Controlling the Cyanobacterial Clock by Synthetically Rewiring Metabolism

SummaryCircadian clocks are oscillatory systems that allow organisms to anticipate rhythmic changes in the environment. Several studies have shown that circadian clocks are connected to metabolism, but it is not generally clear whether metabolic signaling is one voice among many that influence the clock or whether metabolic cycling is the major clock synchronizer. To address this question in cyanobacteria, we used a synthetic biology approach to make normally autotrophic cells capable of growth on exogenous sugar. This allowed us to manipulate metabolism independently from light and dark. We found that feeding sugar to cultures blocked the clock-resetting effect of a dark pulse. Furthermore, in the absence of light, the clock efficiently synchronizes to metabolic cycles driven by rhythmic feeding. We conclude that metabolic activity, independent of its source, is the primary clock driver in cyanobacteria

Emergence of Zipf's Law in the Evolution of Communication

Zipf's law seems to be ubiquitous in human languages and appears to be a universal property of complex communicating systems. Following the early proposal made by Zipf concerning the presence of a tension between the efforts of speaker and hearer in a communication system, we introduce evolution by means of a variational approach to the problem based on Kullback's Minimum Discrimination of Information Principle. Therefore, using a formalism fully embedded in the framework of information theory, we demonstrate that Zipf's law is the only expected outcome of an evolving, communicative system under a rigorous definition of the communicative tension described by Zipf.Comment: 7 pages, 2 figure

The moderating effects of mindful eating on the relationship between emotional functioning and eating styles in overweight and obese women

The aim of the current study was to examine the moderating effect of mindful eating on the relationship between emotional functioning and eating styles in overweight and obese women. One hundred and eighty four overweight and obese adult women (BMI 30.12\u2009\ub1\u20093.77 kg/m2) were assessed with the Difficulties in Emotion Regulation Scale, the Positive and Negative Affect Schedule, the Three Factor Eating Questionnaire and the Mindful Eating Scale. Mindful eating significantly moderated several of the relationships between emotional functioning and eating styles. When mindful eating techniques are included as part of an intervention for overweight or obese individuals, it is even more important that those interventions should also include techniques to reduce emotion dysregulation and negative affect

Switcher-random-walks: a cognitive-inspired mechanism for network exploration

Semantic memory is the subsystem of human memory that stores knowledge of concepts or meanings, as opposed to life specific experiences. The organization of concepts within semantic memory can be understood as a semantic network, where the concepts (nodes) are associated (linked) to others depending on perceptions, similarities, etc. Lexical access is the complementary part of this system and allows the retrieval of such organized knowledge. While conceptual information is stored under certain underlying organization (and thus gives rise to a specific topology), it is crucial to have an accurate access to any of the information units, e.g. the concepts, for efficiently retrieving semantic information for real-time needings. An example of an information retrieval process occurs in verbal fluency tasks, and it is known to involve two different mechanisms: -clustering-, or generating words within a subcategory, and, when a subcategory is exhausted, -switching- to a new subcategory. We extended this approach to random-walking on a network (clustering) in combination to jumping (switching) to any node with certain probability and derived its analytical expression based on Markov chains. Results show that this dual mechanism contributes to optimize the exploration of different network models in terms of the mean first passage time. Additionally, this cognitive inspired dual mechanism opens a new framework to better understand and evaluate exploration, propagation and transport phenomena in other complex systems where switching-like phenomena are feasible.Comment: 9 pages, 3 figures. Accepted in "International Journal of Bifurcations and Chaos": Special issue on "Modelling and Computation on Complex Networks

Dyadic Predictors of Child Body Shame in a Polish and Italian Sample

The present study aimed at assessing the predictors (related to the functioning of a parent-child dyad) of child body shame. Therefore, in the main analysis we examined relationships among child body shame, child perfectionism, child body dissatisfaction, parent body shame, parent perfectionism, and parent body dissatisfaction. In our main hypothesis we assumed that higher levels of the abovementioned parent functioning-related variables would be associated with higher child body shame after accounting for the effects of the foregoing child functioning-related variables. The analysis finally included complete data from 420 participants, i.e., a 115 Polish and 95 Italian parent-child dyad. Participants completed: (a) child: the Objectified Body Consciousness Scale for Youth, the Child-Adolescent Perfectionism Scale, the Children’s Body Image Scale/the Figure Rating Scale; (b) parent: the Objectified Body Consciousness Scale, the Frost Multidimensional Perfectionism Scale, and the Contour Drawing Rating Scale. The results of a correlational analysis show that in both the Polish and Italian samples, the higher the level of child body shame, the higher the level of the following variables: child perfectionism, child body dissatisfaction, parent perfectionism, and parent body dissatisfaction. Interestingly, the only insignificant relationship in both samples is the association between body shame in both members of the child-parent dyad. Moreover, all steps of the regressions were significant in both Polish and Italian samples. It turned out that only in the Italian sample were all predictors significantly associated with a child’s body shame (in the Polish sample there was no significant association between child’s body shame and parent’s perfectionism). To sum up, the above studies show the importance of considering the functioning of the parent-child dyad in understanding child body shame. These findings suggest that parents’ attitudes toward their bodies and their beliefs about an ideal self should be taken into account when planning interventions to improve children’s and adolescents’ attitudes toward their bodies. This is so because it is possible for children to internalize their parents’ beliefs about how to look and how critical one should be of themselves, which can result in strong body shame when they are not perfect enough against the internalized ideal. Therefore, it is also necessary to make parents aware that children’s attitude toward their body is often a reflection of parents’ attitude toward the body

Plasma proteome profiling of freshwater and seawater life stages of rainbow trout (Oncorhynchus mykiss)

The sea-run phenotype of rainbow trout (Oncorhynchus mykiss), like other anadromous salmonids, present a juvenile stage fully adapted to life in freshwater known as parr. Development in freshwater is followed by the smolt stage, where preadaptations needed for seawater life are developed making fish ready to migrate to the ocean, after which event they become post-smolts. While these three life stages have been studied using a variety of approaches, proteomics has never been used for such purpose. The present study characterised the blood plasma proteome of parr, smolt and post-smolt rainbow trout using a gel electrophoresis liquid chromatography tandem mass spectrometry approach alone or in combination with low-abundant protein enrichment technology (combinatorial peptide ligand library). In total, 1,822 proteins were quantified, 17.95% of them being detected only in plasma post enrichment. Across all life stages, the most abundant proteins were ankyrin-2, DNA primase large subunit, actin, serum albumin, apolipoproteins, hemoglobin subunits, hemopexin-like proteins and complement C3. When comparing the different life stages, 17 proteins involved in mechanisms to cope with hyperosmotic stress and retinal changes, as well as the downregulation of nonessential processes in smolts, were significantly different between parr and smolt samples. On the other hand, 11 proteins related to increased growth in post-smolts, and also related to coping with hyperosmotic stress and to retinal changes, were significantly different between smolt and post-smolt samples. Overall, this study presents a series of proteins with the potential to complement current seawater-readiness assessment tests in rainbow trout, which can be measured non-lethally in an easily accessible biofluid. Furthermore, this study represents a first in-depth characterisation of the rainbow trout blood plasma proteome, having considered three life stages of the fish and used both fractionation alone or in combination with enrichment methods to increase protein detection