scholarly journals Ciliary control of meiotic chromosomal pairing mechanics and germ cell morphogenesis

2021 ◽  
Author(s):  
Avishag Mytils ◽  
Vineet Kumar ◽  
Qiu Tao ◽  
Rachael Deis ◽  
Karine Levy ◽  
...  
Keyword(s):  
Germ Cell ◽  
Male Meiosis ◽  
The Novel ◽  
Cell Morphogenesis ◽  
Major Focus ◽  
Nuclear Dynamics ◽  
Chromosomal Pairing ◽  
Germline Cyst ◽  
Synaptonemal Complex Formation ◽  
Novel Concept

AbstractMeiosis is a cellular program essential for the production of haploid gametes. A hallmark of meiosis is chromosomal pairing via synaptonemal complexes, and a major focus traditionally has been to understand synaptonemal complex formation. However, chromosomal pairing also depends on cytoplasmic counterparts that tether and rotate telomeres on the nuclear envelope, shuffling chromosomes and mechanically driving their homology searches1–8. Rotating telomeres slide on perinuclear microtubules and are ultimately pulled towards the centrosome7,9,10, forming the “zygotene chromosomal bouquet configuration”11. The bouquet is universally conserved and is essential for pairing and fertility1–8,12. However, despite its discovery in 190011, how the cytoplasmic counterparts of bouquet formation are mechanically regulated has remained enigmatic. Here, by studying zebrafish oogenesis, we report and comprehensively characterize the “zygotene cilium” - a previously unrecognized cilium in oocytes. We show that the zygotene cilium specifically connects to the bouquet centrosome and constitutes a cable system of the cytoplasmic bouquet machinery. Farther, zygotene cilia extend throughout the germline cyst, a conserved cellular organization of germ cells. By analyzing multiple ciliary mutants, we demonstrate that the zygotene cilium is essential for chromosomal pairing, germ cell morphogenesis, ovarian development and fertility. We further show that the zygotene cilium is conserved in both male meiosis in zebrafish, as well as in mammalian oogenesis. Our work uncovers the novel concept of a cilium as a critical player in meiosis and sheds new light on reproduction phenotypes in ciliopathies. Furthermore, most cells in metazoans are ciliated and exhibit specific nuclear dynamics. We propose a cellular paradigm that cilia can control chromosomal dynamics.

scholarly journals Analysis of STAG3 variants in Chinese non-obstructive azoospermia patients with germ cell maturation arrest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wen Liu ◽  
Xuan Gao ◽  
Haobo Zhang ◽  
Ran Liu ◽  
Yongzhi Cao ◽  
...  
Keyword(s):  
Germ Cell ◽  
Male Meiosis ◽  
Cell Maturation ◽  
Control Group ◽  
Obstructive Azoospermia ◽  
The Novel ◽  
Nucleotide Polymorphisms ◽  
Maturation Arrest ◽  
Ethnic Populations ◽  
Genotype Frequencies

AbstractSTAG3 is essential for male meiosis and testis of male Stag3−/− mice shows the histopathological type of germ cell maturation arrest (MA). Whether variants of the STAG3 gene exist in Chinese idiopathic non-obstructive azoospermia (NOA) patients needs to be determined. We recruited 58 Chinese NOA men with MA who underwent testis biopsy and 192 fertile men as the control group. The 34 exons of the STAG3 gene were amplified using polymerase chain reaction (PCR) and sequenced. We identified eight novel single nucleotide polymorphisms (SNPs), including two missense SNPs (c.433T > C in exon2 and c.553A > G in exon3), three synonymous SNPs (c.539G > A, c.569C > T in exon3, and c.1176C > G in exon8), and three SNPs in introns. The allele and genotype frequencies of the novel and other SNPs have no significant differences between two groups. Our results indicated that variants in the coding sequence of the STAG3 gene were uncommon in NOA patients with MA in Chinese population. Future studies in large cohorts of different ethnic populations will be needed to determine the association between the STAG3 gene and NOA.

scholarly journals Analysis of STAG3 Mutations in Chinese Non-Obstructive Azoospermia Patients with Germ Cell Maturation Arrest

2020 ◽  
Author(s):  
Wen Liu ◽  
Xuan Gao ◽  
Haobo Zhang ◽  
Ran Liu ◽  
Yongzhi Cao ◽  
...  
Keyword(s):  
Germ Cell ◽  
Male Meiosis ◽  
Cell Maturation ◽  
Control Group ◽  
Obstructive Azoospermia ◽  
The Novel ◽  
Nucleotide Polymorphisms ◽  
Maturation Arrest ◽  
Ethnic Populations ◽  
Genotype Frequencies

Abstract Background STAG3 is essential for male meiosis and testis of male Stag3-/- mice shows the histopathological type of germ cell maturation arrest (MA). Whether mutations of the STAG3 gene exist in Chinese idiopathic non-obstructive azoospermia (NOA) patients needs to be determined. Methods We recruited 58 Chinese NOA men with MA who underwent testis biopsy and 192 fertile men as the control group. The 34 exons of the STAG3 gene were amplified using polymerase chain reaction (PCR) and sequenced. Results We identified eight novel single nucleotide polymorphisms (SNPs), including two missense SNPs (c.433T>C in exon2 and c.553A>G in exon3), three synonymous SNPs (c.539G>A, c.569C>T in exon3, and c.1176C>G in exon8), and three SNPs in introns. The allele and genotype frequencies of the novel and other SNPs have no significant differences between two groups. Conclusions Our results indicated that mutations in the coding sequence of the STAG3 gene were uncommon in NOA patients with MA in Chinese population. Future studies in large cohorts of different ethnic populations will be needed to determine the association between the STAG3 gene and NOA.

scholarly journals Hormad1 Is a Germ Cell-Specific HORMA Containing Protein Required for Synaptonemal Complex Formation in Male Meiosis.

2009 ◽  
Vol 81 (Suppl_1) ◽  
pp. 172-172
Author(s):  
Yonghyun Shin ◽  
Malgorzata Kloc ◽  
Youngsok Choi ◽  
Marvin L. Meistrich ◽  
Aleksandar Rajkovic
Keyword(s):  
Complex Formation ◽  
Germ Cell ◽  
Synaptonemal Complex ◽  
Male Meiosis ◽  
Synaptonemal Complex Formation

scholarly journals Racism and Antiracism in the Liberal International Order

2020 ◽  
pp. 1-24
Author(s):  
Zoltán I. Búzás
Keyword(s):  
International Relations ◽  
Racial Inequality ◽  
Racial Diversity ◽  
International Order ◽  
Interdisciplinary Studies ◽  
Racial Equality ◽  
The Novel ◽  
Current Regime ◽  
Novel Concept ◽  
Comprehensive Framework

Abstract Formal racial equality is a key aspect of the current Liberal International Order (LIO). It is subject to two main challenges: resurgent racial nationalism and substantive racial inequality. Combining work in International Relations with interdisciplinary studies on race, I submit that these challenges are the latest iteration of struggles between two transnational coalitions over the LIO's central racial provisions, which I call racial diversity regimes (RDRs). The traditional coalition has historically favored RDRs based on racial inequality and racial nationalism. The transformative coalition has favored RDRs based on racial equality and nonracial nationalism. I illustrate the argument by tracing the development of the liberal order's RDR as a function of intercoalitional struggles from one based on racial nationalism and inequality in 1919 to the current regime based on nonracial nationalism and limited equality. Today, racial nationalists belong to the traditional coalition and critics of racial inequality are part of the transformative coalition. The stakes of their struggles are high because they will determine whether we will live in a more racist or a more antiracist world. This article articulates a comprehensive framework that places race at the heart of the liberal order, offers the novel concept of “embedded racism” to capture how sovereignty shields domestic racism from foreign interference, and proposes an agenda for mainstream International Relations that takes race seriously.

scholarly journals Using green infrastructure to stimulate discourse with and for planning practice: experiences with fuzzy concepts from a pan-European, a national and a local perspective

2021 ◽  
Author(s):  
Rieke Hansen ◽  
Martina van Lierop ◽  
Werner Rolf ◽  
Damjana Gantar ◽  
Ina Šuklje Erjavec ◽  
...  
Keyword(s):  
Green Infrastructure ◽  
Regional Cooperation ◽  
Knowledge Exchange ◽  
Stakeholder Involvement ◽  
The Novel ◽  
Planning Practice ◽  
Regional Project ◽  
Development Processes ◽  
Guidance Documents ◽  
Novel Concept

AbstractConcepts such as green infrastructure, nature-based solutions, and ecosystem services gained popularity in recent discourses on urban planning. Despite their recognition as innovative concepts, all of them share a degree of ambiguity. Fuzziness can be a weakness but also an opportunity to shape novel concepts together with the stakeholders that are supposed to implement them in the planning practice. The paper traces concept development processes of green infrastructure through transdisciplinary knowledge exchange in three different projects, a European and a national research project and a local city-regional project as part of an EU regional cooperation project. In all projects, the green infrastructure concept evolved in different stages. Stakeholder involvement during these stages span from consultation to co-creation. The cases reveal two different approaches: concepts that are developed “for planning practice” might be based on a plethora of insight via consultation, while those “with planning practice” foster co-creation and might result in high acceptance among the involved stakeholders. Depending on the purpose of the novel concept, each approach can be beneficial and result in practice-related and operational products, such as guidance documents or planning strategies. However, the cases also show that in any new context an exchange about fuzzy concepts is not only needed but also a chance to stimulate cooperation and joint understanding about urban challenges and how to address them.

scholarly journals CD5 costimulation induces stable Th17 development by promoting IL-23R expression and sustained STAT3 activation

Blood ◽  
2011 ◽  
Vol 118 (23) ◽  
pp. 6107-6114 ◽  
Author(s):  
Jelle de Wit ◽  
Yuri Souwer ◽  
Astrid J. van Beelen ◽  
Rosa de Groot ◽  
Femke J. M. Muller ◽  
...  
Keyword(s):  
Th17 Cells ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Orphan Receptor ◽  
The Novel ◽  
Cd28 Costimulation ◽  
Th17 Differentiation ◽  
Novel Concept ◽  
Transcription 3 ◽  
Lymphocyte Receptors

Abstract IL-17–producing CD4+ T helper (Th17) cells are important for immunity against extracellular pathogens and in autoimmune diseases. The factors that drive Th17 development in human remain a matter of debate. Here we show that, compared with classic CD28 costimulation, alternative costimulation via the CD5 or CD6 lymphocyte receptors forms a superior pathway for human Th17-priming. In the presence of the Th17-promoting cytokines IL-1β, IL-6, IL-23, and transforming growth factor-β (TGF-β), CD5 costimulation induces more Th17 cells that produce higher amounts of IL-17, which is preceded by prolonged activation of signal transducer and activator of transcription 3 (STAT3), a key regulator in Th17 differentiation, and enhanced levels of the IL-17–associated transcription factor retinoid-related orphan receptor-γt (ROR-γt). Strikingly, these Th17-promoting signals critically depend on CD5-induced elevation of IL-23 receptor (IL-23R) expression. The present data favor the novel concept that alternative costimulation via CD5, rather than classic costimulation via CD28, primes naive T cells for stable Th17 development through promoting the expression of IL-23R.

scholarly journals Phylogenetic Core Groups: a promising concept in search of a consistent methodological framework

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Alberto Pascual-García
Keyword(s):  
Microbial Communities ◽  
Microbial Ecology ◽  
Environmental Conditions ◽  
The Novel ◽  
Methodological Framework ◽  
Operational Taxonomic Units ◽  
Traditional Classification ◽  
Taxonomical Classification ◽  
Novel Concept

AbstractIn this comment, we analyse the conceptual framework proposed by Aguirre de Cárcer (Microbiome 7:142, 2019), introducing the novel concept of Phylogenetic Core Groups (PCGs). This notion aims to complement the traditional classification in operational taxonomic units (OTUs), widely used in microbial ecology, to provide a more intrinsic taxonomical classification which avoids the use of pre-determined thresholds. However, to introduce this concept, the author frames his proposal in a wider theoretical framework based on a conceptualization of selection that we argue is a tautology. This blurs the subsequent formulation of an assembly principle for microbial communities, favouring that some contradictory examples introduced to support the framework appear aligned in their conclusions. And more importantly, under this framework and its derived methodology, it is not possible to infer PCGs from data in a consistent way. We reanalyse the proposal to identify its logical and methodological flaws and, through the analysis of synthetic scenarios, we propose a number of methodological refinements to contribute towards the determination of PCGs in a consistent way. We hope our analysis will promote the exploration of PCGs as a potentially valuable tool, helping to bridge the gap between environmental conditions and community composition in microbial ecology.

Performance Benefits of R718 Turbo-Compression Cycle Using 3-Port Condensing Wave Rotors

2004 ◽  
Author(s):  
Amir A. Kharazi ◽  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Performance Enhancement ◽  
The Novel ◽  
Wave Rotor ◽  
Flash Evaporation ◽  
Pressurized Water ◽  
Wave Rotors ◽  
Compression Cycle ◽  
Performance Map ◽  
Wave Compression ◽  
Novel Concept

A number of technical challenges have often hindered the economical application of refrigeration cycles using water (R718) as refrigerant. The novel concept of condensing wave rotor provides a solution for performance improvement of R718 refrigeration cycles. The wave rotor implementation can increase efficiency and reduce the size and cost of R718 units. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor — all in one dynamic process. In this study, the underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. A computer program based on a thermodynamic model is generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The detailed thermodynamic approach for the baseline and the modified cycles is described. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A generated performance map summarizes the findings.

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