مجله میکروبیولوژی کاربردی در صنایع غذایی
سال هفتم شماره 3 (پاییز 1400)

Tadays, probiotic bacteria such as lactobacillus known as a major contributor to many diseases, including cancer. The aim of this study was to compare the microcystin poison and probiotic bacteria of Lactobacillus paracasei separately and simultaneously in the treatment of A549 cancer cell lineage of lung adenocarcinoma. In this experimental study, the extract of Lactobacillus paracaeoetica L. cells was prepared at different concentrations. Then a sample of microcystin was prepared. The effects of cytotoxicity of cell and bacterial cell extract on 549A cancer cell line were investigated using MTT method for 24 hours. Also, the expression of Bax and Bcl2 apoptotic genes in A549 cell line was investigated using Real Time PCR. The results showed that the expression of Bax gene expression in microcystin and microcystin treatments plus Lactobacillus paracaea cultivar was higher than reference gene expression (GAPDH) (P <0.001), which increased expression to 6 / 2 and 4.54 times than reference gene expression. Meanwhile, expression of Bax gene was not (P <0.001) significant in cell-to-cell treatment with bacterial extract despite a one-time increase. Also, the expression of Bcl-2 gene expression in all treatments was reduced compared to reference gene expression, so that in microcystin treatment, bacterial culture extracts, and the combination of both substances, expression rates were 2.2, 1.27 and 2.7, Three times the reduction showed that reduction of Bcl-2 gene expression in microcystin and bacterial culture extracts was significantly decreased (P <0.001). It can be concluded that the extract of Lactobacillus paracasie alone cannot induce apoptosis in the treated cells, but its combination with the microcystin toxin induces this process.

Lactic acid bacteria have been used as a starter culture to produce fermented dairy products. Identifying and studying the technological and antimicrobial properties of these bacteria can enable their industrial applications. The aim of this study was to investigate the technological and antimicrobial characteristics of Lactobacillus brevis isolated from Khikki cheese. For this purpose, after Gram-staining and catalase test, molecular identification of the desired strain was performed using FYM27 and R1492 universal primers. Various technological characteristics of this strain such as exopolysaccharide production, proteolytic activity, lipolytic activity, acid production, survival under refrigerator conditions and its autolytic activity were examined. The antimicrobial activity was measured using “Lawn on the spot” method on food borne pathogens. The results showed that the strain belongs to L. brevis gp104. This strain also had ability to produce exopolysaccharide as a secondary metabolite; although it did not show proteolytic and lipolytic activity. Lactobacillus brevis reached pH = 4.6 at 15 °C after 72 h. This time was 48 and 24 h for 24 and 37 °C, respectively. The results showed that on the seventh day of its storage in refrigerator, the survival of the strain was approximately equal to the initial inoculated amount, but after 14 days, 1.5 Log CFU/ml and after 21 days, about 2 Log CFU/ml decreased in its number. In addition, the autolytic activity of Lactobacillus brevis was calculated to be 53%. The inhibition zone diameter for Enterobacter aerogenes, Salmonella typhi, Staphylococcus epidermidis and Listeria innocua was 11.30, 10.10, 22.40 and 19.50 mm, respectively. Due to the favorable technological potential of L. brevis, this strain could be used in the production of probiotic products as well as adjunct culture in fermented products.

Nowadays, the need for new strategies to control the activities of resistant bacteria is felt more than ever. In this regard, a very promising approach is the use of nanomaterials science and the knowledge that is expanding in the field of Nano synthesis biosynthesis should be considered as a global strategy. The aim of this study was to evaluate the antibacterial properties of biosynthetic copper oxide nanoparticles on the expression of the AmpC gene in Pseudomonas aeruginosa. 10 samples of P. aeruginosa were collected from clinical centers of Khorramabad city in 1399 and identified based on biochemical tests. After treatment of MDR strains with the minimum inhibitory concentration of copper oxide nanoparticles, the expression level of the AmpC gene was evaluated using real-time PCR. After applying the effect of biosynthetic copper oxide nanoparticles on AmpC gene expression and calculations performed by MIC and ANOVA one-Tukey statistical analysis test, it was found that copper oxide nanoparticles have an inhibitory effect on the expression of AmpC genes of P. aeruginosa samples. The objectives of this study focused on the use of nanotechnology as a new tool to address current challenges in the treatment of infectious diseases and antibiotic resistance. Therefore, for safer use of this nascent technology, the need for clinical trials and further research at the level of molecular biology is recommended.

Celiac Patients should follow a strict gluten-free diet during the life, which causes many nutritional deficiencies. The aim of this study was to produce a functional quinoa-based gluten-free cake mix for glutensensitive people. For this purpose all components were added in powder form. Quinoa flour was used at three levels of 25, 27.5 and 30%, inulin was used as prebiotic and fat substitute at three levels of 2.4, 3.2 and 4% and the probiotic bacteria Bacillus coagulans was used (2×1011 cfu/g) in quinoa treatments. A commercial cake mix was used as a control sample. Appearance of cake mixes and nutritional properties (protein, fat, carbohydrates, ash, fiber and calories) of quinoa cakes were compared with control. The textural properties of cakes (adhesion, springness, cohesion, porosity, browning index and general acceptance) were examined and compared. Data analysis showed that some nutritional parameters including minerals, protein and crude fiber increased significantly in quinoa treatments and the fat, carbohydrate and calorie content was lower than the control sample. The trend of moisture reduction was slower than the control sample during four days refrigeration. With increasing the amount of quinoa, adhesion, cohesion, porosity and springiness decreased significantly and the browning index of cakes increased. The number of bacteria on the fourth day of refrigeration was sufficient to be considered as a probiotic product (4.5×107 cfu/g). The overall acceptance score of the treatment number 2 (T2) (containing 27.5% quinoa and 3.2 inulin) was not significantly different from the control sample. The composition of amino acids and fatty acids of T2 were more beneficient than control sample and its peroxide index was lower than control.

The aim of this study was to evaluate the effect of fatty foods on colon tissue and also to evaluate the effects and function of Lactobacillus plantarum on colorectal cancer in comparison with chemotherapy drugs. 25 rats prepared from Pasteur Institute of Iran were divided into 5 groups: rats in negative control group received water and normal food and in fatty food group, the rats consumed only high-fat food. In the other groups, intestinal cancer was induced by adding Sodium dextran sulfate to drinking water, injection of azoxymethane and consumption of fatty foods. The tumor group did not receive treatment after cancer. The Lactobacillus plantarum group was gavaged with this microorganism and the chemotherapy group received 5-fluorouracil. The levels of interferon-gamma, interleukin-4 and transforming growth factor-beta cytokines were evaluated in rat blood serum. Pathological examination of intestinal tissue was assessed by hematoxylineosin staining. The present study showed that the consumption of fatty foods causes polyps in the rat intestine and regular consumption of Lactobacillus plantarum increases interferon-gamma and interleukin-4 and decreases transforming growth factor-beta, the same as chemotherapy drugs. Also, the pathological examination showed apoptosis in cancer cells in the groups receiving lactobacillus plantarum and the chemotherapy drug. Fat consumption is effective in the development of gastrointestinal diseases such as adenomas and intestinal polyps and intaking appropriate doses of probiotics such as Lactobacillus plantarum can improve colon cancer.

Gamma aminobutyric acid (GABA) is a bioactive molecule with various physiological functions in the body that by inhibiting neuronal stimulation and the Prevent of delivery messages containing stressful compounds cause relaxation and has an effective role in the treatment of various diseases. Therefore, the aim of this study was to investigate the effect of two independent variables including pH (4-4.6), glutamic acid (300-600 ppm) on survival and GABA production by Lactobacillus brevis and general acceptance of yogurt. According to the results, with increasing pH and glutamic acid, the survival of probiotic bacteria, the amount of produced GABA and general acceptance significantly (p≤0.05) increased. Simultaneous optimization results (viability of Lactobacillus brevis, GABA content and general acceptance) showed the maximum survival rate (7.7278 log cfu/g), GABA content (342.9444 ppm) and general acceptability score (4.8367) after 28 days of storage, with 98.406% desirability in probiotic yogurt inoculated with Lactobacillus brevis containing 600 ppm glutamic acid and pH 4.60 was observed. The results showed that by using GABA producing probiotic bacteria in yogurt formulation, probiotic yogurt can be produced with desirable nutritional properties and take a positive step towards producing functional products and promoting consumer health.