During the last ten years I have studied different aspects of blood circulation in three species of tunicates, and have attempted, with only partial success, to publish the results in the scientific literature. My account of this work not only may describe interesting biology, but also explore social and practical aspects of working in the science community.
First, what are tunicates and why are they interesting. They are group of animals that can be found attached to boats, docks, and shoreline rocks around the world, with some species floating in the open ocean. Tunicates represent a subgroup of the chordate phylum, animals that have a notochord at some stage of their lives. We are also chordates because we have a notochord for a brief period as we grow in the womb. Our notochord develops into into a spinal column, thus we belong to the vertebrate sub-phylum. The tunicate notochord is usually just eliminated as it matures. Tunicates are the non-vertebrate group most related to us.
The name tunicate comes from their unique tunic, or coat. I is made of a tough material containing cellulose, unusual because cellulose is typically produced by plants. No animals other than tunicates can synthesize cellulose, and it is thought that the genes specifying the enzymes that make cellulose were transferred from plants to the first ancestor of the tunicates.
Tunicates, like most invertebrate marine organisms, develop through two stages, as butterflies do. The first stage is called a tadpole, although of course it isn't a frog. Tunicate tadpoles, typically only a few mm long, have a head and tail and swim like a tadpole for a day or two before they attach to a solid surface and metamorphose into their mature form. Solitary tunicate species release eggs and sperm into the water to produce more tadpoles. Colonial species also produce eggs and sperm but in addition are able to also reproduce asexually to generated colonies of identical animals, or clones. I will discuss three research projects in inverse chronological order, i.e. the most recent first.
HINT: When reading material with figures at the end, open two windows in your browser, put the figures in one and the text you are reading in the other.
IMAGES: Three stages in the growth of a Botrylloides colony.
SYNOPSIS: Contractions of ampullae are often irregular, passing through periods of complete synchrony and asynchrony with neighbors, a pattern indicating entrainment. Periods of synchrony follow no repeating pattern, but are chaotic. Surgically detached ampullae continue to contract, but with extreme regularity, thus chaotic behavior in the colony results from interactions between ampullae.
Jun 2021 submitted to BMC Zoology;
Jun 2021 MS displayed on preprint server: Research Square;
Jan 2022 no referees asigned, even after several requests; MS withdrawn;
Mar 2022 revised MS submitted to PeerJ;
+ 3 days: rejected "it is a data paper and we don't publish data papers".
IMAGES: Three stages in the growth of the Ciona tunicate.
SYNOPSIS: The circulatory system in a young animal can be described as a collection of loops, with blood cells making a complete transit of the animal every 11 seconds. The system is closed and there are no significant pools of blood.
Mar 2018 submitted to PeerJ;
+3 days: rejected; "it is a methods paper and we don't publish methods papers";
Mar 2018: submitted to the reprint server bioRxiv; rejected without explanation even after appeal.
Apr 2018: my current PDF version
IMAGES: Mature animal before and after staining.
SYNOPSIS: The transparency of the body wall enables easy examination of blood circulation throughout the animal by following blood cells. Injection of fluorescent dextran into the circulation reveals that the circulatory is closed, since the dextran remains in the circulation for times comparable to those seen in mammals. Vessels leaving the peristaltic heart progressively bifurcate at both ends, in contrast to the geometry seen in insects with open circulatory systems.
Jul 2014 submitted to Biol Bul; rejected;
Jul 2014 submitted to J Invert Biol; read by 3 referees, publication possible;
Apr 2015 a new editor assigned to journal; rejected, saysd editorial process must start anew;
Oct 2015 published on preprint server bioRxiv
Jun 2016 submitted to PeerJ;
Dec 2016 published on PeerJ server.