Dimethylsulfoniopropionate and dimethylsulfide in the marine flatworm Convoluta roscoffensis and its algal symbiont

2001 ◽  
Vol 138 (1) ◽  
pp. 209-216 ◽  
Author(s):  
L. J. Stal ◽  
S. A. Van Bergeijk
Keyword(s):  
Algal Symbiont ◽  
Convoluta Roscoffensis

The specific identity of the algal symbiont in Convoluta roscoffensis

1967 ◽  
Vol 47 (2) ◽  
pp. 445-464 ◽  
Author(s):  
Mary Parke ◽  
Irene Manton
Keyword(s):  
Water Samples ◽  
Distinct Species ◽  
Free Living ◽  
Algal Symbiont ◽  
New Information ◽  
Golgi System ◽  
Electron Microscopes ◽  
Convoluta Roscoffensis ◽  
Specific Identity

The algal symbiont of Convoluta roscoffensis (Graff) has been studied with the light and electron microscopes both in situ in worms collected from four localities on the coast of Brittany and in various forms of isolates in culture. The same organism has also been obtained from populations of free-living monads collected from sand and water samples adjacent to the Convoluta colonies. Its structure and behaviour in culture are described and illustrated. Platymonas convolutae sp.nov. is a very distinct species with a rough-surfaced theca and a pyrenoid with some new characters not previously recorded in other members of the group. Some new information on scale and theca production from the Golgi system has also been obtained.

Symbiosis of the acoel flatworm Convoluta roscoffensis with the alga Platymonas convolutae

1974 ◽  
Vol 187 (1087) ◽  
pp. 221-234 ◽  
Keyword(s):  
Amino Acids ◽  
Carbon Fixation ◽  
Main Product ◽  
Indirect Evidence ◽  
Fixed Carbon ◽  
Free Living ◽  
Photosynthetic Carbon Fixation ◽  
Algal Symbiont ◽  
Photosynthetic Carbon ◽  
Convoluta Roscoffensis

Convoluta roscoffensis can carry out photosynthetic carbon fixation at rates comparable to free-living algae. The main product of fixation is mannitol, previously shown to be the main product accumulating in the isolated algal symbiont in pure culture. Since both eggs and mucus of Convoluta became radioactive when incubated in NaH 14 CO 3 in the light, photosynthetically fixed carbon can evidently move from alga to animal. Available evidence indicates that it is amino acids, not mannitol, which are released from the algae in Convoluta . The difficulty of separating algae from animal tissue prevented direct estimates of the amount of carbon moving, but indirect evidence indicated it may not be as high as in other autotroph-heterotroph associations. When Convoluta is incubated in the light in seawater containing NaH 14 CO 3 and certain amino acids (especially alanine), fixed 14 C is released to the medium as amino acids. Up to 8% of the total fixed carbon may be released in this way, and the effect is believed to be due to the external amino acids being able to penetrate the tissues and exchange with the radioactive amino acids as they move through the animal tissues. Pyruvic acid was also effective in causing the release of fixed 14 C.

Two Species of Algal Symbiont in Naturally Occurrin G Populations of Convoluta Roscoffensis

1982 ◽  
Vol 62 (1) ◽  
pp. 235-235 ◽  
Author(s):  
A. E. Mcfarlane
Keyword(s):  
Ultrastructural Level ◽  
Thylakoid Membranes ◽  
Mixed Population ◽  
Algal Symbionts ◽  
Plastid Envelope ◽  
South Wales ◽  
Algal Symbiont ◽  
Individual Worm ◽  
Green Flagellate ◽  
Convoluta Roscoffensis

Convoluta roscoffensis (Graff) has long been known for its symbiosis with a green flagellate definitively described from French stock as Platymonas convolutae by Parke and Manton (Parke & Manton, 1967). Provasoli subsequently discovered a species of Prasinocladus in a culture isolated from C. roscoffensis, but concluded that it was a surface contaminant of the animal (Provasoli, Yamasu & Manton, 1968).Populations of C. roscoffensis from Aberthaw, South Wales (Mettam, 1979), and eighteen sites on Guernsey have been studied. In most patches of the Aberthaw colony, and in two of the Guernsey sites, two algal symbionts have been found. One of the Guernsey, and one of the Aberthaw symbionts appear identical to Platymonas convolutae.They can be distinguished at the ultrastructural level by the presence of canaliculi which penetrate the pyrenoid, and are lined with the double-layered plastid envelope. In both cases the second flagellate shows the nucleus-pyrenoid complex typical of the genus Prasinocladus, where the nucleus penetrates the pyrenoid, and a pair of thylakoid membranes separate the pyrenoid from the starch shell (Parke & Manton, 1965). Neither symbiont has been identified specifically.It is also possible to distinguish the two symbionts in the living animals, since the cup-shaped pyrenoid of the Prasinocladus type is easily distinguished from the spherical condition in Platymonas using the light microscope. A mixed population of symbionts has never been found in an individual worm. For each patch of animals in a colony it was possible to establish the percentage of animals containing each symbiont. This ratio varies from patch to patch in the colony, but has remained remarkably constant within each patch over the six months it has been studied. The Prasinocladus type always predominates at Aberthaw, the Platymonas type being absent in places.

scholarly journals The complete genome sequence of the algal symbiont Dinoroseobacter shibae: a hitchhiker's guide to life in the sea

2009 ◽  
Vol 4 (1) ◽  
pp. 61-77 ◽  
Author(s):  
Irene Wagner-Döbler ◽  
Britta Ballhausen ◽  
Martine Berger ◽  
Thorsten Brinkhoff ◽  
Ina Buchholz ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Algal Symbiont ◽  
Dinoroseobacter Shibae

A Physiological Comparison of the Symbiotic Alga Platymonas Convolutae and its Free-Living Relatives

1970 ◽  
Vol 50 (1) ◽  
pp. 199-208 ◽  
Author(s):  
G. W. Gooday
Keyword(s):  
Recent Work ◽  
Pure Culture ◽  
Type Species ◽  
Organic Nitrogen ◽  
Soluble Carbohydrates ◽  
Symbiotic Relationship ◽  
Symbiotic Alga ◽  
Free Living ◽  
Unialgal Culture ◽  
Convoluta Roscoffensis

Platymonas convolutae Parke et Manton is the natural algal partner of the symbiotic worm Convoluta roscoffensis Graff (Parke & Manton 1967). Recent work by Provasoli, Yamasu & Manton (1968) has shown that although several algae can form a symbiotic relationship with the worm if supplied in unialgal culture, the natural symbiont is the most effective and is able to eliminate competitors. The alga can be cultured in a denned medium away from its partner, and this paper presents some physiological characteristics of the alga in pure culture in comparison with some of its free-living relatives, in particular the type species of the genus Platymonas, P. tetrathele G. S. West. The present investigation has been concerned mainly with the uptake of carbohydrates and the utilization of organic nitrogen. Other aspects that are included are the excretion of metabolites into the medium and the soluble carbohydrates found within the algae. In addition, culturing the algae has revealed a difference in behaviour of possible relevance to the symbiotic relationship.

Establishment of the symbiosis in Convoluta roscoffensis

1983 ◽  
Vol 63 (2) ◽  
pp. 419-434 ◽  
Author(s):  
A. E. Douglas
Keyword(s):  
Central Region ◽  
Related Species ◽  
Initial Contact ◽  
Structural Studies ◽  
Algal Population ◽  
Recognition Mechanism ◽  
Wide Range ◽  
Algal Photosynthesis ◽  
Convoluta Roscoffensis

Of a wide range of algae tested, juvenile Convoluta roscoffensis ingested only Platymonas convolutae, the natural symbiont; related species of the genera Platymonas, Prasinocladus and Tetraselmis; and Chlamydomonas coccoides. Platymonas convolutae was not ingested to a greater extent than Prasinocladus marinus, Tetraselmis tetrathele and Tetraselmis verrucosa, or taken up in preference to T. verrucosa when animals were exposed to a choice between the two species. Convoluta ingested fewer cells of C. coccoides than P. convolutae and related species. Uptake of P. convolutae was not affected by pretreatment of the cells with lectins or proteases, incubation in media of pH 5·0–9·0 or inhibition of algal photosynthesis, but was substantially reduced if the algae were killed.Cells of P. convolutae, Pr. marinus, T. tetrathele and T. verrucosa persisted and divided in juvenile Convoluta. The algal population in the worms started to increase 2–3 d after ingestion and within 15–20 d the animals were uniformly green. These algae formed a viable symbiosis with Convoluta and promoted the growth of the animals. In contrast, C. coccoides cells did not persist in Convoluta for more than 12–24 h a nd were probably disrupted.P. convolutae cells lost their thecae within a few days of ingestion and before migration from the central to sub-epidermal region of the animal. Animal vacuoles surrounded recently ingested thecate algae. Structural studies of the adult symbiosis suggest that the algae were also intracellular and enclosed in vacuoles.It is proposed that Convoluta discriminates against algae unrelated to P. convolutae on initial contact and in the central region of the host. The nature of the recognition mechanism(s) has not been established.

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