Farida T. El-Hissy

Studies on aquatic fungi in Delta Region (Egypt)

Summary 117 species and 2 varieties related to 2,712 colonies in addition to 991 unidentified colonies of the genera Achlya, Saprolegnia, Pythium and Phytophthora were recovered in this investigation. The richest season (94 species, 1,018 colonies) was autumn and the poorest (58 species, 720 colonies) was summer. The richest samples were generally characterized by comperatively high amounts of organic matter, high oxygen content, low contents of salts and low to moderate temperature. The pH value did not show any regular seasonal variation and did not exhibit any considerable influence on fungal population. The fungal species which possess centric or subcentric oospores prevailed in low or moderate temperature season and those which possess eccentric oospores prevailed in summer season. 12 species disappeared completely in summer and 7 in winter. Some species appeared only in spring and autumn and others appeared althrough the year. In estuarine sites of both Nile branches, no Saprolegniaceae appeared in salinity exceeding 1.5% whereas some species which belong to Peronosporales and Chytridiales appeared but only in a limited occurrence.

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. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Aquatic fungi associated with seven species of nile fishes (Egypt)

Ten identified species in addition to 2 unidentified species of Achlya and Pythium which belong to seven zoosporic fungal genera (aquatic freshwater fungi) were recovered during this investigation. The fish species with most zoosporic fungi (5 species and 3 genera) was Tilapia nilotica. The fish species with least fungi were Bagrus bayad and Syndontis schall (yielded only one species each). Mormyrus kannum did not give any zoosporic fungal species. Some aquatic fungi emerged only from internal organs of some fish species. 46 species belonging to 22 terrestrial fungal genera were also recovered during this work. The broadest spectrum (15 species) was recorded in the second external wash water (WE2) of Mormyrus kannum and the narrowest spectrum (2 species) in the second internal wash water (WI2) of Schilbe mystus and with the scales of Labeo niloticus. First wash water of internal organs (WI1) of Tilapia nilotica yielded the highest total count (6.95% of total count) and the second wash water of internal organs (WI2) of Schilbe mystus yielded the lowest total count (0.34% of total count). Nile water sample (NW) yielded 3.67% of total fungi and eight species which belong to seven genera. Aspergillus was the most common (31 out of 31 samples) and yielded 52.40% of total fungi. It was represented by 12 species and one variety of A. flavus var. columnaris (broadest spectrum). Penicillium was represented by 7 species and found in 19 out of 31 samples yielding 11.02% of total fungi.

Effect of level of relative humidity on fungi and germinability of Egyptian peanut seeds

Summary The changes in the composition of peanut seed-borne fungal flora at various levels of relative humidity (40–100%) were investigated. The total count of fungi significantly increased at all levels of relative humidity and the climax was recorded during the last period at 100 %. Aspergillus was the main component of fungal flora, arising in stored seeds. A. fumigatus was the dominant fungal species at 40–80%, but was surpassed by A. flavus at 100 % r.h., A. terreus and A. ochraceus were also good colonizers of peanut seed. A. sydowii, which possessed the highest initial population, could not compete with other fungi and was almost completely lost at all levels of relative humidity. Penicillium, represented mainly by P. funiculosum, could only markedly increase its population at 100% r.h.; Rhizopus stolonifer was also an active invader of peanut seeds at 100 % r.h. When the isolation plates were incubated at 45°C, the results were basically similar. Aspergillus fumigatus was the most dominant fungal species, except at 100% r.h. where it was exceeded by A. flavus. Humicola grisea var. thermoidae, Scopulariopsis brevicaulis, Mucor pusillus, Sporo-trichum thermophile, Thermoascus aurantiacus, and Thielavia sepedonium were isolated only when the plates were incubated at 45°C. At all levels of relative humidity, the germinability of seeds declined slowly or rapidly with the extension of the storage period and the rate of decline was enhanced with the rise of the relative humidity. Complete loss of germinability was recorded after 30 days at 100% and after 180 days at 80% r.h.

Aquatic fungi from the submerged mud of Aswan High Dam Lake

Abstract Twenty five identified and four unidentified aquatic fungal species which belong to eleven genera of aquatic fungi were recovered from one hundred samples of the submerged mud which were collected randomly from the margins at different localities of Aswan High Dam Lake banks during the period from May 1992 to October 1992. The richest submerged mud samples in aquatic fungi were characterized by somewhat alkaline pH ranging between 7.1 and 7.9 and by low amounts of total soluble salts (1.9–2.9 mg/100 g mud sample) and low organic matter (1.6–0.4 mg/100 g). Approximately 54% of the mud samples yielded only one aquatic fungal species per sample. Pythium and Saprolegnia were the commonest aquatic fungal genera recovered during this investigation, whereas Leptomitus and Nowakowskiella were less frequent.

Aquatic phycomycetes from egyptian soil (Delta Region)

Abstract Seventy identified and six unidentified species in addition to 5 varieties which belong to 30 genera of aquatic phycomycetes were recovered from 220 soil samples collected randomly from different localities in the Nile Delta and Suez canal regions including eleven governorates during November 1991. The highest number of aquatic fungal genera and species was obtained from El-Sharkya (24 identified and 4 unidentified species in addition to two varieties belonging to 14 aquatic fungal genera) and El-Dakahlia (24 identified and 4 unidentified species in addition to two varieties belonging to 13 aquatic fungal genera) Governorates, whereas the lowest was from Port-Said (13 identified and 2 unidentified species in addition to one variety belonging to 11 aquatic fungal genera).Pythium(high occurrence),Allomyces(moderate occurrences),Nowakowskiella, Aqualinderella, Achlya, Phytophthora, Olpidiopsis, DictyuchusandBlastocladiopsis(low occurrence each) were the most frequent aquatic fungal genera recovered during this investigation, whileAllomyces anomalus, Aqualinderella fermentans, Nowakowskiella elegans, Olpidiopsis brevispinosaandBlastocladiopsis parvawere the prevalent species. Soil samples which were characterized by relatively low temperature, high contents of organic matter and low total soluble salts were the richest in aquatic phycomycetes and vice versa.

Effect of the fungicide chlorothalonil (Bravo) on some metabolic activities of aquatic fungi

Physiological responses ofAchlya proliferoides, Saprolegnia ferax andDictyuchus sterilis as affected by the fungicide chlorothalonil (Bravo) were determined. Glucose consumption differed in dependence on the organisms used. Ammonia and peptide nitrogen secretion were stimulated inS. ferax but inhibited in the other two organisms. All doses of the fungicide used decreased phosphorus absorption and increased acid phosphatase activity. The lowest concentrations (30 ppm) of the fungicide increased DNA, RNA and protein synthesis while inhibition was observed at moderate or high concentrations. Aspartate aminotransferase and alanine aminotransferase activities were inhibited inA. proliferoides, stimulated inS. ferax but remained similar to that of the control inD. sterilis.

Effect of Some Heavy Metals on the Mycelial Growth of Achlya racemosa and Alatospora acuminata

Summary Achlya racemosa and Alatospora acuminata cultures were subjected to various levels of NiCl2, CdCl2, Pb(NO3)2 and CuSO4. The mycelial dry weight of two fungal species decreased with the raise of the levels of all heavy metal salts used. The toxicity of these heavy metals correlated to some abiotic factors such as pH, temperature and organic matter (peptone and yeast extract) was examined. The toxicity of NiCl2, Pb(NO3)2 and CuSO4 was reduced with the raise of pH value irrespective to either dose used or the fungus tested whereas toxicity of CdCl2 was enhanced. The raise of temperature than 20 °C induce the toxicity of all tested heavy metals. Increasing the concentrations of either peptone or yeast extract from 0.25 to 1.50 % reduce the toxicity of four tested heavy metals whatever the dose used.

Selective effects of three herbicides on the fungus flora of egyptian soil

Abstract2,4-D (2,4-dichlorophenoxyacetio acid) when applied to the soil at three doses (1.9, 7.6 and 15.2 mg per kg dry soil) had a stimulating effect on the total count of soil fungi and on several fungal species especially between 5 and 20 d after treatment. When the herbicide was incorporated in the agar medium it had a stimulating effect on the counts of total fungi, Aspergillus sp., A. niger, A.fumigatus and Fusarium app. at the low dose (6.3 ppm), but wag toxic at this dose toward Humicola grisea and Myrothecium verrucaria at the medium and high doses (25.2 and 50.4 ppm), it was toxic to the total count of fungi and to the majority of fungal species.VCS-438 [2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-3,5-dione] was beneficial to the total count of fungi 2 and 5 d after soil treatment with the medium dose (8.0 mg per kg dry soil). Some fungal species could benefit from the low and the high doses (2.0 and 16.0 mg per kg dry soil) after these experimental periods. In the agar medium the counts of total fungi, Aspergillus sp., A. niger and A.fumigatus were almost significantly reduced by the three doses (6.8, 27.2 and 54.8 ppm).Planavin (4-methylsulphonyl-2,6-dinitro-N,N-dipropylaniline) was stimulating for the total count of fungi, Aspergillus, A.niger and A.ochraceus 2 and 5 d after treatment with the medium dose (8.0 mg per kg dry soil), and was also stimulating to Fusarium population at the medium dose after 2 d and at the high dose (16 mg per kg dry soil) after 20 d. In the agar medium Planavin at the low dose (6.8 ppm) was stimulating to A.terreus and inhibitory to A.nidulans and A.fumigatus. The medium and high doses (27.2 and 54.8 ppm) were generally toxic to the total count of fungi.

Aquatic phycomycetes recovered from Aswan High Dam Lake [AHDL]

Abstract Twenty five identified and four unidentified species belonging to eleven genera of aquatic phycomycetes were recovered from one hundred and thirty surface water samples which were collected mainly from Aswan High Dam Lake (100 samples) in addition to few samples from Aswan reservoir (10 sample) and the main stream of the River Nile at Aswan (20 samples) during the period from January to June, 1992. The richest water samples in aquatic phycomycetes species were those characterized by relatively low temperatures (15.9 °C-20.3 °C) and pH ranged between 7.4 – 8.3. The poorest samples were characterized by relatively high temperature (20.6°C-33.1°C). pH values fluctuating between 6.3 and 9.2, dissolved oxygen varying from 4.5 to 10.6 mg/L, total soluble salts ranging from 149 to 303 mg/L and the organic matter content between 2.0 and 51.1 mg/L. Saprolegina and Pythium were the most frequent aquatic fungal genera recovered during this investigation whereas Aphanomyces, Dictyuchus, Pythiopsis, Leptomitus, Allomyces and Blastocladiopsis were less frequent.