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No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Georgea Santos Nogueira de Melo.pdf: 3075368 bytes, checksum: 62acdc362c28ad7addc7e6bd3effcc51 (MD5) Previous issue date: 2016-02-26 / CAPES / O presente trabalho investigou a dinâmica da comunidade de fungos poroides em remanescentes de Floresta Atlântica de Pernambuco, baseado na hipótese de que fatores bióticos e abióticos influenciam significativamente seus padrões estruturais. O estudo ecológico foi conduzido em três fragmentos em diferentes estágios de regeneração da RPPN Frei Caneca: Barragem das Moças, Caranha e Serra do Quengo. Em cada fragmento foram estabelecidas unidades amostrais, compostas por três transectos, visitadas durante 12 meses entre 2012 e 2013. Os fungos encontrados ao longo dos transectos foram levados para laboratório, analisados macro e microscopicamente e identificados. Espécies interessantes ou novas para a ciência foram analisadas também com métodos de biologia molecular. As variações na composição, riqueza e abundância das espécies foram investigadas ao longo dos fragmentos e do tempo em relação aos fatores climáticos: “precipitação”, “temperatura” e “umidade relativa do ar” e aos fatores do substrato: “pH”, “dureza”, “umidade relativa do tronco”, “temperatura da madeira”, “volume” e “área superficial”. As diferenças encontradas foram testadas através do teste de qui-quadrado e a ANOSIM, utilizando o índice de Bray-Curtis. A influência do substrato foi testada através da análise de correspondência retificada, utilizando o coeficiente de correlação de Spearman. Além disso, foi calculado o índice de Shannon-Wiener para medir a diversidade dos fragmentos e o coeficiente de correlação de Pearson para medir o grau da correlação entre seus valores. Duas ordens, nove famílias, 45 gêneros e 74 espécies foram encontradas. Destas, 17 foram coletadas pela primeira vez na Floresta Atlântica de Pernambuco, representando novos registros para a América do Sul, Brasil e Nordeste. Os fragmentos diferiram em relação ao tempo de regeneração (idade), tamanho, histórico de perturbações e grau de isolamento, porém não significativamente em relação à composição de espécies da comunidade fúngica. A mata com maior histórico de perturbação foi também a que apresentou maior número de espécies fúngicas. A distribuição dos fungos foi influenciada principalmente pelos fatores “fragmento” e “umidade relativa do ar”. A diversidade de fungos foi diferente entre fragmentos, mas não entre meses. Todavia, a abundância foi maior durante a estação chuvosa. A maioria das espécies ocorreu em troncos de 10 a 30m² e com até 1m³. Contudo, os resultados de qui-quadrado não foram significativos nem em relação à área, nem em relação ao volume. O pH foi a única variável com correlação significativa entre fatores do substrato analisados, . A maioria das espécies ocorreu em pH de 3 a 5, mas a acidez encontrada no substrato pode ter sido decorrente da presença dos basidiomas e, consequentemente, do processo natural de decomposição da madeira. O presente estudo concluiu que: a diversidade de fungos pode refletir as características do fragmento, uma vez que o fator “área de coleta” é mais determinante que o fator “tempo” na ocorrência e composição das espécies e que, em ambientes úmidos, a quantidade de água no substrato é um fator determinante para a produção de basidiomas, independente de suas variações mensais. / This study investigated the dynamic of poroid fungi community in remnants of Atlantic Forest from Pernambuco, based on the hypothesis that biotic and abiotic factors significantly influence their structural patterns. The ecological study was conduced in three remnants of different regeneration stages in the RPPN Frei Caneca: Barragem das Moças, Caranha and Serra do Quengo. In each remnant sampling units were established, consisting of three transects visited during 12 months between 2012 and 2013. The fungi found in these transects were taken to the laboratory, analyzed macro and microscopically and identified. Interesting and new species to science were also analyzed under molecular biology methods. Variations in composition, richness and abundance of species were investigated in the remnants and according to a gradient of time in relation to climatic factors: “precipitation”, “temperature” and “relative humidity of the air”, and the substrate factors: “pH”, “hardness of the trunk”, “water abosortion capacity”, “wood temperature”, “volume” and “surface area”. Differences found were tested by the qui-square test and ANOSIM, using the Bray-Curtis index. The influence of substrate was tested by Detrended Correspondence Analysis, using the Spearman’s rank correlation coefficient. In addition, the index of Shannon-Wiener was calculated to measure the diversity of remnants and the Pearson’s coefficient of variation the degree of correlation between these values. Two orders, nine families, 45 genera and 74 species were identified, of which 17 were collected for the first time in the Atlantic Forest of Pernambuco and represents new records from South America, Brazil and Northeast region. The remnants differed in terms of age, size, anthropogenic disturbance and degree of isolation, but not significantly in terms of fungal community. The remnant more disturbed was also the one that presented the highest number of fungal species. The distribution of fungi was mainly influenced by: "fragment" and "relative humidity of air". The diversity of fungi was different between remnants, but not between months. However, the abundance was higher during the rainy season. Most of the species occurred in logs of area 10 to 30m² and volume 1m³. The chi-square results were not significant either in relation to the area, nor to the volume.Of the analyzed factors of substrate, the only variable with significant correlation was pH. Most species occurred at pH of 3 to 5, but the acidity found in the substrate may be due to the presence of the fungi and hence the natural process of decomposition of wood. This study concluded that: a diversity of fungi can reflect the characteristics of the fragment, since the factor “study site” is even more crucial that the factor “time” in occurrence and species composition, and that in moist environments, the amount of water in the substrate, regardless of their monthly variations, is a determining factor for the basidiomata production.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

A biopolpação consiste no biotratamento de madeira por fungos degradadores de lignina como etapa prévia à produção de polpa celulósica. De uma forma geral, as madeiras biotratadas facilitam os processos posteriores de polpação. Entretanto, ensaios anteriores que avaliaram a biopolpação em escala piloto mostraram que é difícil estabelecer os cultivos de basidiomicetos de interesse livre de bolores contaminantes, já que não é fácil controlar perfeitamente a assepsia durante a inoculação. Para contribuir com o avanço do processo de biopolpação, este trabalho avaliou os cultivos mistos de Ceriporiopsis subvermispora e Phanerochaete chrysosporium sobre madeira de Eucalyptus grandis e Eucalyptus urograndis em regimes de incubação em temperaturas variáveis e em condições não assépticas. A estratégia de iniciar os cultivos em temperatura mais elevada (37°C) e depois manter as culturas em temperaturas variáveis de 27°C e 37°C se mostrou eficiente para inibir o crescimento de contaminantes indesejáveis tanto nos cultivos mistos como nos individuais de cada espécie avaliada. Para avaliar o efeito do biotratamento da madeira numa etapa subsequente de polpação quimiotermomecânica (CTMP) foi feito um estudo preliminar de ajuste de variáveis de polpação por refinamento mecânico de cavacos pré-digeridos com licor alcalino contendo sulfito de sódio. Os dados mostraram que é possível simular o rendimento e as características fisico-mecânicas de polpas industriais empregando uma etapa de pré-digestão dos cavacos com 6% de Na2SO3 e 3% de NaOH a 120°C por 2 h, seguida de desfibramento e refino em refinador de discos. As curvas de refino nesse processo CTMP mostraram que os cavacos biotratados deram origem a polpas com 300 mL de Freeness (CSF) consumindo menos energia do que o observado para o refino da madeira controle. As economias de energia chegaram a 60% em alguns casos, porém não foram maximizadas pelo efeito sinérgico do cultivo misto dos dois basidiomicetos em questão. Experimentos adicionais foram desenvolvidos empregando as espécies fúngicas Pycnoporus sanguineus e Trametes versicolor que foram eficientes para competir com contaminantes mesmo a 27oC. Neste caso, as economias de energia no processo CTMP subsequente somente foram obtidas com tempos mais longos de biotratamento (30 dias) e ainda assim os valores obtidos foram inferiores àqueles obtidos com as madeiras biotratadas por C. subvermispora e P. chrysosporium. Também a combinação das espécies C. subvermispora e Pleurotus ostreatus foi avaliada. Neste caso havia informação prévia da literatura indicando um efeito sinérgico da ação das duas espécies no que diz respeito a secreção da enzima manganês-peroxidase (MnP) e na degradação de lignina. Os resultados corroboraram que os cultivos mistos de C. subvermispora e P.ostreatus proporcionam maior produção de MnP do que os cultivos individuais de cada espécie. Por outro lado, P. ostreatus foi ineficiente para promover a redução do consumo de energia no processo CTMP subsequente. Os cultivos mistos também não proporcionaram efeito superior àquele observado com o cultivo individual de C. subvermispora. / Biopulping involves the wood biotreatment by selected white-rot fungi as a pretreatment step of conventional pulping processes. In general, the biotreated wood facilitates the subsequent pulping processes. However, previous studies on pilot scale showed that the process is susceptible to contamination by molds when the inoculation and biodegradation steps are carried out under non-aseptic conditions. To contribute with the biopulping progress this study evaluated the use of mixed cultures of Ceriporiopsis subvermispora and Phanerochaete chrysosporium acting on Eucalyptus grandis and Eucalyptus urograndis wood under non aseptic conditions where incubation was performed at varied temperatures. The simple strategy of initiating the incubation at 37°C for 3 days followed by a non-controlled step where the temperature could oscillate in the range of 27°C to 37°C proved to be efficient to inhibit the growth of contaminants. To evaluate the wood biotreatment effect in a subsequent step of chemithermomechanical pulping (CTMP), a preliminary study to adjust pulping variables was performed. Wood chips were predigested with alkaline-sulfite liquor, fibrillated and refined in a disk refiner. It was possible to simulate the yield and physico-mechanical properties of industrial CTMP pulps using a pre-digestion stage with 6% of Na2SO3 and 3% of NaOH at 120°C for 2 h. The refing curves in the CTMP process showed that the biotreated chips required less energy to reach 300 mL of Freeness (CSF) in the pulps than energy required to refine the control wood chips. Energy savings reached 60% in some cases, but were not maximized by the eventual synergic effect of the mixed cultures of the two basidiomycetes. Additional experiments were developed using the fungal species Trametes versicolor and Pycnoporus sanguineus that were efficient to compete with contaminants even at 27°C. In this case, the energy savings in the subsequent CTMP process were obtained only after long biotreatment times (30 days) and these values were lower than those obtained with the biotreated wood by C. subvermispora and P. chrysosporium. The combination C. subvermispora and Pleurotus ostreatus was also evaluated. In this case, previous literature information indicated some synergic effect of the two species regarding secretion of manganese peroxidase (MnP) and lignin degradation. The results corroborated that the mixed cultures of C. subvermispora and P.ostreatus provided an increased production of MnP compared to the individual cultivation of each species. On the other hand, P.ostreatus was not efficient to promote energy savings in the subsequent CTMP process. The mixed cultures did not provide increased energy savings as compared with the individual biotreatment with C. subvermispora.

Made available in DSpace on 2017-07-10T17:37:47Z (GMT). No. of bitstreams: 1 Tatiane_Martinazzo_Portz.pdf: 1324965 bytes, checksum: 6d1d137717d451f4bdd339fcc445a5bb (MD5) Previous issue date: 2011-06-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The biochemical composition of fungi can vary with climatic conditions and cultivation substrate. Several species have shown biochemical activities, such as Pycnoporus sanguineus, which is highlighted by orange to red color of their basidiocarps. Although the antimicrobial activity verified in various fields such as pharmaceutical, industrial and agricultural, there is no method for growing basidiocarps described in the literature. This work aimed to develop a substrate with Eucalyptus sp. for the cultivation of P. sanguineus and production of basidiocarps. There were two assays, and in vitro and in formulated substrate, developed in the Unioeste, Campus of Marechal Cândido Rondon. We used sawdust of Eucalyptus sp. Separate in two particle sizes: less than 500 microns (G1) and between 500 and 841 microns (G2). In the in vitro assay were used four isolates of P. sanguineus (Ps04, Ps08, PS13 and PS14), grown in Petri dishes containing culture medium CBA plus sawdust in the proportions of zero, 1, 5, 10 and 15% for both sizes. In each dish was peaked a 0.5 cm disc containing mycelium and kept in dark at 25±2ºC, until the first treatment to reach the edge of the Petri dish. Was evaluated the diameter of colony, growth rate of mycelium, the fresh weight of mycelium and production of the pigment cinnabarin. The experiment was DIC in 4x2x5 factorial design, four isolates of P. sanguineus, two particle size of sawdust of Eucalyptus sp. and five concentrations of sawdust added to the culture medium, both with six repetitions. In the assay with formulated substrate, we used two isolates of P. sanguineus (Ps08 and Ps14), grown in polypropylene bags of 28x16 cm, containing sawdust of Eucalyptus sp. and rice bran. At zero, 5 and 20%, particle size in G1 and G2, with humidity of 75% and compacted to 0.5 g mL-1. The substrates remained 30 days in BOD at 25±2ºC, then taken to the greenhouse. Two havest of basidiocarps were made, at 90 and 180 days. Where were evaluated diameter, fresh and dry weight, the average number of basidiocarps and production cinnabarin. Was used experimental DIC in 2x2x3 factorial design, with two isolates of P. sanguineus, two particle size of sawdust of Eucalyptus sp. and three concentrations of rice bran added to sawdust, both with six repetitions. Was observed that the sawdust of Eucalyptus sp. is suitable for substrate for the production of basidiocarps of P. sanguineus, which is G1 showed better results only in vitro assays, while on substrate, the two particle sizes showed good results for the production isolates of P. sanguineus. The Ps08, produced more mass of basidiocarps, while the Ps14 showed higher content of cinnabarin in the basidiocarps. It can be concluded that the genetic characteristics of the biological potential of the isolates of P. sanguineus are more related to productive results that the characteristics of substrates used in this research / A composição bioquímica dos fungos pode variar com condições climáticas de cultivo e substrato. Diversas espécies têm mostrado atividades bioquímicas, como o Pycnoporus sanguineus, que se destaca pela coloração vermelho-alaranjada de seus basidiocarpos. Embora este fungo possua atividade antimicrobiana estudada em diversas áreas, como farmacêutica, industrial e agrícola, não há nenhum método para cultivo de basidiocarpos descrito na literatura. Este trabalho objetivou desenvolver substrato com resíduos madeireiros de Eucalyptus sp. para o cultivo de P. sanguineus e produção de basidiocarpos. Realizaram-se dois ensaios, in vitro e em substrato formulado, desenvolvidos na UNIOESTE, Campus de Marechal Cândido Rondon. Utilizou-se serragem de madeira de Eucalyptus sp., separada em duas granulometrias: inferior a 500 micra (G1) e entre 500 e 841 micra (G2). No ensaio in vitro utilizaram-se quatro isolados de P. sanguineus (Ps04, Ps08, Ps13 e Ps14), cultivados em placas de Petri contendo meio de cultura CBA acrescidos de serragem nas proporções de zero, 1, 5, 10 e 15%, para as duas granulometrias. Em cada placa foi repicado um disco de 0,5 cm contendo micélio e mantidos em ambiente escuro a 25±2ºC, até que o primeiro tratamento atingisse a borda da placa de Petri. Avaliou-se diâmetro de colônia, velocidade de crescimento do micélio, a massa fresca do micélio e a produção do pigmento cinabarina. O delineamento experimental foi DIC, em esquema fatorial 4x2x5, sendo quatro isolados de P. sanguineus, duas granulometrias de serragem de Eucalyptus sp. e cinco concentrações de serragem acrescidos ao meio de cultivo, ambos com seis repetições. No ensaio em substrato formulado, utilizou-se dois isolados de P. sanguineus (Ps08 e Ps14), cultivados em sacos de polipropileno de 28x16 cm, contendo serragem de Eucalyptus sp. e farelo de arroz, nas proporções de zero, 5 e 20%, nas granulometrias G1 e G2, com umidade de 75% e compactados a 0,5 g mL-1. Os substratos permaneceram 30 dias em BOD a 25±2ºC e então foram levados a casa de vegetação. Realizaram-se duas coletas de basidiocarpos, a primeira após 90 dias e a segunda após 180 dias do ensaio em casa de vegetação. A cada coleta avaliou-se o diâmetro, as massas fresca e seca, o número médio de basidiocarpos e a produção do pigmento cinabarina. Utilizou-se delineamento experimental DIC, em esquema fatorial 2x2x3, sendo dois isolados de P. sanguineus, duas granulometrias de serragem de Eucaliptus sp. e três concentrações de farelo de arroz adicionadas a serragem, ambos com seis repetições. Foi observado que a serragem de Eucalyptus sp. é apropriada para formulação de substrato para produção de basidiocarpos de P. sanguineus, sendo a que G1 mostrou melhores resultados apenas nos ensaios in vitro. Nos ensaios em substrato formulado, as duas granulometrias mostraram bons resultados produtivos para os isolados de P. sanguineus. O Ps08, nos ensaios em substrato formulado, teve produção de massa de basidiocarpos, enquanto o Ps14 mostrou maior teor de cinabarina nos basidiocarpos. Pode-se concluir que as características genéticas de potencial biológico dos isolados de P. sanguineus estão mais relacionados aos resultados produtivos que as características dos substratos utilizados nesta pesquisa

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 117-125). Also available via the Internet.

A biopolpação consiste no biotratamento de madeira por fungos degradadores de lignina como etapa prévia à produção de polpa celulósica. De uma forma geral, as madeiras biotratadas facilitam os processos posteriores de polpação. Entretanto, ensaios anteriores que avaliaram a biopolpação em escala piloto mostraram que é difícil estabelecer os cultivos de basidiomicetos de interesse livre de bolores contaminantes, já que não é fácil controlar perfeitamente a assepsia durante a inoculação. Para contribuir com o avanço do processo de biopolpação, este trabalho avaliou os cultivos mistos de Ceriporiopsis subvermispora e Phanerochaete chrysosporium sobre madeira de Eucalyptus grandis e Eucalyptus urograndis em regimes de incubação em temperaturas variáveis e em condições não assépticas. A estratégia de iniciar os cultivos em temperatura mais elevada (37°C) e depois manter as culturas em temperaturas variáveis de 27°C e 37°C se mostrou eficiente para inibir o crescimento de contaminantes indesejáveis tanto nos cultivos mistos como nos individuais de cada espécie avaliada. Para avaliar o efeito do biotratamento da madeira numa etapa subsequente de polpação quimiotermomecânica (CTMP) foi feito um estudo preliminar de ajuste de variáveis de polpação por refinamento mecânico de cavacos pré-digeridos com licor alcalino contendo sulfito de sódio. Os dados mostraram que é possível simular o rendimento e as características fisico-mecânicas de polpas industriais empregando uma etapa de pré-digestão dos cavacos com 6% de Na2SO3 e 3% de NaOH a 120°C por 2 h, seguida de desfibramento e refino em refinador de discos. As curvas de refino nesse processo CTMP mostraram que os cavacos biotratados deram origem a polpas com 300 mL de Freeness (CSF) consumindo menos energia do que o observado para o refino da madeira controle. As economias de energia chegaram a 60% em alguns casos, porém não foram maximizadas pelo efeito sinérgico do cultivo misto dos dois basidiomicetos em questão. Experimentos adicionais foram desenvolvidos empregando as espécies fúngicas Pycnoporus sanguineus e Trametes versicolor que foram eficientes para competir com contaminantes mesmo a 27oC. Neste caso, as economias de energia no processo CTMP subsequente somente foram obtidas com tempos mais longos de biotratamento (30 dias) e ainda assim os valores obtidos foram inferiores àqueles obtidos com as madeiras biotratadas por C. subvermispora e P. chrysosporium. Também a combinação das espécies C. subvermispora e Pleurotus ostreatus foi avaliada. Neste caso havia informação prévia da literatura indicando um efeito sinérgico da ação das duas espécies no que diz respeito a secreção da enzima manganês-peroxidase (MnP) e na degradação de lignina. Os resultados corroboraram que os cultivos mistos de C. subvermispora e P.ostreatus proporcionam maior produção de MnP do que os cultivos individuais de cada espécie. Por outro lado, P. ostreatus foi ineficiente para promover a redução do consumo de energia no processo CTMP subsequente. Os cultivos mistos também não proporcionaram efeito superior àquele observado com o cultivo individual de C. subvermispora. / Biopulping involves the wood biotreatment by selected white-rot fungi as a pretreatment step of conventional pulping processes. In general, the biotreated wood facilitates the subsequent pulping processes. However, previous studies on pilot scale showed that the process is susceptible to contamination by molds when the inoculation and biodegradation steps are carried out under non-aseptic conditions. To contribute with the biopulping progress this study evaluated the use of mixed cultures of Ceriporiopsis subvermispora and Phanerochaete chrysosporium acting on Eucalyptus grandis and Eucalyptus urograndis wood under non aseptic conditions where incubation was performed at varied temperatures. The simple strategy of initiating the incubation at 37°C for 3 days followed by a non-controlled step where the temperature could oscillate in the range of 27°C to 37°C proved to be efficient to inhibit the growth of contaminants. To evaluate the wood biotreatment effect in a subsequent step of chemithermomechanical pulping (CTMP), a preliminary study to adjust pulping variables was performed. Wood chips were predigested with alkaline-sulfite liquor, fibrillated and refined in a disk refiner. It was possible to simulate the yield and physico-mechanical properties of industrial CTMP pulps using a pre-digestion stage with 6% of Na2SO3 and 3% of NaOH at 120°C for 2 h. The refing curves in the CTMP process showed that the biotreated chips required less energy to reach 300 mL of Freeness (CSF) in the pulps than energy required to refine the control wood chips. Energy savings reached 60% in some cases, but were not maximized by the eventual synergic effect of the mixed cultures of the two basidiomycetes. Additional experiments were developed using the fungal species Trametes versicolor and Pycnoporus sanguineus that were efficient to compete with contaminants even at 27°C. In this case, the energy savings in the subsequent CTMP process were obtained only after long biotreatment times (30 days) and these values were lower than those obtained with the biotreated wood by C. subvermispora and P. chrysosporium. The combination C. subvermispora and Pleurotus ostreatus was also evaluated. In this case, previous literature information indicated some synergic effect of the two species regarding secretion of manganese peroxidase (MnP) and lignin degradation. The results corroborated that the mixed cultures of C. subvermispora and P.ostreatus provided an increased production of MnP compared to the individual cultivation of each species. On the other hand, P.ostreatus was not efficient to promote energy savings in the subsequent CTMP process. The mixed cultures did not provide increased energy savings as compared with the individual biotreatment with C. subvermispora.

Thesis (Ph. D.) in Biological Sciences--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 148-166).

Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Basidiomycetous yeasts are found in a wide range of geographical areas ranging from tropical forests to desert regions. These yeasts are associated with different habitats such as soil, decaying vegetative debris, living plants and animals. Some may even be opportunistic human pathogens. In most of these habitats the yeasts may periodically be exposed to adverse conditions such as osmotic stress. Forty-one basidiomycetous yeast strains obtained from culture collections and isolated from nature were studied using various methods which includes the determination of different minimum water activities (aw; NaCl or sorbitol) for growth, survival in soil of varying moisture content, intracellular osmolytes accumulated and their release upon hypo-osmotic stress. The growth of most strains showed greater tolerance to NaCl than sorbitol at the same level of water activity. Interestingly, there were no basidiomycetous strains that showed growth below 0.90aw. 13C nuclear magnetic resonance (NMR) spectroscopy and high performance liquid chromatography (HPLC) was used to analyze the osmolytes accumulated by all the strains of basidiomycetous yeasts when grown at 0.95 aw (NaCl). Glycerol was the major solute accumulated intracellulary by all the yeasts. Arabitol, mannitol or trehalose was accumulated in addition to glycerol in most yeasts whereas a number of yeasts only accumulated glycerol when grown at reduced aw. However, Cryptococcus laurentii US 1F was an exception by accumulating three solutes intracellularly when grown at reduced water activity. When exposed to hypo-osmotic shock all three solutes were rapidly released from the cells. Cryptococcus hungaricus CBS 5421, Cryptococcus macerans CBS 2206 and Cryptococcus neoformans US I1 were further analyzed with 13C NMR spectroscopy to determine whether the type of osmolyte accumulated during different phases of growth at 0.95aw (NaCl) might change. No changes were observed as the same osmolytes were accumulated in all cases. Five yeast strains (C. neoformans US I1, Rhodotorula mucillaginosa CBS 5951, C. macerans CBS 2206T, Filobasidium floriforme CBS 6240 and Sporidiobolus salmonicolor CBS 5937) were analyzed by HPLC for osmolytes released when exposed to hypo-osmotic shock. The strains differed in the pattern of response of osmolyte release. Only three strains released most of their osmolytes rapidly within 5 min, while C. macerans CBS 2206T and R. muculaginosa CBS 5951 retained most of the osmolytes intacellularly. This suggests that there might be different mechanisms of osmolyte release in basidiomycetous yeasts. A few strains of basidiomycetous yeasts (C. neoformans US I1, R. mucilaginosa CBS 5951, C. laurentii 1F, C. macerans CBS 2206T, F. floriforme CBS 6240, C. neoformans CBS 0132, C. laurentii CBS 0139, S. salmonicolor CBS 5937 and Filobasidium capsuligenum CBS 4381) were grown in soil cultures of different field capacity (100%, 25%, 10% and 5%) and evaluated for their survival in this environment. All the strains grew at 100% field capacity. Strains R. mucilaginosa CBS 5951, F. floriforme CBS 6240 and F. capsuligeum CBS 4381 also showed growth in soil at 25% field capacity. However, strains C. neoformans US I1, C. laurentii US 1F, C. macerans CBS 2206T and C. laurentii CBS 0139 did not grow at this moisture content but survived up until the end of the experimental period. At lower soil moisture content (5% and 10% field capacity), the yeast strains either showed survival or decreased viability towards the end of the experimental period. Strain C. neoformans US I1, C. laurentii US 1F, C. macerans CBS 2206T and R. mucilaginosa CBS 5951 and F. floriforme CBS 6240 showed survival at both 5% and 10% field capacity. However, strain F. neoformans CBS 0132, C. laurentii CBS 0139, F. capsuligenum CBS 4381 and S. salmonicolar CBS 5937 showed a decrease in viability after either 2 or 5 days of incubation. No relationship could be found between the type and number of intracellular osmolytes accumulated when exposed to osmotic stress (0.95aw NaCl) and the ability to grow and survive in soil with lower moisture content. Similarly, the ability of the yeasts to grow and survive in soil with lower moisture content did not correlate with their minimum aw for growth in a liquid medium. It was speculated that other factors, such as the physico-chemical composition of the soil, may also play a role in the survival of a particular yeast species in soil. This study has shown that the responses of basidiomycetous yeasts to reduced aw are physiologically similar to the ascomycetous yeasts. The types of osmolytes accumulated are similar but the basidiomycetous yeasts appear to be more sensitive to reduced aw and they tolerate NaCl better than sorbitol whereas the ascomycetous yeasts tolerate high sugar environments better. This is in agreement with the environments where these yeasts are usually found. / AFRIKAANSE OPSOMMING: Basidiomisete giste word aangetref in ‘n wye reeks geografiese areas, wat strek vanaf tropiese woude tot woestynstreke. Hierdie giste word geassosieer met verskillende habitatte soos grond, verrottende vegetatiewe reste, lewende plante en diere. Sommige mag selfs opportunistiese menslike patogene wees. By meeste van hierdie habitatte mag giste periodies blootgestel word aan moeilike toestande soos osmotiese stres. Een-en-veertig basidiomisete gisrasse, verkry vanaf kultuurversamelings en geisoleer vanuit die natuur, was bestudeer met verskeie metodes, waaronder die bepaling van verskillende minimum water aktiwiteite (aw; NaCl of sorbitol) vir groei, droë massa bepalings, akkumulasie van intrasellulêre osmoliete, asook hul vrystelling met hipo-osmotiese stres. Meeste rasse het meer weerstand teen NaCl as sorbitol gehad by dieselfde vlak van wateraktiwiteit. Dit was interessant om op te let dat geen basidiomisete stamme groei onder 0.90aw getoon het nie. Beide 13C kern magnetiese resonansie (KMR) spektroskopie en hoë uitset vloeistof chromatografie (HUVC) was gebruik om alle opgehoopde osmoliete te analiseer vir alle basidiomisete gisrasse tydens groei tot by 0.95 aw (NaCl). Vir alle giste was gliserol die opgelosde stof wat die meeste intrasellulêr opgehoop het. Arabitol of mannitol of trehalose het saam met gliserol in meeste giste opgehoop, terwyl ‘n aantal giste slegs gliserol opgehoop het tydens groei by verlaagde aw. Cryptococcus laurentii US 1F was daarenteen ‘n uitsondering deurdat dit drie opgelosde stowwe intrasellulêr versamel het tydens groei by verlaagde wateraktiwiteit. Al drie hierdie opgelosde stowwe is uit die selle vrygesel na blootstelling aan hipo-osmotiese skok. Verdere 13C KMR spektroskopie analise was gedoen op Cryptococcus hungaricus CBS 5421, Cryptococcus macerans CBS 2206 en Cryptococcus neoformans US I1 om vas te stel of die tipe opgehoopde osmoliet tydens verskillende fases van groei by 0.95aw (NaCl) mag verander. Geen veranderinge was egter waargeneem aangesien dieselfde osmoliete in alle gevalle opgehoop het. Vyf gisrasse (C. neoformans US I1, Rhodotorula mucillaginosa CBS 5951, C. macerans CBS 2206T, Filobasidium floriforme CBS 6240 en Sporidiobolus salmonicolor CBS 5937) was geanaliseer deur HUVC vir osmolietvrystelling tydens blootstelling aan hipo-osmotiese skok. Die rasse het verskil in hul responspatroon van osmolietvrystelling. Slegs drie rasse het meeste van hul osmoliete vrygestel binne die eerste 5 minute, terwyl ander, C. macerans CBS 2206T en R. muculaginosa CBS 5951 meeste van hul osmoliete intrasellulêr teruggehou het. Dit dui daarop dat daar dalk verskillende meganismes van osmolietvrystelling in basidiomisete giste mag voorkom. Etlike basidiomisete gisrasse (C. neoformans US I1, R. mucilaginosa CBS 5951, C. laurentii 1F, C. macerans CBS 2206T, F floriforme CBS 6240, C. neoformans CBS 0132, C. laurentii CBS 0139, (B) S. salmonicolor CBS 5937, Filobasidium capsuligenum CBS 4381) was opgegroei in grondkulture van verskillende veldkapasiteit (100%, 25%, 10% en 5%) en ondersoek vir hul oorlewing in hierdie omgewing. Al die rasse kon groei by ‘n 100% veldkapasiteit. Die rasse R. mucilaginosa CBS 5951, F. floriforme CBS 6240 en F. capsuligeum CBS 4381 kon ook groei in grond met 25% veldkapasiteit. Alhoewel rasse C. neoformans US I1, C. laurentii US 1F, C. macerans CBS 2206T en C laurentii CBS 0139 nie kon groei by hierdie voginhoud nie, het hulle nog steeds oorleef tot aan die einde van die eksperimentele tydperk. By verlaagde grond voginhoud (5% en 10% veldkapasiteit) het die gisrasse of oorleef of ‘n verlaagde lewensvatbaarheid openbaar teen die einde van die eksperimentele prosedure. Die rasse C. neoformans US I1, C. laurentii US 1F, C. macerans CBS 2206T and R. mucilaginosa CBS 5951 en F. floriforme CBS 6240 het oorleef by beide 5% en 10% veldkapasiteit. Die rasse F. neoformans CBS 0132, C. laurentii CBS 0139, F. capsuligenum CBS 4381 en S. salmonicolar CBS 5937 het egter ‘n verlaging in lewensvatbaarheid getoon na ‘n periode van of 2 of 5 dae inkubasie. Geen ooreenstemming kon gevind word tussen die tipe en aantal intrasellulêre opgehoopde osmoliete nie na blootstelling aan osmotiese druk (0.95aw NaCl), asook hul vermoë om te groei en oorleef in grond met ‘n laer voginhoud. Terselfdertyd het die giste se vermoë om te groei en oorleef in grond met ‘n laer voginhoud nie ooreengestem met hul minimum aw vir groei in vloeibare groeimedium nie. Ter spekulasie kan ander faktore, soos die fisio-chemiese samestelling van die grond ook ‘n rol speel in die oorlewing van ‘n spesifieke gisspesie in grond. Hierdie studie het getoon dat basidiomisete giste se respons tot verlaagde aw fisiologies dieselfde is as vir askomisete giste. Alhoewel die tipe versamelde osmoliete identies was, wil dit voorkom asof basidiomisete giste meer sensitief teenoor ‘n verlaagde aw is, tesame met ‘n beter bestandheid teen NaCl as sorbitol, terwyl askomisete giste hoë suiker omgewings beter kan verdra. Dit is in ooreenstemming met die tipe omgewings waar hierdie giste gewoonlik voorkom.

Inaug.-Diss.--Erlangen. / Lebenslauf.

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