Nowadays, there is increased interest in the biosynthesis of microbial melanin related to their numerous biological functions and applications in many fields, especially in medical fields, including immune-modulating, antimicrobial antibiotic, antiviral antivenin, anticancer, antitumor activity, and anti-biofilm activity. Pyomelanin is a hydrophobic macromolecule that is typically dark brown or black in color, formed by the oxidative polymerization of phenolic or indolic compounds. Pyomelanin is reported to be safe for consumption, thus providing a crucial strategy for biocontrol of biofilm. Furthermore, natural pyomelanin is known as a potent antioxidant, photoprotective, and free radical scavenging. Objective: This study focuses on the extraction and parametric optimization of melanin using Pseudomonas aeruginosa (P. aeruginosa) isolates. Materials and Methods: P. aeruginosa was isolated from various clinical sources, including urinary tract infections, burn patients, and wound infections. The isolate’s identification was done by biochemical, cultural, and VITEK-2 compact system. The isolates were subjected to pyomelanin production in nutrient agar supplemented with L-tyrosine, and the potential isolate was selected and employed for melanin production using nutrient broth supplemented with L-tyrosine. The pyomelanin-producing isolates were further identified through the PCR analysis technique. Different physical parameters were used for optimum pyomelanin yield. Results: The potential P. aeruginosa isolates were further identified using 16s rRNA. Pyomelanin production was better at 2.9 µg/mL at 100 rpm. The highest pyomelanin production was 3.07 µg/mL after 72 h incubation. The optimum pH at 7 was 3.12 µg/mL. The highest pyomelanin yield at 40°C was 3.03 µg/mL, while the maximum pyomelanin was produced using 2 g/L tyrosine at 2.99 µg/mL. UV-visible (UV-Vis) spectroscopy analysis for pyomelanin pigment was at 273.5 nm. The infrared spectrum exhibited a broad absorption band around 3280.82 cm−1 which corresponds to the presence of -OH and N-H groups. Conclusion: This study provides knowledge on factors affecting pyomelanin production using bacteria in broth media supplemented with L-tyrosine.
The current study aimed to use some bacterial isolates from the local soil of Baghdad city by study the effects of temperature, pH and incubation period on the growth rates of isolated bacteria and choose the optimal conditions for their diversity and for understanding bacterial growth and their requirements for survival and proliferation. This information can be applied to obtain their high growth rate for use in various fields such as agriculture, medicine and environmental sciences in the future. And it used to assess the degree of variation in across bacteria species in pH, temperature and incubation period. A number of local bacterial isolates as
Magnetic nanoparticles (MNPs) of iron oxide (Fe3O4) represent the most promising materials in many applications. MNPs have been synthesized by co-precipitation of ferric and ferrous ions in alkaline solution. Two methods of synthesis were conducted with different parameters, such as temperature (25 and 80 ̊C), adding a base to the reactants and the opposite process, and using nitrogen as an inert gas. The product of the first method (MNPs-1) and the second method (MNPs-2) were characterized by x-ray diffractometer (XRD), Zeta Potential, atomic force microscope (AFM) and scanning electron microscope (SEM). AFM results showed convergent particle size of (MNPs-1) and (MNPs-2) with (86.01) and (74.14)
... Show MoreThis study aims at detecting the differences in genotyping of coding region fusA gene in clinical isolates of Acinetobacter baumannii from Baghdad, Iraq. Collected two hundred clinical samples (50 samples from urine, 50 samples from wound, 50 samples from sputum and 50 samples from otitis infections). Laboratory diagnosis for bacterial isolates carried out by some biochemical tests and confirmed by using VITEK- 2 compact system. The results appeared that twenty isolates of Acinetobacter baumannii in all these samples. Genotyping study was performed of coding region fusA gene of the extracted genome of all bacterial isolates and used specific primers in achieved amplification process of this target gene. DNA sequencing of this gene and alig
... Show MoreThe effect of 532nm Diode Pumped Solid State (DPSS) laser at power density of 5.234 W/cm2 on the growth of Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus was evaluated. These bacteria were isolated from samples taken from burn and infected wound areas of 55 patients admitted to the burn-wound unit in Al-Kindy teaching hospital in Baghdad during the period from October 2012 to March 2013. Each isolate was identified using microscopic, cultural and biochemical methods. A standard bacterial suspension was prepared for each isolate. Serial dilutions were then prepared and a dilution of 10-5 was selected. Irradiation experiments included four groups: (L-P-) bacterial suspension in saline solution, (L-P+) bacteria
... Show MoreTwenty isolates of Serratia marcescens were isolated from inflammation of the urinary tract (UTI)., These isolates were found to produce hemolysin as indicated by blood agar plates in which the hemolysis of red blood cell indicate a positive result. Isolates were selected according to their hemolysis activity by measuring absorbance of hemoglobin at 405 nm that released from red blood cell. Hemolysin was completely purified using 50-75% saturation of ammonium sulphate followed by ion exchange chromatography with DEAE-cellulose then gel filtration chromatography by sepharose 4B. Accordingly molecular weight for the purified toxin was estimated as 45 KD.
Abstract
Friction stir welding is a relatively new joining process, which involves the joining of metals without fusion or filler materials. In this study, the effect of welding parameters on the mechanical properties of aluminum alloys AA2024-T351 joints produced by FSW was investigated.
Different ranges of welding parameters, as input factors, such as welding speed (6 - 34 mm/min) and rotational speed (725 - 1235 rpm) were used to obtain their influences on the main responses, in terms of elongation, tensile strength, and maximum bending force. Experimental measurements of main responses were taken and analyzed using DESIGN EXPERT 8 experimental design software which was used to develop t
... Show MoreThe hydrolysis of urea by the enzyme urease is significant for increasing the irroles in human pathogenicity, biocementation, soil fertilizer, and subsequently in soil improvement. This study devoted to the isolation of urease from urea-rich soil samples collected from seven different locations. Isolation of the various bacterial species was conducted using nutrient agar. The identity of isolated urease was based on morphological characteristics and standard microbiological and biochemical procedures. The urease producing strains of bacteria were obtained using the urease hydrolysis test. The bacterial isolates produced from soil samples collected from different environments and treat
The aim of this work is to detect the best operating conditions that effect on the removal of Cu2+, Zn2+, and Ni2+ ions from aqueous solution using date pits in the batch adsorption experiments. The results have shown that the Al-zahdi Iraqi date pits demonstrated more efficient at certain values of operating conditions of adsorbent doses of 0.12 g/ml of aqueous solution, adsorption time 72 h, pH solution 5.5 ±0.2, shaking speed 300 rpm, and smallest adsorbent particle size needed for removal of metals. At the same time the particle size of date pits has a little effect on the adsorption at low initial concentration of heavy metals. The adsorption of metals increases with increas
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