Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 506-540).

Made available in DSpace on 2014-06-12T15:53:04Z (GMT). No. of bitstreams: 2 arquivo5098_1.pdf: 917807 bytes, checksum: 66a5977f89199b35877ba7324a3e991f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2004 / Os fungos da ordem Mucorales têm se destacado pelo seu excelente potencial biológico na eliminação de contaminantes tóxicos do ambiente. Investigações foram realizadas no sentido de utilizar processos de biorremediação para a remoção de pireno por Rhizopus arrhizus. Estudos iniciais foram realizados para obtenção de um mutante fisiológico utilizando o teste de resistência ao pireno. O processo de germinação de esporos de R. arrhizus demonstrou que a presença de pireno (10 mg/L) nos meios de cultura testados BDA (Batata Dextrose e Ágar) e SAC (Peptona e Sacarose), acelerou o processo de germinação dos esporos das linhagens selvagem e mutante. O crescimento radial das linhagens de R. arrhizus foi inversamente proporcional ao aumento da concentração de pireno no meio de cultura. A linhagem mutante demonstrou melhor adaptação no meio de cultura contendo 50 mg/L de pireno, quando comparada à linhagem selvagem. Estudos subseqüentes foram realizados com os perfis de ácidos graxos e do sistema de ubiquinonas nas linhagens selvagem e mutante, mantidos no meio de cultura YMB contendo pireno (10 mg/L) e o controle (sem pireno). Os resultados com marcadores bioquímicos demonstraram alterações do percentual de ubiquinonas e do perfil de ácidos graxos. As duas linhagens apresentaram as Coenzimas Q7, Q9 e Q10. A linhagem selvagem demonstrou diferença no percentual da Coenzima principal Q9 (32%) em comparação com a linhagem mutante (8,4%). Uma redução discreta nos percentuais dos ácidos graxos também foi observada em ambas linhagens. A análise por cromatografia em fase gasosa (CG), evidenciou a presença dos ácidos graxos: oléico (18:1), palmítico (C16:0), palmitoléico (C16:1), esteárico (C18:0), linoléico (C18:2) e γ-linolênico (C18:3). Contudo, observou-se um aumento significativo dos percentuais de ácidos graxos saturados (C16:0) e (C18:0) e insaturados (C18:1) e (C18:2) na linhagem mutante, quando cultivada na presença de pireno (10mg/L). A análise através da cromatografia líquida de alta eficiência (CLAE) também demonstrou um aumento significativo no percentual da Coenzima Q9 na linhagem mutante, quando cultivada na presença de pireno (10 mg/L). Os processos de biorremoção/biossorção do pireno utilizando micélio inativado de R. arrhizus UCP402 e UCP402x, em ensaios a partir de um planejamento fatorial de dois níveis, demonstraram taxas elevadas de biossorção, 99,7% (linhagem selvagem) e 99.4% (linhagem mutante). No entanto, a cinética de remoção do pireno com o micélio vivo das linhagens selvagem e mutante, analisados através de CLAE confirmaram o excelente desempenho da biorremoção do pireno, correspondendo a 99,2% e 99,6% no meio YMB e 97,30% e 98,95% no meio SAC, respectivamente, para as linhagens selvagem e mutante. Os resultados obtidos com os processos de biorremoção/biossorção do pireno indicaram o grande potencial biotecnológico de R. arrhizus UCP 402x

Submitted by Fernanda Rodrigues de Lima (fernanda.rlima@ufpe.br) on 2018-08-16T22:15:29Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Hugo Marques Galindo.pdf: 653807 bytes, checksum: ae25da68525527ac9efaf13746cc334d (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-08-21T21:09:28Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Hugo Marques Galindo.pdf: 653807 bytes, checksum: ae25da68525527ac9efaf13746cc334d (MD5) / Made available in DSpace on 2018-08-21T21:09:28Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Hugo Marques Galindo.pdf: 653807 bytes, checksum: ae25da68525527ac9efaf13746cc334d (MD5) Previous issue date: 2016-03-04 / CNPq / A conversão da celulose em açúcares fermentáveis é realizada por um complexo enzimático de celulases capaz de hidrolisar as frações de celulose a seus monômeros de glicose. O objetivo deste trabalho foi avaliar o potencial de produção de celulases (endoglucanases e exoglucanases) por fungos Mucorales isolados a partir de solo do Bioma Caatinga. Inicialmente, 13 isolados de fungos foram avaliados quanto à capacidade de produção de celulases (CMCase e FPase) utilizando farelo de palha de milho como substrato através de fermentação em estado sólido (FES), durante 96 horas de cultivo a 35ºC. Foi detectada atividade enzimática em todos os isolados, sendo Rhizopus microsporus SIS 04 o isolado que apresentou maior atividade para ambas as celulases testadas (CMCase: 1,375 U/mL; FPase: 0,105 U/mL). Este isolado foi cultivado nas condições de fermentação determinadas através de planejamento fatorial utilizando como variáveis independentes: temperatura e umidade. A atividade de CMCase em 72 horas de incubação aumentou de 1, 375 para 1, 477 U/mL na temperatura de 38°C e umidade de 100%; e a atividade de FPase, em 72 horas de incubação aumentou de 0, 105 para 0, 118 U/mL, na temperatura de 38°C e umidade de 50%, notando-se que a temperatura foi a variável mais significativa para a atividade dessas celulases. A caracterização das enzimas produzidas pelo isolado Rhizopus microsporus SIS 04 demonstrou que o extrato enzimático com atividade de CMCase apresentou pH ótimo de 6 e temperatura ótima de 60°C, tendo sua atividade residual acima de 80% nos valores de pH: 4, 5, 6 e 7, e temperatura de 60°C; para atividade de FPase apresentou pH ótimo de 6 e temperatura ótima de 50°C, tendo sua atividade residual acima de 80% nos valores de pH: 5 e 6, e temperatura de 50 e 60°C. Evidenciando assim melhores resultados de atividade enzimática em temperaturas elevadas e valores de pH de ácido a levemente alcalino. / The conversion of cellulose to fermentable sugars is performed by an enzyme complex of cellulases able to hydrolyze the cellulose fraction their glucose monomers. The aim of this study was to evaluate the potential for cellulases production (endoglucanases and exoglucanases) by Mucorales fungi isolated from soil of Caatinga. Initially, thirteen fungal isolates were evaluated for capacity of cellulase production (CMCase and FPase) using corn husk bran as substrate in solid state fermentation (SSF) for 96 h incubation at 35°C. It was detected enzymatic activity in all isolates, but Rhizopus microsporus Sis 04 was the isolate that showed the highest activity for both tested cellulases (CMCase: 1.375 U/mL; FPase: 0.105 U/mL). This isolate was selected for optimization of fermentation conditions through a factorial design using as independent variables temperature and humidity. The CMCase activity at 72 h of incubation increased from 1.375 to 1.477 U/ml at 38°C and humidity of 100%; as well as the activity of FPase at 72 h of incubation increased from 0.105 to 0.118 U/ml, at temperature of 38°C and humidity of 50%, showing that the temperature was the most significant variable for the activity of these cellulases, where culture conditions were optimized. The characterization of cellulases produced by R. microsporus Sis 04 demonstrated that the enzymatic extract with CMCase activity showed optimum pH of 6 and optimum temperature of 60°C, and its residual activity above 80% in pH 4, 5, 6 and 7 and temperature of 60°C. However, FPase activity showed optimum pH of 6 and optimum temperature of 50°C, and its residual activity above 80% in pH 5 and 6, and temperature of 50 and 60°C. Thus, it was demonstrated that best results in enzymatic activity were reached at high temperatures and pH values from acid to slightly alkaline.

The development of sporangia and sporangioles is described in the mucoralean genera Choanephora, Blakeslea, Cunninghamella, and Mycotypha. The fine-structure of spore development is examined with transmission and scanning electron microscopy. Cytoplasmic cleavage in multisporous sporangia of Choanephora and Blakeslea involves fusion of cleavage vesicles to form a cleavage apparatus. Similar cleavage events occur in trisporous sporangioles of Blakeslea but the cleavage apparatus is oriented with the three longtitudinal "suture" lines of the sporangiole wall. The outer layer of spore walls is derived from a fibrous coating on the membranes of the cleavage apparatus. The inner wall layer is formed after deposition of the outer layer and is associated with the presence of granular vesicles in the spore cytoplasm. In monosporous sporangioles of Choanephora, Cunninghamella, and Mycotypha no cleavage apparatus is produced. Spores of all genera studied possess a bilayered wall with the outer layer demonstrating much greater electron-density than the inner layer. The relative thicknesses of the two wall layers varies greatly among genera. The outer layer is deposited in ridges and furrows in spores of Choanephora and Blakeslea. The structure of bipolar spore appendages is identical in these two genera. The ultrastructure of spines on sporangial surfaces is described. Spines on sporangioles of Cunninghamella exhibit a fine-structure different from that of Choanephora and Blakeslea. No spines are produced on spore walls of any of the genera studied. The identification of cellular components is examined using plastic-section histochemistry and light-microscopy. The cleavage apparatus initially contains carbohydrate which disappears as the spores mature. Bipolar spore appendages are shown to be composed of carbohydrate, with their bases staining for protein. In all spores, the cytoplasm shows intense staining for protein and weak staining for carbohydrates. Spore walls are difficult to stain with any of the procedures used. Based on the observed comparative ultrastructural development of asexual spores, recommendations and comments are made concerning the taxonomy of the Mucorales. / Science, Faculty of / Botany, Department of / Graduate

Made available in DSpace on 2014-06-12T15:02:38Z (GMT). No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os excrementos de herbívoros têm sido citados como um dos principais substratos para o isolamento de Zygomycetes. No entanto, existem poucos estudos relacionados ao conhecimento da composição de espécies desse grupo nesses substratos e à variabilidade genética existente entre Zygomycetes oriundos de diferentes regiões geográficas. Os objetivos desse trabalho foram: a) isolar e identificar Zygomycetes a partir de excrementos de herbívoros do Recife, Pernambuco, Brasil; b) comparar o número e a composição de espécies de Zygomycetes ocorrentes nos excrementos dos diferentes animais e entre os meses do ano; c) comparar as seqüências das regiões ITS do rDNA de Mucorales isolados com seqüências das mesmas espécies provenientes de diferentes regiões geográficas e depositadas no GenBank . A partir de coletas mensais (junho/2005 a maio/2006) de excrementos de anta, camelo, jumento-branco, cervonobre, waterbuck , lhama, cavalo e cutia, foram identificados 39 táxons de Zygomycetes distribuídos em 15 gêneros. Os resultados indicaram que a composição e o número de táxons variam para cada herbívoro e que a sazonalidade influencia a composição de espécies de Zygomycetes nos excrementos, mas não o número de táxons. Polimorfismo genético entre isolados de Cunninghamella elegans, Mycocladus blakesleeanus e Mucor circinelloides f. circinelloides foi constatado, enquanto os espécimes de Rhizopus oryzae foram incluídos em um mesmo clado. As quatro formas de M. circinelloides conhecidas formaram um grupo, não sendo possível a diferenciação genética entre as mesmas com a metodologia utilizada

Made available in DSpace on 2014-06-12T15:52:27Z (GMT). No. of bitstreams: 2 arquivo5008_1.pdf: 1316779 bytes, checksum: 4ac90091b5c7e9c1665a98b18c8fd9cd (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / A via microbiológica de produção de carotenóides de interesse comercial, quando comparada à contrapartida oriunda de síntese química, vem alcançando progressiva aceitação, expressa por uma duplicação do porte de mercado a cada quinquênio. De um modo geral, observa-se que os fungos apresentam um relevante potencial biotecnológico para a produção de carotenóides, uma vez que acumulam pigmentos durante o crescimento micelial. Neste trabalho a presença de astaxantina, β-caroteno e licopeno foi investigada em três espécies do Gênero Mucor (M. circinelloides, M. javanicus e M. racemosus) e duas espécies do Gênero Cunninghamella (C. bertholletiae e C. elegans). Através da análise espectrofotométrica (UV-visível) e por cromatografia líquida de alta eficiência (CLAE) constatou-se que dentre as cinco amostras investigadas as concentrações tanto de astaxantina (19,8 μg/g) como de β- caroteno (13,5 μg/g) foram mais altas no micélio de M. javanicus. O licopeno não foi detectado em nenhuma amostra. Surpreendentemente, a presença de astaxantina foi pela primeira vez observada em uma espécie de Mucor. O teor de astaxantina encontrado a partir de M. javanicus abriu perspectivas para a maximização dos rendimentos. Neste sentido, fatores, nutricionais e físicos, implicados no crescimento dos microrganismos e na produção de carotenóides, foram alterados e combinados através de planejamentos fatoriais completos e fracionários, buscando a localização da região de máxima produção. A otimização seqüencial do processo permitiu o aumento dos rendimentos de 145,9 para 1297,0 μg/L, confirmando o potencial de M. javanicus como fonte de astaxantina

Nas últimas décadas, tem sido relatado o aumento de casos de infecções fúngicas invasivas por agentes oportunistas, tais como Aspergillus spp., Fusarium spp. e fungos da ordem Mucorales, em pacientes hospitalizados, particularmente os imunocomprometidos. Como os sintomas são frequentemente inespecíficos, esses patógenos não são identificados inicialmente como agentes causais. Além disso, muitas vezes o diagnóstico só é estabelecido em estágios tardios da infecção, pois as metodologias diagnósticas de rotina, como cultura e microscopia, apresentam limitações caracterizadas, sobretudo, por baixa sensibilidade e especificidade. Os métodos moleculares, incluindo as amplificações de material genômico por PCR, em tecidos a fresco e parafinados, têm sido mais aplicados para a melhoria na detecção e identificação desses patógenos. A técnica de PCR em tempo real apresenta a vantagem de fornecer resultados com rapidez e elevada sensibilidade, além de minimizar os riscos de contaminação ambiental das amostras. Para aprimorar o conhecimento sobre a eficácia desta técnica na detecção e identificação dos patógenos, neste estudo foram utilizados camundongos da linhagem BALB/c para o desenvolvimento de modelos de infecção invasiva por Aspergillus fumigatus, Rhizopus arrhizus e Fusarium solani. Após inoculação dos fungos por via intravenosa, os órgãos (pulmão, fígado, rins, cérebro e coração) foram retirados para realização dos exames de cultura, histopatologia, PCR semi-nested e PCR em tempo real. As culturas foram realizadas em ágar Sabouraud dextrose e incubadas por 3 a 5 dias à temperatura ambiente. Para as análises histopatológicas, uma parte dos órgãos foi emblocada em parafina e cortes foram submetidos às colorações por hematoxilina-eosina e Gomori-Grocott. Para as análises moleculares, foram realizadas clonagens dos amplicons obtidos com os mesmos primers gênero-específicos (Aspergillus spp. e Fusarium spp.) e ordem-específicos (mucoráceos) empregados nas reações de PCR. Os clones foram empregados na técnica de PCR em tempo real para avaliação da sensibilidade analítica dos ensaios e como controles positivos. Os tecidos a fresco e parafinados foram submetidos a extrações de DNA, e as amostras foram avaliadas por PCR do tipo semi-nested, e por PCR em tempo real, empregando-se os primers gênero e ordem-específicos. Após 48-72 horas, observou-se crescimento fúngico nas culturas, porém a identificação macroscópica foi possível somente após 96 horas. Nos exames histopatológicos foram observadas presença de estruturas fúngicas e alterações na morfologia tecidual, confirmando a disseminação da infecção nos três modelos experimentais. Os dois métodos de PCR (convencional e tempo real) empregando os primers para Aspergillus e mucoráceos demonstraram 100% de especificidade. Além disso, os primers para mucoráceos amplificaram amostras de DNA dos gêneros Rhizopus, Mucor e Lichtheimia, confirmando serem ordem-específicos. Por outro lado, os testes moleculares com emprego de diversos primers de Fusarium apresentaram reatividade cruzada, principalmente com amostras de DNA de Aspergillus e Rhizopus. O limiar de detecção (LD) das PCR semi-nested para Aspergillus e Rhizopus foi de 50 fentogramas de DNA, enquanto na PCR em tempo real o LD foi de 20 fentogramas de DNA e 2x102 plasmídios/ul. Os dois métodos moleculares detectaram DNA de Aspergillus e Rhizopus, em 100% das amostras de tecido a fresco e parafinado, corroborando com os resultados de cultura e histopatologia. Os resultados do estudo demonstraram que a PCR em tempo real foi capaz de detectar e diferenciar Aspergillus e Rhizopus nos tecidos a fresco e parafinados, com 100% de especificidade e maior sensibilidade analítica quando comparada à PCR semi-nested. Entretanto, os resultados obtidos com diversos primers de Fusarium utilizados nos ensaios de PCR foram inconsistentes em relação à especificidade das amplificações. A PCR em tempo real constituiu um método rápido para diagnosticar, com acurácia, aspergilose e mucormicose em tecidos, podendo ser implementada como alternativa na rotina diagnóstica de laboratórios de patologia ou microbiologia. Por outro lado, a técnica apresentou baixa especificidade com os primers de Fusarium selecionados neste estudo. Outras sequências gênicas deste fungo deverão ser avaliadas na técnica molecular para se atingir resultados precisos / Increase of invasive fungal infections by opportunistic agents, such as Aspergillus sp., Fusarium sp. and fungi from the order Mucorales, in immunocompromised patients has been reported in the last decades. As the symptoms are often non-specific, diagnosis are only established in late stages of infection. Routine diagnostic methodologies, such as culture and direct microscopy, have limitations due to their low sensitivity and specificity. Molecular methods, including amplifications of nucleic acids by PCR in fresh and paraffined tissues, have been more frequently applied to improve the detection and identification of these pathogens. The real-time PCR (qPCR) technique has the advantage of providing fast results with high sensitivity, as well as minimizing the risks of environmental contamination of the samples. This study aimed to evaluate the effectiveness of this technique for detection and discrimination of the fungal pathogens in tissues taken from BALB/c mice intravenously inoculated with Aspergillus fumigatus, Rhizopus arrhizus and Fusarium solani. The organs (lung, liver, kidneys, brain and heart) were removed from animals and analysed by culture, histopathology, semi-nested PCR and qPCR. Recombinant plasmid clones containing small sequences of Aspergillus, Fusarium and mucoraceous were used to draw qPCR standard curves and to evaluate the analytical sensitivity of the assays. The fresh and paraffined tissues were submitted to DNA extractions, and samples were evaluated by semi-nested PCR and qPCR with genus-specific primers for Aspergillus and Fusarium, and order-specific primers for mucoraceous. Cultures were positive for all fresh tissue samples. Presence of typical fungal structures and alterations in tissue morphology were observed in the histopathological examinations, confirming the dissemination of infection in the three experimental models. Both PCR assays employing Aspergillus and mucoraceous primers demonstrated 100% specificity. On the other hand, molecular tests using at least six different Fusarium primers showed cross reactivity, mainly with Aspergillus and Rhizopus DNA samples. The limit of detection (LD) of the semi-nested PCR for Aspergillus and Rhizopus was 50 femtograms of DNA, while for the qPCR it was 20 femtograms of DNA, and 2x102 plasmids/?l. Both molecular methods detected Aspergillus and Rhizopus DNA in 100% of fresh and paraffined tissue samples, corroborating the results with cultures and histopathology. The results of the study demonstrated that qPCR assay was able to detect and differentiate Aspergillus and Rhizopus in fresh and paraffined tissues, with 100% of specificity and higher analytical sensitivity when compared to semi-nested PCR assay. However, the results obtained with several Fusarium primers in the PCR assays were inconsistent regarding specificity of the amplifications. Real-time PCR assay is a fast and accurate method to diagnose aspergillosis and mucormycosis in tissues, and could be implemented as an alternative tool for diagnostic routine in pathology or microbiology laboratories. On the other hand, the technique showed low specificity with the Fusarium primers selected in this study. Other gene sequences should be evaluated by PCR assays techniques to achieve accurate results

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Mucoralean fungi are mostly saprotrophs that are frequently encountered in soil habitats. Using an isolation temperature of circa 25°C, other workers obtained these fungi from a wide diversity of geographical areas in southern Africa. However, it is known that psychrotolerant mucoralean fungi, able to grow at 25°C as well as at 5°C, occur in pristine Alti Mountain Grassland. Nothing is known about the diversity of these psychrotolerant soil fungi in other vegetation types of South Africa. Consequently, in this study, the psychrotolerant fungal taxa and numbers in soil from a vineyard and from pristine Mountain Fynbos were determined using an incubation temperature of 4°C and a complex isolation medium. The latter contained agar, malt extract, peptone, yeast extract, penicillin and streptomycin sulphate. Soil samples were analysed in late summer, autumn and mid-winter. It was found that, for the samples taken in late summer and autumn, the diversity of mucoralean species in the soil differed between fynbos and vineyard. In winter however, no significant difference was detected between the Shannon's diversity indices of mucoralean species in the soil samples taken from the two habitats. It was found that in both soil types, the percentage mucoralean fungi on the plates increased from summer to winter. In addition, the numbers of detectable Morlierella subgenus Morlierella on the plates were higher in winter than in late summer. The diversity of mucoralean species obtained during winter in fynbos and vineyard soil was significantly less than the diversity of these species in Alti Mountain Grassland soil. To determine if the Morlierella subgenus Morlierella isolates from the fynbos and vineyard soil, and those obtained from Alti Mountain Grassland, differ in the ability to grow at low temperatures, the radial growth rate on malt extract agar at 4°C and BOC was determined for each isolate. The results indicate that not only did seasonal changes occur in the taxa within Morlierella subgenus Morlierella, but that the isolates dominating the soil in different seasons also differed in the ability to grow at low temperatures. The percentage of isolates that had reached greater colony diameters after B days of incubation at 4°C, was higher for the isolates obtained in the cold wet month of July than for those obtained in the warmer dryer month of February. Similar results were obtained with the radial growth experiments conducted at BOC. The Morlierella subgenus Morlierella isolates obtained in winter from fynbos and vineyard soil showed less variation in low temperature growth rate than the isolates of this taxon obtained in winter from Alti Mountain Grassland soil during a previous study. This variation corresponds to the greater number (20) of Morlierella subgenus Morlierella species found in the grassland soil. Altogether only seven species of this subgenus was detected during the present study in the fynbos and vineyard soil samples. It was speculated that this difference in diversity between the fynbos and vineyard isolates, and the grassland isolates obtained in a previous study, might have been as a result of differences in the habitat or the enumeration methods used. The phylogenetic relationship between different psychrotolerant isolates of Morlierella subgenus Morlierella originating from the soil of the fynbos, vineyard and Alti Mountain Grassland, was subsequently determine through comparison of ITS regions, within ribosomal RNA repeats. Consequently, 45 psychrotolerant Morlierella subgenus Morlierella isolates originating from the three soil habitats was compared on the basis ITS 1 nucleotide sequence composition and radial growth rate at 4°C. Phylogenetic analyses showed that the isolates could be grouped into two clusters correlating with the ability to grow at low temperatures. Each cluster was further subdivided into two subgroups. It was found that except for one subgroup and the reference strain occurring in another subgroup, all the subgroups contain isolates originating from a single soil habitat. Therefore, the ITS 1 sequence of these fungi seems to indicate the original habitat and ability to grow at low temperatures. This correlation of the ITS sequence with the ecological habitat of a fungus has also been observed by other workers for other fungal groups. / AFRIKAANSE OPSOMMING: Mucoraliese fungi is meestal saprotrofe wat dikwels in grondhabitatte aangetref word. Deur gebruik te maak van 'n isolasietemperatuur van circa 25°C, het ander werkers dié fungi van 'n wye verskeidenheid geografiese gebiede in suidelike Afrika verkry. Dit is egter bekend dat die psigrotolerante mucoraliese fungi, wat in staat is om by 2SoC en ook by SaC te groei, in ongeskonde Alti Berg-Grasland voorkom. Niks is egter bekend oor die diversiteit van dié psigrotolerante grondfungi in ander veldtipes van suidelike Afrika nie. Die psigrotolerante fungustaksa en -getalle in grond van 'n wingerd en van ongeskonde Berg Fynbos is gevolglik in dié studie bepaal deur gebruik te maak van 'n inkubasietemperatuur van 4"C en 'n komplekse isolasiemedium. Laasgenoemde het agar, moutekstrak, peptoon, gisekstrak, penisillien en streptomisiensulfaat bevat. Grondmonsters is in die laatsomer, herfs en midwinter geanaliseer. Daar is 'n verskil gevind tussen die diversiteit van die mucoraliese spesies in die grond van fynbos en dié van wingerd in die monsters wat in die laatsomer en midwinter geneem is. In die winter is daar egter geen beduidende verskil gevind tussen die Shannon diversiteitsindekse van mucoraliese spesies in die grondmonsters wat uit die twee habitatte getrek is nie. In albei grondtipes is daar gevind dat die persentasie mucoraliese fungi op die plate toegeneem het van somer tot winter. Daarby was die aantal waarneembare Morlierella subgenus Morlierella op die plate meer in die winter as in die laatsomer. Die diversiteit van mucoraliese spesies wat in die winter uit fynbos- en wingerdgrond verkry is, was beduidend minder as die diversiteit van dié spesies in Alti Berg-Grasland grond. Om te bepaal of die Morlierella subgenus Morlierella isolate van die fynbos- en wingerdgrond en dié van Alti Berg-Grasland van mekaar verskil ten opsigte van hul vermoë om by lae temperature te groei, is die radiale groeitempo op moutekstrak by 4"C en aoc vir elke isolaat bepaal. Die resultate dui aan dat daar nie alleen seisoenale veranderinge in die taksa binne Morlierella subgenus Morlierella voorkom nie, maar dat die isolate wat tydens verskillende seisoene uit die grond verkry is, ook ten opsigte van hul groeivermoë by lae temperature van mekaar verskil. Die persentasie isolate wat groter kolonie diameters bereik het ná B dae inkubasie by 4°C, was hoër vir die isolate van die koue, nat Juliemaand as vir dié wat in die warmer en droër Februariemaand verkry is. Soortgelyke resultate is verkry met radiale groei-eksperimente wat by BOC gedoen is. Die MortierelIa subgenus MortierelIa isolate wat in die winter uit fynbos- en wingerdgrond verkry is, het In kleiner variasie in hul groeitempo by lae temperature getoon as die isolate in dié takson wat tydens 'n vorige studie in die winter uit Alti Berg-Grasland grond verkry is. Dié variasie stem ooreen met die groter aantal (20) MortierelIa subgenus MortierelIa spesies wat in die graslandgrond gevind is. Slegs sewe spesies van dié subgenus is gedurende die huidige studie in die fynbos- en wingerdgrondmonsters waargeneem. Daar is gespekuleer dat dié verskil in diversiteit tussen die fynbos- en wingerdisolate en die graslandisolate van die vorige studie die gevolg mag wees van verskille tussen die habitat of die enumerasiemetodes wat gebruik is. Die filogenetiese verwantskap tussen verskillende psigrotolerante isolate van MortierelIa subgenus MortierelIa uit die grond van die fynbos, wingerd en Alti Berg-Grasland, is vervolgens bepaal deur 'n vergelyking van interne getranskribeerde spasieerder (ITS) areas, binne ribosomale RNS herhalings. Daar is gevolglik 45 psigrotolerante MortierelIa subgenus MortierelIa isolate uit die drie grondhabitatte met mekaar vergelyk op grond van die basis ITS 1 nukleotied opeenvolgingsamestelling en radiale groeitempo by 4°C. Filogenetiese analises het die isolate in twee groepe verdeel op grond van hul vermoë om by lae temperature te groei. Elke groep is verder in twee subgroepe verdeel. Daar is gevind dat behalwe vir een subgroep en die verwysingstam wat in 'n ander subgroep voorgekom het, elkeen van die subgroepe bestaan het uit isolate wat van 'n enkele grond habitat verkry is. Dit wil dus voorkom of die ITS 1 opeenvolging van dié fungi 'n aanduiding gee van die oorspronklike habitat en die vermoë om by lae temperature te groei. Dié korrelasie tussen die ITS opeenvolging en die ekologiese habitat van 'n fungus is ook deur ander werkers vir ander fungusgroepe waargeneem.

Fruit and vegetables are often spoilt during storage, handling and transportation due to microorganisms. The common spoilage causes are fungi within the order Mucorales, the largest order of the class Zygomycetes. Such spoilage can result in reduced food supplies, poor quality and severe losses to producers and traders. The study was to investigate the type of Mucorales prevalent in various commodities and in a particular market than others. Fifty infected papaya, peaches and strawberries were collected at five occasions from large, medium and small markets. Isolation was done aseptically in a biosafety cabinet. Mucorales were identified morphologically, through culture based tests and molecular techniques. Mucorales isolated are Rhizopus stolonifer, Mucor circinelloides and Mucor racemosus. Mucorales were isolated at a higher rate in samples collected from the small market than other two markets. Spoilage in all three markets is assumed to be influenced by lack of modified temperatures in the storage room. / Life and Consumer Sciences / M. Sc. (Life Sciences)

Fruit and vegetables are often spoilt during storage, handling and transportation due to microorganisms. The common spoilage causes are fungi within the order Mucorales, the largest order of the class Zygomycetes. Such spoilage can result in reduced food supplies, poor quality and severe losses to producers and traders. The study was to investigate the type of Mucorales prevalent in various commodities and in a particular market than others. Fifty infected papaya, peaches and strawberries were collected at five occasions from large, medium and small markets. Isolation was done aseptically in a biosafety cabinet. Mucorales were identified morphologically, through culture based tests and molecular techniques. Mucorales isolated are Rhizopus stolonifer, Mucor circinelloides and Mucor racemosus. Mucorales were isolated at a higher rate in samples collected from the small market than other two markets. Spoilage in all three markets is assumed to be influenced by lack of modified temperatures in the storage room. / Life and Consumer Sciences / M. Sc. (Life Sciences)