The alga Volvox carteri represents one of the simplest multicellular organisms. Its extracellular matrix (ECM) is modified under developmental control, e.g. under the influence of the sex-inducing pheromone that triggers development of males and females at a concentration below 10(-16) M. A novel ECM glycoprotein (pherophorin-S) synthesized in response to this pheromone was identified and characterized. Although being a typical member of the pherophorins, which are identified by a C-terminal domain with sequence homology to the sex-inducing pheromone, pherophorin-S exhibits a completely novel set of properties. In contrast to the other members of the family, which are found as part of the insoluble ECM structures of the cellular zone, pherophorin-S is targeted to the cell-free interior of the spherical organism and remains in a soluble state. A main structural difference is the presence of a polyhydroxyproline spacer in pherophorin-S that is linked to a saccharide containing a phosphodiester bridge between two arabinose residues. Sequence comparisons indicate that the self-assembling proteins that create the main parts of the complex Volvox ECM have evolved from a common ancestral gene.
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http://dx.doi.org/10.1093/emboj/16.1.25 | DOI Listing |
New Phytol
February 2025
Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, 9000, Belgium.
A unique cell size-sensing mechanism is at the heart of the life cycle of diatoms. During population growth, cell size decreases until a sexual size threshold (SST) is reached, below which cells become sexually competent. In most pennate diatoms, the two mating types undergo biochemical and behavioral differentiation below the SST, although the molecular pathways underlying their size-dependent maturation remain unknown.
View Article and Find Full Text PDFOrg Lett
August 2024
Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia.
The peptide sex-inducing pheromone SIP () bearing an unusual sulfated aspartic acid residue induces sexual reproduction in diatom populations. Herein, we report the first total synthesis of SIP using both a sulfated building block approach and a solid-phase peptide synthesis (SPPS)-compatible late-stage sulfation strategy to assemble the natural product. The modular approaches provide concise routes to useful quantities of the natural product for future structure activity relationship studies examining the role of SIP in diatom biology.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2023
Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University Jena, Lessingstrasse 8, 07743, Jena, Germany.
Diatoms are abundant unicellular microalgae, responsible for ≈20 % of global photosynthetic CO fixation. Nevertheless, we know little about fundamental aspects of their biology, such as their sexual reproduction. Pheromone-mediated chemical communication is crucial for successful mating.
View Article and Find Full Text PDFISME J
February 2021
Protistology and Aquatic Ecology, Department of Biology, Ghent University, 9000, Ghent, Belgium.
Sexual reproduction is a fundamental phase in the life cycle of most diatoms. Despite its role as a source of genetic variation, it is rarely reported in natural circumstances and its molecular foundations remain largely unknown. Here, we integrate independent transcriptomic datasets to prioritize genes responding to sex inducing pheromones (SIPs) in the pennate diatom Seminavis robusta.
View Article and Find Full Text PDFProteomes
September 2018
Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA.
The recent identification of catalytically active peptidylglycine α-amidating monooxygenase (PAM) in Chlamydomonas reinhardtii, a unicellular green alga, suggested the presence of a PAM-like gene and peptidergic signaling in the last eukaryotic common ancestor (LECA). We identified prototypical neuropeptide precursors and essential peptide processing enzymes (subtilisin-like prohormone convertases and carboxypeptidase B-like enzymes) in the genome. Reasoning that sexual reproduction by C.
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