فهرست مطالب غلامحسین ابراهیمی پور

In the last few decades, Escherichia coli strains producing extended-spectrum beta-lactamases (ESBLs) have increased and are now considered a major problem in hospitalized patients. The aim of this study was to investigate the prevalence of blaCTX-M and blaTEM genes in Escherichia coli with multiple drug resistance.

This study was conducted from October 2021 to May 2022. The research site included the microbiology laboratories of Golestan, Imam Khomeini, and Shahid Beqai hospitals where isolates suspected of Escherichia coli were isolated from urine culture samples of patients with urinary tract infection. All Escherichia coli samples were identified by conventional biochemical and molecular methods. The antibiotic sensitivity of the isolates was determined by disk diffusion method. Then, in order to finally confirm the presence of blaCTX-M and blaTE genes, PCR method was used.

Out of the 160 bacterial isolates examined, 138 (86.3%) showed multidrug resistance (MDR). The highest and lowest percentage of resistance was related to Amoxicillin-Clavonic acid (84.1%) and Meropenem (5.8%), respectively. Based on the combined disk method, 96 isolates (69.6%) were positive for Beta-lactamase enzymes (ESBLs). Among the 96 ESBL-positive isolates, 85 (88.5%) and 38 (39.6%) carried blaCTX-M and blaTEM genes, respectively.

Conclusion:

 Given the significant prevalence of Escherichia coli strains that are resistant to multiple drugs and carrying ESBLs beta-lactamase genes in hospital, there is a need for effective surveillance measures to prevent the further spread of drug resistance in these isolates.

L-asparaginase can be effectively used for the treatment of cancers, such as acute lymphoblastic leukemia, melanosarcoma, and lymphosarcoma. Bacterial sources contribute to the mass production of L-asparaginase.

In this study, a novel L-asparaginase-producing bacterium was isolated from the soil of East Azerbaijan Province. Totally, 4 isolates were shown to have high L-asparaginase activities by using Nessler's reagent through the spectrophotometric method. The strain with glutaminase-free L-asparaginase activity was chosen for further studies. The isolated strain was identified via microscopic and biochemical tests. The growth conditions, including nutritional factors (carbon and nitrogen sources) and physical parameters (pH and temperature), were assayed and optimized for maximum L-asparaginase growth rate and production.

B. subtilis as a potential microorganism was isolated, screened, and identified for the production of L-asparaginase. The optimization study revealed that maximum L-asparaginase could be produced at pH 7.0 and temperature of 37oC in the presence of 1% whey as the most suitable carbon source and 0.2% asparagine as a nitrogen source.

The mentioned organism could be exploited for industrial production of L-asparaginase to be eventually utilized in cancer therapy. Under the obtained optimal conditions, L-asparaginase production was enhanced up to 2-fold (7.8 U/ml).

Bread currently accounts for the majority of the population's diet;and a strict lifelong gluten-free diet is currently the only available treatment to cope with gluten intolerance. Therefore, food experts are constantly finding ways to produce and improve the quality of gluten-free bread. This study was performed to qualitatively evaluate the effect of aspergillopepsin enzyme on degradation of gluten during in wheat dough fermentation. The qualitative effects of aspergillopepsin expressed in bakery yeast on gluten protein and on the rheological properties of wheat flour dough were studied and the rheological properties of the dough were investigated by a rheometer. In addition, initial flour tests were evaluated such as measuring the amount of crude fiber, fat, moisture, wet gluten, protein, pH, ash. Samples prepared with engineered yeast dough had low elasticity, no gas production, relatively loose texture and no specific odor, which confirmed that the gluten network was not formed. Finally, the study of the rheological properties of the dough showed that this enzyme affects the texture of the dough. For this purpose, here we investigate the effectiveness of aspergillopepsin enzyme have been shown to effectively Therefore, the feasibility of producing high-quality bread from wheat flour treatment with aspergillopepsin has been shown

Polycyclic aromatic hydrocarbons are one of the most important environmental pollutants. Bioremediation using microorganisms is a cost-effective and safe method for the removal or conversion of these pollutants to less toxic substances. This study aimed to isolate and introduce fluorene-degrading microorganisms from the southern coast of the Caspian Sea. The mixed microbial culture enrichment and isolation was done in salt-based culture medium containing fluorene. The qualitative analysis of fluorene degradation in the solid basal salt medium was investigated. The rate of fluorene removal by the isolated mixed microbial culture was also determined using gas chromatography in a liquid salt base medium. The molecular identification of the fungal and bacterial isolates was performed using the sequential analysis of the ITS protected region and 16S rRNA sequencing, respectively. The mixed microbial culture including bacterial isolates (belonging to the genus Pseudomonas, Acromobacter, Chryseobacterium, Microbacterium, and Rhodococcus) and fungal isolate (belonging to the genus Fusarium) was enriched and isolated. Chromatographic analysis showed that the mixed microbial culture was able to degrade 87% of fluorene (200 mg / l ) in a basal salt medium at 30 °C, pH 7 and 7 days of incubation. According to the results, the mixed microbial can remove a large amount of fluorene from the basal salt medium under the mentioned conditions and it is possible that under a similar situation, it can remove a large amount of fluorene from the contaminated area through bioremediation.

Although biosurfactants have great advantages over chemical surfactants, their wider industrial applications have been constrained by their relatively high production cost. Using renewable, sustainable and cheap substrates such as different industrial by-products and wastes maybe decrease biosurfactant production costs. Since in different countries, there are a variety of by-products and wastes so use of these substrates rely on their types and concentrations in countries. In addition to hydrocarbon compounds, molasses has been considered as a dominant by-product in Iran. In this study, among 16 crude oil degrading isolates, strain Pseudomonas aeruginosa ZN was selected as an efficient biosurfactant producer by screening methods for detection of biosurfactant producing bacteria. For investigation of molasses concentrations effect on bacterial growth and biosurfactant production, a wide range of molasses concentrations from 2-12% (v/v) were used. This strain was able to grow and produce biosurfactant in all range of molasses concentrations while the best concentrations were 4-6%. Also, at the optimum molasses concentration, reduction of surface tension from 70 to 32-34 mN/m was observed. The concnetrations more than these values decreased the growth and production process. Acid precipitation and solvent extract (ethyl acetate: hexane) methods were carried out for recovery of biosurfactant from the culture broth, then results of spraying on developed TLC and staining fermentation broth without bacterial cells showed the two produced biosurfactants were glycolipid.

 Asparaginases are known to be the cornerstone for the treatment of acute lymphoblastic leukemia (ALL) and are used for treatment in all pediatric regimens as well as in the majority of adult treatment protocols. Clinical hypersensitivity reactions against commercially available asparaginase have resulted in the failure in the treatment of ALL in more than 60% of cases. Thus, it is required to search for serologically different asparaginases from new organisms for patients exhibiting sensitivity to one formulation of asparaginase.

   The experiments were conducted in 250 mL flasks containing 100 mL of M9 broth medium and incubated at 35˚C for 48 h with shaking 100 rpm. The bacterium produced an extracellular asparaginase enzyme in which a heavy metal-rich medium was influenced—considering that this idea, enzyme activity was marked at the presence of metal salts such as FeCl3, ZnCl2, CoCl2, MgCl2, CaCl2, CuSO4, KCl and NaCl with the different concentrations as 0-3% W/V.

   In this research, we isolated a bacterium that belonged to staphylococcus species named strain MGM1 and deposited to NCBI by accession number of KT361190. The results showed that Na+, Fe2+, and K+ were inducted to enzyme production, and Zn2+ had no effects, while Cu2+, Ca2+, and Mg2+ inhibited enzyme activity when their concentrations increased up to 1%. 

This study aimed to investigate the effects of different ions on the activity of the enzyme in the blood and fluid of the body. Such compounds are vital elements in the blood, and therefore, their effect on the enzyme is very important, So This experiment suggests that asparaginase could be affected by the metals.

One of the important findings in the pharmaceutical and medical industry is the use of the asparaginazase enzyme as an anticancer drug. The asparaginase enzyme, hydrolyzing the amino acid of asparagine, reduces this amino acid in the blood and causes the death of cancer cells. Today, the enzyme is used to treat various types of leukemia, particularly acute lymphoblastic leukemia, lymphosarcoma and non-Hodgkin's lymphoma. Despite the widespread use of asparaginase in the pharmaceutical and medical industries, there are major problems with the use of this enzyme, including immune system stimulation, response to the enzyme and the enzyme's glutaminase activity. It has been shown to be part of the side effects due to the glutaminase present in asparaginase. Extensive research is under way to find new sources of enzyme-producing with fewer immunological properties and side effects, and has brought hopes in this direction. In Iran, research has also been conducted over recent years to find new sources of enzyme production with new features and less side effects, and it is hoped that this research will reach the clinical and industrial stage. This paper is a review of the mechanism of enzyme activity, enzyme applications in various industries, sources of asparaginase production, and how it is produced and purified.

Future studies can introduce new asparaginase with potential benefits for patients. However, the search for new sources of enzyme-producing microorganisms with higher therapeutic potential is still ongoing around the world.

In recent years, electrochemical detection techniques have proved quite promising since they are simple, fast and cost effective. Up to date, some electrochemical biosensors based on enzymes and microorganisms have been fabricated for the detection of phenol as a priority pollutant listed by the United States Environmental Protection Agency (USEPA). MWCNTs have been widely considered as attractive materials due to their high electrical conductivity, chemical stability and extremely high mechanical strength. The presented work includes the development of a fast, sensitive and miniaturized microbial conductometric biosensor for the determination of phenol based on the cells of Pseudomonas sp. (GSN23) and modified microelectrodes with MWCNTs.

Cells of Pseudomonas sp. (GSN23) were grown in the presence of phenol as the sole source of organic carbon and adapted cells were immobilized on the surface of gold interdigitated microelectrodes. Carbon nanotube (CNT) - modified microelectrodes were also prepared to test nanoparticle effect on the efficiency of biosensor performance.

From the results obtained with conductometric measurement, sensitive detection of phenol from 1 to 300 mg.L-1 (10-3187 µM), was estimated. Furthermore, substrate specificity and operational stability were investigated. Discussion and

The proposed system does not require any complex immobilization procedures and showed the linearity and repeatability with a high operational stability. The use of optimum amounts of MWCNTs and phenol adapted bacteria provide better sensor sensitivity by promoting the ions transfer within the structure of the biosensor

Phenol is considered to be an important pollutant in the environment and is steadier than other aromatic compounds in industrial treatment. There are several methods for detecting phenol in the wastes. In spite of the high accuracy of these methods, they are time consuming and complex. The utilization of enzymatic biosensors for the identification of phenolic compounds is one of the options and successful techniques. However, the weaknesses of enzymes and high financial expenses cannot be ignored. One of the alternative solutions to overcome the shortcomings of working with enzymes is the utilization of microbial cells in biosensors. In this study, microbial cells were used to design a reasonable and accurate biosensor.

In this survey, designing of a biosensor was examined using a phenol consuming bacterium. Pseudomonas.GSN23 was acclimatized to high phenol concentrations and immobilized by forming physical and chemical links on working electrodes (glassy carbon and gold interdigitated microelectrodes).Two electrochemical methods (square wave voltammetry and conductometric) were utilized to measure the phenol.

In the presence of 1 gram per liter phenol, as the only source of carbon and energy, Pseudomonas. GSN23 consumed 73% of the initial phenol concentration at 32 hours and phenol consumed completely at 72 hours. This bacterium had positive and repeatable responses in conductometric method for phenol detection in the range of 1-300 milligram per liter. The phenol selectivity of the designed biosensor was estimated 5 times more than other aromatic compounds.

Microbial biosensors are practical, stable and resistant to the changes of the experimental media. In this study, Pseudomonas.GSN23 was utilized as a phenol consuming bacterium and by conductivity measurement; repeatable responses were acquired in detecting this contaminant.

Proteases are important industrial enzymes used in different areas of industry, mainly detergent, food and leather industries. In this study, novel alkaline protease-producing bacterium was isolated from Geinarje hot spring and examined for maximum protease activity to be utilized in washing-powder. The isolated bacterium was cultured in mineral salt medium including 2% Skim Milk. Proteolytic activity of supernatant was measured by caseinolytic method. The effects of pH, temperature, SDS, Tween 80 and EDTA on protease stability and activity were investigated. The detergent compatibility of protease was assayed. On the basis of phylogenetic analysis and morphological as well as biochemical tests, the isolate was identified as a new strain of Brevibacillus borstelensis capable of generating extracellular alkaline protease. The generated protease was determined as alkaline metallo-protease having high activity at 60 oC and pH 9. Moreover, the alkaline protease was stable in the presence of SDS, Tween 80 and H2O2. It is compatible with commercial detergents. Finding proteases capable of degrading proteins in extreme environment (i.e. alkaline pH, high temperature and presence of surfactants) is valuable in biotechnological and industrial practices. Therefore, it can be utilized in detergent formulation in the future.

L-asparaginase enzyme has various applications, particularly in medicine and food industry. Given some side effects and adverse possession of a minor amount of glutaminase activity, the search for new sources of microbes producing glutaminase-free L-asparaginase type II is underway. The present study aimed to isolate a bacterium from the Persian Gulf that produces glutaminase-free L-asparaginase type II. It is also aimed to measure the amount of this enzyme and the condition under which it increases. In order to assess the capability of extracellular asparagine production, the isolated bacteria from the seawater were cultured in M9 medium containing phenol red and asparagine. Those bacteria with positive asparaginase test were cultured in M9 medium containing glutamine and phenol red to assess their glutamine activity. The bacterium isolate producing asparaginase was identified using morphological and biochemical means and 16 SrDNA. L-asparaginase enzyme activity of the isolate was explored with a colorimetric method. The effect of anaerobic condition on the amount of L-asparaginase type II activity was explored by culturing under aeration condition and with no aeration. The result showed that the isolated bacterium was Rhizobium nepotum strain SHN1. The asparaginase enzyme activity and the specific activity of this bacterium were 0.467 IU/mL and 0.015 IU/mg, respectively. These characteristics increased to more than 50% in anaerobic condition. The results indicated that microbial flora from the Persian Gulf flora could be a remarkable source of glutaminase-free L-asparaginase enzyme.

Organisms in different environmental conditions express different genes, which result in different protein expressions. These changes result from the adaptation of the organism to environmental conditions such as the presence of toxic substances. This study aimed to investigate the changes in protein expression in Celeribacter persicus SBU1 isolated from Nayband Bay mangrove forests, cultured in the medium containing phenanthrene as the sole source of carbon and energy. For this purpose, C. persicus SBU1 was cultured on mineral salt medium containing phenanthrene and sodium acetate as treatment and control, respectively. After the extraction of total protein, changes in protein expression were evaluated by SDS-PAGE. Proteins were identified by MALDI-TOF-TOF MS. After evaluating changes in protein content, two bands which showed greater variation in comparison with the control treatment (increased protein expression) were detected. The identified proteins included one ligand-gated channel protein and one unknown protein. In general, the results of this study showed significant changes in the protein content of C. persicus SBU1 after using phenanthrene. The up-regulation of ligand-gated channel protein signified the role of this protein in phenanthrene molecules transport in and out of the cells.

Myxobacteria are soil bacteria that move by gliding and have an astonishing life cycle culminating in fruiting body formation. The myxobacterial strain no.118 was isolated from unexplored soil of Koohrang County, Chaharmahal-o-Bakhtiari Province and tested for potential antimicrobial activity against various human pathogens. On the basis of results, strain 118 significantly inhibited growth of E. coli andM. luteus therefore was used for further characterization. Analysis of morphological, biochemical and 16S rRNA gene sequence indicated that this strain belongs to the genus Myxococcus. In addition, neighbor-joining phylogenetic tree confirmed the relationships of this strain to other members of Myxococcus genera. In order to explore the potential bioactivities, extract of the fermented broth culture was prepared with organic solvent extraction method. The methanol extract was subjected to HPLC fractionation against sensitive pathogens. LC/MS analysis resulted in the identification of Myxothiazol and Althiomycinantibiotics in methanol extract of the strain no. 118.

Myxobacteria are Gram-negative Deltaproteobacteria with rod-shaped vegetative cells, aerobic organotrophs that exhibit unique group behavior. The myxobacterial strain Mx18Zk was isolated from intestinal tract of earth worm of GhaemshahrCounty in Mazandaranprovince and the extraction of the fermented broth culture was prepared with organic solvent extraction method. Methanol extract tested for potential antimicrobial activity against11 various human pathogens. Finally the rest of methanol extract fractionated by HPLC and tested again against sensitive pathogens. Strain Mx18Zk significantly inhibited growth of Escherichia coli, Staphylococcus aureus and Chromobacterium violaceum, therefore was used for further characterization. Analysis of morphological, biochemical, 16S rRNA gene sequence and phylogenetic tree indicated that this strain with 100 % homology belongs to the genus Corallococcus macrosporus . The methanol extract was subjected to HPLC fractionation against sensitive pathogens. The active extracts studied by LC-MS and its results compared by previously identified myxobacterial secondary metabolites deposited in Myxobase database of HZI. LC/MS analysis resulted in the identification of Myxochromids and unknown Myxovirescins, Myxalamides antibiotics in methanol extract of the strain Mx18Zk.
Discussion and On the basis of results, isolated strain was active against Escherichia coli, Staphylococcus aureus and Chromobacterium violaceum and100 % homology was belong to the genus Corallococcus macrosporus. LC/MS analysis resulted in the identification of Myxochromids and unknown Myxovirescins, Myxalamides antibiotics in methanol extract of the strain Mx18Zk.

The Stability of protease in organic solvent media has been widely discussed for more than two decades. Proteases can catalyze synthetic reactions in organic media, by this way solvent stabilities of proteases are very important. In this study, we reported a bacterium isolated from hot spring of Geinarje, Iran producing an organic solvent stable protease. Protease producing bacteria were screened on skim milk agar and the formation of a clear zone around the bacterial colony was investigated. Proteolytic activity was assayed by a modified caseinolytic method using casein as a substrate. The best alkaline protease producing bacterium was selected and identified on the basis of 16S rDNA gene sequencing and morphological and biochemical characteristics. The effect of organic solvents, temperature, pH, and NaCl on proteolytic activity were examined. According to phylogenetic analysis, morphological and physiological tests, isolated, the bacterium was identified as a new strain of Brevibacillus borstelensis. This strain was able to produce an extracellular organic solvent-stable protease with 0.53U/ml enzyme activity. After 2 hour incubation at 30°C the protease of Brevibacillus borstelensis AMN was active in wide ranges of organic solvents, and its activity was enhanced in the presence of 25% (V/V) isopropanol. The biochemical properties of the enzyme revealed that the optimal pH and temperature for protease activity were 9.0 and 60°C, respectively. Our finding indicated that these robust properties of protease, like outstanding activity and stability in organic solvents and alkaline medium, might be applicable for various industrial biotechnologies.

Seeping oil and oily waste into the seas can cause serious damage to aquatic life. These compounds tend to bioaccumulate and threaten human health, Therefore, it is important to develop efficient methods for the treatment of these compounds. In this study, sediment and water from different regions of the Persian Gulf (Bandar Abbas) were sampled and enriched in mineral salt medium. The most efficient crude oil degrading bacteria was purified and then identified by molecular (16S rDNA) and biochemical analysis. The Taguchi experimental design L16 (45) was used to optimize the biodegradation process of crude oil by the isolated strain. This investigation applied the parameters of pH, temperature, optical density and concentration of NH4Cl and K2HPO4. The results showed that isolated strain had 99% similarity to Alcanivorax dieselolei and named TA1. Temperature and pH had the greatest influence on crude oil biodegradation. Maximum biodegradation efficiency was predicted to occur at pH= 9, temperature = 35 ͦC, NH4Cl (g/L)= 1, K2HPO4 (g/L)= 0.25 and optical density (OD)= 0.1. Under these conditions more than 80% of crude oil was degraded. Due to high ability of isolated strain to degrade crude oil, the results of this study can be used in the bioremediation of petroleum contaminated soil in the studied area.

The emergence of drug resistant pathogens indicates the need to discovery of new antibiotics. In the search for a new antibiotic producing microorganism, an Alcaligenes faecalis subsp. faecalis strain was isolatedfrom oil polluted soils near Dezful. One factor at a time was used to find important variables in antimicrobial compound production and upon its result pH = 9, temperature 35 ˚C, NH4Cl 0.34%, sodium acetate 2% and K2HPO4 0.02% have greatest effect on production, respectively. Acetate and NH4Cl concentration, shaker revolution and fermentation time were selected for optimization by response surface method with central composite design. The best result achieved by sodium acetate 1.88%, NH4Cl 0.29%, shaker 3 rpm and fermentation time 6.7 day which had 47% higher production than one factor at a time method. Results also indicated strong interaction between some variables.

Organophosphate pesticides are used most commonly for domestic, commercial, and agricultural purposes and have been found to be highly toxic. In essence, bioremediation has become one of the most important tools for removing these compounds in the environment, considering its higher efficiency when compared with the physicochemical methods.
The biodegradation efficiency of two bacterial strains (i.e. Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2) were assessed. In order to evaluate Malathion biodegradation, each sample was cultured on mineral salts medium containing Malathion as a sole carbon source. Malathion biodegradation efficiency of the strains was monitored in different culture media. The ability of bacterial isolates to degrade Malathion was studied using gas chromatography.
Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were able to degrade Malathion. Biodegradation percentage in different treatments recorded were: BNA1 (33.88%), BNA2 (26.45%), BNA1Ӑ㛸 (46/96%), BNA1ㆯ鏁 (61.05%), BNA2ㆯ鏁 (40.17%), and BNA1Ӑ㛸욾 Tween (67.79%).
It could be speculated that the best degradation efficiency can be yielded using mixture of strains plus a surfactant. The results of this study can be used in the bioremediation of Malathion contaminate soil after doing the pilot experiments.

Background and L-asparaginase is a well-known enzyme that is used as one of the most effective anti-leukemic drugs. Considering that the asparaginases used as antitumor are bacterial-based enzymes, the aim of this study was to find indigenous potential bacteria producing asparaginase. The enzyme producing bacteria was isolated from the agricultural soils around Gharchak, Tehran province, Iran. Screenings were performed on nutrient agar and M9 agar, respectively. The most efficient bacterium having asparaginase activity was selected and identified by biochemical and phylogenetic methods. Asparaginase activity was assayed by Nesslerization method. Optimization of the enzyme production was conducted by assessment of some factors such as the effect of carbon and nitrogen sources, salt concentration, pH, temperature and agitation. The selected bacterium was identified as a strain of staphylococcus that was named MGM1.The optimal conditions for enzyme activity was obtained at following conditions: 1% glucose as carbon source and 0.5 g/l beef extract as nitrogen source, without salt (NaCl) at pH range of 7-8 with shaking 120 rpm at 35 ◦C. The optimal activity for the enzyme produced by MGM1 was similar to physiological conditions of human body, therefore, further studies on this enzyme would be of great value in finding a new efficient asparginase enzyme.

The major of this study was to isolate oil-degrading bacteria from soil contaminated with petroleum and examining the removal of hydrocarbons by these bacteria.
Oil-degrading colonies were purified from the samples obtained of around Ahvaz oil wells. Organic matter degradation was investigated with 1 g of crude oil in basal salt medium (BSM) as sole carbon source. The growth rate was determined through total protein assay and hydrocarbon consuming was measured through organic carbon oxidation and titration by dichromate as oxidizing agent.
Two potential isolates named S1 and S2 strains were screened and identified as Planococcus and Pseudomonas aeruginosa. As results for S1 and S2 could degrade 80.86 and 65.6% of olive oil, 59.6 and 35.33 of crude oil, while 32 and 26.15 % of coal tar were consumed during 14 days incubation.
The results of this investigation showed these indigenous strains high capability to biodegradation at short time and are desirable alternatives for treatment of oil pollutants.

In recent years, more attention has been devoted to herbal medicines. Up to now, many compounds with therapeutic effects has been extracted from the herbs. The aim of this study is to evaluate the antioxidant and the antimicrobial effect of Rumex Alveollatus L. and to partially identify the effective compounds in this plant. Extraction was performed by using maceration method for dried flower sample. Then, the antimicrobial effect of aqueous and ethanolic extracts on eight bacterial sp. and two fungi were tested using disc diffusion method. The antioxidant effect was also determined through ferric reducing potency and phosphomolybdenum followed by total phenol determination. Finally, partial detection of bioactive compounds was conducted using chemical and calorimetric methods. The results showed that ethanolic extract had the most antimicrobial effect; while aqueous extract weakly affected bacterial and fungal strains. Antioxidant experiments also revealed that ethanol extract had more antioxidant effects than aqueous extract. The most content of total phenolic compounds was found in ethanol extract. The results of the plant chemical determination showed the presence of flavonoids, alkaloids, anthraquinones, tannins, glycosides, and reducing sugars. Considering that few reports about the therapeutic effect of Rumex alveollatus L. has been published, this study could be considered as a valuable report about the important role of this plant on preventing infections and neutralizing oxidant agents.

The bacteria living in the specific ecological conditions are among the most promising antimicrobial producers. This study aimed at isolating antimicrobial producing bacteria from soils contaminated with crude oil. the samples were obtained from crude oil contaminated soils around Dezful located in Khuzestan province, Iran, and antimicrobial producing bacteria were isolated using disc diffusion and cross streak culture. Then, the best bacterium was selected and its antimicrobial potency was studied against indicator microorganisms. The isolate was also characterized based on biochemical properties and phylogenetic analysis. based on the results, the highest antimicrobial activity of isolated bacterium was related to Candida albicans, Aspergillus niger, Bacillus subtilis, E. coli and Klebsiella pneumonia. An intermediate effect was determined against Serratia marcesens and Staphylococcus aureus, whereas no effect was observed against three strains of Enterococcus. Using biochemical characteristics and phenotypic traits, the isolate was identified as Alcaligenes faecalis. given that the isolate has broad spectrum activity against a various range of microorganisms and in comparison with some antimicrobial compounds produced by other Alcaligenes species, it seems the novelty of this antimicrobial compound.

Bachground and most of environmental microorganisms have the genes resistance to antibiotics and metals. The aim of the current study was to survey resistance pattern to some antibiotics and heavy metals in three pseudomonas aeruginosa isolated from different ecological areas. first, the isolates were identified by biochemical methods and phylogenetic analysis. Then, the evaluation of antibiotic resistance was conducted by disc diffusion and that of Heavy metal resistant by agar dilution, in a range of 50-500 µg/ml. The results showed that all three isolates were resistant to beta lactam antibiotics. Although these isolates were highly resistant to heavy metals, no relationship was observed between ecological sources and the resistance pattern in ICT1 and Abt2 strains. However, strain Q isolated from digestive system of ParmacellaIberica showed high resistance to antibiotics and low resistance to heavy metals. given that environmental bacteria have a high potentiality for carrying resistance genes and this can be an advantage environmentally, they could be used to remove heavy metals from polluted areas. On the other hand, resistance genes medically are a concern due to probability of transferring to pathogen strains.

Hydrocarbons degradation is principally achieved by microorganisms in natural environments. The extent of hydrocarbons biodegradation is mainly conditioned by environmental factors and its success depends on the optimal condition for the crude oil degrading isolates. The aims of the current study was to isolate and identify crude oil degrading bacterium from surface sediments of Qeshm Island, Iran and to evaluate the efficiency of a statistically-based experimental design for the optimization of crude oil degradation performed by the isolated strain. Crude oil degrading bacteria were isolated by serial dilutions of bacterial consortium. In order to optimize crude oil biodegradation by isolated strains, Plackett-Burman experimental design was used to evaluate nine factors affecting crude oil biodegradation in twelve experimental trials. To observe the best yield in crude oil biodegradation, factors that had higher effects were considered for the next stage in the biodegradation optimization process using the Taguchi experimental design. A gram-negative bacterium strain named as the KK1- strain (with 98% homology with Marinobacter litoralis) was isolated from enrichment consortium. Among the various variables screened using the Plackett-Burman experimental design, pH, temperature, salinity and NH4Cl were determined as the most significant factors and considered for the next stage of the biodegradation optimization process using the Taguchi experimental design. Theoretically, the optimum degradation conditions were determined to be: pH = 8, temperature = 35˚C, salinity = 30 ppt and NH4Cl = 1 g.L-1. The validity of the predicted optimized condition was tested by conducting experiments considering the predicted criteria. Biodegradation efficiency of 58.32±5.57% was achieved under the suggested conditions, which was significantly higher than that achieved by the primary conditions (35%). Indigenous bacteria from surface sediments of Qeshm Island were found to be able to degrade crude oil. Our results showed that a combination of the Plackett-Burman and the Taguchi experimental designs may be successfully used to find the optimal amounts of factors required for crude oil biodegradation.

In order to isolate and to identify naphthalene degrading bacteria from Nayband Bay sediments and to optimize biodegradation efficiency using the most effective isolated strain, surface sediment samples were collected from Nayband Bay mangrove forests. Obtained samples were then cultured on mineral salts medium (MSM) containing naphthalene as a sole carbon source. At the end of the enrichment, three bacterial strains in the consortium were isolated by spreading the 10-fold serially diluted consortium on nutrient agar plates. Naphthalene biodegradating efficiency of the isolated strains was monitored in two culture media: 1-MSM + naphthalene, 2-MSM + naphthalene + Tween-80. The ability of bacterial isolates to degrade naphthalene was studied by using gas chromatography. Among the isolated strains, SBU3 was found to be more efficient, degrading naphthalene in presence and absence of Tween-80, 60.45% and 39.30% respectively. This strain was identified by 16s rDNA gene sequence and results showed that it has 99% similarity to Marinobacter aquaeolei. The Optimum pH and C/N molar ratio for the biodegradation of naphthalene were studied in presence of 1% tween-80, results show that the pH 7.5 and C/N ratio of 100:10 were the optimum conditions and more than 85% of naphthalene removed within 7 days. Furthermore, the biodegradation kinetics of naphthalene corresponded with the first-order rate model.