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Nora, Saudi Arabia

Alkahtani M.,Prince Nora University | El-Naggar M.A.,Prince Nora University | Eman S.A.O.,Al Baha University | Abedl-Kareem M.,Egyptian Plant Pathology Research Institute | Ammar M.F.,King Khalid University
American Journal of Food Technology

The study concentrated on the common associated fungi with date palm (Phoenix dactylifera L.) fruits with special reference to Fusarium isolates. Also, the ability of Fusarium isolates to produce different mycotoxins and their effect on specific biochemical components and quality aspects of date fruits. The pathogenic capability of twenty-six isolates of F. moniliforme (F. verticillioides) isolated from different date fruit cultivars were carried out in vitro. Mycotoxins were estimated by immune-affinity column. Biochemical changes as amino acids, water soluble vitamins and fat soluble vitamins were determined with HBLC in all treatments. The most isolated fungi were obtained from Hayani cv. which were belonging to 10 genera and 23 species from all tested cultivars. Fusarium moniliforme were the most prevalent and recorded the highest frequency percentages compared with other isolated Fusarium species. Fumonisin was the highest toxin in tested date cultivars followed by T-2 and Zearalenone. The high amount of mycotoxins was found in Hayani, Samani and Zaghlol cultivars, respectively. Artificial inoculation by F. moniliforme induced several biochemical changes. This toxic isolate caused a reduction in protein, total sugar, fat and fiber contents comparing with control and non-toxigenic isolate. Moreover, there were differences in the fractions of amino acid and Vitamins content of the tested isolates. Date palm fruits may be attacked by toxigenic Fusarium moniliforme isolates. This contamination led to reduction in quality of date fruits due to loss of their nutrients as the result of biochemical change. © 2011 Academic Journals Inc. Source

Alkahtani M.D.F.,Prince Nora University | Mazen M.M.,Egyptian Plant Pathology Research Institute | El-Naggar M.A.,Research Center Laboratory | Arfa M.K.,Egyptian Plant Pathology Research Institute
Journal of Plant Sciences

Mycotoxins is a serious problemthreatening human and animal health and detection is the most important steps to get rid of them. The impact of these mycotoxins on seed physiological characteristics as discoloration is important things that are related with seed quality as well as marketing. The fungal isolation was conducted from three cultivars of bean seeds (Giza g, Giza 4 and Giza 6) after dividing into groups depending on their color. Sixteen fungal species were associated with discolored bean seed samples. The Aflatoxin (AF), Alternariol (AOH) and Zearalenone (ZON) were determined using immunoaffinity columns and GC-MS. Aflatoxin was existed in all colored seeds while, the dark brown colored seeds contaminated with AF, AOH and ZON. The highest concentration was found in dark brown colored seeds followed by golden brown. However, Zearalenone (ZON) was detected only in the dark brown in high concentration (45 jag kg -1 seeds). AOH toxin excreted by both isolates of A alternata ran ged from 1.0 to 3.0 jj,g g -1. The highest level of AOH toxin has been detected after 14 days of incubation and then decreased. Whereas, the normal seeds contained the lowest concentration of Aflatoxin. The amount of Aflatoxin produced by A parasiticus increased positively with increasing incubation time. The amount reached 200 (p,g kg -1) after 35 days incubation. Nevertheless, this amount was decreased to 125 (p,g kg -1) after some period when bean seeds simultaneously inoculated with A alternata and A parasiticus. In conclusion mycotoxins affect on the seed physiology, there is a direct relationship between the rate of mycotoxins (AF, AOH and ZON) contamination and the degree of discoloration. The presence of more than fungus together may result in lack of mycotoxins content. © 2011 Academic Journals Inc. Source

El-Naggar M.A.,Research Central Laboratory | El-Naggar M.A.,Egyptian Plant Pathology Research Institute | Alkahtani M.D.F.,Prince Nora University | Thabit T.M.,Research Central Laboratory | And 2 more authors.
Foodborne Pathogens and Disease

Date palm (Phoenix dactylifera L.) is considered the main crop in deserts and arid areas such as Saudi Arabia. Five Streptomyces species and other fungal species were isolated from date palm rhizosphere soil of several cultivars, such as Barhi, Khalas, Sullaj, and Sukkari, in the Ghat and El-Gouf regions. Streptomyces strains were isolated on Biolog universal growth agar medium and were identified following Biolog methods. The predominant Streptomyces isolated from this present survey was S. plicatus followed by S. rimosus, S. rutgersensus, and S. griseus. The number of soilborne fungi in the tested soil decreased with the increased number of isolated Streptomyces. There was a significant positive correlation between the date palm cultivar and the number of isolated Streptomyces. The in vitro effects of isolated Streptomyces species on some toxigenic fungi were also studied. Enzyme-linked immunosorbent assay, immunoaffinity column chromatography, and high-performance liquid chromatography were used to study the mycotoxins. The concentration of most of the tested mycotoxins was reduced significantly with the presence of the Streptomyces isolates. Results indicate that some Streptomyces isolates established in date palm rhizosphere have the ability to reduce production of mycotoxins of some toxigenic fungi; thus they have the potential of reducing the subsequent disease occurrence. Therefore they can be applied in wider range as biocontrol agents. © Copyright 2012, Mary Ann Liebert, Inc. Source

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