Polymyxin E production by P. amylolyticus.

AIMS: To investigate antibiotic production by bacteria isolated from the hindgut of Tipula abdominalis, the aquatic crane fly. METHODS AND RESULTS: A group of five isolates with 99.1% 16S rRNA sequence similarity to Paenibacillus amylolyticus were identified as antibacterial producers using the cross-streak method against both Gram-positive and Gram-negative bacteria. For one isolate, P. amylolyticus C27, biochemical tests were performed to confirm 16S rRNA identification and the antibacterials were purified using chromatographic methods. Postsource decay (PSD) mass spectroscopy (MS) was used to identify the antimicrobials, which were found to be polymyxins E(1) and E(2). Investigation of the remaining four isolates using PSD MS revealed they all produce polymyxins E(1) and E(2) as well. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Although variants of the polymyxin antibiotics are known to be produced by several species within the Paenibacillus genus, this first investigation of antibacterial production by bacteria isolated from the hindgut of T. abdominalis describes a novel source for polymyxin E production as well as the first report of antibiotic production by P. amylolyticus.

Reliability and validity of alcohol-induced heart rate increase as a measure of sensitivity to the stimulant properties of alcohol.

RATIONALE: Alcohol-induced heart rate (HR) stimulation during the rising limb of the blood alcohol curve reliably discriminates between individuals at differential risk for alcoholism, and appears to be a potential psychophysiological index of psychomotor stimulation from alcohol. OBJECTIVES: Three studies are presented which explore the reliability and convergent and discriminant validity of this alcohol response index. METHODS: Young men with and without a multigenerational family history of alcoholism were administered a 1.0 ml/kg dose of 95% USP alcohol. Resting baseline cardiac and subjective measures were assessed before and after alcohol consumption. RESULTS: Study 1 demonstrated that alcohol-induced HR stimulation was significantly and positively related to alcohol-induced changes in mood. Study 2 demonstrated that alcohol-induced HR stimulation was reliable across two alcohol administration sessions (r=0.33-0.66, P<0.01). Study 3 explored the relationship between the proposed index and measures of sensitivity to alcohol previously linked to genetic predisposition to alcoholism. Multiple regression analysis indicated that alcohol-induced HR increase and reduced subjective intoxication (measured using the Subjective High Assessment Scale) were both positively associated with alcohol-induced changes in mood states that have previously been shown to be sensitive to the effects of stimulant drugs and the reinforcing effects of alcohol. CONCLUSIONS: Sensitivity to alcohol-induced heart-rate stimulation during the ascending limb of the blood alcohol curve may be a useful and informative marker for understanding susceptibility to alcoholism.

Enzymatic hydrolysis of ammonia-treated sugar beet pulp.

Sugar beet pulp is a carbohydrate-rich coproduct generated by the table sugar industry. Beet pulp has shown promise as a feedstock for ethanol production using enzymes to hydrolyze polymeric carbohydrates and engineered bacteria to ferment sugars to ethanol. In this study, sugar beet pulp underwent an ammonia pressurization depressurization (APD) pretreatment in which the pulp was exploded by the sudden evaporation of ammonia in a reactor vessel. APD was found to substantially increase hydrolysis efficiency of the cellulose component, but when hemicellulose- and pectin-degrading enzymes were added, treated pulp hydrolysis was no better than the untreated control.

Biphasic effects of alcohol on heart rate are influenced by alcoholic family history and rate of alcohol ingestion.

The present study investigated cardiac response to acute alcohol challenge along the blood alcohol concentration (BAC) curve in two groups of young adult nonalcoholic men with (MFH) and without (FH-) multigenerational family histories of alcoholism, matched for drinking history. BACs and resting heart rate measurements were recorded every 10 min for 3 hr after ingestion of a 1.0 ml/kg dose of 95% USP alcohol at two different rates: one of 20 min (slow drinking) and the other of 5 min (fast drinking). Several analyses of variance were performed for each of the dependent measures [BAC and heart rate change from baseline (HRCH)]. A significant risk x BAC phase interaction emerged from the HRCH analysis, indicating that the MFH group was characterized by a significantly greater increase in resting heart rate along the ascending limb of the BAC curve. A significant risk x BAC phase x rate interaction indicated that, when alcohol was consumed at a faster rate, men with multigenerational family histories of alcoholism demonstrated a greater HRCH, which persisted throughout the BAC curve.

Ethanol-induced change in cardiac and endogenous opiate function and risk for alcoholism.

Susceptibility to alcoholism varies with age, gender, and familial background. Youthful nonalcoholic males with multigenerational family histories of male alcoholism seem at particular risk. Previous investigations suggest that such males are characterized by abnormal psychophysiological response, while sober and alcohol-intoxicated; additional recent studies indicate that the endogenous opiate systems are involved in mediating ethanol reinforcement and modulating intake. We first compared cardiac response to alcohol administration among young (mean = 22.8 years), nonalcoholic men and women with multigenerational, unigenerational, and negative family histories of alcohol dependence and abuse. Then, we compared the ethanol-induced cardiac response of the males in these three groups to that of currently alcohol-dependent older males and age-matched nonalcoholic male controls. Finally, we examined ethanol-induced change in plasma beta-endorphin and cortisol levels among a subset of the nonalcoholic males, divided into those with high and low levels of postethanol administration heart-rate increase. Nonalcoholic males with multigenerational family histories of male alcoholism were characterized by significantly higher [t(301) = 5.70, p < 0.0001, Cohen's d = 0.73] levels of ethanol-induced heart-rate increase than nonalcoholics from all other comparison groups. The magnitude of their increase matched that of current male alcohol-dependents. Nonalcoholic males with high levels of ethanol-induced heart-rate increase also produced significantly more plasma beta-endorphin after consuming alcohol. Peak production of beta-endorphin was highly correlated (r = 0.861, p < 0.001) with magnitude of heart-rate increase. A subset of those at risk for alcoholism may be characterized by sensitivity to ethanol-induced reward, marked by heightened ethanol-induced, heart-rate increase, mediated by ethanol stimulation of endogenous opiate production. This subset might contain those who, once alcoholic, would differentially benefit from treatment with opiate antagonists.

Alcoholism: the role of different motivational systems.

Individuals use and misuse alcohol (and other drugs) because of the pharmacologically mediated effects these substances have on the operation of 4 psychobiological systems, mediating response to motivationally relevant unconditioned and conditioned stimuli. These 4 systems have unique neuroanatomical structure, biochemical modes of operation, association with affect, behavior and cognition, and responsiveness to drugs of abuse. Individual variation in the operation of these systems determines individual susceptibility to initiation and maintenance of drug use and abuse. Sources of such variation differ, in a vitally important fashion, in various specific populations of individuals at heightened risk for drug abuse. Nonalcoholic sons of male alcoholics, with multigenerational family histories of male alcoholism, appear to be at heightened risk for the development of alcohol abuse because alcohol eliminates their heightened response to threat, and because they are hypersensitive to ethanol's psychomotor stimulant effects. Anxiety-sensitive individuals also appear attracted to alcohol for its anxiolytic properties. Many other important sources of idiosyncratic variability exist. Detailed analysis of such sources may lead to the development of more effective prevention and treatment programs.

Provocation, acute alcohol intoxication, cognitive performance, and aggression.

This study investigated the relationships between provocation, acute alcohol intoxication, impaired frontal-lobe function, and aggressive behavior. The authors ranked 114 men according to their performance on two neuropsychological tests associated with frontal-lobe function. Forty-eight men (24 with scores in the upper and 24 with scores in the lower performance quartiles) participated in the full study. Half completed and aggression task while intoxicated, the remainder while sober. Aggression was defined as shock intensity delivered to a sham opponent. Shock intensity significantly increased as a main effect of provocation, alcohol intoxication, and lower cognitive performance. Furthermore, provocation interacted significantly with test performance such that individuals in the lower cognitive performance quartile responded to increased provocation with heightened aggression.

Cardiovascular reactivity as a predictor of alcohol consumption in a taste test situation.

The existence of a relationship between cardiovascular reactivity to signalled shock and alcohol consumption can be inferred from studies of males at increased familial risk for alcoholism. The present study examined two groups of nonalcoholic men--those with multigenerational histories (MGH) of alcoholism and family--history negative (FH-) controls-to determine whether reactivity was related to voluntary ethanol consumption in the context of a beverage taste test. High reactors, a significant majority of whom were MGH males, drank significantly more vodka and orange juice, rum and coke, and orange juice when asked to rate the flavor of three alcoholic and two nonalcoholic drinks. High reactors also consumed more alcohol on a weekly basis according to their self-report.

A biosocial model of the alcohol-aggression relationship.

Four of alcohol's dose- and rate-dependent pharmacological properties may increase the likelihood of human aggression. As an anxiolytic, alcohol is capable of reducing the inhibitory effect of fear on manifestation of aggressive behavior. As a psychomotor stimulant, alcohol can potentiate aggressive behavior, once evoked, or lower the threshold for such evocation. Alcohol-related disruption of certain higher order cognitive functions may reduce the inhibitory control generally exercised by previously established knowledge and decrease ability to plan in the face of threat or punishment. Finally, alcohol's ability to increase pain sensitivity may increase the likelihood of defensive aggression. Discussion of the nature and relevance of these pharmacological properties is structured according to a heuristic and synthetic schema, predicated upon consideration of an inhibitory neuropsychological structure--the individually and culturally determined general expectancy set.

Heart-rate reactivity and alcohol consumption among sons of male alcoholics and sons of non-alcoholics.

Recent studies have demonstrated that sons of male alcoholics with multigenerational family histories of male alcoholism are characterized by sober heart-rate hyperreactivity to aversive stimuli, susceptibility to alcohol-induced dampening of that hyperreactivity and by increased resting heart rate while intoxicated. Regression analyses indicate that the magnitude of alcohol-induced change in resting and reactive cardiac response is significantly and powerfully associated with the degree of self-reported voluntary alcohol consumption among 85 non-alcoholic males who are either lacking or who have moderate or extensive family histories of male alcoholism. It appears that heightened sensitivity to alcohol-induced increase in resting and decrease in reactive heart rate might mark or underlie familial risk for developing alcoholism.

Risk for alcoholism, antisocial behavior, and response perseveration.

Numerous studies have demonstrated the existence of an association between alcoholism and antisocial personality (ASP). The present study tested two hypotheses: First, that nonalcoholic men with a multigenerational familial history (MGH) of alcoholism would play more cards on a card task that has been shown previously to differentiate antisocial populations from normals and, second, that MGH subjects would display more evidence of ASP on two personality questionnaires: The Self-Report Psychopathy scale and the Socialization scale of the California Psychological Inventory. A total of 28 subjects (14 MGH and 14 family history negative for alcoholism [FH-]) were employed in this study. MGH subjects played significantly more cards during the card task than did FH- subjects. However, the two groups did not differ on the ASP questionnaires. The possibility that a subtle frontal-lobe deficit, rather than ASP per se, underlies the poorer performance of the MGH males is discussed.

Factor structure and correlates of the Tridimensional Personality Questionnaire.

Cloninger has proposed a model linking personality characteristics to patterns of responses to various stimuli, including alcohol. The model also uses personality characteristics to divide alcoholics into two types. In order to assess the relevant aspects of personality, the Tridimensional Personality Questionnaire (TPQ) was developed. This study examined the factor structure and correlates of the questionnaire to shed light on its validity. A confirmatory factor analysis of the TPQ failed to replicate the three proposed factors of novelty seeking, harm avoidance and reward dependence. Alternative models also failed to fit the data. The three factors were correlated with other personality measures theoretically linked to drinking (MacAndrew, Socialization and Sensation-Seeking scales), quantity and frequency measures of alcohol use and a measure of alcohol abuse (the Michigan Alcoholism Screening Test). The pattern of correlations provides evidence for the convergent validity of the TPQ. Nevertheless, the failure to replicate the factor structure suggests that the scale requires further revision before the model can be adequately tested.

Dependence of oxygen-tolerant nitrogenase activity on divalent cations in Azotobacter vinelandii.

Nitrogenase activity of washed Azotobacter vinelandii cells was enhanced by the addition of Ca2+ and Mg2+, and the enhancement increased with the O2 concentration. In assays provided with a level of O2 that was initially supraoptimal and inhibitory to nitrogenase activity, the addition of Ca2+ or Mg2+ affected both the maximum respiration rate (Vmax) of the cells and the apparent affinity [KS(O2)] of cell respiration for O2. Changes in these parameters correlated with changes in nitrogenase activity. Aeration-dependent increases in Vmax and KS(O2) were inhibited by rifampin and chloramphenicol and were also observed in ammonium-grown cultures.

Cognitive dysfunction and the inherited predisposition to alcoholism.

A battery of neuropsychological tests was administered to 22 nonalcoholic sons of male alcoholics (SOMAs) from families with extensive histories of male alcoholism and to 22 nonalcoholic controls with no history of familial alcoholism. In each group 11 subjects were tested while sober and 11 were tested while alcohol-intoxicated. Analyses of the results of this battery suggested (1) that SOMAs may be characterized by comparative decrements in those cognitive functions associated with the organization of novel information, dependent in theory upon the prefrontal cortex; and (2) that alcohol detrimentally affects delayed memory, associated with the temporal cortex, equally across groups. Of these SOMAs 20 had previously participated in one of two studies that demonstrated their cardiovascular hyper-reactivity to threat/stress and their increased sensitivity to the reactivity-dampening effects of alcohol intoxication. Correlational analyses of the results of the present and previous studies demonstrated the existence of a highly significant relationship between cognitive impairment, cardiovascular hyper-reactivity and susceptibility to the reactivity-dampening effects of alcohol.

Small GTP-binding proteins associated with secretory vesicles of Paramecium.

GTP-binding proteins act as molecular switches in a variety of membrane-associated processes, including secretion. One group of GTP-binding proteins, 20-30 kDa, is related to the product of the ras proto-oncogene. In Saccharomyces cerevisiae, ras-like GTP-binding proteins regulate vesicular traffic in secretion. The ciliate protist Paramecium tetraurelia contains secretory vesicles (trichocysts) whose protein contents are released by regulated exocytosis. Using [alpha-32P]GTP and an on-blot assay for GTP-binding, we detected at least seven GTP-binding proteins of low molecular mass (22-31 kDa) in extracts of Paramecium tetraurelia. Subcellular fractions contained characteristic subsets of these seven; cilia were enriched for the smallest (22 kDa). The pattern of GTP-binding proteins was altered in two mutants defective in the formation or discharge of trichocysts. Trichocysts isolated with their surrounding membranes intact contained two minor GTP-binding proteins (23.5 and 29 kDa) and one major GTP-binding protein (23 kDa) that were absent from demembranated trichocysts. This differential localization of GTP-binding proteins suggests functional specialization of specific GTP-binding proteins in ciliary motility and exocytosis.

The Tridimensional Personality Questionnaire and the inherited risk for alcoholism.

The Tridimensional Personality Questionnaire (TPQ) (Cloninger, 1987c) was administered to four groups of young men. The first group was composed of nonalcoholic sons of male alcoholics with extensive multigenerational family histories of male alcohol abuse. The second was made up of nonalcoholic men with alcoholic fathers. The third group was composed of nonalcoholic men with no family history of alcoholism, taken from the general population. The fourth group contained male undergraduates with no family history of alcoholism. There were no significant differences between the mean scores obtained by members of all four groups on the three major subscales of the TPQ.

A biobehavioural model for the inherited predisposition to alcoholism.

Sons of male alcoholics are at increased risk for the development of alcoholism, and are characterized as well by other traits, that may serve as markers for the alcoholic predisposition. These other traits include mild cognitive abnormalities, cardiac hyper-reactivity to signalled electric shock, susceptibility to alcohol-intoxication elimination of that hyper-reactivity, and increased baseline heart-rate while drinking.

Information processing, neuropsychological function, and the inherited predisposition to alcoholism.

Sons of male alcoholics are at particularly heightened risk for the development of alcoholism. This heightened risk frequently appears in association with increased incidence of conduct disorder or hyperactivity, with deficits in abstract thinking and poor school performance, with abnormalities in cued psychophysiological response, and with increased sensitivity to the putatively stress-response-dampening effects of alcohol intoxication. This risk and its associated features are discussed within the context of a neuropsychological theory, predicted on the notions (1) that deficits in cognitive functions theoretically dependent upon the intact functioning of the prefrontal cortex could underlie manifestation of the idiosyncracies commonly attributed to sons of male alcoholics, and (2) that acute alcohol intoxication could relieve the subjective discomfort associated with the consequences of such deficits.

Acute alcohol intoxication and cognitive functioning.

Acute alcohol intoxication produces changes in the cognitive functioning of normal individuals. These changes appear similar prima facie to those exhibited by individuals who sustain prefrontal lobe damage during adulthood. In order to test the validity of this observation, and to control for the confounding effects of expectancy, 72 male subjects were administered a battery of neuropsychological tests, within the context of a balanced-placebo design. Each subject received one of three widely different doses of alcohol. Analysis of the results of the cognitive test battery demonstrated that a high dose of alcohol detrimentally affects a number of functions associated with the prefrontal and temporal lobes, including planning, verbal fluency, memory and complex motor control. Expectancy does not appear to play a significant role in determining this effect. The implications of this pattern of impairment are analyzed and discussed.

Fluorescence monitoring of flavins during preparation of respiratory membranes.

Azotobacter vinelandii large and small membrane particles were examined by fluorescence spectroscopy through purification to qualitatively monitor contamination by non-respiratory flavin. Flavin was analyzed by observing the effects of reduction by dithionite or NAD(P)H and subsequent oxidation. Flavin of the large particles did not change significantly with purification on a sucrose gradient. The small particle or R3 fraction contained relatively large amounts of non-respiratory flavin. Small particles eluted from a Sepharose CL-6B column with a fluorescence peak but still contained contaminating flavin. After centrifugation on a sucrose gradient, the flavin of these particles was essentially the same as the large particles. This method is an improvement over just observation of fluorescence intensity for monitoring flavoprotein purity of membrane particle preparations.