No Evidence of the Ego-Depletion Effect across Task Characteristics and Individual Differences: A Pre-Registered Study

Ego-depletion, a psychological phenomenon in which participants are less able to engage in self-control after prior exertion of self-control, has become widely popular in the scientific community as well as in the media. However, considerable debate exists among researchers as to the nature of the ego-depletion effect, and growing evidence suggests the effect may not be as strong or robust as the extant literature suggests. We examined the robustness of the ego-depletion effect and aimed to maximize the likelihood of detecting the effect by using one of the most widely used depletion tasks (video-viewing attention control task) and by considering task characteristics and individual differences that potentially moderate the effect. We also sought to make our research plan transparent by pre-registering our hypotheses, procedure, and planned analyses prior to data collection. Contrary to the ego-depletion hypothesis, participants in the depletion condition did not perform worse than control participants on the subsequent self-control task, even after considering moderator variables. These findings add to a growing body of evidence suggesting ego-depletion is not a reliable phenomenon, though more research is needed that uses large sample sizes, considers moderator variables, and pre-registers prior to data collection.     

Pneumococci induced TLR- and Rac1-dependent NF-kappaB-recruitment to the IL-8 promoter in lung epithelial cells

Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia. The respiratory epithelium constitutes the first line of defense against invading lung pathogens, including pneumococci. We analyzed the involvement of Toll-like receptors (TLR) and Rho-GTPase signaling in the activation of human lung epithelial cells by pneumococci. S. pneumoniae induced release of interleukin-8 (IL-8) by human bronchial epithelial cell line BEAS-2B. Specific inhibition of Rac1 by Nsc23766 or a dominant-negative mutant of Rac1 strongly reduced cytokine release. In addition, pneumococci-related cell activation (IL-8 release, NF-kappaB-activation) depended on MyD88, phosphatidylinositol 3-kinase, and Cdc42 but not on RhoA. Pneumococci enhanced TLR1 and TLR2 mRNA expression in BEAS-2B cells, whereas TLR4 and TLR6 expression was constitutively high. TLR1 and 2 synergistically recognized pneumococci in cotransfection experiments. TLR4, TLR6, LPS-binding protein, and CD14 seem not to be involved in pneumococci-dependent cell activation. At the IL-8 gene promoter, recruitment of phosphorylated NF-kappaB subunit p65 was blocked by inhibition of Rac1, whereas binding of the phosphorylated activator protein-1 subunit c-Jun to the promoter was not diminished. In summary, these results suggest that S. pneumoniae activate human epithelial cells by TLR1/2 and a phosphatidylinositol 3-kinase- and Rac1-dependent NF-kappaB-recruitment to the IL-8 promoter.     

Photochemical processes, carbon assimilation and RNA accumulation of sucrose transporter genes in tomato arbuscular mycorrhiza

Arbuscular mycorrhizal fungi enhance CO₂ assimilation of their hosts which ensure the demand for carbohydrates of these obligate biotrophic microorganisms. Photosynthetic parameters were measured in tomato colonised or not by the arbuscular mycorrhizal fungus Glomus mosseae. In addition, carbohydrate contents and mRNA accumulation of three sucrose transporter genes were analysed. Mycorrhizal plants showed increased opening of stomata and assimilated significant more CO₂. A higher proportion of the absorbed light was used for photochemical processes, while non-photochemical quenching and the content of photoprotective pigments were lower. Analysis of sugar contents showed no significant differences in leaves but enhanced levels of sucrose and fructose in roots, while glucose amounts stayed constant. The three sucrose transporter encoding genes of tomato SlSUT1, SlSUT2 and SlSUT4 were up-regulated providing transport capacities to transfer sucrose into the roots. It is proposed that a significant proportion of sugars is used by the mycorrhizal fungus, because only amounts of fructose were increased, while levels of glucose, which is mainly transferred towards the fungus, were nearly constant.     

The jamming avoidance response in gymnotoid pulse-species: A mechanism to minimize the probability of pulse-train coincidence

Summary Gymnotoid electric fish with pulse-type electric organ discharges (EODs) shorten (lengthen) their EOD intervals as pulses of a slightly slower (faster) train scan their EODs (Figs. 1, 2). They thus minimize the chance of pulse coincidence by transient accelerations (decelerations) of their EOD rate.Studies in curarized preparations demonstrate that this Jamming Avoidance Response (JAR) is controlled by electroreceptive input alone and without reference to an internal electric organ pacemaker-related signal (Fig. 8). A sufficient stimulus input consists of a train of strong, EOD-like stimulus pulses (S₁), which mimic the animal's experience of its own EOD, and a train of small pulses (S₂) of slightly different repetition rate, which mimic EODs of a neighbor. Correct behavioral responses require S₁ pulses of sufficient intensity to recruit pulse-markertype receptors; also spatial and temporal patterns must closely resemble those of the animal's EOD. These features are of little significance for S₂ pulses which, while scanning S₁ pulses, only provide a small perturbation of electroreceptive feedback from S₁ pulses. Inappropriate S₁ stimulation impairs and sometimes reverses (Fig. 7) the behavioral discrimination of scan directions. The JAR is explained in terms of excitatory and inhibitory processes (Fig. 3) which are triggered by S₂ stimulation, at specific phases within the S₁ cycle (Figs. 4–6).The JAR in pulse species strongly resembles the JAR in wave-species (Bullock et al., 1972) and could be considered an evolutionary ancestor of the latter. It is a response to a particular novelty in electroreceptive feedback.We thank Drs. T.H. Bullock, C. Hopkins and an anonymous referee for most helpful criticism. This research was supported by NSF grand BMS74-18640 and NIMH grant PHSMH-2614901 to W.H. and NIH grant/ROI NS 12337-01 to J.B.     

Renal Transplant Recipients Treated with Calcineurin-Inhibitors Lack Circulating Immature Transitional CD19+CD24hiCD38hi Regulatory B-Lymphocytes

BackgroundCD19⁺CD24^hiCD38^hi transitional immature B-lymphocytes have been demonstrated to play an important role in regulating the alloimmune response in transplant recipients. Here, we analyzed the effect of calcineurin inhibition on these peripherally circulating regulatory B-cells (Breg) in renal transplant recipients receiving cyclosporine A (CsA) or tacrolimus.MethodsPBMCs from healthy subjects (HS) (n = 16) and renal transplant recipients (n = 46) were isolated. Flow cytometry was performed for CD19, CD24, CD38 and IL-10 either after isolation or after 72 hours of co-culture in presence of PMA/Ionomycin and TLR9-ligand in presence or absence of increasing concentrations of tacrolimus or CsA.ResultsThe amount of CD19⁺ B-cells among lymphocytes was ∼9.1% in HS, ∼3.6% in CsA (n = 11, p<0.05) and ∼6.4% in TAC (n = 35, p<0.05) treated patients. Among B-cells, a distinct subset of Breg was found to be 4.7% in HS, 1.4% in tacrolimus treated patients and almost blunted in patients receiving CsA. Similarily, ∼4% of B-cells in HS and even fewer in CsA or tacrolimus treated patients produced IL-10 (0.5% and 1.5%, p<0.05) and this was confirmed both in non-transplanted CsA-treated healthy subjects and in in vitro co-culture experiments. Among 29 patients with <1% of Breg, 9 cases (31%) displayed an allograft rejection in contrast to only one case of rejection (6%) among 17 patients with >1%.ConclusionCalcineurin inhibitors reduce number and IL-10 production of Bregs in the peripheral circulation of both renal transplant recipients and non-transplanted healthy subjects. CNI induced Breg reduction is not restricted to a solid organ transplant setting and is not mediated by co-medication with steroids or MPA. A low proportion of Breg cells is associated with an elevated frequency of allograft rejection events.     

SPINE: a method for the rapid detection and analysis of protein-protein interactions in vivo

The detection and analysis of protein-protein interactions is one of the central tasks of proteomics in the postgenomic era. For this purpose, we present a procedure, the Strep-protein interaction experiment (SPINE) that combines the advantages of the Strep-tag protein purification system with those of reversible in vivo protein crosslinking by formaldehyde. Using two Bacillus subtilis regulator proteins, we demonstrate that this method is well suited to isolate protein complexes with high purity and virtually no background. Plasmids allowing the high-level expression of proteins carrying an N- or C-terminal Strep-tag in B. subtilis were constructed.     

The physiology and morphology of two types of electrosensory neurons in the weakly electric fishApteronotus leptorhynchus

Summary Previous anatomical and physiological studies of the gymnotoid electrosensory lateral line lobe (ELLL) suggest that the anatomically identified basilar and non-basilar pyramidal cells correspond to the physiologically defined E and I cells. Intracellular injection of horseradish peroxidase (HRP) into physiologically identified E and I cells confirms this hypothesis. The morphologies and physiological responses of the basilar and non-basilar pyramidal cells were compared. Both types of pyramidal cells have extensive apical dendritic trees that interact with a parallel fiber network in the ELLL. The apical dendritic trees of the non-basilar pyramidal cells have a wider spread along the rostrocaudal axis of the ELLL than those of the basilar pyramidal cells. This difference is discussed in reference to the interaction of these cell types with the parallel fibers of the ELLL. The density of apical dendritic branches was measured and related to the distance of these branches from the cell body. No obvious differences were seen between the dendritic density patterns of basilar and non-basilar pyramidal cells. An interesting correlation, however, exists between the atypical physiological characteristics of two basilar pyramidal cells and their dendritic density patterns. Two cells of the medial (ampullary) segment of the ELLL were analyzed. Like the pyramidal cells of the three lateral (tuberous) regions of the ELLL, the physiology of these cells appears to be related to the presence of an extended basilar process. The ampullary cells, however, have apical dendritic trees that are oriented orthogonally to the dendritic trees of the pyramidal cells.Abbreviations AM amplitude modulation - DML dorsal molecular layer - ELLL electrosensory lateral line lobe - EOD electric organ discharge - HRP horseradish peroxidase - LC lobus caudalis - Npd nucleus praeeminentialis dorsalis - PSTH post stimulus time histogram