Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 42
Filter
1.
Bol. micol. (Valparaiso En linea) ; 33(2): 1-9, dic. 2018. ilus.
Article in Spanish | LILACS | ID: biblio-987868

ABSTRACT

Los hongos son organismos eucariontes que tienen nutrición absortiva, con presencia en los más variados ambientes y sustratos. Han sido parte de la historia del hombre y su desarrollo, siendo útiles tanto en la alimentación como en la medicina, producción de enzimas, actividad industrial y silvicultura. Sin embargo, también tienen la capacidad de producir infecciones superficiales y profundas en humanos y animales, contaminar e infectar granos, frutas, plantas y generar verdaderos desastres ecológicos.


Fungi are eukaryotic organisms, its nutrition is absorptive and they are widespread present in environment and substrates. They have been part of the history of human being and his development: they are useful as food, in medicine, enzyme production, in the industrial activity and forestry. However they have the capacity of infect superficial and deep human and animal tissues, contaminate and infect grains, fruits, plants and even produce environmental disasters.


Subject(s)
Dermatomycoses/microbiology , Environment , Fungi/pathogenicity , Yeasts , Fungi/physiology
2.
Braz. j. microbiol ; 49(1): 67-78, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889191

ABSTRACT

ABSTRACT The use of dark septate fungi (DSE) to promote plant growth can be beneficial to agriculture, and these organisms are important allies in the search for sustainable agriculture practices. This study investigates the contribution of dark septate fungi to the absorption of nutrients by rice plants and their ensuing growth. Four dark septate fungi isolates that were identified by Internal transcribed spacer phylogeny were inoculated in rice seeds (Cv. Piauí). The resulting root colonization was estimated and the kinetic parameters Vmax and Km were calculated from the nitrate contents of the nutrient solution. The macronutrient levels in the shoots, and the NO3--N, NH4+-N, free amino-N and soluble sugars in the roots, sheathes and leaves were measured. The rice roots were significantly colonized by all of the fungi, but in particular, isolate A103 increased the fresh and dry biomass of the shoots and the number of tillers per plant, amino-N, and soluble sugars as well as the N, P, K, Mg and S contents in comparison with the control treatment. When inoculated with isolates A103 and A101, the plants presented lower Km values, indicating affinity increases for NO3--N absorption. Therefore, the A103 Pleosporales fungus presented the highest potential for the promotion of rice plant growth, increasing the tillering and nutrients uptake, especially N (due to an enhanced affinity for N uptake) and P.


Subject(s)
Fungi/physiology , Oryza/growth & development , Oryza/microbiology , Ascomycota/classification , Ascomycota/genetics , Ascomycota/isolation & purification , Ascomycota/physiology , Biomass , Fungi/classification , Fungi/genetics , Fungi/isolation & purification , Nitrogen/metabolism , Oryza/metabolism , Phosphates/metabolism , Phylogeny , Plant Roots/growth & development , Plant Roots/metabolism , Plant Roots/microbiology , Potassium/metabolism
3.
Braz. j. microbiol ; 49(1): 45-53, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889199

ABSTRACT

ABSTRACT Plants response to symbiosis with arbuscular mycorrhizal fungi (AMF) under water stress is important to agriculture. Under abiotic stress conditions native fungi are more effective than exotics in improving plant growth and water status. Mycorrhization efficiency is related to soil fungi development and energy cost-benefit ratio. In this study, we assessed the effect on growth, water status and energy metabolism of Cucurbita pepo var. pepo when inoculated with native AMF from the Sonoran desert Mexico (mixed isolate and field consortium), and compared with an exotic species from a temperate region, under drought, low and high salinity conditions. Dry weights, leaf water content, water and osmotic potentials, construction costs, photochemistry and mycorrhization features were quantified. Under drought and low salinity conditions, the mixed isolate increased plant growth and leaf water content. Leaf water potential was increased only by the field consortium under drought conditions (0.5-0.9 MPa). Under high salinity, the field consortium increased aerial dry weight (more than 1 g) and osmotic potential (0.54 MPa), as compared to non-mycorrhized controls. Plants inoculated with native AMF, which supposedly diminish the effects of stress, exhibited low construction costs, increased photochemical capacity, and grew larger external mycelia in comparison to the exotic inoculum.


Subject(s)
Cucurbita/microbiology , Mycorrhizae/physiology , Fungi/physiology , Soil/chemistry , Water/analysis , Water/metabolism , Plant Leaves/growth & development , Plant Leaves/metabolism , Biomass , Cucurbita/growth & development , Cucurbita/physiology , Mycorrhizae/isolation & purification , Mycorrhizae/classification , Desert Climate , Salinity , Droughts , Fungi/isolation & purification , Fungi/classification , Mexico
4.
Mem. Inst. Oswaldo Cruz ; 113(9): e180212, 2018. tab, graf
Article in English | LILACS | ID: biblio-955119

ABSTRACT

Biofilm formation is the preferred mode of growth lifestyle for many microorganisms, including bacterial and fungal human pathogens. Biofilm is a strong and dynamic structure that confers a broad range of advantages to its members, such as adhesion/cohesion capabilities, mechanical properties, nutritional sources, metabolite exchange platform, cellular communication, protection and resistance to drugs (e.g., antimicrobials, antiseptics, and disinfectants), environmental stresses (e.g., dehydration and ultraviolet light), host immune attacks (e.g., antibodies, complement system, antimicrobial peptides, and phagocytes), and shear forces. Microbial biofilms cause problems in the hospital environment, generating high healthcare costs and prolonged patient stay, which can result in further secondary microbial infections and various health complications. Consequently, both public and private investments must be made to ensure better patient management, as well as to find novel therapeutic strategies to circumvent the resistance and resilience profiles arising from biofilm-associated microbial infections. In this work, we present a general overview of microbial biofilm formation and its relevance within the biomedical context.


Subject(s)
Biofilms/growth & development , Bacterial Physiological Phenomena , Fungi/physiology , Environmental Microbiology
5.
Braz. j. microbiol ; 48(4): 680-688, Oct.-Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-889171

ABSTRACT

ABSTRACT Sophora tomentosa is a pantropical legume species with potential for recovery of areas degraded by salinization, and for stabilization of sand dunes. However, few studies on this species have been carried out, and none regarding its symbiotic relationship with beneficial soil microorganisms. Therefore, this study aimed to evaluate the diversity of nitrogen-fixing bacteria isolated from nodules of Sophora tomentosa, and to analyze the occurrence of colonization of arbuscular mycorrhizal fungi on the roots of this legume in seafront soil. Thus, seeds, root nodules, and soil from the rhizosphere of Sophora tomentosa were collected. From the soil samples, trap cultures with this species were established to extract spores and to evaluate arbuscular mycorhizal fungi colonization in legume roots, as well as to capture rhizobia. Rhizobia strains were isolated from nodules collected in the field or from the trap cultures. Representative isolates of the groups obtained in the similarity dendrogram, based on phenotypic characteristics, had their 16S rRNA genes sequenced. The legume species showed nodules with indeterminate growth, and reddish color, distributed throughout the root. Fifty-one strains of these nodules were isolated, of which 21 were classified in the genus Bacillus, Brevibacillus, Paenibacillus, Rhizobium and especially Sinorhizobium. Strains closely related to Sinorhizobium adhaerens were the predominant bacteria in nodules. The other genera found, with the exception of Rhizobium, are probably endophytic bacteria in the nodules. Arbuscular mycorrhizal fungi was observed colonizing the roots, but arbuscular mycorhizal fungi spores were not found in the trap cultures. Therefore Sophora tomentosa is associated with both arbuscular mycorhizal fungi and nodulating nitrogen-fixing bacteria.


Subject(s)
Bacteria/isolation & purification , Fungi/isolation & purification , Mycorrhizae/isolation & purification , Sophora/microbiology , Symbiosis , Bacterial Physiological Phenomena , Bacteria/classification , Bacteria/genetics , Fungi/classification , Fungi/genetics , Fungi/physiology , Mycorrhizae/classification , Mycorrhizae/genetics , Mycorrhizae/physiology , Phylogeny , Plant Roots/microbiology , Soil Microbiology , Sophora/physiology
6.
An. bras. dermatol ; 92(4): 478-483, July-Aug. 2017. tab, graf
Article in English | LILACS | ID: biblio-886989

ABSTRACT

Abstract: Background: Histological and mycological changes during itraconazole use have not been totally established in chromoblastomycosis. Objectives: To evaluate tissue modifications in chromoblastomycosis carriers under itraconazole treatment. Methods: A histological retrospective study of 20 cases of chromoblastomycosis seen at the university hospital at the south of Brazil, during itraconazole 400 mg daily treatment. Patients were classified into two groups: plaque or tumor lesions, and underwent periodic evaluations every four months during three years. Hematoxylin-eosin stain was used to analyze epidermal modifications, inflammatory infiltrate and fibrosis, and Fontana-Masson stain for parasite evaluation. Results: Fontana-Masson stain was superior to hematoxylin-eosin stain in fungal count in the epidermis (mean difference=0.14; p<0.05). The most distinct mycosis tissue responses were registered in the dermis. Epidermal thinning, granulomatous infiltrate decrease or disappearance, fibrosis increase and quantitative/morphological changes occurred during treatment. Study limitations: Patients could not be located to have their current skin condition examined. Conclusion: Parasitic and tissue changes verified in this study can reflect the parasite-host dynamics under itraconazole action.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Skin/pathology , Chromoblastomycosis/drug therapy , Itraconazole/therapeutic use , Agricultural Workers' Diseases/microbiology , Agricultural Workers' Diseases/drug therapy , Antifungal Agents/therapeutic use , Silver Nitrate , Skin/microbiology , Biopsy , Retrospective Studies , Chromoblastomycosis/microbiology , Chromoblastomycosis/pathology , Subcutaneous Tissue , Agricultural Workers' Diseases/pathology , Fungi/physiology , Host-Parasite Interactions/physiology
7.
Braz. j. microbiol ; 48(3): 476-482, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-889147

ABSTRACT

Abstract Onychomycosis is a fungal infection of the nail caused by high densities of filamentous fungi and yeasts. Treatment for this illness is long-term, and recurrences are frequently detected. This study evaluated in vitro antifungal activities of 12 organic compounds derived from amino alcohols against standard fungal strains, such as Trichophyton rubrum CCT 5507 URM 1666, Trichophyton mentagrophytes ATCC 11481, and Candida albicans ATCC 10231. The antifungal compounds were synthesized from p-hydroxybenzaldehyde (4a-4f) and p-hydroxybenzoic acid (9a-9f). Minimum inhibitory concentrations and minimum fungicidal concentrations were determined according to Clinical and Laboratory Standards Institute protocols M38-A2, M27-A3, and M27-S4. The amine series 4b-4e, mainly 4c and 4e compounds, were effective against filamentous fungi and yeast (MIC from 7.8 to 312 µg/mL). On the other hand, the amide series (9a-9f) did not present inhibitory effect against fungi, except amide 9c, which demonstrated activity only against C. albicans. This allowed us to infer that the presence of amine group and intermediate carbon number (8C-11C) in its aliphatic side chain seems to be important for antifungal activity. Although these compounds present cytotoxic activity on macrophages J774, our results suggest that these aromatic compounds might constitute potential as leader molecules in the development of more effective and less toxic analogs that could have considerable implications for future therapies of onychomycosis.


Subject(s)
Humans , Amino Alcohols/pharmacology , Antifungal Agents/pharmacology , Fungi/drug effects , Onychomycosis/microbiology , Amino Alcohols/chemical synthesis , Antifungal Agents/chemical synthesis , Drug Evaluation, Preclinical , Fungi/classification , Fungi/physiology , Microbial Sensitivity Tests , Onychomycosis/drug therapy
8.
Braz. j. microbiol ; 48(1): 32-36, Jan.-Mar. 2017. tab, graf
Article in English | LILACS | ID: biblio-839352

ABSTRACT

Abstract Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.


Subject(s)
Actinobacteria/physiology , Fungi/physiology , Antibiosis , Phylogeny , Streptomyces/classification , Streptomyces/genetics , Brazil , RNA, Ribosomal, 16S/genetics , Actinobacteria/isolation & purification , Actinobacteria/classification , Actinobacteria/genetics
9.
Rev. argent. microbiol ; 48(4): 347-357, dic. 2016. ilus, graf, tab
Article in Spanish | LILACS | ID: biblio-1041772

ABSTRACT

El hongo Macrophomina phaseolina (Tassi) Goid., agente causal de la enfermedad denominada «pudrición carbonosa¼, provoca pérdidas significativas en la producción de cultivos como maíz, sorgo, soya y frijol en México. Este hongo, parásito facultativo, muestra amplia capacidad de adaptación a ambientes estresantes, donde existen altas temperaturas y deficiencia hídrica, condiciones frecuentes en gran parte de la agricultura de dicho país. En este trabajo se describen algunos aspectos básicos de la etiología y la epidemiología de M. phaseolina. Asimismo, se revisa la importancia que guardan las respuestas de este hongo a ambientes estresantes, particularmente la deficiencia hídrica, de acuerdo con caracteres morfológicos y del crecimiento, así como fisiológicos, bioquímicos y de patogenicidad. Finalmente, se presentan algunas perspectivas de estudio del género, que enfatizan la necesidad de mejorar su conocimiento, con base en la aplicación de herramientas tradicionales y de biotecnología, y de dilucidar mecanismos de tolerancia al estrés ambiental, extrapolables a otros microorganismos útiles al hombre.


Fungus Macrophomina phaseolina (Tassi) Goid. is the causative agent of charcoal rot disease which causes significant yield losses in major crops such as maize, sorghum, soybean and common beans in Mexico. This fungus is a facultative parasite which shows broad ability to adapt itself to stressed environments where water deficits and/or high temperature stresses commonly occur. These environmental conditions are common for most cultivable lands throughout Mexico. Here we describe some basic facts related to the etiology and epidemiology of the fungus as well as to the importance of responses to stressed environments, particularly to water deficits, based on morphology and growth traits, as well as on physiology, biochemistry and pathogenicity of fungus M. phaseolina. To conclude, we show some perspectives related to future research into the genus, which emphasize the increasing need to improve the knowledge based on the application of both traditional and biotechnological tools in order to elucidate the mechanisms of resistance to environmental stress which can be extrapolated to other useful organisms to man.


Subject(s)
Adaptation , Environment , Crop Production/economics , Fungi/growth & development , Fungi/physiology , Fungi/pathogenicity , Stress, Physiological/physiology
10.
Braz. j. microbiol ; 47(4): 807-816, Oct.-Dec. 2016. tab
Article in English | LILACS | ID: biblio-828188

ABSTRACT

Abstract The housefly Musca domestica is a worldwide insect pest that acts as a vector for many pathogenic diseases in both people and animals. The present study was conducted to evaluate the virulence of different local isolates of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea on M. domestica using two bioassay techniques: (1) adult immersion and (2) a bait method applied to both larvae and adults. The results showed evidence of a broad range of responses by both stages (larvae and adults) to the tested isolates of B. bassiana, M. anisopliae and I. fumosorosea. These responses were concentration-dependent, with mortality percentages ranging from 53.00% to 96.00%. Because it resulted in lower LC50 values and a shorter lethal time, B. bassiana (Bb-01) proved to be the most virulent isolate against both housefly larvae and adults. Sublethal doses of the tested isolates were also assessed to evaluate their effect on M. domestica fecundity and longevity. The fungal infections reduced housefly survival regardless of their sex and also decreased egg production in females.


Subject(s)
Animals , Male , Female , Fungi/physiology , Houseflies/microbiology , Pakistan , Microbial Viability , Fungi/isolation & purification , Larva/microbiology
11.
Braz. j. microbiol ; 47(4): 793-799, Oct.-Dec. 2016. tab
Article in English | LILACS | ID: biblio-828190

ABSTRACT

Abstract Triazole fungicides are used broadly for the control of infectious diseases of both humans and plants. The surge in resistance to triazoles among pathogenic populations is an emergent issue both in agriculture and medicine. The non-rational use of fungicides with site-specific modes of action, such as the triazoles, may increase the risk of antifungal resistance development. In the medical field, the surge of resistant fungal isolates has been related to the intensive and recurrent therapeutic use of a limited number of triazoles for the treatment and prophylaxis of many mycoses. Similarities in the mode of action of triazole fungicides used in these two fields may lead to cross-resistance, thus expanding the spectrum of resistance to multiple fungicides and contributing to the perpetuation of resistant strains in the environment. The emergence of fungicide-resistant isolates of human pathogens has been related to the exposure to fungicides used in agroecosystems. Examples include species of cosmopolitan occurrence, such as Fusarium and Aspergillus, which cause diseases in both plants and humans. This review summarizes the information about the most important triazole fungicides that are largely used in human clinical therapy and agriculture. We aim to discuss the issues related to fungicide resistance and the recommended strategies for preventing the emergence of triazole-resistant fungal populations capable of spreading across environments.


Subject(s)
Humans , Triazoles/poisoning , Ecosystem , Drug Resistance, Fungal , Agriculture , Fungi/drug effects , Antifungal Agents/pharmacology , Plant Diseases/microbiology , Triazoles/therapeutic use , Fungi/physiology , Fungicides, Industrial , Mycoses/microbiology , Mycoses/drug therapy , Antifungal Agents/therapeutic use
12.
Rev. argent. microbiol ; 48(4): 274-278, dic. 2016. ilus, graf, tab
Article in English | LILACS | ID: biblio-1041762

ABSTRACT

Knowledge regarding the enzymatic machinery of fungi is decisive to understand their ecological role. The species of the genus Geastrum are known to grow extremely slowly in pure culture, which makes it difficult to evaluate physiological parameters such as enzyme activity. Qualitative assays were performed on isolates of four species of this genus, showing evidence of laccase, cellulase, pectinase, amylase and lipase activity and suggesting that a wide range of carbon sources can be exploited by these species. For the first time in this genus, quantitative assays verified manganese peroxidase activity (up to 0.6 mU/g) in 30-day old cultures, as well as laccase, β-glycosidase and β-xylosidase activities.


El conocimiento de la maquinaria enzimática de un hongo es decisivo para entender su rol ecológico. Las especies del género Geastrum son conocidas por su crecimiento extremadamente lento en cultivos puros, lo que hace difícil la evaluación de parámetros fisiológicos como las actividades enzimáticas. Se realizaron ensayos cualitativos sobre aislamientos de 4 especies de este género, mostrando evidencias de actividades lacasa, celulasa, pectinasa, amilasa y lipasa, mostrando el amplio rango de fuentes de carbono que pueden ser explotadas por estas especies. Ensayos cuantitativos verificaron por primera vez en este género la actividad manganeso peroxidasa (hasta 0,6 mU/g) en cultivos de 30 días, así como también β-glucosidasa y β-xilosidasa.


Subject(s)
Fungi/enzymology , Xylosidases/isolation & purification , Biotransformation/physiology , Cellulase/isolation & purification , Laccase/isolation & purification , Fungi/physiology , Lipase/isolation & purification
13.
Braz. j. biol ; 75(3): 524-534, Aug. 2015.
Article in English | LILACS | ID: lil-761566

ABSTRACT

AbstractThe hyporheic zone (HZ), as the connecting ecotone between surface- and groundwater, is functionally part of both fluvial and groundwater ecosystems. Its hydrological, chemical, biological and metabolic features are specific of this zone, not belonging truly neither to surface- nor to groundwater. Exchanges of water, nutrients, and organic matter occur in response to variations in discharge and bed topography and porosity. Dynamic gradients exist at all scales and vary temporally. Across all scales, the functional significance of the HZ relates to its activity and connection with the surface stream. The HZ is a relatively rich environment and almost all invertebrate groups have colonized this habitat. This fauna, so-called hyporheos, is composed of species typical from interstitial environment, and also of benthic epigean and phreatic species. The hyporheic microbiocenose consists in bacteria, archaea, protozoa and fungi. The HZ provides several ecosystem services, playing a pivotal role in mediating exchange processes, including both matter and energy, between surface and subterranean ecosystems, functioning as regulator of water flow, benthic invertebrates refuge and place of storage, source and transformation of organic matter. The hyporheic zone is one of the most threatened aquatic environments, being strongly influenced by human activities, and the least protected by legislation worldwide. Its maintenance and conservation is compelling in order to preserve the ecological interconnectivity among the three spatial dimensions of the aquatic environment. Although several researchers addressed the importance of the hyporheic zone early, and most contemporary stream ecosystem models explicitly include it, very little is known about the HZ of Neotropical regions. From a biological standpoint, hyporheos fauna in Neotropical regions are still largely underestimated. This review focuses on a brief presentation of the hyporheic zone and its functions and significance as an ecotone. We also highlighted the key aspects considering also the current status of research in Neotropical regions.


ResumoA zona hiporréica, como ecótono de ligação entre a superfície e as águas subterrâneas, é parte funcional seja dos ecossistemas fluviais seja das águas subterrâneas. As características hidrológicas, as características químicas, biológicas e metabólicas são específicas desta zona, não pertencendo verdadeiramente nem a superfície nem às águas subterrâneas. Trocas de água, nutrientes e matéria orgânica ocorrem em resposta a variações na descarga, topografia do álveo e porosidade. Gradientes dinâmicos existem em todas as escalas e variam temporalmente. Em todas as escalas, o significado funcional da zona hyporheic relaciona-se com a sua conexão e atividades com a água superficial. O HZ é um ambiente relativamente rico e quase todos os grupos de invertebrados colonizaram este habitat. Esta fauna, chamada hyporheos, é composta por espécies típicas do ambiente intersticial, e também de espécies bentônicas epígeas e freáticas. A microbiocenose consiste em bactérias, arqueobactérias, fungos e protozoários. O HZ fornece vários serviços para o ecossistema, desempenhando um papel fundamental na mediação de processos de troca, incluindo seja a matéria, seja a energia, entre os ecossistemas superfíciais e os subterrâneos, funcionando como regulador do fluxo de água, de refúgio para invertebrados bentônicos e local de armazenagem, fonte e transformação de matéria orgânica. A zona hyporheic é um dos ambientes aquáticos mais ameaçados, sendo fortemente influenciado pelas atividades humanas, e um dos menos protegidos pela legislação em todo o mundo. A sua manutenção e conservação é necessaria para preservar a interconectividade ecológica entre as três dimensões espaciais do ambiente aquático. Apesar de vários pesquisadores aborem a importância da zona hyporheic a tempo, e a maioria dos modelos de ecossistemas atualmente incluí-lo de forma explicita, muito pouco se sabe sobre o HZ das regiões neotropicais. Do ponto de vista biológico, a fauna hiporréica das regiões neotropicais é ainda largamente subestimada. Esta revisão visa apresentar de forma resumida a zona hiporréica, suas funções e importância como ecótono. Também visa destacar os aspectos principais considerando também o estado actual da investigação em regiões neotropicais.


Subject(s)
Animals , Biodiversity , Fresh Water , Groundwater , Water Movements , Wetlands , Archaea/physiology , Bacterial Physiological Phenomena , Central America , Ecosystem , Fresh Water/microbiology , Fresh Water/parasitology , Fungi/physiology , Groundwater/microbiology , Groundwater/parasitology , Invertebrates/physiology , Mexico , South America
14.
Braz. j. microbiol ; 45(1): 43-47, 2014. tab
Article in English | LILACS | ID: lil-709477

ABSTRACT

Microorganisms are a source of many high-value compounds which are useful to every living being, such as humans, plants and animals. Since the process of isolating and improving a microorganism can be lengthy and expensive, preserving the obtained characteristic is of paramount importance, so the process does not need to be repeated. Fungi are eukaryotic, achlorophyllous, heterotrophic organisms, usually filamentous, absorb their food, can be either macro or microscopic, propagate themselves by means of spores and store glycogen as a source of storage. Fungi, while infesting food, may produce toxic substances such as mycotoxins. The great genetic diversity of the Kingdom Fungi renders the preservation of fungal cultures for many years relevant. Several international reference mycological culture collections are maintained in many countries. The methodologies that are most fit for preserving microorganisms for extended periods are based on lowering the metabolism until it reaches a stage of artificial dormancy . The goal of this study was to analyze three methods for potentially toxigenic fungal conservation (Castellani's, continuous subculture and lyophilization) and to identify the best among them.


Subject(s)
Fungi/isolation & purification , Fungi/physiology , Microbiological Techniques/methods , Preservation, Biological/methods
15.
Bol. micol. (Valparaiso En linea) ; 28(2): 58-70, dic. 2013. ilus
Article in Spanish | LILACS | ID: lil-708088

ABSTRACT

En estas notas micológicas, se comentan los aspectos taxonómicos, ecológicos fisiológicos y moleculares de 2 especies fúngicas filamentosas oportunistas en humanos tales como: Tritirachium oryzae y Paecilomyces formosus, poco conocidas en su distribución en Chile. Almismo tiempo se aportan datos recientes de la literatura referentes a la distribución y patología de los nuevos integrantes de de la sección Fumigati de Aspergillus, con énfasis en el complejo A. viridinutans, un grupo de especiemorfológicamente similares y generalmente oportunista en humanos y animales, las cuales no han sido biendefinidas en la últimas décadas.


In these notes, taxonomic, ecological, physiological and molecular aspects are discussed of two opportunisticfilamentous fungal species in humans, such as Tritirachium oryzae and Paecilomyces formosus, little known in its distribution in Chile. While recent literature data concerning the distribution and pathology of the newmembers of the Aspergillus section Fumigati contribute, emphasizing the complex A. viridinutans, a group ofmorphologically similar species and generally opportunistic in humans and animals did, which have not been welldefined in recent decades.


Subject(s)
Humans , Aspergillus fumigatus , Fungi/classification , Fungi/physiology , Fungi/pathogenicity , Mycoses , Chile
16.
Article in English | IMSEAR | ID: sea-162952

ABSTRACT

Aim: The study evaluated potential performance of different fungal isolates from agricultural by-products for mannanase production. Study Design: The first experiment, fungal isolates were screened for mannanase production on agar medium containing Locust Bean Gum (LBG) and total fungal count was conducted. In the second experiment, the fungal isolates were further screened for mannanase production in submerged state fermentation. Place and Duration of Study: Microbiology Research Laboratory Federal University of Technology, Akure and Postgraduate Research Laboratory, Obafemi Awolowo University Ile-Ife, Nigeria between September 2011 and March 2012. Methodology: The fungal isolates associated with some agricultural wastes were isolated on LBG containing agar medium by plate assay techniques and counted by standard microbiological methods. Mannanase production was conducted in submerged state fermentation (shaken & static) into which copra meal had been supplemented as the sole carbon source and enzyme activity was determined by dinitrosalicylic acid method. Results: In this study, 11 fungal isolates showed positive results with clear zone around their cultures. Fungal isolate 5A showed the highest activity ratio of 1.8, while the least was observed in isolate 9A12 with activity ratio of 0.64. The highest fungal counts were recorded in fermented coconut with 7.4×102 sfu/g, while cocoa pod and groundnut shell had no fungal growth. In terms of percentage occurrence of fungal isolates from selected agrowastes, it was revealed that Rhizopus japonicus had the highest occurrence of 66.67%, while the same value of 8.33% was observed for Aspergillus fumigatus, A. glaucus, R. stolonifer and Trichosporonoides oedocephalis. In fermentation broth, all the 11 isolates displayed mannanase activity ranging from 0.370 to 21.667 U/ml for static and 0.278 to 3.982 U/ml for shaken condition, with the highest mannanase activity observed with isolate 5A for both culture conditions. According to the cultural characters and microscopic morphology, the isolate 5A being the highest mannanase producer was identified as the Aspergillus fumigatus. Conclusion: In this study, fungal isolates screened and evaluated for mannanase production from agricultural by-products elaborated considerable mannanase activity and this could be exploited for prebiotic preparation.


Subject(s)
Agriculture , Fungi/analysis , Fungi/enzymology , Fungi/isolation & purification , Fungi/metabolism , Fungi/physiology , Industrial Microbiology , Industrial Waste , beta-Mannosidase/biosynthesis
17.
Electron. j. biotechnol ; 14(6): 5-5, Nov. 2011. ilus, tab
Article in English | LILACS | ID: lil-640522

ABSTRACT

The objective of this study was to investigate the effect of vermicompost, worm-bed leachate (WBL) and Glomus mosseae, an arbuscular mycorrhizal fungi (AMF), on growth of lemongrass (Cymbopogon citratus (DC.) Stapf). A response surface methodology, i.e. a three-level Box Benhen design with three repetitions and three blocks, was applied to optimize biomass production, essential oil yield and its composition. Application rates of Glomus mosseae were 0, 1 or 2 g plant-1, vermicompost 0, 5 or 10 g plant-1 and WBL 0, 10 and 20 percent. The AMF had no significant effect on the variables tested, but vermicompost had a significant effect on essential oil yield and WBL on essential oil yield, myercene concentration and shoot dry weigh (p < 0.05). It was found that lemongrass fertilized with 2.0 g G. mosseae, 5.0 g vermicompost and 20 percent worm-bed leachate would yield 0.797 percent essential oil of which 62.6 percent was citral.


Subject(s)
Oils, Volatile/chemistry , Composting , Cymbopogon/chemistry , Fungi/physiology , Mycorrhizae/physiology , Soil , Culture Media , Process Optimization
18.
Indian J Ophthalmol ; 2011 July; 59(4): 291-296
Article in English | IMSEAR | ID: sea-136192

ABSTRACT

Purpose: To determine the incidence, outcomes and establish factors determining visual prognosis of keratomycosis due to pigmented fungi in comparison with nonpigmented fungi. Materials and Methods: All culture-proven cases of fungal keratitis from January 2006 to August 2008 were drawn from a computerized database and cases with adequate documentation were analyzed for predisposing factors, clinical characteristics, microbiology and treatment methods. Outcomes of keratitis due to pigmented and nonpigmented fungi were compared using t-test and χ2 test. Results: Of 373 cases of keratomycosis during the study period, pigmented fungi were etiological agents in 117 eyes (31.3%) and nonpigmented fungi in 256 eyes (68.7%). Eyes with nonpigmented keratitis had significantly larger ulcers (14.96 mm2 ) and poorer vision (1.42 logMAR) at presentation compared to those with keratomycosis due to pigmented fungi (P=0.01). The characteristic macroscopic pigmentation was seen in only 14.5% in the pigmented keratitis group. Both groups responded favorably to medical therapy (78.1% vs. 69.1%) with scar formation (P=0.32) and showed a significant improvement in mean visual acuity compared with that at presentation (P<0.01). Visual improvement in terms of line gainers and losers in the subgroup of eyes that experienced healing was also similar. Location of the ulcer was the only factor that had significant predictive value for visual outcome (P=0.021). Conclusion: Incidence of keratomycosis due to pigmented fungi may be increasing as compared to previous data. These eyes have similar response to medical therapy and similar visual outcome compared to nonpigmented keratitis. Central ulcers have a poor visual outcome.


Subject(s)
Adult , Antifungal Agents/therapeutic use , Cicatrix/etiology , Corneal Ulcer/microbiology , Databases, Factual , Eye Infections, Fungal/drug therapy , Female , Fungi/physiology , Humans , Incidence , Keratitis/complications , Keratitis/epidemiology , Keratitis/microbiology , Keratitis/physiopathology , Male , Middle Aged , Pigmentation , Prognosis , Visual Acuity/drug effects , Wound Healing
19.
Rev. biol. trop ; 59(1): 37-52, mar. 2011. ilus, graf, tab
Article in English | LILACS | ID: lil-638044

ABSTRACT

In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF), samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee); animal feces (cattle, sheep, goat and horse); soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were idenified: Arthrobotrys oligospora (n=13); Candelabrella musiformis (n=9); and for the first time there was isolation of A. conoides (n=1) and A. dactyloides (n=1) in the country. Moreover, 16 strains from Trichoderma (n=13), Beauveria (n=1), Clonostachys (n=1) and Lecanicillium (n=1) were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA); corn meal agar (CMA); malt extract agar (MEA) and potato carrot agar (PCA). Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out of which 42.9% survived the digestive analysis. Neither A. conoides nor A. dactyloides were viable following the in vitro gastrointestinal test. The PNF isolated in this study demostrated an action against ovine and caprine gastrointestinal nematodes and are candidates for use in biological control of these organisms. Among these microorganisms, Candelabrella musiformis appears to be the most promising fungi for use as a biological control agent in Costa Rica. Rev. Biol. Trop. 59 (1): 37-52. Epub 2011 March 01.


El control biológico es en la actualidad una alternativa para el control de los nematodos gastrointestinales que desarrollaron resistencia a los principales grupos de antihelmínticos. Para el aislamiento e identificación de hongos nematófagos depredadores, se tomaron muestras de 51 fincas distribuidas entre todas las provincias de Costa Rica. La naturaleza de las muestras incluyó: suelos de diferentes sembradíos (papa, tomate, banano, plantas ornamentales, chayote y café), heces de animales (bovinos, ovinos, caprinos y equinos), suelo y hojarasca de bosques y plantas con signos de enfermedad causada por nematodos. Las muestras se procesaron mediante 3 técnicas diferentes para la extracción de hongos a partir del suelo: espolvoreado en placa, dilución de suelos y cámara húmeda. Veinticuatro cepas de hongos nematófagos fueron aisladas de 19 fincas; el 83.3% de éstos fueron aislados mediante las técnica de espolvoreado en placa. Los hongos fueron identificados como: Arthrobotrys oligospora (n=13), Candelabrella musiformis (n=9) y por primera vez se reporta el aislamiento de A. conoides (n=1) y A. dactyloides (n=1) en el país. Asimismo, se aislaron 16 cepas de hongos de los géneros Trichoderma (n=13), Beauveria (n=1), Clonostachys (n=1) y Lecanicillium (n=1). Adicionalmente se les midió el pH, el cual varió entre 5.2-9.9, ubicándose los HND dentro de un rango entre 5.6-7.5. Las cepas de HND fueron cultivadas en 4 medios diferentes para la producción de clamidosporas: papa dextrosa agar, harina de maíz, extracto de malta y agar papa-zanahoria. El 95.8% de las cepas aisladas produjeron clamidosporas, principalmente en el medio agar papa-zanahoria. De estas cepas, se escogieron las de mayor producción para ser sometidas a la prueba de digestibilidad in vitro. Un total de 14 cepas fueron sometidos a esta prueba, de las cuales el 42.9% resultaron viables; de éstas, las cepas de A. conoides y A. dactyloides no sobrevivieron a la prueba de digestibilidad in vitro. De los microorganismos aislados, Candelabrella musiformis se considera el más promisorio de los hongos como agente biológico en Costa Rica.


Subject(s)
Animals , Fungi/physiology , Goat Diseases/prevention & control , Nematoda/microbiology , Nematode Infections/veterinary , Pest Control, Biological/methods , Sheep Diseases/prevention & control , Costa Rica , Feces/microbiology , Fungi/isolation & purification , Goats , Goat Diseases/parasitology , Nematode Infections/prevention & control , Sheep , Soil Microbiology , Sheep Diseases/parasitology
20.
Bol. micol ; 25: 15-27, dic. 2010. tab, graf
Article in Spanish | LILACS | ID: lil-585723

ABSTRACT

Se evaluó la presencia de hongos endófitos en hojas de dos plantas medicinales, Acanthospermum australe y Pterocaulon alopecuroides, utilizadas entre otras cosas para tratar infecciones cutáneas. El muestreo se realizó en el entorno rural de dos ciudades del nordeste argentino. Los especimenes fueron recogidos por aborígenes de la zona conocedores de su distribución ambiental. Los hongos se aislaron mediante la técnica de Bisseger et al., 1994 y se identificaron empleando caracteristicas morfofisiológicas. Considerando las dos plantas, se encontraron 40 morfoespecies, donde los taxa más frecuentes en Acanthospermum australe fueron: Alternaria alternata, Aureobasidium pullulans, Fusarium oxysporum, F.solani, Myrothecium roridum, Phoma spp. y Sordaria fimícola, y en Pterocaulon alopecuroides fueron: Alternaria alternata, Aureobasidium pullulans, Cladosporium cladosporioides, Curvularia lunata, Fusarium proliferatum y Myrothecium roridum. Estos taxas considerados como generalistas (o de múltiples hospedadores), presentan según la literatura específica analizada, alta producción de metabolitos secundarios bioactivos con potenciales capacidades terapéuticas antimicrobianas.


The presence of endophytic fungi in leaves of two medicinal plants (Acanthospermum australe andPterocaulon alopecuroides) used mainly to treat skin infections, was evaluated. The sampling was performed in the rural area of two cities of northeast Argentina.The specimens were collected by the aboriginals who know the ®medicines¼. Fungi were isolated employing the Bisseger et al., 1994 technique and they were identifying by morpho fisiological characteristics. Regarding the two plant species, 40 morphospecies were found. The most frequent taxa in Acanthospermum australe were: Alternaria alternata, Aureobasidium pullulans, Fusarium oxysporum, F. solani, Myro-thecium roridum, Phoma sp. and Sordaria fimícola, and inPterocaulon alopecuroides were: Alternaria alternata, Aureobasidium pullulans, Cladosporium cladosporioides, Curvularia lunata, Fusarium proliferatum y Myrothecium roridum. These species considered generalistics (found in multiple hosts), presented in the analized literature a high production of bioactive secondary metabolites with eventual antimicrobial therapeutic properties.


Subject(s)
Fungi/isolation & purification , Fungi/classification , Fungi/growth & development , Fungi/physiology , Fungi/chemistry , Plants, Medicinal/microbiology , Skin Diseases, Infectious , Argentina
SELECTION OF CITATIONS
SEARCH DETAIL