نشریه دانش زیستی ایران
سال سیزدهم شماره 1 (بهار 1397)

Antibiotic resistance is documented to be a serious problem that affects the choice of appropriate antibiotic therapy. One of the proposed methods to cope with biofilm bacteria is the use of alternative antibacterial treatments, which include natural antimicrobial substances such as plant essential oils. The aim of this study was to investigate the antimicrobial activity of Zataria multiflora essential oil against biofilms of Staphylococcus aureus clinical isolates. 10 Clinical isolates of S. aureus from various specimens having ability of biofilm formation were screen in this study, On the basis of their ability to attach to polymeric surfaces. Minimum Biofilm inhibitory concentration of Z. multiflora essential oil was estimated on polystyrene microtiter plates. The results indicated that 6 isolates of S. aureus included in this study were able to produce a stable biofilm and Z. multiflora essential oil had antibiofilm activities. Our study identifies that essential oil can be effectively used to control of S. aureus biofilms that Indicating the importance of natural agents as potential antibiofilm and antimicrobial agents.

Despite the Various researches of stem cells in the treatment of diseases, especially heart disease, there is a lot of ambiguity about the act of cells and their secretions. Therefore, the purpose of this study was to evaluate the effect of secretion of bone marrow-derived mesenchymal stem cells on myocardial infarction in male rabbits. After isolating the stem cells from the bone marrow and preparing the conditioned medium, 30 Male rabbits were randomly divided into three groups(n=10). Myocardial Infarction was induction in two groups and in a group conditioned medium was injected into the hearts of rabbits. Then in the first, fourth and eighth weeks, the heart parameters (HF, EF) were measured by echocardiography and then TNF-α factor was measured in the serum. Heart tissue was removed and the level of angiogenesis and fibrosis were investigated. In the treated group with conditioned medium, the heart parameters (HF, EF) and angiogenesis increased significantly and decrease the level of TNF-α factor and fibrosis was significant in comparison with the Myocardial Infarction group (P<0.05). Since the cardiac tissue and its function improved in this research, it seems that the secretion of bone marrow-derived mesenchymal stem cells have therapeutic effects on myocardial infarction.

Date have a significant contribution in the food basket of humans in many countries of the world, including Iran and it’s one of the most valuable foods that make up most of it sugar. Water, cellulose, pectin, ash and minerals are other ingredients of the date composition. So dates are one of the most important sources of mineral salts in a balanced diet. For this reason, the presence of toxic pollutants in dates causes many diseases in humans. Therefore, monitoring the quality and health of this natural product is essential. For this purpose, in 2016, a study was conducted to investigate the amount of heavy metals (lead, cadmium, copper and zinc) in consumer dates in Ahwaz. This experiment was carried out 3 replications and in the form of the completely randomized design (CRD). Statistical analyses were performed using the MSTST-C statistical package and means were compared with Duncan test at 5 percent level. Experiments related to the estimation of the amount of the metals were carried out using atomic absorption of furnace to detect heavy metals (Cadmium, lead) and atomic absorption of flame for the detection of heavy metals (Zinc and Copper). The results of this study showed that the average of total concentration of Cd, Pb, Cu, and Zn in date samples were equal to 0.713±1.96 ,3.53± 2.74, 0.136± 0.072 and 4.433±0.324. The results of analysis of variance indicated that there was a significant difference between the samples in terms of heavy metals (lead, Cadmium, Zinc and Copper) at 1% level. The results showed that the Dairy date had the highest amount of lead (8 µg. g-1) and Cadmium (33.6 µg. g-1), Zahedi date had the highest copper (0.31 µg. g-1) and Gentar date had the highest Zinc content (29.1 µg. g-1), indicating a low level of these heavy metals in comparison with the date standard, which indicated a high degree of confidence in the determination of their health and safety for consumption.

Clostridium difficile is the most important spore forming, gram positive, anaerobic bacillus which is known as prevalent factor of hospital diarrhea and causative agent of pseudomembrane colitis. When the natural microflora of the intestine is disturbed by risk factors, such as antibiotics, chemotherapy, etc., Clostridium Diphysil can be proliferated and cause the disease. The important virolence factors of this bacteria is A and B toxins. the clinical demonstration of Clostridium difficile infection range from asymptomatic colonization, to sever diarrhea, pseudo membranous colitis, toxic megacolon and death. The purpose of this study was to extract Clostridium difficile cells from faecal samples and develop a routine diagnostic laboratory method using qPCR to identify this bacteria with high sensitivity and accuracy. 100 clinical samples were collected within 6 months from patients being treated at Ayyatollah Taleghani education and treatment medical center. a standard strain was obtained from Pasteur Institue micobial seed bank. For determination of the specificity of the method being developed, the DNA of Escherichia coli, Shigella, Shigelladysenteriae, Salmonella typhi, Yersinia Entrocolitica were extracted and analyzed along with a primer designed for Toxin A in Clostridium difficile using q PCR. After optimization of the test conditions, 100 clinical samples were evaluated. Among the samples, 9 of them were (9%) positive. For evaluation of the sensitiviy of the test, the obtained DNA from the bacteria was diluted, and further analyzed using qPCR. To determine the specificity of the test, the genome of diarrhea causing bacteria were used which lead to positive results only from the genome of Clostridium difficile. Based on the obtained results, the sensitivity and precision of qPCR in rapid detection of 100 pg of DNA was determined.

Superparamagnetic iron oxide nanoparticles (SPIONs) are an Important advancement in the field of nanotechnology. They expand the possibilities of noninvasive analysis for tracking of cells and have many useful properties, making them potential candidates for numerous applications in medicine. However, the possibility of toxicity in cells is reported by these nanoparticles. The goal of this study was to find a concentration of SPIONs that cant induce intracellular levels of Reactive Oxygen Species. For this purpose for the first time amniotic membrane stem cells were incubated with different concentrations of SPIONs coated with polyethylene glycol (PEG). Then intracellular levels of Reactive Oxygen Species was measured By probe Rhodamine 123 . Our results demonstrate that there was no significant generators of Reactive Oxygen Species in cells in concentration range of 0-100 μg/mL of spions. However, at concentrations higher than 100 μg / ml, the production of Reactive Oxygen Species increased. According to the results nanoparticles used in this study at concentrations ≤100 μg/mL are suitable for tracking of this cells.

Cryptosporidiosis is a wide spread cause of diarrhea disease of humans and many mammals caused by infection of intestinal epithelial cells with protozoan agent Cryptosporidium. This study was designed to evaluate epidemiological prevalence of the human cryptosporidiosis of Varamin area in 2012-2013. The study population comprised 930 human with diarrhea. During the 12 months a total of 930 human fecal samples were collected and one portion of each sample was stored at 4°C and the remaining was stored in potassium dichromate solution until processing. Cryptosporidium oocysts were identified by using formalin detergent concentration and modified Ziehl-Neelsen staining method. The infection rate was  %5.17 in age group 1-10 years , %3.74 in 11-20 years , %4.14 in 21-30 years , %3.41 in 31-40 years, %2.43 in 41-50 years and %1.28 in 51-60 years. In this study a correlation was observed between cryptosporidial infection with human age that a statistically significant difference found between age and prevalence of crytosporidiosis. Because Cryptosporidiosis is a zoonosis infection, the prevalence of Cryptosporidiosis detected in this study suggested that the close interaction between livestock and human in Varamin rural areas may play a role in crytosporidiosis transmission to human.