Dissertations / Theses on the topic 'Microbial diversity'
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Pagaling, Eulyn. "Microbial diversity of Chinese lakes." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/7662.
Full textSanal, Zeynep. "Microbial diversity in evaporite brines." Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/29800.
Full textKarlinska-Batres, Klementyna. "Microbial diversity of coralline sponges." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-179567.
Full textO'Flaherty, S. M. "Microbial diversity in contaminated soil." Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274042.
Full textXue, Peipei. "Soil Microbial Diversity: Relating Microbial Distributions to Soil Functions." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/28830.
Full textBaumgarte, Susanne. "Microbial diversity of soda lake habitats." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968508480.
Full textEdlund, Anna. "Microbial diversity in Baltic Sea sediments /." Uppsala : Dept. of Microbiology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200726.pdf.
Full textEren, Ahmet. "Assessing Microbial Diversity Through Nucleotide Variation." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/1307.
Full textOrd, Victoria June. "Modelling microbial diversity in Antarctic soils." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2726.
Full textDurbin, Alan Teske Andreas. "Microbial diversity of oligotrophic marine sediments." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2627.
Full textTitle from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Marine Sciences." Discipline: Marine Sciences; Department/School: Marine Sciences.
Ghezzi, Daniele <1989>. "Microbial diversity and metabolic potential in caves." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9467/1/Ghezzi_Daniele_tesi.pdf.
Full textMoodley, Kamini. "Microbial diversity of Antarctic Dry Valley mineral soil." Thesis, University of the Western Cape, 2004. http://etd.uwc.ac.za/index.php?module=etd&.
Full textCloete, Melissa. "Microbial diversity of the Namib Desert salt pans." University of the Western Cape, 2015. http://hdl.handle.net/11394/5230.
Full textSalt pans are a characteristic feature of many dry deserts. The microbial communities inhabiting salt pans are thought to be particularly complex and are generally dominated by halophilic microorganisms. Although saline pools are frequently found within the hyper-arid Namib Desert, the microbial communities of these saline sites have been scarcely investigated. The aim of the present study was to characterise the archaeal, bacterial and cyanobacterial diversity inhabiting these extreme saline pools using three culture independent molecular techniques (DGGE, T-RFLP and 16S rRNA clone libraries). The physiochemical results, mainly the conductivity readings recorded from the sampling sites, indicated that the Gobabeb (103.0mS/cm) region was less saline than the two Swakopmund [(Sps01) (150.0mS/cm) and Sps02 (180.0mS/cm)] sites. Results obtained from DGGE and T-RFLP data were in agreement for both bacterial and cyanobacterial analysis indicating that the Gobabeb site was more diverse than the two Swakopmund sites (Sps01 and Sps02). In comparison, the archaeal community profiles for DGGE and T-RFLP analysis were in agreement illustrating that the archaeal community were more abundant in the two extreme Swakopmund saline sites. Phylogenetic data obtained from 16S rRNA gene clone libraries identified halophilic phylotypes (Rhodothermaceae, Idiomarinaceae Puniceicoccaceae and Cyanobacteria/Chloroplast, Family VII) normally associated with salt rich sites. In addition, a large number of unclassified taxa were identified. To conclude, the study highlighted the presence of a rich microbial diversity present within the salt pans of the Namib Desert and establishes a platform for future investigations.
National Research Foundation
Handley, Kim Marie. "Microbial diversity and respiratory processes in hydrothermal sediment." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492237.
Full textSlabbert, Etienne. "Microbial diversity of soils of the Sand fynbos." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/4082.
Full textThe soil environment is thought to contain a lot of the earth’s undiscovered biodiversity. The aim of this study was to understand the extent of microbial diversity in the unique ecosystem of the Western Cape’s fynbos biome. It is known that many processes give rise to this immense microbial diversity in soil. In addition the aim was to link microbial diversity with the soils physio-chemical properties as well as the plant community’s structure. Molecular methods especially automated ribosomal intergenic spacer analysis (ARISA) was used in the study. The most important property of environmental DNA intended for molecular ecology studies and other downstream applications is purity from humic acids and phenolic compounds. These compounds act as PCR inhibitors and need to be removed during the DNA extraction protocol. The fist goal in the study was to develop an effective DNA extraction protocol by using cationic locculation of humic acids. The combination of cationic flocculation with CuCl2 and the addition of PVPP and KCl resulted in a high yield of DNA, suitable for PCR amplification with bacterial and fungal specific primers. Determining the reproducibility and accuracy of ARISA and ARISA-PCR was important because these factors have an important influence on the results and effectiveness of these techniques. Primer sets for automated ribosomal intergenic spacer analysis, ITS4/ITS5, were assessed for the characterization of the fungal communities in the fynbos soil. The primer set delivered reproducible ARISA profiles for the fungal community composition with little variation observed between ARISAPCR’s. ARISA proved useful for the assessment and comparison of fungal diversity in ecological samples. The soil community composition of both fungal and bacterial groups in the Sand fynbos was characterized. Soil from 4 different Sand fynbos sites was compared to investigate diversity of eubacterial and fungal groups at the local as well as a the landscape scale. A molecular approach was used for the isolation of total soil genetic DNA. The 16S-23S intergenic spacer region from the bacterial rRNA operon was amplified when performing bacterial ARISA from total soil community DNA (BARISA). Correspondingly, the internal transcribed spacers, ITS1, ITS2 and the 5.8S rRNA gene from the fungal rRNA operon were amplified when undertaking fungal ARISA (F-ARISA). The community structure from different samples and sites were statistically analysed. ARISA data was used to evaluate different species accumulation and estimation models for fungal and bacterial communities and to predict the total community richness. Diversity, evenness and dominance were the microbial communities were used to describe the extent of microbial iversity of the fynbos soils. The spatial ordination of the bacterial and fungal species richness and diversity was considered by determining the species area relationship and beta diversity of both communities. The correlation between the soil physio-chemical properties was determined. The plant community structure data was correlated with the fungal and the bacterial community structure. The results indicated that bacterial species numbers and diversity were continually higher at the local scale. Fungi however showed higher species turnover at the landscape scale. Bacterial community structure showed stronger links to the plant community structure whereas the fungi community structure conformed to spatial separation patterns. To further investigate the diversity of soil microbes the potential of genus specific primes was investigated. The genus Penicillium is widespread in the soil environment and the extent of its diversity and distribution is however not. For this reason Penicillium was chosen as a model organism. To expand the insight into the diversity of Penicillium species in the fynbos soil ecosystem, a rapid group specific molecular approach would be useful. Penicillium specific primers targeting the 18S rRNA ITS gene region were evaluated. Fungal specific primers ITS4 and ITS5, targeting the internal transcribed region (ITS) were used to target Penicillium specific in the soil sample. Nested PCR, using primer Pen-10 and ITS5, was then utilized to target Penicillium species specifically. The discrimination of Penicillium species was possible due to length heterogeneity of this gene region. Eight different peaks was detected in the soil sample with ARISA and eight different species could be isolated on growth media. The technique proved useful for the detection and quantification of Penicillium species in the soil.
Pelz, Kirsten Suzanne. "Mosquito production and microbial diversity in container habitats." Diss., Connect to online resource - MSU authorized users, 2008.
Find full textTitle from PDF t.p. (viewed on July 7, 2009) Includes bibliographical references (p. 185-195). Also issued in print.
Sanz, Sáez Isabel. "Contribution of marine heterotrophic cultured bacteria to microbial diversity and mercury detoxification." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671617.
Full textLos océanos contienen aproximadamente un total de 10^29 células microbianas. Las bacterias marinas son responsables de la mayor parte de la respiración que se produce en el océano y son esenciales en los ciclos biogeoquímicos de la Tierra. Estudiar la diversidad bacteriana de los ecosistemas marinos y tener acceso a los genomas mediante estudios dependientes e independientes de cultivo es importante para descifrar el potencial metabólico de las bacterias marinas. Los cultivos nos aportan información sobre la fisiología bacteriana, ecología y contenido genómico, pero la mayoría de los esfuerzos en aislar bacteria marinas provienen de la zona fótica del océano, dejando las profundidades marinas menos exploradas. En esta tesis, técnicas estándar de cultivo han permitido crear una colección marina de bacterias heterótrofas (MARINHET), compuesta por más de 2000 aislados, recuperados de varias regiones oceanográficas, de varias profundidades (superficie, mesopelágico y batipelágico), y cubriendo varias estaciones y años. El Capítulo 1 describe su taxonomía, diversidad filogenética y biogeografía y revela que un 37% de las cepas son 100% idénticas en la secuencia parcial del gen ribosomal 16S (16S rRNA) entre la zona fótica (superficie) y afótica (mesopelágico y batipelágico). Además, hemos identificado Alteromonas y Erythrobacter entre los géneros marinos heterótrofos más comunes que recuperamos en cultivo usando un medio marino estándar. Las técnicas tradicionales de cultivo generalmente solo recuperan una fracción pequeña de las comunidades bacterianas naturales, fenómeno conocido como ‘la gran anomalía de recuento en placa’ y muchas de las cepas que se aíslan pertenecen a la biosfera rara. Sin embargo, no conocemos si estos patrones, normalmente descritos para las bacterias de superficie, también se aplican en las profundidades. En el Capítulo 2 he combinado resultados obtenidos mediante técnicas dependientes e independientes de cultivo comparando las secuencias del 16S rRNA de la colección MARINHET contra los fragmentos de secuenciación masiva del 16S rRNA (de amplicones y metagenomas), obtenidos de muestras globalmente distribuidas y de diferentes profundidades. Una mayor proporción de las bacterias del océano profundo son cultivables y una fracción importante de los aislados tiene preferencia a un estilo de vida adherido a partículas. Además, confirmamos que el dogma ‘menos del 1% de las bacterias son cultivables’ deber ser revisado ya que encontramos variabilidad en las muestras de profundidad, donde hasta un 3% de las células se han podido aislar. Los aislados bacterianos son un excelente material para aplicaciones biotecnológicas, como la biorremediación de zonas marinas contaminadas. El mercurio es un metal pesado tóxico y su forma más peligrosa, el metilmercurio (MeHg), se bioacumula en la cadena trófica marina. No obstante, se conoce muy poco la tolerancia de bacterias marinas frente al mercurio o la fisiológia de aquellas cepas que codifican los genes de resistencia (operón mer). El Capítulo 3 describe los resultados del mapeo funcional de los genes merA y merB, clave en la detoxificación, en una fracción de la colección MARINHET. Nos centramos en dos géneros marinos, con un potencial genético para la degradación del mercurio previamente descrito en la literatura, como son Alteromonas y Marinobacter. Desvelamos que los genes merAB están ampliamente distribuidos en diferentes regiones oceanográficas y en varias profundidades. Adicionalmente, hemos seleccionado una cepa de Alteromonas mediterranea para futuros estudios de biorremediación debido a su alta tolerancia y capacidad de degradación de diferentes formas de mercurio.
The world’s oceans sustain the life for an estimated total of 10^29 microbial cells. Marine bacteria are responsible for most part of the ocean respiration and are key in most biogeochemical cycles of the Earth. Accordingly, the study of the bacterial diversity present in different marine ecosystems is essential, and having access to their genomes through isolation or genomic centric studies is important to decipher their metabolic potential. Isolation of marine microorganisms is fundamental to gather information about their physiology, ecology and genomic content. To date, most of the bacterial isolation efforts have focused on the photic ocean leaving the deep ocean less explored. In this thesis, standard plating techniques allowed to create a marine culture collection of heterotrophic bacteria (MARINHET). More than 2000 isolates were retrieved from samples collected from a variety of oceanographic regions, from different depths including surface, mesopelagic and bathypelagic waters, and also covering different seasons and years. Chapter 1 describes the taxonomy, the phylogenetic diversity and the biogeography of culturable heterotrophic marine bacteria, and reveals that an important percentage of the strains (37%) are 100% identical in their partial 16S rRNA gene between photic and aphotic layers. In addition, we identified Alteromonas and Erythrobacter genera as the most frequently retrieved heterotrophic bacteria from the ocean in standard marine agar medium. It is a long-standing observation that traditional culture techniques only retrieve a small fraction of the microbial diversity found in natural environments including marine ecosystems, what is known as ‘the great plate count anomaly’. In addition, most of the retrieved isolates belong to the so-called rare biosphere. However, we do not know if these patterns, usually described for bacteria living in the photic ocean, also apply for the deep ocean bacteria. In Chapter 2 of this thesis, I combined results from culture-dependent and -independent techniques by comparing the 16S rRNA partial sequences of the MARINHET isolates with 16S rRNA amplicon Illumina TAGs (16S iTAGs) and metagenomic TAGs (miTAGs) from surface, mesopelagic and bathypelagic samples globally distributed. A high proportion of bacteria inhabiting the deep ocean could be retrieved by pure culture techniques and a significant fraction of the isolates preferred a lifestyle attached to particles. Additionally, I revised the axiom that ‘less than 1% of bacteria can be cultured’, finding variability between mesopelagic and bathypelagic samples, where up to 3% of the cells could be cultured. Bacterial isolates also represent a valuable genetic reservoir for biotechnology applications, such as bioremediation strategies of marine polluted environments. Mercury is one of the most toxic heavy metals in the planet and its most dangerous form, methylmercury (MeHg), is being bioaccumulated in the marine food web. However, little is known about the tolerance capacity and phenotypic characterization of marine bacteria codifying the mercury resistance operon (mer operon). Chapter 3 describes the functional screening of merA and merB genes, which are key in the mercury detoxification process, in well know marine genera with described genetic potential for mercury detoxification, such as Alteromonas and Marinobacter. I reported that the merAB genes from these two genera are widely distributed in different oceanographic regions and depths. In addition, I selected a promising candidate, phylogenetically affiliated to Alteromonas mediterranea, for future bioremediation studies due to its high tolerance and degradation ability of different mercury forms.
Universitat Autònoma de Barcelona. Programa de Doctorat en Microbiologia
Luo, Chengwei. "Development of algorithms for metagenomics and applications to the study of evolutionary processes that maintain microbial biodiversity." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47730.
Full textChatzinotas, Antonis. "Assessing microbial diversity in terrestrial environments using molecular methods /." [S.l.] : [s.n.], 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13606.
Full textWang, Chunxiao. "New approaches to estimate microbial diversity of alcoholic fermentation." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/387309.
Full textLa fermentación alcohólica es llevada a cabo por una comunidad microbiana compleja, donde las levaduras del vino juegan un papel importante. En los últimos años, ha habido un creciente interés para mejorar la complejidad del vino en fermentaciones controladas utilizando no sólo S. cerevisiae sino también algunas cepas seleccionadas de levaduras no-Saccharomyces. La investigación sobre la viabilidad de las levaduras y las interacciones tienen un papel fundamental para entender la diversidad de levaduras en fermentaciones mixtas. En esta tesis, se aplicaron técnicas independientes de cultivo para el análisis de muestras de vinos directa incluyendo la secuenciación masiva, fluorescencia por hibridación in situ (FISH) en combinación con microscopía y citometría de flujo, RT-qPCR y EMA-DGGE. Estas técnicas independientes de cultivo permiten una rápida identificación y / o cuantificación de las distintas levaduras del vino. Estas técnicas han sido utilizadas para el análisis de fermentaciones espontáneas en la región del Priorat, siendo las especies H. uvarum y Starm. bacillaris las dos principales especies de levaduras no-Saccharomyces. H. uvarum o Starm. bacillaris pierden gradualmente su cultivabilidad cuando los mostos se inocularon con S. cerevisiae, pero las levaduras se pudieron cuantificar en estado viable pero no cultivable. La pérdida de cultivabilidad de las especies no Saccharomyces fue inducida principalmente por algunos metabolitos secretados por S. cerevisiae, pero los cambios en otros metabolitos principales también influyen. Esta interacción entre levaduras no Saccharomyces con S. cerevisiae es especie y cepa dependiente.
Alcoholic fermentation is driven by complex microbial community, where wine yeasts play an important role. In recent years, there has been growing interest to enhance wine complexity by controlled fermentations using not only S. cerevisiae but also together with some selected non-Saccharomyces yeast strains. Research on yeast viability and interaction has a fundamental role to understand the diversity of yeast in mixed fermentations. In this thesis, culture-independent techniques were developed and applied for direct wine sample analysis including massive sequencing, fluorescence in situ hybridization (FISH) combined with microscopy and flow cytometry, RT-qPCR and EMA-DGGE. These culture-independent techniques enable fast identification and/or quantification of different wine yeasts. These techniques have been used during spontaneous fermentation in Priorat region, and H. uvarum and Starm. bacillaris where the two main non-Saccharomyces yeast species detected. H. uvarum or Starm. bacillaris gradually lost their culturability when musts were inoculated with S. cerevisiae, but quantifiable yeast cells existed in viable but non-culturable state. The culturability loss of non-Saccharomyces was mainly induced by some metabolites secreted from S. cerevisiae, but changes in other main metabolites also had some effect. This interaction of non-Saccharomyces yeast with S. cerevisiae showed the specificity of species and strains.
Friedline, Christopher J. "Phylometagenomics: a new framework for uncovering microbial community diversity." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/499.
Full textRandima, Livhuwani Priscilla. "Rhizosphere microbial diversity in PAH's contaminated and uncontaminated soil." Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11302009-195201/.
Full textLutz, Stefanie. "The microbial diversity and function of Arctic supraglacial biomes." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11871/.
Full textTangherlini, Michael. "Microbial diversity and gene flow in deep-sea sediments." Doctoral thesis, Università Politecnica delle Marche, 2014. http://hdl.handle.net/11566/242906.
Full textMetagenomics has allowed the study of the diversity of organisms which can’t be cultivated and their role in various ecosystems, including soils and marine sediments, inland waters and the open ocean. The analysis of diversity through metagenomic approaches is based on the extraction of genomic DNA, assuming that it is completely associated with living biomass. However, recent studies have shown that the whole metagenome of each environmental sample is composed of different pools, including that of viruses, that associated with microbial biomass and that associated with non-living biomass (i.e, extracellular DNA). The procedures commonly used to isolate DNA from environmental samples do not discriminate between the various pools of DNA, thus affecting the results of investigations carried out. Viromes are metagenomes containing viral DNA. Viruses are not only the most abundant biological entities in the World’s oceans, but through their infection they control both prokaryotic abundance and diversity and important biogeochemical cycles of the marine ecosystem. The metagenomic approach applied to the viral component of marine systems has led to the discovery that viruses can be important agents of gene transfer: in fact, through recombination and integration viruses can either excide portions of the genomes of their hosts and transfer them to other hosts. Despite their importance, viral diversity in the deep-sea benthic ecosystems is still completely unknown and metagenomics seems to be the most effective approach to analyze it. So far, several bioinformatics tools were used to analyze viral sequences in environmental samples, but most of these tools have not been specifically designed for the analysis of viral sequences and comparisons to test for their validity do not exist or are too limited. In this study, we developed a specific procedure for the selective recovery of viral DNA from deepsea sediments. Viral DNA was sequenced, through pyrosequencing techniques, and analyzed comparing three annotation pipelines for metagenomic sequences (MG-RAST, VMGAP, MetaVir). To test their efficiency in the analysis of viral diversity we used both the sequencing data derived from viral metagenomes and those obtained in silico from sequences deposited in public databases. These analyses indicate that the taxonomic and functional diversity of viruses varies depending on the pipeline used. MetaVir proved to be the most reliable pipeline for the annotation of viral taxonomic diversity. However, since this pipeline was not designed for functional annotations of viral sequences, its results must necessarily be integrated with those obtained by other pipelines such as VMGAP. Therefore, this study highlights the need to develop a comprehensive bioinformatics platform for efficient functional and taxonomic annotation of viromes to shed light on the enormous genetic diversity contained in the viruses present in the largest ecosystem on Earth. The viral taxonomic diversity has been explored in marine sediment samples collected in different ocean areas of the globe, ranging from 2000 to 10000 m depth. The results of this analysis have revealed, for the first time, that viral diversity in benthic deep-sea ecosystems, is not only very high but also that some viral families are widespread, despite the environmental and ecological differences in the ecosystems analyzed. The similarity between the samples analyzed in this study and the majority of viromes published to date suggests that several factors contribute to shape the diversity of the viral assemblage. In addition, all viromes have a high functional diversity and also contain putative functions derived from their hosts, including key metabolic functions. The microbial metagenomes are made of DNA associated with living biomass and in deep-sea sediments they are mainly represented by prokaryotes (Bacteria and Archaea). The possibility of studying the microbial communities through metagenomic approaches has allowed us to better understand their role in the marine environment in deep marine environments, which are very difficult to reach, enabling the discovery of new enzymes and metabolic pathways, often useful for industrial or biotechnological applications. The extracellular DNA plays a key role in marine ecosystems, both as a source of nutrients and as a source of genes. It can be released from prokaryotic community during growth and through cell lysis (due to viral infection or to natural cell death). Sediments and soils can also preserve this released DNA, which can be adsorbed onto mineral and organic particles. This preserved extracellular pool can be incorporated into naturally-competent cells, which may undergo natural transformation processes. In this study, the contextual analysis of extracellular and microbial metagenomes in different benthic deep-sea ecosystems, has not only provided information on the specific composition of each pool, but also has revealed that the extracellular DNA contains a high genetic diversity, which to date has never been considered. This genetic diversity represents a major fraction of the genetic diversity associated with the whole metagenome. Most of the genetic diversity of the total DNA is represented by genes related to the extracellular DNA and, on average, about 50 % of the "species" contained in the extracellular DNA is shared with the microbiome. Moreover, the comparison among all the metagenomes showed that viral sequences are present not only in viromes, as expected, but also in microbiomes and extracellular metagenomes. The comparative bioinformatic analysis between all metagenomes has revealed the presence of putative functions involved in different processes of horizontal gene transfer. Of particular relevance are the functions for DNA uptake and mobilization and those related to mobile genetic elements, such as gene transfer agents (GTAs) and prophages. Laboratory experiments conducted in deep-sea sediments also show that the extracellular DNA may be an important genetic resource for the microbial community, since up to 6% of prokaryotic cells appear to be competent and able to acquire new functions. Taken together, these results suggest that deep benthic ecosystems have a high potential for gene transfer that can occur through multiple mechanisms.
Araújo, Solange Pires de. "Produção de inóculo microbiano, obtido de macrófitas aquáticas na Amazônia, com potencial de degradação de hidrocarbonetos de petróleo." Universidade Federal do Amazonas, 2014. http://tede.ufam.edu.br/handle/tede/4307.
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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
The Amazon, which owns the largest fauna and flora in the world presents unparalleled wealth of biological diversity, however, keep intact this megadiversity requires scientific and technological knowledge. In this context, there is an important biotechnological tool that is the bioremediation of impacted environments with petroleum hydrocarbons and derivatives. In the present study samples of microbial communities of fungi and bacteria associated with aquatic macrophytes Eichhornia crassipes (Mart.) Solms, Ichnanthus calvescens Döll and Cyperus ligularis L., were researched. These host plants common at Rio Negro were collected in contaminated environments by oil and oil products at Waterway Station from Manaus. From the species selected, 155 bacterial strains were isolated, being 97 epiphytic and 58 endophytic, and 54 fungi strains, being 30 epiphytic and 24 endophytic. Selective media were used for isolation of microorganisms such as BH liquid medium (Bushhnell Haas) plus oil. The oil and diesel used are from the Base Oil Urucu, Amazonas. The biodegradability tests were performed on selective medium (BH), with the addition of oil as the carbon source known as Medium I This test was repeated with the addition to the medium I the redox indicator 2,6-dichlorophenol indophenol (DCPIP), called medium II. After the evaluationof microbial isolates were selected 6 bacteria and 7 fungi. Molecular identification of bacteria was performed by the 16S ribosomal DNA region and revealed the presence of Bacillus pumilus (endophytic / epiphytic), Lysinibacillus fusiform (epiphytic), Pseudomonas aeruginosa (epiphytic) and Acinetobacter junii (epiphytic/epiphytic). For molecular identification of fungi was performed by the ITS1 and ITS2 region and revealed the presence of Curvularia trifolii (epiphytic), Curvularia clavata (endophytic / epiphytic), Gibberella intermedia (epiphytic/endophytic), Phoma herbarum (epiphytic) and Dothideomycetes sp (epiphytic). These microorganisms were selected for composition of microbial consortium that were used for hydrocarbon biodegradation tests. The measurement of biodegradation of oil and diesel activities was estimated by chromatography and mass spectrometry. In tests we used water of Rio Negro with the aim of approaching research the environment that are being studied. Degradation of hydrocarbons by consortia of fungi and bacteria had significant average values (98.7 to 100%), but did not show any statistical difference between the degradation of the control containing water of the Rio Negro (97.3%). In the experiment with the mixed consortium (FB), there were significant differences, because although the control containing water of the Rio Negro has promoted degradation of diesel by wild microbiota (81.7%), this degradation was lower and statistically different from the mixed consortium (97,5%). Analysis were carried out for degradation of the compounds naphthalene and phenanthrene of diesel by consortia . It was observed that phenanthrene was the best that has been degraded by the mixed consortium (F / B), however the naphthalene was better degraded by the control containing only water from the Rio Negro, highlighting the potential of wild microorganisms that deserve attention in future research, the isolation of these ones in waters from Rio Negro. In the experimental design with the consortia, the results showed that mixed consortia (FB) have potential for use in future bioremediation.
A Amazônia, detentora da maior fauna e flora do mundo apresenta riqueza inigualável de diversidade biológica, entretanto, manter intacta essa megadiversidade requer conhecimentos científicos e tecnológicos. Nesse contexto, situa-se uma importante ferramenta biotecnológica que é a biorremediação de ambientes impactados por hidrocarbonetos de petróleo e derivados. No presente trabalho realizou-se estudo de amostras das comunidades microbianas de fungos e bactérias associadas às macrófitas aquáticas Eichornia crassipes (Mart.) Solms, Ichnanthus calvescens Döll e Cyperus ligularis L. Essas plantas hospedeiras comuns nas águas do rio Negro foram coletadas em ambientes contaminados por petróleo e derivados na Estação Hidroviária de Manaus. Das espécies vegetais selecionadas foram isoladas 155 linhagens de bactérias, sendo 97 epifíticas e 58 endofíticas e 54 cepas de fungos, sendo 30 epifíticos e 24 endofíticos. Foram empregados meio seletivo para isolamento dos microrganismos tal como meio liquido BH (Bushhnell Haas) acrescido de petróleo. O petróleo e o diesel utilizados foram provenientes da Base Petrolífera de Urucu, Amazonas. Os ensaios de biodegradabilidade foram realizados em meio seletivo (BH), com a adição de petróleo como fonte de carbono denominado Meio I. Este ensaio foi repetido com a adição ao meio I do indicador redox 2,6-diclorofenol indofenol (DCPIP), denominado meio II. Após a avaliação dos isolados microbianos foram selecionados 6 bactérias e 7 fungos. A identificação molecular das bactérias foi realizada por meio da região do DNA ribossomal 16S e revelou a presença de Bacillus pumilus (Endofítica/epifítica), Lysinibacillus fusiformes (Epifítica), Pseudomonas aeruginosa (Epifítica) e Acinetobacter junii (Epifítica/epifítica). A identificação molecular dos fungos foi realizada por meio da região TS1 e ITS2 e revelou a presença das seguintes espécies: Curvularia trifolii (epifítica), Curvularia clavata (endofítica/epifítica), Gibberella intermedia (epifítica/endofitica), Phoma herbarum (epifítica) e Dothideomycetes sp (epifítica). Estes microrganismos foram selecionados para composição do consórcio microbianos que foram utilizados em ensaios de biodegradação de hidrocarbonetos. A mensuração das atividades de biodegradação de petróleo e diesel foi estimada por cromatografia e espectrometria de massa. Nos ensaios utilizou-se água do rio Negro com o objetivo de aproximar a pesquisa ao ambiente de estudo. A degradação dos hidrocarbonetos pelos consócios de fungos e bactérias apresentaram médias significativas (98,7-100%), mas não apresentaram diferenças estatísticas entre a degradação do controle contendo água do rio Negro (97,3%). No experimento com o consórcio misto (F/B), houve diferenças significativas, pois embora o controle contendo água do rio Negro tenha promovido degradação do diesel pela microbiota selvagem (81,7%), esta degradação foi inferior e diferente estatisticamente do consórcio misto (97,5%). Foram realizadas análises de degradação dos compostos naftaleno e fenantreno do óleo diesel pelos consórcios Observou-se que o composto fenantreno foi o que melhor foi degradado pelo consórcio misto (F/B). Entretanto, o naftaleno foi melhor degradado pelo controle contendo somente água do rio Negro, destacando o potencial dos microrganismos selvagens que merecem atenção nas futuras pesquisas, no isolamento destes em águas do rio Negro. O índice de toxicidade dos extratos microbianos foram avaliados como toxicidade moderada para o consórcio misto (F/B), já para o consórcio de fungos e consórcios de bactérias não apresentou toxicidade. No planejamento experimental com os consórcios, os resultados obtidos demonstraram que consórcios mistos (F/B) apresentaramm potencial para uso em futuros processos de biorremediação.
Howarth, Richard. "Diversity and function of morphologically conspicuous sulfide-oxidising bacteria." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287821.
Full textCarder, Phyllis. "Microbial Communities of Spinach at Various Stages of Plant Growth From Seed to Maturity." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/34104.
Full textLittle is known about how the leaf bacterial community is affected by the seed microbiota at different stages of plant development. The bacterial populations of spinach seed and leaves after germination were compared using DGGE, to assess bacterial community richness, and real-time PCR to compare the abundance of select phyla (total bacteria, Actinobacteria, Bacteroidetes, Firmicutes, α-Proteobacteria and β- Proteobacteria). To determine the effect of environment, the plants were grown in the field and growth chambers. Vertical transmission of bacterial community members was evident; the developmental stage of the plant affected the richness and abundance of select bacterial phyla. The bacterial richness of plants grown in the two environments was not affected. However, overall numbers of bacteria increased in field grown samples in comparison to those produced in growth chambers during development. A statistically significant interaction was seen between growth stage and environment with each of the selected phyla. Populations on cotyledons were smaller than mature leaves, but were not significantly different than the 3-4 leaf stage plants. The culturable populations of bacteria on seeds (~5 log CFU/g) were significantly smaller than determined using real time PCR (~7 log copies). Of these bacteria cultured from spinach seeds, isolates belonging to the genera Pantoea were found to inhibit growth of E. coli O157:H7 in vitro. This study highlights the importance of vertical transmission on the bacterial community of plants and suggests the importance of developing strategies to influence these communities on seed to control human and plant pathogens on the leaf surface.
Master of Science in Life Sciences
Thapa, Namrata. "Studies on Microbial Diversity Associated with some fish products of the Eastern Himalayas." Thesis, University of North Bengal, 2002. http://hdl.handle.net/123456789/1340.
Full textHuber, Julie A. "Phylogenetic and physiological diversity of subseafloor microbial communities at deep-sea seamounts /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10991.
Full textGarrido, Molina Laura. "Molecular characterization of microbial diversity in wastewater treatment and reuse." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/96237.
Full textWastewater generation is an inevitable consequence of human activities. These activities modify the characteristics of the original waters, contaminating them and invalidating subsequent application for other uses. Dumping of raw sewage causes damage, sometimes irreversible, to the environment. On the other hand, the discharge of untreated sewage poses risks to public health. Thus, wastewater treatment becomes an important need in our society. Wastewater treatment plants constitute one of the most important biotechnological processes used worldwide to treat municipal and industrial sewage. From a biological point of view, microorganisms play an important role in wastewater treatment since they are the main responsible of the remove of organic matter and nutrients from this sewage. Furthermore, water reuse is becoming increasingly important as a component of sustainable management of water resources. In this thesis we investigated the composition of microbial communities in different environments related to wastewater treatment and reuse. First, we studied and compared the microbial communities found in conventional processes with two atypical treatment systems (activated sludge from a seawater-processing EDAR and constructed wetlands). On the other hand, we determined how different was the microbial profile of a treated wastewater versus a natural freshwater, and tried to find out an alternative indicator of water quality. Finally, we examined the microbial population associated with the problems arising from water reuse. Samples of a marine activated sludge were analyzed by using the full-cycle rRNA approach (denaturing gradient gel electrophoresis, clone libraries and in situ hybridization), obtaining a picture of the composition of the community completely different from a conventional activated sludge, with particularly a low presence of Betaproteobacteria. In addition, detection of the functional gene amoA corroborated the presence of ammonia oxidizers, corresponding probably to different genera from those described in the literature. On the other hand, the microbial communities found in experimental constructed wetlands belonged to species related with organic matter removal. The study of the profiles of these microbial communities allowed determining the effect of the type of plant, hydraulic design and organic matter load of these systems in their composition. Comparing our atypical treatment systems with conventional ones, we can conclude that each system has its specific microbial community, adapted to its environmental conditions, with the same functions being carried out by different groups. Besides, examination of microbial diversity profiles of treated wastewater from different EDARs and comparison with natural non-contaminated water showed that sewage effluents have a common fingerprint, which differs from natural water. Thus, taking into account the most abundant groups found in these types of waters, we proposed the use of the Bacteroidetes, Gammaproteobacteria and Nitrospira / Betaproteobacteria ratio as an alternative indicator of ecological water quality. Concerning water reuse, we focused on an example of a biofouling problem derived from the use of reclaimed water in a drip irrigation system. In these biofilms the microbial community was mainly composed of thermophilic and sporulated microorganisms, suggesting that high temperatures within the irrigation infrastructure selected these populations. Thus, it seemed that the conditions in the system may be more important than the composition of reclaimed water itself.
Mackenzie, Calderón Roy. "Ecology of hot spring microbial mats: Diversity, microheterogeneity, and biogeography." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/286283.
Full textThe results presented in this PhD thesis include a description on the thermophilic populations thriving in biodiversity hot spots such as the Valdivian Rain Forest in Patagonia, and Cloud Forests in Costa Rica, as well as the Atacama Desert and Deception Island in the South Shetland Archipelago in Antarctica. The bacterial community structure of several hot spring microbial mats was characterized by means of molecular microbial ecology methods, and the relationship between diversity and temperature was measured at different spatial scales. Phylum Cyanobacteria was identified as the major component of the microbial community by at least three different sequencing methods with different taxonomic resolution, and a deeper diversity analysis on this group showed no substantial differences between samples taken in winter and summer, although significant similarities were observed among hot springs with common surrounding environments. The horizontal microheterogeneity of microbial mats at a centímeter scale also revealed Chloroflexi as dominant phylum together with Cyanobacteria, and a temperature differentiation was observed between both potential primary producers. Significant diversity shifts were detected among closely situates samples in single mats, but at the same time, samples within mat patches showed a high community structure similarity. A deeper characterization of the bacterial community structure revealed the presence of several heterotrophic groups such as Cytophagia and Sphingobacteria; Thermales; and Alpha, Beta, and Gammaproteobacteria; among others. When compared with other thermophilic microbial mats along a latitudinal gradient, no relationship was detected between richness and latitude, as samples closer to the equator were not more diverse or harbored more richness than samples closer to the pole. Temperature, on the other hand, influenced significantly the bacterial richness. Finally, samples at local, regional and global scales (up to 1000 m2) showed a decrease in similitude as geographic distance, but not at the continental scale.
Kaambo, Eveline. "Investigation of South African estuarine microbial species and genome diversity." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8171_1186398717.
Full textA study of the microbial diversity in sediments of the Great Berg River estuary is carried out using modern molecular phylogenetic methods. The aim of this study was to determine the effect of (pollution by) the effluents of the fish industry on the composition of the microbial community in the sediments. The diversity in microbial groups of sediment samples that received wastewater from the local fishing industry was investigated by a PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) approach and compared to an unaffected site.
Martijn, Joran. "Exploration of microbial diversity and evolution through cultivation independent phylogenomics." Doctoral thesis, Uppsala universitet, Molekylär evolution, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327310.
Full textShi, Shengjing. "Influence of root exudates on soil microbial diversity and activity." Lincoln University, 2009. http://hdl.handle.net/10182/1549.
Full textBamforth, Selina Mary. "Microbial diversity and biogeochemical activity in a riparian buffer zone." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437587.
Full textKlepac-Ceraj, Vanja 1976. "Diversity and phylogenetic structure of two complex marine microbial communities." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28641.
Full textIncludes bibliographical references (p. 102-103).
(cont.) competitive mechanisms are too weak to purge diversity from within them.
Molecular surveys have revealed that microbial communities are extraordinarily diverse. Yet, two important questions remain unanswered: how many bacterial types co-exist, and do such types form phylogenetically discrete units of potential ecological relevance? This thesis explores these questions by investigating bacterial diversity in two complex marine communities (coastal bacterioplankton and sediment sulfate-reducing bacteria) by (i) comprehensive analysis of large 16S rRNA clone libraries, and (ii) refinement and application of parametric diversity estimators. Identification and correction of sequence artifacts demonstrated their potentially significant contribution to diversity estimates. Still, hundreds of unique rRNA sequences (ribotypes) were detected in the corrected libraries, and extrapolation to community diversity with commonly used non-parametric diversity estimators suggested at least thousands of co-existing ribotypes in the two communities. However, close inspection revealed that the non-parametric estimators likely lead to underestimation of ribotype diversity in the clone libraries. Thus, an improved parametric method was developed and shown to closely fit the data. The extrapolated total ribotype diversity in the sample by the improved method was up to one order of magnitude higher than estimated with common non-parametric approaches. Most significantly, the compensation for artifacts and improved estimation revealed that the vast majority of ribotypes fall into microdiverse clusters containing <1% sequence divergence. It is proposed that the observed microdiverse clusters form important units of differentiation in microbial communities. They are hypothesized to arise by selective sweeps and contain high diversity because
by Vanja Klepac-Ceraj.
Ph.D.
Feinstein, Larry M. "Microbial Functional Activity and Diversity Patterns at Multiple Spatial Scales." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1341967745.
Full textPorter, Ashleigh Fay. "Next generation sequencing to explore microbial diversity, origins and evolution." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/24919.
Full textMilanovic, Vesna, and Vesna Milanovic. "Study of microbial diversity and yeast interactions using molecular methods." Doctoral thesis, Università Politecnica delle Marche, 2012. http://hdl.handle.net/11566/242115.
Full textMicroorganisms play a central role in the regulation of ecosystem processes, and they comprise the vast majority of species on Earth. The aim of this PhD thesis was to improve our knowledge on microbial diversity and dynamics of microbial communities in various conditions and ecological habitats related to environmental and industrial biotechnological processes as well as on the microbial interactions by using molecular and classic methods. In the first part of the present thesis it was evaluated the efficiency of the Mediterranean biomixture (the main part of a biobed) in the degradation of fungicides generally used to control pests in vineyards and to assess their effects on microbial community. Biobeds are biological systems developed all over EU countries to protect water-bodies from pesticide contamination at farm level. Results showed that the biomixture had a good capability of degrading pesticides. Indeed, at the end of the experiment (112 days), the concentration of most of the pesticides was close to complete degradation. Denaturing gradient gel electrophoresis (DGGE) analysis showed an evident modification of microbial diversity after the addition of fungicides. However, at the end of degradation process, no significant changes in the composition of microbial community were seen. In the specific substrate used in the biomixture, both yeast flora and ascomycete filamentous fungi seemed to be involved in the degradation activity. In the second part of this PhD thesis it was investigated on the possible use of crude glycerol as a soil amendment. Crude glycerol is a principal by-product of biodiesel production. As the biodiesel industry is rapidly expanding over the last years, a glut of crude glycerol is being created, so there is an urgent need to find alternative uses for this by-product. Considering that crude glycerol is rich in organic compounds, a laboratory experiment was carried out to study the effect of different glycerol amounts on microbial diversity and chemical and biochemical properties of agricultural soil in order to assess the possible agronomical use of crude glycerol without further purification. Results of culture dependent methods showed that the addition of crude glycerol has stimulated the growth of cultivable bacteria and fungi, while DGGE analysis demonstrated that the added glycerol increase bacterial diversity in the soil. Microbial activity in all treated soils reached a steady-state condition in terms of daily respiration activity indicating a positive adaptation of the microbial biomass. This initial investigation showed that the crude glycerol does not seem to have negative effects on the soil but rather causes the development of microbial communities and increases microbial diversity. In the third part of this thesis, the yeast communities colonising grape berry surfaces were evaluated for the influence of fungicide treatments in an organic vineyard (copper/sulphur-based products) and a conventional vineyard (commonly used fungicides). Analysis of yeast abundance and diversity was carried out on grape berries and the grape juice during fermentation, using culture-dependent and -independent approaches. Yeast abundance was as generally reported for mature grapes, with higher counts from grapes treated with conventional fungicides. Direct isolation and DGGE analysis of initial grape samples showed less yeast species diversity in the organic vineyard compared with the conventional vineyard. In the organic and conventional vineyards, the dominant yeasts were Candida zemplinina and Hanseniaspora uvarum, respectively, typical species that colonise surfaces of mature grape berries. Saccharomyces cerevisiae was isolated by traditional methods and detected by DGGE only at the end of fermentation, with lower levels in the organic samples. Moreover, S. cerevisiae showed less intraspecific diversity in the organic samples (two genotypes), in comparison with the conventional samples (six genotypes). Altogether, these results show that the copper and sulphur treatments have greater negative influences on abundance and diversity of grape berry yeast communities (included S. cerevisiae), in comparison with fungicides used for conventional treatments. In the fourth part of the thesis, the attention was focused on the yeast interactions during wine fermentation. The use of a multistarter fermentation process with S. cerevisiae and non Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. The aim of this work was to study the influence of Starmerella bombicola on S. cerevisiae gene expression and enzymatic activity of pyruvate decarboxylase (Pdc1) and alcohol dehydrogenase (Adh1), the two key enzymes of the alcoholic fermentation pathway. The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation byproducts. Also the alcoholic fermentation of S. cerevisiae was influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation which was more evident in mixed culture. S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola was not limited to a simple additive contribution but its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene expression and enzymatic activity of alcohol deydrogenase and pyruvate decarboxylase.
Sousa, Paula Sanchez de [UNESP]. "Isolamento e caracterização de leveduras de Polybia ignobilis (Hymenoptera: Vespidae)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94983.
Full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Polybia ignobilis é uma vespa social que apresenta uma alimentação variável e inespecífica, consumindo outros insetos, pedaços de animais mortos, néctar, polpa de madeira e água. Dentro do ninho ocorre a trofalaxia, onde o alimento é distribuído entre os indivíduos da colônia através de secreção labial, podendo ocorrer entre adulto e larva ou apenas entre adultos, propiciando a dispersão de micro-organismos. A associação entre leveduras e insetos pode ser considerada transitória, onde os insetos podem atuar como vetores na dispersão desses micro-organismos sem benefício nutricional; por outro lado, também pode ser considerada como uma associação benéfica, onde o inseto utiliza as leveduras como complemento alimentar. O presente estudo teve como objetivos: caracterizar a comunidade de leveduras associadas à P. ignobilis; verificar se há relação entre a distribuição das leveduras nas diferentes castas da vespa e contribuir com a formação de um banco temático de leveduras isoladas de insetos sociais. Indivíduos do ninho de P. ignobilis e amostras de mel foram coletados no campus da UNESP - Rio Claro. O isolamento e identificação das estirpes foi feita de acordo com a metodologia clássica descrita em YARROW (1998). Foram isoladas 167 estirpes, sendo 59 do primeiro ninho e 108 do segundo. Após uma seleção baseada em análises morfológicas, bioquímicas e perfil de bandas de microsatélites (MSP-PCR) estirpes representativas de cada grupo, bem como as estirpes únicas foram identificadas pelo sequênciamento da região D1/D2 do rDNA 26S. Os resultados revelaram a prevalência no primeiro ninho dos gêneros Candida, Cryptococcus, Hanseniaspora e Rhodotorula, compreendendo 45% do total das estirpes, sendo as espécies mais freqüentes Candida azyma, Candida chrysomelidarum, Cryptococcus liquefaciens e Rhodotorula mucilaginosa. No segundo ninho, as espécies...
Polybia ignobilis is a social wasp that features a variable and unspecific alimentation, eats other insects, bits of dead animals, nectar, wood pulp and water. Inside the nest occurs trofalaxis, where food is distributed among individuals of the colony through labial secretion, it can occur between adult and larva or adults only, being vectors in the dispersion of microorganisms. The association between yeasts and insects can be considered temporary, where the insects serve as vectors in the dispersal of these micro-organisms without nutritional benefit; on the other hand, can also be regarded as a beneficial association, where the insect uses the yeasts as a food supplement. This present study aimed to characterize the yeast community associated with P. ignobilis; verify whether exists a relation between the distribution of yeasts in different varieties of wasp and contribute to the formation of a thematic database of yeasts isolated from social insects. Individuals from the nest of P. ignobilis and honey samples were collected on the campus of UNESP - Rio Claro. The isolation and identification of strains was made according to classical methodology described in YARROW (1998). We isolated 167 strains, 59 and 108 of the first and second nest. After a selection based on morphological, biochemical and microsatellite band profiles (MSP-PCR) representative strains of each group as well as unique strains were identified by sequencing the D1/D2 region of 26S rDNA. The results revealed the prevalence in the first nest of Candida, Cryptococcus, Hanseniaspora and Rhodotorula, comprising 45% of all strains, being the most frequent species Candida azyma, Candida chrysomelidarum, Cryptococcus liquefaciens and Rhodotorula mucilaginosa. In the second nest of the species that prevailed were Aureobasidium pullulans, Meyerozyma guillermondii. Some strains may constitute new... (Complete abstract click electronic access below)
Lopez-Velasco, Gabriela. "Molecular Characterization of Spinach (Spinacia Oleracea) Microbial Community Structure and its Interaction With Escherichia coli O157:H7 in Modified Atmosphere Conditions." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37601.
Full textPh. D.
Suen, Garret. "Understanding prokaryotic diversity in the post-genomics era." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available, full text:, 2008. http://wwwlib.umi.com/cr/syr/main.
Full textSmith, Jacques J. "Microbial diversity and gene mining in Antarctic Dry Valley mineral soils." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5762_1183463992.
Full textSoil communities are regarded as among the most complex and diverse assemblages of microorganisms with estimated bacterial numbers in the order of 10â?¹ cells.gâ?»¹
. Studies on extreme soils however, have reported lower cell densities, supporting the perception that the so-called extreme environments exhibit low species diversity. To assess the extent of microbial diversity within an extreme environment, the mineral soils of the Dry Valleys, Ross Dependency, Eastern Antarctica were investigated using 16S rDNA analysis.
Karlinska-Batres, Klementyna [Verfasser], and Gert [Akademischer Betreuer] Wörheide. "Microbial diversity of coralline sponges / Klementyna Karlinska-Batres. Betreuer: Gert Wörheide." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1067401628/34.
Full textVidal, Dura Andrea. "Controls on microbial diversity and sediment biogeochemistry along a dynamic estuary." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/18218/.
Full textPino, Vanessa. "Soil Microbial Diversity Across Different Agroecological Zones in New South Wales." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16705.
Full textFergusson, Stacey Victoria. "Microbial diversity in the human mouth : dominant genera and their interactions." Thesis, University of York, 2010. http://etheses.whiterose.ac.uk/1472/.
Full textMarkland, Kendra Marie. "Relating functional microbial diversity to eastern Iowa alluvial aquifer groundwater chemistry." Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6197.
Full textBottos, Eric. "Biodiversity and activity of microbial mat communities from Canadian high Arctic ice shelf ecosystems." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100776.
Full textSingh, Prashant. "Microbial assemblage in grapevine's phyllosphere : who is the driver ?" Thesis, Montpellier, SupAgro, 2018. http://www.theses.fr/2018NSAM0042/document.
Full textVitis vinifera subsp. vinifera L., the main grape species are grown for fruit and wine production over the world is a natural host of a wide variety of prokaryotic and eukaryotic microorganisms that interact with grapevine, having either beneficial or phytopathogenic effects. They could also play a major role in fruit yield, grape quality, plant protection and, ultimately, in the pattern of grape fermentation and wine production. Phyllosphere (consists of the aerial parts of the plant) is one of the most prevalent microbial habitats on earth and is quite a neglected milieu, especially in grapevines and many questions related to this microbial habitat, are still unanswered.This thesis is an effort to answer a very fundamental question in microbial ecology- what are the drivers that shape the microbiome in the grapevine's phyllosphere? The phyllosphere microbial communities (PMCs) live at the plant-climate interface and its ability to establish, thrive and reproduce on the leaf or fruit surface depends on several microbial functional traits, such as the ability to attach to the cuticle and to use the foliar nutrients as well as well as to the prevailing climatic conditions like temperature, air humidity and rain. Leaf or fruit chemistry, physiology, and morphological structure differ among plant genotype and species as all these traits have a genetic basis, and this variation may lead to a different combination of PMCs assemblage among plant genotypes. Hence, the first objective of our work was to assess the impacts of grapevine cultivars (varieties of Vitis vinifera L) and grapevine species (entirely different Vitis species) on microbiome assemblage in the phyllosphere at a particular geographic location (to minimize the environmental effects). Later on, impacts of some commercially important grapevine cultivars and terroirs (represented by three French climate zones) were also assessed and compared. Impacts of the season and exterior plant organs (leaf and berries) on microbial taxa structuring in the phyllosphere was also assessed and presented in this work. Furthermore, species-specific impacts on phyllosphere microbiome were also tested and represented.Overall our study assessed and compared the many facets of the factors that may influence themicrobiome structure in the phyllosphere with a special focus on relative selection pressure exerted by grapevine genotype and its interaction with different climatic conditions (or terroir), which may improve our chances to find genes that controls PMCs on phyllosphere, and simultaneously increase our confidence that those genes are actually important in realistic environments and probably those genes would give us new insights for breeding new and healthy grape varieties displaying better traits on their phyllosphere. Moreover, considering that the plant PMCs plays a crucial role in plant health and fitness as it can modulate leaf susceptibility to infection, this study could also be helpful to develop innovative and natural biocontrol methods or phytostimulation against grapevine pathogens or rethink breeding schemes for the creation of innovative resistant varieties