黄大茶水提物改善高脂小鼠脂肪组织的脂肪酸代谢

目的:探究黄大茶水提物对高脂饮食小鼠脂肪组织脂肪酸代谢的调控机制。方法:将5周龄雄性C57BL/6小鼠随机分为对照组、高脂饮食组、高脂饮食+2.5%(终质量分数,下同)黄大茶水提取物组、高脂饮食+0.5%黄大茶水提取物组。饮食干预处理12周后,测定小鼠体质量、脂肪组织质量,观察脂肪组织形态,并分析脂肪酸代谢关键基因及蛋白表达量等指标。结果:2.5%黄大茶水提物能高度显著降低高脂小鼠体质量及脂肪组织质量(P<0.001);减少脂肪组织的脂质沉积;促进SREBP-1C、FAS、ACC、SCD-1等脂肪酸生成相关基因的表达,促进脂肪酸分解相关基因PGC-1α和CPT-1的表达;不同程度激活腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)/乙酰辅酶A羧化酶(acetyl CoA-carboxylase,ACC)通路。结论:2.5%黄大茶水提物饮食干预能显著缓解高脂饮食小鼠肥胖和减少脂质沉积,促进脂肪组织脂肪酸合成和氧化分解代谢,此作用与黄大茶水提物激活AMPK/ACC通路相关。

ALPL缺陷加速高脂诱导小鼠肝内脂肪沉积

目的:明确肝/骨/肾型碱性磷酸酶基因(liver/bone/kidney alkaline phosphatase,ALPL)在高脂诱导肝内脂肪沉积的作用。方法:利用野生型(WT)和ALPL敲除小鼠(ALPL^(+/-)),给予高脂饮食8周诱导脂肪肝模型,检测小鼠肝内脂肪沉积和血清中葡糖糖、甘油三脂及胆固醇含量,并应用RT-PCR、Western blotting和免疫荧光染色检测肝组织中脂肪酸生成和转运相关基因表达变化。结果:ALPL^(+/-)组在正常饮食条件下较WT组肝内脂肪沉积无明显变化,而血清中葡萄糖和胆固醇含量增加;高脂条件下,敲除ALPL小鼠肝内脂肪沉积明显增加,且伴随血清中甘油三脂含量增加。RT-PCR和Western blotting结果显示,在高脂诱导下ALPL^(+/-)小鼠肝组织中关键脂肪酸生成基因ACC1、ACC2和PPAR-γ,及脂肪酸生成基因LPL表达明显增加。此外,免疫荧光染色结果显示高脂诱导下敲除ALPL小鼠肝组织中的PPAR-γ阳性肝细胞明显增加。结论:ALPL敲除促进肝内脂肪酸生成和转运,加速高脂诱导小鼠肝内脂肪沉积,为阐明脂肪肝病变分子机制提供理论支持。

Effects of Calanoid Copepod Schmackeria poplesia as a Live Food on the Growth, Survival and Fatty Acid Composition of Larvae and Juveniles of Japanese Flounder, Paralichthys olivaceus

Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for cul- turing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs （DHA, EPA and ARA） in S. po- plesia was significantly higher than that in the other two live foods （P〈O.O1）. Three live organisms were used for raising larvae and juveniles of Paralichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods （S. poplesia） had significantly higher growth rate than those fed with the other two organisms （P〈0.01）. The survival of the flounder larvae fed with copepods was significantly higher than that of the others （P〈0.01）, and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia （P〈0.05）. The contents of three types of HUFAs （DHA, EPA and ARA） and the ratio of DHA/EPA in larval and juve- nile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet orArtemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

Construction and characterization of a normalized cDNA library of Nannochloropsis oculata(Eustigmatophyceae)

We constructed and characterized a normalized cDNA library of Nannochloropsis oculata CS-179,and obtained 905 nonredundant sequences(NRSs) ranging from 431-1 756 bp in length.Among them,496 were very similar to nonredundant ones in the GenBank(E ≤1.0e-05),and 349 ESTs had significant hits with the clusters of eukaryotic orthologous groups(KOG).Bases G and/or C at the third position of codons of 14 amino acid residues suggested a strong bias in the conserved domain of 362 NRSs(>60%).We also identified the unigenes encoding phosphorus and nitrogen transporters,suggesting that N.oculata could efficiently transport and metabolize phosphorus and nitrogen,and recognized the unigenes that involved in biosynthesis and storage of both fatty acids and polyunsaturated fatty acids(PUFAs),which will facilitate the demonstration of eicosapentaenoic acid(EPA) biosynthesis pathway of N.oculata.In comparison with the original cDNA library,the normalized library significantly increased the efficiencies of random sequencing and rarely expressed genes discovering,and decreased the frequency of abundant gene sequences.

Development of Fatty Acid Biomarkers for the Identification of Wild and Aquacultured Sea Cucumber (Apostichopus japonicus)

In this study,the fatty acids(FAs) of the organs and tissues of sea cucumber(Apostichopus japonicus) were profiled in order to compare the FA composition of sea cucumber collected from natural habitat(wild) and cages(cultured).The differences in FA contents in dermomuscular tube,peripharyngeal annulus,gonad and intestine(with or without content) between the wild and the cultured were determined.The main fatty acids in all organs and tissues were 20:5n-3,16:1n-7,20:4n-6,22:6n-3,18:0,and 18:1n-7.The basically different FAs of body wall and digestive tube were 16:1n-7,18:1n-9 and 20:1n-11.The ratio of saturated to mono-and polyunsaturated FAs in digestive tube was independent on inside content while there was a redistribution of the total amount of n-3 and n-6 fatty acids.The comparison of FA composition of the wild and the cultured sea cucumber showed that 20:5n-3,16:1n-7 and 18:1n-7 predominated the wild while 20:4n-6 predominated the cultured.The content of branched-chain fatty acids in the wild was 3%–4% and about 9% in the cultured.The possible FAs for identifying the wild and the cultured sea cucumbers were selected.It was suggested that the indexes such as the ratio of either(n-3:n-6) to(n-7:n-6) or(n-3) +(n-7) to(n-6) may serve as the biomarkers distinguishing the wild and the cultured sea cucumber.

Effect of Altering Linoleic Acid and Linolenic Acid Dietary Ratios on the Performance and Tissue Fatty Acid Profiles of Prawn, Macrobrachium rosenbergii （de Man 1879） Post Larvae

A 90-day experiment was conducted to investigate the effects of different dietary linoleic acid （LA; 18：2n-6） and linolenic acid ratios （LNA; 18：3n-3） on growth induces, feed utilization and tissue fatty acid profile of freshwater prawn, Macrobrachium rosenbergii post-larvae （PL）. The experiment was conducted in cubic indoor fiberglass tanks, each holding 700 L in triplicate. Post-larvae with an average weight of 20.8 ± 0.20 mg were stocked at 80 PL m2. Five experimental isocaloric （15.06 MJ kgl digestible energy）, and isonitrogenous （30.45% digestible protein） diets were formulated by blending of soybean oil and linseed oil to containing five dietary LA/LNA ratios （7.80, 2.75, 1.28, 0.65 and 0.30）. The highest survival values were recorded for prawn PL fed diet containing 0.65 LA/LAN ratios. Growth indices of PL significantly increased （P 〈 0.05） with decreased dietary LA/LAN ratios to 0.65. The same trend was observed for the highest （P ≤ 0.05） protein efficiency ratio, protein productive value, fat retention, energy retention and best feed conversion ratio. The total whole tissue polyunsaturated fatty acid composition of M. rosenbergii PL was dominated by LA followed by LAN. Post larvae fed the diets containing higher LA/LNA ratios showed a higher tissue LA/LNA ratio. The obtained findings revealed that fatty acid patterns ofM. rosenbergii PL were influenced by fatty acid profiles of diets. The diet containing 0.65 LA/LNA ratio is recommended to obtaining optimum growth performance and feed utilization for M. rosenbergii PL.

Reproductive Cycle and Seasonal Variations in Lipid Content and Fatty Acid Composition in Gonad of the Cockle Fulvia mutica in Relation to Temperature and Food

From March 2004 to February 2005,seasonal variations in lipid content and fatty acid composition of gonad of the cockle Fulvia mutica(Reeve) were studied on the eastern coast of China in relation to the reproductive cycle and environment conditions(e.g.,temperature and food availability).Histological analysis as well as lipid and fatty acid analyses were performed on neutral and polar lipids of the gonad.Results showed that gametogenesis occurred in winter and spring at the expense of lipids previously accumulated in summer and autumn,whereas spawning occurred in summer(20.4-24.6℃).The seasonal variation in lipid content was similar to that of the mean oocyte diameter.In both neutral and polar lipids,the 20:5n-3 and 22:6n-3 levels were relatively higher than saturated fatty acids,and polyunsaturated fatty acids were abundant,with series n-3 as the predominant component.Seasonal variations in the 20:5n-3 and 22:6n-3 levels and the principal n-3 fatty acids were clearly related to the reproductive cycle.The ∑(n-3) and ∑(n-6) values were relatively high during January-May,and the associated unsaturation index was significantly higher than that in other months.The results suggest that fatty acids play an important role in the gametogenesis of F.mutica.

Responses in growth, lipid accumulation,and fatty acid composition of four oleaginous microalgae to different nitrogen sources and concentrations

Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production.

Optimization of Wax Esters Production from Palm Fatty Acid Distillate and Oleyl Alcohol over Amberlyst 15

Wax esters were derived from long chain fatty acids and long chain alcohols with chain length of 12 carbons or more. These compounds have many potential applications in cosmetics, pharmaceuticals and food industries. The present work focuses on the synthesis of wax esters using palm fatty acid distillate and oleyl alcohol catalyzed by Amberlyst 15. Response surface methodology （RSM） based on a five-level, three-variable central composite design （CCD） was used to evaluate the interactive effects of synthesis, of amount of Amberlyst 15 catalyst （21.6-38.4% w/w）, reaction time （18-102 min） and molar ratio （palm fatty acid distillate to oleyl alcohol, 1：1.16-1：2.84） on the percentage conversion of palm fatty acid distillate. The optimum conditions derived via RSM were： amount of catalyst 33% w/w, reaction time 95 minute and palm fatty acid to oleyl alcohol molar ratio 1：2.7. The actual experimental conversion was 81.52% under optimum condition, which compared well to the maximum predicted value of 80.50%. Analysis of the yield showed that at optimum condition, 80.54% wax esters were produced.

Benzene containing polyhydroxyalkanoates homo-and copolymers synthesized by genome edited Pseudomonas entomophila

Microbial synthesis of functional polymers has become increasingly important for industrial biotechnology. For the first time, it became possible to synthesize controllable composition of poly（3-hydroxyalkanoate） （P3HA） consisting of 3-hydroxydodec- anoate （3HDD） and phenyl group on the side-chain when chromosome of Pseudomonas entomophila was edited to weaken its t-oxidation. Cultured in the presence of 5-phenylvaleric acid （PVA）, the edited P. entomophila produced only homopolymer poly（3-hydroxy-5-phenylvalerate） or P（3HPhV）. While copolyesters P（3HPhV-co-3HDD） of 3-hydroxy-5-phenylvalerate （3HPhV） and 3-hydroxydodecanoate （3HDD） were synthesized when the strain was grown on mixtures of PVA and dodecanoic acid （DDA）. Compositions of 3HPhV in P（3HPhV-co-3HDD） were controllable ranging from 3% to 32% depending on DDDA/PVA ratios. Nuclear magnetic resonance （NMR） spectra clearly indicated that the polymers were homopolymer of P（3HPhV） and random copolymers of 3HPhV and 3HDD. Their mechanical and thermal properties varied dramatically de- pending on the monomer ratios. Our results demonstrated the possibility to produce tailor-made, novel functional PHA using the chromosome edited P. entomophila.