947 resultados para brown-rot fungi
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This study aimed at evaluating the mechanical, physical and biological properties of laminated veneer lumber (LVL) made from Pinus oocarpa Schiede ex Schltdl (PO) and Pinus kesiya Royle ex Gordon (PK) and at providing a nondestructive characterization thereof. Four PO and four PK LVL boards from 22 randomly selected 2-mm thickness veneers were produced according to the following characteristics: phenol-formaldehyde (190 g/m(2)), hot-pressing at 150A degrees C for 45 min and 2.8 N/mm(2) of specific pressure. After board production, nondestructive evaluation was conducted, and stress wave velocity (v (0)) and dynamic modulus of elasticity (E (Md) ) were determined. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (E (M) ), modulus of rupture (f (M) ), compression strength parallel to grain (f (c,0)), shear strength parallel to glue-line (f (v,0)), shear strength perpendicular to glue-line (f (v,90)), thickness swelling (TS), water absorption (WA), and permanent thickness swelling (PTS) for 2, 24, and 96-hour of water immersion. Biological property was also evaluated by measuring the weight loss by Trametes versicolor (Linnaeus ex Fries) Pilat (white-rot) and Gloeophyllum trabeum (Persoon ex Fries.) Murrill (brown-rot). After hot-pressing, no bubbles, delamination nor warping were observed for both species. In general, PK boards presented higher mechanical properties: E (M) , E (Md) , f (M) , f (c,0) whereas PO boards were dimensionally more stable, with lower values of WA, TS and PTS in the 2, 24, and 96-hour immersion periods. Board density, f (v,0), f (v,90) and rot weight loss were statistically equal for PO and PK LVL. The prediction of flexural properties of consolidated LVL by the nondestructive method used was not very efficient, and the fitted models presented lower predictability.
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The success in the adoption of peach integrated production (IP) was evaluated in small orchards of the Parana State. The importance of specific technical accompaniment; points of strangulating in adoption of technology and the classification of the areas to IP conformity were evaluated. The seasons 2005/2006 (without IP orientation) and 2006/2007 (with IP orientation) were compared considering 20 producers who were oriented monthly to attend the minimum requisites. The incidence of peach rust (Tranzschelia discolor) and of brown rot (Monilinia fructicola) in full bloom was evaluated in 2006/2007 and 2007/2008 seasons, as biological parameters to accompany the efficiency of system adoption. After the technical accompaniment in 2007/2008 season, the software APOIA-Novo Rural-PI (APOIA-PI) was applied to measure the conformity to IP in peach orchards. The conformity index of each orchard was compared to the minimum requisite to classify as IP (0.7). The major difficulties in register of field book were: pests monitoring; collect of climate data and the harvest evaluation. The technical accompaniment increased in 60% the conformity in use of field book. In 2007/2008 season, the brown rot incidence increased in some areas, caused by not following IP recommendations. The inadequate management caused the increment in pathogen inoculum, promoting the disease development in peach orchards. The APOIA-PI classified two orchards as good agricultural practices (GAP) (0.7 <= conformity index >= 0.4), two as integrated production (IP) (>= 0.7) and the other orchards had conformity index lower than 0.4.
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Mechanical injuries and diseases in stone fruit are important causes for market rejection. The objectives of this research were to quantify and characterize the mechanical injuries and diseases in peaches, nectarines and plums at Sao Paulo`s wholesale market, the largest in Brazil. Incidence of injuries was assessed weekly in 1 % of the marketed fruit (2973 fruit/week), from September to December in 2003 and 2004. Mechanical injuries were the most frequent injuries in both years, ranging from 8.73% (plum) to 44.5% (nectarine) of injured fruit. There was a significant positive correlation between the incidence of postharvest mechanical injuries and postharvest diseases. Incidence of postharvest diseases varied from 2.5% to 6.6%. Cladosporium rot (Cladosporium sp.) and brown rot (Monilinia fructicola) were the most frequent diseases, and were mostly detected in the apexes of nectarines and peaches. Aurora (peach), Sunraycer (nectarine) and Gulfblaze (plum) varieties were the most susceptible to injuries and diseases. (c) 2007 Elsevier B.V. All rights reserved.
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A resistência natural ao apodrecimento se constitui numa importante propriedade da madeira. Em se tratando das madeiras provenientes do gênero Eucalyptus, tal atributo se torna ainda mais importante, uma vez que tais madeiras são, na grande maioria das vezes, de difícil tratabilidade pelos métodos de tratamento convencionais. O objetivo do presente trabalho foi determinar a resistência natural da madeira de sete espécies de eucalipto em ensaio acelerado de laboratório ao fungo causador da podridão-parda Gloeophyllum trabeum. Foram ensaiadas madeiras das espécies de Corymbia citriodora, Eucalyptus tereticornis, E. paniculata, E. pilularis, E. cloeziana, E. urophylla e E. grandis com 16 anos de idade, que cresceram na Estação Experimental de Anhembi, em São Paulo, pertencente ao Departamento de Ciências Florestais da ESALQ/USP. No que diz respeito ao apodrecimento causado pelo fungo Gloeophyllum trabeum, a madeira de eucalipto das sete espécies pode ser considerada resistente, uma vez que os valores de perda de massa foram sempre inferiores a 10%.
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Survival analysis is applied when the time until the occurrence of an event is of interest. Such data are routinely collected in plant diseases, although applications of the method are uncommon. The objective of this study was to use two studies on post-harvest diseases of peaches, considering two harvests together and the existence of random effect shared by fruits of a same tree, in order to describe the main techniques in survival analysis. The nonparametric Kaplan-Meier method, the log-rank test and the semi-parametric Cox's proportional hazards model were used to estimate the effect of cultivars and the number of days after full bloom on the survival to the brown rot symptom and the instantaneous risk of expressing it in two consecutive harvests. The joint analysis with baseline effect, varying between harvests, and the confirmation of the tree effect as a grouping factor with random effect were appropriate to interpret the phenomenon (disease) evaluated and can be important tools to replace or complement the conventional analysis, respecting the nature of the variable and the phenomenon.
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Source point treatment of effluents with a high load of pharmaceutical active compounds (PhACs), such as hospital wastewater, is a matter of discussion among the scientific community. Fungal treatments have been reported to be successful in degrading this type of pollutants and, therefore, the white-rot fungus Trametes versicolor was applied for the removal of PhACs from veterinary hospital wastewater. Sixty-six percent removal was achieved in a non-sterile batch bioreactor inoculated with T. versicolor pellets. On the other hand, the study of microbial communities by means of DGGE and phylogenetic analyses led us to identify some microbial interactions and helped us moving to a continuous process. PhAC removal efficiency achieved in the fungal treatment operated in non-sterile continuous mode was 44 % after adjusting the C/N ratio with respect to the previously calculated one for sterile treatments. Fungal and bacterial communities in the continuous bioreactors were monitored as well.
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Los materiales lignocelulósicos residuales de las actividades agroindustriales pueden ser aprovechados como fuente de lignina, hemicelulosa y celulosa. El tratamiento químico del material lignocelulósico se debe enfrentar al hecho de que dicho material es bastante recalcitrante a tal ataque, fundamentalmente debido a la presencia del polímero lignina. Esto se puede lograr también utilizando hongos de la podredumbre blanca de la madera. Estos producen enzimas lignolíticas extracelulares fundamentalmente Lacasa, que oxida la lignina a CO2. Tambien oxida un amplio rango de sustratos ( fenoles, polifenoles, anilinas, aril-diaminas, fenoles metoxi-sustituídos, y otros), lo cual es una buena razón de su atracción para aplicaciones biotecnológicas. La enzima tiene potencial aplicación en procesos tales como en la delignificación de materiales lignocelulósicos y en el bioblanqueado de pulpas para papel, en el tratamiento de aguas residuales de plantas industriales, en la modificación de fibras y decoloración en industrias textiles y de colorantes, en el mejoramiento de alimentos para animales, en la detoxificación de polutantes y en bioremediación de suelos contaminados. También se la ha utilizado en Q.Orgánica para la oxidación de grupos funcionales, en la formación de enlaces carbono- nitrógeno y en la síntesis de productos naturales complejos. HIPOTESIS: Los hongos de podredumbre blanca, y en condiciones óptimas de cultivo producen distintos tipos de enzimas oxidasas, siendo las lacasas las más adecuadas para explorarlas como catalizadores en los siguientes procesos: Delignificación de residuos de la industria forestal con el fin de aprovechar tales desechos en la alimentación animal. Decontaminación/remediación de suelos y/o efluentes industriales. Se realizarán los estudios para el diseño de bio-reactores que permitan responder a las dos cuestiones planteadas en la hipótesis. Para el proceso de delignificación de material lignocelulósico se proponen dos estrategias: 1- tratar el material con el micelio del hongo adecuando la provisión de nutrientes para un desarrollo sostenido y favorecer la liberación de la enzima. 2- Utilizar la enzima lacasa parcialmente purificada acoplada a un sistema mediador para oxidar los compuestos polifenólicos. Para el proceso de decontaminación/remediación de suelos y/o efluentes industriales se trabajará también en dos frentes: 3) por un lado, se ha descripto que existe una correlación positiva entre la actividad de algunas enzimas presentes en el suelo y la fertilidad. En este sentido se conoce que un sistema enzimático, tentativamente identificado como una lacasa de origen microbiano es responsable de la transformación de compuestos orgánicos en el suelo. La enzima protege al suelo de la acumulación de compuestos orgánicos peligrosos catalizando reacciones que involucran degradación, polimerización e incorporación a complejos del ácido húmico. Se utilizarán suelos incorporados con distintos polutantes(por ej. policlorofenoles ó cloroanilinas.) 4) Se trabajará con efluentes industriales contaminantes (alpechínes y/o el efluente líquido del proceso de desamargado de las aceitunas). The lignocellulosic raw materials of the agroindustrial activities can be taken advantage as source of lignin, hemicellulose and cellulose. The chemical treatment of this material is not easy because the above mentioned material is recalcitrant enough to such an assault, due to the presence of the lignin. This can be achieved also using the white-rot fungi of the wood. It produces extracellular ligninolitic enzymes, fundamentally Laccase, which oxidizes the lignin to CO2. The enzyme has application in such processes as in the delignification of lignocellulosic materials and in the biobleaching of fibers for paper industry, in the treatment of waste water of industrial plants, in the discoloration in textile industries, in the improvement of food for ruminants, in the detoxification of polutants and in bioremediation of contaminated soils. HYPOTHESIS: The white-rot fungi produce different types of enzymes, being the laccases the most adapted to explore them as catalysts in the following processes: Delignification of residues of the forest industry in order to take advantage of such waste in the animal feed. Decontamination of soils and / or waste waters. The studies will be conducted for the design of bio reactors that allow to answer to both questions raised in the hypothesis. For the delignification process of lignocellulosic material they propose two strategies: 1- to treat the material with the fungi 2-to use the partially purified enzyme to oxidize the polyphenolic compounds. For the soil and/or waste water decontamination process, we have: 3- Is know that the enzyme protects to the soil of the accumulation of organic dangerous compounds catalyzing reactions that involve degradation, polymerization and incorporation to complexes of the humic acid. There will be use soils incorporated into different pollutants. 4- We will work with waste waters (alpechins or the green olive debittering effluents.
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Els fongs de podridura blanca (WRF - de l'anglès: White-rot fungi) són de gran interès en l'àmbit de la bioremediació per la seva capacitat de degradar la lignina. La lacasa, un dels enzims extracel·lulars que aquests fongs excreten per degradar la lignina, pot ser utilitzada per degradar els contamiants presents en una matriu donada. Trametes versicolor ha estat estudiat per la seva capacitat de produïr aquest enzim en rersidus agrícoles com a substrats. Un primer triatge basat en la producció de CO2, la mesura de l'activitat lacasa i la quantificació de l'ergosterol han permés seleccionar els substrats on es donava un major poder oxidatiu dels cultius inoculats amb T. versicolor. Els posteriors experiments de colonització de sòls, on es monitoritzava l'activitat lacasa i l'ergosterol, han mostrat que T. vesicolor és capaç de colonitzar sòls i que té una major activitat lacasa en condicions no estèrils. També h'ha provat, mitjançant el test ND24, que T. versicolor és capaç de degradar un contaminant emergent, el naproxè, en sòls estèrils i no estèrils esmenats amb residus agrícoles.
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The toxic character of organochloride compounds, their habitual presence in many industrial effluents, and mainly the low efficiency of the current remediation processes, are important aspects that have been promoted to study new degrading technologies. Among the great number of new physical and chemical alternatives, the photochemical and electrochemical processes have been played an important role, mainly due to their high degradation capacity through relatively low-cost procedures. In these contexts biological processes, the use of white-rot fungi, or even ligninolytic enzymes produced from them, are also very promising alternatives. However, the necessity of long reaction time and the high cost of the enzyme production process are some of the drawbacks that difficult the definitive consolidation of these processes.
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Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more genomes in subsequent years. All molecular features studied now have a genomic flavour. In the future, this will help in connecting the classical field of pathology and diversity studies with the gene content of specific strains. In this review, we summarize the recent research on this bacterial pathogen, including strain classification, host range, pathogenicity determinants, regulation of virulence genes, type III effector repertoire, effector-triggered immunity, plant signalling in response to R. solanacearum, as well as a review of different new pathosystems.
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Oidiopsis haplophylli (syn. Oidiopsis sicula) was identified as the causal agent of powdery mildew diseases occurring on five ornamental species in Brazil. This disease was observed in plastic house-grown lisianthus (Eustoma grandiflorum: Gentianaceae), in nasturtium (Tropaeolum majus: Tropaeolaceae) cultivated under open field conditions and in greenhouse-grown calla lily (Zantedeschia aethiopica: Araceae), impatiens (Impatiens balsamina: Balsaminaceae) and balloon plant (Asclepias physocarpa: Asclepiadaceae). Typical disease symptoms consisted of chlorotic areas on the upper leaf surface corresponding to a fungal colony in the abaxial surface. With the disease progression, these chlorotic areas eventually turned to necrotic (brown) lesions. Fungi morphology on all hosts was similar to that described for the imperfect stage of Leveillula taurica (O. haplophylli). The Koch's postulates were fulfilled by inoculating symptom-free plants via leaf-to-leaf contact with fungal colonies. Additional inoculations using an isolate of O. haplophylli from sweet pepper (Capsicum annuum) demonstrated that it is pathogenic to all five species belonging to distinct botanical families, indicating lack of host specialization. This is the first formal report of a powdery mildew disease on lisianthus, calla lilly, impatiens and nasturtium in Brazil. It is, to our knowledge, the first report of O. haplophyllii infecting A. physocarpa, extending the host range of this atypical powdery mildew-inducing fungus. This disease might become important on these ornamental crops especially in protected cultivation and also under field conditions in hot and dry areas of Brazil.
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The continually growing worldwide hazardous waste problem is receiving much attention lately. The development of cost effective, yet efficient methods of decontamination are vital to our success in solving this problem.Bioremediation using white rot fungi, a group of basidiomycetes characterized by their ability to degrade lignin by producing extracellular LiP, MnP and laccase have come to be recognized globally which is described in detail in Chapter 1.These features provide them with tremendous advantages over other micro-organisms.Chapter 2 deals with the isolation and screening of lignin degrading enzyme producing micoro-organisms from mangrove area. Marine microbes of mangrove area has great capacity to tolerate wide fluctuations of salinitie.Primary and secondary screening for lignin degrading enzyme producing halophilic microbes from mangrove area resulted in the selection of two fungal strains from among 75 bacteria and 26 fungi. The two fungi, SIP 10 and SIP ll, were identified as penicillium sp and Aspergillus sp respectively belonging to the class Ascomycetes .Specific activity of the purified LiP was 7923 U/mg protein. The purification fold was 24.07 while the yield was 18.7%. SDS PAGE of LiP showed that it was a low molecular weight protein of 29 kDa.Zymogram analysis using crystal violet dye as substrate confirmed the peroxidase nature of the purified LiP.The studies on the ability of purified LiP to decolorize different synthetic dyes was done. Among the dyes studied, crystal violet, a triphenyl methane dye was decolorized to the greatest extent.
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This study was undertaken to isolate ligninase-producing white-rot fungi for use in the extraction of fibre from pineapple leaf agriwaste. Fifteen fungal strains were isolated from dead tree trunks and leaf litter. Ligninolytic enzymes (lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac)), were produced by solid-state fermentation (SSF) using pineapple leaves as the substrate. Of the isolated strains, the one showing maximum production of ligninolytic enzymes was identified to be Ganoderma lucidum by 18S ribotyping. Single parameter optimization and response surface methodology of different process variables were carried out for enzyme production. Incubation period, agitation, and Tween-80 were identified to be the most significant variables through Plackett-Burman design. These variables were further optimized by Box-Behnken design. The overall maximum yield of ligninolytic enzymes was achieved by experimental analysis under these optimal conditions. Quantitative lignin analysis of pineapple leaves by Klason lignin method showed significant degradation of lignin by Ganoderma lucidum under SSF
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X-rays were initially used for the inspection of special-purpose wood pieces for quantitative evaluation properties of different species. X-ray densitometry has had its use expanded ill dendroclimatology of Picea engelmannii trees. Subsequent laboratories developed applications of X-ray densitometry for environmental, wood science and technology, and related areas. This paper describes the basic methodology of X-ray densitometry applied to the eucalypt wood analysis, as well its presenting the results of applications in three areas: (i) evaluation of wood biodegradation by white rot fungi, (ii) detection of sapwood and heartwood, and (iii) determination of the effect of management oil wood properties. The wood decayed by white rot fungi was detected by X-ray densitometry with it decreasing wood density due to the biodegradation of cell wall components. The sapwood and heartwood of eucalypts were separated in response to the attenuation of X-rays, reflected by the wood anatomical structure and chemical composition. Also, Ill eucalypt trees after the application of irrigation and i characteristic wood density profiles were detected. Ill addition, the significant potential of X-ray densitometry for eucalypt wood research and analysis is discussed.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)