JOURNAL OF MICROBIAL BIOTECHNOLOGY
Year:2009 | Volume:1 | Issue:2 (2)|Papers Count:8

Background and objective: Food born diseases are still one of the most important concerns in the world .Of various pathogens that are related to food born diseases, Staphylococcus aureus is the most common pathogen of food poisoning. Heat stable enterotoxin of methicillin resistant S.aureus (MRSA), which is rapidly spreading in the world, is the major factor in causing food poisoning. The objective of this study was to assess the frequency of food contamination by S.aureus and the prevalence of MRSA strains in tested samples.Material and Methods: In total, 560 food samples from different parts of Tehran south, Shahre Rey and Islamshahr were obtained for the test between January 2008 to September 2008. The detection of S.aureus in the food samples were performed according to National Standard of Iran, No.1194.Results: Of 560 samples, 49(8.7 %) were contaminated with S.aureus. Pastries are the most contaminated among the others. In total 2 %of S.aureus isolates were resistant to methicillin. Conclusion: The high percentage of contamination with S.aureus was found in this study .Since this bacterium is very important in causing food poisoning, we advice strict control in processing and producing of food staff.

Background and objectives: Immunoglobulins are used for getting some information about a specific antigen and affinity chromatography is a method for immunoglobulins separation .The aim of this study was to preparation of recombinant protein A from Staphylococcus aureus for using IgG separation from human serum. Methods: The genomic DNA was extracted from Staphylococcus aureus and PCR reaction was done using a pair of primer based on protein A gene sequence. PCR product was cloned in to cloning vector. Recombinant plasmid was digested with NdeI and EcoRI restriction enzymes .The gene was purified from gel and sub cloned in to an expression vector.Results: The gene of staphylococcal protein A was amplified and PCR product contained 1435 bp sub cloned in to expression vector, successfully and confirmed.Conclusion: The recombinant plasmid is ready to express of recombinant protein for affinity chromatography column preparation.

Background and Objective: Translation initiation region (TIR) significantly affects the level of recombinant protein expression in E .coli. In order to determine this effect we designed a long primer to modify TIR and reduce GC content.Materials and methods: We had pET-1006 (human basic Fibroblast Growth Factor cDNA inserted to pET-22b) as a template .Site directed mutagenesis were applied to alter the 5′ end of hbfgf cDNA and decrease GC content through nucleotide changes, without changing amino acid sequences .The amount of produced hbFGF expressions by mutant and wild gene was quantified based on SDS-PAGE densitometry assay, western blotting and ELISA.Results: Obtained result proved that expression rate of mutant gene was increased when compared to wild type. This serious difference might relate to the mRNA efficiency for translation. Conclusion: It shows that reduction of GC content will decrease the stability of secondary structure of mRNA and cause enhancement in translation.

Background and Objective: Yogurt drink (dough), a popular national drink in Iran is famous for its nutritional values specially calcium and group B vitamin .As a fermented drink, dough also harbors beneficial bacteria which enrich gastrointestinal flora and could combat some bacteria like Escherichia coli O157: H7. Pathogenic food borne bacteria are responsible for diseases such as hemorrhagic colitis and hemolytic uremic syndrome.Materials and Methods: In this study the antagonistic effects of various Iranian doughs (industrial traditional and also acidophilus) were examined on Escherichia coli O157:H7. The kinetics of death of the pathogenic bacteria in various doughs was determined.Results: The results obtained indicated that also all the dough preparations were capable of significant reduction of pathogenic bacteria but this effect for tradition doughs was more significant and within 30 min eradication of pathogenic bacteria was achieved.Conclusion: Considering the effect of each of these time and time will dough nutrient more than an hour long, so do not take the use of probiotic drinks such as yogurt drink local food acidophilus 30 minutes in duration caused a significant reduction in the number of bacteria are the disease can prevent microbial contamination and infection is effectively different.

Background and Objective: H.pylori is a major etiologic agent for several gastroduoedenal diseases including gastric ulcer and peptic ulcer. It has been reported that the Th17 cells strongly associated with inflammatory disease and IL-23 presented as a main inducer of Th17 cells development. The aim of this study was to investigate the serum levels of IL-17 and IL-23 in H. pylori-infected peptic ulcer (PU) patients and H. pylori-infected asymptomatic (AS) carriers.Materials and Methods: Totally, 45 H. pylori-infected PU patients, 30 H. pylori-infected AS carriers and 15 healthy uninfected subjects (as a control group) were enrolled to study. A blood sample was obtained from all participants and the serum levels of IL-17 and IL-23 was measured by ELISA method. Results: The mean serum levels of IL-17 in total PU patients (9.28 pg/ml ± 5.48) was significantly higher than those observed in total AS subjects (5.19 pg/ml ± 3.75, p<0.001) and healthy control group (3.55 pg/ml ± 3.76, p<0.0001) .The mean serum levels of IL-23 in PU, AS and control groups were 8.66 pg/ml ± 8.41, 7.25 pg/ml ± 5.66 and 3.64 pg/ml ± 3.36, respectively .The mean serum levels of IL-23 in PU and AS groups was significantly higher than those found in uninfected control group (P<0.02 and P<0.03, respectively). Conclusion: The results of the present study showed higher serum concentrations of IL-17 and IL-23 in H.pylori-infected subjects as compared with control group.

Background and Objective: Although Helicobacter pylori infection could be eradicated by a combination of therapeutic agents, but sometimes the cure thus achieved is incomplete and undesirable side effects are certain to occur. Orange peel is used as a food additive for flavoring. Iranian people use the orange rind to improve flavor of cake or some foods such as rice. Considering the use of orange peel for digestive disorders in traditional medicine and the increased development of resistance of Helicobacter pylori to antibiotics, we decided to evaluate the anti- Helicobacter pylori activity of orange peel.Materials and Methods: Percolated methanol extract of orange peel were tested against 37 clinical isolated of Helicobacter pylori. Growth inhibition was determined by the filter paper disc diffusion method on modified egg yolk emulsion agar compared with amoxicillin and metronidazole.Results: All of bacterial isolates were sensitive to 2 mg of orange peel extract. The mean of inhibition zone was 13.28±0.45 mm. The minimum inhibitory concentration (MIC) of methanol extract was 729 mg/ml. MBC was more than MIC. Methanol extract preserved its anti- Helicobacter pylori activity after autoclaving for 20 minutes.Conclusion: Screening among natural resources and plants which are used in folk medicine for gastric problems can be benefit .This study demonstrated that orange peel inhibits growth of Helicobacter pylori isolates in vitro. Concerning the other benefits of herbal medicines, using of orange peel is recommended instead of vanillin to prepare foodstuffs such as cakes.

Background and Objective: The emergence of antibacterial resistance enteric gram-negative bacteria is on increase. This may be caused by the use of these agents for the growth promotion or to prevent the infections in animals. The resistance strains can be transferred to human by different routes. Presence of such isolates in animals is important from medical, veterinary and economical points of view. The aim of this study was the identification of enteric bacteria, and their resistance to antibacterial agents in chickens in Kerman. Materials and methods: Samples were taken by swabs from inside the chicken carcasses, and were cultured in the suitable isolation media. Glucose fermenting gram-negative bacteria was identified by the biochemical tests. Minimum Inhibitory Concentration (MIC) to 4 antibacterial agents was determined by standard agar dilution method.Results: Quantitatively the isolation of different enteric bacteria in chickens were Escherichia coli (43.7%), proteus, morganella and providencia group (22.4%), klebsiella, enterobacter, serratia group (21.2 %), and Salmonella, citrobacter, Arizona group (12.5%). Resistance to ciprofloxacin, gentamicin, chloramphenicol and tetracycline was 9.12%, 9.5%, 11.78 %and 57.8 %respectively. Resistance to two or three antibiotics simultaneously was found in 19.78 %of the isolates.Conclusion: High rate of resistance to tetracycline and presence of multiple drug resistance in the bacterial isolates in the chickens is this area is a cause of concern. It is recommended that the poultry industries should pay attention to the addition of antibacterial agents as the food additives in the chickens, and the use of antibacterial agents especially tetracycline should be stopped in our country, like many countries of the world.

Background and Objective: Xylan the major portion of the hemicellulose of plant cell walls are heterogeneous polysaccharides. Xylanases (EC:3.2.1.8) are enzymes obtained from different species of microorganisms that degrade the xylosidic linkages of xylan’s backbone producing xylose with other monoresidues. In recent years, xylanases have many application in industry such as paper biobleaching and oil clearing.Materials and methods: In this study xylanase enzyme was purified from culture supernatant of Bacillus stearothermophilus (ATCC 12980) by ammonium sulfate precipitation, gel filtration on sephadex G- 100 followed by ion exchange chromatography on DEAE-cellulose. Also, the effect of pH and temperature on purified xylanase activity was studied.Results: In DEAE- cellulose column chromatography, three protein peaks F-1a, F-1b and F-1c were appeared. Among these peaks, only F-1b showed xylanase activity and the degree of purification attained 63.09 fold. The specific activity and purification fold of the purified xylanase was 87.7U/mg of protein and 17.45, respectively. The enzyme gave maximum activity against xylan as substrate at pH 7.0 and temperature at 60°C. In paper chromatography xylose was detected as the hydrolysis products of oat- spelt xylan by the xylanase at 16 h. These results indicate that xylanase of Bacillus stearothermophilus (ATCC 12980) was endoxylanase.Conclusion: These data includes, optimal pH and temprature suggested that purified xylanase can be suitable for industrial applications.