The molecular mechanisms underlying the regeneration process in the earthworm, Perionyx excavatus exhibit indications of apoptosis-induced compensatory proliferation (AICP).

Regeneration is a multifaceted biological phenomenon that necessitates the intricate orchestration of apoptosis, stem cells, and immune responses, culminating in the regulation of apoptosis-induced compensatory proliferation (AICP). The AICP context of research is observed in many animal models like in Hydra, Xenopus, newt, Drosophila, and mouse but so far not reported in earthworm. The earthworm Perionyx excavatus is used in the present study to understand the relationship between AICP-related protein expression and regeneration success in different conditions (normal regeneration and abnormal multiple bud formation). Initially, the worms are amputated into five equal portions and it is revealed that regeneration in P. excavatus is clitellum independent and it gives more preference for anterior regeneration (regrowth of head portion) than for posterior regeneration (regrowth of tail portion). The posterior segments of the worm possess enormous regeneration ability but this is lacking in anterior segments. Alkaline phosphate, a stem cell marker, shows strong signals throughout all the posterior segments but it decreases in the initial 1st to 15th anterior segments which lack the regeneration ability. While regenerating normally, it was suggested that the worm follow AICP principles. This is because there was increased expression of apoptosis signals throughout the regeneration process along with constant expression of stem cell proliferation response together with cellular proliferation. In amputated posterior segments maintained in vitro, the apoptosis signals were extensively detected on the 1st day. However, on the 4th and 6th days, caspase-3 and H2AX expression are significantly suppressed, which may eventually alter the Wnt3a and histone H3 patterns that impair the AICP and result in multiple bud formation. Our results suggest that AICP-related protein expression pattern is crucial for initiating proper regeneration.

Understanding the Multi-Functional Role of TCTP in the Regeneration Process of Earthworm, Perionyx excavatus.

BACKGROUND: Regeneration is a highly complex process that requires the coordination of numerous molecular events, and identifying the key ruler that governs is important to investigate. While it has been shown that TCTP is a multi-functional protein that regulates cell proliferation, differentiation, apoptosis, anti-apoptosis, stem cell maintenance, and immune responses, but only a few studies associated to regeneration have been reported. To investigate the multi-functional role of TCTP in regeneration, the earthworm Perionyx excavatus was chosen. METHODS: Through pharmacological suppression of TCTP, amputation, histology, molecular docking, and western blotting, the multi-function role of TCTP involved in regeneration is revealed. RESULTS: Amputational studies show that P. excavatus is a clitellum-independent regenerating earthworm resulting in two functional worms upon amputation. Arresting cell cycle at the G1/S boundary using 2 mM Thymidine confirms that P. excavatus execute both epimorphosis and morphallaxis regeneration mode. The pharmacological suppression of TCTP using buclizine results in regeneration suppression. Following the combinatorial injection of 2 mM Thymidine and buclizine, the earthworm regeneration is completely blocked, which suggests a critical functional role of TCTP in morphallaxis. The pharmacological inhibition of TCTP also suppresses the key proteins involved in regeneration: Wnt3a (stem cell marker), PCNA (cell proliferation) and YAP1 (Hippo signalling) but augments the expression of cellular stress protein p53. CONCLUSION: The collective results indicate that TCTP synchronously is involved in the process of stem cell activation, cell proliferation, morphallaxis, and organ development in the regeneration event.

Understanding the process of angiogenesis in regenerating earthworm.

Developing blood vessels from the existing vasculature is vital for the growth of the organism, as well as for systematic wound healing and the repair process. In this study, we investigated the role of angiogenesis during the regeneration process in the earthworm, Eudrilus eugeniae, animal model. Briefly, the morphological examination of blood vessels in juvenile and mature worms is documented, along with the development of new blood vessels in regenerating blastema. However, in vivo and in vitro experiments with juvenile worms revealed that geraniol retards blastemal regeneration growth with undeveloped blood vessels, as compared to the control. The results of qRT-PCR, western blotting, and immunohistochemistry confirmed a reduced expression of VEGFR2 and WNT5A in the day 3 regenerating blastema of geraniol-treated worms, as compared to the control. We conclude that geraniol acts as a potent natural inhibitor of angiogenesis, thereby retarding the regeneration process in earthworms. In addition, for studying angiogenesis and screening effective angiogenesis inhibitors as drug candidates, the earthworm is an ambient animal model system.

Comparative analysis of the survival and regeneration potential of juvenile and matured earthworm, Eudrilus eugeniae, upon in vivo and in vitro maintenance.

Eudrilus eugeniae is a clitellum-dependent earthworm that requires intact clitellum segments for its survival and regeneration. The present study aims to interconnect the survival and regeneration ability that varies between in vivo and in vitro maintenance upon different sites of amputation. The amputated portion of the worm that possesses intact clitellum (13th-18th segments) survived and had the potential to regenerate, whereas worms with partial or without clitellum segments only survived and were unable to regenerate. Besides segment length and clitellum segments, clitellum factors also determined the survival, blastemal initiation and differentiation potential. The survivability and regeneration potential of worms were augmented upon in vitro maintenance. Notably, the amputated segments (1st-10th segments) and posterior segments of similar length, which usually die within the 4th day in vivo, survived for more than 60 days in vitro but lacked the regeneration ability. On the other hand, the amputated posterior segments (30th to 37th segments) from juvenile worms, maintained in in vitro condition, survived and initiated blastema with multiple buds but lacked the ability to regenerate. Interestingly, the equal half of adult worm blastema that is maintained in in vitro conditions were able to form the blastema-like structure with the help of a unique stick. The anterior blastema failed to retain the regenerative structure but the posterior portion of the amputated blastema, which is also associated with a small portion of the body segment, showed the ability to retain the regenerative structure. Our results conclude that the survivability is enhanced upon in vitro maintenance and this condition favours the adult dedifferentiated blastemal and stem cell-enriched juvenile posterior segments to form a regenerative blastema.

Foldscope microscope, an inexpensive alternative tool to conventional microscopy-Applications in research and education: A review.

Microscope is a device used for the visualization of tiny objects which are not visible to the naked eye. Traditional microscopes have been crucial for the advancement of contemporary science and medicine. Recent advancements in the field of microscopy have fueled its exponential growth rate. However, due to their expensive cost and complicated structure, modern microscopes remain inaccessible to the majority of the public. Nonetheless, the foldscope paper microscope has made it possible for anyone to explore and understand the world of microbes and organisms. In this review, we have listed foldscope-based research projects in various domains, as well as their key properties when compared to traditional research microscopes. In addition, we have briefly explored the impact of a foldscope microscope on public health, clinical diagnostics, forensic science, agriculture, basic science, developmental biology, and education. Moreover, the major drawbacks of paper microscopes and the current steps being taken to upgrade foldscope and its features are discussed in this review. Finally, we have concluded with our perspective that the microscope may be updated to imitate the advancement of a conventional microscope. RESEARCH HIGHLIGHTS: The foldscope, a low-cost instrument for studying the microscopic world. Foldscope applications were compared to conventional microscopes in many sectors. The foldscope microscope's existing limitations and potential prospects are highlighted.