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Discovering Metal-Tolerant Endophytic Fungi from the Phytoremediator Plant Phragmites
2018
Sim, CarrieSiew Fang | Cheow, YuenLin | Ng, SiLing | Ting, AdelineSu Yien
Fifteen endophytic isolates were recovered from the phytoremediator plant Phragmites. Phylogenetic analysis revealed they were primarily from the class Sordariomycetes and Dothiodiomycetes. Most of the endophytes in Sordariomycetes were from the orders Diaporthales (six isolates, e.g., Diaporthe, Phomopsis), Hypocreales (two isolates, e.g., Gliomastix, Trichoderma), and Xylariales (one isolate, e.g., Arthrinium), while members from Dothideomycetes were from the order Pleosporales (six isolates, e.g., Bipolaris, Curvularia, Microsphaeropsis, Saccharicola). The endophytes demonstrated varying responses to the metals (Al³⁺, Cu²⁺, Zn²⁺, Pb²⁺, and Cd²⁺) and concentrations (10, 25, 50, 100, and 200 mg L⁻¹) tested, with isolates of Dothideomycetes predominantly more tolerable to metals (80–97% tolerance) than Sordariomycetes (73–90% tolerance). Pb²⁺ was the least harmful towards the endophytes, while Al³⁺ appeared to be highly toxic with mean tolerable range (TR) of > 200 and 25–50 mg L⁻¹, respectively. Endophytes thriving in toxic metals may further be applied for biocontrol, bioremediation, or growth-promoting purposes in metal-contaminated areas.
Afficher plus [+] Moins [-]Fungal populations in the bedroom dust of children in Havana, Cuba, and its relationship with environmental conditions
2021
Sánchez Espinosa, Kenia C. | Rojas Flores, Teresa I. | Davydenko, Sonia Rodríguez | Venero Fernández, Silvia J. | Almaguer, Michel
The study of the fungal community composition in house dust is useful to assess the accumulative exposure to fungi in indoor environments. The objective of this research was to characterize the fungal diversity of house dust and its association with the environmental conditions of bedrooms. For this, the dust was collected from 41 bedrooms of children between the ages of 8 and 9 with a family history of asthma, residents of Havana, Cuba. The fungal content of each sample was determined by two methods: plate culture with malt extract agar and by direct microscopy. An ecological analysis was carried out from the fungal diversity detected. To describe the factors associated with the fungi detected, bivariate logistic regression was used. Through direct microscopy, between 10 and 2311 fragments of hyphae and spores corresponding mainly to Cladosporium, Coprinus, Curvularia, Aspergillus/Penicillium, Xylariaceae, and Periconia were identified. Through the culture, 0–208 CFU were quantified, where Aspergillus, Cladosporium, and Penicillium predominated. The culturability evidenced the differences between the quantification determined by both methods. A positive relationship was found between the type of cleaning of the furniture, the presence of trees in front of the bedroom, indoor relative humidity, indoor temperature, the presence of air conditioning, and natural ventilation with specific spore types and genera. The use of two different identification methods allowed to detect a greater fungal diversity in the residences evaluated. Monitoring the exposure to these fungal allergens in childhood can help to prevent sensitization in the allergic child, the development of asthma, and other respiratory diseases.
Afficher plus [+] Moins [-]Are mosque carpets’ reservoirs for fungi causing superficial foot mycosis? A cross-sectional study in Riyadh, Saudi Arabia
2020
Alsaif, Fahad | Somily, Ali | Balbeesi, Amal | Alhammad, Ghadah | Almutawa, Afnan | Altawil, Lama
The possibility of superficial foot mycoses to spread through contaminated mosque carpets between worshipers imposes a great health burden and is never addressed in Riyadh, SA. We aimed to assess the prevalence of fungal infections, especially human dermatophytosis acquired from mosque carpets, in five different regions of Riyadh, Saudi Arabia and establish a means of contamination control. A cross-sectional study of 100 mosques in Riyadh, Saudi Arabia, was conducted, using a multistage random cluster sampling technique. The study included mosques that had an ablution area and regularly hosted five prayers a day. Sterile swabs were used for sampling, and the samples were transported to the laboratory for culture and analysis using a micro-scan system. A total of 199 (65%) samples contained several fungal species. Rhodotorula (74%), Cladosporium (47%), Bipolaris (46.6%), other yeasts (43.7%), Alternaria (40%), dematiaceous molds (34%), Curvularia (32.4%), and Candida (31%) were the most frequently isolated species. Species belonging to several other genera were also detected. This study revealed a relatively high prevalence of fungal organisms in mosque carpets in Riyadh, suggesting the need for implementing new strategies and laws to increase the level of hygiene awareness among worshipers and mosque caretakers to limit the spread of foot fungal infections.
Afficher plus [+] Moins [-]Biodecolorization of recalcitrant dye as the sole sourceof nutrition using Curvularia clavata NZ2 and decolorization ability of its crude enzymes
2015
Neoh, Chin Hong | Lam, Chi Yong | Lim, Chi Kim | Yahya, Adibah | Bay, Hui Han | Ibrahim, Zaharah | Noor, Zainura Zainon
Extensive use of recalcitrant azo dyes in textile and paper industries poses a direct threat to the environment due to the carcinogenicity of their degradation products. The aim of this study was to investigate the efficiency of Curvularia clavata NZ2 in decolorization of azo dyes. The ability of the fungus to decolorize azo dyes can be evaluated as an important outcome as existing effluent treatment is unable to remove the dyes effectively. C. clavata has the ability to decolorize Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Congo Red azo dyes, utilizing these as sole sources of carbon and nitrogen. Ultraviolet–visible (UV–vis) spectroscopy and Fourier infrared spectroscopy (FTIR) analysis of the extracted RB5’s metabolites along with desorption tests confirmed that the decolorization process occurred due to degradation and not merely by adsorption. Enzyme activities of extracellular enzymes such as carboxymethylcellulase (CMCase), xylanase, laccase, and manganese peroxidase (MnP) were also detected during the decolorization process. Toxicity expressed as inhibition of germination was reduced significantly in fungal-treated azo dye solution when compared with the control. The cultivation of C. clavata under sequential batch system also recorded a decolorization efficiency of above 90 %. The crude enzyme secreted by C. clavata also showed excellent ability to decolorize RB5 solutions with concentrations of 100 ppm (88–92 %) and 1000 ppm (70–77 %) without redox mediator. This proved that extracellular enzymes produced by C. clavata played a major role in decolorization of RB5.
Afficher plus [+] Moins [-]Decolorization of palm oil mill effluent using growing cultures of Curvularia clavata
2014
Neoh, Chin Hong | Lam, Chi Yong | Lim, Chi Kim | Yahya, Adibah | Ibrahim, Zaharah
Agricultural wastewater that produces color are of environmental and health concern as colored effluent can produce toxic and carcinogenic by-products. From this study, batch culture optimization using response surface methods indicated that the fungus isolated from the pineapple solid waste, Curvularia clavata was able to decolorize sterile palm oil mill effluent (POME) which is mainly associated with polyphenol and lignin. Results showed successful decolorization of POME up to 80 % (initial ADMI [American Dye Manufacturing Index] of 3,793) with 54 % contributed by biosorption and 46 % by biodegradation after 5 days of treatment. Analysis using HPLC and GC-MS showed the degradation of color causing compound such as 3-methoxyphenyl isothiocynate and the production of new metabolites. Ecotoxicity test indicated that the decolorized effluent is safe for discharge. To determine the longevity of the fungus for a prolonged decolorization period, sequential batch decolorization studies were carried out. The results showed that lignin peroxidase and laccase were the main ligninolytic enzymes involved in the degradation of color. Carboxymethyl cellulase (CMCase) and xylanase activities were also detected suggesting possible roles of the enzymes in promoting growth of the fungus which consequently contributed to improved decolorization of POME. In conclusion, the ability of C. clavata in treating color of POME indicated that C. clavata is of potential use for decolorization and degradation of agricultural wastewater containing polyphenolic compounds.
Afficher plus [+] Moins [-]A preliminary report of indigenous fungal isolates from contaminated municipal solid waste site in India
2017
Awasthi, Abhishek Kumar | Pandey, Akhilesh Kumar | Khan, Jamaluddin
Municipal solid waste (MSW) containing harmful substances is a major concern in waste management and can cause adverse effects on diversity of fungi in soil. The main objective was to evaluate the fungal diversity inhabiting in the soil nearby MSW disposal site. The fungal strains were isolated in potato dextrose agar (PDA), media at temperatures 28 ± 1 °C by using standard serial dilution pour plate method, and appeared fungal colonies identified based on morphological characteristics. The overall most fungal diversity was found in soil sample collected from S5, followed by S4, S3, S1, and least in S2 site. A total of 24 fungal isolates recovered from the different MSW sites and Aspergillus sp., Fusarium sp., and Curvularia sp. genus has isolated from all the samples. In addition, the metal tolerance index performed because it needs to classify the fungus for their best use as potential agent for environmental protection. The metal tolerance outcomes revealed that both metals (cadmium and chromium) has appeared as the highest growth inhibitor for most strains and even fungal colonies did not propagate very well on the surface of media. Therefore, these findings suggest that the pre-adapted indigenous fungal isolates have proven remarkable tolerance ability to both metals. Furthermore, these highly metal-tolerant fungal strains are recommended for detail research or can use in pilot-scale bioremediation application to treat contaminated site.
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