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1.
Water extracts of thermal and acoustic fiberglass insulations used in the duct work of heating, ventilation and air conditioning (HVAC) systems supported germination of conidia and growth of Aspergillus versicolor (Vuillemin) Tiraboschi 1908–9 and Aspergillus fumigatus Fresenius 1863. Urea, formaldehyde and unidentified organics were detected in the extracts. Formaldehyde in concentrations similar to those found in the extracts restricted the growth of both species in enriched media. A. versicolor, the more common species associated with fiberglass insulations, was more resistant to formaldehyde than A. fumigatus. 相似文献
2.
Fiberglass duct liners and fiberglass duct boards from eight buildings whose occupants complained of unacceptable or moldy odors in the air were found to be heavily colonized by fungi, particularly by Aspergillus versicolor. Unused fiberglass was found to be susceptible to fungal colonization in environmental chambers dependent upon relative humidity. No colonization was observed at relative humidities below 50%. 相似文献
3.
Summary Evans' tube and cellophane agar-disc techniques were used to evaluate the colonization capacity of the soil microbes and fungistasis,
respectively. Spore germination of Alternaria tenuis, Curvularia geniculata, Helminthosporium rostratum and Pestalotia sp. was studied on a natural soil.
Aspergillus fumigatus was the pioneer colonizer, followed in the order of decreasing colonizing capacity by, A. flavus, A. niger, A. terreus and Penicillium nigricans. Sensitivity of test spores to soil fungistasis declined in the order, C. geniculata → Pestalotia sp. → A. tenuis → H. rostratum. The fungistatic level of the soil samples decreased gradually from side arms 1 to 7 of the Evans tube, inoculated with unsterilized
soil from one end.
Studies conducted with an inoculum of four soil fungi ( A. fumigatus, A. flavus, A. niger, and P. nigricans) as well as those involving fumigation of Evans tube by CS 2 also proved the greater colonizing capacity of A. fumigatus. The level of fungistasis followed closely the colonization pattern of this fungus. When added individually to the soil,
all fungi were able to inhibit spore germination of test fungi to some degree or other. 相似文献
4.
Soil samples from an agricultural field contaminated with 10 ppm 14C-benz( a)anthracene in glass tubes were brought into contact with cultures of wood-rotting fungi, precultivated on wheat straw substrate.
Forty-five strains of white-rot fungi and four brown-rot fungi were tested for their ability to colonize the soil and to mineralize 14C-benz( a)anthracene to 14CO 2 within a 20-week incubation time. Twenty-two white-rot fungi and all brown-rot fungi were unable to colonize the soil. Twenty-three
strains of white-rot fungi, all belonging to the genus Pleurotus, colonized the soil. During the experiment the noncolonizing fungi and their substrate disintegrated more and more to a nonstructured
pulp from which water diffused into the soil. The same phenomenon was observed in the control which contained only straw without
fungus and contaminated soil. In samples with colonizing fungi the substrate as well as the mycelia in the soil remained visibly
unchanged during the entire experiment. Surprisingly, most samples with fungi not colonizing the soil and the control without
fungus liberated between 40 and 58 % of the applied radioactivity as 14CO 2 whereas the samples with the colonizing fungi respired only 15–25 % as 14CO 2. This was 3–5 times more 14CO 2 than that liberated from the control (4.9 %) which contained only contaminated soil without straw and fungus. A similar result
was obtained with selected colonizing and noncolonizing fungi and soil contaminated with 10 ppm 14C-pyrene. However, in pure culture studies in which 14C-pyrene was added to the straw substrate, Pleurotus sp. (P2), as a representative of the colonizing fungi, mineralized 40.3 % of the added radioactivity to 14CO 2. The noncolonizing fungi Dichomitus squalens and Flammulina velutipes liberated only 17.2 or 1.7 %, respectively, as 14CO 2. These results lead to the hypothesis that the native soil microflora stimulated by the formed products of straw lysis is
responsible for high degradation rates found with noncolonizing fungi. 相似文献
5.
A study was conducted for isolation, identification and antibacterial potential of fungal endophytes of Adenocalymma alliaceum Miers., (Bignoniaceae), a medicinal shrub vine plant which has long history for its usages in curing various disorders. A
total of 149 isolates of endophytic fungi representing 17 fungal taxa were obtained from 270 segments (90 from each stem,
leaf and petiole) of this plant. Hyphomycetes (77.85%) were the most prevalent, followed by Ascomycetes (8.05%) and Coelomycetes
(4.03%) respectively. A considerable amount of fungal isolates was kept under (10.07%) Mycelia-Sterilia (MS). Leaf harboured
maximum colonization of endophytic fungi (72.22%) which was greater than stem (67.78%) and petiole (25.54%). The Jc similarity
index was maximum (0.619) between stem vs leaf followed by leaf vs petiole (0.571) and stem vs petiole (0.428). The dominant
endophytic fungi were Alternaria alternata, Aspergillus niger, Stenella agalis, Fusarium oxysporum, Curvularia lunata and Fusarium roseum. Among twelve endophytic fungi tested for antibacterial activity, crude extracts of nine endophytic fungi (75%), showed antibacterial
potential against one or more clinical human pathogens. Alternaria alternata, Curvularia lunata, Penicillium sp. and Chaetomium globosum exhibited significant antibacterial activity against 4 of 5 tested pathogens, showing broad spectrum activity. This investigation
explains the value of sampling from different tissues of a host plant for the greater species diversity, and additionally,
the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for
many of the useful antibacterial compounds. 相似文献
6.
Fungal endophytes were isolated from twigs of Juniperus procera (Cupressaceae) collected from Taif region (Saudi Arabia). Twenty-six different taxa were recovered. The overall foliar colonization rate was 36%. A total of 144 isolates were obtained and identified into six distinct operational taxonomic units based on the sequencing of the internal transcribed spacer regions of the rRNA gene. The most prevalent fungi were Aspergillus fumigatus, Penicillium oxalicum, Preussia sp., Peyronellaea eucalyptica, Peyronellaea sancta and Alternaria tenuissima. A total of 144 isolates were tested for antibacterial and antifungal activities against Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans and Fusarium solani in which 52 isolates showed antimicrobial activity against at least one of the tested microbes. Aspergillus fumigatus (7 isolates), Hypocrea lutea (4), Penicillium oxalicum (10) and Preussia sp. (5) presented the strongest antimicrobial activity. This study confirmed the variation of different isolates of the same species in terms of antibacterial activity. Also, it indicated that the endophytic fungi of Juniperus procera plants should be another potential source of bioactive antimicrobial agents. 相似文献
7.
Four fungal species including two dermatophytes and two saprophytes were isolated from sewage sludge samples at Basrah (Iraq)
they were tested for their degradative ability towards three types of keratin substrates (human hair, chicken feathers and
wool). The rate of keratin degradation was expressed as weight loss over three weeks of incubation using a liquid culture
medium. Human hair had the highest degradation rate by colonization of Chrysosporium pannicola and Microsporum gypseum at a rate of 62% and 4% respectively. Chicken feathers were highly degraded by Aspergillus flavus (32%) while wool degradation was highest by C. pannicola (45.5%) and Trichophyton mentagrophytes var. erinacei (38%). There was a significant difference (p < 0.00l) in keratin substrate degradation rates by the examined fungi. Keratinase
activity was highest for C. pannicola and M. gypseum in the culture medium baited with human hair. Aspergillus flavus revealed the highest activity of this enzyme in cultures amended with chicken feathers while T. mentagrophytes var. erinacei showed highest keratinase activity in cultures with wool substrate. The amount of protein released into the culture medium
varied among the tested fungi. The medium's alkalinity increased over incubation time from 6.5 to 7.8. Microscopic examination
showed maceration of the keratin substrates by the fungi.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
Fungal endophytes were isolated from the leaves of Calotropis procera (Apocynaceae) collected from Taif region (Saudi Arabia). Thirty-three different taxa were recovered. The overall foliar colonization rate was 35.1%. A total of 161 isolates were obtained and identified into 33 distinct operational taxonomic units based on the sequencing of the internal transcribed spacer regions of the rRNA gene. The most prevalent fungi were Aspergillus flavus, Chaetomium globosum, Cochliobolus lunatus, Fusarium dimerum, F. oxysporum, and Penicillium chrysogenum. A total of 161 isolates were tested for antifungal activities against four plant pathogenic fungi ( Alternaria alternata, Fusarium oxysporum, Botrytis cinerea, and Pythium ultimum), of which 33 isolates showed antifungal activity against at least one plant pathogenic fungi. Four isolates of Chaetomium globosum and three isolates of Myrothecium verrucaria showed the strongest antifungal activity. This study reported the occurrence of a much wider spectrum of fungi, when compared with previous work. Also, it confirmed the variation of different isolates from the same species in terms of antifungal activity. 相似文献
10.
Complaints characteristic of those for sick building syndrome prompted mycological investigations of a modern multi-story office building on the Gulf coast in the Southeastern United States (Houston-Galveston area). The air handling units and fiberglass duct liner of the heating, ventilating and air conditioning system of the building, without a history of catastrophic or chronic water damage, demonstrated extensive colonization with Penicillium spp and Cladosporium herbarum. Although dense fungal growth was observed on surfaces within the heating-cooling system, most air samples yielded fewer than 200 CFU m –3. Several volatile compounds found in the building air were released also from colonized fiberglass. Removal of colonized insulation from the floor receiving the majority of complaints of mouldy air and continuous operation of the units supplying this floor resulted in a reduction in the number of complaints. 相似文献
11.
Summary In a continuing search for field sources of endomycorrhizal fungi that tolerate high levels of available phosphorus in soil, samples were obtained from long-established liberally fertilized hops ( Humulus lupulus L.) and peppermint ( Mentha piperita L.) fields. In hops fields, where extractable P (Bray) levels ranged from 21–196 ppm, spores of two Acaulospora spp. and six Glomus spp. were isolated. From peppermint fields with P levels of 44 to 244 ppm, spores of one Acaulospora sp., four Glomus spp. and one Gigaspora sp. were obtained. Vesicular-arbuscular mycorrhizal (VAM) fungi were found colonizing most roots to some extent, despite the very high fertility of several sites. Although percentages of colonization in hops tended to be low, ranging from 0 to 9.3%, colonizations in peppermint roots were considerably higher averaging 26.5% between the sampled fields, notwithstanding P levels as high as 244 ppm. Curiously, considerable external VAM hyphae were found adherent to or entangling roots in many cases, even where percentage of root length with internal VAM structures was low. The functional benefit, neutrality, or detriment to plants of such high-P tolerant species remains to be determined.Contribution from the USDA-ARS, Horticultural Crops Research Laboratory and the Dept. of Soil Science, Oregon State University, in cooperation with the Oregon State University Agricultural Experiment Station, Corvallis, OR 97331. Technical paper no. 6979 of the latter 相似文献
12.
California exports tree nuts to countries where they face stringent standards for aflatoxin contamination. Trade concerns
have stimulated efforts to eliminate aflatoxins and Aspergillus flavus from almonds, pistachios and walnuts. Incidence of fungi on tree nuts and associations among fungi on tree nuts were studied.
Eleven hundred pistachios, almonds, walnuts and brazil nuts without visible insect damage were plated on salt agar and observed
for growth of fungi. Samples came both from California nut orchards and from supermarkets. To distinguish internal fungal
colonization of nuts from superficial colonization, half the nuts were surface-sterilized before plating. The most common
genera found were Aspergillus , Rhizopus and Penicillium . Each species of nut had a distinct mycoflora. Populations of most fungi were reduced by surface sterilization in all except
brazil nuts, suggesting that they were present as superficial inoculum on (rather than in) the nuts. In general, strongly
positive associations were observed among species of Aspergillus ; nuts infected by one species were likely to be colonized by other species as well. Presence of Penicillium was negatively associated with A. niger and Rhizopus in some cases. Results suggest that harvest or postharvest handling has a major influence on nut mycoflora, and that nuts
with fungi are usually colonized by several fungi rather than by single species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
Arbuscular mycorrhizal (AM) fungi can form symbiosis with 90% of the vascular plants and play important roles in ecosystem. To realize the AM fungal colonization at different succession stages in saline-alkali land and screen AM fungi species with great functions, roots and soil samples were collected from the three succession stages of Songnen saline-alkali grassland. The soil properties and AM fungal colonization were measured, and the fungus distributed extensively in three stages was annotated by sequencing for AML1/AML2 target, subsequently, maize was selected as the host to verify its colonization. The results showed that the soil properties improved with the succession of saline-alkali grassland. The plants’ communities of the three stages could be colonized by AM fungi, and the colonization rate of Leymus chinensis (the third stage) ranged from 66.67% to 100%, Puccinellia tenuiflora (the second stage) ranged from 50% to 80%, while the Suaeda glauca (the first stage) was only 35%–60%. Glomeraceae sp1 was identified as the dominant AM fungi species which occurred frequently in the succession of saline-alkali land with the isolation frequency, relative abundance, and importance value of 100%, 18.1%, and 59.1%, respectively. The colonization rate of Glomeraceae sp1 in maize ranged from 80% to 87% and similar mycorrhizal characteristics were detected in the roots of P. tenuiflora, S. glauca, and L. chinensis, indicating that Glomeraceae sp1 colonized the samples in the field. The correlation matrix indicated that colonization rate, colonization intensity, and vesicle abundance were closely related to soil conditions most, and they were related significantly to all the soil properties except cellulase activity. Besides, redundancy analysis (RDA) showed that soil properties drove the changes of AM fungal colonization and sporulation. These results will provide theoretical support for realizing the relationship between AM fungal colonization and soil conditions, and also for the exploration of AM fungi species with great functions. 相似文献
14.
Current recommendations for remediation of fiberglass duct materials contaminated with fungi specify complete removal, which
can be extremely expensive, but in-place duct cleaning may not provide adequate protection from regrowth of fungal contamination.
Therefore, a common practice in the duct-cleaning industry is the postcleaning use of antifungal surface coatings with the
implication that they may contain or limit regrowth. However, even the proper use of these products has generally been discouraged
because little research has been conducted on the effectiveness of most products as used in heating, ventilating, and air-conditioning
(HVAC) systems. Three different coatings were evaluated on fiberglass duct liner (FGDL). Two of the three coatings were able
to limit growth in the 3-month study; the third did not. One of the coatings that was able to limit growth was further evaluated
in a comparison of FGDL or galvanized steel (GS) under conditions that mimicked their use in HVAC systems. The results showed
that both moderately soiled and heavily soiled uncoated FGDL and GS duct material can support fungal growth, but that GS duct
material was more readily cleaned. The use of an antifungal coating helped limit, but did not fully contain, regrowth on FGDL.
No regrowth was detected on the coated GS. Journal of Industrial Microbiology & Biotechnology (2002) 29, 38–43 doi:10.1038/sj.jim.7000261
Received 19 November 2001/ Accepted in revised form 29 March 2002 相似文献
15.
Arbuscular mycorrhizae, ubiquitous mutualistic symbioses between plant roots and fungi in the order Glomales, are believed to be important controllers of plant responses to global change, in particular to elevated atmospheric CO 2. In order to test if any effects on the symbiosis can persist after long-term treatment, we examined root colonization by arbuscular mycorrhizal (AM) and other fungi of several plant species from two grassland communities after continuous exposure to elevated atmospheric CO 2 for six growing seasons in the field. For plant species from both a sandstone and a serpentine annual grassland there was evidence for changes in fungal root colonization, with changes occurring as a function of plant host species. We documented decreases in percentage nonmycorrhizal fungal root colonization in elevated CO 2 for several plant species. Total AM root colonization (%) only increased significantly for one out of the five plant species in each grassland. However, when dividing AM fungal hyphae into two groups of hyphae (fine endophyte and coarse endophyte), we could document significant responses of AM fungi that were hidden when only total percentage colonization was measured. We also documented changes in elevated CO 2 in the percentage of root colonized by both AM hyphal types simultaneously. Our results demonstrate that changes in fungal root colonization can occur after long-term CO 2 enrichment, and that the level of resolution of the study of AM fungal responses may have to be increased to uncover significant changes to the CO 2 treatment. This study is also one of the first to document compositional changes in the AM fungi colonizing roots of plants grown in elevated CO 2. Although it is difficult to relate the structural data directly to functional changes, possible implications of the observed changes for plant communities are discussed. 相似文献
16.
A systematic study was made of the endophytes of Azadirachta indica A. Juss (the neem tree) growing in several of its natural habitats in India. A total of 233 isolates of endophytic fungi
representing 18 fungal taxa were obtained from segments of bark, stem, and leaves of this tree. Hyphomycetes (62.2%) were
the most prevalent followed by the Coelomycetes (27.4%) and Mycelia Sterilia (7.7%). As mathematically determined, the maximum
species richness and frequency of colonization of endophytes appeared in leaf segments rather than stem and bark tissues from
each location. Endophytic colonization frequency was also greater in leaves (45.5%) than bark (31.5%). The leaf samples from
all locations were nearly constant in their endophytic composition, whereas bark samples showed maximum diversity at different
locations. Inter-site comparisons for endophytic diversity, however, were not significantly different with Loc1 and Loc2 having
a maximum of 66.67% J
c. The smallest similarity was between Loc2 and Loc3 of 54.17% J
c. The dominant endophytic fungi isolated were Phomopsis oblonga, Cladosporium cladosporioides, Pestalotiopsis sp., Trichoderma sp, and Aspergillus sp. Genera such as Periconia, Stenella, and Drechslera are reported here for the first time as endophytes from this host plant. This report illustrates the value of sampling different
tissues of a given plant in several locations to obtain the greatest species diversity of endophytes. The rich and sizeable
collection of endophytic fungi from this specific plant may represent a unique source of one or more of the interesting and
useful bioactive compounds normally associated with A. indica such as the azadirachtins and related tetranortriterpenoids. 相似文献
17.
The present study was carried out to investigate the higher fungi colonizing the herbaceous mangrove associate Acanthus ilicifolius. This paper reports part of an investigation to determine if there is vertical distribution of fungi on the standing plant.The Mai Po Mangrove, Hong Kong is estuarine with great variations in salinity mainly due to the influence of the Pearl River. Senescent and dead stems of standing Acanthus ilicifolius were collected from mangroves in Mai Po from April to December 1992. The maximum tidal range observed was 2.6 m. A stratified sampling strategy was employed to assess the vertical distribution on the standing plant. A total of 44 fungi were collected: 32 Deuteromycotina, 11 Ascomycotina and 1 Basidiomycotina. Very frequent species were Acremonium sp.(55%), Colletotrichum gloesporioides cf.(42.5%), Phoma sp. (42.5%) Fusarium sp.,(25%), Tubercularia sp. (24.2%) and Phialophora sp. cf. (19.2%). Agerita sp., Corynespora cassiicola, Stachybotrys chartarum, Trichoderma sp. and D82 were frequent, while the remaining species were recorded at less than 10%. Vertical zonation of fungi colonizing the standing stems was observed. The apical portions were colonized by typical terrestrial fungi and the basal portions by marine species. This can be attributed to both the nature of the substratum and the degree of exposure due to tidal inundation. 相似文献
18.
A membrane-screening method was developed in conjunction with flow cytometric (FC) analysis for determining the efficacies
of antimould pressure-treatment formulations for mould species of cosmetic significance on southern pine. Fusarium subglutinans, Aspergillus flavus, Penicillium chrysogenum, and Paecilomyces spp. were the predominant moulds colonizing surfaces of the variously treated pine stored in sealed plastic bags over 3-
to 6-month periods. Nylon membranes placed directly on pressure-treated pine and membranes saturated with the various formulations
were inoculated with the conidia of selected moulds. FC analysis of conidia stained with propidium iodide (PI) before and
after exposure to the pressure-treatment formulations permitted a rapid assessment of the inocula and selection of those pressure-treatment
formulations with probable inhibitory activity versus probable nonactive preparations. Recoveries of the fungi from the membranes
over 9–14 days were in general agreement with the emergence of colonizing fungi on the similarly preserved uninoculated pine
stored in sealed plastic bags for 6 months. This combination of procedures provided for a relatively rapid assessment of preservative
formulations designed to provide enhanced efficacy against surface mould growth on lumber during storage and retail display.
Received 21 December 2001/ Accepted in revised form 20 May 2002 相似文献
19.
The survival and development of two inoculant ectomycorrhizal fungi ( Hebeloma westraliense Bough. Tom. and Mal. and Setchelliogaster sp. nov.) on roots of outplanted Eucalyptus globulus Labill. was examined at two expasture field sites in the south-west of Western Australia. Site 1 was a gravelly yellow duplex soil, and Site 2 was a yellow sandy earth. Plants were grown in steamed or unsteamed soil, in root bags designed as field containers for young growing trees. Three, 6 and 12 months after outplanting, plants were removed from these bags and assessed for dry weights of shoots and ectomycorrhizal colonization of roots.The inoculant ectomycorrhizal fungi (identified on the basis of the colour and morphology of their mycorrhizas) survived on roots of E. globulus for at least 12 months after outplanting at both field sites. At Site 1, however, colonization of new fine roots by the inoculant fungi was low (less than 20% of fine root length). Inoculation had no effect on the growth of E. globulus at this site. In contrast, at Site 2 the inoculant ectomycorrhizal fungi colonized up to 30–50% of new fine root length during the first 6 months after outplanting. There was a corresponding growth response to ectomycorrhizal inoculation at this site, with a close relationship (r 2=0.82 **) between plant growth at 12 months and root colonization at 3 months. Plant growth at 12 months was related less closely with root colonization at 6 or 12 months. Root colonization by resident ectomycorrhizal fungi increased with time at both field sites. At Site 2, this increase appeared to be at the expense of colonization by the inoculant fungi, which was reduced to less than 10% of fine root length at 12 months. Steaming the soil had little effect on colonization by the inoculant ectomycorrhizal fungi at either field site, but decreased colonization by the resident ectomycorrhizal fungi. 相似文献
20.
The growth of six strains of yeast was analyzed in vitro in order to assess their capacity for colonizing (adhesion and invasion) hydrophilic contact lenses. Lenses with different water content were cultured in two culture media for 3, 7, 14, and 21 days. Only strain 93150 of Candida albicans could adhere to and invade the polymers. Specifically, fungal growth was observed in cultures with Sabourauds broth. The degree of yeast colonization of contact lenses was significantly related to the species, the strain, and the culture medium in which the yeast and lenses were cultured. The results here obtained were compared with those reported for the filamentous fungus Aspergillus niger 2700. For both microorganisms, the strain and the medium in which the lenses and microorganism were cultured influenced the colonization, but the percentage of colonized lenses, the degree of colonization, and the density and size of the internalized colonies were always noticeably lower for C. albicans 93150. Colonization by A. niger 2700 was also related to the type of material of the lenses and the incubation period. For both microorganisms, when the strain is right and the growth and development are correct, colonization of hydrophilic contact lenses occurs. 相似文献
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