Current Proteomic and Metabolomic Knowledge of Zygotic and Somatic Embryogenesis in Plants

Embryogenesis is the primary developmental program in plants. The mechanisms that underlie the regulation of embryogenesis are an essential research subject given its potential contribution to mass in vitro propagation of profitable plant species. Somatic embryogenesis (SE) refers to the use of in vitro techniques to mimic the sexual reproduction program known as zygotic embryogenesis (ZE). In this review, we synthesize the current state of research on proteomic and metabolomic studies of SE and ZE in angiosperms (monocots and dicots) and gymnosperms. The most striking finding was the small number of studies addressing ZE. Meanwhile, the research effort focused on SE has been substantial but disjointed. Together, these research gaps may explain why the embryogenic induction stage and the maturation of the somatic embryo continue to be bottlenecks for efficient and large-scale regeneration of plants. Comprehensive and integrative studies of both SE and ZE are needed to provide the molecular foundation of plant embryogenesis, information which is needed to rationally guide experimental strategies to solve SE drawbacks in each species.

Regeneration in Stentor coeruleus

We often think about regeneration in terms of replacing missing structures, such as organs or tissues, with new structures generated via cell proliferation and differentiation. But at a smaller scale, single cells, themselves, are capable of regenerating when part of the cell has been removed. A classic model organism that facilitates the study of cellular regeneration in the giant ciliate Stentor coeruleus. These cells, which can grow to more than a millimeter in size, have the ability to survive after extensive wounding of their surface, and are able to regenerate missing structures. Even a small piece of a cell can regenerate a whole cell with normal geometry, in a matter of hours. Such regeneration requires cells to be able to trigger organelle biogenesis in response to loss of structures. But subcellular regeneration also relies on intracellular mechanisms to create and maintain global patterning within the cell. These mechanisms are not understood, but at a conceptual level they involve processes that resemble those seen in animal development and regeneration. Here we discuss single-celled regeneration in Stentor from the viewpoint of standard regeneration paradigms in animals. For example, there is evidence that regeneration of the oral apparatus in Stentor follows a sender-receiver model similar to crustacean eyestalk regeneration. By drawing these analogies, we find that many of the concepts already known from the study of animal-scale regeneration and development can be applied to the study of regeneration at the cellular level, such as the concepts of determination, induction, mosaic vs. regulative development, and epimorphosis vs. morphallaxis. We propose that the similarities may go beyond analogy, and that some aspects of animal development and regeneration may have evolved by exploiting pre-existing subcellular developmental strategies from unicellular ancestors.

Planning Urban Manufacturing, Industrial Building Typologies, and Built Environments: Lessons From Inner London

Despite concerns about the loss of industry, industrial land, and buildings in high-value post-industrial cities, there is concurrently a renewed enthusiasm around the potential of “new” urban manufacturing and its contribution to the socio-economic diversity of cities. Yet, little is known about how planning policy can best support the retention and growth of urban manufacturing. To advance this agenda, this article proposes that we need a better understanding of industrial building typologies and resultant urban form. Using concepts developed by Julienne Hanson to analyse residential morphologies undergoing transformation under modernism, we apply these concepts to investigate the industrial, mixed-use contexts in two areas of London with concentrations of urban manufacturing—Hackney Mare Street and Old Kent Road. The research presented examines how both areas have evolved historically to produce distinctive urban tissues and a range of industrial building typologies. The article reveals that, despite territorial similarities in the late 19th century, the mixed land uses and smaller plot sizes of Hackney Mare Street have allowed for a more resilient development pattern, whereas the greater separation of land uses, large plot sizes, and inward-facing development in the Old Kent Road has facilitated its reimagination for large-scale regeneration. We conclude that greater attention needs to be paid to the relationship between urban manufacturing and built urban form if policies that aim to protect or support the revival of manufacturing in cities are to avoid negative unintended consequences.

Causation of Saddleback Deformities in The Yellowfin Bream Acanthopagrus australis Fishery: Evidence of Physical Injury

The yellowfin bream A. australis supports an important commercial net and angling fishery on the east coast of Australia. Saddleback, a deformity of the dorsal fin and profile, occurs in this species, with the occurrence of fish with saddleback being as high as 10% in some areas. The present study provides new information and analysis of causation of the saddleback deformity in the yellowfin bream fishery. Lateral line scale regeneration due to injury, and soft tissue abnormalities indicative of deep wounding are present in yellowfin bream with saddleback. X-ray images of the entire skeleton of specimens with saddleback were also examined. An unpublished government report on chemical residues in saddleback and normal yellowfin bream is appended and discussed. The absence of both chemical residues, and lack of other skeletal deformities in yellowfin bream with saddleback provide indirect evidence of physical injury as the cause of saddleback in this case. The role of discarding of meshed yellowfin bream, which are smaller than the legal minimum size, as causation of the saddleback deformity is evaluated.

Poly(ADP-Ribose) Polymerase-3 Regulates Regeneration in Planarians

Protein ADP-ribosylation is a reversible post-translational modification (PTM) process that plays fundamental roles in cell signaling. The covalent attachment of ADP ribose polymers is executed by PAR polymerases (PARP) and it is essential for chromatin organization, DNA repair, cell cycle, transcription, and replication, among other critical cellular events. The process of PARylation or polyADP-ribosylation is dynamic and takes place across many tissues undergoing renewal and repair, but the molecular mechanisms regulating this PTM remain mostly unknown. Here, we introduce the use of the planarian Schmidtea mediterranea as a tractable model to study PARylation in the complexity of the adult body that is under constant renewal and is capable of regenerating damaged tissues. We identified the evolutionary conservation of PARP signaling that is expressed in planarian stem cells and differentiated tissues. We also demonstrate that Smed-PARP-3 homolog is required for proper regeneration of tissues in the anterior region of the animal. Furthermore, our results demonstrate, Smed-PARP-3(RNAi) disrupts the timely location of injury-induced cell death near the anterior facing wounds and also affects the regeneration of the central nervous system. Our work reveals novel roles for PARylation in large-scale regeneration and provides a simplified platform to investigate PARP signaling in the complexity of the adult body.

Analysis of regeneration mechanisms in auto ransplantation

Search for effective and available methods of stimulation of regenerative processes is a priority task of restorative medicine. Of high interest is a kind of biostimulation that induces activation of metabolic and reparative processes in the whole organism. Aim. Generalization of the relevant literature data concerning possible mechanisms of biostimulation in transplantation of self tissues of an organism. The results of literature survey showed that there still remain many debatable questions concerning cellular and molecular mechanisms that underlie intermolecular interactions in the stage of regeneration. Stimulating effects of an autotransplant both in the zone of the transplant or in an organism in whole may be caused by mediators and signal molecules released in destruction of the autotransplant tissues and of its perifocal region, and also by bioactive substances produced by immune-competent and stem cells. Conclusion. Tissue transplants may be used as inductors of production of biologically active substances and activators of immune and/or stromal cells. The latter, in turn, are producers of a number of chemical mediators required for large-scale regeneration. Therefore, a promising method of stimulation of regenerative processes is transplantation of self tissue. This method is characterized by simplicity, effectiveness and availability which evokes special interest and requires further study.

Sox9+ messenger cells orchestrate large-scale skeletal regeneration in the mammalian rib

Most bones in mammals display a limited capacity for natural large-scale repair. The ribs are a notable exception, yet the source of their remarkable regenerative ability remains unknown. Here, we identify a Sox9-expressing periosteal subpopulation that orchestrates large-scale regeneration of murine rib bones. Deletion of the obligate Hedgehog co-receptor, Smoothened, in Sox9-expressing cells prior to injury results in a near-complete loss of callus formation and rib bone regeneration. In contrast to its role in development, Hedgehog signaling is dispensable for the proliferative expansion of callus cells in response to injury. Instead, Sox9-positive lineage cells require Hh signaling to stimulate neighboring cells to differentiate via an unknown signal into a skeletal cell type with dual chondrocyte/osteoblast properties. This type of callus cell may be critical for bridging large bone injuries. Thus despite contributing to only a subset of callus cells, Sox9-positive progenitors play a major role in orchestrating large-scale bone regeneration.Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (<xref ref-type="decision-letter" rid="SA1">see decision letter</xref>).