scholarly journals To stabilize neutrophil polarity, PIP3 and Cdc42 augment RhoA activity at the back as well as signals at the front

2006 ◽  
Vol 174 (3) ◽  
pp. 437-445 ◽  
Author(s):  
Alexandra Van Keymeulen ◽  
Kit Wong ◽  
Zachary A. Knight ◽  
Cedric Govaerts ◽  
Klaus M. Hahn ◽  
...  

Chemoattractants like f-Met-Leu-Phe (fMLP) induce neutrophils to polarize by triggering divergent signals that promote the formation of protrusive filamentous actin (F-actin; frontness) and RhoA-dependent actomyosin contraction (backness). Frontness locally inhibits backness and vice versa. In neutrophil-like HL60 cells, blocking phosphatidylinositol-3,4,5-tris-phosphate (PIP3) accumulation with selective inhibitors of PIP3 synthesis completely prevents fMLP from activating a PIP3-dependent kinase and Cdc42 but not from stimulating F-actin accumulation. PIP3-deficient cells show reduced fMLP-dependent Rac activity and unstable pseudopods, which is consistent with the established role of PIP3 as a mediator of positive feedback pathways that augment Rac activation at the front. Surprisingly, such cells also show reduced RhoA activation and RhoA-dependent contraction at the trailing edge, leading to the formation of multiple lateral pseudopods. Cdc42 mediates PIP3's positive effect on RhoA activity. Thus, PIP3 and Cdc42 maintain stable polarity with a single front and a single back not only by strengthening pseudopods but also, at longer range, by promoting RhoA-dependent actomyosin contraction at the trailing edge.

2002 ◽  
Vol 158 (7) ◽  
pp. 1219-1228 ◽  
Author(s):  
Gianluca Gallo ◽  
Hal F. Yee ◽  
Paul C. Letourneau

Growth cone motility and guidance depend on the dynamic reorganization of filamentous actin (F-actin). In the growth cone, F-actin undergoes turnover, which is the exchange of actin subunits from existing filaments. However, the function of F-actin turnover is not clear. We used jasplakinolide (jasp), a cell-permeable macrocyclic peptide that inhibits F-actin turnover, to study the role of F-actin turnover in axon extension. Treatment with jasp caused axon retraction, demonstrating that axon extension requires F-actin turnover. The retraction of axons in response to the inhibition of F-actin turnover was dependent on myosin activity and regulated by RhoA and myosin light chain kinase. Significantly, the endogenous myosin-based contractility was sufficient to cause axon retraction, because jasp did not alter myosin activity. Based on these observations, we asked whether guidance cues that cause axon retraction (ephrin-A2) inhibit F-actin turnover. Axon retraction in response to ephrin-A2 correlated with decreased F-actin turnover and required RhoA activity. These observations demonstrate that axon extension depends on an interaction between endogenous myosin-driven contractility and F-actin turnover, and that guidance cues that cause axon retraction inhibit F-actin turnover.


2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.


2019 ◽  
Vol 14 (2) ◽  
pp. 119
Author(s):  
Riza Syahputera ◽  
Martha Rianty

AbstractThis study aims to determine the effect of the role of the Chairperson and Cooperative Manager in the preparation and application of Financial Statements based on SAK ETAP in cooperatives in the city of Palembang. This research is a quantitative study using data obtained from questionnaires and measured using a Likert scale. The sampling technique used is purposive sampling. The sample used in this study was the Chairperson of the cooperative and the manager of the cooperative in the city of Palembang. The cooperatives studied were 203 cooperatives. The data analysis technique used is multiple linear regression test. The results showed that the role of cooperative leaders and managers had a significant positive effect on the preparation and application of SAK ETAP-based financial statements.Keywords : chairman, manager, SAK ETAP, cooperative


2020 ◽  
Author(s):  
Charles Scelles ◽  
LUIS CARLO BULNES

Eye Movement Desensitization and Reprocessing (EMDR) is a treatment for post-traumatic stressdisorder (PTSD). The technique is known to stimulate the capacity to reprocess maladaptive memoriesthat are thought to be central to this pathology. Here we investigate if EMDR therapy can be used in otherconditions than PTSD. We conducted a systematic literature search on PubMed, ScienceDirect, Scopus, and Web of Science. Wesearched for published empirical findings on EMDR, excluding those centred on trauma and PTSD,published up to 2020. The results were classified by psychiatric categories.   Ninety articles met our research criteria. A positive effect was reported in addictions, somatoformdisorders, sexual dysfunction, eating disorder, disorders of adult personality, mood disorders, reaction tosevere stress, anxiety disorders, performance anxiety, Obsessive-Compulsive Disorder (OCD), pain,neurodegenerative disorders, paedopsychiatry and sleep. The evidence was more consistent in pain, OCD,mood disorders, and reaction to severe stress.EMDR’s efficiency across numerous pathological situations, highlighted the central role of affectivememory in several psychiatric and non-psychiatric conditions. Furthermore, EMDR seems to besuccessful in usually uncooperative (e.g. Dementia) or unproductive cases (e.g. aphasia). Moreover, insome severe medical situations were psychologic distress was an obstacle, EMDR allowed thecontinuation of treatment-as-usual. Our review suggests that it is a safe and economical therapeuticoption, and its effect in non-pathological situations opens new avenues for translational research. Overallmore methodologically rigorous studies are needed.


2018 ◽  
Vol 9 (2) ◽  
pp. 18-32
Author(s):  
Andy Mulyana ◽  
Devi Ayuni

This study aims to evaluate the role of satisfaction and commitment as mediating the effect of service quality on student loyalty as the user of Open University's Online Tutorial. Based on data analysis on student of Management program 229 as respondents with Structural Equation Modeling (SEM), this study found the relationship between: (1) positive influence of service quality to satisfaction and loyalty of students using tuton; (2) the positive effect of satisfaction on student loyalty using tuton; (3) satisfaction is a mediator between service quality and loyalty of students using tuton. Conversely, commitment has no positive effect on student loyalty as a tuton user. In addition, commitment does not mediates the effect of satisfaction on the loyalty of tuton users. Keywords: service quality, satisfaction, commitment, loyalty


2020 ◽  
Vol 48 (11) ◽  
pp. 1-7
Author(s):  
Guodong Yang

I proposed a model to explain how workplace fun is effective in facilitating employee creativity, with a focus on the mediating role of psychological safety in this relationship. Participants comprised 269 employees of hotels in China. Results show that workplace fun had a direct, significantly positive effect on employee creativity, as well as an indirect relationship through the mediator of psychological safety. These findings show that a fun work environment helps to enhance employee creativity. Thus, it is beneficial for managers of organizations to create a fun work environment, and they should also consider employees' sense of psychological safety when allowing employees to have fun at work.


2021 ◽  
Vol 75 (4) ◽  
Author(s):  
Hannah E. A. MacGregor ◽  
Aislinn Cottage ◽  
Christos C. Ioannou

Abstract Consistent inter-individual variation in behaviour within a population, widely referred to as personality variation, can be affected by environmental context. Feedbacks between an individual’s behaviour and state can strengthen (positive feedback) or weaken (negative feedback) individual differences when experiences such as predator encounters or winning contests are dependent on behavioural type. We examined the influence of foraging on individual-level consistency in refuge use (a measure of risk-taking, i.e. boldness) in three-spined sticklebacks, Gasterosteus aculeatus, and particularly whether changes in refuge use depended on boldness measured under control conditions. In the control treatment trials with no food, individuals were repeatable in refuge use across repeated trials, and this behavioural consistency did not differ between the start and end of these trials. In contrast, when food was available, individuals showed a higher degree of consistency in refuge use at the start of the trials versus controls but this consistency significantly reduced by the end of the trials. The effect of the opportunity to forage was dependent on behavioural type, with bolder fish varying more in their refuge use between the start and the end of the feeding trials than shyer fish, and boldness positively predicted the likelihood of feeding at the start but not at the end of the trials. This suggests a state-behaviour feedback, but there was no overall trend in how bolder individuals changed their behaviour. Our study shows that personality variation can be suppressed in foraging contexts and a potential but unpredictable role of feedbacks between state and behaviour. Significance statement In this experimental study, we examined how foraging influences consistency in risk-taking in individual three-spined sticklebacks. We show that bolder individuals become less consistent in their risk-taking behaviour than shyer individuals during foraging. Some bolder individuals reinforce their risk-taking behaviour, suggesting a positive feedback between state and behaviour, while others converge on the behaviour of shyer individuals, suggesting a negative feedback. In support of a role of satiation in driving negative feedback effects, we found that bolder individuals were more likely to feed at the start but not at the end of the trials. Overall, our findings suggest that foraging can influence personality variation in risk-taking behaviour; however, the role of feedbacks may be unpredictable.


Author(s):  
Danai Christopoulou ◽  
Nikolaos Papageorgiadis ◽  
Chengang Wang ◽  
Georgios Magkonis

AbstractWe study the role of the strength of Intellectual Property Rights (IPR) law protection and enforcement in influencing horizontal productivity spillovers from inward FDI to domestic firms in host countries. While most WTO countries adopted strong IPR legislation due to exogenous pressure resulting from the signing of the Trade-Related Aspects of IPR (TRIPS) agreement, public IPR enforcement strength continues to vary significantly between countries. We meta-analyse 49 studies and find that public IPR enforcement strength has a direct positive effect on horizontal productivity spillovers from inward FDI to domestic firms and a negative moderating effect on the relationship between IPR law protection strength and horizontal productivity spillovers from inward FDI to domestic firms.


2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Liangcong Fan ◽  
Zechun Ying ◽  
Yuemei Yuan ◽  
Xinchao Zhang ◽  
Bin Xu

Abstract Corrupt deals are commonly arranged by intermediaries. However, attempts to deter corruption pay little attention to the role of intermediaries in corrupt deals. This paper reports a laboratory bribery experiment on corruption designed to investigate how intermediaries with information about the lowest bribe that the official is willing to accept in a briber-initiated corrupt deal affect the effectiveness of the four-eyes-principle (FEP) on deterring corruption. We find that the introduction of the FEP significantly decreases the corruption level by increasing uncertainty. However, the presence of intermediaries with information completely offsets the positive effect of introducing the FEP on preventing corruption. Our findings suggest that further research on corruption should allow a more active role of intermediaries, and legislators should take the role of intermediaries into account when designing anti-corruption mechanisms.


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