Endophytic fungi from the medicinal herb Euphorbia geniculata as a potential source for bioactive metabolites.

Many researchers proved that plant endophytes manage successful issues to synthesize active chemicals within plant cells. These bioactive compounds might support a range of plant defense mechanism against many pathogenic microorganisms. In this study, a total of 22 isolates representing 21 fungal species belonging to 15 fungal genera in addition to one variety were isolated and identified for the first time from Euphorbia geniculate plants. The genus Aspergillus was the most common fungus isolated from the studied plant. The fungus Isaria feline was recorded in both leaves and stem, while Aspergillus flavus, A. ochraceus, A. terreus var. terreus, Emercilla nidulans var. acristata, Macrophomina phaseolina colonized both stem and root. The isolated fungi showed antagonistic activities against six strains of plant pathogenic fungi viz., Eupenicillium brefeldianum, Penicillium echinulatum, Alternaria phragmospora, Fusarium oxysporum, Fusarium verticilloid, and Alternaria alternata in dual culture assay. The highest antagonistic activity fungal species (Aspergillus flavus, A. fumigatus, and Fusarium lateritium) and the lowest (Cladosprium herbarum, F. culomrum, and Sporotrichum thermophile) showed twining in their secondary metabolites especially terpens and alkaloids with that of their host E. geniculata. Three concentrations of (0.5, 1.0, and 2.0 mg/ml) of these secondary metabolites extracted by ethyl acetate and n-butanol from the above six endophytic fungal species were tested against three pathogenic fungi isolated from infected tomato plant (E. brefeldianum-EBT-1, P. echinulatum-PET-2, and A. phragmospora-APT-3), whereas these pathogens showed promising sensitivity to these fungal secondary metabolites. In conclusion, this is the first report on the isolation of endophytic fungi from E. geniculata and evaluation of their antifungal activity.

Bacillus methylotrophicus ASWU-C2, a strain inhabiting hot desert soil, a new source for antibacterial bacillopyrone, pyrophen, and cyclopeptides.

A strain of Bacillus methylotrophicus was isolated from a soil sample collected in Aswan eastern desert, which is known for its extremely arid climate. After fermentation of the strain in liquid culture and subsequent extraction, a bioassay-guided isolation procedure yielded five compounds: 2-benzyl-4H-pyran-4-one, named bacillopyrone (1), pyrophen (2), macrolactin A (3) and the cyclopeptides malformin A1 (4), and bacillopeptin A (5). The structures were determined by interpretation of nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry (HR-MS) data. This is the first report on the isolation of compounds 1 and 2 from Bacillus species; compound 1 was reported previously as synthetic product. Bacillopyrone (1) exhibited moderate activity against the Gram-negative Chromobacterium violaceum with minimum inhibitory concentration 266.6 µg/mL, while macrolactin A (3) and malformin A1 (4) inhibited Staphylococcus aureus (minimum inhibitory concentrations 13.3 and 133.3 µg/mL, respectively).

alpha-Tomatine, the major saponin in tomato, induces programmed cell death mediated by reactive oxygen species in the fungal pathogen Fusarium oxysporum.

The tomato saponin alpha-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in alpha-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. alpha-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F(0)F(1)-ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to alpha-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that alpha-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca(2+) elevation and ROS burst in F. oxysporum cells.

Biodegradation of poly (ε-caprolactone) (PCL) film and foam plastic by Pseudozyma japonica sp. nov., a novel cutinolytic ustilaginomycetous yeast species.

Aliphatic polyesters poly (ε-caprolactone) (PCL) and foam plastic have been shown to be biodegradable by microorganisms, which possess cutinolytic enzymes. Pseudozyma japonica-Y7-09, showed both high growth and enzyme activity on Yeast malt (YM) medium fed with PCL film than on YM medium. The hydrolytic enzyme activity of the culture on p-nitrophenyl butyrate indicated the occurrence of cutinase enzyme. This activity was confirmed by the degradation of PCL film which reached to the maximum (93.33 %) at 15 days and the degradation of foam plastic which reached 43.2 % at 30 days. These results suggest that the extracellular cutinase enzyme of Pseudozyma japonica-Y7-09 may be useful for the biological degradation of plastic wastes.

Antifungal effects of Ficus sycomorus and Pergularia tomentosa aqueous extracts on some organs in Bufo regularis treated with Aspergillus niger.

The antifungal efficacy of Ficus sycomorus and Pergularia tomentosa plant extracts on Bufo regularis experimentally infected with Aspergillus niger was studied. After an oral administration of the pathogen for 15 days, the blood, kidney and liver were examined. Treatment with A. niger produced a reduction in red blood count cells and hemoglobin content. Also, both livers and kidneys revealed marked destruction and degenerative changes. These changes included congestion of blood vessels, leukocytic infiltration, and cytoplasmic vacuolization of the hepatocytes. As well as complete destruction of the cellular boundaries of the tubular epithelia, inflammatory leukocytes between the intertubular spaces, destruction and necrosis in renal tubule cells and the swollen glomeruli with wide glomerular spaces were seen. Pretreatment with F. sycomorus and P. tomentosa plant extracts 1h prior the administration of A. niger for two weeks improved blood parameters and protected against hepatic and renal damage as observed from histological examination and reduced spore numbers in culture media on these organs.

Mycoflora associated with Hyoscyamus muticus growing under an extremely arid desert environment (Aswan region, Egypt).

Hyoscyamus muticus L. (Egyptian henbane) is one of the desert medicinal plants of family Solanaceae. The plant produces pharmaceutically important compounds (tropane alkaloids) as secondary metabolites. In the present study, we describe mycoflora of H. muticus grown in four different locations in Egyptian southern desert (Aswan region): Aswan university campus, Wadi Allaqi down stream part, Aswan airport road, and Sahari city. Eighty-one species and two varieties belonging to 31 genera were isolated from soils surrounding H. muticus plants, the surface of the plants, and inside the plants as endophytic fungi. Aspergillus was the most common genus in all study areas. The highest number of genera and species of fungi were recorded in Aswan university campus followed by Aswan airport road. Fungal diversity analysis revealed that these two locations have higher fungal diversity compared to other two locations. A higher number of fungal species were isolated from rhizosphere soil and rhizoplane than from non-rhizosphere and other plant organs. Endophytic fungi were isolated from all plant parts of H. muticus. Communications between H. muticus plants and fungi under desert conditions both in rhizosphere and inside the plant are deduced.