摘要:
Polyhydroxyalkanoates (PHAs) from which pyrogen has been removed are provided for use in numerous biomedical applications. PHAs which have been chemically modified to enhance physical and/or chemical properties, for targeting or to modify biodegradability or clearance by the reticuloendothelial system (RES), are described. Methods for depyrogenating PHA polymers prepared by bacterial fermentation processes are also provided, wherein pyrogens are removed from the polymers without adversely impacting the polymers' inherent chemical structures and physical properties. PHAs with advantageous processing characteristics, including low melting points and/or solubility in non-toxic solvents, are also described. PHAs are provided which are suitable for use in in vivo applications such as in tissue coatings, stents, sutures, tubing, bone and other prostheses, bone or tissue cements, tissue regeneration devices, wound dressings, drug delivery, and for diagnostic and prophylactic uses. Properties which are selected for include degradability, elasticity, inclusion of functional groups or derivatized groups, which can in turn be used to attach targeting agents, and bioadhesion.
摘要:
Novel genes encoding P. pastoris ARG1, ARG2, ARG3, HIS1, HIS2, HIS5 and HIS6 are disclosed. A method for inactivating alternately at least two biosynthetic pathways in a methylotrophic yeast is provided. A method for producing and selecting yeast strains characterized as being capable of genetic integration of heterologous sequences into the host genome using the genes involved in the biosynthetic pathways is also disclosed.
摘要:
Purification of recombinant proteins is performed by expressing in a host cell a fusion protein comprising: (a) a product protein domain, (b) an intein, and (c) at least one aggregator protein domain, wherein the aggregator protein domain comprises a protein that is capable of specific association with granules of polyhydroxyalkanoate (PHA).
摘要:
Polyhydroxyalkanoates (PHAs) from which pyrogen has been removed are provided. PHAs which have been chemically modified to enhance physical and/or chemical properties, for targeting or to modify biodegradability or clearance by the reticuloendothelial system (RES), are described. Methods for depyrogenating PHA polymers prepared by bacterial fermentation processes are also provided, wherein pyrogens are removed from the polymers without adversely impacting the polymers' inherent chemical structures and physical properties. PHAs with advantageous processing characteristics, including low melting points and/or solubility in non-toxic solvents, are also described. The PHAs are suitable for use in in vivo applications such as in tissue coatings, stents, sutures, tubing, bone, other prostheses, bone or tissue cements, tissue regeneration devices, wound dressings, drug delivery, and for diagnostic and prophylactic uses.
摘要:
Polyhydroxyalkanoates (PHAs) from which pyrogen has been removed are provided for use in numerous biomedical applications. PHAs which have been chemically modified to enhance physical and/or chemical properties, for targeting or to modify biodegradability or clearance by the reticuloendothelial system (RES), are described. Methods for depyrogenating PHA polymers prepared by bacterial fermentation processes are also provided, wherein pyrogens are removed from the polymers without adversely impacting the polymers' inherent chemical structures and physical properties. PHAs with advantageous processing characteristics, including low melting points and/or solubility in non-toxic solvents, are also described. PHAs are provided which are suitable for use in in vivo applications such as in tissue coatings, stents, sutures, tubing, bone and other prostheses, bone or tissue cements, tissue regeneration devices, wound dressings, drug delivery, and for diagnostic and prophylactic uses. Properties which are selected for include degradability, elasticity, inclusion of functional groups or derivatized groups, which can in turn be used to attach targeting agents, and bioadhesion.
摘要:
Novel genes encoding P. pastoris ARG1, ARG2, ARG3, HIS1, HIS2, HIS5 and HIS6 are disclosed. A method for inactivating alternately at least two biosynthetic pathways in a methylotrophic yeast is provided. A method for producing and selecting yeast strains characterized as being capable of genetic stable integration of heterologous sequences into the host genome using the genes involved in the biosynthetic pathways is also disclosed.
摘要:
Cell lines having genetically modified glycosylation pathways that allow them to carry out a sequence of enzymatic reactions, which mimic the processing of glycoproteins in humans, have been developed. Recombinant proteins expressed in these engineered hosts yield glycoproteins more similar, if not substantially identical, to their human counterparts. The lower eukaryotes, which ordinarily produce high-mannose containing N-glycans, including unicellular and multicellular fungi are modified to produce N-glycans such as Man5GlcNAc2 or other structures along human glycosylation pathways. This is achieved using a combination of engineering and/or selection of strains which: do not express certain enzymes which create the undesirable complex structures characteristic of the fungal glycoproteins, which express exogenous enzymes selected either to have optimal activity under the conditions present in the fungi where activity is desired, or which are targeted to an organelle where optimal activity is achieved, and combinations thereof wherein the genetically engineered eukaryote expresses multiple exogenous enzymes required to produce “human-like” glycoproteins.
摘要:
Cell lines having genetically modified glycosylation pathways that allow them to carry out a sequence of enzymatic reactions, which mimic the processing of glycoproteins in humans, have been developed. Recombinant proteins expressed in these engineered hosts yield glycoproteins more similar, if not substantially identical, to their human counterparts. The lower eukaryotes, which ordinarily produce high-mannose containing N-glycans, including unicellular and multicellular fungi are modified to produce N-glycans such as Man5GlcNAc2 or other structures along human glycosylation pathways. This is achieved using a combination of engineering and/or selection of strains which: do not express certain enzymes which create the undesirable complex structures characteristic of the fungal glycoproteins, which express exogenous enzymes selected either to have optimal activity under the conditions present in the fungi where activity is desired, or which are targeted to an organelle where optimal activity is achieved, and combinations thereof wherein the genetically engineered eukaryote expresses multiple exogenous enzymes required to produce “human-like” glycoproteins.
摘要:
Cell lines having genetically modified glycosylation pathways that allow them to carry out a sequence of enzymatic reactions, which mimic the processing of glycoproteins in humans, have been developed. Recombinant proteins expressed in these engineered hosts yield glycoproteins more similar, if not substantially identical, to their human counterparts. The lower eukaryotes, which ordinarily produce high-mannose containing N-glycans, including unicellular and multicellular fungi are modified to produce N-glycans such as Man5GlcNAc2 or other structures along human glycosylation pathways. This is achieved using a combination of engineering and/or selection of strains which: do not express certain enzymes which create the undesirable complex structures characteristic of the fungal glycoproteins, which express exogenous enzymes selected either to have optimal activity under the conditions present in the fungi where activity is desired, or which are targeted to an organelle where optimal activity is achieved, and combinations thereof wherein the genetically engineered eukaryote expresses multiple exogenous enzymes required to produce “human-like” glycoproteins.
摘要:
Polyhydroxyalkanoate (PHA) that contains a pyrogen such as endotoxin due to a process of producing the PHA is treated to remove the pyrogen by a process that does not affect the inherent chemical and physical properties of the PHA to obtain a biocompatible PHA. PHA produced by fermentation with a Gram negative bacteria can be treated with an oxidizing agent such as hydrogen peroxide or benzoyl peroxide to reduce the endotoxin content to less than 20 endotoxin units/gram of PHA to produce PHA that does not elicit an acute inflammatory response when implanted in an animal. The PHA may have a melting point or glass transition temperature less than 136° C., and can be chemically modified or derivatized such as by covalently coupling an attachment or targeting molecule. The PHA may be used to form various medical devices, and can be used for in vivo applications including tissue coatings, stents, sutures, tubing, bone and other prostheses, bone and tissue cements, tissue regenerating devices, wound dressings, drug delivery, and for diagnostic and prophylactic uses.