Global ETD Search

1	Gene Discovery in Antarctic Dry Valley Soils. Anderson, Dominique Elizabeth. January 2008 (has links) <p>The metagenomic approach to gene discovery circumvents conventional gene and gene product acquisition by exploiting the uncultured majority of microorganisms in the environment. It was demonstrated in this study that metagenomic methods are suitable for gene mining in extreme environments that harbor very high levels of unculturable microorganisms. DNA was extracted from Antarctic mineral soil samples taken from the Miers Valley, Antarctica. The metagenomic DNA was also used to construct a fosmid library comprising over 7900 clones with an average insert size of 29 kb. PCR amplification using bacterial and archaeal 16S rRNA gene specific primers and subsequent denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rDNA amplicons showed that a small percentage of bacterial diversity (&gt / 1%) was captured in the metagenomic fosmid library. Activity-based screening for lipase and esterase genes using a tributyrin plate assay yielded twelve positive clones. LD1, a putative, novel cold-active GDSL lipase/esterase was identified and sequenced. The C-terminal domain of the ORF was found to be an autotransporter similar to those associated with type V secretion systems in Gram negative bacteria. Sub-cloning of the gene resulted in lipolytic activity in E. coli. Preliminary enzyme assays have determined that LD1 hydrolyses p-nitrophenyl esters with chain lengths shorter than C10, an indication that the enzyme is an esterase. Complete purification and characterisation of this enzyme is subject to further study.</p> Metagenomic DNA Fosmid library Functional screening lipase Esterase PCR DGGE Diversity.
2	Characterisation of a DNA ligase from an Antarctic metagenomic library Booyse, Dean January 2011 (has links) <p>A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E. coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations.</p>
3	Gene Discovery in Antarctic Dry Valley Soils. Anderson, Dominique Elizabeth. January 2008 (has links) <p>The metagenomic approach to gene discovery circumvents conventional gene and gene product acquisition by exploiting the uncultured majority of microorganisms in the environment. It was demonstrated in this study that metagenomic methods are suitable for gene mining in extreme environments that harbor very high levels of unculturable microorganisms. DNA was extracted from Antarctic mineral soil samples taken from the Miers Valley, Antarctica. The metagenomic DNA was also used to construct a fosmid library comprising over 7900 clones with an average insert size of 29 kb. PCR amplification using bacterial and archaeal 16S rRNA gene specific primers and subsequent denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rDNA amplicons showed that a small percentage of bacterial diversity (&gt / 1%) was captured in the metagenomic fosmid library. Activity-based screening for lipase and esterase genes using a tributyrin plate assay yielded twelve positive clones. LD1, a putative, novel cold-active GDSL lipase/esterase was identified and sequenced. The C-terminal domain of the ORF was found to be an autotransporter similar to those associated with type V secretion systems in Gram negative bacteria. Sub-cloning of the gene resulted in lipolytic activity in E. coli. Preliminary enzyme assays have determined that LD1 hydrolyses p-nitrophenyl esters with chain lengths shorter than C10, an indication that the enzyme is an esterase. Complete purification and characterisation of this enzyme is subject to further study.</p> Metagenomic DNA Fosmid library Functional screening lipase Esterase PCR DGGE Diversity.
4	Characterisation of a DNA ligase from an Antarctic metagenomic library Booyse, Dean January 2011 (has links) <p>A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E. coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations.</p>
5	Characterisation of a DNA ligase from an Antarctic metagenomic library Booyse, Dean January 2011 (has links) A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E. coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations. / Magister Scientiae - MSc Metagenomic DNA Sequence based screening NAD+-dependent DNA ligase Ligase Antarctica Bioinformatics
6	Characterisation of a DNA ligase from an Antarctic metagenomic library Booysen, Dean January 2011 (has links) A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E.coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations. / Magister Scientiae - MSc Metagenomic DNA Sequence based screening NAD+-dependent DNA ligase Ligase Antarctica Bioinformatics
7	Gene Discovery in Antarctic Dry Valley Soils Anderson, Dominique Elizabeth January 2008 (has links) Magister Scientiae - MSc / The metagenomic approach to gene discovery circumvents conventional gene and gene product acquisition by exploiting the uncultured majority of microorganisms in the environment. It was demonstrated in this study that metagenomic methods are suitable for gene mining in extreme environments that harbor very high levels of unculturable microorganisms. DNA was extracted from Antarctic mineral soil samples taken from the Miers Valley, Antarctica. The metagenomic DNA was also used to construct a fosmid library comprising over 7900 clones with an average insert size of 29 kb. PCR amplification using bacterial and archaeal 16S rRNA gene specific primers and subsequent denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rDNA amplicons showed that a small percentage of bacterial diversity was captured in the metagenomic fosmid library. Activity-based screening for lipase and esterase genes using a tributyrin plate assay yielded twelve positive clones. LD1, a putative, novel cold-active GDSL lipase/esterase was identified and sequenced. The C-terminal domain of the ORF was found to be an autotransporter similar to those associated with type V secretion systems in Gram negative bacteria. Sub-cloning of the gene resulted in lipolytic activity in E. coli. Preliminary enzyme assays have determined that LD1 hydrolyses p-nitrophenyl esters with chain lengths shorter than C10, an indication that the enzyme is an esterase. Complete purification and characterisation of this enzyme is subject to further study. / South Africa Metagenomic DNA Fosmid library Functional screening lipase Esterase PCR DGGE Diversity
8	Characterisation of a DNA ligase from an Antarctic metagenomic library Booysen, Dean January 2011 (has links) >Magister Scientiae - MSc / A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E. coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations Metagenomic DNA sequence based screening NAD+-dependent DNA ligase ligase Antarctica bioinformatics
9	Identifizierung und Charakterisierung von Genen und korrespondierenden Genprodukten aus Metagenombanken, die Butanol-Dehydrogenase-Aktivität oder proteolytische Aktivität vermitteln / Identification and characterization of genes and encoding gene products of metagenomic libraries conferring butanol dehydrogenase activity or proteolytic activity Waschkowitz, Tanja 03 May 2006 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science Metagenomik Umweltgenbanken Screening-Strategien Butanol-Dehydrogenasen Proteasen Metagenomic metagenomic DNA libraries screening strategies butanol dehydrogenases proteases 42.30 Mikrobiologie WUV 000 Angewandte Mikrobiologie WUK 000 Genetik der Mikroorganismen Molekularbiologie der Mikrorganismen
10	Charakterisierung und Nutzung der mikrobiellen Diversität extremer Habitate der Kamtschatka-Region / Characterization of the microbial diversity of extreme habitats in the Kamchatka-region Schuldes, Jörg 30 April 2008 (has links) No description available. 500 Naturwissenschaften allgemein Mathematics and Computer Science Metagenomik Umweltgenbanken Screening-Strategien 16SrRNA-Genanalysen Kamtschatka heiße Quellen Esterasen Lipasen Proteasen; Metagenomic metagenomic DNA libraries screening strategies 16SrRNA gene analyses Kamchatka hot springs esterases lipases proteases 42.3 WUV 000 Angewandte Mikrobiologie WUK 000 Genetik der Mikroorganismen

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