The quinone pigments of sea urchins, specifically echinochrome and spinochromes, are known for their effective antioxidant, antibacterial, antifungal, and antitumor activities. We developed in vitro technology for inducing pigment differentiation in cell culture. The intensification of the pigment differentiation was accompanied by a simultaneous decrease in cell proliferation. The number of pigment cells was two-fold higher in the cells cultivated in the coelomic fluids of injured sea urchins than in those intact. The possible roles of the specific components of the coelomic fluids in the pigment differentiation process and the quantitative measurement of the production of naphthoquinone pigments during cultivation were examined by MALDI and electrospray ionization mass spectrometry. Echinochrome A and spinochrome E were produced by the cultivated cells of the sand dollar Scaphechinus mirabilis in all tested media, while only spinochromes were found in the cultivated cells of another sea urchin, Strongylocentrotus intermedius. The expression of genes associated with the induction of pigment differentiation was increased in cells cultivated in the presence of shikimic acid, a precursor of naphthoquinone pigments. Our results should contribute to the development of new techniques in marine biotechnology, including the generation of cell cultures producing complex bioactive compounds with therapeutic potential.

This review presents literature data: the history of the discovery of quinoid compounds, their biosynthesis and biological activity. Special attention is paid to the description of the quinoid pigments of the sea urchins Scaphechinus mirabilis (from the family Scutellidae) and Strongylocentrotus intermedius (from the family Strongylocentrotidae). The marine environment is considered one of the most important sources of natural bioactive compounds with extremely rich biodiversity. Primary- and some secondary-mouthed animals contain very high concentrations of new biologically active substances, many of which are of significant potential interest for medical purposes. The quinone pigments are products of the secondary metabolism of marine animals, can have complex structures and become the basis for the development of new natural products in echinoids that are modulators of chemical interactions and possible active ingredients in medicinal preparations. More than 5000 chemical compounds with high pharmacological potential have been isolated and described from marine organisms. There are three well known ways of naphthoquinone biosynthesis—polyketide, shikimate and mevalonate. The polyketide pathway is the biosynthesis pathway of various quinones. The shikimate pathway is the main pathway in the biosynthesis of naphthoquinones. It should be noted that all quinoid compounds in plants and animals can be synthesized by various ways of biosynthesis.

One of the polyketide compounds, the naphthoquinone pigment echinochrome, is synthesized in sea urchin pigment cells. We analyzed polyketide synthase (pks) and sulfotransferase (sult) gene expression in embryos and larvae of the sea urchin Strongylocentrotus intermedius from various stages of development and in specific tissues of the adults. We observed the highest level of expression of the pks and sult genes at the gastrula stage. In unfertilized eggs, only trace amounts of the pks and sult transcripts were detected, whereas no transcripts of these genes were observed in spermatozoids. The addition of shikimic acid, a precursor of naphthoquinone pigments, to zygotes and embryos increased the expression of the pks and sult genes. Our findings, including the development of specific conditions to promote pigment cell differentiation of embryonic sea urchin cells in culture, represent a definitive study on the molecular signaling pathways that are involved in the biosynthesis of pigments during sea urchin development.

The genus Bizionia, a member of the Bacteroidota phylum, is considered a polyphyletic taxonomic group requiring a phylogenetic revision of its members. A novel strain 041-53-Ur-6^T was isolated from the cavity fluid of the sea urchin Strongylocentrotus intermedius from the Sea of Okhotsk. Analysis of the 16S rRNA gene sequence showed that 041-53-Ur-6^T belongs to the family Flavobacteriaceae, and its closest neighbor is [Bizionia] algoritergicola with 97.5% sequence similarity. Phylogenomic analysis confirmed the phylogenetic heterogeneity of the genus Bizionia and the clear separation of the genera “Algorimicrobium” and Hanstruepera. The inter-genus AAI values between them were 74.0–76.4%, which is slightly lower than the inter-species AAI values observed for each genus. The strain 041-53-Ur-6^T (= KMM 8389^T) formed a separated branch within the [B.] algoritergicola clade, demonstrating the highest ANI/AAI values of 80.1/81.0% with the strain [B.] algoritergicola APA-1^T. The dDDH values between strain KMM 8389^T and representatives of the genus “Algorimicrobium” ranged from 22.6% to 26.7%. Major fatty acids were iso-C_15:1 ω10c, iso-C_15:0 and iso-C_15:0 Δ2-OH. The polar lipids included a phosphatidylethanolamine, a phosphatidylglycerol, five unidentified lipids, two unidentified aminolipids, a phosphatidylcholine, and an unidentified aminophospholipid. The genome KMM 8389^T is a circular chromosome of 3,031,910 bp in size with a DNA G + C content of 33.5%. It comprises 2702 protein-coding genes and four rrn operons. Functional genomic analysis indicated the potential of KMM 8389^T for degrading starch, glycogen, and alginate due to the presence of genes encoding GH13, GH31, and GH65. Furthermore, KMM 8389^T possessed PLs 6, 7, 12, and 17, specialized for alginate, confirming the potential adaptation of this strain to algal substrates and surfaces. On the basis of the results of genotypic, chemotaxonomic, and phenotypic analyses, it is clear that the strain KMM 8389^T represents a novel species with [B.] algoritergicola, [B.] argentinensis, [B.] echini, [B.] hallyeonensis, [B.] myxarmorum, [B.] psychrotolerans, and [B.] sediminis as the nearest neighbors. These taxa are classified in a single novel genus, as Algorimicrobium algoritergicola gen. nov., comb. nov., A. argentinensis comb. nov., A. echini comb. nov., A. hallyeonensis comb. nov., A. myxarmorum comb. nov., A. psychrotolerans comb. nov., A. sediminis comb. nov., and Algorimicrobium bowmanii sp. nov. 041-53-Ur-6^T (=KMM 8389^T, =KCTC 72011^T).

The effect of methyl jasmonate and salicylic acid on the embryonic development of sea urchins Strongylocentrotus intermedius is studied. The extracts of naphthoquinoid pigments isolated from the embryos and larvae of individuals of S. intermedius after exposure to methyl jasmonate and salicylic acid have been qualitatively and quantitatively analyzed. The expression of polyketide synthase (pks) and sulfotransferase (sult) genes necessary for the biosynthesis of naphthoquinoid pigments in the embryos and larvae at the stages of mesenchymal blastula and gastrula of S. intermedius after incubation with methyl jasmonate and salicylic acid has been studied by the method of quantitative polymerase chain reaction in real time (qRT-PCR). The highest level of expression of the pks and sult genes in the treated embryos and larvae of S. intermedius has been observed at the blastula and gastrula stages.