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PubMed1978

Purification and properties of an NAD(P)+-linked formaldehyde dehydrogenase from Methylococcus capsulatus (Bath).

Crude soluble extracts of Methylococcus capsulatus strain Bath, grown on methane, were found to contain NAD(P)+-linked formaldehyde dehydrogenase activity. Activity in the extract was lost on dialysis against phosphate buffer, but could be restored by supplementing with inactive, heat-treated extract (70 degrees C for 12 min). The non-dialysable, heat-sensitive component was isolated and purified, and has a molecular weight of about 115000. Sodium dodecyl sulphate gel electrophoresis of the protein suggested there were two equal subunits with molecular weights of 57000. The heat-stable fraction, which was necessary for activity of the heat-sensitive protein, was trypsin-sensitive and presumed to be a low molecular weight protein or peptide. A number of thiol compounds and other common cofactors could not replace the component present in the heat-treated soluble extract. The purified formaldehyde dehydrogenase oxidized three other aldehydes with the following Km values: 0.68 mM (formaldehyde); 0.075 mM (glyoxal); 7.0 mM (glycolaldehyde); and 2.0 mM (DL-glyceraldehyde). NAD+ or NADP+ was required for activity, with Km values of 0.063 and 0.155 mM respectively, and could not be replaced by any of the artificial electron acceptors tested. The enzyme was heat-stable at 45 degrees C for at least 10 min and had temperature and pH optima of 45 degrees C and pH 7.2 respectively. A number of metal-binding agents and substrate analogues were not inhibitory. Thiol reagents gave varying degrees of inhibition, the most potent being p-hydroxymercuribenzoate which at 1 mM gave 100% inhibition. The importance of possessing an NAD(P)+-linked formaldehyde dehydrogenase, with respect to M. capsulatus, is discussed.

Aldehyde Oxidoreductases↗

PubMed1990

The effects of controlled exposure to formaldehyde vapour on spores of Bacillus globigii NCTC 10073.

The effects of exposure of spores of Bacillus globigii NCTC 10073 to controlled levels of formaldehyde vapour under varying environmental conditions are reported. The death rate of the micro-organism varies with the humidity and formaldehyde concentration and can be predicted for conditions within the limits of the information available. A mathematical model for the effects of formaldehyde is proposed which can be used to calculate the effects of known conditions and as the basis of a controlled formaldehyde fumigation process. Results of practical tests of such a process are described.

Bacillus↗

PubMed1985

Biological activity of polynoxylin--an insoluble urea-formaldehyde condensation product.

The antimicrobial activity of polynoxylin, an alkali urea-formaldehyde condensation product, has been examined. The minimum inhibitory concentration (MIC) for 1000 clinical isolates of bacteria and yeasts was in the range 1024-16,384 mg/l. Cidal concentrations of the drug were within one dilution of the corresponding values for MIC, the results suggest a cumulative mode of antimicrobial activity. Formaldehyde, the putative active component of polynoxylin, was released into water from 10% (w/w) cream preparation which gave a maximum yield of 1.56 mg within 6 h. The limited water solubility of polynoxylin, cumulative mode of antimicrobial action and presence of pre-formed formaldehyde in the pharmaceutical preparation, suggest the possibility of sustained activity when applied to skin. The slow solubilization of particulate polynoxylin and gradual liberation of inhibitory degradation products may further enhance the inherent antimicrobial activity afforded by the presence of pre-formed formaldehyde.

Anti-Bacterial Agents↗

PubMed1985

Differential pulse polarographic determination of formaldehyde in stored noxythiolin solutions.

A differential pulse polarographic method has been developed for the determination of formaldehyde, by means of its kinetic current, in noxythiolin solutions. The assay conditions have been optimized so that the noxythiolin decomposition reaction was not affected. The method had the advantage of rapidity with an analysis time of about 10 min per sample. Thus formaldehyde was determined in noxythiolin solutions prepared and stored under typical clinical conditions. The low concentrations of formaldehyde present in all solutions were insufficient to account for the known cidal action of noxythiolin. There must therefore be some doubt that the mode of action of noxythiolin is simply due to formaldehyde produced as a result of the decomposition of noxythiolin in aqueous solution.

Drug Stability↗

PubMed2005

HxlR, a member of the DUF24 protein family, is a DNA-binding protein that acts as a positive regulator of the formaldehyde-inducible hxlAB operon in Bacillus subtilis.

The HxlR protein from Bacillus subtilis belongs to the DUF24 protein family (InterPro No. IPR002577) of unknown function. The hxlR gene that encodes this protein is located upstream of the hxlAB operon. This operon encodes two key enzymes in the ribulose monophosphate pathway that are involved in formaldehyde fixation, 3-hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase. Expression of the hxlAB operon is induced by the presence of formaldehyde. Recombinant HxlR prepared from Escherichia coli showed specific binding to a region of DNA upstream of the hxlAB operon. Using gel-retardation and DNase I footprinting assays, we identified two 25 bp binding regions for HxlR within the upstream DNA. Surface plasmon resonance analyses suggested that two HxlR dimers sequentially bound to the DNA. Finally, we demonstrated that each of the two binding regions for HxlR was necessary for formaldehyde-induced expression of the hxlAB operon in B. subtilis. Thus, we have shown that HxlR is a DNA-binding protein that is necessary for formaldehyde-induced expression of hxlAB in B. subtilis.

Aldehyde-Lyases↗

PubMed1995

Anaphylaxis after dental treatment with a formaldehyde-containing tooth-filling material.

A 67-year-old patient developed systemic reactions after application of a formaldehyde-containing tooth filling. She had a clearly positive RAST result for formaldehyde, whereas skin prick testing and patch tests were negative. Sensitization to formaldehyde appears to have occurred 1 year previously. Induction of formaldehyde allergy may represent a major complication during dental treatment, and assessment of specific IgE should be considered in patients at risk.

Aged↗

PubMed1983

Characterization of formaldehyde-related antibodies encountered in hemodialysis patients at different stages of immunization.

In hemodialysis patients who reuse formaldehyde-sterilized dialysers we found that antibodies agglutinating native NN red cells belonged exclusively to the IgM fraction of immunoglobulins. In the same patients antibodies directed against formaldehyde-altered NN red cells proved to be mainly IgG in addition to IgM. Three stages of formaldehyde-dependent RBC immunization could be distinguished serologically. The production of these antibodies was dependent on the time of hemodialysis treatment. We found antibodies which could bind complement in the presence of soluble antigen. These antibodies are supposed to damage the patient's red cells immediately after contact to minute amounts of formaldehyde during hemodialysis.

Blood Group Incompatibility↗

PubMed1977

Investigation of the binding of Escherichia coli RNA polymerase to DNA from bacteriophages T2 and T7 by kinetic formaldehyde method and electron microscopy.

The complexes of T2 DNA with RNA polymerase of Escherichia coli were studied by two methods: kinetic formaldehyde method with preliminary fixation of complexes with low formaldehyde concentrations, and electron microscopy. For electron-microscopic investigations the effect of different conditions of formaldehyde fixation for DNA-RNA-polymerase complexes was studied and optimal fixation conditions were found. The suggested fixation method for DNA-RNA-polymerase complexes allows investigation of RNA polymerase molecule distribution on DNA in a wide range of conditions (ionic strength of the solution, weight ration of enzyme to DNA etc.). The comparison of the concentration of RNA polymerase molecules bound to DNA, determined by electron microscopy, and the concentration of defects in DNA as determined by the kinetic formaldehyde method, showed their coincidence. The electron-microscopic procedure was used to make maps of RNA polymerase distribution on T7 DNA. A correlation between the binding regions of the enzyme and the genetic map of early DNA T7 region was found.

Binding Sites↗

PubMed1981

Residual formaldehyde in dialyzers: quantity, location, and the effect of different methods of rinsing.

When formalin-sterilized dialyzers were rinsed by our standard technique (similar to that used in many other dialysis centres) undesirable concentrations of formaldehyde were found in the dialyzers at the start of dialysis. When the technique was modified by passing part of the saline through the blood compartment immediately before connection and discarding the saline left in the dialyzer at the time of connection, the concentration of formaldehyde infused into the patient fell below 2 micrograms/ml. However, the dialyzers still contained up to 13 mg of formaldehyde which leached slowly from the dialyzer during simulated dialysis. Some residual formaldehyde was found in several components of the dialyzer but the great majority was contained in the cellulose membrane.

Disinfectants↗

PubMed1995

A novel formaldehyde oxidation pathway in methylotrophic yeasts: methylformate as a possible intermediate.

A considerable amount of methylformate accumulated in the culture medium of methanol-grown methylotrophic yeasts. Methylformate is considered as an intermediate in a novel formaldehyde oxidation pathway. Through investigations with Pichia methanolica, methylformate formation was found to be catalysed by a new type of alcohol dehydrogenase, which was named methylformate synthase. When cells were grown on a relatively high concentration of methanol or exposed to a high concentration of formaldehyde, formation of methylformate was enhanced and the level of methylformate synthase in the cells increased. How methylformate synthase is involved in formaldehyde oxidation and formaldehyde detoxification is discussed.

Alcohol Dehydrogenase↗

PubMed1988

Patch testing with a mixture of 2 phenol-formaldehyde resins.

1310 patients were routinely patch tested with a paratertiary-butylphenol-formaldehyde resin (PTBP-F-R), a resol resin based on phenol and formaldehyde (P-F-R-2), and a mixture of these 2 resins. Approximately 2.5 times more patients with contact allergy to phenol-formaldehyde resins were diagnosed when routinely patch tested with P-F-R-2 in addition to PTBP-F-R. Although patch testing with a mixture of both resins was not as good as patch testing with the 2 resins separately, it was better than testing only with PTBP-F-R, since 1.6 times more patients with contact allergy to phenol-formaldehyde resins were still diagnosed. P-F-R-2 is therefore recommended for routine patch testing, preferably as a separate patch test but otherwise as a mixture with PTBP-F-R.

Dermatitis, Contact↗

PubMed1999

Determination of formaldehyde emission with field and laboratory emission cell (FLEC)--recovery and correlation to the chamber method.

The formaldehyde emission from wood-based building materials is usually determined in large chambers at a defined temperature, humidity and ventilation rate. In this article, a simpler method, the Field and Laboratory Emission Cell (FLEC), is described for determination of the formaldehyde emission and it is compared with the traditional chamber method. The formaldehyde from FLEC is collected on a silicagel cartridge impregnated with 2,4-dinitrophenylhydrazine (DNPH) and analysed with HPLC. The FLEC is easier to operate, requires a smaller sample, fewer analyses and is also more flexible than the chamber method. The emissions from different parts of a sample can be measured. Another advantage is that the equipment can be used to determine the volatile organic compounds (VOCs) emission at the same time. The FLEC method gives a good correlation to the chamber method for different building products. It also gives a good recovery. An average recovery of 98% was achieved, when two different FLEC-cells were tested with known formaldehyde sources with emissions of 0.06-0.7 mg/m2h.

Air Pollution, Indoor↗

PubMed1976

Effect of formaldehyde-containing drugs on human dental pulp evaluated by enzyme histochemical technique.

The in vivo effect of formaldehyde on pulp tissue in short-term studies cannot be established by using routine histologic techniques because the tissue is exposed to a fixative in vivo as well as during the histologic preparation. The pulps of permanent premolars were amputated and zinc oxide with 4% formaldehyde or formocresol was used as wound dressing. The observation periods varied from 1 to 16 d. After extraction the teeth were freeze-sectioned, freeze-dried and then incubated for histochemical demonstration of some oxidative and hydrolytic enzymes. A demarcated border between apically stained and cervically nonstained pulp tissue was found in sections incubated for oxidative enzymes. When formocresol, which has a high concentration of formaldehyde, was used, the border was situated closer to the apex. This was also the case when the observation period was increased. The incubation for lactate dehydrogenase gave a high staining intensity. Thus the use of frozen sections in combination with the histochemical method for the demonstration of lactate dehydrogenase appears to be suitable for the study of the penetration of formaldehyde in pulp tissue in short-term studies.

Acid Phosphatase↗

PubMed1983

Formaldehyde damage to DNA and inhibition of DNA repair in human bronchial cells.

Cultured bronchial epithelial and fibroblastic cells from humans were used to study DNA damage and toxicity caused by formaldehyde. Formaldehyde caused the formation of cross-links between DNA and proteins, caused single-strand breaks in DNA, and inhibited the resealing of single-strand breaks produced by ionizing radiation. Formaldehyde also inhibited the unscheduled DNA synthesis that occurs after exposure of cells to ultraviolet irradiation or to benzo[a]pyrene diolexpoxide but at doses substantially higher than those required to inhibit the resealing of x-ray-induced single-strand breaks. Therefore, formaldehyde could exert its mutagenic and carcinogenic effects by both damaging DNA and inhibiting DNA repair.

Bronchi↗

PubMed1997

Purification and properties of methyl formate synthase, a mitochondrial alcohol dehydrogenase, participating in formaldehyde oxidation in methylotrophic yeasts.

Methyl formate synthase, which catalyzes methyl formate formation during the growth of methylotrophic yeasts, was purified to homogeneity from methanol-grown Candida boidinii and Pichia methanolica cells. Both purified enzymes were tetrameric, with identical subunits with molecular masses of 42 to 45 kDa, containing two atoms of zinc per subunit. The enzymes catalyze NAD(+)-linked dehydrogenation of the hydroxyl group of the hemiacetal adduct [CH2(OH)OCH3] of methanol and formaldehyde, leading to the formation of a stoichiometric amount of methyl formate. Although neither methanol nor formaldehyde alone acted as a substrate for the enzymes, they showed simple NAD(+)-linked alcohol dehydrogenase activity toward aliphatic long-chain alcohols such as octanol, showing that they belong to the class III alcohol dehydrogenase family. The methyl formate synthase activity of C. boidinii was found in the mitochondrial fraction in subcellular fractionation experiments, suggesting that methyl formate synthase is a homolog of Saccharomyces cerevisiae Adh3p. These results indicate that formaldehyde could be oxidized in a glutathione-independent manner by methyl formate synthase in methylotrophic yeasts. The significance of methyl formate synthase in both formaldehyde resistance and energy metabolism is also discussed.

Alcohol Oxidoreductases↗

PubMed2003

Formaldehyde fixation contributes to detoxification for growth of a nonmethylotroph, Burkholderia cepacia TM1, on vanillic acid.

During bacterial degradation of methoxylated lignin monomers, such as vanillin and vanillic acid, formaldehyde is released through the reaction catalyzed by vanillic acid demethylase. When Burkholderia cepacia TM1 was grown on vanillin or vanillic acid as the sole carbon source, the enzymes 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI) were induced. These enzymes were also expressed during growth on Luria-Bertani medium containing formaldehyde. To understand the roles of these enzymes, the hps and phi genes from a methylotrophic bacterium, Methylomonas aminofaciens 77a, were introduced into B. cepacia TM1. The transformant strain constitutively expressed the genes for HPS and PHI, and these activities were two- or threefold higher than the activities in the wild strain. Incorporation of [14C]formaldehyde into the cell constituents was increased by overexpression of the genes. Furthermore, the degradation of vanillic acid and the growth yield were significantly improved at a high concentration of vanillic acid (60 mM) in the transformant strain. These results suggest that HPS and PHI play significant roles in the detoxification and assimilation of formaldehyde. This is the first report that enhancement of the HPS/PHI pathway could improve the degradation of vanillic acid in nonmethylotrophic bacteria.

Aldehyde-Lyases↗

PubMed1973

New formaldehyde base disinfectants.

Preparations of formaldehyde in various organic liquids-ethylene glycol, glycerol, and propylene glycol-serve as effective disinfectants towards microbial vegetative cells and spores. This disinfection is a temperature-dependent process and is manifest when these formaldehyde base disinfectants are dissolved in water. The irritating vapors associated with formaldehyde disinfection are not present in either of these new formaldehyde base disinfectants or in aqueous solutions of them.

Bacillus↗

PubMed2003

Formaldehyde-detoxifying role of the tetrahydromethanopterin-linked pathway in Methylobacterium extorquens AM1.

The facultative methylotroph Methylobacterium extorquens AM1 possesses two pterin-dependent pathways for C(1) transfer between formaldehyde and formate, the tetrahydrofolate (H(4)F)-linked pathway and the tetrahydromethanopterin (H(4)MPT)-linked pathway. Both pathways are required for growth on C(1) substrates; however, mutants defective for the H(4)MPT pathway reveal a unique phenotype of being inhibited by methanol during growth on multicarbon compounds such as succinate. It has been previously proposed that this methanol-sensitive phenotype is due to the inability to effectively detoxify formaldehyde produced from methanol. Here we present a comparative physiological characterization of four mutants defective in the H(4)MPT pathway and place them into three different phenotypic classes that are concordant with the biochemical roles of the respective enzymes. We demonstrate that the analogous H(4)F pathway present in M. extorquens AM1 cannot fulfill the formaldehyde detoxification function, while a heterologously expressed pathway linked to glutathione and NAD(+) can successfully substitute for the H(4)MPT pathway. Additionally, null mutants were generated in genes previously thought to be essential, indicating that the H(4)MPT pathway is not absolutely required during growth on multicarbon compounds. These results define the role of the H(4)MPT pathway as the primary formaldehyde oxidation and detoxification pathway in M. extorquens AM1.

Carbon↗