The metabolic significance of octulose phosphates in the photosynthetic carbon reduction cycle in spinach

(14)C-Labelled octulose phosphates were formed during photosynthetic (14)CO(2) fixation and were measured in spinach leaves and chloroplasts. Because mono- and bisphosphates of d-glycero-d-ido-octulose are the active 8-carbon ketosugar intermediates of the L-type pentose pathway, it was proposed that they may also be reactants in a modified Calvin–Benson–Bassham pathway reaction scheme. This investigation therefore initially focussed only on the ido-epimer of the octulose phosphates even though (14)C-labelled d-glycero-d-altro-octulose mono- and bisphosphates were also identified in chloroplasts and leaves. (14)CO(2) predominantly labelled positions 5 and 6 of d-glycero-d-ido-octulose 1,8-P(2) consistent with labelling predictions of the modified scheme. The kinetics of (14)CO(2) incorporation into ido-octulose was similar to its incorporation into some traditional intermediates of the path of carbon, while subsequent exposure to (12)CO(2) rapidly displaced the (14)C isotope label from octulose with the same kinetics of label loss as some of the confirmed Calvin pathway intermediates. This is consistent with octulose phosphates having the role of cyclic intermediates rather than synthesized storage products. (Storage products don’t rapidly exchange isotopically labelled carbons with unlabelled CO(2).) A spinach chloroplast extract, designated stromal enzyme preparation (SEP), catalysed and was used to measure rates of CO(2) assimilation with Calvin cycle intermediates and octulose and arabinose phosphates. Only pentose (but not arabinose) phosphates and sedoheptulose 7-phosphate supported CO(2) fixation at rates in excess of 120 μmol h(−1) mg(−1) Chl. Rates for octulose, sedoheptulose and fructose bisphosphates, octulose, hexose and triose monophosphates were all notably less than the above rate and arabinose 5-phosphate was inactive. Altro-octulose phosphates were more active than phosphate esters of the ido-epimer. The modified scheme proposed a specific phosphotransferase and SEP unequivocally catalysed reversible phosphate transfer between sedoheptulose bisphosphate and d-glycero-d-ido-octulose 8-phosphate. It was also initially hypothesized that arabinose 5-phosphate, an L-Type pentose pathway reactant, may have a role in a modified Calvin pathway. Arabinose 5-phosphate is present in spinach chloroplasts and leaves. Radiochromatography showed that (14)C-arabinose 5-phosphate with SEP, but only in the presence of an excess of unlabelled ribose 5-phosphate, lightly labelled ribulose 5-phosphate and more heavily labelled hexose and sedoheptulose mono- and bisphosphates. However, failure to demonstrate any CO(2) fixation by arabinose 5-phosphate as sole substrate suggested that the above labelling may have no metabolic significance. Despite this arabinose and ribose 5-phosphates are shown to exhibit active roles as enzyme co-factors in transaldolase and aldolase exchange reactions that catalyse the epimeric interconversions of the phosphate esters of ido- and altro-octulose. Arabinose 5-phosphate is presented as playing this role in a New Reaction Scheme for the path of carbon, where it is concluded that slow reacting ido-octulose 1,8 bisphosphate has no role. The more reactive altro-octulose phosphates, which are independent of the need for phosphotransferase processing, are presented as intermediates in the new scheme. Moreover, using the estimates of phosphotransferase activity with altro-octulose monophosphate as substrate allowed calculation of the contributions of the new scheme, that ranged from 11% based on the intact chloroplast carboxylation rate to 80% using the carboxylation rate required for the support of octulose phosphate synthesis and its role in the phosphotransferase reaction

The Supply Side Determinants of Territory and Conflict

What determines the geographic extent of territory? We microfound and extend Boulding’s “Loss of Strength Gradient” to predict the extensive and intensive margins of conflict across space. We show how economies of scale in the production of violence and varying costs of projecting violence at a distance combine to affect the geographic distribution of conflict and territory. We test and probe the boundaries of this model in an experiment varying the fixed costs of conflict entry. As predicted, higher fixed costs increase the probability of exclusive territories; median behavior closely tracks equilibrium predictions in all treatments

Moral emotions – motives for (im)moral behavior?

Schools and teachers are highly relevant for the socialization of the upcoming generation who is responsible for the future global networked society. Facing the bold changes in modern societies due to globalization, educators have to foster children's and adolescents' moral growth to enable them to preserve moral and democratic values in these increasingly diversified societies. This paper provides an empirical approach to discuss how developmental research on children's and adolescents' moral emotions can help us understand how both immoral and morally relevant behavior evolve. Are moral emotions related to children's moral, prosocial behavior, as well as to their immoral, aggressive behavior? We present three studies that investigate the link between these aspects. Based on the findings we discuss how moral emotions might serve as motives for (im)moral behavior. We argue that studying how moral emotions can serve as motives for (im)moral action tendencies may not only be of conceptual significance to developmental researchers, but also of practical importance to educators. Facing the bold changes in modern societies in the course of globalization, it is highly relevant for all educators to foster children's and adolescents' moral growth to enable them to preserve moral and democratic values in increasingly diversified societies. Moreover, being able to understand themselves as socially embedded, mutually interdependent (i.e., networked) agents helps students to become more open towards and tolerant of various kinds of "other-ness", for example cultural diversity. Moral learning and understanding encompass far more than just knowing about rules and values. If these rules and values are to become relevant to the self, children and adolescents must attach valence and meaning to them and gain a deeper understanding of what it means to consider other peoples' welfare. Because emotions give meaning and valence to interactions, actions, and events (e.g., Ellsworth & Scherer, 2003) they play a central role in moral learning. Accordingly this paper provides an empirical approach to discuss how developmental research on children's and adolescents' moral emotions can help us understand how both morally relevant and immoral behaviour evolve. The central question is whether moral emotions are related to children's moral, prosocial behavior, as well as to their immoral, aggressive behaviour. We present three studies investigating the link between moral emotions and eventual (im)moral behaviour. Based on the findings we discuss how moral emotions might serve as motives for (im)moral behavior. Study 1 investigated the question how moral emotions evolve during the course of childhood by comparing at-risk children's moral emotions and moral judgments with those of children attending an ordinary elementary school. At-risk children differ from "normal" children by having problems with discipline, being more aggressive towards both teachers and classmates, and by behaving immorally and transgressing moral rules. Drawing conceptually on the happy-victimizer-approach, at-risk children were assumed to a) accept moral rule transgression more often; b) attribute positive feelings to the victimizer more often; and c) express less empathy towards the victim than control children. 80 boys aged 9 to 11 were asked to judge moral rule transgressions as well as to attribute emotions to the transgressor and to the victim and to justify these judgements and attributions. Content analysis (Mayring, 2002) was performed (Cohen's k =. 84). Although no differences were found for rule knowledge, we found notable differences regarding moral reasoning and emotion attributions. At-risk children showed a higher acceptance of rule transgressions and less moral justifications for non-acceptance. With respect to the victim, the at-risk group had difficulties attributing any emotions at all, and more frequently reported to have no idea what harming someone means as compared to control children. The results show that educating moral emotions seems to be as important as educating moral reasoning. Emotional experiences can be meaningfully used as a basis for initiating children's moral learning. Study 2 investigated the relations between physical and relational aggression and moral knowledge and emotions in a sample of 237 7- and 9-year-old primary school children. Firstly, we expected that physical aggression would be associated with deficits in moral knowledge and moral emotions. Secondly, we hypothesized that relational aggression is negatively associated with moral emotions, but is not associated with moral knowledge. Both relational and physical aggression were assessed by peer nominations and teacher ratings. Moral knowledge was measured by moral judgments and justifications of these judgments', moral emotions were measured by emotion attributions and corresponding justifications. Hierarchical regression analyses revealed that physical aggression was associated with deficits in moral knowledge and moral emotions. Relational aggression, however, was not associated with moral deficits, but with an advanced understanding of moral emotions, suggesting that children with high levels of relational aggression use their advanced understanding of moral emotion for strategic purposes. Study 3 investigated whether children's moral judgments, emotion attributions, and justifications produced in real-life narratives differ from those generated in hypothetical scenarios. The sample consisted of 190 Swiss kindergarten and primary school children. Based on Wainryb et al.'s (2005) procedure, a narrative of an own interpersonal moral transgression was elicited from each child, followed by a half-standardized interview to probe children's motives, moral judgments, justifications for these judgments, emotions attributed to both themselves (perpetrator) and others (victim), and justifications for the emotions attributed to the self. Children were also presented with two hypothetical scenarios of moral transgressions. They had to morally judge these transgressions, justify their judgments, attribute emotions to both perpetrator and victim, and justify the emotions attributed to the perpetrator. Narratives were content analysed (Cohen's κ = .74). Results revealed distinct patterns for real-life and hypothetical transgressions: 9-year-old girls attributed more fear to the perpetrator than 9-year old boys in the hypothetical context, whereas no differences were found in the real-life context. Children gave more moral, sanction-oriented, legitimate, hedonistic, and undifferentiated justifications for hypothetical transgressions. Hypothetical transgressions were judged as more severe than real-life transgressions and were given more moral justifications (by older children) and more undifferentiated justifications (by younger children). In contrast, real-life transgressions were more often presented as justified or legitimate, and moral judgments were more often justified by proposing an alternative strategy. The data of the three studies indicate that although children understand the validity of moral rules, they do not necessarily understand the emotional consequences of following or breaking them. This is especially true for at-risk and physically aggressive children. Accordingly, we argue that immoral conduct is, in part, related to this deficit regarding moral emotions. Therefore it is important to systematically introduce a wide range of moral emotions into educational practice. Studying how moral emotions can serve as motives for (im)moral action tendencies is not only conceptually significant to developmental researchers, but also of practical importance to educators, in particular to teachers. Before establishing educational programs on moral learning in school settings we need to know more about the underlying developmental mechanisms. By studying specific real-life conflict situations and the emotions invoked in the child, teachers can help inculcate sociomoral sensitivity. Sensitizing educators to the variety of interventions they can use in specific situations is a key to stimulating children's moral growth