No abstract

No abstract

In the past few decades, nanoparticles have emerged as a field in biomedical research. Four isolated Aspergillus species were tested for extracellular synthesis of silver nanoparticles using their cell free filtrate (CFF). Silver nanoparticles of the most potent producer, Aspergillus terreus, were further characterized. Transmission electron microscope (TEM) and atomic force microscope (AFM) revealed their spherical shape, homog eneity and size range between 20 and 140 nm. X-ray diffraction (XRD) showed the crystalline nature of the biogenic silver nanoparticles. Fourier transform infra-red (FTIR) spectroscopic analysis indicated that the coordination behaviors between amino groups of the secreted fungal proteins and other functional groups present in the CFF may be liable for the reduction of silver ions to form stabilized protein-capped silver nanoparticles. They were stable in aqueous solution for four months of storage at room temperature under dark conditions. The biogenic silver nanoparticles showed remarkable antifungal activity against the human pathogenic fungus A. fumigatus. The spore cell wall, plasma membrane and the inner constituents were damaged as shown by TEM. Furthermore, comet assay proved high breakage of DNA.

P ROPOLIS was responsible for in vitro growth suppression of some tested phytopathogenic fungi. Four tested species were partially inhibited by using propanolic or ethanolic extract associated with promising growth reduction of Fusarium oxysporum in a percent of growth recorded 38.2% or 58.9% during propanolic or ethanolic application, respectively, while Helminthosporium sp. and Cladosporium sp. showed unexpected activation of growth during propanolic or ethanolic extract applications. The antimicrobial products identified during GC-MS analysis of the propolis propanolic extract were Pyrazole, Quinic acid, D-lactic acid, Pentanoic acid, Erythritol and sulfonamide derivatives. The SDS gel electrophoresis of soluble proteins of Fusarium oxysporum treated with propanolic or ethanolic propolis extracts showed a specific protein band at 26.002kDa with the untreated pathogen, and several characterized bands at 21.160, 26.012, 28.666, 38.44, 102kDa related to propolis propanolic extract (2) and finally a two markedly visible bands at 18.871, 33.083kDa with propolis ethanolic extract (3). The decrease in enzyme activity of cellulase and pectinase of Fusarium oxysporum was recorded under treatment with either propanolic or ethanolic extracts. There was suppression in the degree of infectivity such as the number of rotted seeds, wilting, brown discoloration of Phaseolus seedlings presoaked in either of the two propolis extracts compared to infected plants with more reduction individually in case of propanolic extract over that of ethanolic one.

Sodium dodecyl sulfate-polyacrlyamide gel electrophoresis (SDS-PAGE) was used to assess the purity and molecular weight of the previously purified alkaline keratinase enzyme of Scopulariopsis brevicaulis. The enzyme was homogenous, as seen by a single band of protein, and had an apparent molecular weight of 28.5 kDa. Amino acid profile of the purified keratinase revealed that it was composed of 14 different amino acids with high proportions of glutamic acid (20.86%), alanine (14.52%), glycine (14.21%), leucine (8.59%) and serine (7.81%). The enzyme contained moderate amounts of valine (6.01%), threonine (5.58%) and phenyl alanine (5.22%). The purified enzyme of S. brevicaulis exerted a potent keratinolytic activity and was capable to hydrolyze different keratinaceous materials with highest activity on chicken feathers followed by human nails and human hair.