Heartbeat and Economic Decisions: Observing Mental Stress among Proposers and Responders in the Ultimatum Bargaining Game

The ultimatum bargaining game (UBG), a widely used method in experimental economics, clearly demonstrates that motives other than pure monetary reward play a role in human economic decision making. In this study, we explore the behaviour and physiological reactions of both responders and proposers in an ultimatum bargaining game using heart rate variability (HRV), a small and nonintrusive technology that allows observation of both sides of an interaction in a normal experimental economics laboratory environment. We find that low offers by a proposer cause signs of mental stress in both the proposer and the responder; that is, both exhibit high ratios of low to high frequency activity in the HRV spectrum.     

Plasmid-coded degradation of ethylbenzene and 1-phenylethanol in Pseudomonas fluorescens

Abstract Pseudomonas fluorescens EB carries genes for the catabolism of ethylbenzene and 1-phenylethanol on a plasmid. The size of the plasmid as measured by analysis of agarose electrophoresis gels after restriction endonuclease hydrolysis, was 253–267 kb. By treatment with Mitomycin C, mutants of EB strain were obtained bearing a plasmid which had undergone an extensive deletion of about 80 kb. These mutants have lost the ability to grow on ethylbenzene and 1-phenylethanol as well as to synthesize meta-cleavage enzymes.     

Glucosinolate contents in maca (Lepidium peruvianum Chacón) seeds, sprouts, mature plants and several derived commercial products

Several products derived from processed maca hypocotyls (Lepidium peruvianum Chacón, previously known asL. meyenii Walp.) were surveyed for glucosinolate content and quantified by HPLC analysis. These included pills, capsules, flour, liquor, tonic and mayonnaise. Different plant organs such as fresh hypocotyls and leaves, seeds, dry hypocotyls, and sprouts were also included in the survey. The most abundant glucosinolates detected in fresh and dry hypocotyls and leaves were the aromatic glucosinolates, benzylglucosinolate (glucotropaeolin) and p-methoxybenzylglucosinolate. Maca seeds and sprouts differed in profile from hypocotyls and leaves due to the modification of benzylglucosinolate. No glucosinolates were detected in liquor and tonic, while mayonnaise had only trace amounts of those glucosinolates. It had instead allylglucosinolate (sinigrin), which is an aliphatic glucosinolate. The pills, capsules and flour had the same glucosinolates as those observed in hypocotyls, but in variable amounts. The richest sources of glucosinolates were seeds, fresh hypocotyls and sprouts, in that order.     

Ethanol Administration in the Rat Decreases Prostacyclin Production by Isolated Brain Microvessels

The effects of short- and long-term ethanol administration to rats on basal levels and formation of prostacyclin (PGI2) measured as 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and on lipid class content and fatty acid composition of isolated brain microvessels (BMV) were studied. After acute treatment (2 h, at the peak of plasma ethanol concentration) basal 6-keto-PGF1 alpha levels in BMV and release on incubation were reduced to 50% of control values. After chronic administration (15 days), PGI2 release was reduced to about 40% of control values, without changes in basal levels. Total lipid, phospholipid, and cholesterol levels in BMV, measured after prolonged administration of alcohol, were not modified. Also, only minor changes in the fatty acid composition of individual phospholipid classes were detected. The observed reduction of PGI2 synthesis in BMV thus could not be related to changes of the fatty acid precursor pool in the preparation. Precursor release and/or the biosynthetic pathways may be affected by ethanol administration.     

Ultrastructural cytochemical and autoradiographic demonstration of nonspecific esterase(s) in guinea pig basophils

We used ultrastructural autoradiographic and cytochemical methods to localize esterase activities in unstimulated guinea pig basophils and in basophils undergoing degranulation or recovery from degranulation. We used tritium-labeled diisopropylfluorophosphate (DFP) as a probe for serine enzymes and localized this probe by ultrastructural autoradiography to cytoplasmic granules of immature or mature unstimulated basophils, as well as to granules released by degranulating basophils. Ultrastructural cytochemistry using alpha naphthyl acetate (ANA) as substrate localized nonspecific esterase activity to extruded granules, either within the interiors of degranulation sacs or within granules completely separated from degranulating basophils. Extruded granules retained their esterase activity for as long as 24 hr after antigen-induced degranulation. The plasma membranes of unstimulated or degranulating basophils, as well as of basophils recovering from degranulation, displayed prominent cell surface ANA esterase ectoenzyme activity. Lipid bodies, organelles present in the cytoplasm of both control and recovering basophils, were also alpha naphthyl acetate esterase (ANAE)-positive. Thus, cytochemical and autoradiographic techniques localized esterase and/or [3H]-DFP-binding activities to cytoplasmic granules, lipid bodies, and cell surface of basophils, and these enzyme activities persisted during both degranulation and recovery from degranulation.     

Stimulation of arachidonic acid metabolism by CCl4 in isolated rat hepatocytes

Arachidonic acid metabolism was evaluated in isolated rat hepatocytes after CCl4 exposure. CCl4 induced dose-dependently the synthesis and release of prostacyclin (PGI2) and thromboxane (TXB2). Treatment with prostaglandin E2 (PGE2) 30 min after exposure to CCl4, significantly reduced the cell damage as well as the release of TXB2 from the cells.     

Use of regularly structured bacterial cell envelope layers as matrix for the immobilization of macromolecules

Summary Carboxyl groups present on the outer face of the hexagonally ordered S-layer lattices from Bacillus stearothermophilus PV72 and Clostridium thermohydrosulfuricum L111-69 were activated with carbodiimide. The reaction of the activated carboxyl groups with free amino groups of low molecular weight nucleophiles was controlled by labelling with polycationized ferritin, a net positively charged topographical marker for electron microscopy, which densely binds to S-layers possessing free carboxyl groups. Carbodiimide-activated carboxyl groups were also allowed to react with amino groups of ferritin (MW 440 000) and invertase (MW 270 000). Covalent attachment of ferritin was examined by electron microscopy. Using invertase, approximately 1 mg enzyme was bound per mg S-layer protein indicating a high packing density of invertase molecules on the outer face of the S-layer lattice. The immobilized invertase retained 70% of its original activity.