3 research outputs found
Biochemical and molecular characterization of Haemophilus influenza isolated from Riyadh, Kingdom of Saudi Arabia
The objective of this study focused on the prevalence of Haemophilus influenza to confirm the colonies of H. influenza on the basis of their growth requirements and serotype distribution. This study prepared 80 isolates of H. influenze isolated from five different sources (eye, ear, sputum (SP), lower genital tract (TA), and nasopharyngeal (NPA)) with different ages for infants and elderly persons. The phenotypic characteristics, which included the biotype, serotype, antibiogram and β-lactamase production, were applied by using APINH and minimum inhibitory concentration (MIC). Also, the study focused on the identification of selected serotype using PFGE analysis. The discussion of this study differentiates the age groups occurrence in the isolates, alongside with non-typeable strain versus the typeable ones and their percentages in the sample of isolates. This clustering of most strains in on e PFGE pattern might be explained with the colonel population structure of the encapsulated H. influenza
Ecotoxicity of Ag-nanoparticles on two microalgae, Chlorella vulgaris and Dunaliella tertiolecta
Ecotoxicity of Ag-nanoparticles on two microalgae, Chlorella vulgaris and Dunaliella tertiolecta
The increasing application of nanotechnology highlights the need to clarify
and understand it. In this work, the subacute toxicity of Ag-NPs to the fresh
water microalga Chlorella vulgaris and marine microalga Dunaliella
tertiolecta were assessed. The effect of Ag-NPs was induced by exposing both
algae to increasing concentrations of Ag-NPs (0, 10, 50, 100 and 200 mg/L).
Cellular viability and reactive oxygen species (ROS) formation were
determined to evaluate the toxic effect of Ag-NPs on algal growth. Superoxide
dismutase (SOD), catalase (CAT) and peroxidase (POD) activities and lipid
peroxidation (MDA) levels in the algal cells varied with the concentration of
Ag-NPs suspensions and exposure times (up to 8 d). As a result, 100 and 200
mg/L Ag-NPs caused a statistically significant decrease in cell viability, as
well as SOD, CAT and POD activities, and a significant increase in ROS
formation and MDA levels in tissues (P <0.05), suggesting that the algal
cells exposed to these two concentrations of Ag-NPs suffered from oxidative
stress. The extent of depletion of antioxidant enzyme activities and the
elevation of MDA in Dunaliella tertiolecta was the greatest, indicating that
Dunaliella tertiolecta might be the most susceptible to Ag-NP exposure. These
results indicated a potential risk from Ag-NPs released into the aqueous
environment