Effects of pressure and pressure antagonists on the growth and membrane-bound ATP-ase of Acholeplasma laidlawii B

1. Arrhenius plots of the membrane-bound ATP-ase were constructed at pressures of 300, 600 and 900 atm. Pressure shifts the plots to higher temperatures with an increase in slope. 2. These data are partially consistent with a kinetic model in which a phase transition in the lipids associated with the ATP-ase determines the activity of the enzyme. They are also consistent with a model in which the non-linear Arrhenius plot is caused by the low temperature inactivation of the enzyme, upon which pressure acts directly. 3. Pentanol inhibits the ATP-ase without affecting the Arrhenius break temperature, and therefore does not act by affecting the phase-state of lipids associated with the enzyme. The pentanol-enzyme interaction yielded the following: delta H 46 Kcal mol-1 and delta S 114 cal mol-1 deg-1. 4. Pressure inhibits cell growth in a way which is partially offset by comparable partial pressures of helium and hydrogen. Its action probably involves the ordering of the membrane bilayer which is counteracted by the fluidising effect of the gases.

[Sedative-hypnotic compounds in the exhalation of hops, II]

Hops are told to promote sleep; manyfold efforts to detect the soporific principle have been unsuccessful so far. Preliminary pharmacological tests lead to the conclusion that the soporific activity of the exhalation of hops can be explained by its content of 2-methyl-3-butene-2-ol (1) in the volatile fraction. It was found that 1, when given to mice i.p. (0.80 g/kg) produces narcosis for about 8 h; no abnormal behaviour was observed there upon. Due to its water-solubility the concentration of 1 in the essential oil obtained by steam-distillation is low; contrary to that, 1, is enriched in the more volatile fraction of hops.

The electrostatic contribution to binding in the choline transport system of erythrocytes

Half-saturation constants have been determined for the choline carrier with cationic substrates and their uncharged carbon analogs: (a) choline and 3,3-dimethyl-1-butanol and (b) 2-dimethylaminoethanol and isoamyl alcohol. The constants are 6.3 microM and 16 mM for the first pair, and 19 microM and 45mM for the second. In both cases, the charged molecules have the higher affinity by a factor of more than 2000. This is to be compared with a factor of less than 10 for charged and neutral substrates of acetylcholinesterase, and with a similar factor in antigen-antibody reactions. To account for the unusually strong ionic bond, a very close association between the carrier site and the substrate is suggested, probably with exclusion of water of hydration. This is supported by the fact that gradual replacement of N-methyl groups in the substrate by N-ethyl groups sharply reduces affinity for the carrier with a 110-fold reduction overall, but has no significant effect on the enzymes.

Rate of decrease of glutamyltransferase and acid phosphatase activities in the human vagina after coitus

I studied the rate at which gamma-glutamyltransferase (EC 2.3.2.2) and acid phosphatase (EC 3.1.3.2) activities decrease in the healthy human vagina after coitus. Specimens from the coital and non-coital vagina, and from the rectum and buccal cavity, and pre-ejaculate lubricating fluid were also assayed for both enzymes. Prostatic acid phosphatase was determined with use of two substrates: thymolphthalein monophosphate and alpha-naphthyl phosphate (tartrate-inhibitable fraction). Glutamyltransferase was assayed with gamma-glutamyl-p-nitroanilide as substrate. All non-coital specimens were negative for glutamyltransferase activity; the activity of acid phosphatase varied with type of substrate and type of specimen. The equation y = a + (b/x) describes the decline in activity (y) of either acid phosphatase or glutamyltransferase in the vagina of healthy women post-coitally with time (x).

Unilateral lesions of the olfactory tubercle modifying general arousal effects in the rat olfactory bulb

The centrifugal control exerted by different arousal states on the rat olfactory bulb was investigated. The olfactory tubercle was unilaterally coagulated with either 1 mA or 3 mA current. The vigilance state parameters and multiunit mitral cell activity were recorded in freely moving rats, stimulated either by their usual food odor or by isoamyl acetate, in a hungry or a satiated state. In each animal, a unilateral lesion affected resting activity and the relative proportion of positive (excitatory) and negative (inhibitory) responses in the same way in both olfactory bulbs; these effects were proportional to the extent of the lesion. In wakefulness, a nutritional modulation of the bulb responses for food odor existed in spite of a slight decrease in the general arousal level. In slow wave sleep (SWS), when compared to a control group, the rats with lesions showed an increase of neocortical desynchronization induced by olfactory stimulation, and a large decrease of mitral cell excitability. Inhibition of the olfactory input, which normally develops during SWS, could involve mainly mesencephalic neurons reaching the olfactory tubercle and the bulb via the ventral part of the medial forebrain bundle.

Pharmacokinetics and pharmacodynamics of ethanol, whiskey, and ethanol with n-propyl, n-butyl, and iso-amyl alcohols

Plasma ethanol concentration, reaction time, and electroencephalogram (EEG) were recorded in 6 normal men after ingestion of ethanol along (Group 1), whiskey (Group 2), or a mixture of ethanol, n-propanol, n-butanol, and iso-amyl alcohol (Group 3). The peak plasma ethanol concentration and the total area under the plasma concentration:time curve of ethanol did not depend upon the type of drink given, but the half-life of the terminal exponential phase of ethanol elimination was longer in Group 3. In each study period reaction time increased, there was a relative increase in delta activity (2 to 3 Hz) and a fall in mean dominant frequency in EEG activity. The extent of increase in reaction time depended on the rate of increase in plasma ethanol concentration and correlated with the concentration of ethanol while the plasma concentration of ethanol was falling. Differences in the effects of ethanol between study periods were minimal.

Biological effects of 2,4-pentadiene-1-ol

The biological effects of 2,4-pentadiene-1-ol (CH2 = CH--CH = CH--CH2--OH) the starting monomer in the preparation of a biocompatible polymer were studied. The experiments in rats revealed both a high local (oedema, necrosis) and systemic toxicity. Within 5-10 min after dermal application of 0.2 ml the compound evoked intensive hyperaemia of acral parts (ears, snout, paws) and induced severe breathing difficulties which led to death in half of the animals after a single administration. The most evident macroscopic and microscopic pathologic changes were found in the place of application and in the lungs (haemorrhage in alveolae). Both clinical and histological findings indicated that the toxicity is due to an increased permeability of capillaries.

Variation in the direction of selection applied by pentenol to the alcohol dehydrogenase locus in Drosophila melanogaster

This paper describes selective effects of pentenol-impregnated media on six genotypes at the alcohol dehydrogenase (Adh) locus in D. melanogaster. In the laboratory population studied, developmental times of pre-adults homozygous for an alcohol dehydrogenase "null" allele increased with increasing pentenol concentrations. The developmental times of the other five genotypes, which produced active alcohol dehydrogenases, increased slightly at pentenol concentrations up to 0-0033%, but above this concentration they decreased markedly. In fact on 0-067% pentenol, the highest concentration tested, developmental times of these five genotypes were between 9 and 24 h less than their developmental times on media lacking pentenol. The magnitude of the reduction in developmental time differed significantly between genotypes and was positively correlated with alcohol dehydrogenase activity. Pentenol had toxic effects on adults and significant differences were found between survival percentages of adults of different genotypes on pentenol-impregnated media. These survival percentages were negatively correlated with alcohol dehydrogenase activities. Therefore selective differences between genotypes in adult survival were negatively correlated with those in developmental times. The variations in the direction of selection are discussed in terms of their possible biochemical basis and their effects on the maintenance of Adh polymorphisms.

Preferential inhibition of phosphatidyl ethanolamine synthesis in E. coli by alcohols

Growth of E. coli in the presence of alcohols of chain lengths 1 through 8 results in an increase in the relative abundance of phosphatidyl glycerol. This results primarily from the preferential inhibition of phosphatidyl ethanolamine synthesis. This inhibition appears to be unrelated to membrane fluidity or to changes in fatty acid composition caused by alcohols. Alcohol-induced changes in total fatty acid composition are reflected in all phospholipid classes. Phosphatidyl serine synthetase is proposed as the most likely site for the effects of alcohols on phospholipid synthesis.

[Activation of acid prostate phosphatase by 1-pentanol (author's transl)]

The activity of the acid phosphatase from prostate was increased by 90% by the addition of 150 mmol/l 1-pentanol to the assay mixture. This activation results in an increased turnover of substrate, so that the phosphomonoester is cleaved more rapidly and a correspondingly larger amount of the release organic residue can be detected. The quantity of free phosphate, however, does not correspond to the substrate turnover, because some of the phosphate residue is transferred from the substrate to the 1-pentanol in a transphosphorylation reaction. The influence of the substrate, buffer, pH and of tartrate on the 1-pentanol-activated prostate phosphatase was investigated.

Effects of some -OH scavengers on the radiation sensitization of bacterial spores by p-nitroacetophenone and O2 in suspension

Spores of Bacillus megaterium were irradiated in suspension with 50 kVp X-rays under three reference conditions: in anoxia (i.e., 100 per cent N2); in anoxia with 2mM p-nitroacetophenone (PNAP), a concentration that shows the maximum amount of sensitization by this agent; and in air. The responses were then measured when different concentrations of an hydroxyl radical scavenger were also present. Allyl alcohol, t-amyl alcohol, t-butanol, ethanol, glycerol, the formate ion, and methanol were the -OH scavengers that were used. A comparison of the effects these additives have on the three reference responses provides indirect, comparative information on the sensitizing processes of PNAP and O2. Neither t-amyl alcohol nor t-butanol affects the response in air or N2 alone. Both these additives, however, can reduce the sensitization from PNAP slightly. The other additives have significant protective effects under the three conditions. In general, the additives have similar effects in air and in 100 per cent N2 but much greater protective effects in PNAP. Although the sensitizing mechanisms are not identified by these experiments, the effects of O2 and PNAP, as judged by the desensitizing actions of these additives, appear quite different.

Modulation of 2,3-diphosphoglycerate 31P-NMR resonance positions by red cell membrane shape

Na+ transport in the red cells of the dog is dependent on cell volume, a 20% change in cell volume leading to a 25-fold increase in apparent Na+ flux; the effect is dependent upon metabolic energy. We have found that swelling and shrinking dog red cells causes a shift in the 31P-NMR peak of 2,3-diphosphoglycerate, which is present in dog red cells at 5.5 mM. Control experiments indicate that the 2,3-diphosphoglycerate resonance peak shifts may not be attributed to: interaction with hemoglobin, changes in cell pH, ionic strength, diamagnetic susceptibility or small changes in the Mg2+/2,3-diphosphoglycerate ratio. Experiments with chlorpromazine and pentanol which alter red cell membrane area by a mechanism different from osmotic swelling suggest that 2,3-diphosphoglycerate interacts with a binding site in the cell that is dependent upon the physical condition of the dog red cell membrane.

Hypocholesterolemic agents III: inhibition of beta-hydroxy-beta-methylglutaryl coenzyme A reductase by half acid esters of 1-(4-biphenylyl)pentanol

A series of half acid esters of 1-(4-biphenylyl)pentanol was synthesized and assayed for inhibition of rat liver beta-hydroxy-beta-methylglutaryl coenzyme A reductase. The number of methylenes separating the carboxyl and ester groups was varied from zero to six. A minimum of one methylene was required for reasonable activity. Further separation of the carboxyl and ester groups produced small changes in activity. Investigation of several isomeric (cis and trans) half acid esters indicated that activity was independent of configuration. Modification of the acid portion of the glutarate analog by incorporating a 3-hydroxyl group increased activity sixfold.

beta-D-galactosidase activity in single yeast cells during cell cycle of Saccharomyces lactis

Single Saccharomyces lactis cells taken from a random population were assayed for beta-D-galactosidase activity under a microscope equipped for fluorogenic measurements. The cells were also photographed, and enzymatic activity was correlated to the size of cell buds. A perodic pattern of enzyme synthesis was found during the cell cycle.

Inhibitory action of aliphatic alcohols on smooth muscle contraction

The addition of 0.05-0.20 mM CaCl2 to the isolated guinea pig ileum immersed in a depolarizing (excess potassium), and calcium-free Tyrode solution produces a dose-related contraction, which is reversibly blocked by aliphatic alcohols of low molecular weight. The inhibitory potency of the alcohols increases with the length of their carbon chain, and may be due to an interference with the movement of calcium across the smooth muscle cell membrane.

Effects of formaldehyde and ozone on the trigeminal nasal sensory system

The effects of formaldehyde and ozone on the electrical activity of the nasopalatine nerve were studied in anesthetized rats. The response (increase in action potential frequency) of nasopalatine and ethmoidal nerves to brief presentations of formaldehyde, ozone, or amyl alcohol was a power function of stimulus concentration. When formaldehyde was presented continuously for one hour, it produced a decrease in nasopalatine nerve response to amyl alcohol that varied directly with the formaldehyde concentrations employed. Perfusion of the nasal cavities with air for one hour following the formaldehyde exposure resulted in a partial recovery of the neural response to amyl alcohol. Ozone exposures of 5 ppm lasting one hour produced an increase in nasopalatine nerve response to amyl alcohol. Air perfusion following the ozone exposure reduced the neural response to amyl alcohol, but not to preexposure levels.