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PubMed2005

Inhalation toxicity of 1,3-propanediol in the rat.

1,3-Propanediol (504-63-2) was studied to determine the potential effects following repeated inhalation exposures to rats. Rats were exposed 6 hr/day, 5 days/wk for 2 wk (9 exposures) to vapor or vapor/aerosol mixtures of either 0, 41, 650, or 1800 mg 1,3-propanediol/m(3). In vivo responses were observed or measured daily. Clinical pathology and tissue pathology analyses were conducted after the 9th exposure and on half of each group following an 18-day recovery (nonexposure) period. All rats showed normal body weights. No unusual external signs of response were seen, and no deaths were encountered. Clinical pathology (blood counts, serum chemical parameters) and tissue pathology (gross pathology, organ weights, and histopathology) examinations in the 1,3-propanediol exposed rats were similar to those in the unexposed controls. The highest concentration tested, 1800 mg/m(3), which was the highest concentration that could practically be generated, was the no-observed-effect level (NOEL) for this study. 1,3-Propanediol does not appear to pose a significant hazard via inhalation of either the vapor or a vapor/aerosol mixture.

Administration, Inhalation↗

PubMed1987

Oligodeoxyribonucleotides containing 1,3-propanediol as nucleoside substitute.

1,3-Propanediol was protected with one dimethoxytrityl residue and converted into the methoxy- and cyanoethoxyphosphoramidites 2a and 2b, respectively. Solid-phase oligonucleotide synthesis, employing the phosphoramidite 2a resulted in the dodecamers d(CGCGAATTCGCG) (6-9), in which dA or dT residues were replaced by 1,3-propanediol. These oligomers showed a high tendency to form hairpins. Their phosphodiester bonds between the 3'-position of a nucleoside and the propanediol moiety was not cleaved by snake venom phosphodiesterase.

Base Sequence↗

PubMed1983

Use of operon fusions to examine the regulation of the L-1,2-propanediol oxidoreductase gene of the fucose system in Escherichia coli K12.

Escherichia coli K12 growing anaerobically on L-fucose excretes L-1,2-propanediol as a fermentation product whose formation is catalysed by an inducible NAD-linked oxidoreductase. The activity of this enzyme is highly induced only during anaerobic growth. Three bacterial strains bearing a hybrid operon with the structural genes for lactose utilization (lacZYA) fused to the promoter of the propanediol oxidoreductase gene (fucO) were constructed to test whether or not transcriptional control was involved. In contrast to propanediol oxidoreductase of wild-type cells, beta-galactosidase in the phi(fuc-lac) strains was induced by fucose to high levels both aerobically and anaerobically. Data from this work are in accord with the previous report that the enzyme protein (assayed by specific antibodies) was induced both aerobically and anaerobically, but that only in anaerobically grown cells was the oxidoreductase catalytically active. In the present study, we found that the oxidoreductase induced anaerobically in wild-type cells remained enzymically active during aerobic growth in the absence of fucose. On the other hand, wild-type cells grown aerobically in the presence of fucose and then allowed limited anaerobic growth on glucose did not gain any oxidoreductase activity. The mechanism of this post-transcriptional control remains to be discovered.

Alcohol Oxidoreductases↗

PubMed2006

Glycerol, ethylene glycol and propanediol elicit pimaricin biosynthesis in the PI-factor-defective strain Streptomyces natalensis npi287 and increase polyene production in several wild-type actinomycetes.

Production of pimaricin by Streptomyces natalensis ATCC 27448 is elicited by the PI-factor, an autoinducer secreted by the producer strain during the rapid growth phase. Exogenous PI-factor restored pimaricin production in a mutant strain npi287 defective in PI-factor biosynthesis. During purification of the PI-factor, a second pimaricin-inducing fraction different from PI-factor was isolated from the culture broth of wild-type S. natalensis ATCC 27448. After purification by HPLC and analysis by MS and NMR, this active fraction was shown to contain glycerol and lactic acid. Pure glycerol restored pimaricin production in liquid cultures of the autoinducer-defective npi287 mutant. A similar effect was exerted by ethylene glycol, 1,2-propanediol and 1,3-propanediol but not by higher polyalcohols or by glycerol acetate or glycerol lactate esters. Glycerol stimulated (30-270 %) the production of six different polyene macrolide antibiotics by their respective producer strains. Addition of glycerol to the inducer-defective npi287 strain restored pimaricin production but did not result in extracellular or intracellular accumulation of PI-factor. Exogenously added PI-factor was internalized by the cells in the presence of glycerol, and a mixture of both PI-factor and glycerol produced a slightly higher inducing effect on pimaricin production than PI-factor alone. In summary, glycerol, ethylene glycol and propanediol exert a bypass of the PI-factor inducing effect on pimaricin biosynthesis.

Butanols↗

PubMed1984

Dual control of a common L-1,2-propanediol oxidoreductase by L-fucose and L-rhamnose in Escherichia coli.

Anaerobic growth of Escherichia coli on L-fucose or L-rhamnose as the sole source of carbon and energy depends on the regeneration of NAD from NADH by disposing the intermediate L-lactaldehyde as L-1,2-propanediol. The two parallel pathways, with their own permeases and enzymes encoded by two widely separated gene clusters, appear to share a single enzyme that catalyzes the formation of L-1,2-propanediol. Although this oxidoreductase is encoded by a gene at the fuc locus, the enzyme is inducible by both L-fucose and L-rhamnose. The inducibility by L-rhamnose is controlled by a gene at the rha locus with no other known functions, since the aerobic growth rate on L-rhamnose remains normal. L-1,2-Propanediol oxidoreductase activity is inducible only anaerobically, and the effect of the two methylpentoses operates at different levels: L-fucose exerts its influence post-transcriptionally; L-rhamnose exerts its influence transcriptionally.

Aerobiosis↗

PubMed1988

Aerobic excretion of 1,2-propanediol by Salmonella typhimurium.

Salmonella typhimurium excreted the rhamnose fermentation product 1,2-propanediol not only under anaerobic conditions, but also under aerobic conditions. The absence of an aldehyde dehydrogenase enzymatic activity that oxidizes to lactate the lactaldehyde formed in the dissimilation of rhamnose raised the intracellular concentration of the aldehyde which was alternatively reduced to the excretable 1,2-propanediol by a residual propanediol oxidoreductase activity.

Aerobiosis↗

PubMed1989

Constitutive activation of the fucAO operon and silencing of the divergently transcribed fucPIK operon by an IS5 element in Escherichia coli mutants selected for growth on L-1,2-propanediol.

L-1,2-Propanediol is an irretrievable end product of L-fucose fermentation by Escherichia coli. Selection for increased aerobic growth rate on propanediol results in the escalation of basal synthesis of the NAD+-linked oxidoreductase encoded by fucO, a member of the fuc regulon for the utilization of L-fucose. In general, when fucO becomes constitutively expressed, two other simultaneous changes occur: the fucA gene encoding fuculose-1-phosphate aldolase becomes constitutively expressed and the fucPIK operon encoding fucose permease, fucose isomerase, and fuculose kinase becomes noninducible. In the present study, we show that fucO and fucA form an operon which is divergently transcribed from the adjacent fucPIK operon. In propanediol-positive and fucose-negative mutants the cis-controlling region shared by the operons fucAO and fucPIK is lengthened by 1.2 kilobases. DNA hybridization identified the insertion element to be IS5. This element, always oriented in the same direction with the left end (the BglII end) proximal to fucA, apparently causes constitutive expression of fucAO and noninducibility of fucPIK. The DNA of the fucAO operon and a part of the adjacent fucP was sequenced.

Amino Acid Sequence↗

PubMed2001

The alternative electron acceptor tetrathionate supports B12-dependent anaerobic growth of Salmonella enterica serovar typhimurium on ethanolamine or 1,2-propanediol.

Synthesis of cobalamin de novo by Salmonella enterica serovar Typhimurium strain LT2 and the absence of this ability in Escherichia coli present several problems. This large synthetic pathway is shared by virtually all salmonellae and must be maintained by selection, yet no conditions are known under which growth depends on endogenous B12. The cofactor is required for degradation of 1,2-propanediol and ethanolamine. However, cofactor synthesis occurs only anaerobically, and neither of these carbon sources supports anaerobic growth with any of the alternative electron acceptors tested thus far. This paradox is resolved by the electron acceptor tetrathionate, which allows Salmonella to grow anaerobically on ethanolamine or 1,2-propanediol by using endogenously synthesized B12. Tetrathionate provides the only known conditions under which simple cob mutants (unable to make B12) show a growth defect. Genes involved in this metabolism include the ttr operon, which encodes tetrathionate reductase. This operon is globally regulated by OxrA (Fnr) and induced anaerobically by a two-component system in response to tetrathionate. Salmonella reduces tetrathionate to thiosulfate, which it can further reduce to H2S, by using enzymes encoded by the genes phs and asr. The genes for 1,2-propanediol degradation (pdu) and B12 synthesis (cob), along with the genes for sulfur reduction (ttr, phs, and asr), constitute more than 1% of the Salmonella genome and are all absent from E. coli. In diverging from E. coli, Salmonella acquired some of these genes unilaterally and maintained others that are ancestral but have been lost from the E. coli lineage.

Anaerobiosis↗

PubMed2006

Mechanism of hilA repression by 1,2-propanediol consists of two distinct pathways, one dependent on and the other independent of catabolic production of propionate, in Salmonella enterica serovar Typhimurium.

A glycerol dehydrogenase gene was selected as a multicopy suppressor rescuing the reduced hilA expression in the Salmonella enterica serovar Typhimurium cpxA mutant. A substrate of the enzyme, 1,2-propanediol, repressed hilA expression. The 1,2-propanediol-mediated repression at 150 mM, but not that at 300 mM, was abrogated by blocking the catabolism producing propionate from 1,2-propanediol.

Bacterial Proteins↗

PubMed1969

Ferrous-activated nicotinamide adenine dinucleotide-linked dehydrogenase from a mutant of Escherichia coli capable of growth on 1, 2-propanediol.

A nicotinamide adenine dinucleotide-linked dehydrogenase has been partially purified from a mutant of Escherichia coli K-12 able to grow on l-1,2-propanediol as carbon and energy source. This enzyme catalyzes the dehydrogenation at carbon 1 of l-1,2-propanediol, glycerol, 1,3-propanediol, ethylene glycol, and ethyl alcohol. The purified protein requires added ferrous or managanous ions. The V(max) and the apparent K(m) for a given substrate vary with the particular metal used.

Centrifugation, Density Gradient↗

PubMed1989

Production and interconversion of 1,2-propanediol and hydroxyacetone by Escherichia coli.

The anaerobic metabolism of marginally lethal levels of [13C]formaldehyde by Escherichia coli (K12, MU352, CRB, and CR63) was followed in vivo by 13C NMR. The products include 1,2-propanediol. Under aeration, the 1,2-propanediol is converted to hydroxyacetone. The hydroxyacetone is reconverted to 1,2-propanediol when aeration is stopped. The process can be cycled by varying the rate of aeration.

Acetone↗

PubMed1995

A comparison of the acute pathology induced by 3-phenylamino-1,2-propanediol (PAP) and its mono-oleoyl ester in rodents with the toxic oil syndrome in man.

Phenylamino-1,2 propanediol (PAP) and its mono-oleoyl ester have been identified in samples of the cooking oil thought to be responsible for the Toxic Oil Syndrome (TOS) which occurred in Spain in 1981. The acute toxicity of PAP and its mono-oleoyl ester have been examined in rats and mice, after daily administration for periods of up to 14 days to determine whether these compounds could produce any of the pathologies of TOS. Even at the highest dose, the 1-mono-oleoyl ester of 3-phenylamino-1,2 propanediol did not cause any toxicity in rats or mice when given intraperitoneally. 3-Phenylamino-1,2 propanediol, however, was toxic when administered to rats by this route. After 6-10 consecutive daily doses of PAP, at the highest dose administered (350 mg kg-1), all of the rats became unwell. Postmortem examination showed that the major pathology present was massive pulmonary thromboembolism. Further investigations of the toxicity of PAP after intravenous administration showed that it was not directly vasotoxic. The pulmonary thromboembolism seen with intraperitoneally administered PAP was due to the toxic effect of PAP on the mesenteric tissue and blood vessels, causing thrombosis which subsequently embolised the blood vessels in the lung. Intra-gastric administration of PAP caused no toxicity in rats. Comparatively, the pathology seen after intraperitoneal administration of PAP was not thought to be representative of the pathology of the toxic oil syndrome in man.

Animals↗

PubMedDate not supplied

[Redox state of the hepatic cells in rats kept on a diet containing 1,2-propanediol].

A comparative characterization of the redox condition and phosphate potential of the hepatic cells in rats kept on two experimental diets (low- and high-carbohydrate) is given. Intensification of the glucogenesis in the liver of rats kept on a low-carbohydrate diet is determined by lower values of the ratios /NAD+/: (NADH/ and /ATP/:/ADP/P1, the cells acquiring more marked reducting properties. Incorporation of 1,2-propanediol, as a source of metabolized energy, in the composition of the low-carbohydrate diet (20 per cent of the fat content) produces a rise in the level of glycogen and a fall of the liver lipids. The reducing capacity of the cytoplasma diminishes, this being borne out by the ratio of /NAD+/:/NADH/. An increase of the phosphate potential and of the ratio /NAD+/:/NADH/ is in these conditions similar to the one observed with a greater amount of carbohydrates in the diet. The phosphoenol-pyruvate-carboxykinase activity and concentration of malate in the liver diminish with rising concentration of oxaloacetate. When superimposed upon a high-carbohydrate diet 1,2-propanediol causes an increase of the /NAD+/:/NADH/ and /ATP/:P1/ ratios with the lipids content in the liver mounting too. The significance of shifts in the redox state and of the phosphate potential in regulating the 1,2-propanediol metabolism is discussed.

Adenosine Diphosphate↗

PubMed1978

[Studies on the parmacodynamic activity of several drug solvents. 3. 1,2-Propanediol, tetrahydrofurfuryl alcohol-polyethylene glycol ether (THFP), olyoxyethylene sorbitan monooleate (PSM)].

The drug solvents 1,2-propanediol, tetrahydrofurfuryl alcohol polyethylene glycolether (THFP, Tetraglycol), and polyoxyethylene sorbitan monooleate (PSM, Tween 80) were examined for their pharmacodynamic properties in the following tests: i.p. toxicity, "sign pattern", inclined screen test, balance rod test, and potentiation of hexobarbitone sleeping time in mice, spasmolytic activity in the guinea pig isolated ileum, and cardiovascular studies in anaesthetized rats, cats, and dogs including the i.v. toxicity. The solvents showed only small differences in their toxicity in the mouse and rat; PSM, however, was more toxic than 1,2-propanediol and THFP in the cat and dogs. The latter solvent, on the other hand, was the most potent in inducing behavioural changes and in potentiating hexobarbitone sleeping time. In the isolated ileum the solvents showed different spasmolytic potencies, depending on whether histamine, carbachol or BaCl2 was used as a spasmogen. The spasmolytic activity of 1,2-propanediol and THFP is classified as unspecific, whereas PSM seemed to have a specific anticholinergic pattern in the isolated ileum. After i.v. administration in rats, cats, and dogs the solvents caused cardiovascular effects even in very low doses. Based on the pharmacodynamic properties, doses are recommended for each solvent which should not be exceeded without control experiments in the laboratory routine. These tolerable doses do not only depend on the species but also on the test concerned.

Animals↗

PubMed1982

[Synthesis and tests of antibacterial activity of new analogs of d(+)-threo-1-(p-methylsulphonylphenyl)-2-dichloroacetamido-1,3-propanediol (thiamphenicol)].

The synthesis of three new analogues of D(+)-threo-1-(p.methylsulphonylphenyl)-2-dichloroacetamido-1,3-propanediol (thiamphenicol) (I) which are D(--)-threo-2-(p.toluensulfophonamido)-1-(p.methylsulphonylphenyl)-1,3-propanediol (II), D(--)-threo-2-(p.aminobenzensulphonamido)-1-(p.methylsulphonylphenyl)-1,3-propanediol (III), D(--)-threo-2-(p.acetamidobenzensulphonamido)-1-(p.methylsulphonylphenyl)-1,3-propandiol (IV) is reported. The antibacterial activity of the compounds obtained was estimated in comparison with (I) in vitro and the therapeutic activity in vivo by experimental infection of the rat. The results showed the total absence of both types of activity.

Animals↗

PubMed1981

Purification and subunit characterization of propanediol dehydratase, a membrane-associated enzyme.

A new isolation procedure for propanediol dehydratase increases by a factor of about 16 the yield of enzyme obtainable from Klebsiella pneumoniae; the enzyme thus isolated has a specific activity of 95 +/- 4 units/mg. The apoenzyme consists of four subunits with molecular weights of 60 000, 51 000, 29 000, and 15 000 (+/- 5%). In this new procedure, care was taken to prevent the partial proteolysis of the propanediol dehydratase which seems to occur in earlier procedures. The other novel aspect recognizes that the enzyme is associated with the cell membrane. Accordingly, after gentle sonication, the membrane fragments are separated from cytosol, and the enzyme is solubilized by extraction with buffers containing detergent. The 60 000-dalton subunit has been purified and a partial sequence (34 of the 36 N-terminal residues) determined.

Amino Acid Sequence↗

PubMed1977

Mechanism of action of adenosylcobalamin: glycerol and other substrate analogues as substrates and inactivators for propanediol dehydratase--kinetics, stereospecificity, and mechanism.

A number of vicinal diols were found to react with propanediol dehydratase, typically resulting in the conversion of enzyme-bound adenosylcobalamin to cob(II)alamin and formation of aldehyde or ketone derives from substrate. Moreover, all are capable of effecting the irreversible inactivation of the enzyme. The kinetics and mechanism of product formation and inactivation were investigated. Glycerol, found to be a very good substrate for diol dehydratase as well as a potent inactivator, atypically, did not induce cob(II)alamin formation to any detectable extent. With glycerol, the inactivation process was accompanied by conversion of enzyme-bound adenosylcobalamin to an alkyl or thiol cobalamin, probably by substitution of an amino acid chain near the active site for the 5'-deoxy-5'-adenosyl ligand on the cobalamin. The inactivation reaction with glycerol as the inactivator exhibits a deuterium isotope effect of 14, strongly implicating hydrogen transfer as an important step in the mechanism of inactivation. The isotope effect on the rate of product formation was found to be 8.0. Experiments with isotopically substituted glycerols indicate that diol dehydrase distinguishes between "R" and "S" binding conformations, the enzyme-(R)-glycerol complex being predominately responsible for the product-forming reaction, while the enzyme-(S)-glycerol complex results primarily in the activation reaction. Mechanistic implications are discussed. A method for removing enzyme-bound hydroxycobalamin that is nondestructive to the enzyme and a technique for measuring the binding constants of (R)- and (S)-1,2-propanediols are presented.

Adenosine↗

PubMed1998

Kinetic, dynamic, and pathway studies of glycerol metabolism by Klebsiella pneumoniae in anaerobic continuous culture: III. Enzymes and fluxes of glycerol dissimilation and 1,3-propanediol formation.

The initial steps of glycerol dissimilation and 1,3-propanediol (1, 3-PD) formation by Klebsiella pneumoniae anaerobically grown on glycerol were studied by quantifying the in vitro and in vivo activities of enzymes in continuous culture under conditions of steady state and oscillation and during transient phases. The enzymes studied included glycerol dehydrogenase (GDH), glycerol dehydratase (GDHt), and 1,3-propanediol oxidoreductase (PDOR). Three conclusions can be drawn from the steady-state results. First, glycerol concentration in the culture is a key parameter that inversely affects the in vitro activities (concentrations) of all three enzymes, but has a positive effect on their in vivo activities. Growth rate significantly affects the ratio of in vitro and in vivo enzyme activities under low glycerol concentrations, but not under glycerol excess. Second, whereas the flux through the oxidative pathway of glycerol dissimilation is governed mainly by the regulation of in vivo enzyme activity on a metabolic level, the flux through the reductive pathway is largely controlled by the synthesis of enzymes. Third, GDHt is a major rate-liming enzyme for the consumption of glycerol and the formation of 1,3-PD in K. pneumoniae at high glycerol concentrations. Results from oscillating cultures revealed that both in vitro and in vivo activities of the enzymes oscillated. The average values of the in vitro activities during an oscillation cycle agreed well with their corresponding values for nonoscillating cultures under similar environmental conditions. Experiments with step changes in the feed concentration of glycerol demonstrated that growth and product formation are very sensitive to changes of substrate concentration in the culture. This sensitivity is due to the dynamic responses of the genetic and metabolic networks. They should be considered when modeling the dynamics of the culture and attempting to improve the formation of 1,3-PD.

Alcohol Oxidoreductases↗