A single-nucleus transcriptomic atlas characterizes cell types and their molecular features in the ovary of adult Nile tilapia.

In fish species, there is limited analysis of signature transcriptome profiles at the single-cell level in gonadal cells. Here, the molecular signatures of distinct ovarian cell categories in adult Nile tilapia (Oreochromis niloticus) were analysed using single-nucleus RNA sequencing (snRNA-seq). We identified four cell types (oogonia, oocytes, granulosa cell, and thecal cell) based on their specifically expressed genes and biological functions. Similarly, we found some key pathways involved in ovarian development that may affect germline-somatic interactions. A cell-to-cell communication network between the distinct cell types was constructed. We found that the bidirectional communication is mandatory for the development of germ cells and somatic cells in fish ovaries, and the granulosa cells and thecal cells play a central regulating role in the cell network in fish ovary. Additionally, we identified some novel candidate marker genes for various types of ovarian cells and also validated them using in situ hybridization. Our work reveals an ovarian atlas at the cellular and molecular levels and contributes to providing insights into oogenesis and gonad development in fish.

A new flavonoid derivative and a new 5-hydroxyanthranilic acid derivative from the sea urchin-derived Streptomyces sp. HDa1.

One new flavonoid derivative flavoside A (1), one new 5-hydroxyanthranilic acid derivative crassilin (2), along with the known angucyclinone PD116740 (3) and oxachelin (4), was isolated from the EtOAc extract of the fermentation broth of the sea urchin (Anthocidaris crassispina)-derived actinobacterium, Streptomyces sp. HD01. The structures of these compounds were established on the basis of their HR-ESI-MS and NMR spectroscopic data. All of these compounds were assessed for their antibacterial activity.

Anthocidins A⁻D, New 5-Hydroxyanthranilic Acid Related Metabolites from the Sea Urchin-Associated Actinobacterium, Streptomyces sp. HDa1.

Four new 5-hydroxyanthranilic acid related compounds, named anthocidins A⁻D (1⁻4), two known analogues n-lauryl 5-hydroxyanthranilate (5) and isolauryl 5-hydroxyanthranilate (6), together with benzamide (7), 3-hydroxy-4-methoxycinnamamide (8), and (3S-cis)-hexahydro-3-[(3,4-dihydroxyphenyl)methyl]pyrrolo[1,2-a]pyrazine-1,4-dione (9), were isolated from the fermentation broth of the marine-derived actinomycete, Streptomyces sp. HDa1, which was isolated from the gut of a sea urchin, Anthocidaris crassispina, collected from Hainan Island, China. The structures of these secondary metabolites were elucidated on the basis of their 1D and 2D-NMR and mass spectroscopic data, and anthocidin A was confirmed by single-crystal X-ray diffraction with Cu Kα radiation. Anthocidins A⁻D (1⁻4) feature an acetyl group substitution at the amino group and varying alkyl side chains at the carboxyl group of 5-hydroxyanthranilic acid, and compound 5 was isolated as a natural product for the first time. The cytotoxic and antibacterial activity of compounds 1⁻9 were evaluated.

Spiculisporic acid analogues of the marine-derived fungus, Aspergillus candidus strain HDf2, and their antibacterial activity.

Two novel antibiotic spiculisporic acid analogues, named as spiculisporic acid F (1) and G (2), and two known compounds, (-)-spiculisporic acid (3) and secospiculisporic acid B (4), were isolated by bioactivity-guided fractionation from the fermentation broth of the sea urchin-derived Aspergillus candidus strain HDf2. Their structures were unambiguously established by comprehensive analysis of 1D and 2D NMR, and high-resolution MS spectra, and by comparison with known compounds. Biological experiments demonstrated that compounds 1 and 2 displayed antibacterial activity against Gram-negative Pseudomonas solanacearum and Gram-positive Staphylococcus aureus, but showed no cytotoxicity against SGC-7901 human gastric adenocarcinoma and SPC-A-1 human lung adenocarcinoma tumor cell lines. This is the first critical evidence identifying spiculisporic acid derivatives as a potential bio-control agent for the soil borne pathogen P. solanacearum (E. F. Smith) Smith. These findings provide further insight into the chemical and biological activity diversity of this class of compounds.

N-(Anthracen-9-ylmeth-yl)adamantan-1-amine.

In the crystal stucture of the of the title compound, C(25)H(27)N, stong π-π inter-actions are found between adjacent anthracene fragments, with a shortest centroid-centroid distance of 3.5750 (9) Å.

Streptoxamine, an unprecedented benzoisoindole-deferoxamine hybrid from the locust-derived Streptomyces sp. HKHCa2.

An unusual benzoisoindole-deferoxamine hybrid, streptoxamine (1), has been isolated from the ethyl acetate crude extract of the fermentation broth of a locust-associated actinomycete, Streptomyces sp. HKHCa2, which was isolated from an insect, Oxya chinensis. The structure of this secondary metabolite was elucidated on the basis of its one-dimension, two-dimension NMR, and mass spectroscopic data. This natural product features a hybrid pattern of a benzoisoindole with an "iron carrier" deferoxamine B through C-N linkage. Compound 1 showed weak antibacterial activity against the gram-positive bacteria, Staphylococcus aureus and Mycobacterium smegmatis.