scholarly journals A model for estimating traction force magnitude reveals differential regulation of actomyosin activity and matrix adhesion number in response to smooth muscle cell spreading

2019 ◽  
Author(s):  
Sultan Ahmed ◽  
Panashe Mabeza ◽  
Derek T Warren
Keyword(s):  
Smooth Muscle ◽  
Linear Regression Analysis ◽  
Traction Force ◽  
Strongly Correlated ◽  
Matrix Rigidity ◽  
Aortic Compliance ◽  
Force Microscopy ◽  
Force Magnitude ◽  
The Relationship ◽  
Novel Model

AbstractDecreased aortic compliance is associated with ageing and vascular disease, including atherosclerosis and hypertension. Ultimately, changes in aortic compliance are driven by altered ECM composition however, recent findings have identified a cellular component to decreased aortic compliance observed in ageing and hypertension. Vascular smooth muscle cells (VSMCs) line the blood vessel wall and VSMC contraction regulates vascular tone and contributes to aortic compliance. Mechanical cues derived from the ECM influence VSMC function, yet whether ECM rigidity influences VSMC force generation remains unclear. In this study, we describe the relationship between VSMC spreading, traction force magnitude and matrix rigidity. Importantly, we show that spreading predicts integrated traction force (integrated-TF) magnitude independently of matrix rigidity. Using linear regression analysis, we have generated a model for calculating integrated-TF from VSMC area. This model closely predicts the integrated traction force measured by live VSMC traction force microscopy. Vinculin staining analysis revealed that spreading strongly correlated with adhesion number per VSMC, suggesting that increased VSMC integrated-TF was due to enhanced matrix anchor points. Further analysis revealed that calculated integrated-TF per adhesion was reduced by matrix rigidity, however, adhesion number/μm2increased, resulting in the average integrated-TF/μm2remaining unaltered. As a result, the integrated-TF/VSMC spreading relationship is independent of matrix rigidity. Therefore, our study has identified and validated a novel model to predict and understand the mechanisms influencing VSMC traction force magnitude.

scholarly journals Discussion of “Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion” (Álvarez-González, B., Bastounis, E., Meili, R., del Alamo, J. C., Firtel, R. A., and Lasheras, J. C., 2014, ASME Appl. Mech. Rev., 66(5), p. 050804)

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
Xavier Trepat
Keyword(s):  
Cell Motility ◽  
Traction Force ◽  
Traction Forces ◽  
Force Microscopy ◽  
Amoeboid Cell ◽  
Cell Locomotion ◽  
Cell Cycle Synchronization ◽  
Open Questions ◽  
Universal Feature ◽  
The Relationship

A virtually universal feature of adherent cells is their ability to exert traction forces. To measure these forces, several methods have been developed over the past 15 years. In this issue of Applied Mechanics Reviews, Álvarez-González and co-workers review their own traction force microscopy approach and its application to the study of amoeboid cell locomotion. They show that the cycle of cell motility is exquisitely synchronized by a cycle of traction forces. In addition, they show how traction forces and cell cycle synchronization are affected by myosin and SCAR/WAVE mutants. Here, I discuss some open questions that derive from the work of the authors and other laboratories as regards the relationship between cell motility and traction forces.

scholarly journals Crosstalk between myosin II and formin functions in the regulation of force generation and actomyosin dynamics in stress fibers

2021 ◽  
Author(s):  
Yukako Nishimura ◽  
Shidong Shi ◽  
Qingsen Li ◽  
Alexander D. Bershadsky ◽  
Virgile Viasnoff
Keyword(s):  
Contractile Activity ◽  
Myosin Ii ◽  
Focal Adhesions ◽  
Traction Force ◽  
Stress Fiber ◽  
Force Generation ◽  
Stress Fibers ◽  
Force Microscopy ◽  
Fiber Dynamics ◽  
The Relationship

REF52 fibroblasts have a well-developed contractile machinery, the most prominent elements of which are actomyosin stress fibers with highly ordered organization of actin and myosin IIA filaments. The relationship between contractile activity and turnover dynamics of stress fibers is not sufficiently understood. Here, we simultaneously measured the forces exerted by stress fibers (using traction force microscopy or micropillar array sensors) and the dynamics of actin and myosin (using photoconversion-based monitoring of actin incorporation and high-resolution fluorescence microscopy of myosin II light chain). Our data revealed new features of the crosstalk between myosin II-driven contractility and stress fiber dynamics. During normal stress fiber turnover, actin incorporated all along the stress fibers and not only at focal adhesions. Incorporation of actin into stress fibers/focal adhesions, as well as actin and myosin II filaments flow along stress fibers, strongly depends on myosin II activity. Myosin II-dependent generation of traction forces does not depend on incorporation of actin into stress fibers per se, but still requires formin activity. This previously overlooked function of formins in maintenance of the actin cytoskeleton connectivity could be the main mechanism of formin involvement in traction force generation.

The Influences of Palindromes in mRNA on Protein Folding Rates

2020 ◽  
Vol 27 (4) ◽  
pp. 303-312 ◽  
Author(s):  
Ruifang Li ◽  
Hong Li ◽  
Sarula Yang ◽  
Xue Feng
Keyword(s):  
Protein Folding ◽  
Regression Analysis ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Folding Rate ◽  
Folding Rates ◽  
Negative Linear Correlation ◽  
Protein Folding Rate ◽  
The Relationship ◽  
Structure Environment

Background: It is currently believed that protein folding rates are influenced by protein structure, environment and temperature, amino acid sequence and so on. We have been working for long to determine whether and in what ways mRNA affects the protein folding rate. A large number of palindromes aroused our attention in our previous research. Whether these palindromes do have important influences on protein folding rates and what’s the mechanism? Very few related studies are focused on these problems. Objective: In this article, our motivation is to find out if palindromes have important influences on protein folding rates and what’s the mechanism. Method: In this article, the parameters of the palindromes were defined and calculated, the linear regression analysis between the values of each parameter and the experimental protein folding rates were done. Furthermore, to compare the results of different kinds of proteins, proteins were classified into the two-state proteins and the multi-state proteins. For the two kinds of proteins, the above linear regression analysis were performed respectively. Results : Protein folding rates were negatively correlated to the palindrome frequencies for all proteins. An extremely significant negative linear correlation appeared in the relationship between palindrome densities and protein folding rates. And the repeatedly used bases by different palindromes simultaneously have an important effect on the relationship between palindrome density and protein folding rate. Conclusion: The palindromes have important influences on protein folding rates, and the repeatedly used bases in different palindromes simultaneously play a key role in influencing the protein folding rates.

scholarly journals Investigating the Relationship between Public Satisfaction and Public Environmental Participation during Government Treatment of Urban Malodorous Black River in China

2021 ◽  
Vol 13 (6) ◽  
pp. 3584
Author(s):  
Shiwang Yu ◽  
Jianxia Bao ◽  
Wen Ding ◽  
Xue Chen ◽  
Xiaonan Tang ◽  
...  
Keyword(s):  
Public Participation ◽  
Public Perception ◽  
Action Plan ◽  
Linear Regression Analysis ◽  
Chinese Government ◽  
Whole Process ◽  
Residential Communities ◽  
Behavior Health ◽  
The Relationship ◽  
Environmental Participation

During China’s rapid economic development and urbanization, numerous cases of urban malodorous black river (MBR) have occurred. MBR refers to a polluted urban river that smells bad, is almost black in color, has no aquatic plants or animals, and that consequently causes many social and environmental problems. The Chinese government has sought public participation during the whole process of MBR treatment as part of a comprehensive action plan to improve residents’ satisfaction with their environment. To investigate the influencing factors of public participation and satisfaction, a questionnaire survey was conducted among residential communities close to an MBR. SPSS 22.0 was employed to conduct an analysis of the collected data, using factor analysis, correlation analysis, and linear regression analysis. The results indicate that there is a direct relationship between public satisfaction and the factors of government treatment, public perception and public participation behaviors, such as engagement behavior, supervision behavior, health influence, and compensation measures.

The Personal Sociability and Connections Scale (PeSCS): Development and initial assessment at a primary care facility

2021 ◽  
pp. 002076402199351
Author(s):  
Emmanouil K Symvoulakis ◽  
Manolis Linardakis ◽  
Apostolos Kamekis ◽  
Myfanwy Morgan ◽  
Spyridon Klinis
Keyword(s):  
Primary Care ◽  
Social Isolation ◽  
Convergent Validity ◽  
Interpersonal Relations ◽  
Linear Regression Analysis ◽  
Care Facility ◽  
Initial Assessment ◽  
Multivariate Linear Regression Analysis ◽  
Northern Greece ◽  
The Relationship

Purpose: An individual’s lack of social connections and social isolation is often associated with feelings of loneliness which is regarded as having a negative effect on health. This paper describes the development and assessment of a 10 item ‘Personal Sociability and Connections Scale’ (PeSCS) to measure individual’s disposition and accompanying skills to seek out companionship and engage in interpersonal relations. Methods: The study was conducted at a rural primary care unit in Northern Greece. A total of 199 attenders were recruited over a 6-week period in 2020 and questionnaires completed. This informed the 10-items PeSCS that comprises Social, Behavioral, and Emotional components focusing on the expression of social comfort, willingness to share experiences, stories and concepts, and feelings of similarity at first contact. Reliability of the PeSC scale was assessed and the relationship with scale scores examined as an indicator of convergent validity. A multivariate linear regression analysis was performed to examine the relationship of PeSC scale score with the characteristics of participants. Results: Assessment of reliability of PeSC scale produced a Cronbach’s alpha of 0.809. The relationship between components and the total PeSCS scores identified significant correlations ( p < .001). At a multivariate level, male gender was the sample characteristic with a significant association with scale levels ( p < .05) and higher annual income with Social component ( p < .05). Otherwise the distribution of sociability dispositions was similar across population groups. Conclusion: The 10-item PeSC scale forms a simple and quick to complete measure whose overall reliability was rated as ‘meritorious’. The PeSC instrument may be a useful tool for assessing the causes and appropriate responses to the negative health effects of loneliness and social isolation.

Male Sterility and Meiotic Drive Associated With Sex Chromosome Rearrangements in Drosophila: Role of X-Y Pairing

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 143-155 ◽  
Author(s):  
Bruce D McKee ◽  
Kathy Wilhelm ◽  
Cynthia Merrill ◽  
Xiao-jia Ren
Keyword(s):  
Male Sterility ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
Repeated Sequence ◽  
Meiotic Pairing ◽  
Intergenic Spacers ◽  
Male Specific ◽  
The Relationship ◽  
Novel Model

Abstract In Drosophila melanogaster, deletions of the pericentromeric X heterochromatin cause X-Y nondisjunction, reduced male fertility and distorted sperm recovery ratios (meiotic drive) in combination with a normal Y chromosome and interact with Y-autosome translocations (T(Y;A)) to cause complete male sterility. The pericentromeric heterochromatin has been shown to contain the male-specific X-Y meiotic pairing sites, which consist mostly of a 240-bp repeated sequence in the intergenic spacers (IGS) of the rDNA repeats. The experiments in this paper address the relationship between X-Y pairing failure and the meiotic drive and sterility effects of Xh deletions. X-linked insertions either of complete rDNA repeats or of rDNA fragments that contain the IGS were found to suppress X-Y nondisjunction and meiotic drive in Xh−/Y males, and to restore fertility to Xh−/T(Y;A) males for eight of nine tested Y-autosome translocations. rDNA fragments devoid of IGS repeats proved incapable of suppressing either meiotic drive or chromosomal sterility. These results indicate that the various spermatogenic disruptions associated with X heterochromatic deletions are all consequences of X-Y pairing failure. We interpret these findings in terms of a novel model in which misalignment of chromosomes triggers a checkpoint that acts by disabling the spermatids that derive from affected spermatocytes.

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