Regenerating aggregates of hydra display unique cytoskeletal organisation that is absent in a regeneration-deficient strain

Hydra has the unique ability to regenerate from aggregates of dissociated single cells that lack positional information. We compared two strains of hydra, a strain of hydra that was capable of regenerating from aggregates and a strain of hydra that was deficient in this type of regeneration. We observed unique actin cytoskeletal arrangements that were present in the regenerates of regeneration-competent strain but not in the regeneration-deficient strain. Concomitantly, the regeneration-deficient strain failed to organise the extracellular cytoskeleton of laminin and collagen between ectodermal and endodermal epithelial cells. These interesting preliminary observations highlight the importance of the cytoskeletal organisation in regeneration of hydra and suggest that regeneration from the aggregates of dissociated cells through de novo patterning requires correct structural organisation of cytoskeletal elements.

Climate Change and the Circular Economy

The world is presently facing a climate catastrophe of its own making through the unabated increase in greenhouse gas emissions. Global consumption patterns are to blame, as presently, the global annual demand for resources outpaces the annual rate of the earth's ability to regenerate those resources. Thus, there is an urgent need to reduce the global demand for resources to a sustainable level, through the adoption of a circular economy. Individual consumption behavior habits form the basis of global consumption patterns, and therefore, adoption of sustainable consumption habits and lifestyles are necessary for addressing the climate crisis. In this chapter, the authors assess the potential for addressing the climate crisis through the adoption of a circular economy and sustainable consumption behavior. The authors also evaluate the extent of adoption of sustainable consumption behavior in India and make recommendations for adopting a circular economy in India.

Assessing Sustainability in Development Interventions

Sustainability is often claimed as an impact in development interventions although there is rarely a shared understanding of what it means, how to design for it, and especially how to assess the likelihood that intended streams of benefits will continue. This chapter asserts that to design and later to evaluate an intervention with sustainable impacts, the intervention must deepen indigenous capabilities to manage the program, to solve problems, and to innovate. The design and implementation also must operate within environmental boundaries, not extracting resources beyond the ability to regenerate or degrading environmental services—that is, design and implementation must incorporate the primacy of the environment. A postprogram evaluation 3–10 years after a program has ended provides evidence on whether the program is likely to have sustainable impacts. A case study of an asset transfer program in Malawi highlights the criteria for evaluating sustainability: deepened capabilities and social capital, reinvestment in program activities, and the development of backward and forward linkages catalyzing growing economic opportunities.

Notch inhibition promotes regeneration and immunosuppression supports cone survival in a zebrafish model of inherited retinal dystrophy

Photoreceptor degeneration leads to irreversible vision loss in humans with retinal dystrophies such as Retinitis Pigmentosa. Whereas photoreceptor loss is permanent in mammals, zebrafish possesses the ability to regenerate retinal neurons and restore visual function. Following acute damage, Muller glia (MG) re-enter the cell cycle and produce multipotent progenitors whose progeny differentiate into mature neurons. Both MG reprogramming and proliferation of retinal progenitor cells require reactive microglia and associated inflammatory signaling. Paradoxically, MG in zebrafish models of photoreceptor degeneration fail to re-enter the cell cycle and regenerate lost cells. Here, we used the zebrafish cep290 mutant to demonstrate that progressive cone degeneration generates an immune response but does not stimulate MG proliferation. Acute light damage triggered photoreceptor regeneration in cep290 mutants but cones were only restored to pre-lesion densities. Using irf8 mutant zebrafish, we found that the chronic absence of microglia reduced inflammation and rescued cone degeneration in cep290 mutants. Finally, single-cell RNA-sequencing revealed sustained expression of notch3 in MG of cep290 mutants and inhibition of Notch signaling induced MG to re-enter the cell cycle. Our findings provide new insights on the requirements for MG to proliferate and the potential for immunosuppression to prolong photoreceptor survival.

Efficiency of in vitro culture techniques applied to soybean (Glycine max (L.) Merr.) accessions from the VIR collection

Using a wide range of modern biotechnologies and genetic techniques to study plant germplasm accessions held by VIR makes it possible to procure valuable results, required for the development of new high-yielding cultivars adapted to adverse environmental conditions and possessing specified technological properties, particularly to identify and mark new genes and alleles useful for plant breeding. This research trend is in line with Presidential Decree No. 680 “Concerning the development of genetic technologies in the Russian Federation”. Soybean is among the key crops in agricultural production, but the use of next-generation breeding tools to obtain new soybean cultivars with desired properties is still limited. Successful application of novel methods also requires new approaches to studying soybean accessions, specifically their ability to regenerate and produce calluses for subsequent inclusion in biotechnological programs.Ten soybean accessions of various origin, contrasting in ripening schedules, were selected to study the possibility of effective introduction into in vitro culture and further assessment of their ability to produce calluses and regenerate in in vitro culture. The work included evaluating the effects of different seed sterilization techniques (one-step sterilization, using a commercial bleach, and two-step one, combining the impacts of a chlorine-containing preparation and hydrogen peroxide), types of explants (epicotyls, hypocotyls, cotyledon nodes, and cotyledon leaf segments), and phytohormone composition of nutrient medium: (1) MS + 1.13 mg/L BAP + 0.5 mg/L HA, and (2) MS +1 mg/L BAP + 0.1 mg/L IAA).The assessment results showed that the option of two-step seed sterilization was the most effective for soybean at the stage of in vitro culture initiation, while hypocotyls, epicotyls, and cotyledon nodes had the highest callus formation ability in both types of nutrient media.

Nanopolymers: powerful tools in neuroprotection and neuroregeneration

: Disorders of the central and peripheral nervous systems are still major human health issues. Researchers have been seeking ways to boost neuroregeneration and neuroprotection since ancient times in order to overcome the brain's, spinal cord's, and peripheral nerves' limited ability to regenerate spontaneously.In this scenario, nanopolymers have shown great potential in terms of drug delivery systems and scaffolds, diminishing the scale of tissue damage and promoting functional recovery in both acute and chronic injuries. A diversity of natural and synthetic polymers has been exploited due to the unique characteristics of these polymers regarding their mechanical and biological properties. These properties dictate how the biomaterial interact with biological systems and how they are distinct in each polymer. This makes them suitable for numerous applications that range from the controlled release of an anti-inflammatory drug to axonal guidance. The versatility of nanopolymers makes them a rich source for therapeutic approaches in the neuroscience field, especially in neuroprotection and neuroregeneration.

Regenerative Polarity of the Fin Ray in Zebrafish Caudal Fin and Related Tissue Formation on the Cut Surface

Zebrafish caudal fin rays are used as a model system for regeneration because of their high regenerative ability, but studies on the regeneration polarity of the fin ray are limited. To investigate this regeneration polarity, we made a hole to excise part of the fin ray and analyzed the regeneration process. We confirmed that the fin rays always regenerated from the proximal margin toward the distal margin, as previously reported; however, regeneration-related genes were expressed at both the proximal and distal edges of the hole in the early stage of regeneration, suggesting that the regenerative response also occurs at the distal edge. One difference between the proximal and distal margins is a sheet-like tissue that is formed on the apical side of the regenerated tissue at the proximal margin. This sheet-like tissue was not observed at the distal edge. To investigate whether the distal margin was also capable of forming this sheet-like tissue and subsequent regeneration, we kept the distal margin separated from the proximal margin by manipulation. Consequently, the sheet-like tissue was formed at the distal margin and regeneration of the fin ray was also induced. The regenerated fin rays from the distal margin protruded laterally from the caudal fin and then bent distally, and their ends showed the same characteristics as those of the normal fin rays. These results suggest that fin rays have an ability to regenerate in both directions; however, under normal conditions, regeneration is restricted to the proximal margin because the sheet-like tissue is preferentially formed on the apical side of the regenerating tissue from the proximal margin.

Protease Activated Receptor 1 and Its Ligands as Main Regulators of the Regeneration of Peripheral Nerves

In contrast with the brain and spinal cord, peripheral nerves possess a striking ability to regenerate after damage. This characteristic of the peripheral nervous system is mainly due to a specific population of glial cells, the Schwann cells. Schwann cells promptly activate after nerve injury, dedifferentiate assuming a repair phenotype, and assist axon regrowth. In general, tissue injury determines the release of a variety of proteases which, in parallel with the degradation of their specific targets, also activate plasma membrane receptors known as protease-activated receptors (PARs). PAR1, the prototypical member of the PAR family, is also known as thrombin receptor and is present at the Schwann cell plasma membrane. This receptor is emerging as a possible regulator of the pro-regenerative capacity of Schwann cells. Here, we summarize the most recent literature data describing the possible contribution of PAR1 and PAR1-activating proteases in regulating the regeneration of peripheral nerves.

Two-Dimensional Nanomaterials for Peripheral Nerve Engineering: Recent Advances and Potential Mechanisms

Peripheral nerve tissues possess the ability to regenerate within artificial nerve scaffolds, however, despite the advance of biomaterials that support nerve regeneration, the functional nerve recovery remains unsatisfactory. Importantly, the incorporation of two-dimensional nanomaterials has shown to significantly improve the therapeutic effect of conventional nerve scaffolds. In this review, we examine whether two-dimensional nanomaterials facilitate angiogenesis and thereby promote peripheral nerve regeneration. First, we summarize the major events occurring after peripheral nerve injury. Second, we discuss that the application of two-dimensional nanomaterials for peripheral nerve regeneration strategies by facilitating the formation of new vessels. Then, we analyze the mechanism that the newly-formed capillaries directionally and metabolically support neuronal regeneration. Finally, we prospect that the two-dimensional nanomaterials should be a potential solution to long range peripheral nerve defect. To further enhance the therapeutic effects of two-dimensional nanomaterial, strategies which help remedy the energy deficiency after peripheral nerve injury could be a viable solution.

The Role of Satellite Cells in Skeletal Muscle Regeneration—The Effect of Exercise and Age

The population of satellite cells (mSCs) is highly diversified. The cells comprising it differ in their ability to regenerate their own population and differentiate, as well as in the properties they exhibit. The heterogeneity of this group of cells is evidenced by multiple differentiating markers that enable their recognition, classification, labeling, and characterization. One of the main tasks of satellite cells is skeletal muscle regeneration. Myofibers are often damaged during vigorous exercise in people who participate in sports activities. The number of satellite cells and the speed of the regeneration processes that depend on them affect the time structure of an athlete’s training. This process depends on inflammatory cells. The multitude of reactions and pathways that occur during the regeneration process results in the participation and control of many factors that are activated and secreted during muscle fiber damage and at different stages of its regeneration. However, not all of them are well understood yet. This paper presents the current state of knowledge on satellite cell-dependent skeletal muscle regeneration. Studies describing the effects of various forms of exercise and age on this process were reviewed.