خسرو عیسی زاده

The purpose of this study was to determine the frequency of Vibrio parahaemolyticus and to identify pathogenic and non-pathogenic strains of this bacterium using a series of biochemical tests and polymerase chain reactions from the shores of the Caspian Sea (Gilan Province). The water and sediment samples of the Caspian Sea were collected from the depth of 30-50 and 10-20 cm respectively by aseptic method. Sampling date, sampling location, temperature, pH and salinity were measured. Isolation and identification of environmental isolates was done using standard methods in order to determine the genus and species using specific media such as thiosulfate citrate bile sucrose and Vibrio chrome agar. A total of 55 isolates were identified by biochemical, phenotypic and polymerase chain reaction tests. From the total of 55 cases of Vibrio parahemolyticus isolated, the frequency of tdh and trh genes was 1 case (1.8%) and 3 cases (5.4%) respectively. This study showed that Vibrio parahaemolyticus, which have pathogenic potential, should be continuously monitored as agents of contamination of coastal waters. The isolation of these species indicates a health warning for people who use raw seafood or are in direct contact with the waters of the Caspian Sea are in this area.

Synthetic nanoparticles have unique physical and chemical properties. The most important characteristic of these nanoparticles is having a higher surface area than their counterparts of larger size. In this research 45 samples of dairy raw products after dilution of samples, to isolate Staphylococcus aureus and Escherichia coli were transferred to the Baird Parker Agar and Sorbitol Mac Conkey Agar media respectively, and were identified using a series of specific tests. Zinc oxide-doped nanopowder was synthesized by the sol-gel method. The antimicrobial effects of nanoparticles were investigated by the well diffusion method. The minimum inhibitory concentration (MIC) of Zinc oxide-doped nanopowder and minimum bactericidal concentration (MBC) were determined. The mean diameter zone of the inhibitory growth of strains of E. coli PTCC 1399 and E. coli (1) and E. coli (2) were 22.5, 18.5, and 15.4 mm respectively at a concentration of 50 mg/ml and the mean diameter zone of the inhibitory of S. aureus PTCC 1189, S. aureus (1) and S. aureus (2) standard strains were 24.5, 20.4 and 19.5 mm. In this concentration. MIC for E. coli PTCC 1399 was 1.75, and E. coli (isolate 1) and E. coli (isolate 2) were 1.55 and 3.13 mg/ml, respectively. In the case of further experiments, this nanoparticle can be used as a preservative.

The development of rapid and highly sensitive diagnostic methods has received significant attention. Enzymatic nanobiosensors are a promising approach, offering fast results based on specific interactions between nanoparticles, enzyme, and target molecules. This study investigated the potential of ZnO nanoparticles, SnO, and multiwall carbon nanotubes (MWCNTs) as marker molecules in a system using beta-galactosidase enzyme for bacterial detection. Following nanoparticle synthesis, their structure was confirmed using XRD, FTIR, UV-DRS analyses. Enzyme activity was evaluated in the presence of the substrate ONPG. Different nanoparticle concentrations were tested with a constant amount of enzyme to determine the optimal concentration for inhibiting lactase activity. Subsequently, varying concentrations of Escherichia coli were introduced, and the ability of each nanoparticle type to detect bacteria was compared. Due to their small size, high surface area, and strong reactivity, these nanomaterials demonstrated the potential to detect low  bacterial concentrations in the environment.Bacteria likely attached to the nanoparticles, hindering their intraction with the enzyme and consequently affecting enzyme activity. The results revealed MWCNTs to be most effective for bacterial identification, detecting as low as 10 CFU/mL bacteria within 15 min. This approach has promising applications in the food industry for rapid detection of low-level bacterial contamination.

Escherichia coli is an important indicator in the quality control of pharmaceutical and real samples. This study compares the detection of this bacterium by regular method and a biosensor based on Multi-Walled Carbon Nanotubes (MWCNTs) on glassy carbon electrodes (GCE) in pharmaceutical and water as real sample.

In this experimental study, the conventional culture method (pour plate) and modified biosensor based on Multi-Walled Carbon Nanotubes on glassy carbon electrode with the arrangement of GC/MWCNTs/AuNPs/Ab/BSA were used for the detection of E. coli. Dilutions of E. coli between (1 ×101–1×108 CFU/ml) were used in pharmaceutical and water samples, prepared in 0.1 M PBS (pH 7.4), mixed with 0.5mM acetaminophen. The efficiency of the designed biosensor was investigated using SEM, Cyclic Voltammetry, and Square-Wave Voltammetry electrochemical techniques, as well as interfering bacteria.

The results of E. coli detection using the conventional culture and designed biosensor were not statistically significant. The designed biosensor had a high sensitivity with accuracy in 3 minutes and LOD 3.02 CFU/ml for Escherichia coli.

Considering the time-consuming and influenced by environmental factors in the microbial monitoring of pharmaceuticals for E. coli detection in conventional methods and the risk of losing pharmaceutical products, the biosensor has good efficiency in detection with low cost and no need for enrichment in a small volume of samples.

Actinomycetes are known as the largest reservoir of natural antibiotics in the world. For this reason, due to their ability to produce various antibiotics and other compounds of therapeutic importance, they are considered the golden microorganisms of the 21st century. The purpose of this research is the isolation and molecular identification of actinomycetes with antimicrobial properties from agricultural soils in the native areas of Guilan province. Soil samples were collected from the southwestern agricultural areas of Guilan province. Serial dilution was used to isolate actinomycetes. Then the morphological, physiological, and biochemical identification of the samples was done and finally, the molecular identification of the isolates was done using 16S rRNA sequencing and phylogenetic analysis. Antimicrobial activity was investigated against pathogenic microorganisms. A total of 14 isolates were identified.2 isolates with more antimicrobial properties were selected. Based on the results of phylogenetic studies and 16S rRNA sequencing, Amycolatopsis roodepoortensis strain EA7 with 99.63% confidence, and Streptomyces microflaveus strain EA6 with 93.92% confidence were identified. The isolated bacteria had more antimicrobial activity against Gram-positive pathogenic microorganisms Staphylococcus aureus and standard sample Staphylococcus aureus PTCC 1112. This research is the first report on the identification of actinomycetes with antimicrobial properties in the agricultural soils of the southwestern regions of Guilan province located in the Alborz mountains. The identification of the rare strain of Amycolatopsis roodepoortensis strain EA7 from the northern regions of Iran makes the soils of these regions very valuable.

Probiotic bacteria, including lactobacilli, are known to prevent many cancers. In this regard, the present study aimed to evaluate the anti-cancer effects of Lactobacillus cytoplasmic extract isolated from dairy products in Guilan province on the HT-29 colon cancer cell line.

In this study, Lactobacillus bacteria were isolated and identified from dairy products based on conventional culture and biochemical methods. Then, using specific primers, the 16S rRNA gene of the bacteria was amplified and the confirmed samples were compared with the sequences in NCBI after sequencing. Different concentrations of 0.5, 0.75, 1, 1.5, and 2 mg/mL were made from the cytoplasmic extract of the selected strain. Finally, the cytotoxicity effects of Lactobacillus cytoplasmic extract on cancer HT-29 and normal HUVEC cell lines were investigated by the MTT method.

The results of the MTT assay showed that the cytoplasmic extract of Lactobacillus dose-dependently reduced the survival and proliferation of colon cancer cells at 24 h, with the highest inhibitory effect at 2 mg/ml. Concentrations of 1, 1.5, and 2 mg/mL decreased cell viability by 50±4.87%, 40±8.61%, and 25±5.80%, respectively. The IC50 value of the cytoplasmic extract was 1.43 mg/mL for the HT29 cells. Also, cytotoxic effects on the normal HUVEC cell line were not observed.

According to the results of the study, the cytoplasmic extract of Lactobacillus isolated from dairy products reduced the growth of HT-29 cancer cells, which with further studies can be used as a biological product in the treatment and prevention of colon cancer.

 Escherichia coli  (E.coli) is an essential bacterial indicator in the control of pharmaceutical quality and other similar fields. There are some biosensors designed for its detection based on electrochemical transduction methods. A biosensor with reduced graphene oxide was modified. Traditional methods are time-consuming and high prices, so in this study a new biosensor with modification of reduced graphene oxide (rGO) as a kind of carbon composition on glassy carbon electrode (GCE) with Au Nanoparticles (Au NPs) decoration was used for E. coli detection.

 Reduced graphene oxide (rGO)  modified on glassy carbon electrode (GCE) and chronoamperometric and reduction methods were used for Au NPs decoration and it was completed with polyclonal E. coli antibody and 0.5 W/V% Bovine Serum Albumin (BSA) solution. Morphology and structure of rGO and Au NPs in GCE/rGO/Au NPs/ E. coli polyclonal antibody/ BSA biosensor were verified by SEM (Scanning Electron Microscope) during modification steps. E. coli detection in dissimilar samples was performed by Square-Wave Voltammetry (SWV) and Cyclic Voltammetry (CV) techniques which were set in 0.1M phosphate buffer solution (PBS) (pH 7.4) mixed with 0.5mM acetaminophen. In comparison with the biosensor, the classical method of detection was performed with serial dilutions of E. coli ATCC 8739 (1×101–1×108 CFU/ml) which was cultured on media. 

 Despite the two methods used to stabilize Au NPs, scanning electron microscope (SEM) images showed that the current difference did not increase due to gold particles. Its modification had not significant change in current and it was not a successful experiment for E.coli detection.

 Compared with the plate method, biosensor couldn’t substitute with conventional methods for E. coli detection.

Due to the negative effects of cancer, various methods such as surgery, chemotherapy and radiotherapy are used to treat cancer and are used as primary methods in the treatment of colorectal cancer. However, the success rate of this treatment is not enough and the death rate due to it increases every year, and a series of necessary strategies are needed to control this deadly disease (5). In general, the main characteristic of cancer cells is uncontrollable cell proliferation and resistance to programmed death, so an agent that causes apoptosis in cancer cells can be known as an anticancer substance (8). Among various cases, probiotics control the digestive enzymes of animals and humans, inhibit cancer agents in the body and in laboratory conditions, and also play an important role in suppressing compounds and tumors caused by cancer in laboratory animals (9, 10). HT29 is not only used to study the biology of human colon cancers, but is of particular interest in studies focused on digestion and accessibility due to its ability to express the characteristics of colon cells (11). HUVEC are human umbilical vein endothelial cells used to study endothelial cell function and pathology (eg, angiogenesis). Primary isolated HUVECs are probably the most popular used in research, as human umbilical vessels are more readily available than other blood vessel types (8). Today, due to the increasing prevalence of gastrointestinal cancer, this issue is considered as an important global health challenge, and in the past few decades, it has been shown that the imbalance in the intestinal microbiota is related to the rate of various chronic disorders, including cancer. Oral administration of different strains of probiotics can prevent the occurrence of cancer or reduce the incidence of inflammation after surgery (12). Therefore, the researcher is trying to answer the question whether probiotic properties and toxic effects of Lactobacillus cell extract isolated from dairy products of Gilan province have an effect on HT-29 cancer cell line and normal HUVEC cell or not.

In order to carry out this research, lactobacilli were first isolated from dairy samples, then morphological, biochemical, genetic and phylogenetic identification was performed on them. Using sequencing and then analyzing the determined sequences on the NCBI site, Lactobacillus fermentum species (L. Fermentum) was detected with 88.61% homology and its phylogenetic tree was drawn and registered as Limosilactobacillus fermentum GL strain. The isolated lactobacillus extract was affected on the HT-29 cancer cell line and normal HUVEC cells, and the survival of the cells under the effect of lactobacillus was determined using the MTT test (3-(4,5 dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide) was investigated. Finally, considering that all the tests were performed in triplicate, Minitab ver16 software and GraphPad Prism ver9 software were used to determine the mean (One-Way Unstacked ANOVA) and standard deviation, respectively (p < 0.05).

The results showed that the bacteria were gram positive, catalase negative, oxidase negative, negative movement, no growth at 15°C and growth at 37°C and 45°C. Also, molecular analysis showed the amplification of S rRNA16 gene in two of the 4 samples. Further, the blast results showed that the desired sequence of one of the samples with 61.88% similarity belongs to Lactobacillus fermentum. Then, the phylogenetic tree resulting from the analysis of S rRNA 16 sequence was performed by NCBI genome database and MEGA 7 software, and its relationship with other bacteria is shown. Finally, gene registration was done from the sequence obtained in the NCBI database and the desired bacterium was named Limosilactobacillus fermentum GL. Also, the results of cell viability were evaluated using the MTT colorimetric method. Based on the results, cytoplasmic extract in concentrations of 0.5, 0.75 mg/ml did not significantly change the cell viability of HT-29 cells, and concentrations of 1, 1.5, 2 mg/ml increased cell viability by 4.87±50%, respectively, decreased 8.61±40%, 5.80±25%. The IC50 value of cytoplasmic extract for HT-29 cells was 1.43 mg/ml. Also, the results of the cytotoxicity study showed that the concentrations used of the cytoplasmic extract had no inhibitory effect on the normal HUVEC cell line for 24 hours (P<0.05).

Despite recent advances in cancer treatment strategies, cancers are one of the most important causes of death worldwide. Although some anticancer treatments such as surgery, chemotherapy, and radiotherapy have been used with varying degrees of success in many types of cancer patients, these treatments are expensive and have harmful side effects including cardiotoxicity, diarrhea, intestinal strictures, and Inability to effectively absorb nutrients. Probiotics have been suggested as supplements to increase the effectiveness of anti-cancer treatments (24). The results showed that the concentrations of 1, 1.5 and 2 mg/ml of lactobacillus extract can reduce the cell viability by 50±4.87, 40±8.61 and 25±5.80% respectively during 24 hours. . Based on the MTT test, a concentration of 1 mg/ml of the cytoplasmic extract inhibited 50% of HT29 cells and had no toxic effect on normal HUVEC cells. In a study after 24-hour treatment of HT29 cells with 109 CFU/mL of Lactobacillus casei ATCC 393, cell survival decreased by 78% (13). Probably, in the future, these species or their metabolites can be used as food supplements or additives with anti-cancer activity, and for the production of such products, the selection of Lactobacillus strain is of high value (4). As shown in the results, the cell extract of Limosilactobacillus fermentum GL had important effects on growth inhibition in HT-29 cells by suppressing cell proliferation. However, the exact underlying mechanisms of the effects of probiotics on cancer cells have not been fully defined (4). It should be noted that the bacteria used in this study (Limosilactobacillus fermentum GL) were isolated from traditional dairy samples of Gilan and their anti-proliferative and anti-cancer effects were investigated for the first time.

Owing to the high cytotoxicity, introduction of anticancer pharmaceuticals to the encironment via pharmaceutical and hospital effluents is regarded a major health threat for eukaryotes. Exploring bacterial cells, as prokaryotic organisms, could be a novel approach for the removal of these compounds. Therefore, in this study, we aimed to isolate and identify oxaliplatin degrading bacteria from pharmaceutical wastewater samples and to evaluate their oxaliplatin removal potential as single and multi-species systems.

Bacterial isolation was performed using the membrane filtration method and the inhibitory effect of the drug for the isolated bacteria was evaluated in 96-well plates. Finally, oxaliplatin removal efficacy of the single and multi-species bacterial populations was determined using the High-Pressure Liquid chromatography (HPLC).

A total number of five bacterial species, including Enterobacter agglomerans, Citrobacter youngae, Xenorhabdus nematophilis, Bacillus lichineformis and Moraxella spp.able to degrade oxaliplatin were isolated. The highest and least oxaliplatin degrading potential was observed for B. lichiniformis (52%) and E. agglomerans (21%), respectively. Also, the multi-species treatment containing B. lichineformis, X. nematophilis, E. agglomeran showed the highest oxaliplatin removal efficacy (79%).

This work reveals that the bacteria isolated from pharmaceutical effluents could be employed for oxaliplatin removal and could be considered as a novel approach for the reduction of pharmaceutical pollutants.

 Enterococcus faecalis (E. faecalis) is a major opportunistic pathogen that causes nosocomial infections in humans, especially in immunocompromised and elderly people. This bacterium can survive and grow in harsh conditions and low-nutrient environments, so it is usually found in water and can easily be transmitted via the fecal-oral route. Due to the high usage of antibiotics, many antibiotic-resistant strains of E. faecalis have been evolved, especially vancomycin-resistant ones (VRE). Water-borne VRE is an environmental and health problem. Since the monitoring of recreational waters is so important in human health, the aim of the present study was to investigate the prevalence of VRE isolates and their antibiotics patterns in the environmental samples from recreational waters in Guilan Province, Iran.

 The environmental samples were obtained from recreational waters in six cities in Guilan Province, North of Iran, 4 stations in Anzali wetland, and 5 main rivers entering Anzali wetland from January to September 2019. E. faecalis samples were identified by microscopic analysis, biochemical tests, and molecular identification. Antibiotic resistance patterns of the isolates were determined by an antibiogram test. The molecular identification of the isolates was performed using polymerase chain reaction (PCR) with specific primers for the ddlE gene.

Overall, in 268 samples, Enterococci were detected in 154 samples (57.46%), of which 35 isolates (29.68%) were VRE. From VRE isolates 32 isolates (91.42%) belonged to E. faecalis, 2 isolates (5.71%) belonged to E. faecium, and one isolate (2.86%) belonged to other Enterococcus species.

This study shows the high prevalence and antibiotic resistance rate of VRE strains of E. faecalis in water resources in Guilan province, which can be alarming and needs to be considered.

Streptomyces have the ability to produce bioactive metabolites such as antibacterial compounds. This study aimed to isolate and evaluate the production of  antibacterial compounds from marine sediments by Streptomyces of eastern Gilan province. 

Marine sediments were collected and Streptomyces species were identified based on morphological, physiological, biochemical methods and molecular identification was used by 16SrRNA gene sequencing and phylogenetic analysis. Antimicrobial activity was evaluated against pathogenic microorganisms such as Micrococcus luteus PTCC 1408, Bacillus cereus PTCC 1154, Staphylococcus aureus PTCC 1189, Pseudomonas aeruginosa PTCC 1310, Salmonella typhi PTCC 1609 and Proteus mirabilis PTCC 1776 by using primary (Cross streak) and secondary (Well diffusion agar) methods were investigated.                                                                         

The isolate SN7 was collected from marine sediments of eastern Gilan province, Iran and the results of 16SrRNA gene sequencing and phylogenetic analysis revealed that the isolate belonged to Streptomyces genus with the highest similarity (90.17%) to uncultured Streptomyces sp. and it can be introduced as a new species. This isolate showed significant antimicrobial activity against pathogenic microorganisms and P. aeruginosa was the most resistant microorganism against antimicrobial activity of this isolate.

The results showed that the marine sediments of the eastern regions of Gilan province, Iran can be significant for producing antimicrobial compounds and these regions can be valuable for pharmaceutical application.

Polyhydroxybutyrate is a biopolymer Produced by bacteria. Also, with having chemical and physical characteristics similar with artificial plastics are completely biodegradable and compatible with life-environment. This study has been done with the purpose of separating and knowing one local strain with the ability of high-production for industrial purposes.

In the present analytical research, the sampling from petrochemical wastewater has been done. The existence of polyhydroxybutyrate in separations has been studied with Sudan black staining. One separation of bacillus was chosen to increase the production of polyhydroxybutyrate. This separation was distinguished with biochemical methods and determining 16S rRNA gene sequencing. The final confirmation of Polyhydroxybutyrate synthesis was done through Fourier transform infrared spectroscopy and Proton nuclear magnetic resonance. To increase more production of polyhydroxybutyrate, the effect of different factors including carbone, nitrogen, pH and temperature were assessed.

As a whole, eight bacterial isolation producing polyhydroxybutyrate were separated that among them the one novel strain of bacillus cereus was chosen as better separation. The best conditions to increase more production of polyhydroxybutyrate, was the application and use of glucose as carbon source, ammonium sulphate as nitrogen source, 7 pH and 30°C temperature.

Valuable data on optimized conditions for PHB production has been obtained through the present research that can be used at industrial level for PHB production, so it can be called a quick appearing alternation for petroleum based on synthetic plastic.

Streptomyces are microorganisms that are present in a variety of natural resources, especially in the soil, and can produce a wide variety of antimicrobial compounds. The prevalence of microbial resistance among pathogen microorganisms is increasing. The purpose of this study was to isolate and identify Streptomyces producing antimicrobial compounds with molecular methods and optimize its production conditions.

Streptomyces isolated from the soils of different regions of eastern Gilan province. Then, morphology, physiology and biochemical identification of the isolated samples were investigated. Finally, the identification of the isolates was carried out using sequencing of 16 SrRNA and phylogenetic analysis. Antimicrobial activity against tested pathogenic microorganisms and optimization of antimicrobial compounds produced in nutrient media and different conditions such as carbon and nitrogen sources, pH, incubation time and temperature were performed.

Based on the results of phylogenetic studies and sequencing of 16SrRNA, 97.34% confidence was detected in Streptomyces tendae strain 944. The bacterium had antimicrobial activity against pathogenic microorganisms including Micrococcus luteus PTCC 1408, Bacillus cereus PTCC 1154, Staphylococcus aureus PTCC 1189, Pseudomonas aeruginosa PTCC 1310, Salmonella typhi PTCC 1609 and Proteus mirabilis PTCC 1776. After optimization, the best culture medium, pH, optimum temperature, carbon and nitrogen sources and incubation time were ISP2, 7, 28 0 C, glucose, yeast extract and 7 days respectively.

The first report of screening of Streptomyces producing bioactive compounds in the eastern regions of Guilan province, show that the soils of the eastern regions of Guilan province are a very rich source of streptomyces producing antimicrobial compounds that can it is very important to produce natural-antimicrobial compounds.

Nowadays, biodegradation of oil pollution using native bacteria isolates is considered in different research programs. The purpose of this study was to investigate biosurfactant production and degradation of oil spills on Caspian Sea coastlines using native bacterial isolates. Sediment and oil spills samples were isolated from seven stations in the coasts of Bandar Anzali and Kiah Shahr. Biosurfactant production was evaluated using quantitative and qualitative methods such as hemolysis on blood agar, oil spreading method, droplet disintegration, emulsification activity and surface tensile test. Also, total hydrocarbon of oil was estimated. Biodegradation of compounds in sediments and petroleum analyzed using gas chromatography mass spectrometry (GC-MS) method. Identification of strains was performed using different morphological, biochemical and sequencing of 16S rRNA genes. Amongst 115 isolates, 57 isolates showed biosurfactant activity based on qualitative methods, and 15 strains with highest biological removal efficiency were selected for further studies. The spectrophotometry results showed the J3 isolate could remove 94.6% of oil within 7 days, was the most potent isolate in removal of hydrocarbons. Gas chromatography analysis indicated that 90% of aliphatic compounds were removed byJ3 strain in 21 days. The isolates J3, J5, and J12, which showed highest biosurfactant activity, were identified as strains of Bacillus cereussenso latu, Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Discussion and conclusion: The results of this study showed that the isolated strains showed suitable decreasing hydrophobicity and removal of oil hydrocarbons. So, it can be concluded that isolated J3, J5 and J12 are potent microorganisms in cleaning of contaminated waters by oil and other hydrocarbons.

Streptococcus sanguinis and mutans are dental infections agents. Due to the adverse effects of chemical mouthwashes, the aim of the present study was to determine the antibacterial effects of cetylpyridinium chloride mouthwash and alcoholic extracts of Melissa officinalis plant on the growth of these bacteria.
In this laboratory study, M. officinalis leaves were collected and extracted using percolation method. Well diffusion method and determination of minimum inhibitory and bactericidal concentrations were used for the antibacterial effects determination of alcoholic extracts of the plant and mouthwash in the concentrations of 250, 125, 62.5, 31.25, 15.62, 7.81, 3.9, 1.95, 0.97 and 0.48 mg/ml. Statistical analysis was performed using Pearson’s correlation coefficient.
The most antibacterial effect of ethanolic and methanolic extracts of M. officinalis and mouthwash on S. mutans and sanguinis was in the concentration of 250 mg/ml and the least inhibitory concentrations against S. mutans were 3.9, 31.25 and 15.26 and against S. sanguinis were 31.25, 15.62and 31.25 mg/ml, respectively. The minimum bactericidal concentrations of ethanolic and methanolic extracts of M. officinalis and mouthwash against S. mutans were 125, 62.5 and 31.25 and against S. sanguinis were 62.5, 31.5 and 62.5 mg/ml, respectively. There was a positive significant correlation between increasing concentration of extracts and inhibition of bacterial growth (p It seems that M. officinalis extract like mouthwash can be used as an oral and teeth antiseptic. However, in-vivo tests and proves that there is no harmful effects on the human body are essential for the production of this type of herbal mouthwash.

Aim and Lincomycin is a constituent of the lincosamide group, which typically feature a 6, 8-dideoxy-6-aminooctose lincosamine. The purpose of this study was to optimize production of lincomycin by streptomyces lincolnesis PTCC 1629 using classical one-factor-at-a-time method.
Material and Streptomyces lincolnesis PTCC 1629 was provided from Persian Type Culture Collection, Tehran, Iran. Starch casein agar and yeast extract-malt extract media were used for primary culture and production of lincomycin, respectively. Optimization of carbon and nitrogen sources were performed according to classical one-factor-at-a-time method. Antimicrobial susceptibility tests were analyzed using standard strains including; Micrococcus luteus PTCC 1408, Staphylococcus aureus PTCC 1189, Streptococcus pyogenes PTCC 1447, Staphylococcus epidermidis PTCC 1435, Bacillus cereus PTCC 1154, Escherichia coli PTCC 1395, Salmonellatyphi PTCC 1609 and Shigella flexneri PTCC 1234.
The obtained results showed that glucose and potassium nitrate were the most suitable carbon and nitrogen sources for lincomycin production by S. lincolnesis PTCC 1629, respectively. Amongst the test strains gram positive bacteria were susceptible to lincomycin production by S. lincolnesis PTCC 1629, but gram negative test strains were resistant to this antibiotic.
Theobtainedresults in this study showed that optimization of carbon and nitrogen sources could improve lincomycin production by S. lincolnesis PTCC 1629 with significant antibacterial activity against gram positive bacteria.

The antibacterial effect of different concentrations of zinc oxide nanoparticles on standard and isolated S. aureus and E. coli from food were studied. In this experimental study, suspension has been prepared from commercial ZnO nanoparticles in broth medium. After preparing standard strain and the strain were isolated from food samples, the effect of 1 and 2 times of Minimum Inhibitory Concentration (MIC) and also MBC test for ZnO nanoparticles on bacteria in different time were analyzed. According to the results obtained in this study, the maximum diameter of growth inhibition related to the concentration in5000 μg/ml zinc oxide nanoparticles for standard and isolated strain of E. coli. The average diameter of growth inhibition of standard strain of E. coli PTCC1399 and S. aureus PTCC11189 respectively were17.4 and 20.5 mm. The average diameter of the growth of E. coli and S. aureus isolated from foods respectively were 18.4 and 15.4 mm. A comparison of average MIC and MBC ZnO nanoparticles on the bacteria strains by Duncan test (p˂0.005) showed that the MBC is higher than the MIC in whole position bacteria. A ZnO nanoparticle among bacteria has most inhibition onS.aureu and for E. coli ST showed least impact. Results showed that mean comparison testis significantly different. Among times, zero time has the highest OD and the lowest OD was obtained in 240 second. This study showed that zinc oxide nanoparticles can be used to inhibit mentioned bacteria and can be a potential for alternative preservatives to prevent food spoilage possess.

Aim and Lincomycin is one of the licozamid compounds. The aim of this study is optimization of lincomycin production using one-factor-at-a-time-method and antimicrobial activity of this antibiotic by Streptomyces lincolenesis PTCC 1629
Material and At first different inorganic and organic carbon and nitrogen sources such as glucose, sucrose, lactose, maltose, fructose, potassium nitrate, sodium nitrate, ammonium sulfate, KH2PO4, CaCl2, CaCo3 were optimized for lincomycin production using one-factor-at-a-time method. Then antimicrobial activity assessed on refrence strains.
The results showed that glucose, potassium nitrate were the best carbon and nitrogen sources for lincomycin production by Streptomyces lincolenesis PTCC 1629. Also, the obtained results showed that gram positive strains were sensitive to lincomycin produced by this strain, but gram negative strains were resistant.
The obtained results showed that glucose in preculture and production media was the best carbon source for lincomycin production. The best pH and temperature for lincomycin production were 2/7- 8/6 and 30-28°C, respectively.

Amikacin, as an aminoglycoside antibiotic, is prescribed against a broad spectrum of bacteria. Limiting the use of this medicine includes the risk of microbial resistance, toxicity and short half-life in the body. One strategy to overcome the problem is the use of nanotechnology which can help to development of medicine delivery systems. This study was done in 2015 to assess the ability of mesoporous silica nanoparticles in improving the traditional formulation of amikacin.
SBA-15 was synthesized using hydrothermal method. The kinetics of medicine release from carriers, was investigated at 37 °C. The antimicrobial activity of formulations was conducted by disk diffusion method and broth dilution test on samples of bacteria.
Nanoparticles SBA-15 with a hexagonal arrangement and pore diameter of 5 -100 nm, were able to encapsulation 47% of Amikacin. The kinetics of medicine release from the carrier at pH (5, 7.4and 8.9) showed that in the first 24 hours, respectively, 10, 34.54 and 69% amikacin was released from the carriers. The rate of MIC of native amikacin and amikacin@SBA-15 of S. aureus were respectively, 1.66, 13.29 μg/mL and for P. aeruginosa were respectively 3.32, 26.59 μg/mL.
The results confirmed the stability of the encapsulated amikacin and high capacity SBA-15 to control the medicine release in the acidic environment of the stomach to the intestinal alkaline that made hopes to provide oral formulation of the medicine.

Expansion of industrial activities، mining and metal plating could cause releasing amount of high heavy metals into seawater and marine sediment led to heavy metals resistant microorganisms. Due to important role of Streptomyces in production of secondary metabolites، enzymes and elements reduction ability، were studied isolation of heavy metals (cadmium and chromium) resistant Streptomyces from marine sediments and coastal waters of Caspian Sea. Marine sediments and water samples were collected from coastal locations aseptically. SCA and KUA were used for the isolation of Streptomyces and biochemical testes like lipid، casein، starch hydrolysis and etc. carried out for identification of Streptomyces and determination of heavy metals (Cr، Cd) resistant Streptomyces was performed with well diffusion assay and for detection of MIC and MBC used Microdilution assay. Also، amounts of heavy metals in different parts of coastal waters measured with atomic absorption spectrophotometry assay. A total of 41 Streptomyces isolated from coastal locations 7 isolated (17/07%) showed chromium resistant to 300mg/l، 5 isolated (12/19%) showed cadmium resistant to 600mg/l. There was a significant difference between Streptomyces، temperature، pH and salt concentration (P < 0. 01). Due to existence of heavy metals (Cd،Cr) resistant Streptomyces in the Caspian Sea probability can use them as well suited agents for Bioremediation.

Mycobacterium marinum is a slow growing nontuberculosis mycobacterium. This organism can cause disseminated granulomatous infections in fish, called ‘fish tuberculosis’. Changes in nutritional components in culture medium and environmental conditions may lead to some changes in growth patterns and biofilm formation having new characteristics. The aim of this study was the evaluation of changes in medium components and environmental factors on the growth pattern and biofilm formation of M. marinum CCUG 20998. M. marinum CCUG 20998 was grown in 7H9 broth medium containing different concentrations of Tween 80 (0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 % v/v), Oleic Albumin Dextrose Catalase supplement (OADC), (4, 8, 12, and 16 % v/v) and glycerol (30, 35, 40, 45, and 50 % v/v). The changes in growth patterns and biofilm formation were determined by using measurement of optical density and staining by crystal violet. The obtained results showed that maximum growth was at 0.4 % of Tween 80. Oleic Albumin Dextrose Catalase supplement at different concentrations did not show any significant effect on the growth pattern. Decreasing the glycerol concentration significantly decreased the growth rate. The maximum biofilm formation was obtained in 35 % glycerol without Tween 80 and OADC in culture medium. Discussion and According to the obtained results, Tween 80 and glycerol in the formulation of Middlebrook 7H9 Broth are very critical for M. marinum CCUG 20998 growth. In contrast, Oleic Albumin Dextrose Catalase supplement can be omitted from the medium formulation due to showing no significant effect on the growth pattern.

Enterobacter are found in water, sewage and plants. Lactobacillus  are one of the dominant microorganisms in normal flora of intestinal tracts, genital system and respiratory tracts of humans and animals. The aim of this study was to evaluate the antagonistic effects of Lactobacillus acidophilus and Lactobacillus plantarum against Enterobacter cowanii isolated from broad bean plant.

In this sectional study Fava plants were collected, and after sampling, the samples were cultured on selective and specific King B  media. The presence of E. cowanii was confirmed based on biochemical and molecular techniques. Then, antagonistic effects of produced bacteriocins by L. plantarum and L. acidophilus on E. cowanii with well diffusion method on basis of pH were studied.

Based on this study, the growth inhibition zones produced by L.plantarum in different pH against E.cowanii were higher than that by L.acidophilus. Furthermore, the highest inhibition zone of Lactobacilli was observed in pH 4. 

According to antagonistic effects of lactic acid bacteria in the inhibition of E.cowanii, this factor can be used for treatment of the diseases caused by this factor.

Helicobacter pylori is the main reason of different gastrointestinal diseases. Studies have shown that the diversity of infection outcomes resulted from H. pylori may be associated with differences in genotypes or bacterial pathogenesis factors expression and also environmental and host factors in isolated H. pylori strains in patients with CagA and VacA. Thepurpose of this study is to determine the frequency of cagA gene in helicobacter pylori levels separated from patients suffering from lower gastrointestinal disorders. This study is a cross- sectional descriptive one, carried out on 127 patients referred to gasterointestinal clinic of Guilan Province, Gastrointestinal and Liver Research Center, in which the frequency of cagA gene in 50 separated helicobacter pylori cases was investigated using polymeras chain reaction (PCR). The used statistical test was Chai Square. Among the studied samples, in 50 cases bacteria were isolated by culture method. After performing PCR, the frequencies of cagA gene in strains from patients with mild antral gastritis, erosive gastritis, duodenal ulcer, gastric ulcer were equivalent to 85.7% 64.3%, 100% and 100%, respectively. There were significant differences in the association of this gene with isolated strains from patients with erosive gastritis (p<0.05), but the difference was not significant for the isolated strains from patients with mild antral gastritis, duodenal ulcer, and gastric ulcer. This study has shown that H. pylori cagA gene level was higher among patients with gastric ulcer and duodenal ulcers.

Bacterias are considerd as the most important factor to cause infections and food poisoning، so that microbial contamination in food is thought to be an increasing worldwide crisis. Current studies have been conducted aiming to determine the microbial contamination rate in food samples in East Gilan. In this cross-sectional descriptive study، 606 different food samples have been randomly sampled and sent to Azan university of Lahijan according to the type and source، in order to determine the diversity of bacterial quality of foods، and moreover have undergone the experiment as for assessing the bacterial contamination. This study has shown that the bacterias of Escherichia coli، coliform Mesophile are taken into connsideration as the most pollutant foods (P<0. 001). So that the sum of 11/55% contamination with E. coli، 6/97% contamination Mesophile and 6/8% contamination of the observed forms have to do with coliforms، The highest rate of bacterial contamination are linked with lettuce salad، sweets، handmade juices، local milk and traditional ice cream. Among the sweets، the contamination to coliforms was 11% higher than other bacerias، and accordingly in dairy products، the contamination to Escherichia coli 7. 9%، Escherichia coli in juices 15%، coliforms in fruits and vegetables 3. 6% and Escherichia coli in protein foods have shown the highest contamination. Noting the findings in this study، in order to prevent the microbial contamination in foods، personal awareness، observing the sanitation، surveillance in preparation، transportation، storage and supply of food are all of great necessity.

This study aimed to determine effectiveness of Satureja khuzestanica extract on Leishmania major in vitro. In present study standard strain of Leishmania major with MRHO/IR/75/ER international code was used that previously had been cultured in NNN medium. This parasite was transferred from NNN medium to RPMI 1640 medium. Then at logarithmic phase, certain numbers of parasite were taken from this medium and were added to cell culturing plate. Then effect of 250 , 500 , 1000 mg /ml extract of Satureja khuzestanica on Leishmania major promastigotes were examined in 24 and 72 hours and the effect of these concentrations were compared to glucantime. Additionally, effects of concentrations such as 250, 300, 350, 400, 450 mg / ml of Satureja khuzestanica extract was examined to obtain its minimum effective concentration. In the study and comparison between extract and glucantime with concentrations 250 , 500 , 1000 , mg /ml , after 72 hours , decrease in promastigote population were compared to untreated control in these concentrations and for Satureisa khuzestanica extract were 56.14% , 77.19% and 77.19% , respectively while for glucantime it was 19.29 , 24.56 , 33.33% respectively. Minimum effective concentration of this extract was up to 250 mg /ml . Satureja khuzestanica extract has an acceptable effect on Leishmania major in in vitro conditions in comparison with glucantime