Seed-borne fungi in domestic bird feed in Saudi Arabia

Seed-borne fungi from seeds of barley, canary, maize, oats, rice, rapeseed, red millet, sunflower, white millet and yellow millet were investigated. These seeds are available in the market as bird feed, supplied by companies in various countries as healthy and nutritious food for domestic birds. A total of 81 fungal species were isolated. The genusAspergillus was predominant with 23 species, followed byPenicillium with 18,Ulocladium with 7,Alternaria with 6 andChaetomium, Curvularia andDrechslera with 5 species each. Other genera isolated wereAureobasidium, Cladosporium, Fusarium, Mucor, Rhizopus andSyncephalastrum.     

Molecular phylogeny of date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia by DNA fingerprinting

Genetic diversity among 13 different cultivars of date palm (Phoenix dactylifera L.) of Saudi Arabia was studied using random amplified polymorphic DNA (RAPD) markers. The screening of 140 RAPD primers allowed selection of 37 primers which revealed polymorphism, and the results were reproducible. All 13 genotypes were distinguishable by their unique banding patterns produced by 37 selected primers. Cluster analysis by the unweighted paired group method of arithmetic mean (UPGMA) showed two main clusters. Cluster A consisted of five cultivars (Shehel, Om-Kobar, Ajwa, Om-Hammam and Bareem) with 0.59–0.89 Nei and Li's coefficient in the similarity matrix. Cluster B consisted of seven cultivars (Rabeeha, Shishi, Nabtet Saif, Sugai, Sukkary Asfar, Sukkary Hamra and Nabtet Sultan) with a 0.66–0.85 Nei and Li's similarity range. Om-Hammam and Bareem were the two most closely related cultivars among the 13 cultivars with the highest value in the similarity matrix for Nei and Li's coefficient (0.89). Ajwa was closely related with Om-Hammam and Bareem with the second highest value in the similarity matrix (0.86). Sukkary Hamra and Nabtet Sultan were also closely related, with the third highest value in the similarity matrix (0.85). The cultivar Barny did not belong to any of the cluster groups. It was 34% genetically similar to the rest of the 12 cultivars. The average similarity among the 13 cultivars was more than 50%. As expected, most of the cultivars have a narrow genetic base. The results of the analysis can be used for the selection of possible parents to generate a mapping population. The variation detected among the closely related genotypes indicates the efficiency of RAPD markers over the morphological and isozyme markers for the identification and construction of genetic linkage maps.Communicated by H.F. Linskens     

An alkali-soluble heteroxylan from seeds of Phoenix dactylifera L

Alkali-soluble polysaccharides, isolated from the seeds of dates, have been investigated using methylation and partial hydrolysis studies. The polysaccharides are shown to contain D-xylose and 4-O-methyl-D-glucuronic acid in a molar ratio of 5:1. An aldobiouronic acid from hemicellulose was characterized, and investigation revealed that the hemicellulose consists of a polymer of (1-->4)-linked D-xylopranosyl residues having branches of D-xylopyranosyl and 4-O-methyl-alpha-D-glucopyranosyluronic acid.     

A water-soluble galactomannan from the seeds of Phoenix dactylifera L

A water-soluble polysaccharide, isolated from the seeds of dates, has been investigated using methylation, periodate and CrO(3) oxidation, NMR spectroscopy, and reaction with Bandeiraea simplicifolia lectin and alpha-D-galactosidase. The polysaccharide consists of a backbone composed of (1-->4)-beta-D-mannopyranosyl residues and carries a single (1-->6)-alpha-linked D-galactopyranosyl residue.     

A neutral beta-D-glucan from dates of the date palm,Phoenix dactylifera L

Polysaccharides extracted from Libyan dates with hot water and 0.05 M NaOH were fractionated and purified by ion-exchange and gel-filtration chromatography. According to the methylation and hydrolysis analyses, the results indicate the D-glucan to be linear and to contain both (1-->3)- and (1-->4)-linkages. The anomeric NMR measurements confirm that the sugar residues are beta-glycosidically linked. This is the first report on the isolation of a neutral beta-D-glucan from dates.     

Viable airborne fungi in Riyadh, Saudi Arabia

An aerobiological study to identify and quantify allergenic fungi and their seasonal fluctuations was conducted at two different sites, (Al-Batha, a more developed area in the south and Al-Ulia, a less developed area in the north) in Riyadh city, using portable Personal Volumetric Air Sampler (Burkard Manufacturing Co., England). Sampling was conducted twice a week in both the morning and in the afternoon at both sites, for a period of 12 months. Airborne fungi were grouped into major and minor components depending upon their frequency of appearance and catch percentage in the air. Cladosporium spp., Penicillium spp., Aspergillus spp., Alternaria spp. and Ulocladium spp. were included as major components. Minor components included Drechslera spp., Rhizopus spp., Fusarium spp. and Stachybotryis spp. In general, higher concentrations of fungi were found at the developed (Al-Batha) site than at the less developed (Al-Ulia) site, both in the morning and in the afternoon.     

Mycotoxins producing fungi and mycoflora of air-dust from Taif,Saudi Arabia

Using the dilution plate method, 70 species and 31 genera were collected from 20 dust samples on glucose (28 genera and 64 species) and cellulose Czapek's agar (22 genera and 46 species) at 28° C. The most common fungi were Aspergillus niger, A. flavus, A. flavus var. columnaris, Phoma glomerata, Fusarium oxysporum, Penicillium chrysogenum and Mucor racemosus; and A. nidulans, Phoma humicola, Drechslera spicifera and Stachybotrys chartarum on the two media, respectively.Toxicity test showed that about 85% of the isolates tested were toxic to brine shrimp (Artemia salina). Thin layer chromatographic analysis revealed that 13 out of 23 toxic isolates produced known mycotoxins. Toxins identified were: aflatoxins B₁ and B₂, Kojic acid and trichodermine.     

In Vitro Multiplication of Phoenix dactylifera (L)

A method of microcloning via somatic embryogenesis was established in date palm (Phoenix dactylifera L) cultivars. The method has potential for commercial application. Embryogenic cultures were initiated from soft primordial tissues of 2-3-year-old female suckers. The system was optimized first for the genotype ’sayar’ and then its applicability was tested to other genotypes. A method of pre-acclimation using pre-acclimation chambers has been devised, which improved hardening survival greatly. More than 80 clones obtained from the genotype ’sayar’ have been shifted to field for agronomic evaluation.     

Molecular identification of isolated fungi from stored apples in Riyadh,Saudi Arabia

Fungi causes most plant disease. When fruits are stored at suboptimal conditions, fungi grows, and some produce mycotoxin which can be dangerous for human consumption. Studies have shown that the Penicillium and Monilinia species commonly cause spoilage of fruits, especially apples. Several other genera and species were reported to grow to spoil fruits. This study was conducted to isolate and identify fruit spoilage by fungi on apples collected in Riyadh, Saudi Arabia and conduct a molecular identification of the fungal isolates. Thus, we collected 30 samples of red delicious and Granny Smith apples with obvious spoilage from different supermarkets between February and March of 2012 in Riyadh, Saudi Arabia. Each apple was placed in a sterile plastic bag in room temperature (25–30 °C) for six days or until fungal growth was evident all over the sample. Growth of fungal colonies on PDA was counted and sent for molecular confirmation by PCR. Six fruit spoilage fungi were isolated, including Penicillium chrysogenum, Penicillium adametzii, Penicillium chrysogenum, Penicillium steckii, Penicillium chrysogenum, and Aspergillus oryzae. P. chrysogenum was the most frequent isolate which was seen in 14 of a total of 34 isolates (41.2%), followed by P. adametzii and A. oryzae with seven isolates each (20.6%) and the least was P. steckii with six isolates (17.6%). Penicillium species comprised 27 of the total 34 (79.4%) isolates. Sequence analysis of the ITS regions of the nuclear encoded rDNA showed significant alignments for P. chrysogenum, P. adametzii and A. oryzae. Most of these fungal isolates are useful and are rarely pathogenic; however they can still produce severe illness in immune-compromised individuals, and sometimes otherwise healthy people may also become infected. It is therefore necessary to evaluate the possible production of mycotoxins by these fungi to determine a potential danger and to establish its epidemiology in order to develop adequate methods of control.     

Structure, Composition and Physiological State of the Endosperm of Phoenix dactylifera L

The date endosperm consists of living cells with the same generalcellular structure throughout the seed. The major storage products,as shown by histochemical staining, are lipid, stored as numeroussmall lipid bodies which fill the cytoplasm, and protein, aslarge but variably-sized protein bodies. Nuclei are presentbut lack large amounts of heterochromatin. Plastids and mitochondriaare present but infrequently seen and have poorly developedinternal membranes. No endoplasmic reticulum or dictyosomesare present before or after hydration. The cell wall is thickexcept in areas of pit fields and consists of three layers whichdiffer in their staining behaviour: middle lamella, thickenedwall and inner wall. Both the endosperm and embryo of the imbibedseed undergo aerobic respiration, but the embryo respires ata more rapid rate than does the endosperm. A small area of theendosperm around the distal pole of the cotyledon shows histochemicallydetectable levels of succinic dehydrogenase. Phoenix dactylifera L, date palm, endosperm, ultrastructure, histochemistry, respiration, succinic dehydrogenase     

Osmophilic fungi of desert soils in Saudi Arabia

100 osmophilic species in addition to two varieties which belong to 38 genera were isolated from desert soils of Saudi Arabia. The most prevalent genera were Asperngillus, Altemaria, Penicillium, Cephalosporium, Acremonium and Botryotrichum which occurred in 55–97.5% of the samples contributing 1.8–45.2% of total fungi. From the preceding genera A. amstelodami, A. fumigatus, A. terreus, A. niger, A. flavipes, A. repens, A. alternata, P. notatum, P. chrysogenum, P. citrinum, C.? racifi, A. strictum and B. atrogriseum were the most common. Five genera were recovered in moderate frequency namely, Ulocladium, Fusarium, Drechslera, Microascus, Syncephalastrum and Cladosporium which emerged in 25–42% of the samples comprising 0.7–2.8% of total fungi. The results obtained in the present investigation reveal that the fungus flora of Saudi Arabian soils is of osmophilic nature.     

Halophilic fungi of desert soils in Saudi Arabia

Twenty-five genera and sixty-eight species, in addition to one variety of each of A. chevalieri, A. flavus and A. nidulans were isolated from 40 soil samples collected from desert in Saudi Arabia on 5% sodium chloride-Czapek's agar. The most frequent genera were Aspergillus (20 species + 3 varieties), Penicillium (14 species), Drechslera (2 species) and Ulocladium (3 species), followed by Stemphylium (1 species), Scopulariopsis (2 species), Trichoderma (1 species) Botryotrichum (2 species), Cladosporium (3 species), Myrothecium (1 species) and Alternaria (1 species). From these genra A. amstelodami, A. chevalieri, A. ruber, A. ochraceus, P. brevi-compactum, P. ?cyano-fulvum, P. notatum, D. spicifera, U. consortiale, S. botryosum, S. brevicaulis, T. viride, B. piluliferum, C. herbarum, M. verrucaria and A. alterata were the most common. The results obtained in this investigation reveal that the fungus flora of Saudi Arabian soils is of halophilic nature.     

Cellulose-decomposing fungi of desert soils in Saudi Arabia

Seventy-five species in addition to 5 varieties of cellulose-decomposing which belong to 27 genera were collected during this investigation. Aspergillus (12 species + 4 varieties), Alternaria (4 species), Stachybotrys (3 species + 1 variety), and Penicillium (12 species) were of high frequency of occurrence, of which A. fumigatus, A. niger, A. terreus, A. alternata, A. tenuissima, S. atra, P. citrinum and P. corylophilum were the most common. Six genera were of moderate frequency and these were Botryotrichum (2 species), Macrophomina (1 species), Drechslera (5 species), Ulocladium (4 species), Chaetomium (7 species) and Curvularia (4 species) of which B. atrogriseum, D. spicifera, D. sativus, Ubotrytis, C. spirale and C. lunata were the most prevalent. Five and twelve genera were recovered on cellulose-Czapek's agar plates in low and rare frequency of occurrence, respectively.     

Propagation of Date Palm (Phoenix dactylifera L.) in vitro

Adventitious plantlets were obtained from lateral buds, shoottips, embryos, and pieces of stem and rachilla tissue of Phoenixdactylifera L. cultured on a modified Murashige and Skoog mediumcontaining 3 mg l^–1 N-(²-isopenty)adenine 0?1–100mg l^–1 -naphthaleneacetic acid or 2,4-dichlorophenoxyaceticacid, and 3 g l^–1 activated charcoal. Additions of auxinswere necessary to induce explants to produce callus, adventitiousplantlets, and roots. Plantlets were obtained from explantscultured 3–4 months in vitro. No difference in growthresponses between male and female explants was observed duringculture. Complex addenda of activated charcoal and polyvinylpyrrolidonewere tested in the nutrient media at various concentrationsto prevent explant browning. Activated charcoal fostered satisfactorygrowth by reducing the browning and inhibition of growth ofexplants.     

Sensitivity Analysis of CLIMEX Parameters in Modeling Potential Distribution of Phoenix dactylifera L.

Using CLIMEX and the Taguchi Method, a process-based niche model was developed to estimate potential distributions of Phoenix dactylifera L. (date palm), an economically important crop in many counties. Development of the model was based on both its native and invasive distribution and validation was carried out in terms of its extensive distribution in Iran. To identify model parameters having greatest influence on distribution of date palm, a sensitivity analysis was carried out. Changes in suitability were established by mapping of regions where the estimated distribution changed with parameter alterations. This facilitated the assessment of certain areas in Iran where parameter modifications impacted the most, particularly in relation to suitable and highly suitable locations. Parameter sensitivities were also evaluated by the calculation of area changes within the suitable and highly suitable categories. The low temperature limit (DV2), high temperature limit (DV3), upper optimal temperature (SM2) and high soil moisture limit (SM3) had the greatest impact on sensitivity, while other parameters showed relatively less sensitivity or were insensitive to change. For an accurate fit in species distribution models, highly sensitive parameters require more extensive research and data collection methods. Results of this study demonstrate a more cost effective method for developing date palm distribution models, an integral element in species management, and may prove useful for streamlining requirements for data collection in potential distribution modeling for other species as well.     

Isolation of generative cells from pollen of Phoenix dactylifera

Summary Generative cells in pollen of Phoenix dactylifera had a convoluted surface and a small cytoplasmic volume, and condensed chromatin in the nucleus. Treatment of hydrated pollen with pectinase followed by grinding in a hypotonic medium released the generative cells from pollen. Convolutions of the plasma-membrane surface in vivo were retained by generative cells in vitro. Generative cells had a much lower solute concentration than did vegetative cells, a property that explains why hypotonic shock was effective in releasing intact generative cells from pollen.     

Dermatophyte and non dermatophyte fungi in Riyadh City,Saudi Arabia

BackgroundDermatophytes are a scientific label for a group of three genera (Microsporum, Epidermophyton and Trichophyton) of fungus that causes skin disease in animals and humans. Conventional methods for identification of these fungi are rapid and simple but are not accurate comparing to molecular methods.ObjectiveThis study aimed to isolate human pathogenic dermatophytes which cause dermatophytosis in Riyadh City, Saudi Arabia and to identify these fungi by using conventional and molecular methods.MethodsThe study was conducted in Medical Complex, Riyadh and King Saud University. Samples of infected skin, hairs and nails were collected from 112 patients. Diagnosis of skin infections, direct microscopic test, isolation and identification of dermatophytes by conventional and molecular methods were carried out.ResultsThe results indicated that the tinea capitis infection had the highest prevalence among the patients (22.3%) while Tinea barbae had the lowest. In this study the identified dermatophyte isolates belong to nine species as Trichophyton violaceum, Trichophyton verrucosum, Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton schoenleinii, Trichophyton concentricum, Microsporum canis, Microsporum audouinii and Epidermophyton floccosum which cause skin infections were isolated during this study. Non dermatophyte isolates included 5 isolates from Aspergillus spp. 4 isolates from Acremonium potronii and 15 isolates from Candida spp. M. canis were the most common species (25% of isolated dermatophytes). Out of the 52 dermatophyte isolates identified by conventional methods, there were 45 isolates identified by the molecular method.ConclusionsThe results concluded that approximately M. canis caused a quarter of dermatophyte cases, tinea capitis infection was prevalent and the molecular method was more accurate than conventional methods.     

Cultivation of oyster mushroom Pleurotus ostreatus on date-palm leaves mixed with other agro-wastes in Saudi Arabia

Promoting the use of agricultural waste is one of the newly prepared water and environment friendly agriculture strategies in the Kingdom of Saudi Arabia (KSA). The objective of this research was to study the efficiency of cultivating oyster mushroom (Pleurotus ostreatus) on date palm wastes mixed with other agricultural wastes available in KSA. Four agricultural wastes were mixed with date palm leaves at different ratios, with two supplements and three spawn rates were used. Wheat straw mixed with date palm at ratio of 25 (date palm): 75 (agro-waste) showed the best results in most of the parameters measured. Corn meal was superior over wheat bran as a supplement in all treatments. Parameter values increased with the increase of the spawn rate of P. ostreatus. Treatments with date palm leave wastes contained higher carbohydrates and fibers. No significant differences were found among the fruiting bodies produced on the different agro-wastes studied for the different proximates analyzed. Analyses of metal concentration showed that potassium was the highest in all the treatments tested followed by Na, Mg, Ca, and Zn. This is the first study that reported the success of growing oyster mushroom on date palm leaf wastes mixed with other agro-wastes obtainable in KSA.     

Purification and characterization of membrane-bound peroxidase from date palm leaves (Phoenix dactylifera L.)

Peroxidase from date palm (Phoenix dactylifera L.) leaves was purified to homogeneity and characterized biochemically. The enzyme purification included homogenization, extraction of pigments followed by consecutive chromatographies on DEAE-Sepharose and Superdex 200. The purification factor for purified date palm peroxidase was 17 with 5.8% yield. The purity was checked by SDS and native PAGE, which showed a single prominent band. The molecular weight of the enzyme was approximately 55 kDa as estimated by SDS–PAGE. The enzyme was characterized for thermal and pH stability, and kinetic parameters were determined using guaiacol as substrate. The optimum activity was between pH 5–6. The enzyme showed maximum activity at 55 °C and was fairly stable up to 75 °C, with 42% loss of activity. Date palm leaves peroxidase showed K_m values of 0.77 and 0.045 mM for guaiacol and H₂O₂, respectively. These properties suggest that this enzyme could be a promising tool for applications in different analytical determinations as well as for treatment of industrial effluents at low cost.