BIOLOGICAL JOURNAL OF MICROORGANISM
Year:2018 | Volume:7 | Issue:25 |Papers Count:10

Introduction: Organophosphorus pesticides are used extensively in agriculture. Most of them are released into the environment and have harmful effects on the health of ecosystems, wildlife and humans. Due to the increase of the salinity in the agriculture, especially drainage waters and the need for cleaning and reuse of the water due to water shortages, there is an increased demand for new treatment techniques. Bioremediation is the efficient and environmentally friendly way and can be used to remove these contaminants.Materials and methods: Halophilic bacteria that have the ability to use organophosphorus pesticide chlorpyrifos as the sole source of carbon, were isolated through targeted enrichment. Based on the higher growth and tolerance in the presence of the pesticide, one isolate was selected. The ability of the selected strain to degrade chlorpyrifos was examined by gas chromatography-mass spectrometry analysis. The strain was identified by molecular method. To determine the optimal growth conditions, as an indicator of optimal pesticide removal, factors such as temperature, pH, concentration of salt and chlorpyrifos in the presence of pesticide (sole source of carbon) were examined.Results: The selected isolate named CDB5 showed 25.23% removal of chlorpyrifos in the basic conditions without addition of growth factors in 10 days. The molecular identification revealed that this halophilic strain belongs to the genus Halomonas sp. Investigation of the effect of factors in the presence of chlorpyrifos as the sole source of carbon showed that the strain has the highest growth at temperature 35℃, pH7, salt concentration of 10% and the chlorpyrifos concentration of 600 mg/l.Discussion and conclusion: Halophilic bacteria due to compatibility with the salty condition, can be a good option for the removal of organophosphorus pesticides in the contaminated salty environments.

Introduction: Some of the bacteria having merA gene coding mineral mercury reducing enzyme, has genetic potential of Hg removing via reduction of mineral mercury and transformation of that to gas form and finally bioremediation of polluted area. The aim of this study is the isolation of merA gene from resistance bacteria and cloning of that into suitable expression vector and then the environmental bioremediation by the transformation of bacteria with this vector.Materials and methods: A number of bacteria were collected in contaminated areas with mercury in order to isolate merA genes. Polymerase chain reaction had done on the four bacterial genomes including Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens and Escherichia coli using the specific primers in order to detect merA gene. For cloning, the primers containing restriction enzyme sites are used, merA gene was isolated and amplified. The amplified fragments were cloned in the expression vector pET21a+and via heat shock method were transformed into E. coli TOP10 competent cell. For clustering of genes, Mega software version 4 was used and bioanformatic studies were achieved for predicted enzyme.Results: merA gene with 1686 bp in length was isolated from K pneumoniae and E. coli. Recombinant vectors in transgenic bacteria were confirmed by various methods and finally were confirmed by sequencing. The result of clustering these genes with existence genes in NCBI showed high similarity.Discussion and conclusion: The existence of merA gene in bacteria that adapted to Hg pollution area is because of resistance, so with cloning this gene into suitable expression vector and transformation of susceptible bacteria with this vector ability of resistance to Hg in bacteria for bioremediation could be given.

Introduction: Infection after the surgery is one of the problems of bone scaffolds implants which is normally treated by systemic administration of antibiotics. But due to the poor blood circulation in bone tissue, large antibiotic doses are needed which lead to further drawbacks to renal and hepatic systems.Materials and methods: In this study, the effect of zinc oxide addition on antibacterial behavior of hydroxyapatite -Poly lactic-co-glycolic acid scaffold was evaluated. The synthesized composite was characterized by X-ray diffraction, scanning electron microscopy equipped with elemental analysis and Fourier transform infrared spectra. In order to determine the antibacterial activity of the fabricated scaffold, Staphylococcus aureus (ATTC 25922) and Escherichia coli (ATTC 25923) were used as test microorganisms.Results: The results showed that Hydroxyapatite- Poly lactic-co-glycolic acid scaffold did not make inhibition zone in culture medium but the modification of Hydroxyapatite- Poly lactic-co-glycolic acid scaffold’s surface by zinc oxide particles caused Hydroxyapatite- Poly lactic-co-glycolic acid- zinc oxide scaffold to have antibacterial inhibition zone of 12 and 20 mm for Escherichia coli and Staphylococcus aureus, respectively.Discussion and conclusion: This study revealed that the addition of antibacterial agent to applicable bone tissue engineering scaffolds could be considered as an appropriate way to prevent the growth of infection at the scaffold sites.

Introduction: The bean common blight caused by Xanthomonas axonpodis pv. phaseoli is one of the most important pathogens of bean, which is a serious problem to produce this crop in western regions of the country. Due to the severe damage of this pathogen, using fungal and bacterial bio-control agents can be as an efficient way to reduce the damage of disease on bean. The aim of this study was to evaluate the controller effects of fungal and bacterial biological agents including Trichoderma harzianum, T. virens, Bacillus subtillis and Pseudomonas fluorescence in laboratory and greenhouse conditions on bacteria of bean common blight.Materials and methods: In order to study the effects of biological agent against Xap, in the first stage, was to investigate the percentage growth inhibition of Xapby biological agents under laboratory conditions. In the next step, the interaction of biological agent and pathogenesis bacteria on bean plant was evaluated in a completely randomized design, four replications and biological agent’s treatments are under the greenhouse conditions. Indices such as root and shoot fresh weight, root and shoot dry weight, height roots and stems of beans and disease severity were measured to analyse the control power of the biological agents.Results: In laboratory conditions, fungal biological agents of T. harzianum with an average diameter of inhibitor halo of 42 mm and inhibiting 56.67% of the growth had highest controller effect on pathogenesis bacteria. However, in greenhouse conditions, P. fluorescence bacteria had better performance and all plant indices under this treatment showed a significant growth. The combined treatment of P. fleurescence+T. virens was the best treatment in this experiment with reducing 79.4% of disease symptoms. Treatments P. fleurescence +T. harzianum and B. subtillis +P. fleurescence with amount of 69.6 and 55.9% reduced the symptoms, respectively, and are in following levels.Discussion and conclusion: Therefore, the use of biological agents can largely reduce the bean common blight, so that it can be an efficient and environmentally friendly method used.

Introduction: In sustainable agriculture, biological control is an important alternative to control various plant diseases, in particular, pathogenic fungus that causes the most economic damage to agricultural products in the world. Each soil species bacterium has unique specified features and abilities. Alternaria sp has specific herbal poisons that lead to diseases in them. Biological control of fungal diseases in agricultural products across the world has been done in recent years using fungi and soil antagonist bacteria. Some bacterial isolates that produce chitinase enzymes fight with fungal pathogens.Materials and Methods: To achieve an antagonist chitinolytic bacteria against Alternaria alternata fungal, screening soil species bacterium that produce chitinase of some urban and agriculture soil samples of Qazvin were carried out.Results: In this study, five different strain of chitinolytic bacteria were found, two strains of Pseudomonas nitroreducens in vitro and one strain (AHH4), they had the ability to destroying fungal pathogen Alternaria sp in the farm. as the presence of high concentrations (0.05 OD600 and above) of the bacteria, A. alternata fungus growth stopped completely.Discussion and conclusion: However, one of them, P. nitroreducens (AHH4) could control the fungus at in vitro and invivo and inhibit the growth of fungus. So P. nitroreducens (AHH4) chitinolytic bacteria has efficiently effect on inhibit A. alternata fungal growth. As the presence of high concentrations (0.05 OD600 and above) of the bacteria A. alternata fungus growth stopped completely. The isolate AHH4 was submitted to NCBI/DDBJ/EMBL as KR905055 accession number.

Introduction: a-Naphthol is a two-ring aromatic hydrocarbon that is a toxic compound for all organisms in different ecosystems. Bioremediation technology for remediating PAH-contaminated sites has been proposed to be an efficient, economical and versatile alternative compared with physicochemical methods.Materials and Methods: In this study, the basal salt medium was prepared and then a-Naphthol was added with the concentration of 100ppm. a-Naphthol was a sole source of carbon for the growth of bacteria. Eventually, the medium was inoculated with the soil samples collected from polluted region and incubated for six weeks. Bacteria were isolated using double-layer BSM-agar containing the a-naphthol concentration of 200ppm. The degradation rate of a-naphthol and the other PAHs were determined using HPLC and the effective isolate was finally identified using biochemical and molecular methods.Results: In this study, two isolates (N1 and N2) were isolated that were able to utilize a-Naphthol as a sole source of carbon. The isolate N1 could degrade α-naph thol by 80.5%. Moreover, it was effectively able to degrade the other PAHs than the isolate N2, therefore, it was selected as an efficient isolate. The isolate N1 was identified as Psuedomonas putida UW4 with respect to its 16S rDNA sequence and using biochemical tests.Discussion and conclusion: The isolate N1 could degrade a-naph thol by 80.5% from BSM medium at 30° C, pH 7.0 and the a-naph thol concentration of 100ppm in fifteen days of incub a tion. According to the results, the isolate N1 can remove a large amount of the a-naph thol from BSM medium under the mentioned conditions and it is possible that under a similar situation the isolate N1 can remove a large amount of a-naph thol.

Introduction: Diseases caused by opportunistic pathogen Candida albicans are usually treated with antifungal drugs, but treatment failure is not uncommon especially in profoundly immunocompromised hosts. The aim of this study was to compare erg gene expression profiles of Candida albicans treated with Thymus vulgaris extracts alone and in combination with Mentha spicata.Materials and methods: In this cross- sectional study, using volume based analyses we have conducted a gene expression profiling of ERG11 gene in C. albicans treated with Thymus vulgaris extracts alone and in combination with Mentha spicata.Results: Analysis of gene expression profiles revealed the decrease of ERG11 in C. albicans treated with Thymus vulgaris extracts in combination with Mentha spicata. Incubation with Thymus vulgaris and Mentha spicata extracts alone, however, resulted in a decrease in ERG11 RNA levels less than combination.Discussion and conclusion: These data suggest a common mechanism to find the probable targets e.g., in response to ergosterol depletion in C. albicans treated with Thymus vulgaris extracts alone and in combination with Mentha spicata.

Introduction: Bacillus thuringiensis, is a Gram-positive spore-forming bacterium that produces crystalline parasporal protein (Cry) during sporulation. Some of these Cry toxins do not show cytotoxicity against insects but they are capable to kill some human and animal cancer cells. The aim of this study was to verify whether cytocidal parasporal of B thuringiensis strains have immunostimulatory activity on human peripheral blood mononuclear cells (PBMNC) and to evaluate the ability of IL-2 and IL-5 production.Materials and methods: B. thuringiensis toxin with cytocidal activity was isolated and treated with proteinase K. PBMNC was cultured and treated with activated crystal proteins. We evaluated the ability of different cytokines production with Flow Cytometry.Results: In this study, immune stimulatory toxins Cry1 were distinguished. This toxin can stimulate production of cytokines IL-2 and stop production of IL-5.Discussion and conclusion: According to anti-cancer effect of B. thuringiensis toxins and also immune stimulatory effect, with more research these toxins can be introduced as immunotherapy drug in cancer treatment.

Introduction: Phosphate solubilizing bacteria play roles in phosphate solubilizing from mineral sources. These bacteria with different mechanisms make it soluble, some parts of solubilized P were absorbed in their biomass and the other parts, released in the soluble form which can be used by other organisms.Materials and methods: In this study, 24 bacterial isolates belonged to different genera such as Azotobacter, Pseudomonas, Rhizobium, Beijerinckia, Klebsiella, Agrobacterium, Alcaligenes, Sphingomnas, Microbacterium and Citrobacter were examined to determine solubilized P from two sources of phosphate (TCP and RP) in Sperber medium. This research was carried out in a complementary random design with three replications. At the end of incubation time, solubilized P in supernatant, amount of P in biomass and total solubilized P were measured.Results: The results showed that isolates are efficient in solubilizing P from TCP than RP. By decreasing pH, solubilized P was increased (r=0.775, p<0.01) and it followed by increasing EC (r=0.789, p<0.01). Highest P in supernatant was measured in media inoculated with Pseudomonas, Azotobacter and Agrobacterium. Maximum absorbed P in biomass was determined in Agrobacterium and Citrobacter isolates. However, total solubilized P including (phosphorus in supernatant and phosphorus in biomass) were the highest in Agrobacterium and Citrobacter (527.4 and 460.8 mg/l, respectively). Highest bio-absorption percent (P biomass/ P added) was recorded in Klebsiella sp.4A-1 (44.44%) and Agrobacterium sp.22SP-1 (42.33%), and maximum P solubilization rate (P supernatant/ P solubilized total) was observed in Pseudomonas sp.34SPIII (0.51) and Azotobacter chroococcum 44SP-2 (0.5).Discussion and conclusion: In most researches, solubilized P which is present in supernatant takes more attention but phosphorus in biomass is ignored which can be mineralized and available with a delay. This study showed that most parts of solubilized P were measured in microbial biomass. Hence, attention to this criterion could help us to select efficient PSB.

Introduction: From an industrial application or commercial point of view, glutamic acid is one of the most important amino acids and its microbial production has been reported from some bacteria. Regarding the role of probiotics to modulate human health and the ever-increasing demand of prebiotics in the food industry, in the current study, production of glutamic acid and folic acid from three probiotic bacteria (Bifidobacterium, Bifidobacterium bifidum, Sporolactobacillus) was evaluated for the first time.Materials and methods: MRS broth and exclusive media was used for probiotic culture. The glutamic acid was identified using thin-layer chromatography and folic acid production was measured by folate kit. Each bacterium in terms of quality and quantity were measured by high pressure liquid chromatography.Results: Production of glutamic acid confirmed is based on the thin layer chromatography analysis and high pressure liquid chromatography results. In addition, it was observed that all three probiotics produce folic acid. The prevalence of folate in Bifidobacterium was measured as 315 mg/ml that was more than two other bacteria.Discussion and conclusion: To the best of our knowledge, this is the first report of microbial production of glutamic acid and folate from the probiotic bacteria. These beneficial bacteria can be used as a good source for mass production of these valuable compounds.