Diabetes mellitus is one of the most serious diseases of our century. The drugs used are limited or have serious side effects. The search for new sources of compounds for effective treatment is relevant. Magnificamide, a peptide inhibitor of mammalian α-amylases, isolated from the venom of sea anemone Heteractis magnifica, can be used for the control of postprandial hyperglycemia in diabetes mellitus. Using the RACE approach, seven isoforms of magnificamide were detected in H. magnifica tentacles. The exon–intron structure of magnificamide genes was first established, and intron retention in the mature peptide-encoding region was revealed. Additionally, an α-amylase inhibitory domain was discovered in the mucins of some sea anemones. According to phylogenetics, sea anemones diverge into two groups depending on the presence of β-defensin-like α-amylase inhibitors and/or mucin-inhibitory domains. It is assumed that the intron retention phenomenon leads to additional diversity in the isoforms of inhibitors and allows for its neofunctionalization in sea anemone tentacles. Bioprospecting of sea anemones of the order Actiniaria for β-defensin-like α-amylase inhibitors revealed a diversity of inhibitory sequences that represents a starting point for the design of effective glucose-lowering drugs.

A Gram-negative, aerobic, rod-shaped, motile bacterium designated KMM 9957^T was isolated from a bottom sediment sample obtained from the Okhotsk Sea, Russia. Phylogenetic analyses based on the 16S rRNA gene and concatenated conserved protein-coding sequences positioned the novel strain KMM 9957^T in the genus Marinobacterium as a distinct line adjacent to Marinobacterium rhizophilum CL-YJ9^T, Marinobacterium profundum PAMC 27536^T, and Marinobacterium aestuarii KCTC 52193^T with 16S rRNA gene sequence similarities of 99%, 98.3%, and 98.2%, respectively. The average nucleotide identity and digital DNA–DNA hybridization values between strain KMM 9957^T and M. aestuarii KCTC 52193^T, M. profundum PAMC 27536^T, and M. rhizophilum DSM 18822^T were 89.4%, 87.9%, and 84.7% and 38.6%, 34.8%, and 28.4%, respectively. The genomic DNA G+C content of strain KMM 9957^T was 58.4 mol%. The dominant respiratory quinone was ubiquinone Q-8, and the major fatty acids were C_18:1, C_10:0 3-OH, C_16:0, and C_16:1ω7c. The polar lipids of strain KMM 9957^T consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, an unidentified aminophospholipid, two unidentified aminolipids, eight unidentified phospholipids, and three unidentified lipids. Based on the combination of phylogenetic and phenotypic characteristics, strain KMM 9957^T represents a novel species of the genus Marinobacterium, for which the name Marinobacterium sedimentorum sp. nov. is proposed.

A novel, strictly aerobic, non-motile, and pink-pigmented bacterium, designated 7Alg 153^T, was isolated from the Pacific green alga Cladophora stimpsonii. Strain 7Alg 153^T was able to grow at 4–32 °C in the presence of 1.5–4% NaCl and hydrolyze L-tyrosine, gelatin, aesculin, Tweens 20, 40, and 80 and urea, as well as produce catalase, oxidase, and nitrate reductase. The novel strain 7Alg 153^T showed the highest similarity of 96.75% with Pseudaestuariivita rosea H15^T, followed by Thalassobius litorarius MME-075^T (96.60%), Thalassobius mangrovi GS-10^T (96.53%), Tritonibacter litoralis SM1979^T (96.45%), and Marivita cryptomonadis CL-SK44^T (96.38%), indicating that it belongs to the family Roseobacteraceae, the order Rhodobacteales, the class Alphaproteobacteria, and the phylum Pseudomonadota. The respiratory ubiquinone was Q-10. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids, and one unidentified lipid. The predominant cellular fatty acids (>5%) were C_18:1 ω7c, C_16:0, C_18:0, and 11-methyl C_18:1 ω7c. The 7Alg 153^T genome is composed of a single circular chromosome of 3,786,800 bp and two circular plasmids of 53,157 bp and 37,459 bp, respectively. Pan-genome analysis showed that the 7Alg 153^T genome contains 33 genus-specific clusters spanning 92 genes. The COG20-annotated singletons were more often related to signal transduction mechanisms, cell membrane biogenesis, transcription, and transport, and the metabolism of amino acids. The complete photosynthetic gene cluster (PGC) for aerobic anoxygenic photosynthesis (AAP) was found on a 53 kb plasmid. Based on the phylogenetic evidence and phenotypic and chemotaxonomic characteristics, the novel isolate represents a novel genus and species within the family Roseobacteraceae, for which the name Algirhabdus cladophorae gen. nov., sp. nov. is proposed. The type strain is 7Alg 153^T (=KCTC 72606^T = KMM 6494^T).

C-type lectins (CTLs) are a family of carbohydrate-binding proteins that mediate multiple biological events, including adhesion between cells, the turnover of serum glycoproteins, and innate immune system reactions to prospective invaders. Here, we describe the cDNA cloning of lectin from the bivalve Glycymeris yessoensis (GYL), which encodes 161 amino acids and the C-type carbohydrate recognition domain (CRD) with EPN and WND motifs. The deduced amino acid sequence showed similarity to other CTLs. GYL is a glycoprotein containing two N-glycosylation sites per subunit. N-glycans are made up of xylose, mannose, D-glucosamine, 3-O-methylated galactose, D-quinovoses, and 3-O-methylated 6-deoxy-D-glucose. The potential CRD tertiary structure of the GYL adopted CTL-typical long-form double-loop structure and included three disulfide bridges at the bases of the loops. Additionally, when confirming the GYL sequence, eight isoforms of this lectin were identified. This fact indicates the presence of a multigene family of GYL-like C-type lectins in the bivalve G. yessoensis. Using the glycan microarray approach, natural carbohydrate ligands were established, and the glycotope for GYL was reconstructed as “Galβ1–4GlcNAcβ obligatory containing an additional fragment”, like a sulfate group or a methyl group of fucose or N-acetylgalactosamine residues.

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).

Thirteen new decaline polyketides, namely, zosteropenillines T–W (1–4), 8-hydroxypallidopenilline A (5), 13-epi-zosteropenilline P (6), 11-epi-zosteropenilline N (7), 15-hydroxyzosteropenilline M (8), 8-hydroxyzosteropenilline M (9), 11-epi-zosteropenilline M (10), and zosteropenillines X–Z (11–13), along with 17 known related compounds (14–30) were isolated from the ethyl acetate extract of the marine-derived fungus Penicillium yezoense KMM 4679 cultivated on MgCl₂-containing nutrient medium. The structures of the isolated compounds were established based on spectroscopic methods. The absolute configurations of zosteropenillines T (1) and V (3) were determined using time-dependent density functional theory (TD-DFT) calculations of the ECD spectra. X-ray diffraction analysis data were obtained for the known zosteropenilline S (28). A biogenetic pathway for 1–13 was proposed. The effects of the compounds on Staphylococcus aureus and Candida albicans growth and biofilm formation were observed. Zosteropenillines U (2), Y (12) and Z (13) with higher activity against C. albicans biofilms were nontoxic for normal cardiomyocyte H9c2 cells, making them promising anti-candidal agents. Moreover, zosteropenillines U and Y demonstrated cardioprotective effects in acute ischemia/reperfusion and CoCl₂-mimicking hypoxia in vitro models.