Highlights • OC intake leads to a blunted cortisol increase after the SECPT. • Pre-encoding stress enhances cued recall of negative words in men. • Pre-encoding stress seems to increase cued recall ...of neutral words in OC women. • Pre-encoding stress does not influence cued recall in free-cycling women. • Pre-encoding stress does not influence free recall in general.
•Originates from discussions on replicability and researcher’s degrees of freedom.•Aims at stimulating discussions on methods applied in fear conditioning research.•Addresses critical issues on ...terminology, design, methods, analysis.•Serves as comprehensive compendium and critical evaluation of read-out measures.•Highlights methodological considerations when studying individual differences.
The so-called ‘replicability crisis’ has sparked methodological discussions in many areas of science in general, and in psychology in particular. This has led to recent endeavours to promote the transparency, rigour, and ultimately, replicability of research. Originating from this zeitgeist, the challenge to discuss critical issues on terminology, design, methods, and analysis considerations in fear conditioning research is taken up by this work, which involved representatives from fourteen of the major human fear conditioning laboratories in Europe.
This compendium is intended to provide a basis for the development of a common procedural and terminology framework for the field of human fear conditioning. Whenever possible, we give general recommendations. When this is not feasible, we provide evidence-based guidance for methodological decisions on study design, outcome measures, and analyses. Importantly, this work is also intended to raise awareness and initiate discussions on crucial questions with respect to data collection, processing, statistical analyses, the impact of subtle procedural changes, and data reporting specifically tailored to the research on fear conditioning.
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins catalyze membrane fusion events in the secretory and endolysosomal systems, and all SNARE-mediated fusion ...processes require cofactors of the Sec1/Munc18 (SM) family. Vps33 is an SM protein and subunit of the Vps-C complexes HOPS (homotypic fusion and protein sorting) and CORVET (class C core vacuole/endosome tethering), which are central regulators of endocytic traffic. Here we present biochemical studies of interactions between Saccharomyces cerevisiae vacuolar SNAREs and the HOPS holocomplex or Vps33 alone. HOPS binds the N-terminal H(abc) domain of the Qa-family SNARE Vam3, but Vps33 is not required for this interaction. Instead, Vps33 binds the SNARE domains of Vam3, Vam7, and Nyv1. Vps33 directly binds vacuolar quaternary SNARE complexes, and the affinity of Vps33 for SNARE complexes is greater than for individual SNAREs. Through targeted mutational analyses, we identify missense mutations of Vps33 that produce a novel set of defects, including cargo missorting and the loss of Vps33-HOPS association. Together these data suggest a working model for membrane docking: HOPS associates with N-terminal domains of Vam3 and Vam7 through Vps33-independent interactions, which are followed by binding of Vps33, the HOPS SM protein, to SNARE domains and finally to the quaternary SNARE complex. Our results also strengthen the hypothesis that SNARE complex binding is a core attribute of SM protein function.
Abstract
The presence of both inversion (
P
) and time-reversal (
T
) symmetries in solids leads to a double degeneracy of the electronic bands (Kramers degeneracy). By lifting the degeneracy, spin ...textures manifest themselves in momentum space, as in topological insulators or in strong Rashba materials. The existence of spin textures with Kramers degeneracy, however, is difficult to observe directly. Here, we use quantum interference measurements to provide evidence for the existence of hidden entanglement between spin and momentum in the antiperovskite-type Dirac material Sr
3
SnO. We find robust weak antilocalization (WAL) independent of the position of
E
F
. The observed WAL is fitted using a single interference channel at low doping, which implies that the different Dirac valleys are mixed by disorder. Notably, this mixing does not suppress WAL, suggesting contrasting interference physics compared to graphene. We identify scattering among axially spin-momentum locked states as a key process that leads to a spin-orbital entanglement.
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•Surface activity of α-lactalbumin > β‑lactoglobulin > trypsinogen > papain.•Average hydrophobicity of proteins not significantly different from each other.•Hydrophobins are totally ...different in hydrophobicity and amphilicity from each other.•Occurrence of highly amphiphilic structures alone does not explain surface activity.•Other macroscopic protein properties, like the MGS, are related to surface activity.
Their surface activity enables proteins to form and stabilize foam, which can be used for in situ product separation or foam fractionation. Thus, it would be highly desirable to predict the surface activity of proteins based on their molecular properties like hydrophobicity, amphilicity, or structure on primary, secondary, and tertiary level. Ionic strength and pH were adjusted to gain maximum surface activity. The surface activity decreased in the order α lactalbumin > β‑lactoglobulin > trypsinogen > papain. For the theoretical analysis, the database was extended by including 2 hydrophobins into the investigation, since they are known to exhibit an outstanding surface activity. No relation to the macroscopic behavior was found considering the hydrophobicity. I.e., the non-hydrophobins did not differ significantly from each other, and from the hydrophobins, one was significantly hydrophobic, and the other was significantly hydrophilic. Also, no relations were found considering the amphilicity of the secondary structure elements. However, taking into account the tertiary protein structure, it was found that for most of the proteins investigated, the presence of non-buried amphiphilic secondary structure elements in combination with a certain amount of flexibility correlates with the surface activity.
A general approach is described for the formation of tetrahydrothiepines using donor–acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in ...a Lewis acid catalyzed formal (4 + 3)-cycloaddition reaction with donor–acceptor cyclopropanes as three-atom building blocks. Under mild conditions various tetrahydrothiepines were synthesized in good yields in a stereospecific reaction with high functional group tolerance.
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•High surface activity does not necessarily require secondary structure change.•Initially, most proteins had a native-like secondary structure at the interface.•If a secondary ...structure change occurred, additional β-sheets formed.•The proteins which quickly increased the surface pressure were most surface-active.
A major difference between proteins and surfactants is that proteins are capable of changing their structure during refolding processes in the adsorbed state. It is often reported that these interfacial structure changes increase the surface activity of proteins. In order to investigate this, the surface activity of 5 proteins was determined in foam fractionation experiments, where pH and ionic strength were adjusted separately to gain the maximum surface activity for each protein. Infrared Reflection Absorption Spectroscopy was performed for each protein to analyze the changes in secondary structure after adsorption. In order to investigate quick structural changes, transmission Fourier Transform Infrared spectroscopy was performed to gain information about the secondary structure of the dissolved, non-adsorbed proteins. It was found that most proteins maintain a native-like conformation when adsorbed at the interface. With increasing time, most of the proteins investigated increased the amount of β-sheets at the interface. This slow process went along with a slow increase in surface pressure. A correlation between structural changes on molecular level and surface activity on macroscopic level could not be found. However, the absolute increase of surface pressure at the very beginning of the adsorption process correlated with the surface activity of the proteins, suggesting that the slow processes on molecular level do not have a considerable impact on macroscopic surface activity.
The relevance of contextual factors in shaping neural mechanisms underlying visceral pain-related fear learning remains elusive. However, benign interoceptive sensations, which shape patients’ ...clinical reality, may context-dependently become conditioned predictors of impending visceral pain. In a novel context-dependent interoceptive conditioning paradigm, we elucidated the putative role of the central fear network in the acquisition and extinction of pain-related fear induced by interoceptive cues and pain-predictive contexts.
In this fMRI study involving rectal distensions as a clinically-relevant model of visceroception, N = 27 healthy men and women underwent differential conditioning. During acquisition training, visceral sensations of low intensity as conditioned stimuli (CS) predicted visceral pain as unconditioned stimulus (US) in one context (Con+), or safety from pain in another context (Con–). During extinction training, interoceptive CS remained unpaired in both contexts, which were operationalized as images of different rooms presented in the MRI scanner.
Successful contextual conditioning was supported by increased negative valence of Con+ compared to Con– after acquisition training, which resolved after extinction training. Although interoceptive CS were perceived as comparatively pleasant, they induced significantly greater neural activation of the amygdala, ventromedial PFC, and hippocampus when presented in Con+, while contexts alone did not elicit differential responses. During extinction training, a shift from CS to context differentiation was observed, with enhanced responses in the amygdala, ventromedial, and ventrolateral PFC to Con+ relative to Con–, whereas no CS-induced differential activation emerged.
Context-dependent interoceptive conditioning can turn benign interoceptive cues into predictors of visceral pain that recruit key regions of the fear network. This first evidence expands knowledge about learning and memory mechanisms underlying interoceptive hypervigilance and maladaptive avoidance behavior, with implications for disorders of the gut-brain axis.
Emotion regulation is essential for adaptive behavior and mental health. Strategies applied to alter emotions are known to differ in their impact on psychological and physiological aspects of the ...emotional response. However, emotion regulation outcome has primarily been assessed via self‐report, and studies comparing regulation strategies with regard to their peripheral physiological mechanisms are limited in number. In the present study, we therefore aimed to investigate the effects of different emotion regulation strategies on pupil dilation, skin conductance responses, and subjective emotional responses. Thirty healthy females were presented with negative and neutral pictures and asked to maintain or up‐ and downregulate their upcoming emotional responses through reappraisal or distraction. Pupil dilation and skin conductance responses were significantly enhanced when viewing negative relative to neutral pictures. For the pupil, this emotional arousal effect manifested specifically late during the pupillary response. In accordance with subjective ratings, increasing negative emotions through reappraisal led to the most prominent pupil size enlargements, whereas no consistent effect for downregulation was found. In contrast, early peak dilations were enhanced in all emotion regulation conditions independent of strategy. Skin conductance responses were not further modulated by emotion regulation. These results indicate that pupil diameter is modulated by emotional arousal, but is initially related to the extent of mental effort required to regulate automatic emotional responses. Our data thus provide first evidence that the pupillary response might comprise two distinct temporal components reflecting cognitive emotion regulation effort on the one hand and emotion regulation success on the other hand.
Twitching and social gliding motility allow many Gram negative bacteria
to crawl along surfaces, and are implicated in a wide range of biological
functions. Type IV pili (Tfp) are required for ...twitching and
social gliding, but the mechanism by which these filaments promote motility
has remained enigmatic. Here we use laser tweezers to show that Tfp forcefully retract. Neisseria gonorrhoeae
cells that produce Tfp actively crawl on a glass surface and form adherent
microcolonies. When laser tweezers are used to place and hold cells near a
microcolony, retractile forces pull the cells toward the microcolony. In quantitative
experiments, the Tfp of immobilized bacteria bind to latex beads and retract,
pulling beads from the tweezers at forces that can exceed 80 pN. Episodes
of retraction terminate with release or breakage of the Tfp tether. Both motility
and retraction mediated by Tfp occur at about 1 µm s-1
and require protein synthesis and function of the PilT protein. Our
experiments establish that Tfp filaments retract, generate substantial force
and directly mediate cell movement.
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