Longistylin A from Cajanus cajan (L.) Millsp. disturbs glycerophospholipid metabolism and cytokinin biosynthesis of Nocardia seriolae.

ETHNOPHARMACOLOGICAL RELEVANCE: Nocardiosis is an uncommon infectious disease that bears certain similarities to tuberculosis, with a continuous increase in its incidence and a poor prognosis. In traditional Chinese medicine, the leaves of Cajanus cajan (L.) Millsp. are employed to treat wounds, malaria, coughs, and abdominal pain. AIM OF THE STUDY: In this study, we investigated the effects and mechanisms of longistylin A (LGA), a natural stilbene isolated from C. cajan, as a potential antibiotic against nocardiosis. MATERIALS AND METHODS: LGA was isolated from the leaves of C. cajan and assessed using a minimum bactericidal concentration (MBC) determination against Nocardia seriolae. Multi-omics analysis encompassing genes, proteins, and metabolites was conducted to investigate the impact of LGA treatment on N. seriolae. Additionally, quantitative analysis of 40 cytokinins in N. seriolae mycelium was performed to assess the specific effects of LGA treatment on cytokinin levels. Cryo-scanning electron microscopy was utilized to examine morphological changes induced by LGA treatment, particularly in the presence of exogenous trans-zeatin-O-glucoside (tZOG). The therapeutic effect of LGA was investigated by feeding N. seriolae-infected largemouth bass. RESULTS: LGA exhibited significant efficacy against N. seriolae, with MBC value of 2.56 µg/mL. Multi-omics analysis revealed that LGA disrupted glycerophospholipid metabolism and hormone biosynthesis by notably reducing the expression of glycerol-3-phosphate dehydrogenase and calmodulin-like protein. Treatment with LGA markedly disrupted 12 distinct cytokinins in N. seriolae mycelium. Additionally, the addition of exogenous tZOG counteracted the inhibitory effects of LGA on filamentous growth, resulting in mycelial elongation and branching. Furthermore, LGA treatment improved the survival rate of largemouth bass infected with N. seriolae. CONCLUSIONS: We found for the first time that LGA from C. cajan exhibited significant efficacy against N. seriolae by interfering with glycerophospholipid metabolism and cytokinin biosynthesis.

Influence of Development and Dietary Phospholipid Content and Composition on Intestinal Transcriptome of Atlantic Salmon (Salmo salar).

The inclusion of intact phospholipids in the diet is essential during larval development and can improve culture performance of many fish species. The effects of supplementation of dietary phospholipid from marine (krill) or plant (soy lecithin) sources were investigated in Atlantic salmon, Salmo salar. First feeding fry were fed diets containing either krill oil or soybean lecithin supplying phospholipid at 2.6%, 3.2%, 3.6% and 4.2% of diet. Fish were sampled at ~ 2.5 g (~1,990°day post fertilization, dpf) and ~10 g (2,850°dpf). By comparison of the intestinal transcriptome in specifically chosen contrasts, it was determined that by 2,850°dpf fish possessed a profile that resembled that of mature and differentiated intestinal cell types with a number of changes specific to glycerophospholipid metabolism. It was previously shown that intact phospholipids and particularly phosphatidylcholine are essential during larval development and that this requirement is associated with the inability of enterocytes in young fry to endogenously synthesize sufficient phospholipid for the efficient export of dietary lipid. In the immature phase (~1,990°dpf), the dietary phospholipid content as well as its class composition impacted on several biochemical and morphological parameters including growth, but these differences were not associated with differences in intestinal transcriptomes. The results of this study have made an important contribution to our understanding of the mechanisms associated with lipid transport and phospholipid biosynthesis in early life stages of fish.

Relevance of dietary glycerophospholipids and sphingolipids to human health.

Glycerophospholipids and sphingolipids participate in a variety of indispensable metabolic, neurological, and intracellular signaling processes. In this didactic paper we review the biological roles of phospholipids and try to unravel the precise nature of their putative healthful activities. We conclude that the biological actions of phospholipids activities potentially be nutraceutically exploited in the adjunct therapy of widely diffused pathologies such as neurodegeneration or the metabolic syndrome. As phospholipids can be recovered from inexpensive sources such as food processing by-products, ad-hoc investigation is warranted.

Selenium deficiency alters the formation of eicosanoids and signal transduction in rat lymphocytes.

Previous reports have shown that selenium (Se) nutrition alters the lipoxygenase pathway and mitogenic responses in bovine lymphocytes. In order to further understand how Se may alter lymphocyte function, we examined the effects of Se nutrition on arachidonic acid (AA) metabolism and phospholipase D (PLD) activation. Lymphocytes were isolated from the lymph nodes of rats fed either Se-deficient diet (-Se) or Se-supplemented diet (+Se) for 12 weeks. Our results revealed that calcium ionophore A23187-stimulated lymphocytes derived from -Se rats produced significantly less prostaglandins (PGs) than those obtained from +Se rats. Phospholipase D (PLD) activation by 12-O-tetradecanoylphorbol-13-acetate (TPA) was significantly lower in lymphocytes obtained from -Se rats when compared to cells from +Se rats. Furthermore, the addition of PGE2, PGD2 or PGF2alpha to suspended lymphocytes from -Se rats significantly enhanced PLD activity. The effects of TPA and PGE2 on PLD activation were additive. However, the addition of PGE2 abolished the significant difference in PLD activation between -Se and +Se cells observed in response to TPA alone. Based on these results, we postulate that dietary Se status plays an important role in the regulation of AA metabolism that subsequently affects PLD activation.