Search results for "Prasinophyceae"
showing 8 items of 8 documents
Comparative analysis of the composition of two chlorophyll-b-containing light-harvesting complexes.
1990
The major light-harvesting complexes from Mantoniella squamata (Prasinophyceae) and from Chlorella fusca (Chlorophyceae) were analyzed with respect to polypeptide composition and pigmentation. It was found that the polypeptides of Mantoniella are smaller than those of Chlorella and bind twice the amount of pigment. We assume that the amount of pigment per polypeptide is of ecological as well as of taxonomical importance.
Ultrastructure and freeze-fracture studies of the thylakoids ofMantoniella squamata (Prasinophyceae)
1988
The ultrastructure and the supramolecular organization of the thylakoids of the small green flagellate,Mantoniella squamata, were examined in thin sections and freeze-fracture preparations. The whole chloroplast is tightly packed with thylakoids, which show a pattern of meandering, branching and/or anastomosing membranes. In freeze-fracture preparations only two fracture-faces can be distinguished: the PF- and the EF-face. The PF-face has a much higher particle density than the EF-face (PF: 4086 particles/μm2; EF: 865 particles/μm2). The EF-face is not as uniform as the PF-face. The areas which are packed with particles probably correspond to closely appressed thylakoid regions or adhesive …
The Existence of Chlorophyll c in the Chl b‐Containing, Light‐Harvesting Complex of the Green Alga Mantoniella squamata (Prasinophyceae)
1988
The prasinophycean alga Mantoniella contains, in addition to Chl a and b, at least a third green pigment which is functionally active in the light-harvesting antenna. This third Chl was isolated in order to elucidate its chemical structure. The absorption and fluorescence spectra were measured not only from the purified pigment but also from its pheophytin and its methylpheophorbide. The spectra were compared with those of authentic Chl c-1 and c-2, which were isolated from the diatom Nitzschia sp. and with Mg-DVPP (purified from Rhodobacter). The results show that the pigment from Mantoniella compares best with Chl c-1. In order to clarify the spectral data, Chl c-1 and c-2, Mg-DVPP, and t…
Purification and identification of chlorophyll c1 from the green alga Mantoniella squamata
1987
Abstract The prasinophycean alga Mantoniella squamata contains besides chlorophyll a and b a third chlorophyll c -like pigment in its light-harvesting antenna. This third chlorophyll was purified by reverse phase and polyethylene chromatography in order to identify its chemical structure. The absorption and fluorescence spectra were measured not only from the doubly purified pigment, but also from its Mg-free derivates. The spectra were compared with those of authentic chlorophyll c and of Mg-2,4-desethyl-2,4-divinylpheoporphyrin a 5 monomethyl ester which was isolated from Rhodobacter capsulata . The results show that the pigment from Mantoniella agrees best with chlorophyll c 1 . In order…
Ancient recruitment by chromists of green algal genes encoding enzymes for carotenoid biosynthesis.
2008
Chromist algae (stramenopiles, cryptophytes, and haptophytes) are major contributors to marine primary productivity. These eukaryotes acquired their plastid via secondary endosymbiosis, whereby an early-diverging red alga was engulfed by a protist and the plastid was retained and its associated nuclear-encoded genes were transferred to the host genome. Current data suggest, however, that chromists are paraphyletic; therefore, it remains unclear whether their plastids trace back to a single secondary endosymbiosis or, alternatively, this organelle has resulted from multiple independent events in the different chromist lineages. Both scenarios, however, predict that plastid-targeted, nucleus-…
Three-dimensional crystallization of the light-harvesting complex from Mantoniella squamata (Prasinophyceae) requires an adequate purification proced…
1995
Abstract We present a new purification procedure for the light-harvesting complex of Mantoniella squamata whereupon three-dimensional crystallization succeeded. Previous purification methods were based on density centrifugations as the only separating principle. We have extended this preparation procedure by applying anion-exchange and molecular-sieve chromatography techniques. Purity and stability of the complex were proved by denaturing and non-denaturing polyacrylamide-gel electrophoresis, and spectroscopic measurements. With respect to contaminating lipids the purified pigment-protein complex was examined by thin-layer chromatography and the aggregation and/or oligomeric states were inv…
THE LIGHT-HARVESTING SYSTEM OF THE UNICELLULAR ALGA Mantoniella squamata (PRASINOPHYCEAE): EVIDENCE FOR THE LACK OF A PHOTOSYSTEM I-SPECIFIC ANTENNA …
1993
The light-harvesting complexes (LHC) were isolated from the unicellular alga Mantoniella squamata (Prasinophyceae) by sucrose-density centrifugation. Beside the major LHC (II), a photosystem I complex was obtained that could be dissociated into a photosystem I core complex and an associated LHC I. In contrast to other chlorophyll b-containing antennae, both LHC II as well as LHC I were observed to be identical with respect to the following features: the molecular weights, the isoelectric points and the retention behavior on anion-exchange chromatography of the apoproteins, the pigment content and the absorption and fluorescence spectra
Reconstitution of Light-Harvesting Complexes from Chlorella fusca (Chlorophyceae) and Mantoniella squamata (Prasinophyceae)
1993
Abstract Reconstitution experiments of light-harvesting complexes were performed with the green alga Chlorella fusca and the chlorophyll c-containing prasinophyte Mantoniella squamata using a modified method according to Plumley and Schmidt [Proc. N atl. Acad. Sei. U .S.A . 84, 146 -150 (1987)]. Changing the pigment supply quantitatively or qualitatively in the reconstitution mixture homologous and heterologous reconstitutes were obtained. In contrast to higher plants, light-harvesting polypeptides from green algae are able to bind the chlorophylls as well as the xanthophylls in different stoichiometries. Heterologous reconstitutes of M . squamata polypeptides give further evidence for a r…