Objective: The present work was undertaken to investigate the impact of sub inhibitory concentration of gentamicin on hla gene expression in methicillin resistant Staphylococcus aureus isolates. Methods: The bacterial isolates used in this study represent 33 MRSA strains, previously isolated form patients visiting several hospitals in Baghdad. Gentamicin, vancomycin, and oxacillin MIC were determined using broth dilution method. Microtiter plate method was adopted to investigate the biofilm forming capacity. Alpha hemolysin was detected by culturing MRSA isolates on rabbit blood agar. Furthermore, hla gene was detected in MRSA isolates using conventional PCR technique; while, qRT-PCR method was performed to assay the hla expression in planktonic and biofilm cells in presence and absence of gentamicin. Results: the present results demonstrated that 12 (36.36%) isolates were gentamicin-resistant; whereas, all isolates were resistant to oxacillin and sensitive to vancomycin. Out of 33 MRSA, 3, 23, and 7 isolates formed a weak, moderate, and strong biofilm, respectively. Phenotypically, 30 isolates produced alpha hemolysin on rabbit blood agar plates; nevertheless, hla gene was located in 29 isolates. Of considerable interest, the addition of gentamicin significantly (P < 0.05) reduced the hemolysis activity; while, insignificant fold change (less than two) of hla gene was observed in all tested isolates in the presence of sub MIC of gentamicin (16 µg/ml). Conclusion: gentamicin upregulated the hla gene expression in biofilm cells; hitherto, this increment was isolate specific.
Food comes after air and water in terms of importance in the survival of human beings, In addition, it is the support and strength of health and support, if lost or destroyed man would die or get sick and become a heavy burden on himself and his society. Food, like other sources of life, is subject to various risks and corruption comes from countless sources. Among these dangers is the result of spontaneousness, lack of knowledge or compulsion due to the interaction of variables beyond the will of the producer and the consumer, such as pollution of water, air and environment and their reflection on food consumed by people. However, we can’t deny that some reasons of corruption are intentional and resulting from a planning in advance in
... Show MoreThe scarcity of irrigation water requires procedures of specific. One of these procedures is the implementation of the rationing system (a period of the irrigation followed by a period of the dry). This system can have an impact on the properties of irrigation channels. Therefore, the study of rationing system for irrigation channels is important in both water resources and civil engineering, especially if they are constructed with gypseous soil. In order to assess the rationing system on gypseous canals stabilized with a specific ratio of cement, practical experiments were conducted to detect the effect of wetting and drying cycles on the physical and hydraulic behavior of this soil and calculation of some properties of soil such a
... Show MoreThe electronic structure of zinc blend indium gallium phosphide In0.5Ga0.5P nanocrystals which have dimension (2-2.8 nm) is investigated using the density functional theory coupled with large unit cell (LUC) for the different size core (8 ,16,54,64) atoms respectively. The investigated properties include total energy, energy gap, conduction band, valence band, cohesive energy, ionicity and density of state etc. as a function of core size and lattice constant. Results show the shape effect of increasing the core size and lattice constant on these electronic properties
The general assumption of linear variation of earth pressures with depth on retaining structures is still controversial; investigations are yet required to determine those distributions of the passive earth pressure (PEP) accurately and deduce the corresponding centroid location. In particular, for rigid retaining walls, the calculation of PEP is strongly dependent on the type of wall movement. This paper presents a numerical analysis for studying the influence of wall movement on the PEP distribution on a rigid retaining wall and the passive earth thrust location. The numerical predictions are remarkably similar to existing experimental works as recorded on scaled test models and ful
In this study, the effect of the annealing temperature on the material properties and the structural properties of cuprous oxide was studied in order to investigate how the annealing temperature affects the material properties, and the temperature varied between 200℃, 300℃, 400℃ and 500 ℃ and was unannealed. The physical properties of the cuprous oxide were measured by X-ray diffraction (XRD). The XRD patterns showed that the Cu2O nanoparticles were highly pure, crystalline, and nano-sized. From the XRD results, we found the pure cuprite (Cu2O) phase. The values of crystal size were discovered and calculated by the Halder-Wagner and Size-Strain Plot (SSP) methods, respectively. The crystallite size increased
... Show Morepriorities of materials research due to their promising properties, especially in the field of thermoelectricity. The efficiency or performance of thermoelectric devices is expressed in terms of the thermoelectric figure-of-merit (ZT) – a standard indicator of a material’s thermoelectric properties for use in cooling systems. The evaluation of ZT is principally determined by the thermoelectric characteristics of the nanomaterials. In this paper, a set of investigative computations was performed to study the thermoelectric properties of monolayer TMDCs according to the semiclassical treatment of the Boltzmann transport equation. It was confirmed that the thermoelectric properties of 2D materials can be greatly improved compared with thei
... Show MoreThis study conduct in Al-Muthanna governorate to assess five concentrations of