Etiologia do declínio de mangostanzeiros no sul da Bahia

O declínio do mangostanzeiro (Garcinia mangostana L.) no litoral sul do Estado da Bahia é hoje o principal problema da cultura, sendo caracterizado por sintomas de murcha, amarelecimento, seca e queda de folhas. Este trabalho teve como objetivo acompanhar a evolução da sintomatologia da doença, isolar e identificar os potenciais patógenos causadores do declínio do mangostanzeiro. A doença começa com a necrose das radículas, a qual atinge as raízes secundárias, primárias e progride até à base do tronco que desenvolve lesões necróticas extensas. Os sintomas secundários são clorose, murcha e queda das folhas. Das amostras de tecidos lesionados de plantas doentes levadas ao laboratório, foram isolados e identificados os seguintes fungos: Lasiodiplodia theobromae, Lasiodiplodia parva, Mycoleptodiscus sp., Rhizopus sp., Stilbella sp., Trichoderma spp. e Aspergillus sp. Apenas L. theobromae e L. parva foram patogênicas a fragmentos de raízes e caules de mangostanzeiros in vitro e a mudas de mangostanzeiros em casa de vegetação, sendo o isolado da primeira espécie o mais virulento. A taxonomia do gênero Lasiodiplodia e algumas condições que influenciam no desenvolvimento da doença no campo foram analisadas.

Antifungal activity of compounds targeting the Hsp90-calcineurin pathway against various mould species.

OBJECTIVES: Invasive mould infections are associated with a high mortality rate and the emergence of MDR moulds is of particular concern. Calcineurin and its chaperone, the heat shock protein 90 (Hsp90), represent an important pathway for fungal virulence that can be targeted at different levels. We investigated the antifungal activity of compounds directly or indirectly targeting the Hsp90-calcineurin axis against different mould species. METHODS: The in vitro antifungal activity of the anticalcineurin drug FK506 (tacrolimus), the Hsp90 inhibitor geldanamycin, the lysine deacetylase inhibitor trichostatin A and the Hsp70 inhibitor pifithrin-μ was assessed by the standard broth dilution method against 62 clinical isolates of Aspergillus spp. and non-Aspergillus moulds (Mucoromycotina, Fusarium spp., Scedosporium spp., Purpureocillium/Paecilomyces spp. and Scopulariopsis spp.) RESULTS: FK506 had variable antifungal activity against different Aspergillus spp. and was particularly active against Mucor spp. Geldanamycin had moderate antifungal activity against Fusarium spp. and Paecilomyces variotii. Importantly, trichostatin A had good activity against the triazole-resistant Aspergillus ustus and the amphotericin B-resistant Aspergillus terreus as well as the MDR Scedosporium prolificans. Moreover, trichostatin A exhibited synergistic interactions with caspofungin against A. ustus and with geldanamycin against Rhizopus spp. for which none of the other agents showed activity. Pifithrin-μ exhibited little antifungal activity. CONCLUSIONS: Targeting the Hsp90-calcineurin axis at different levels resulted in distinct patterns of susceptibility among different fungal species. Lysine deacetylase inhibition may represent a promising novel antifungal strategy against emerging resistant moulds.

Conservação pós-colheita de mamão 'Sunrise Solo' com uso de quitosana

O mamão é um fruto de grande importância econômica, social e nutricional. No entanto, apresenta conservação limitada devido à deterioração pós-colheita e ao rápido amadurecimento. Portanto, o objetivo deste trabalho foi utilizar soluções de quitosana associadas ao glicerol como recobrimento de mamão papaia da cultivar 'Sunrise Solo' para manter a qualidade pós-colheita e prolongar sua vida útil. Os frutos foram lavados em água potável, higienizados em solução de hipoclorito de sódio a 200 mg L-1 por 10 minutos e secos à temperatura ambiente. Os tratamentos consistiram na imersão ou não (controle) dos frutos em cinco concentrações (0,25%; 0,50%; 0,75%; 1,0% e 1,25%) de quitosana. Decorrida a secagem natural do revestimento, os frutos foram armazenados a 28 ± 3 ºC e 65-70% UR. Foi utilizado um delineamento inteiramente casualisado, utilizando-se de seis concentrações de quitosana com oito repetições, totalizando 48 frutos. Ao atingir o ponto ótimo para o consumo, avaliaram-se o teor de ácido ascórbico, de sólidos solúveis, da acidez titulável, da firmeza, a perda de massa fresca, o desenvolvimento fúngico e a vida útil. A aplicação de quitosana em mamão 'Sunrise Solo' manteve a firmeza e os teores de sólidos solúveis, de acidez titulável e de ácido ascórbico dos frutos até o ponto considerado ótimo para o consumo, em termos de aparência. A concentração de 1% de quitosana manteve a qualidade e aumentou a vida útil dos frutos em quatro dias. A quitosana inibiu o crescimento de fungos dos gêneros Cladosporium, Aspergillus e Penicillium.

Nuevos fármacos inspirados en Annonáceas

Los metabolitos secundarios activos (MSA) juegan un papel importante en el descubrimiento de nuevos medicamentos. Moléculas naturales con esqueletos complejos, tales como las estatinas aisladas de Aspergillus terreus, o las acetogeninas específicas de la familia Annonaceae, no hubieran podido ser inventadas en ningún laboratorio. Los MSA aislados en Annonaceae, especialmente las acetogeninas y los alcaloides isoquinoleínicos, pueden ser considerados como fuente constante de inspiración para químicos, farmacólogos y para todos los investigadores interesados en el descubrimiento de una nueva familia de medicamentos.

Infecção pulmonar tripla em paciente gravemente imunocomprometido por AIDS: relato de caso

Os autores relatam um caso de paciente do sexo masculino, 38 anos de idade, motorista, soropositivo para HIV há oito anos, sem acompanhamento, com quadro de tosse produtiva com secreção acinzentada e episódios intermitentes de dispnéia há 15 dias. Informava dois episódios pregressos de tuberculose pulmonar (1983 e 2001) tratados. A radiografia de tórax evidenciou áreas de hipotransparência nodular e broncogramas aéreos bilateralmente. A tomografia computadorizada de tórax evidenciou vários achados inespecíficos, dentre eles áreas esparsas de consolidação, cavitação, bronquiectasia, opacidade em vidro fosco, espessamento intersticial e broncogramas aéreos. A lavagem broncoalveolar evidenciou numerosas hifas com raros septos bifurcados sugestivos de Aspergillus sp. e a cultura foi positiva para Nocardia sp. e Mycobacterium tuberculosis. Foi instituída terapia com anfotericina B, sulfametoxazol-trimetoprim e anti-retrovirais. Após 20 dias, recebeu alta sem queixas pulmonares. Decorridos 15 dias, retornou com diarréia, febre, disfagia e emagrecimento importante. Foi a óbito após cinco dias, por sepse estafilocócica.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation.

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

Comparing Etest and Broth Microdilution for Antifungal Susceptibility Testing of the Most-Relevant Pathogenic Molds.

Invasive mold infections are life-threatening diseases for which appropriate antifungal therapy is crucial. Their epidemiology is evolving, with the emergence of triazole-resistant Aspergillus spp. and multidrug-resistant non-Aspergillus molds. Despite the lack of interpretive criteria, antifungal susceptibility testing of molds may be useful in guiding antifungal therapy. The standard broth microdilution method (BMD) is demanding and requires expertise. We assessed the performance of a commercialized gradient diffusion method (Etest method) as an alternative to BMD. The MICs or minimal effective concentrations (MECs) of amphotericin B, voriconazole, posaconazole, caspofungin, and micafungin were assessed for 290 clinical isolates of the most representative pathogenic molds (154 Aspergillus and 136 non-Aspergillus isolates) with the BMD and Etest methods. Essential agreements (EAs) within ±2 dilutions of ≥90% between the two methods were considered acceptable. EAs for amphotericin B and voriconazole were >90% for most potentially susceptible species. For posaconazole, the correlation was acceptable for Mucoromycotina but Etest MIC values were consistently lower for Aspergillus spp. (EAs of <90%). Excellent EAs were found for echinocandins with highly susceptible (MECs of <0.015 μg/ml) or intrinsically resistant (MECs of >16 μg/ml) strains. However, MEC determinations lacked consistency between methods for strains exhibiting mid-range MECs for echinocandins. We concluded that the Etest method is an appropriate alternative to BMD for antifungal susceptibility testing of molds under specific circumstances, including testing with amphotericin B or triazoles for non-Aspergillus molds (Mucoromycotina and Fusarium spp.). Additional study of molecularly characterized triazole-resistant Aspergillus isolates is required to confirm the ability of the Etest method to detect voriconazole and posaconazole resistance among Aspergillus spp.

Co-produção de lipase e biossurfactante em estado sólido para utilização em biorremediação de óleos vegetais e hidrocarbonetos

Recently lipases have been increasing in prominence due to its wide industrial application. The lipase production can be influenced by different variables such as the producing microorganism, carbon sources, aeration and agitation conditions, inductor type and the geometry of the reactor. Biosurfactants are composites of surface active produced by microbial cells which reduce superficial and interfacial tensions. The objective of this study was to verify the influence of different process variables in the lipase production during a fermentative process. The results showed that the concomitant production of lipases and biosurfactant was possible in different cultivation conditions.

Biodegradação de fenol por uma nova linhagem de A spergillus sp. isolada de um solo contaminado do sul do Brasil

The main goal of this work was to study the biodegradation of phenol in batch mode by a filamentous fungus isolated from a contaminated site in Southern Brazil. A better performance was obtained by previous adaptation of the microorganism to the toxic chemical. A 2³ experimental design was proposed and it could be observed total phenol degradation in 72 h using 500 mg L-1 glucose, inoculum of 20% and agitation of 200 rpm, resulting a biodegradation rate of 3.76 mg L-1 h-1. In relation to phenol tolerance, Aspergillus sp. LEBM2 was able to consume up to 989 ± 15 mg L-1.

Produção, propriedades e aplicação de celulases na hidrólise de resíduos agroindustriais

Cellulases have been intensively studied in the past few years, due to the interests in biofuels production from lignocellulosic materials, since they permit maintaining mild conditions during the conversion process. These enzymes can be produced by a broad variety of naturally occurring microorganisms, such as from genera Aspergillus, Trichoderma, Penicillium and Humicola. Targeting the increasing of expression levels, molecular biology tools have been used for heterologous genes insertion in host cells, e. g., Pichia pastoris and Escherichia coli. Enzymes from fungal cellulolytic complex usually act best at pH between 4 and 5 under temperatures from 40 to 60 °C and can be used for either sequential (SHF) or simultaneous (SSF) hydrolysis together alcoholic fermentation. In this review, the main raw materials for production of cellulases are identified, as well as the state of art of enzymes' properties, production and main applications.

Enantioselective biotransformation of propranolol to the active metabolite 4-hydroxypropranolol by endophytic fungi

The enantioselective biotransformation of propranolol (Prop) by the endophytic fungi Phomopsis sp., Glomerella cingulata, Penicillium crustosum, Chaetomium globosum and Aspergillus fumigatus was investigated by studying the kinetics of the aromatic hydroxylation reaction with the formation of 4-hydroxypropranolol (4-OH-Prop). Both Prop enantiomers were consumed by the fungi in the biotransformation process, but the 4-hydroxylation reaction yielded preferentially (-)-(S)-4-OH-Prop. The quantity of metabolites biosynthesized varied slightly among the evaluated endophytic fungi. These results show that all investigated endophytic fungi could be used as biosynthetic tools in biotransformation processes to obtain the enantiomers of 4-OH-Prop.

Synthesis and antifungal activity of halogenated aromatic bis-γ-lactones analogous to avenaciolide

Here we describe the total syntheses and characterization by elemental analyses, infrared and NMR spectroscopy of three new compounds analogous to avenaciolide, a bis-γ-lactone isolated from Aspergillus avenaceus that possesses antifungal activity, where the octyl group of the natural product was replaced by aromatic groups containing chlorine and fluorine atoms. The effects of the avenaciolide, the novel compounds and their synthetic precursors on mycelia development and conidia germination of Colletotrichum gloeosporioides and Fusarium solani were evaluated in vitro. The title compounds were almost as active as avenaciolide. The absolute structures of the chlorinated analogs were determined by X-ray diffraction analysis.

Imobilização e caracterização de lacase e seu uso na biodegradação de efluentes de indústrias papeleiras

Laccase from Aspergillus sp was immobilized on glutaraldehyde-activated chitosan beads. A comparative study between free and immobilized laccase was conducted and the potential of the resulting immobilized derivative in the biodegradation of pulp and paper mill effluent was evaluated. The immobilized laccase is more resistant to various denaturing conditions, which allows for the reduction of 65% of the phenols (total and low molecular weight) and loss of 60% of total color in the effluent. These results show the potential of the immobilized laccase in the biodegradation of phenols, the chemical agents responsible for the high toxicity of the effluent generated in cellulose pulp industries.

CARBOXYLATION OF SILVER NANOPARTICLES FOR THE IMMOBILIZATION OF β-GALACTOSIDASE AND ITS EFFICACY IN GALACTO-OLIGOSACCHARIDES PRODUCTION

The present study investigated the carboxylation of silver nanoparticles (AgNPs) by 1:3 nitric acid-sulfuric acid mixtures for immobilizing Aspergillus oryzae β-galactosidase. Carboxylated AgNPs retained 93% enzyme upon immobilization and the enzyme did not leach out appreciably from the modified nanosupport in the presence of 100 mmol L-1 NaCl. Atomic force micrograph revealed the binding of β-galactosidase on the modified AgNPs. The optimal pH for soluble and carboxylated AgNPs adsorbed β-galactosidase (IβG) was observed at pH 4.5 while the optimal operating temperature was broadened from 50 ºC to 60 ºC for IβG. Michaelis constant, Km was increased two and a half fold for IβG while Vmax decreases slightly as compared to soluble enzyme. β-galactosidase immobilized on surface functionalized AgNPs retained 70% biocatalytic activity even at 4% galactose concentration as compared to enzyme in solution. Our study showed that IβG produces greater amount of galacto-oligosaccharides at higher temperatures (50 ºC and 60 ºC) from 0.1 mol L-1 lactose solution at pH 4.5 as compared to previous reports.

Toxicidade de filtrados fúngicos a meloidogyne incognita

Visando à obtenção de novas moléculas nematicidas, 18 filtrados de espécies fúngicas e extratos de sete micélios fúngicos foram estudados in vitro quanto aos efeitos sobre a eclosão, motilidade e mortalidade de juvenis do segundo estádio (J2) de Meloidogyne incognita. Filtrados fúngicos foram obtidos de culturas em meio Czapek. Metanol foi usado como solvente para obter extratos dos micélios fúngicos. Filtrados de Paecilomyces lilacinus, Fusarium moniliforme e Fusarium oxysporum reduziram a motilidade e eclosão, e aumentaram a mortalidade (P < 0,05) de J2 de M. incognita de forma semelhante à observada com Aldicarbe. Alguns filtrados fúngicos reduziram a motilidade, mas não causaram a morte de J2. Já os filtrados de Aspergillus flavus, Cylindrocarpon magnusianum, Fusarium solani e Mortierella sp. reduziram apenas a eclosão de J2. Não houve correlação entre a produção de metabólitos tóxicos e a quantidade de micélio fúngico produzido. No caso específico de P. lilacinus, observou-se que após o primeiro dia de cultivo o filtrado fúngico correspondente já apresentava toxidez contra M. incognita. Com o aumento do número de dias de cultivo foi elevado o efeito do filtrado sobre o nematóide, sendo que apenas após 13 dias a mortalidade de J2 alcançou o índice de 100%.