Porifera Flashcards
What are some characteristics of the Porifera?
Sponges, the simplest multi-cellular animals, acoelomate (no blood, circulatory system), weak, sessile, filter feeders
What has much of the research been directed towards?
Composition of the microbiome (~40% of sponge biomass)
Understanding multicellularity
Graft rejection and cytotoxicity
Use of secondary metabolites
When was the first sponge genome sequenced and what species was it?
2010, Amphimedon queenslandica
When was the first bacterial pathogen of sponge disease isolated and what is its name?
2002, NW4327
What species is currently being affected by a disease-like syndrome?
Ianthella basta in Torres Strait and Great Barrier Reef
How do sponge cells aggregate with one another?
Presence of calcium ions and cell surface receptors essential
Requires aggregation factor (AF), a multiprotein complex which associates with aggregation receptor (AR) on cell surface
AF and AR binding is enhanced by lectins
What are the PRRs found in porifera?
TLRs (abundant, localised on sponge surface, recognise PAMPs), NLRs (mostly intracellular), lectins, LPS receptors (SLIP)
What is SLIP?
S. domuncula LPS interacting protein. Its interaction with different LPS regions mediates recognition between symbionts and pathogens
What happens when LPS binds to SLIP?
LPS binding to SLIP promotes its dimerisation and triggers intracellular signalling through interaction with poriferan MyD88, an adaptor protein possessing 2 protein interaction domains. There is an elevated expression of MyD88 and macrophage expressed gene, a perforin-like executing molecule with antibacterial (Gram negative) effect.
How does Porifera react to pathogens (cellular processes)?
Phagocytosis, apoptosis, cell-mediated cytoxocity usually via soluble molecules
How does Porifera react to pathogens (soluble effector molecules)?
Their presence is dominant, 100s of antimicrobial compounds isolated from sponges or their symbionts, including secondary metabolites
What are secondary metabolites and what are some of the main groups?
Soluble effector molecules with potential anti-infective/anti-cancer properties
Alkaloids (e.g. caffeine)
Terpanoids (e.g. menthol)
Phenols
What is an example of secondary metabolite isolated from a sponge with anti-cancer properties?
Halichondron B, from Halicondria okadi. An approved anti-cancer. Binds to tubulin, blocks formation of microtubules, cell dies via apoptosis. Difficulty in obtaining supplies
What is an example of secondary metabolite isolated from a sponge with anti-inflammatory properties?
Manoalide. Withdrawn due to poor tissue absorption. Inhibits phospholipase A2
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