Abbas Yousefi Rad

Molecular imprinting based composite cryogel membranes for purification of anti-hepatitis B surface antibody by fast protein liquid chromatography.

In the present study, we have focused our attention to prepare molecular imprinted composite cryogel membranes for purification of hepatitis B surface antibody (anti-HBs) by fast protein liquid chromatography. Before the preparation of the molecular imprinted composite cryogel membranes (MI-CMs) by free radical polymerization at sub-zero temperature, we have synthesized and characterized the anti-HBs imprinted particles. Then, the cryogel membranes (CMs) were characterized by swelling test, scanning electron microscopy and Fourier transform infrared spectroscopy. Prior to chromatographic purification studies, the effective parameters on the anti-HBs adsorption process were evaluated by investigating the dependency of the adsorption capacity on flow-rate, anti-HBs concentration, contact time and ionic strength. The maximum anti-HBs adsorption capacity was calculated as 701.4 mIU/g CM. The selectivity of the MI-CMs was shown by competitive adsorption of anti-HBs, total anti-hepatitis A antibody (anti-HAV) and total immunoglobulin E (IgE) adsorption studies. The MI-CMs have relative selectivity coefficients as 5.45 for anti-HBs/total anti-HAV and 9.05 for anti-HBs/total IgE, respectively. The phosphate buffer solution (pH 7.4) containing 1.0M NaCl was used for elution, almost completely, of adsorbed anti-HBs molecules. The MI-CMs could be used many times without any significant decrease in the adsorption capacity. The chromatographic purification performances of the MI-CMs were also investigated. The chromatographic parameters such as capacity and separation factors, the theoretical plate number and resolution of the MI-CMs were calculated as 5.48, 6.02, 1153.9, and 1.72 for anti-HBs molecules, respectively. As a conclusion, we can say that the MI-CMs could be used for specific purification of anti-HBs from anti-HBs positive human plasma.

Seasonal and Spatial Variations of Bioaerosols in Indoor Urban Environments, Ankara, Turkey

Seasonal and spatial variations of both levels and characteristics of airborne bacteria and fungi in various types of non-complaint indoor environments and their outdoors were investigated. Bioaerosol samples were collected by the single-stage Andersen sampler during the winter and summer seasons in Ankara, Turkey. Indoor and outdoor temperature, relative humidity (RH) and CO2 concentrations were also monitored online during the sampling. Bacteria levels in apartments were found to be considerably elevated when people were present. Significant relationships between bioaerosol levels and RH and CO2 concentrations (p<0.05) were found. Bacteria levels exhibited a seasonal variation, while fungi levels did not, probably due to lower fungi concentrations occurrence as a result of lower RH values (median: 30%). Measured low levels of fungi in this study may be due to geographical conditions, climatic factors, and other environmental conditions. The indoor to outdoor (I/O) ratio for bacteria levels were found to be significantly higher than 1.0, while indoor and outdoor fungi levels were similar. Winter to summer (W/S) ratios in the sampling site groups varied on a large scale for both culturable fungi concentrations (0.24–19.59) and total bacteria count (0.16–6.59). The most prominent bacteria were Micrococcus spp., Staphylococcus spp. and Bacillus spp., while the most predominant fungi were Penicillium spp., Aspergillus spp. and Cladosporium spp.

Specific adsorption of the autoantibodies from rheumatoid arthritis patient plasma using histidine-containing affinity beads

Rheumatoid arthritis is characterized by chronic polyarthritis and destruction of multiple joints. In this study, poly(hydroxyethyl methacrylate-N-methacryloyl-(L-histidine)-methylester) (PHEMAH) beads were used in the removal of pathogenic antibodies from rheumatoid arthritis patient plasma in a packed bed column. PHEMAH beads, in the size range of 80–120 μm, were produced by suspension polymerization. The beads were contacted with blood in an in vitro system. Loss of blood cells and clotting times were followed. PHEMAH beads were characterized by scanning electron microscopy. We found that PHEMAH beads had a spherical shape and porous structure. Loss of cells in the blood contacting with PHEMAH beads was negligible. IgM-antibody adsorption capacity decreased significantly with the increase of the plasma flow-rate. With increasing IgM-antibody concentration, the amount of IgM-antibody adsorbed per unit mass increased and then reached saturation. Maximum IgM-antibody adsorption amount was 69.2 mg/g. IgM-antibody molecules could be repeatedly adsorbed and desorbed without noticeable loss in the IgM-antibody adsorption amount.

Quorum sensing molecules production by nosocomial and soil isolates Acinetobacter baumannii

Acinetobacter species remain alive in hospitals on various surfaces, both dry and moist, forming an important source of hospital infections. These bacteria are naturally resistant to many antibiotic classes. Although the role of the quorum sensing system in regulating the virulence factors of Acinetobacter species has not been fully elucidated, it has been reported that they play a role in bacterial biofilm formation. The biofilm formation helps them to survive under unfavorable growth conditions and antimicrobial treatments. It is based on the accumulation of bacterial communication signal molecules in the area. In this study, we compared the bacterial signal molecules of 50 nosocomial Acinetobacter baumannii strain and 20 A. baumannii strain isolated from soil. The signal molecules were detected by the biosensor bacteria (Chromobacterium violaceum 026, Agrobacterium tumefaciens A136, and Agrobacterium tumefaciens NTL1) and their separation was determined by thin-layer chromatography. As a result, it has been found that soil-borne isolates can produce 3-oxo-C8-AHL and C8-AHL, whereas nosocomial-derived isolates can produce long-chain signals such as C10-AHL, C12-AHL, C14-AHL and C16-AHL. According to these results, it is possible to understand that these signal molecules are found in the infection caused by A. baumannii. The inhibition of this signaling molecules in a communication could use to prevent multiple antibiotic resistance of these bacteria.

Anti-Quorum Sensing Potential of Antioxidant Quercetin and Resveratrol

Quorum sensing system plays an active role in the regulation of pathogenicity of many microorganisms. Inhibition of pathogenicity or virulence factors will increase the success of treatment by preventing the development of antibiotic resistance. In this study, anti-quorum sensing activities of quercetin and resveratrol compounds, which have antioxidant property without damaging to host, have been determined via using biosensor bacteria: Chromobacterium violaceum ATCC 12472 and Chromobacterium violaceum CV026. As quorum sensing inhibitors, quercetin and resveratrols cutting off the bacterial communication will prevent the treatment failures caused by the development of bacterial resistance. The development of layered drugs with antioxidant compounds such as quercetin and resveratrol will pave the way for new horizons for new therapeutic strategies.