Marcos José Salgado Vital

Diversity and physiological characterization of D-xylose-fermenting yeasts isolated from the Brazilian Amazonian Forest.

Background This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. Methodology/Principal Findings A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L) culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g) and productivities (0.62 g/L·h to 0.75 g/L·h). Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g), with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g) and productivity (0.2 g/L·h), while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. Conclusions/Significance This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates.

Mycocinogenic yeasts isolated from Amazon soils of the Maracá Ecological Station, Roraima-Brazil

The 240 yeasts isolated from soils of the Maraca Ecological Station in the Brazilian Amazon were identified and screened for mycocin production. These strains included 82% of ascomycetous and 18% basidiomicetous affinities and the prevalent species were Candida etchellsii, Candida famata, Candida robusta, Candida rugosa, Candida valida, Debaryomyces hansenii, Cryptococcus albidus, Cryptococcus laurentii, Rhodotorula glutinis, Rhodotorula minuta and Rhodotorula mucilaginosa. Mycocins able to kill some yeasts were produced by 6 strains identified as Issatchenkia sp., Saccharomyces exiguus?, Williopsis saturnus, var. subsufficiens, and 3 W. saturnus according to 26S rDNA D1/D2 region sequence and phenotypic data.

Antibacterial and antifungal activity of extracts and exudates of the Amazonian medicinal tree Himatanthus articulatus (Vahl) Woodson (common name: sucuba)

Himatanthus articulatus (Vahl) Woodson is a tree found in the northern Amazon savannahs (common name: sucuba) that is used in local Amerindian medicine. Leaf, bark and branch wood methanol extracts, sequentially obtained hexane, ethyl acetate and methanol extracts and latex were evaluated for antifungal and antibacterial activities against American Type Culture Collection (ATCC) and local clinical strains using the disc diffusion method. Methanol extracts and latex inhibited Candida albicans, leaf methanol extracts inhibited Staphylococcus aureus and Bacillus subtilis and bark methanol extracts inhibited B. subtilis. Active extracts inhibited the ATCC and clinical strains. Polar antifungal and antibacterial principles in latex and extracts are thought to be responsible for the inhibition.

The yeast community and mycocin producers of guava fruit in Rio de Janeiro, Brazil

Two hundred and fifty-seven strains be- longing to 28 ascomycetous yeast species were isolat- ed from fallen guava fruit (Psidium guajava) from an Atlantic forest and a rural area in Rio de Janeiro, Brazil. The most frequent species were Kloeckera af- ricana, K. apis, Pichia kluyveri and P membranifa- ciens. Issatchenkia sp A and Issatchenkia sp B, two probable new species were also isolated in a high fre- quency at the forest site. Mycocinogenic yeasts (killer yeasts) with narrow killing spectra were represented by Candida diddensiae-like, C. diversa, C. stellata, I. terricola, K. africana, K. lindneri, P kluyveri, P mem- branifaciens and Torulaspora delbrueckii. The yeasts

Candida amazonensis sp. nov., an ascomycetous yeast isolated from rotting wood in the Amazonian forest.

Five strains of a novel yeast species were isolated from rotting wood samples collected in an Amazonian forest site in the state of Roraima, northern Brazil. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the Scheffersomyces clade and is related to Candida coipomoensis, Candida lignicola and Candida queiroziae. The novel species Candida amazonensis sp. nov. is proposed to accommodate these isolates. The type strain of C. amazonensis sp. nov. is UFMG-HMD-26.3(T) ( = CBS 12363(T) = NRRL Y-48762(T)).

Cyberlindnera xylosilytica sp. nov., a xylitol-producing yeast species isolated from lignocellulosic materials.

Independent surveys of yeasts associated with lignocellulosic-related materials led to the discovery of a novel yeast species belonging to the Cyberlindnera clade (Saccharomycotina, Ascomycota). Analysis of the sequences of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene showed that this species is related to C. japonica, C. maesa and C. easanensis. Six isolates were obtained from different sources, including rotting wood, tree bark and sugar cane filter cake in Brazil, frass from white oak in the USA and decayed leaf in Taiwan. A novel species is suggested to accommodate these isolates, for which the name C. xylosilytica sp. nov. is proposed. The type strain of C. xylosilytica sp. nov. is NRRL YB-2097(T) ( = CBS 13984(T) = UFMG-CM-Y347(T)) and the allotype is UFMG-CM-Y409 ( = CBS 14083). The novel species is heterothallic and complementary mating types are represented by the type and allotype strains. The MycoBank number is MB 811428.

Ocorrência de fungos endofíticos "dark septate" em raízes de Oryza glumaepatula na Amazônia

The objective of this work was to assess the occurrence of dark septate endophyte fungi (DSEF) in Oryza glumaepatula in Amazonia, and its in vitro colonization capacity. Oryza glumaepatula plants were collected in forest and cerrado areas of the Roraima state, Brazil. The roots were prepared to observe septate melanized hyphas and microesclerotia. The isolation of fungi was done in agar malte medium. Dark septate endophyte fungi were observed in plants from both environments, with higher colonization on those collected in the forest. One isolate was able to colonize the original host and also Oryza sativa plants, exhibiting typical DSEF structures in rice healthy plants.

Chemical composition, ethnopharmacology and biological activity of Geissospermum Allemão species (Apocynaceae Juss.)

The chemistry and pharmacology literature on Geissospermum is surveyed. Pau-pereira or pao pereira ( G. laeve (Vell.) Miers; G. vellosii Fr. All. is a synonym) is the best known of approximately six Geissospermum species. Pau-pereira bark is mainly used for its bitterness and medicinal properties. It is used to treat pain, liver ailments, fevers, appetite loss, indigestion, dizziness, constipation and malaria, among other ailments. The other Geissospermum species have similar traditional uses. Pau-pereira provides monoterpenoid indole alkaloid rich extracts and fractions and pure isolates that comprise formulations used in clinical practice for the treatment of prostate cancer (flavopereirine) and HIV-AIDS (flavopereirine). Also, G. vellosii extracts exhibit pronounced antinociceptive activity in animals (perhaps due to 12-methoxy-1-methylaspidospermine). Induced amnesia in mice is reduced by pau-pereira extracts and geissospermine which also have anticholinesterase activity and potential application against Alzheimer´s Disease. G. argenteum Woodson extracts exhibit in vitro antibacterial activity. Extracts of three Geissospermum species and isolated alkaloids aspidocarpine, flavopereirine, and geissolosimine strongly inhibit the human malaria parasite Plasmodium falciparum Welch in vitro. Two Geissospermum species inhibit Plasmodium yoelii in rodents and exhibit toxicity. Geissospermum extracts and alkaloids inhibit P. falciparum , Leishmania infantum Nicolle and Trypanosoma cruzi Chagas and deserve further study as therapeutic agents.

Cyberlindnera tropicalis f.a., sp. nov., a novel yeast isolated from tropical regions

Two yeast strains, DMKU-WBBC14 and UFMG-CM-Y3283, were isolated from soil in Samutprakarn province in the central part of Thailand and from rotting wood in an Amazonian forest site in the Roraima State in Brazil, respectively. The two strains showed identical sequences of the D1/D2 domain of the large subunit (LSU) rRNA gene and different sequences by three nucleotide substitutions of the internal transcribed spacer (ITS) region. Therefore, these two strains represented a single species which was most closely related to Cyberlindnera mengyuniae CBS 10845T. The nucleotide sequence differences between the two strains of the novel species and the type strain Cyberlindnera mengyuniae CBS 10845T were 10 substitutions in the D1/D2 region of the LSU rRNA gene and 46 substitutions in the ITS region. DMKU-WBBC14 and UFMG-CM-Y3283 differed in growth temperature profiles. Moreover, they also exhibited different carbon assimilation profiles and growth temperature profiles from the type strain of Cyberlindnera mengyuniae, CBS 10845T. The name Cyberlindnera tropicalis f.a., sp. nov. is proposed. The type strain is DMKU-WBBC14T (=CBS 14558T=TBRC 6562T). The Mycobank number is MB 819722.

Scheffersomyces stambukii f.a., sp. nov., a d-xylose-fermenting species isolated from rotting wood

Two isolates representing a new species of Scheffersomyces were isolated from rotting wood samples collected in an Amazonian forest ecosystem in Brazil. Analysis of the sequences of the D1/D2 domains showed that this new species is phylogenetically related to Scheffersomyces NYMU 15730, a species without a formal description, and the two are in an early emerging position with respect to the xylose-fermenting subclade containing Scheffersomyces titanus and Scheffersomyces stipitis. Phylogenomic analyses using 474 orthologous genes placed the new species in an intermediary position between Scheffersomyces species and the larger genus Spathaspora and the Candida albicans/Lodderomyces clade. The novel species, Scheffersomyces stambukii f.a., sp. nov., is proposed to accommodate these isolates. The type strain of Scheffersomyces stambukii sp. nov. is UFMG-CM-Y427T (=CBS 14217T). The MycoBank number is MB 824093. In addition, we studied the xylose metabolism of this new species.