The Specialist Marine Herbivore Grows Faster on a Less Utilized Algal Diet.

AbstractMany small specialist herbivores utilize their food resources both for nutrition and as a structural refuge or resource. Trophic linkage cannot solely be inferred from physical association of herbivores with a potential food item, because herbivores may temporarily inhabit algae or plants on which they do not feed. , a small sacoglossan sea slug, consumes and sequesters chloroplasts from the siphonaceous, chlorophytic alga ; it also maintains moderate densities on this alga.

Algal Sources of Sequestered Chloroplasts in the Sacoglossan Sea Slug Elysia crispata Vary by Location and Ecotype.

Sacoglossan sea slugs feed by suctorially consuming siphonaceous green algae. Most sacoglossan species are feeding specialists, but the Caribbean coral reef-dwelling Elysia crispata is polyphagous and sequesters chloroplasts from multiple algal species into cells lining its digestive diverticulum for use in photosynthesis. We have used sequences of the chloroplast-encoded rbcL gene to compare the chloroplast donor algae in five populations of E.

A draft genome assembly of the solar-powered sea slug Elysia chlorotica.

Elysia chlorotica, a sacoglossan sea slug found off the East Coast of the United States, is well-known for its ability to sequester chloroplasts from its algal prey and survive by photosynthesis for up to 12 months in the absence of food supply. Here we present a draft genome assembly of E. chlorotica that was generated using a hybrid assembly strategy with Illumina short reads and PacBio long reads.

A Preliminary Molecular and Phylogenetic Analysis of the Genome of a Novel Endogenous Retrovirus in the Sea Slug Elysia chlorotica.

An endogenous retrovirus that is present in the sea slug Elysia chlorotica is expressed in all individuals at the end of the annual life cycle. But the precise role of the virus, if any, in slug senescence or death is unknown. We have determined the genomic sequence of the virus and performed a phylogenetic analysis of the data.

FISH labeling reveals a horizontally transferred algal (Vaucheria litorea) nuclear gene on a sea slug (Elysia chlorotica) chromosome.

The horizontal transfer of functional nuclear genes, coding for both chloroplast proteins and chlorophyll synthesis, from the food alga Vaucheria litorea to the sea slug Elysia chlorotica has been demonstrated by pharmacological, polymerase chain reaction (PCR), real time PCR (qRT-PCR), and transcriptome sequencing experiments. However, partial genomic sequencing of E. chlorotica larvae failed to find evidence for gene transfer.

Transcriptomic evidence for the expression of horizontally transferred algal nuclear genes in the photosynthetic sea slug, Elysia chlorotica.

Analysis of the transcriptome of the kleptoplastic sea slug, Elysia chlorotica, has revealed the presence of at least 101 chloroplast-encoded gene sequences and 111 transcripts matching 52 nuclear-encoded genes from the chloroplast donor, Vaucheria litorea. These data clearly show that the symbiotic chloroplasts are translationally active and, of even more interest, that a variety of functional algal genes have been transferred into the slug genome, as has been suggested by earlier indirect experiments. Both the chloroplast- and nuclear-encoded sequences were rare within the E.

Cell biology of the chloroplast symbiosis in sacoglossan sea slugs.

Chloroplasts removed from their species of origin may survive for various periods and even photosynthesize in foreign cells. One of the best studied and impressively long, naturally occurring examples of chloroplast persistence, and function inside foreign cells are the algal chloroplasts taken up by specialized cells of certain sacoglossan sea slugs, a phenomenon called chloroplast symbiosis or kleptoplasty. Among sacoglossan species, kleptoplastic associations vary widely in length and function, with some animals immediately digesting chloroplasts, while others maintain functional plastids for over 10 months.

Foraging behavior under starvation conditions is altered via photosynthesis by the marine gastropod, Elysia clarki.

It has been well documented that nutritional state can influence the foraging behavior of animals. However, photosynthetic animals, those capable of both heterotrophy and symbiotic photosynthesis, may have a delayed behavioral response due to their ability to photosynthesize. To test this hypothesis we subjected groups of the kleptoplastic sea slug, Elysia clarki, to a gradient of starvation treatments of 4, 8, and 12 weeks plus a satiated control.

PHYLOGENETIC ANALYSIS OF THE LARGE SUBUNIT RUBISCO GENE SUPPORTS THE EXCLUSION OF AVRAINVILLEA AND CLADOCEPHALUS FROM THE UDOTEACEAE (BRYOPSIDALES, CHLOROPHYTA)(1).

The placement of Avrainvillea and Cladocephalus in the family Udoteaceae (order Bryopsidales) has been questioned on the basis of nuclear, plastid, and other ultrastructural characteristics unique to these genera. Bayesian analysis of the chloroplast-encoded LSU RUBISCO (rbcL) gene showed that the Udoteaceae is paraphyletic. Cladocephalus luteofuscus (P.

Microscopic, biochemical, and molecular characteristics of the Chilean Blob and a comparison with the remains of other sea monsters: nothing but whales.

We have employed electron microscopic, biochemical, and molecular techniques to clarify the species of origin of the "Chilean Blob," the remains of a large sea creature that beached on the Chilean coast in July 2003. Electron microscopy revealed that the remains are largely composed of an acellular, fibrous network reminiscent of the collagen fiber network in whale blubber. Amino acid analyses of an acid hydrolysate indicated that the fibers are composed of 31% glycine residues and also contain hydroxyproline and hydroxylysine, all diagnostic of collagen.

PROLINE BETAINE: A UNIQUE OSMOLYTE IN AN EXTREMELY EURYHALINE OSMOCONFORMER.

The extremely euryhaline mollusc, Elysia chiorotica, does not utilize intracellular free amino acids for cell volume regulation during osmotic stress. Instead, Elysia utilizes an osmolyte previously unknown from animals, proline betaine. Although proline betaine occurs in some plants and Elysia forms a symbiosis with an algae, the proline betaine in Elysia seems to be a product of the animal.

Ultrastructure of the heart of the marine mussel, Geukensia demissa.

The structure of the heart of Geukensia demissa, a common object of physiological and biochemical investigation, is described by scanning, transmission and freeze-fracture electron microscopy. A single-cell epithelial layer covers the ventricle, but an endothelium is lacking. Myofibers are small (6-7 μm diam.