Iranian Journal of Biotechnology
Year:2012 | Volume:10 | Issue:1|Papers Count:10

Identification of drug resistant mutations is important in the management of HIV-1 infected patients. The aim of the current study was to evaluate drug resistance profile of RT gene and assess subtypes among the HIV-1 circulating strains and intensification of physician’s options for the best therapy. HIV-1 RNA of 25 samples was extracted from plasma and RT Nested- PCR was performed and the final products were sequenced and phylogenetically analyzed. Stanford HIV drug resistance sequence database was used for interpretation of the data. The results of phylogenetic analysis showed subtypes A1 and B in 14 (58%) and 10 (42%) patients respectively. Of the 24 patients, 16 (66.6%) had resistance to NRTIs, 8 individuals (32%) to NNRTIs and one patient was susceptible to NRTIs as well as NNRTIs. The drug resistance interpretation in this study showed: 87.7% susceptible for AZT, 70.8% susceptible, and 25% high-level resistance for 3TC, 87.7% susceptible for TDF, 29.1% high-level resistance for NVP and 70.8% susceptible and 25% high-level resistance for EFV. Our data suggests that probably, the use of 2 NRTIs plus 1 protease inhibitor (PI) regimen is more effective than 2 NRTIs plus 1 NNRTI regimen in Iranian patients that use 2 NRTI plus NNRTI regimen and also continuous surveillance should be perform to evaluate resistance patterns for more effective therapeutic approaches.

There are questions concerning the functions of artemin, an abundant stress protein found inArtemia during embryo development. It has been reported that artemin binds RNA at high temperaturesin vitro, suggesting an RNA protective role. In this study, we investigated the possibility of the presence of RNA-binding sites and their structural properties in artemin, using docking energy landscapes and molecular dynamics simulation. Analysis of docking energy landscapes revealed sites in artemin with the potential of binding RNAs. We found a good agreement between RNA-binding sites of artemin and RNA-interacting sites of a specific group of RNA-binding proteins called PUF, as regards to the type of their interactions with RNA molecules. Furthermore, the results from molecular dynamics simulation showed that firstly, the presence of RNA molecule and its interaction with artemin cause significant decrease in the secondary structure content of artemin; secondly, RNA-binding sites are mostly located in the low flexible regions. Finally, it seems that these binding sites are distributed in such a way that leads RNA molecule into the interior of the protein, strengthening the previous suggestion for RNA-protecting role of artemin.

Measuring the viability of probiotic microorganisms in food products using plate count methodology is a common practice due to the simplicity (ease of performance), inexpensive and routine testing characters of this method. In present study, the suitability of de man rogosa and sharpe agar (MRS) bile agar medium for the selective enumeration of mixed probiotic bacteria (Lactobacillus acidophilus LA-5, L. casei 431 and Bifidobacterium lactisBB-12) in presence of mesophilic lactic cultures (Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris) and yoghurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckiissp. bulgaricus) was investigated. Yoghurt bacteria did not grow neither in presence of 0.15% nor 0.30% of bile salts, as was expected. Mesophilic lactic starters could grow at both concentrations of bile salts at all incubation temperatures except 37oC. According to these results, MRS-bile agar (0.15 bile salts) could be successfully used for selective enumeration of mixed probiotic cultures in presence of mesophilic culture and/or yoghurt bacteria when plates were incubated at 37oC for 72 h.

Metabolism of the alpha-1, 1 glucose disaccharide, trehalose, is indispensable in plants. In the Murashige and Skoog (MS) medium, trehalose inhibits plant growth and allocation of carbon to roots. A suppressor of trehalose-6-phosphate (T6P) mediated growth arrest, GR-RBP2, is characterized in more detail. Phylogenetic analysis revealed that GR-RBP2 is a protein of likely prokaryotic origin. A knockout mutant of GR-RBP2 was identified in the T-DNA insertion line SALK-059714, yet plants of this line were not altered with regard to growth on different carbon sources and on trehalose compared to WT. GUS expression analysis showed thatGR-RBP2 was detected in adult leaves, flowers and siliques. Expression was particularly high in root tips. GR-RBP2 expression also is insensitive to 100 mM trehalose. TAP-tagged versions of this protein showed that GR-RBP2 is part of a protein complex in planta.

Phenylalanine amonia-lyase (PAL) is one of the most important enzymes that plays a key role in regulation of phenylpropanoid production in plants. It catalyzes the first step of the phenylpropanoid pathway in which L-phenylalanine is deaminated to trans-cinnamic acid. This step is significant for metabolic engineering and hyper-expression of the major phenylpropanoid, methyl chavicol. We followed gene expression and activity of PAL in Ocimum basilicum L. at different stages of growth including seedling, beginning and middle of growth phase, budding stage and flowering, and their correlation with final concentration of phenylpropanoid compounds. The level of gene expression was monitored by semi quantitative RT-PCR and phenylpropanoid compounds were identified by gas chromatography/mass spectrometry (GC/MS). PAL activity was assayed using spectrophotometer. The results indicated that the level of gene expression and activity of PAL enzyme are altered during the plant development, where the highest expression and activity (0.851μmol cinnamic acid/mg/min) was achieved at budding stage. In this experiment, changes of methylchvicol content were correlated to the transcription and activity of PAL enzyme.

The response to drought stress is a complicated process involving stress sensing, intracellular signal transduction, and the execution of a cellular response. Transcription factors play important roles in the signaling pathways including abiotic stress. In the present study a rice NF-YA transcription factor gene was partially characterized following dehydration. Disrupting the gene via a T-DNA insertion resulted in drought tolerant plants and a high rate of recovery after water resupply. It was demonstrated that the improved drought tolerance of the mutant is primarily due to non-stomatal mechanisms such as free radical scavenging, which might be related to changes in metabolism of carbohydrates.

Typhoid disease or salmonellosis is a common sickness in horses. In several epidemiological studies in hospitalized horses, several serotypes of Salmonella often are predominant in nosocomial infections. Transportation, overcrowding, dehydration, oral antimicrobial therapy and infections are the risk factors which may activate latent or subclinical salmonellosis. In this study, the occurrence of typhoid due to Salmonella serogroup B was considered in a Caspian ponies flock kept in a husbandry center of ponies around Tehran. During transportation of 19 ponies, two pregnant ponies aborted and four cases died because of acute septicemia. Pathological and bacteriological follow up showed salmonellosis. A multiplex polymerase chain reaction (m-PCR) assay was used for detection and identification of Salmonella to confirm pathological and bacteriological studies. Salmonella Typhimurium was isolated from bone marrow, mesenteric lymph nodes, liver and intestinal contents of died pony. Salmonella was not isolated from stools of other ponies. Pulsed Field Gel Electrophoresis (PFGE) and antibiotic susceptibility test were also performed. PFGE pattern was similar to the other collected isolates which have existed since more than 30 years ago in Iran. Because of importance of salmonellosis in ponies, using rapid methods are recommended to confirm the presence of Salmonella. Results showed that m-PCR permit to evaluate samples more rapidly than other methods and also can detect multiple genes simultaneously like virulence factors which declare virulence of the isolates and have surveillance significance.

Fusion protein technology represents the strategy to achieve rapid, efficient, and cost-effective protein expression. Epsilon and Beta toxins are the most potent Clostridial toxins and cause disease in animals. This study describes in silico fusion of Clostridium perfringens types D and B epsilon and beta toxin genes that was used for cloning in E. coli. The etx and cpb genes were retrieved from the GenBank and a fusion gene was designed to produce a chimeric fusion protein. Secondary and tertiary structures and specificities of fusion protein were determined by online software. Results showed that the designed fusion gene construction is suitable for chimeric fusion protein expression.

Bacillus clausii TnrA transcription factor is required for global nitrogen regulation. In order to obtain an overview of gene regulation by TnrA in B. clausii KSMK16, the entire genome of B. clausii was screened for the consensus sequence, 5’-TGTNAN7TNACA-3’ known as the TnrA box, and 13 transcription units were found containing a putative TnrA box. The TnrA targets identified in this study were tnrA, glnA, nrgA, nasFDEB, puc genes, licT, the two operons of the oligopeptide ABC transporter, lytR, transcriptional regulator of the Lrp/AsnC family, sodium-dependent transporter of SNF family, hyu genes and a biochemically uncharacterized protein.