Khayria M. Abdel-Gawad

Antibacterial, antidermatophytic and antitoxigenic activities of onion (Allium cepa L.) oil

The inhibitory effect of onion oil against the growth of various isolates of bacteria representing Gram-positive (4 isolates) and Gram-negative (4 isolates) species were studied. Results show that onion oil was highly active against all Gram-positive bacteria tested and only one isolate (Klebsiella pneumoniae) of Gram-negative bacteria. The inhibitory effect of onion oil against nine different species of dermatophytic fungi were also studied. Onion oil (200 ppm) completely inhibited the growth of Microsporum canis, M. gypseum and Trichophyton simii while the growth of both, Chrysosporium queenslandicum and Trichophyton mentagrophytes was completely inhibited by 500 ppm of onion oil. The growth of four other species of dermatophytic fungi was gradually reduced by increasing the concentrations of onion oil. The inhibitory effect of onion oil was also tested against four toxigenic isolates of fungi. Onion oil at different concentrations (100, 200 and 500 ppm) tested gradually reduced fungal growth and aflatoxin production by Aspergillus flavus IMI 89,717 and A. parasiticus var. globosus IMI 120,920. Fungal growth and production of sterigmatocystin and rubratoxin A by A. versicolor IMI 16,139 and Penicillium rubrum IMI 136,127 were completely inhibited by the addition of 200 ppm onion oil.

Spatio-temporal, environmental factors, and host identity shape culturable-epibiotic fungi of seaweeds in the Red Sea, Egypt

The study of fungal species diversity from marine algae is in its infancy; as now no studies have been carried out on the distribution and diversity of fungi on the surfaces of marine macroalgae where all fungal–algal interactions tend to begin. The aim of this study was to isolate and describe the culturable part of mycobiota associated with the surface of benthic marine macroalgae (epiphytic or epibiotic fungi). This is an important step in understanding their abundance, diversity and factors influencing their variability and composition. The fungal community was dominated by Ascomycetes (89%) with Eurotiales as the most abundant fungal order followed by Capnodiales, Pleosporales, and Hypocreales, while Zygomycetes was less frequent. The nature of occurrence of fungal genera on different macroalgal hosts suggests that a mix of generalists’ framework applies to fungal epiphytes of seaweeds, but the abundance of fungal taxa varied among ecological functional groups of algae, as well as macroalgal taxonomic groups, which imply host filtering. The fungal assemblages were also characterized by temporal variation with variation in temperature, pH, and salinity as the most important abiotic factors. The structure of fungal assemblages showed high beta diversity and low similarity between hosts.

Ecological and physiological studies on fungi associated with human hair.

Thirty-seven species attributed to 19 genera of keratinophilie fungi were recovered from 100 human hair samples collected from the Assiut governorate. The generaAspergillus followed byPenicillium andChrysosporium were frequently isolated from 65, 43 and 30% of the samples respectively. Fifteen species and 13 genera of thermophilic and thermotolerant fungi (recovered at 45°C) were identified. The thermotolerantAspergillus fumigatus was frequently encountered and emerged from 82% of the samples. Thirteen isolates of keratinophilie and 20 isolates of thermophilic fungi were tested for lipolytic and proteolytic activities. All the keratinophilic fungi showed lipolytic and proteolytic activities while 100 and 85% of the thermophilie fungi showed lipolytic and proteolytic activities. Using the paper-disc plate method, 12 types of shampoos and oils were tested for their antifungal activities on 42 strains of keratinophilic and thermophilic or thermotolerant fungi. Three out of four types of shampoo proved to be highly effective against all the test fungi. The authors are deeply indebted to Prof. Dr. I.A. El-Kady (Botany Department, Faculty of Science, Assiut University) for valuable help.

Optimization of alginate alkaline extraction technology from Sargassum latifolium and its potential antioxidant and emulsifying properties

Alginate was recovered from Sargassum latifolium biomass using different conditions of alkali treatment. Box-Behnken experimental design was evaluated to study the influence of alkali:alga ratio, temperature and time on alginate yield, and its molecular weight (MW) and mannuronic/guluronic acid ratio (M/G). The second-order polynomial equations were analyzed by appropriate statistical methods. Extraction temperature and time were the most important factors during alginate alkaline extraction. MW and M/G ratio played an important role in controlling the reducing power of alginate. Increasing pH of the alginate solutions enhanced its reducing capacity, while thermal treatment showed a negative effect. Additionally, alginate exhibited good emulsion stabilizing capacities with diverse hydrophobic compounds. Emulsifying activity was less sensitive to temperature, ionic strength and more stable at acidic pH.

Spatio temporal and environmental factors influencing macroalgal β diversity in the Red Sea, Egypt

Abstract β Diversity is an ecological concept used to describe the turnover of species across a wide range of spatial and temporal scales, but such knowledge is lacking for macroalgal assemblages of the Red Sea. β Diversity patterns for Red Sea macroalgae were evaluated from different sites (Hurghada, Safaga, and Al-Quseir) and seasons across different environmental disturbances. β Diversity was studied by partitioning the total number of species (γ diversity) into additive components. Geographical heterogeneity was more important than seasonal heterogeneity in structuring macroalgae both at species and functional group levels. Species replacement as a component of β diversity produced dissimilarity in species composition and taxonomic structure. Replacement of species between sites was responsible for the presence of new functional groups of macroalgae. High β diversity and taxonomic similarity values were characteristic of the macroalgae of the Red Sea. The occurrence of small macroalgal thalli that have short life cycles induced high species replacement and subsequently high β diversity, with spatial heterogeneity and environmental gradient as drivers of β diversity. Anthropogenic disturbance at the Safaga site was suggested to induce variation of macroalgal assemblages and functional groups. Excluding rare species from the data set did not change the high values of b diversity.

In Vitro Comparative Evaluation of Antioxidant Activity of Hydrophobic and Hydrophilic Extracts from Algicolous Fungi

ABSTRACT The screening of potential antioxidant activities of hydrophobic (ethyl acetate) and hydrophilic (polysaccharide) extracts from both mycelia and fermentation media of eleven algicolous fungi was performed using three antioxidant assays. Algicolous fungi were able to ferment low-cost nutrients composed of potato infusion, glucose, and natural seawater and produce hydrophobic and hydrophilic metabolites with antioxidant properties. Significant differences were observed in antioxidant activities of extracts from the various species evaluated using total antioxidant activity (TAA), hydroxyl radical scavenging activity (HRSA), and ferric reducing antioxidant power (FRAP), as well as their total sugar contents (TSC) of hydrophilic extracts and total phenolic contents (TPC) of hydrophobic extracts. TSC of endopolysaccharides was higher than exopolysaccharides and showed a significant correlation with both TAA and FRAP. Most of mycelial extracts were richer in phenolics than fermentation media, and TPC of hydrophobic extracts was significantly correlated with their FRAP. Mycelial extracts for most of algicolous fungi showed higher antioxidant activities than fermentation media. Both hydrophobic and hydrophilic extracts of algicolous fungi showed good antioxidant properties, especially as hydrogen-donating antioxidants, which could be considered for future applications in medicine, food production, or cosmetic industry.

Upgrading the antioxidant properties of fucoidan and alginate from Cystoseira trinodis by fungal fermentation or enzymatic pretreatment of the seaweed biomass

The seaweed Cystoseira trinodis was fermented by different fungi prior to extraction of fucoidan and alginate to enhance their antioxidative potential. All the investigated fungi were able to produce fucoidanase (1.05-3.41 U/ml) and alginate lyase (7.27-18.59 U/mL). Different fungal species induced a reduction in the molecular weight (MW) of fucoidan and alginate in comparison to the unfermented control. The MW of fucoidan reduced by 41-81.5%, while the MW of alginate was reduced by 28-75%, depending on the fungal species. Significant increases in the fucose and sulphate contents of fucoidan and mannuronic/guluronic acid ratio of alginate were induced by fungal fermentation. Fungal pretreatment enhanced the ferric reducing antioxidant power, total antioxidant capacity and hydroxyl radical scavenging activity of both fucoidan and alginate. Additionally, enzymatic pretreatment of the macroalgal biomass assisted in the recovery of fucoidan and alginate with low molecular weight and enhanced antioxidative potential.

Mycota on Some Agarics Found in Assiut

This study is aimed to investigate about the fungal flora of some agaric fungi in Assiut, Egypt wild mushroom were collected during cold weather from November to February in the years 1995 and 1996 respectively. Twenty three species and one variety belong to 12 genera in 7 families of the order Agaricales from Assuit were identified. The common genera were Agaricus, Macrolepiota and Corprinus. From the preceeding genera, four species from each genus were collected. Agaricus bitorquis, A. campestris, A. hortensis, A. perraus, Macrolepioya, M. rhacodes, M. rhacodes var. Hortensis, Macrolepiota sp., Coprinus atramentarius, C. comatus, C. picaceus and C. nosoustii.