Lizard Tail Research Articles

Observations on FGF immunoreactivity in the regenerating tail blastema, and in the limb and tail scars of lizard suggest that FGFs are required for regeneration

Tail regeneration in lizards depends on the stimulation of growth factors, including Fibroblast Growth Factors (FGFs). Light and ultrastructural immunolocalization of FGFs was compared between the rege-nerating tail blastema and the limb where no regeneration occurs. A likely epithelial-mesenchymal transition occurs following amputation in both tail and limb and FGFs are present in the wound epidermis of both organs at 7-14 days post-amputation, and at lower intensity in mesenchymal cells of the blastema. Immunoreactivity for FGFs disappears in the limb wound epidermis after 14 days post-amputation and in the epithelium covering tails induced to form scars, whereas it remains in the apical tail epithelium. These observations suggest that scarring in the limb or the induced scarring in the tail correlate with the disappearance of FGFs. Basic FGF is concen-trated in the incomplete basement membrane between the epidermis and the tail blastema where the essential signaling process that allows the continuous growth of the regenerative blastema may occur. The study suggests that the successful regeneration of lizard tail is dependent on the presence of FGFs in the wound epidermis, which are probably released into the blastema.

Adaptive tails? Parallel evolution of expanded tails in monsoonal tropics lineages of an Australian gecko radiation (Oedura)

Abstract Ecological drivers of variation in the morphology of the lizard tail are understudied despite its important and varied functions in defence, locomotion, balance, climbing, and resource storage. We quantified variation in original tail shape and surface area-to-volume ratio (SA : V) in an Australian gecko clade (Oedura) and tested whether environmental variables are predictors of this variation. To use museum specimens, we developed an approach to straighten deformed preserved tails for accurate shape analysis. Tail shape varied from a relatively ‘typical lizard’ tail—long, tapered, and circular in cross-section—to a distinctive expanded, wide, and flat shape. Extreme versions of the latter shape seem to have evolved in parallel in two distantly related lineages. Wide tails and low SA : V ratio values occur in the Australian Monsoonal Tropics, while arid zone species all had a narrow, tapered tail with high SA : V. These data suggest expanded or bulbous tails may be analogous to succulence in plants and an adaptation for resource storage in environments with predictable peaks (wet season) and dearths (dry season) of resource availability. However, limited replicated evolution of bulbous tails precludes statistical significance in this case, and more analyses of tail anatomy in Oedura and other lizard clades are required to test this hypothesis further.

Immunolocalization of lix1 in the regenerating tail of lizard indicates that the protein is mainly present in the nervous tissue

PurposeLizard regeneration derives from the re-activation of a number of developmental genes after tail amputation. Among genes with the highest expression, as indicated from the transcriptome, is lix1 which functional role is not known. MethodAn antibody that cross-reacts with the lizard Podarcis muralis lix1 has been utilized to detect by immunofluorescence the sites of localization of the protein in the regenerating tail. ResultsLix1-protein is almost exclusively localized in the regenerating spinal cord (ependyma) and nerves growing into the blastema, in sparse blastema cells but is undetectable in other tissues. ConclusionsSince the spinal cord is essential to stimulate tail regeneration it is hypothesized that the lix1 protein is part of the signaling or growing factors produced from the regenerating spinal cord that are needed for tail regeneration of the lizard tail.

Single-cell analysis of lizard blastema fibroblasts reveals phagocyte-dependent activation of Hedgehog-responsive chondrogenesis

Lizards cannot naturally regenerate limbs but are the closest known relatives of mammals capable of epimorphic tail regrowth. However, the mechanisms regulating lizard blastema formation and chondrogenesis remain unclear. Here, single-cell RNA sequencing analysis of regenerating lizard tails identifies fibroblast and phagocyte populations linked to cartilage formation. Pseudotime trajectory analyses suggest spp1+-activated fibroblasts as blastema cell sources, with subsets exhibiting sulf1 expression and chondrogenic potential. Tail blastema, but not limb, fibroblasts express sulf1 and form cartilage under Hedgehog signaling regulation. Depletion of phagocytes inhibits blastema formation, but treatment with pericytic phagocyte-conditioned media rescues blastema chondrogenesis and cartilage formation in amputated limbs. The results indicate a hierarchy of phagocyte-induced fibroblast gene activations during lizard blastema formation, culminating in sulf1+ pro-chondrogenic populations singularly responsive to Hedgehog signaling. These properties distinguish lizard blastema cells from homeostatic and injury-stimulated fibroblasts and indicate potential actionable targets for inducing regeneration in other species, including humans.

Effectivity of Shark Cartilage (Carcharhinus sorrah) Ointment Extract on Growth of Lizard (Mabouya multifasciata kuhl) Regenerated Tail

Shark (Carcharhinus sorrah) is a fish whose entire endoskeleton is composed of cartilage. Fish cartilage is widely used for treatment because shark cartilage (SC) contains glucosamine (GS) and chondroitin sulfate (CS) compounds. This study aims to determine the benefits of glucosamine and chondroitin sulfate derived from SC extract on lizard tail regeneration. The study was initiated by testing the characteristics of the SC extract ointment which included tests of spreadability, pH, viscosity and adhesion of the ointment. The effectiveness test of SC extract ointment was done using 36 lizards that were autotomized and divided into 4 treatment groups. The treatment in the form of SC extract ointment with concentrations of 0% (control), 5%, 10%, and 15% was applied to the autotomized tail every morning and evening. The lizards were then kept for 7; 18; and 35 days. The test data for the physicochemical character of the SC extract ointment were analyzed using one-way ANOVA with a significance level of 5% (p<0.05) and the lizard regeneration tail length data were analyzed using a two-way ANOVA with a significance level of 5%. (p<0.05). The result of the research showed that there was a significant difference in the physicochemical character of the spread of SC extract ointment, meanwhile the other physicochemical characters showed no significant difference. The SC extract ointment used in this study was not effective in the growth of lizard regenerate tails.

Protein extracts from regenerating lizard tail show an inhibitory effect on human cancer cells cultivated in-vitro

Backgroundaccumulating evidence indicates that during tail regeneration in lizards the initial stage of regenerative blastema is a tumor-like proliferative outgrowth that rapidly elongates into a new tail composed of fully differentiated tissues. Both oncogenes and tumor-suppressors are expressed during regeneration, and it has been hypothesized that an efficient control of cell proliferation avoids that the blastema is turned into a tumor outgrowth. Methodsin order to determine whether functional tumor-suppressors are present in the growing blastema we have utilized protein extracts collected from early regenerating tails of 3–5 mm that have been tested for a potential anti-tumor effect on in-vitro culture by using cancer cell lines from human mammary gland (MDA-MB-231) and prostate cancer (DU145). Resultsat specific dilutions, the extract determines a reduction of viability in cancer cells after 2–4 days of culture, as supported by statistical and morphological analyses. While control cells appear viable, treated cells result damaged and produce an intense cytoplasmic granulation and degeneration. Conclusionsthis negative effect on cell viability and proliferation is absent using tissues from the original tail supporting the hypothesis that only regenerating tissues synthesize tumor-suppressor molecules. The study suggests that the regenerating tail of lizard at the stages here selected contains some molecules that determine inhibition of cell viability on the cancer cells analyzed.

Neurogenesis in the regenerating tail of tsinling dwarf skinks (Scincella tsinlingensis)

AbstractSpinal ganglia and peripheral nerves innervate the regenerating tail and muscles of lizards, which provide new opportunities to probe the mechanisms leading to successful functional recovery following spinal cord injury. The regenerated spinal cord and peripheral nerves were detected using immunohistochemistry in original and regenerating tails of Scincella tsinlingensis. Our results showed that positive PCNA, GFAP and SOX2 cells were observed in the ependymal ducts at 15 and 30 days after the autotomy (dpa), with a small number of immunopositive NSE neurons. GFAP and SOX2 positive cells were primarily localized along the regenerated spinal cord after 45 dpa, and the descending nerve of medulla tissue showed positive NSE. Peripheral axons distributed around the muscle and inside the connective tissue and muscle tissue at 15 dpa. The number of axons decreased after 30 dpa. The peripheral axons was mainly distributed between the connective tissue, muscle group and the muscle and epidermis, presenting a radial distribution centred on the cartilage tube at 120 dpa. MBP myelination labelling of the regenerated tail at 30 dpa revealed that the regenerated axons rapidly myelinated along the rostro‐caudal axis. The density of NMJ significantly increased at 120 dpa and 250 dpa. In the second regenerated tails, NMJ density at 250 dpa was still greater than original tails. Overall, these results indicated that neurogenesis was an early event and the ependymal cells were heterogeneous in the regenerated spinal cord of S. tsinlingensis. The regenerated peripheral axons presented a radial distribution centred on the cartilage canal, and the regenerated axons were rapidly myelinated along the rostro‐caudal axis. During the process of regeneration, there were a large number of regenerated neuromuscular joints with high density.

Optimal root oxygen release from two macrophytes Saururus cernuus L. and Pistia stratiotes L. varies with light and temperature in simulated constructed wetlands microcosms

Different environmental factors influence photosynthesis, transpiration, stomatal conductance, and oxygen released from macrophytes' roots. We measured several physiological parameters of Saururus cernuus L. (Lizard's Tail) and Pistia stratiotes L. (Water Cabbage) by exposing the plants to various controlled environmental conditions. The oxygen released from the plant roots was also used to treat the chemical and biological oxygen demand in wastewater in microcosms. This work determined that photosynthetic rate and oxygen release were dependent not only on the plant species but also on the light intensity exposed. The highest rate of photosynthesis differed considerably between the two plants, as S. cernuus required more light intensity than P. stratiotes. Maximum root oxygen release was at peak photosynthesis, thus correlated with light intensity. The temperature had an effect on stomatal conductance, photosynthesis rate, and transpiration rate was affected by the wind speed. For the highest stomatal conductance and photosynthesis, P. stratiotes required a higher temperature than S. cernuus. Stomatal conductance also influenced the oxygen released from plant roots. Furthermore, a relationship was determined between physiological processes and their potential to release oxygen from the roots where the reduction in COD and BOD measured at the end of the experiment was largely attributed to the oxygen that the macrophytes added to the substrate through their roots. The results of this study provide a good benchmark for plant scientists to predict the physiological processes of plants in response to different environmental conditions to control the negative impacts of harsh environmental conditions on plants' ability to release oxygen in their rhizosphere and to improve the efficiency of CW.

Immunolocalization of CD3, CD5 and MHCII in amputated tail and limb of the lizard Podarcis muralis marks a scarring healing program

AbstractThe effect of inflammation on tail and limb amputation in lizards is believed to inhibit regeneration. In support of previous studies, the present experimental and immunohistochemical analysis has detected some markers (CD3, CD5, MHCII) of mammalian T‐lymphocytes and macrophages of inflammatory type in three different conditions where inflammation is activated. Bioinformatics comparisons indicate that the employed antibodies cross‐react with lizard cells. While in regenerating tails few or no immune cells are seen, in microbial‐infected and non‐regenerating tails, a massive infiltration of mast cells, sparse macrophages and T‐lymphocytes is present. In healing limbs, immunolabelled cells likely represented by macrophages and lymphocytes remain in healing tissues of the stump for 2–3 weeks. In the regenerating blastema after heat cauterization of the apical region, a massive infiltration of mast cells and granulocytes occurs at 1–3 days post‐injury and a scarring outgrowth is later formed. Although the three markers appear not discriminate the types of immune‐cells in lizard, they confirms that immunolabelled cells expressing markers of inflammation are produced in large number in the tail or limbs with strong inflammatory condition. Coupled with previous studies, the present observations support the idea that a high inflammation attracting numerous mast‐cells, inflammatory macrophages and T‐lymphocyte inhibits regeneration.

The regenerating tail of lizard transits through a tumour‐like stage represented by the regenerative blastema

AbstractReview. The regenerating tail of lizard transits through a tumour‐like stage represented by the regenerative blastema. Acta Zoologica (Stockolm). Molecular studies on lizard tail regeneration indicate that the blastema stage is a tumour‐like outgrowth capable of self‐regulate to produce a new tail. Various oncogenes and tumour suppressors are expressed, and their proteins are localized in specific regions of the growing blastema. SnoRNAs are exclusively overexpressed in the tail blastema suggesting changes in ribosome translation efficiency in blastema cells, like in cancer. Blastema cells secrete high levels of hyaluronate and adopt an anaerobic metabolism (Warburg effect). These studies indicate that the lizard blastema represents a unique case among terrestrial vertebrates of physiological tumour remission. Mesenchymal cells and fibroblasts forming the blastema are turned within 1–2 months into a functional organ, the tail. In vitro studies on isolated mesenchymal cells from the regenerative blastema shows that these cells do not undergo contact inhibition but continue proliferation after confluence, and contain nestin, vimentin and K17. After 2–3 weeks they stratify into 5–7 layers forming a pellicle of loose connective tissue. Future molecular studies on genes and proteins that allow the control of growth in the lizard blastema may help to determine how lizards turn a tumour into a new organ with numerous differentiated and functional tissues, providing clues on cancer growth regulation.

The Mystery of the Lizard Tail

Quick breakage of lizard tails to escape predation has remained a mystery for centuries. Our study explains the balance between firm attachment and the quick release of the tail and highlights the lizard's way of achieving the “just right” connection for its best chance of survival.

Pengukuran Awal Hemipenis Sauria Lamprolepis Smaragdina (Scincidae) dan Lophosaurus Dilophus (Agamidae)

The characteristics of the hemipenis Scincidae and Agamidae New Guinea are veryrarely studied, although they are very easy to do. Morphological characteristics andhemipenis size between these two families are very different. Some have a cylindrical hemipenis that is not lobed to lobed, and some even have a variety of structures withdistinctive ornaments. Tail length can affect the length of the hemipenis. This study aims to describe the characteristics of the hemipenis Scincidae and Agamidae New Guinea. The species Lamprolepis smaragdina and Hypsilurus dilophus were sampledto represent other species in these two families. Preservation of lizard hemipenis refersto research by Zaher and Prudente (2003), Dowling and Savage (1960). Comparison of hemipenis morphology of the two species is very different based on the structure and shape. Hemipenis L. smaragdina is cylindrical and not lobed. The surface structure ofthe hemipenis is smooth and there is no distinctive ornament. While H. dilophus has a cylindrical hemipenis not lobulated with a larger size. The structure is rough, wavy and wider. The results of sample measurements in this study have also become strong evidence that the length of the lizard's tail can affect the length of the hemipenis.

De Novo Transcriptome Sequencing and Analysis of Differential Gene Expression among Various Stages of Tail Regeneration in Hemidactylus flaviviridis.

Across the animal kingdom, lizards are the only amniotes capable of regenerating their lost tail through epimorphosis. Of the many reptiles, the northern house gecko, Hemidactylus flaviviridis, is an excellent model system that is used for understanding the mechanism of epimorphic regeneration. A stage-specific transcriptome profile was generated in the current study following an autotomized tail with the HiSeq2500 platform. The reads obtained from de novo sequencing were filtered and high-quality reads were considered for gene ontology (GO) annotation and pathway analysis. Millions of reads were recorded for each stage upon de novo assembly. Up and down-regulated transcripts were categorized for early blastema (EBL), blastema (BL) and differentiation (DF) stages compared to the normal tail (NT) by differential gene expression analysis. The transcripts from developmentally significant pathways such as FGF, Wnt, Shh and TGF-β/BMP were present during tail regeneration. Additionally, differential expression of transcripts was recorded from biological processes, namely inflammation, cell proliferation, apoptosis and cell migration. Overall, the study reveals the stage-wise transcriptome analysis in conjunction with cellular processes as well as molecular signaling pathways during lizard tail regeneration. The knowledge obtained from the data can be extrapolated to configure regenerative responses in other amniotes, including humans, upon loss of a complex organ.

Endoplasmin regulates differentiation of tonsil-derived mesenchymal stem cells into chondrocytes through ERK signaling

It is well-known that some species of lizard have an exceptional ability known as caudal autotomy (voluntary self-amputation of the tail) as an anti-predation mechanism. After amputation occurs, they can regenerate their new tails in a few days. The new tail section is generally shorter than the original one and is composed of cartilage rather than vertebrae bone. In addition, the skin of the regenerated tail distinctly differs from its original appearance. We performed a proteomics analysis for extracts derived from regenerating lizard tail tissues after amputation and found that endoplasmin (ENPL) was the main factor among proteins up-regulated in expression during regeneration. Thus, we performed further experiments to determine whether ENPL could induce chondrogenesis of tonsil-derived mesenchymal stem cells (T-MSCs). In this study, we found that chondrogenic differentiation was associated with an increase of ENPL expression by ER stress. We also found that ENPL was involved in chondrogenic differentiation of T-MSCs by suppressing extracellular signal-regulated kinase (ERK) phosphorylation.

Biomimicking interfacial fracture behavior of lizard tail autotomy with soft microinterlocking structures

Biological soft interfaces often exhibit complex microscale interlocking geometries to ensure sturdy and flexible connections. If needed, the interlocking can rapidly be released on demand leading to an abrupt decrease of interfacial adhesion. Here, inspired by lizard tail autotomy where such apparently tunable interfacial fracture behavior can be observed, we hypothesized an interlocking mechanism between the tail and body based on the muscle-actuated mushroom-shaped microinterlocks along the fracture planes. To mimic the fracture behavior of the lizard tail, we developed a soft bilayer patch that consisted of a dense array of soft hemispherical microstructures in the upper layer acting as mechanical interlocks with the counter body part. The bottom control layer contained a microchannel that allowed to deflect the upper layer when applying the negative pressure, thus mimicking muscle contraction. In the microinterlocked condition, the biomimetic tail demonstrated a 2.7-fold and a three-fold increase in adhesion strength and toughness, respectively, compared to the pneumatically released microinterlocks. Furthermore, as per the computational analysis, the subsurface microchannel in the control layer enabled augmented adhesion by rendering the interface more compliant as a dissipative matrix, decreasing contact opening and strain energy dissipation by 50%. The contrasting features between the microinterlocked and released cases demonstrated a highly tunable adhesion of our biomimetic soft patch. The potential applications of our study are expected in soft robotics and prosthetics.

Immunolocalization of adenomatous polyposis coli protein (apc) in the regenerating lizard tail suggests involvement in tissue differentiation and regulation of growth

Lizard tail regeneration is likely regulated by the balanced activity of oncogenes and tumor suppressors that control cell proliferation avoiding tumorigenic degeneration. One of the main tumor suppressor genes present in the regenerating tail is the "adenomatous polyposis coli (apc)" but the localization of its coded protein (apc) is not known. This protein may be involved in regulation of apical-basal tail regeneration in lizards. The present immunohistochemical study shows that apc is localized in apical wound epidermis and regenerating ependyme, two tissues that proliferate and also express onco-genes. Apc is not present in blastema cells but localizes in differentiating cells of regenerating scales, muscles and less intensely in the non-apical ependymal epithelium and cartilage. This suggests that apc is involved in the induction of their differentiation. The apc immunolabeling is mainly nuclear in the basal epidermal layer of the apical wound epidermis where it may be involved in modulating keratinocytes proliferation, like in the forming scales. In regenerating muscle and cartilage apc is mainly cytoplasmic while sparse labeled nuclei are seen in proliferative areas of these tissues. In the regenerating spinal cord, the nuclear and cytoplasmic apc labeling is present in ependymal cells of the distal-most ependymal ampulla but the labeling fades in more proximal regions and mainly remains in the cytoplasm facing the central canal and in sparse nuclei. It is suggested that the pattern of immunolabeling for apc indicates that this tumor suppressor may contribute to tissue differentiation within the regenerating tail.

08. Red tail in male spiny footed lizards Acanthodactylus erythrurus during the breeding season

08. Red tail in male spiny footed lizards Acanthodactylus erythrurus during the breeding season

Red tail in male spiny footed lizards Acanthodactylus erythrurus during the breeding season

Red tail in male spiny footed lizards Acanthodactylus erythrurus during the breeding season

Biomimetic fracture model of lizard tail autotomy.

Lizard tail autotomy is an antipredator strategy consisting of sturdy attachment at regular times but quick detachment during need. We propose a biomimetic fracture model of lizard tail autotomy using multiscale hierarchical structures. The structures consist of uniformly distributed micropillars with nanoporous tops, which recapitulate the high-density mushroom-shaped microstructures found on the lizard tail's muscle fracture plane. The biomimetic experiments showed adhesion enhancement when combining nanoporous interfacial surfaces with flexible micropillars in tensile and peel modes. The fracture modeling identified micro- and nanostructure-based toughening mechanisms as the critical factor. Under wet conditions, capillarity-assisted energy dissipation pertaining to liquid-filled microgaps and nanopores further increased the adhesion performance. This research presents insights on lizard tail autotomy and provides new biomimetic ideas to solve adhesion problems.

Lizard Blastema Organoid Model Recapitulates Regenerated Tail Chondrogenesis.

(1) Background: Lizard tail regeneration provides a unique model of blastema-based tissue regeneration for large-scale appendage replacement in amniotes. Green anole lizard (Anolis carolinensis) blastemas contain fibroblastic connective tissue cells (FCTCs), which respond to hedgehog signaling to create cartilage in vivo. However, an in vitro model of the blastema has not previously been achieved in culture. (2) Methods: By testing two adapted tissue dissociation protocols and two optimized media formulations, lizard tail FCTCs were pelleted in vitro and grown in a micromass blastema organoid culture. Pellets were analyzed by histology and in situ hybridization for FCTC and cartilage markers alongside staged original and regenerating lizard tails. (3) Results: Using an optimized serum-free media and a trypsin- and collagenase II-based dissociation protocol, micromass blastema organoids were formed. Organoid cultures expressed FCTC marker CDH11 and produced cartilage in response to hedgehog signaling in vitro, mimicking in vivo blastema and tail regeneration. (4) Conclusions: Lizard tail blastema regeneration can be modeled in vitro using micromass organoid culture, recapitulating in vivo FCTC marker expression patterns and chondrogenic potential.