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.     

Experimental chemotherapy of radiation injury with synthetic lysophospholipid analogs in mice

Synthetic lysophospholipids represent a variety of analogs of the naturally occurring 2-lysophosphatidylcholine. Some of these compounds showed significant therapeutic effects on the survival of mice following radiation injury when administered after various doses of whole-body X irradiation. Such therapeutic effects were discernible even when the treatment was given 6 hr after irradiation, and both intravenous and oral application were effective. Intravenous application of 2 X 25 mg/kg lysophospholipid after whole-body X irradiation around the LD50 resulted in significantly higher numbers of surviving animals. The mode of action remains speculative.     

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.     

Natural and Chernobyl-caused radioactivity in mushrooms,mosses and soil-samples of defined biotops in SW Bavaria

Summary Different mushrooms, mosses and corresponding soil samples have been collected mainly from two sites in the alpine region of southwestern Bavaria. At the end of the growthseason, September 1986, gamma spectroscopic analysis showed that the moss-, mould, and needle-layer contained considerably more ¹³⁴Cs and ¹³⁷Cs activity per unit fresh weight than eight different species of mushroom. These two isotopes were carried into the biotop mainly as a consequence of the Chernobyl accident. ¹³¹J could not be found any more in the samples ca. 5–6 months after the catastrophe. The activity of the cesium isotopes decreased with increasing soil depth. In the mushrooms the activity was relatively high in Xerocomus badius and surprisingly low in Boletus edulis; samples of the latter and of Cantharellus cibarius collected in September 1985 (before the accident) and kept deep frozen contained almost identical amounts of ¹³⁷Cs as those collected from August to October 1986. Mushrooms contained considerably more of the natural isotope ⁴⁰K than the needlelayers and the soil samples in the neighbourhood. In all mushrooms except Xerocomus badius the activity of ⁴⁰K was generally higher than the ¹³⁷Cs activity. The results indicate that except Xerocomus badius the analyzed mushrooms do not actively take up Cs from the soil, in contrast to K.     

A Saccharomyces cerevisiae genomic plasmid bank based on a centromere-containing shuttle vector

A set of genomic plasmid banks was constructed using the centromere-containing yeast shuttle vector YCp50. The centromere-containing vector is useful for the isolation of genes that are toxic to yeast when present in high copy number. Fourteen independent banks were prepared each with an average representation of two to three times the yeast genome. Any individual plasmid from a given bank is guaranteed to be of independent origin from plasmids obtained from each of the other banks. The banks were constructed from three different size classes of DNA fragments that resulted from varying conditions of partial digestion with Sau3A. This avoided the bias caused by differential sensitivity of sites to cleavage with Sau3A. Insert DNA is sufficiently large that most genes will be present in the set of plasmid banks at a frequency of about 0.1%.     

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.     

Conformational states of beta-lactamase: molten-globule states at acidic and alkaline pH with high salt

We present evidence that beta-lactamase is close to fully unfolded (i.e., random coil conformation) at low ionic strength at the extremes of pH and that the presence of salt causes a cooperative transition to a conformation with the properties of a molten globule, namely, a compact state with native-like secondary structure but disordered side chains (tertiary structure). The conformation of beta-lactamase I from Bacillus cereus was examined over the pH 1.5-12.5 region by circular dichroism (CD), tryptophan fluorescence, dynamic light scattering, and 1-anilino-8-naphthalenesulfonate (ANS) binding. Under conditions of low ionic strength (I = 0.05) beta-lactamase was unfolded below pH 2.5 and above pH 11.5, on the basis of the far-UV and near-UV CD and tryptophan fluorescence. However, at high ionic strength and low pH an intermediate conformation (state A) was observed, with a secondary structure content similar to that of the native protein but a largely disordered tertiary structure. The transition from the unfolded state (U) to state A induced by KCl was cooperative and had a midpoint at 0.12 M KCl (I = 0.17 M) at pH 1.6. A similar conformation (state B) was observed at high pH and high ionic strength. The transition from the alkaline U state to state B induced by KCl at pH 12.2 was cooperative and had a midpoint at 0.6 M KCl (I = 0.65 M). Light scattering measurements showed that state B was compact although somewhat expanded compared to the N state. The compactness of state A could not be determined due to its strong propensity to aggregate.(ABSTRACT TRUNCATED AT 250 WORDS)