The Collective Benefits of Feeling Good and Letting Go: Positive Emotion and (dis)Inhibition Interact to Predict Cooperative Behavior

Cooperation is central to human existence, forming the bedrock of everyday social relationships and larger societal structures. Thus, understanding the psychological underpinnings of cooperation is of both scientific and practical importance. Recent work using a dual-process framework suggests that intuitive processing can promote cooperation while deliberative processing can undermine it. Here we add to this line of research by more specifically identifying deliberative and intuitive processes that affect cooperation. To do so, we applied automated text analysis using the Linguistic Inquiry and Word Count (LIWC) software to investigate the association between behavior in one-shot anonymous economic cooperation games and the presence inhibition (a deliberative process) and positive emotion (an intuitive process) in free-response narratives written after (Study 1, N = 4,218) or during (Study 2, N = 236) the decision-making process. Consistent with previous results, across both studies inhibition predicted reduced cooperation while positive emotion predicted increased cooperation (even when controlling for negative emotion). Importantly, there was a significant interaction between positive emotion and inhibition, such that the most cooperative individuals had high positive emotion and low inhibition. This suggests that inhibition (i.e., reflective or deliberative processing) may undermine cooperative behavior by suppressing the prosocial effects of positive emotion.     

Delayed Wound Healing in Heat Stable Antigen (HSA/CD24)-Deficient Mice

Background

Healthy individuals rarely have problems with wound healing. Most skin lesions heal rapidly and efficiently within one to two weeks. However, many medical and surgical complications can be attributed to deficiencies in wound repair. Open wounds have lost the barrier that protects tissues from bacterial invasion and allows the escape of vital fluids. Without expeditious healing, infections become more frequent. The CD24 gene encodes a heavily-glycosylated cell surface protein anchored to the membrane by phosphatidylinositol. CD24 plays an important role in the adaptive immune response and controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. We have previously shown that overexpression of CD24 results in increased proliferation and migration rates.

Aim

To examine the role of CD24 in the wound healing process.

Methods

An excisional model of wound healing was used and delayed wound healing was studied in genetically modified heat stable antigen (HSA/CD24)-deficient mice (HSA ^-/-) compared to wild-type (WT) mice.

Results

Large full-thickness skin wounds, excised on the back of mice, exhibited a significant delay in the formation of granulation tissue, and in wound closure when compared to their WTHSA ^+/+ littermates. Wounds were histologically analyzed and scored, based on the degree of cellular invasion, granulation tissue formation, vascularity, and re-epithelialization. Additionally, in stitched wounds, the HSA ^-/- mice failed to maintain their stitches; they did not hold and fell already 24 hours, revealing erythematous wound fields. Re-expression of HSA, delivered by lentivirus, restored the normal healing phenotype, within 24 hours post-injury, and even improved the healing in WT, and in BalbC mice.

Conclusions

Delayed wound-healing in the absence of HSA/CD24 suggests that CD24 plays an important role in this process. Increased expression of CD24, even in the normal state, may be used to enhance wound repair.     

Currency value moderates equity preference among young children

Cooperative behavior depends in part on a preference for equitable outcomes. Recent research in behavioral economics assesses variables that influence adult concerns for equity, but few studies to date investigate the emergence of equitable behavior in children using similar economic games. We tested 288 3- to 6-year olds in an anonymous Dictator Game to assess how the value of the currency used affects equity preferences in children. To manipulate value, children played the game with their most or least favorite stickers. At all ages, we found a strong value effect with children donating more of their least favorite stickers than their favorite stickers. We also found a dramatic increase with age in the percentage of children who were prosocial (i.e. donated at least one sticker). However, children who were prosocial tended to give the same proportion of stickers at all ages – about half of their least favorite stickers and 40% of their favorite stickers. These findings highlight the influence of resource value on children's preference for equity, and provide evidence for two different processes underlying altruistic giving: the decision to donate at all and the decision about how much to donate.     

Infectious disease modeling of social contagion in networks

Many behavioral phenomena have been found to spread interpersonally through social networks, in a manner similar to infectious diseases. An important difference between social contagion and traditional infectious diseases, however, is that behavioral phenomena can be acquired by non-social mechanisms as well as through social transmission. We introduce a novel theoretical framework for studying these phenomena (the SISa model) by adapting a classic disease model to include the possibility for 'automatic' (or 'spontaneous') non-social infection. We provide an example of the use of this framework by examining the spread of obesity in the Framingham Heart Study Network. The interaction assumptions of the model are validated using longitudinal network transmission data. We find that the current rate of becoming obese is 2 per year and increases by 0.5 percentage points for each obese social contact. The rate of recovering from obesity is 4 per year, and does not depend on the number of non-obese contacts. The model predicts a long-term obesity prevalence of approximately 42, and can be used to evaluate the effect of different interventions on steady-state obesity. Model predictions quantitatively reproduce the actual historical time course for the prevalence of obesity. We find that since the 1970s, the rate of recovery from obesity has remained relatively constant, while the rates of both spontaneous infection and transmission have steadily increased over time. This suggests that the obesity epidemic may be driven by increasing rates of becoming obese, both spontaneously and transmissively, rather than by decreasing rates of losing weight. A key feature of the SISa model is its ability to characterize the relative importance of social transmission by quantitatively comparing rates of spontaneous versus contagious infection. It provides a theoretical framework for studying the interpersonal spread of any state that may also arise spontaneously, such as emotions, behaviors, health states, ideas or diseases with reservoirs.     

Acoustic Competition in Physalaemus pustulosus, a Differential Response to Calls of Relative Frequency

The response of the male túngara frog ( Physalaemus pustulosus ) to conspecific whines of different frequencies was examined. In the first series of playback experiments (fixed frequency), three types of synthetic stimuli were used, corresponding to calls of high frequency (HFF; x + 2 SD), mid-frequency (MFF; x ), and low frequency (LFF; x − 2 SD) for the study population. In the second series of interactive playback experiments (relative frequency), whines of frequency relative to that of the male subject were used: male frequency + 2 SD (HRF), male frequency (MRF), and male frequency −2 SD (LRF). In the fixed frequency experiments, male vocal response did not vary among treatments. However, in the relative frequency experiments, males responded with more whines, and above all, with more chucks, to stimuli of similar or higher frequency than to stimuli of lower frequency than their own. In other words, male vocal competition escalates when competitors have whines with similar or relatively higher frequencies to their own, but does not increase when competitors have call frequencies that are at the mean or higher for the population. This differential response might result from competition between males of different sizes, since the frequency of the whine and male size is significantly correlated.     

Molecular basis of synaptic vesicle cargo recognition by the endocytic sorting adaptor stonin 2

Synaptic transmission depends on clathrin-mediated recycling of synaptic vesicles (SVs). How select SV proteins are targeted for internalization has remained elusive. Stonins are evolutionarily conserved adaptors dedicated to endocytic sorting of the SV protein synaptotagmin. Our data identify the molecular determinants for recognition of synaptotagmin by stonin 2 or its Caenorhabditis elegans orthologue UNC-41B. The interaction involves the direct association of clusters of basic residues on the surface of the cytoplasmic domain of synaptotagmin 1 and a β strand within the μ–homology domain of stonin 2. Mutation of K783, Y784, and E785 to alanine within this stonin 2 β strand results in failure of the mutant stonin protein to associate with synaptotagmin, to accumulate at synapses, and to facilitate synaptotagmin internalization. Synaptotagmin-binding–defective UNC-41B is unable to rescue paralysis in C. elegans stonin mutant animals, suggesting that the mechanism of stonin-mediated SV cargo recognition is conserved from worms to mammals.     

Vg1 RNA localization in oocytes in the absence of xVICKZ3 RNA-binding activity

Vg 1 RNA becomes localized at the vegetal cortex of Xenopus oocytes in a process requiring both intact microtubules (MT) and microfilaments. This localization occurs during a narrow window of oogenesis, when a number of RNA-binding proteins associate with the RNA. xVICKZ3 (Vg1 RBP/Vera), the first Vg1 RNA-binding protein identified, helps mediate the association of Vg1 RNA with MT and is co-localized with the RNA at the vegetal cortex. Given the complexity of the Vg1 RNA ribonucleoprotein (RNP) complex, it has remained unclear how xVICKZ3 functions in Vg1 RNA localization. Here, we have taken a closer look at the process of xVICKZ3 localization in oocytes. We have made use of deletion constructs to perform a structure-function analysis of xVICKZ3. The ability of xVICKZ3-GFP constructs to vegetally localize correlates with their association to MT but not with Vg1 RNA-binding ability. We find that when the ability of xVICKZ3 to bind Vg1 RNA is inhibited by the injection of a construct that dominantly inhibits RNA binding, both the construct and Vg1 RNA still localize, apparently through their continued association with a Vg1 RNA-containing RNP complex. These results emphasize the importance of protein-protein interactions in both xVICKZ3 and Vg1 RNA localization.     

Bayesian inference for dynamic transcriptional regulation; the Hes1 system as a case study

MOTIVATION: In this study, we address the problem of estimating the parameters of regulatory networks and provide the first application of Markov chain Monte Carlo (MCMC) methods to experimental data. As a case study, we consider a stochastic model of the Hes1 system expressed in terms of stochastic differential equations (SDEs) to which rigorous likelihood methods of inference can be applied. When fitting continuous-time stochastic models to discretely observed time series the lengths of the sampling intervals are important, and much of our study addresses the problem when the data are sparse. RESULTS: We estimate the parameters of an autoregulatory network providing results both for simulated and real experimental data from the Hes1 system. We develop an estimation algorithm using MCMC techniques which are flexible enough to allow for the imputation of latent data on a finer time scale and the presence of prior information about parameters which may be informed from other experiments as well as additional measurement error.     

Induction of karyopherin α1 expression by indole-3-acetic acid in auxin-treated or overproducing tobacco plants

Macromolecules may transfer between the cytoplasm and the nucleus only through specific gates—the nuclear pore complexes (NPCs). Translocation of nucleic acids and large proteins requires the presence of a nuclear localization signal (NLS) within the transported molecule. This NLS is recognized by a class of soluble transport receptors termed karyopherins α and β. We previously characterized the expression pattern of the tomato karyopherin α1 (LeKAPα1) promoter in transformed tobacco plants. Expression of LeKAPα1 was mainly observed in growing tissues where cell division and extension is rapid. The expression pattern of LeKAPα1 resembled that of auxin-responsive genes. This led us to suggest that auxin participates in the regulation of LeKAPα1 expression. Here we characterized the correlation between auxin level and the activity of the LeKAPα1 promoter. To this end, transgenic tobacco plants carrying the GUS reporter gene under the control of the LeKAPα1 promoter were treated with various levels of exogenous auxin. We also studied transgenic plants in which we increased the endogenous levels of auxin. For this, we expressed in plants both the LeKAPα1 promoter-GUS reporter and the Agrobacterium tumefaciens iaaM gene, which increases the endogenous levels of auxin. The results indicate that the auxin indole-3-acetic acid (IAA) can induce LeKAPα1 expression. We also identified that the sites and levels of LeKAPα1 expression correlated with the endogenous pathways of polar auxin transport.Key words: auxin, karyopherin α1, nuclear pore complex, TYLCV, plant virus