International Journal of Developmental Biology最新文献

The history of science in Argentina is based on the enormous contribution that the great immigration of the 19th and 20th centuries produced in the country. The scientific and philosophical ideas and the role played especially by Italian scientists who arrived in the country produced a great impact on the different disciplines including Development Biology in emerging universities. The University of Tucumán pioneered the study of experimental biology, making important contributions to reproductive biology and to the early development of amphibians. The contribution of the Italian embryologist Armando Pisanó and the Argentinian Francisco D. Barbieri expanded the field to other universities and research centers located in Córdoba, La Plata, Bahía Blanca and Rosario. Given its strategic position, laboratories located in the city of Buenos Aires reached technological advances faster than others. Indeed, these laboratories saw the evolution from experimental biology to developmental genetics, renewing interest in this area. Currently, Developmental Biology brings together young researchers eager to consolidate regional and global collaboration networks that seek to help solve specific problems such as fertility, epigenetics, stem cells and tissue engineering.

The pocket protein family controls several cellular functions such as cell cycle, differentiation, and apoptosis, among others. However, its role in stress has been poorly explored. The roundworm Caenorhabditis elegans is a simple model organism whose genes are highly conserved during evolution. C. elegans has only one pocket protein, LIN-35; a retinoblastoma protein (pRB)-related protein similar to p130. To control the expression of some of its targets, LIN-35 interacts with E2F-DP (E2 transcription factor/dimerization partner complex) transcription factors and LIN-52, a member of SynMUV (Synthetic Muv) complex. Together, these proteins form the DRM complex, which is also known as the DREAM complex in mammals. In this review, we will focus on the role of LIN-35 and its partners in the stress response. It has been shown that LIN-35 is required to control starvation in L1 and L4 larval stages, and to induce starvation-induced germ apoptosis. Remarkably, during L1 starvation, insulin/IGF-1 receptor signaling (IIS), as well as the pathogenic, toxin, and oxidative stress-responsive genes, are repressed by LIN-35. The lack of lin-35 also triggers a downregulation of oxidative stress genes. Recent works showed that lin-35 and hpl-2 mutant animals showed enhanced resistance to UPR^ER. Additionally, hpl-2 mutant animals also exhibited upregulation of autophagic genes, suggesting that SynMuv/DRM proteins participate in this process. Finally, lin-35(n745) mutant animals overexpressed hsp-6, a chaperone that participated in the UPR^mt. All of these data demonstrate that LIN-35 and its partners play an important role during the stress response.

Cell fusion is a process in which cells unite their membranes and cytoplasm. It is fundamental for sexual reproduction and embryonic development. Among the best-known cell fusion processes during animal development are fertilization, myoblast fusion, osteoclast generation, and vulva formation in Caenorhabditis elegans. Although it is involved in many other functions in unicellular and multicellular organisms, little is known about the mechanisms of cell fusion and the genes that code for the proteins participating in this process. Benjamin Podbilewicz has dedicated many years to understanding the processes and mechanisms of cell fusion. In this interview, he spoke to us about how he began his studies of this process, his contributions to this exciting field, his scientific ties with Ibero-America and his strategies for a well-balanced scientific/personal life.

The axolotl (Ambystoma mexicanum) has been a widely studied organism due to its capacity to regenerate most of its cells, tissues and whole-body parts. Since its genome was sequenced, several molecular tools have been developed to study the mechanisms behind this outstanding and extraordinary ability. The complexity of its genome due to its sheer size and the disproportionate expansion of a large number of repetitive elements, may be a key factor at play during tissue remodeling and regeneration mechanisms. Transcriptomic analysis has provided information to identify candidate genes networks and pathways that might define successful or failed tissue regeneration. Nevertheless, the epigenetic machinery that may participate in this phenomenon has largely not been studied. In this review, we outline a broad overview of both genetic and epigenetic molecular processes related to regeneration in axolotl, from the macroscopic to the molecular level. We also explore the epigenetic mechanisms behind regenerative pathways, and its potential importance in future regeneration research. Altogether, understanding the genomics and global regulation in axolotl will be key for elucidating the special biology of this organism and the fantastic phenomenon that is regeneration.

Hydra, a Cnidarian believed to have been evolved about 60 million years ago, has been a favorite model for developmental biologists since Abraham Trembley introduced it in 1744. However, the modern renaissance in research on hydra was initiated by Alfred Gierer when he established a hydra laboratory at the Max Plank Institute in Göttingen in the late 1960s. Several signaling mechanisms that regulate development and pattern formation in vertebrates, including humans, have been found in hydra. These include Wnt, BMP, VEGF, FGF, Notch, and RTK signaling pathways. We have been using hydra to understand the evolution of cell signaling for the past several years. In this article, I will summarize the work on cell signaling pathways in hydra with emphasis on our own work. We have identified and characterized, for the first time, the hydra homologs of the BMP inhibitors Noggin and Gremlin, the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and several receptor tyrosine kinases (RTKs). Our work, along with that of others, clearly demonstrates that these pathways arose early in evolution to carry out functions that were often quite different from their functions in more complex animals. Apart from providing insights into morphogenesis and pattern formation in adult, budding and regenerating hydra, these findings bring out the utility of hydra as a model system to study evolutionarily ancient, in contrast to recently acquired, functions of various biological molecules.

Differential specification of dorsal flight appendages, wing and haltere, in Drosophila provides an excellent model system to address a number of important questions in developmental biology at the levels of molecules, pathways, tissues, organs, organisms and evolution. Here we discuss the mechanism by which the Hox protein Ubx recognizes and regulates its downstream targets, implications of the same in growth control at cellular and organ level and finally the evolution of haltere from ancestral hindwings in other holometabolous insects.

Drosophila hemocytes are majorly associated with immune responses, but they also undertake several non-immune functions that are crucial during various stages of development. The activity and behaviour of hemocytes are least documented during the metamorphic phase of fly development. Here we describe the activity, form and behaviour of the most abundant type of hemocyte in Drosophila melanogaster, the "plasmatocyte," throughout pupal development. Our study reveals different forms of plasmatocytes laden with varying degrees of histolyzing debris (muscle and fat) which extend beyond the size of the cell itself, highlighting the phagocytic capacity of these plasmatocytes. Interestingly, the engulfment of apoptotic debris by plasmatocytes is an actin-dependent process, and by the end of metamorphosis, clearance is achieved. The uptake of apoptotic debris consisting of muscles and lipids by the plasmatocytes provides us a model that can be employed to dissect out the relevant components of macroendocytosis and lipid-loaded phagocytosis. This understanding, by itself, is crucial for addressing the emerging role of phagocytes in physiology and pathophysiology.

Professor Panchanan Maheshwari served as Professor and Head of the Department of Botany, University of Delhi, from 1950 to 1966 and built an internationally reputed School of integrated plant embryology. Studies carried out during and after Maheshwari's period from this School have enormously advanced our knowledge of the structural, developmental and functional aspects of embryological processes. This review covers studies carried out at the Delhi School on the developmental biology of dispersed pollen grains which operate from pollen dispersal from the anthers until pollen tubes discharge the male gametes in the embryo sac for fertilization. These events include pollen viability and vigour, pollen germination and pollen tube growth, structural details of the pistil relevant to pollen function, pollination and pollen-pistil interaction.

During limb development, skeletal tissues differentiate from their progenitor cells in an orchestrated manner. Mesenchymal stromal cells (MSCs), which are considered to be adult undifferentiated/progenitor cells, have traditionally been identified by the expression of MSC-associated markers (MSC-am) and their differentiation capacities. However, although MSCs have been isolated from bone marrow and a variety of adult tissues, their developmental origin is poorly understood. Remarkably, adult MSCs share similar differentiation characteristics with limb progenitors. Here, we determined the expression patterns of common MSC-am throughout mouse hindlimb development. Our results demonstrate that MSC-am expression is not restricted to undifferentiated cells in vivo. Results from the analysis of MSC-am spatiotemporal expression in the embryonic hindlimb allowed us to propose five subpopulations which represent all limb tissues that potentially correspond to progenitor cells for each lineage. This work contributes to the understanding of MSC-am expression dynamics throughout development and underlines the importance of considering their expression patterns in future MSC studies of the limb.

The regulation of growth and the determination of organ-size in animals is an area of research that has received much attention during the past two and a half decades. Classic regeneration and cell-competition studies performed during the last century suggested that for size to be determined, organ-size is sensed and this sense of size feeds back into the growth control mechanism such that growth stops at the "correct" size. Recent work using Drosophila imaginal discs as a system has provided a particularly detailed cellular and molecular understanding of growth. Yet, a clear mechanistic basis for size-sensing has not emerged. I re-examine these studies from a different perspective and ask whether there is scope for alternate modes of size control in which size does not need to be sensed.