Comprehensive Screening for EPA/DHA-Structured Phospholipids in Aquatic Products by a Specific Precursor Ion Scanning-Based HILIC-MS/MS Method.

Comprehensive screening for functional substances from natural resources is always a hot research topic. Eicosapentaenoic acid- (EPA) and docosahexaenoic acid (DHA)-structured phospholipids (PLEPA/DHA) have versatile cardiovascular benefits as well as superior bioavailability. Herein, the abundance of PLEPA/DHA in 16 aquatic products was specifically and selectively screened using a recently developed precursor ion scan-driven hydrophilic interaction chromatography-mass spectrometry (PreIS-HILIC/MS) method with the fatty acyl moieties of EPA (m/z 301.6) and DHA (m/z 327.6) locked. The aim focused on the characteristics and differences in the varieties and contents of EPA/DHA-structured phosphatidylcholine (PCEPA/DHA) and EPA/DHA-structured phosphatidylethanolamine (PEEPA/DHA) molecular species. A total of 80 PLEPA/DHA molecules were identified in these natural sources, including 47 PCEPA/DHA and 33 PEEPA/DHA. After analysis, PC 16:0/20:5 and PC 16:0/22:6 are present in all aquatic products and at high levels. Antarctic krill was found to be the best resource of PLEPA/DHA in total (2574.69 µg·g-1), followed by mackerel (2330.11 µg·g-1), salmon (2109.91 µg·g-1), and Farrer's scallop (1883.59 µg·g-1), while abalone contained the lowest level of PLEPA/DHA (310.44 µg·g-1). Besides, sea cucumber and sea bass contained the highest contents of EPA-structured and DHA-structured ether phospholipids, respectively, which could be highly recommended as dietary sources of special functional phospholipids. Finally, the multiple discrepancies between the 16 aquatic products were revealed by multivariate statistical analysis. These findings improve the awareness of the composition and content of PLEPA/DHA contained in aquatic products, providing a reference for their integrated development.

Transcriptomics integrated with metabolomics reveals the ameliorating effect of mussel-derived plasmalogens on high-fat diet-induced hyperlipidemia in zebrafish.

Plasmalogens (Pls), a special group of phospholipids, are effective in ameliorating neurodegenerative disease. In the present study, the metabolic effects of seafood-derived Pls on high fat diet (HFD)-induced hyperlipidemia in zebrafish were evaluated, and the underlying mechanisms of dietary Pls against hyperlipidemia were explored through integrated analyses of hepatic transcriptomics and metabolomics. The results demonstrated that Pls supplementation could effectively alleviate HFD-induced obesity symptoms, such as body weight gain, and decrease total hepatic cholesterol and triglyceride levels. Integrated hepatic transcriptome and metabolome data suggested that Pls mainly altered lipid metabolism pathways (FA metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, and glycerolipid and glycerophospholipid metabolism) and the TCA cycle, induced the overexpression of anti-oxidation enzymes (Cat, Gpx4, Sod3a and Xdh), reduced disease biomarkers (such as glutarylcarnitine, gamma-glutamyltyrosine, and 11-prostaglandin f2) and gut microbiota-derived metabolites, and increased (±)12(13)-diHOME, EPA, lysoPC and PC levels. Moreover, 5 abnormally regulated metabolites were identified as potential biomarkers associated with hyperlipidemia according to the metabolomics results and suggested the involvement of gut microbiota in the anti-hyperlipidemic effects of Pls. Collectively, these findings suggest that the protective role of Pls is mainly associated with the promotion of unsaturated fatty acid biosynthesis and cholesterol efflux, lipid and phospholipid PUFA remodeling, and anti-oxidation and anti-inflammatory capabilities. This study provides valuable information for reasonably explaining the beneficial effects of seafood-derived Pls in alleviating hyperlipidemia and thus may contribute to the development and application of Pls as functional foods or dietary supplements to protect against obesity and hyperlipidemia.

[Nutrient uptake strategy selection by first-order roots of Juglans mandshurica under shading and phosphorus limitation]. / 遮阴和磷限制下胡桃楸1çº§æ ¹å »åˆ†å¸æ”¶ç­–ç•¥é€‰æ‹©.

We investigated root growth of 1-year-old Juglans mandshurica seedlings under different light environments and varying doses of phosphorus fertilizer, to understand the relationship between root resource acquisition strategies and the variations of light and phosphorus availability. There were four shading intensities (full light, 65% full light, 35% full light, and 20% full light) along with three doses of phosphate fertilizer (0 (CK), 200% soil background available phosphorus, and 500% soil background available phosphorus). We measured in root morphology characteristics, architectural characteristics, and mycorrhizal colonization rates of first-order roots. The results showed that average diameter, average root length, and mycorrhizal colonization rates of first-order roots gradually decreased, and the specific root length, specific surface area, branching ratio and branching intensity showed a trend of first increasing and then decreasing with the increases of shading degree. As the phosphorus content decreased, the first-order root diameter gradually became thinner, and the mycorrhizal infection rate gradually increased. Root morphology and architecture of J. mandshurica would undergo adaptive changes under shade, adapting to the shading environment by expanding specific root length, specific surface area, branching ratio and branching intensity. Under phosphorus limitation, root system of J. mandshurica would increase phosphorus absorption through symbiosis with mycorrhizal fungi. When J. mandshurica was artificially regenerate in forest land with a light transmittance of 35%, root morphology and architecture would adapt to the shading environment. The symbiosis between J. mandshurica and mycorrhizal fungi would be enhanced under phosphorus limitation, which could improve phosphorus absorption of roots.

Comparative transcript profiling of maize inbreds in response to long-term phosphorus deficiency stress.

Maize (Zea mays L.) is an important food and energy crop, and low phosphate (Pi) availability is one of the major constraints in maize production worldwide. Plants adapt suitably to acclimate to low Pi stress. However, the underlying molecular mechanism of Pi deficiency response is still unclear. In this study, comparative transcriptomic analyses were conducted to investigate the differences of transcriptional responses in two maize genotypes with different tolerances to low phosphorus (LP) stress. LP-tolerant genotype QXN233 maintained higher P and Pi levels in shoots than LP-sensitive genotype QXH0121 suffering from Pi deficiency at seedling stage. Moreover, the transcriptomic analysis identified a total of 1391 Pi-responsive genes differentially expressed between QXN233 and QXH0121 under LP stress. Among these genes, 468 (321 up- and 147 down-regulated) were identified in leaves, and 923 (626 up- and 297 down-regulated) were identified in roots. These Pi-responsive genes were involved in various metabolic pathways, the biosynthesis of secondary metabolites, ion transport, phytohormone regulation, and other adverse stress responses. Consistent with the differential tolerance to LP stress, five maize inorganic Pi transporter genes were more highly up-regulated in QXN233 than in QXH0121. Results provide important information to further study the changes in global gene expression between LP-tolerant and LP-sensitive maize genotypes and to understand the molecular mechanisms underlying maize's long-term response to Pi deficiency.

[Soil nutrient status of pure birch and larch plantations based on their seedlings bioassay].

One-year-old birch (Betula platyphylla) and larch (Larix olgensis) seedlings were respectively planted in pots with the soils taken from 35-year-old pure birch and larch plantations, and the seedlings growth, biomass increment, foliar nutrient content, and soil nutrient status were monitored, aimed to evaluate the fertility levels of the two soils and the possible interspecific interaction in mixed larch-birch forest. Birch soil had significantly higher contents of total N and available N than larch soil, while larch soil had significantly higher contents of total P, available P, and total K than birch soil (P < 0.05). In the first growth season, the height and collar diameter growth and the biomass accumulation of birch seedlings growing on birch soil were 69%, 52%, and 65% (P < 0.05) higher than those growing on larch soil, and the larch seedlings also had 12%, 8%, and 37% gains of the indices, respectively. The foliar N concentration of both larch and birch seedlings growing on birch soil was higher than that on larch soil, while the foliar P concentration was higher when the seedlings were growing on larch soil than on birch soil. The birch soil had higher content of available N because of the higher litterfall, while the larch soil had greater available P because of the higher P mobilizing effect. It was predicted that in mixed birch-larch forest, the complementary interaction of soil N and P could benefit the growth of the two tree species.

[Soil nutrient leaching patterns in maize field under different fertilizations: an in situ study].

An in situ field experiment with lysimeter was conducted to study the effects of different fertilizations on the nutrient leaching loss from brown soil in the growth season of summer maize. The results showed that abundant rainfall and irrigation were the main factors affecting the leaching loss. The leaching amount was higher in the early growth period of summer maize, but decreased after then. The difference among different fertilization treatments also decreased with maize growth. Comparing with N fertilization, wheat stalk plus N application intensified the leaching. During the growth period of summer maize, the NO3- -N content in leached water in fertilization treatments had two peaks, while the NH4+ -N content had a trend of increased first and decreased then. The leaching loss of soil N was mainly in the form of NO3- -N. The accumulative leaching loss of NO3- -N was 12.90-46.53 kg * hm(-2), and that of NH4+ -N was 1.66-5.11 kg x hm(-2), both of which increased with increasing N application rate. The leaching rate of soil N was 6.53%-13.07% higher in treatment wheat stalk plus N application than in treatments of N fertilization, and 3.66%-10.10% higher in low N treatments than in high N treatments. The accumulative leaching loss of available P was only 0.148-0.235 kg x hm(-2), while that of available K was 7.08-13.00 kg x hm(-2). In the late growth period of summer maize, wheat stalk plus N application increased the leaching loss of soil available P and K, while nitrogen application affected it slightly.