The Influence of Climate on Flourishing and Motivational Outcomes for U.S. Masters Swimmers

The climate in which older adults exercise and participate in sport may play a role in promoting a lifetime commitment to exercising. However, little research has examined the relationship of caring (C) and task-involving (TI) climates, motivation, and well-being with respect to older adult athletes. The purpose of this study was to examine the relationship between Masters swimmers' perceptions of the climate, effort, enjoyment, and flourishing as well as explore the mediating effects of effort and enjoyment on the relationship between climate and flourishing. U.S. Masters swimmers (n = 294; M_age = 63.57 years; 84.40% White) with 1-80 years of swimming experience (M = 34.54 years) participating in coach-led programs completed an online survey. The results of latent variable, multiple-mediator analyses via structural equation modeling revealed two important contributions to the literature: (1) when Masters swimmers perceived that they were in C and TI climates, they were more likely to report higher levels of effort and greater enjoyment and flourishing; (2) the Masters swimmers' effort levels directly influenced their flourishing, mediating the relationship between climates and flourishing. This research has important implications for practice and policy, as U.S. Masters Swimming appears to be a fruitful avenue for promoting an enjoyable physical activity that can be experienced throughout a lifetime.

Functional biodiversity and plasticity of methanogenic biomass from a full-scale mesophilic anaerobic digester treating nitrogen-rich agricultural wastes

The effect of ammonia on methanogenic biomass from a full-scale agricultural digester treating nitrogen-rich materials was characterized in batch activity assays subjected to increasing concentrations of total ammonia N. Acetotrophic and methanogenic profiles displayed prolonged lag phases and reduced specific activity rates at 6.0 gN-TAN L^-1, though identical methane yields were ultimately reached. These results agreed with the expression levels of selected genes from bacteria and methanogenic archaea (qPCR of 16S rRNA and mrcA cDNA transcripts). Compound-specific isotope analysis of biogas indicated that ammonia exposure was associated to a transition in methanogenic activity from acetotrophy at 1.0 gN-TAN L^-1 to intermediate and complete hydrogenotrophy at 3.5 and 6.0 gN-TAN L^-1. Such pattern matched the results of 16S-Illumina sequencing of genes and transcripts in that predominant methanogens shifted, along with increasing ammonia, from the obligate acetotroph Methanosaeta to the hydrogenotrophic Methanoculleus and the poorly understood methylotrophic Methanomassiliicoccus. The underlying bacterial community structure remained rather stable but, at 6.0 gN-TAN L^-1, the expression level increased considerably for a number of ribotypes that are related to potentially syntrophic genera (e.g. Clostridium, Bellilinea, Longilinea, and Bacteroides). The predominance of hydrogenotrophy at high ammonia levels clearly points to the occurrence of the syntrophic acetate oxidation (SAO), but known SAO bacteria were only found in very low numbers. The potential role of the identified bacterial and archaeal taxa with a view on SAO and on stability of the anaerobic digestion process under ammonia stress has been discussed.

Effect of ammonia on the active microbiome and metagenome from stable full-scale digesters

Four full-scale anaerobic digesters with a long history of stable operation were characterized in terms of active microbiome and metagenome. Isotopic fractionation of biogas demonstrated that acetotrophy was rather prevalent in reactors operated at <3 gTAN L^-1 while hydrogenotrophy was predominant at >6 gTAN L^-1, suggesting that syntrophic acetate oxidizing bacteria (SAOB) played a significant role in the latter. These results were generally coherent with the observed active bacterial and archaeal communities but no known SAOB were observed. Metagenome descriptions yielded 73 assembled population genomes, of which only 7 could be assigned at the species level. Gene annotation and association to relevant metabolic pathways indicated that the phyla Chloroflexi and Bacteroidales might encompass new, currently undescribed, SAOB/formate producing species that would metabolize acetate via the glycine cleavage system. The predominant hydrogenotrophic counterpart at a high ammonia content belonged to the genus Methanoculleus, which could also grow on acetate to a certain extent.

Effects of enhanced denitrification on hydrodynamics and microbial community structure in a soil column system

Enhanced heterotrophic denitrification by adding glucose was investigated by means of a soil column experiment which simulated the groundwater flow. The carbon-to-nitrogen ratio was the main factor determining denitrification potential under experimental conditions. The influence of stimulated denitrification on the autochthonous microbial community was investigated by quantitative PCR (qPCR), and denaturing gradient gel electrophoresis (DGGE). The qPCR detection of the nosZ genes encoding nitrous oxide reductase, and the comparison of the abundances of 16S rRNA genes revealed that the addition of glucose enhanced denitrification leading to an increase in both the total eubacteria and, in particular, in the ratio of denitrifying bacteria, which represented the 21% of the total native eubacteria on the basis of nosZ/16S rRNA gene ratio. Microbial community profiling by DGGE indicated that ribotypes closely related to the genera Acidovorax and Hydrogenophaga (Comamonadaceae family) became enriched in the soil column. The effects of biomass occurrence in the column system on soil hydrodynamics, assessed by tracer studies, revealed a reduction of porosity and a significant increase of dispersivity that could be caused by the appearance of new functional microbial biomass in the aquifer material under enhanced denitrifying conditions. The importance of investigating the microbial growth in relation to the hydrodynamic effects, during enhanced denitrification, has been revealed in the column system experiments associated with the bioremediation. Combining microbial characterisation and hydrodynamic data in a soil column system permits us to gain an insight to the limiting factors of different stimulation strategies that can be applied in the field.

Anaerobic digestion of slaughterhouse waste: main process limitations and microbial community interactions

Fresh pig/cattle slaughterhouse waste mixtures, with different lipid-protein ratios, were characterized and their anaerobic biodegradability assessed in batch tests. The resultant methane potentials were high (270-300 L(CH4) kg(-1)(COD)) making them interesting substrates for the anaerobic digestion process. However, when increasing substrate concentrations in consecutive batch tests, up to 15 g(COD) kg(-1), a clear inhibitory process was monitored. Despite the reported severe inhibition, related to lipid content, the system was able to recover activity and successfully degrade the substrate. Furthermore, 16SrRNA gene-based DGGE results showed an enrichment of specialized microbial populations, such as β-oxidizing/proteolitic bacteria (Syntrophomonas sp., Coprothermobacter sp. and Anaerobaculum sp.), and syntrophic methanogens (Methanosarcina sp.). Consequently, the lipid concentration of substrate and the structure of the microbial community are the main limiting factors for a successful anaerobic treatment of fresh slaughterhouse waste.

Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production

Effects of a dietary intake of the polyunsaturated omega-6 essential fatty acids (EFAs) linoleic and gamma-linolenic acids (GLA) on blood lipids, platelet function, and vascular prostacyclin production were studied 12 hyperlipidemic patients (doses of 3 g/day) and 12 male Wistar rats (doses of 3 mg/kg/day) for 4 months. In humans, GLA supplementation decreased plasma triglyceride (TG) levels by 48% (p < 0.001) and increased HDL-cholesterol concentration by 22% (p < 0.01). Total cholesterol and LDL-cholesterol levels were significantly decreased by omega-6 EFAs. Platelet aggregation induced by low concentrations of adenosine diphosphate (ADP) and epinephrine, and serum thromboxane B2 decreased by 45% both in humans and animals after GLA supplementation. Bleeding time increased 40% (p , 0.01). In rats, vascular prostacyclin production measured by radioimmunoassay of 6-keto-PGF1 alpha was enhanced by GLA intake. These effects of omega-6 EFAs may contribute to cardiovascular protection and prevention of the atherosclerotic disease.

Investigations on the ethanol-induced flushing reaction: effects of propranolol and dipyridamole on acetaldehyde and prostacyclin metabolism

Disulfiram, an aldehyde dehydrogenase (ALDH) inhibitor, induces a flushing reaction upon the ingestion of ethanol, exerting aversion against alcohol that has been used in the treatment of alcoholism. This unpleasant response has been associated with an accumulation of acetaldehyde, and more recently, with an increase in vascular prostacyclin (PGI2) production. To evaluate the possibility of evoking the flushing reaction with drugs less toxic than disulfiram, we studied the effects of propranolol and dipyridamole on ALDH and PGI2. Acetaldehyde oxidation rate was assessed by gas chromatography in mitochondria from rats treated with these drugs for seven days. Prostacyclin generation was determined in rat aortic rings incubated in Krebs-Ringer with these drugs separately and associated to acetaldehyde, and measured by radioimmunoassay of 6-keto-PGF1 alpha. Propranolol inhibited acetaldehyde oxidation rate whereas dipyridamole did not. Furthermore, propranolol increased blood acetaldehyde levels without affecting ethanol elimination rate. Both drugs stimulated prostacyclin synthesis but only dipyridamole enhanced the stimulatory effect of acetaldehyde on vascular prostacyclin production. These results strongly suggest the possibility of producing a deterrent effect on the consumption of alcohol by using propranolol or dipyridamole. In contrast to disulfiram, these drugs could potentially induce the flushing reaction in humans in the presence of low acetaldehyde concentrations; this new therapeutic approach might have an important clinical and toxicological relevance.

Role of sulfhydryl groups in the stimulatory effect of captopril on vascular prostacyclin synthesis

The effect of captopril on vascular prostacyclin production was studied, evaluating which of its components--sulfhydryl (SH) group or proline--is responsible for this effect. Rat aortas were incubated with captopril (10-100 microM), 2-mercaptoethanol or proline (10 microM), and captopril plus the SH-binding reagents N-ethylmaleimide or ethacrynic acid (50 microM). Prostacyclin was measured by radioimmunoassay of 6-keto-prostaglandin F1 alpha. Captopril stimulated prostacyclin production. This effect was associated with an enhanced conversion of arachidonate to prostacyclin and was not related to bradykinin. Since 2-mercaptoethanol increased vascular prostacyclin per se and proline did not, the stimulatory effect of captopril appears to be dependent upon the SH group; in addition, both SH blockers, N-ethylmaleimide and ethacrynic acid, antagonized this effect. This study shows that captopril stimulates vascular prostacyclin synthesis directly and that the SH group plays a key role in this action. This stimulation of prostacyclin synthesis may contribute to the antihypertensive action of captopril.

Enhanced stimulatory effect of high density lipoproteins (HDL) and other agonists on vascular prostacyclin production in rats fed alcohol-containing diets

Chronic administration of liquid diets containing 36% of energy as ethanol to rats increased the serum level of high density lipoproteins (HDL) by 40% and potentiated 2 to 3-fold the stimulatory effect of these lipoproteins on the production of prostacyclin by aortic rings, as compared to pair-fed controls given isocaloric carbohydrate instead of ethanol. Cross-incubations between aortic rings and HDL from either alcohol-fed or pair-fed control rats revealed two factors operating in opposite directions. On the one hand, the predominant mechanism for the potentiation was increased reactivity of the vessel to these lipoproteins. This increased reactivity was also apparent with other agonists of prostacyclin formation. On the other hand, for equal amounts of either cholesterol or protein, the HDL from alcohol-fed rats were less stimulatory than those from controls. This was associated with a smaller content of arachidonate in the HDL of alcohol-fed rats. These ethanol effects on prostacyclin, a potent vasodilator and platelet antiaggregator, may contribute to the decreased incidence of ischemic heart disease observed in moderate alcohol drinkers.

Acute and chronic effects of ethanol and its metabolites on vascular production of prostacyclin in rats

The cutaneous vasodilation produced by ethanol is exaggerated when acetaldehyde levels are increased after aldehyde dehydrogenase inhibition, producing a flushing reaction, the mechanism of which is unknown. The authors investigated whether ethanol and its metabolites affect the vascular release of prostacyclin, a potent vasodilator, and whether such an effect might be modified by chronic alcohol consumption. Aortic rings from rats fed Chow ad libitum or pair-fed liquid diets containing either ethanol (36% of energy) or isocaloric carbohydrate for 4 to 5 weeks were incubated in Krebs-Ringer bicarbonate supplemented with saturating amounts of arachidonate (10-20 microM) in the presence of ethanol (10-100 mM), acetaldehyde (10-100 microM) or acetate (1.25-5 mM). Prostacyclin was measured by the radioimmunoassay of 6-keto-prostaglandin F1 alpha. Acetaldehyde produced a concentration-dependent stimulation of prostacyclin production both in alcohol-fed and control rats, whereas acetate did not. This effect was associated with increased conversion of arachidonate (either exogenous or released with A23187) and of prostaglandin endoperoxide H2 to prostacyclin. Ethanol did not affect prostacyclin release in control rats, but, in aortas from alcohol-fed animals, 50 mM ethanol did stimulate prostacyclin formation. These effects may contribute to the cardiovascular responses associated with high blood acetaldehyde levels in flushers and with high ethanol levels in alcoholics. In conclusion, acetaldehyde is a potent stimulant of vascular prostacyclin production. This effect is due, at least in part, to enhanced activity of prostacyclin synthase. Ethanol acquires such a stimulatory effect on prostacyclin formation after chronic alcohol consumption.

Estrogens induce lipoxygenase derivative formation in rabbit lens

The effect of estrogens on arachidonic acid metabolism was studied in lenses from normal and sex hormone-treated female rabbits. Analysis of the metabolites derived from incubation of these lenses with (1-14C) arachidonic acid provides the first evidence that estradiol activates the lipoxygenase pathway, as indicated by 5-S-hydroxy-6,8,11,14-eicosatetraenoic acid--like product formation, an effect that can be prevented by progestin treatment. Prostaglandin synthesis was not demonstrated by the control or estrogen-treated rabbit lenses, suggesting that lipoxygenase is the major arachidonic acid pathway in the lens.

Antagonistic effects of propranolol upon ethanol-induced narcosis in mice

The interaction of dl-propranolol with narcosis induced by ethanol was studied in mice. dl-propranolol reduced significantly the duration of ethanol-induced narcosis. This antagonism was also present in animals pre-treated with pyrazole. The d-isomer of propranolol, devoid of beta-blocking action, did not decrease the duration of ethanol-induced narcosis. The blood levels of ethanol at the end of narcosis were similar in animals with or without dl-propranolol pre-treatment. These results support the hypothesis that this action of dl-propranolol could be mediated by central adrenergic beta receptors.