Background & Aims: Dimethoate as an organophosphorus compound is commonly used for crop production which is neurotoxic in human. PSEUDOMONAS family harbor organophosphate degrading plasmids have been known as tools for cleaning environmental pollutions.Materials & Methods: PSEUDOMONAS Putida was isolated from contaminated soil being identified and optimally cultured in mineral medium and was enriched with dimethoate. Bacterial utilization of dimethoate was determined by acetylcholine esterase inhibition (toxicity). The degrading plasmids for hydrolytic enzymes were deleted by acridine orange and transferred from resistance to sensitive strain.Results: Dimethoate was optimally utilized at 0.8 g/L concentration in mineral solution. The maximum dimethoate concentration tolerate by this bacterium was up 4.0 g/L in nutrient broth. The bacterial growth increased more than 2 folds in medium containing dimethoate in comparison with inorganic phosphate. Total proteins’ content that increased up to 357 mg/L was used as a known neuro-toxicity marker. Acetylcholine esterase activity was decreased by dimethoate in concentrations of 0.2-2.0 g/L in linear order but the inhibitory effect of dimethoate residue decreased 50-95% in P. Putida culture containing 2.0 g/L dimethoate after 48-96 hrs respectively. The resistance strain was lost degrading plasmids by acridine orange. The resistance plasmids were also transferred to sensitive strains.Conclusion: The mentioned plasmids express organophosphorus degrading enzymes and are supposed as effective techniques for cleaning of organophosphorus compounds as anti-nerve poisons and may be applicator of adverse effects of organophosphoruse compounds by modern technologies.

Desulfurization of thiophenic compounds is one of the important issues in refineries and environmental pollutions control. A bacterium was isolated from MTBE enriched soil was able to desulfurize of the thiophene. It was identified as PSEUDOMONAS stutzeri based on phylogenetic analysis of 16S rRNA gene sequence. Desulfurization reactions from thiophene as the model of thiophenic compounds in aqueous phase by resting cells of this strain carried out and the concentration of thiophene was determined by UV-visible spectrophotometer in 230 nm wavelength. The results showed that the reduction of thiophene was 95% (from 12.4 mM to 0.3 mM) after 15 hours. Gas chromatography analysis showed the same results of thiophene desulfurization. Furthermore, The desulfurization activity of resting cells in a biphasic system containing crude oil by determination of released sulfate content turbidimetrically with BaCl2 was investigated.

PSEUDOMONAS syringae is one of the phytopathogenic bacteria with larg genetic, physiological and biological variations. In this study, resistance of P.s. pv. syringae and P.s. pv. tomato were examined under both dry and humid conditions.P.syringae was susceptible to drought and it did not survive after three hys on the surface of teflon, filter paper and surface of tomato seeds. Various inoculums used that were under relatively low humid condition caused rapid death of bacterial cells. Hrp genes had an important role in multiplication of bacteria, however, no major role was observed on the survival of bacteria on seed and inert materials. In contrast, after germination of seed and development of seedling, the population dynamism of hrp mutant strains was significantly lower than those of wild strains. Seed infestation by P.s. pv. tomato occurred at low frequency even on heavily infected plants. The results of this study show that survival of P.syringaefrom one year to another can occur through other ways such as, soil infection and plant debries.

Proton gradient – dependent efflux pumps play important role in multidrug resistance (MDR) in PSEUDOMONAS aeruginosa. 23 MDR strains were selected from 104 clinical isolates of P. aeruginosa and screened for resistance to ceftazidim, ceftriaxone, ciprofloxacin, ofloxacin, amikacin, gentamicin and ethidium bromide by determining MICs. The MICs of EtBr and antibiotics were also measured in presence of protonophore, carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Active efflux was assessed using ethidium bromide accumulation assays. Drug accumulation studies for fluoroquinolones were performed to determine the drug specificity of efflux. PCR was used to identify the mexAB-oprM gene in clinical isolates of P. aeruginosa. CCCP reduced the MICs of antibiotics at least in 1 dilution. Ethidium bromide accumulation assays confirmed the presence of proton gradient–dependent efflux mechanism in clinical isolates of P. aeruginosa and accumulation assays of fluoroquinolones showed that efflux systems in this bacterium extrude the structurally and functionally dissimilar antimicrobial agents. PCR demonstrated that 17% of clinical isolates of P. aeruginosa had the mexAB-oprM genes on the chromosome. This study indicates the presence of other RND efflux pumps, in addition to MexAB-OprM in multidrug resistance in clinical isolates of P .aeruginosa.

Epiphytic and endophytic colonization of some PSEUDOMONAS syringae pathovars in leaves, stems and roots of tomato (Lycopersicon esculentll/l1cv. Cannery Row) was studied. Surface disinfestation with chloroform revealed that the chemical is a potent surface sterilant but would not penetrate into the natural openings present on plant tissue surfaces. Hence chloroform appeared to be harmless to massive bacterial populations present in such area as stomata and lenticels. This chemical was found suitable for surface disinfestation in studies dealt with endophytic colonization. Plasmid pLA LacZ was introduced via triparental pairing into wild type and hrp mutant strains of p.s. pv syringae, p.s. pv tomato and p.s. pv phaseolicola. Tamato cv. Cannery Row seedling were inoculated with the wild type and mutant strains of P.syringae. Microscopic examination thin sections of the inoculated but symptomless tomato organs and tissues revealed that bacterial colonization occurred mostly endophytically. P.syringae cells were observed among paranchyma cells and in vascular tissues of inoculated plants. These sites appeared to be more suitable for colonization P.syringae.

This project was conducted to determine the effect of PSEUDOMONAS fluorescence bacteria on increasing the growth rates of some species of algae namely Chaetoceros Sp., Skeletonema sp., Tetraselmis sp., Chlorella sp. In this order, the mentioned bacteria were extracted by separator and Zobell 16E media from prawn broodstock ponds, then purified and mass cultured. The algae selected mass, were cultured in Conway media and then these bacteria were investigated at the blooming phase in the several experiments of various treatments in combined culture method. The results revealed that the mentioned bacteria could apply as a partial substitution body of aglae media and it could be used as a new media in various percentages. The results indicated, the very positive effect of bacteria on cultured algae. Therefore, PSEUDOMONAS fluorescense can be used in algae cultured in 50-150 mg\lit density as a new method for algae culture. This bacterium Could be a new media for Chaetoceros sp., and Tetraselmis sp., but for Skeletonema sp., other percentages of media should be used.

Background: PSEUDOMONAS aeruginosa is a gram negative non facultative bacterium and one of the members of normal flora in different sites of body in healthy humans. This bacterium can resist in fluids and hospital environments for a long time.PSEUDOMONAS aeruginosa has two systems for glucose uptake: a low affinity oxidative pathway and a high affinity phosphorylative pathway. The orf BCD genes are located over two million base pair upstream of the genes involved in the high affinity uptake system. Although the role of these genes are unknown by now, they may have a role in regulation of glucose uptake. In the present study, the role of orfD gene in glucose uptake in P.aeruginosa has been investigated.Method: orfD fragment were cloned in pUCP20 as vector and the recombinant plasmid transferred into WMA200 strain of P.aeruginosa, a mutant strain of P.aeruginosa with a chromosomal deletion of orfBCD. So we compared the rate of glucose uptake by P.aeruginosaWMA200, P.aeruginosaWMA200/pUCP20/orfD and P.aeruginosa H103 as wild type strain of P.aeruginosa by using labeled glucose under conditions at low substrate concentration and low cell density.Results: Carbohydrate uptake patterns differed considerably among three strains. The wild type is able to uptake glucose at a faster rate than the mutant; however, the mutant complemented with orfD shows an intermediate uptake comparing to the wild type and the mutant.Conclusion: orfD gene has an important role in carbohydrate uptake in P.aeruginosa strains however further studies are required to determine the involved mechanism.

PSEUDOMONAS syringae is a phytogenic bacterium with a wide host range. The biology of this bacterium consists of two phases. The first phase is the indication of disease on the host plant which generally appears in the form of necrosis on the aerial parts of plant (pathogenicity phase). The second phase is a rapid multiplication of bacteria on the aerial surface of the plant without inflicting any defense response (epiphytic phase). In this study, the impact of pathogenic virulence genes of agress, dsp, ice, cor and hrp genes in the epiphytic process of PSEUDOMONAS syringae on resistant and sensitive varieties of tomato is examined. The population dynamism of bacterial colonization on the root, stem and leaves was studied. The results indicated that the hrp genes system (hypersensitive reaction and pathogenicity) in PSEUDOMONAS syringae pv. tomato, P. s. pv. syringae and P. s. pv. phaseolicola and the coronatine gene system in P. s. pv. tomato are necessary for colonization on both host and non-host plants. The mutants isolates of hrp and cor compared with wild isolates could colonize at a lower level on all parts of the plant. In contrast, the ice (Ice nucleation), agress (Agressivity) and dsp (discase specific) gene systems had no significant impact on the epiphytic colonization of P. s. pv. syringae. However, under in vitro conditions no significant difference was observed among the wild type isolates and their mutants in king B medium in the bioscreen machine. It is concluded that the lower multiplication of P. syringae mutants in plant is due to the plant-bacteria interaction.