New phenethylamine derivatives from Arenibacter nanhaiticus sp. nov. NH36A(T) and their antimicrobial activity

New Water-Soluble (Iminomethyl)benzenesulfonates Derived from Biogenic Amines for Potential Biological Applications

In this paper, a highly efficient and straightforward method for synthesizing novel Schiff bases was developed by reacting selected biogenic amines with sodium 2-formylbenzene sulfonate and sodium 3-formylbenzene sulfonate. 1H and 13C NMR, IR spectroscopy, and high-resolution mass spectrometry were used to characterize the new compounds. The main advantages of the proposed procedure include simple reagents and reactions carried out in water or methanol and at room temperature, which reduces time and energy. Moreover, it was shown that the obtained water-soluble Schiff bases are stable in aqueous solution for at least seven days. Additionally, the antioxidant and antimicrobial activity of synthesized Schiff bases were tested.

Synthesis, Molecular Docking, and Biological Evaluation of Novel Anthranilic Acid Hybrid and Its Diamides as Antispasmodics

The present article focuses on the synthesis and biological evaluation of a novel anthranilic acid hybrid and its diamides as antispasmodics. Methods: Due to the predicted in silico methods spasmolytic activity, we synthesized a hybrid molecule of anthranilic acid and 2-(3-chlorophenyl)ethylamine. The obtained hybrid was then applied in acylation with different acyl chlorides. Using in silico analysis, pharmacodynamic profiles of the compounds were predicted. A thorough biological evaluation of the compounds was conducted assessing their in vitro antimicrobial, cytotoxic, anti-inflammatory activity, and ex vivo spasmolytic activity. Density functional theory (DFT) calculation, including geometry optimization, molecular electrostatic potential (MEP) surface, and HOMO-LUMO analysis for the synthesized compounds was conducted using the B3LYP/6-311G(d,p) method to explore the electronic behavior, reactive regions, and stability and chemical reactivity of the compounds. Furthermore, molecular docking simulation along with viscosity measurement indicated that the newly synthesized compounds interact with DNA via groove binding mode. The obtained results from all the experiments demonstrate that the hybrid molecule and its diamides inherit spasmolytic, antimicrobial, and anti-inflammatory capabilities, making them excellent candidates for future medications.

Discovery and Biosynthesis of Antimicrobial Phenethylamine Alkaloids from the Marine Flavobacterium Tenacibaculum discolor sv11

The bacterial genus Tenacibaculum has been associated with various ecological roles in marine environments. Members of this genus can act, for example, as pathogens, predators, or episymbionts. However, natural products produced by these bacteria are still unknown. In the present work, we investigated a Tenacibaculum strain for the production of antimicrobial metabolites. Six new phenethylamine (PEA)-containing alkaloids, discolins A and B (1 and 2), dispyridine (3), dispyrrolopyridine A and B (4 and 5), and dispyrrole (6), were isolated from media produced by the predatory bacterium Tenacibaculum discolor sv11. Chemical structures were elucidated by analysis of spectroscopic data. Alkaloids 4 and 5 exhibited strong activity against Gram-positive Bacillus subtilis DSM10, Mycobacterium smegmatis ATCC607, Listeria monocytogenes DSM20600, and Staphylococcus aureus ATCC25923, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 4 μg/mL, and moderate activity against Candida albicans FH2173 and Aspergillus flavus ATCC9170. Compound 6 displayed moderate antibacterial activities against Gram-positive bacteria. Dispyrrolopyridine A (4) was active against efflux pump deficient Escherichia coli ATCC25922 ΔtolC, with an MIC value of 8 μg/mL, as well as against Caenorhabditis elegans N2 with an MIC value of 32 μg/mL. Other compounds were inactive against these microorganisms. The biosynthetic route toward discolins A and B (1 and 2) was investigated using in vivo and in vitro experiments. It comprises an enzymatic decarboxylation of phenylalanine to PEA catalyzed by DisA, followed by a nonenzymatic condensation to form the central imidazolium ring. This spontaneous formation of the imidazolium core was verified by means of a synthetic one-pot reaction using the respective building blocks. Six additional strains belonging to three Tenacibaculum species were able to produce discolins, and several DisA analogues were identified in various marine flavobacterial genera, suggesting the widespread presence of PEA-derived compounds in marine ecosystems.

Molecular Mechanism of Microbiota Metabolites in Preterm Birth: Pathological and Therapeutic Insights

Preterm birth (PTB) refers to the birth of infants before 37 weeks of gestation and is a challenging issue worldwide. Evidence reveals that PTB is a multifactorial dysregulation mediated by a complex molecular mechanism. Thus, a better understanding of the complex molecular mechanisms underlying PTB is a prerequisite to explore effective therapeutic approaches. During early pregnancy, various physiological and metabolic changes occur as a result of endocrine and immune metabolism. The microbiota controls the physiological and metabolic mechanism of the host homeostasis, and dysbiosis of maternal microbial homeostasis dysregulates the mechanistic of fetal developmental processes and directly affects the birth outcome. Accumulating evidence indicates that metabolic dysregulation in the maternal or fetal membranes stimulates the inflammatory cytokines, which may positively progress the PTB. Although labour is regarded as an inflammatory process, it is still unclear how microbial dysbiosis could regulate the molecular mechanism of PTB. In this review based on recent research, we focused on both the pathological and therapeutic contribution of microbiota-generated metabolites to PTB and the possible molecular mechanisms.

Biosynthesis and function of simple amides in Xenorhabdus doucetiae

Xenorhabdus doucetiae, the bacterial symbiont of the entomopathogenic nematode Steinernema diaprepesi produces several different fatty acid amides. Their biosynthesis has been studied using a combination of analysis of gene deletions and promoter exchanges in X. doucetiae and heterologous expression of candidate genes in E. coli. While a decarboxylase is required for the formation of all observed phenylethylamides and tryptamides, the acyltransferase XrdE encoded in the xenorhabdin biosynthesis gene cluster is responsible for the formation of short chain acyl amides. Additionally, new, long-chain and cytotoxic acyl amides were identified in X. doucetiae infected insects and when X. doucetiae was grown in Galleria Instant Broth (GIB). When the bioactivity of selected amides was tested, a quorum sensing modulating activity was observed for the short chain acyl amides against the two different quorum sensing systems from Chromobacterium and Janthinobacterium.

Arenibacter antarcticus sp. nov., isolated from marine sediment

A strictly aerobic, Gram-stain-negative, pale-golden, rod-shaped bacterium, designated as R18H21^T, was isolated from marine sediment collected from the Ross Sea, Antarctica. Strain R18H21^T grew at 4-40 °C (optimum 25 °C), at pH 6.3-9.2 (optimum 7.5-8.5) and in 0.5-6 % (w/v) NaCl (optimum 2 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain R18H21^T belonged to the genus Arenibacter, with the highest similarity to two type strains, Arenibacter latericius KMM 426^T (96.6 %) and Arenibacter certesii KMM 3941^T (96.6 %), and lower similarities (95.2-95.9 %) to five other members of the genus Arenibacter. The major fatty acids were iso-C17 : 0 3-OH, Summed Feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0, iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and an unidentified phospholipid. The respiratory quinone of strain R18H21^T was menaquinone-6. The DNA G+C content was 40.0 mol%. Based on phylogenetic, physiological and chemotaxonomic features, strain R18H21^T has been classified as a novel species in the genus Arenibacter, for which the name Arenibacterantarcticus sp. nov. is proposed. The type strain of the novel species is R18H21^T (=GDMCC 1.1159^T=KCTC 52924^T).

New Isocoumarins and Related Metabolites from Talaromyces flavus

Two new isocoumarin derivatives, talaisocoumarins A (1) and B (2), and three new related metabolites, talaflavuols A-C (3-5) were isolated from the wetland soil-derived fungus Talaromyces flavus BYD07-13. Their structures were elucidated by spectroscopic (NMR) and MS analyses. The absolute configurations of 1 and 2 were determined by CD and an Rh2(OCOCF3)4-induced CD method. All compounds were evaluated for cytotoxic and antimicrobial activities. However, none of them showed any activity. The plausible biosynthetic pathways for 1-5 were also proposed.