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Made available in DSpace on 2020-12-12T02:20:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 BACKGROUND: Sugarcane bagasse is a heterogeneous and organized material that needs a pretreatment to access the polysaccharides (cellulose and xylan). The particle size of a non-milled bagasse can influence the xylan and xylose solubilization, as well as the enzymatic hydrolysis of the pretreated material. Using bagasse selected on 16-, 30-, 40- and 50-mesh sieves: xylan solubilization was performed with hydrogen peroxide; xylose was solubilized with diluted sulfuric acid; and enzymatic hydrolysis was conducted for glucose yield evaluation. RESULTS: The xylose solubilized by acid pretreatment resulted in a maximum of 6.59 g L−1 with no influence of particle size. The solubilized xylan showed linear correlation with a variation of 36.18% (16-mesh bagasse) to 71.43% (

Insects interact with a wide variety of yeasts, often providing a suitable substrate for their growth. Some yeast-insect interactions are tractable models for understanding the relationships between the symbionts. Attine ants are prominent insects in the Neotropics and have performed an ancient fungiculture of mutualistic basidiomycete fungi for more than 55-65 million years. Yeasts gain access to this sophisticated mutualism, prompting diversity, ecological, and biotechnological studies in this environment. We review half a century research in this field, surveying for recurrent yeast taxa and their putative ecological roles in this environment. We found that previous studies mainly covered the yeast diversity from a small fraction of attine ants, being Saccharomycetales, Tremellales, and Trichosporonales as the most frequent yeast or yeast-like orders found. Apiotrichum, Aureobasidium, Candida, Cutaneotrichosporon, Debaryomyces, Meyerozyma, Papiliotrema, Rhodotorula, Trichomonascus, and Trichosporon are the most frequent recovered genera. On the other hand, studies of yeasts' ecological roles on attine ant-fungus mutualism only tapped the tip of the iceberg. Previous established hypotheses in the literature cover the production of lignocellulosic enzymes, chemical detoxification, and fungus garden protection. Some of these roles have parallels in biotechnological processes. In conclusion, the attine ant environment has a hidden potential for studying yeast biodiversity, ecology, and biotechnology, which has been particularly unexplored considering the vast diversity of fungus-growing ants.

Made available in DSpace on 2019-10-04T12:35:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this study, sugarcane bagasse hemicellulosic hydrolisate was evaluated as carbon source in biosurfactant production by yeasts. 27 yeasts were screened in culture media based on commercial xylose, non-detoxified and detoxified sugarcane bagasse hydrolysate to select potential strains for BS production with emulsifying and tensoactive properties. Cutaneotrichosporon mucoides UFMG-CM-Y6148 cultured in medium based on detoxified hydrolysate was the best producer of biosurfactant with a volumetric productivity of 0.167 g.L-1. h(-1) and highlighted emulsifying properties in kerose as emulsification index higher than 50% and an emulsifying activity of 1.0 EU. mL(-1), and its effectiveness was demonstrated over a wide range of temperature, pH and salt con- centration. The chromatography and spectrometry analysis demonstrated that the BS produced by C. mucoides UFMG-CM-Y6148 was a sophorolipid. The results obtained in this study demonstrated the successful sustainable prodution of biosurfactant by yeasts in media with hemicellulosic hydrolysate and the viability of these products for biorefineries. Univ Sao Paulo, Engn Sch Lorena, Dept Biotechnol, BR-12602810 Sao Paulo, Brazil Paulista State Univ Campus Rio Claro, Inst Biosci, Dept Biochem & Microbiol, BR-13506900 Rio Claro, Brazil Univ Fed Minas Gerais, Inst Biol Sci, Dept Microbiol, BR-31270901 Belo Horizonte, MG, Brazil Paulista State Univ Campus Rio Claro, Inst Biosci, Dept Biochem & Microbiol, BR-13506900 Rio Claro, Brazil FAPESP: 2015/06238-4 FAPESP: 2016/14852-7 FAPESP: 2016/10636-8

Made available in DSpace on 2021-06-25T10:53:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 Sugarcane biomasses, such as bagasse and straw, are abundant and represent renewable sources for the production of molecules of economic interest, such as xylan. However, the solubilization methods for this macromolecule face the material recalcitrance and, consequently, need a higher amount of chemicals. This study brings as the fractioning of biomass for xylan extraction, aiming to verify how the recalcitrance of different segments of the plant may interfere with the process of xylan solubilization. Hydrogen peroxide was applied in the xylan solubilization starting from the bagasse, moving on to the leaf and stem, which was fractionated in internode, node, and external fraction (which contains epidermis). The solubilized xylan was evaluated as a substrate for the determination of the enzymatic activity of xylanase. The solubilized xylan was monitored for its solubility and for impurities, such as salt and residual lignin content. The results of xylan solubilization with 6 % of hydrogen peroxide were 86.28, 65.39, 76.78, 97.95, 96.48 %, successively for bagasse, internode, node, external fraction, and leaf. With the application of 3% peroxide, the yield decreased to lower than 30 %, except for the internode and the leaf, which showed 47.85 and 46.15 %, respectively. The RMN analysis suggested similarity among the xylan samples solubilized from the different sugarcane anatomic fractions. The highest enzymatic activities were found with the solubilized xylan, instead of the commercial one. The solubility and purity tests (low salt content) indicate that the solubilized xylan presented characteristics similar to commercial xylan or even better than it. Institute for Research in Bioenergy (IPBEN) São Paulo State University (UNESP) Biochemistry and Microbiology Department São Paulo State University (UNESP) Institute for Research in Bioenergy (IPBEN) São Paulo State University (UNESP) Biochemistry and Microbiology Department São Paulo State University (UNESP)

Made available in DSpace on 2021-06-25T10:59:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Environmental pollution with alkylbenzene hydrocarbons such as toluene is a recurring phenomenon. Their toxicity and harmful effect on people and the environment drive the search for sustainable removal techniques such as bioremediation, which is based on the microbial metabolism of xenobiotic compounds. Melanized fungi present extremophilic characteristics, which allow their survival in inhospitable habitats such as those contaminated with hydrocarbons. Screening methodologies for testing the microbial assimilation of volatile organic compounds (VOC) are scarce despite their importance for the bioremediation of hydrocarbon associated areas. In this study, 200 strains of melanized fungi were isolated from four different hydrocarbon-related environments by using selective methods, and their biodiversity was assessed by molecular and ecological analyses. Seventeen genera and 27 species from three main orders, namely Chaetothyriales, Cladosporiales, and Pleosporales, were identified. The ecological analysis showed a particular species distribution according to their original substrate. The isolated strains were also screened for their toluene assimilation potential using a simple and inexpensive methodology based on miniaturized incubations under controlled atmospheres. The biomass produced by the 200 strains with toluene as the sole carbon source was compared against positive and negative controls, with glucose and with only mineral medium, respectively. Nineteen strains were selected as the most promising for further investigation on the biodegradation of alkylbenzenes. Center for the Study of Social Insects São Paulo State University (UNESP) GIRO Institute of Agrifood Research and Technology (IRTA), Torre Marimon Basic Pathology Department Federal University of Paraná (UFPR) Division of Microbial Resources CPQBA University of Campinas (Unicamp) Center for the Study of Social Insects São Paulo State University (UNESP) CAPES: 2013/01556-2 CNPq: 2013/01556-2 FAPESP: 2013/01556-2 CNPq: 312811/2018-7.

Made available in DSpace on 2021-06-25T10:56:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The leaf-cutter ant Acromyrmex balzani is responsible for causing important losses in reforestation areas, crops, and pastures, and is frequently found in the Brazilian savanna (Cerrado). So far, there is no information regarding the yeast communities that occur in their nests. Here, we evaluated the diversity, composition, and structure of yeast communities in both fungus gardens (FG) and external refuse dump (RD) of this ant species (Palmas, Tocantins, northern Brazil). A total of 720 yeasts were isolated, comprising 52 species distributed in 29 genera. The RDs have significantly richer and more diverse yeast communities than the fungus gardens, regardless of the season and the level of preservation in the area. The isolates produced a wide range of carbon polymer-degrading enzymes and were able to assimilate carbon-sources present in plant materials. We observed a different proportion of enzyme-producers and carbon-assimilation found in external refuse dump and fungus gardens from preserved and disturbed areas, suggesting that this interaction may vary depending on the environmental conditions. A. balzani nests in the savanna biome are a hotspot of yeast species with ecological, clinical, and biotechnological implications. Centre for the Study of Social Insects São Paulo State University (UNESP) Laboratory of Environmental Microbiology and Biotechnology Federal University of Tocantins (UFT) Department of Pharmaceutical Science School of Pharmaceutical Sciences of Ribeirão Preto University of São Paulo Department of Biology Faculty of Philosophy Sciences and Letters of Ribeirão Preto University of São Paulo Centre for the Study of Social Insects São Paulo State University (UNESP)

The leaf-cutter ant Acromyrmex balzani is responsible for causing important losses in reforestation areas, crops, and pastures, and is frequently found in the Brazilian savanna (Cerrado). So far, there is no information regarding the yeast communities that occur in their nests. Here, we evaluated the diversity, composition, and structure of yeast communities in both fungus gardens (FG) and external refuse dump (RD) of this ant species (Palmas, Tocantins, northern Brazil). A total of 720 yeasts were isolated, comprising 52 species distributed in 29 genera. The RDs have significantly richer and more diverse yeast communities than the fungus gardens, regardless of the season and the level of preservation in the area. The isolates produced a wide range of carbon polymer-degrading enzymes and were able to assimilate carbon-sources present in plant materials. We observed a different proportion of enzyme-producers and carbon-assimilation found in external refuse dump and fungus gardens from preserved and disturbed areas, suggesting that this interaction may vary depending on the environmental conditions. A. balzani nests in the savanna biome are a hotspot of yeast species with ecological, clinical, and biotechnological implications.

Made available in DSpace on 2020-12-12T02:02:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The lignocellulosic biomass, such as provided by the sugarcane, is an abundant source of raw materials for energy production. Milling and pretreatments can be employed to alter the structure of the materials, remove lignin, and hemicellulose. This pretreatment effect exposes the cellulose and raises its accessibility, which is one of the most important properties to ensure enzymatic digestibility. However, the biomass generated from the sugarcane has different physicochemical characteristics, giving different responses to the pretreatments. In this context, this study aimed to verify the effects of lignin and hemicellulose removal from the sugarcane biomass (external fraction, node, internode, and leaf) on cellulose accessibility. Each fraction was pretreated with acid (5, 10, and 20% w/w, at 121 °C/30 min), alkali (5, 10, 20, and 30% NaOH w/w) and oxidative (0.5, 1, 2, and 3 h charged with 30% sodium chlorite). Accessibility was determined by dye adsorption of Direct Orange (external specific surface) and Direct Blue (internal specific surface). Enzymatic hydrolysis was used to verify the effects of pretreatments and cellulose accessibility on the glucose yield. Delignification by sodium chlorite (oxidative) resulted in lignin removal, with almost complete removal from leaf samples. Accessibility determined indicated that pretreatments that are more aggressive improved cellulose accessibility. The less recalcitrant fraction, the internode, showed 1333.3 mg/g of Direct Orange adsorbed and 746.3 mg/g of Direct Blue. Glucose yield during enzymatic hydrolysis improved with higher cellulose accessibility. Lignin and xylan removal (down to 10% and 1%, respectively) resulted in higher glucose yield, with delignified internode samples showing almost complete cellulose conversion. Hemicellulose and lignin removal by the pretreatments directly influenced cellulose accessibility, resulting in better enzymatic hydrolysis across all fractions. This study successfully showed that lignin and hemicellulose removal of 15% and 10%, respectively, resulting in at least 60% of glucose yield, reaching desired accessibility levels based on dye adsorption of 2079.6 mg/g. Bioenergy Research Institute (IPBEN) Universidade Estadual Paulista (UNESP) Biochemistry and Microbiology Department Universidade Estadual Paulista (UNESP) Bioenergy Research Institute (IPBEN) Universidade Estadual Paulista (UNESP) Biochemistry and Microbiology Department Universidade Estadual Paulista (UNESP) CNPq: 401900/2016-9

Made available in DSpace on 2020-12-12T02:14:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-07 Sugarcane bagasse is a recalcitrance lignocellulosic material with difficult to structure disorganize and it has low cellulose accessibility, negatively influencing the enzymatic saccharification. This study identified the minor particle size that resulted in the efficient diluted acid pretreatment (10 % m/m, 121 °C/30 min) of sugarcane bagasse and a more recalcitrant material, that is external fraction (2 to 3 mm from the extremity, containing epidermis). Particle sizes were obtained by sieving sugarcane bagasse at 16 (1 mm), 24 (0.710 mm), 35 (0.425 mm), 60 (0.250 mm) and

Lignocellulosic biomass is one of the most abundant raw materials in the world, and it is mainly composed of carbohydrate polymers (cellulose and hemicellulose) and lignin. Its applications vary from the production of pulp and paper, to the most recent plant-based bioethanol production, which has challenge due to low hydrolysis conversion rates by the inherit recalcitrance of biomass. The biomass is naturally resistant due the high complexity in the component organization and interaction in the cell wall. The application of pretreatment technologies is one of the most used strategies to overcome biomass recalcitrance. These techniques often require a catalyst to modify the lignocellulosic structure which can be acids, alkaline compounds, ionic solutions, organic solvents, and even pressurized steam among others. The type of catalyst dictates the name of the pretreatment involved. This work presents an overview of these strategies, along with some recent contributions from the scientific community to improve biomass conversion technologies. The discussion is focused on the key factors related to the recalcitrance and conversion process, as well as the composition and physicochemical properties.

Made available in DSpace on 2018-12-11T17:17:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-05-01 Lignocellulosic biomasses such as banana pseudostem are attractive cellulose sources for bioenergy production, and for the use in biorefinery processes. However, pretreatment of lignocellulosic material is required to remove hemicellulose and lignin, while increasing cellulose accessibility to enzymatic hydrolysis (i.e., decreasing biomass recalcitrance). The effect of different concentrations of acid (H2SO4), alkaline (NaOH) and peroxide (H2O2) pretreatments on the chemical composition, cellulose accessibility, and enzymatic digestibility of banana pseudostem were studied. The water insoluble solids (WIS) recovery was low (∼30%) for the severe pretreatment conditions applied, indicating high material solubilization. Acid pretreatment completely removed the hemicellulose content, whereas alkaline and peroxide pretreatments reduced its amount to 4.38 and 8.68%, respectively. In contrast, the lignin content increased (from 17.26 to 39.99%) after severe acid pretreatment, while alkaline and peroxide pretreatments reduced the lignin content to 7.65% and 7.17%, respectively. In line with hemicellulose and lignin removal, the cellulose content increased from 60.84 to 75.48 and 74.37%, respectively for alkaline and peroxide pretreatments, with no alteration for acid. Dye adsorption assays showed that alkaline and acid pretreatments resulted in high internal and external specific surface areas – indicative of high cellulose accessibility – when compared with peroxide pretreatments. Overall, alkaline and acid pretreatments resulted in the highest glucose yields from enzymatic hydrolysis of banana pseudostem, compared with peroxide pretreatment. In conclusion, concentrations of each pretreatment that led to the highest glucose yields was identified, confirming that the banana pseudostem is a great source of fermentable sugars, with high potential for biofuel production. Bioenergy Research Institute (IPBEN) Universidade Estadual Paulista (UNESP) Laboratory of Microscopy Applied to Life Science – Lamav National Institute of Metrology Quality and Technology – Inmetro Center for the Study of Social Insects (CEIS) Universidade Estadual Paulista (UNESP) Laboratory of Cellular Ultrastructure Hertha Meyer Federal University of Rio de Janeiro – UFRJ Bioenergy Research Institute (IPBEN) Universidade Estadual Paulista (UNESP) Center for the Study of Social Insects (CEIS) Universidade Estadual Paulista (UNESP)

Leafcutter ants propagate co-evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite-marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade-A and Clade-B). The dominant and widespread Clade-A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade-A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade-B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade-A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade-B fungi occur only in South America. Diversity of Clade-A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov-Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot-specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus-growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars.

Made available in DSpace on 2018-12-11T17:15:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-01 The ability of twenty-three yeast strains isolated from decayed wood and the fungus garden of attine ants to produce hemi- and cellulolytic hydrolases in a chemically defined medium was acessed. Xylanase, β-glucosidase and cellulase activities were found in yeasts strains in the genera of Cryptococcus, Trichosporon, Debaryomyces and Pichia. Among the isolated microorganisms, two strains of Trichosporon laibachii MG270406-1A14 strain showed higher cellulase titers. Several biochemical and physiological parameters were investigated for optimum cellulase production under submerged fermentation. Enzyme induction was also examined using different carbon and nitrogen sources. Cellobiose and ammonium sulphate were found best carbon (C) and nitrogen (N) sources to enhance carboxymethylcellulase production. A 22- factorial design with center points was developed to optimize enzyme production, and data analysed by the response surface method. Maximal enzyme titres (0.3 U mL-1) occurred at initial pH 6.0, C/N ratio 9.0 and 5 days. Department of Biotechnology School of Engineering of Lorena University of São Paulo Center for Mineral Technology Department of Biochemistry and Chemical Technology Institute of Chemistry São Paulo State University-UNESP Department of Biochemistry and Microbiology Biosciences Institute of Rio Claro UNESP Department of Biochemistry and Chemical Technology Institute of Chemistry São Paulo State University-UNESP Department of Biochemistry and Microbiology Biosciences Institute of Rio Claro UNESP

Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains studied revealed that they cluster in two main lineages. The first was associated with the genus Xenopenidiella whereas the other represented two ant-isolated lineages sister to the taxa Penidiella aggregata and P. drakensbergensis, which are allocated to the new genus Penidiellomyces. The genus Penidiella is limited to the lineage containing P. columbiana, which is not congeneric with Penidiellomyces or Penidiellopsis, nor with Simplicidiella, a novel genus introduced here to accommodate a strain isolated from ants. For species level analysis, the final 26 aligned sequences of the ITS (498 characters), cmdA (389 characters), tef1 (342 characters) and tub2 (446 characters) gene regions lead to the introduction of six new species in Xenopenidiella, and one in respectively Penidiellopsis and Simplicidiella. The species described in this study were distinguished by the combination of morphological and phylogenetic data. Novelties on the integument of leaf-cutting ants from Brazil include: Penidiellopsis ramosus, Xenopenidiella clavata, X. formica, X. inflata, X. laevigata, X. nigrescens, X. tarda spp. nov., and Simplicidiella nigra gen. & sp. nov. Beta-tubulin is recommended as primary barcode for the distinction of species in Penidiellopsis, whereas ITS was sufficient to distinguish species of Xenopenidiella.

Made available in DSpace on 2018-12-11T17:03:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 The relationship of attine ants with their mutualistic fungus and other microorganisms has been studied during the last two centuries. However, previous studies about the diversity of fungi in the ants’ microenvironment are based mostly on culture-dependent approaches, lacking a broad characterization of the fungal ant-associated community. Here, we analysed the fungal diversity found on the integument of Atta capiguara and Atta laevigata alate ants using 454 pyrosequencing. We obtained 35,453 ITS reads grouped into 99 molecular operational taxonomic units (MOTUs). Data analysis revealed that A. capiguara drones had the highest diversity of MOTUs. Besides the occurrence of several uncultured fungi, the mycobiota analysis revealed that the most abundant taxa were the Cladosporium-complex, Cryptococcus laurentii and Epicoccum sp. Taxa in the genus Cladosporium were predominant in all samples, comprising 67.9 % of all reads. The remarkable presence of the genus Cladosporium on the integument of leaf-cutting ants alates from distinct ant species suggests that this fungus is favored in this microenvironment. Center for the Study of Social Insects UNESP - São Paulo State University, Avenida 24-A, n. 1515, Bela Vista Department of Biochemistry and Microbiology UNESP - São Paulo State University Department of Plant Protection UNESP - São Paulo State University Center for the Study of Social Insects UNESP - São Paulo State University, Avenida 24-A, n. 1515, Bela Vista Department of Biochemistry and Microbiology UNESP - São Paulo State University Department of Plant Protection UNESP - São Paulo State University

Made available in DSpace on 2018-12-11T17:04:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-01 A novel ascomycetous yeast species in the genus Wickerhamomyces was isolated from the fungus garden of an attine ant nest, Acromyrmex lundii (Hymenoptera: Formicidae), from Santa Fe province, Argentina. Pairwise sequence alignment of D1/D2 sequences in the GenBank (http://www.ncbi.nlm.nih.gov) database revealed that the novel species is related most closely to Wickerhamomyces subpelliculosus, Wickerhamomyces linferdii, Wickerhamomyces anomalus, Wickerhamomyces siamensis and Wickerhamomyces ciferrii with 96% similarity to the first four. The species name Wickerhamomyces spegazzinii sp. nov. is proposed to accommodate this novel strain, which differs from the above species in melibiose, 5-keto-D-gluconate, succinate, and DL-lactate assimilation among others. The type strain is JLU025T (=CBS 12756T=CBMAI 1619T). Instituto de Biociêencias UNESP – Univ Estadual Paulista SP. Centro de Estudos de Insetos Sociais, Campus de Rio Claro Instituto de Biociêencias UNESP – Univ Estadual Paulista SP. Centro de Estudos de Insetos Sociais, Campus de Rio Claro

Made available in DSpace on 2018-12-11T17:02:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-01 Fungus gardens of leaf-cutting ants harbor diverse alien fungi in addition to their fungal cultivar. Previous work suggested that alien microorganisms are likely derived from the substrata foraged by ant workers and incorporated into the fungus gardens. To test this hypothesis, we sampled 1014 garden fragments from 16 field colonies of Atta sexdens rubropilosa (a dicot-cutting ant) and Atta capiguara (a grass-cutting ant) in Brazil. From a total of 615 fungal isolates recovered, we observed similar diversity of fungi between colonies of both ant species. However, fungal communities differed in composition of taxa between ant colonies. Trichoderma spirale, Trichosporon chiarellii and Penicillium citrinum were prevalent accounting for 18.5%, 12.2% and 11.7% of the total isolates, respectively. As expected, fungal communities clustered in two major groups supporting the hypothesis that plant substratum has an impact on the composition of the alien fungi found in leaf-cutting ant gardens. UNESP - Univ Estadual Paulista Department of Biochemistry and Microbiology UNESP - Univ Estadual Paulista Department of Vegetal Protection UNESP - Univ Estadual Paulista Center for the Study of Social Insects UNESP - Univ Estadual Paulista Department of Biochemistry and Microbiology UNESP - Univ Estadual Paulista Department of Vegetal Protection UNESP - Univ Estadual Paulista Center for the Study of Social Insects

Made available in DSpace on 2020-12-12T02:23:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Occasionally, the symbiosis of the fungus-growing ants is threatened by ascomycetous fungi mainly by species in the genus Escovopsis. GC-MS analyses were conducted to investigate the volatile organic compounds (VOCs) produced by Escovopsis and the mutualistic Leucocoprinus gongylophorus during dual-culture. In dual-culture Escovopsis' development was faster. Hexadecanoic acid (palmitic acid) and VOCs such as the sesquiterpenes α-cedrene, β-cedrene, thujopsene, α-santalene, α-selinene, cedrene, (+)-cuparene and δ-cadinene secreted by L. gongylophorus may be responsible for speeding the germination of Escovopsis’ conidia as well as for the faster hyphal development. Based on this study and available literature we infer that the relationship between these two species is mediated by hyphal interference (HI). Additional studies should unveil if the biological activity of some compounds produced by these fungi is attractive, repellent or toxic to the ants and inhibitory to other fungi. São Paulo State University (UNESP) Centre for the Study of Social Insects Campus de Rio Claro São Paulo State University (UNESP) Centre for the Study of Social Insects Campus de Rio Claro

Aim To screen and identify a potential biosurfactant-producing yeast strain isolated from Antarctic soil and to evaluate the fermentation process kinetics of the most promising strain on biosurfactant production using glycerol as carbon source. Methods and results From the 68 isolated yeast strains, 11 strains were able to produce biosurfactants after Emulsification Index (E.I.) and Drop Collapse tests, reaching an E.I. higher than 10%. Strain 1_4.0 was the best producer, identified as Candida glaebosa based on molecular analysis. Yeast was cultivated in a medium composed of glycerol supplemented with yeast extract for 120 h to determine the process kinetics. The increased C/N ratio affected yeast growth and biosurfactant production. Biosurfactant release was associated with the end of exponential and beginning of the stationary growth phases. Results indicated an E.I. of 30% at the end of the fermentation. Conclusions The feasiability of C. glaebosa to produce biosurfactant from a low-cost medium cultivation shows a great impact on the development of bioresource in the Antarctica terrestrial environment. Significance and impact of the study Although the diversity of psychrophilic/psychrotolerant micro-organisms from Antarctica has been the preferred subject of study by microbiologists, terrestrial microfungal communities are scarcely investigated and literature about the biotechnological potential of such micro-organisms should cover important biomolecules in addition to cold-adapted enzymes. In the present study, for the first time, the Maritime Antarctica environment was screened as a novel source of biosurfactants produced by micro-organisms.

Antarctica is the coldest, windiest, and driest continent on Earth. In this sense, microorganisms that inhabit Antarctica environments have to be adapted to harsh conditions. Fungal strains affiliated with Ascomycota and Basidiomycota phyla have been recovered from terrestrial and marine Antarctic samples. They have been used for the bioprospecting of molecules, such as enzymes. Many reports have shown that these microorganisms produce cold-adapted enzymes at low or mild temperatures, including hydrolases (e.g. α-amylase, cellulase, chitinase, glucosidase, invertase, lipase, pectinase, phytase, protease, subtilase, tannase, and xylanase) and oxidoreductases (laccase and superoxide dismutase). Most of these enzymes are extracellular and their production in the laboratory has been carried out mainly under submerged culture conditions. Several studies showed that the cold-adapted enzymes exhibit a wide range in optimal pH (1.0–9.0) and temperature (10.0–70.0 °C). A myriad of methods have been applied for cold-adapted enzyme purification, resulting in purification factors and yields ranging from 1.70 to 1568.00-fold and 0.60 to 86.20%, respectively. Additionally, some fungal cold-adapted enzymes have been cloned and expressed in host organisms. Considering the enzyme-producing ability of microorganisms and the properties of cold-adapted enzymes, fungi recovered from Antarctic environments could be a prolific genetic resource for biotechnological processes (industrial and environmental) carried out at low or mild temperatures. Fil: Duarte, Alysson Wagner Fernandes. Universidade Federal de Alagoas; Brasil. Universidade Estadual de Campinas; Brasil Fil: dos Santos, Juliana Aparecida. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Vianna, Marina Vitti. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Vieira, Juliana Maíra Freitas. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Mallagutti, Vitor Hugo. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Inforsato, Fabio José. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Wentzel, Lia Costa Pinto. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Lario, Luciana Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Centro de Estudios Fotosintéticos y Bioquímicos. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Centro de Estudios Fotosintéticos y Bioquímicos; Argentina. Universidade de Sao Paulo; Brasil Fil: Rodrigues, Andre. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Pagnocca, Fernando Carlos. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Pessoa, Adalberto. Universidade de Sao Paulo; Brasil Fil: Durães Sette, Lara. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil

Made available in DSpace on 2018-12-11T17:17:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01. Added 1 bitstream(s) on 2019-10-09T18:31:28Z : No. of bitstreams: 1 S1517-83822018000100162.pdf: 1170311 bytes, checksum: 5c62aa909a7da5b9932904afc5884cc0 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) For the implementation of cellulosic ethanol technology, the maximum use of lignocellulosic materials is important to increase efficiency and to reduce costs. In this context, appropriate use of the pentose released by hemicellulose hydrolysis could improve de economic viability of this process. Since the Saccharomyces cerevisiae is unable to ferment the pentose, the search for pentose-fermenting microorganisms could be an alternative. In this work, the isolation of yeast strains from decaying vegetal materials, flowers, fruits and insects and their application for assimilation and alcoholic fermentation of xylose were carried out. From a total of 30 isolated strains, 12 were able to assimilate 30 g L−1 of xylose in 120 h. The strain Candida tropicalis S4 produced 6 g L−1 of ethanol from 56 g L−1 of xylose, while the strain C. tropicalis E2 produced 22 g L−1 of xylitol. The strains Candida oleophila G10.1 and Metschnikowia koreensis G18 consumed significant amount of xylose in aerobic cultivation releasing non-identified metabolites. The different materials in environment were source for pentose-assimilating yeast with variable metabolic profile. Universidade Estadual Paulista(UNESP) Instituto de Pesquisa em Bioenergia-IPBen Laboratório de Microbiologia aplicada Universidade Estadual Paulista(UNESP) Instituto de Química Universidade Estadual Paulista-UNESP Centro de Estudos de Insetos Sociais-Ceis Universidade Estadual Paulista(UNESP) Instituto de Pesquisa em Bioenergia-IPBen Laboratório de Microbiologia aplicada Universidade Estadual Paulista(UNESP) Instituto de Química Universidade Estadual Paulista-UNESP Centro de Estudos de Insetos Sociais-Ceis

Aquatic ecotone habitats, like wetlands and phytotelmata, contain higher nutrient levels than are found in open waters resulting from degradation of organic materials like leaf litter. This allows much larger autochthonous yeast populations to develop than in more traditionally studied open water habitats. The single-celled morphology of yeasts makes them naturally better adapted than filamentous fungi to fluid habitats. Heavy influence exists from the extensive phylloplane yeast populations, which have also received little study until recently, and of animals attracted to these resources. Debaryomyces hansenii, Pichia membranifaciens, Candida spp., Papiliotrema laurentii, Naganishia albida, and Rhodotorula mucilaginosa were the most common yeasts detected in these habitats. Some species have a strong association with specific types of aquatic ecotone habitat like Kluyveromyces aestuarii in mangroves, Scheffersomyces spartinae in salt marshes, and Kazachstania bromeliacearum in bromeliad phytotelmata. Yeast diversity in aquatic ecotones is very rich in species occurring at low frequency making these habitats good targets for bioprospecting. The studies of estuaries, mangroves, salt marshes, bogs, and phytotelmata resulted in a list of over 270 identified yeasts and many additional unidentified cultures such as those reported as Candida spp. and as the former polyphyletic genera Cryptococcus spp. and Rhodotorula spp., many of which have since been described as new taxa.

Two novel species, Wickerhamiella kiyanii f.a., sp. nov. (type strain FB1-1DASPT = CBS 12905T = CBMAI 1613T) and Wickerhamiella fructicola f.a., sp. nov. (type strain H10YT = CBS 12902T = CBMAI 1614T) are proposed in the Wickerhamiella clade (Saccharomycetes, Saccharomycetales) to accommodate three strains isolated from flowers and fruits typical of the Brazilian Atlantic rainforest. The novel status of these yeast species was established by sequence divergence observed in the D1/D2 domains of the LSU rRNA gene from the most closely related, described species as well as by phylogenetic analysis. Wickerhamiella kiyanii sp. nov. differs from its nearest phylogenetic neighbours W. pagnoccae CBS 12178T, Candida jalapaonensis CBS 10935T and Candida drosophilae CBS 8459T by 2.2–4.2 % in the D1/D2 sequences. By contrast, a sequence divergence of 13.2–13.8 % was observed between W. fructicola sp. nov. and its closest, described phylogenetic relative Candida kazoui JCM 12558T and Candida hasegawae JCM 12559T. Taxonomic descriptions of the two novel species are given.

A novel yeast species was recovered from the fungus garden of the leaf-cutting ant Acromyrmex balzani (Hymenoptera: Formicidae). The growth of the novel yeast species is limited by its ability to metabolize only a few carbon and nitrogenous compounds. A remarkable characteristic of this strain is the vigorous growth in 1 % acetic acid. Sequence analysis of the D1/D2 domains of the LSU rRNA gene showed that the novel species belongs to the Starmerella clade and is phenotypically and genetically divergent from currently recognized species in this clade. Described here as Starmerella aceti f.a., sp. nov., it differs by 37 nucleotide substitutions in the D1/D2 region from Starmerella jinningensis CBS 11864T, the most closely related species. The type strain of Starmerella aceti sp. nov. is TO 125T ( = CBMAI 1594T = CBS 13086T).

Summary Attine ants maintain an association with antibiotic-producing Actinobacteria found on their integuments. Evidence supports these bacteria as auxiliary symbionts that help ants to defend the fungus gardens against pathogens. Using Pseudonocardia strains isolated from Trachymyrmex ants, we tested whether the inhibitory capabilities of such strains are restricted to Escovopsis parasites that infect gardens of this ant genus. Twelve Pseudonocardia strains were tested in in vitro bioassays against Escovopsis strains derived from fungus gardens of Trachymyrmex (n = 1) and leaf-cutting ants (n = 3). Overall, significant differences were observed in the mycelial growth among each Escovopsis strain in the presence of Pseudonocardia. Particularly, Escovopsis from Acromyrmex and Trachymyrmex were the most inhibited strains in comparison to Escovopsis isolated from Atta. This result suggests that Pseudonocardia isolated from Trachymyrmex possibly secrete antimicrobial compounds effective against diverse Escovopsis strains. The fact that Trachymyrmex ants harbour Pseudonocardia strains with broad spectrum of activity and its defensive role on attine gardens are discussed.

Fungi are a diverse group of organisms with an overall global number of 1.5M up to 3.3M species on Earth. Besides their ecological roles as decomposers, fungi are important in several aspects of applied research. Here, we review how culture collections may promote the knowledge on diversity, conservation and biotechnological exploitation of fungi. The impact of fungi diversity on biotechnological studies is discussed. We point out the major roles of microbial repositories, including fungal preservation, prospecting, identification, authentication and supply. A survey on the World Data Center for Microorganisms (WDCM) powered by the World Federation for Culture Collections and on the Genetic Heritage Management Council (CGEN) database revealed that 46 Brazilian culture collections registered in these databases are dedicate to preserving fungi. Most of these culture collections are located in the Southeast of Brazil. This scenario also demonstrates that Brazil has many collections focused on fungal strains, but the lack of up-to-date information in WDCM as well as of a solid national platform for culture collections registration do not allow accurate assessment of fungal preservation.

The aim of the present study was to investigate the taxonomic identity of yeasts isolated from the Antarctic continent and to evaluate their ability to produce enzymes (lipase, protease and xylanase) at low and moderate temperatures. A total of 97 yeast strains were recovered from marine and terrestrial samples collected in the Antarctica. The highest amount of yeast strains was obtained from marine sediments, followed by lichens, ornithogenic soils, sea stars, Salpa sp., algae, sea urchin, sea squirt, stone with lichens, Nacella concinna, sea sponge, sea isopod and sea snail. Data from polyphasic taxonomy revealed the presence of 21 yeast species, distributed in the phylum Ascomycota (n = 8) and Basidiomycota (n = 13). Representatives of encapsulated yeasts, belonging to genera Rhodotorula and Cryptococcus were recovered from 7 different Antarctic samples. Moreover, Candida glaebosa, Cryptococcus victoriae, Meyerozyma (Pichia) guilliermondii, Rhodotorula mucilaginosa and R. laryngis were the most abundant yeast species recovered. This is the first report of the occurrence of some species of yeasts recovered from Antarctic marine invertebrates. Additionally, results from enzymes production at low/moderate temperatures revealed that the Antarctic environment contains metabolically diverse cultivable yeasts, which could be considered as a target for biotechnological applications. Among the evaluated yeasts in the present study 46.39, 37.11 and 14.43 % were able to produce lipase (at 15 °C), xylanase (at 15 °C) and protease (at 25 °C), respectively. The majority of lipolytic, proteolytic and xylanolytic strains were distributed in the phylum Basidiomycota and were mainly recovered from sea stars, lichens, sea urchin and marine sediments.

International audience; The marine environment offers both economic and scientific potential which are relatively untapped from a biotechnological point of view. These environments whilst harsh are ironically fragile and dependent on a harmonious life form balance. Exploitation of natural resources by exhaustive wild harvesting has obvious negative environmental consequences. From a European industry perspective marine organisms are a largely underutilised resource. This is not due to lack of interest but due to a lack of choice the industry faces for cost competitive, sustainable and environmentally conscientious product alternatives. Knowledge of the biotechnological potential of marine organisms together with the development of sustainable systems for their cultivation, processing and utilisation are essential. In 2010, the European Commission recognised this need and funded a collaborative RTD/SME project under the Framework 7-Knowledge Based Bio-Economy (KBBE) Theme 2 Programme ‘Sustainable culture of marine microorganisms, algae and/or invertebrates for high value added products’. The scope of that project entitled ‘Sustainable Production of Biologically Active Molecules of Marine Based Origin’ (BAMMBO) is outlined. Although the Union is a global leader in many technologies, it faces increasing competition from traditional rivals and emerging economies alike and must therefore improve its innovation performance. For this reason innovation is placed at the heart of a European Horizon 2020 Strategy wherein the challenge is to connect economic performance to eco performance. This article provides a synopsis of the research activities of the BAMMBO project as they fit within the wider scope of sustainable environmentally conscientious marine resource exploitation for high-value biomolecules.

Xylose is the main sugar in hemicellulosic hydrolysates and its fermentation into ethanol by microorganisms is influenced by nutritional factors, such as nitrogen source, vitamins and other elements. Rice bran extract (RBE) is an inexpensive nitrogen source primarily consisting of high amount of protein. This study evaluates the potential of RBE as a nitrogen source for the “hemicellulosic ethanol” production from sugarcane bagasse dilute acid hydrolysate by novel yeast strains Scheffersomyces shehatae (syn. Candida shehatae) CG8-8BY and Spathaspora arborariae UFMG-HM19.1A, isolated from Brazilian forests. Two different media formulations were used for inoculum preparation and production medium, using yeast extract and RBE as nitrogen sources. S. shehatae CG8-8BY showed ethanol production of 17.0 g/l with the ethanol yield (0.33 g/g) and fermentation efficiency (64 %) from medium supplemented with RBE. On the other hand, S. arborariae presented 5.4 g/l of ethanol production with ethanol yield (0.14 g/g) and fermentation efficiency (21 %) in a fermentation medium supplemented with RBE. Appropriate media formulation is an important parameter to increase the productivity of bioconversion process and RBE proved to be an efficient and inexpensive nitrogen source to supplement sugarcane bagasse hemicellulosic hydrolysate for second generation ethanol production.

Made available in DSpace on 2020-12-10T18:03:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Bioconversion of hemicellulosic hydrolysates into ethanol with the desired yields plays a pivotal role for the overall success of biorefineries. This paper aims to evaluate the ethanol production potential of four native strains of Scheffersomyces shehatae (syn. Candida shehatae) viz. S. shehatae BR6-2AI, CG8-8BY, PT1-1BASP and BR6-2AY, isolated from Brazilian forests. These strains were grown in commercial D-xylose-supplemented synthetic medium and sugarcane bagasse hemicellulose hydrolysate. S. shehatae BR6-2AY showed maximum ethanol production [0.48 +/- 0.019 g g(-1), 95 +/- 3.78 % fermentation efficiency (FE)] followed by S. shehatae CG8-8BY (0.47 +/- 0.016 g g(-1), 93 +/- 3.12 % FE), S. shehatae BR6-2AI (0.45 +/- 0.01 g g(-1), 89 +/- 1.71 % FE) and S. shehatae PT1-1BASP (0.44 +/- 0.02 g g(-1), 86 +/- 3.37 % FE) when grown in synthetic medium. During the fermentation of hemicellulose hydrolysates, S. shehatae CG8-8BY and S. shehatae BR6-2AY showed ethanol production (0.30 +/- 0.05 g g(-1), 58 +/- 0.02 % FE) and (0.21 +/- 0.01 g g(-1), 40 +/- 1.93 % FE), respectively. Univ Sao Paulo, Engn Sch Lorena, Dept Biotechnol, BR-12602810 Lorena, SP, Brazil Univ Estadual Paulista, Ctr Estudos Insetos Sociais, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Ctr Estudos Insetos Sociais, BR-13506900 Rio Claro, SP, Brazil

Leaf-cutting ants modify the properties of the soil adjacent to their nests. Here, we examined whether such an ant-altered environment impacts the belowground fungal communities. Fungal diversity and community structure of soil from the fungus garden chambers of Atta sexdens rubropilosa and Atta bisphaerica, two widespread leaf-cutting ants in Brazil, were determined and compared with non-nest soils. Culture-dependent methods revealed similar species richness but different community compositions between both types of soils. Penicillium janthinellum and Trichoderma spirale were the prevalent isolates in fungus chamber soils and non-nest soils, respectively. In contrast to cultivation methods, analyses of clone libraries based on the internal transcribed spacer (ITS) region indicated that richness of operational taxonomic units significantly differed between soils of the fungus chamber and non-nest soils. FastUnifrac analyses based on ITS sequences further revealed a clear distinction in the community structure between both types of soils. Plectania milleri and an uncultured Clavariaceae fungus were prevalent in fungus chamber soils and non-nest soils, respectively. FastUnifrac analyses also revealed that fungal community structures of soil from the garden chambers markedly differed among ant species. Our findings suggest that leaf-cutting ants affect fungal communities in the soil from the fungus chamber in comparison to non-nest soils.

Mutualistic associations shape the evolution in different organism groups. The association between the leaf-cutter ant Atta sexdens and the basidiomycete fungus Leucoagaricus gongylophorus has enabled them to degrade starch from plant material generating glucose, which is a major food source for both mutualists. Starch degradation is promoted by enzymes contained in the fecal fluid that ants deposit on the fungus culture in cut leaves inside the nests. To understand the dynamics of starch degradation in ant nests, we purified and characterized starch degrading enzymes from the ant fecal fluid and from laboratory cultures of L. gongylophorus and found that the ants intestine positively selects fungal α-amylase and a maltase likely produced by the ants, as a negative selection is imposed to fungal maltase and ant α-amylases. Selected enzymes are more resistant to catabolic repression by glucose and proposed to structure a metabolic pathway in which the fungal α-amylase initiates starch catalysis to generate byproducts which are sequentially degraded by the maltase to produce glucose. The pathway is responsible for effective degradation of starch and proposed to represent a major evolutionary innovation enabling efficient starch assimilation from plant material by leaf-cutters.

Crude hydroalcoholic extracts (HA) and twelve compounds isolated from Siphoneugena densiflora O. Berg and Vitex polygama Cham. were tested in vitro as growth inhibitors of the fungus Leucoagaricus gongylophorus (Singer) Moller, that lives in symbiosis with the leaf-cutting ant Atta sexdens, as well as inhibitors of the fungus’ pectinases. Also, the effects of the extracts and the compounds were assessed in a panel of bacteria and yeasts similar to those living in symbiosis with the ant. HA extracts from S. densiflora displayed significant antimicrobial results, mainly against Pseudomonas aeruginosa. Caffeoyl 6-O-β-D-glucopyranoside was the most promising compound in the control of L. gongylophorus growth.

A novel basidiomycetous yeast was isolated from the waste deposit of the attine ant Acromyrmex lundii (Hymenoptera: Formicidae). The field colony was located in Santurce town, Santa Fe province, Argentina. The description of the novel species was based on strain LLU043T. Analysis of the D1/D2 domains of the LSU rRNA gene sequences in GenBank demonstrated that strain LLU043T, belongs to the Rhodosporidiobolus clade and is closely related to Rhodosporidiobolus lusitaniae and Rhodosporidiobolus colostri with 97 % similarity to the two species. The novel species differs from R . lusitaniae and R. colostri in some physiological characteristics such as the lack of assimilation of cellobiose, salicin, succinate, citrate and ethylamine. The name Rhodosporidiobolus geoffroeae sp. nov. is proposed, with LLU043T (=CBS 12828T=CBMAI 1618T) as the type strain.

In order to investigate the intraspecific variability in Hannaella kunmingensis, 11 isolates, including the type strain, were analyzed for their morphological and biochem- ical traits. The combined internal transcribed spacer region (ITS), D1/D2 domains of the large subunit rDNA (LSU), and cytochrome b gene were examined using phylogenetic and parsimony network analyses. Our investigations revealed differences in colony morphology as well as differences in 31 out of 64 phenotypic characteristics exam- ined, including growth in lactose, vitamin free medium, xylitol, L-arabinitol, and nitrite. Growth in the presence of 0.1 % cycloheximide was also highlighted in H. kunmin- gensis. All the 11 strains were conspecific in the LSU; however, variations of about 2.5 % were found in the ITS while isolate CBS 8356 exhibited a 27.3 % divergence from the other strains in the cytochrome b gene. Parsimony net- work analysis revealed the existence of three haplotypes among the H. kunmingensis strains studied but excluded CBS 8356 from the network connecting these haplotypes. This study contributes to the knowledge of the intraspecific diversity of H. kunmingensis. To accommodate such intra- specific variations, an emendation of the species diagnosis is proposed.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:23Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:37Z : No. of bitstreams: 1 2-s2.0-84856960037.pdf: 1740238 bytes, checksum: 27cdd7c0aeb63441f4d336c06455fee5 (MD5) Made available in DSpace on 2014-05-27T11:26:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-15 The phytochemical study of Virola sebifera leaves led to the isolation of three lignans: (+)-sesamin, (-)-hinokinin, and (-)-kusunokinin and three flavonoids: quercetin-3-O - L-rhamnoside, quercetin-3-O - D-glucoside, and quercetin-3-methoxy-7-O - D-glucoside by using techniques as high-speed counter-current chromatography and high-performance liquid chromatography. The crude extracts, fractions, and isolated compounds were evaluated for their insecticidal and fungicidal potential against Atta sexdens rubropilosa and its symbiotic fungus Leucoagaricus gongylophorus. The bioassay results showed a high insecticidal activity for the methanol crude extract of the leaves of V. sebifera and its n-hexane, dichloromethane and ethyl acetate fractions. The fungicidal bioassay revealed high toxicity of the lignans against L. gongylophorus. © 2012 Keylla Utherdyany Bicalho et al. Departamento de Química Universidade Federal de São Carlos, CP 13565-905 São Carlos, SP Centro de Estudos de Insetos Sociais Universidade Estadual Paulista Campus Rio Claro, CP 199, 13506-900 Rio Claro, SP Centro de Estudos de Insetos Sociais Universidade Estadual Paulista Campus Rio Claro, CP 199, 13506-900 Rio Claro, SP

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:27Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:40Z : No. of bitstreams: 1 2-s2.0-84859727457.pdf: 4104183 bytes, checksum: b4b94f297edf2ed59e7c8c7624db77de (MD5) Made available in DSpace on 2014-05-27T11:26:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-18 Ants in the tribe Attini (Hymenoptera: Formicidae) comprise about 230 described species that share the same characteristic: all coevolved in an ancient mutualism with basidiomycetous fungi cultivated for food. In this paper we focused on fungi other than the mutualistic cultivar and their roles in the attine ant symbiosis. Specialized fungal parasites in the genus Escovopsis negatively impact the fungus gardens. Many fungal parasites may have small impacts on the ants' fungal colony when the colony is balanced, but then may opportunistically shift to having large impacts if the ants' colony becomes unbalanced. Copyright © 2012 Fernando C. Pagnocca et al. Centre for the Study of Social Insects São Paulo State University (UNESP), 13506-900 Rio Claro, SP Department of Biochemistry and Microbiology São Paulo State University (UNESP), 13506-900 Rio Claro, SP Centre for the Study of Social Insects São Paulo State University (UNESP), 13506-900 Rio Claro, SP Department of Biochemistry and Microbiology São Paulo State University (UNESP), 13506-900 Rio Claro, SP

Leaf-cutting ants (Formicidae: Attini) are considered pests in agriculture for their impact in human crops, as they utilize leaf fragments to raise their fungal mutualist (Agaricales: Lepiotaceae). Basically, the basidiomycetous fungus is cultivated to supply food to adult workers and broads; in return, the ants protect it against natural enemies. However, recent studies have claimed that other microorganisms are associated to ant nests where a wide range of interactions may take place. To investigate the occurrence of dematiaceous fungi on the cuticle of Atta laevigata ants, 30 workers were sampled from an adult nest located in the surroundings of the Center for the Studies of Social Insects, UNESP-Rio Claro, SP, Brazil. The use of selective techniques to avoid high-sporulation fungi has been recommended and was tested in this study. To favor the isolation of the desired fungi, heads and cuticle scrapings of ant bodies were inoculated on Mycosel agar and incubated for 3 weeks at 35°C. Morphological and molecular methods were used to identify the filamentous fungi recovered. From 56 isolates, 19 were hyaline filamentous species, and among the remaining 37, some are mentioned as phyto-associated fungi like Alternaria arborescens, Bipolaris sorokiniana, Bipolaris eleusines, Bipolaris zeae, Curvularia trifolii, and Paraphaeosphaeria michotii. These species are reported from A. laevigata bodies for the first time. None of the isolation trials revealed the presence of the parasite Escovopsis or entomopathogenic fungi. The possible spread of the fungi in nature by the ants is discussed.

Considerable losses during apple fruit storage occur due to microbiological diseases, mainly caused by Penicillium expansum, which in addition to fruit pulp deterioration produces patulin, a mycotoxin with carcinogenic and teratogenic activity. Biological control of post-harvest disease by antagonist yeasts focused on killer toxins is an appreciable alternative to the chemical fungicides, due to the low possibility of toxic residues demonstrated during fermentative processes. Twenty out of 44 yeasts (16 isolated from fruits, 10 from corn silage and 18 from laboratory anthill), showed antagonism against spores of P. expansum. The assay in solid medium pointed the strongest nutrient competition antagonism by D. hansenii strain C1 (31 mm inhibition diameter), while D. hansenii strain C7 (15 mm) showed higher antibiosis and parasitism pattern. In the following step the extracellular activity was tested performing the assay with culture supernatant in Yeast Medium agar, where C. guilliermondii P3 was more effective against conidia germination (inhibition rate of 58.15%) while P. ohmeri showed better inhibition on micelial growth (66.17%). The antibiosis showed by both yeasts could suggest probable mechanism associated with killer phenomenon, once both strains were killer positive against sensitive reference strains (S. cerevisiae NCYC 1006 and P. kluyveri CAY-15). In order to enhance the production of antifungal substance, these yeasts were cultivated with P. expansum, but the difference between culture supernatant obtained from yeasts cultivated alone and with mould was not significant (P > 0.05). The results demonstrated that the yeasts application constitute a promising tool, enhancing the biological control of P. expansum in post-harvest diseases of apple fruit.As perdas consideráveis no armazenamento de maçãs decorrem principalmente de desordens microbiológicas, causadas por Penicillium expansum, que além de colonizar o fruto e causar dano à polpa, produz a patulina, micotoxina teratogênica e cancerígena. Entre as alternativas ao tradicional tratamento químico de doenças pós-colheita de frutos, enfoca-se o biocontrole por leveduras antagonistas, com ênfase em linhagens killer, em função da baixa possibilidade de resíduos tóxicos e com ampla inocuidade demonstrada nos processos fermentativos. O objetivo deste trabalho foi analisar o potencial antagônico de leveduras no controle de P. expansum, mediante antifungigrama em meio sólido e líquido. Do total de 44 leveduras isoladas (16 de frutas, 10 de silagem de milho e 18 de formigueiro de laboratório), 20 apresentaram antagonismo perante esporos de P. expansum em ágar Meio Para Levedura, sendo Debaryomyces hansenii C1 responsável por maior atividade associada à competição por nutrientes (zona de inibição de 31 mm) e D. hansenii C7 por antibiose/hiperparasitismo (15 mm). Entretanto, o ensaio realizado com o sobrenadante de cultivo reduziu o número de cepas ativas em cinco, sendo Pichia ohmeri 158 e Candida guilliermondii P3 as de maior atividade antagônica. No antifungigrama em meio líquido (caldo MPL) o sobrenadante do cultivo de C. guilliermondii (25ºC/72 horas) inibiu 58,15% da germinação dos esporos de P. expansum e P. ohmeri (25ºC/48 horas) inibiu o desenvolvimento de hifas em 66,17%. A atividade do meio extracelular baseado em antibiose sugeriu mecanismo associado ao caráter killer, uma vez que ambas as leveduras foram positivas perante as linhagens padrão S. cerevisiae NCYC 1006 e P. kluyveri CAY-15. A diferença entre os sobrenadantes obtidos do cultivo destas leveduras isoladamente e em interação com o fungo teste, visando estímulo adicional na produção de substância antifúngica, não foi significativa (P > 0,05). De acordo com os resultados obtidos, conclui-se que a aplicação de leveduras antagonistas constitui ferramenta promissora no controle biológico de P. expansum em pós-colheita de maçã.

We profiled the microfungal communities in gardens of fungus-growing ants to evaluate possible species-specific ant-microfungal associations and to assess the potential dependencies of microfungal diversity on ant foraging behavior. In a 1-year survey, we isolated microfungi from nests of Cyphomyrmex wheeleri, Trachymyrmex septentrionalis and Atta texana in Central Texas. Microfungal prevalence was higher in gardens of C. wheeleri (57%) than in the gardens of T. septentrionalis (46%) and A. texana (35%). Culture-dependent methods coupled with a polyphasic approach of species identification revealed diverse and changing microfungal communities in all the sampling periods. Diversity analyses showed no obvious correlations between the number of observed microfungal species, ant species, or the ants' changing foraging behavior across the seasons. However, both correspondence analysis and 5.8S-rRNA gene unifrac analyses suggested structuring of microfungal communities by ant host. These host-specific differences may reflect in part the three different environments where ants were collected. Most interestingly, the specialized fungal parasite Escovopsis was not isolated from any attine garden in this study near the northernmost limit of the range of attine ants, contrasting with previous studies that indicated a significant incidence of this parasite in ant gardens from Central and South America. The observed differences of microfungal communities in attine gardens suggest that the ants are continuously in contact with a diverse microfungal species assemblage.

The present work profiled the fungal community structure found in Brazilian energy transmission tower with signs of corrosion and/or biofilm formation using cloning (ITS-rRNA gene libraries) and culture-dependent technique. A total of 31 isolates comprising 10 filamentous fungi and 21 yeasts were recovered from enrichment cultures. As determined by polyphasic taxonomy 9 genera and 13 species were identified including Aspergillus fumigatus, Aspergillus niger, Candida albicans, Candida pseudointermedia, Candida tropicalis, Cryptococcus laurentii, Debaryomyces nepalensis, Exophiala dermatitidis, Fusarium sp., Fusarium solani, Paecilomyces lilacinus, Trichoderma citrinoviride, Trichoderma longibrachiatum, and Pichia guilliermondii. Metagenomic analyses based on 160 clone sequences revealed 30 operational taxonomic units (OTUs) comprising 20 OTUs of filamentous fungi and 10 OTUs of yeasts. The majority of OTUs were related to the genera Capnobotryella, Cryptococcus, Devriesia, Fellomyces, Fusarium, Kockovaella, Panaeolus, Rhodotorula, Sirobasidium, Sporobolomyces, Strelitziana and Teratosphaeria. Although members of the fungal community from transmission tower samples are ubiquitous fungi commonly found in other environments, some have been related to microbiologically-influenced corrosion of metals. Comparisons between fungal community composition obtained by both culture-dependent and independent methods highlighted the different aspects of the mycobiota, emphazising the need of complementary approaches to assess the microbial assemblage of unusual environments.