Diversidade de policetídeos produzidos por espécies de Penicillium isoladas de Melia azedarach e murraya paniculata

Eight compounds comprising four groups of polyketides, the xanthone fusarindin, the mixed peptide alkaloid-polyketide GKK1032, the anthraquinones crisophanol, citreoveridin and janthinone, and the azaphylones dihydrocitrinone, citrinin and citrinin H-1, were identified in Penicillium species isolated as endophytic fungi from Melia azedarach and Murraya paniculata. The antibacterial activity of the azaphylones was tested and showed that citrinin H-1 is more active than citrinin

Potential biosurfactant producing endophytic and epiphytic fungi, isolated from macrophytes in the Negro River in Manaus, Amazonas, Brazil

Endophytic and epiphytic fungi isolated from Eichhornia crassipes (Mart.) Solms and Cyperus ligularis L., macrophytes collected from oil-contaminated waters, were studied to assess their potential for producing biosurfactants; the most promising ones were identified by means of the rDNA region sequencing. In the selection, in the hydrocarbonate biodegradation activity, 2.6-indophenol (DCPIP) in oil-added Bushnell-Haas (BH) medium was the indicator used. The following tests were performed to ascertain the biosurfactant, bioemulsifier activity: emulsification measurement, drop-collapse, surface tension and production slope. Of the twenty fungi isolated, six promoted DCPIP discoloration. The isolate (S31) Phoma sp. showed emulsification of diesel (1.5 cm or 52%) and reduction of the surface tension of 51.03 mN/m water identified as Phoma sp. The other five fungi were identified as Rhizopus oryzae (S24), Fusarium sp. (S32, S33, S42, S46), presenting potential for biodegradation of hydrocarbons, as well. New studies on Phoma sp. (S31), including its cultivation in different carbon sources will be necessary to improve the production of secondary compounds involved in surface tension bioemulsification and reduction.Keywords: Bioremediation, bioemulsifiers, Eichhornia, Cyperus, oil, diese

ENZYME-PRODUCING FUNGI ASSOCIATED TO AQUATIC MACROPHYTES OF THE NEGRO RIVER, MANAUS

O ambiente amazônico se destaca por exuberante biodiversidade, principalmente, em relação aos micro-organismos como fungos e bactérias associados a diferentes espécies de plantas; nesse ambiente, a procura por enzimas produzidas por esses micro-organismos é de extrema importância, pois abre caminho para conhecer essa biodiversidade e transformá-la em potencial enzimático com várias finalidades. Fungos isolados de macrófitas aquáticas, encontradas no rio Negro, Manaus-AM foram selecionados por meio de diferentes testes enzimáticos. Nesta avaliação utilizaram-se diferentes protocolos para amilase, celulase, proteases, pectinase e lacase. A seleção dos isolados foi avaliada por meio de um índice enzimático representado por um halo ao redor das colônias, sendo considerado como parâmetro para todas as análises. Os métodos estatísticos multivariados aplicados foram: Análise de Componentes Principais (PCA) e Análise de Agupamento (AA). A identificação molecular das cepas foi realizada com o kit comercial Plant/Fungy DNA isolation (NorgenBiotekCorp), sendo identificados os seguintes fungos: Fusarium fugikuri, F. oxysporum (dois isolados), F. proliferatum, Phoma sp (dois isolados) Rhizopus orysae (dois isolados). Dentre os 8 isolados avaliados, todos produziram amilase (0,7 a 4,4 cm) e protease (1,9 a 4,4 cm), cinco produziram pectinase (1,8 a 2,9 cm) três produziram celulase (0,1 a 1,7 cm) e somente um isolado produziu lacase (1,04 cm). Por meio da análise multivariada foi possível verificar que os Fusarium spp. apresentaram maior similaridade quanto aos índices registrados. Esses resultados evidenciam o potencial desses micro-organismos em relação à produção de enzimas pelos fungos associados à macrófitas aquáticas encontradas no rio Negro em Manaus.Palavras-chaves: Fungos, enzimas, plantas aquáticas.The Amazonian environment stands out due to its exuberant biodiversity, speciously when it comes to microorganisms such as, fungi and bacteria associated to different plant species. In such an environment, the search for these microorganisms-producers of enzymes is of utter importance since it opens the way to learn more about this biodiversity so as to turn its enzymatic potential into various purposes. Fungi isolated from aquatic macrophytes found on the Negro river, were selected through enzymatic assays. The present assessment has utilized the protocols for amylase, cellulase, proteases, pectinase and laccase. The selection was evaluated by means of an enzymatic index, which represented a halo around the colony and was considered a parameter for all the analyses. The multivariate statistical methods applied were: Principle Component Analysis (PCA) and Cluster Analysis (AA). The molecular identification of the strains was performed with the commercial Plant / Fungi DNA isolation kit (Norgen Biotek Corp), and the following fungi were identified: Fusarium fugikuri, F. oxysporum, F. proliferatum, Phoma sp and Rhizopus orysae. Amongst the eight isolates assessed, every one produced amylase (0.7-4.4 cm) and protease (1.9-4.4 cm), however, five of them produced pectinase (1.8-2.9 cm), three cellulase (0.1-1.7 cm) and just one laccase (1.04 cm), as well. Through the multivariate analysis it was possible to verify that Fusarium spp., presented greater similarity to the recorded indexes. These results demonstrated the potential of these micro-organisms when it came to the production of enzymes by fungi associated to the aquatic macrophytes found on the Negro river in Manaus.Keywords: Fungy; enzymes; aquatic plants

Inibição do crescimento in vitro de Sclerotinia sclerotiorum, causador de mofo branco, por isolados de Trichoderma spp.

Sclerotinia sclerotiorum is a fungal pathogen that causes damages to many plants of economic interest, being responsible for root and stem rot, seedling wilt and damping-off, known as white mold. Trichoderma spp. are among the most studied fungi as biocontrol agents, being antagonistic to various phytopathogens in different cultures. This study aimed to verify the ability of Trichoderma spp. isolates as the efficiency in inhibiting the growth of S. sclerotiorum, the white mould causal agent. For the experiment, eight Trichoderma spp. isolates and one S. sclerotiorum isolate were used, obtained from tomato crop. The inhibition examination of Trichoderma spp. against the phytopathogen was performed by using the methodology of direct confrontation, with a scale ranging from one to seven and the measurement of the colonies diameter for the volatile metabolites production methodology. The design was completely randomized with ten repetitions. Most of Trichoderma isolates showed relative efficiency on the S. sclerotiorum inhibition; however the TM1 and TI4 showed more aggressiveness considering the direct confrontation and volatile metabolites production.Sclerotinia sclerotiorum é um patógeno que causa danos em muitas plantas de interesse econômico, sendo responsável pela podridão de raízes e colo, murcha e tombamento de plântulas, conhecido como mofo branco. Trichoderma spp. estão entre os fungos mais pesquisados atualmente, como agente de biocontrole, sendo antagonistas a vários fitopatógenos em diferentes culturas. O trabalho teve como objetivo verificar a capacidade de isolados de Trichoderma quanto à eficiência na inibição do crescimento de S. sclerotiorum. Para o experimento foram utilizados oito isolados de Trichoderma spp. e um isolado de S. sclerotiorum, obtido de cultura do tomate. A verificação da inibição dos isolados de Trichoderma spp. contra o fitopatógeno foi realizada utilizando-se a metodologia de confrontação direta, com uma escala de notas que variam de um a sete e a medida do diâmetro das colônias para a metodologia de produção de metabólitos voláteis. O delineamento foi inteiramente casualizado com dez repetições. A maioria dos isolados de Trichoderma spp. mostraram relativa eficiência na inibição de S. sclerotiorum, porém os isolados TM1 e TI4 apresentaram maior agressividade considerando a confrontação direta e produção de metabólitos voláteis

Potential of Bacterial Isolates from a Stream in Manaus-Amazon to Bioremediate Chromium-Contaminated Environments

Igarapé do Quarenta (IgQ), a stream located in the Manaus-AM, BR, has directly experienced the impacts of urban expansion over the last five decades, which contributed for its contamination. As an affluent of Rio Negro, IgQ also affects the water quality of this important river that bathes Manaus. However, the stress caused by the prolonged exposition to chemical agents may have selected microorganisms that exhibit great bioremediation potential. In the present study, bacteria isolated from four distinct sites of the IgQ were identified, and their potential to degrade hexavalent chromium (Cr(VI)) was investigated using the s-diphenylcarbazide method. Among the investigated isolates, 14 exhibited resistance against Cr(VI) at a concentration of 300 mg/L and eight isolates reduced over 50% (53.5–97.4%) chromium ratios after 72 h of incubation. Those isolates were identified by gene sequencing and classified in 10 genera (Acidovorax sp., Acinetobacter sp., Alicycliphilus sp., Bacillus sp., Comamonas sp., Enterobacter sp., Micrococcus sp., Proteus sp., Serratia sp., and Vagococcus sp.). Under control conditions, the isolate of Vagococcus sp. genus, in only 24 h of incubation, reduced 96.8% of the rate of Cr(VI) added to the culture medium at the concentration of 10 mg/L. Obtained results indicate that the Vagococcus sp. exhibits a great potential to be used in the bioremediation of areas contaminated with chromium. The mechanisms of action of microorganisms should be investigated for more specific applications in the decontamination of effluents and direct use of its by-products to bioremediate polluted environments. © 2018, The Author(s)

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications