فصلنامه زیست فناوری میکروبی
پیاپی 12 (بهار 1391)

Cellulose is the best carbohydrate storage molecule for production of energy in biological systems. Bacterial and Fungal Cellulases play an important role in hydrolysis and use of cellulose. Endoglucanases hydrolyze glycosidic bonds in cellulose and convert it to glucose. The aim of this study was to isolate and identify new strains of the genus Bacillus from the forest soil, with the ability to produce cellulase.Methods of research: in this study was conducted from different 35 soils the forest located in the West of Mazandaran, Iran, and 40 bacterial isolates were collected of this located and Finally were isolated 24 bacterial by using Gram’s iodine test for their ability in production of cellulase on carboxymethyl cellulose (CMC agar). The temperature and time optimization were thereafter performed on the strains. The bacterial species were identified by 16S rDNA sequencing and the approximate molecular weight of the enzyme was determined by protein precipitation and SDS-PAGE. A number of 5 strains belonging to the 5 species including Bacillus Cereus, Bacillus Subtilis, Bacillus Thuringiensis, Bacillus megaterium and Bacillus mycoides, were identified in this study. The highest amounts of the enzyme were produced at 37 °C for 96 hours by all identified species. The highest level of cellulase production belonged to a Bacillus Subtilis strain with 3.8 u/ml. The molecular weight of cellulase isolated from this strain was determined to be about 60 kDa. This study shows the high potential of cellulase production by Bacillus species isolated from the forested areas. These bacteria can directly be used for production of glucose syrup from vegetable fibers a well as in other industries.

Aflatoxins are the most important carcinogenic fungal mycotoxins. Aflatoxin M1 transfer to human by consumption of contaminated milk and other dairy products. Nowdays biological methods are concern as a way to eliminate and reduce mycotoxins. One of this methods is by using specific lactic acid bacteria that have an ability of binding to aflatoxins and inhibition of toxin. Methods of research: Ten Lactobacillus spp. isolated from our local yogurt are examed for their ability to bind to aflatoxin M1 in PBS containing 20 ng/ml for 2 h at 37°C by HPLC method. After that, the best strain was selected and for different hours 0, 4 and 24 were examed for its ability to reduce aflatoxin by HPLC. Then heat treatment were done for cells and after 0,4 and 24 h, HPLC tests were done. The binding abilities of Lactobacillus strains ranged from 47.65% to 51.85%.The Y2L5 strain that isolated from Khik yogurt showed the most binding ability (51.26%).Incubation periods had significant effect on the removal of AFM1 by viable cells ranged from 60.76% to 49/9. Reduction of aflatoxin in different periods for heat-killed cells ranged from 51.6% to 57.65%. The results showed that Iranian native Lactobacillus have good potential to reduce aflatoxin. The different incubation periods for removal of aflatoxin have a significant effects for viable bacterial cells but have no significant effects for dead cells

urinary tracts and Infections are the most prevalent bacterial Infections that are more common in women than men. This study was done with aim of surveying the antibiotic susceptibility and resistance among strains of Escherichia coli that had been isolated from pregnant women in Khoy & Salmas city of West Azerbayjan. This survey was done in section during of the 2010 year from 1900 samples (1100 samples in Khoy and 800 samples in Salmas) and samples have been in a sterile manner and whole pathological tests performed. Evaluation of antibiotic susceptibility had been checked with disk diffusion standard method and results were analyzed. 430 Escherichia coli strains were Identification in Khoy and 317 Escherichia coli strains from salmas. Most resistant to antibiotic Ampicillin were (80.93%) in Khoy and (87.06%) in Salmas and Least resistant to Ceftizoxime were (6.98%) in Khoy and Nitrofurantoin (2.84%) in Salmas. Considering to high prevalence of resistant to antibiotics, fast diagnostic and on time resistant strains to select the best clinical choise and prevent from resistant spread are necessary, To prevent of high risk of infection in kidneys and birth of oaf attention to hygiene points in pregnant women is effective.

Olive and its products are rich in lactic acid bacteria (LAB). Natural fermentation and bitterness process of olive is performed by lactic acid bacteria especially Lactobabacillus and in particular, Lactobacillus plantarum which is one of the probiotic bacteria. Today, Biochemical Approaches and molecular tools such as PCR-based methods are alternative methods commonly used for bacterial identification. The aim of this study was biochemical and molecular identification of Lactobacillus plantarum among lactic acid bacteria isolated from Iranian native olive. In this research, 28 LAB strains isolated from different kinds of Iranian native olive and standard strain of Lactobacillus plantarum were cultured on MRS-agar and biochemical identification tests such as carbohydrate fermentation were performed on each strain. Bacterial DNA extraction was performed by phenol-chloroform method. Specific primers were designed for 16SrDNA+ITS sequence of Lactobacillus plantarum and PCR was performed by touch-up PCR method. In order to more evaluation of the strains and identification the differences between them, the RFLP technique was used and the effects of TaqI and HaeIII enzymes were analyzed on PCR products. From 28 isolated strains, 5 strains were formed strong band by specific primers of Lactobacillus plantarum. One of the PCR products was sent for sequencing and resulting data was confirmed that it was Lactobacillus plantarum. There is no differences between RFLP results on the level of two enzymes, HaeIII and TaqI, but carbohydrate pattern of one strain was slightly different. The result indicated that Lactobacillus plantarum could be isolated from Iranian native olive. According to natural presence of these bacteria, by enrichment and increasing the number of them during fermentation and bitterness stages, the probiotic value of olive could be increased.

Helicobacter pylori (H. pylori) infection is one of the most common gastrointestinal infections worldwide. Infection with H. pylori strains cause in different pathological manifestation and increased oxidative stress leads to a strong inflammatory response in gastric mucosa. There is continuing interest in identifying H. pylori virulence factors that might predict the risk for symptomatic clinical outcomes. The prevalence of cagA gene, protein and the association of serum levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) with oxidative DNA damage were determined. The presence of IgG antibody against CagA protein was determined by using Western blotting technique. The presence of cagA gene was examined by PCR. Oxidative DNA damage status was determined using serum levels of 8-OHdG. Biopsies were considered as H. pylori-positive and negative when both the rapid urease test and bacterial culture gave positive and negative results respectively. H. pylori-positive and cagA-positive was predominant in all clinical outcomes. There was no significant association between prevalence of CagA status and clinical outcomes. The serum levels of 8-OHdG was at a higher level in H. pylori-positive patients. Our results suggest that cagA-positive strains were predominant in patients. However, we found no association between cagA status and clinical outcomes and this virulence factor is not associated with the development of PUD. In addition, serological tests such as the western blotting are helpful in detecting subjects infected with H. pylori strains in PUD and NUD. H. pylori infection may be associated with increased serum 8-OHdG.

The most common serotypes of Salmonella isolated from infected human subjects are Salmonella enteric serovar Enteritidis. The purpose of this study was to isolate Salmonella enteritidis from feces and carcass of different birds using new multiplex PCR method. Sample studied in this research, were collected from carcasses or feces of 9 days old chickens from North and West aviculturesof Iran and alsoFeces or carcasses of different birds such as golden eagles, swan, geese, Flamengo and etc of several Birds breeding and keeping centersin Tehran. The initial separation of the samples from other bacteria, were performed through microbiological methods For accurate identification of species, the genomic DNA from samples isolated and standard strains of Salmonella by Multiplex-PCR using specific primers were examined. Scrutiny of Colonies using common methods of Microbiology showed that 11.69% of all birds examined, are contaminated with salmonella. After compare and review the results of a Polymerase chain reaction, the genus band was observed in all samples, while only 34.21% of them were Salmonella enteritidis confidently. So the remaining samples are likely to infect other species. Review of Electrophoresis bands of the samples tested, and standard strains with desired size, makes it clear that primers used are proprietary. In addition to reducing time to detect Salmonella enteritidis, also has a high accuracy. Based on these results, M PCR method due to using species– specific primers for Salmonella enteritidis is better, faster and more specific compared with bacteriological methods and differentiation of Salmonella enteritidis and other Salmonella species from other Enterobacteriaceae. Therefore, the use of molecular method M PCR will help to control Salmonella infection and prevent the spread of disease among all the birds

Herpes Simplex Virus (HSV) is a member of the herpes virus family, Herpesviridae, which infect humans. There are different methods for detection of this virus like cultural ways which is time consuming, but molecular methods such as PCR are more appropriate for detection of HSV. Although nowadays molecular assays are using in laboratories but different results are achieved because of lack of standard methods which are counted as disadvantageous of molecular methods. For solving this issue in this study, designing of competitive Internal control(IC) through PCR-cloning has been attempted. primers for PCR test were optimized. Besides, the composite primers for IC-HSV were designed then the PCR was optimized. The IC-HSV which amplified, was ligated in pTZ57R plasmid then transformed in E.coli JM107 and was cloned. Specificity and sensitivity of test were determined. PCR amplicon for HSV and IC-HSV with special primers were 454bp and 662bp respectively, so there was a significant different between their size. The appropriate concentration of IC used in each reaction was 50 fg and the sensivity of HSV DNA with IC was between 1 million to 1000 virus particles. Despite of high speed and accuracy of PCR, false positive and negative results which are caused by PCR inhibitors, are the most important problems of this technique that can reduce its efficiency. Using another DNA as an internal control can detect these inhibitors. Indeed, amplification of this DNA shows correct amplification and detection steps.

Infections are a significant cause of morbidity and mortality in neonates, especially in developing countries. The irregular application and inappropriate prescription of antibiotics can lead to development of infection and resistance against bacteria. There for, our aim is the study of antibiotic susceptibility patterns among isolated of infected neonate who’s hospitalized in IMAM HOSSEIN hospital ′NICU for blood and urine infections. This descriptive study was done during seven months from November 2011 to march 2012, on total of 120 blood and urine samples which obtain from NICU in IMAM HOSSEIN hospital. After inoculated blood samples directly on Brain Heart Infusion agar (BHI) and incubation this for 24 hours, with urine samples were cultured on Blood and MacConky agar, for isolation bacteria and utilized phenotypical and biochemical tests for species confirmation and determination of antibiotic susceptibility patterns was done with Kirby-Bauer test. A total of 120 neonate with clinical signs of blood and urine infections, 115 (95.8%) were gram negative bacteria and 5(4.2%) were gram positive bacteria. Klebsiella pneumoniae (39.1%) and Enterobacter cloacae (21.8%) were the most common pathogens and all of five gram positive bacteria was Staphylococcus epidermidis. The gram negative bacteria shown high degree of susceptibility to ciprofloxacin (91%) and gram positive bacteria shown to vancomycin(80%). This result shown that the most contamination in NICU is from gram negative bacteria and ciprofloxacin is the most effective antibiotics for treatment.