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Advanced Science (Weinheim,... Oct 2021Microscale self-propelled robots show great promise in the biomedical field and are the focus of many researchers. These tiny devices, which move and navigate by...
Microscale self-propelled robots show great promise in the biomedical field and are the focus of many researchers. These tiny devices, which move and navigate by themselves, are typically based on inorganic microstructures that are not biodegradable and potentially toxic, often using toxic fuels or elaborate external energy sources, which limits their real-world applications. One potential solution to these issues is to go back to nature. Here, the authors use high-speed Aqua Sperm micromotors obtained from North African catfish (Clarias gariepinus, B. 1822) to destroy bacterial biofilm. These Aqua Sperm micromotors use water-induced dynein ATPase catalyzed adenosine triphosphate (ATP) degradation as biocompatible fuel to trigger their fast speed and snake-like undulatory locomotion that facilitate biofilm destruction in less than one minute. This efficient biofilm destruction is due to the ultra-fast velocity as well as the head size of Aqua Sperm micromotors being similar to bacteria, which facilitates their entry to and navigation within the biofilm matrix. In addition, the authors demonstrate the real-world application of Aqua Sperm micromotors by destroying biofilms that had colonized medical and laboratory tubing. The implemented system extends the biomedical application of Aqua Sperm micromotors to include hybrid robots for fertilization or cargo tasks.
Topics: Animals; Biofilms; Biomimetics; Catfishes; Equipment Contamination; Equipment Design; Male; Microtechnology; Robotics; Spermatocytes
PubMed: 34369099
DOI: 10.1002/advs.202101301 -
Systems Biology in Reproductive Medicine Aug 2018Per- and polyfluoroalkyl substances (PFASs) represent a highly ubiquitous group of synthetic chemicals used in products ranging from water and oil repellents and...
UNLABELLED
Per- and polyfluoroalkyl substances (PFASs) represent a highly ubiquitous group of synthetic chemicals used in products ranging from water and oil repellents and lubricants to firefighting foam. These substances can enter and accumulate in multiple tissue matrices in up to 100% of people assessed. Though animal models strongly identify these compounds as male reproductive toxicants, with exposed rodents experiencing declines in sperm count, alterations in hormones, and DNA damage in spermatids, among other adverse outcomes, human studies report conflicting conclusions as to the reproductive toxicity of these chemicals. Using an innovative, human stem-cell-based model of spermatogenesis, we assessed the effects of the PFASs perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and a mixture of PFOS, PFOA, and PFNA for their impacts on human spermatogenesis in vitro under conditions relevant to the general and occupationally exposed populations. Here, we show that PFOS, PFOA, PFNA, and a mixture of PFOS, PFOA, and PFNA do not decrease in vitro germ cell viability, consistent with reports from human studies. These compounds do not affect mitochondrial membrane potential or increase reactive oxygen species generation, and they do not decrease cell viability of spermatogonia, primary spermatocytes, secondary spermatocytes, or spermatids in vitro under the conditions examined. However, exposure to PFOS, PFOA, and PFNA reduces expression of markers for spermatogonia and primary spermatocytes. While not having direct effects on germ cell viability, these effects suggest the potential for long-term impacts on male fertility through the exhaustion of the spermatogonial stem cell pool and abnormalities in primary spermatocytes.
ABBREVIATIONS
CDC: Centers for Disease Control; DMSO: dimethyl sulfoxide; GHR: growth hormone receptor; hESCs: human embryonic stem cells; PFASs: per- and polyfluoroalkyl substances; PFCs: perfluorinated compounds; PFNA: perfluorononanoic acid; PFOS: perfluorooctanesulfonic acid; PFOA: perfluorooctanoic acid; PLZF: promyelocytic leukemia zinc finger; ROS: reactive oxygen species; HILI: RNA-mediated gene silencing 2; SSC: spermatogonial stem cell.
Topics: Alkanesulfonic Acids; Argonaute Proteins; Caprylates; Cell Survival; Cells, Cultured; Embryonic Stem Cells; Fatty Acids; Fluorocarbons; Humans; Male; Mitochondria; Promyelocytic Leukemia Zinc Finger Protein; Reactive Oxygen Species; Spermatocytes; Spermatogenesis; Spermatogonia
PubMed: 29911897
DOI: 10.1080/19396368.2018.1481465 -
The Journal of Cell Biology Oct 2009Meiosis-specific mammalian cohesin SMC1beta is required for complete sister chromatid cohesion and proper axes/loop structure of axial elements (AEs) and synaptonemal...
Meiosis-specific mammalian cohesin SMC1beta is required for complete sister chromatid cohesion and proper axes/loop structure of axial elements (AEs) and synaptonemal complexes (SCs). During prophase I, telomeres attach to the nuclear envelope (NE), but in Smc1beta(-/-) meiocytes, one fifth of their telomeres fail to attach. This study reveals that SMC1beta serves a specific role at telomeres, which is independent of its role in determining AE/SC length and loop extension. SMC1beta is necessary to prevent telomere shortening, and SMC3, present in all known cohesin complexes, properly localizes to telomeres only if SMC1beta is present. Very prominently, telomeres in Smc1beta(-/-) spermatocytes and oocytes loose their structural integrity and suffer a range of abnormalities. These include disconnection from SCs and formation of large telomeric protein-DNA extensions, extended telomere bridges between SCs, ring-like chromosomes, intrachromosomal telomeric repeats, and a reduction of SUN1 foci in the NE. We suggest that a telomere structure protected from DNA rearrangements depends on SMC1beta.
Topics: Animals; Cell Cycle Proteins; Chromosomal Proteins, Non-Histone; Female; Male; Meiosis; Mice; Mice, Knockout; Microscopy, Electron; Oocytes; Spermatocytes; Telomere; Cohesins
PubMed: 19841137
DOI: 10.1083/jcb.200808016 -
Cell Cycle (Georgetown, Tex.) Nov 2008The specialized cell cycles that characterize various aspects of the differentiation of germ cells provide a unique opportunity to understand heretofore elusive aspects... (Review)
Review
The specialized cell cycles that characterize various aspects of the differentiation of germ cells provide a unique opportunity to understand heretofore elusive aspects of the in vivo function of cell cycle regulators. Key components of the cell cycle machinery are the regulatory sub-units, the cyclins, and their catalytic partners, the cyclin-dependent kinases. Some of the cyclins exhibit unique patterns of expression in germ cells that suggest possible concomitant distinct functions, predictions that are being explored by targeted mutagenesis in mouse models. A novel, meiosis-specific function has been shown for one of the A-type cyclins, cyclin A1. Embryonic lethality has obviated understanding of the germline functions of cyclin A2 and cyclin B1, while yet other cyclins, although expressed at specific stages of germ cell development, may have less essential function in the male germline.
Topics: Animals; Cell Cycle; Cyclin-Dependent Kinase 2; Cyclins; Humans; Male; Meiosis; Mice; Mitosis; Spermatocytes
PubMed: 19001847
DOI: 10.4161/cc.7.22.6978 -
Reproductive Biology and Endocrinology... Jul 2008Spermatogenesis and fertilization are highly unique processes. Discovery and characterization of germ cell-specific genes are important for the understanding of these...
BACKGROUND
Spermatogenesis and fertilization are highly unique processes. Discovery and characterization of germ cell-specific genes are important for the understanding of these reproductive processes. We investigated eight proteins encoded by novel spermatogenic cell-specific genes previously identified from the mouse round spermatid UniGene library.
METHODS
Polyclonal antibodies were generated against the novel proteins and western blot analysis was performed with various protein samples. Germ cell specificity was investigated using testes from germ cell-less mutant mice. Developmental expression pattern was examined in testicular germ cells, testicular sperm and mature sperm. Subcellular localization was assessed by cell surface biotin labeling and trypsinization. Protein localization and properties in sperm were investigated by separation of head and tail fractions, and extractabilities by a non-ionic detergent and urea.
RESULTS
The authenticity of the eight novel proteins and their specificity to spermatogenic cells were confirmed. In examining the developmental expression patterns, we found the presence of four proteins only in testicular germ cells, a single protein in testicular germ cells and testicular sperm, and three proteins in the testicular stages and mature sperm from the epididymis. Further analysis of the three proteins present in sperm disclosed that one is located at the surface of the acrosomal region and the other two are associated with cytoskeletal structures in the sperm flagellum. We name the genes for these sperm proteins Shsp1 (Sperm head surface protein 1), Sfap1 (Sperm flagellum associated protein 1) and Sfap2 (Sperm flagellum associated protein 2).
CONCLUSION
We analyzed eight novel germ cell-specific proteins, providing new and inclusive information about their developmental and cellular characteristics. Our findings will facilitate future investigation into the biological roles of these novel proteins in spermatogenesis and sperm functions.
Topics: Acrosome; Animals; Antibodies; Antibody Specificity; Blotting, Western; Gene Expression Profiling; Gene Expression Regulation; Gene Library; Male; Meiosis; Mice; Mitosis; Proteins; Sperm Tail; Spermatids; Spermatocytes; Spermatogenesis
PubMed: 18652659
DOI: 10.1186/1477-7827-6-32 -
Journal of Visualized Experiments : JoVE Nov 2017Mammalian meiosis is a dynamic developmental process that occurs in germ cells and can be studied and characterized. Using a method to spread nuclei on the surface of...
Mammalian meiosis is a dynamic developmental process that occurs in germ cells and can be studied and characterized. Using a method to spread nuclei on the surface of slides (rather than dropping them from a height), we demonstrate an optimized technique on mouse spermatocytes that was first described in 1997. This method is widely used in laboratories to study mammalian meiosis because it yields a plethora of high quality nuclei undergoing substages of prophase I. Seminiferous tubules are first placed in a hypotonic solution to swell spermatocytes. Then spermatocytes are released into a sucrose solution to create a cell suspension, and nuclei are spread onto fixative-soaked glass slides. Following immunostaining, a diversity of proteins germane to meiotic processes can be examined. For example, proteins of the synaptonemal complex, a tripartite structure that connects the chromosome axes/cores of homologs together can be easily visualized. Meiotic recombination proteins, which are involved in repair of DNA double-strand breaks by homologous recombination, can also be immunostained to evaluate progression of prophase I. Here we describe and demonstrate in detail a technique widely used to study mammalian meiosis in spermatocytes from juvenile or adult male mice.
Topics: Animals; Chromosomes; Male; Meiosis; Mice; Spermatocytes
PubMed: 29286440
DOI: 10.3791/55378 -
PLoS Genetics Mar 2019Spermatogenesis is the process by which male gametes are formed from a self-renewing population of spermatogonial stem cells (SSCs) residing in the testis. SSCs...
Spermatogenesis is the process by which male gametes are formed from a self-renewing population of spermatogonial stem cells (SSCs) residing in the testis. SSCs represent less than 1% of the total testicular cell population in adults, but must achieve a stable balance between self-renewal and differentiation. Once differentiation has occurred, the newly formed and highly proliferative spermatogonia must then enter the meiotic program in which DNA content is doubled, then halved twice to create haploid gametes. While much is known about the critical cellular processes that take place during the specialized cell division that is meiosis, much less is known about how the spermatocytes in the "first-wave" in juveniles compare to those that contribute to long-term, "steady-state" spermatogenesis in adults. Given the strictly-defined developmental process of spermatogenesis, this study explored the transcriptional profiles of developmental cell stages during testis maturation. Using a combination of comprehensive germ cell sampling with high-resolution, single-cell-mRNA-sequencing, we have generated a reference dataset of germ cell gene expression. We show that discrete developmental stages of spermatogenesis possess significant differences in the transcriptional profiles from neonates compared to juveniles and adults. Importantly, these gene expression dynamics are also reflected at the protein level in their respective cell types. We also show differential utilization of many biological pathways with age in both spermatogonia and spermatocytes, demonstrating significantly different underlying gene regulatory programs in these cell types over the course of testis development and spermatogenic waves. This dataset represents the first unbiased sampling of spermatogonia and spermatocytes during testis maturation, at high-resolution, single-cell depth. Not only does this analysis reveal previously unknown transcriptional dynamics of a highly transitional cell population, it has also begun to reveal critical differences in biological pathway utilization in developing spermatogonia and spermatocytes, including response to DNA damage and double-strand breaks.
Topics: Adult Germline Stem Cells; Animals; Animals, Newborn; Cell Differentiation; Gene Expression Profiling; Male; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Sex Differentiation; Single-Cell Analysis; Spermatocytes; Spermatogenesis; Spermatogonia; Testis; Transcriptome
PubMed: 30893341
DOI: 10.1371/journal.pgen.1007810 -
Endocrinology Jun 2010Sertoli cell tight junctions (TJs) are an essential component of the blood-testis barrier required for spermatogenesis; however, the role of gonadotropins in their...
Sertoli cell tight junctions (TJs) are an essential component of the blood-testis barrier required for spermatogenesis; however, the role of gonadotropins in their maintenance is unknown. This study aimed to investigate the effect of gonadotropin suppression and short-term replacement on TJ function and TJ protein (occludin and claudin-11) expression and localization, in an adult rat model in vivo. Rats (n = 10/group) received the GnRH antagonist, acyline, for 7 wk to suppress gonadotropins. Three groups then received for 7 d: 1) human recombinant FSH, 2) human chorionic gonadotropin (hCG) and rat FSH antibody (to study testicular androgen stimulation alone), and 3) hCG alone (to study testicular androgen and pituitary FSH production). TJ proteins were assessed by real-time PCR, Western blot analysis, and immunohistochemistry, whereas TJ function was assessed with a biotin permeation tracer. Acyline treatment significantly reduced testis weights, serum androgens, LH and FSH, and adluminal germ cells (pachytene spermatocyte, round and elongating spermatids). In contrast to controls, acyline induced seminiferous tubule permeability to biotin, loss of tubule lumens, and loss of occludin, but redistribution of claudin-11, immunostaining. Short-term hormone replacement stimulated significant recoveries in adluminal germ cell numbers. In hCG +/- FSH antibody-treated rats, occludin and claudin-11 protein relocalized at the TJ, but such relocalization was minimal with FSH alone. Tubule lumens also reappeared, but most tubules remained permeable to biotin tracer, despite the presence of occludin. It is concluded that gonadotropins maintain Sertoli cell TJs in the adult rat via a mechanism that includes the localization of occludin and claudin-11 at functional TJs.
Topics: Androgens; Animals; Blotting, Western; Chorionic Gonadotropin; Claudins; Follicle Stimulating Hormone; Gonadotropin-Releasing Hormone; Gonadotropins; Immunohistochemistry; Luteinizing Hormone; Male; Membrane Proteins; Nerve Tissue Proteins; Occludin; Oligopeptides; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Spermatids; Spermatocytes; Spermatogonia; Testis; Tight Junctions
PubMed: 20357222
DOI: 10.1210/en.2009-1278 -
Nucleic Acids Research May 2020Previously, we have shown that human sperm Prohibitin (PHB) expression is significantly negatively correlated with mitochondrial ROS levels but positively correlated...
Previously, we have shown that human sperm Prohibitin (PHB) expression is significantly negatively correlated with mitochondrial ROS levels but positively correlated with mitochondrial membrane potential and motility. However, the possible role of PHB in mammalian spermatogenesis has not been investigated. Here we document the presence of PHB in spermatocytes and its functional roles in meiosis by generating the first male germ cell-specific Phb-cKO mouse. Loss of PHB in spermatocytes resulted in complete male infertility, associated with not only meiotic pachytene arrest with accompanying apoptosis, but also apoptosis resulting from mitochondrial morphology and function impairment. Our mechanistic studies show that PHB in spermatocytes regulates the expression of STAG3, a key component of the meiotic cohesin complex, via a non-canonical JAK/STAT pathway, and consequently promotes meiotic DSB repair and homologous recombination. Furthermore, the PHB/JAK2 axis was found as a novel mechanism in the maintenance of stabilization of meiotic STAG3 cohesin complex and the modulation of heterochromatin formation in spermatocytes during meiosis. The observed JAK2-mediated epigenetic changes in histone modifications, reflected in a reduction of histone 3 tyrosine 41 phosphorylation (H3Y41ph) and a retention of H3K9me3 at the Stag3 locus, could be responsible for Stag3 dysregulation in spermatocytes with the loss of PHB.
Topics: Animals; Cell Cycle Proteins; Cell Line; Chromosome Pairing; Epigenome; Histone Code; Histones; Homologous Recombination; Infertility; Janus Kinase 2; Janus Kinases; Male; Meiosis; Mice; Mice, Knockout; Mitochondria; Pachytene Stage; Phosphorylation; Prohibitins; Repressor Proteins; STAT Transcription Factors; Signal Transduction; Spermatocytes; Spermatogenesis; Testis
PubMed: 32232334
DOI: 10.1093/nar/gkaa203 -
Genes & Development May 2020Cell type-specific transcriptional programs that drive differentiation of specialized cell types are key players in development and tissue regeneration. One of the most...
Cell type-specific transcriptional programs that drive differentiation of specialized cell types are key players in development and tissue regeneration. One of the most dramatic changes in the transcription program in occurs with the transition from proliferating spermatogonia to differentiating spermatocytes, with >3000 genes either newly expressed or expressed from new alternative promoters in spermatocytes. Here we show that opening of these promoters from their closed state in precursor cells requires function of the spermatocyte-specific tMAC complex, localized at the promoters. The spermatocyte-specific promoters lack the previously identified canonical core promoter elements except for the Inr. Instead, these promoters are enriched for the binding site for the TALE-class homeodomain transcription factors Achi/Vis and for a motif originally identified under tMAC ChIP-seq peaks. The tMAC motif resembles part of the previously identified 14-bp β2UE1 element critical for spermatocyte-specific expression. Analysis of downstream sequences relative to transcription start site usage suggested that ACA and CNAAATT motifs at specific positions can help promote efficient transcription initiation. Our results reveal how promoter-proximal sequence elements that recruit and are acted upon by cell type-specific chromatin binding complexes help establish a robust, cell type-specific transcription program for terminal differentiation.
Topics: Amino Acid Motifs; Animals; Base Sequence; Drosophila Proteins; Drosophila melanogaster; Male; Promoter Regions, Genetic; Spermatocytes; Spermatogenesis; Transcription Initiation Site; Transcriptome
PubMed: 32217666
DOI: 10.1101/gad.335331.119