scholarly journals Septins and a formin have distinct functions in anaphase chiral cortical rotation in the C. elegans zygote

2021 ◽  
pp. mbc.E20-09-0576
Author(s):  
Adhham Zaatri ◽  
Jenna A. Perry ◽  
Amy Shaub Maddox
Keyword(s):  
Network Connectivity ◽  
Division Plane ◽  
C Elegans ◽  
Early Anaphase ◽  
Simultaneous Loss ◽  
Actomyosin Cytoskeleton ◽  
Future Work ◽  
The Relationship ◽  
Shed Light ◽  
Anterior Posterior

Many cells and tissues exhibit chirality that stems from the chirality of proteins and polymers. In the C. elegans zygote actomyosin contractility drives chiral rotation of the entire cortex circumferentially around the division plane during anaphase. How contractility is translated to cell-scale chirality, and what dictates handedness, are unknown. Septins are candidate contributors to cell-scale chirality because they anchor and crosslink the actomyosin cytoskeleton. We report that septins are required for anaphase cortical rotation. In contrast, the formin CYK-1, which we found to be enriched in the posterior in early anaphase, is not required for cortical rotation, but contributes to its chirality. Simultaneous loss of septin and CYK-1 function led to abnormal and often reversed cortical rotation. Our results suggest that anaphase contractility leads to chiral rotation by releasing torsional stress generated during formin-based polymerization, which is polarized along the cell anterior-posterior axis, and which accumulates due to actomyosin network connectivity. Our findings shed light on the molecular and physical bases for cellular chirality in the C. elegans zygote. We also identify conditions in which chiral rotation fails but animals are developmentally viable, opening avenues for future work on the relationship between early embryonic cellular chirality and animal body plan. [Media: see text] [Media: see text]

scholarly journals Septins and a formin have distinct functions in anaphase chiral cortical rotation in the C. elegans zygote

2020 ◽  
Author(s):  
Adhham Zaatri ◽  
Jenna A. Perry ◽  
Amy Shaub Maddox
Keyword(s):  
Molecular Mechanisms ◽  
Division Plane ◽  
C Elegans ◽  
Early Anaphase ◽  
Simultaneous Loss ◽  
Cortical Contractility ◽  
Actomyosin Cytoskeleton ◽  
Future Work ◽  
The Relationship ◽  
Shed Light

AbstractMany cells and tissues exhibit chirality that stems from the chirality of constituent proteins and polymers. For example, the C. elegans zygote undergoes an actomyosin-driven chiral rotation in which the entire cortex is displaced circumferentially around the division plane during anaphase. This phenomenon thus relates to how force and chirality are translated across scales. Although it is known that actomyosin contractility drives this rotation, the molecular mechanisms transmitting contractility to chiral movement, and dictating handedness, are not understood. Septins are candidates for contributing to cell-scale chirality due to their ability to anchor and organize the actomyosin cytoskeleton. Here, we report that septins are required for anaphase cortical rotation. In contrast, the formin CYK-1, which we found to be enriched in the posterior in early anaphase, is not required for cortical rotation, but contributes to its chirality. Simultaneous loss of septin and CYK-1 function led to highly abnormal and often reversed cortical rotation. We propose a model by which anaphase cortical contractility is biased in a chiral fashion via interaction between the circumferential cytokinetic ring and perpendicular, longitudinal formin-based actin bundles that have accumulated torsional stress during formin-based polymerization. Our findings thus shed light on the molecular and physical bases for cellular chirality in the C. elegans zygote. We also identify conditions in which chiral rotation fails but animals are developmentally viable, opening avenues for future work on the relationship between early embryonic cellular chirality and animal body plan.

scholarly journals Interactions between the WEE-1.3 kinase and the PAM-1 aminopeptidase in oocyte maturation and the early C. elegans embryo

2021 ◽  
Author(s):  
Dorothy Benton ◽  
Eva C Jaeger ◽  
Arielle Kilner ◽  
Ashley Kimble ◽  
Josh Lowry ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Oocyte Maturation ◽  
Protective Role ◽  
C Elegans ◽  
Direct Target ◽  
The One ◽  
Actomyosin Cytoskeleton ◽  
Embryonic Viability ◽  
Anterior Posterior

Abstract Puromycin-sensitive aminopeptidases are found across phyla and are known to regulate the cell-cycle and play a protective role in neurodegenerative disease. PAM-1 is a puromycin-sensitive aminopeptidase important for meiotic exit and polarity establishment in the one-cell Caenorhabditis elegans embryo. Despite conservation of this aminopeptidase, little is known about its targets during development. In order to identify novel interactors, we conducted a suppressor screen and isolated four suppressing mutations in three genes that partially rescued the maternal-effect lethality of pam-1 mutants. Suppressed strains show improved embryonic viability and polarization of the anterior-posterior axis. We identified a missense mutation in wee-1.3 in one of these suppressed strains. WEE-1.3 is an inhibitory kinase that regulates maturation promoting factor. While the missense mutation suppressed polarity phenotypes in pam-1, it does so without restoring centrosome-cortical contact or altering the cortical actomyosin cytoskeleton. To see if PAM-1 and WEE-1.3 interact in other processes, we examined oocyte maturation. While depletion of wee-1.3 causes sterility due to precocious oocyte maturation, this effect was lessened in pam-1 worms, suggesting that PAM-1 and WEE-1.3 interact in this process. Levels of WEE-1.3 were comparable between wild-type and pam-1 strains, suggesting that WEE-1.3 is not a direct target of the aminopeptidase. Thus, we have established an interaction between PAM-1 and WEE-1.3 in multiple developmental processes and have identified suppressors that are likely to further our understanding of the role of puromycin-sensitive aminopeptidases during development.

Language, Politics and Society in the Middle East

2018 ◽  
Author(s):  
Abeer AlNajjar
Keyword(s):  
Middle East ◽  
Linguistic Landscape ◽  
Language Politics ◽  
Road Signs ◽  
Grassroots Initiatives ◽  
Language And Politics ◽  
Development Of Language ◽  
Core Questions ◽  
The Relationship ◽  
Shed Light

This book aims to shed light on core questions relating to language and society, language and conflict, and language and politics, in relation to a changing Middle East. While the book focuses on Arabic, it goes way beyond a purely linguistic analysis by bringing to the fore a set of pressing questions about the relationship between Arabic and society. For example, it touches on the development of language policy via an examination of administrative mandates (top-down) in contrast to grassroots initiatives (bottom-up); the deeper layers of the linguistic landscape that highlight the connection between politics, conflict, identity, road signs and street names; Arabic studies and Arabic identity and the myriad ways countries deal simultaneously with globalisation while also seeking to strengthen local and national identity, and more.

Identifying Physico-Chemical Laws from the Robotically Collected Data

2019 ◽  
Author(s):  
Liwei Cao ◽  
Danilo Russo ◽  
Vassilios S. Vassiliadis ◽  
Alexei Lapkin
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Predictor Variable ◽  
Physical Models ◽  
Training Data ◽  
Mixed Integer ◽  
Physico Chemical ◽  
Data Points ◽  
Future Work ◽  
The Relationship

<p>A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.</p><p><br></p>

Considering Others’ Mental States Causally Increases Feelings of Social Bonding and Information Sharing

2019 ◽  
Author(s):  
Elisa Baek ◽  
Diana Tamir ◽  
Emily B. Falk
Keyword(s):  
Social Behavior ◽  
Information Sharing ◽  
Mental States ◽  
Social Bonding ◽  
Health News ◽  
Brain Behavior ◽  
The Relationship ◽  
Share Information ◽  
Shed Light ◽  
Mentalizing System

Information sharing is a ubiquitous social behavior. What causes people to share? Mentalizing, or considering the mental states of other people, has been theorized to play a central role in information sharing, with higher activity in the brain’s mentalizing system associated with increased likelihood to share information. In line with this theory, we present novel evidence that mentalizing causally increases information sharing. In three pre-registered studies (n = 400, 840, and 3500 participants), participants who were instructed to consider the mental states of potential information receivers indicated higher likelihood to share health news compared to a control condition where they were asked to reflect on the content of the article. Certain kinds of mentalizing were particularly effective; in particular, considering receivers’ emotional and positive mental states, led to the greatest increase in likelihood to share. The relationship between mentalizing and sharing was mediated by feelings of closeness with potential receivers. Mentalizing increased feelings of connectedness to potential receivers, and in turn, increased likelihood of information sharing. Considering receivers’ emotional, positive, and inward-focused mental states was most effective at driving participants to feel closer with potential receivers and increase sharing. Data provide evidence for a causal relationship between mentalizing and information sharing and provide insight about the mechanism linking mentalizing and sharing. Taken together, these results advance theories of information sharing and shed light on previously observed brain-behavior relationships.

سؤال العلاقة بين الفطرة والشريعة: قراءة معرفية (The Question of the Relationship between Shariah and Human Nature/fitrah: An Epistemological Review)

2018 ◽  
Vol 15 (1) ◽  
pp. 1-42
Author(s):  
المختار الأحمر
Keyword(s):  
Human Nature ◽  
Islamic Law ◽  
Interconnected Systems ◽  
Evolutionary Aspect ◽  
Islamic Thought ◽  
The Creation ◽  
The Relationship ◽  
Evolutionary Aspects ◽  
Shed Light

الملخّص يتناول البحث علاقة الفطرة بالشريعة في التفكير الإسلامي، وما تطرحه هذه العلاقة سواء على مستوى بيان الجوانب المتعلقة بخَلْق الإنسان وما فُطِر عليه ابتداء، وهذا البعد يمثّل الجانب التكوني في مفهوم الفطرة، أو على المستوى المتعلق بالشريعة وفطريتها، أي أنها جارية وفق ما يدركه العقل وتشهد به الفطرة، وهذا البعد يمثّل الجانب التشريعي الذي يطرحه مفهوم الفطرة. لقد زخرت أغلب الكتابات بتناول جانبا واحدا مما يتيحه أو يعكسه مفهوم الفطرة، لكن البحث في العلاقة التناسبية بين الفطرة والشريعة، وما يتيحه هذا النظر المتلازم بين المفهومين على مستوى الإمكانات المتعلقة بقدرات الإنسان الفطرية في فهم وتعقّل الخطاب الشرعي والأحكام التكليفية، والوقوف على غاياته ومقاصده، يبقى في حاجة إلى البحث والاستقصاء. ولذلك تأتي هذه الدراسة لتسليط الضوء على الجانب التشريعي والتكويني في علاقة الشريعة بالفطرة، باعتبارهما نظامين متلازمين يتيحان فهم طبيعة الشريعة وأحكامها ومقاصدها من جهة، وتحديد جوهر وماهية الإنسان الفطرية وإمكاناته في تعقّل هذه الشريعة من جهة ثانية.                  الكلمات المفتاحية: الفطرة، الشريعة، الدين، التكاليف، العقل. Abstract This research addresses the relationship between premordial human nature (fitrah) and Islamic law (SharÊÑah) within the frame of Islamic thought, while exploring the questions it raises at two levels. The first level explains the aspects related to the creation of man and what has initially been bestowed upon him, which represents the evolutionary aspect of the concept of fiÏrah. The second level is related to SharÊÑah and its nature, which evolves according to what is percieved by reason and witnessed by fiÏrah; this represents the legislative aspect presented by the concept of fiÏrah. The majority of studies to date address a single aspect of the illustrations of the concept of fiÏrah. However, research on the dialectic relationship between fiÏrah and SharÊÑah and what its relevant concurrent view provides at the level of potentials related to human innate capacities in understanding and realizing SharÊÑah discourse and mandatory provisions as well as understanding its objectives  remains scarce and requires further research and investigation. Therefore, this study intends to shed light on the legislative and evolutionary aspects of the relationship between SharÊÑah and fiÏrah as two interconnected systems that allow for the understanding of the nature of SharÊÑah, its provisions and purposes, as well as identifying the essence of human innate nature and its potential in perceiving SharÊÑah. Keywords: human nature (fiÏrah), Islamic law (SharÊÑah), religious mandates (TakÉlif), religion, intellect (ÑAqal).

Adolescent Language: Models, Assessment, and Links to Reading

2019 ◽  
Author(s):  
Amanda Goodwin ◽  
Yaacov Petscher ◽  
Jamie Tock
Keyword(s):  
Reading Comprehension ◽  
Bifactor Model ◽  
Language Models ◽  
Multiple Group ◽  
Global Factor ◽  
Eighth Grade Students ◽  
Key Aspects ◽  
Future Work ◽  
The Relationship ◽  
Best Fit

Various models have highlighted the complexity of language. Building on foundational ideas regarding three key aspects of language, our study contributes to the literature by 1) exploring broader conceptions of morphology, vocabulary, and syntax, 2) operationalizing this theoretical model into a gamified, standardized, computer-adaptive assessment of language for fifth to eighth grade students entitled Monster, PI, and 3) uncovering further evidence regarding the relationship between language and standardized reading comprehension via this assessment. Multiple-group item response theory (IRT) across grades show that morphology was best fit by a bifactor model of task specific factors along with a global factor related to each skill. Vocabulary was best fit by a bifactor model that identifies performance overall and on specific words. Syntax, though, was best fit by a unidimensional model. Next, Monster, PI produced reliable scores suggesting language can be assessed efficiently and precisely for students via this model. Lastly, performance on Monster, PI explained more than 50% of variance in standardized reading, suggesting operationalizing language via Monster, PI can provide meaningful understandings of the relationship between language and reading comprehension. Specifically, considering just a subset of a construct, like identification of units of meaning, explained significantly less variance in reading comprehension. This highlights the importance of considering these broader constructs. Implications indicate that future work should consider a model of language where component areas are considered broadly and contributions to reading comprehension are explored via general performance on components as well as skill level performance.

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