نشریه بیولوژی کاربردی
سال سیزدهم شماره 1 (پیاپی 49، بهار 1402)

Enzymes act as natural catalysts in biological reactions. But they have limitations such as lack of thermal stability, short life span and their lack of stability in the organic environment. Therefore, scientists have tried to improve the performance of enzymes in different ways, including nanotechnology. Therefore, the aim of the current study is to produce enzyme nanoparticles and evaluate some of their properties, which are being worked on due to the importance of urease in medicine, agriculture and industry.

In this research, increasing the stability of urease was done based on the production of enzyme nanoparticles by desolvation method. Synthesized nanoparticles were examined using Fourier Transform Infrared Spectroscopy (FTIR), Visible-Ultraviolet Spectroscopy (UV-Vis) and Scanning Electron Microscope (SEM). Also, the general and specific activities of free and nano enzymes were measured and compared at 37°C. In addition, free and nano enzymes were incubated for 10 minutes at temperatures between 30 and 70°C and then their activity was measured.

The results of spectroscopy and scanning electron microscopy confirmed the formation of urease nanoparticles. Also, the activity determination results showed that with the formation of enzyme nanoparticles, despite the decrease in the total activity of the enzyme, its specific activity increased by 43.46%. The optimal activity temperature of total free urease was 50°C and urease nanoparticles was 60°C.After 10 minutes of incubation at 70°C, the free and nano enzymes retained 2% and 32% of their activity, respectively, which indicates an increase in thermal stability in this method.

By preparing enzyme nanoparticles, it is possible to improve their activity and application in the industry.

Fast and correct diagnosis of the disease is very important in many cases. In X-ray medical imaging, the doctor treats the patient without accessing the inside of the body's organs. Therefore, the standard conditions must be met so that the benefits of using X-rays are greater than its disadvantages. Since the presence of medical personnel in imaging centers is now a necessity, they are therefore vulnerable due to constant exposure to the dangers of X-rays. Assessing the level of risk requires the definition of effective parameters that are associated with uncertainty. In this regard, the aim of the current research is to evaluate the harm of X-rays in diagnosis and treatment in medicine with the help of fuzzy logic. In this research, by using the fuzzy method, and with the help of graphic tools of MATLAB software, and determining four input parameters and one suitable output parameter, and by determining the rules by an expert and the Mamdani fuzzy inference system, the harms of X-rays for the referring person and The treatment panel was checked for imaging. Examining the data of six selected medical imaging centers in different cities of Iran showed that all these centers are in the medium range of vulnerability to the dangers of X-ray radiation. It seems that the Ministry of Health and Medicine should take more, continuous and serious care regarding safety and protection in medical centers. Safety points must be fully observed, otherwise, in the long run, the treatment staff will face problems with X-ray radiation.

Considering the importance of potato in the economy and human nutrition, the need to produce healthy seeds through tissue culture in order to increase the quality of the tuber and ultimately maintain the yield of the product is noticeable. In this regard, the aim of the present study is to evaluate the morphological and biochemical traits in the seedlings of four early and late potato cultivars under in vitro conditions. Four commercial varieties of potato were cultivated as single-node microspecimens in MS culture medium without any plant growth regulators. Seedlings grew after 5 weeks. Seedlings were evaluated in terms of morphological traits (number of seedlings produced from one seedling, stem length, number of branches, nodes, roots and micro-gland) as well as biochemical traits (chlorophyll a, b, carotenoid, anthocyanin, catalase enzyme activity and polyphenol oxidase enzyme activity). In morphological traits, late cultivar Satina, number of seedlings and stem length, and early cultivar Sante showed more roots than other cultivars. In the study of biochemical traits, the late cultivar Agria was superior to other cultivars in terms of the amount of pigments and catalase enzyme. In the same vegetative conditions, different cultivars have different potential in vegetative and biochemical traits. The growth pattern of different genotypes is determined by the synthesis of food and different levels of internal hormones and the balance between them, and as a result, they give different responses to the conditions of the culture environment. The present study showed that in the same vegetative conditions, the early cultivars of Satina in terms of vegetative traits and Agria in terms of the amount of pigments can be selected for mass cultivation.

Biosurfactants have wide applications in the microbiology of food and oil. The aim of this research was to investigate the production of stable biosurfactant in high temperature and salinity from yeasts isolated from oil-contaminated soil. Bushnell Haas culture medium was used to screen biosurfactant producing yeasts. The presence of biosurfactant was evaluated using oil dispersion and surface tension reduction tests. The best biosurfactant producing strain of Radotrulla mucilaginosawas named GBMEIAUF1 and its 5.8s-rDNA gene sequence was registered inthe NCBI gene bank under accession number CBS11162. The results of thin layer chromatography and Fourier transform infrared spectroscopy confirmed that the extracted biosurfactant was sophorolipid with significant surface activity. Purified sophorolipid decreased the surface tension of water from 72 mN/m to 1.29 mN/m. The highest emulsification index, E24%, the extracted biosurfactant was 53% and retained 63.71 to 58.09% of its initial activity at 80 to 120 degrees Celsius. This biosurfactant also retained 82.67 and 89.41% of its initial activity at pH 10.5, and 12, 59.66% of its initial activity at 10% salinity. This research is the first report of sophorolipid production by the yeast Redotrula mucilaginosa.Due to its thermal stability and high pH and salinity tolerance, sophorolipid produced by Redotrula mucilaginosa can be strongly recommended as an effective emulsifying agent for application in microbial enhanced oil extraction programs as well as food industry.

Cervical cancer is an important cause of female mortality worldwide. The results obtained so far indicate the involvement of bioactive peptides in cancer treatment. In this regard, the aim of the present study is to investigate the anticancer properties of HL-7 peptide through changes in Fas, caspase 8 and caspase 3 geneexpression. In this study, the viability of cervical cancer cells treated with HL-7 peptide at two concentrations of 45 and 60 μM at two times of 12 and 24 hours was investigated using MTT assay. Also, the expression of Fas, caspase 8 and caspase 3 genes was measured at mRNA and protein levels, respectively, using Real-Time PCR and Western Blot methods. Finally, the activity level of caspase 3 and caspase 8 was checked through ELISA test. The results showed that the viability of cancer cells treated with HL-7 peptide decreased in a dose- and time-dependent manner (p<0.05). By increasing the concentration of HL-7 peptide from 45 to 60 μM, significantly, the expression of Fas, caspase 8 and 3 genes increased in mRNA and protein levels (p<0.05). The results of the ELISA test showed that the activity of caspase 8 and caspase 3 significantly increased in Hela cancer cells treated with HL-7 peptide compared to untreated cancer cells (p<0.05). It seems that HL-7 peptide is able to eliminate cervical cancer cells by regulating the expression of genes involved in the extrinsic apoptosis signaling pathway. At the same time, more studies on molecular targets are suggested to confirm the anticancer properties of HL-7 peptide.

Mashhad is the most important city in the country due to its tourist and pilgrimage attractions, and ensuring the safety of its drinking water is very important, especially for travelers. The aim of the present study was to investigate the microbial quality of drinking water in Mashhad

This is a field research and a cross-sectional study. Sampling locations were determined by systematic sampling method. The drinking water of 15 selected stations was studied during 10 months from February 2019 to the end of December 2011. Each station was sampled 4 times in 4 different seasons. The samples were studied in three parts of bacterial, fungal and protozoan contamination assessment, according to existing standards.

The microbial quality of Mashhad's drinking water supply sources was very favorable in terms of total and faecal coliform contamination and was in line with the national standard. From a total of 220 fungal colonies grown, 7 different genera of fungi were identified. In general, the average CFU of isolated fungi for samplesper 100 ml of water was 6.2.The most common isolated fungus was Aspergillus (40.45%) and the least isolated colony was related to Fusarium (1.3%). No samples of protozoans or cysts related to protozoans were observed in any station.

According to the guidelines of the World Health Organization in 2006 for evaluating the microbial health of water, the drinking water quality of Mashhad was in accordance with the national standard. Mashhad's drinking water also contains various fungi. Therefore, it is suggested that in the regular monitoring of the urban water system in terms of microbial contamination, fungi should also be investigated as one of the important microorganisms. Regarding contamination with protozoa, no contamination was observed. In order to maintain the desirability of drinking water in Mashhad city, it is suggested that the water and sewage company continuously monitor the quality of drinking water sources.