فصلنامه دنیای میکروب ها
سال هشتم شماره 3 (پیاپی 24، پاییز 1394)

Infectious Laryngo tracheitis virus (ILTV) is one of the major pathogens in poultry industry, economically. Poultries are the only reservoir of the virus. This agent causes a relatively prevalent and acute respiratory syndrome in laying Hens and in particular in broiler breeder hens, which reduces egg production and increases mortality in them. Since at present, unfortunately, it does not exist a rapid, sensitive and accurate method for detection of the virus yet, so in this research our aim is to evaluate and introduce an accurate molecular method by using real-time PCR technique, based on UL27 proprietary gene of ILTV, in order to diagnose the virus, rapidly. In this study, after preparation of viral sample, respective DNA was extracted from virus by using viral nucleic acids extraction kit. Then, 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. Obsvervation 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. This study showed that the molecular method of real-time PCR is the proper method for rapid and accurate diagnosis of ILTV by detection of UL27 proprietary gene.

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 in 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. In this study, B. mallei Razi325 (Razi Type Culture Collection RTCC: 2375) as the standard strain was obtained from the microorganisms archive of the Razi Vaccine and Serum Research Institute. The specific primers were designed for the amplification of fragments in the ranges of 450 to 750 base pairs. The comparision of the sequences between theour isolate and standard strains indicated polymorphism in the 4 loci. The major result of this research is developing of the unit PCR protocol for amplification of the fragments.

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. 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. 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. 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.

Food, as a carrier, carries much of the infectious and non-infectious germs in itself which, in some circumstances, underpins the growth of the infectious germs acting either as active transmitters or playing the role of inactive transmitters which, in this case, the agent of infection growing in food is transmitted to man by means of food. Among the most important contaminators of food materials is Escherichia coli being the most abundant optional anaerobic bacteria in the feces. Therefore, it is counted among the hygienic indices. This study was carried out with the aim of a more precise and quicker identification of such organisms. This study, a cross-sectional and descriptive one, was carried out on 82 strains. Out of these numbers, 48 positive indole strains were isolated. The isolation was carried out based on Iran’s national standards and using chromogenic media on a comparative basis. Having conducted numerical analysis and biochemical tests, the researcher carried out thin-layer chromatography and sequencing of 16SrDNA. Considering the presented method in the national standard, the above-mentioned method is 88 percent true and valid bearing a twelve-percent error. In this investigation, the positive indole strain such as Escherichia hermannii, Providencia rettgeri, Klebsiella oxytoca, Morganella morganii developed some errors in the final result. The conducted analyses using culture media containing chromogenic materials showed that the typical Escherichia coli can be identified more accurately since this method is simple, quick and inexpensive.

History and Target: Increasing the yield, while reducing costs, is one of the most important aspects of research in biotechnology. Considering the amount of bio products consumed annually, antibiotics stand at second place, and therefore there has been considerable research to increase their production. This study has been done with the aim of optimizing the fermentation medium compounds of nitrogen source. In this research study with systematic sampling of metabolites produced by Saccharopolyspora erythraea has been done in Tehran. After sporulation, seeding and fermentation, the role of whey powder on indicators such as pH, percentage of biomass produced and morphological changes in the strain has been studied. Using spectrophotometry, the concentration of the produced erythromycin were examined. The results obtained from this study show the effect of different concentrations of whey powder on fermentation indices. Also, according to the results, the use of soybean meal with whey powder had an impact on the amount of erythromycin produced, duration of fermentation and the production costs. Optimizing concentration source of nitrogen has been 54g/l whey powder with 12g/l soybean meal. Since whey powder is an inexpensive source of nitrogen, can reduce costs, and increase the yield. Therefore, whey powder can be an alternative to other sources of nitrogen in industrial production.

Rice mill is one of the most important and abundant effluent waste waters that is generated daily frequency. And due to the high starch and organic matter content can be used as alternatives source for ethanol production as an environmental sustainable biofuel. Therefore, the present study examines the ethanol production of rice mill by enzymatic hydrolysis and fermentation process by using Aspergillus niger and Saccharomyces cerevisiae yeast. In order to optimize the enzymatic hydrolysis process by Aspergillus niger, the effect of different concentrations of effluent with initial starch concentration(20, 40, 50, 60and80) gl-1, and nitrogen source(NH4NO3, NH4SO4andNH4CL)was studied. The results showed that the among different nitrogen source and starch concentration,(NH4 SO4)and 60gl-1, have the highest influence on glucose production with amount 32.27 and 32.4 gl-1 Respectively. Also the results of ethanol production by saccharomyces cerevisiae of rice mill hydrolyzed, with initial glucose concentration 32.84gl-1, showed that the maximum amount of ethanol production and yield were 11.51gl-1of 0.37 g ethanol/g total sugar, respectively. The highest of cell dry weight and yield2.98 g biomass cell and 0.14 g CDW/g total sugar was observed, respectively In general, due to the abundance of rice mill and Also, the yield of ethanol production of this effluent yield, the rice mill can be used as a suitable substrate for ethanol production.

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. 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. 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. Regarding the results, SR63 could increase the production of citric acid by inhibition of overgrowth of A. niger fungal thread.

Aflatoxin M1 is the metabolite of aflatoxin B1 and is found in milk when lacteal animals are fed with contaminated feedstuff. The presence of aflatoxin M1 in milk causes major disorders for humans. It can have 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 in 2012. One hundred sample milk of 5 dairy factories of Gilan were prepared. Five samples were collected randomly from each dairy factory in each season of 2012. Then samples were examined for aflatoxin M1 by enzyme-linked immunosorbent assay (ELISA) technique. Between these 100 milk samples only 11 samples had contamination less than the limit level of codex(50ng/l). Winter samples with an average 138ng/l and summer samples with an average 70.92ng/l had the most and the least amount of contamination respectively. Between these 5 factories, factories (B) and (D) with yearly average of 135.15 and 60.90ng/l had the most and the least amount of contamination, respectively. The results showed that several samples had over the limit contamination. Serious disorders for public health exist from milk consumption. Thus, milk and milk products have to be controlled periodically for aflatoxin M1 contamination. Also, animal feeds should be stored in such a way that they do not become contaminated. Therefore controlling feed mold pollution is the best method for the prevention of milk and its products being polluted by aflatoxins.