JOURNAL OF MICROBIAL WORLD
Year:2015 | Volume:8 | Issue:3 (24)|Papers Count:9

Background & Objectives: Infectious Laryngo tracheitis virus (ILTV) is one of the major pathogens causing economic losses in poultry industry. Poultries are the only reservoir of the virus. By now there is no rapid, sensitive and accurate method for detection of this virus. This study was aimed to evaluate and introduce an accurate molecular method by using real-time PCR technique on UL27 proprietary gene of ILTV in order to fast diagnosis of the virus.Materials & Methods: In this experimental study, after preparation of viral sample, the DNA was extracted from virus by using viral nucleic acids extraction kit. Thereafter, the existence of UL27 proprietary gene of the virus was evaluated at first by traditional PCR technique using specific primers and afterwards by real-time PCR technique using specific probe and primers.Results: Observation of expected 96 bp fragment in electrophoresis gel analysis confirmed the presence of UL27 proprietary gene in this viral samples and the results of real-time PCR assay evaluation were also positive in this samples.Conclusion: This study showed that the molecular method of real-time PCR is a suitable method for rapid and accurate diagnosis of ILTV by detection of UL27 proprietary gene.

Background & Objectives: Glander is one of the important zoonotic diseases that is usually caused in solipeds including horse, donkey, mule, zebra and rarely in human. In the recent years, many molecular methods have been developed for the genome study of the Burkholderia mallei. The present study was aimed to optimize VNTR method on the basis of BM140, BM1367, BM2065 and BM2971 loci in order to molecular typing of B. mallei for the first time.Materials & Methods: In this study, B. mallei Razi 325, as a standard strain, was obtained from the microbial archive of the Razi Vaccine and Serum Research Institute. Following DNA extraction and PCR amplification of 4 loci, results of each locus was analysed independently and in different combinations. A special protocol was set in terms of temperature and concentrations of the cotenants (MgCl2 and primers) for each locus.Results: A comparison of the sequences of our isolate with the standard strains indicated the presence of polymorphism in these loci.Conclusion: Achievement of a common PCR protocol, which is able to proceed simultaneously four different reactions in one PCR run, was the primary outcome of this research.

Background & Objectives: Escherichia coli is one of the primary etiologic agents for diarrhoea in neonatal calves, and the maternal immunization is an effective protection for the neonates because of feeding with colostrum. This study was aimed to molecular detection of E. coli K99 and evaluation of the serum antibody titers in laboratory animals.Materials & Methods: This study was experimentally carried out on rat to detect the marker genes. First, a Multiplex PCR was applied to detect the Sta, F41 and K99 pathogenic genes. Following growth of E. coli K99 bacteria into Minca broth, the bacteria were inactivated by 0.4% formaldehyde. The antigen was prepared after washing with PBS and centrifugation. The rats were subcutaneously inoculated with inactivated antigen with 107 and 109 CFU/ml in two groups. The control group was inoculated with a suspension containing all ingredients except for the antigen. Rat was allowed to nurse immediately after injection, and blood samples were taken for serum titration for 8 weeks.Results: An increase in the titer of serum antibody was seen after four weeks, and it continued after seven weeks. The antibody titration of rate was significantly higher in the immunized rat group than in the control group. We found good correlation in two groups. There is a grateful increase in antibody titer in group 2 (received 109 CFU/ml antigen) than in group 1 (received 107 CFU/ml antigen), but decreasing rate in the both groups were the same.Conclusion: These findings indicate that the use of killed antigen with high titer preparation containing sufficient antigen and may provide passive protection in animals. This resulted in by stimulation of immune cell due to high dose antigen.

Background & Objectives: Milk and its products support the growth of infectious germs such as Escherichia coli, the most important agent of food contamination, in special conditions. This study was aimed to optimize the methods of identification of E. coli strains from ice cream based on 16S rDNA.Materials & Methods: In this cross-sectional study, 82 bacterial strain were isolated from 200 ice cream samples collected from different regions of Isfahan. Of these, 48 positive indole strains were isolated. The isolation was carried out based on Iran’s national standards (No 2946) and using chromogenic media on a comparative basis. After numerical analysis, the 16SrRNA was amplified by PCR and the amplified genes were sequenced.Results: We observed that the method used in the national standard is 88% reliable with 12% error. Moreover, the positive indole strain such as Escherichia hermannii, Providencia rettgeri, Klebsiella oxytoca, Morganella morganii showed errors in the final result.Conclusion: We demonstrated that culture media containing chromogenic materials could identify Escherichia coli with a more accurate, simple, quick and inexpensive procedure.

Background & Objectives: Increase in the yield while reducing costs is one of the most important aspects of researches in biotechnology. Considering the amount of bioproducts consumed annually, antibiotics stand at second place, and therefore there has been considerable research to increase their production. This study was aimed to optimize the media used in fermentation process in terms of nitrogen source.Materials & Methods: This study was conducted in Tehran, based on a continuously sampling from the metabolites produced by Saccharopolyspora erythraea. After sporulation, seeding and fermentation, the role of whey powder on several indicators such as pH, biomass production percentage morphological changes in the strain was analyzed. The concentration of the produced erythromycin were examined by spectrophotometry.Results: The results of this study showed the effectiveness of different concentrations of whey powder on fermentation indices. Also, according to the results, the use of soybean meal with whey powder had positive impacts on the amount of erythromycin produced, duration of fermentation and the production costs. The optimized concentration of nitrogen nitrogen for production of this antibody was a combination of 54g/l whey powder with 12g/l soybean meal.Conclusion: Since whey powder is an inexpensive source of nitrogen, it can be used to reduce costs, and increase the yield. Therefore, whey powder can be used as an alternative source of nitrogen in industrial production.

Background & Objectives: Rice mill is one of the mostabundant effluent waste waters worldwide. Due to the high starch and organic compound content, it can be used as alternatives source for ethanol production as an environmental sustainable biofuel. This study was aimed to examine the ethanol production through enzymatic hydrolysis of rice mill and fermentation process by using Aspergillus niger and Saccharomyces cerevisiae yeast.Materials & Methods: In order to optimize the enzymatic hydrolysis process by A. niger, an analysis was performed to determine the effects of different concentrations of effluent with initial starch concentrations (20, 40, 50, 60and80 gl-1) and nitrogen source (NH4NO3, NH4SO4 and NH4CL). The levels of sugar and the produced ethanol were determined by DNS and gas chromatography, respectively.Results: The results showed that the effluents containing a starch concentration of 60gl-1 and (NH4 SO4) had the highest influence on glucose production, 32.27 and 31.84 gl-1 respectively. Also the results of ethanol production through hydrolysis of rice mill, with initial glucose concentration 32. 4gl-1, by saccharomyces cerevisiae showed the maximum amount of ethanol production and yield, 11.51gl-1 of 0.37 g ethanol/g total sugar. The highest cell dry weight and yield were 2.98 g biomass cell and 0.14 g CDW/g total sugar, respectively.Conclusion: Regarding the abundance of rice mill and the yield of ethanol production of this effluent yield, the rice mill can be used as a suitable substrate for the ethanol production.

Background & Objectives: Citric acid is one of the most important organic acid, which is used wildly in different industries, and this demand has been growing every year. This study was aimed to investigate the optimal conditions for the production of citric acid by Aspergillus niger in the presence and absence of SR63.Materials & Methods: In this study, we used different environmental samples such as air, soil, water and leaves to isolate the fungus. Colonies with the ability to growth on czapek dox agar medium were screened. To increase the production efficiency, SR63 was added to fermentation liquid medium. Also, optimising of fermentation condition, temperature of medium and time of fermentation were examined.Result: Overall, 10 colonies were isolated from different environment, which one of them had the best citric acid production ability in compare to the others. The best result was achieved in 30°c for 6 days into a medium with 0.0125g/L SR63 at pH 5.Conclusion: Regarding the results, SR63 could increase the production of citric acid by inhibition of overgrowth of A. niger fungal thread.

Aflatoxin M1 is a metabolite of aflatoxin B1 that is found in milk when lacteal animals are fed with contaminated feedstuff. The presence of aflatoxin M1 causes major disorders in humans, including immunosuppressive, mutagenic, teratogenic and carcinogenic effects. The aim of this study was to investigate the occurrence of aflatoxin M1 in milk of dairy factories of Gilan using ELISA. In this study, totally 100 sample milk were collected in different seasons (5 times in each season) from five dairy factories in Gilan province, randomly. Then samples were examined for the presence of aflatoxin M1 by enzyme-linked immunosorbent assay (ELISA) technique. Totally 11 samples (11%) showed contamination less than the limit level of codex (50 ng/l). Winter samples with an average of 138 ng/l and summer samples with an average 70.92 ng/l had the most and the least amount of contamination, respectively. Factories B and D with yearly average of 135.15 and 60.90 ng/l had the most and the least amount of contamination, respectively. Due to contamination of 89 % of milk samples with high levels of this toxin, and since this contamination can lead to public health problems, it looks necessary a routine serial control of milk and its products. Furthermore, control of foods from mold pollution is the best protection method for prevention of milk from pollution with aflatoxins.