The polyhydroxyalkanoic acid synthase gene from Chromobacterium violaceum (phaC(Cv)) was cloned and characterized. A 6.3-kb BamHI fragment was found to contain both phaC(Cv) and the polyhydroxyalkanoic acid (PHA)-specific 3-ketothiolase (phaA(Cv)). Escherichia coli strains harboring this fragment produced significant levels of PHA synthase and 3-ketothiolase, as judged by their activities. Whil...

Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-base...

The production of the terpolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate), P(3HB-co-3HV-co-4HB), by Alcaligenes sp. A-04 was investigated to determine the superior biodegradable polymer properties over those of poly(3-hydroxybutyrate), P(3HB), and its copolymers. The highest terpolymer content of 68% (w/w) was produced by Alcaligenes sp. A-04 at 60 h by shake-flask cult...

Alicycliphilus denitrificans strain BC grows anaerobically on acetone with nitrate as electron acceptor. Comparative proteomics of cultures of A. denitrificans strain BC grown on either acetone or acetate with nitrate was performed to study the enzymes involved in the acetone degradation pathway. In the proposed acetone degradation pathway, an acetone carboxylase converts acetone to acetoacetat...

Glucagon has been shown previously to increase further the enhanced tolerance for hypoxia observed in mice with elevated blood ketones. Glucagon is also known to increase blood glucose and to alter directly the metabolism of some (liver) cells. Both the increase in blood glucose and altered cellular metabolism could contribute to the increase in tolerance for hypoxia observed in mice given gluc...

To provide 4-hydroxybutyryl-CoA for poly(3-hydroxybutyrate-co-4-hydroxybutyrate) formation from glutamate in Escherichia coli, an acetyl-CoA:4-hydroxybutyrate CoA transferase from Clostridium kluyveri, a 4-hydroxybutyrate dehydrogenase from Ralstonia eutropha, a gamma-aminobutyrate:2-ketoglutarate transaminase from Escherichia coli, and glutamate decarboxylases from Arabidopsis thaliana or E. c...

1. The rates of formation of acetoacetate and beta-hydroxybutyrate by the isolated perfused rat liver were measured under various conditions. 2. The rates found after addition of butyrate, octanoate, oleate and linoleate were about 100mumoles/hr./g. wet wt. in the liver of starved rats. These rates are much higher than those found with rat liver slices. 3. The differences between the rates give...

Pregnancy toxemia was induced in nine pregnant goat does with twins by the stress of fasting with access to water in late pregnancy to investigate the effect of pregnancy toxemia on immunoglobulins (IgA, IgM, and IgG), cortisol, insulin, thyroid, and growth hormones and their correlations with the plasma levels of glucose and beta-Hydroxybutyrate. Plasma samples were collected at 0, 12, 24, 36,...

Using R-beta-[1-(11)C]hydroxybutyrate and positron emission tomography, we studied the effect of acute hyperketonemia (range 0.7-1.7 micromol/ml) on cerebral ketone body utilization in six nondiabetic subjects and six insulin-dependent diabetes mellitus (IDDM) patients with average metabolic control (HbA(1c) = 8.1 +/- 1.7%). An infusion of unlabeled R-beta-hydroxybutyrate was started 1 h before...

D-beta-hydroxybutyrate, the principal "ketone" body in starving man, displaces glucose as the predominating fuel for brain, decreasing the need for glucose synthesis in liver (and kidney) and accordingly spares its precursor, muscle-derived amino acids. Thus normal 70 kg. man survives 2-3 months of starvation instead of several weeks, and obese man many months to over a year. Without this metab...