The International Journal of Developmental Biology

Euskal Herriko Unibertsitateko Argitalpen Zerbitzua/Servicio Editorial de la Universidad del País Vasco.

Vol. 51/1, 2007

Más información en   http://www.ijdb.ehu.es/web/contents.php?vol=51&issue=1

Special Contribution

A history of normal plates, tables and stages in vertebrate embryology
Nick Hopwood
Department of History and Philosophy of Science, University of Cambridge, U.K.

Int. J. Dev. Biol. (2007) 51: 1-26

ABSTRACT: Developmental biology is today unimaginable without the normal stages that define standard divisions of development. This history of normal stages, and the related normal plates and normal tables, shows how these standards have shaped and been shaped by disciplinary change in vertebrate embryology. The article highlights the Normal Plates of the Development of the Vertebrates edited by the German anatomist Franz Keibel (16 volumes, 1897–1938). These were a major response to problems in the relations between ontogeny and phylogeny that amounted in practical terms to a crisis in staging embryos, not just between, but (for some) also within species. Keibel's design adapted a plate by Wilhelm His and tables by Albert Oppel in order to go beyond the already controversial comparative plates of the Darwinist propagandist Ernst Haeckel. The project responded to local pressures, including intense concern with individual variation, but recruited internationally and mapped an embryological empire. Though theoretically inconclusive, the plates became standard laboratory tools and forged a network within which the Institut International d'Embryologie (today the International Society of Developmental Biologists) was founded in 1911. After World War I, experimentalists, led by Ross Harrison and Viktor Hamburger, and human embryologists, especially George Streeter at the Carnegie Department of Embryology, transformed Keibel's complex, bulky tomes to suit their own contrasting demands. In developmental biology after World War II, normal stages—reduced to a few journal pages—helped domesticate model organisms. Staging systems had emerged from discussions that questioned the very possibility of assigning an embryo to a stage. The historical issues resonate today as developmental biologists work to improve and extend stage series, to make results from different laboratories easier to compare and to take individual variation into account.

Key words: history of embryology, Franz Keibel (1861­1929), normal plates, normal stages, standards

 
Original Articles

XSu(H)2 is an essential factor for gene expression and morphogenesis of the Xenopus gastrula embryo
Motoaki Ito, Tomohisa Katada, Seiji Miyatani and Tsutomu Kinoshita
Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan

Int. J. Dev. Biol. (2007) 51: 27-36
 

ABSTRACT: The CSL (CBF-1, Suppressor of Hairless, Lag-1) transcriptional factor is an important mediator of Notch signal transduction. It plays a key role in cell fate determination by cell-cell interaction. CSL functions as a transcriptional repressor before the activation of Notch signaling. However, once Notch signaling is activated, CSL is converted into a transcriptional activator. It remains unclear if CSL has any function during early development before neurogenesis, while transcriptional products exist from the maternal stage. Here, we analyzed the function of Xenopus Suppressor of Hairless (XSu(H)) using morpholino antisense oligonucleotides (MO), which interfere with the translation of transcripts. In Xenopus embryos, maternal transcripts of both XSu(H)1 and XSu(H)2 were ubiquitously observed until the blastula stage and thereafter only XSu(H)1 was zygotically transcribed. Knockdown experiments with MO demonstrated that XSu(H)2 depletion caused a decrease in the expression of the Xbrachyury, MyoD and JNK1 genes. Morphological and histological examinations indicated that XSu(H)2 depletion caused abnormal gastrulation, which resulted in severe defects of the notochord and somitic mesoderm. The effect of XSu(H)2-MO was completely rescued by co-injection of XSu(H)2 mRNAs, but not by XSu(H)1 mRNAs. XESR-1, a Notch signaling target gene, inhibited Xbrachyury expression. However, expression of the XESR-1 gene was not induced by depletion of XSu(H)2. Co-injection of the dominant-negative form of XESR-1 could not rescue the suppression of Xbrachyury expression in the XSu(H)2-depleted embryo. These results suggest that XSu(H)2 is involved in mesoderm formation and the cell movement of gastrula embryos in a different manner from the XESR-1-mediated Notch signaling pathway.

Key words: Suppressor of Hairless, notch signaling, gastrulation, Xbrachyury, XESR-1

Blood vessel/epicardial substance (bves) expression, essential for embryonic development, is down regulated by Grk/EFGR signalling
Shengyin Lin, Debiao Zhao and Mary Bownes
Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, U.K.

Int. J. Dev. Biol. (2007) 51: 37-44
 

ABSTRACT: The Pop1/Bves (blood vessel/epicardial substance) gene is a member of the popeye gene family recently identified in various species. It encodes a potential transmembrane glycoprotein and is a cell adhesion molecule present in skeletal and cardiac muscle and epithelia. We isolated the Drosophila homologue of Bves (DmBves) and found, using in situ hybridisation to RNA in ovaries, that bves is expressed in all follicular epithelial cells surrounding the oocyte at stage 10, except those in very posterior and anterior-dorsal regions adjacent to the oocyte. We show that the repression of bves expression in anterior-dorsal follicle cells is regulated by the Grk/EGFR signalling pathway. Bves is also expressed in nurse cells during oogenesis and its transcripts are then translocated into the oocyte. Expression of bves antisense RNA during oogenesis causes reduced viability in the resulting embryos. There is a failure in the migration of pole cells from the posterior towards the antero-dorsal side of the embryo, probably resulting from abnormal germband extension and we suggest that bves is essential for normal embryonic development.

Key words: bves, Grk signalling, Drosophila, oogenesis, embryonic development

Induction of reverse development in two marine Hydrozoans
Jürgen Schmich1, Yulia Kraus2, Doris De Vito1, Daria Graziussi1, Ferdinando Boero1 and Stefano Piraino1

1. Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università di Lecce, Italy              2. Department of Evolutionary Biology, Biological Faculty, Lomonosov Moscow State University, Russia

Int. J. Dev. Biol. (2007) 51: 45-56

ABSTRACT: Cnidarians are unique organisms in the animal kingdom because of their unequalled potential to undergo reverse development (RD). The life cycle of some species can temporarily shift ordinary, downstream development from zygote to adult into the opposite ontogenetic direction by back-transformation of some life stages. The potential for RD in cnidarians offers the possibility to investigate how integrative signalling networks operate to control directionality of ontogeny (reverse vs. normal development). Striking examples are found in some hydrozoans, where RD of medusa bud or liberated medusa stages leads to rejuvenation of the post-larval polyp stage. Artificial stress may determine ontogeny reversal. We describe here the results of experimental assays on artificial induction of RD by different chemical and physical inducers on two marine hydrozoans, Turritopsis dohrnii and Hydractinia carnea, showing a different potential for RD. A cascade of morphogenetic events occurs during RD by molecular mechanisms and cellular patterns recalling larval metamorphosis. For the first time, we show here that exposure to cesium chloride (CsCl), an inducer of larval metamorphosis, may also induce RD, highlighting similarities and differences between these two master ontogenetic processes in cnidarians.

Key words: Cnidaria, reverse development, CsCl, heat shock, chemical induction, metamorphosis

Stage-specific regulation of programmed cell death during oogenesis of the medfly Ceratitis capitata (Diptera, Tephritidae)
Athanassios D. Velentzas, Ioannis P. Nezis, Dimitrios J. Stravopodis, Issidora S. Papassideri and Lukas H. Margaritis
Faculty of Biology, Department of Cell Biology and Biophysics, University of Athens, Athens, Greece

Int. J. Dev. Biol. (2007) 51: 57-66

ABSTRACT: In the present study, we describe novel features of programmed cell death in developing egg chambers occurring during mid- and late-oogenesis of the medfly Ceratitis capitata. During mid-oogenesis, the spontaneously degenerated egg chambers exhibit typical characteristics of apoptotic cell death. Their nurse cells contain fragmented DNA and fragmented actin, as revealed by TUNEL assay and immunolabelling, respectively. In vitro caspase activity assays and immunostaining procedures demonstrated that the atretic egg chambers acquired high levels of caspase activity. Distinct features of autophagic cell death were also observed during C. capitata mid-oogenesis, as revealed by the monodansylcadaverine staining approach and ultrastructural examination performed by transmission electron microscopy. Additionally, atretic egg chambers exhibit an upregulation of lysosomal proteases, as demonstrated by a procathepsin L immunolabelling procedure. At the late stages of C. capitata oogenesis, apoptosis and autophagy coexist, manifesting cell death features that are similar to the ones mentioned above, being also chaperoned by the involvement of an altered cytochrome c conformational display. We propose that apoptosis and autophagy operate synergistically during C. capitata oogenesis for a more efficient elimination of the degenerated nurse cells and abnormal egg chambers.

Key words: apoptosis, autophagy, Ceratitis capitata, nurse cell, programmed cell death

 
Amniotic fluid induces rapid epithelialization in the experimentally ruptured fetal mouse palate - implications for fetal wound healing
Toshiya Takigawa1 and Kohei Shiota1,2

1. Department of Anatomy and Developmental Biology and 2. Congenital Anomaly Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan

Int. J. Dev. Biol. (2007) 51: 67-77

ABSTRACT: Cleft of the secondary palate is one of the most common congenital birth defects in humans. The primary cause of cleft palate formation is a failure of fusion of bilateral palatal shelves, but rupture of the once fused palate has also been suggested to take place in utero. The possibility of post-fusion rupture of the palate in humans has hardly been accepted, mainly because in all the cleft palate cases, the cleft palatal edge is always covered with intact epithelium. To verify whether the intrauterine environment of the fetus plays roles in wound healing when the once fused palate is torn apart, we artificially tore apart fetal mouse palates after fusion and cultivated them in culture medium with or without mouse or human amniotic fluid. We thereby found that the wounded palatal edge became completely covered with flattened epithelium after 36 hours in culture with amniotic fluid, but not in culture without amniotic fluid. Using histological and scanning electron microscopic analyses of the healing process, it was revealed that the epithelium covering the wound was almost exclusively derived from the adjacent nasal epithelium, but not from the oral epithelium. Such actions of amniotic fluid on the fetal wound were never simulated by exogenous epidermal growth factor (EGF), albumin, or both. In addition, the rapid epithelialization induced by amniotic fluid was not prevented by either PD168393 (an inhibitor of the EGF receptor-specific tyrosine kinase) or SB431542 (a specific inhibitor of TGFbeta receptor type I/ALK5). The present study provides new insights into the unique biological actions of amniotic fluid in the repair of injured fetal palate.

Key words: secondary palate, wound healing, epithelialization, amniotic fluid, post-fusion rupture

Short Communications

A change in response to Bmp signalling precedes ectodermal fate choice
Chris T. Dee, Abigail Gibson, Andrea Rengifo, Shun-Kuo Sun, Roger K. Patient and Paul J. Scotting
Institute of Genetics, University of Nottingham, QMC, Nottingham, UK

Int. J. Dev. Biol. (2007) 51: 79-84 
 

ABSTRACT: Bone morphogenetic protein (Bmp) signalling plays a central role in the decision of ectoderm to adopt either neural or non-neural fates. The effects of this signalling are seen at mid-gastrulation in the activation of genes such as the Gata factors and the repression of genes such as the SoxB1 transcription factors in the non-neural regions. Using zebrafish embryos, we show that this Bmp signalling does not repress the expression of these same neural markers just 2-3 hours earlier. Since expression of the Bmp signalling effector, Smad1, only begins during early gastrulation, we tested the role of Smad1 and Smad5 (which is maternally expressed) in controlling gene expression both before and during gastrulation. This showed that the absence of Smad1 does not explain the lack of response of neural genes to Bmp signalling at early stages. However, these experiments showed that expression of the non-neural marker, gata2, is mediated by Smad5 in the absence of Smad1 at early stages, but is dependent upon Smad1 at later stages. Hence, we have shown a dynamic change in the molecular machinery underlying the Bmp response in the ectoderm during gastrulation stages of development.

Key words: ectoderm, neural induction, Bmp, Smad, zebrafish

 
Enhanced development of porcine embryos cloned from bone marrow mesenchymal stem  cells
Hai-Feng Jin1, B. Mohana Kumar1, Jung-Gon Kim1, Hye-Jin Song1, Yeon-Ji Jeong1, Seong-Keun Cho2, Sivasankaran Balasubramanian1,3, Sang-Yong Choe1 and Gyu-Jin Rho1

1. Institute of Animal Medicine, College of Veterinary Medicine, 2. Division of Applied Life Science, Gyeongsang National University, Chinju, Republic of Korea and 3. Department of Clinics, Madras Veterinary College, Tamilnadu Veterinary and Animal Sciences University, Chennai, India

Int. J. Dev. Biol. (2007) 51: 85-90
 

ABSTRACT: In the present study, we have characterized an isolated population of porcine bone marrow mesenchymal stem cells (MSCs) for multilineage commitment and compared the developmental potential of cloned embryos with porcine MSCs and fetal fibroblasts (FFs). MSCs exhibited robust alkaline phosphatase activity and later transformed into mineralized nodules following osteoinduction. Furthermore, MSCs underwent adipogenic and chondrogenic differentiation by producing lipid droplets and proteoglycans, respectively. Primary cultures of FFs from a female fetus at ~30 day of gestation were established. Donor cells at 3-4 passage were employed for nuclear transfer (NT). Cell cycle analysis showed that the majority of MSCs in confluence were in the G0/G1 stage. Cumulus-oocyte complexes were matured and fertilized in vitro (IVF) as control. The cleavage rate was significantly (P<0.05) higher in IVF than in NT embryos with MSCs and FFs (84.5±4.6% vs. 52.2±5.4% and 50.8±5.2%, respectively). However, blastocyst rates in IVF and NT embryos derived from MSCs (20.6±2.5% and 18.4±3.0%) did not differ, but were significantly (P<0.05) higher than NT derived from FFs (9.5±2.1%). Total cell number and the ratio of ICM to total cells among blastocysts cloned from MSCs (34.4±5.2 and 0.38±0.08, respectively) were significantly (P<0.05) higher than those from FFs (22.6±5.5 and 0.18±0.12, respectively). Proportions of TUNEL positive cells in NT embryos from FFs (7.3±1.8%) were significantly (P<0.05) higher than in MSCs (4.6±1.3%) and IVF (2.5±0.9%). The results clearly demonstrate that multipotent bone marrow MSCs have a greater potential as donor cells than FFs in achieving enhanced production of cloned porcine embryos.

Key words: mesenchymal stem cells, nuclear transfer, porcine