Avoidance memory requires CaMKII activity to persist after recall

Avoidance memory is destabilized when recalled concurrently with conflicting information, and must undergo a hippocampus-dependent restabilization process called reconsolidation to persist. CaMKII is a serine/threonine protein kinase essential for memory processing; however, its possible involvement in avoidance memory reconsolidation has not yet been studied. Using pharmacological, electrophysiological and optogenetic tools, we found that in adult male Wistar rats hippocampal CaMKII is necessary to reconsolidate avoidance memory, but not to keep it stored while inactive, and that blocking reconsolidation via CaMKII inhibition erases learned avoidance responses.

Monoseeding Increases Peanut (Arachis hypogaea L.) Yield by Regulating Shade-Avoidance Responses and Population Density

We aimed to elucidate the possible yield-increasing mechanisms through regulation of shade-avoidance responses at both physiological and molecular levels under monoseeding. Our results revealed that monoseeding decreased the main stem height but increased the main stem diameter and the number of branches and nodes compared to the traditional double- and triple-seeding patterns. The chlorophyll contents were higher under monoseeding than that under double- and triple-seeding. Further analysis showed that this, in turn, increased the net photosynthetic rate and reallocated higher levels of assimilates to organs. Monoseeding induced the expression patterns of Phytochrome B (Phy B) gene but decreased the expression levels of Phytochrome A (Phy A) gene. Furthermore, the bHLH transcription factors (PIF 1 and PIF 4) that interact with the phytochromes were also decreased under monoseeding. The changes in the expression levels of these genes may regulate the shade-avoidance responses under monoseeding. In addition, monoseeding increased pod yield at the same population density through increasing the number of pods per plant and 100-pod weight than double- and triple-seeding patterns. Thus, we inferred that monoseeding is involved in the regulation of shade-avoidance responsive genes and reallocating assimilates at the same population density, which in turn increased the pod yield.

Ubiquitin-specific proteases UBP12 and UBP13 promote shade avoidance response by enhancing PIF7 stability

Changes in light quality caused by the presence of neighbor proximity regulate many growth and development processes of plants. PHYTOCHROME INTERACTING FACTOR 7 (PIF7), whose subcellular localization, DNA-binding properties, and protein abundance are regulated in a photoreversible manner, plays a central role in linking shade light perception and growth responses. How PIF7 activity is regulated during shade avoidance responses has been well studied, and many factors involved in this process have been identified. However, the detailed molecular mechanism by which shade light regulates the PIF7 protein level is still largely unknown. Here, we show that the PIF7 protein level regulation is important for shade-induced growth. Two ubiquitin-specific proteases, UBP12 and UBP13, were identified as positive regulators in shade avoidance responses by increasing the PIF7 protein level. The ubp12-2w/13–3 double mutant displayed significantly impaired sensitivity to shade-induced cell elongation and reproduction acceleration. Our genetic and biochemical analysis showed that UBP12 and UBP13 act downstream of phyB and directly interact with PIF7 to maintain PIF7 stability and abundance through deubiquitination.

Phytochrome contributes to blue-light-mediated stem elongation and flower initiation in mature Arabidopsis thaliana plants

To examine whether phytochromes contribute to blue-light-mediated stem elongation, plant phenotypic responses were investigated in wild type Arabidopsis thaliana (Col-0), and its quintuple phytochrome (phyA phyB phyC phyD phyE) mutant plants under the following light treatments: (1) R, a pure red light from 660-nm LED; (2) B, a pure blue light from 455-nm LED; (3) BR, a impure blue light from LED combination of 94% B and 6% R; and (4) BRF, another impure blue light from LED combination of BR and 6 µmol m−2 s−1 of FR (735 nm). A photosynthetic photon flux density of ≈100 μmol m−2 s−1 was provided for all the light treatments. The calculated phytochrome photoequilibrium was 0.89, 0.50, 0.69, and 0.60 for R, B, BR, and BRF, respectively, indicating a higher phytochrome activity under R and BR than B and BRF. After 18 days of light treatment, B or BRF increased main stem length in wild-type plants compared with R, but BR had an inhibition effect similar to R. Also, B and BRF relative to R or BR induced earlier flowering and reduced leaf size in wild type plants, showing typical shade-avoidance responses. In phytochrome-deficient mutant plants, the above shade-avoidance responses were inhibited under B or BRF. However, hypocotyl length, a growth trait characterizing the de-etiolation stage, was reduced under B, BR and BRF vs. R regardless of phytochrome absence. These findings suggest that for mature Arabidopsis plants, phytochrome plays a role in blue-light-mediated stem elongation and the associated shade-avoidance responses.

Changes in the Movement and Calling Behavior of Minke Whales (Balaenoptera acutorostrata) in Response to Navy Training

Many marine mammals rely on sound for foraging, maintaining group cohesion, navigation, finding mates, and avoiding predators. These behaviors are potentially disrupted by anthropogenic noise. Behavioral responses to sonar have been observed in a number of baleen whale species but relatively little is known about the responses of minke whales (Balaenoptera acutorostrata). Previous analyses demonstrated a spatial redistribution of localizations derived from passive acoustic detections in response to sonar activity, but the lack of a mechanism for associating localizations prevented discriminating between movement and cessation of calling as possible explanations for this redistribution. Here we extend previous analyses by including an association mechanism, allowing us to differentiate between movement responses and calling responses, and to provide direct evidence of horizontal avoidance responses by individual minke whales to sonar during U.S. Navy training activities. We fitted hidden Markov models to 627 tracks that were reconstructed from 3 years of minke whale (B. acutorostrata) vocalizations recorded before, during, and after naval training events at the U.S. Navy’s Pacific Missile Range Facility, Kauai, Hawaii. The fitted models were used to identify different movement behaviors and to investigate the effect of sonar activity on these behaviors. Movement was faster and more directed during sonar exposure than in baseline phases. The mean direction of movement differed during sonar exposure, and was consistent with movement away from sonar-producing ships. Animals were also more likely to cease calling during sonar. There was substantial individual variation in response. Our findings add large-sample support to previous demonstrations of horizontal avoidance responses by individual minke whales to sonar in controlled exposure experiments, and demonstrate the complex nature of behavioral responses to sonar activity: some, but not all, whales exhibited behavioral changes, which took the form of horizontal avoidance or ceasing to call.

Overgeneralization of fear, but not avoidance, following acute stress

Research has demonstrated the spreading of fear from threat-related stimuli to perceptually similar, but innocuous, stimuli. Less is known, however, about the generalization of avoidance behavior. Given that stress is known to affect learning and memory, we were interested in the effect of acute stress on (over)generalization of fear and avoidance responses. On the first day, one geometrical shape was paired with a mild electrical stimulus (CS+), whereas another shape was not (CS-). One day later, after participants had been exposed to the Maastricht Acute Stress Test or a control task, generalization of avoidance responses and fear (shock expectancy and skin conductance responses) was tested to a range of perceptual generalization stimuli. Generalization gradients were observed across different outcome measures. Stress enhanced generalization of shock expectancy to the stimulus most similar to the CS+. Our findings confirm that stress can affect the generalization of fear, but further studies are warranted.

Determinants of Residents’ Approach–Avoidance Responses to the Personal Carbon Trading Scheme: An Empirical Analysis of Urban Residents in Eastern China

The personal carbon trading (PCT) scheme is a policy instrument for reducing downstream carbon emissions and creating a green lifestyle, and a bottleneck hampering its implementation is the behavioral willingness of residents. Due to a pre-existing stimulus-response association, the willingness of residents can be intuitively reflected by their approach–avoidance responses. This study theoretically analyzed the mechanisms for influencing residents’ approach–avoidance responses towards the personal carbon trading scheme based on open-ended interviews, and empirically examined the mechanisms by developing rating scales and conducting questionnaire surveys on urban residents in eastern China. Findings showed that residents’ approach–avoidance responses could be negatively affected by their preference for comfort, whereas they were positively impacted by their ecological values, sense of social responsibility, cognition of the behaviors for carbon emission reduction, and cognition of personal carbon trading. In terms of subjective norms, the culture of environmentalism had a positive effect on residents’ responses to PCT scheme, while the culture of consumerism caused a negative impact on their responses. Furthermore, the perceived behavioral controls of residents partially mediated the relationships between their psychological characteristics and approach–avoidance responses. Finally, primary and pivotal suggestions were proposed for nudging Chinese urban residents towards approaching the personal carbon trading scheme, which provide theoretical support and practical guidance for its implementation.