears that optimization of the Ca concentration is necessary for each cultivar.

The D-loop region is a hot spot for mitochondrial DNA (mtDNA) alterations, containing two hypervariable segments, HVS-I and HVS-II. In order to identify polymorphic sites and potential genetic background accounting for Hypertrophic CardioMyopathy (HCM) disease, the complete non-coding region of mtDNA from 31 unrelated HCM patients and 45 normal controls were sequenced. The sequences were aligned upon the revised Cambridge Reference Sequence (rCRS) and any incompatibilities were recorded as numerical changes in homoPolymeric C Tract (PCT), single base substitutions, insertions and deletions (Indels). Nucleotide substitutions were found to make up the majority of the mutations, rather than indels. We drew significantly high transition rate (81.8%) versus lower frequency of transversions (18.2%). 12 polymorphisms were identified in this study which had not been published in the MitoMap database. PCT changes at position 303-309 were detected in 83% of our samples. Our results suggest that an increased level of HVS-I and HVS-II substitutions may be an indicator of mitochondrial DNA instability. Furthermore, mtDNA mutations may play an important role in pathogenesis of cardiac arrest which has remained unexplained for long.

Bladder cancer is one of the most common forms of cancers in the world. The current gold standards for its diagnosis are cystoscopy and urine cytology. Cystoscopy, a naked eye assessment of the bladder, is invasive, uncomfortable and costly with a great deal of personal variability in its results; while urine cytology has high specificity but low sensitivity, particularly for low-grade lesions. Therefore, there is a need for a molecular tumor marker assay capable of detecting bladder cancer with high sensitivity and specificity. A growing list of tumor markers in urine has been introduced so far, but neither of them has been able to replace the current diagnostic methods. Survivin, an inhibitor of apoptosis (IAP) capable of regulating both cell proliferation and apoptosis, has been recently defined as a universal tumor antigen and as the fourth most significant transcript expressed in human tumors. It has been reported to have 100% sensitivity and 95% specificity for detection of bladder cancer. In the present study, the sensitivity and specificity of survivin as a tumor marker in detecting new and recurrent cases of bladder cancer has been evaluated by nested RT-PCR technique. Our results revealed that survivin could be detected in most patients (11/13, sensitivity=0.84) as well as some healthy volunteers with no obvious sign of bladder cancer (6/13, specificity=0.53). Also, in this work, for the first time, the presence of two alternatively spliced variants of survivin (survivin-2B and survivin-DEx3) urine is being reported. Interestingly, the presence of survivin-DEx3 was better correlated with malignant lesions of bladder compared to the survivin expression (sensitivity=0.84, specificity=0.92).

Advances in the field of antibody engineering, and the emergence of powerful screening technology such as filamentous phage display allowed to generate fully human antibodies with high affinities against virtually any desired target from immune or even naIve human repertoires. As a result, the immunogenicity problems related to applications of non-human based recombinant antibodies as therapeutic reagents in human were bypassed. In this study, we constructed large human immunoglobulin libraries from the lymph nodes of breast carcinomas patients in two different formats of single-chain fragments of variable domains (scFv) of antibodies. The heterogeneity of the libraries were tested by restriction enzyme analysis and sequencing on DNA samples of randomly selected colonies. Functional expression of the selected scFv molecules in E. coli was demonstrated by Western blotting. Phage rescue and panning of these libraries against the candidate tumor antigens will lead to the identification of novel human scFvs for tumor detection and pave the way towards the generation of a fully human IgG with desired effector functions for possible future tumor therapy.

Display of peptides on the surface of bacteria offers many new and exciting applications in biotechnology. Fimbriae is a good candidate for epitope display on the surface of bacteria. The potential of CS3 fimbriae of enterotoxigenic E. coli as a display system has been investigated. A novel cell surface display system with metal binding property was developed by using CS3 fimbriae. Short metal binding peptide, Gly-Cys- Gly-Cys-Pro- Cys- Gly- Cys- Gly as a cysteine rich peptide, was inserted into CS3 fimbriae and displayed on the surface of E. coli. Bacteria expressing hybrid pili with cysteine rich peptide could adsorb 392.5, 510 and 905 nmol of Ni2+, Cd2+ and Pb2+ per mg (dry weight) of cells, respectively, which are five-fold (nickel) and three-fold (cadmium) more than E. coli expressing native pili. Thus, expression of Cys-rich peptide enables bacteria to act as a metalloaffinity adsorbent. These results open the possibility for biosorption of heavy metal ions using engineered microorganisms.

Nodal explants of Phyla nodiflora (L.) Greene, were cultured on Murashige and Skoog (MS) medium supplemented with different combination and concentration of cytokinins and auxins for multiple shoots regeneration. The maximum numbers of shoots were found in MS medium supplemented with 2.5 mgl-16-benzylaminopurine (BA) and 0.5 mgl-1 kinetin (KN). Elongated shoots were transferred to rooting medium containing quarter strength or half strength or full strength MS medium supplemented with Indole acetic acid (IAA) or Indole-3-butyric acid (IBA). Highly efficient roots were promoted on half strength MS medium supplemented with 1.0 mgl-1Indole-3-butyric acid (IBA). Rooted plantlets were successfully acclimatized and established in soil. This protocol could be very useful for mass cultivation of phyla nodiflora (L.). In present study, we have established higher frequency of shoot regeneration from nodal explants of phyla nodiflora

The present study has been designed to find out the effects of forced swimming-induced oxidative stress imposition on primary and secondary sex organs and its protection by plant extract in male Wistar strain rats. This work has been designed to find out the scientific basis of the local use of the composite extract of root of Withania somnifera، leaf of Ocimum sanctum and rhizome of Zingiber officinale by village Ayurvedic doctors to protect the health disorders in connection to strenuous physical exercise، and also to search out the potentiality of above mentioned plant products on swimming-induced oxidative damage. Forced intermittent swimming for 8 hours /day for 28 days resulted a significant elevation in the level of products of free radical i. e.، thiobarbituric acid reactive substances and conjugated dienes along with significant diminution in the activities of catalase، superoxide dismutase and glutathioneStransferase in testis، prostate and seminal vesicle which were protected significantly after co-administration of methanolic extract of said plant parts in composite manner. Testicular steroidogenesis was assessed in this condition by measuring plasma levels of testosterone، which was diminished significantly in swimming group and was protected significantly by the composite extract of the plants parts. The antioxidative potency of this composite extract was compared with potent and standard antioxidant i. e.، vitamin-E in forced swimming state. This herbal extract has no toxic effect on metabolic organs that has denoted here by the measurement of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities in liver and kidney. The results suggest that swimming-induced oxidative stress on male sex organs may be protected by using above mentioned medicinal plants extract.