Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the... more Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the efficient conversion of biomass into bioethanol, it is essential that sugars from both the cellulose and hemicellulose fractions of lignocellulose be utilised. We describe the development of a recombinant yeast system for the fermentation of cellulose and xylose, the most abundant pentose sugar in the hemicellulose fraction of biomass. The brewer's yeast Saccharomyces pastorianus was chosen as a host as significantly higher recombinant enzyme activities are achieved, when compared to the more commonly used S. cerevisiae. When expressed in S. pastorianus, the Trichoderma reesei xylose oxidoreductase pathway was more efficient at alcohol production from xylose than the xylose isomerase pathway. The alcohol yield was influenced by the concentration of xylose in the medium and was significantly improved by the additional expression of a gene encoding for xylulose kinase. The xylose redu...
Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during ... more Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during oocyte maturation for use after fertilization and are synthesized in the liver or fat body as a common precursor termed vitellogenin. Hybridization with cloned DNA complementary to vitellogenin messenger RNA has revealed a surprisingly high degree of evolutionary conservation of sequence of vitellogenin genes among insects, amphibians and birds. The synthesis of vitellogenin in vertebrates is directly under the control of oestrogen at the level of gene transcription. In the frog, Xenopus, vitellogenin genes occur as a multigene family, four of which are actively expressed and are grouped as A and B genes. This multiplicity offers a useful system for investigating the possible selective hormonal regulation of expression of individual members of multigene families. When X. laevis vitellogenin genes were activated by oestrogen in the liver of whole animals or in cultures of parenchymal cells, the two groups of expressed genes were not induced in an identical manner in cells from male and female animals. The activation of A and B groups of genes was non-coordinate in male hepatocytes and coordinate in female cells. Prior exposure of male hepatocytes to oestradiol in vivo or in culture caused the pattern of expression to shift to that in female cells. Since the X. laevis oocyte itself does not synthesize vitellogenin in response to oestrogen, an attempt was made to activate its dormant vitellogenin genes by transferring oestrogen-binding proteins from the liver. Preliminary results show that the microinjection into the oocyte of a preparation containing liver receptor-hormone complex led to the synthesis of vitellogenin by the oocyte. Extension of these experiments will not only enable a more precise analysis of the activation of the vitellogenin multigene family to be made but will also provide direct functional evidence for the role played by steroid hormone receptors in regulating gene expression.
Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the... more Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the efficient conversion of biomass into bioethanol, it is essential that sugars from both the cellulose and hemicellulose fractions of lignocellulose be utilised. We describe the development of a recombinant yeast system for the fermentation of cellulose and xylose, the most abundant pentose sugar in the hemicellulose fraction of biomass. The brewer's yeast Saccharomyces pastorianus was chosen as a host as significantly higher recombinant enzyme activities are achieved, when compared to the more commonly used S. cerevisiae. When expressed in S. pastorianus, the Trichoderma reesei xylose oxidoreductase pathway was more efficient at alcohol production from xylose than the xylose isomerase pathway. The alcohol yield was influenced by the concentration of xylose in the medium and was significantly improved by the additional expression of a gene encoding for xylulose kinase. The xylose redu...
Lager yeasts, Saccharomyces pastorianus, are interspecies hybrids between S. cerevisiae and S. eu... more Lager yeasts, Saccharomyces pastorianus, are interspecies hybrids between S. cerevisiae and S. eubayanus and are classified into Group I and Group II clades. The genome of the Group II strain, Weihenstephan 34/70, contains eight so-called 'lager-specific' genes that are located in subtelomeric regions. We evaluated the origins of these genes through bioinformatic and PCR analyses of Saccharomyces genomes. We determined that four are of cerevisiae origin while four originate from S. eubayanus. The Group I yeasts contain all four S. eubayanus genes but individual strains contain only a subset of the cerevisiae genes. We identified S. cerevisiae strains that contain all four cerevisiae 'lager-specific' genes, and distinct patterns of loss of these genes in other strains. Analysis of the subtelomeric regions uncovered patterns of loss in different S. cerevisiae strains. We identify two classes of S. cerevisiae strains: ale yeasts (Foster O) and stout yeasts with patterns...
Journal of immune based therapies and vaccines, 2006
The heat shock protein, Hsp70, has been shown to play an important role in tumour immunity. Vacci... more The heat shock protein, Hsp70, has been shown to play an important role in tumour immunity. Vaccination with Hsp70-peptide complexes (Hsp70-PCs), isolated from autologous tumour cells, can induce protective immune responses. We have developed a novel method to identify synthetic mimic peptides of Hsp70-PCs and to test their ability to activate T-cells. Peptides (referred to as "recognisers") that bind to Hsp70-PCs from the human breast carcinoma cell line, MDA-MB-231, were identified by bio-panning a random peptide M13 phage display library. Synthetic recogniser peptides were subsequently used as bait in a reverse bio-panning experiment to identify potential Hsp70-PC mimic peptides. The ability of the recogniser and mimic peptides to prime human lymphocyte responses against tumour cell antigens was tested by stimulating lymphocytes with autologous peptide-loaded monocyte-derived dendritic cells (DCs). Priming and subsequent stimulation with either the recogniser or mimic p...
Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during ... more Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during oocyte maturation for use after fertilization and are synthesized in the liver or fat body as a common precursor termed vitellogenin. Hybridization with cloned DNA complementary to vitellogenin messenger RNA has revealed a surprisingly high degree of evolutionary conservation of sequence of vitellogenin genes among insects, amphibians and birds. The synthesis of vitellogenin in vertebrates is directly under the control of oestrogen at the level of gene transcription. In the frog, Xenopus, vitellogenin genes occur as a multigene family, four of which are actively expressed and are grouped as A and B genes. This multiplicity offers a useful system for investigating the possible selective hormonal regulation of expression of individual members of multigene families. When X. laevis vitellogenin genes were activated by oestrogen in the liver of whole animals or in cultures of parenchymal cell...
The International Journal of Biochemistry & Cell Biology, 2000
Living organisms when subjected to various forms of environmental stress mount a physiological re... more Living organisms when subjected to various forms of environmental stress mount a physiological response to survive the long- and short-term ill-effects of the stress. The stress response may involve selective shut down of non-essential metabolic activities and the repair of macromolecular damage resulting from the stress. Messenger RNA splicing in cultured HeLa cells is one of the processes inhibited by heat stress. Splicing is protected from such inhibition in stress-preconditioned cells that have acquired a tolerant state characterised by increased cell survival and resistance to other environmental stresses. Stress tolerant cells have heat shock proteins (HSPs) that had been induced by the preconditioning process. To examine the biochemical changes induced by stress in the splicing apparatus, we analysed the small nuclear ribonucleoprotein (snRNP) particles associated with spliceosomes in normal, stressed, and stress tolerant cells. We show that (a) the spliceosomal component U4/U5/U6 snRNP particle is disassembled by heat stress into intermediates of splicing assembly, (b) prior induction of stress tolerance protects the structural and functional integrity of snRNPs if cells are subsequently exposed to a severe stress and (c) a novel 65 kDa protein is associated with small nuclear ribonucleoprotein particles in stress tolerant cells.
... C hdrlec D LANE, Jdnct CHAMPION, Aldn COLMAN, Th~irdppcl C JAMb\, nnd Shalom W APPLEBAUM Lnbo... more ... C hdrlec D LANE, Jdnct CHAMPION, Aldn COLMAN, Th~irdppcl C JAMb\, nnd Shalom W APPLEBAUM Lnbordtory of Developmental Biochemistry ... Subcellular Fructionation and Analysis of N ~ wl ~ ~ - M ade Protrin.s After the incubation, the surrounding medium was col-lected ...
Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the... more Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the efficient conversion of biomass into bioethanol, it is essential that sugars from both the cellulose and hemicellulose fractions of lignocellulose be utilised. We describe the development of a recombinant yeast system for the fermentation of cellulose and xylose, the most abundant pentose sugar in the hemicellulose fraction of biomass. The brewer's yeast Saccharomyces pastorianus was chosen as a host as significantly higher recombinant enzyme activities are achieved, when compared to the more commonly used S. cerevisiae. When expressed in S. pastorianus, the Trichoderma reesei xylose oxidoreductase pathway was more efficient at alcohol production from xylose than the xylose isomerase pathway. The alcohol yield was influenced by the concentration of xylose in the medium and was significantly improved by the additional expression of a gene encoding for xylulose kinase. The xylose redu...
Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during ... more Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during oocyte maturation for use after fertilization and are synthesized in the liver or fat body as a common precursor termed vitellogenin. Hybridization with cloned DNA complementary to vitellogenin messenger RNA has revealed a surprisingly high degree of evolutionary conservation of sequence of vitellogenin genes among insects, amphibians and birds. The synthesis of vitellogenin in vertebrates is directly under the control of oestrogen at the level of gene transcription. In the frog, Xenopus, vitellogenin genes occur as a multigene family, four of which are actively expressed and are grouped as A and B genes. This multiplicity offers a useful system for investigating the possible selective hormonal regulation of expression of individual members of multigene families. When X. laevis vitellogenin genes were activated by oestrogen in the liver of whole animals or in cultures of parenchymal cells, the two groups of expressed genes were not induced in an identical manner in cells from male and female animals. The activation of A and B groups of genes was non-coordinate in male hepatocytes and coordinate in female cells. Prior exposure of male hepatocytes to oestradiol in vivo or in culture caused the pattern of expression to shift to that in female cells. Since the X. laevis oocyte itself does not synthesize vitellogenin in response to oestrogen, an attempt was made to activate its dormant vitellogenin genes by transferring oestrogen-binding proteins from the liver. Preliminary results show that the microinjection into the oocyte of a preparation containing liver receptor-hormone complex led to the synthesis of vitellogenin by the oocyte. Extension of these experiments will not only enable a more precise analysis of the activation of the vitellogenin multigene family to be made but will also provide direct functional evidence for the role played by steroid hormone receptors in regulating gene expression.
Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the... more Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the efficient conversion of biomass into bioethanol, it is essential that sugars from both the cellulose and hemicellulose fractions of lignocellulose be utilised. We describe the development of a recombinant yeast system for the fermentation of cellulose and xylose, the most abundant pentose sugar in the hemicellulose fraction of biomass. The brewer's yeast Saccharomyces pastorianus was chosen as a host as significantly higher recombinant enzyme activities are achieved, when compared to the more commonly used S. cerevisiae. When expressed in S. pastorianus, the Trichoderma reesei xylose oxidoreductase pathway was more efficient at alcohol production from xylose than the xylose isomerase pathway. The alcohol yield was influenced by the concentration of xylose in the medium and was significantly improved by the additional expression of a gene encoding for xylulose kinase. The xylose redu...
Lager yeasts, Saccharomyces pastorianus, are interspecies hybrids between S. cerevisiae and S. eu... more Lager yeasts, Saccharomyces pastorianus, are interspecies hybrids between S. cerevisiae and S. eubayanus and are classified into Group I and Group II clades. The genome of the Group II strain, Weihenstephan 34/70, contains eight so-called 'lager-specific' genes that are located in subtelomeric regions. We evaluated the origins of these genes through bioinformatic and PCR analyses of Saccharomyces genomes. We determined that four are of cerevisiae origin while four originate from S. eubayanus. The Group I yeasts contain all four S. eubayanus genes but individual strains contain only a subset of the cerevisiae genes. We identified S. cerevisiae strains that contain all four cerevisiae 'lager-specific' genes, and distinct patterns of loss of these genes in other strains. Analysis of the subtelomeric regions uncovered patterns of loss in different S. cerevisiae strains. We identify two classes of S. cerevisiae strains: ale yeasts (Foster O) and stout yeasts with patterns...
Journal of immune based therapies and vaccines, 2006
The heat shock protein, Hsp70, has been shown to play an important role in tumour immunity. Vacci... more The heat shock protein, Hsp70, has been shown to play an important role in tumour immunity. Vaccination with Hsp70-peptide complexes (Hsp70-PCs), isolated from autologous tumour cells, can induce protective immune responses. We have developed a novel method to identify synthetic mimic peptides of Hsp70-PCs and to test their ability to activate T-cells. Peptides (referred to as "recognisers") that bind to Hsp70-PCs from the human breast carcinoma cell line, MDA-MB-231, were identified by bio-panning a random peptide M13 phage display library. Synthetic recogniser peptides were subsequently used as bait in a reverse bio-panning experiment to identify potential Hsp70-PC mimic peptides. The ability of the recogniser and mimic peptides to prime human lymphocyte responses against tumour cell antigens was tested by stimulating lymphocytes with autologous peptide-loaded monocyte-derived dendritic cells (DCs). Priming and subsequent stimulation with either the recogniser or mimic p...
Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during ... more Yolk proteins are the most abundant egg proteins in oviparous animals. They are deposited during oocyte maturation for use after fertilization and are synthesized in the liver or fat body as a common precursor termed vitellogenin. Hybridization with cloned DNA complementary to vitellogenin messenger RNA has revealed a surprisingly high degree of evolutionary conservation of sequence of vitellogenin genes among insects, amphibians and birds. The synthesis of vitellogenin in vertebrates is directly under the control of oestrogen at the level of gene transcription. In the frog, Xenopus, vitellogenin genes occur as a multigene family, four of which are actively expressed and are grouped as A and B genes. This multiplicity offers a useful system for investigating the possible selective hormonal regulation of expression of individual members of multigene families. When X. laevis vitellogenin genes were activated by oestrogen in the liver of whole animals or in cultures of parenchymal cell...
The International Journal of Biochemistry & Cell Biology, 2000
Living organisms when subjected to various forms of environmental stress mount a physiological re... more Living organisms when subjected to various forms of environmental stress mount a physiological response to survive the long- and short-term ill-effects of the stress. The stress response may involve selective shut down of non-essential metabolic activities and the repair of macromolecular damage resulting from the stress. Messenger RNA splicing in cultured HeLa cells is one of the processes inhibited by heat stress. Splicing is protected from such inhibition in stress-preconditioned cells that have acquired a tolerant state characterised by increased cell survival and resistance to other environmental stresses. Stress tolerant cells have heat shock proteins (HSPs) that had been induced by the preconditioning process. To examine the biochemical changes induced by stress in the splicing apparatus, we analysed the small nuclear ribonucleoprotein (snRNP) particles associated with spliceosomes in normal, stressed, and stress tolerant cells. We show that (a) the spliceosomal component U4/U5/U6 snRNP particle is disassembled by heat stress into intermediates of splicing assembly, (b) prior induction of stress tolerance protects the structural and functional integrity of snRNPs if cells are subsequently exposed to a severe stress and (c) a novel 65 kDa protein is associated with small nuclear ribonucleoprotein particles in stress tolerant cells.
... C hdrlec D LANE, Jdnct CHAMPION, Aldn COLMAN, Th~irdppcl C JAMb\, nnd Shalom W APPLEBAUM Lnbo... more ... C hdrlec D LANE, Jdnct CHAMPION, Aldn COLMAN, Th~irdppcl C JAMb\, nnd Shalom W APPLEBAUM Lnbordtory of Developmental Biochemistry ... Subcellular Fructionation and Analysis of N ~ wl ~ ~ - M ade Protrin.s After the incubation, the surrounding medium was col-lected ...
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