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Journal articles on the topic 'Sperm Cell Focusing Dynamics'

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Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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1

Tourzani, Darya A., Qiangzong Yin, Erica A. Jackson, Oliver J. Rando, Pablo E. Visconti, and Maria G. Gervasi. "Sperm Energy Restriction and Recovery (SER) Alters Epigenetic Marks during the First Cell Cycle of Development in Mice." International Journal of Molecular Sciences 24, no. 1 (December 30, 2022): 640. http://dx.doi.org/10.3390/ijms24010640.

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The sperm energy restriction and recovery (SER) treatment developed in our laboratory was shown to improve fertilization and blastocyst development following in vitro fertilization (IVF) in mice. Here, we investigated the effects of SER on early embryogenesis. Developmental events observed during the first cell cycle indicated that progression through the pronuclear stages of SER-generated embryos is advanced in comparison with control-generated embryos. These findings prompted further analysis of potential effects of SER on pronuclear chromatin dynamics, focusing on the key H3K4me3 and H3K27ac histone modifications. Nearly all the SER-generated embryos displayed H3K4me3 in the male pronuclei at 12 h post-insemination (HPI), while a subset of the control-generated embryos did not. Additionally, SER-generated embryos displayed a more homogenous intensity of H3K27ac at 8 and 12 HPI compared to control embryos. These changes in histone modifications during the first cell cycle were accompanied by differences in gene expression at the two-cell stage; both of these changes in early embryos could potentially play a role in the improved developmental outcomes of these embryos later in development. Our results indicate that sperm incubation conditions have an impact on early embryo development and can be useful for the improvement of assisted reproductive technology outcomes.
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2

Horne-Badovinac, Sally. "The Drosophila micropyle as a system to study how epithelia build complex extracellular structures." Philosophical Transactions of the Royal Society B: Biological Sciences 375, no. 1809 (August 24, 2020): 20190561. http://dx.doi.org/10.1098/rstb.2019.0561.

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Dynamic rearrangements of epithelial cells play central roles in shaping tissues and organs during development. There are also scenarios, however, in which epithelial cell movements synergize with the secretion of extracellular matrix to build rigid, acellular structures that persist long after the cells are gone. The formation of the Drosophila micropyle provides an elegant example of this epithelial craftsmanship. The micropyle is a cone-shaped projection of the eggshell through which the sperm will enter to fertilize the oocyte. Though simple on the surface, both the inner structure and construction of the micropyle are remarkably complex. In this review, I first provide an overview of egg development, focusing on the key events required to understand micropyle formation. I then describe the structure of the micropyle, the cellular contributions to its morphogenesis and some interesting open questions about this process. There is a brief discussion of micropyle formation in other insects and fish to highlight the potential for comparative studies. Finally, I discuss how new studies of micropyle formation could reveal general mechanisms that epithelia use to build complex extracellular structures. This article is part of a discussion meeting issue ‘Contemporary morphogenesis'.
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3

Hamamura, Yuki. "Double fertilization mechanism as suggested by sperm cell dynamics." PLANT MORPHOLOGY 24, no. 1 (2012): 97–103. http://dx.doi.org/10.5685/plmorphol.24.97.

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4

Wolf, D. E., C. A. McKinnon, L. Leyton, K. Lakoski Loveland, and P. M. Saling. "Protein dynamics in sperm membranes: Implications for sperm function during gamete interaction." Molecular Reproduction and Development 33, no. 2 (October 1992): 228–34. http://dx.doi.org/10.1002/mrd.1080330217.

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5

Gadella, B. M., T. W. Gadella, B. Colenbrander, L. M. van Golde, and M. Lopes-Cardozo. "Visualization and quantification of glycolipid polarity dynamics in the plasma membrane of the mammalian spermatozoon." Journal of Cell Science 107, no. 8 (August 1, 1994): 2151–63. http://dx.doi.org/10.1242/jcs.107.8.2151.

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Seminolipid (sulphogalactosylalkylacylglycerol), the glycolipid that is specific for mammalian germ cells, is located exclusively in the outer leaflet of the sperm plasma membrane. In this study the lateral distribution of seminolipid on sperm heads has been investigated by indirect immunofluorescence labelling and detection with digital imaging fluorescence microscopy. In freshly ejaculated sperm cells this glycolipid was present primarily at the apical ridge subdomain of the plasma membrane of the sperm head. After binding the sperm cells to zona-coated coverslips seminolipid migrated, in 40 minutes, from the apical ridge to the equatorial subdomain of the plasma membrane. A similar redistribution of seminolipid was observed during capacitation of sperm cells in vitro induced by Ca2+ or bovine serum albumin. Comparable migration of seminolipid was also found after prolonged storage of ejaculated sperm cells, albeit at a much slower rate. Addition of arylsulphatase A, an enzyme present in seminal plasma that desulphates seminolipid, significantly enhanced the migration of seminolipid during storage of sperm cells. Its breakdown product desulphoseminolipid (galactosylalkylacylglycerol) appeared highly specifically at the equatorial segment. The measured fluorescence intensity over the sperm head surface correlated linearly with the spatial probe distribution as was checked by fluorescence lifetime imaging microscopy. This paper demonstrates and quantifies for the first time the polarity of seminolipid on the surface of the sperm cell and the dynamic alterations that occur in this polarity during post-ejaculatory events.
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6

Verhage, Leonie. "Find your identity – methylation dynamics in the sperm cell lineage." Plant Journal 105, no. 3 (February 2021): 563–64. http://dx.doi.org/10.1111/tpj.15155.

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7

Gadella, Barend M., and Carolina Luna. "Cell biology and functional dynamics of the mammalian sperm surface." Theriogenology 81, no. 1 (January 2014): 74–84. http://dx.doi.org/10.1016/j.theriogenology.2013.09.005.

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8

Fice, Heather, and Bernard Robaire. "Telomere Dynamics Throughout Spermatogenesis." Genes 10, no. 7 (July 12, 2019): 525. http://dx.doi.org/10.3390/genes10070525.

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Telomeres are repeat regions of DNA that cap either end of each chromosome, thereby providing stability and protection from the degradation of gene-rich regions. Each cell replication causes the loss of telomeric repeats due to incomplete DNA replication, though it is well-established that progressive telomere shortening is evaded in male germ cells by the maintenance of active telomerase. However, germ cell telomeres are still susceptible to disruption or insult by oxidative stress, toxicant exposure, and aging. Our aim was to examine the relative telomere length (rTL) in an outbred Sprague Dawley (SD) and an inbred Brown Norway (BN) rat model for paternal aging. No significant differences were found when comparing pachytene spermatocytes (PS), round spermatids (RS), and sperm obtained from the caput and cauda of the epididymis of young and aged SD rats; this is likely due to the high variance observed among individuals. A significant age-dependent decrease in rTL was observed from 115.6 (±6.5) to 93.3 (±6.3) in caput sperm and from 142.4 (±14.6) to 105.3 (±2.5) in cauda sperm from BN rats. Additionally, an increase in rTL during epididymal maturation was observed in both strains, most strikingly from 115.6 (±6.5) to 142 (±14.6) in young BN rats. These results confirm the decrease in rTL in rodents, but only when an inbred strain is used, and represent the first demonstration that rTL changes as sperm transit through the epididymis.
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9

Subramani, Elavarasan, Himanish Basu, Shyam Thangaraju, Sucheta Dandekar, Deepak Mathur, and Koel Chaudhury. "Rotational Dynamics of Optically Trapped Human Spermatozoa." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/154367.

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Introduction. Optical trapping is a laser-based method for probing the physiological and mechanical properties of cells in a noninvasive manner. As sperm motility is an important criterion for assessing the male fertility potential, this technique is used to study sperm cell motility behavior and rotational dynamics.Methods and Patients. An integrated optical system with near-infrared laser beam has been used to analyze rotational dynamics of live sperm cells from oligozoospermic and asthenozoospermic cases and compared with controls.Results. The linear, translational motion of the sperm is converted into rotational motion on being optically trapped, without causing any adverse effect on spermatozoa. The rotational speed of sperm cells from infertile men is observed to be significantly less as compared to controls.Conclusions. Distinguishing normal and abnormal sperm cells on the basis of beat frequency above 5.6 Hz may be an important step in modern reproductive biology to sort and select good quality spermatozoa. The application of laser-assisted technique in biology has the potential to be a valuable tool for assessment of sperm fertilization capacity for improving assisted reproductive technology.
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10

Llanses Martinez, Montserrat, and Elena Rainero. "Membrane dynamics in cell migration." Essays in Biochemistry 63, no. 5 (July 26, 2019): 469–82. http://dx.doi.org/10.1042/ebc20190014.

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Abstract Migration of cells is required in multiple tissue-level processes, such as in inflammation or cancer metastasis. Endocytosis is an extremely regulated cellular process by which cells uptake extracellular molecules or internalise cell surface receptors. While the role of endocytosis of focal adhesions (FA) and plasma membrane (PM) turnover at the leading edge of migratory cells is wide known, the contribution of endocytic proteins per se in migration has been frequently disregarded. In this review, we describe the novel functions of the most well-known endocytic proteins in cancer cell migration, focusing on clathrin, caveolin, flotillins and GRAF1. In addition, we highlight the relevance of the macropinocytic pathway in amoeboid-like cell migration.
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11

Ramón, Manuel, M. Dolores Pérez-Guzmán, Pilar Jiménez-Rabadán, Milagros C. Esteso, Olga García-Álvarez, Alejandro Maroto-Morales, Luis Anel-López, Ana J. Soler, M. Rocío Fernández-Santos, and J. Julián Garde. "Sperm Cell Population Dynamics in Ram Semen during the Cryopreservation Process." PLoS ONE 8, no. 3 (March 27, 2013): e59189. http://dx.doi.org/10.1371/journal.pone.0059189.

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12

Ishijima, Sumio. "Dynamics of flagellar force generated by a hyperactivated spermatozoon." REPRODUCTION 142, no. 3 (September 2011): 409–15. http://dx.doi.org/10.1530/rep-10-0445.

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The flagellar force generated by a hyperactivated monkey spermatozoon was evaluated using the resistive force theory applied to the activated (nonhyperactivated) and hyperactivated flagellar waves that were obtained using high-speed video microscopy and digital image processing in order to clarify the mechanism of sperm penetration through the zona pellucida. No difference in the maximum propulsive force, which was parallel to the longitudinal sperm head axis, was found between the activated and hyperactivated spermatozoa. The maximum transverse force (45 pN), which was perpendicular to the longitudinal sperm head axis, of the hyperactivated spermatozoon was ∼2.5 times its propulsive force. As the beat frequency of the flagellar beating remarkably decreased during the hyperactivation, the slowly oscillating transverse force (5 Hz) by the hyperactivated spermatozoon seems to be most effective for sperm penetration through the zona pellucida.
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13

Gamper, Ivonne, David Fleck, Meltem Barlin, Marc Spehr, Sara El Sayad, Henning Kleine, Sebastian Maxeiner, et al. "GAR22β regulates cell migration, sperm motility, and axoneme structure." Molecular Biology of the Cell 27, no. 2 (January 15, 2016): 277–94. http://dx.doi.org/10.1091/mbc.e15-06-0426.

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Spatiotemporal cytoskeleton remodeling is pivotal for cell adhesion and migration. Here we investigated the function of Gas2-related protein on chromosome 22 (GAR22β), a poorly characterized protein that interacts with actin and microtubules. Primary and immortalized GAR22β−/− Sertoli cells moved faster than wild-type cells. In addition, GAR22β−/− cells showed a more prominent focal adhesion turnover. GAR22β overexpression or its reexpression in GAR22β−/− cells reduced cell motility and focal adhesion turnover. GAR22β–actin interaction was stronger than GAR22β–microtubule interaction, resulting in GAR22β localization and dynamics that mirrored those of the actin cytoskeleton. Mechanistically, GAR22β interacted with the regulator of microtubule dynamics end-binding protein 1 (EB1) via a novel noncanonical amino acid sequence, and this GAR22β–EB1 interaction was required for the ability of GAR22β to modulate cell motility. We found that GAR22β is highly expressed in mouse testes, and its absence resulted in reduced spermatozoa generation, lower actin levels in testes, and impaired motility and ultrastructural disorganization of spermatozoa. Collectively our findings identify GAR22β as a novel regulator of cell adhesion and migration and provide a foundation for understanding the molecular basis of diverse cytoskeleton-dependent processes.
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14

Gadêlha, H., E. A. Gaffney, D. J. Smith, and J. C. Kirkman-Brown. "Nonlinear instability in flagellar dynamics: a novel modulation mechanism in sperm migration?" Journal of The Royal Society Interface 7, no. 53 (May 12, 2010): 1689–97. http://dx.doi.org/10.1098/rsif.2010.0136.

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Throughout biology, cells and organisms use flagella and cilia to propel fluid and achieve motility. The beating of these organelles, and the corresponding ability to sense, respond to and modulate this beat is central to many processes in health and disease. While the mechanics of flagellum–fluid interaction has been the subject of extensive mathematical studies, these models have been restricted to being geometrically linear or weakly nonlinear, despite the high curvatures observed physiologically. We study the effect of geometrical nonlinearity, focusing on the spermatozoon flagellum. For a wide range of physiologically relevant parameters, the nonlinear model predicts that flagellar compression by the internal forces initiates an effective buckling behaviour, leading to a symmetry-breaking bifurcation that causes profound and complicated changes in the waveform and swimming trajectory, as well as the breakdown of the linear theory. The emergent waveform also induces curved swimming in an otherwise symmetric system, with the swimming trajectory being sensitive to head shape—no signalling or asymmetric forces are required. We conclude that nonlinear models are essential in understanding the flagellar waveform in migratory human sperm; these models will also be invaluable in understanding motile flagella and cilia in other systems.
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15

Losano, João Diego de Agostini, Daniel de Souza Ramos Angrimani, Roberta Ferreira Leite, Bárbara do Carmo Simões da Silva, Valquíria Hyppolito Barnabe, and Marcilio Nichi. "Spermatic mitochondria: role in oxidative homeostasis, sperm function and possible tools for their assessment." Zygote 26, no. 4 (August 2018): 251–60. http://dx.doi.org/10.1017/s0967199418000242.

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SummaryDespite sperm mitochondrial relevance to the fertilization capacity, the processes involved in the production of ATP and functional dynamics of sperm mitochondria are not fully understood. One of these processes is the paradox involved between function and formation of reactive oxygen species performed by the organelle. Therefore, this review aimed to provide data on the role of sperm mitochondria in oxidative homeostasis and functionality as well the tools to assess sperm mitochondrial function.
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16

Bozzini, Benedetto, Danjela Kuscer, Matteo Amati, Luca Gregoratti, Patrick Zeller, Tsvetina Dobrovolska, and Ivan Krastev. "Spatially Resolved XPS Characterization of Electrochemical Surfaces." Surfaces 2, no. 2 (April 15, 2019): 295–314. http://dx.doi.org/10.3390/surfaces2020022.

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Synchrotron-based scanning photoelectron microscopy (SPEM) has opened unique opportunities for exploiting processes occurring at surfaces and interfaces, which control the properties of materials for electrochemical devices, where issues of chemical and morphological complexity at microscopic length scales should be faced and understood. The present article aims to demonstrate the present capabilities of SPEM to explore the surface composition of micro- and nano-structured materials, focusing on cases relevant to electrochemical technologies. We report and discuss a selection of recent results about three different systems, targeting hot topics in the fields of electrochemical energy storage and electrochemical fabrication: (i) an in-depth analysis of Ag-In electrodeposited alloys exhibiting dynamic pattern formation, (ii) the analysis of electrochemical processes at the electrodes of a self-driven solid oxide fuel cell and (iii) an operando characterization of a single-chamber solid oxide fuel cell. The last example has been performed at near-ambient pressure conditions using a unique specially designed setup which extends the traditional capabilities of scanning photoemission microscopes in the ultra-high and high-vacuum regimes to operating conditions that are closer to realistic ones, contributing to overcome the so-called “pressure gap”.
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17

Tahara, M., K. Tasaka, N. Masumoto, A. Mammoto, Y. Ikebuchi, and A. Miyake. "Dynamics of cortical granule exocytosis at fertilization in living mouse eggs." American Journal of Physiology-Cell Physiology 270, no. 5 (May 1, 1996): C1354—C1361. http://dx.doi.org/10.1152/ajpcell.1996.270.5.c1354.

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Sperm-egg fusion induces an intracellular free calcium concentration ([Ca2+]i) increase and exocytosis of cortical granules (CGs). Recently we used an impermeable fluorescent membrane probe, 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), to develop a method to evaluate the kinetics of exocytosis in single living cells. In this study we used digital imaging and confocal laser scanning microscopy to evaluate CG exocytosis in living mouse eggs with TMA-DPH. Time-related changes of CG exocytosis were estimated as the percent increase of TMA-DPH fluorescence. The increase of fluorescence in the egg started after sperm attachment, continued at an almost uniform rate, and ceased at 45-60 min. Whereas the [Ca2+]i increase at fertilization was transient or oscillatory, exocytosis was not always induced concomitantly with each [Ca2+]i peak. Next we used this method to determine some intracellular mediators of exocytosis in the egg. An intracellular calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, and a microfilament inhibitor, cytochalasin B, blocked sperm-induced exocytosis. A guanosine 5'-triphosphate-binding protein activator, AlF4-, induced exocytosis. These results suggest that [Ca2+]i, microfilament, and guanosine 5'-triphosphate-binding proteins may be involved in CG exocytosis. In conclusion, this method has significant advantages for studying exocytosis in living eggs.
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18

Varuzhanyan, Grigor, and David C. Chan. "Mitochondrial dynamics during spermatogenesis." Journal of Cell Science 133, no. 14 (July 15, 2020): jcs235937. http://dx.doi.org/10.1242/jcs.235937.

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ABSTRACTMitochondrial fusion and fission (mitochondrial dynamics) are homeostatic processes that safeguard normal cellular function. This relationship is especially strong in tissues with constitutively high energy demands, such as brain, heart and skeletal muscle. Less is known about the role of mitochondrial dynamics in developmental systems that involve changes in metabolic function. One such system is spermatogenesis. The first mitochondrial dynamics gene, Fuzzy onions (Fzo), was discovered in 1997 to mediate mitochondrial fusion during Drosophila spermatogenesis. In mammals, however, the role of mitochondrial fusion during spermatogenesis remained unknown for nearly two decades after discovery of Fzo. Mammalian spermatogenesis is one of the most complex and lengthy differentiation processes in biology, transforming spermatogonial stem cells into highly specialized sperm cells over a 5-week period. This elaborate differentiation process requires several developmentally regulated mitochondrial and metabolic transitions, making it an attractive model system for studying mitochondrial dynamics in vivo. We review the emerging role of mitochondrial biology, and especially its dynamics, during the development of the male germ line.
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19

Buttery, Shawnna M., Gail C. Ekman, Margaret Seavy, Murray Stewart, and Thomas M. Roberts. "Dissection of the Ascaris Sperm Motility Machinery Identifies Key Proteins Involved in Major Sperm Protein-based Amoeboid Locomotion." Molecular Biology of the Cell 14, no. 12 (December 2003): 5082–88. http://dx.doi.org/10.1091/mbc.e03-04-0246.

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Although Ascaris sperm motility closely resembles that seen in many other types of crawling cells, the lamellipodial dynamics that drive movement result from modulation of a cytoskeleton based on the major sperm protein (MSP) rather than actin. The dynamics of the Ascaris sperm cytoskeleton can be studied in a cell-free in vitro system based on the movement of plasma membrane vesicles by fibers constructed from bundles of MSP filaments. In addition to ATP, MSP, and a plasma membrane protein, reconstitution of MSP motility in this cell-free extract requires cytosolic proteins that orchestrate the site-specific assembly and bundling of MSP filaments that generates locomotion. Here, we identify a fraction of cytosol that is comprised of a small number of proteins but contains all of the soluble components required to assemble fibers. We have purified two of these proteins, designated MSP fiber proteins (MFPs) 1 and 2 and demonstrated by immunolabeling that both are located in the MSP cytoskeleton in cells and in fibers. These proteins had reciprocal effects on fiber assembly in vitro: MFP1 decreased the rate of fiber growth, whereas MFP2 increased the growth rate.
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20

Flesch, Frits M., and Barend M. Gadella. "Dynamics of the mammalian sperm plasma membrane in the process of fertilization." Biochimica et Biophysica Acta (BBA) - Reviews on Biomembranes 1469, no. 3 (November 2000): 197–235. http://dx.doi.org/10.1016/s0304-4157(00)00018-6.

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21

Sostaric, Edita, Chris H. A. van de Lest, Ben Colenbrander, and Bart M. Gadella. "Dynamics of Carbohydrate Affinities at the Cell Surface of Capacitating Bovine Sperm Cells." Biology of Reproduction 72, no. 2 (February 1, 2005): 346–57. http://dx.doi.org/10.1095/biolreprod.104.029330.

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22

Veitinger, Thomas, Jeffrey R. Riffell, Sophie Veitinger, Jaclyn M. Nascimento, Annika Triller, Charlie Chandsawangbhuwana, Katlen Schwane, et al. "Chemosensory Ca2+Dynamics Correlate with Diverse Behavioral Phenotypes in Human Sperm." Journal of Biological Chemistry 286, no. 19 (March 21, 2011): 17311–25. http://dx.doi.org/10.1074/jbc.m110.211524.

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23

Bellve, A. R., R. Chandrika, and A. Barth. "Temporal expression, polar distribution and transition of an epitope domain in the perinuclear theca during mouse spermatogenesis." Journal of Cell Science 96, no. 4 (August 1, 1990): 745–56. http://dx.doi.org/10.1242/jcs.96.4.745.

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A novel domain of epitopes is expressed by a family of high-Mr proteins at the anterior pole of the germ cell nucleus during spermiogenesis, and later by two low-Mr proteins at the anterior and posterior poles of the nucleus during sperm maturation in the epididymis. Initially, monoclonal antibodies (mAbs) PNT-1 (IgG2b) and PNT-2 (IgG2a) bound to antigens present in a cap-like configuration at the apical pole of the spermatid nucleus at step 5 of spermiogenesis. The distribution of epitopes on the nucleus expanded posteriorly until, in testicular sperm they covered the anterior pole down to the distal limits of the subacrosomal perforatorium. By contrast, sperm from the epididymis and vas deferens bound both mAbs in two distinct regions on the nucleus, one on the dorsal margin of the anterior pole, and the other in a ventral zone at the posterior pole. On SDS-PAGE and isoelectric focusing (IEF) immunoblots, both mAbs bound three major proteins with Mr of approximately 80,000, 77,000 and 75,000 from spermatids and testicular sperm, and proteins of Mr 50,000 and 48,000 in epididymal and vas deferens sperm. Both the high- and low-Mr protein families were recovered in germ cell nuclear/perinuclear matrices. Their mobilities on SDS-PAGE were not altered by exo- or endoglycosidases or by aminoethylation in denaturing conditions. mAb PNT-1 bound to the sperm proteins with a Ka of 3.53 × 10(12) M-1 and mAb PNT-2 with a Ka of 2.08 × 10(12) M-1. From competition binding data, mAbs PNT-1 to -10 appeared to recognize six adjacent or overlapping epitopes on the same proteins. These data suggest the high-Mr proteins, the thecins, present at the anterior pole of haploid germ cells are processed at the onset of sperm maturation to yield two low-Mr proteins that then occupy two distinct domains at the anterior and posterior poles of the nucleus.
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24

Firman, Renée C. "Of mice and women: advances in mammalian sperm competition with a focus on the female perspective." Philosophical Transactions of the Royal Society B: Biological Sciences 375, no. 1813 (October 19, 2020): 20200082. http://dx.doi.org/10.1098/rstb.2020.0082.

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Although initially lagging behind discoveries being made in other taxa, mammalian sperm competition is now a productive and advancing field of research. Sperm competition in mammals is not merely a ‘sprint-race’ between the gametes of rival males, but rather a race over hurdles; those hurdles being the anatomical and physiological barriers provided by the female reproductive tract, as well as the egg and its vestments. With this in mind, in this review, I discuss progress in the field while focusing on the female perspective. I highlight ways by which sperm competition can have positive effects on female reproductive success and discuss how competitive outcomes are not only owing to dynamics between the ejaculates of rival males, but also attributable to mechanisms by which female mammals bias paternity toward favourable sires. Drawing on examples across different species—from mice to humans—I provide an overview of the accumulated evidence which firmly establishes that sperm competition is a key selective force in the evolution of male traits and detail how females can respond to increased sperm competitiveness with increased egg resistance to fertilization. I also discuss evidence for facultative responses to the sperm competition environment observed within mammal species. Overall, this review identifies shortcomings in our understanding of the specific mechanisms by which female mammals ‘select’ sperm. More generally, this review demonstrates how, moving forward, mammals will continue to be effective animal models for studying both evolutionary and facultative responses to sperm competition. This article is part of the theme issue ‘Fifty years of sperm competition’.
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25

Gadella, B. M., F. M. Flesch, L. M. G. van Golde, and B. Colenbrander. "Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization." Veterinary Quarterly 21, no. 4 (October 1999): 142–46. http://dx.doi.org/10.1080/01652176.1999.9695009.

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26

Gozes, Illana, Yanina Ivashko-Pachima, Oxana Kapitansky, Carmen Laura Sayas, and Tal Iram. "Single-cell analysis of cytoskeleton dynamics: From isoelectric focusing to live cell imaging and RNA-seq." Journal of Neuroscience Methods 323 (July 2019): 119–24. http://dx.doi.org/10.1016/j.jneumeth.2019.05.014.

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27

Schoeller, Simon F., and Eric E. Keaveny. "From flagellar undulations to collective motion: predicting the dynamics of sperm suspensions." Journal of The Royal Society Interface 15, no. 140 (March 2018): 20170834. http://dx.doi.org/10.1098/rsif.2017.0834.

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Swimming cells and microorganisms are as diverse in their collective dynamics as they are in their individual shapes and propulsion mechanisms. Even for sperm cells, which have a stereotyped shape consisting of a cell body connected to a flexible flagellum, a wide range of collective dynamics is observed spanning from the formation of tightly packed groups to the display of larger-scale, turbulence-like motion. Using a detailed mathematical model that resolves flagellum dynamics, we perform simulations of sperm suspensions containing up to 1000 cells and explore the connection between individual and collective dynamics. We find that depending on the level of variation in individual dynamics from one swimmer to another, the sperm exhibit either a strong tendency to aggregate, or the suspension exhibits large-scale swirling. Hydrodynamic interactions govern the formation and evolution of both states. In addition, a quantitative analysis of the states reveals that the flows generated at the time scale of flagellum undulations contribute significantly to the overall energy in the surrounding fluid, highlighting the importance of resolving these flows.
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28

Meaders, Johnathan L., and David R. Burgess. "Microtubule-Based Mechanisms of Pronuclear Positioning." Cells 9, no. 2 (February 23, 2020): 505. http://dx.doi.org/10.3390/cells9020505.

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The zygote is defined as a diploid cell resulting from the fusion of two haploid gametes. Union of haploid male and female pronuclei in many animals occurs through rearrangements of the microtubule cytoskeleton into a radial array of microtubules known as the sperm aster. The sperm aster nucleates from paternally-derived centrioles attached to the male pronucleus after fertilization. Nematode, echinoderm, and amphibian eggs have proven as invaluable models to investigate the biophysical principles for how the sperm aster unites male and female pronuclei with precise spatial and temporal regulation. In this review, we compare these model organisms, discussing the dynamics of sperm aster formation and the different force generating mechanism for sperm aster and pronuclear migration. Finally, we provide new mechanistic insights for how sperm aster growth may influence sperm aster positioning.
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29

Bukatin, Anton, Igor Kukhtevich, Norbert Stoop, Jörn Dunkel, and Vasily Kantsler. "Bimodal rheotactic behavior reflects flagellar beat asymmetry in human sperm cells." Proceedings of the National Academy of Sciences 112, no. 52 (December 10, 2015): 15904–9. http://dx.doi.org/10.1073/pnas.1515159112.

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Rheotaxis, the directed response to fluid velocity gradients, has been shown to facilitate stable upstream swimming of mammalian sperm cells along solid surfaces, suggesting a robust physical mechanism for long-distance navigation during fertilization. However, the dynamics by which a human sperm orients itself relative to an ambient flow is poorly understood. Here, we combine microfluidic experiments with mathematical modeling and 3D flagellar beat reconstruction to quantify the response of individual sperm cells in time-varying flow fields. Single-cell tracking reveals two kinematically distinct swimming states that entail opposite turning behaviors under flow reversal. We constrain an effective 2D model for the turning dynamics through systematic large-scale parameter scans, and find good quantitative agreement with experiments at different shear rates and viscosities. Using a 3D reconstruction algorithm to identify the flagellar beat patterns causing left or right turning, we present comprehensive 3D data demonstrating the rolling dynamics of freely swimming sperm cells around their longitudinal axis. Contrary to current beliefs, this 3D analysis uncovers ambidextrous flagellar waveforms and shows that the cell’s turning direction is not defined by the rolling direction. Instead, the different rheotactic turning behaviors are linked to a broken mirror symmetry in the midpiece section, likely arising from a buckling instability. These results challenge current theoretical models of sperm locomotion.
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Tomás, C., E. Blanch, A. Fazeli, and E. Mocé. "Effect of a pre-freezing treatment with cholesterol-loaded cyclodextrins on boar sperm longevity, capacitation dynamics, ability to adhere to porcine oviductal epithelial cells in vitro and DNA fragmentation dynamics." Reproduction, Fertility and Development 25, no. 6 (2013): 935. http://dx.doi.org/10.1071/rd12079.

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The aim of this work was to examine how a pre-freezing treatment with cholesterol-loaded cyclodextrins (CLC) affects boar sperm longevity, capacitation dynamics, ability to bind to a porcine telomerase-immortalised oviductal epithelial cell line (TERT-OPEC) in vitro and DNA integrity dynamics after freeze–thawing. Although the samples treated with CLC exhibited lower sperm quality than the control samples (P < 0.05) immediately after thawing, these differences disappeared (P > 0.05) after long-term incubation (26 h at 37 or 16°C). Additionally, the CLC-treated spermatozoa underwent similar capacitation and DNA fragmentation dynamics as the control spermatozoa (P > 0.05). However, CLC-treated spermatozoa were better able to bind to TERT-OPEC in vitro (P < 0.0001). In conclusion, the pre-freezing treatment of boar spermatozoa with CLC enhanced the ability of the spermatozoa to bind to TERT-OPEC in vitro, which could have an effect on the establishment of the sperm reservoir in the ampullary­–isthmic junction in vivo. Additionally, frozen–thawed spermatozoa can be stored at 16°C for at least 6 h without a significant observable decline in sperm quality, which could be beneficial for the transport of thawed diluted doses of spermatozoa from the laboratory to the farm.
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31

Anand-Ivell, Ravinder, and Richard Ivell. "The special systems biology of the sperm." Biochemical Journal 436, no. 3 (May 27, 2011): e3-e5. http://dx.doi.org/10.1042/bj20110766.

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Spermatozoa represent a highly specialized cell type, with a minimalist structure designed to fulfil a single principal function: the transport of an intact single-copy haploid genome to the site of fertilization in the oviduct, and consequent zygote formation. They have lost most of their original cytoplasm, and remaining organelles are extremely modified. One result of this is that biochemical dynamics are restricted by a lack of cytoplasmic diffusion and a dramatic compartmentalization, with an increased emphasis on the physicochemical modulation of membranes. This is also reflected in a truncated apoptotic pathway, described in this issue of the Biochemical Journal in an article by Koppers et al., which leads to a so-called ‘silent response’ in the female tract, whereby unused sperm are removed without inflammatory consequences that might otherwise be detrimental to the new embryo. This new study shows that sperm have not simply jettisoned unwanted cellular components, but have evolved a very appropriate systems biology adapted to the specialist role they have to perform.
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Pandey, Aastha, Santosh Kumar Yadav, Rahul Vishvkarma, Bineta Singh, Jagdamba P. Maikhuri, Singh Rajender, and Gopal Gupta. "The dynamics of gene expression during and post meiosis sets the sperm agenda." Molecular Reproduction and Development 86, no. 12 (October 7, 2019): 1921–39. http://dx.doi.org/10.1002/mrd.23278.

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33

Niedermayer, Uwe, A. Adelmann, S. Bettoni, M. Calvi, M. Dehler, E. Ferrari, F. Frei, et al. "Challenges in simulating beam dynamics of dielectric laser acceleration." International Journal of Modern Physics A 34, no. 36 (November 26, 2019): 1942031. http://dx.doi.org/10.1142/s0217751x19420314.

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Dielectric Laser Acceleration (DLA) achieves the highest gradients among structure-based electron accelerators. The use of dielectrics increases the breakdown field limit, and thus the achievable gradient, by a factor of at least 10 in comparison to metals. Experimental demonstrations of DLA in 2013 led to the Accelerator on a Chip International Program (ACHIP), funded by the Gordon and Betty Moore Foundation. In ACHIP, our main goal is to build an accelerator on a silicon chip, which can accelerate electrons from below 100 keV to above 1 MeV with a gradient of at least 100 MeV/m. For stable acceleration on the chip, magnet-only focusing techniques are insufficient to compensate the strong acceleration defocusing. Thus, spatial harmonic and Alternating Phase Focusing (APF) laser-based focusing techniques have been developed. We have also developed the simplified symplectic tracking code DLAtrack6D, which makes use of the periodicity and applies only one kick per DLA cell, which is calculated by the Fourier coefficient of the synchronous spatial harmonic. Due to coupling, the Fourier coefficients of neighboring cells are not entirely independent and a field flatness optimization (similarly as in multi-cell cavities) needs to be performed. The simulation of the entire accelerator on a chip by a Particle In Cell (PIC) code is possible, but impractical for optimization purposes. Finally, we have also outlined the treatment of wake field effects in attosecond bunches in the grating within DLAtrack6D, where the wake function is computed by an external solver.
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34

Linck, R. W., M. J. Goggin, J. M. Norrander, and W. Steffen. "Characterization of antibodies as probes for structural and biochemical studies of tektins from ciliary and flagellar microtubules." Journal of Cell Science 88, no. 4 (November 1, 1987): 453–66. http://dx.doi.org/10.1242/jcs.88.4.453.

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Rabbit antibodies raised and purified against three tektins, proteins of flagellar doublet microtubules from sea-urchin sperm (Lytechinus pictus and Strongylocentrotus purpuratus), were used to study tektin biochemistry and their structural localization. Doublet microtubules were fractionated into tektin filaments and separated by SDS-PAGE into three major tektin polypeptide bands (Mr = 47, 51 and 55 (X 10(3)), which were used to immunize rabbits. Antibodies against each tektin (anti-tektins) were affinity-purified and then characterized by two-dimensional isoelectric focusing/SDS-PAGE immunoblotting and by immunofluorescence microscopy. In two-dimensional immunoblots of 0.5% Sarkosyl-resistant fractions of flagellar microtubules, the antibody against the 55 X 10(3) Mr tektin (anti-55) stained one major polypeptide of 55 X 10(3) Mr and pI 6.9, anti-51 stained two polypeptides of 51 X 10(3) Mr and pI approximately 6.15, and anti-47 stained one major polypeptide of 47 X 10(3) Mr and pI 6.15. The anti-tektins also stained several minor neighbouring polypeptides, which may be isoelectric variants, novel tektins or unrelated proteins. Furthermore, anti-47 crossreacted with the major 55 X 10(3) Mr polypeptide. By immunofluorescence microscopy all three anti-tektins stained methanol-fixed echinoderm sperm flagella and embryonic cilia. In addition, anti-47 and anti-55 stained unfixed, demembranated axonemes. Besides staining axonemes, all anti-tektins labelled the basal body region, and anti-51 labelled the sperm head envelope. These results indicate that the tektins are a complex family of proteins that are components of axonemal microtubules and possibly other cytoplasmic and nuclear structures.
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Lin, Yu-Hua, Chia-Yen Huang, Chih-Chun Ke, Ya-Yun Wang, Tsung-Hsuan Lai, Hsuan-Che Liu, Wei-Chi Ku, Chying-Chyuan Chan, and Ying-Hung Lin. "ACTN4 Mediates SEPT14 Mutation-Induced Sperm Head Defects." Biomedicines 8, no. 11 (November 19, 2020): 518. http://dx.doi.org/10.3390/biomedicines8110518.

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Septins (SEPTs) are highly conserved GTP-binding proteins and the fourth component of the cytoskeleton. Polymerized SEPTs participate in the modulation of various cellular processes, such as cytokinesis, cell polarity, and membrane dynamics, through their interactions with microtubules, actin, and other cellular components. The main objective of this study was to dissect the molecular pathological mechanism of SEPT14 mutation-induced sperm head defects. To identify SEPT14 interactors, co-immunoprecipitation (co-IP) and nano-liquid chromatography-mass spectrometry/mass spectrometry were applied. Immunostaining showed that SEPT14 was significantly localized to the manchette structure. The SEPT14 interactors were identified and classified as (1) SEPT-, (2) microtubule-, (3) actin-, and (4) sperm structure-related proteins. One interactor, ACTN4, an actin-holding protein, was selected for further study. Co-IP experiments showed that SEPT14 interacts with ACTN4 in a male germ cell line. SEPT14 also co-localized with ACTN4 in the perinuclear and manchette regions of the sperm head in early elongating spermatids. In the cell model, mutated SEPT14 disturbed the localization pattern of ACTN4. In a clinical aspect, sperm with mutant SEPT14, SEPT14A123T (p.Ala123Thr), and SEPT14I333T (p.Ile333Thr), have mislocalized and fragmented ACTN4 signals. Sperm head defects in donors with SEPT14 mutations are caused by disruption of the functions of ACTN4 and actin during sperm head formation.
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36

Matsumura, H., A. Takada, T. Namiki, and E. Nishimura. "567 Skin aging and carcinogenesis mechanisms by focusing on the stem cell competitive dynamics." Journal of Investigative Dermatology 142, no. 12 (December 2022): S278. http://dx.doi.org/10.1016/j.jid.2022.09.583.

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37

Mejía-Flores, Itzayana, Natalia Chiquete-Félix, Icela Palma-Lara, Salvador Uribe-Carvajal, and María de Lourdes Juárez-Mosqueda. "During capacitation in bull spermatozoa, actin and PLC-ζ undergo dynamic interactions." Zygote 25, no. 5 (September 20, 2017): 558–66. http://dx.doi.org/10.1017/s0967199417000260.

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SummaryThe migration pattern of sperm-specific phospholipase C-ζ (PLC-ζ) was followed and the role of this migration in actin cytoskeleton dynamics was determined. We investigated whether PLC-ζ exits sperm, opening the possibility that PLC-ζ is the ‘spermatozoidal activator factor’ (SOAF). As capacitation progresses, the highly dynamic actin cytoskeleton bound different proteins to regulate their location and activity. PLC-ζ participation at the start of fertilization was established. In non-capacitated spermatozoa, PLC-ζ is in the perinuclear theca (PT) and in the flagellum, therefore it was decided to determine whether bovine sperm actin interacts with PLC-ζ to direct its relocation as it progresses from non-capacitated (NC) to capacitated (C) and to acrosome-reacted (AR) spermatozoa. PLC-ζ interacted with actin in NC spermatozoa (100%), PLC-ζ levels decreased in C spermatozoa to 32% and in AR spermatozoa to 57% (P < 0.001). The level of actin/PLC-ζ interaction was twice as high in G-actin (P < 0.001) that reflected an increase in affinity. Upon reaching the AR spermatozoa, PLC-ζ was partially released from the cell. It was concluded that actin cytoskeleton dynamics control the migration of PLC-ζ during capacitation and leads to its partial release at AR spermatozoa. It is suggested that liberated PLC-ζ could reach the egg and favour fertilization.
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38

Chankitisakul, Vibuntita, Theerawat Tharasanit, Kriengsak Tasripoo, and Mongkol Techakumphu. "Chronological Reorganization of Microtubules, Actin Microfilaments, and Chromatin during the First Cell Cycle in Swamp Buffalo (Bubalus bubalis) Embryos." Veterinary Medicine International 2010 (2010): 1–8. http://dx.doi.org/10.4061/2010/382989.

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This paper aimed to study the dynamics of early embryonic development, in terms of redistribution of cytoskeleton (microtubules, actin microfilaments) and chromatin configurations during the first cell cycle in swamp buffalo embryos. Oocytes were matured and fertilizedin vitro, and they were fixed at various time points after IVF. At 6 h after IVF, 44.4% matured oocytes were penetrated by spermatozoa. Partial ZP digestion, however, did not improve fertilization rate compared to control (P>.05). At 12 h after IVF, the fertilized oocytes progressed to the second meiotic division and formed the female pronucleus simultaneously with the paternal chromatin continued to decondense. A sperm aster was observed radiating from the base of the decondensing sperm head. At 18 h after IVF, most presumptive zygotes had reached the pronuclear stage. The sperm aster was concurrently enlarged to assist the migration and apposition of pronuclei. Cell cleavage was facilitated by microfilaments and firstly observed by 30 h after IVF. In conclusion, the cytoskeleton actively involves with the process of fertilization and cleavage in swamp buffalo oocytes. The centrosomal material is paternally inherited. Fertilization failure is predominantly caused by poor sperm penetration. However, partial digestion of ZP did not improve fertilization rate.
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39

Fechter, J., A. Schöneberg, and G. Schatten. "Excision and disassembly of sperm tail microtubules during sea urchin fertilization: Requirements for microtubule dynamics." Cell Motility and the Cytoskeleton 35, no. 4 (1996): 281–88. http://dx.doi.org/10.1002/(sici)1097-0169(1996)35:4<281::aid-cm1>3.0.co;2-a.

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40

Bosakova, Tereza, Antonin Tockstein, Natasa Sebkova, Ondrej Simonik, Hana Adamusova, Jana Albrechtova, Tomas Albrecht, Zuzana Bosakova, and Katerina Dvorakova-Hortova. "New Insight into Sperm Capacitation: A Novel Mechanism of 17β-Estradiol Signalling." International Journal of Molecular Sciences 19, no. 12 (December 12, 2018): 4011. http://dx.doi.org/10.3390/ijms19124011.

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17β-estradiol (estradiol) is a natural estrogen regulating reproduction including sperm and egg development, sperm maturation—called capacitation—and sperm–egg communication. High doses can increase germ cell apoptosis and decrease sperm count. Our aim was to answer the biological relevance of estradiol in sperm capacitation and its effect on motility and acrosome reaction to quantify its interaction with estrogen receptors and propose a model of estradiol action during capacitation using kinetic analysis. Estradiol increased protein tyrosine phosphorylation, elevated rate of spontaneous acrosome reaction, and altered motility parameters measured Hamilton-Thorne Computer Assisted Semen Analyzer (CASA) in capacitating sperm. To monitor time and concentration dependent binding dynamics of extracellular estradiol, high-performance liquid chromatography with tandem mass spectrometry was used to measure sperm response and data was subjected to kinetic analysis. The kinetic model of estradiol action during sperm maturation shows that estradiol adsorption onto a plasma membrane surface is controlled by Langmuir isotherm. After, when estradiol passes into the cytoplasm, it forms an unstable adduct with cytoplasmic receptors, which display a signalling autocatalytic pattern. This autocatalytic reaction suggests crosstalk between receptor and non-receptor pathways utilized by sperm prior to fertilization.
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41

Wewala, W. A. H. S. S., Jafar Khan Kasi, Ajab Khan Kasi, and Nitin Afzulpurkar. "Cell Separation Through Ascending and Descending Curvilinear Microchannels." Applied Mechanics and Materials 300-301 (February 2013): 1649–53. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.1649.

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Separation of rare cells such as fetal cells from blood has potential importance in disease investigation and prevention. In this paper we report a new method of cancer cells separation from patient’s blood by inertial focusing technique. A design and simulation of ascending and descending curvilinear microchannels for separation of particles resembling cancer cells have been presented. Computational fluid dynamics (CFD) design and simulation of ascending and descending microchannels is used for cell separation. The simulation was carried out in two stages including focusing and separation. The ascending curvilinear channel design demonstrated favorable focusing and separation. Separation with 100% purity and efficiency of the unwanted particle was achieved at Reynolds number (Re) = 8.50 and velocity 0.105m/s. Reynolds number 9.25 and 10.06 with corresponding velocities 0.115 m/s and 0.125 m/s were also investigated for cell seperation. In case of descending curvilinear channel, cell separation was not good. Considering cancer cells size about 15 µm, our proposed ascending microchannel is a good candidate for cancer cells separation from blood.
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42

Nichols, Zoe G., Vahid Zadmajid, Vaishnavi Dalal, Jim Stoeckel, William Wayman, and Ian A. E. Butts. "Reproductive aspects of freshwater unionid mussel sperm: Seasonal dynamics, male-to male variability, and cell quantification." Animal Reproduction Science 230 (July 2021): 106768. http://dx.doi.org/10.1016/j.anireprosci.2021.106768.

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43

Hamamura, Yuki, Chieko Saito, Chie Awai, Daisuke Kurihara, Atsushi Miyawaki, Tsuyoshi Nakagawa, Masahiro M. Kanaoka, et al. "Live-Cell Imaging Reveals the Dynamics of Two Sperm Cells during Double Fertilization in Arabidopsis thaliana." Current Biology 21, no. 6 (March 2011): 497–502. http://dx.doi.org/10.1016/j.cub.2011.02.013.

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44

Purohit, Ashok, Vijay B. Joshi, and Keshav Vyas. "Effect of Various Chromatographic Fractions of Neem Seed Oil on Sperm Dynamics and Testicular Cell Population Dynamics of Male Albino Rats." Pharmaceutical Biology 46, no. 9 (January 2008): 660–64. http://dx.doi.org/10.1080/13880200802215263.

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45

Félix, Francisca, Catarina C. V. Oliveira, and Elsa Cabrita. "Antioxidants in Fish Sperm and the Potential Role of Melatonin." Antioxidants 10, no. 1 (December 31, 2020): 36. http://dx.doi.org/10.3390/antiox10010036.

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In recent years, the effects of novel antioxidants have played an important role in the research focusing on fish cell protection. As food demand grows, aquaculture production becomes more intensive, and fish are more exposed to oxidative stress conditions, like high densities, temperature shifting, frequent fish handling and samplings, and prophylactic or disease treatments, which expose fish to a different environment. Particularly in reproduction, germ cells lose antioxidant capacity with spermatogenesis, as spermatozoa are more prone to oxidative stress. Antioxidants have been used in a variety of fish physiological problems including in reproduction and in the establishment of cryopreservation protocols. From the most used antioxidants to natural plant food and herbs, and endogenously produced antioxidants, like melatonin, a review of the literature available in terms of their effects on the protection of fish spermatozoa is presented here in a classified structure. Several direct and indirect approaches to improve gamete quality using antioxidants administration are mentioned (through feed supplementation or by adding in cryopreservation media), as well as factors affecting the efficiency of these molecules and their mechanisms of action. Special attention is given to the unclear melatonin pathway and its potential scavenger activity to prevent and counteract oxidative stress damage on fish spermatozoa.
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46

Miller, Kelly E., and Rebecca Heald. "Glutamylation of Nap1 modulates histone H1 dynamics and chromosome condensation in Xenopus." Journal of Cell Biology 209, no. 2 (April 20, 2015): 211–20. http://dx.doi.org/10.1083/jcb.201412097.

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Linker histone H1 is required for mitotic chromosome architecture in Xenopus laevis egg extracts and, unlike core histones, exhibits rapid turnover on chromatin. Mechanisms regulating the recruitment, deposition, and dynamics of linker histones in mitosis are largely unknown. We found that the cytoplasmic histone chaperone nucleosome assembly protein 1 (Nap1) associates with the embryonic isoform of linker histone H1 (H1M) in egg extracts. Immunodepletion of Nap1 decreased H1M binding to mitotic chromosomes by nearly 50%, reduced H1M dynamics as measured by fluorescence recovery after photobleaching and caused chromosome decondensation similar to the effects of H1M depletion. Defects in H1M dynamics and chromosome condensation were rescued by adding back wild-type Nap1 but not a mutant lacking sites subject to posttranslational modification by glutamylation. Nap1 glutamylation increased the deposition of H1M on sperm nuclei and chromatin-coated beads, indicating that charge-shifting posttranslational modification of Nap1 contributes to H1M dynamics that are essential for higher order chromosome architecture.
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47

Burlibaşa, Liliana, and Lucian Gavrilă. "Molecular and ultrastructural studies of the sperm chromatin from Triturus cristatus." Zygote 13, no. 3 (August 2005): 197–205. http://dx.doi.org/10.1017/s0967199405003230.

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The study of nuclear molecular architecture during gametogenesis represents one approach towards the deciphering of the molecular organization of eukaryotic chromatin. During spermatogenesis, chromatin undergoes several dynamic transitions, which are often associated with important changes not only in its physical conformation but even in its composition and structure. Dynamic alterations in chromatin structure mediated by postsynthetic histone modification and DNA methylation constitute a major regulatory mechanism of gene function of eukaryotes. Using transmission electron microscopy and molecular investigations, some peculiar aspects of chromatin organization and evolution in spermatogenesis of the crested newt Triturus cristatus were investigated. We focused our investigations on the dynamics of chromatin structure after treatment with TSA (a histone deacetylase inhibitor).
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48

Zong, Hailing, Stephanie K. Carnes, Christina Moe, Claire E. Walczak, and Stephanie C. Ems-McClung. "The far C-terminus of MCAK regulates its conformation and spindle pole focusing." Molecular Biology of the Cell 27, no. 9 (May 2016): 1451–64. http://dx.doi.org/10.1091/mbc.e15-10-0699.

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To ensure proper spindle assembly, microtubule (MT) dynamics needs to be spatially regulated within the cell. The kinesin-13 MCAK is a potent MT depolymerase with a complex subcellular localization, yet how MCAK spatial regulation contributes to spindle assembly is not understood. Here we show that the far C-terminus of MCAK plays a critical role in regulating MCAK conformation, subspindle localization, and spindle assembly in Xenopus egg extracts. Alteration of MCAK conformation by the point mutation E715A/E716A in the far C-terminus increased MCAK targeting to the poles and reduced MT lifetimes, which induced spindles with unfocused poles. These effects were phenocopied by the Aurora A phosphomimetic mutation, S719E. Furthermore, addition of the kinesin-14 XCTK2 to spindle assembly reactions rescued the unfocused-pole phenotype. Collectively our work shows how the regional targeting of MCAK regulates MT dynamics, highlighting the idea that multiple phosphorylation pathways of MCAK cooperate to spatially control MT dynamics to maintain spindle architecture.
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49

Van Blerkom, Jonathan, Patrick Davis, John Merriam, and Jane Sinclair. "Nuclear and cytoplasmic dynamics of sperm penetration, pronuclear formation and microtubule organization during fertilization and early preimplantation development in the human." Human Reproduction Update 1, no. 5 (January 1, 1995): 429–61. http://dx.doi.org/10.1093/humupd/1.5.429.

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Abstract This report describes spatial and temporal aspects of sperm penetration and intracytoplasmic migration, pronuclear evolution and the specificity of presyngamic opposition, stage-specific changes in cytoskeletal organization and the relative contribution of maternal and paternal components to mitotic spindle formation. These studies involved observations of living human oocytes during conventional insemination in vitro and after intracytoplasmic deposition of spermatozoa, analysis of chromatin organization and distribution during pronuclear evolution, and detection of actin and α-, rβ- and γ-tubulin by confocal immuno-fluorescence microscopy. Immature and mature oocytes, penetrated but unfertilized oocytes, fertilized but arrested eggs, and cleavage-stage embryos from normal and dispermic fertilizations were examined. The results demonstrate that sperm nuclear migration to the maternal perinuclear region is rapid and linear, occurs in the absence of a detectable cytoskeletal system and appears to be assisted by an unusual configuration of the sperm tail principal piece which results from either retained intracytoplasmic motility or the process by which the sperm tail is progressively incorporated into the oocyte. Our findings also show a specificity of pronuclear alignment that is associated with a polarized distribution of both maternal and paternal chromatin, and with the position of the sperm centrosome and the presence of microtubules nucleated from this structure. The results also indicate that a maternal microtubule nucleating capacity is present in the immature oocyte but is apparently inactive until spindle formation. The poles of the first mitotic spindle appear to be derived from the sperm centrosome, although some maternal contribution cannot be excluded. The sperm tail and centrosome persist in a single cell through the cleavage stages, and the latter serves as a prominent site of cytoplasmic microtubule nucleation. The results provide a detailed understanding of the cellular and nuclear morphodynamics of the human fertilization process and indicate subtle defects that may be responsible for early developmental failure.
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Lloyd, R. E., E. Badia, A. Fazeli, P. F. Watson, and W. V. Holt. "Temporal dynamics of ram sperm binding and survival during 48-h coculture with oviducal epithelial cells." Reproduction, Fertility and Development 20, no. 7 (2008): 835. http://dx.doi.org/10.1071/rd08027.

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Following insemination, ram spermatozoa bind to oviducal epithelial cells (OEC) in vivo and remain viable for several hours before fertilisation. In the present study, we investigated whether OEC monolayers reproduce this effect in vitro, performing an analysis of ram sperm binding and survival over an extended (48 h) period at 39°C. We wanted to determine whether the reproductive cycle phase and/or oviducal region would influence ram sperm binding and survival in coculture with OEC and whether reproductive and non-reproductive epithelial cells bound and maintained the viability of ram spermatozoa equivalently. Oviducts were separated into groups based on their ovarian state (follicular or luteal) and then divided into two parts (isthmus and ampulla) for OEC isolation. Sheep kidney epithelial cells (Madin-Darby ovine kidney; MDOK) were purchased commercially. Reproductive cycle phase, but not oviducal region, affected sperm binding to OEC. Although more spermatozoa bound to luteal OEC than to follicular OEC at 1 h, at 24 h follicular OEC had bound more spermatozoa than luteal OEC. Generally, spermatozoa that were bound to OEC and MDOK had enhanced viability at each of the time points investigated (1, 6, 24 and 48 h), but the viability of the OEC-bound spermatozoa was greater than that of the MDOK-bound spermatozoa at 48 h. In conclusion, ram sperm–epithelial cell interactions are temporal, dynamic and depend on the origin of the epithelial cells.
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