saeid hosseinzadeh

Considering the broad spectrum of using nanoparticles in food coatings as a potent antimicrobial agent and their possible cytotoxic effects and accidental consumption of these toxic materials, this study was performed. The present study aimed to investigate the cytotoxicity of chitosan and nano-chitosan in vitro.

This cross-sectional study was conducted in 2019 in the Laboratory of the Department of Food Hygiene and Public Health, School of Veterinary Medicine, Shiraz University, Shiraz, Iran. The XRD and FITR techniques were employed to study the characteristics of these nanoparticles. Moreover, two cell lines, HT-29 and Vero, were used to study the cytotoxic effects of chitosan and nano-chitosan by MTT assay, acridine orange, and ethidium bromide staining. One-way ANOVA and independent t-test were used to analyze the collected data with the help of SPSS software (version 19).

Based on the obtained findings, the maximum values of XRD at the angle of θ2 were observed at 20°. The highest peak appeared at 1530 cm-1, which was associated with tensile vibration of N-P-N. The spectrum diagram of chitosan due to the tensile vibration of synthetic nanochitosan of N-H bound appeared at 1646 cm-1. The results showed a proportional increase in the cytotoxicity with time and concentration of nanoparticles in the cells.

Since by increase in time and concentration of nanoparticles, toxicity was observed in cells; therefore, the time and concentration of chitosan nanoparticles are important in causing cytotoxicity. Considering the toxic effects of these nanocomposites on cancer cells, they can be used in cancer treatment, which requires further studies.

High levels of resistin are associated with metabolic diseases and their complications, including hypertension. The paraventricular nucleus (PVN) is also involved in metabolic disorders and cardiovascular diseases, such as hypertension. Therefore, this study aimed to study cardiovascular (CV) responses evoked by the injection of resistin into the lateral ventricle (LV) and PVN and determine the mechanism of these responses in the rostral ventrolateral medulla (RVLM).

Arterial pressure (AP) and heart rate (HR) were evaluated in urethane-anesthetized male rats (1.4 g/kg intraperitoneally) before and after all injections. This study was carried out in two stages. Resistin was injected into LV at the first stage, and AP and HR were evaluated. After that, the paraventricular, supraoptic, and dorsomedial nuclei of the hypothalamus were chosen to evaluate the gene expression of c-Fos. Afterward, resistin was injected into PVN, and cardiovascular responses were monitored. Then to detect possible neural mechanisms of resistin action, agonists or antagonists of glutamatergic, GABAergic, cholinergic, and aminergic transmissions were injected into RVLM. 

Resistin injection into LV or PVN could increase AP and HR compared to the control group and before injection. Resistin injection into LV also increases the activity of RVLM, paraventricular, supraoptic, and dorsomedial areas. Moreover, the CV reflex created by the administration of resistin in PVN is probably mediated by glutamatergic transmission within RVLM. 

It can be concluded that hypothalamic nuclei, including paraventricular, are important central areas for resistin actions, and glutamatergic transmission in RVLM may be one of the therapeutic targets for high AP in obese people or with metabolic syndrome.

Since diminished hippocampal insulin signaling leads to memory impairment, insulin resistance and hyperinsulinemia are probably associated with Alzheimer’s disease (AD). The effect of intracerebroventricular injection of insulin (Ins) and oral cinnamon extract (Cinn) on glucose transporter (GLUT) 1, 3, and 4 gene expressions in the hippocampus and spatial memory in a streptozotocin (STZ)-induced AD rat model was investigated in the present study.

Fifty-six adult male Sprague-Dawley rats (280±20 g) were allocated into eight distinct groups (n=7) of five controls (negative, Ins, Cinn, Ins+Cinn, and STZs) and three treatments (STZ+ Ins, STZ+ Cinn, and STZ+ Ins + Cinn). Single dose STZ 4  mg/kg (icv), Cinn at a dose of 200 mg/ kg (orally for 14 days), and Ins 5 mIU/5 µl (icv for 14 days) were administered in the defined groups. To evaluate the behavioral performance the animals were subjected to the Morris Water Maze (MWM) test. The level of mRNA expression of GLUTs was evaluated by the Real time-PCR method. 

In the STZ+Cinn+Ins group, the performance of animals in the MWM test was improved and the over-expression of GLUTs genes in hippocampal tissue was observed. The results of Ins and Cinn synergist treatment groups revealed improvement in the behavioral tests and gene expression compared with Ins and Cinn treatment groups (P<0.001).

Administration of Ins and Cinn has a positive effect on the function of the AD rat model. To clarify the effect of Ins and Cinn extract on the GLUTs investigated in this study, it is essential to evaluate their influence on the protein levels.

Mastitis is a global disease occurring in dairy cows, causing notable economic losses. Extensive use of antibiotics could allow the emergence of mobile antimicrobial resistance genes in mastitis-causing pathogens. This study aimed to investigate the prevalence and characterization of colistin resistance genes in E. coli recovered from bovine mastitic milk. A total of 74 E. coli isolates were investigated for antimicrobial resistance. The presence of mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5 plasmid-mediated resistance genes, as the most crucial contributors to resistance to colistin, was examined by Multiplex PCR. Antimicrobial susceptibility patterns of all isolates to the seven most common antibiotics applied in dairy herds, including colistin, ceftriaxone, ampicillin, tetracycline, gentamicin, enrofloxacin, and trimethoprim-sulfamethoxazole were determined by the DD test. Among all samples, 70 isolates (94.6%) were resistant to colistin. In the MIC test, all isolates were also resistant to colistin, which was in agreement with the DD test. None of the E. coli isolates carried plasmid-mediated colistin resistance mcr-1 to 5 genes in Multiplex PCR. Despite the important role of food-producing animals in the transfer of antibiotic resistance, mastitis-causing E. coli isolates were not the source of mcr 1 to 5 genes in this study. The present research showed a high level of phenotypic resistance to colistin, while there was no agreement with their genotypic resistance. Consumption of polymyxins in dairy calves and the probable existence of other more effective resistance genes could be the reason for this high rate of phenotypic resistance.

In this study, cytotoxic effects of silver-chitosan nanocomposites with aqueous sodium hydroxide solution (SCNC-ASHS) and aqueous acetic acid solution (SCNC-AAAS) were evaluated in vitro. The morphology of the synthesized nanoparticles was characterized by Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Their cytotoxicities were then evaluated using MTT in concentrations of 1.56 to 400 µg/ml, and Acridine orange/Ethidium bromide (AO/EB) staining test after 24 h and 48 h. Results showed that the highest cytotoxicity was at 400 µg/ml concentration at which SCNC-ASHS respectively showed 80.57% and 84.37% toxicity on Vero and HT-29 cells after 24 h, and 82.20% and 84.84% after 48 h. While, the cytotoxicities for SCNC-AAAS on Vero and HT-29 cell lines were respectively 80.63% and 87.64% after 24 h, and 83.60% and 87.44% after 48 h. The most toxicity on HT-29 cells belonged to SCNC-AAAS with IC50 of 40.4 µg/ml. In the staining test, SCNC-AAAS revealed 41.84% HT-29 cell viability at 25 µg/ml concentration and 37.51% Vero cell viability at 6.25 µg/ml concentration. Generally, by increasing both SCNCs concentrations, the cell viabilities were decreased, and early and late apoptosis and necrosis were increased in AO/AE test. In conclusion, types of nanoparticles, synthesis methods, and different cell lines play considerable roles in inducing cytotoxicity. According to the higher significant cytotoxicity effects of both SCNCs on colon cancerous cells (HT-29) than normal cells (Vero) (p<0.05), it seems that they have anticancer effects; of those SCNC-AAAS displayed the higher effect with the IC50 of 4.4 µg/ml on HT-29 cells.

CGRP and rCT are involved in descending pain control areas. This study aimed to evaluate the effect of intracerebroventricular administration (ICV) of CGRP and rCT on mRNA expression of CGRP and rCT peptides in the Periaqueductal Gray Area (PAG) of the diabetic rats in the formalin test.

This study investigated 24 male Sprague-Dawley rats in four groups (n=6). To induce diabetes, streptozotocin at a dose of 45 mg/kg was used intraperitoneally. CGRP or rCT peptides at a dose of 1.5 nmol with a volume of 5 μl were ICV injected daily for seven days. Pain-related behaviors were recorded in the formalin test for up to 60 min in the study groups. The PAG was then removed to assess the changes made in the mRNA expression of the CGRP and rCT.

ICV injection of CGRP or rCT in diabetic rats reduced pain in the acute and middle phases of the formalin test. In addition, ICV administration of CGRP increased CGRP mRNA expression in the PAG. However, ICV administration of rCT increased the mRNA expression of both CGRP and rCT peptides after seven days in the PAG.

ICV injection of CGRP and rCT peptides reduced the pain of formalin injection in rats in the experimental model of streptozotocin-induced diabetes mellitus, possibly by altering the mRNA expression of both peptides.

The antibacterial and antifungal effects of pomegranates peel and seeds are associated with the presence of phenolic compounds (flavonoids and tannin). These compounds accumulate in the skin and pomegranate juice and account for 92% of the antioxidant activity of pomegranates (Abid et al. 2017). Total tannins for pomegranate peel and pulp were reported to be 9.73 and 0.66%, respectively (Delavare et al. 2014). The different species of pomegranate have antibacterial and antifungal properties that can influence on a wide range of microorganisms (Carlton et al. 2000). Phenolic compounds in plants and foods by changing the gut microbial population can increase the amount of useful bacteria and reduce harmful bacteria (Katiyar 2002). It has been found that intestinal microflora plays a critical role in the health of the digestive tract and is dependent on the ration as the final source for metabolism of organic compounds. (Choct et al. 1996). To our knowledge, the effects of pomegranate by-products have been investigated on livestock and rumen function, however their effects on the intestinal microflora in ruminants have not been addressed. Therefore, due to the high concentration of tannins and phenolic compounds in the pomegranate by-products and their effect on intestinal microflora, the aim of this study was to investigate the effects of pomegranate pomace silage and pomegranate air-dried pomace on intestinal microflora in Mehraban fattening lambs.

Nine male lamb of Mehraban breed (mean weight of 27.03±3.5 kg and mean age of 187.8±1.4 d), were fed on three iso-nitrogenous and iso-caloric diets. Diets were balanced according to NRC (2007) recommendation including control diet, diet contain 27% pomegranate pulp silage (mixture of seed and pulp at equal ratio) and diet contain 31% air-dried pomegranate seed pulp. All three diets were fed for 60 d after 3 weeks for adaptation in individual pens with free access to salts lick and water. At the end of experiment all lambs were slaughtered and after than for enumeration of intestinal fluoromicrobes, one gram freshly digested specimens of ileum and cecum were collected. Samples were spread on the surface of agar medium. Colonies were counted by ophthalmic count and bacterial count was calculated as CFU/g (number of colonies per gram). The MRS agar and MacConkey (MC) medium were used for identification and enumeration of Lactobacillus spp and Escherichia coli respectively. All samples were incubated at 37ºC for 24 hours. All colonies were enumerated and recorded as CFU/g of culture suspension. For confirmation of Escherichia coli detection on MacConkey agar medium, polymerase change reaction (PCR) was conducted as DNA extraction using commercial kit (Bioneer, Sout Korea), polymerase change reactions, and electrophoresis of PCR products. Detection of molecular bacteria was done using the primers of 23S rRNA gene PCR. The PCR process was initial denaturation at 94 ºC for 2 minutes and totally 35 cycles, denaturation at 94 ºC for 45 seconds, and extension at 72 ºC for 2 minutes. All data was analyzed as a complete randomized design using SPSS software. Significant difference for means was considered at 0.05 level of differences.

The results of this study showed that in MRS medium either in ilium or cecum, the number of lactobacillus bacteria in all groups were not statistically significant. The mean number of Escherichia coli decreased due to feeding of pomegranate by-products (P<0.05), while the type of pomegranate by-product has not significant effect on number of Escherichia coli. The importance role of gut microflora is well recognized in GIT health, although population of gut microbes has been influenced by diet (Choct et al 1996). In contrast of useful effects of lactobacillus on GIT, Escherichia coli damages the intestine of animals and produces lipopolysaccharide (Munyaka et al. 2012). Tannins are considered as a toxin to microorganisms; these compounds in the soluble environment produce some stable complexes, mainly with protein and to a lesser extent with carbohydrates or some physiological ions elements such as iron and copper (Chung and Chou 1998). The pomegranate peel extract at different levels has antimicrobial effect against microorganisms such as Staphylococcus aureus, Escherichia coli, Candida tropicalis and Candida albicans (Ahmed et al. 2013). The phenolic materials in pomegranate fruit, are responsible for the antimicrobial properties of pomegranates (Seeram et al. 2006). In the present study, reduction of Escherichia coli population in lambs fed pomegranate by-products can be attributed to the adverse effect of phenolic substances in the pomegranate byproducts on Escherichia coli population. Several mechanisms have been introduced for antimicrobial properties of phenolic compounds in the pomegranate. Phenolic substances, with high molecular weight proteins, form complexes and by these complexes can react to the some cytoplasmic and membrane enzymes after absorption (Seeram et al. 2006). These complexes can also prevent cell surface receptors from attachment of harmful microorganisms (Cowan 1999). Phenolic compounds can react with the cellular proteins of microorganisms, alter cell wall structure and function (Hugo and Bloomfield 1971), reducing cell wall permeability and reducing substrate transport to cells (Goel et al. 2005). In addition, phenolic compounds can alter or denature some microbial enzymes, and also form complexes with certain nutrients and remove them from microorganisms (Hugo and Bloomfield 1971). The decline of Escherichia coli can also be attributed to the increase in the number of Lactobacillus; because by increasing the Lactobacillus and consequently increasing the production of lactic acid and creating an acidic environment, the population of Escherichia coli is reduced due to sensitivity of Escherichia coli to acidic environment (Hammer et al. 1999).

Feeding of the pomegranate pomace silage and air-dried pomegranate pomace in fattening lambs, decreased the population of Escherichia coli in ileum and cecum, although lactobacillus bacteria was not affected by pomegranate by-products. It seems that the tannins and phenolic compounds present in the pomegranate can effect on Escherichia coli population in ileum and cecum.

Bacillus probiotics have been recently considered in biotechnological researches, and food additives. The present study was aimed to investigate the effects of Bacillus subtilis probiotics (PY79 and ATCC 6633) and their metabolites on Salmonella Typhimurium in Caco-2 cells.

Cytotoxicity of B. subtilis ATCC 6633 crude supernatant (CS) was evaluated by 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. S. Typhimurium invasion assay was performed in the presence of the probiotics. Cell viability, apoptosis, and necrosis were evaluated in presence of S. Typhimurium , B. subtilis strains, and CS (4%, 8%) using flow cytometry.

Results showed a significant reduction in the invasive ability of S. Typhimurium to Caco-2 cells by employing B. subtilis probiotics, and CS‏) ‏p < 0.05‎‏). The less invasion was indicated in B. subtilis PY79 and Salmonella co-cultural group. Furthermore, the cell survival rates, and apoptosis/necrosis were respectively increased and decreased in co-culture groups (‏p < 0.05‎‏).

Hence, it seems that B. subtilis strains could be suggested as beneficial candidates to overcome the invasion and ‎cytotoxicity of Salmonella on the intestinal cells. However, additional in vivo models are suggested to validate our results.

Celiac disease (CD) is one of the most common disorders, resulting from both environmental (gluten) and genetic factors. The clinical features of the Iranian CD are still unknown and there is insufficient information about the atypical presentation of CD from Iran. As, many previous reports revealed an association between controlled protozoal infections and the CD according to cytokines production, the aim of this study was to determine the prevalence of CD and possible co‑infection with the most prevalent protozoal infections including Tropheryma whipplei, Cryptosporidium, and Giardia duodenalis among CD samples.

In this study, from April 2014 to November 2016, 524 samples were obtained from small intestine of patients with gastrointestinal diseases referring to the Pathology Department of Namazi Hospital, Shiraz, Iran. Multiplex polymerase chain reaction assay was then performed on the histological positive CD samples for the prevalence of the microorganisms.

Sixty‑four (12.21%) patients were diagnosed as having CD by histopathological examination. The prevalence of T. whipplei and Cryptosporidium spp. was 19 (29.69%) and 8 (12.5%) respectively, among CD positive samples there was no positive sample for Giardia lamblia.

The prevalence of CD among the southwestern Iranian population was high and comparable with other areas of Iran as well as many other countries. Furthermore, no significant association between the presence of T. whipplei, Cryptosporidium spp., and level of the histopathological changes of villi in the CD was observed (P > 0.05).

Foodborne pathogens are among the serious problems all around the world and thus a novel and natural strategy to control and to inhibit such pathogens is highly demanded nowadays. The aim of this study was to isolate a specific bacteriophage of Escherichia coli O157:H7 from sewage in Fars province, Iran to determine its morphological and antimicrobial activities.

In order to isolate the bacteriophage of E. coli O157:H7, 10 samples of slaughterhouse wastewaters were used. Double-Layer Agar method was employed to isolate the bacteriophage. To identify the fine structure of the bacteriophage, electron microscope was employed. Host range and antibacterial activity of the phage was also investigated, in vitro.

The morphological and biological characteristics of a virulent Siphoviridae phage, PI, are reported. It was found that infection of E. coli O157:H7 strains with this specific bacteriophage produce clear plaques. In the one-step growth analysis, it was confirmed that the phage has been characterized with a very short rise period (around 15 min), an average burst size of 193 PFU/cell, high infectivity and potent lytic action. The bacteriolytic activity of PI was also investigated, in vitro. It was also clarified that at the MOI of 100, 10 and 1, the phage rapidly lysed the bacterial cells within 0.5 or 2 h.

These results indicate that the phage PI is a newly discovered phage against E. coli O157:H7 in Iran which may be recommended to use as bio-control purposes.

The consumption of milk and unpasteurized dairy products contaminated with Brucella bacteria is one of the most important ways of brucellosis transmission to humans. The principal goal of this study was to determine the prevalence of Brucella abortus (B. abortus) and Brucella melitens (B. melitens)in unpasteurized dairy products consumed in Shiraz province. In this study conducted in 2016, 238 unpasteurized dairy products including 48 raw milk, 48 yogurt, 46 cheeses, 48 dough and 48 ice cream samples, were purchased from the retail market in Shiraz province and were examined by a specific PCR assay. This study showed positive 5/04% out of 238 unpasteurized dairy products including 9 out of 48 (18/75%) raw milk samples and 3 out of 48 (6.25%) yogurt samples). Contamination was not detected in samples of dough, cheese and traditional ice cream. The results also showed that among 12 positive samples, 6 samples were contaminated with B. abortus (including 4 milk samples  and 2 yogurt samples), 2 samples were contaminated with B. melitensis (including 2 Milk samples) and 4 samples were contaminated simultaneously with B. abortus and B. melitensis (including 3 milk samples and 1 yogurt sample). The present study suggests the unpasteurized dairy products as the major sources of brucellosis in Shiraz province, South of Iran; thus, to prevent brucellosis in human, the consumption of pasteurized milk and dairy products is highly recommended.

Bacillus coagulans is a spore-based probiotic, resistant to environmental and gastrointestinal conditions. The ability to form spores makes this probiotic resistant to technological stresses. The purpose of this study was to investigate the effects of Bacillus coagulants (Bacilact®) as a food additive on the production level, dry matter, fat percentage, crude protein, casein, serum protein, and microbial load, and the number of the somatic cell as important economic and health indicators of raw milk of cattle. This study was performed on 33 Holstein breeders divided into two groups; control (16 heads) and experimental (17 heads). Probiotics were added daily for 63 days at a rate of 2 grams per each cow. Sampling was completed every 21 days from starting the study. The addition of probiotic Bacillus coagulans did not affect the levels of milk production, dry matter, fat, lactose, milk serum, somatic cell count, and microbial load, but the level of protein and casein in the experimental group were increased. At days 42 and 63, protein levels were higher in the experimental group. The level of casein was higher in the experimental group on the days 42 and 63. Using probiotic Bacillus coagulans can be considered as an improving factor to increase the quality of milk and the quality of dairy products.

Human epithelial cells have been widely used to study the interaction between intestinal cells and pathogens, in vitro. In this study, the effect of probiotic bacteria Bacillus coagulans and its supernatant on the growth inhibition, cytotoxicity and induction of apoptosis caused by Salmonella Typhimurium and its adhesion to HT-29 cells were investigated.

B. coagulans supernatant was used to obtain the minimum inhibitory concentration. To evaluate the cytotoxicity and percent of apoptotic cells, B. coagulans and its supernatant (2, 4, 6 and 8% concentrations) with S. Typhimurium was added to HT-29 cells. The MTT assay was used in order to evaluate the cytotoxicity. Percent of apoptotic cells was reported using a fluorescence staining method. Additionally, the adhesion of S. Typhimurium to HT-29 cells was investigated. The effect of B. coagulans on the level of adhesion was also studied.

The most inhibitory effect was shown at the concentration of 80000 µg/ml supernatant of B. coagulans (54.77% ± 1.43). The simultaneous culture of S. Typhimurium with B. coagulans had the lowest amount of cytotoxicity and induced apoptosis among the all co-culture groups of S. Typhimurium with B. coagulans or its supernatant. The determined cytotoxicity and induced apoptosis were 26.06 % ± 3.79 and 17.63 % ± 2.14 respectively. In the adhesion test, it was observed that B. coagulans can significantly prevent adhesion of S. Typhimurium to HT-29 cell.

B. coagulans can reduce the adhesion, cytotoxicity and induction of apoptosis caused by S. Typhimurium in HT-29 cells in vitro.

Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular organism. In Iran, healthy cattle are the main reservoirs of these microorganisms. The consumption of milk and non-pasteurized dairy products is considered as a common way for transmission of infection from livestock to humans. Therefore, the present study aimed to determine the prevalence of C. burnetii in bovine bulk milk samples from dairy herds in Shiraz, southern Iran. A total of 100 bulk milk samples were collected from 20 traditional and 80 industrial dairy herds in Shiraz, southern Iran. The samples were then evaluated for the presence of the gene IS1111 using polymerase chain reaction (PCR) method. Three out of 100 raw milk samples (3%) were contaminated with C. burnetii. The prevalence rate in traditional and industrial dairy herds was 10 % (two samples) and 1.2 % (one sample), respectively. The bovine raw milk can be a potential source of C. burnetii in Shiraz, southern Iran. Implementation of good hygienic practices on dairy farms, as well as the avoidance of consumption of raw milk and non-pasteurized dairy products is crucial to reduce the risk of infection transmission.

Q fever is a worldwide disease which is common between human and livestock. This disease is created by an obligate intracellular Rickettsia called Coxiella burnetii (C. burnetii). Cattle, goats and sheep are among the main reservoirs of the disease in humans. The most common routs of transmitting the infection to humans are inhalation of contaminated aerosols and drinking milk and non-pasteurized dairy products. This study was aimed to determine the prevalence of C. burnetii in non-pasteurized dairy products in Shiraz. In this study (from summer 2016 to winter 2016), 238 non-pasteurized dairy products, (48 raw milk, 48 yogurt, 46 cheeses, 48 dough and 48 ice cream samples) were collected from the retail market and analyzed using a nested PCR assay. This study showed that 20 samples (8.4%) of 238 non-pasteurized dairy products were reported positive for C. burnetii (13 of 48 (27.08%) raw milk, 3 of 48 (6.25%) yogurt, 2 of 46 (4.35%) cheese, 2 of 48 (4.16%) dough and 0 of 48 ice cream samples). The present study suggests that non-pasteurized dairy as main sources of C. burnetii in Shiraz, Southern Iran; thus, the consumption of pasteurized milk and dairy products is a valuable method to prevent the disease in human.

With the advancement of nanotechnology, nanoparticles have been applied in our modern society. However, the hazardous effects of nanoparticles on organisms have not been thoroughly clarified yet. Considering the migration of nanoparticles in food and its subsequent consumption by humans, we have employed normal cell line, the African green monkey kidney cell line (Vero) for evaluation of the cytotoxic activity of the silver nanoparticles. Currently, there are various approaches to perform toxicity tests. In this study, we investigated the effects of citrate-based silver nanoparticles on Vero cells to explore the adverse effects of these nanoparticles. In an experimental work, to synthetize silver nanoparticles, silver nitrate and citric acid were used. Nanoparticles were further characterized by UV-Visible Spectroscopy, Dynamic Light scattering (DLS) and Scanning Electron Microscopy (SEM). Cells were exposed to various concentrations of the nanoparticles (1.56 to 1000 µg/ml) for 24 h and 48h. The cytotoxic activity and apoptosis were determined using MTT assay and acridine orange/ethidium bromide (AO/EB) staining, respectively. The present study showed a dose-dependent cytotoxicity of the silver nanoparticles with log IC50 values of ~ 10.68 and 2.06 µg/ml for 24 h and 48 h, respectively on Vero cell lines. Analysis by AO/EB staining indicated that the silver nanoparticles induced apoptosis in the cell lines. Silver nanoparticles revealed cytotoxic effects on the Vero cells which was associated with the method of synthesis of silver nanoparticles.

In recent years, an increase in antibiotic resistance has been observed in Salmonella in different countries. The aim of this study was to determine the tetracycline and enrofloxacine resistance in salmonella isolated from poultry.
The pattern of antibiotic resistance to tetracycline and enrofloxacin in isolated Salmonella of fecal broiler chickens from Shiraz, southern Iran, was assessed using minimum inhibitory concentration (MIC) and PCR methods.
Of 100 fecal samples of broiler chickens, 5 samples (5%) were infected to Salmonella. The antimicrobial susceptibility showed that MIC90 of isolated Salmonella strains for enrofloxacin and tetracycline was less than 0.2 μg/mL and 180 μg/mL, respectively, indicating a high sensitivity to these antibiotics. In two samples the presence of tetracycline resistance plasmid was also found, while all the strains were susceptible to enrofloxacin.
According to the results, the isolated Salmonella spp. showed higher resistance in tetracycline than enrofloxacin, which seems due to the excessive usage of this antibiotic in poultry industry.

In the present study, the Lut Desert, Iran was chosen as one of the hottest places in the world (with the recorded temperature of 70.7°C during 2003-2009) to find out whether any heat-resistant microorganisms were present in the soil.
The samples were collected from surface and depth of three identified places of Gandom Beryan in the Lut Desert. Chemical analysis and enumeration of the total bacteria, yeasts and molds were performed. Four selective culture media were employed to isolate the filamentous actinomycetes. The suspected colonies were further confirmed using PCR assay. Then the culture cell-free-supernatants (CFS) of isolates were used to investigate their antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium and Escherichia coli.
Chemical analysis of the samples included moisture (0.2-0.9%), ash (85-91%), organic materials (8.3-14.4%), pH (7.59-9.40) and electrical conductivity (380-2000 µS/cm). The number of isolated bacteria and molds varied from 0-20 to 0-40 CFU/g, respectively. Number of Actinomycetes isolated from the soil samples were between 0-12.2 CFU/g. Nine isolated colonies were identified as filamentous Actinomycetes. To determine the possibility of antimicrobial peptides, the CFS (cell-free supernatant) was firstly neutralized by NaOH and catalase. The results showed that none of the CFS of the isolates was effective against E. coli, S. Typhimurium and S. aureus, while the maximum inhibitory effect was investigated on B. cereus, which was 33.1%±1.19% (mean ± SD).
The results of the current study imply the presence of rare heat-resistant microorganisms in the soil of Gandom Beryan which may be further used to find out more about the function of natural bioactive compounds. Actinomycetes, as extremophile microorganisms, have shown the greatest genomic and metabolic diversity, as such the discovery of the novel Actinomycetes as a source of secondary metabolites is essential.

The protein listeriolysin O (LLO) encoded by hly gene, is one of the most important virulence factors of Listeria monocytogenes. This highly potent immunogenic cholesterol binding toxin has hemolytic activity, responsible for phagosomal membrane disruption and bacterial escape to the cytoplasm and facilitating the stimulation of CD8 T cells and Th1 response. Recently pathobiotechnological vaccination using probiotic bacteria have been proposed. One of these strategies is expression of LLO in non-pathogenic bacteria such as lactic acid bacteria as delivery strains.
Our aim in this study was cloning of hly gene in a Lactobacillus species via pNZ8110, an inducible expression vector which is specific for Lactococcus species.
hly gene was amplified by PCR and cloned into pNZ8110 by restriction enzymes cutting and ligation method. After transformation and propagation in E. coli MC1061 intermediate host, it was successfully electrotransformed into Lactobacillus plantarum.
Gel electrophoresis of colony PCR, extracted plasmids and restriction analysis along with sequencing confirmed the transformation. After induction using supernatant of nisin producer Lactococcus lactis NZ9700 strain, Expression of LLO was confirmed by SDS PAGE and western blot.
Here, we have employed a nonpathogenic probiotic strain; Lactobacillus plantarum for the first time to express hly gene of Listeria monocytogenes in order to propose a new vaccine candidate.

Several genetic mechanisms are used by Campylobacter spp. to achieve pathogenesis. One of the involved virulence factors is lipooligosacharide-associated genes, which are related to ganglioside mimicry by Campylobacter species.
The current study was conducted to determine the genetic diversity of 3 LOS-associated genes among Campylobacter jejuni and C. coli isolated from animal fecal samples.
One hundred broiler, cattle, and sheep fecal C. jejuni and C. coli isolates, which had been collected previously from Shiraz slaughterhouses and had been formerly identified by polymerase chain reaction (PCR) reactions, were used in the present study. Campylobacter species were subjected to detect wlaN, cgtB, and waaC genes. The PCR products of three LOS-genes were subjected for restriction fragment length polymorphism (RFLP) using HindIII and AluI restriction enzymes in separate reactions. The most prevalent RFLP patterns in the combination of 2 enzymes were subjected for sequencing and sequence analysis software.
Results and Patterns of RFLP for PCR products of all 69 wlaN and 29 cgtB genes were similar yet among 86 waaC gene PCR products, 6 different RFLP patterns were obtained. In conclusion, PCR-RFLP analysis demonstrated considerable variation in gene content and overall sequence heterogeneity in the animal-associated C. jejuni and C. coli LOS biosynthesis genes.

Probiotics are well-known as valuable functional foods to promote specific health benefits to consumers. Some Bacillus bacteria have been recently considered as probiotic and food additives. We aimed to investigate the growingrate of probiotic B. subtilis and B. coagulans using several enrichment media incubated at 37 °C for 24 hours.

Various enrichment media including nutrient broth (NB), tryptic soy broth (TSB), double strength TSB, Mueller Hinton broth (MH), brain-heart infusion broth (BHIB), de Man, Rogosa and Sharpe (MRS), and nutrient yeast extract salt medium (NYSM) were used to enrich the probiotics and they were subsequently incubated for 18 h at 37 °C. The bacteria were then enumerated on TSA medium.

The results showed that B. subtilis ATCC 6633, B. subtilis PY79, and B. coagulans developed in TSB, double strength TBS, TSB yeast extract, BHIB and NYSM, respectively. Moreover, the formulas were achieved based on the optical density curve and the number of bacteria.

Considering that the probiotics are significantly employed as food supplements, it is essential to identify appropriate enrichment media to proliferate these beneficial bacteria.

Plants are riched by phenolic compounds and considered as the main natural antioxidants. Many efforts have been recently made to clarify the source of natural antioxidants and their roles to protect from oxidative stress injuries. The present study was aimed to qualify the phenolic compounds of pomegranate peel extract (PPE) of Rabbab variety and their antioxidant effect to substitute the synthetic compounds. Folin- Ciocalteu method was employed to investigate phenolic compound, while, spectrophotometery is used to measure flavonoid, antocyanin and oxidative ability. The antioxidant activity of different concentration of PPE was measured using DPPH. Results showed the concentrations of 70.83 mg TAE/g, 21.33 mg CE/g and 136.66 mmol/100 mL corresponding to the phenolic, flavonoid and antocyanin compounds, respectively. The antioxidant effect by linoleic system has shown to inhibit 89.61% of linoleic oxidation in the methanolic extract of PPE. Increasing the concentration of phenolic compound was simultaneous to raise its effect and a significant correlation between the antiradical activity and its reduction ability in the methanolic extract. The current results revealed the antioxidant activity of methanolic extract of Rabbab variety PPE and thus are recommended to apply in food industries.

Thermophilic campylobacters, particularly Campylobacter jejuni and C. coli are the main agents of human campylobacteriosis. Campylobacter contaminated chicken products is the most important source of foodborne gastroenteritis. Evaluation of genetic diversity among Campylobacter population is critical for understanding the epidemiology of this bacterium and developing effective control strategies against Campylobacter infections and other related disorders.. The aim of this study was to investigate the polymorphism of thermophilic Campylobacter isolated from broiler fecal samples in Shiraz, southern Iran.. Ninety Campylobacter isolates were recovered from broiler feces using enrichment process followed by cultivation method. The isolates were species typing on the basis of polymerase chain reaction (PCR) detection of 16SrRNA and multiplex PCR for determining two thermophilic species. To evaluate strain diversity of thermophilic Campylobacter isolates, flaA PCR-Restriction Fragment Length Polymorphism (RFLP) was performed using DdeI restriction enzyme.. All 90 Campylobacter isolates confirmed by m-PCR were successfully typed using flaA-PCR-RFLP. Eleven different types were defined according to flaA-typing method and the RFLP patterns were located at three separate clusters in RFLP image analysis dendrogram.. Campylobacter jejuni isolates significantly showed more variety than C. coli isolates. A relatively low genetic diversity existed among C. jejuni and C. coli isolated from broilers in Shiraz, southern Iran. In our knowledge, this was the first report of genetic diversity among broiler originated human pathogen thermophilic campylobacters in Shiraz, southern Iran..

Campylobacter is one of the leading bacterial species causing foodborne illnesses in humans. Antimicrobial agents have been extensively used for treatment of Campylobacter infections; but in the recent years, both animal and human isolates of this bacterium have shown resistance to several antibiotics such as tetracycline.. The aim of this study was to investigate the presence of genetic determinants of tetracycline resistance in Campylobacter spp. recovered from poultry carcasses in Shiraz, Iran.. Eighty-three thermophilic Campylobacter spp. Isolates were first identified based on multiplex polymerase chain reaction (PCR) and then screened for presence of tetracycline resistance genes (tet (A), tet (B), tet (O) and te (S)) by PCR.. The overall prevalence of Campylobacter jejuni and C. coli among the examined isolates was 51.8% and 48.2%, respectively. Tetracycline resistance genes of tet (B) and tet (S) were not seen among these Campylobacter spp. Isolates, whereas the most common tet gene identified was tet (O), found in 83.1% (69/83) of all the isolates. The tet (O) gene sequence comparison between C. jejuni and C. coli showed 100% similarity and these sequences (JX853721and JX853722) were also identical to the homologous sequences of other strains of Campylobacter spp. existing in the GenBank databases. In addition, tet (A) was found in 18% (15/83) of Campylobacter spp. isolates. To our knowledge, this represents the first report of tet (A) in Campylobacter spp. There was 100% homology between the sequences of tet (A) from this study (JX891463 and JX891464) and the tet (A) sequences mentioned for other bacteria in the GenBank databases.. The high prevalence of tet (O) resistance gene along with new detection of tet (A) resistance gene in Campylobacter spp. isolated from poultry carcasses revealed an extensive tetracycline resistance among Campylobacter isolates from poultry in Iran. It emphasized the need for cautious use of tetracycline in poultry production to decrease the extension of tetracycline-resistant Campylobacter spp..

Food poisoning (FP) caused by C. botulinum is the most serious feature of FP inpeople consuming the contaminated foodstuffs (Canned meat, vegetarian foods, dairy products and seafood products). Botulism is basically detected by the identification of live bacteria and/or its toxins. Among various types of microorganisms (i.e. A, B, C1, C2, D, E, F), serotypes A, B, E and F are considered as the main human pathogens. The present study was aimed at investigating the possible roles of various foodstuffs to induce the food intoxication and also to compare the culture and molecular assays for identifying the microorganism. Three Lab techniques including biochemical, culture (enriched in TPGY and cooked meat medium) and MPCR were used to detect C. botulinum in the samples. As the molecular based techniques have recently employed for the rapid and reliable identification of the bacteria and its toxins, the PCR assay, using three pairs of primers were designed and optimized to identify A, B and E strains in the contaminated specimens. The PCR was able to amplify 782, 205 and 389 bp genes specified for A, B and E types of the bacteria, respectively. Total number of 290 specimens including fish, honey,"kashk"and"Dough" were tested, in which 5%, 4%, 2.5% and 1.25%, were found positive, respectively. Using selective culture of the specimens on the enriched samples, it was shown that just four samples were found positive. As a final conclusion, the molecular based techniques are recommended as a reliable tool to detect C. botulinum and, its toxins and spores in foodstuffs. Moreover, it is strongly advised to use it in food microbial Lab and also the epidemiological surveys.