Alternative therapy to manage otitis media caused by multidrug-resistant fungi.

During the last few decades, the increase in the incidence of multidrug-resistant (MDR) fungal infections has become an emerging threat to public health. Therefore, it is important to illuminate the usage of alternative therapy to treat MDR fungal infection. This study was carried out to elucidate the usage of plant extract and essential oil, either alone or with other antifungal drugs to treat otitis media caused by MDR fungi. Medicinal plant is a safe and cheap source when compared with chemical antifungal drugs. Twenty-one fungal isolates out of 104 ear swabs from patients suffering from otitis media were characterized using both phenotypic and genotypic methods. The antibiogram typing was used to determine the MDR isolates. The sensitivity of MDR fungal isolates was tested against several plant extracts and essential oils, either alone or with other antifungal drugs. Thyme oil and clove extracts proved to have synergistic effects suggesting their use in the treatment of fungal infections, especially otitis media caused by MDR fungi. The ultrastructure of MDR fungal isolates exhibited a complete destruction post exposure to the used materials when observed under the transmission microscope (TEM). Thyme oil and clove extract were found to be the most effective agents against MDR fungal isolates and they constitute a promising tool for the management of fungal infection causing the otitis media.

Characterization of Streptomyces isolates causing colour changes of mural paintings in ancient Egyptian tombs.

Paintings in ancient Egyptian tombs often suffer colour changes due to microbial growth and colonization. Streptomyces strains were isolated from mural paintings of Tell Basta and Tanis tombs (East of Nile Delta, Egypt) and were identified using biochemical and molecular methods. The16S rDNA sequences data indicated that isolated strains were closely related to S. coelicolor, S. albidofuscus, S. ambofaciens, S. canarius, S. parvullus, S. corchorusii, S. albidofuscus and S. nigrifaciens. It could be shown that Streptomyces strains are involved on a large scale in the colour changes of paintings and stone support by producing a wide range of metabolites such as acids (oxalic, citric and sulphuric acids), biopigments of melanin, carotenoids, and hydrogen sulphide.

Membrane-bound quinoprotein D-arabitol dehydrogenase of Gluconobacter suboxydans IFO 3257: a versatile enzyme for the oxidative fermentation of various ketoses.

Solubilization of membrane-bound quinoprotein D-arabitol dehydrogenase (ARDH) was done successfully with the membrane fraction of Gluconobacter suboxydans IFO 3257. In enzyme solubilization and subsequent enzyme purification steps, special care was taken to purify ARDH as active as it was in the native membrane, after many disappointing trials. Selection of the best detergent, keeping ARDH as the holoenzyme by the addition of PQQ and Ca2+, and of a buffer system involving acetate buffer supplemented with Ca2+, were essential to treat the highly hydrophobic and thus labile enzyme. Purification of the enzyme was done by two steps of column chromatography on DEAE-Toyopearl and CM-Toyopearl in the presence of detergent and Ca2+. ARDH was homogenous and showed a single sedimentation peak in analytical ultracentrifugation. ARDH was dissociated into two different subunits upon SDS-PAGE with molecular masses of 82 kDa (subunit I) and 14 kDa (subunit II), forming a heterodimeric structure. ARDH was proven to be a quinoprotein by detecting a liberated PQQ from SDS-treated ARDH in HPLC chromatography. More preliminarily, an EDTA-treated membrane fraction lost the enzyme activity and ARDH activity was restored to the original level by the addition of PQQ and Ca2+. The most predominant unique character of ARDH, the substrate specificity, was highly versatile and many kinds of substrates were oxidized irreversibly by ARDH, not only pentitols but also other polyhydroxy alcohols including D-sorbitol, D-mannitol, glycerol, meso-erythritol, and 2,3-butanediol. ARDH may have its primary function in the oxidative fermentation of ketose production by acetic acid bacteria. ARDH contained no heme component, unlike the type II or type III quinoprotein alcohol dehydrogenase (ADH) and did not react with primary alcohols.

Use of propolis and ultragriseofulvin to inhibit aflatoxigenic fungi.

Propolis ethanolic extract (PEE) at 3 and 4 g/L and ultragriseofulvin (UG) at 0.75 and 1 g/L reduced the percentage of conidia germination in two Aspergillus flavus isolates. PEE at 1-4 g/L decreased the mycelial dry mass of A. flavus isolates by 11-80%, and aflatoxin B1 production by 34-100%. UG concentrations of 0.25-1 g/L reduced the growth and aflatoxin B1 production of the isolates by 16-88 and 48-98%, respectively. Any increase in PEE and UG concentration was accompanied by a clear decrease in the per cent conidia germination, growth and aflatoxin B1 production. At equal concentration, UG was about 4-times more effective than PEE.