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.     

Exponential Megapriming PCR (EMP) Cloning—Seamless DNA Insertion into Any Target Plasmid without Sequence Constraints

We present a fast, reliable and inexpensive restriction-free cloning method for seamless DNA insertion into any plasmid without sequence limitation. Exponential megapriming PCR (EMP) cloning requires two consecutive PCR steps and can be carried out in one day. We show that EMP cloning has a higher efficiency than restriction-free (RF) cloning, especially for long inserts above 2.5 kb. EMP further enables simultaneous cloning of multiple inserts.     

Calculation of accurate small angle X-ray scattering curves from coarse-grained protein models

Background  

Genome sequencing projects have expanded the gap between the amount of known protein sequences and structures. The limitations of current high resolution structure determination methods make it unlikely that this gap will disappear in the near future. Small angle X-ray scattering (SAXS) is an established low resolution method for routinely determining the structure of proteins in solution. The purpose of this study is to develop a method for the efficient calculation of accurate SAXS curves from coarse-grained protein models. Such a method can for example be used to construct a likelihood function, which is paramount for structure determination based on statistical inference.     

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.     

Structure and immunochemistry of an oligosaccharide repeating unit of the capsular polysaccharide of type III group B Streptococcus. A revised structure for the type III group B streptococcal polysaccharide antigen

We have derived oligosaccharides from the capsular polysaccharide of type III group B Streptococcus by enzymatic hydrolysis of a specific backbone glycosidic bond utilizing an endo-beta-galactosidase from Flavobacterium keratolyticus. Enzymatic digestion of the polysaccharide produced oligosaccharide fragments of one or more pentasaccharide repeating units. On the basis of 13C NMR, 1H NMR, and methylation analyses, it was established that the smallest digestion fragment was alpha-D-NeupNAc-(2----3)-beta-D-Galp-(1----4)-[beta-D-Glcp-(1----6 )]- beta-D-GlcpNAc-(1----3)-beta-D-Gal. The isolation of this oligosaccharide is consistent with the susceptibility of the beta-D-Galp-(1----4)-beta-D-Glcp linkage in the backbone of the type III group B streptococcal polysaccharide and confirms that the polysaccharide is composed of a pentasaccharide repeating unit. High resolution 13C NMR spectroscopic studies indicated that, as in the case of the pentasaccharide, the terminal sialic acid residues of the type III group B streptococcal polysaccharide were linked to O-3 and not to O-6 of its branch beta-D-galactopyranosyl residues as had been previously reported (Jennings, H. J., Rosell, K.-G., and Kasper, D. L. (1980) Can. J. Chem. 58, 112-120). This linkage was confirmed in an independent methylation analysis of the type III group B streptococcal polysaccharide. Thin layer chromatogram binding assay and radioactive antigen binding assays with radiolabeled oligosaccharides demonstrated the single repeating unit pentasaccharide oligosaccharide to be poorly antigenic. Increasing oligosaccharide size to a decasaccharide consisting of two repeating units resulted in an 8-fold increase in antigen binding in the direct radioactive antigen binding assay. The results suggest that a region of the immunodeterminant site critical for antibody binding is located in the backbone of the polysaccharide and involves the beta-D-galactopyranose-(1----4) beta-D-glucopyranose bond.