The major light-harvesting pigment-protein complex of Mamiella gilva (Parke et Rayns) Moestrup (Micromonadophyceae, Chlorophyta) was isolated by lithium dodecyl sulphate polyacrylamide gel electrophoresis at 4°C. This complex is similar to that of Mantoniella squamata (Manton et Parke) Desikachary and Micromonas pusilla (Butcher) Manton et Parke with regard to molecular weight, absorption spectrum, and immunochemical cross-reactivity. On the other hand, the light-harvesting complex of Chlamydomonas reinhardtii P. Dangeard is quite different. The distribution of this unusual light-harvesting complex, which has to date been reported only in Mamiella, Mantoniella, and Micromonas, suggests a line of evolution in the Micromonadophyceae separate from all other green algae. In addition, the inclusion of the naked Micromonas in this group suggests that Micromonas should be included with Mamiella and Mantoniella in the Mamiellales, an order which is presently defined by scale type.
Sequences from the Stramenopile class Eustigmatophyceae are rarely reported in metabarcoding studies, and when they have been reported, there are very few haplotypes. We hypothesized that the paucity of eustigmatophyte species detected in these studies may be a result of the metabarcoding techniques used, which have primarily employed universal ribosomal RNA gene regions. In this study, we examined environmental DNA samples from 22 sites in southwestern Virginia, some of which had previously been studied using ribosomal RNA analysis. We used metabarcoding techniques targeting the plastid rbcL gene with new primers designed to produce a 370 bp amplicon from all lineages of the Eustigmatophyceae in a reference collection. The amplicons were then analyzed with DADA2 to produce amplicon sequence variants (ASVs). Our results revealed 184 rbcL haplotypes that can be tentatively assigned to the Eustigmatophyceae from these sites, representing much higher diversity than has been detected by ribosomal DNA-based studies. The techniques employed can be used for future studies of population structure, ecology, distribution, and diversity of this class. With these techniques, it should be possible to make realistic estimates of the species-level diversity of the Eustigmatophyceae on local, regional, and perhaps global scales.
ABSTRACT Pigments were isolated from Mesostigma viride Lauterborn by reversed‐phase high‐performance liquid chromatography and compared to standards from Chlamydomonas reinhardtii Dang. and Bryopsis plumose (Huds.) Ag. M. viride possesses chlorophylls a and b , α and β‐carotenes, and the xanthophylls siphonaxanthis, siphonein, neoxanthin, violaxanthin and echinenone. In addition, three unidentified xanthophylla were detected. Neither lutein nor zeaxanthin were detected. The pigment composition of M. viride was similar to that of B. plumosa which had chlorophylls a and b, ɛ‐ and α‐carotenes, siphonaxanthin, siphonein, neoxanthin, violaxanthin, and two of the unidentified xanthophylls found in M. viride. The similarities in the pigments of Mesostigma and Bryopsis and other characters suggest that Mesostigma may be related to a flagellate ancestor of the Ulvophyceae.
We provide molecular phylogenetic evidence that the obscure genera Palmophyllum Kütz. and Verdigellas D. L. Ballant. et J. N. Norris form a distinct and early diverging lineage of green algae. These palmelloid seaweeds generally persist in deep waters, where grazing pressure and competition for space are reduced. Their distinctness warrants recognition as a new order, the Palmophyllales. Although phylogenetic analyses of both the 18S rRNA gene and two chloroplast genes ( atp B and rbc L) are in agreement with a deep‐branching Palmophyllales, the genes are in conflict about its exact phylogenetic placement. Analysis of the nuclear ribosomal DNA allies the Palmophyllales with the prasinophyte genera Prasinococcus and Prasinoderma (Prasinococcales), while the plastid gene phylogeny placed Palmophyllum and Verdigellas as sister clade to all other Chlorophyta.
The green algae and land plants are generally assumed to share a common system of harvesting light energy for photosynthesis based on the plastid Chl a/b protein LHCs, which are encoded by the nuclear Cab gene family. Indeed, the polypeptide constituents of most of these complexes are clearly homologous, as demonstrated by sequence analysis (Pichersky and Green, 1990) and immunochemical crossreactivity (Thornber et al., 1991). However, one group of small green flagellates, members of the order Mamiellales of the Micromonadophyceae, have a major LHC that does not display immunochemical cross-reactivity to the major LHC of other green plants (Fawley et al., 1990). The LHC of these organisms also contains the xanthophyll prasinoxanthin and a Chl c-like pigment in addition to Chl b, a combination of pigments not found in land plants or other types of green algae (Fawley, 1992). Some members of the Mamiellales, notably Mantoniella squamata (Manton et Parke) Desikachary, have been considered by some to represent the most primitive type in the green algae (Melkonian, 1984; van den Hoek et al., 1988). Therefore, it was of interest to us to use sequence analysis to determine whether or not the polypeptides of the LHC of the Mamiellales are homologous to those of other green algae and land plants. In addition, the comparison of a highly divergent or primitive LHC type with other LHCs could provide insight on important structural features of the proteins. A cDNA library from poly(A)+ RNA from Mantoniella squamata was constructed using the SuperScript Lambda System (BRL). The library was screened with polyclonal antisera raised against the major polypeptide of a LHC of M. squamata (Lee et al., 1992). A positive clone (MScab-1) was subcloned into pBluescript II for restriction mapping with BamHI, HindIII, KpnI, PstI, Sad, SpnI, and XbaII. Appropriate fragments were sequenced in both directions using M13mpl8 and M13mpl9 vectors and Sequenace 2.0 (United States Biochemical). Sequencing revealed that the 900-bp clone contained an open reading frame corresponding to a 231-amino acid polypeptide with a molecular mass of 25.4 kD. The derived amino
ABSTRACT The biosynthesis of the light‐harvesting complex (LHC) polypeptides of the green flagellate Mantoniella squamata (Manton et Parke) Desikachary (Micromonadophyceae, Chlorophyta) was examined by in vivo polypeptide labeling and immunoprecipitation of in vitro translation products. Using protein synthesis inhibitors, the LHC polypeptides were shown to be synthesized on 80S cytoplasmic ribosomes and not in the chloroplasts of cells. Poly (A)+ RNA was isolated and proteins were synthesized by a rabbit reticulocyte lysate system, with antisera raised against M. squamata LHC used for immunoprecipitation from the translation products. One polypeptide 3‐5 kDa larger than mature LHC polypeptides was immunoprecipitated. These studies indicate that although the LHC of M. squamata is quite different from the LHC of most green plants, the LHC polypeptides are synthesized as precursors in the cytoplasm of the cell and suggest that the genes encoding these polypeptides are located in the nucleus.
A new form of chlorophyll c has been isolated from the pyrmnesiophyte Pavlova gyrans Butcher. This pigment is spectrally similar to chlorophyll c(2), but all the absorption maxima (454, 583, and 630 nm in diethyl ether) are shifted 4 to 6 nanometers to longer wavelengths. The new pigment can be separated from other chlorophyll c-type pigments by reversed-phase high performance liquid chromatography and thin layer chromatography. Both chlorophylls c(1) and c(2) are found with the new chlorophyll c pigment in P. gyrans, and it has also been detected in the chrysophyte Synura petersenii Korsh. The light-harvesting function of the new chlorophyll c pigment is indicated by its presence along with chlorophyll c(1) and c(2) in a light-harvesting pigment-protein complex isolated from P. gyrans in which chlorophyll c pigments efficiently transfer absorbed light energy to chlorophyll a.
ABSTRACT Thirty‐five green algal species, representing 17 orders in 5 classes, were examined for the presence of the xanthophyll loroxanthin by reversed‐phase high‐performance liquid chromatography. Of these, 16 possessed loroxanthin, including at least one member of each class of green algae. The distribution of loroxanthin as established by this and previous studies is disjunct within the Chlorophyta and does not appear to have any taxonomic significance. Most of the green algae examined possessed one or more xanthophyll pigments that have not been found in land plants.
Chlorophylls c 1 and c 2 have been separated from total pigment extracts of the alga Pavlova gyrans Butcher using a reversed-phase high-performance liquid chromatography system. Pigments were separated on a 5 micrometer C18 column (25 centimeters × 4.6 millimeters) using a gradient of methanol-acetonitrile-water. Other photosynthetic pigments were also well resolved by the system used. The separation system described may replace current thin layer chromatography methods for qualitative and quantitative determination of chlorophyll c species.
