The chemical brain hypothesis for the origin of nervous systems

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2021, Volume and Issue: 376(1821), P. 20190761 - 20190761

Published: Feb. 8, 2021

In nervous systems, there are two main modes of transmission for the propagation activity between cells. Synaptic relies on close contact at chemical or electrical synapses while volume is mediated by diffusible signals and does not require direct contact. It possible to wire complex neuronal networks both synaptic transmission. Both types ubiquitous in leading question which appeared first evolution. This paper explores a scenario where chemically organized cellular before evolution, possibility supported presence peptidergic signalling all animals except sponges. Small peptides ideally suited link up cells into networks. They have unlimited diversity, high diffusivity copy numbers derived from repetitive precursors. But diffusion limited becomes inefficient larger bodies. To overcome this, may developed projections formed synaptically connected tiling body surfaces displaying synchronized with pulsatile peptide release. The advent circulatory systems neurohemal organs further reduced constraint imposed diffusion. could contributed explosive radiation stem bilaterians. Neurosecretory centres extant still predominantly wired coexist brain. article part theme issue ‘Basal cognition: multicellularity, neurons cognitive lens’.

Language: Английский

---

Neuropeptide repertoire and 3D anatomy of the ctenophore nervous system

Current Biology, Journal Year: 2021, Volume and Issue: 31(23), P. 5274 - 5285.e6

Published: Sept. 28, 2021

Language: Английский

---

Signaling Pathways That Regulate the Crustacean Molting Gland

Frontiers in Endocrinology, Journal Year: 2021, Volume and Issue: 12

Published: June 21, 2021

A pair of Y-organs (YOs) are the molting glands decapod crustaceans. They synthesize and secrete steroid hormones (ecdysteroids) their activity is controlled by external internal signals. The YO transitions through four physiological states over molt cycle, which mediated molt-inhibiting hormone (MIH; basal state), mechanistic Target Rapamycin Complex 1 (mTORC1; activated Transforming Growth Factor-β (TGFβ)/Activin (committed ecdysteroid (repressed state) signaling pathways. MIH, produced in eyestalk X-organ/sinus gland complex, inhibits synthesis ecdysteroids. model for MIH organized into a cAMP/Ca

Language: Английский

---

Premetazoan Origin of Neuropeptide Signaling

Molecular Biology and Evolution, Journal Year: 2022, Volume and Issue: 39(4)

Published: March 7, 2022

Abstract Neuropeptides are a diverse class of signaling molecules in metazoans. They occur all animals with nervous system and also neuron-less placozoans. However, their origin has remained unclear because no neuropeptide shows deep homology across lineages, none have been found sponges. Here, we identify two precursors, phoenixin (PNX) nesfatin, broad evolutionary conservation. By database searches, sequence alignments, gene-structure comparisons, show that both precursors present bilaterians, cnidarians, ctenophores, We PNX secreted nesfatin precursor homolog the choanoflagellate Salpingoeca rosetta. PNX, particular, is highly conserved, including its cleavage sites, suggesting prohormone processing occurs choanoflagellates. In addition, based on phyletic patterns negative pharmacological assays, question originally proposed GPR-173 (SREB3) as receptor. Our findings revealed homologs derived from longer premetazoan origins thus evolved before neurons.

Language: Английский

---

The Caenorhabditis elegans cuticle and precuticle: a model for studying dynamic apical extracellular matrices in vivo

Genetics, Journal Year: 2024, Volume and Issue: 227(4)

Published: July 12, 2024

Apical extracellular matrices (aECMs) coat the exposed surfaces of animal bodies to shape tissues, influence social interactions, and protect against pathogens other environmental challenges. In nematode Caenorhabditis elegans, collagenous cuticle zona pellucida protein-rich precuticle aECMs alternately external epithelia across molt cycle play many important roles in worm's development, behavior, physiology. Both these types contain matrix proteins related those vertebrates, as well some that are nematode-specific. Extensive differences observed among tissues life stages demonstrate a major feature epithelial cell identity. addition forming discrete layers, components assemble into complex substructures such ridges, furrows, nanoscale pillars. The epidermis mechanically linked, allowing sense damage induce protective innate immune stress responses. C. elegans model, with its optical transparency, facilitates study aECM biology structure/function relationships all myriad ways by which can an organism.

Language: Английский

---

Jellyfish genomes reveal distinct homeobox gene clusters and conservation of small RNA processing

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: June 19, 2020

The phylum Cnidaria represents a close outgroup to Bilateria and includes familiar animals including sea anemones, corals, hydroids, jellyfish. Here we report genome sequencing assembly for true jellyfish Sanderia malayensis Rhopilema esculentum. homeobox gene clusters are characterised by interdigitation of Hox, NK, Hox-like genes revealing an alternate pathway ANTP class dispersal intact three ParaHox cluster. mitochondrial genomes linear but, unlike in Hydra, do not detect nuclear copies, suggesting that plastid necessarily prone integration. Genes sesquiterpenoid hormone production, typical arthropods, also now found cnidarians. Somatic germline cells both express piwi-interacting RNAs conserved cnidarian feature, evidence tissue-specific microRNA arm switching as is detected. Jellyfish reveal mosaic divergent genomic characters evolved from shared ancestral genetic architecture.

Language: Английский

---

The moulting arthropod: a complete genetic toolkit review

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2024, Volume and Issue: 99(6), P. 2338 - 2375

Published: July 22, 2024

ABSTRACT Exoskeletons are a defining character of all arthropods that provide physical support for their segmented bodies and appendages as well protection from the environment predation. This ubiquitous yet evolutionarily variable feature has been instrumental in facilitating adoption variety lifestyles exploitation ecological niches across environments. Throughout radiation produced more than one million described modern species, adaptability afforded by segmentation exoskeletons led to diversity is unrivalled amongst animals. However, because limited extensibility exoskeleton chitin cuticle components, they must be periodically shed replaced with new larger ones, notably accommodate growing individuals encased within. Therefore, grow discontinuously undergoing periodic moulting events, which follow series steps preparatory pre‐moult phase ecdysis itself post‐moult maturation exoskeletons. Each event represents particularly vulnerable period an arthropod's life cycle, so processes tightly regulated meticulously executed ensure successful transitions normal growth development. Decades research representative foundation understanding mechanisms involved. Building on this, studies continue develop test hypotheses presence function molecular including neuropeptides, hormones, receptors, so‐called early, late, fate genes, arthropod diversity. Here, we review literature comprehensive overview status accumulated knowledge genetic toolkit governing moulting. From biosynthesis regulation ecdysteroid sesquiterpenoid factors involved hormonal stimulation responses remodelling, identify commonalities differences, highlighting major gaps, groups. We examine available evidence supporting current models how components operate together prepare for, execute, recover ecdysis, comparing reports Chelicerata, Myriapoda, Crustacea, Hexapoda. Evidence generally highly taxonomically imbalanced, most based insect study systems. Biases also evident different phases processes, early triggers late effectors being least explored. Our synthesis contrasts reported observations reasonably plausible assumptions given taxonomic sampling, exposes weak or gaps need addressing. Encouragingly, advances genomics driving diversification tractable systems cataloguing putative toolkits previously under‐explored taxa. Analysis genome transcriptome data supported experimental investigations have validated “ultra‐conserved” core genes processes. The machinery likely evolved elaborations this conserved pathway backbone, but exploration needed characterise lineage‐specific changes novelties. Furthermore, linking these transformative innovations Arthropoda remains hampered untested assumptions. Promisingly however, emerging framework highlights avenues underlying genetics dynamic biology through complex physiology

Language: Английский

---

Ancestral Role of Ecdysis-Related Neuropeptides in Animal Life Cycle Transitions

Current Biology, Journal Year: 2020, Volume and Issue: 31(1), P. 207 - 213.e4

Published: Oct. 30, 2020

Language: Английский

---

Ontogeny of the Cytochrome P450 Superfamily in the Ornate Spiny Lobster (Panulirus ornatus)

International Journal of Molecular Sciences, Journal Year: 2024, Volume and Issue: 25(2), P. 1070 - 1070

Published: Jan. 15, 2024

Cytochrome P450s (CYP450s) are a versatile superfamily of enzymes known to undergo rapid evolution. They have important roles across growth and development pathways in crustaceans, although it is difficult characterise orthologs between species due their sequence diversity. Conserved CYP450s crustaceans those associated with ecdysteroidogenesis: synthesising breaking down the active moult hormone, 20-hydroxyecdysone. The complex life cycle ornate spiny lobster, Panulirus ornatus, relies on moulting order grow develop. Many these diverse stages been analysed establish comprehensive transcriptomic database for this species. transcripts putatively encoding were mapped using analysis identified stages. With aid phylogeny, 28 42 putative P. ornatus annotated, including well conserved Halloween genes, which involved ecdysteroidogenesis. Expression patterns determined that only subset can be detected each stage or tissue. Four Shed show overlapping expression metamorphosis adult tissues, suggesting pleotropic functions multiple within ornatus.

Language: Английский

---

Storage cell proliferation during somatic growth establishes that tardigrades are not eutelic organisms

Biology Open, Journal Year: 2024, Volume and Issue: 13(2)

Published: Feb. 15, 2024

ABSTRACT Tardigrades, microscopic ecdysozoans known for extreme environment resilience, were traditionally believed to maintain a constant cell number after completing embryonic development, phenomenon termed eutely. However, sporadic reports of dividing cells have raised questions about this assumption. In study, we explored tardigrade post-embryonic proliferation using the model species Hypsibius exemplaris. Comparing hatchlings adults, observed an increase in storage cells, responsible nutrient storage. We monitored via 5-ethynyl-2′-deoxyuridine (EdU) incorporation, revealing large numbers EdU+ during growth, which starvation halted. EdU incorporation associated with molting, vital development process involving cuticle renewal further growth. Notably, DNA replication inhibition strongly reduced and caused molting-related fatalities. Our study is first demonstrate molecular approaches that actively proliferate providing comprehensive insight into events throughout their somatic Additionally, our data underscore significance proper molting survival. This work definitely establishes tardigrades are not eutelic, offers insights cycle regulation, stress, damage management these remarkable creatures as genetic manipulation techniques emerge within field.

Language: Английский

---