RESUMEN
Vicia faba (faba bean) is one of the most significant leguminous crops. The faba bean is specialized by maximum nutritional value, in energy and protein content, which leads it to be suitable for food and feed production. Diseases caused with fungi are amongst the biotic factors responsible for decreasing in faba bean yields. In this work, Cladosporium isolates were recorded in cultivated faba bean leaves and pods collected from markets in Qena, Upper Egypt; morphological features and molecular characterization based on actin gene were performed. The ability of the pathogens to cause disease in faba bean seedlings and the biocontrol method to avoid the pathogenic effect of Cladosporium were determined. Results showed that Cladosporium is the main genera isolated from faba beans, and the morphological criteria showed presence of three species complex groups of Cladosporium (C. cladosporioides, C. herbarum and C. sphaerospermum) and the confirmation with molecular characterization revealed the existence of four species in the three groups. All the 26 tested strains of Cladosporium were able to cause leaf lesions on Vicia faba seedlings with different levels. Chaetomium globosum is a biocontrol agent could inhibit the growth of the majority strains of Cladosporium.
Asunto(s)
Cladosporium/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Vicia faba/microbiología , Agentes de Control Biológico/metabolismo , Chaetomium/crecimiento & desarrollo , Chaetomium/aislamiento & purificación , Cladosporium/genética , Cladosporium/aislamiento & purificación , Filogenia , Plantones/microbiologíaRESUMEN
AIMS: Compare and characterize Chaetomium strains with special regard to their potentialities as biocontrol agents. METHODS AND RESULTS: Twelve strains of the fungal genus Chaetomium from diverse ecological niches were identified as belonging to six different species. Large differences were observed between the strains with regard to temperature requirements for mycelial growth and pigmentation of culture filtrates. Culture filtrates and ethyl acetate extracts were assayed for fungicidal effects against important phytopathogens both on agar media and in multiwell plates. The samples from Chaetomium globosum were particularly active against Botrytis cinerea, Pyrenophora graminea and Bipolaris sorokiniana, while those from C. cochliodes and C. aureum were inhibitory towards Phytophthora infestans, and P. infestans and Fusarium culmorum respectively. To narrow down the active principle, the most promising extracts were separated by preparative HPLC and the resulting fractions tested in bioassays. Chaetoglobosins were identified as active compounds produced by C. globosum. CONCLUSIONS: The bioassays revealed C. aureum and C. cochliodes as promising candidates for use in biocontrol. Both showed remarkably good activity against the prominent plant pathogen P. infestans. SIGNIFICANCE AND IMPACT OF THE STUDY: We provide the first systematic study comparing six different Chaetomium species with regard to their use as biocontrol agents.
Asunto(s)
Antibiosis , Antifúngicos/farmacología , Agentes de Control Biológico/farmacología , Chaetomium/fisiología , Hongos/crecimiento & desarrollo , Antifúngicos/análisis , Ascomicetos/efectos de los fármacos , Ascomicetos/crecimiento & desarrollo , Agentes de Control Biológico/análisis , Botrytis/efectos de los fármacos , Botrytis/crecimiento & desarrollo , Chaetomium/crecimiento & desarrollo , Hongos/efectos de los fármacos , Fusarium/efectos de los fármacos , Fusarium/crecimiento & desarrollo , Alcaloides Indólicos/análisis , Alcaloides Indólicos/farmacología , Fenotipo , Phytophthora infestans/efectos de los fármacos , Phytophthora infestans/crecimiento & desarrolloRESUMEN
As the most abundant macromolecules in nature, lignocelluloses are served as a promising and renewable source for sustainable production of high value chemical compounds. In present work, extrusion pretreatment with 23% (w/w) distilled water, 2% (w/w) glycerol and 1 g/L NaHCO3 as moisture agent, not only reduced the particle size, crystallinity and component contents (cellulose, hemicelluloses and lignin) of rice straw, but also effectively enhanced chaetoglobosin A yield and degradation rate of rice straw by C. globosum CGMCC 6882. Meanwhile, mycelial biomass of C. globosum CGMCC 6882 increased from 2.9 g/L to 7.0 g/L, mycelia growth time reduced by 2 days and chaetoglobosin A titer increased from 108.4 mg/L to 270.2 mg/L, representing an increase of 149.3%. Furthermore, degradation rate of rice straw by C. globosum CGMCC 6882 increased from 28.93% to 65.38%. This work provides a good guidance for production of chaetoglobosin A from lignocelluloses.
Asunto(s)
Chaetomium/crecimiento & desarrollo , Alcaloides Indólicos/metabolismo , Lignina , Oryza/química , Lignina/química , Lignina/metabolismo , Lignina/farmacologíaRESUMEN
Endophytic fungus, as a new kind of microbial resources and separated from plants, has attracted increasing attention due to its ability to synthesize the same or similar bioactive secondary metabolites as the host plants. Nevertheless, the effects of the symbiotic relationship between microorganisms and elicitors existed in host plant on metabolite production are not adequately understood. In the present work, the impacts of elicitors (ginseng saponin and puerarin) and symbiotic microorganisms on endophytic fungus Chaetomium globosum CGMCC 6882 synthesizing polysaccharide were evaluated. Results show that the polysaccharide titers increased from 2.36 to 3.88 g/L and 3.67 g/L with the addition of 16 µg/L ginseng saponin and puerarin, respectively. Moreover, the maximum polysaccharide titer reached 4.55 g/L when C. globosum CGMCC 6882 was co-cultured with UV-irradiated G. pentaphyllum. This work brings a significant contribution to the research and interpretation of the relationship between endophytic fungus and its host plant.
Asunto(s)
Chaetomium/crecimiento & desarrollo , Polisacáridos Fúngicos , Gynostemma/microbiología , Polisacáridos Fúngicos/biosíntesis , Polisacáridos Fúngicos/química , Polisacáridos Fúngicos/aislamiento & purificaciónRESUMEN
Miscanthus sinensis Andersson is a pioneer plant species that grows naturally at mining sites. Miscanthus sinensis can detoxify aluminium (Al) by producing phytosiderophores, such as chlorogenic acid, citric acid, and malic acid, and localizing Al in cell walls. Root-endophytic Chaetomium cupreum, which produces microbial siderophores, enhances Al tolerance in M. sinensis. However, we could not determine whether the siderophores produced by C. cupreum actually enhance Al tolerance in M. sinensis, because the microbial siderophores have not yet been identified in previous research. The purpose of this study was to clarify how C. cupreum chemically increases Al tolerance in M. sinensis under acidic mining site conditions, especially considering siderophores. Using instrumental analyses, the siderophore produced by C. cupreum was identified as oosporein. Comparison of the stability constant between Al and phytosiderophores and oosporein indicated that oosporein could detoxify Al similarly to chlorogenic acid, which shows higher stability constant than citric acid and malic acid. Inoculation test of C. cupreum onto M. sinensis in acidic mine soil showed that C. cupreum promoted seedling growth, and enhanced Al tolerance via inducing chlorogenic-acid production and producing oosporein. These results suggested that C. cupreum could chemically enhance Al tolerance and might promote growth via reducing excessive Al in cell walls, the main site of Al accumulation. In addition, the chemical enhancement of Al tolerance by C. cupreum might be important for M. sinensis to adapt to acidic mining sites.
Asunto(s)
Aluminio/toxicidad , Benzoquinonas/metabolismo , Chaetomium/crecimiento & desarrollo , Ácido Clorogénico/metabolismo , Raíces de Plantas , Poaceae , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Poaceae/crecimiento & desarrollo , Poaceae/microbiologíaRESUMEN
The increasing use of plastics in human activities has resulted in an enormous amount of residues which became a matter of great environmental concern. Scientific studies on the microbial degradation of natural and synthetic molecules show the potential of fungal application on cleaning technologies. The biodegradation of PCL (polycaprolactone) and PVC (polyvinyl chloride) films by Aspergillus brasiliensis (ATCC 9642), Penicillium funiculosum (ATCC 11797), Chaetomium globosum (ATCC 16021), Trichoderma virens (ATCC 9645), and Paecilomyces variotii (ATCC 16023) was studied. According to ISO 846-1978-"Testing of Plastics - Influence of fungi and bacteria", samples of the studied polymers were inoculated with a mix suspension of 106 fungal inoculum and maintained in moisture glass chambers in a bacteriological incubator at 28 °C for 28 days. The samples were analyzed by means of morphological and color changes, mass loss, optical microscopy (OM), and scanning electron microscopy (SEM) after 28 days of culturing. After the incubation period, visual observations of the PCL films showed many micropores and cracks, pigmentation, surface erosion and hyphal adhesion on the sample surfaces, and a mass loss of up to 75%. On the contrary, there was no evidence of PVC biodegradation, such as changes in color and significant mass loss. Chaetomium globosum ATCC 16021 was a pioneer in the colonization and attack of PCL, resulting in significant mass losses. Although PVC was less attacked by the ascomycete, the polymer supported the adhesion and growth of its fertile structures (perithecia), suggesting the fungal potential to degrade both plastics.
Asunto(s)
Chaetomium/metabolismo , Poliésteres/metabolismo , Cloruro de Polivinilo/metabolismo , Biodegradación Ambiental , Chaetomium/crecimiento & desarrollo , Hongos/metabolismo , Hifa/crecimiento & desarrollo , Hifa/metabolismoRESUMEN
The Fenton reaction as an oxidative degradation process was used for industrial chemical wastewater (ICW) pretreatment. The biodegradation of pretreated ICW was performed, in aqueous environment under aerobic condition, by a defined fungal consortium. The central composite design (CCD) was used to study the effect of nitrogen and phosphorus addition and the concentration of the pollution on the removal of polyvinyl alcohol (PVA) and organic compounds. The interaction between parameters was modeled using the response surface methodology (RSM). Results of optimization showed COD, PVA and color removal yields of 97.8%, 98.5% and 99.75%, respectively with a supplementof 1.4â¯gL-1 of (NH4)2SO4, 1.2â¯gL-1 of KH2PO4 and 75% of concentrated ICW. Enzymatic analysis proved that laccase and lignin peroxidase were involved in the biodegradation with 45 UIL-1 and 450 UIL-1, respectively. Furthermore, the analysis of metabolic products using Fourier transforms infrared spectroscopy (FTIR) and nuclear magnetic resonance (1HNMR) showed clearly the mineralization of organic compounds and the formation of formic acid and ethanol. Therefore, the effective treatment of ICW was achieved by developing an integrated chemical and biological process which met the requirement for a safety effluent respectful for environment without risks for public health.
Asunto(s)
Hongos/crecimiento & desarrollo , Peróxido de Hidrógeno/química , Hierro/química , Polivinilos/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Aspergillus/crecimiento & desarrollo , Biodegradación Ambiental , Chaetomium/crecimiento & desarrollo , Residuos Industriales/análisis , Consorcios Microbianos , Rhizopus/crecimiento & desarrolloRESUMEN
Two putative type III polyketide synthase genes (PKS) were identified from Sordariomycetes fungi. These two type III PKS genes from Sordaria macrospora (SmPKS) and Chaetomium thermophilum (CtPKS), shared 59.8% sequence identity. Both, full-length and truncated versions of type III PKSs were successfully cloned and overexpressed in a bacterial host, Escherichia Coli BL21 (DE3) using a N-terminus hexa-histidine tag. The full-length and the truncated construct of PKSs showed similar activity profiles, suggesting that additional amino acid residues at the C-terminal of both SmPKS and CtPKS may not be involved in catalytic functions. We demonstrate that these two recombinant polyketide synthases could efficiently synthesize tri- and tetraketide pyrones, resorcinols and resorcylic acids using various acyl-CoAs (C4-C20) as starter units. The truncated S. macrospora polyketide synthases (TrSmPKS) showed a maximum of 7.0â¯×â¯104â¯s-1â¯M-1 catalytic efficiency towards stearoyl-CoA.Whereas, truncated C. thermophilum polyketide synthases (TrCtPKS) preferred the long-chain acyl-CoA starter arachidoyl-CoA, to produce pentaketide and hexaketide resorcinols with a high catalytic efficiency of 6.2â¯×â¯104â¯s-1â¯M-1. Homology model and substrate docking analyses suggest a shorter distance between sulfur of catalytic Cys152 and thioester carbonyl group of arachidoyl-CoA as well as stronger imidazolium-thiolate ion pair distance in TrCtPKS between catalytic Cys152-His309 compared to TrSmPKS- arachidoyl CoA complex. Enhanced binding interactions of CtPKS residues forming intermolecular contacts at the active site could be attributed to its high specificity towards arachidoyl-CoA. This study reports the functional characterization of two fungal type III polyketide synthases, SmPKS and CtPKS with high catalytic efficiency from S. macrospora and C. thermophilum respectively. Furthermore, the results suggested that the both SmPKS and CtPKS could be attractive targets for protein engineering to discern the unique substrate specificity and catalytic efficiency.
Asunto(s)
Acilcoenzima A/metabolismo , Chaetomium/enzimología , Sintasas Poliquetidas/metabolismo , Pironas/metabolismo , Sordariales/enzimología , Catálisis , Dominio Catalítico , Chaetomium/genética , Chaetomium/crecimiento & desarrollo , Clonación Molecular , Cinética , Modelos Moleculares , Sintasas Poliquetidas/genética , Sordariales/genética , Sordariales/crecimiento & desarrollo , Especificidad por SustratoRESUMEN
Catalase-peroxidases represent one important subfamily of ancestral antioxidant enzymes originally evolved in bacteria for the protection against various forms of oxidative stress. KatG genes coding for these bifunctional catalase-peroxidases were during their peculiar evolution transferred from Bacteroidetes to the fungal phylum Ascomycota via a horizontal gene transfer event. Here we analyse a newly discovered fungal katG gene without introns coding for a thermostable catalase-peroxidase from Chaetomium thermophilum var. dissitum and compare it with closely related thermophilic and mesophilic katGs and their translation products. We show that CthediskatG gene resembling its bacterial counterparts has a typical eukaryotic transcription start site and also contains a conserved eukaryotic polyadenylation signal behind its 3' terminus. Moreover, we have detected polyA tails in corresponding transcripts of katG from two different mRNA libraries of C. thermophilum var. disstum. Although otherwise highly conserved, only in katG genes of two C. thermophilum variants a unique 60â¯bp long deletion leading in the translated product with high probability to a modified loop and thus access to the prosthetic heme group was observed. We also present an updated molecular phylogeny revealing the evolutionary position of fungal thermostable catalase-peroxidases within a robust phylogenetic tree of the whole KatG subfamily.
Asunto(s)
Catalasa/genética , Chaetomium/genética , Proteínas Fúngicas/genética , Peroxidasa/genética , Secuencia de Aminoácidos , Catalasa/química , Catalasa/metabolismo , Dominio Catalítico , Chaetomium/enzimología , Chaetomium/crecimiento & desarrollo , Secuencia Conservada , Estabilidad de Enzimas , Evolución Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Expresión Génica , Calor , Modelos Moleculares , Peroxidasa/química , Peroxidasa/metabolismo , Filogenia , Conformación Proteica en Hélice alfaRESUMEN
AIMS: The aim of this study was to characterize a fungal endophyte Y3 from pigeon pea (Cajanus cajan [L.] Millsp), as a novel producer of vitexin, and its culture medium optimization and antioxidant activity. METHODS AND RESULTS: The endophyte from the leaves of pigeon pea was identified as Dichotomopilus funicola by the morphological and molecular characteristics. The most important medium variables affecting vitexin production in liquid culture of D. funicola Y3 were screened by Plackett-Burman design, and three culture medium constituents (i.e. l-phenylalanine, salicylic acid and CuSO4 ·5H2 O) were identified to play significant roles in vitexin production. The most significant factors were further optimized using by central composite design with response surface methodology. The DPPH radical-scavenging assay indicated that fungal vitexin exhibited notable antioxidant activity with an EC50 value of 164 µg l-1 . CONCLUSIONS: First, a novel endophyte vitexin-producing Dichotomopilus funicola Y3 was isolated from pigeon pea (Cajanus cajan[L.] Millsp.). The maximum vitexin yield was obtained as 78·86 mg l-1 under the optimum culture medium constituents: 0·06 g l-1 l-phenylalanine, 0·21 g l-1 salicylic acid, and 0·19 g l-1 CuSO4 ·5H2 O in medium, which is 4·59-fold higher than that in the unoptimized medium. Also, fungal vitexin clearly demonstrated its antioxidant potential. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings provide an alternative source for large-scale production of vitexin by endophytic fungal fermentation and have a promising prospect in food and pharmaceutical industry.
Asunto(s)
Antioxidantes/metabolismo , Apigenina/metabolismo , Cajanus/microbiología , Chaetomium/metabolismo , Medios de Cultivo/química , Endófitos/metabolismo , Animales , Chaetomium/genética , Chaetomium/crecimiento & desarrollo , Chaetomium/aislamiento & purificación , Medios de Cultivo/metabolismo , Endófitos/genética , Endófitos/crecimiento & desarrollo , Endófitos/aislamiento & purificación , Hojas de la Planta/microbiologíaRESUMEN
Sensing the environmental signals, the canonical Gα-cAMP/PKA pathway modulates mycelial growth and development, and negatively regulates some secondary metabolism in filamentous fungi, e.g. aflatoxin in Aspergillus nidulans. Here we report the characterization of this signaling pathway in Chaetomium globosum, a widely spread fungus known for synthesizing abundant secondary metabolites, e.g. chaetoglobosin A (ChA). RNAi-mediated knockdown of a putative Gα-encoding gene gna-1, led to plural changes in phenotype, e.g. albino mycelium, significant restriction on perithecium development and decreased production of ChA. RNA-seq profiling and qRT-PCR verified significantly fall in expression of corresponding genes, e.g. pks-1 and CgcheA. These defects could be restored by simultaneous knock-down of the pkaR gene encoding a regulatory subunit of cAMP-dependent protein kinase A (PKA), suggesting that pkaR had a negative effect on the above mentioned traits. Confirmatively, the intracellular level of cAMP in wild-type strain was about 3.4-fold to that in gna-1 silenced mutant pG14, and addition of a cAMP analog, 8-Br-cAMP, restored the same defects, e.g., the expression of CgcheA. Furthermore, the intracellular cAMP in gna-1 and pkaR double silenced mutant was approaching the normal level. The following activity inhibition experiment proved that the expression of CgcheA was indeed regulated by PKA. Down-regulation of LaeA/VeA/SptJ expression in gna-1 mutant was also observed, implying that Gα signaling may crosstalk to other regulatory pathways. Taken together, this study proposes that the heterotrimeric Gα protein-cAMP/PKA signaling pathway positively mediates the sexual development, melanin biosynthesis, and secondary metabolism in C. globosum.
Asunto(s)
Chaetomium/crecimiento & desarrollo , Chaetomium/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Subunidades alfa de la Proteína de Unión al GTP/metabolismo , Alcaloides Indólicos/metabolismo , Pigmentación , Chaetomium/citología , Chaetomium/genética , Proteínas Fúngicas/genética , Genómica , Melaninas/biosíntesis , Interferencia de ARN , Transducción de Señal , Transcripción GenéticaRESUMEN
The application of microparticle-enhanced cultivation (MPEC) is an attractive method to control mycelial morphology, and thus enhance the production of metabolites and enzymes in the submerged cultivations of filamentous fungi. Unfortunately, most literature data deals with the spore-agglomerating species like aspergilli. Therefore, the detailed quantitative study of the morphological evolution of four different fungal species (Aspergillus terreus, Penicillium rubens, Chaetomium globosum, and Mucor racemosus) based on the digital analysis of microscopic images was presented in this paper. In accordance with the current knowledge, these species exhibit different mechanisms of agglomerates formation. The standard submerged shake flask cultivations (as a reference) and MPEC involving 10 µm aluminum oxide microparticles (6 g·L-1 ) were performed. The morphological parameters, including mean projected area, elongation, roughness, and morphology number were determined for the mycelial objects within the first 24 hr of growth. It occurred that heretofore observed and widely discussed effect of microparticles on fungi, namely the decrease in pellet size, was not observed for the species whose pellet formation mechanism is different from spore agglomeration. In the MPEC, C. globosum developed core-shell pellets, and M. racemosus, a nonagglomerative species, formed the relatively larger, compared to standard cultures, pellets with distinct cores.
Asunto(s)
Óxido de Aluminio/metabolismo , Aspergillus/crecimiento & desarrollo , Chaetomium/crecimiento & desarrollo , Mucor/crecimiento & desarrollo , Penicillium/crecimiento & desarrollo , Aspergillus/efectos de los fármacos , Adhesión Celular , Chaetomium/efectos de los fármacos , Microscopía , Mucor/efectos de los fármacos , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Penicillium/efectos de los fármacosRESUMEN
Indoor mold due to water damage causes serious human respiratory disorders, and the remediation to homes, schools, and businesses is a major expense. Prevention of mold infestation of building materials would reduce health problems and building remediation costs. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit yeasts and a limited number of filamentous fungi. The purpose of this research was to determine the possible inhibitory activity of nonsteroidal anti-inflammatory drugs (NSAIDs) on germination, fungal growth, and reproduction of Chaetomium globosum and other important filamentous fungi that occur in water-damaged buildings. Several NSAIDs were found to inhibit C. globosum germination, growth, and reproduction. The most effective NSAIDs inhibiting C. globosum were ibuprofen, diflunisal, and diclofenac. Fusarium oxysporum, Fusarium solani, Aspergillus niger, and Stachybotrys atra were also tested on the various media with similar results obtained. However, F. oxysporum and A. niger exhibited a higher level of resistance to aspirin and NaSAL when compared to the C. globosum isolates. The inhibition exhibited by NSAIDs was variable depending on growth media and stage of fungal development. These compounds have a great potential of inhibiting fungal growth on building materials such as gypsum board. Formulations of sprays or building materials with NSAID-like chemical treatments may hold promise in reducing mold in homes and buildings.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Antifúngicos/farmacología , Proliferación Celular/efectos de los fármacos , Chaetomium/crecimiento & desarrollo , Germinación/efectos de los fármacos , Acetaminofén/farmacología , Aspergillus/efectos de los fármacos , Aspergillus/crecimiento & desarrollo , Aspirina/farmacología , Chaetomium/efectos de los fármacos , Diclofenaco/farmacología , Diflunisal/farmacología , Fusarium/efectos de los fármacos , Fusarium/crecimiento & desarrollo , Humanos , Ibuprofeno/farmacología , Enfermedades Pulmonares Fúngicas/prevención & control , Pruebas de Sensibilidad Microbiana , Micosis/prevención & control , Stachybotrys/efectos de los fármacos , Stachybotrys/crecimiento & desarrolloRESUMEN
Fusarium sporotrichioides, is a common soil-borne plant pathogen causing dry rot of potato in Northeast China. The objective of this study was to identify the main antifungal substances from Chaetomium globosum W7 against F. sporotrichioides. Strain W7 can significantly inhibit F. sporotrichioides without direct contact, suggesting that its antifungal substance was extracellular, and the solubility of this antifungal substance in ethyl acetate was superior to that in water. Acetone was selected as the optimum solvent for the extraction of the metabolites of C. globosum. Metabolites were then separated with thin-layer chromatography. Following antifungal tests on bands, a dark brown band with Rf value of 0.20 was determined as the antifungal substance, and identified as chaetoglobosin A. The antifungal activity test showed that the minimum inhibitory concentration of chaetoglobosin A to F. sporotrichioides was 9.45-10.50 µg/mL, IC50 being 4.344 µg/mL. Chaetoglobosin A also proved to have an excellent preventive effect on potato dry rot caused by F. sporotrichioides. To summarize, chaetoglobosin A was identified as the main active substance of C. globosum to inhibit F. sporotrichioides for the first time, and demonstrated a potential application value in agriculture.
Asunto(s)
Antifúngicos/aislamiento & purificación , Chaetomium/crecimiento & desarrollo , Fusarium/efectos de los fármacos , Alcaloides Indólicos/aislamiento & purificación , Antifúngicos/farmacología , Chaetomium/metabolismo , Cromatografía en Capa Delgada , Alcaloides Indólicos/farmacología , Pruebas de Sensibilidad Microbiana , Solanum tuberosum/microbiologíaRESUMEN
This study investigated 46 Chaetomium strains isolated from soil and compost from China. In total 14 species were recognised, of which seven were described as new species (i.e. Chaetomium angulare, Chaetomium cirrhata, Chaetomium heterothallicum, Chaetomium laterale, Chaetomium longiciliata, Chaetomium microthecia, Chaetomium uniseriatum). Growth temperature profiles of these fungi revealed that 11 species are mesophilic; C. angulare and Chaetomium jodhpurense are thermotolerant; Chaetomium thermophilum var. dissitum is thermophilic, with temperature maxima above 50 °C. Among the 46 strains, 39 were shown to be homothallic. Mating experiments were conducted for the remaining seven strains that are morphologically and phylogenetically closely related. The results of the mating experiment, together with the four-locus (ITS, LSU, RPB2, TUB) phylogeny and a pairwise homoplasy index (PHI) test, supported the division of these seven additional strains into two heterothallic species that are herein described as C. heterothallicum and C. uniseriatum. A three-locus (ITS, LSU, TUB) phylogenetic tree based on all currently accepted species that have available type-derived sequences revealed that Chaetomium species clearly grouped in six phylogenetic groups which showed a certain correspondence with their morphology and temperature profiles.
Asunto(s)
Chaetomium/clasificación , Chaetomium/aislamiento & purificación , Variación Genética , Filogenia , Microbiología del Suelo , Chaetomium/genética , Chaetomium/crecimiento & desarrollo , China , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Genes del Tipo Sexual de los Hongos , ARN Polimerasa II/genética , ARN Ribosómico/genética , Análisis de Secuencia de ADN , Suelo , Temperatura , Tubulina (Proteína)/genéticaRESUMEN
Indoor fungi are a worldwide problem causing negative health effects for infected building's occupants and even deterioration of building structures. Different fungal species affect buildings and their inhabitants differently. Therefore, rapid and accurate identification of fungi to the species level is essential for health risk assessment and building remediation. This study focuses on molecular identification of two common indoor fungal genera: Stachybotrys and Chaetomium. This study proposes two new DNA barcode candidates for Stachybotrys and Chaetomium: the gene encoding mitogen activated protein kinase (hogA) and the intergenic region between histone 3 and histone 4 (h3-h4) as well as it introduces a rapid - 3.5h - protocol for direct Stachybotrys and Chaetomium species identification, which bypasses culture cultivation, DNA extraction and DNA sequencing.
Asunto(s)
Contaminación del Aire Interior/análisis , Chaetomium/genética , Chaetomium/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Stachybotrys/genética , Stachybotrys/aislamiento & purificación , Microbiología del Aire , Secuencia de Bases , Chaetomium/clasificación , Chaetomium/crecimiento & desarrollo , Código de Barras del ADN Taxonómico/métodos , ADN de Hongos/análisis , ADN de Hongos/aislamiento & purificación , Monitoreo del Ambiente/métodos , Genes Fúngicos , Histonas/genética , Proteínas Quinasas Activadas por Mitógenos/genética , Filogenia , Medición de Riesgo/métodos , Análisis de Secuencia de ADN/métodos , Stachybotrys/clasificación , Stachybotrys/crecimiento & desarrollo , Factores de TiempoRESUMEN
Fungal growth in indoor environments is associated with many negative health effects. Many studies focus on brown- and white-rot fungi and their effect on wood, but there is none that reveals the influence of soft-rot fungi, such as Stachybotrys spp. and Chaetomium spp., on the structure of building materials such as plywood and gypsum wallboard. This study focuses on using micro-computed tomography (microCT) to investigate changes of the structure of plywood and gypsum wallboard during fungal degradation by S. chartarum and C. globosum. Changes in the materials as a result of dampness and fungal growth were determined by measuring porosity and pore shape via microCT. The results show that the composition of the building material influenced the level of penetration by fungi as shown by scanning electron microscopy (SEM). Plywood appeared to be the most affected, with the penetration of moisture and fungi throughout the whole thickness of the sample. Conversely, fungi grew only on the top cardboard in the gypsum wallboard and they did not have significant influence on the gypsum wallboard structure. The majority of the observed changes in gypsum wallboard occurred due to moisture. This paper suggests that the mycelium distribution within building materials and the structural changes, caused by dampness and fungal growth, depend on the type of the material.
Asunto(s)
Sulfato de Calcio , Chaetomium/crecimiento & desarrollo , Materiales de Construcción/microbiología , Stachybotrys/crecimiento & desarrollo , Madera/microbiología , Microtomografía por Rayos X/métodos , Chaetomium/ultraestructura , Materiales de Construcción/análisis , Microscopía Electrónica de Rastreo/métodos , Micelio/ultraestructura , Porosidad , Stachybotrys/ultraestructura , Madera/químicaRESUMEN
In this case, the authors report Chaetomium globosum as a cause of invasive pulmonary infection in a patient with Wegener's granulomatosis. Fungal hyphae (KOH and Calcofluor) were seen on direct microscopy of lung biopsy sample and bronchoalveolar lavage (BAL) sample. C. globosum isolated on culture clinched the diagnosis of invasive pulmonary infection by Chaetomium spp. A positive galactomannan of serum and BAL was repeatedly seen and was utilised for follow-up and as prognostic marker in patient management. The patient was successfully treated with liposomal amphotericin B followed by voriconazole. All the Chaetomium infections reported till date since 1980 are reviewed. Chaetomium spp. with its unique ecology has a hidden clinical potential to cause invasive mould infections.
Asunto(s)
Líquido del Lavado Bronquioalveolar/química , Chaetomium , Granulomatosis con Poliangitis/complicaciones , Enfermedades Pulmonares Fúngicas/microbiología , Mananos/análisis , Chaetomium/clasificación , Chaetomium/crecimiento & desarrollo , Chaetomium/aislamiento & purificación , Reacciones Falso Positivas , Femenino , Galactosa/análogos & derivados , Humanos , Pulmón/microbiología , Enfermedades Pulmonares Fúngicas/complicaciones , Enfermedades Pulmonares Fúngicas/diagnóstico , Mananos/sangre , Persona de Mediana Edad , Senos Paranasales/cirugía , Sinusitis/complicaciones , Sinusitis/diagnóstico , Sinusitis/cirugíaRESUMEN
The complicated process of eukaryotic ribosome biogenesis involves about 200 assembly factors that transiently associate with the nascent pre-ribosome in a spatiotemporally ordered way. During the early steps of 60S subunit formation, several proteins, collectively called A3 cluster factors, participate in the removal of the internal transcribed spacer 1 (ITS1) from 27SA3 pre-rRNA. Among these factors is the conserved hetero-trimeric Nop7-Erb1-Ytm1 complex (or human Pes1-Bop1-Wdr12), which is removed from the evolving pre-60S particle by the AAA ATPase Rea1 to allow progression in the pathway. Here, we clarify how Ytm1 and Erb1 interact, which has implications for the release mechanism of both factors from the pre-ribosome. Biochemical studies show that Ytm1 and Erb1 bind each other via their ß-propeller domains. The crystal structure of the Erb1-Ytm1 heterodimer determined at 2.67Å resolution reveals an extended interaction surface between the propellers in a rarely observed binding mode. Structure-based mutations in the interface that impair the Erb1-Ytm1 interaction do not support growth, with specific defects in 60S subunit synthesis. Under these mutant conditions, it becomes clear that an intact Erb1-Ytm1 complex is required for 60S maturation and that loss of this stable interaction prevents ribosome production.
Asunto(s)
Proteínas Fúngicas/metabolismo , Proteínas Ribosómicas/química , Proteínas Ribosómicas/metabolismo , Chaetomium/genética , Chaetomium/crecimiento & desarrollo , Cristalografía por Rayos X , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Modelos Moleculares , Complejos Multiproteicos , Mutación , Biogénesis de Organelos , Conformación Proteica , Estructura Terciaria de Proteína , Proteínas Ribosómicas/genética , Ribosomas/metabolismo , Saccharomyces cerevisiae/genéticaRESUMEN
Fungi are an important class of human pathogens for which considerable research has gone into defeating them. The photodynamic effects of rose bengal (RB), phloxine B (PB), azure A (AA), and toluidine blue O (TBO) dyes to inhibit Aspergillus fumigatus, Aspergillus niger, Trichoderma viride, Penicillium funiculosum, and Chaetomium globosum were investigated grafted to nano- and micro-structured fabrics. Three antifungal tests conducted: broth microdilution test of free dyes, zone of inhibition and quantitative antifungal assays on fabrics grafted with dyes. In the broth microdilution test, free RB displayed the lowest MIC at 32 µM to inhibit visible hyphal growth and germination but the antifungal ability of MIC for other photosensitizers below 63 µM was insignificant. RB and PB showed lower MIC than AA and TBO. In the inhibition zone tests, nanostructured fabrics grafted with RB and PB did not display fungal growth on the surface. Most microstructured fabrics grafted with AA and TBO showed little inhibition. In quantitative antifungal assay, nanostructured fabrics grafted with RB has the largest inhibition rate on T. viride and the lowest inhibition rate on P. funiculosum and the results showed the increasing inhibition rate in the order of AA < TBO < PB < RB.