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PubMed2006

[Optimizing culture system of mouse marrow mesenchymal stem cells in vitro and investigating effect of alcohol and acetaldehyde on the cells].

OBJECTIVE: To optimize the in vitro culture system of C57/BL6 marrow mesenchymal stem cells (MSCs) and to investigate the effect of alcohol and acetaldehyde on MSCs. METHODS: The MSCs were isolated from the femur marrow of C57/BL6 mice and were cultured in the optimized system, so that highly-purified MSCs were harvested and identified by immunohistochemistry. Then, MSCs were cultured in the medium containing alcohol or its metabolic product acetaldehyde, with the following concentration groups: alcohol 5.7, 17.0, 50.0, 100.0 and 150.0 mmol/L; acetaldehyde 4.5, 0.9, 0.18, 0.036, 0.0072, 0.00144, 0.000288 mmol/L. MSCs were cultured with alpha-MEM as the control group. After 3 days, their proliferation activity was measured by the MTT method. RESULTS: MSCs within 6 passages had a good stability and a high proliferation activity. They were identified to express CD90 but no CD34. The MTT assay showed that alcohol at the concentration greater than 100.0 mmol/L and acetaldehyde at the concentration greater than 4.5 mmol/L could inhibit proliferation of MSCs (P < 0.05). But the proliferation activity might rise with an increase in the acetaldehyde concentration smaller than 0.18 mmol/L (P < 0.05). CONCLUSION: The optimized culture system can effectively isolate and culture MSCs. Both alcohol and acetaldehyde can inhibit proliferation of MSCs but toxicity of acetaldehyde is more serious.

Acetaldehyde↗
PubMedDate not supplied

Inhibition of the metabolism of ethyl carbamate by acetaldehyde.

Ethyl carbamate is an animal carcinogen when administered in large doses; it is naturally present in minute concentrations in fermented foods and beverages. Previous studies from this laboratory have demonstrated that ethanol, in vivo, inhibits the metabolism of ethyl carbamate in mice, but the enzyme system has not been identified. In an effort to further characterize the enzyme system responsible, the metabolic products of ethanol metabolism were studied to determine whether ethanol or either of its metabolites is inhibitory. Acetaldehyde (400 mg/kg) is a potent inhibitor of ethyl carbamate metabolism for about 2 hr in vitro, but sodium acetate is not. Paraldehyde (250 mg/kg) has a slower onset and longer duration of inhibition, suggesting that its conversion to acetaldehyde produces the inhibitory molecule. Disulfiram (200 mg/kg) has a prolonged inhibitory effect; this effect is enhanced and extended when the disulfiram is combined with acetaldehyde (400 mg/kg). D-Penicillamine, given in a regimen of 1.2 g/kg 0.5 hr before and 0.6 g/kg 1.5 and 3.5 hr after ethyl carbamate, is not inhibitory; however, it abolishes the inhibitory effect of acetaldehyde, presumably from sequestration of acetaldehyde. These studies demonstrate that acetaldehyde is an inhibitor of the metabolism of ethyl carbamate and suggest that acetaldehyde is one, and perhaps the only, molecule responsible for the inhibition seen when ethanol is administered to mice. In vitro incubation studies determined that ethyl carbamate was not metabolized by human plasma.

Acetaldehyde↗
PubMed1987

Elimination kinetics of ethanol and acetaldehyde in healthy men during the calcium carbimide-alcohol flush reaction.

In a crossover design experiment, we investigated the elimination kinetics of ethanol and acetaldehyde during the calcium carbimide (CC)-alcohol flush reaction. Ten healthy men swallowed a tablet of calcium carbimide (50 mg) or placebo and about 2 hours later drank 0.25 g/kg ethanol within 5 min. The pulmonary blood concentrations of ethanol and acetaldehyde were estimated indirectly by analysis of end-expired alveolar air. The onset of facial flushing and associated cardiovascular response coincided with the peak concentrations of ethanol and acetaldehyde in blood. The speed of absorption of alcohol was faster in subjects treated with CC. A smaller volume of distribution of ethanol was evident after pretreatment with CC; 0.636 L/kg compared with 0.675 L/kg after placebo. The rate of elimination of ethanol from blood was about 5% slower in subjects given the CC tablet. The disposition kinetics of acetaldehyde were markedly different when aldehyde dehydrogenase (ALDH) was inhibited. The maximum blood-levels of acetaldehyde ranged from 40-242 microM compared with 1.7-6.5 microM in the placebo control experiments. The elimination half-life of acetaldehyde after CC treatment ranged from 18-31 min. Our results do not support a significant role of acetaldehyde in regulating in-vivo metabolism of ethanol in humans.

Acetaldehyde↗
PubMed1986

Reaction of acetaldehyde with hemoglobin.

Acetaldehyde reacted with hemoglobin at neutral pH and 37 degrees C to form adducts that were stable to dialysis and that were not reduced by sodium borohydride. Hemoglobin tetramers having 2, 3, and probably 4 molar eq of bound aldehyde were isolated by cation exchange chromatography. The sites of attachment of the aldehyde were the free amino groups of the N-terminal valine residues of the alpha and beta chains of hemoglobin. Derivatization of the beta chains caused a greater increase in the acidity of the hemoglobin than did derivatization of the alpha chains. Derivatization of the beta chains was also preferred over that of the alpha chains. Acetaldehyde derivatives of the N-terminal octapeptide of hemoglobin S (beta sT-1 peptide), Val-Gly-Gly, and tetraglycine were formed readily, contained 1 M eq of acetaldehyde/mol of peptide, and were not reduced by sodium borohydride. In contrast, Ala-Pro-Gly failed to form a 1:1 adduct with acetaldehyde. 13C NMR analysis of the peptide adducts formed with [1,2-13C]acetaldehyde indicated that tetrahedral diastereomeric derivatives were produced. The 13C chemical shifts of the adducts formed between hemoglobin and [1,2-13C]acetaldehyde were identical to those of the peptide adducts although resonances from the individual diastereomeric adducts at each hemoglobin site could not be resolved. The results cited above as well as other evidence indicate that acetaldehyde reacts with the amino termini of hemoglobin to form stable cyclic imidazolidinone derivatives. An exchange of acetaldehyde residues between peptides was also documented.

Acetaldehyde↗
PubMed1985

Covalent binding of acetaldehyde to hepatic proteins during ethanol oxidation.

Acetaldehyde production and the radiolabeling of hepatic proteins were determined in rat liver slices incubated with 14C-ethanol (10 mmol/L). Significant labeling of hepatic proteins occurred in the presence of protein synthesis inhibitors, indicating that, under these conditions, the radiolabeling of protein did not occur via de novo protein synthesis. Additional experiments indicated that the major source of protein-bound radioactivity derived from 14C-ethanol oxidation was the formation of 14C-acetaldehyde adducts with proteins. This conclusion was made from observations that pyrazole, an inhibitor of ethanol oxidation and, therefore, acetaldehyde formation, decreased radiolabeling of protein, whereas cyanamide, which elevated hepatic acetaldehyde levels, markedly increased the labeling of protein. Furthermore, L-cysteine, which can bind acetaldehyde and, therefore, act as an acetaldehyde trap, substantially reduced protein-bound radioactivity. It was also demonstrated that acetaldehyde formed both stable and unstable adducts with hepatic proteins and that unstable adducts may undergo conversion to form stable adducts during incubation.

Acetaldehyde↗
PubMedDate not supplied

The effect of ethanol upon early development in mice and rats. VI. In vivo effect of acetaldehyde upon preimplantation stages in rats.

In completion of the previously outlined "experimental alcohol blastopathy", the role of acetaldehyde in the induction of preimplantation pathological changes in rat embryos has been controlled. Two experimental models were used: the direct administration of acetaldehyde by gavage and the blockage of acetaldehyde metabolization by ANTALCOL (an aldehyde-dehydrogenase blocking compound). The main results were as follows: The exogenous acetaldehyde in the blood of pregnant animals has an obvious effect upon the developmental rate during the late preimplantation period (retarding segmentation, blastulation), and in one of the experimental models upon the oviductal-uterine migration rate. The increase of the blood acetaldehyde level by blockage of its further metabolization has a more marked effect as compared with the direct intravenous administration of the substance. According to our previous observations the intravenous application of ethanol on the same day (day 4) has no such effect. The direct noxious influence upon the developing preimplantation embryos (fragmentation) of the increased level of acetaldehyde obtained by ANTALCOL treatment is similar but more marked than this effect obtained previously by ethanol administration. The same effect observed after the direct administration of the substance is less marked than the effect of ANTALCOL treatment but more marked than the effect of intravenous ethanol administration. These results attest that acetaldehyde may contribute (alone or together with the effect of ethanol) to the induction of "experimental alcohol blastopathy". The less marked action of the substance proper introduced into the blood stream may be due--in our opinion--to its possible alteration during the period between distillation and application.

Acetaldehyde↗
PubMed1984

Alteration of acetaldehyde metabolism in carbon tetrachloride-intoxicated rat liver: analysis using liver perfusion system.

The heptic metabolism of acetaldehyde in carbon tetrachloride (CCl4)-intoxicated rats was studied using a non-recirculating haemoglobin-free liver-perfusion system. Acetaldehyde uptake by the liver from acutely CCl4-treated animals (4.16 mmol/kg,i.p.) at 24 hr after the treatment was not significantly altered, whereas that by the liver from chronically CCl4-treated animals (2.08 mmol/kg,i.p., twice a week, for 8-12 weeks) was decreased by approximately 50% when it was determined in the presence of 0.01-5 mM acetaldehyde. In liver from rats chronically intoxicated with CCl4, the following important biochemical changes were observed: (1) The activity of low Km aldehyde dehydrogenase (ALDH) in hepatic mitochondria was decreased by approximately 75%. (2) The basal levels of the lactate/pyruvate (cytosolic [NADH]/[NAD+]) ratio as well as the beta-hydroxybutyrate/acetoacetate (mitochondrial [NADH]/[NAD+]) ratio were elevated by more than 2-fold. (3) Mitochondrial NADH oxidation was also reduced by approximately 35% of the control level. (4) The basal level of hepatic oxygen uptake was attenuated by approximately 50%, and the infusion of acetaldehyde (0.01-5.0 mM) caused a further decrease in the uptake. (5) The rate of ethanol production from acetaldehyde by the catalytic action of alcohol dehydrogenase was found to be unaltered when low concentrations of acetaldehyde (0.01-0.2 mM) were used, whereas a significant suppression of the rate of ethanol production was detected in the presence of high concentrations of acetaldehyde (0.6-5 mM).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde↗
PubMed1978

Effects of acetaldehyde on electrical and mechanical activities of guinea-pig taenia coli.

The effect of acetaldehyde on the electrical and mechanical activities of the isolated segment of taenia coli from guinea-pigs has been studied using a sucrose-gap method. Application of acetaldehyde produces relaxation of the muscle, which is accompanied by reduction or cessation of spontaneous spike activity and hyperpolarization of the membrane. The hyperpolarization becomes smaller with lowering the temperature. These actions of acetaldehyde are not modified by adrenergic and cholinergic receptor blocking agents nor by tetrodotoxin and ouabain. Acetaldehyde also reduces the evoked activities produced by KCl, BaCl2, acetylcholine or electrical stimulation. The nonadrenergic inhibitory junction potential is reduced by acetaldehyde. When external Ca++ is replaced with Sr++ or Ba++, the action of acetaldehyde is suppressed. Addition of Mn++ eliminates the action of the aldehyde. Acetaldehyde relaxes the muscle when administered after fully developed membrane depolarization induced by K2SO4.

Acetaldehyde↗
PubMed1982

[Catecholamines in the mechanism of the cardionecrotic action of acetaldehyde].

Administration of acetaldehyde to rats by inhalation or intraperitoneally (in repeated doses) provokes an emergence of micronecroses in the myocardium. Administration of acetaldehyde in a dose causing no injury to the myocytes potentiates the cardionecrotic action of adrenalin. Pretreatment with L-DOPA potentiates while that of L-alpha-methyl-DOPA or alpha-methyl-p-tyrosine averts the necrosogenous action of acetaldehyde. Under isolated heart perfusion, acetaldehyde administered in the concentrations that exceeded 2-fold and more those in the blood in experiments in vivo had no necrosogenous action. The degree of the adrenalin-induced lesions of the isolated myocardium remained unchanged in the presence of acetaldehyde. It is assumed that the cardionecrotic effect of acetaldehyde is mediated by catecholamines and is effected by stimulation of biogenic amine release from neurons and chromaffin tissue, and is not linked with direct acetaldehyde effect on the realization of the alterative action of catecholamines.

Acetaldehyde↗
PubMed1982

Ethanol as a discriminative stimulus: effects of cyanamide, acetaldehyde and chlormethiazole.

Two groups of gerbils were trained to discriminate between either 2 g/kg of ethanol (ETOH) and saline or 2 g/kg of ETOH and 1 g/kg of ETOH. Acetaldehyde and a combination of cyanamide, an aldehyde dehydrogenase inhibitor, plus ETOH were tested to determine if augmented levels of acetaldehyde would enhance ETOH-like responses. The CNS depressant drug chlormethiazole (CMZ) was also tested, separately and in combination with ETOH. The effects of ETOH and acetaldehyde were also tested in an open-field (O--F). Some effect of acetaldehyde (ED50 = 160 mg/kg) was observed in the group trained to discriminate between saline and 2 g/kg of ETOH (ED50 = 800 mg/kg) but not in the group trained to discriminate between 1 and 2 g/kg ETOH. Cyanamide (50 mg/kg) given before 1 g/kg of ETOH did not markedly change the amount of ETOH (2 g/kg) appropriate responses as compared to the saline control. The percentage of ETOH (2 g/kg) appropriate choices increased after testing combinations of CMZ and ETOH as compared to testing either drug separately. ETOH stimulated ambulation (horizontal locomotor activity), whereas acetaldehyde resulted in a dose related decrease of all the behaviour patterns recorded in the O--F test. The major conclusions from these studies are that the behavioural pharmacology of acetaldehyde differs from that of ETOH, that acetaldehyde plays only a limited role in the discriminative stimulus effects of ethanol in gerbils, and that the stimulus effects of ETOH and CMZ are additive.

Acetaldehyde↗
PubMed1982

The effect of ethanol and/or acetaldehyde on the incorporation of U14C-glucose into human umbilical artery lipids.

The effect of ethanol, acetaldehyde and a combination of ethanol and acetaldehyde added in vitro was determined on their abilities to alter conversion of glucose to lipid. When human umbilical arteries were perfused with acetaldehyde at a 0.5% concentration, a significant reduction (p less than 0.05) of 14C incorporation into lipid was observed. This reduction was found to be the result of depressed incorporation of glucose into phospholipid (PL) and triacylglycerides (TG). Acetaldehyde at a concentration of 0.25% appeared to depress incorporation; however, this was not significant. Acetaldehyde plus ethanol at final equal concentrations of 0.25%, 0.5% and 1.0% had no effect on incorporation of U14 C-glucose into lipid. Ethanol at concentrations of 0.5%, 0.25% and 0.125% had no effect on the incorporation of U14 C-glucose into lipid. The study suggests that acetaldehyde can depress the conversion of glucose into umbilical artery lipids. However, acetaldehyde in the presence of equal concentrations of ethanol does not exhibit this ability to depress conversion of glucose to lipids suggesting some cellular counter effect of these two agents.

Acetaldehyde↗
PubMed1980

Effects of acetaldehyde on the membrane resistance in the smooth muscle of the guinea-pig taenia caecum.

The action of acetaldehyde on the membrane resistance of the guinea-pig taenia caecum was investigated with a double sucrose-gap method in different ionic environments. Application of acetaldehyde (10--20 mM) produced hyperpolarization, block of spike discharge and reduction of the membrane resistance. The reduction of the membrane resistance by acetaldehyde was potentiated by increasing the external K+ concentration and by replacement of Cl- with NO3-; it was reduced by lowering the external K+ concentration and by replacement of Cl- with benzenesulfonate. Replacement of NaCl with Tris-Cl, sucrose, or LiCl had no appreciable effect on the action of acetaldehyde on the membrane resistance. It therefore seemed likely that acetaldehyde increased the membrane conductance for K+ and Cl- more than for Na+. Although this action of acetaldehyde was similar to the alpha-action of catecholamine, the decrease of the membrane resistance and hyperpolarization induced by acetaldehyde remained unchanged in the presence of phentolamine.

Acetaldehyde↗
PubMed1994

Acetaldehyde-modified epitopes in liver biopsy specimens of alcoholic and nonalcoholic patients: localization and association with progression of liver fibrosis.

Acetaldehyde, the first product of ethanol oxidation, has been shown to stimulate collagen gene expression and to form protein-acetaldehyde adducts. Because little is known about these adducts in human liver tissue, we assessed, with an immunohistochemical procedure, the presence and location of acetaldehyde-protein adducts in liver biopsy specimens of alcoholic patients. In addition, we correlated the presence of adducts with the progression or subsequent occurrence of liver fibrosis. The group included 106 patients with high alcohol consumption (> 90 gm ethanol/day for the last 5 yr), 10 nonalcoholic patients with normal livers and 23 patients with other liver diseases. Sixty-four of the 106 alcoholic patients had a second liver biopsy, whose specimen was used to assess the progression of liver fibrosis. Polyclonal antibodies were produced against homologous low-density lipoprotein purified from rabbit serum and modified in vitro in the presence of acetaldehyde. Protein-acetaldehyde adducts could be detected by immunohistochemistry in biopsy specimens of 90 alcoholic patients (85%), in none of the 10 nonalcoholic patients with normal livers and in 65% of the patients with nonalcoholic liver disease. Acetaldehyde-modified epitopes were detected in the intracellular and extracellular compartment. Intracellular protein-acetaldehyde adducts were localized in the cytoplasm of hepatocytes with a more intense staining in zone 3. No correlation existed between the intensity of intracellular staining and the histologically assessed severity of liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde↗
PubMed1994

Influence of acetaldehyde on airway resistance and plasma exudation in the guinea-pig.

In anaesthetized ventilated guinea-pig, acetaldehyde (CAS 75-07-0) (40-80 mg/kg i.v.) elicits a dose-dependent increase in intratracheal pressure accompanied by an increase in circulating histamine. When acetaldehyde is injected repeatedly at 15 min intervals in capsaicin-desensitized animals, it already loses its activity at the second administration (50% reduction; p < 0.01); this does not happen in control animals. This phenomenon is even more marked when acetaldehyde is given at the dose of 80 mg/kg i.v., since at the third injection both the bronchoconstriction and the increase in blood histamine are almost completely reduced to baseline values. The increase in intratracheal pressure caused by acetaldehyde (20, 40, 80 mg/kg i.v.) is associated with a dose related increase in microvascular permeability and leakage of protein-bound Evans blue in lower tracheal tissue. This event and the bronchoconstrictor response caused by acetaldehyde (40 mg/kg i.v.) are 87% and 35% inhibited, respectively, (p < 0.01) in tachykinin-depleated animals. On the contrary, thiorphan (2 mg/kg i.v.) remarkably potentiates both the rise in intratracheal pressure (110%; p < 0.01) and Evans blue extravasation (215%; p < 0.01) induced by acetaldehyde (20 mg/kg i.v.) in normal guinea-pigs. Furthermore, treatment with CP-96,345, a selective tachykinin NK1-receptor antagonist, only prevents plasma extravasation in lower tracheal tissue (82% inhibition; p < 0.01) without affecting the bronchoconstriction caused by acetaldehyde (40 mg/kg i.v.).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde↗
PubMed1995

Effects of acetaldehyde on nuclear protein binding to the nuclear factor I consensus sequence in the alpha 2(I) collagen promoter.

Acetaldehyde has been shown to increase collagen production in cultured rat myofibroblastlike cells and to activate the mouse alpha 2(I) collagen promoter in transfected NIH 3T3 cells. Nuclear factor I (NF-I), a CCAAT binding transcription factor, is known to bind and activate the alpha 1(I) and alpha 2(I) collagen genes. Activation of the alpha 2(I) collagen promoter was not observed when the NF-I binding site of the promoter was deleted. In this study, we determined if acetaldehyde influences the binding of NF-I to the alpha 2(I) collagen promoter. Nuclear proteins extracted from NIH 3T3 cells, or myofibroblastlike cells, 36 hours after the addition of acetaldehyde (200 mumol/L) in serum-free media showed increased binding to the consensus sequence of the NF-I binding site by DNase I protection analysis and by electrophoretic mobility shift assay (EMSA) as compared with control nuclear extracts that were not exposed to acetaldehyde. Furthermore, nuclear proteins extracted from myofibroblastlike cells that had been previously exposed to acetaldehyde had a marked increase in NF-I protein, as shown by Western blot with NF-I antibodies. Antisera to NF-I resulted in a slow migrating DNA-protein-antibody complex (supershift) on EMSA. However, the NF-I antibody did not supershift all the DNA-protein complexes, and the supershift band was not increased with nuclear proteins from acetaldehyde-treated cells despite the increased binding of these nuclear protein preparations to the NF-I oligo. Therefore, nuclear proteins, in addition to NF-I, bind to the NF-I consensus sequence and may have their binding altered by acetaldehyde.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1996

Effect of acetaldehyde on oxidoreductases in tissues of rats at different ages.

The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver, brain, kidney, and muscle of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [ICDH (NAD/NADP)], succinate [SDH], malate [MDH], glutamate [GDH] and glucose-6-Phosphate [G-6-PDH] dehydrogenases were significantly increased as a function of age. However, acetaldehyde treatment significantly inhibited oxidoreductases in the tissue of 21, 90 and 180 day old rats. Liver enzymes of young (21 days) rats exhibited greater sensitivity to acetaldehyde toxicity. Similar inhibition of oxidoreductases in brain and kidney of adult (180 days) rats treated with acetaldehyde was observed. LDH and GDH as compared to other enzymes studied showed higher susceptibility to acetaldehyde toxicity. The differential sensitivity of tissues and inhibition of oxidoreductases by acetaldehyde as a function of age could be attributed to hypoxic conditions, energy crisis, and mitochondrial structural changes. The results suggest that acetaldehyde affects oxidation of glucose via HMP shunt pathway, glycolytic pathways and Krebs cycle resulting in the impairment of carbohydrate metabolism.

Acetaldehyde↗
PubMed1997

Effects of acetaldehyde on brush border enzyme activities in human colon adenocarcinoma cell line Caco-2.

The treatment of Caco-2 cells, a human colon adenocarcinoma cell line that closely resembles normal human small intestinal epithelial cells, with acetaldehyde resulted in significantly decreased activities of brush border enzymes sucrase, maltase, lactase, and gamma-glutamyltransferase; alkaline phosphatase activity was not affected. In the case of sucrase and maltase, the activities were also decreased by a combination of acetaldehyde and ethanol, although ethanol alone markedly increased them. The possibility that intraintestinal acetaldehyde, formed by intestinal microbes, might play a role in some small intestinal enzyme deficiencies observed earlier in alcoholics should therefore be considered. The mechanism by which acetaldehyde alters these enzyme activities remains unclear. The observation that acetaldehyde also disturbed cell polarization, an initial step in the process of differentiation in Caco-2 cells, indicates that acetaldehyde might decrease these enzyme activities by interfering with cell differentiation. Because ethanol and acetaldehyde metabolizing enzymes have not been previously studied from Caco-2 cells, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities were also measured from these cells, and their ALDH isoenzyme pattern was characterized. Like many cancerous cell lines, Caco-2 cells were found to express no ADH. They, however, possessed ALDH activity that was comparable with normal colonic mucosal activity and also expressed the same ALDH classes (ALDHs 1 to 3) than normal human colonic mucosa.

Acetaldehyde↗
PubMed1982

Ethylene, Ethane, Acetaldehyde, and Ethanol Production By Plants under Stress.

Red pine (Pinus resinosa Ait.) and paper birch (Betula papyrifera Marsh.) seedlings exposed to sulfur dioxide produced acetaldehyde and ethanol, and exhibited increased production of ethylene and ethane. Gas chromatographic measurement of head space gas from incubation tubes containing leaves or seedlings was a simple method of simultaneously measuring all four compounds. Increased ethylene production had two phases, a moderate increase from the beginning of the stress period and a large increase just prior to appearance of leaf lesions. Ethane production in SO(2)-stressed plants did not increase until lesions appeared. Acetaldehyde and ethanol production began within 6 hours at 0.3 microliter per liter SO(2) and 24 hours at 0.1 microliter per liter SO(2) and continued throughout a 6-day fumigation. Production of acetaldehyde and ethanol continued when plants were removed to clean air for up to 2 days. A higher concentration of SO(2) (0.5 microliter per liter) induced acetaldehyde and ethanol production within 2 hours of the start of fumigation of birch and pine seedlings. A number of other stresses, including water deficit, freezing, and ozone exposure induced production of acetaldehyde and ethanol. Production of these compounds was not due to hypoxia, as the O(2) partial pressure in the incubation vessels did not decline. Increasing the O(2) partial pressure to 300 millimeters Hg did not affect production of these compounds. Production of ethylene, acetaldehyde, and ethanol declined when more than 80% of the leaf area became necrotic, while ethane production was linearly related to the percentage of necrosis. A number of woody and herbaceous plant species produced acetaldehyde and ethanol in response to freezing stress, while others did not. Measurement of these four compounds simultaneously in the gas phase may be a valuable method for monitoring plant stress, particularly air pollution stress.

Journal Article↗