Acuminolide A: Structure and Bioactivity of a New Polyether Macrolide from Dinoflagellate <i>Dinophysis acuminata</i>

Acuminolide A (<b>1</b>), along with pectenotoxin II (PTX-2), dinophysistoxin I (DTX-1), okadaic acid (OA), and 7-<i>epi</i>-PTX-2 <i>seco</i> acid, was isolated from a large-scale cultivation of the dinoflagellate <i>Dinophysis acuminata</i>. The new 33-membered macrolide <b>1</b> was characterized by detailed analysis of 2D NMR and MS data. Its relative stereochemistry was elucidated on the basis of ROESY correlations and <i>J</i>-based analysis. In contrast to the other well-known toxins that were isolated, <b>1</b> showed no cytotoxicity against four cancer cell lines but caused potent stimulation of actomyosin ATPase activity

List of genes in the <i>Teleaulax amphioxeia</i> plastid genome (143 total).

<p>List of genes in the <i>Teleaulax amphioxeia</i> plastid genome (143 total).</p

The Plastid Genome of the Cryptomonad <i>Teleaulax amphioxeia</i>

<div><p><i>Teleaulax amphioxeia</i> is a photosynthetic unicellular cryptophyte alga that is distributed throughout marine habitats worldwide. This alga is an important plastid donor to the dinoflagellate <i>Dinophysis caudata</i> through the ciliate <i>Mesodinium rubrum</i> in the marine food web. To better understand the genomic characteristics of <i>T</i>. <i>amphioxeia</i>, we have sequenced and analyzed its plastid genome. The plastid genome sequence of <i>T</i>. <i>amphioxeia</i> is similar to that of <i>Rhodomonas salina</i>, and they share significant synteny. This sequence exhibits less similarity to that of <i>Guillardia theta</i>, the representative plastid genome of photosynthetic cryptophytes. The gene content and order of the three photosynthetic cryptomonad plastid genomes studied is highly conserved. The plastid genome of <i>T</i>. <i>amphioxeia</i> is composed of 129,772 bp and includes 143 protein-coding genes, 2 rRNA operons and 30 tRNA sequences. The DNA polymerase III gene (<i>dna</i>X) was most likely acquired via lateral gene transfer (LGT) from a firmicute bacterium, identical to what occurred in <i>R</i>. <i>salina</i>. On the other hand, the <i>psb</i>N gene was independently encoded by the plastid genome without a reverse transcriptase gene as an intron. To clarify the phylogenetic relationships of the algae with red-algal derived plastids, phylogenetic analyses of 32 taxa were performed, including three previously sequenced cryptophyte plastid genomes containing 93 protein-coding genes. The stramenopiles were found to have branched out from the Chromista taxa (cryptophytes, haptophytes, and stramenopiles), while the cryptophytes and haptophytes were consistently grouped into sister relationships with high resolution.</p></div

Overview of the red algal plastid genomes.

<p>Linearized maps of the complete <i>T</i>. <i>amphioxeia</i> plastid genome is compared with those of other cryptophytes. Color-coded syntenic blocks are shown above each genome, and gene maps are shown below each genome. The syntenic blocks above the horizontal line are on the same strand, and those below the line are on the opposite strand. The horizontal bars inside of the syntenic blocks indicate sequence conservation. The block boundaries correspond to sites at which inversion events occurred. On the gene maps, the genes above the horizontal line are transcribed from left to right, and those below the horizontal line are transcribed from right to left. The rRNA operons are shown in red.</p

tRNA sequences present in the cryptophyte plastid genome.

<p>tRNA sequences present in the cryptophyte plastid genome.</p

Circular map of the plastid genome of the cryptophyte <i>Teleaulax amphioxeia</i>.

<p>All of the genes are transcribed in a clockwise direction. Note the dense gene arrangement and the single large intergenic region. The protein-coding genes and ribosomal RNA and transfer RNA genes are labeled inside or outside of the circle. The genes are color coded according to the functional categories listed in the index below the map.</p

Characteristics of the cryptophyte plastid genome analyzed in this study.

<p>Characteristics of the cryptophyte plastid genome analyzed in this study.</p

Phylogenetic tree of the cryptophyte plastids.

<p>(A) RAxML phylogeny constructed from a concatenate of 93 proteins (18,180 amino acids). The ML and MP bootstrap values are shown above or below the branches. (B) A simple overview of cryptophyte plastid gene synteny. (C) RAxML phylogeny constructed based on 93 protein-coding genes (56,569 nucleotides). The ML, MP and NJ bootstrap values are shown above or below the branches. The bold branches indicate strongly supported values (ML, MP, and NJ = 100%). The asterisks indicate supported values = 100%, and the dashes indicate values with < 50% support. The scale bar depicts the number of substitutions/site.</p