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1
Cordero, P., M. De los Reyes, V. H. Parraguez, M. Varas-Godoy, C. Torres, and O. Peralta. "206 Overexpression of germ cell genes DAZL, STRA8, and BOULE in bovine adipose tissue-derived mesenchymal stem cells for male germ cell derivation." Reproduction, Fertility and Development 32, no. 2 (2020): 231. http://dx.doi.org/10.1071/rdv32n2ab206.
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Invitro gamete derivation from stem cells has potential applications as an alternative method for dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSC) may be suitable candidates for invitro gamete derivation given their differentiation capacity and their potential for cell therapy. DAZL (deleted in azoospermia-like) and BOULE (also called BOLL) encode RNA-binding proteins that control differentiation of germ cells; STRA8 (stimulated by RA-8) encodes a protein required for meiosis. Considering the crucial roles of these factors, the aim of the present study was to evaluate co-overexpression of different combinations of DAZL, STRA8, and BOULE on germ cell gene expression profile in adipose tissue-derived MSC (AT-MSC). AT-MSC were harvested from abattoir-derived male bovine fetuses (n=9; 7-8 months of gestation). The optimal concentration of Lipofectamine 2000 (1, 1.5, 2, 1.5ng µL−1; Invitrogen) was analysed in AT-MSC transfected with plasmid pSIN-EF2-Puro containing DAZL, STRA8, and BOULE coding sequences (pSIN-EF2-DAZL-P2A-STRA8-T2A-BOULE-Puro). Then, AT-MSC were transfected either with plasmids containing DAZL, STRA8, and BOULE genes (pSIN-EF2-DAZL-P2A-STRA8-T2A-BOULE-Puro), DAZL and BOULE genes (pSIN-EF2-DAZL-P2A-STRA8-T2A-Puro), DAZL (pSIN-EF2-DAZL-P2A-T2A-Puro), or empty plasmid at a concentration of 1ng µL−1 of Lipofectamine. Cell samples were obtained from each plasmid treatment and analysed for expression of housekeeping genes ACTB and GAPDH and germ cell genes DAZL, PIWIl2, STRA8, and BOULE by quantitative-PCR using relative values (Quantity) through the ΔΔCT formula. AT-MSC transfected with pSIN-EF2-DAZL-P2A-STRA8-T2A-BOULE-Puro using 1ng µL−1 of Lipofectamine achieved higher (P<0.05) expression of DAZL (13.3-fold) compared with cells transfected with empty vector. Moreover, AT-MSC transfected with pSIN-EF2-DAZL-P2A-STRA8-T2A-BOULE-Puro had higher (P<0.05) levels of DAZL mRNA (3.8-fold) compared with empty vector. Messenger RNA levels of STRA8 (1.4-fold) were only detected in AT-MSC transfected with pSIN-EF2-DAZL-P2A-STRA8-T2A-Puro; PIWIl2 and BOULE were not detected in transfected or untransfected AT-MSC. In conclusion, bovine fetal AT-MSC are amenable for overexpression of germ cell markers DAZL and STRA8. Transfection with plasmid containing three germ cell genes (DAZL, STRA8, and BOULE) allowed overexpression of DAZL, whereas transfection with plasmid containing two germ cell genes (DAZL and STRA8) achieved overexpression of STRA8. This study was supported by Fondecyt grant 1191114, Government of Chile.
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Iyer, Harini, Melanie Issigonis, Prashant P. Sharma, Cassandra G. Extavour, and Phillip A. Newmark. "A premeiotic function for boule in the planarian Schmidtea mediterranea." Proceedings of the National Academy of Sciences 113, no. 25 (June 2, 2016): E3509—E3518. http://dx.doi.org/10.1073/pnas.1521341113.
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Mutations in Deleted in Azoospermia (DAZ), a Y chromosome gene, are an important cause of human male infertility. DAZ is found exclusively in primates, limiting functional studies of this gene to its homologs: boule, required for meiotic progression of germ cells in invertebrate model systems, and Daz-like (Dazl), required for early germ cell maintenance in vertebrates. Dazl is believed to have acquired its premeiotic role in a vertebrate ancestor following the duplication and functional divergence of the single-copy gene boule. However, multiple homologs of boule have been identified in some invertebrates, raising the possibility that some of these genes may play other roles, including a premeiotic function. Here we identify two boule paralogs in the freshwater planarian Schmidtea mediterranea. Smed-boule1 is necessary for meiotic progression of male germ cells, similar to the known function of boule in invertebrates. By contrast, Smed-boule2 is required for the maintenance of early male germ cells, similar to vertebrate Dazl. To examine if Boule2 may be functionally similar to vertebrate Dazl, we identify and functionally characterize planarian homologs of human DAZL/DAZ-interacting partners and DAZ family mRNA targets. Finally, our phylogenetic analyses indicate that premeiotic functions of planarian boule2 and vertebrate Dazl evolved independently. Our study uncovers a premeiotic role for an invertebrate boule homolog and offers a tractable invertebrate model system for studying the premeiotic functions of the DAZ protein family.
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Houston, D. W., J. Zhang, J. Z. Maines, S. A. Wasserman, and M. L. King. "A Xenopus DAZ-like gene encodes an RNA component of germ plasm and is a functional homologue of Drosophila boule." Development 125, no. 2 (January 15, 1998): 171–80. http://dx.doi.org/10.1242/dev.125.2.171.
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We have identified a localized RNA component of Xenopus germ plasm. This RNA, Xdazl (Xenopus DAZ-like), encodes a protein homologous to human DAZ (Deleted in Azoospermia), vertebrate DAZL and Drosophila Boule proteins. Human males deficient in DAZ have few or no sperm and boule mutant flies exhibit complete azoospermia and male sterility. Xdazl RNA was detected in the mitochondrial cloud and vegetal cortex of oocytes. In early embryos, the RNA was localized exclusively in the germ plasm. Consistent with other organisms, Xdazl RNA was also expressed in the spermatogonia and spermatocytes of frog testis. Proteins in the DAZ-family contain a conserved RNP domain implying an RNA-binding function. We have shown that Xdazl can function in vitro as an RNA-binding protein. To determine if the function of Xdazl in spermatogenesis was conserved, we introduced the Xdazl cDNA into boule flies. This resulted in rescue of the boule meiotic entry phenotype, including formation of spindles, phosphorylation of histone H3 and completion of meiotic cell division. Overall, these results suggest that Xdazl may be important for primordial germ cell specification in the early embryo and may play a role analogous to Boule in promoting meiotic cell division.
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Houston, D. W., and M. L. King. "A critical role for Xdazl, a germ plasm-localized RNA, in the differentiation of primordial germ cells in Xenopus." Development 127, no. 3 (February 1, 2000): 447–56. http://dx.doi.org/10.1242/dev.127.3.447.
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Xdazl is an RNA component of Xenopus germ plasm and encodes an RNA-binding protein that can act as a functional homologue of Drosophila boule. boule is required for entry into meiotic cell division during fly spermatogenesis. Both Xdazl and boule are related to the human DAZ and DAZL, and murine Dazl genes, which are also involved in gamete differentiation. As suggested from its germ plasm localization, we show here that Xdazl is critically involved in PGC development in Xenopus. Xdazl protein is expressed in the cytoplasm, specifically in the germ plasm, from blastula to early tailbud stages. Specific depletion of maternal Xdazl RNA results in tadpoles lacking, or severely deficient in, primordial germ cells (PGCs). In the absence of Xdazl, PGCs do not successfully migrate from the ventral to the dorsal endoderm and do not reach the dorsal mesentery. Germ plasm aggregation and intracellular movements are normal indicating that the defect occurs after PGC formation. We propose that Xdazl is required for early PGC differentiation and is indirectly necessary for the migration of PGCs through the endoderm. As an RNA-binding protein, Xdazl may regulate translation or expression of factors that mediate migration of PGCs.
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González, Candela Rocío, Luciana Moverer, Ricardo Saúl Calandra, Silvia Inés González-Calvar, and Alfredo Daniel Vitullo. "Age-related and photoperiodic variation of the DAZ gene family in the testis of the Syrian hamster (Mesocricetus auratus)." Zygote 26, no. 2 (March 25, 2018): 127–34. http://dx.doi.org/10.1017/s0967199418000023.
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SummaryThe Deleted in AZoospermia (DAZ) gene family regulates the development, maturation and maintenance of germ cells and spermatogenesis in mammals. The DAZ family consists of two autosomal genes, Boule and Dazl (Daz-like), and the Daz gene on chromosome Y. The aim of this study was to analyze the localization of DAZL and BOULE during testicular ontogeny of the seasonal-breeding Syrian hamster, Mesocricetus auratus. We also evaluated the testicular expression of DAZ family genes under short- or long-photoperiod conditions. In the pre-pubertal and adult testis, DAZL protein was found mainly in spermatogonia. BOULE was found in the spermatogonia from 20 days of age and during the pre-pubertal and adult period it was also detected in spermatocytes and round spermatids. DAZL and BOULE expression in spermatogonia was strictly nuclear only in 20-day-old hamsters. We also detected the novel mRNA and protein expression of BOULE in Leydig cells. In adult hamsters, Dazl expression was increased in regressed testis compared with non-regressed testis and DAZL protein expression was restricted to primary spermatocytes in regressed testis. These results show that DAZL and BOULE are expressed in spermatogonia at early stages in the Syrian hamster, then both proteins translocate to the cytoplasm when meiosis starts. In the adult regressed testis, the absence of DAZL in spermatogonia might be related to the decrease in germ cell number, suggesting that DAZ gene family expression is involved in changes in seminiferous epithelium during photoregression.
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Chagnon, G., G. Marckmann, and E. Verron. "A Comparison of the Hart-Smith Model with Arruda-Boyce and Gent Formulations for Rubber Elasticity." Rubber Chemistry and Technology 77, no. 4 (September 1, 2004): 724–35. http://dx.doi.org/10.5254/1.3547847.
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Abstract The present paper demonstrates that the Hart-Smith constitutive model and the more recent Arruda and Boyce eight chains and Gent constitutive models are closely related. The ability of these three models to predict both small and large strain responses of rubbers is highlighted and equations that relate their material parameters are established.
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Boyce, Mary C. "Direct Comparison of the Gent and the Arruda-Boyce Constitutive Models of Rubber Elasticity." Rubber Chemistry and Technology 69, no. 5 (November 1, 1996): 781–85. http://dx.doi.org/10.5254/1.3538401.
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Abstract The Arruda and Boyce eight-chain network constitutive model for rubber elastic materials is compared to the new Gent constitutive model for rubber elasticity. The salient features of each of the two models are compared. The ability of both models to predict three dimensional large strain deformation is demonstrated showing the near equivalence of these two model constructions as well as their abilities to predict complex three-dimensional deformation with only two material constants.
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Shah, Syed Mohmad, Neha Saini, Syma Ashraf, Manoj Kumar Singh, Radhey Sham Manik, Suresh Kumar Singla, Prabhat Palta, and Manmohan Singh Chauhan. "Cumulus cell-conditioned medium supports embryonic stem cell differentiation to germ cell-like cells." Reproduction, Fertility and Development 29, no. 4 (2017): 679. http://dx.doi.org/10.1071/rd15159.
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Cumulus cells provide cellular interactions and growth factors required for oogenesis. In vitro studies of oogenesis are limited primarily because of the paucity of their source, first trimester fetal gonads, and the small number of germ lineage precursor cells present within these tissues. In order to understand this obscure but vitally important process, the present study was designed to direct differentiation of embryonic stem (ES) cells into germ lineage cells. For this purpose, buffalo ES cells were differentiated, as embryoid bodies (EBs) and monolayer adherent cultures, in the presence of different concentrations of cumulus-conditioned medium (CCM; 10%, 20% and 40%) for different periods of culture (4, 8 and 14 days) to identify the optimum differentiation-inducing concentration and time. Quantitative polymerase chain reaction analysis revealed that 20%–40% CCM induced the highest expression of primordial germ cell-specific (deleted in Azoospermia- like (Dazl), dead (Asp-Glu-Ala-Asp) box polypeptide 4 (Vasa also known as DDX4) and promyelocytic leukemia zinc finger protein (Plzf)); meiotic (synaptonemal complex protein 3 (Sycp3), mutl homolog I (Mlh1), transition protein 1/2 (Tnp1/2) and protamine 2 (Prm2); spermatocyte-specific boule-like RNA binding protein (Boule) and tektin 1 (Tekt1)) and oocyte-specific growth differentiation factor 9 (Gdf9) and zona pellucida 2 /3 (Zp2/3)) genes over 8–14 days in culture. Immunocytochemical analysis revealed expression of primordial germ cell (c-KIT, DAZL and VASA), meiotic (SYCP3, MLH1 and PROTAMINE 1), spermatocyte (ACROSIN and HAPRIN) and oocyte (GDF9 and ZP4) markers in both EBs and monolayer differentiation cultures. Western blotting revealed germ lineage-specific protein expression in Day 14 EBs. The significantly lower (P < 0.05) concentration of 5-methyl-2-deoxycytidine in differentiated EBs compared to undifferentiated EBs suggests that methylation erasure may have occurred. Oocyte-like structures obtained in monolayer differentiation stained positive for ZONA PELLUCIDA protein 4 and progressed through various embryo-like developmental stages in extended cultures.
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Lima, David Baruc Cruvinel, Lúcia Daniel Machado da Silva, Paul Marinari, and Pierre Comizzoli. "Long-Term Preservation of Testicular Tissue Integrity and Viability Using Vitrification in the Endangered Black-Footed Ferret (Mustela nigripes)." Animals 10, no. 10 (October 13, 2020): 1865. http://dx.doi.org/10.3390/ani10101865.
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Systematic cryo-banking of semen and testicular tissues is critical to preserve the genetic value of recently deceased or neutered black-footed ferrets (BFFs). Specifically, recovering or producing mature sperm cells from vitrified-warmed issues offers additional options in assisted reproduction. This could, in turn, enhance the genetic management of this rare and endangered species over multiple generations. The objective of the study was to evaluate structural properties, DNA fragmentation, cell viability, and germ cell composition in vitrified testicular tissues from BFFs directly after warming or after warming plus a short in vitro culture period. Tissue biopsies from five adult BFFs were either kept fresh or vitrified with a standard protocol (using dimethylsulphoxide (DMSO) and glycerol) and warmed at 50 °C for 5 s. Some of the warmed samples were then cultured in vitro for 24 h. Fresh, warmed, and warmed/cultured tissues were analyzed using different indicators: histology of seminiferous tubules, intact Sertoli cells (vimentin labeling), DNA integrity, cell viability, germ cell composition (Oct4 and Boule labeling). Percentages of intact seminiferous tubules decreased after vitrification/warming and returned to the level of fresh samples after culture. While percentages of cells labeled with vimentin, with intact DNA integrity, or proportions of viable cells were affected by vitrification/warming, they all reached similar or better levels than the fresh tissue after culture. Proportions of cells labeled with Boule antibodies also improved during in vitro culture post-warming. We demonstrated for the first time that BFF testes subjected to vitrification, rapid warming, and short in vitro culture were viable and maintained the ability to resume germ cell progression. Cryopreserved testicular tissues could potentially contribute to new strategies to enhance BFF assisted reproduction as well as conservation efforts.
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Zhang, Jian, Xiao Han, Jin Wang, Bing-Zheng Liu, Jin-Liang Wei, Wei-Jie Zhang, Zhi-Hui Sun, and Ya-Qing Chang. "Molecular Cloning and Sexually Dimorphic Expression Analysis of nanos2 in the Sea Urchin, Mesocentrotus nudus." International Journal of Molecular Sciences 20, no. 11 (June 1, 2019): 2705. http://dx.doi.org/10.3390/ijms20112705.
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Sea urchin (Mesocentrotus nudus) is an economically important mariculture species in China and the gonads are the solely edible parts to human. The molecular mechanisms of gonad development have attracted increasing attention in recent years. Although the nanos2 gene has been identified as a germ cell marker in several invertebrates, little is known about nanos2 in adult sea urchins. Hereinto, we report the characterization of Mnnano2, an M. nudus nanos2 homology gene. Mnnanos2 is a maternal factor and can be detected continuously during embryogenesis and early ontogeny. Real-time quantitative PCR (RT-qPCR) and section in situ hybridization (ISH) analysis revealed a dynamic and sexually dimorphic expression pattern of Mnnano2 in the gonads. Its expression reached the maximal level at Stage 2 along with the gonad development in both ovary and testis. In the ovary, Mnnanos2 is specifically expressed in germ cells. In contrast, Mnnanos2 is expressed in both nutritive phagocytes (NP) cells and male germ cells in testis. Moreover, knocking down of Mnnanos2 by means of RNA interference (RNAi) reduced nanos2 and boule expression but conversely increased the expression of foxl2. Therefore, our data suggest that Mnnanos2 may serve as a female germ cell marker during gametogenesis and provide chances to uncover its function in adult sea urchin.
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Del Vento, Federico, Maxime Vermeulen, Bernard Ucakar, Jonathan Poels, Anne des Rieux, and Christine Wyns. "Significant Benefits of Nanoparticles Containing a Necrosis Inhibitor on Mice Testicular Tissue Autografts Outcomes." International Journal of Molecular Sciences 20, no. 23 (November 20, 2019): 5833. http://dx.doi.org/10.3390/ijms20235833.
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Fertility preservation for prepubertal boys relies exclusively on cryopreservation of immature testicular tissue (ITT) containing spermatogonia as the only cells with reproductive potential. Preclinical studies that used a nude mice model to evaluate the development of human transplanted ITT were characterized by important spermatogonial loss. We hypothesized that the encapsulation of testicular tissue in an alginate matrix supplemented with nanoparticles containing a necrosis inhibitor (NECINH-NPS) would improve tissue integrity and germ cells’ survival in grafts. We performed orthotopic autotransplantation of 1 mm³ testicular tissue fragments recovered form mice (aged 4–5 weeks). Fragments were either non-encapsulated, encapsulated in an alginate matrix, or encapsulated in an alginate matrix containing NECINH-NPs. Grafts were recovered 5- and 21-days post-transplantation. We evaluated tissue integrity (hematoxylin-eosin staining), germ cells survival (immunohistochemistry for promyelocytic leukemia zinc-finger, VASA, and protein-boule-like), apoptosis (immunohistochemistry for active-caspase 3), and lipid peroxidation (immunohistochemistry for malondialdehyde). NECINH-NPs significantly improved testicular tissue integrity and germ cells’ survival after 21 days. Oxidative stress was reduced after 5 days, regardless of nanoparticle incorporation. No effect on caspase-dependent apoptosis was observed. In conclusion, NECINH-NPs in an alginate matrix significantly improved tissue integrity and germ cells’ survival in grafts with the perspective of higher reproductive outcomes.
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ReijoPiera, R. A. "006. HUMAN GERM CELL FORMATION AND DIFFERENTIATION FROM PLURIPOTENT STEM CELLS." Reproduction, Fertility and Development 22, no. 9 (2010): 5. http://dx.doi.org/10.1071/srb10abs006.
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Human embryo development begins with the fusion of egg and sperm, followed by reprogramming of the DNA, a series of cell divisions and activation of the embryo’s genome. As development continues, the germ cells (egg and sperm) must be set aside from other cell types. A major cause of infertility in men and women is quantitative and qualitative defects in human germ cell (oocyte and sperm) development. Yet, it has been difficult to study human germ cell development, especially features that are unique relative to model organisms. We have developed a system to differentiate human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) to germ cells and to quantitate and isolate primordial germ cells (PGCs) derived from both XX- and XY-bearing hESCs and iPSCs. This allowed silencing and overexpression of genes that encode germ cell-specific cytoplasmic RNA-binding proteins (not transcription factors) and resulted in the modulation of human male and female germ cell formation and developmental progression. We observed that human DAZL (Deleted in AZoospermia-Like) functions in female and male PGC formation and maintenance, whereas closely-related family members, BOULE and DAZ, promote entry into meiosis and development of haploid gametes with sperm-specific methylation patterns at imprinted loci in the male. We also conducted critical proof-of-concept studies in mice that showed that phenotypes observed in germ cell development in vitro from wildtype, heterozygous, and Dazl–/– mutation-carrying mouse ESCs (mESCs) mirrored the phenotypes that were observed in vivo. Furthermore, transplantation of XX mESC-derived oocytes resulted in recruitment of somatic cells to form follicles. These studies comprised the first direct experimental analysis of the genetics of human germ cell development and set the stage for extensive exploration of complex genetic variants linked to infertility. Results are significant to the generation of gametes for developmental genetic studies and potential clinical applications.
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Carroll, Michael M. "Molecular chain networks and strain energy functions in rubber elasticity." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2144 (March 18, 2019): 20180067. http://dx.doi.org/10.1098/rsta.2018.0067.
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A relatively simple molecular–statistical model for rubber elasticity, similar to the Wang–Guth and the Arruda–Boyce (AB) models, is presented. Discussion of some approximate inverse Langevin functions leads to the selection of a new one as the most attractive balance between accuracy and simplicity. Use of this approximation with the AB model, in particular, yields the logarithmic strain energy introduced by Gent that exhibits limiting chain extensibility. A rather unusual facet of the relationship between the three strain energies is that the new one is the mean of the other two. This article is part of the theme issue ‘Rivlin's legacy in continuum mechanics and applied mathematics’.
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Kee, Kehkooi, Vanessa T. Angeles, Martha Flores, Ha Nam Nguyen, and Renee A. Reijo Pera. "Human DAZL, DAZ and BOULE genes modulate primordial germ-cell and haploid gamete formation." Nature 462, no. 7270 (October 28, 2009): 222–25. http://dx.doi.org/10.1038/nature08562.
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Dwarakanath, Manali, Menghuat Lim, Hongyan Xu, and Yunhan Hong. "Differential expression of boule and dazl in adult germ cells of the Asian seabass." Gene 549, no. 2 (October 2014): 237–42. http://dx.doi.org/10.1016/j.gene.2014.07.068.
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Williams, Patrick A., Michael S. Krug, Emily A. McMillan, Jasmine D. Peake, Tara L. Davis, Simon Cocklin, and Todd I. Strochlic. "Phosphorylation of the RNA-binding protein Dazl by MAPKAP kinase 2 regulates spermatogenesis." Molecular Biology of the Cell 27, no. 15 (August 2016): 2341–50. http://dx.doi.org/10.1091/mbc.e15-11-0773.
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Developing male germ cells are exquisitely sensitive to environmental insults such as heat and oxidative stress. An additional characteristic of these cells is their unique dependence on RNA-binding proteins for regulating posttranscriptional gene expression and translational control. Here we provide a mechanistic link unifying these two features. We show that the germ cell–specific RNA-binding protein deleted in azoospermia-like (Dazl) is phosphorylated by MAPKAP kinase 2 (MK2), a stress-induced protein kinase activated downstream of p38 MAPK. We demonstrate that phosphorylation of Dazl by MK2 on an evolutionarily conserved serine residue inhibits its interaction with poly(A)-binding protein, resulting in reduced translation of Dazl-regulated target RNAs. We further show that transgenic expression of wild-type human Dazl but not a phosphomimetic form in the Drosophila male germline can restore fertility to flies deficient in boule, the Drosophila orthologue of human Dazl. These results illuminate a novel role for MK2 in spermatogenesis, expand the repertoire of RNA-binding proteins phosphorylated by this kinase, and suggest that signaling by the p38-MK2 pathway is a negative regulator of spermatogenesis via phosphorylation of Dazl.
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Jahani, Kamal, and Hossein Mahmoodzade. "Investigating the Performance of Hyperelastic Constitutive Models in Predicting Dynamic Characteristics of Elastomeric Components." Advanced Materials Research 889-890 (February 2014): 156–60. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.156.
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In this paper, the performance of different hyperelastic constitutive models namely Money-Rivlin, Gent, Ogden and Arruda-Boyce to predict the dynamic characteristic of elastomeric components is investigated. An elastomeric engine mount is chosen as case study. Material Parameters of the different models are extracted by curve fitting on uni-axial stress-strain test data. Both static and dynamic response of the finite element model considering the hyperelastic constitutive models are compared with their measured counterparts and each other. To obtain frequency response function of the component for each model, at first considering proportional damping for elastomeric media, the transient analysis due to impulse excitation is performed on the component and then using FFT transformation, the frequency response function is achieved. The results show that hyperelastic constitutive models can be implemented in predicting both static and dynamic behavior of elastomeric components.
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Xu, Hongyan, Zhendong Li, Mingyou Li, Li Wang, and Yunhan Hong. "Boule Is Present in Fish and Bisexually Expressed in Adult and Embryonic Germ Cells of Medaka." PLoS ONE 4, no. 6 (June 30, 2009): e6097. http://dx.doi.org/10.1371/journal.pone.0006097.
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Kim, Byunghyuk, and Kunsoo Rhee. "BOULE, a Deleted in Azoospermia Homolog, Is Recruited to Stress Granules in the Mouse Male Germ Cells." PLOS ONE 11, no. 9 (September 15, 2016): e0163015. http://dx.doi.org/10.1371/journal.pone.0163015.
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Zhang, Yan-Li, Pei-Zhen Li, Jing Pang, Yong-Jie Wan, Guo-Min Zhang, Yi-Xuan Fan, Zi-Yu Wang, Nie-Hai Tao, and Feng Wang. "Induction of goat bone marrow mesenchymal stem cells into putative male germ cells using mRNA for STRA8, BOULE and DAZL." Cytotechnology 71, no. 2 (February 14, 2019): 563–72. http://dx.doi.org/10.1007/s10616-019-00304-7.
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Li, Mingzhao, Meng Yu, Chao Liu, Haijing Zhu, and Jinlian Hua. "Expression of miR-34c in response to overexpression of Boule and Stra8 in dairy goat male germ line stem cells (mGSCs)." Cell Biochemistry and Function 31, no. 4 (March 19, 2013): 281–88. http://dx.doi.org/10.1002/cbf.2970.
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Kut, S., G. Ryzińska, and B. Niedziałek. "The Influence of Material Model of the Polyurethane Elastomer on the FEM Calculations Quality for the Various Modes of Loading." Archives of Metallurgy and Materials 62, no. 2 (June 1, 2017): 523–30. http://dx.doi.org/10.1515/amm-2017-0077.
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AbstractThe paper presents research to verify the effectiveness of nine selected material models of elastomeric materials based on uniaxial tension test. Basing on the cyclic uniaxial tension test of elastomers sample, the stress-strain characteristic for the 18th load cycle was prepared. On the basis of the obtained characteristic, the values of material constants were calculated for the studied models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow) and simulation of tensile, upsetting and bending processes was performed with the usage of the software MARC/Mentat. The effectiveness of the selected models was determined based on a comparison of results obtained in the experimental tensile test, upsetting test and bending test of an elastomeric samples with the results of numerical FEM calculations for each models. The research has shown that, for modeling of the elastomeric cylinder upsetting in the range of deformation of 62%, the best results with the comparison of the experiment were obtained by using the Yeoh model. In the bending process none of the analyzed models indicate a high convergence of results from an experiment. Analyzing the characteristics of the experimental and numerical tensile test it can be seen that in the entire range of punch movement (0 to 55 mm), models Signorini, Marlow, Ogden(N3) and Mooney(3) give the best results.
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Li, Pei-zhen, Guang-yao Yan, Le Han, Jing Pang, Bu-shuai Zhong, Guo-min Zhang, Feng Wang, and Yan-li Zhang. "Overexpression of STRA8, BOULE, and DAZL Genes Promotes Goat Bone Marrow–Derived Mesenchymal Stem Cells In Vitro Transdifferentiation Toward Putative Male Germ Cells." Reproductive Sciences 24, no. 2 (September 27, 2016): 300–312. http://dx.doi.org/10.1177/1933719116654990.
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Abofoul-Azab, Maram, Eitan Lunenfeld, Eliahu Levitas, Atif Zeadna, Johnny Younis, Shalom Bar-Ami, and Mahmoud Huleihel. "Identification of Premeiotic, Meiotic, and Postmeiotic Cells in Testicular Biopsies Without Sperm from Sertoli Cell-Only Syndrome Patients." International Journal of Molecular Sciences 20, no. 3 (January 22, 2019): 470. http://dx.doi.org/10.3390/ijms20030470.
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Sertoli cell-only syndrome (SCOS) affects about 26.3–57.8% of azoospermic men, with their seminiferous tubules containing only Sertoli cells. Recently, it was reported that testicular biopsies from nonobstructive azoospermic (NOA) patients contained germ cells, and that sperm could be found in the tubules of 20% of SCOS patients using testicular sperm extraction technology. Since the patients without sperm in their testicular biopsies do not have therapy to help them to father a biological child, in vitro maturation of spermatogonial stem cells (SSCs) isolated from their testis is a new approach for possible future infertility treatment. Recently, the induction of human and mice SSCs proliferation and differentiation was demonstrated using different culture systems. Our group reported the induction of spermatogonial cell proliferation and differentiation to meiotic and postmeiotic stages in mice, rhesus monkeys, and prepubertal boys with cancer using 3D agar and methylcellulose (MCS) culture systems. The aim of the study was to identify the type of spermatogenic cells present in biopsies without sperm from SCOS patients, and to examine the possibility of inducing spermatogenesis from isolated spermatogonial cells of these biopsies in vitro using 3D MCS. We used nine biopsies without sperm from SCOS patients, and the presence of spermatogenic markers was evaluated by PCR and specific immunofluorescence staining analyses. Isolated testicular cells were cultured in MCS in the presence of StemPro enriched media with different growth factors and the development of colonies/clusters was examined microscopically. We examined the presence of cells from the different stages of spermatogenesis before and after culture in MCS for 3–7 weeks. Our results indicated that these biopsies showed the presence of premeiotic markers (two to seven markers/biopsy), meiotic markers (of nine biopsies, cAMP responsive element modulator-1 (CREM-1) was detected in five, lactate dehydrogenase (LDH) in five, and BOULE in three) and postmeiotic markers (protamine was detected in six biopsies and acrosin in three). In addition, we were able to induce the development of meiotic and/or postmeiotic stages from spermatogonial cells isolated from three biopsies. Thus, our study shows for the first time the presence of meiotic and/or postmeiotic cells in biopsies without the sperm of SCOS patients. Isolated cells from some of these biopsies could be induced to meiotic and/or postmeiotic stages under in vitro culture conditions.
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Íñiguez-Macedo, Saúl, Rubén Lostado-Lorza, Rubén Escribano-García, and María Martínez-Calvo. "Finite Element Model Updating Combined with Multi-Response Optimization for Hyper-Elastic Materials Characterization." Materials 12, no. 7 (March 27, 2019): 1019. http://dx.doi.org/10.3390/ma12071019.
Full textAbstract:
The experimental stress-strain curves from the standardized tests of Tensile, Plane Stress, Compression, Volumetric Compression, and Shear, are normally used to obtain the invariant λi and constants of material Ci that will define the behavior elastomers. Obtaining these experimental curves requires the use of expensive and complex experimental equipment. For years, a direct method called model updating, which is based on the combination of parameterized finite element (FE) models and experimental force-displacement curves, which are simpler and more economical than stress-strain curves, has been used to obtain the Ci constants. Model updating has the disadvantage of requiring a high computational cost when it is used without the support of any known optimization method or when the number of standardized tests and required Ci constants is high. This paper proposes a methodology that combines the model updating method, the mentioned standardized tests and the multi-response surface method (MRS) with desirability functions to automatically determine the most appropriate Ci constants for modeling the behavior of a group of elastomers. For each standardized test, quadratic regression models were generated for modeling the error functions (ER), which represent the distance between the force-displacement curves that were obtained experimentally and those that were obtained by means of the parameterized FE models. The process of adjusting each Ci constant was carried out with desirability functions, considering the same value of importance for all of the standardized tests. As a practical example, the proposed methodology was validated with the following elastomers: nitrile butadiene rubber (NBR), ethylene-vinyl acetate (EVA), styrene butadiene rubber (SBR) and polyurethane (PUR). Mooney–Rivlin, Ogden, Arruda–Boyce and Gent were considered as the hyper-elastic models for modeling the mechanical behavior of the mentioned elastomers. The validation results, after the Ci parameters were adjusted, showed that the Mooney–Rivlin model was the hyper-elastic model that has the least error of all materials studied (MAEnorm = 0.054 for NBR, MAEnorm = 0.127 for NBR, MAEnorm = 0.116 for EVA and MAEnorm = 0.061 for NBR). The small error obtained in the adjustment of the Ci constants, as well as the computational cost of new materials, suggests that the methodology that this paper proposes could be a simpler and more economical alternative to use to obtain the optimal Ci constants of any type of elastomer than other more sophisticated methods.
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KITLV, Redactie. "Book reviews." New West Indian Guide / Nieuwe West-Indische Gids 84, no. 3-4 (January 1, 2010): 277–344. http://dx.doi.org/10.1163/13822373-90002444.
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The Atlantic World, 1450-2000, edited by Toyin Falola & Kevin D. Roberts (reviewed by Aaron Spencer Fogleman) The Slave Ship: A Human History, by Marcus Rediker (reviewed by Justin Roberts) Extending the Frontiers: Essays on the New Transatlantic Slave Trade Database, edited by David Eltis & David Richardson (reviewed by Joseph C. Miller) "New Negroes from Africa": Slave Trade Abolition and Free African Settlement in the Nineteenth-Century Caribbean, by Rosanne Marion Adderley (reviewed by Nicolette Bethel) Atlantic Diasporas: Jews, Conversos, and Crypto-Jews in the Age of Mercantilism, 1500-1800, edited by Richard L. Kagan & Philip D. Morgan (reviewed by Jonathan Schorsch) Brother’s Keeper: The United States, Race, and Empire in the British Caribbean, 1937-1962, by Jason C. Parker (reviewed by Charlie Whitham) Labour and the Multiracial Project in the Caribbean: Its History and Promise, by Sara Abraham (reviewed by Douglas Midgett) Envisioning Caribbean Futures: Jamaican Perspectives, by Brian Meeks (reviewed by Gina Athena Ulysse) Archibald Monteath: Igbo, Jamaican, Moravian, by Maureen Warner-Lewis (reviewed by Jon Sensbach) Left of Karl Marx: The Political Life of Black Communist Claudia Jones, by Carole Boyce Davies (reviewed by Linden Lewis) Displacements and Transformations in Caribbean Cultures, edited by Lizabeth Paravisini-Gebert & Ivette Romero-Cesareo (reviewed by Bill Maurer) Caribbean Migration to Western Europe and the United States: Essays on Incorporation, Identity, and Citizenship, edited by Margarita Cervantes-Rodríguez, Ramón Grosfoguel & Eric Mielants (reviewed by Gert Oostindie) Home Cooking in the Global Village: Caribbean Food from Buccaneers to Ecotourists, by Richard Wilk (reviewed by William H. Fisher) Dead Man in Paradise: Unraveling a Murder from a Time of Revolution, by J.B. MacKinnon (reviewed by Edward Paulino) Tropical Zion: General Trujillo, FDR, and the Jews of Sosúa, by Allen Wells (reviewed by Michael R. Hall) Downtown Ladies: Informal Commercial Importers, a Haitian Anthropologist, and Self-Making in Jamaica, by Gina A. Ulysse (reviewed by Jean Besson) Une ethnologue à Port-au-Prince: Question de couleur et luttes pour le classement socio-racial dans la capitale haïtienne, by Natacha Giafferi-Dombre (reviewed by Catherine Benoît) Haitian Vodou: Spirit, Myth, and Reality, edited by Patrick Bellegarde-Smith & Claudine Michel (reviewed by Susan Kwosek) Cuba: Religion, Social Capital, and Development, by Adrian H. Hearn (reviewed by Nadine Fernandez) "Mek Some Noise": Gospel Music and the Ethics of Style in Trinidad, by Timothy Rommen (reviewed by Daniel A. Segal)Routes and Roots: Navigating Caribbean and Pacific Island Literatures, by Elizabeth M. DeLoughrey (reviewed by Anthony Carrigan) Claude McKay, Code Name Sasha: Queer Black Marxism and the Harlem Renaissance, by Gary Edward Holcomb (reviewed by Brent Hayes Edwards) The Sense of Community in French Caribbean Fiction, by Celia Britton (reviewed by J. Michael Dash) Imaging the Chinese in Cuban Literature and Culture, by Ignacio López-Calvo (reviewed by Stephen Wilkinson) Pre-Columbian Jamaica, by P. Allsworth-Jones (reviewed by William F. Keegan) Underwater and Maritime Archaeology in Latin America and the Caribbean, edited by Margaret E. Leshikar-Denton & Pilar Luna Erreguerena (reviewed by Erika Laanela)
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Sri Wahyuni, Siti Fadilah, and Adolf Bastian. "Children's independence Skills Analysis at Low Socioeconomic Environment." JPUD - Jurnal Pendidikan Usia Dini 14, no. 2 (November 30, 2020): 303–12. http://dx.doi.org/10.21009/jpud.142.08.
Full textAbstract:
Research suggests that child independence is more popular in countries with greater wealth and a higher percentage of the educated population. Various research implications expect children's independence and compliance to increase over time in developing countries. This study aims to describe the independence of early childhood who comes from low-income families or at low socioeconomic environment. Using quantitative descriptive, data collection techniques are carried out through a questionnaire. The study population was 30 respondents from the ECE institution who were included in the list of low-income families in 2018, using an area sampling technique. Overall, the teacher stated that all indicators of dependence on children from low-income families had reached the high category, which was 75%. The implication of further research is that aspects of independence in physical abilities, self-confidence, responsibility, discipline, sociability, sharing, and independence in terms of emotional control in early childhood can develop better in a low socio-economic environment.
Keywords: Early Childhood, Independence skills, low-socioeconomic environment
References
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Cirino, P. T., Miciak, J., Gerst, E., Barnes, M. A., Vaughn, S., Child, A., Huston-Warren, E., Coelho, V., Cadima, J., Pinto, A. I., Guimarães, C., Dark-Freudeman, A., West, R. L., Eisenberg, N., Sulik, M. J., Huh, Y., Reigeluth, C. M., Kim, S., Holloway, S. D., … Cheah, C. S. L. (2018). Attachment and self-regulation. Personality and Social Psychology Bulletin,16(2), 450–467. https://doi.org/10.1177/0022219415618497
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Saunders, PT, JM Turner, M. Ruggiu, M. Taggart, PS Burgoyne, D. Elliott, and HJ Cooke. "Absence of mDazl produces a final block on germ cell development at meiosis." Reproduction, November 1, 2003, 589–97. http://dx.doi.org/10.1530/rep.0.1260589.
Full textAbstract:
The autosomal gene DAZL is a member of a family of genes (DAZL, DAZ, BOULE), all of which contain a consensus RNA binding domain and are expressed in germ cells. Adult male and female mice null for Dazl lack gametes. In order to define more precisely the developmental stages in germ cells that require Dazl expression, the patterns of germ cell loss in immature male and female wild-type (+/+, WT) and Dazl -/- (DazlKO) mice were analysed. In females, loss of germ cells occurred during fetal life and was coincident with progression of cells through meiotic prophase. In males, testes were recovered from WT and DazlKO males obtained before and during the first wave of spermatogenesis (days 2-19). Mitotically active germ cells were present up to and including day 19. Functional differentiation of spermatogonia associated with detection of c-kit positive cells did not depend upon expression of Dazl. RBMY-positive cells (A, intermediate, B spermatogonia, zygotene and preleptotene spermatocytes) were reduced in DazlKO compared with WT testes. Staining of cell squashes from day 19 testes with anti-gamma-H2AX and anti-SCP3 antibodies showed that germ cells from DazlKO males were unable to progress beyond the leptotene stage of meiotic prophase I. It was concluded that in the absence of Dazl, germ cells can complete mitosis, and embark on functional differentiation but that, in both sexes, progression through meiotic prophase requires this RNA binding protein.
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Cordero, Paloma, Alejandra Guerrero-Moncayo, Monica De los Reyes, Manuel Varas-Godoy, Jahaira Cortez, Cristian G. Torres, Victor H. Parraguez, and Oscar A. Peralta. "Overexpression of DAZL, STRA8, and BOULE Genes and Treatment With BMP4 or Retinoic Acid Modulate the Expression of MSC Overexpressing Germ Cell Genes." Frontiers in Veterinary Science 8 (May 25, 2021). http://dx.doi.org/10.3389/fvets.2021.667547.
Full textAbstract:
In vitro gamete derivation from stem cells has potential applications in animal reproduction as an alternative method for the dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSCs) may be suitable candidates for in vitro gamete derivation considering their differentiative capacity and their potential for cell therapy. Due to its relevance in gametogenesis, it has been reported that retinoic acid (RA) and bone morphogenetic protein (BMP) 4 are able to upregulate the expression of specific markers associated to the early stages of germ cell (GCs) differentiation in bovine fetal MSCs (bfMSCs). In the present study, we used polycistronic vectors containing combinations of GC genes DAZL, STRA8, and BOULE followed by exposure to BMP4 or RA to induce GC differentiation of bovine fetal adipose tissue-derived MSC (AT-MSCs). Cells samples at Day 14 were analyzed according to the expression of pluripotent genes NANOG and OCT4 and GC genes DAZL, STRA8, BOULE, PIWI, c-KIT, and FRAGILIS using Q-PCR. Fetal and adult testis and AT-MSCs samples were also analyzed for the expression of DAZL, STRA8, and NANOG using immunofluorescence. Increased gene expression levels in the adult testis and cell-specific distribution of DAZL, STRA8, and NANOG in the fetal testis suggest that these markers are important components of the regulatory network that control the in vivo differentiation of bovine GCs. Overexpression of DAZL and STRA8 in bi-cistronic and DAZL, STRA8, and BOULE in tri-cistronic vectors resulted in the upregulation of OCT4, NANOG, and PIWIL2 in bovine fetal AT-MSCs. While BMP4 repressed NANOG expression, this treatment increased DAZL and c-KIT and activated FRAGILIS expression in bovine fetal AT-MSCs. Treatment with RA for 14 days increased the expression of DAZL and FRAGILIS and maintained the mRNA levels of STRA8 in bovine fetal AT-MSCs transfected with bi-cistronic and tri-cistronic vectors. Moreover, RA treatment repressed the expression of OCT4 and NANOG in these cells. Thus, overexpression of DAZL, STRA8, and BOULE induced the upregulation of the pluripotent markers and PIWIL2 in transfected bovine fetal AT-MSCs. The partial activation of GC gene expression by BMP4 and RA suggests that both factors possess common targets but induce different gene expression effects during GC differentiation in overexpressing bovine fetal AT-MSCs.
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Lawrence, S., M. Haddad, Z. Rosenwaks, and G. D. Palermo. "O-101 Neospermatogenesis benefits from a three-dimensional culture system." Human Reproduction 36, Supplement_1 (July 1, 2021). http://dx.doi.org/10.1093/humrep/deab125.071.
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Abstract Study question Does a three-dimensional (3D) culture system increase the efficiency of male germline differentiation of mouse embryonic stem cells (mESC) over a bidimensional method? Summary answer Our 3D culture system based on direct spherification proves superior to the standard bidimensional plating in promoting neogametogenesis of mESC into post-meiotic male germ cells. What is known already Two-dimensional monolayer cell cultures are common in stem cell research. However, this method does not replicate a physiological 3D spatial relationship and may provide an inaccurate replication of in vivo environments. A 3D spherical structure allows us to mimic the seminiferous tubule, the site of in vivo spermatogenesis. By using spheroids as a scaffold to replicate cell culture systems, we can study spermatogenesis in a controlled setting. Direct spherification, a technique commonly used in molecular gastronomy, provides an opportunity to create spheroids that mimic in vivo events that materialize in the lab Study design, size, duration mESCs were initially cultured on a 6-well plate coated with fibroblasts and inserted into sodium alginate spheres. To coax differentiation, spheres (3 to 6 mm in diameter) were plunged directly into differentiation medium (DM) while the control mESC in 6-well dishes were layered with it. Cells obtained from both culture systems were tested by biomarkers for different germ cell stages Participants/materials, setting, methods Bidimensional mESC at 80% confluence were differentiated either on a plate or spherified for a 3D culture. Both systems underwent the same timeline of exposure to EpiLC medium with Activin A, bFGF and KSR for 3 days and PGCLC medium with BMP4, LIF, SCF and EGF for 7 days. Differentiated cells were retrieved from each method at day 3 and day 10 to assess for germ line differentiation markers, DAZL, VASA and BOULE Main results and the role of chance Under optic visualization through the sphere wall, cellular aggregation was seen on day 2 of culturing in EpiLC medium while this phenomenon was not observed on bidimensional plating. In the conventional method, cells expressed 7% DAZL (spermatogonium cell stage) and 1% VASA (pre-spermatid cell stage) whereas in direct spherification, cells expressed 20% DAZL (P < 0.001) and 15% VASA positivity (P < 0.0001). To further compare the different methods in later stages of germ-line differentiation, the remaining spheres were cultured in PGCLC medium for 7 days. At day 10, isolated cells were assessed for VASA and DAZL again. In the conventional method, 23% of cells expressed positivity for VASA and 29% DAZL whereas direct spherification achieved a positivity rate of 43% for VASA (P < 0.005) and 45% for DAZL (P < 0.005). This increased expression in both VASA and DAZL signify the increased number of cells undergoing germline differentiation. Additionally, BOULE was assessed for the presence of meiotic cells such as the spermatocyte. The conventional method yielded < 1% BOULE positivity whereas in direct spherification, there was 10% positivity (P < 0.005). Direct spherifcation result shows that differentiation almost doubled in comparison to the conventional method, yielding more post-meiotic cells in the same amount of time Limitations, reasons for caution Despite a higher differentiation rate in direct spherification, these cells would still need to be tested for their fertilization potential. The ability to achieve fertilization, blastocysts and live pups would provide final proof and reliability of this method of neogametogenesis Wider implications of the findings Differentiating ESCs through direct spherification provides an alternative to studying intercellular relationships. This provides an opportunity to study spermatogenesis in more detail by replicating the microenvironment of the seminiferous tubule. Once embryo developmental competence of the de novo gamete is confirmed, this may open a new chapter in human reproduction Trial registration number N/A
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Kut, Stanislaw, Grazyna Ryzinska, and Bernadetta Niedzialek. "Numerical analysis and experimental verification of elastomer bending process with different material models." Open Engineering 6, no. 1 (January 1, 2016). http://dx.doi.org/10.1515/eng-2016-0029.
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Abstract The article presents the results of tests in order to verifying the effectiveness of the nine selected elastomeric material models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow), which the material constants were determined in one material test - the uniaxial tension testing. The convergence assessment of nine analyzed models were made on the basis of their performance from an experimental bending test of the elastomer samples from the results of numerical calculations FEM for each material models. To calculate the material constants for the analyzed materials, a model has been generated by the stressstrain characteristics created as a result of experimental uniaxial tensile test with elastomeric dumbbell samples, taking into account the parameters received in its 18th cycle. Using such a calculated material constants numerical simulation of the bending process of a elastomeric, parallelepipedic sampleswere carried out using MARC / Mentat program.
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Wex, Cora, Susann Arndt, Anke Stoll, Christiane Bruns, and Yuliya Kupriyanova. "Isotropic incompressible hyperelastic models for modelling the mechanical behaviour of biological tissues: a review." Biomedical Engineering / Biomedizinische Technik 60, no. 6 (January 1, 2015). http://dx.doi.org/10.1515/bmt-2014-0146.
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AbstractModelling the mechanical behaviour of biological tissues is of vital importance for clinical applications. It is necessary for surgery simulation, tissue engineering, finite element modelling of soft tissues, etc. The theory of linear elasticity is frequently used to characterise biological tissues; however, the theory of nonlinear elasticity using hyperelastic models, describes accurately the nonlinear tissue response under large strains. The aim of this study is to provide a review of constitutive equations based on the continuum mechanics approach for modelling the rate-independent mechanical behaviour of homogeneous, isotropic and incompressible biological materials. The hyperelastic approach postulates an existence of the strain energy function – a scalar function per unit reference volume, which relates the displacement of the tissue to their corresponding stress values. The most popular form of the strain energy functions as Neo-Hookean, Mooney-Rivlin, Ogden, Yeoh, Fung-Demiray, Veronda-Westmann, Arruda-Boyce, Gent and their modifications are described and discussed considering their ability to analytically characterise the mechanical behaviour of biological tissues. The review provides a complete and detailed analysis of the strain energy functions used for modelling the rate-independent mechanical behaviour of soft biological tissues such as liver, kidney, spleen, brain, breast, etc.
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Li, Pengyang, Dania Nanes Sarfati, Yuan Xue, Xi Yu, Alexander J. Tarashansky, Stephen R. Quake, and Bo Wang. "Single-cell analysis of Schistosoma mansoni identifies a conserved genetic program controlling germline stem cell fate." Nature Communications 12, no. 1 (January 20, 2021). http://dx.doi.org/10.1038/s41467-020-20794-w.
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AbstractSchistosomes are parasitic flatworms causing one of the most prevalent infectious diseases from which millions of people are currently suffering. These parasites have high fecundity and their eggs are both the transmissible agents and the cause of the infection-associated pathology. Given its biomedical significance, the schistosome germline has been a research focus for more than a century. Nonetheless, molecular mechanisms that regulate its development are only now being understood. In particular, it is unknown what balances the fate of germline stem cells (GSCs) in producing daughter stem cells through mitotic divisions versus gametes through meiosis. Here, we perform single-cell RNA sequencing on juvenile schistosomes and capture GSCs during de novo gonadal development. We identify a genetic program that controls the proliferation and differentiation of GSCs. This program centers around onecut, a homeobox transcription factor, and boule, an mRNA binding protein. Their expressions are mutually dependent in the schistosome male germline, and knocking down either of them causes over-proliferation of GSCs and blocks germ cell differentiation. We further show that this germline-specific regulatory program is conserved in the planarian, schistosome’s free-living evolutionary cousin, but the function of onecut has changed during evolution to support GSC maintenance.
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Kobayashi, Hideyuki, Koichi Nagao, Yusuke Oka, Masato Nagata, Fumito Yamabe, keiichiro Takasugi, Shuichi Kamimura, Norie Tanaka, Kuri Suzuki, and Koichi Nakajima. "2013 INTRODUCTION OF VASA, DAZL, DAZ3, AND BOULE IN THE DIRECT REPROGRAMMING OF GERM CELLS FROM FIBROBLASTS DERIVED FROM ADULT TESTIS TISSUE." Journal of Urology 185, no. 4S (April 2011). http://dx.doi.org/10.1016/j.juro.2011.02.2241.
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Borle, Sean. "Wear a Helmet! Healthy Safety Habits by M.E. Salzmann." Deakin Review of Children's Literature 5, no. 3 (January 29, 2016). http://dx.doi.org/10.20361/g28k5w.
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Salzmann, Mary Elizabeth. Wear a Helmet! Healthy Safety Habits. Minneapolis, MN: Abdo Publishing, 2015, Print.This small picture book is levelled to the third or “transitional” reading level defined in the Sandcastle series. This series is designed for use in “shared, guided and independent reading and writing activities to support a balanced approach to literacy instruction”. The subject of the book is health and safety. Each photograph shows a child doing something that promotes safety: wearing a bike helmet, a life preserver or a seatbelt. Other children are shown washing hands, using a pot holder and seated at a computer to illustrate online safety. The children featured are in the 7-9 age range and are named to allow readers to relate to them more easily. Younger children will look up to older children pictured doing the right things. The text is short and very simple, designed for children who are not yet fluent readers. However, for average readers, who might pick up this book in a library, the text would be most appropriate for the lower end of the recommended age 4-9 audience. There is a brief quiz at the end of the book, aimed at a low comprehension level. Strangely, some of the definitions in the glossary contain words that are well above the reading level of the book. For example, the definition of the word “germ” includes the word “organism”. While this book is designed for reading enhancement programs, it does model useful health and safety ideas, so would be a good addition for school and public libraries.Recommendation: 3 stars out of 4Reviewer: Sean BorleSean Borle is a University of Alberta undergraduate student who is an advocate for child health and safety.
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Vereecke, Gertjan, Justine Defreyne, Dorien Van Saen, Sarah Collet, Jo Van Dorpe, Guy T'Sjoen, and Ellen Goossens. "Characterisation of testicular function and spermatogenesis in transgender women." Human Reproduction, November 30, 2020. http://dx.doi.org/10.1093/humrep/deaa254.
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Abstract STUDY QUESTION Does gender-affirming treatment prevent full spermatogenesis in transgender women (TW)? SUMMARY ANSWER Adequate hormonal therapy (HT) leads to complete suppression of spermatogenesis in most TW, if serum testosterone levels within female reference ranges are obtained. WHAT IS KNOWN ALREADY Gender-affirming treatment in transgender individuals may involve gender-affirming HT. The effects on spermatogenesis in TW remain unclear. In order to add information from a referral centre for transgender care, we wish to compare results of earlier studies with our population of TW who received a standard hormone treatment. STUDY DESIGN, SIZE, DURATION This was a prospective cohort study part of the European Network for the Investigation of Gender Incongruence (ENIGI), conducted between 15 February 2010 and 30 September 2015. There were 162 TW were included in the ENIGI study at the Ghent University Hospital in Belgium. Participants are included in ENIGI when they first start HT, and follow-up visits occur over the next 3 years. PARTICIPANTS/MATERIALS, SETTING METHODS The study included 97 TW who initiated HT with cyproterone acetate (CPA) plus oestrogens and proceeded with gonadectomy at the Ghent University Hospital. Testicular tissue retrieved during gonadectomy was processed and stained for four different germ cell markers by the Biology of the Testis lab at the Vrije Universiteit Brussel. Subsequent immunohistochemical staining was performed for melanoma-associated antigen A4 (MAGE-A4, marker for spermatogonia and early spermatocytes), boule homologue, RNA-binding protein (BOLL, marker for secondary spermatocytes and round spermatids), cAMP-responsive element modulator (CREM, marker for round spermatids) and acrosin (marker for acrosome visualization). Serum levels of sex steroids were measured prior to surgery. MAIN RESULTS AND THE ROLE OF CHANCE Suppressed testosterone levels (<50 ng/dl) were found in 92% of the participants prior to surgery. The mean time between initiation of HT and surgery was 685 days. In 88% (85/97) of the sections, MAGE-A4 staining was positive. Further staining could not reveal complete spermatogenesis in any participant. LIMITATIONS, REASONS FOR CAUTION Testicular function of the participants prior to initiation of HT was not assessed, although all participants presented with cisgender male serum testosterone values before initiation of HT. The current study only reports on people using CPA at a fixed dose and may therefore not be applicable to all TW. WIDER IMPLICATIONS OF THE FINDINGS HT leads to complete suppression of spermatogenesis in most TW, if serum testosterone levels within female reference ranges are obtained. Serum testosterone levels are associated with the sperm maturation rate. It is important to discuss sperm preservation before the start of hormone therapy. If serum testosterone levels remain higher, spermatogenesis may still occur. STUDY FUNDING/COMPETING INTEREST(S) D.V.S. is a post-doctoral fellow of the Fonds Wetenschappelijk Onderzoek (FWO; 12M2819N). Processing of the testis specimens was funded by the Biology of The Testes (BITE) research group (Department of Reproduction, Genetics and Regenerative medicine at Vrije Universiteit Brussel (VUB)). There are no competing interests. TRIAL REGISTRATION NUMBER N/A.