Abd El-Raheem R. El-Shanshoury

Biologically active polymers: synthesis and antimicrobial activity of modified glycidyl methacrylate polymers having a quaternary ammonium and phosphonium groups

Polymers with antibacterial activity have been synthesized by chemical modification of poly(glycidyl methacrylate). The glycidyl methacrylate was polymerized by the free radical polymerization technique. The poly(glycidyl methacrylate) was hydrolyzed and was chloroacetylated using chloroacetyl chloride. The chloroacetylated product was modified to yield polymers with either quaternary ammonium or phosphonium salts. The antimicrobial activity of the modified glycidyl methacrylate polymers has been examined against a variety of test microorganisms by the cut plug and the viable cell counting methods using shake flask of ten times diluted nutrient broth medium. All three polymers obtained were inhibitory to the growth of Gram negative bacteria (Escherichia coli, Pseudomones aeruginosa, Shigella sp. and Salmonella typhae) and Gram positive bacteria (Bacillus subtilis and B. cereus) as well as the fungus (Trichophytun rubrum). It was found that the growth inhibitory effect varied according to the structure of the polymer and the composition of the active group and increased with increasing the concentration of the polymer. The tested polymers showed more antimicrobial activity against Gram negative bacteria and the fungus, whereas were less active against Gram positive bacteria.

Isolation and Molecular Characterization of Heavy Metal-Resistant Alcaligenes faecalis from Sewage Wastewater and Synthesis of Silver Nanoparticles

Environmental pollution with toxic heavy metals is increasing throughout the world alongside industrial development. Microorganisms and microbial products can be highly efficient bioaccumulators of soluble and particulate forms of metals, especially dilute external solutions. Microbe related technologies (Biotechnology) may provide an alternative or additive conventional method for metal removal or metal recovery. This study dealt with isolation, identification and characterization of heavy metal-resistant (Pb2+, Cd2+, Al3+, Cu2+, Ag2+ and Sn2+) bacteria from sewage wastewater at Taif Province, Saudi Arabia. Nine bacterial isolates were selected by using an enrichment isolation procedure based on high level of heavy metal resistance. All the isolates showed high resistance to heavy metals with Minimum Inhibitor Concentration (MIC) ranging from 800 μg/ml to 1400 μg/ml. All nine resistant isolates showed multiple tolerances to heavy metals. On the basis of morphological, biochemical and 16S rRNA characterization, the most potent isolates (Cd1-1, Ag1-1, Ag1-3 and Sn1-1) were identified as Alcaligenes faecalis. Scanning electron microscope analysis showed that the morphology of Alcaligenes faecalis Ag1-1 was unchanged after growth in medium without and with addition of Ag2+ indicative Ag2+ is not toxic to the isolate under the conditions tested. The ability of Alcaligenes faecalis Ag1-1 to synthesize sliver nanoparticles was examined. The heavy metal-resistant bacteria obtained could be useful for the bioremediation of heavy metal-contaminated environment.

Diagnostic performances of hepatitis C virus-NS4 antigen in patients with different liver pathologies.

BACKGROUND AND AIMS Hepatitis C virus (HCV) has emerged as the major pathogen of liver disease worldwide. The aim of this study was to quantitate and evaluate the performance of HCV-NS4 antigen as an alternative approach for confirmation of viremia. METHODS Detection of HCV-NS4 was assessed in 883 patients with chronic hepatitis C. Areas under the ROC curves (AUC) were used to assess and compare diagnostic accuracy of ELISA for HCV-NS4 with quantitative HCV-RNA as a gold standard. RESULTS HCV-NS4 was identified at 27 kDa using Western blot. AUC for HCV-NS4 detection was 0.95 for all patients with different liver pathologies: 0.93 for liver fibrosis (LF), 0.95 for liver cirrhosis (LC) and 0.98 for hepatocellular carcinoma (HCC). The mean ± SD (μg/mL) of HCV-NS4 in LF was 94.2 ± 55.6; in LC was 99.3 ± 64.8 and in HCC was 124.9 ± 70.3. CONCLUSIONS HCV-NS4 antigen detection using ELISA is a reliable test in the confirmation of HCV infection.

Synthesis of lead nanoparticles by Enterobacter sp. and avirulent Bacillus anthracis PS2010

The bacteria Enterobacter sp. and Bacillus anthracis (avirulent strain) were isolated from a lathe workshop and industrial waste water, respectively. The ability of both isolates to synthesize lead nanoparticles was studied. The relationship between the amount of polysaccharides secreted and metal deposited was demonstrated. The more polysaccharides secreted, the less metal deposition occurred. Examination of cells with X-ray diffraction (XRD), energy dispersive X-ray (EDX) and electron microscopy (EM) after lead treatments revealed changes in cell size and surface. The cell surface of Bacillus anthracis PS2010 decreased relative to cell volume. XRD and EDX indicated that cells of Enterobacter sp. were able to synthesize lead oxide (PbO) nanoparticles within the periplasmic space, while B. anthracis cells were found to be able to synthesize lead sulfide (PbS) nanoparticles extracellularly.

Isolation of Bdellovibrio sp. from Wastewater and Their Potential Application in Control of Salmonella paratyphi in Water

ABSTRACT The problem of the increasing resistance of bacteria to conventional antibiotics gives the bacteria Bdellovibrio a great utility as a potential alternative source of antibiotics. Therefore, the preliminary goal of the present study was isolation and identification of antibiotic-resistant bacteria used as prey organisms for isolated Bdellovibrio sp., by xylose lysine desoxycholate (XLD) agar from different types of water in the Taif area, Saudi Arabia, and also to investigate water quality. Four antibiotic-resistant isolates of Salmonella sp. which were susceptible to Bdellovibrio were identified by morphological, biochemical and 16S rRNA characterization as Salmonella paratyphi. Seventeen strains of Bdellovibrio sp. were isolated from sewage wastewater using isolated S. paratyphi as prey bacteria by a double-layer plate. Only one of them causing a large plaque after 48 h of incubation at 37°C was designated Bdellovibrio AOA12. The shape of Bdellovibrio was confirmed by morphological characterization and electron microscopy. Bdellovibrio could lyse four antibiotic-resistant Gram-negative bacterial strains of Salmonella paratyphi but could not lyse Gram-positive bacteria such as Staphylococcus aureus and Bacillus cereus. The kinetic lysis of the Bdellovibrio as predator to four isolates of antibiotic-resistant Salmonella paratyphi as prey organisms was demonstrated. The results suggest that it may be possible to utilize Bdellovibrio to control antibiotic-resistant S. paratyphi in water.

Exopolysaccharides Produced by Pseudomonas syringae Pathovars

Different pathovars belonging to Pseudomonas syringae were tested for the production of exopolysaccharides (EPS). In shake fiask cultures, maximum yield of EPS (1.8 g/l) and viscosity (4.1 mPas) were achieved by culturing the most promising bacterial strain of P. syringae pv. phaseolicola in gluconate mineral medium at 25°C for 3 days. In batch fermenter culture, yield and viscosity of the EPS increased 3.3-fold compared to shake fiask culture. The partially purified bacterial EPS obtained consisted mainly of alginate and showed better rheologicai characteristics than commercial preparations obtained from aigae. Specimens of EPS from different pathovars were filter sterilized and injected into young leaves of different plant species. In some combinations, persistent water-soaked spots were induced. EPS preparations from different P. syringae pathovars other than P. syringae pv. phaseolicola did not reveal host-specific characters.