Mady A. Ismail

Deterioration and spoilage of peanuts and desiccated coconuts from two sub-Saharan tropical East African countries due to the associated mycobiota and their degradative enzymes

A broad variety of fungi (84 species belonging to 36 genera) were identified with more taxa infesting peanut seed samples from two tropical countries (29 genera and 61 species) compared to those found in desiccated coconuts (20 genera and55 species) on both DRBC and DG18 media. This may be due to the higher moisture levels in peanuts (5.07–7.97%) compared with coconuts (1.5–4.17%). More taxa and propagules were recovered on DG18 in both cases. The dominant fungi from both substrates on both isolation media were Aspergillus andPenicillium, with other fungi from only one substrate/medium. The aflatoxigenic species (A. flavus) dominated Kenyan samples more so than Ugandan samples on both substrates. However only71.5% and 87% of the peanut kernels, on DRBC and DG18, respectively, were found to be infested with fungi. The aflatoxigenic species (A. flavus/parasiticus)were found in 75% of the samples, however only 15.75% and 13%of the kernels analyzed were infested. The most frequently isolated species from peanuts were A. niger followed by A. flavus and M. phaseolina.E. repens, E. amstelodami,E. rubrum and E. chevalieri dominated peanut seeds on DG18, and R. stolonifer, A. parasiticus,F. solani, L. theobromae and P. chrysogenumon DRBC. The mean count of fungal propagules in coconut samples were approximately 0.7× 103 and 0.8× 103on DRBC and DG18, respectively, with a high proportion of those propagules recorded for the aflatoxigenic species (about 0.17×103 and 0.25× 103 colonies/g). The mycobiota of desiccated coconut was dominated by A. niger, A. flavusand P. chrysogenum. Also A. ochraceu,P. waksmanii, Paecilomyces variotii,P. islandicum and R. mucilaginosa were more frequent on DRBC, while, species of Cladosporium,Chrysosporium and Eurotium were more frequent on DG18.Enzyme indices (or the activities) for each specific strain, when determined after 5 and 8 days of incubation, proved to be similar. A recommendation is given. The proteolytic and lipolytic potentialities of the most commonly encountered species from both peanuts and coconuts were studied. The most interesting observation is that most of the positive isolates, in both commodities had high enzymic activity compared to those reported earlier for isolates of the same species. Such capabilities suggest that these commodities are expected to deteriorate, since climatic conditions in tropical areas favour fungal proliferation. Emphasis on the proper harvesting, drying, handling, transportation and/or storage; and also education of the populace, especially those are dealing with these foods, should be taken into consideration by the relevant authorities. The contaminated foods constitute a health hazard for human consumption.

Microbial populations, ammonification and nitrification in soil treated with urea and inorganic salts

Soil fertilization with urea at rates of 0.2 and 0.5 mg N/g soil was toxic for total counts of bacteria and fungi except with cellulolytic fungi where growth was promoted by addition of urea after 90-d incubation. Also, the population numbers of both bacteria and fungi were significantly decreased when soil was amended with CaCl2 and K2SO4 applied at two levels (50 and 100 μmol/g soil). Some alleviation of the toxic effect of either urea or the inorganic salts was observed when they were applied in combination. Fungal species composition was found to be affected in the treated soil. The most tolerant fungi wereAlternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Eurotium amstelodami, E. chevalieri, Nectria hœmatococca, Pœcilomyces variotii andStachybotrys chartarum. Other species of fungi were either sensitive to all treatments or sensitive to some and tolerant to others. Ammonium nitrogen was found to be more accumulated in soil treated with urea mixed with inorganic salts compared with soil treated only with urea whereas NO3−-N (and NO2−-N) was decreased. The overall effect of the addition of inorganic salts on total mineralized nitrogen, however was promotive. Soil pH was increased in ureatreated soil but was depressed by application of CaCl2 or K2SO4 to values lower than that of untreated soil. The results may be of agronomical interest in overcoming problems encountered with urea application as N fertilizer.

Antimicrobial activity of latex silver nanoparticles using Calotropis procera

ABSTRACT Objective To synthesize silver nanoparticles (AgNPs) by green methods using serum latex of Calotropis procera at 80 °C and evaluate them against bacteria, dermatophytes and phytopathogenic fungi comparing with the activity of untreated latex. Methods The synthesis of AgNPs was performed by mixing 3% latex serum extract with the same volume of silver nitrate (2 mmol/L) solution in round flask and heating in water bath at 80 °C. Characterization of silver particles were determined using UV-vis spectrophotometer, transmission electron microscopy (TEM), X-ray diffraction and Fourier transform infrared spectroscopy. The antimicrobial activity of the green synthesized AgNPs was determined against bacteria, dermatophytes and phytopathogenic fungi and compared to the crude untreated latex by agar-well diffusion methods. Results Biosynthesis of latex silver nanoparticles was successfully obtained by green method. The formation of AgNPs has been confirmed by UV-vis, TEM microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. TEM analysis showed that synthesized AgNPs are highly stable spherical shaped particles, well dispersed with a diameter ranged from 4 nm up to 25 nm and an average size of 12.33 nm. AgNPs showed strong antibacterial activity against Gram-negative bacteria ( Escherichia coli , Pseudomonas aeruginosa and Serratia sp.) and antifungal activity against Trichophyton rubrum , Candida albicans and Aspergillus terreus . Conclusions It can be concluded that serum latex of Calotropis procera was found to display strong potential for the synthesis of AgNPs as antimicrobial agents through rapid reduction of silver ions (Ag + to Ag 0 ). The green synthesized AgNPs were found to show higher antimicrobial efficacy than crude latex.

Preliminary surveys of outdoor and indoor aeromycobiota in Uganda.

This investigation was conducted during the period of March through June 1998 to trap, enumerate and identify the different airborne fungi in a variety of microhabitats of outdoor and indoor environments in different localities of Uganda. The settle plate method was used and Czapek-Dox agar was the isolation medium. A total of 47 genera and 61 species in addition to some other unidentified airborne fungi were trapped from all exposures at outdoor (39 genera and 52 species) and indoor (35 and 49) environments. The total fungal catches of outdoor airspora obtained from all exposures (and even in most individual exposures) were more than twice (5222 colonies) of that of the indoor ones (4361) when the exposure periods are taken into consideration. It is worth mentioning that the most highly polluted sites were either parks, forests or river banks for outdoor exposures, or teaching laboratory, library, laterines or bathrooms for indoor exposures. The most prevalent fungi from both outdoor and indoor microhabitats being species of Mycosphaerella, Yeasts, Penicillium, Fusarium, Aspergillus,Cochliobolus and Alternaria. However, several others were trapped frequently from either outdoor or indoor environments. On the other hand, several others were trapped only, but not frequently (in low or rare instances) from either outdoor or indoor microhabitats. The implications of these airborne spores are also discussed.

Fungi associated with the Egyptian cotton leafwormSpodoptera littoralis Boisdoval

A total of 28 species representing 15 fungal genera were found to be associated with the all different stages of the Egyptian cotton leafworm,Spodoptera littoralis Boisd., its faeces and the air of the containers where it was reared on Czapek Dox agar medium at 28°C.Aspergillus was the most common genus and was frequently isolated from all substrates.A. flavus was the only fungus associated with all insect stages. At least two well known facultative pathogens were obtained:Beauveria alba andCephaliophora tropica. Nearly all fungi recovered from insect faeces or its environment were also encountered from different insect stages. Forty-two isolates were tested for their abilities for growth on a synthetic medium (nitrogen- and carbon-free) containing partially purified chitin. Most (76.2%) had moderate growth rates.

Evaluation of the mycological status of luncheon meat with special reference to aflatoxigenic moulds and aflatoxin residues

The luncheon meat samples analyzed, which were produced locally by the two main luncheon meat producing companies in Egypt were relatively highly contaminated either by moulds and yeasts in general, aflatoxigenic species and aflatoxin residues in particular. The most frequently encountered fungi from the samples were yeasts, Aspergillus niger, A. flavus, Penicillium chrysogenum, Rhizopus stolonifer, Mucor circinelloides. Less common were Cladosporium sphaerospermum, Alternaria alternata, Mycosphaerella tassiana, P. aurantiogriseum and P. oxalicum. The most important aflatoxigenic species, A. flavus, was isolated frequently. It was 10% of the total fungal isolates from both samples of the two companies. Seven luncheon meat samples out of 50 analyzed were positive for aflatoxin B1 or B1 and G1, while all samples were negative for aflatoxins B2, G2, M1 and M2. Aflatoxin B1 was detected only in 4 and 3 samples out of 25 analyzed from each of company A and B, respectively. The highest detectable level, 11.1 ppb, was recorded in a sample from company B and the least, 0.5 ppb, in a sample from company A. Aflatoxin G1, at concentration of 3.2 ppb, was detected in only one sample of the aflatoxin B1 – contaminated 3 samples of company B: this sample also had the highest level of aflatoxin B1. Some luncheon meat samples had higher numbers of aflatoxigenic A. flavus than others, however these samples were negative for aflatoxins. The hazardous potential of such contamination will be discussed.

Antioxidant and antiapoptotic activities of Calotropis procera latex on Catfish (Clarias gariepinus) exposed to toxic 4-nonylphenol.

Calotropis procera L. is known as medicinal plant. The Phytochemical analyzes of its latex revealed that it possessed antioxidants, namely terpenes, phenolic compounds and cardenolides, flavonoids and saponins, while tannins, alkaloids and resin were absent in moderate to high concentration. In the present study, the role of latex of Calotropis procera as antioxidant and antiapoptotic was reported. To carry out this aim, fishes were exposed to 100 µg l(-1) 4-nonylphenol as chemical pollutant. The enzymes, superoxidase dismutase, catalase, acetlycholinstrase (AchE), glutathione s-transferase, cortisol, G6PDH) and apoptotic cells increased significantly (p<0.05) accompanied by irregular disturbance of (Na(+), K(+)) ions in the presence of 4-nonylphenol. On the other hand, these enzymes, ions, and apoptotic cells decreased normally and significantly (p<0.05) in the presence of latex. Total phenol content, total capacity antioxidant, reducing power decrease significantly (p<0.05) in the presence of 4-nonylphenol and increase normally in the presence of latex. Latex was used for the first time to protect catfish after 4-nonylphenol exposure. Our study confirms that crude latex of Calotropis procera possessed antioxidant and antiapoptotic activities against the toxicity of 4-Nonylphenol.

Keratinophilic and other fungi isolated from combine harvester wheat and sorghum dusts and from the atmosphere of winnow sites in Egypt.

Three methods were used for the isolation of fungi in the present investigation: the dilution-plate method, hair-baiting technique with horse hairs and the “exposed plate” method. Sabourauds glucose agar at 28 °C was also used as isolation medium. 102 species and 2 species varieties belonging to 36 genera were collected from combine harvester wheat and sorghum dusts and from the atmosphere of hay or winnow sites.Chrysosporium was represented by 6 species:C. asperatum, C. indicum, C. keratinophilum, C. merdarium, C. pannorum andC. tropicum. Several filamentous fungi tolerating high levels of cycloheximide and other moulds were frequently encountered in the two types of dusts and in the two atmospheres, such as members ofAcremonium, Alternaria, Aspergillus, Cladosporium, Emericella, Eupenicillium, Fusarium, Paecilomyces, Penicillium, Piedraia, Rhizopus, Scopulariopsis and others.

Confirmation of the relationships of Aspergillus egyptiacus and Emericella nidulans using progesterone transformation

Isolates of Emericella nidulans (7 isolates), Aspergillus egyptiacus (7) and A. versicolor (5) were tested for their ability to transform progesterone. Consistent results were obtained between isolates of the same species. Whilst A. egyptiacus and E. nidulans possessed the enzyme system catalysing the transformation of progesterone into 11‐α‐hydroxyprogesterone, A. versicolor did not. Thus, progesterone transformation could be considered as further diagnostic evidence that A. egyptiacus is related to the Emericella group.

Bacterial and fungal endophthalmitis in Upper Egypt: related species and risk factors

OBJECTIVE To study risk factors, contributing factors of bacterial and fungal endophthalmitis in Upper Egypt, test the isolated species sensitive to some therapeutic agents, and to investigate the air-borne bacteria and fungi in opthalmology operating rooms. METHODS Thirty one cases of endophthalmitis were clinically diagnosed and microbiologically studied. Indoor air-borne bacteria and fungi inside four air-conditioned operating rooms in the Ophthalmology Department at Assiut University Hospitals were also investigated. The isolated microbes from endophthalmitis cases were tested for their ability to produce some extracellular enzymes including protease, lipase, urease, phosphatase and catalase. Also the ability of 5 fungal isolates from endophthalmitis origin to produce mycotoxins and their sensitivity to some therapeutic agents were studied. RESULTS Results showed that bacteria and fungi were responsihle for infection in 10 and 6 cases of endophthalmitis, respectively and only 2 cases produced a mixture of bacteria and fungi. Trauma was the most prevalent risk factor of endophthalmitis where 58.1% of the 31 cases were due to trauma. In ophthalmology operating rooms, different bacterial and fungal species were isolated. 8 bacterial and 5 fungal isolates showed their ability to produce enzymes while only 3 fungal isolates were able to produce mycotoxins. Terbinafine showed the highest effect against most isolates in vitro. CONCLUSIONS The ability of bacterial and fungal isolates to produce extracellular enzymes and mycotoxins may be aid in the invasion and destruction of eye tissues. Microbial contamination of operating rooms with air-borne bacteria and fungi in the present work may be a source of postoperative endophthalmitis.