The non-muscle actomyosin cytoskeleton generates contractile force through the dynamic rearrangement of its constituent parts. Actomyosin rings are a specialization of the non-muscle actomyosin cytoskeleton that drive cell shape changes during division, wound healing, and other events. Contractile rings throughout phylogeny and in a range of cellular contexts are built from conserved components including non-muscle myosin II (NMMII), actin filaments (F-actin), and crosslinking proteins.
View Article and Find Full Text PDFClin Pract Cases Emerg Med
November 2023
Introduction: The benign nature of Bell's palsy has led to a lack of a standardized work-up, and dangerous underlying mimics are at risk of being missed.
Case Report: An 84-year-old female with a history of vertigo presented to the emergency department with a left-sided facial droop consistent with Bell's palsy. After further work-up, the patient was diagnosed with bilateral necrotizing mastoiditis.
Septins, a conserved family of filament-forming proteins, contribute to eukaryotic cell division, polarity, and membrane trafficking. Septins scaffold other proteins to cellular membranes, but it is unknown how septins associate with membranes. We identified and characterized an isoform of septin UNC-61 that was predicted to contain a transmembrane domain (TMD).
View Article and Find Full Text PDFDuring zygotic mitosis in many species, forces generated at the cell cortex are required for the separation and migration of paternally provided centrosomes, pronuclear migration, segregation of genetic material, and cell division. Furthermore, in some species, force-generating interactions between spindle microtubules and the cortex position the mitotic spindle asymmetrically within the zygote, an essential step in asymmetric cell division. Understanding the mechanical and molecular mechanisms of microtubule-dependent force generation and therefore asymmetric cell division requires identification of individual cortical force-generating units .
View Article and Find Full Text PDFCrit Care Explor
September 2023
Objectives: We analyzed whether patients with the International Classification of Diseases, 10th Edition (ICD-10) discharge diagnosis code for sepsis are different in regard to demographics and outcome variables when comparing those with sepsis only to those also diagnosed with COVID-19 or those with a COVID-19 diagnosis alone.
Design: Retrospective cohort study.
Setting: Nine hospitals in an academic health system.
End-of-life (EOL) care is a unique area of medicine that emphasizes holistic patient-centered care. It requires clinicians to consider a patients' mental, emotional, spiritual, social and physical comforts and engage patients and their families in complex discussions and decisions. It is an area of medicine that requires sensitivity in communication in order to respond to a wide range of emotions from patients and their families.
View Article and Find Full Text PDFConstriction kinetics of the cytokinetic ring are expected to depend on dynamic adjustment of contractile ring composition, but the impact of ring component abundance dynamics on ring constriction is understudied. Computational models generally assume that contractile networks maintain constant total amounts of components, which is not always true. To test how compositional dynamics affect constriction kinetics, we first measured F-actin, non-muscle myosin II, septin, and anillin during Caenorhabditis elegans zygotic mitosis.
View Article and Find Full Text PDFTo evaluate the effects of state community health worker (CHW) certification programs and Medicaid reimbursement for CHW services on wages and turnover. A staggered difference-in-differences design was used to compare CHWs in states with and without CHW certification or CHW Medicaid reimbursement policies. Data were derived from the 2010 to 2021 Current Population Survey in the United States.
View Article and Find Full Text PDFBackground: The occupation of community health worker (CHW) has evolved to support community member navigation of complex health and social systems. The U.S.
View Article and Find Full Text PDFDeficiency for telomerase results in transgenerational shortening of telomeres. However, telomeres have no known role in transgenerational epigenetic inheritance. C.
View Article and Find Full Text PDFIntrinsic genomic features of individual chromosomes can contribute to chromosome-specific aneuploidy. Centromeres are key elements for the maintenance of chromosome segregation fidelity via a specialized chromatin marked by CENP-A wrapped by repetitive DNA. These long stretches of repetitive DNA vary in length among human chromosomes.
View Article and Find Full Text PDFDuring meiosis, each chromosome must selectively pair and synapse with its own unique homolog to enable crossover formation and subsequent segregation. How homolog pairing is maintained in early meiosis to ensure synapsis occurs exclusively between homologs is unknown. We aimed to further understand this process by examining the meiotic defects of a unique Drosophila mutant, Mcm5A7.
View Article and Find Full Text PDFAcross most sexually reproducing animals, centrosomes are provided to the oocyte through fertilization and must be positioned properly to establish the zygotic mitotic spindle. How centrosomes are positioned in space and time through the concerted action of key mitotic entry biochemical regulators, including protein phosphatase 2A (PP2A-B55/SUR-6), biophysical regulators, including dynein, and the nuclear lamina is unclear. Here, we uncover a role for PP2A-B55/SUR-6 in regulating centrosome separation.
View Article and Find Full Text PDFAs a dividing cell exits mitosis and daughter cells enter interphase, many proteins must be dephosphorylated. The protein phosphatase 2A (PP2A) with its B55 regulatory subunit plays a crucial role in this transition, but the identity of its substrates and how their dephosphorylation promotes mitotic exit are largely unknown. We conducted a maternal-effect screen in to identify genes that function with PP2A-B55/Tws in the cell cycle.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
December 2018
In the last decade, computational processing of big datasets has facilitated the analyses of unprecedented quantities of biological data. Thus, automation and big data analysis have been revolutionary in detecting and quantifying subtle phenotypes in cell biological contexts. Analyzing similar quantities of data in larger and more complicated biological systems such as developing embryos has been more challenging due to experimental limitations on both ensemble data collection and analysis.
View Article and Find Full Text PDFSuccessive cell divisions during embryonic cleavage create increasingly smaller cells, so intracellular structures must adapt accordingly. Mitotic spindle size correlates with cell size, but the mechanisms for this scaling remain unclear. Using live cell imaging, we analyzed spindle scaling during embryo cleavage in the nematode Caenorhabditis elegans and sea urchin Paracentrotus lividus.
View Article and Find Full Text PDFThe spindle assembly checkpoint (SAC) is a conserved mitotic regulator that preserves genome stability by monitoring kinetochore-microtubule attachments and blocking anaphase onset until chromosome biorientation is achieved. Despite its central role in maintaining mitotic fidelity, the ability of the SAC to delay mitotic exit in the presence of kinetochore-microtubule attachment defects (SAC "strength") appears to vary widely. How different cellular aspects drive this variation remains largely unknown.
View Article and Find Full Text PDFFluorescence microscopy is a powerful approach for studying subcellular dynamics at high spatiotemporal resolution; however, conventional fluorescence microscopy techniques are light-intensive and introduce unnecessary photodamage. Light-sheet fluorescence microscopy (LSFM) mitigates these problems by selectively illuminating the focal plane of the detection objective by using orthogonal excitation. Orthogonal excitation requires geometries that physically limit the detection objective numerical aperture (NA), thereby limiting both light-gathering efficiency (brightness) and native spatial resolution.
View Article and Find Full Text PDFCell shape changes such as cytokinesis are driven by the actomyosin contractile cytoskeleton. The molecular rearrangements that bring about contractility in nonmuscle cells are currently debated. Specifically, both filament sliding by myosin motors, as well as cytoskeletal cross-linking by myosins and nonmotor cross-linkers, are thought to promote contractility.
View Article and Find Full Text PDFIodixanol provides an easy and affordable solution to a problem that has limited resolution and brightness when imaging living samples.
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