Differential Reward Learning for Self and Others Predicts Self-Reported Altruism

In social environments, decisions not only determine rewards for oneself but also for others. However, individual differences in pro-social behaviors have been typically studied through self-report. We developed a decision-making paradigm in which participants chose from card decks with differing rewards for themselves and charity; some decks gave similar rewards to both, while others gave higher rewards for one or the other. We used a reinforcement-learning model that estimated each participant''s relative weighting of self versus charity reward. As shown both in choices and model parameters, individuals who showed relatively better learning of rewards for charity – compared to themselves – were more likely to engage in pro-social behavior outside of a laboratory setting indicated by self-report. Overall rates of reward learning, however, did not predict individual differences in pro-social tendencies. These results support the idea that biases toward learning about social rewards are associated with one''s altruistic tendencies.     

Separation of yeast proteasome subunits. Immunoreactivity with antibodies against ATP-dependent protease Ti from Escherichia coli

On two-dimensional gel electrophoresis, proteasomes (multicatalytic proteinase complexes) from the yeast Saccharomyces cerevisiae were separated into a characteristic set of approximately 20 components with molecular weights of 21,000 to 31,000 and isoelectric points of 3.5 to 7.5. The main components were isolated by reverse-phase high performance liquid chromatography on a TSK gel phenyl-5PW RP column and named YC1 to YC11, in order of their elution. Immuno-blot analysis showed that two components (YC1-alpha and YC1-beta) with molecular weights of 30,800 and 28,300 strongly cross-reacted with antibody against the P-component of ATP-dependent protease Ti from Escherichia coli, but no components were found to react with antibodies against the A-component of protease Ti or another ATP-dependent protease La (the Ion gene product) of Escherichia coli. These results indicate a structural relationship between eukaryotic proteasomes and bacterial ATP-dependent protease Ti.     

The significance of pollination time and frequency and of purity of pollen loads for seed set in Rhinanthus angustifolius (Scrophulariaceae) and Viscaria vulgaris (Caryophyllaceae)

Summary The effects of time of the day and frequency of application and of purity of artificially deposited pollen loads on fruiting and seed set were studied in Rhinanthus angustifolius (diurnally visited by bumblebees) and Viscaria vulgaris (diurnally visited by bumblebees, nocturnally by sphingid moths).Time of the day did not influence pollination success in either species. Increase of pollination frequency increased fruiting and seed set in Rhinanthus but had no affect on Viscaria. Five successive artificial pollinations were needed to achieve seed set equal to that observed naturally in Rhinanthus while a single artificial pollination was sufficient in Viscaria. Mixing Lupinus and Viscaria pollen did not reduce fruiting and seed set in Viscaria. The results are discussed in relation to observed seed sets in early and late flowers, and small and large patches of Viscaria vulgaris and among Rhinanthus flowers in populations of different densities.     

Basic trypsin-subtilisin inhibitor from marine turtle egg white: Hydrodynamic and inhibitory properties

A basic trypsin-subtilisin inhibitor has been isolated from the egg white of marine turtle (Caretta caretta Linn.) and purified to homogeneity by gel filtration followed by ion-exchange chromatography. It has a single polypeptide chain of 117 amino acid residues, having a molecular weight of 13,600. It lacks methionine and tryptophan. Its isoelectric point is atpH 10.0 and the sedimentation coefficient (s_20,w) value of 1.62 S is independent of protein concentration. It has a Stokes radius of 18.8 Å, an intrinsic viscosity of 0.048 dl g^–1 and a diffusion coefficient of 10.17×10^–7 cm² sec^–1. Its fluorescence emission spectrum is similar to that of free tyrosine and the bimolecular quencing rate constant of its tyrosine residues with acrylamide is 3.15×10⁹ M^–1 sec^–1. The inhibitor strongly inhibits both trypsin and subtilisin by forming enzyme-inhibitor complexes at a molar ratio of unity. The nature of inhibition toward both enzymes is not temporary. It has independent binding sites for inhibition of trypsin and subtilisin. Chemical modification with tetranitromethane suggests the presence of three tyrosine residues on the surface of the inhibitor molecule.     

Transference numbers, polyion mobilities, and charge fractions in aqueous solutions of lithium, sodium, and potassium dextransulfate

Results of Hittorf type transference number measurements are reported for aqueous solutions of lithium, sodium, and potassium dextransulfate (DS) in the concentration range 0.008-0.09 moles of sulfate groups per liter. The results for the polyion transference number are combined with equivalent conductance measurements reported earlier to calculate the polyion equivalent conductance, and the polyion charge fraction based on Wall's method. Our results show that the transference number of this high charge density polyion is larger than unity over the entire concentration range studied, and decreases monotonously with increasing concentration. The calculated charge fraction f of the polyion increases with increasing concentration, and at any concentration/decreases in the order LiDS > NaDS > KDS. A comparison between the conclusions derived from these transport experiments and from both mean and single ion activity measurements in dextransulfate solutions shows the considerable uncertainties involved in either of these methods, and emphasizes the need for the application of a variety of techniques, including spectroscopic techniques, to determine differential ion binding by polyions.     

The binding of divalent metal ions to polyelectrolytes in mixed counterion systems. I. The dye spectrophotometric method

The dye spectrophotometric method for the measurement of the activity of divalent metal ions in polyelectrolyte solutions containing added electrolytes is discussed.The method is applied to mixtures containing the dextransulfate polyanion, NaCl, and MgCl2 or Ca2. A two wavelength ratio method as applied to polyelectrolyte solutions is compared to the standard method which makes use of the previous determination of the dye-metal ion formation constant. The ratio method is found to be a convenient and reliable method which is not influenced by decomposition of the dye or by statistical errors in the extrapolation procedure. The activity coefficients as determined by the two wavelength dye spectrophotometric method are compared to results of Donnan exclusion measurements, and of EMF measurements using a calcium ion selective electrode. The results of the spectrophotometric method are equal to those of the two other methods within the limits of error in the latter. The spectrophotometric measurements can extend to much lower ion activaties than the other two methods, and can be done in the presence of a large excess of added electrolyte, yielding results of considerably improved precision when compared to Donnan and EMF methods.     

The binding of divalent metal ions to polyelectrolytes in mixed counterion systems. II. Dextransulfate-Mg2+ and dextransulfate-Ca2+ in solutions containing added NaCl or KCl

Measurements of magnesium and calcium ion activities in solutions of the polyelectrolyte dextransulfate, with added sodium chloride or potassium chloride are presented. A two wavelength dye spectrophotometric method is used. Dextransulfate concentrations Cp (expressed as moles sulfate ion/litre) vary between 0.001 and 0.007, total ionic strengths between 0.005 and 0.08 mole/XXX. Divalent metal ion concentrations are varied between 0 and 1.2 Cp. The results for the metal ion activities are expressed in the form of parameters theta2 = C2/Cp (C(2bp) = bound divalent metal ion concentration) and K2 = theta2/(C2-C2b). For each divalent/univalent counterion pair the values obtained for theta2 and K2 as a function of C2,Cp, and ionic strength are compared to predictions of the "two variable theory" developed for these mixed counterion systems by Manning. This comparison shows that the observed decrease in theta2 with increasing ionic strength at fixed C2 and Cp is generally well predicted by the two variable theory. The extent of divalent ion binding at a given C2, Cp, and ionic strength is largest for the Ca/Na counterion combination, and lowest for the Mg/K combination.     

Identification of envelope protein epitopes that are important in the attenuation process of wild-type yellow fever virus.

Monoclonal antibodies (MAbs) have been prepared against vaccine and wild-type strains of yellow fever (YF) virus, and envelope protein epitopes specific for vaccine (MAbs H5 and H6) and wild-type (MAbs S17, S18, S24, and S56) strains of YF virus have been identified. Wild-type YF virus FVV, Dakar 1279, and B4.1 were each given six passages in HeLa cells. FVV and B4.1 were attenuated for newborn mice following passage in HeLa cells, whereas Dakar 1279 was not. Examination of the envelope proteins of the viruses with 87 MAbs showed that attenuated viruses gained only the vaccine epitope recognized by MAb H5 and lost wild-type epitopes recognized by MAbs S17, S18, and S24 whereas the nonattenuated Dakar 1279 HeLa p6 virus did not gain the vaccine epitope, retained the wild-type epitopes, and showed no other physical epitope alterations. MAb neutralization-resistant (MAbr) escape variants generated by using wild-type-specific MAbs S18 and S24 were found to lose the epitopes recognized by MAbs S18 and S24 and to acquire the epitope recognized by vaccine-specific MAb H5. In addition, the MAbr variants became attenuated for mice. Thus, the data presented in this paper indicate that acquisition of vaccine epitopes and loss of wild-type epitopes on the envelope protein are directly involved in the attenuation process of YF virus and suggest that the envelope protein is one of the genes encoding determinants of YF virus pathogenicity.     

Cultivation characteristics of immobilized Aspergillus oryzae for kojic acid production

Aspergillus oryzae in situ grown from spores entrapped in calcium alginate gel beads was used for the production of kojic acid. The immobilized cells in flask cultures produced kojic acid in a linear proportion while maintaining the stable metabolic activity for a prolonged production period. Kojic acid was accumulated up to a high concentration of 83 g/L, at which the kojic acid began to crystallize, and, thus, the culture had to be replaced with fresh media for the next batch culture. The overall productivities of two consecutive cultivations were higher than that of free mycelial fermentation. However, the production rate of kojic acid by the immobilized cells was suddenly decreased with the appearance of central cavernae inside the immobilized gel beads after 12 days of the third batch cultivation.