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PubMed2004

Transcriptional analysis of spo0A overexpression in Clostridium acetobutylicum and its effect on the cell's response to butanol stress.

Spo0A is the regulator of stationary-phase events and is required for transcription of solvent formation genes in Clostridium acetobutylicum. In order to elucidate the role of spo0A in differentiation, we performed transcriptional analysis of 824(pMSPOA) (a spo0A-overexpressing C. acetobutylicum strain with enhanced sporulation) against a plasmid control strain. DNA microarray data were contrasted to data from a spo0A knockout strain (SKO1) that neither sporulates nor produces solvents. Transcripts of fatty acid metabolism genes, motility and chemotaxis genes, heat shock protein genes, and genes encoding the Fts family of cell division proteins were differentially expressed in the two strains, suggesting that these genes play roles in sporulation and the solvent stress response. 824(pMSPOA) alone showed significant downregulation of many glycolytic genes in stationary phase, which is consistent with metabolic flux analysis data. Surprisingly, spo0A overexpression resulted in only nominal transcriptional changes of regulatory genes (abrB and sigF) whose expression was significantly altered in SKO1. Overexpression of spo0A imparted increased tolerance and prolonged metabolism in response to butanol stress. While most of the differentially expressed genes appear to be part of a general stress response (similar to patterns in two plasmid control strains and a groESL-overexpressing strain), several genes were expressed at higher levels at early time points after butanol challenge only in 824(pMSPOA). Most of these genes were related to butyryl coenzyme A and butyrate formation and/or assimilation, but they also included the cell division gene ftsX, the gyrase subunit-encoding genes gyrB and gyrA, DNA synthesis and repair genes, and fatty acid synthesis genes, all of which might play a role in the immediate butanol stress response, and thus in enhanced butanol tolerance.

Bacterial Proteins↗
PubMed2004

Transcriptional analysis of butanol stress and tolerance in Clostridium acetobutylicum.

The effects of challenges with low (0.25%, vol/vol) and high (0.75%) concentrations of butanol on the growth, glucose metabolism, product formation, and transcriptional program of the solvent-tolerant Clostridium acetobutylicum strain 824(pGROE1) and the plasmid control strain 824(pSOS95del) were used to study solvent tolerance and stress response. Strain 824(pGROE1) was generated by groESL overexpression. The growth of 824(pGROE1) was less inhibited than that of 824(pSOS95del), and 824(pGROE1) was able to metabolize glucose over the entire course of the culture (60 h postchallenge) while glucose metabolism in 824(pSOS95del) lasted 24 h. A comparison of their respective DNA array-based transcriptional profiles identified genes with similar expression patterns (these genes are likely to be part of a general butanol stress response) and genes with opposite expression patterns (these genes are likely to be associated with increased tolerance to butanol). Both strains exhibited a butanol dose-dependent increase in expression of all major stress protein genes, including groES, dnaKJ, hsp18, and hsp90; all major solvent formation genes, including aad, ctfA and -B, adc, and bdhA and -B (an unexpected and counterintuitive finding); the butyrate formation genes (ptb and buk); the butyryl coenzyme A biosynthesis operon genes; fructose bisphosphate aldolase; and a gene with homology to Bacillus subtilis kinA. A dose-dependent decrease in expression was observed for the genes of the major fatty acid synthesis operon (also an unexpected and counterintuitive finding), several glycolytic genes, and a few sporulation genes. Genes with opposite expression kinetics included rlpA, artP, and a gene encoding a hemin permease. Taken together, these data suggest that stress, even when it derives from the solvent product itself, triggers the induction of the solvent formation genes.

Bacterial Proteins↗
PubMed2006

Butanol ingestion in an airport hangar.

1-Butanol is a colourless organic solvent with a rancid sweet odour. 1-Butanol ingestion may result in vomiting, abdominal pain, headache, drowsiness and unconsciousness. We present a 47-year-old male with no previous medical history, who was found comatose and soiled after having vomited while unconscious. On arrival, he had a Glasgow coma scale of 3, tachycardia, hypotension, shallow tachypnoic breathing, hypotonic muscles, absent myotatic reflexes and aromatic odour. The patient was intubated and treated with oxygen, dopamine and volume replacement therapy. Gastric lavage was performed and activated charcoal was given. His initial laboratory test revealed hypokaliemia, renal failure, acidosis with elevated lactate and hypercapnic respiratory insufficiency. Twelve hours after admission, the patient started to respond to a painful stimulus and 4 h later he was conscious. He was extubated 23 h after admission. All pathological laboratory results gradually returned within normal limits. The subsequent toxicological examination of gastric content and urine sample by gas chromatography revealed 1-butanol. On awakening, he confirmed ingestion of a solvent stored in an airport hangar. In conclusion, we describe a patient who ingested - a posteriori with suicidal intention - an unknown dose of 1-butanol. Symptoms were headache, vomiting, abdominal pain, coma, muscular hypotonus, hypotension, respiratory insufficiency and mixed acidosis. The patient totally recovered after supportive therapy over 30 h. In future cases, intravenous administration of ethanol or even hemodialysis can be considered analogous to the treatment of methanol and ethylene glycol poisoning.

1-Butanol↗
PubMed2005

Utilization of excess sludge by acetone-butanol-ethanol fermentation employing Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564).

Clostridium saccharoperbutylacetonicum N1-4 could not grow or produce butanol in excess sludge medium. However, adding glucose to the excess sludge medium resulted in a specific growth rate and butanol productivity of 0.29 h(-1) and 0.55 g/l/h, respectively, and the final butanol production reached 9.3 g/l. Since the content of suspended solids in medium reduced to less than 50% of the initial content during acetone-butanol-ethanol (ABE) fermentation, the sludge was quantitatively decreased by this fermentation employing this strain.

Acetone↗
PubMed2004

Continuous production of butanol by Clostridium acetobutylicum immobilized in a fibrous bed bioreactor.

We explored the influence of dilution rate and pH in continuous cultures of Clostridium acetobutylicum. A 200-mL fibrous bed bioreactor was used to produce high cell density and butyrate concentrations at pH 5.4 and 35degreesC. By feeding glucose and butyrate as a cosubstrate, the fermentation was maintained in the solventogenesis phase, and the optimal butanol productivity of 4.6 g/(L h) and a yield of 0.42 g/g were obtained at a dilution rate of 0.9 h-1 and pH 4.3. Compared to the conventional acetone-butanol-ethanol fermentation, the new fermentation process greatly improved butanol yield, making butanol production from corn an attractive alternative to ethanol fermentation.

Acetone↗
PubMed2002

Effect of butanolic fraction of Desmodium adscendens on the anococcygeus of the rat.

The chemical composition of plants can vary according to factors such as soil and time of collection. Desmodium adscendens (Sw.) D.C. var. adscendens (Papillionaceae) is a plant employed in the treatment of asthma in Ghana, Africa. Studies have shown that butanolic extract inhibits contraction of the ileum and trachea in guinea pigs. In Mato Grosso, this plant is used only in the treatment of ovarian inflammation. The objective of this work was to verify if the plant found in Mato Grosso also relaxes smooth muscle and to understand better its action. The cumulative application of the butanolic fraction relaxed the contraction maintained in the isolated anococcygeus of a rat, induced by high potassium, but not that induced by phenylephrine. Relaxation was not altered by methylene blue. The butanolic fraction reduced in a concentration-dependent way the maximum response of concentration-response curve to calcium in the anococcygeus muscle. The results suggest that the butanolic fraction acts, at least partly, through the blockade of voltage-sensitive Ca+2 channels.

1-Butanol↗
PubMed1976

[The effect of n-butanol on the metabolic status of some organs of rats and the circulation of rabbits].

Rats received n-butanol i.m. in a dose of 0.1 g/kg body weight/die during 50 days. The metabolic status of some organs was examined and compared to that of rats which in control experiments had received 0.9% NaCl-colution in an equivalent volume (double blind experiments). The tissue levels of metabolites of the adenylic acid-creatine phosphate system, of glycogen, glucose and lactate exhibited no significant differences in both the groups. In the liver the tissue level of glycogen, free creatine and total creatine was significantly elevated in rats which had received n-butanol. In concious rabbits the effect of n-butanol on circulatory parameters was investigated in double blind experiments. n-butanol was without a significant effect in a dosage of 0.008 g/kg. A dosage of 0.033 g/kg and particularly of 0.1 g/kg resulted in a transitory decrease in the heart rate and the systolic and especially diastolic blood pressure.

Animals↗
PubMed2002

[The effects of n-butanol fraction of Lysimachia hemsleyana on the activities of lymphocytes in mice].

OBJECTIVE: To study the effects of n-butanol fraction from the whole plants (Lysimachia hemsleyana) on the phagocytic activities of the peritoneal macrophage, production of interleukin-2. METHODS: We extracted the components with ethanol, acetic ether, n-butanol and chloroform, then studied the n-butanol fraction on the phagocytic activities of the peritoneal macrophage, production of interleukin-2 (IL-2) from splenocytes induced by ConA in mice in vitro. RESULTS: n-Butanol fraction of an ethanol extract of air-dried herbs bilaterally regulated the IL-2 production from splenocytes induced by ConA, and enhanced the phagocytic activities of activated mouse peritoneal macrophages. CONCLUSION: The results suggest that Lysimachia hemsleyana may has an immunoregulation effect and may be an potential agent in the treatment of the inflammatory pathological process and some autoimmune diseases.

1-Butanol↗
PubMed1990

A routine, automated synthesis of oxygen-15-labeled butanol for positron tomography.

The use of labeled butanol for autoradiographic and positron tomographic measurement of cerebral blood flow has been well established using radiocarbon labels. The advantages of the short half-life of oxygen-15 (15O) in doing sequential flow studies are also recognized. An automated procedure has been developed for the routine rapid and sequential synthesis of 15O-labeled butanol in amounts and with purity suitable for use in positron tomography. Butanol can now replace 15O-labeled water, which is commonly used for routine applications. The 14N(d,n)15O reaction is used, with 8 MeV deuterons on a nitrogen target containing 0.2% oxygen. Labeled oxygen is reacted with tri-n-butyl-borane by passing the gas over an alumina support which holds the reagent. Washing with water through small C18-bonded phase silica cartridges eliminates labeled water and the majority of boron-containing impurities. Injectable labeled butanol is collected at 2.5 min after the end of bombardment. The yield is 6 mCi per microampere of saturated bombardment, measured at the end of synthesis. Injectable product up to 250 mCi can be obtained at 10-min intervals.

Butanols↗
PubMedDate not supplied

Ethanol and tertiary butanol induced microcephaly in the neonatal rat: comparison of brain growth parameters.

Neonatal rats were reared using an artificial feeding technique from postnatal day 4 through 18. On Postnatal Days 4 through 7, corresponding to the onset of the brain growth spurt, some animals were administered either ethanol or tertiary butanol in the milk formula, with the remaining animals serving as controls. The alcohol dosages were equated to each other by membrane to buffer partition coefficients. Following the 4 day alcohol exposure, all animals were given the plain milk formula until Day 18, when they were decapitated and various organ weights measured. The only significant weight differences between alcohol-exposed animals and controls were absolute brain weights and brain weight/body weight ratios, which were decreased in both alcohol groups. Biochemical analysis of the brains showed similar DNA levels for the ethanol, tertiary butanol, and control group forebrain samples. Both alcohol groups had significantly lower DNA levels than the control group for the hindbrain samples. Cholesterol levels and cholesterol/DNA ratios indicated that ethanol, but not tertiary butanol, impaired myelination and/or arborization. Total protein and protein/DNA ratios suggested that ethanol interfered with protein production and/or incorporation. The tertiary butanol animals did not show this deficit. The results imply that while exposure to either alcohol during the brain growth spurt can lead to microcephaly, the ethanol-induced alteration of myelin formation and protein production in neonatal brain tissue may be due to additional properties of ethanol.

Animals↗
PubMed1997

Effect of Temperature on the Mixed Micellar Tetradecyltrimethylammonium Bromide-Butanol System.

The TTAB-butanol system has been studied over a temperature range of 15 to 35 degreesC and at butanol concentrations up to 0.3 mol/kg. The CMC vs temperature curves have a smooth minimum whose location is not markedly influenced by alcohol presence. The molar fraction of butanol in the micelles and the entropy of micellization have been calculated using a theoretical treatment of critical micelle concentration data based on excess thermodynamic quantities. The heat capacity of micellization has been obtained and compared with results predicted by a recent thermodynamical theory which describes a universal behavior exhibited by ionic surfactants. Both the entropy and the enthalpy of micellization increase with alcohol concentration. The butanol molar fraction in micelles enables us to estimate the standard free energy of solubilization, which is found to decrease with temperature. It is important to emphasize the chance of predicting the value of these interesting thermodynamic quantities without the need for measuring them. The degree of micelle ionization has also been evaluated using two different methods, and no significant differences have been observed. Copyright 1997 Academic Press.

Journal Article↗
PubMed1998

Miscibility of Butanol and Cationic Surfactant in the Adsorbed Film and Micelle.

Mixed adsorbed films and micelles were investigated by measuring surface tension of the aqueous solutions for the following four mixtures: the n-butanol (NBA)-dodecylammonium chloride (DAC), t-butanol (TBA)-DAC, NBA-dodecyltrimethylammonium chloride (DTAC), and TBA-DTAC. Experimental results were analyzed thermodynamically. Phase diagrams of adsorption and micelle formation and that exhibiting the composition relation of micelle and adsorbed film at CMC were compared among the four systems. Excess Gibbs energy in the adsorbed film gH,E and activity coefficient in the micelle fM2+/- were calculated from the phase diagrams to estimate the miscibility of the butanol and cationic surfactant quantitatively. By comparing the results of the pairs of NBA-DAC and TBA-DAC systems with those of the NBA-DTAC and TBA-DTAC systems, it was shown that the substitution of the polar head group from ammonium to trimethylammonium changes the gH,E value from positive to negative and increases fM2+/-. Furthermore, by comparing the results of the pairs of NBA-DAC and NBA-DTAC systems with those of the TBA-DAC and TBA-DTAC systems, it was shown that the bulky hydrophobic group weakens the molecular interaction between the butanol and the cationic surfactant in the adsorbed film. Copyright 1998 Academic Press.

Journal Article↗
PubMed2005

Rapid identification of target genes for 3-methyl-1-butanol production in Saccharomyces cerevisiae.

Extracellular conditions determine the taste of fermented foods by affecting metabolite formation by the micro-organisms involved. To identify targets for improvement of metabolite formation in food fermentation processes, automated high-throughput screening and cDNA microarray approaches were applied. Saccharomyces cerevisiae was cultivated in 96-well microtiter plates, and the effects of salt concentration and pH on the growth and synthesis of the fusel alcohol-flavoured substance, 3-methyl-1-butanol, was evaluated. Optimal fermentation conditions for 3-methyl-1-butanol concentration were found at pH 3.0 and 0% NaCl. To identify genes encoding enzymes with major influence on product formation, a genome-wide gene expression analysis was carried out with S. cerevisiae cells grown at pH 3.0 (optimal for 3-methyl-1-butanol formation) and pH 5.0 (yeast cultivated under standard conditions). A subset of 747 genes was significantly induced or repressed when the pH was changed from pH 5.0 to 3.0. Expression of seven genes related to the 3-methyl-1-butanol pathway, i.e. LAT1, PDX1, THI3, ALD4, ILV3, ILV5 and LEU4, strongly changed in response to this switch in pH of the growth medium. In addition, genes involved in NAD metabolism, i.e. BNA2, BNA3, BNA4 and BNA6, or those involved in the TCA cycle and glutamate metabolism, i.e. MEU1, CIT1, CIT2, KDG1 and KDG2, displayed significant changes in expression. The results indicate that this is a rapid and valuable approach for identification of interesting target genes for improvement of yeast strains used in industrial processes.

Culture Media↗
PubMed1985

Acetone-butanol fermentation and its variants.

Recent intensive research on the acetone-butanol-ethanol and the isopropanol-butanol-ethanol fermentation has increased the basic understanding of these processes substantially. Metabolic investigations on Clostridium acetobutylicum, and Clostridium beijerinkii show that enzyme activities necessary for solvent production are induced only in solvent-producing cells. Although produced, or added, acetic and butyric acid have significant effects on the metabolic activities, the transition from acid to solvent production cannot as yet be fully explained. Based on studies in continuous cultures, the kinetics of product formation can be described. Knowledge of the mechanism of butanol toxicity is accumulating but no dramatic increase in butanol tolerance has so far been obtained. Successful results, approaching the limitations determined by biological and technological possibilities, have been obtained in batch and continuous cultures, and in continuous processes based on immobilized cells. Continuous processes are superior to batch cultures in respect of their productivity.

Journal Article↗
PubMed2006

Enzymatic production of biodiesel from cotton seed oil using t-butanol as a solvent.

The enzymatic production of biodiesel by methanolysis of cottonseed oil was studied using immobilized Candida antarctica lipase as catalyst in t-butanol solvent. Methyl ester production and triacylglycerol disappearance were followed by HPLC chromatography. It was found, using a batch system, that enzyme inhibition caused by undissolved methanol was eliminated by adding t-butanol to the reaction medium, which also gave a noticeable increase of reaction rate and ester yield. The effect of t-butanol, methanol concentration and temperature on this system was determined. A methanolysis yield of 97% was observed after 24h at 50 degrees C with a reaction mixture containing 32.5% t-butanol, 13.5% methanol, 54% oil and 0.017 g enzyme (g oil)(-1). With the same mixture, a 95% ester yield was obtained using a one step fixed bed continuous reactor with a flow rate of 9.6 mlh(-1) (g enzyme)(-1). Experiments with the continuous reactor over 500 h did not show any appreciable decrease in ester yields.

Catalysis↗
PubMed2001

Acute and chronic exposure to ammonia and olfactory acuity for n-butanol in the pig.

An associative learning method (using a food reward) was developed to measure pigs' olfactory acuity for n-butanol, a standard odourant in human olfactometry. The pig could press two operant paddles but it only received a food reward when it pressed the one over which n-butanol was released. Once each pig had reached a training criterion (10 consecutive roots on the correct paddle on each of two consecutive sessions) this method was used to assess the impact of acute and chronic exposure to an atmosphere containing approximately 40 parts per million (ppm) ammonia gas, compared to fresh air, on its ability to perceive different concentrations of n-butanol. These were presented using a staircase pattern, i.e. if the pig gained or failed to gain a food reward on two consecutive occasions the concentration was reduced or increased, respectively. Acute exposure for approximately 45min to about 40ppm ammonia had no effect (P>0.05) on the lowest detected concentration (LDC) of n-butanol in six pigs. The geometric mean LDC was 1.23 parts per trillion (ppt) in approximately 40ppm ammonia and 2.09ppt in fresh air. The LDC of three pigs increased, i.e. acuity fell, from 5.1 to 175.5ppt over 24 days of exposure to congruent with40ppm ammonia. Ammonia had no effect on one of the other pigs and the high variability in the LDC for the remaining two pigs produced no meaningful assessment of its impact. Subsequent removal to fresh air for a further 24 days led to partial recovery of acuity in one of the three pigs that had shown evidence of olfactory impairment but not in the other two. Collectively our findings suggest that chronic, but not acute, exposure to congruent with40ppm ammonia can interfere with olfactory perception in some pigs (50% of our sample) and that this loss of acuity is not necessarily reversible.

Journal Article↗
PubMed2005

Evaporation of water through butanol films at the surface of supercooled sulfuric acid.

The evaporation of water was monitored from 60, 64, and 68 wt % D(2)SO(4) at 213 K containing 0-0.18 M 1-butanol. Measurements were performed in vacuum using a mass spectrometer to record the velocities and relative fluxes of the desorbing D(2)O. In addition, the surface activity of butanol in the acid was characterized by hyperthermal argon atom scattering in conjunction with surface tension and butanol evaporation measurements. The segregated butyl species reach surface concentrations of approximately 4 x 10(14) cm(-2) (approximately 80% surface coverage) at 0.18 M bulk concentration. We find that the butyl films do not impede the evaporation of D(2)O from the acid to within the 5% uncertainty of the measurements. This result implies that small, soluble surfactants such as butanol form porous films that will not alter the growth or shrinkage of supercooled sulfuric acid droplets in the atmosphere.

Journal Article↗
PubMed2005

A new force field for atomistic simulations of aqueous tertiary butanol solutions.

We present a new tert-butanol force field parametrized to reproduce the mixture thermodynamics of tert-butanol/water over a wide range of solution compositions at room temperature and atmospheric pressure. The experimental Kirkwood-Buff integrals, which quantify preferential solvation of solution components by the same species or by the other components, were used as target values to be reproduced. Water was modeled using the simple point charge model. In the range of alcohol mole fractions between 0.02 and 0.98, our optimized model satisfactorily reproduces alcohol-alcohol, water-water, and alcohol-water aggregation behavior. As a consequence, the solution activity derivatives are reproduced as well. A comparison has been made with solution activities obtained by free energy calculations (i.e., thermodynamic integration). It clearly shows that the Kirkwood-Buff based approach performs superior in predicting solution activities of liquid mixtures. The new tert-butanol model has been used to examine the solution structure and hydrophobic interactions in aqueous tert-butanol at the various mixture compositions. A comparison is made with structural data obtained by neutron diffraction.

Journal Article↗