Spindle Structures Research Articles

Camillo Golgi's contributions to the anatomic basis of sensitivity in tendons.

Between 1878 and 1880 Camillo Golgi, professor of Histology and General Pathology at the University of Pavia, studied the termination of the nerves inside the tendons, near their muscular insertion. He defined two fundamental categories of corpuscles. The first type, which he called muscle-tendon terminal organs, was morphologically characterized by spindle structures which at one end seemed to relate to the muscle fibers while at the other end they gradually merged with the tendon bundles. Golgi discovered that these structures received from one to four myelinated nerve fibers, which lost their myelin sheath as they entered the bundle, within which they divided dichotically, ending in a large number of terminal arborizations that had the appearance of reticular intertwines. In the superficial thickness of the tendon, near the muscle, Golgi also noticed a second category of corpuscles, which he described as claviform bodies or formations similar to Pacinian bodies. In 1890 Vittorio Mazzoni precisely defined their morphological characteristics. These corpuscles were later called Golgi muscle-tendon organs and Golgi-Mazzoni corpuscles. On the basis of their position and histological appearance, Golgi also correctly hypothesized their physiological role: to be receptors of muscular tension for the muscle-tendon organs and transducers of sensitivity to touch and pressure for the Golgi-Mazzoni corpuscles.

Development Hybrid High-Speed Electro Pneumatic Spindles Drive Unit

Abstract The essence of the research is the search for geometric, material and technological limits of the new concept of spinning spindles. Considering the trend of introducing new generation electric drives into the segment of high-speed spinning spindles (over 120,000 rpm), it is necessary to map and describe the basic physical connections, to find the necessary dependencies and correlations of individual design parameters and their limits for the design of a new generation of spindles. Due to the design limitations of the original and years-used spindle drive concept with a belt and the requirement for the production and development of a new generation of spun fibers, it is necessary to expand the basic knowledge for the design of spindles of the new concept, the design of which will be based on the knowledge and dependencies obtained by measuring and examining the basic principles and determining parameters for the design of spindle structures of a new progressive concept.

Optimized expansion microscopy reveals species-specific spindle microtubule organization in Xenopus egg extracts.

The spindle is a key structure in cell division as it orchestrates the accurate segregation of genetic material. While its assembly and function are well-studied, the mechanisms regulating spindle architecture remain elusive. In this study, we investigate the differences in spindle organization between Xenopus laevis and Xenopus tropicalis, leveraging expansion microscopy (ExM) to overcome the limitations of conventional imaging techniques. We optimized an ExM protocol tailored for Xenopus egg extract spindles, improving upon fixation, denaturation and gelation methods to achieve higher resolution imaging of spindles. Our protocol preserves spindle integrity and allows effective pre-expansion immunofluorescence. This method enabled detailed analysis of the differences in microtubule organization between the two species. X. laevis spindles overall exhibited a broader range of bundle sizes, while X. tropicalis spindles contained mostly smaller bundles. Moreover, while both species exhibited larger bundle sizes near and at the spindle center, X. tropicalis spindles otherwise consisted of very small bundles, and X. laevis spindles medium-sized bundles. By enhancing resolution and minimizing distortions and fixation artifacts, our optimized ExM approach offers new insights into spindle morphology and provides a robust tool for studying the structural intricacies of these large cellular assemblies. This work advances our understanding of spindle architecture and opens up new avenues for exploring underlying mechanisms.

HN1 expression contributes to mitotic fidelity through Aurora A-PLK1-Eg5 axis.

Hematological and neurological expressed 1 (HN1) is homolog of Jupiter protein from Drosophila melanogaster where it functions as a microtubule-associated protein. However, in mammalian cells, HN1 is associated partially with y-tubulin in centrosomes, Stathmin for stabilizing microtubules, and Cdh1 for regulating Cyclin B1 for cell cycle regulation. Moreover, HN1 overexpression leads to early mitotic exit as well. Other molecular functions and interactions of HN1 are not clear yet. Here, based on our previous analysis where HN1 was shown to cluster supernumerary centrosomes and maintain mitotic spindle assembly, we further investigated the role of HN1 in centrosome maintenance and mitotic fidelity in PC-3 prostate and MDA-MB231 mammary cancer cell lines. The maturation-associated roles of HN1 during cell division by examining the AuroraA-PLK1 axis involving a plus end kinesin, Eg5 as well as pericentriolar matrix protein (PCM1) as components of centrosomes were established. We found that HN1 co-localized to centrioles with Eg5 and Aurora A to suppress aberrant spindle formation to ensure the fidelity of centriole/centrosome duplication when overexpressed. Consistently, depleting the HN1 expression using siRNA or shRNA resulted in an increased number of dysregulated mitotic spindle structures, where Aurora A as well as PLK1 co-localizations with Eg5 and PCM1 were disrupted. Further, the PLK1 and Aurora A kinase's phosphorylations also decreased, confirming the hypothesis that the cells struggle in mitotic progression, display nuclear and cytokinetic abnormalities with supernumerary but immature mononucleated centrosomes. In summary, we described the role of HN1 in centrosome nucleation/maturation in PLK1-Eg5 axis and concomitant mitotic spindle formation in human cells.

Correlation of sleep spindle structures and apnea/hypopnea index in adult survivors of childhood Hodgkin lymphoma

Correlation of sleep spindle structures and apnea/hypopnea index in adult survivors of childhood Hodgkin lymphoma

Whole-Mount Immunofluorescence Staining to Visualize Cell Cycle Progression in Mouse Oocyte Meiosis.

Whole-mount immunofluorescence allows direct visualization of the cellular architecture within cells. Here, we apply this technique to mouse oocytes to visualize spindle morphology and microtubule attachments to kinetochores, using a technique we call "cold treatment," at various phases of the meiotic cell cycle. This method allows the analysis of spindle structures at different meiosis I stages and at metaphase II. An adaptation of the protocol to the cell cycle stage of interest is described.

Direct joining of quartz glass and copper by nanosecond laser

In present study, quartz glass and copper, which are with a large difference of coefficient of thermal expansion by 38 times, were successfully welded without any interlayer by nanosecond (ns) laser under non-optical contact for the first time. By reasonably tuning the welding parameters, well-formed quartz glass/copper joints without any defects such as microcracks or voids can be achieved. The welded seam includes laser-unirradiated smooth region and laser-irradiated spindle melted region and both the region are composed of “Cu2O″-SiO2 system (Cu–O–Si system) and CuO. The formation of such a particular microstructure feature is attributed to the recoil pressure from ns laser ablation and the Marangoni convection at the interface. The parameters of ns laser welding including laser power, scanning velocity and the number of scans influence the laser energy input and thermal accumulation greatly during welding, thus affecting the interfacial feature and the mechanical property of the resultant joints. The shear strength of the joint can reach 33.4 MPa, which is about 80% of quartz glass shear strength. The metallurgical bonding from interfacial reaction and mechanical interlocking from physical spindle structures are the main reasons for achieving a high shear strength of the joint. We expect this study could provide a new idea for joining materials with large differences in thermophysical properties.

Investigation of the deterministic value of presence of visible spindle on fertilization and blastocytes utilization potential in frozen/thawed oocyte cycle

Background and Aim: To date, characteristics of the meiotic spindles in human oocytes studied by several authors and shown that they are associated with fertilization, embryo quality, pregnancy and live birth rates. Also, it has been shown that, meiotic spindle structures are very susceptible to cryodamage and can be disassembled and re-assembled depending on the changes in temperature. Thus, studying spindle characteristics of the vitrified-warmed oocytes are important and can provide information regarding the full recovery of the oocytes as well as association with fertilization, embryo development and pregnancy, which the data is limited in literature.

Investigating the Cytotoxicity of Dual-Cure Bulk-Fill Resin Materials on L929 Cells

The aim of this in vitro study was to investigate cytotoxic effects of dual-cure bulk-fill resin materials polymerized with a third-generation LED light-curing unit (LCU) on L929 fibroblast cells in terms of morphology and viability. Three novel dual-cure, flowable bulk-fill materials (Fill-Up!™), a bioactive material (ACTIVA™ BioACTIVE-RESTORATIVE™), and a dual-cure bulk-fill composite material (HyperFIL® HAp) polymerized by LED LCU (VALO™ Cordless) were tested. Each material was placed in plastic rings (4 mm × 5 mm) in a single layer. Unpolymerized rings filled with each material were placed in direct contact with cells and then polymerized. After polymerization, the removed medium was readded to wells. In this study, four control groups were performed: the medium-free control group, medium control group, physical control group, and light applied control group. Three samples were prepared from each group. After 24 h, the morphology of cells was examined and a WST-1 test was performed. The percentage of cell viability (PCV) of each group was calculated. The experiment was repeated three times. Data were analyzed by a Kruskal–Wallis Test and a Mann–Whitney U test. p < 0.05 was considered significant. The PCV of all groups were found to be significantly lower than the medium control group (p < 0.05). The lowest PCV was obtained in HyperFIL® Hap, while highest was in the Fill-Up!™. In the morphology of cells related to the experimental groups, it was observed that the spindle structures of cells were disrupted due to cytotoxicity; cells became rounded and intercellular space increased. There were no significant differences between the control groups (p > 0.05). All control groups showed acceptable PCV (>70%) and cells were spindle-like, similar to the original fibroblast cells. It can be suggested that clinicians should pay attention when applying dual-cure bulk-fill materials in deep cavities, or they should use a liner material under these materials.

P-126 Investigation of the deterministic value of presence of visible spindle on fertilization and blastocytes utilization potential in frozen/thawed oocyte cycle

Abstract Study question Does presence or absence of birefringent spindle after warming of the oocytes has deterministic value on fertilization and early embryonic development potentiaL? Summary answer The warmed oocytes with birefringent spindle seem to have a higher potential to fertilize and become good quality blastocytes. What is known already To date, characteristics of the meiotic spindles in human oocytes were studied by several authors by using a non-invasive method (PolScope) and shown that they are associated with fertilization, embryo quality, pregnancy, and live birth rates. Also, it has been known that meiotic spindle structures are very susceptible to cryodamage and can be disassembled and re-assembled depending on the change in temperature. Thus, studying spindle characteristics of the vitrified-warmed oocytes is important and can provide information about the full recovery of the oocytes, fertilization, embryo development, and pregnancy, which the data is limited in the literature. Study design, size, duration A retrospective study consisting 40 egg donation cycles by using vitrified-warmed oocytes between December 2017 and December 2019 at British Cyprus IVF Hospital. Participants/materials, setting, methods Spindle morphologies of vitrified-warmed oocytes were analyzed by PolScope (RI) combined with an image analysis system after approximately 1.5 hours post-warming. The data is divided into two according to the presence or absence of visible nucleus and correlation with embryonic development analyzed accordingly. To make a comparison in groups a new numerical scoring system for embryo quality on days 5 and 6 was created where embryos scored depending on the stage of expansion, Main results and the role of chance In total, 587 out of 648 vitrified/warmed oocytes survived (90.6%) and 447 of them were fertilized (75.0%). Among the survived oocytes, 503 (85.5%) oocytes were containing detectable spindle (Group I) while spindles were missing in 84 oocytes (Group II). The results showed that the fertilization rate (78.1% vs. 64.3%, p < 0.01), the proportion of good PN morphology (Z Score: Z1 and Z2 over other parameters: 50.4% vs 35.2%, p = 0.036), and viable embryo count (40.6% vs 15.1%, p < 0.01) which is defined as embryos that good enough to transfer or freezing, were higher in group I. Similarly, the degree of expansion on day 5/6 (p = 0.013, p = 0.015 respectively) and the quality of the cells in ICM and TE (p < 0.01) were found higher in group I. We further investigated the differences in embryo quality between groups by converting the embryo grades to numerical value starting from arrested (Score=0) to 6AA (Score=22) and found that embryo scores on day 5 (p = 0.01) and day 6 (p = 0.013) were higher in group I. Limitations, reasons for caution The main limitation of this study is the lack of data regarding the spindle status of the frozen oocytes before vitrification where some of the oocytes might not have visible spindle due to incomplete maturation rather than cryodamage. Wider implications of the findings The present data showed that the presence of birefringent meiotic spindles in warmed oocytes is a very important sign for a full recovery and early embryonic development potential, which can be useful for egg banks and IVF clinics. Trial registration number not applicable

BUBs Are New Biomarkers of Promoting Tumorigenesis and Affecting Prognosis in Breast Cancer.

Background A tumor occurs because of abnormal cell multiplication caused by many variables like a significant disturbance in the regulation of cell growth and the instability of chromosome mitosis. Budding uninhibited by benzimidazoles 1 (BUB1), BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B), and budding uninhibited by benzimidazoles 3 (BUB3) are key regulators of mitosis, and their abnormal expression is highly correlated with breast cancer (BrCa), sarcoma, hepatic carcinoma, and other malignant tumors. However, the occurrence of BUBs (BUB1, BUB1B, and BUB3) and the development of BrCa have not been systematically explained. Methods Find out the target gene by looking up literature on PubMed and CNKI. Using the R software, TCGA, GEO, Kaplan-Meier Plotter, TIMER, and other databases, we studied the level of transcription, genetic changes, and physiological functions of BUBs in BrCa patients and their relationship with the origin, development, prognosis, immunity, and drug resistance of BrCa patients. Findings. We found that the high expression level of BUBs in BrCa tissues proposed a poor prognosis. The multivariate Cox regression analysis suggested that BUB1B and BUB3 might be independent prognostic factors of BrCa. In addition, the Metascape functional enrichment analysis showed that BUBs may be involved in the composition of the spindle, chromosome, and other structures and play a role in mitosis, sister chromatid separation, and other processes. Pathway enrichment suggests that BUBs may affect the cell cycle and lead to abnormal proliferation. Meanwhile, we also found that BUB3 can negatively regulate B lymphocytes, and BUB1 and BUB1B inhibit immune responses by promoting the secretion level of checkpoint molecules of the immune system, leading to immune escape of tumor cells. Conclusion We speculate that BUB1, BUB1B, and BUB3 may be therapeutic targets for BrCa patients and also provide new therapeutic strategies for BrCa treatment.

Theoretical and experimental study of the photodegradation of methyl orange in the presence of different morphologies of Au-ZnO using Monte Carlo dynamic simulation.

Herein, a simple approach was formed based on synthesizing different morphologies of ZnO and Au-ZnO as photocatalyst. In this study, ZnO and Au-ZnO were synthesized via a co-precipitation method and fully characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). Three different ratios of Zn2+:OH- (1:2, 1:3, and 1:5) controlled the morphology of samples, which were made into spindle, star, and flower structures, respectively. Then, the photocatalytic activity was studied and compared. Their comparison showed that the flower morphology for ZnO and Au-ZnO was more effective in photocatalytic degradation and decolorization of methyl orange dye. Also, quantum and Monte Carlo (MC) calculations were carried out to investigate the adsorption of methyl orange (MO) molecules on ZnO(111) surface in the presence of Au or without Au in aqueous conditions by Monte Carlo adsorption locator simulations in the Materials Studio 2017 software. Au created a tendency to form a relatively strong interaction of MO with the ZnO(111) surface. The adsorption of MO on Au-ZnO(111) in the presence of Au was more significant than that of MO on ZnO(111), suggesting Au could significantly improve the reactivity of the methyl orange toward the ZnO(111).

Compartmentalized control of Cdk1 drives mitotic spindle assembly.

During cell division, dramatic microtubular rearrangements driven by cyclin B-cdk1 (Cdk1) kinase activity mark the onset of mitosis leading to dismantling of the interphase microtubular cytoskeleton and assembly of the mitotic spindle. During interphase, Cdk1 accumulates in an inactive state, phosphorylated at inhibitory sites by Wee1/Myt1 kinases. At mitosis onset, Cdc25 phosphatase dephosphorylates and activates Cdk1. Once activated, Cdk1 clears cytoplasmic microtubules by inhibiting microtubule-stabilizing and growth-promoting microtubule-associated proteins (MAPs). Nevertheless, some of these MAPs are required for spindle microtubule growth and spindle assembly, creating quite a conundrum. We show here that a Cdk1 fraction bound to spindle structures escapes Cdc25 action and remains inhibited by phosphorylation (i-Cdk1) in mitotic human cells. Loss or restoration of i-Cdk1 inhibits or promotes spindle assembly, respectively. Furthermore, polymerizing spindle microtubules foster i-Cdk1 aggregating with Wee1 and excluding Cdc25. Our data reveal that spindle assembly relies on compartmentalized control of Cdk1 activity.

Hierarchical spindle structures of Li+-doped ZnO for a high performance humidity sensor

Li+-doped ZnO hierarchical spindle structures have been prepared on FTO conductive glass via a simple hydrothermal synthesis. The sensing performance of the sensor based on Li+-doped ZnO was improved by controlling the Li+ doping concentration.

Acentriolar spindle assembly in mammalian female meiosis and the consequences of its perturbations on human reproduction†.

The purpose of meiosis is to generate developmentally competent, haploid gametes with the correct number of chromosomes. For reasons not completely understood, female meiosis is more prone to chromosome segregation errors than meiosis in males, leading to an abnormal number of chromosomes, or aneuploidy, in gametes. Meiotic spindles are the cellular machinery essential for the proper segregation of chromosomes. One unique feature of spindle structures in female meiosis is spindles poles that lack centrioles. The process of building a meiotic spindle without centrioles is complex and requires precise coordination of different structural components, assembly factors, motor proteins, and signaling molecules at specific times and locations to regulate each step. In this review, we discuss the basics of spindle formation during oocyte meiotic maturation focusing on mouse and human studies. Finally, we review different factors that could alter the process of spindle formation and its stability. We conclude with a discussion of how different assisted reproductive technologies could affect spindles and the consequences these perturbations may have for subsequent embryo development.

Mesoporous rutile TiO2: Synthesis, characterization and photocatalytic performance studies

Pure rutile phase of TiO2(R-TiO2) nanocrystals were synthesized through a low temperature sol-gel synthesis route by tuning the chemical process. This modified process directly resulted in nano spindle structures of rutile TiO2 at the instant of solvent evaporation and which further found exhibiting stabilized growth upon an increase in calcination temperatures as evidenced by XRD and HR-TEM studies. BET surface area measurement revealed the presence of mesoporosity with a highest surface area of 127.25 m2/g for the 300 °C calcinated sample. Photo-luminescence studies revealed the presence of intra-band levels at 2.90 eV and 2.68 eV. XPS studies on the highly porous R-TiO2 reveals the presence of Ti3+ ions, which may arise from the missing of oxygen or self-doping. Highly porous 300ᵒC R-TiO2 exhibited in the flat-band potential of -0.39 V as the normalized value for NHE electrode and resulted in the photocatalytic reduction hierarchy of MB > RhB > MO.

Influence of Calcination Temperature on Size, Morphology and Optical Properties of ZNO/C Composite Synthesized by a Colloidal Method

ZnO is one of the most studied semiconductor materials because of its interesting chemicals, and from a technological point of view, mainly as a consequence of their outstanding properties, such as wurtzite type, non-toxic nature, large band gap, low cost, and environment-friendly. In this work, the ZnO/C composite was synthesized by a simple and fast low-temperature method; the solid product was calcination temperature at 100 to 400 °C. The influence of variation in calcination temperature was studied using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-visible diffuse reflectance spectroscopy. The X-ray diffraction patterns indicated a high crystallinity and a nanocrystalline size of the ZnO/C composite hexagonal structure of wurtzite. The SEM image of the samples showed that the powder has a spherical structure of flakes aggregated in the common nucleus like a grid. The sphere consists of spindle and flower-like structures. The optical properties were determined by UV-vis diffuse reflectance spectroscopy, and it was found that the band gap energy of ZnO/C composite increase from 3.210 to 3.329 eV with an increase in calcination temperature from 100 to 400 °C. FTIR spectra and EDS analysis showed that the existence of carbon in the composite.

High Dosages of Equine Chorionic Gonadotropin Exert Adverse Effects on the Developmental Competence of IVF-Derived Mouse Embryos and Cause Oxidative Stress-Induced Aneuploidy.

Gonadotropins play vital roles in the regulation of female reproductive ability and fertility. Our study aimed to determine the effects of superovulation induced by increasing doses of equine chorionic gonadotropin [eCG; also referred to as pregnant mare serum gonadotropin (PMSG)] on the developmental competence of mouse embryos and on aneuploidy formation during in vitro fertilization (IVF). eCG dose-dependently enhanced the oocyte yield from each mouse. Administration of 15 IU eCG significantly reduced the fertilization rate and the formation of four-cell embryos and blastocysts and increased the risk of chromosome aneuploidy. The IVF-derived blastocysts in the 15 IU eCG treatment group had the fewest total cells, inner cell mass (ICM) cells and trophectoderm (TE) cells. Moreover, more blastocysts and fewer apoptotic cells were observed in the 0, 5, and 10 IU eCG treatment groups than in the 15 IU eCG treatment group. We also investigated reactive oxygen species (ROS) levels and variations in several variables: mitochondrial membrane potential (MMP); active mitochondria; mitochondrial superoxide production; adenosine triphosphate (ATP) content; spindle structures; chromosome karyotypes; microfilament distribution; and the expression of Aurora B [an important component of the chromosomal passenger complex (CPC)], the spindle assembly checkpoint (SAC) protein mitotic arrest deficient 2 like 1 (MAD2L1), and the DNA damage response (DDR) protein γH2AX. Injection of 15 IU eCG increased ROS levels, rapidly reduced MMP, increased active mitochondria numbers and mitochondrial superoxide production, reduced ATP content, increased abnormal spindle formation rates, and induced abnormalities in chromosome number and microfilament distribution, suggesting that a high dose of eCG might alter developmental competence and exert negative effects on IVF-obtained mouse embryos. Additionally, the appearance of γH2AX and the significantly increased expression of Aurora B and MAD2L1 suggested that administration of relatively high doses of eCG caused Aurora B-mediated SAC activation triggered by ROS-induced DNA damage in early mouse IVF-derived embryos for self-correction of aneuploidy formation. These findings improve our understanding of the application of gonadotropins and provide a theoretical basis for gonadotropin treatment.

OUP accepted manuscript

The jet structure of short gamma-ray bursts (GRBs) has been controversial after the detection of GRB 170817A as the electromagnetic counterparts to the gravitational wave event GW170817. Different authors use different jet structures for calculating the afterglow light curves. We formulated a method to inversely reconstruct a jet structure from a given off-axis GRB afterglow, without assuming any functional form of the structure. By systematically applying our inversion method, we find that more diverse jet structures are consistent with the observed afterglow of GRB 170817A within errors: such as hollow-cone, spindle, Gaussian, and power-law jet structures. In addition, the total energy of the reconstructed jet is arbitrary, proportional to the ambient density $n_0$, with keeping the same jet shape if the parameters satisfy the degeneracy combination $n_0 \varepsilon_\mathrm{B}^{(p+1)/(p+5)} \varepsilon_\mathrm{e}^{4(p-1)/(p+5)} = \mathrm{const.}$. Observational accuracy less than $\sim 6$ per cent is necessary to distinguish the different shapes, while the degeneracy of the energy scaling would be broken by observing the spectral breaks and viewing angle. Future events in denser environment with brighter afterglows and observable spectral breaks are ideal for our inversion method to pin down the jet structure, providing the key to the jet formation and propagation.

Compartmentalized Control of Cdk1 Drives Mitotic Spindle Assembly

During cell division, dramatic microtubular rearrangements driven by cyclin B-cdk1 (Cdk1) kinase activity mark mitosis onset leading to interphase cytoskeleton dissolution and mitotic spindle assembly. Once activated by Cdc25, that reverses inhibitory phosphorylation operated by Wee1/Myt1, Cdk1 clears the cytoplasm from microtubules by inhibiting microtubule associated proteins (MAPs) with microtubule growth-promoting properties. Nevertheless, some of these MAPs are required for spindle assembly, creating quite a conundrum. We show here that a Cdk1 fraction bound to spindle structures escaped Cdc25 action and remained inhibited by phosphorylation (i-Cdk1) in mitotic human cells. Loss or restoration of i-Cdk1 inhibited or promoted spindle assembly, respectively. Furthermore, polymerizing spindle microtubules fostered i-Cdk1 by aggregating with Wee1 and excluding Cdc25. Our data reveal that spindle assembly relies on compartmentalized control of Cdk1 activity.