Iranian Journal of Biotechnology
Volume:3 Issue: 2, Spring 2005

Pneumoviruses are responsible for significant respiratory disease in their hosts and represent a major problem for human and animal health. Pneumoviruses are members of the family Paramyxoviridae، subfamily Pneumovirinae and the virus particles consist of a negative-sense، nonsegmented RNA genome within a helical nucleocapsid structure enveloped in a lipid membrane derived from the host cell. Over the past four decades much work has extended our understanding of the molecular biology and pathogenesis of pneumoviruses but despite this only limited treatments and prophylaxis are available. The human pathogen، respiratory syncytial virus (hRSV) which belongs to the genus of Pneumovirus is the best characterized of the subfamily. HRSV is the major cause of hospitalisation of very young children with respiratory disease worldwide. No vaccine is available though new treatments offer some respite for children in the highest risk groups، the immunocompromised and children with congenital heart disease. The recently discovered human pathogen human metapneumovirus (hMPV) belongs to the genus Metapneumovirus and recent data indicates that this virus is second only to hRSV in terms of disease impact. The pneumoviruses also include agents of veterinary importance such as bovine respiratory syncytial virus (bRSV)، ovine and caprine RSV، and pneumonia virus of mice (PVM: all in the genus Pneumovirus) and avian metapneumovirus (APV: genus Metapneumovirus). The development of reverse genetics systems for negative strand RNA viruses has opened the possibility of manipulating the virus genomes to identify genes involved in pathogenesis and to explore the biological consequences of specific mutations. This information is informing the rational design of new vaccines. These plasmid-based systems have shown that for all paramyxoviruses the N، P and L proteins are necessary and sufficient for RNA replication. However، the pneumoviruses differ from the other family members in that fully efficient transcription from the virus genome requires the presence of an additional protein encoded by the M2 gene. The present article reviews pneumovirus biology and molecular genetics including a discussion of current concepts of Pneumovirus reverse genetics.

In the present study, using anti-sense oligonucleotides the inhibition of expression of the PML protein has been investigated. The anti-sense oligonucleotides were designed against the translation initiation site of the PML gene, and their effects were investigated on cellular growth and DNA synthesis. Incubation of normal human fibroblast cells with the anti-sense oligonucleotides resulted in the complete inhibition of the PML protein expression. Inhibition of the PML protein expression by anti-sense oligonucleotides was found to be associated with an increase in cellular growth and doubling time. Furthermore, in cells treated with the anti-sense oligonucleotides, but not sense or scrambled oligonucleotides (control), the cellular DNA synthesis also showed a marked increase, confirming the induction of cellular growth upon inhibition of PML synthesis. These findings clearly demonstrated that the inhibition of the expression of the PML protein could be achieved using the anti-sense oligonucleotides, providing a model for better investigation of the biologic role of PML in the cell

Molecular typing of twenty-five Pasteurella multocida isolates has been assessed by restriction fragment length polymorphism (RFLP) of a species-specific PCR assay. Amplification was based on the gene ompH, encoding a major outer membrane protein. RFLP analysis of the 1.2 kb ompH-amplification using EcoRI, HindIII and CfoI endonucleases produced 7 different patterns for the twenty five isolates of the four P. multocida serotypes. The PCR-RFLP of the ompH gene was found to be potentially a useful method for typing of P. multocida and therefore, for studying the epidemiology of P. multocida infections.

The use of polymorphic markers in breeding programmes could make selection more accurate and efficient. A total of 324 individuals from six Iranian cattle populations (Sarabi، Golpayegani، Sistani، Taleshi، Mazandarani، Dashtiyari)، F1 Golpayegani Brown Swiss and Iranian buffalo populations were genotyped for the Pit-1 HinfI and leptin Sau3AI polymorphisms by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The genotype and gene frequencies for each breed were determined and shown to be quite variable among the breeds. The highest frequencies of allele B for the leptin gene and allele A for the Pit-1 gene were found in Dashtiyari and Sistani cattle، respectively. According to our results، the highest AB genotype frequencies were found in the Taleshi and F1 Golpayegani x Brown Swiss cross for the leptin and Pit-1 genes، respectively. These allele frequencies were comparable to previously published data on exotic breeds. The highest and lowest heterozygosities were found in Taleshi and Dashtiyari cattle for the leptin gene and in F1 Golpayegani x Brown Swiss cross and Sistani cattle for the Pit-1 gene، respectively. These values indicated the presence of low variation for these genes in the studied populations. The possible association between molecular polymorphisms within these candidate genes and economic traits for the studied populations should be further investigated. Keywordظ.

Using agro-infiltration technique, we have transiently expressed human Growth Hormone (hGH) in tobacco (Nicotiana tobacum), potato (Solanum tuberosum) and lettuce (Lactuca sativa) leaves. Out of three different inoculation times used for infiltration in our study, it was seen that highest level of hGH expression was achieved when leaves were infiltrated for 35 min. The presence of biologically active hGH was detected in leaf extract by western blotting and ELISA. The highest expression was measured in tobacco was found to be1.5-3 hGH mg/kg leaves.Keywords

In the present study, three chromium resistant bacterial strains (CrT-1, CrT-2, CrT-3) which could resist very high concentration of K2CrO4 (up to 40 mg ml-1 on nutrient agar plates and 10 mg ml-1 in acetate-minimal medium) were used to inoculate the sunflower seeds both as control and under chromium stress. Cr(VI) caused severe reduction in different growth parameters (seedling length, fresh weight, dry weight g-1 fresh weight) as compared to control, while bacterial inoculations improved different growth parameters both as control and under chromate stress when compared with non-inoculated respective controls. With respect to biochemical parameters, acid phosphatase and auxin content showed marked increment with bacterial inoculation both in chromium stress and unstressed condition. Uptake of chromium in inoculated plants decreased significantly as compared to non-inoculated control. Cr (VI) application also severely damages different plant cells/tissues but bacterial inoculation not only improves the growth and yields parameters but also prevent cell damages caused by the Cr (VI) salt.Keywords

Neuropeptide Y (NPY) is a 36 amino acid peptide found throughout the central and peripheral nervous system of rat and human. NPY has been proposed to play an important role in satiety. The aim of this study was to produce cell lines that secrete high levels of bioactive NPY. For this purpose, the complementary DNA (cDNA) that encodes NPY was isolated by PCR. The cDNA was then cloned into pCEP4, to form pCEP4NPY. 6-23 cells were transfected with pCEP4NPY by electroporation. Transfected cells were selected by the addition of hygromycin B to the culture medium. Resistant colonies were picked and transferred to 96-well plates. The medium was tested for IR-NPY using a specific NPY radioimmunoassay (RIA). The IR-NPY secreted by the cells was characterized by sephadex G50 chromatography and reversed phase fast protein liquid chromatography (FPLC). It was found to co-elute with the synthetic standard in both cases. RNA was extracted from the cells and subjected to Northern blot analysis using labeled NPY cDNA as a probe. The cells were found to express high levels of NPY at mRNA levels.

To prevent distribution of recessive alleles in dairy herds all bulls used for AI (Artificial Insemination) have to be tested. In this study 26 blood and 4 semen samples were supplied from Iranian Holstein bulls used for AI. Genomic DNA was extracted from 100 ml of blood and 200 ml of semen. Samples were tested by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. PCR reaction was performed for amplification of polymorphic region of the CD18 gene on chromosome 1 and exon 5 of ASS gene on chromosome 11. We detected one Bovine Leukocyte Adhesion Deficiency (BLAD) carrier and no carrier for bovine Citrolliemia in this study. Hardy-Weinberg test confirmed the equilibrium of BLAD locus in this population.Keywords