Optimal Egg Size in Marine Invertebrates: Theory and Phylogenetic Analysis of the Critical Relationship between Egg Size and Development Time in Echinoids

2000 ◽  
Vol 156 (2) ◽  
pp. 175-192 ◽  
Author(s):  
Don R. Levitan
Keyword(s):  
Phylogenetic Analysis ◽  
Egg Size ◽  
Development Time ◽  
Marine Invertebrates

scholarly journals Ancient coexistence of norepinephrine, tyramine, and octopamine signaling in bilaterians

2016 ◽  
Author(s):  
Philipp Bauknecht ◽  
Gáspár Jékely
Keyword(s):  
Phylogenetic Analysis ◽  
Adrenergic Receptors ◽  
Marine Invertebrates ◽  
Last Common Ancestor ◽  
Marine Animals ◽  
Adrenergic Signaling ◽  
Signaling Systems ◽  
Receptor Pharmacology ◽  
Α2 Receptors

AbstractNorepinephrine/noradrenaline is a neurotransmitter implicated in arousal and other aspects of vertebrate behavior and physiology. In invertebrates, adrenergic signaling is considered absent and analogous functions are performed by the biogenic amines octopamine and its precursor tyramine. These chemically similar transmitters signal by related families of GPCR in vertebrates and invertebrates, suggesting that octopamine/tyramine are the invertebrate equivalents of vertebrate norepinephrine. However, the evolutionary relationships and origin of these transmitter systems remain unclear. Using phylogenetic analysis and receptor pharmacology, here we establish that norepinephrine, octopamine, and tyramine receptors coexist in some marine invertebrates. In the protostomes Platynereis dumerilii (an annelid) and Priapulus caudatus (a priapulid) we identified and pharmacologically characterized adrenergic α1 and α2 receptors that coexist with octopamine α, octopamine β, tyramine type 1, and tyramine 2 receptors. These receptors represent the first examples of adrenergic receptors in protostomes. In the deuterostome Saccoglossus kowalewskii (a hemichordate), we identified and characterized octopamine α, octopamine β, tyramine type 1, and tyramine 2 receptors, representing the first example of these receptors in deuterostomes. S. kowalewskii also has adrenergic α1 and α2 receptors, indicating that all three signaling systems coexist in this animal. In phylogenetic analysis, we also identified adrenergic and tyramine receptor orthologs in xenacoelomorphs. Our results clarify the history of monoamine signaling in bilaterians. Since all six receptor families (two each for octopamine and tyramine and three for norepinephrine) can be found in representatives of the two major clades of Bilateria, the protostomes and the deuterostomes, all six receptors coexisted in the protostome-deuterostome last common ancestor. Adrenergic receptors were lost from most insects and nematodes and tyramine and octopamine receptors were lost from most deuterostomes. This complex scenario of differential losses cautions that octopamine signaling in protostomes is not a good model for adrenergic signaling in deuterostomes, and that the studies of marine animals where all three transmitter systems coexist will be needed for a better understanding of the origin and ancestral functions of these transmitters.

scholarly journals Transgenerational effects of UV-B radiation on egg size, fertilization, hatching and larval size of sea urchins Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7598
Author(s):  
Jingyun Ding ◽  
Lingling Zhang ◽  
Jiangnan Sun ◽  
Dongtao Shi ◽  
Xiaomei Chi ◽  
...  
Keyword(s):  
Egg Size ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Marine Invertebrate ◽  
Ultraviolet B ◽  
Hatching Rate ◽  
Strongylocentrotus Intermedius ◽  
Transgenerational Effects ◽  
Larval Size ◽  
First Time

Transgenerational effects are important for phenotypic plasticity and adaptation of marine invertebrates in the changing ocean. Ultraviolet-B (UV-B) radiation is an increasing threat to marine invertebrates. For the first time, we reported positive and negative transgenerational effects of UV-B radiation on egg size, fertilization, hatchability and larval size of a marine invertebrate. Strongylocentrotus intermedius exposed to UV-B radiation showed positive transgenerational effects and adaptation on egg size, hatching rate and post-oral arm length of larvae. Negative transgenerational effects were found in body length, stomach length and stomach width of larvae whose parents were exposed to UV-B radiation. Sires probably play important roles in transgenerational effects of UV-B. The present study provides valuable information into transgenerational effects of UV-B radiation on fitness related traits of sea urchins (at least Strongylocentrotus intermedius).

scholarly journals Linking genome size variation to population phenotypic variation within the rotifer, Brachionus asplanchnoidis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Claus-Peter Stelzer ◽  
Maria Pichler ◽  
Anita Hatheuer
Keyword(s):  
Embryonic Development ◽  
Genome Size ◽  
Genomic Dna ◽  
Egg Size ◽  
Development Time ◽  
Size Variation ◽  
Conclusive Evidence ◽  
Heritable Variation ◽  
Genome Size Variation ◽  
Mutational Change

AbstractEukaryotic organisms usually contain much more genomic DNA than expected from their biological complexity. In explaining this pattern, selection-based hypotheses suggest that genome size evolves through selection acting on correlated life history traits, implicitly assuming the existence of phenotypic effects of (extra) genomic DNA that are independent of its information content. Here, we present conclusive evidence of such phenotypic effects within a well-mixed natural population that shows heritable variation in genome size. We found that genome size is positively correlated with body size, egg size, and embryonic development time in a population of the monogonont rotifer Brachionus asplanchnoidis. The effect on embryonic development time was mediated partly by an indirect effect (via egg size), and a direct effect, the latter indicating an increased replication cost of the larger amounts of DNA during mitosis. Our results suggest that selection-based change of genome size can operate in this population, provided it is strong enough to overcome drift or mutational change of genome size.

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