Phosphorylation of Phosphoenolpyruvate Carboxylase Is Essential for Maximal and Sustained Dark CO2 Fixation and Core Circadian Clock Operation in the Obligate Crassulacean Acid Metabolism Species Kalanchoe fedtschenkoi

Phosphoenolpyruvate carboxylase (PPC; EC 4.1.1.31) catalyzes primary nocturnal CO2 fixation in Crassulacean acid metabolism (CAM) species. CAM PPC is regulated posttranslationally by a circadian clock-controlled protein kinase called phosphoenolpyruvate carboxylase kinase (PPCK). PPCK phosphorylates PPC during the dark period, reducing its sensitivity to feedback inhibition by malate and thus enhancing nocturnal CO2 fixation to stored malate. Here, we report the generation and characterization of transgenic RNAi lines of the obligate CAM species Kalanchoë fedtschenkoi with reduced levels of KfPPCK1 transcripts. Plants with reduced or no detectable dark phosphorylation of PPC displayed up to a 66% reduction in total dark period CO2 fixation. These perturbations paralleled reduced malate accumulation at dawn and decreased nocturnal starch turnover. Loss of oscillations in the transcript abundance of KfPPCK1 was accompanied by a loss of oscillations in the transcript abundance of many core circadian clock genes, suggesting that perturbing the only known link between CAM and the circadian clock feeds back to perturb the central circadian clock itself. This work shows that clock control of KfPPCK1 prolongs the activity of PPC throughout the dark period in K. fedtschenkoi, optimizing CAM-associated dark CO2 fixation, malate accumulation, CAM productivity, and core circadian clock robustness

Rapid assessment methods for small farm storage surveys

Farm surveys are often the first step taken in identifying storage problems. As time and money for such work are generally scarce, it is important to be able to make the best use of them to get the information needed. This paper describes some of the specific techniques and experience developed by the Ghana MoFA/UK ODA Larger Grain Borer Project for rapid storage surveys on small-scale farms. It is argued that the following factors can critically contribute to producing more timely and relevant results: • formulation of specific survey objectives which focus on gathering data needed for decision-making. • use of a range of techniques to meet these objectives, including secondary data and key informants, informal surveys, case studies and participatory meetings. • avoidance of unwitting sampling bias, using rapid techniques such as transect village walks to select farmers, along with careful timing of field visits. • methods of sample analysis which can be used in the field, rather than the lab. Field analysis has many benefits including cost, speed, potential for increased sampling, and most importantly the greater participation of farmers and field staff in the analysis and interpretation of results. • use of rapid and flexible techniques of analysis and presentation, in particular mapping. Practical examples of each of these are given

When the working day is through: The end of work as identity?

This article seeks to present a counter-case to the ‘end of work thesis’ advocated by writers such as Beck, Sennett and Bauman. It argues that work remains a significant locus of personal identity and that the depiction by these writers of endemic insecurity in the workplace is inaccurate and lacks empirical basis. The article draws upon case study data to illustrate how, across a range of workplaces, work remains an importance source of identity, meaning and social affiliation

Transgressing the moral economy: Wheelerism and management of the nationalised coal industry in Scotland

This article illuminates the links between managerial style and political economy in post-1945 Britain, and explores the origins of the 1984–1985 miners' strike, by examining in longer historical context the abrasive attitudes and policies of Albert Wheeler, Scottish Area Director of the National Coal Board (NCB). Wheeler built on an earlier emphasis on production and economic criteria, and his micro-management reflected pre-existing centralising tendencies in the industries. But he was innovative in one crucial aspect, transgressing the moral economy of the Scottish coalfield, which emphasised the value of economic security and changes by joint industrial agreement

Family-Friendly Management, Organizational Performance and Social Legitimacy

Research on family-friendly practices has concentrated on the predictors of their use, particularly from the perspective of either institutional theory or the high involvement or commitment management vogue. This paper first shows how such perspectives can be used to generate hypotheses about the link between family-friendly management and organizational performance. Second, the paper reports research designed to test these, using data from a national representative sample of workplaces across the British economy, the Workplace Employment Relations Survey of 2004 (WERS2004). The results support the high commitment thesis that family-friendly management will strengthen the relationship between commitment and key economic outcomes, as the relationships between workforce commitment and productivity or quality are stronger in organizations when friendly management is high, which is consistent with social exchange theory. Family-friendly management is not, however, related to the human resource outcomes of labour turnover and absenteeism. Nor does the study find support for the argument that its use in conjunction with high involvement management enhances the performance effects of both. Equally, there is no support for the hypothesis from the institutional thesis that family-friendly management has positive effects on the legitimacy of the organization

Human Resources and the Resource Based View of the Firm

The resource-based view (RBV) of the firm has influenced the field of strategic human resource management (SHRM) in a number of ways. This paper explores the impact of the RBV on the theoretical and empirical development of SHRM. It explores how the fields of strategy and SHRM are beginning to converge around a number of issues, and proposes a number of implications of this convergence

Evolutionary relationships among barley and <i>Arabidopsis</i> core circadian clock and clock-associated genes

The circadian clock regulates a multitude of plant developmental and metabolic processes. In crop species, it contributes significantly to plant performance and productivity and to the adaptation and geographical range over which crops can be grown. To understand the clock in barley and how it relates to the components in the Arabidopsis thaliana clock, we have performed a systematic analysis of core circadian clock and clock-associated genes in barley, Arabidopsis and another eight species including tomato, potato, a range of monocotyledonous species and the moss, Physcomitrella patens. We have identified orthologues and paralogues of Arabidopsis genes which are conserved in all species, monocot/dicot differences, species-specific differences and variation in gene copy number (e.g. gene duplications among the various species). We propose that the common ancestor of barley and Arabidopsis had two-thirds of the key clock components identified in Arabidopsis prior to the separation of the monocot/dicot groups. After this separation, multiple independent gene duplication events took place in both monocot and dicot ancestors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00239-015-9665-0) contains supplementary material, which is available to authorized users

Investigation of the regulation of carbohydrate metabolism in Arabidopsis thaliana using a genetic approach

The regulation of carbohydrate metabolism in Arabidopsis thaliana was investigated using a genetic approach. A new class of carbohydrate insensitive mutant (cai) was characterised in order to gain insight into the control of carbohydrate metabolism. Wild type seedlings germinated on media containing 100 mM sucrose and 0.1 mM nitrogen but their cotyledons did not expand and accumulated anthocyanins. After 1 week growth was arrested. The internal carbohydrate content increased accompanied by repression of photosynthetic genes and induction of chs gene expression, cai mutants germinated on agar media containing 100 mM sucrose and 0.1 mM nitrogen but their cotyledons expanded and greened. After initial characterisation of a number of the mutants, two were selected for further analysis. When germinated on a range of different carbon; nitrogen ratios cai 10 and cai 28 displayed a reduced sensitivity to the high carbohydrate and low nitrogen conditions, cai 10 also displayed a mannose insensitive (mig) phenotype compared to the post-germinative growth of wild type which was arrested by mannose. This growth arrest in the wild type on mannose correlates with phosphate sequestration, cai 10 metabolises mannose at a different rate and accumulates less hexose phosphate than the wild type when germinated on mannose, thus indicating that the mannose insensitive phenotype may be a consequence of a disruption in metabolism. Overexpression of Arabidopsis hexokinase 1 in cai 10 did not complement the cai 10 phenotype. In contrast to previous results by Jang et al., (1997), who found that plants overexpressing hexokinase were hypersensitive to sugars, our results indicate that they are less sensitive than wild type. This is not in agreement with the proposed model of hexokinase as a sugar sensor (Jang et al., 1997). Seeds of the hexokinase overexpressors germinated rapidly (within 18-20 h). The seeds also contained elevated levels of some amino acids, smaller lipid bodies and less lipid than the wild type. It is proposed that hexokinase overexpression increases glucose-6-phosphate concentration which activates phosphoenolpyravate carboxylase (PEPCase) and in so doing diverts carbon from lipid biosynthesis to amino acid synthesis

Quantitative cross-species extrapolation between humans and fish: The case of the anti-depressant fluoxetine

This article has been made available through the Brunel Open Access Publishing Fund.Fish are an important model for the pharmacological and toxicological characterization of human pharmaceuticals in drug discovery, drug safety assessment and environmental toxicology. However, do fish respond to pharmaceuticals as humans do? To address this question, we provide a novel quantitative cross-species extrapolation approach (qCSE) based on the hypothesis that similar plasma concentrations of pharmaceuticals cause comparable target-mediated effects in both humans and fish at similar level of biological organization (Read-Across Hypothesis). To validate this hypothesis, the behavioural effects of the anti-depressant drug fluoxetine on the fish model fathead minnow (Pimephales promelas) were used as test case. Fish were exposed for 28 days to a range of measured water concentrations of fluoxetine (0.1, 1.0, 8.0, 16, 32, 64 μg/L) to produce plasma concentrations below, equal and above the range of Human Therapeutic Plasma Concentrations (HTPCs). Fluoxetine and its metabolite, norfluoxetine, were quantified in the plasma of individual fish and linked to behavioural anxiety-related endpoints. The minimum drug plasma concentrations that elicited anxiolytic responses in fish were above the upper value of the HTPC range, whereas no effects were observed at plasma concentrations below the HTPCs. In vivo metabolism of fluoxetine in humans and fish was similar, and displayed bi-phasic concentration-dependent kinetics driven by the auto-inhibitory dynamics and saturation of the enzymes that convert fluoxetine into norfluoxetine. The sensitivity of fish to fluoxetine was not so dissimilar from that of patients affected by general anxiety disorders. These results represent the first direct evidence of measured internal dose response effect of a pharmaceutical in fish, hence validating the Read-Across hypothesis applied to fluoxetine. Overall, this study demonstrates that the qCSE approach, anchored to internal drug concentrations, is a powerful tool to guide the assessment of the sensitivity of fish to pharmaceuticals, and strengthens the translational power of the cross-species extrapolation