Low Concentrations Of Acetic Acid Research Articles

Effects of Isolated and Commercial Lactic Acid Bacteria on the Silage Quality, Digestibility, Voluntary Intake and Ruminal Fluid Characteristics

Silage is a major component of cattle rations, so the improvement of silage quality by the inoculation of lactic acid bacteria is of great interest. In this study, commercially distributed Lactobacillus plantram and Lactobacillus rhamnousas NGRI 0110 were used for ensilaging of guinea grass. The four treatments used were a control silage, a silage with cellulase addition, a silage with cellulose+L. plantram addition, and a silage with cellulose + NGRI 0110 addition. Silage quality, voluntary intake, nutrient digestibility, and the characteristics of ruminal fluid of wethers were investigated. Silage to which lactic acid bacteria were added showed low pH and acetic acid concentration and the highest lactic acid content. Dry matter and organic matter digestibility were significantly (p<0.05) increased by cellulase addition and significantly (p<0.05) higher values were observed in L. plantram- and NGRI 0110-added silage. Voluntary intake of NGRI 0110-added silage was the highest and that of control silage was the lowest. We concluded that the observed ability of NGRI 0110 to tolerate low pH and to continue lactic acid fermentation in high lactic acid concentration had also occurred in actual ensilaging. The results indicate that the addition of lactic acid bacteria might improve silage quality and increase digestibility and voluntary intake. The potential for improvement by NGRI 0110 was higher than that to be gained by the use of commercially available lactic acid bacteria. (Asian-Aust. J. Anim. Sci. 2006. Vol 19, No. 3 : 386-389)

Effects of Inhibitory Environmental Factors on Growth ofOenococcus oeniCCSYU2068 for Malolactic Fermentation of Cider Production

The effects of several inhibitory factors (sulfur dioxide, pH and ethanol) on the growth of lactic acid bacteria and the subsequent malolactic fermentation (MLF) were studied by inoculation of different culture strains of Oenococcus oeni, the major lactic acid bacteria (LAB) in cider production. After comparing their organoleptic properties, three strains of Oenococcus oeni were selected from indigenous and commercial sources and their inhibitory effects on cell growth and MLF examined. The malolactic bacteria expressed variations in tolerance to the environmental conditions of pH, sulfur and ethanol concentration. Isolated from an indigenous cider production facility, O. oeni L4 had a better capacity with constant growth even when the concentration of SO 2 was 50 ppm, ethanol 10% (v/v) and pH 3.0. O. oeni L4 showed better properties for metabolizing the major acids: malic, lactic and acetic acid. The decomposition mean rate of malic acid was as high as 228.52 mg/L per day with a low acetic acid concentration of 101.78 mg/L under the stress conditions of cider production.

The effect of acetic acid, citric acid, and trisodium citrate in combination with different levels of water activity on the growth of Arcobacter butzleri in culture.

The influence of weak organic acids and trisodium citrate in combination with a high or a reduced water activity (aw) was investigated when a population of Arcobacter butzleri was exposed to a low concentration of acetic or citric acid, and trisodium citrate combined with high (0.993) and reduced (0.977) aw in culture broth at 30 degrees C. Regardless of water activity, acetic and citric acid (> 0.2%) inhibited the growth of A. butzleri with no viable cells detected after 4-5 h of incubation. Enhanced survival was found at reduced aw with addition of acetic acid. In contrast, after exposure to citric acid in combination with reduced aw inactivation was more rapid than that after being exposed to high water activity. Incorporation of trisodium citrate in combination with reduced aw (0.977) would probably not confer any extra protection. Concentrations of organic acid widely used in meat decontamination processing represent feasible tools for reducing A. butzleri contamination and hence the risk of Arcobacter infection.

Ensiled Green Tea Waste as Partial Replacement for Soybean Meal and Alfalfa Hay in Lactating Cows

The purpose of this study was to evaluate the effects of protein supplementation of green tea waste (GTW) on the performance of lactating cows. Another aim was to increase resource utilization and to eliminate any environmental negative impact from the tea waste. GTW from a beverage company was ensiled at a low pH (<4.0) and high acetic acid and lactic acid concentration, and it contained high crude protein (CP, 34.8%), total extractable tannins (TET, 9.2%) and condensed tannin (CT, 1.7%). Two experiments were conducted to investigate the palatability and performance in lactating cows fed GTW. In the palatability trial, three lactating cows were allocated to three dietary treatments in a 3×3 Latin square design. The animals were offered a total mixed ration (TMR) including GTW at rates of 0, 2.5 and 5.0% on a dry matter (DM) basis. Total DM intake was not different among the treatments. In the performance trial, four lactating cows were used in a 2×2 Latin square design with a 3 week sampling period. GTW was incorporated into TMR at a rate of 5.0% on a DM and 10.0% on a CP basis. Thus GTW replaced alfalfa hay and soybean meal at a level of 25.0% on a DM. DM and CP intake were not affected by the inclusion of GTW, whereas TET and CT intake were significantly increased (p<0.001). Milk production, milk composition and the efficiency of milk production were not altered by the GTW inclusion. Although ruminal pH and VFA, and blood urea nitrogen were not changed, ruminal NH3-N and plasma total cholesterol were relatively low in the GTW group, but not significantly different. The excretion of urinary purine derivatives and estimated MN supply were also not significantly affected by GTW treatment. It is therefore concluded that GTW can be used as a protein source without any detrimental effects on the performance of lactating cows. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 7 : 960-966)

Anaerobic oxidation of cysteine to cystine by manganese(III) in aqueous acetic acid

The anaerobic oxidation of cysteine, Cys, by Mn(III) in acetic acid solutions has been followed by use of a stopped-flow spectrophotometric method at a temperature of 20 °C. The formation and disappearance of the [Mn(OAc) 2Cys] − complex was monitored at 350 nm. The rate depends strongly on the acetic acid concentration (and hence also on pH) and led to the conclusion that more than one cysteine-containing species was involved. These mono-cysteinyl complexes are formed by the loss of two protons from the cysteine – one from the – SH and the other from either the –NH 3 + or, more likely, the –COOH which is partially protonated at the low pH values involved (0.5–2.5). The rate-determining reprotonation of the bound –COO − (or –NH 2) is then accompanied by internal electron transfer yielding Mn(II) and the cysteinyl radical, Cys•, which then dimerises to form (inactive) cystine. At high acetic acid concentrations (60–90% AcOH) the tris-acetato species, [Mn(OAc) 3], predominates together with some of the bis-complex, [Mn(OAc) 2] +, and the active species is [Mn(OAc) 2Cys] − which decomposes with a rate constant of k 2=16.8±0.9 M −1 s −1. At low acetic acid concentrations (20–30% AcOH) the mono-acetato species predominates and the reactive species is [Mn(OH)Cys] for which the rate of decomposition= k 2 ′=(1.32±0.11)×10 4 M −1 s −1. The relative values of the rate constants obtained are discussed, as is the bonding of cysteine to manganese(III).

Activities for phenol formation using Cu catalysts supported on Al2O3 in the liquid-phase oxidation of benzene in aqueous solvent with high acetic acid concentration

Abstract The liquid-phase oxidation of benzene to phenol using a Cu catalyst supported on Al2O3 was studied at 303 K in an aqueous solvent with a variety of concentrations of acetic acid. Gaseous O2 and ascorbic acid were utilized as an oxidant and a reducing reagent, respectively. An aqueous solvent with more than around 70–80 vol.% acetic acid concentration was confirmed to cause a sharp apparent decrease in the Cu leaching from a Cu catalyst (Cu/Al2O3) impregnated on Al2O3, as well as a CuO-Al2O3 catalyst prepared by a co-precipitation method reported previously, during the benzene oxidation, keeping the yield of phenol comparatively high. The apparent Cu leaching was largely inhibited in an aqueous solvent with high acetic acid concentration in comparison with a solvent of low acetic acid concentration, irrespective of the presence of benzene and/or ascorbic acid. The influences of both the Cu amount supported on the Cu/Al2O3 catalyst and the amount of ascorbic acid on the yield of phenol were investigated in the aqueous solvents with acetic acid concentrations of both 5.7 and 80 vol.%. The Cu/Al2O3 catalyst in the aqueous acetic acid solvent was deactivated in the comparatively initial stage of the oxidation of benzene. The catalytic activity of the used Cu supported catalyst for phenol formation was almost completely recovered by calcining the catalyst at 773 K. The amount of the deactivated Cu species based on a XRD peak at 2θ=23° in the used Cu/Al2O3 catalyst was found to have a correlation with the yield of phenol.

Image-guided Percutaneous Chemical and Radiofrequency Tumor Ablation in an Animal Model

To determine whether combining acetic acid instillation before radiofrequency (RF) ablation can improve local tissue electrical conductivity, RF energy deposition, intratumoral heating, and tumor necrosis in a large animal model. Multiple hypovascular canine venereal sarcomas were implanted in 11 mildly immunosuppressed dogs (25 mg/kg cyclosporin A twice daily). Tumors were incubated for 8-12 weeks to 4.2 cm +/- 0.6 in diameter. Treatment strategies included 10% and 15% acetic acid diluted in distilled water, 10% and 15% acetic acid diluted in saturated NaCl solution, 50% acetic acid, and 100% ethanol, with 6 mL of each injected alone or in combination with RF ablation (internally cooled, 1-cm tip; 12 minutes). Two additional control groups were studied in which tumors received either RF alone or distilled water injected alone. Comparisons were also made with groups treated with 36% NaCl with and without RF ablation. Resultant coagulation for these ablative strategies, along with local temperatures and RF parameters such as impedance, current, and power, were compared. Increasing coagulation was observed with increasing acetic acid concentrations (1.7 cm +/- 0.4, 2.8 cm +/- 0.6, and 3.5 cm +/- 0.3 for 10%, 15%, and 50% acetic acid alone, respectively; P <.01). The combination of RF ablation with acetic acid resulted in greater coagulation than with either therapy alone (P <.05). However, maximum heating and coagulation were observed with 10% acetic acid diluted in NaCl, with which the entire tumor (diameter, 4.5 cm +/- 0.4) was completely ablated in every case. This was equivalent to results for tumors treated with 36% NaCl combined with RF. RF with a 50% acetic acid concentration resulted in coagulation measuring only 3.7 cm +/- 0.3 (P <.01). Significantly greater RF heating (89.7 degrees C +/- 12.3 at 10 mm) was observed when the tumors were pretreated with 10% or 15% acetic acid in saturated NaCl, compared with 67.9 degrees C +/- 13.7 observed when acetic acid was diluted in water (P <.02). RF combined with ethanol produced less coagulation (2.8 cm +/- 0.3) than combinations with acetic acid because rapid and irreversible impedance increases were observed. Addition of acetic acid injections to RF ablation substantially increases tumor destruction compared with RF or injection therapy alone. However, lower acetic acid concentrations in saturated NaCl produced greater tumor coagulation, suggesting that, in this hypovascular tumor model, alterations in electrical conductivity play a more important role in increasing tumor ablation efficiency than do the additional ablative effects of acetic acid.

Interaction of soybean agglutinin with leukemic T-cells and its use for their in vitro separation from normal lymphocytes by lectin-affinity chromatography.

A procedure for separation of leukemic T-cells from normal lymphocytes, using lectin-affinity column chromatography, is described. CNBr-activated Sepharose 6MB was used as a non-mobile phase. The gel was covalently coupled with soybean agglutinin (SBA), then served as an affinity probe for fractionation of mixture of normal lymphocytes and leukemic cells. Leukemic cell lines, derived from acute lymphoblastic leukemia (Jurkat, MOLT-4, RPMI-8402), were tested. The elution of normal lymphocytes was carried out by PBS(-). The leukemic T-cells, interacting with SBA, were removed by N-acetyl-D-galactosamine or low-concentration acetic acid. The type and viability of the separated cell fractions were analyzed by flow cytometry and fluorescent microscopy, using adequate fluorescent antibodies. The interaction of leukemic T-cells with free SBA, as well as with SBA-conjugated Sepharose beads, was examined fluorimetrically and visualized by fluorescent microscopy, using FITC-SBA as a marker. The rate of cell elution on SBA-affinity column decreased in order: normal > leukemic T-cells. Both normal lymphocytes and leukemic T-cells were removed in a mixture from SBA-free Sepharose 6MB by PBS(-) and were not fractionated discretely. The leukemic T-cells specifically interacted with SBA as well as with SBA-affinity adsorbent. In contrast, the normal lymphocytes did not interact with free SBA as well as with SBA-conjugated Sepharose beads in the concentrations applied. The method potentially combines a discrete cell fractionation with manifestation of a specific target cytotoxicity of SBA against leukemic T-cells, without any influence on normal lymphocytes.

Acetic acid-derived prostaglandin-dependent colonic adaptive cytoprotection is preserved in chronic colitis: role of cyclo-oxygenase.

We recently reported the phenomenon of prostaglandin-dependent colonic adaptive cytoprotection (CAP) against acute colonic injury induced by acetic acid (AA) in the normal colon. This study investigated whether the CAP is preserved in the chronic inflamed colon. Normal rats and a chronic colitis model, induced by trinitrobenzene sulfonic acid, received an intracolonal administration (0.5 ml) of saline or AA at low concentration (1%) followed by high concentration (8%) 30 min later. The distal colon was removed 48 h after 8% AA administration, and colitis was assessed by macroscopic scoring and measurement of the myeloperoxidase (MPO) activity. Indomethacin (5 mg/kg), a nonselective cyclo-oxygenase (COX) inhibitor, or N-[2-cyclohexyloxy-4-nitrophenyl] methane-sulfonamide (NS398, 1 mg/kg), a COX type 2 selective inhibitor, was injected intraperitoneally 1 h before pretreatment with 1% AA. Intracolonal administration of 8% AA induced colonic mucosal damage (macroscopic score 10.0+/-0.9) and elevated MPO activity (2.8+/-0.2 U/g), which were significantly reduced to 3.3+/-0.8 and 1.8+/-0.2 U/g by 1% AA pretreatment, respectively. Indomethacin abolished the gross mucosal protective effect by 1% AA pretreatment in 8% AA-derived colitis in normal rats while the NS398 had no effect. Both indomethacin and NS398 reversed the MPO activity reduction induced by 1% AA pretreatment. In chronic inflamed colon 8% AA treatment resulted in an increase in the macroscopic score to 11.5+/-0.4 from 4.7+/-0.4, but not the MPO activity, which was significantly reduced to 5.7+/-0.9 by 1% AA pretreatment. This gross mucosal protective effect by 1% AA pretreatment in chronic inflamed colon was reversed by indomethacin while the NS398 had no effect. These data show that COX-1 and COX-2 derived prostaglandins induced by low concentration AA pretreatment reduce the colonic mucosal injury and the increase in the MPO activity in colitis, respectively. The protective effect of COX-1 is preserved in chronic inflamed colon. These findings support the existence of a low concentration of AA-derived prostaglandin-dependent CAP and suggest that colonic AA, which is derived from bacterial breakdown of carbohydrate and protein in the colon, plays a crucial role in the endogenous defense mechanisms.

A new method to clean industrial water from acetic acid via esterification

The valorisation of very low concentration of acetic acid (6%, w/w) was investigated by reacting with n-butanol and 2-ethyl-1-hexanol taking advantage of the different solubilities of acetic acid and acetic ester in water. The esterification of very diluted solution of acetic acid with alcohol is a reversible reaction and the conversion is greatly restricted by equilibrium limitation. Therefore, the peculiarity of the present method is to shift the reaction equilibrium towards the ester and not towards the reagents, thermodynamically favourite, because of the large amount of water. Different acid catalysts were tested in both homogeneous (sulphuric acid) and heterogeneous phase (polymeric resins and sulphated zirconia) to optimise the process efficiency.

Ag+-hPLC of conjugated linoleic acids on a silica-based stationary phase. Part II: Resolution and extrapolations

For the conjugated linoleic acids (CLAs), we present the effects upon retention of the progressive addition of acetonitrile (ACN) to hexane-based mobile phases that contain background concentrations of acetic acid (AA) of 1.5, 2.0, and 3.0% by volume. An analysis of the variation in resolution across the range of elution conditions leads to unambiguous conclusions about the optimum conditions for separation and quantitation. Lower AA concentrations (≤ 1.5%) combined with low to moderate amounts of ACN (0.005–0.03%) yield good and uniform resolution amongst the major group of cis,trans/trans,cis (c,t/t,c) isomers that are believed to contain the demonstrated, desirable biological effects. For this range of %ACN, these major isomers elute around 22 and 16 minutes, respectively, and in the latter case the isocratic analyses are completed in 24 minutes. Extrapolations of the two sections of the linear dependence of the log k ′ versus %ACN plots back to zero %ACN yield data points for each background %AA that are compared with the directly measured retention of the CLAs in the presence of only AA as the strong solvent. The upper linear sections clearly relate to total retention due to all adsorption mechanisms and the extrapolations agree with the direct measurements. The lower linear sections appear to relate to that component of retention due to interaction between the CLA π bonds and Ag+ and the extrapolation thereof to the ability of AA to overcome this adsorption. These intercepts appear to reflect the diminishing general solvent strength for elution of the CLAs due to the Ag+-π bond adsorption as %AA decreases.

Effects of tissue culture conditions during embryoid multiplication on the incidence of "mantled" flowering in clonally propagated oil palm.

New and established embryoid lines of oil palm (Elaeis guineensis Jacq.) clones, classified with regard to the expected risk of mantled flowering, were included in experiments to determine to what extent culture conditions during 48 weeks of embryoid multiplication could influence the incidence and severity of mantled flowering. Variables tested included clone risk status, duration of transfer interval, and plant growth regulator composition of the culture medium. Clones classified as high risk at the outset gave a significantly higher incidence of mantled flowering in the field than clones classified as low/medium risk, confirming that data on terminal inflorescences produced in vitro allows effective screening of material with regard to the risk of mantled flowering. The incidence of mantled flowering ranged from 0 to 100% depending on risk status of the clones, and the treatments applied. In general, a relatively long transfer interval (8 weeks) and a high auxin/cytokinin ratio resulted in the lowest incidence of mantled flowering with all types of material. Reducing the transfer interval down to 2 or 4 weeks, and/or using media with relatively high concentrations of kinetin (0.25 mg l−1), and low concentrations of naphthalene acetic acid (0 or 0.1 mg l−1), resulted in a high incidence of mantled flowering (above 30%), even with low/medium risk clones. Exclusion of plant growth regulators from the embryoid multiplication medium did not prevent some mantled flowering (12%) of new embryoid lines of low/medium risk clones following embryoid multiplication on a 4 week transfer interval, and a much higher incidence of mantling (above 90%) of lines from high risk clones.

The Effect of a Dry or Liquid Application of Lactobacillus plantarum MTD1 on the Fermentation of Alfalfa Silage

Alfalfa was wilted to 30 and 54% dry matter and was untreated or treated with Lactobacillus plantarum MTD1 applied either as a liquid or dry inoculant to determine whether form of inoculation affected silage fermentation. In silages with 30% dry matter, both forms of inoculation resulted in silages with more lactic acid and a lower pH than in untreated silage after 2 d of ensiling. In addition, both forms of inoculation resulted in silages with lower concentrations of acetic acid between 8 and 45 d of ensiling than in untreated silage. The ammonia-N content was also lower in silages that had been treated with both forms of inoculation during the early and intermediate stages of ensiling, but not after 45 d of ensiling. In silages containing 54% dry matter, dry and liquid inoculation produced a more rapid decrease in pH from d 4 to 14 when compared with untreated silage, but the effect was greater when the inoculant was applied in water. In contrast to findings from 30% silages, the inoculated silages with 54% dry matter had lower concentrations of ammonia-N than untreated silage from d 8 to 45, and both forms of inoculation were equally effective. The results of this study agree with previous research that shows that microbial inoculation can improve the fermentation of alfalfa silage. However, this report shows that a microbial inoculant was more effective when applied in a liquid- rather than a dry-form to alfalfa with a high DM content.

Dual effect of cAMP on the writhing response in mice

The intraperitoneal injection of agents that increase the intracellular level of cyclic AMP (cAMP), reduced significantly the number of writhes induced by acetic acid and zymosan in mice. However, dibutyryl cyclic AMP (Db-cAMP) induced a dual response: (a) low doses caused antinociception, and (b) a high dose potentiated the nociceptive effect of a low concentration of acetic acid. High doses of Db-cAMP also reversed the antinociceptive effect of dexamethasone and the depletion of resident peritoneal cells. We also demonstrated that a low dose of Db-cAMP, forskolin or dexamethasone inhibited the production of tumor necrosis factor-α and interleukin-1β by macrophages stimulated by zymosan. In conclusion, this study suggests that cAMP has a dual effect in the writhing model: an antinociceptive effect due to its modulatory action on resident peritoneal cells, thus, reducing the synthesis of mediators involved in the nociceptive response, and a nociceptive effect by directly sensitizing the nociceptive neuron.

Chitosan modified poly(glycidyl methacrylate–butyl acrylate) copolymer grafted bovine pericardial tissue—anticalcification properties

Calcification is the main cause of failure of glutaraldehyde crosslinked pericardial tissue used as heart valve substitutes. In our earlier work, we have shown that the grafting of glutaraldehyde crosslinked pericardial tissue with poly[glycidylmethacrylate(GMA)–butyl acrylate(BA)] copolymer with monomer ratio of 15:7.2 resulted in 50% reduction in calcification. In the present investigation, an attempt was made to eliminate calcification of the polymer grafted glutaraldehyde crosslinked pericardial tissue by coupling with low molecular weight chitosan. Low molecular weight chitosan was prepared to improve its solubility in water containing lower concentration of acetic acid and ensure easy diffusion into the tissue fiber matrix. The effect of treatment with the prepared chitosan on the anticalcification properties of poly(GMA–BA) copolymer grafted pericardial tissue was studied. It was found that chitosan post treatment of copolymer grafted glutaraldehyde crosslinked pericardial tissue was able to reduce the susceptibility of the glutaraldehyde crosslinked pericardial tissue to negligible levels after 30 days of implantation in rat subcutaneous models.

Heat-induced conformational transition of cytochrome c observed by temperature gradient gel electrophoresis at acidic pH.

Temperature-gradient gel electrophoresis (TGGE) has been used to study the thermal unfolding of ferricytochrome c in low and high concentrations of acetic acid. It has been observed that the mobility of cytochrome c is a linear function of temperature when the system is characterized by a homogeneous population of conformation-state, single molecular species. Within the transition temperature range, the mobility clearly displays the characteristic sigmoidal shape describing the transitions of protein unfolding. The data obtained by TGGE were used to estimate the apparent thermodynamic parameters (enthalpy change deltaHvh and transition temperature Tm), associated with the transition of unfolding. The accuracy of the apparent thermodynamic parameters obtained by this method agrees within error limits with the values obtained by direct calorimetric measurements using differential scanning calorimetry (DSC).

Effects of ethanol, acetaldehyde, and acetic acid on histamine secretion in guinea pig lung mast cells

We studied the direct effects of ethanol and its metabolites on the guinea pig lung mast cell, and the alterations caused in the histamine release induced by different stimuli. Guinea pig lungs cells dispersed by collagenase were used throughout. High concentrations of ethanol (100 mg/ml), acetaldehyde (0.3–3 mg/ml) and acetic acid (3 mg/ml) induced histamine release that was not inhibited by sodium cyanide (0.3 mM). Lower concentration of ethanol (10 mg/ml) and acetic acid (0.3 mg/ml), but not acetaldehyde, inhibited the histamine release induced by antigen and ionophore A23187. The histamine release induced by phorbol 12-miristate 13-acetate (1 μM) was also inhibited by ethanol (10 mg/ml). Changes in the levels of calcium, glucose and phosphatidic acid did not influence the effect of ethanol. We conclude that high doses of ethanol, acetaldehyde, and acetic acid cause a cytotoxic histamine release by independent mechanisms. Low concentrations of acetic acid inhibit the histamine release by pH reduction. Ethanol acts by a generalized effect that is independent of calcium and glucose suggesting a nonspecific effect that, nevertheless, is not cytotoxic since it can be reversed by washing the cells.

Trans-dominant mutations in the GPR1 gene cause high sensitivity to acetic acid and ethanol in the yeast Yarrowia lipolytica.

Acetate non-utilizing strains harbouring trans-dominant mutations in the GPR1 gene (GPR1(d)) of the dimorphic yeast Yarrowia lipolytica have been selected and characterized. These mutants are highly sensitive to low concentrations of acetic acid and ethanol, even in presence of glucose. The toxic effect of acetic acid is pH-dependent and has the strongest effect at low pH. In contrast, the action of ethanol is pH-independent. One GPR1(d) mutant has been detected that was highly sensitive to acetic acid but could still grow on ethanol, which indicates putative differences in the function of the GPR1 gene product in the sensitivity to acetic acid and ethanol. The GPR1(d) mutants exhibit a complex pleiotropic phenotype. The mutations cause changed colony morphology as well as dimorphism of cells, and induce early cell death during growth on glucose, even without the presence of dicarbon compounds. Composition of intracellular membranes, as well as morphology of vacuole and mitochondria, were strongly changed. Back-crosses with wild-type strains and analysis of recombinant strains have shown that the expression of the pleiotropic phenotype depends on the site of mutation in the GPR1 gene, as well as on the genetic background of the strain harbouring the responsive mutation. Our data suggest that Gpr1p is involved in a general response of cells to the toxic action of dicarbon compounds like acetic acid and ethanol.

Inhibitory effect of acetic acid on growth of hyperthermophilic archaeon Pyrococcus furiosus

The growth inhibition of Pyrococcus furiosus by acetic acid was stronger than that by hydrogen and could be described by a non-competitive inhibition model in which the inhibition constants of undissociated acetic acid, K p and n, were estimated to be 0.69 mM (25 mM total acetic acid at pH 6.5; pKa=4.96; 98°C) and 1.0, respectively. In order to reduce the acetic acid inhibition, repeated-batch culturing was performed using a filtration module. This yielded 0.49 g of dry cells l −1 after growth for 12 h after inoculation. It became impossible, however, to continue repeated-batch culturing manually because the time intervals for medium replacement became too short. In order to automatically maintain a low concentration of acetic acid, a perfusion culture was carried out in which medium feeding coupled to a pH-auxostat was performed. In this perfusion culture, it was possible to maintain the acetic acid concentration below 7.6 mM during exponential growth of P. furiosus, resulting in 1.8 g of dry cells l −1 at 15 h after inoculation.

髄液中神経伝達物質，アミノ酸およびフリーラジカル関連物質の脳血管障害患者における変化

Acetylcholinesterase (AChE), choline, monoamine and its metabolite, amino acid and superoxide dismutase (SOD) levels were measured in cerebrospinal fluid (CSF) in patients with cerebrovascular diseases. Patients were classified into the following four groups; controls: normal subjects without neurological disease, group A: cerebral hemorrhage, group B: cerebral infarction, group C: patients with mental impairment, including those in groups A and B, and a low score on Hasegawa's Dementia Rating Scale. CSF AChE level of groups A, B and C was decreased significantly, while choline concentration from patients showed a increase compared with that of control cases. CSF alanine concentration showed a tendency to increase, while glycine and glutamate tended to decrease. CSF epinephrine, norepinephrine or 3-methoxy-4-hydroxyphenylethylen glycol concentrations of groups A, B and C did not exhibit a significant difference from that in control cases. Some cases with cerebrovascular diseases showed low concentrations of both CSF 5-hydroxyindole acetic acid and homovanillic acid. However, dihydroxyphenyl acetic acid concentration was higher than in control cases. The CSF SOD level was not significantly from that in control cases. The changes in neurochemical substances in the CSF support their use as markers of cerebrovascular disease-related change.