Ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams

The biodiversity and richness of keratinophilic fungal communities including dermatophytes were assessed in three stream sites and three swimming pools in the Nablus district in Palestine, using hair baiting (HBT) and surface dilution plate (SDP) techniques, over 8- and 6-month periods, respectively. The effect of wastewater effluent and selected ecological factors on these fungi in relation to species diversity and population densities were also considered. Fifty keratinophilic fungal species were recovered from the aquatic habitats studied, of which 42 were recovered from stream sites and 22 from swimming pools. Of these fungi 6 were either dermatophytes (Microsporum gypseum, and Trichophyton mentagrophytes) or dermatophyte related species (Chrysosporium merdarium, Ch. tropicum, Ch. keratinophilum and T. terrestre). The most frequently isolated species in the three pools were Acremonium strictum and Cladosporium cladosporioides, using Sabouraud dextrose agar medium (SDA). The most abundant species were Acr. strictum, and Aspergillus flavus. However, only 4 species were isolated using the SDA medium amended with 5-flurocytosine (5-FC). The most frequent and abundant species in the three stream sites using SDA medium were Geotricum candidum, and Penicillium chrysogenum. The most frequent species in the three sites using the 5-FC medium, was Paecilomyces lilacinus. Using HBT, the most abundant and frequent species in the three stream sites were G. candidum, and Pa. lilacinus, on SDA medium, and Pa. lilacinus, and Gliocladium nigrovirens on the 5-FC medium. The 5-FC medium was more suitable for the isolation of dermatophytes and closely related species than the SDA medium; 6 were recovered on 5-FC, whereas only one on the SDA medium. Variation in the levels of keratinophilic fungal populations from the three stream sites sampled 5 times over an 8-month period, followed comparable fluctuation patterns. Wastewater affected fungal population densities with the highest levels in the un-polluted stream sites, and lowest in the heavily polluted sites. Swimming pools, polluted and un-polluted stream sites were found to be rich in pathogenic and potentially pathogenic fungi.     

Distribution,occurrence and characterization of entomopathogenic fungi in agricultural soil in the Palestinian area

The occurrence of entomopathogenic fungi was investigated in irrigated vegetable fields and citrus orchards soils, over a nine-month period (April-December 1999),using the Galleria bait method (GBM). Entomopathogenic fungi were found to occur in 33.6% of the soil samples studied, with positive samples yielding 70 fungal isolates, belonging to 20 species from 13 genera. Conidiobolus coronatus was the most frequent and abundant entomopathogenic species recovered, comprising 31.4% of the total number of isolates. Soil pH, soil moisture content and the geographical location had minor or no effect on the isolation of entomopathogenic fungi in the fields studied. On the other hand, organic matter content of soil, and vegetation type were found to significantly affect the occurrence of entomopathogenic fungi in soil habitats, with orchard fields yielding larger numbers of isolates than vegetable fields. Using Koch's postulates the pathogenicity of fungal isolates to Galleria larvae was found to range from 16–100% (mortality rate). Isolates of C. coronatus proved to be the most virulent isolates recovered. The effect of media and temperature on mycelial growth rate, conidial production and conidial germination of six entomopathogenic fungal species (C. coronatus, Entomophaga grylli, Erynia castrans, Hirsutella jonesii, Paecilomyces farinosus and Sporodiniella umbellata) was also studied. Mycelial growth rate, spore production and spore germination were significantly affected by media, temperature and isolates. In view of the present results, C. coronatus appears to be a good candidate for pest control in agricultural soils, as it has a wide tolerance to agricultural practices, has frequently been isolated from both vegetable and orchard fields, and is characterized by high mycelial growth rate, conidial production and conidial germination.This revised version was published online in October 2005 with corrections to the Cover Date.     

Influence of GTP/GDP and magnesium ion on the solvated structure of the protein FtsZ: a molecular dynamics study

We present here a structural analysis of ten extensive all-atom molecular dynamics simulations of the monomeric protein FtsZ in various binding states. Since the polymerization and GTPase activities of FtsZ depend on the nature of a bound nucleotide as well as on the presence of a magnesium ion, we studied the structural differences between the average conformations of the following five systems: FtsZ-Apo, FtsZ-GTP, FtsZ-GDP, FtsZ-GTP-Mg, and FtsZ-GDP-Mg. The in silico solvated average structure of FtsZ-Apo significantly differs from the crystallographic structure 1W59 of FtsZ which was crystallized in a dimeric form without nucleotide and magnesium. The simulated Apo form of the protein also clearly differs from the FtsZ structures when it is bound to its ligand, the most important discrepancies being located in the loops surrounding the nucleotide binding pocket. The three average structures of FtsZ-GTP, FtsZ-GDP, and FtsZ-GTP-Mg are overall similar, except for the loop T7 located at the opposite side of the binding pocket and whose conformation in FtsZ-GDP notably differs from the one in FtsZ-GTP and FtsZ-GTP-Mg. The presence of a magnesium ion in the binding pocket has no impact on the FtsZ conformation when it is bound to GTP. In contrast, when the protein is bound to GDP, the divalent cation causes a translation of the nucleotide outwards the pocket, inducing a significant conformational change of the loop H6-H7 and the top of helix H7.     

Traditional knowledge of wild edible plants used in Palestine (Northern West Bank): A comparative study

Background

A comparative food ethnobotanical study was carried out in fifteen local communities distributed in five districts in the Palestinian Authority, PA (northern West Bank), six of which were located in Nablus, two in Jenin, two in Salfit, three in Qalqilia, and two in Tulkarm. These are among the areas in the PA whose rural inhabitants primarily subsisted on agriculture and therefore still preserve the traditional knowledge on wild edible plants.

Methods

Data on the use of wild edible plants were collected for one-year period, through informed consent semi-structured interviews with 190 local informants. A semi-quantitative approach was used to document use diversity, and relative importance of each species.

Results and discussion

The study recorded 100 wild edible plant species, seventy six of which were mentioned by three informants and above and were distributed across 70 genera and 26 families. The most significant species include Majorana syriaca, Foeniculum vulgare, Malvasylvestris, Salvia fruticosa, Cyclamen persicum, Micromeria fruticosa, Arum palaestinum, Trigonella foenum-graecum, Gundelia tournefortii, and Matricaria aurea. All the ten species with the highest mean cultural importance values (mCI), were cited in all five areas. Moreover, most were important in every region. A common cultural background may explain these similarities. One taxon (Majoranasyriaca) in particular was found to be among the most quoted species in almost all areas surveyed. CI values, as a measure of traditional botanical knowledge, for edible species in relatively remote and isolated areas (Qalqilia, and Salfit) were generally higher than for the same species in other areas. This can be attributed to the fact that local knowledge of wild edible plants and plant gathering are more spread in remote or isolated areas.

Conclusion

Gathering, processing and consuming wild edible plants are still practiced in all the studied Palestinian areas. About 26 % (26/100) of the recorded wild botanicals including the most quoted and with highest mCI values, are currently gathered and utilized in all the areas, demonstrating that there are ethnobotanical contact points among the various Palestinian regions. The habit of using wild edible plants is still alive in the PA, but is disappearing. Therefore, the recording, preserving, and infusing of this knowledge to future generations is pressing and fundamental.     

Hair and scalp mycobiota in school children in Nablus area

Hair and scalp mycobiota of 1389 clinically normal children aged 6–12 years attending 12 schools in the Nablus District, Palestinian Authority, was assessed on three occasions over 8-month period (October 1998–May 1999) using the hair brush technique. One hundred and one fungal species belonging to 33 genera were recovered: 6 dermatophytes, 16 dermatophyte-like keratinophilic fungi, and 79 other keratinophilic fungal species. Species varied considerably in their frequency of occurrence and abundance based on their relative importance values (RIVs). The most frequent and abundant species were: Cladosporium cladosporioides, Cl. herbarum, Penicillium chrysogenum and Aspergillus flavus. Microsporum canis, Aphanoascus fulvescence and Chrysosporum sulfureum were the most frequent and abundant species of all dermatophytes and dermatophyte-like keratinophilic fungi recovered. The most frequent and abundant dermatophytes in different communities were M. canis in rural (RIV 0.87) and urban children (0.45), and Trichophyton violaceum (1.41) in refugee camp children. Chrysosporium species were the most frequent and abundant dermatophyte-like keratinophilic fungus in children from all localities followed by Aphanoascus fulvescence. Comparable results on the frequency and abundance of human hair and scalp mycobiota component fungi were obtained based on age group and sex of children. Higher number of species was recovered in spring months (73 species) than in autumn (57) and winter (44) months. Similar occurrence pattern was also noted for dermatophyte-like keratinophilic species and dermatophytes. Higher percentages of children with moderate (11–50) and heavy (≤ 50) spore loads (7.54 and 0.73, respectively) were found in urban school children community than in rural and refugee camp school children (4.7 and 0.1, respectively). Also significantly higher light (1–10) spore load percentages were found in rural (63.67) and refugee camp (62.9) than in urban children (52.6). Of all localities, school children with light spore load comprised the highest percentage of the children examined (37.4), followed by moderate (6.13), and heavy (0.41) spore load categories. However, children with undetected spore load comprised 36.05% of all children. Spore load distribution did not show clear seasonal variations in the study period. Higher percentages of moderate and heavy spore loads were found in male children (8.72 and 0.69, respectively) than in female children (3.4 and 0.1, respectively). However, higher percentages of undetected (38.3) or light spore loads (58.4) were found in females than in males (34.04 and 56.53, respectively). This revised version was published online in June 2006 with corrections to the Cover Date.     

Principal and intercalated cells in primary cultures of rabbit renal collecting tubules revealed by monoclonal antibodies.

In this study we describe the production and characterization of two monoclonal antibodies (mAb 503 and mAb 703) raised against the apical membrane of rabbit cortical collecting tubule (CCT) cells. The specificity of the two monoclonal antibodies was studied by immunoelectron microscopy on kidney sections. These antibodies were used to identify principal and intercalated cells in primary cultures of CCT. To assess the maintenance of the basic characteristics of the cortical collecting cells during the growth process we determined the biochemical and electrophysiological properties of cultured CCT. Of the monoclonal antibodies produced mAb 503 was specifically directed against the luminal membrane of intercalated cells as shown by immunoelectron microscopy. mAb 703 bound specifically the apical membrane of the principal cells. In primary cultures of CCT mAb 503 and mAb 703 bound antigens present on the apical membrane of different cells and permitted the study of the distribution of the two cell types. Results showed the maintenance of the epithelial polarity of cultured CCT and the expression of specific antigens.     

Distribution,occurrence and characterization of entomopathogenic fungi in agricultural soil in the Palestinian area

The occurrence of entomopathogenic fungi was investigated in irrigated vegetable fields and citrus orchards soils, over a nine-month period (April-December 1999), using the Galleria bait method (GBM). Entomopathogenic fungi were found to occur in 33.6% of the soil samples studied, with positive samples yielding 70 fungal isolates, belonging to 20 species from 13 genera. Conidiobolus coronatus was the most frequent and abundant entomopathogenic species recovered, comprising 31.4% of the total number of isolates. Soil pH, soil moisture content and the geographical location had minor or no effect on the isolation of entomopathogenic fungi in the fields studied. On the other hand, organic matter content of soil, and vegetation type were found to significantly affect the occurrence of entomopathogenic fungi in soil habitats, with orchard fields yielding larger numbers of isolates than vegetable fields. Using Koch's postulates the pathogenicity of fungal isolates to Galleria larvae was found to range from 16-100% (mortality rate). Isolates of C. coronatus proved to be the most virulent isolates recovered. The effect of media and temperature on mycelial growth rate, conidial production and conidial germination of six entomopathogenic fungal species (C. coronatus, Entomophaga grylli, Erynia castrans, Hirsutella jonesii, Paecilomyces farinosus and Sporodiniella umbellata) was also studied. Mycelial growth rate, spore production and spore germination were significantly affected by media, temperature and isolates. In view of the present results, C. coronatus appears to be a good candidate for pest control in agricultural soils, as it has a wide tolerance to agricultural practices, has frequently been isolated from both vegetable and orchard fields, and is characterized by high mycelial growth rate, conidial production and conidial germination.     

Ecology of cycloheximide-resistant fungi in field soils receiving raw city wastewater or normal irrigation water

The effect of raw city wastewater irrigation on biodiversity and population densities of a cycloheximide-resistant (CH) fungal community was studied in 13 field soils receiving either raw city wastewater or normal irrigation, and in raw city wastewater in the Nablus area, using the hair baiting technique (HBT) and a surface soil dilution plating (SSDP) technique. Three of these fields [one had been receiving raw city wastewater for more than ten years and was designated a heavily polluted field, and the other 2 were cultivated for the first time and were either irrigated with raw city wastewater (newly polluted field) or normal irrigation water (nonpolluted)], were sampled 4–7 times over a 9-month period. The other ten fields, which had been under raw city wastewater irrigation for more than 10 years, were sampled only once. Fifty-seven CH-resistant species belonging to 18 genera were recovered, of which 49 species were recovered from soil habitats and 28 species from raw city wastewater. The HBT had shown to be more efficient in the isolation of pathogenic and potentially pathogenic fungi including dermatophytes. A higher percentage of this group of fungi was recovered from the three main field soils studied using HBT (70% of all isolates), than the SSDP (35.5%); no dermatophytes were recovered by the SSDP method. Two dermatophytes (Microsporum gypseum, and Trichophyton ajelloi), and five more fungi (Arthroderma cuniculi, A. curreyi, Chrysosporium keratinophilum, C. tropicum, and C. pannorum), were recovered from these habitats. Wastewater irrigation seemed to have affected the fungal population densities, with the highest population densities being found in the heavily polluted field soil, while lower population densities were found in the nonpolluted field soil. Increases in organic matter were also observed as a result of sewage effluent irrigation. However, basic similarities in the biodiversity of CH-resistant fungal communities existed in nonpolluted and polluted field soils, and raw city wastewater. Comparable numbers of fungal species were recovered from the three main field soils. The species most commonly found in those habitats included: Alternaria alternata, Aspergillus candidus, Geotrichum candidum, and Paecilomyces lilacinus. Field soils receiving either raw city wastewater or normal irrigation water, were found to be rich in pathogenic and potentially pathogenic CH-resistant fungi, including dermatophytes, with raw city wastewater yielding the highest percentage (81%), followed by the newly wastewater irrigated field (77.7%), the nonpolluted field (67%), and the heavily polluted field (63.4%). Hygienic measures should therefore be taken to control the spread of these fungi in the environment of human communities, and to avoid mycotic infections among farmers. This revised version was published online in August 2006 with corrections to the Cover Date.