Why kin and group selection models may not be enough to explain human other-regarding behaviour

Models of kin or group selection usually feature only one possible fitness transfer. The phenotypes are either to make this transfer or not to make it and for any given fitness transfer, Hamilton's rule predicts which of the two phenotypes will spread. In this article we allow for the possibility that different individuals or different generations face similar, but not necessarily identical possibilities for fitness transfers. In this setting, phenotypes are preference relations, which concisely specify behaviour for a range of possible fitness transfers (rather than being a specification for only one particular situation an animal or human can be in). For this more general set-up, we find that only preference relations that are linear in fitnesses can be explained using models of kin selection and that the same applies to a large class of group selection models. This provides a new implication of hierarchical selection models that could in principle falsify them, even if relatedness--or a parameter for assortativeness--is unknown. The empirical evidence for humans suggests that hierarchical selection models alone are not enough to explain their other-regarding or altruistic behaviour.     

The role of context in risky choice

Human choice behavior was assessed in a concurrent-chain schedule, where two equal initial links (IL) each led to a distinct terminal-link (TL). One TL was associated with a fixed ratio schedule of reinforcement, while the other was associated with a bi-valued mixed ratio schedule of reinforcement, whose arithmetic mean equaled the Fixed TL schedule. The fixed component (FR50; FR25; FR5) was arranged to be equal to the alternative mixed component in each condition (FR1/99; FR1/49; FR1/9), and choice behavior was measured by proportion of responses to each IL. In addition, the IL duration varied across conditions (VI 30 s; VI 15 s; FI 1 s). Preference for the mixed option was observed with longer durations (e.g., when IL = VI 30 s and TL = FR1/99). Participants were relatively indifferent in other conditions, though the results suggested a monotonic increase in preference as either durations or programmed efforts increased. It is concluded that both choice and the conditioned reinforcement value of the mixed option is contextually based, so that the value of a stimulus correlated with an immediate reward (i.e., FR 1) is enhanced the greater the temporal context in which the FR1 is embedded.     

前体饲喂、诱导子和光照联合使用对葡萄细胞培养合成花青素的影响

苯丙氨酸前体饲喂分别和环糊精、葡聚糖、茉莉酸甲酯、黑曲霉和直喙镰孢菌提取液五种诱导子联合作用,其中以与茉莉酸甲酯的联合作用对葡萄细胞培养生产花青素的影响最大,可使单位鲜细胞花青素含量提高2.7倍,花青素产量提高3.4倍,实验证明两者在培养后第4天加入效果最好。在30μmol/L苯丙氨酸、218μmol/L茉莉酸甲酯和3000~4000lx光照条件下,不同花青素产量的细胞株都能显著提高花青素产量,但低产株VV06比高产株VV05具有更大的产率提高潜力。该条件下VV05和VV06花青素产量分别达到2975和4090CV/L,是对照组的2.5倍和5.2倍。     

Elicitor-induced hydroxycinnamoyl-CoA:tyramine hydroxycinnamoyltransferase in plant cell suspension cultures

Treatment of Nicotiana glutinosa L. cell suspension cultures with chitosan results in the co-induction of phenylalanine ammonia lyase, 4-eoumarate:CoA ligase, tyrosine decarboxylase and tyramine hydroxycinnamoyltransferase, all involved in the biosynthesis of hydroxycinnamoyltyramines. The highest enzyme activities were observed around 12 h after addition of 0.8 to 1 mg chitosan per g fresh weight of cells. No hydroxycinnamoyltyramines could be detected by TLC or HPLC of extracts made from non-treated or elicited cells. [¹⁴C]-Tyramine was incorporated into insoluble polymeric material at a higher rate in elicitor-treated than in non-treated cells of N. glutinosa. Tyramine hydroxycinnamoyltransferase could be induced in suspension cultured cells of Eschscholtzia califortnca Cham, but not in cells of Phaseolus vulgaris L. or Catharanthus roseus (L.) G. Don by addition of a yeast elicitor to the growth medium.     

Highly efficient strategy for enhancing taxoid production by repeated elicitation with a newly synthesized jasmonate in fed-batch cultivation of Taxus chinensis cells

A highly efficient bioprocessing strategy was developed for enhancing the production of plant secondary metabolites by repeatedly eliciting a fed-batch culture with a newly synthesized powerful jasmonate analog, 2,3-dihydroxypropyl jasmonate (DHPJA). In suspension cultures of a high taxuyunnanine C (Tc)-producing cell line of Taxus chinensis, 100 microM DHPJA was added on day 7 to fed-batch cultures with feeding of 20 g L(-1) sucrose on the same day. The synergistic effect of elicitation and substrate feeding on Tc biosynthesis was observed, which resulted in higher Tc accumulation than that by elicitation or sucrose feeding alone. More interestingly, both specific Tc yield (i.e., Tc content) and volumetric yield was further improved by a second addition of 100 microM DHPJA (on day 12) to the fed-batch cultures. In particular, with repeated elicitation and sucrose feeding the Tc volumetric yield was increased to 827 +/- 29 mg L(-1), which was 5.4-fold higher than that of the nonelicited batch culture. Furthermore, the above novel strategy was successfully applied from shake flask to a 1-L airlift bioreactor. A high Tc production and productivity of 738 +/- 41 mg L(-1) and 33.2 +/- 1.9 mg L(-1) d(-1), respectively, was achieved, which is higher than previous reports on Tc production in bioreactors. The results suggest that the aforementioned bioprocessing strategy may potentially be applied to other cell culture systems for efficient production of plant secondary metabolites.     

A probabilistic network for the diagnosis of acute cardiopulmonary diseases

In this paper, the development of a probabilistic network for the diagnosis of acute cardiopulmonary diseases is presented in detail. A panel of expert physicians collaborated to specify the qualitative part, which is a directed acyclic graph defining a factorization of the joint probability distribution of domain variables into univariate conditional distributions. The quantitative part, which is a set of parametric models defining these univariate conditional distributions, was estimated following the Bayesian paradigm. In particular, we exploited an original reparameterization of Beta and categorical logistic regression models to elicit the joint prior distribution of parameters from medical experts, and updated it by conditioning on a dataset of hospital records via Markov chain Monte Carlo simulation. Refinement was iteratively performed until the probabilistic network provided satisfactory concordance index values for several acute diseases and reasonable diagnosis for six fictitious patient cases. The probabilistic network can be employed to perform medical diagnosis on a total of 63 diseases (38 acute and 25 chronic) on the basis of up to 167 patient findings.     

Variation in the growth and biosynthetic activity of cloned cell cultures of Capsicum frutescens and their response to an exogenously supplied elicitor

Twenty clones established from single cells of a suspension culture of Capsicum frutescens were maintained as callus and in suspension over a sixteen week culture period. These clones exhibited marked differences in growth, chlorophyll and chloroform-soluble phenolic content which became more apparent with increasing time in culture. Clones in suspension exhibited a more rapid change in morphology and biosynthetic activity than those cultured as callus. Elicitation increased PAL activity, reduced the incorporation of L-[U-¹⁴C] phenylalanine into the chloroform-soluble fraction of the culture medium and increased incorporation into the methanol-soluble fraction of the cells in ten suspension clones. Differences to elicitation were observed among clones; in particular the faster growing isolates incorporated more radioactive label into soluble phenolics that remain in the cells than those that are released into the medium. The implications of these results are discussed.Abbreviations SH Schenk & Hildebrandt - PAL phenylalanine ammonia-lyase - RGR relative growth rate - TCC total chlorophyll content - HPLC high performance liquid chromatography     

Interaction of cotton tissue culture cells andVerticillium dahliae

Summary Elicitation of sesquiterpenoid aldehyde phytoalexins inGossypium arboreum cell suspension cultures was confirmed by thin layer chromatography, high performance reverse phase liquid chromatography, and an aniline-reaction assay after inoculation with heat-treated conidia ofVerticillium dahliae A 2.3X mean increase in total terpenoids was observed. Component phytoalexins varied, with either hemigossypol and gossypol being detected or the O-methylated terpenoids hemigossypol-6-methyl ether and related compounds. Long-termGossypium suspension cultures were mixoploid with an increase in chromosome number and mean DNA content. Addition ofV. dahliae elicitor(s) to the medium for embryo-proliferating callus ofG. hirsutum inhibited growth and embryo production with a linear correlation (r=−0.87;P<0.01) between the elicitor concentration and the number of embryos. Addition of¹⁴C-labeled NaOAc to suspension cells gave 30% incorporation, and from¹³C-NaOAc addition, labeled sesquiterpenoid aldehydes were recovered. The cotton-Verticillium system is another case of secondary metabolite elicitation in plant tissue culture and might be used for basic studies of hostpathogen interaction as well as for a selection tool to obtain resistance to an important disease.