The effect of ethylene, octanoic acid and a plant-derived smoke extract on the germination of light-sensitive lettuce seeds

The effects of an aqueous plant-derived smoke extract, octanoic acid and ethylene on germination of light-sensitive Grand Rapids lettuce seeds were investigated. The smoke extract brought about a concentration dependent increase in germination and a complete inhibition of germination at high concentrations. Octanoic acid could not induce germination. Ethylene at concentrations over 5 L L^–1 increased lettuce seed germination, but not to the same degree as smoke. Aqueous smoke in combination with ethylene showed a synergistic effect on germination at suboptimal smoke concentrations. At high smoke concentrations the effect of ethylene was almost completely inhibited. Octanoic acid in combination with ethylene brought about a higher level of germination than with ethylene alone, but only at the highest concentration of octanoic acid tested (1 mM). Standardized hexane and dichloromethane-partitioned smoke extracts and octanoic acid were subjected to TLC separation. The R _f -fractions in the smoke lanes showing activity in the lettuce seed bioassay did not correspond to the R _f -value of octanoic acid. As aqueous smoke can withstand autoclaving and can be separated by TLC and HPLC without loosing activity it is unlikely that the activity of aqueous smoke is linked to ethylene. It thus appears that the active compound in smoke is neither octanoic acid nor ethylene.Abbreviations TLC thin layer chromatography - HPLC High performance liquid chromatography     

Activation of plasma membrane ATPase of Saccharomyces cerevisiae by octanoic acid.

Plasma membrane ATPase activity of Saccharomyces cerevisiae IGC 3507III grown in the presence of the lipophilic acid octanoic acid [4-50 mg l-1 (0.03-0.35 mM), pH 4.0] was 1.5-fold higher than that in cells grown in its absence. The Km for ATP, the pH profile and the sensitivity to orthovanadate of the basal and the activated forms of the membrane ATPase were identical. This activation was closely associated with a decrease in the biomass yield and an increase in the ethanol yield, and was rapidly reversed in vivo after removal of the acid. However, the activated level was preserved when membranes were extracted and subjected to manipulations which eliminated or decreased octanoic acid incorporation in the plasma membrane. The activity of the basal plasma membrane ATPase in the total membrane fraction was slightly increased by incubation at pH 6.5 with octanoic acid at 100 mg l-1 or less (2.4 mg acid form plus 97.6 mg octanoate ion l-1). However, destruction of the permeability barrier between the enzyme and its substrate could not explain the in vivo activation. A role for plasma membrane ATPase activation in the regulation of the intracellular pH (pHi) of cells grown with octanoic acid was not proven.     

Tailor-made olefinic medium-chain-length poly[(R)-3-hydroxyalkanoates] by Pseudomonas putida GPo1: batch versus chemostat production

Functionalized medium-chain-length polyhydroxyalkanoates (mclPHAs) have gained much interest in research on biopolymers because of their ease of chemical modification. Tailored olefinic mclPHA production from mixtures of octanoic acid and 10-undecenoic acid was investigated in batch and dual (C,N) nutrient limited chemostat cultures of Pseudomonas putida GPo1 (ATCC 29347). In a batch culture, where P. putida GPo1 was grown on a mixture of octanoic acid (58 mol%) and 10-undecenoic acid (42 mol%), it was found that the fraction of aliphatic monomers was slightly lower in mclPHA produced during exponential growth than during late stationary phase. Thus, the total monomeric composition changed over time indicating different kinetics for the two carbon substrates. Chemostat experiments showed that the dual (C,N) nutrient limited growth regime (DNLGR) for 10-undecenoic acid coincided with the one for octanoic acid. Five different chemostats on equimolar mixtures of octanoic acid and 10-undecenoic acid within the DNLGR revealed that the monomeric composition of mclPHA was not a function of the carbon to nitrogen (C(0)/N(0)) ratio in the feed medium but rather of the dilution rate. The fraction of aliphatic monomers in the accumulated mclPHA was slightly lower at high dilution rates and increased towards low dilution rates, again indicating different kinetics for the two carbon substrates in P. putida GPo1.     

Inactivation of lipid enveloped viruses by octanoic Acid treatment of immunoglobulin solution.

Inactivation of lipid enveloped viruses by treatment with octanoic acid has been investigated for three intravenous immunoglobulin preparations, using Human Immunodeficiency Virus, Bovine Viral Diarrhoea Virus, Sindbis Virus and Pseudorabies Virus as test viruses. At a concentration of 7.45 g octanoic acid per kg solution complete inactivation of lipid enveloped viruses to below detectable level (>5.36, >4.68, >6.25 and >5.55 log(10), respectively) was achieved within the first minutes of treatment. Octanoic acid treatment as described here, has been demonstrated as an effective and rapid virus inactivation procedure, which shows high robustness at the tested ranges of temperature, pH and protein content of the test material. However, pH must be considered as a critical parameter of treatment, as octanoic acid fails to inactivate lipid coated viruses at basic pH. At suitable conditions, e.g. pH<6.0 and a concentration of >3.7 g/kg, octanoic acid treatment gives reliable and highly effective inactivation of lipid enveloped viruses.     

Fatty Acid Transport Through the Blood-Brain Barrier

Across the cerebral capillaries, the anatomical locus of the blood-brain barrier, the unidirectional influxes of the saturated fatty acids, octanoic and myristic acids, and the unsaturated essential fatty acid, linoleic acid, were measured. Employing an in situ rat brain perfusion technique that allows control of perfusate composition and accurate measurement of perfusate-to-brain fatty acid transport, we found that both [¹⁴C]octanoic and [¹⁴C]myristic acids were transported through the blood-brain barrier in vivo, in large part, by a specific, probenecid-sensitive transport system. However, the transport of [¹⁴C]linoleic acid was not probenecid sensitive. With 0.5 μM fatty acid but no plasma proteins in the perfusate, the permeability-surface area constant was higher for myristic acid (4.8 × 10^--²× s^-1) than for octanoic and linoleic acids (1.5 and 1.2 × 10^--²× s^-1, respectively). Approximately 70, 30, and 25% of the [¹⁴C]myristic, [¹⁴C]octanoic, or [¹⁴C]linoleic acids, respectively, were extracted from the perfusate.     

Thioethyl-, Vinyl-, Ethyl Octanoate Esters and Octanoic Acid as Acyl Donors in Lipase Catalysed Acyl Transfer Reactions

S-Ethyl thiooctanoate, vinyl octanoate, ethyl octanoate and octanoic acid were studied as acyl donors in a lipase catalysed acyl transfer reaction with 2-octanol as acyl acceptor. The reaction conditions had a pronounced effect on the equilibrium displacement and the apparent enantioselectivity. The thioethyl and vinyl esters proved to be efficient acyl donors under atmospheric pressure and 39 d`C, affording a high apparent enantiomeric ratio. Under these reaction conditions the apparent enantioselectivity seemed to be enhanced by water, which was present in the reaction system and caused the production of octanoic acid, by hydrolysis of me acyl enzyme.     

Effect of octanoic acid on the insulin secretion in response to glucose in vitro (author's transl)

The effect of octanoic acid (1.5 mM) on insulin secretion in 4.4 and 16.7 mM glucose stimulation has been studied in rat's isolated and perfused pancreas. The absence of octanoic acid does not produce any significant insulin secretion increase in response to 4.4 mM glucose infusion, whereas its presence produces a significant insulinic response of a monophasic nature. Both in the presence and absence of octanoic acid, the 16.7 mM glucose-stimulation produces a biphasic insulin secretion. The octanoic acid enhances both the first and the second phase of insulin secretion. The present results show that octanoic acid clearly potentiates the insulin secretion in response to 4.4 mM and 16.7 mM glucose.     

Gavaserin and saltavalin, new peptide antibiotics produced by Bacillus polymyxa

Abstract A strain of Bacillus polymyxa (BP1), isolated from cauliflower seeds, inhibited the growth of microbial phytopathogens. Growth of this strain in liquid medium containing lactose, ammonium sulfate, biotin, and amino acids, resulted in optimal inhibition in vitro. Two new antibacterial substances were isolated and purified from culture broth. Their molecular masses were, respectively, 911 and 903 dallons. The first compound was named gavaserin because it contained glutamic acid, alanine, valine, serine and 2,4-diaminobutyric acid, and octanoic acid. No fatty acid was detected in the second compound, which was named saltavalin because it contained serine, alanine, leucine, threonine, valine, and 2,4-diaminobutyric acid.     

A new class of nonionic detergents with a gluconamide polar group

Detergents containing either a cholic acid, a deoxycholic acid, or an octanoic acid-like hydrophobic moiety and a bisgluconamidopropyl polar group were synthesized. Extinction coefficients, partial specific volumes, critical micelle concentrations, and aggregation numbers were determined for each of the detergents. The two bile acid derivatives are capable of solubilizing functional opiate receptor, while the octanoic acid derivative is not.     

Effect of the non-steroidal anti-inflammatory drugs on the acyl-CoA synthetase activity toward medium-chain,long-chain and polyunsaturated fatty acids in mitochondria of mouse liver and brain

Effect of eleven non-steroidal anti-inflammatory drugs on the acyl-CoA synthetase activities toward octanoic, palmitic, arachidonic and docosahexaenoic acids was evaluated in mouse liver and brain mitochondria. The drugs tested were aspirin, salicylic acid, diflunisal, mefenamic acid, indomethacin, etodolac, ibuprofen, ketoprofen, naproxen, loxoprofen, flurbiprofen. In mouse liver mitochondria, diflunisal and mefenamic acid exhibited the inhibitory activities not only for octanoic acid (IC₅₀?=?78.7 and 64.7 µM) and but also for palmitic acid (IC₅₀?=?236.5 and 284.4 µM), respectively. Aspirin was an inhibitor for the activation of octanoic acid only (IC₅₀?=?411.0 µM). In the brain, mefenamic acid and diflunisal inhibited strongly palmitoyl-CoA formation (IC₅₀?=?57.3 and 114.0 µM), respectively. The activation of docosahexaenoic acid in brain was sensitive to inhibition by diflunisal and mefenamic acid compared with liver.     

Carbon 13 NMR studies of saturated fatty acids bound to bovine serum albumin. II. Electrostatic interactions in individual fatty acid binding sites

13C NMR chemical shift results as a function of pH for a series of carboxyl 13C-enriched saturated fatty acids (8-18 carbons) bound to bovine serum albumin (BSA) are presented. For octanoic acid bound to BSA (6:1, mol/mol), the chemical shift of the only FA carboxyl resonance (designated as peak c), plotted as a function of pH, exhibited a complete sigmoidal titration curve that deviated in shape from a corresponding theoretical Henderson-Hasselbach curve. However, FA carboxyl chemical shift plotted as a function of added HCl yielded a linear titration curve analogous to those obtained for protein-free monomeric fatty acid (FA) in water. The apparent pK of BSA-bound octanoic acid was 4.3 +/- 0.2. However, the intrinsic pK (corrected for electrostatic effects resulting from the net positive charge on BSA) was approximately 4.8, a value identical to that obtained for monomeric octanoic acid in water in the absence of protein. For long-chain FA (greater than or equal to 12 carbons) bound to BSA (6:1, mol/mol), chemical shift titration curves for peak c were similar to those obtained for octanoic acid/BSA. However, the four additional FA carboxyl resonances observed (designated as peaks a, b, b', and d) exhibited no change in chemical shift between pH 8 and 3. For C14.0 X BSA complexes (3:1 and 6:1, mol/mol) peaks b' and a exhibited chemical shift changes between pH 8.8 and 11.5 concomitant with chemical shift changes in the epsilon-carbon (lysine) resonance. In contrast, peaks c and d exhibited no change and peak b only a slight change in chemical shift over the same pH range. We conclude: the carboxyl groups of bound FA represented by peaks a, b, b', and d were involved in ion pair electrostatic interactions with positively charged amino acyl residues on BSA; the carboxyl groups of bound FA represented by peak c were not involved in electrostatic interactions with BSA; the similarity of the titration curves of peak c for BSA-bound octanoic acid and long-chain FA suggested that short-chain and long-chain FA represented by peak c were bound to the same binding site(s) on BSA; bound FA represented by peaks b' and a (but not d or b) were directly adjacent to BSA lysine residues. We present a model which correlates NMR peaks b, b', and d with the putative locations of three individual high-affinity binding sites in a three-dimensional model of BSA.     

At-line determination of octanoic acid in cultivation broth--an electronic tongue (ET) feasibility study

Production monitoring of "natural" 2-heptanone from octanoic acid in an industrial fed-batch cultivation based on Penicillium roqueforti requires development of a method for determination of octanoic acid dissolved in the water phase. An electronic tongue array using six non-specific potentiometric sensors with solid inner contact, and a pH electrode, has been introduced by spiking octanoic acid to a substrate obtained from four different cultivations, representing variations in the relevant industrial matrix. Multivariate calibration was performed on acid concentrations spanning 0.65-20 mmol l(-1). Excluding the lowest concentration a global Partial Least Square regression model with a predicted versus measured correlation of 0.98 and a relative root mean square error of prediction of 5.1% (ln units) (RPD=5.5) signifies a highly acceptable prediction facility. This model was further tested by subjecting it to undiluted as well as diluted samples obtained from a cultivation process in which octanoic acid was catabolized; this led to acceptable prediction errors within the same range as for the global model. It is concluded that the ET sensor array can be applied for determination of octanoic acid in cultivation systems of the general P. roqueforti type.     

Drosophila simulans' response to laboratory selection for tolerance to a toxic food source used by its sister species D. sechellia

Drosophila sechellia is a specialist species which feeds and breeds on a toxic plant, Morinda citrifolia. All other Drosophila species are killed by ripe fruits of Morinda. D. simulans was subjected to laboratory selection for survival in presence of octanoic acid, the toxic compound of M. citrifolia. After 20 generations of selection, selected lines showed an increased tolerance to octanoic acid, although the response was small compared to the interspecific differences. The genetic response to selection was assessed by studying the changes in allele frequencies at 28 microsatellite loci. Three loci, located in three distinct genomic regions, showed changes in allele frequencies significantly different from what is expected under drift alone in the selected lines. An oligogenic determination for tolerance to octanoic acid is in agreement with published results based on interspecific crosses.     

Mechanisms underlying the acquisition of resistance to octanoic-acid-induced-death following exposure of Saccharomyces cerevisiae to mild stress imposed by octanoic acid or ethanol

Acquisition of resistance to lethal concentrations of octanoic acid was induced in cells of Saccharomyces cerevisiae grown in the presence of sublethal concentrations of this lipophilic acid or following rapid exposure (1 h) of unadapted yeast cells to mild stress imposed by the same acid. Experimental evidence indicated that the referred adaptation involved de novo protein synthesis, presumably due to the rapid induction of a plasma membrane transporter which mediates the active efflux of octanoate out of the cell. Rapid exposure of cells to mild ethanol stress also led to increased resistance to lethal concentrations of octanoic acid. This cross-resistance to octanoic-acid-induced death was below the level of resistance induced by mild octanoic acid stress and did not involve induction of the active expulsion of octanoate out of the cell. However, the rapid exposure of yeast cells to octanoic acid or ethanol led to the activation of plasma membrane H+-ATPase. The physiological role of the two stress responses examined during the present study, namely, the active efflux of octanoate specifically induced by octanoic acid and the stimulation of plasma membrane H+-ATPase activity, is discussed.     

Inhibition of Choline Acetyltransferase Activity by Serum Albumin Modified with Octanoic Acid and Other Fatty Acids

In this study, we examined the effect of fatty acids on choline acetyltransferase (ChAT) activity. ChAT is unstable in a solution of low protein concentration, so serum albumin (BSA) is usually added to stabilize the enzyme. However, we found that ChAT from bovine caudate nucleus rapidly lost its activity when diluted with a buffer containing commercial preparations of BSA. This effect was caused by octanoic acid, which was found in the gas chromatography/mass spectrometry system of lipid extract in commercial BSAs. The inhibition of ChAT activity by octanoic acid depended on the concentrations of the octanoic acid and of the albumin. We also found that ChAT activity was decreased by some long-chain fatty acids, arachidonic acid having exhibited the strongest effect. The extent to which arachidonic acid inhibited ChAT activity depended on the molar ratio of arachidonic acid and albumin, rather than upon the concentration of arachidonic acid. The effect of octanoic acid and arachidonic acid on ChAT activity appeared to increase in the presence of albumin.     

Lipoic acid metabolism in Escherichia coli: sequencing and functional characterization of the lipA and lipB genes.

Two genes, lipA and lipB, involved in lipoic acid biosynthesis or metabolism were characterized by DNA sequence analysis. The translational initiation site of the lipA gene was established, and the lipB gene product was identified as a 25-kDa protein. Overproduction of LipA resulted in the formation of inclusion bodies, from which the protein was readily purified. Cells grown under strictly anaerobic conditions required the lipA and lipB gene products for the synthesis of a functional glycine cleavage system. Mutants carrying a null mutation in the lipB gene retained a partial ability to synthesize lipoic acid and produced low levels of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase activities. The lipA gene product failed to convert protein-bound octanoic acid moieties to lipoic acid moieties in vivo; however, the growth of both lipA and lipB mutants was supported by either 6-thiooctanoic acid or 8-thiooctanoic acid in place of lipoic acid. These data suggest that LipA is required for the insertion of the first sulfur into the octanoic acid backbone. LipB functions downstream of LipA, but its role in lipoic acid metabolism remains unclear.     

Influence of homologous n-alkanoic on functional properties of isolated skeletal muscles. II. Membrane resting potential and the osmotic effectiveness of alkanoic acid]

The influence of butyric, hexanoic, octanoic, and decanoic acid on the membrane resting potential of isolated frog skeletal muscles were studied and the osmotic effects of n-alkanoic acids tested. 1. n-alkanoic acids cause osmotic effects like impermeable non-electrolytes (sucrose). Therefore, the permeability to alkanoic acids of the resting muscle cell membrane seems to be small. There are no differences between the acids tested. 2. The membrane resting potential is differently affected. Butyric acid in high concentration effects a hyperpolarization of the membrane whereas higher homologues (C6--C10) cause a depolarization. The depolarizing action increases with increasing concentration, exposure, and with the length of the hydrocarbon chain of the alkanoic acids. 3. It is suggested that osmotic effects are the cause for hyperpolarization of the membrane by high concentrations of butyric acid. 4. The depolarizing action of hexanoic, octanoic, and decanoic acid is discussed with regard to alterations induced by alkanoic acids in the membrane permeability and/or in the metabolism of the cells.     

Effect of octanoic acid on ethylene-mediated flower induction in Dutch iris

Treatment of Dutch iris (Iris × hollandica Hoog. cv. Sapphire Beauty) bulbs with ethylene prior to precooling stimulated flowering in bulbs of various sizes. In large sized bulbs exposure to ethylene followed by precooling resulted in 100% flowering over a five months period after planting. Flowering in control bulbs which were not treated with ethylene prior to precooling was limited to 67% during the same five months period. In medium sized bulbs flowering in the ethylene treatment was 90% compared to 75% in the control. However, the biggest stimulation of flowering by ethylene was found in small sized bulbs (from 16 to 56%). Application of octanoic acid for a short time period prior to exposure to ethylene stimulated flowering in all bulb sizes. After five months the final percentage flowering in large and medium sized bulbs of the octanoic acid plus ethylene treatment did not differ from that of the ethylene only treatment. However, the initial rate of flowering was higher in the former treatment. In small bulbs the percentage flowering was much higher in the octanoic acid plus ethylene treatment than in the ethylene only treatment. The results of this study indicate that, just as in certain flowers, fruit and seeds, treatment with octanoic acid stimulates ethylene sensitivity in Dutch iris bulbs. The sensitivity of untreated bulbs to ethylene was highest in large bulbs and lowest in small bulbs. This correlated well with the endogenous octanoic acid content of the bulbs. Octanoic acid levels were highest in large bulbs and lowest in small Bulbs. It appears that the endogenous levels of octanoic acid in the bulbs is determined prior to the onset of dormancy.     

Allosteric and competitive displacement of drugs from human serum albumin by octanoic acid, as revealed by high-performance liquid affinity chromatography, on a human serum albumin-based stationary phase

A chiral stationary phase for high-performance liquid chromatography, based upon immobilized human serum albumin (HSA), was used to investigate the effect of octanoic acid on the simultaneous binding of a series of drugs to albumin. Octanoic acid was found to bind with high affinity to a primary binding site, which in turn induced an allosteric change in the region of drug binding Site II, resulting in the displacement of compounds binding there. Approximately 80% of the binding of suprofen and ketoprofen to HSA was accounted for by binding at Site II. Octanoic acid was found to also bind to a secondary site on HSA, with much lower affinity. This secondary site appeared to be the warfarin—azapropazone binding area (drug binding Site I), as both warfarin and phenylbutazone were displaced in a competitive manner by high levels of octanoic acid. The enantioselective binding to HSA exhibited by warfarin, suprofen and ketoprofen was found to be due to differential binding of the enantiomers at Site I; the primary binding site for suprofen and ketoprofen was not enantioselective.     

Inhibition of Yeast Growth by Octanoic and Decanoic Acids Produced during Ethanolic Fermentation

The inhibition of growth by octanoic or decanoic acids, two subproducts of ethanolic fermentation, was evaluated in Saccharomyces cerevisiae and Kluyveromyces marxianus in association with ethanol, the main product of fermentation. In both strains, octanoic and decanoic acids, at concentrations up to 16 and 8 mg/liter, respectively, decreased the maximum specific growth rate and the biomass yield at 30°C as an exponential function of the fatty acid concentration and increased the duration of growth latency. These toxic effects increased with a decrease in pH in the range of 5.4 to 3.0, indicating that the undissociated form is the toxic molecule. Decanoic acid was more toxic than octanoic acid. The concentrations of octanoic and decanoic acids were determined during the ethanolic fermentation (30°C) of two laboratory media (mineral and complex) by S. cerevisiae and of Jerusalem artichoke juice by K. marxianus. Based on the concentrations detected (0.7 to 23 mg/liter) and the kinetics of growth inhibition, the presence of octanoic and decanoic acids cannot be ignored in the evaluation of the overall inhibition of ethanolic fermentation.