نشریه بیولوژی کاربردی
سال سیزدهم شماره 2 (پیاپی 50، تابستان 1402)

One of the factors causing colorectal cancer is infection with a specific strain of Escherichia coli (E.coli) that has a PKS genomic island with two clbB and clbN genes. One of the ways of human bacterial contamination is to consume vegetables irrigated with water contaminated with bacteria. These two genes cause the activation of the message transmission pathway and the DNA mutation and tumorigenesis by producing the toxin Bactin. The main aim of the present study is to investigate clbB and clbN genes in Escherichia coli isolated from vegetables irrigated with surface water and urban waste.

Vegetables irrigated with surface water, well and urban waste were collected from three regions of Tehran. Their E.coli bacteria were isolated and identified and confirmed. Then, PCR test was performed for clbB and clbN genes of all isolated E.coli bacteria.

The obtained microbial and biochemical results confirmed the E.coli bacteria isolated from the investigated vegetables. The molecular results showed that the highest and lowest frequencies for the samples that simultaneously contained both studied genes were related to vegetables irrigated with urban waste and vegetables irrigated with well water (P≤0.05). This result was almost the same for the vegetables of all three studied regions.

Considering the high frequency of E.coli bacteria isolated from vegetables irrigated with municipal waste and in order to prevent bacterial infection and consequently colorectal cancer, complete disinfection of vegetables and non-irrigation of vegetables in areas with waste are suggested. Keywords: E.coli, clbB, clbN, Vegetables, Urban waste, Surface water.

The purpose of the present study was to investigate the phytoremediation of soils contaminated with heavy metals by microorganisms.

This study was conducted with a review-descriptive method on the studies conducted on herbal treatment.

The results of this study showed that many techniques have been developed to clean soils contaminated with heavy metals. Among these techniques, plant extraction (plant treatment) has been presented as an effective and cheap cleaning method, in which the absorption and collection of pollutants in plant tissues is considered. In this method, by harvesting plants from the soil, the pollutants are removed from the soil. In agricultural lands contaminated with heavy metals, the selection of metal-tolerant crops to remove pollutants from the soil can be a new strategy for land management. A number of cadmium accumulating species that have been reported based on the results of hydroponic and pot tests are species with high biomass, including corn, sunflower and Indian mustard for refining areas contaminated with heavy metals.

Various physical, chemical and biological methods have been suggested for the treatment of areas contaminated with heavy metals and other pollutants, which are mostly costly and uneconomical.

The purpose of the present study is to segment the CT images of the liver with radiology based on the watershed algorithm.

In this study, a semi-automated method for dividing liver tumors using CT scan images has been presented. First, the tumor and liver tissue is determined by the user with point selection. Then, with the help of Abpakhshan method, the three-dimensional morphology of the primary points in the tumor and liver are determined. Then, estimation of tumor and liver tissue labels is done with the method of propagation of dependent constraints. By taking the distance between the obtained labels, the tumor boundary is obtained, and finally, the final boundaries of the tumor are determined by using the edge detector.

Changes in the number of initial points have little effect on the output results. In the CAP method, considering that the data estimation is done using the sampled points and estimates around these points, with any number of initial samples, the CAP method is able to produce the final results, which shows the high power of the CAP method in It is an estimate of the data.

The use of the watershed algorithm improves the segmentation of CT images of the liver with radiology.

The purpose of the present study was to investigate the essential oil of the medicinal plant Thymus vulgaris L. in the production of probiotic dairy products by determining the viability.

Thyme essential oil is used as a flavoring agent in the production of traditional and industrial dairy products (yogurt, buttermilk, and curd). To produce probiotic products and pasteurized dairy products, bacteria are inoculated and different concentrations of thyme essential oil (0, 25, 40, 70, 100 and 130 micrograms/ liter) are added to dairy products. The viability of bacteria in dairy products is checked at specific time intervals (0, 4, 8, 12 and 20 days).

By increasing the concentration of thyme in traditional and industrial dairy products, there is a significant decrease in the logarithm of Lactobacillus and Bifidobacterium bacteria (P<0.05). The highest viability of bacteria was observed with low concentrations of thyme in traditional yogurt, and with moderate amounts of essential oil in buttermilk and traditional curd, within 20 days. The highest viability of bacteria is in yogurt and industrial butter with high concentration and in industrial curd with a decrease in the amount of essential oil. The highest viability of Bifidobacterium bacteria is found with high concentrations of thyme in yogurt, buttermilk and traditional curd (P<0.05), also with low concentrations of thyme in industrial yogurt and buttermilk, and with high concentrations in industrial curd.

In industrial dairy products with thyme, the viability of Bifidobacterium bacteria is longer, and in traditional dairy products, the shelf life of Lactobacillus bacteria is longer.

Purpose: 

Water disinfection is one of the most important stages of water purification in terms of ensuring the health of consumers. Although common methods in drinking water purification can effectively control microbial factors, the formation of disinfection byproducts has made the process of using these methods a challenge. On the other hand, physical and chemical disinfectants are often limited due to their low efficiency, high price and production of toxic products. In the meantime, one of the methods that has been in the spotlight and developed a lot in recent years is the use of electricity to remove biological pollutants from water. Therefore, the aim of the current research is to study and evaluate the efficiency and effectiveness of the method of establishing the current of electricity in removing the coliform bacteria population in the Shahrchai River of Urmia.

Materials and methods:

 The present research, which is descriptive-cross-sectional, started in a period of six months from February 2018 and continued until July 2019. The water sampling process of Shahrchai River in Urmia was carried out from two stations at the entrance of the No. 1 treatment plant and at the entrance of the Golshahr treatment plant, and the samples were transferred to the laboratory within 2 to 4 hours, and the presence of coliform bacteria was studied and measured by the MPN method. Then, in order to perform the electrolysis test, an electrochemical reactor with a voltage of 220 volts consisting of two electrodes made of iron and aluminum was prepared and the electric current was established for 10, 20, 30 and 70 minutes. Next, the data results were analyzed by SPSS version 21 software.

Findings:

 The results show that the efficiency of coliform bacteria population removal depends on the pollutant source, duration, current intensity and type of electrodes. According to the results, the slope of the curve of changes in the amount of microbial contamination of the samples that were subjected to a constant current of 220 volts for 20 minutes showed a significant decrease. So that the microbial load of most samples was reduced by 50%. Therefore, it can be said that the removal efficiency has a direct relationship with the increase in time, and with the increase in the duration of the electric current in the samples, the removal rate of coliform bacteria also increases significantly.

Conclusion:

 According to the results of this research, the use of the process of establishing the current of electricity is suggested as a suitable method with high efficiency and also compatible with the environment in water disinfection.

Increasing antimicrobial resistance in thermonegative bacteria of the Enterobacteriaceae family has become a global problem. Klebsiella pneumoniae is a thermonegative opportunistic pathogen that has been considered in causing a wide range of diseases and antibiotic resistance due to its various resistance mechanisms. In this regard, the aim of the present study is to investigate the presence and role of ompK35 and ompK36 genes in isolates of K. Pneumonia is resistant to several drugs.

96 isolates were collected from patients referred to hospitals in Borujerd city in 2019 and were identified using differential tests. Antibiotic sensitivity test was performed by disk diffusion method and identification of ompK35 and ompK36 genes using PCR.

82.12% of isolates were resistant to ampicillin antibiotic. The most effective antibiotic was gentamicin with resistance rate (38.9%). 28 isolates had multidrug resistance. ompK35 gene in 12.5% of K. pneumoniae and ompK36 gene were observed in 11.45% of clinical isolates.

The results of this study showed that the absence of ompK35 and ompK36 genes plays a role in creating resistance to all kinds of antibiotics and it is necessary to pay attention to this issue in choosing antibiotics to treat and eliminate these isolates. Isolates lacking omk36 were more resistant to the studied antibiotics, especially gentamicin and ciprofloxacin, than isolates lacking ompk35 (P<0.05).