Evolving multicellularity is easy, especially in phototrophs and osmotrophs whose multicells feed like unicells. Evolving animals was much harder and unique; probably only one pathway via benthic 'zoophytes' with pelagic ciliated larvae allowed trophic continuity from phagocytic protozoa to gut-endowed animals. Choanoflagellate protozoa produced sponges. Converting sponge flask cells mediating ...

Surprisingly little is known of the toxic arsenal of cnidarian nematocysts compared to other venomous animals. Here we investigate the toxins of nematocysts isolated from the jellyfish Olindias sambaquiensis. A total of 29 unique ms/ms events were annotated as potential toxins homologous to the toxic proteins from diverse animal phyla, including cone-snails, snakes, spiders, scorpions, wasp, be...

We examined the foraging process in the jellyfish Sarsia tubulosa feeding on three types of prey: cirripede nauplii, cypris larvae, and Acartia tonsa copepodites. Clearance rate was used as measure of prey selectivity. To estimate maximal clearance rate (Fmax), we used a predictive encounter model with input parameters quantified from video observations. Both encounter rate and handling efficie...

The ionic events leading to discharge of in situ nematocysts were investigated in acontia excised from Aiptasia mutabilis Gravenhorst. The effect on discharge of various ionic solutions and ion channel blockers was tested. In the absence of Ca in the medium no discharge was elicited, whatever the composition of the medium. In the presence of lOmmolI" Ca total discharge was induced by NaSCN, Nal...

Cells that secrete proteins do so by a well-characterized route, the final step of which is the fusion of intracellular secretory granules with the overlying plasma membrane (Palade, 1975). This results in the exocytosis of the granule contents. Associated with this exocytosis is a swelling, of either the granules themselves or their contents. This swelling has been observed by light microscopy...

© 2016 Joule Inc. or its licensors CMAJ 1 A45-year-old otherwise healthy woman presented with a five-day history of a pruritic eruption on her left forearm that developed several minutes after accidentally brushing against a coral while snorkelling in the Mediterranean Sea. She reported initially feeling a stinging and burning sensation in her forearm, which was followed by the development of a...

The myxosporean species are typically defined by the size and shape of the spores released by vertebrate hosts. These are previously thought to be multicellular protozoans are to be considered animals by many scientists. Recent molecular studies suggest that they are related to Bilataria with being closer, but with Bilataria being somewhat closer in some genetic studies. The examination of fres...

In the sea anemone Anthopleura elegantissima contact between non-clonemates often elicits inter-clonal fighting, involving the application of nematocyst-laden fighting tentacles (acrorhagi) and the locomotory retreat of losing polyps. This study confirms that isoclonal aggregations of A. elegantissima display an inducible polymorphism, such that polyps at the inter-clonal boundaries (warriors) ...

The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non...

Many rock barnacles form close associations with other organisms, yet none are known to have become wholly parasitic. In a study of balanids inhabiting corals, we encountered a species-Pyrgoma monticulariae Gray, 1831-that depends on the coral for both habitat and food. In achieving this relationship it has gained control over certain metabolic activities of the coral, including calcification, ...