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ELife Jul 2023Analysis of specimens preserved in amber from the Cretaceous period suggests that nematodes changed their host preference towards insects with a complete metamorphosis...
Analysis of specimens preserved in amber from the Cretaceous period suggests that nematodes changed their host preference towards insects with a complete metamorphosis more recently.
Topics: Animals; Fossils; Insecta; Nematoda; Amber; Metamorphosis, Biological
PubMed: 37449733
DOI: 10.7554/eLife.90008 -
WIREs Mechanisms of Disease Jan 2021
Topics: Humans; Metamorphosis, Biological
PubMed: 33369203
DOI: 10.1002/wsbm.1517 -
Family Medicine May 2021
Topics: Humans; Metamorphosis, Biological
PubMed: 34019689
DOI: 10.22454/FamMed.2021.149656 -
Philosophical Transactions of the Royal... Oct 2019Metamorphosis and, in particular, holometaboly, the development of organisms through a series of discrete stages (egg, larva, pupa, adult) that hardly resemble one... (Review)
Review
Metamorphosis and, in particular, holometaboly, the development of organisms through a series of discrete stages (egg, larva, pupa, adult) that hardly resemble one another but are finely adapted to specific roles in the life cycle of the organism, has fascinated and mystified humans throughout history. However, it can be difficult to visualize the dramatic changes that occur during holometaboly without destructive sampling, traditionally through histology. However, advances in imaging technologies developed mainly for medical sciences have been applied to studies of insect metamorphosis over the past couple of decades. These include micro-computed tomography, magnetic resonance imaging and optical coherence tomography. A major advantage of these techniques is that they are rapid and non-destructive, enabling virtual dissection of an organism in any plane by anyone who has access to the image files and the necessary software. They can also be applied in some cases to visualize metamorphosis in vivo, including the periods of most rapid and dramatic morphological change. This review focusses on visualizing the intra-puparial holometabolous metamorphosis of cyclorraphous flies (Diptera), including the primary model organism for all genetic investigations, Drosophila melanogaster, and the blow flies of medical, veterinary and forensic importance, but also discusses similar studies on other insect orders. This article is part of the theme issue 'The evolution of complete metamorphosis'.
Topics: Animals; Diagnostic Imaging; Diptera; Drosophila melanogaster; Insecta; Larva; Metamorphosis, Biological; Pupa
PubMed: 31438819
DOI: 10.1098/rstb.2019.0071 -
Philosophical Transactions of the Royal... Oct 2019The majority of described hexapod species are holometabolous insects, undergoing an extreme form of metamorphosis with an intercalated pupal stage between the larva and... (Review)
Review
The majority of described hexapod species are holometabolous insects, undergoing an extreme form of metamorphosis with an intercalated pupal stage between the larva and adult, in which organs and tissues are extensively remodelled and in some cases completely rebuilt. Here, we review how and why this developmental strategy has evolved. While there are many theories explaining the evolution of metamorphosis, many of which fit under the hypothesis of decoupling of life stages, there are few clear adaptive hypotheses on why complete metamorphosis evolved. We propose that the main adaptive benefit of complete metamorphosis is decoupling between growth and differentiation. This facilitates the exploitation of ephemeral resources and enhances the probability of the metamorphic transition escaping developmental size thresholds. The evolution of complete metamorphosis comes at the cost of exposure to predators, parasites and pathogens during pupal life and requires specific adaptations of the immune system at this time. Moreover, metamorphosis poses a challenge for the maintenance of symbionts and the gut microbiota, although it may also offer the benefit of allowing an extensive change in microbiota between the larval and adult stages. The regulation of metamorphosis by two main players, ecdysone and juvenile hormone, and the related signalling cascades are now relatively well understood. The mechanics of metamorphosis have recently been studied in detail because of the advent of micro-CT and research into the role of cell death in remodelling tissues and organs. We support the argument that the adult stage must necessarily have preceded the larval form of the insect. We do not resolve the still contentious question of whether the larva of insects in general originated through the modification of existing preadult forms or through heterochrony as a modified embryonic stage (pronymph), nor whether the holometabolous pupa arose as a modified hemimetabolous final stage larva. This article is part of the theme issue 'The evolution of complete metamorphosis'.
Topics: Animals; Biological Evolution; Insecta; Metamorphosis, Biological
PubMed: 31438816
DOI: 10.1098/rstb.2019.0063 -
Developmental Dynamics : An Official... Jun 2021Amphibians display very diverse life cycles and development can be direct, where it occurs in ovo and a juvenile hatches directly, or biphasic, where an aquatic larva...
Amphibians display very diverse life cycles and development can be direct, where it occurs in ovo and a juvenile hatches directly, or biphasic, where an aquatic larva hatches and later undergoes metamorphosis followed by sexual maturation. In both cases, metamorphosis, corresponds to the post embryonic transition (PETr). A third strategy, only found in Urodeles, is more complex as larvae reach sexual maturity before metamorphosis, which can become accessory. The resulting paedomorphs retain their larval characters and keep their aquatic habitat. Does it mean that paedomorphs do not undergo PETr? Recent work using high throughput technologies coupled to system biology and developmental endocrinology revisited this question and provided novel datasets indicating that a paedomorph's "larval" tissue undergoes a proper developmental transition. Together with historical data, we propose that this transition is a marker of the PETr, which would be distinct from metamorphosis. This implies that (a) complex life cycles would result from the uncoupling of PETr and metamorphosis, and (b) biphasic life cycles would be a special cases where they occur simultaneously.
Topics: Amphibians; Animals; Larva; Life Cycle Stages; Metamorphosis, Biological
PubMed: 33527613
DOI: 10.1002/dvdy.304 -
Development (Cambridge, England) Mar 2020Understanding how to promote organ and appendage regeneration is a key goal of regenerative medicine. The frog, , can achieve both scar-free healing and tissue... (Review)
Review
Understanding how to promote organ and appendage regeneration is a key goal of regenerative medicine. The frog, , can achieve both scar-free healing and tissue regeneration during its larval stages, although it predominantly loses these abilities during metamorphosis and adulthood. This transient regenerative capacity, alongside their close evolutionary relationship with humans, makes an attractive model to uncover the mechanisms underlying functional regeneration. Here, we present an overview of as a key model organism for regeneration research and highlight how studies of have led to new insights into the mechanisms governing regeneration.
Topics: Animals; Humans; Larva; Metamorphosis, Biological; Models, Biological; Regeneration; Spinal Cord Injuries; Xenopus laevis
PubMed: 32193208
DOI: 10.1242/dev.180844 -
Philosophical Transactions of the Royal... Jul 2023Amphibians are at the forefront of bridging the evolutionary gap between mammals and more ancient, jawed vertebrates. Currently, several diseases have targeted... (Review)
Review
Amphibians are at the forefront of bridging the evolutionary gap between mammals and more ancient, jawed vertebrates. Currently, several diseases have targeted amphibians and understanding their immune system has importance beyond their use as a research model. The immune system of the African clawed frog, , and that of mammals is well conserved. We know that several features of the adaptive and innate immune system are very similar for both, including the existence of B cells, T cells and innate-like T cells. In particular, the study of the immune system at early stages of development is benefitted by studying tadpoles. The tadpoles mainly rely on innate immune mechanisms including pre-set or innate-like T cells until after metamorphosis. In this review we lay out what is known about the innate and adaptive immune system of including the lymphoid organs as well as how other amphibian immune systems are similar or different. Furthermore, we will describe how the amphibian immune system responds to some viral, bacterial and fungal insults. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
Topics: Animals; Immune System; Biological Evolution; Metamorphosis, Biological; Xenopus laevis; Mammals
PubMed: 37305914
DOI: 10.1098/rstb.2022.0123 -
Annual Review of Microbiology Sep 2020The swimming larvae of many marine animals identify a location on the seafloor to settle and undergo metamorphosis based on the presence of specific surface-bound... (Review)
Review
The swimming larvae of many marine animals identify a location on the seafloor to settle and undergo metamorphosis based on the presence of specific surface-bound bacteria. While bacteria-stimulated metamorphosis underpins processes such as the fouling of ship hulls, animal development in aquaculture, and the recruitment of new animals to coral reef ecosystems, little is known about the mechanisms governing this microbe-animal interaction. Here we review what is known and what we hope to learn about how bacteria and the factors they produce stimulate animal metamorphosis. With a few emerging model systems, including the tubeworm , corals, and the hydrozoan , we have begun to identify bacterial cues that stimulate animal metamorphosis and test hypotheses addressing their mechanisms of action. By understanding the mechanisms by which bacteria promote animal metamorphosis, we begin to illustrate how, and explore why, the developmental decision of metamorphosis relies on cues from environmental bacteria.
Topics: Animals; Anthozoa; Aquatic Organisms; Bacteria; Coral Reefs; Ecosystem; Host Microbial Interactions; Larva; Metamorphosis, Biological; Polychaeta
PubMed: 32905754
DOI: 10.1146/annurev-micro-011320-012753 -
Natural Product Reports Sep 2022Covering: findings from early 1980s until early 2022Microbial-derived cues of marine biofilms induce settlement and metamorphosis of marine organisms, a process... (Review)
Review
Covering: findings from early 1980s until early 2022Microbial-derived cues of marine biofilms induce settlement and metamorphosis of marine organisms, a process responsible for the emergence of diverse flora and fauna in marine habitats. Although this phenomenon is known for more than 80 years, the research field has only recently gained much momentum. Here, we summarize the currently existing biochemical and microbial knowledge about microbial signalling molecules, con-specific signals, and synthetic compounds that induce or prevent recruitment, settlement, and metamorphosis in invertebrate larvae. We discuss the possible modes of action and conclude with perspectives for future research directions in the field of marine chemical ecology.
Topics: Animals; Aquatic Organisms; Biofilms; Larva; Marine Biology; Metamorphosis, Biological
PubMed: 35822257
DOI: 10.1039/d1np00073j