scholarly journals The Laminopathies and the Insights They Provide into the Structural and Functional Organization of the Nucleus

2020 ◽  
Vol 21 (1) ◽  
pp. 263-288 ◽  
Author(s):  
Xianrong Wong ◽  
Colin L. Stewart
Keyword(s):  
Health Care ◽  
Nuclear Envelope ◽  
Functional Organization ◽  
Nuclear Periphery ◽  
Genetic Material ◽  
Cytoskeletal Organization ◽  
Functional Roles ◽  
Storage Organelle ◽  
Transcriptional Output ◽  
Contemporary Health Care

In recent years, our perspective on the cell nucleus has evolved from the view that it is a passive but permeable storage organelle housing the cell's genetic material to an understanding that it is in fact a highly organized, integrative, and dynamic regulatory hub. In particular, the subcompartment at the nuclear periphery, comprising the nuclear envelope and the underlying lamina, is now known to be a critical nexus in the regulation of chromatin organization, transcriptional output, biochemical and mechanosignaling pathways, and, more recently, cytoskeletal organization. We review the various functional roles of the nuclear periphery and their deregulation in diseases of the nuclear envelope, specifically the laminopathies, which, despite their rarity, provide insights into contemporary health-care issues.

scholarly journals Chromosome–nuclear envelope tethering – a process that orchestrates homologue pairing during plant meiosis?

2020 ◽  
Vol 133 (15) ◽  
pp. jcs243667
Author(s):  
Adél Sepsi ◽  
Trude Schwarzacher
Keyword(s):  
Nuclear Envelope ◽  
Chromosome Segregation ◽  
Higher Plants ◽  
Nuclear Periphery ◽  
Genetic Material ◽  
Strand Break ◽  
Genome Integrity ◽  
Homologous Chromosomes ◽  
Prophase I ◽  
Plant Meiosis

ABSTRACTDuring prophase I of meiosis, homologous chromosomes pair, synapse and exchange their genetic material through reciprocal homologous recombination, a phenomenon essential for faithful chromosome segregation. Partial sequence identity between non-homologous and heterologous chromosomes can also lead to recombination (ectopic recombination), a highly deleterious process that rapidly compromises genome integrity. To avoid ectopic exchange, homology recognition must be extended from the narrow position of a crossover-competent double-strand break to the entire chromosome. Here, we review advances on chromosome behaviour during meiotic prophase I in higher plants, by integrating centromere- and telomere dynamics driven by cytoskeletal motor proteins, into the processes of homologue pairing, synapsis and recombination. Centromere–centromere associations and the gathering of telomeres at the onset of meiosis at opposite nuclear poles create a spatially organised and restricted nuclear state in which homologous DNA interactions are favoured but ectopic interactions also occur. The release and dispersion of centromeres from the nuclear periphery increases the motility of chromosome arms, allowing meiosis-specific movements that disrupt ectopic interactions. Subsequent expansion of interstitial synapsis from numerous homologous interactions further corrects ectopic interactions. Movement and organisation of chromosomes, thus, evolved to facilitate the pairing process, and can be modulated by distinct stages of chromatin associations at the nuclear envelope and their collective release.

The Role of Caring in Contemporary Health Care

1991 ◽  
Vol 36 (10) ◽  
pp. 871-872
Author(s):  
Linda Baumann
Keyword(s):  
Health Care ◽  
Contemporary Health Care

scholarly journals Revealing Protein-Level Functional Redundancy in the Human Gut Microbiome using Ultra-deep Metaproteomics

2021 ◽  
Author(s):  
Leyuan Li ◽  
Zhibin Ning ◽  
Xu Zhang ◽  
James Butcher ◽  
Caitlin Simopoulos ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Protein Level ◽  
Functional Organization ◽  
Human Microbiome ◽  
Functional Redundancy ◽  
Human Gut ◽  
Functional Roles ◽  
Human Gut Microbiome ◽  
Metagenomics Data ◽  
Network Approaches

Functional redundancy is a key property of ecosystems and represents the fact that phylogenetically unrelated taxa can play similar functional roles within an ecosystem. The redundancy of potential functions of human microbiome has been recently quantified using metagenomics data. Yet, the redundancy of functions which are actually expressed within the human microbiome remains largely unexplored. Here, we quantify the protein-level functional redundancy in the human gut microbiome using metaproteomics and network approaches. In particular, our ultra-deep metaproteomics approach revealed high protein-level functional redundancy and high nestedness in proteomic content networks - bipartite graphs that connect taxa with their expressed functions. We further examined multiple metaproteomics datasets and showed that various environmental factors, including individuality, biogeography, xenobiotics, and disease, significantly altered the protein-level functional redundancy. Finally, by projecting the bipartite proteomic content networks into unipartite weighted genus networks, functional hub genera across individual microbiomes were discovered, suggesting that there may be a universal principle of functional organization in microbiome assembly.

What Can Feminist Epistemology Do for Surgery?

Hypatia ◽  
2014 ◽  
Vol 29 (2) ◽  
pp. 404-421 ◽  
Author(s):  
Mary Jean Walker ◽  
Wendy Rogers
Keyword(s):  
Health Care ◽  
Evidence Base ◽  
Feminist Epistemology ◽  
Cultural Barriers ◽  
Evidence Based ◽  
Surgical Practice ◽  
Lack Of Fit ◽  
What Works ◽  
Based Medicine ◽  
Contemporary Health Care

Surgery is an important part of contemporary health care, but currently much of surgery lacks a strong evidence base. Uptake of evidence‐based medicine (EBM) methods within surgical research and among practitioners has been slow compared with other areas of medicine. Although this is often viewed as arising from practical and cultural barriers, it also reflects a lack of epistemic fit between EBM research methods and surgical practice. In this paper we discuss some epistemic challenges in surgery relating to this lack of fit, and investigate how resources from feminist epistemology can help to characterize them. We point to ways in which these epistemic challenges may be addressed by gathering and disseminating evidence about what works in surgery using methods that are contextual, pluralistic, and sensitive to hierarchies.

Sequential degradation of proteins from the nuclear envelope during apoptosis

2001 ◽  
Vol 114 (20) ◽  
pp. 3643-3653 ◽  
Author(s):  
Madeleine Kihlmark ◽  
Gabriela Imreh ◽  
Einar Hallberg
Keyword(s):  
Nuclear Envelope ◽  
Apoptotic Cell ◽  
Nuclear Periphery ◽  
Condensed Chromatin ◽  
Nuclear Pore ◽  
Dependent Manner ◽  
Nuclear Pores ◽  
Double Labeling ◽  
Lamin B ◽  
Nuclear Apoptosis

We have produced new antibodies specific for the integral pore membrane protein POM121. Using these antibodies we show that during apoptosis POM121 becomes proteolytically degraded in a caspase-dependent manner. The POM121 antibodies and antibodies specific for other proteins of the nuclear envelope were used in a comparative study of nuclear apoptosis in staurosporine-treated buffalo rat liver cells. Nuclei from these cells were classified in three different stages of apoptotic progression: stage I, moderately condensed chromatin surrounded by a smooth nuclear periphery; stage II, compact patches of condensed chromatin collapsing against a smooth nuclear periphery; stage III, round compact chromatin bodies surrounded by grape-shaped nuclear periphery. We have performed double labeling immunofluorescence microscopy of individual apoptotic cells and quantitative immunoblotting analysis of total proteins from apoptotic cell cultures. The results showed that degradation of nuclear envelope marker proteins occurred in a specific order. POM121 degradation occurred surprisingly early and was initiated before nucleosomal DNA degradation could be detected using TUNEL assay and completed before clustering of the nuclear pores. POM121 was eliminated significantly more rapid compared with NUP153 (a peripheral protein located in the nucleoplasmic basket of the nuclear pore complex) and lamin B (a component of the nuclear lamina). Disappearance of NUP153 and lamin B was coincident with onset of DNA fragmentation and clustering of nuclear pores. By contrast, the peripheral NPC protein p62 was degraded much later. The results suggest that degradation of POM121 may be an important early step in propagation of nuclear apoptosis.

scholarly journals Conscientious Objection: A Talmudic Paradigm Shift

2020 ◽  
Vol 59 (2) ◽  
pp. 639-650
Author(s):  
Rabbi Jason Weiner
Keyword(s):  
Health Care ◽  
Paradigm Shift ◽  
Conscientious Objection ◽  
Paradigm Shifting ◽  
Contemporary Health Care

AbstractConscientious objection remains a very heated topic with strong opinions arguing for and against its utilization in contemporary health care. This paper summarizes and analyzes various arguments in the bioethical literature, favoring and opposing conscientious objection, as well as some of the proposed solutions and compromises. I then present a paradigm shifting compromise approach that arises out of very recent Jewish bioethical thought that refocuses the discussion and can minimize the frequency with which conscientious objection is required.

scholarly journals Architecture of the Nuclear Periphery of Rat Pachytene Spermatocytes: Distribution of Nuclear Envelope Proteins in Relation to Synaptonemal Complex Attachment Sites

1999 ◽  
Vol 10 (4) ◽  
pp. 1235-1245 ◽  
Author(s):  
Manfred Alsheimer ◽  
Elisabeth von Glasenapp ◽  
Robert Hock ◽  
Ricardo Benavente
Keyword(s):  
Nuclear Envelope ◽  
Synaptonemal Complex ◽  
Meiotic Prophase ◽  
Nuclear Periphery ◽  
Cell Fractionation ◽  
Nuclear Interior ◽  
Meiotic Chromosomes ◽  
Attachment Sites ◽  
Form Part ◽  
Pachytene Spermatocytes

The nucleus of spermatocytes provides during the first meiotic prophase an interesting model for investigating relationships of the nuclear envelope (NE) with components of the nuclear interior. During the pachytene stage, meiotic chromosomes are synapsed via synaptonemal complexes (SCs) and attached through both ends to the nuclear periphery. This association is dynamic because chromosomes move during the process of synapsis and desynapsis that takes place during meiotic prophase. The NE of spermatocytes possesses some peculiarities (e.g., lower stability than in somatic cells, expression of short meiosis-specific lamin isoforms called C2 and B3) that could be critically involved in this process. For better understanding of the association of chromosomes with the nuclear periphery, in the present study we have investigated the distribution of NE proteins in relation to SC attachment sites. A major outcome was the finding that lamin C2 is distributed in the form of discontinuous domains at the NE of spermatocytes and that SC attachment sites are embedded in these domains. Lamin C2 appears to form part of larger structures as suggested by cell fractionation experiments. According to these results, we propose that the C2-containing domains represent local reinforcements of the NE that are involved in the proper attachment of SCs.

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