Phospholipid Fatty Acid Profiles of Chinese Red Soils with Varying Fertility Levels and Land Use Histories

Analysis of phospholipid fatty acids (PLFAs) was used to estimate the microbial community structures of eight Chinese red soils with different fertility levels and land use histories. The total amounts of PLFAs in the soils were significantly correlated with soil organic carbon, total nitrogen, microbial biomass C and basal respiration, indicating that total PLFA was closely related to fertility and sustainability in these highly weathered soils. Soils for the eroded wasteland were rich in Gram-positive species. When the eroded soils were planted with citrus trees, the soil microbial population had changed little in 4 years but took up to 8-12 years before it reached a significantly different population. Multivariate analysis of PLFAs demonstrated that land use history and plant cover type had a significant impact on microbial community structure. However, the difference of soil microbial community structure in the paddy field compared to other land uses was not larger than expected in this experiment.

Effect of copper on phospholipid fatty acid composition of microbial communities in two red soils

The phospholipid fatty acid （PLFA） composition was analyzed in two red soils experimentally contaminated with copper at different concentrations. The total amounts ofphospholipid fatty acids （PLFAs） in both red soils were significantly correlated with soil microbial biomass C and N, which decreased consistently with increasing levels of copper. The relative quantities of the PLFAs 17：0 （10 Me）, i16：0, il 5：0 and 16：1w5c, decreased with increasing heavy metal concentration, while those of cyl7：0, which is an indicator of gram-negative bacteria, increased. The Shannon index calculated from the PLFA data indicated that Cu addition in the red soils decreased the population diversity of soil microbial communities. Multivariate analysis of PLFA data demonstrated that high levels of Cu application had a significant impact on microbial community structure and there is a threshold metal concentration for PLFA composition. Comparatively higher toxic effect on microbial biomass and community structure were found in the red sandy soil than those in the red clayey soil. The differential effect of Cu addition on microbial communities in the two soils may be due to differences in soil texture and cation exchange capacity.

Using Phospholipid FattyAcid Technique toAnalysis the Rhizosphere Specific Microbial Community of Seven Hybrid Rice Cultivars

To analyze the intrinsic relationship between rhizosphere microbial community structure and variety of rice, the microbial community structures in rhizosphere of different hybrid rice cultivars were determined with phospholipid fatty acids （PLFA） analysis. Three series of new-breeding hybrid rice cultivars in China were tested in the experiment, Ilyouming 86 （II-32A/Minghui 86）, Ilyouhang 1 （II-32A/Hang 1）, and Ilyouhang 2 （II-32A/Hang 2） with H-32A as female parent, XinyouHK02 （XinA/HK02） and YiyouHK02 （YXA/HK02） with HK02 as male parent, Chuanyou 167 （ChuanxiangA/MR167） and 44you167 （Hunan44A/MR167） with MR167 as male parent. The results showed that the microbial community in rhizosphere of the hybrid rice comprised bacteria, fungi, actinomycetes, and protozoa, according to the 40 PLFA biomarkers detected. Bacteria were more abundant than fungi and actinomycetes in rhizosphere of the hybrid rice tested. Both sulfate-reducing and methane-oxidizing bacteria were found to exist in the hybrid rice rhizosphere. It was also found that the characteristics of PLFA biomarkers had correlation with the biological traits of rice. The cluster analysis suggested that microbial community structure and activity in rhizosphere were associated with genetic background of the rice cultivar.

Hatching egg polyunsaturated fatty acids and the broiler chick

Transgenerational effects of certain nutrients such as essential fatty acids are gaining increased attention in the field of human medicine and animal sciences as a new tool to improve health and animal performance during perinatal life.Omega-3(n-3)and omega-6(n-6)fatty acids are denoted by the position of the first double bond from methyl end of the hydrocarbon chain.Alpha-linolenic acid(18:3 n-3)and linoleic acid(18:2 n-6)are essential n-3 and n-6 fatty acids and cannot be synthesized by the vertebrates including chickens.Alpha-linolenic acid and linoleic acid are the parent fatty acids of long chain(>20–22C)n-3 and n-6 polyunsaturated fatty acids(PUFA)such as eicosapentaenoic acid(20:5 n-3,EPA),docosapentaenoic acid(22:5 n-3/or 22:5 n-6,DPA),docosahexaenoic acid(22:6 n-3,DHA)and arachidonic acid(20:4 n-6).As components of cell membrane phospholipids,PUFA serves as precursors of eicosa-noids,act as ligands for membrane receptors and transcription factors that regulate gene expression and are pivotal for normal chick growth and development.Considering the role of egg lipids as the sole source of essential fatty acids to the hatchling,dietary deficiencies or inadequate in ovo supply may have repercussions in tissue PUFA incorpora-tion,lipid metabolism,chick growth and development during pre and early post-hatch period.This review focus on studies showing how maternal dietary n-3 or n-6 fatty acids can lead to remodeling of long chain n-3 and n-6 PUFA in the hatching egg and progeny chick tissue phospholipid molecular species and its impact on chick growth and PUFA metabolism during early life.

Temperature-Dependent Fatty Acid Composition Change of Phospholipid in Steelhead Trout (Oncorhynchus mykiss) Tissues

In this study, the changes of the fatty acid composition of phospholipid in different tissues(muscle, heart, brain and spleen) of steelhead trout(Oncorhynchus mykiss) were analyzed when the water temperature decreased gradually from 16 to 12℃℃, 8℃, 6℃, 4℃, 2 and 1℃℃. Three fish individuals each tank(average weight 70.32 g ± 9.12 g) were collected and used to analysis at each designed temperatures. At normal temperature(16℃), the fatty acid composition of phospholipid of muscle and heart was similar each other. The highest concentration of saturate fatty acids(SFA) was found in the phospholipid of spleen. The brain phospholipid contained higher oleic acid(18:1 n9) than the phospholipid of other tissues at 16℃. When the environmental temperature decreased, the concentration of unsaturated fatty acids of phospholipids in all tissues increased, and accordingly the ratio pf the unsaturated to saturated fatty acids(U/S) and unsaturation index(UI) increased, indicating that steelhead trout can compensate temperature-dependent changes in membrane fluidity by remodeling the fatty acid composition of phospholipids. The changes in the fatty acid composition of phospholipid were tissue-specific. At the early stages of the experiment(16 to 8℃℃), the fatty acid composition of phospholipid changed remarkably in muscle, heart, and spleen. When temperature decreased to less than 8℃, an obvious response of phospholipid fatty acid was observed in all tissues. The change of phospholipid composition of steelhead trout tissues may be affected by both cold stress and starvation when the temperature decreased to 2℃, and the change of phospholipid composition of muscle was very obvious.

Optimization of High EPA Structured Phospholipids Synthesis from （u-3 Fatty Acid Enriched Oil and Soy Lecithin

The molecular structure of phospholipids can be changed enzymatically to obtain different tailor-made phospholipids. Incorporation of ω-3 fatty acids into phospholipids structure increased their oxidative stability, suggesting more health beneficial phospholipids. This study aimed to optimize eicosapentaenoic acid （EPA） incorporation into phospholipids structure by acidolysis reaction using free lipase （EC 3.1.1.3） from Rhizomucor miehei. Deoiled soy lecithin from anjasmoro variety was used as phospholipids source, while ω-3 fatty acid enriched oil was used as acyl source. Oil enriched with ω-3 fatty acids was obtained from low temperature solvent crystallization of lemuru （Sardinella longiceps） by-product. Response surface methodology （RSM） was used in this study to determine the relationship between the three factors （enzyme concentration, reaction time and substrate ratio） and their effects on EPA incorporation into soy lecithin structure. The results showed that the relation between EPA content with three factors （reaction time, enzyme concentration and substrate ratio） was quadratic. The significant factors were substrate ratio and reaction time. Optimum conditions at a ratio of 3.77：1 between ω-3 fatty acids enriched oil and soy lecithin, 30% lipase concentration, and 24.08 h reaction time, gave 22.81% of EPA content of structured phospholipids.

The effect of high fat food on erythrocyte phospholipids, fatty acids composition and glutathione redox-system of rats with alimentary dyslipidemia

To evaluate the effects of high fat food consisted of tallow (19% of total diets) and cholesterol (2%) on modification of erythrocyte phospholipids, fatty acids composition and glutathione redox- system of male Wistar rats with alimentary dysli- pidemia. The results demonstrated that after 30 and 180 days of high-fat feed erythrocyte phos- phatidylinositol and phosphatidylcholine levels were reduced, phosphatidylserine were in-creased. Only on the 90 days of the experiment phosphatidylinositol level increased. In all grow- ups the erythrocyte 18:0 saturated fatty acids and 20:4n6, 22:4n6 polyunsaturated fatty acids (PUFA) were increased. Deficit of n3 PUFA- 20:5n3 and 22:6n3 after 90 and 180 days high fat feed promoted compensatory synthesis from 18:1n9 on 20:3n9. Erythrocyte maleic dialde-hyde increased, glutathione level decreased in all groups of rats after fed with high-fat feed. Glutathione reductase and glutathione peroxi-dase activity decreased in erythrocytes after 30 and 180 days of high-fat feed. In conclusion: high-fat diet during 30-90 days started adaptive answer in lipids of membrane and glutathione redox-system. Important mechanism of adapta-tion of a cellular membrane to high-fat diet is increase major, structuring a membrane phos-phatidylethanolamine and minor, most meta-bolic significant fractions phospholipids (phos- phatidylinositol), keeps homeostasis of 18:2n6 and 22:6n3, 20:3n9 compensatory synthesis, decrease in activity of processes lipid peroxi-dation, activation of enzymes of redox-system glutathione. But prolonging the high-fat feeding (180 days and more) formed failure compensa-tory processes (dysadaptation). It is a risk factor of developmening atherosclerosis, diabetes, steatogepatitis and other diseases.

Effects of Dietary Phospholipids on Na^+-K^+-ATPase Activity and Cell Membrane Fatty Acid Composition in Gill of Catfish (Pangasius sutchi)

[ Objective] The aim of this study was to determine the effects of dietary phospholipids on Na＋ - K＋ - ATPase activity and cell mem- brane fatty acid composition in the gill of catfish （Pangasius sutchi）. [Method] 900 healthy catfish （1.4 ±0.08 g of average weight） were randomly divided into five groups. Dietary phospholipids level of group PL0 was 0%, and 1%, 2%, 3%, 4% for group PL1, PL2, PL3, PL4, respectively. The experiment lasted for 56 days. [Result] The results showed that the Na＋ -K＋ -ATPase activity in gill decreased gradually with the increase of the dietary phospholipids level （ P 〈0.05）. Cell membrane fatty acid composition was affected significantly by dietary phospholipids. The content of saturated fatty acids and monounsaturated fatty acids of group PLO was the highest （ P 〈 0.05）, however, it had the lowest content of highlyunsatu- rated fatty acids （ P 〈 0.05）. The content of polyunsaturated fatty acids of group 3 was higher than group 0 and group 1 （ P 〈 0.05）. E Conclusion] The results indicated that there is obvious compensation effects on Na＋ -K＋ -ATPase activity with phospholipids content changes in gills of catfish （ Pangasius sutchi） to maintain stable physiological level and normal basal metabolism and the increase of HUFA and ∑PUFA is necessary for gill cell membrane to better maintain and perform normal physiological function.

Olive and Corn Oil Enriched Diets Changed the Phospholipid Fatty Acid Composition in Mice Liver after One-Thirds Hepatectomy

We examined the effect of dietary fats on the kinetics of liver regeneration after one-third partial hepatectomy (PH) in male Balb/c mice. Corn and olive supplemented diets were chosen as a model of n-6 and n-9 diets. Phospholipid fatty acids were determined by gas chromatography (GC) after previous fractionation by solid-phase extraction using aminopropyl (NH2) column, and data were analysed by nonparametric Kruskal-Wallis test. Diet enriched with corn and olive oil did not affect the balance of lipid disorders during liver regeneration after 1/3 PH. Desaturases activity direction has changed depending on the used diet. The key role in the alteration of the polar fatty acids profile at all stages of liver regeneration and examined dietary fats is played by activity of stearoyl-CoA desaturase (SCD).

Plasma Phospholipid Omega-3 Fatty Acids and Freshwater Fish Consumption in the Brazilian Amazon

Background: Amazonian riverside communities consume large quantities of freshwater fish, comparable to marine fish consumption of Inuit, Scandinavian and Japanese populations. Few studies have considered the relation of high freshwater fish consumption and intake of omega-3 fatty acids (FA). Objective: The objective of the present study was to determine the profile of the concentrations of plasma phospholipid FAs and its relation with freshwater fish intake in 12 riverside communities in the Tapajós River basin (State of Pará, Brazilian Amazon). Design: This cross-sectional study included 333 adults (15 - 86 years old). Fish meal frequency was determined using a 7-day interview-administered dietary recall questionnaire. Fish were categorized as piscivorous and non-piscivorous fish on trophic level. Plasma phospholipid FAs were measured by capillary gas-liquid chromatography. Results: Participants consumed 5 to 6 fish meals a week, with twice as many non-piscivorous fish than piscivorous fish (4.4 fish/week vs 2.2 fish/week, respectively). The omega-3 FA levels in plasma phospholipids were low (EPA + DHA = 31.21 mg/L;%EPA + DHA = 2.59%). Omega-3 FAs increased with frequency of fish intake, and particularly with piscivorous fish, controlling for sociodemographic, anthropometric and lifestyle characteristics. DHA levels were greater in women than in men. Conclusions: Omega-3 FA in this Amazonian population increased with fish consumption, but although they consumed freshwater fish almost daily, the concentrations of omega-3 FA were relatively low and comparable to fish-eater communities for which fish is not a dietary mainstay. It is possible that nutrients present in marine, but not in certain freshwater fish species, may facilitate absorption of omega-3 FA. Sex and/or gender differences must be taken into account when assessing the relationship between fish consumption and plasma phospholipid omega-3 FA levels.

Comparison of the fatty acid composition of the serum phospholipids of controls, prediabetics and adults with type 2 diabetes

Objective: Although abnormalities in the fatty acid composition of serum and red cell membrane phospholipids of patients with type 2 diabetes are well-documented, lacking are studies of this issue in prediabetic individuals. Materials/Methods: For this cross-sectional study, we recruited 180 subjects (30 - 80 years), 56 of whom were normal with regard to glucose control (HbA1c, 6.5%). Serum phospholipids were isolated and analyzed for fatty acids. Results: Most importantly, the fatty acid compositions of the controls and prediabetic subjects were not different for 19 fatty acids. However, the fatty acid profile of the phospholipids of the patients with diabetes differed from the other two groups;the 14 to 18-carbon saturated fatty acids were decreased by 12% - 26% whereas the unsaturated fatty acids 16:1n-7, 18:1n-9, 18:2n-6, 20:3n-6 and 20:4n-6 were increased by 45% - 64%. Of note, the docosahexaenoic acid (DHA) status of individuals in all three study groups was remarkably low compared with international values, as indicated by DHA proportions in the 1.62% - 2.07% range, and there were no differences between groups. The mean melting point of the phospholipid fatty acids of the diabetic patients (32.2℃) was significantly lower (p < 0.001) than that of the prediabetic subjects (38.1℃) and the controls (39.9℃) which were not different from each other. Conclusion: These observations indicate that the fatty acid changes associated with type 2 diabetes follow the onset of the disease as opposed to being a causative factor of poor glucose control and insulin insensitivity.

Effects of Subcutaneous Fat Stores on Serum Phospholipids and Nonesterified Fatty Acid Lipid Fractions in Periparturient Dairy Cows

Negative energy balance in early lactating dairy cows results in a massive release of fatty acids （FA） into the blood in nonesterified fatty acids （NEFA） form. Large quantities of circulating NEFA may alter the serum FA profile of phospholipids （PL） fraction, which is responsible for cellular plasma membrane integrity and intercellular signaling. The objective of this study was to determine the effects of subcutaneous fat stores, as assessed by body condition score （BCS） on a scale of one to five, around the time of calving and the subsequent lipomobilization on FA profile of serum NEFA and PL lipid fractions, and on productive performance. Based on BCS, cows were retrospectively dichotomized into two groups： over-conditioned （BCS _〉 3.25） and control （BCS _〈 3.0）. 22 cows had serum samples obtained at -28, -7, 8, 18 and 28 d relative to parturition and analyzed for the FA profile of the NEFA and PL fractions. As expected, over-conditioned cows had greater total plasma NEFA concentrations and decreased dry matter intake. Milk yield and composition did not differ between groups. More importantly however, several FA in the NEFA fraction of plasma lipids varied significantly, including C14：1, C16：0, C18：0 and C20：3n3. In the PL fraction, other FA varied significantly by BCS around time of parturition, including C16：0, C17：0, total C18：2 cis, and C20：2. In summary, BCS did affect FA profile of serum NEFA and PL lipid fractions. This may have drastic consequences for circulating immune cells and their ability to fight infection by altering their FA profile.

利用磷脂脂肪酸(PLFAs)生物标记法分析水稻根际土壤微生物多样性

采用磷脂脂肪酸(PLFAs)生物标记法,分析了4个以Ⅱ-32A为母本和3个以制5为父本的系列杂交水稻组合在同等栽培条件下根际土壤的微生物群落结构,并探讨其与水稻特性的内在联系,以期为水稻育种和品种改良提供科学依据。结果表明,水稻根际土壤磷脂脂肪酸生物标记丰富,共检测到38种PLFAs,其中完全分布的生物标记有23种,不完全分布的有15种;水稻根际土壤中PLFAs含量细菌>真菌>放线菌。不同水稻材料根际土壤微生物磷脂脂肪酸生物标记组成结构存在差异。对根际土壤特征磷脂脂肪酸生物标记16:0(细菌)、18:1ω9c(真菌)、10Me17:0(放线菌)、10Me16:0(硫酸盐还原细菌)和16:1ω5c(甲烷氧化菌)比较可知,制5系列组合含量高,最高的为金生优制5,Ⅱ-32A系列组合较低,含量最低的为Ⅱ优797。对PLFAs总量和水稻特性进行Pearson相关分析,结果表明,PLFAs含量与水稻有效穗数和产量呈显著正相关,但与株高呈显著负相关。对水稻根际土壤磷脂脂肪酸生物量总量进行聚类分析发现,Ⅱ-32A系列组合聚为一类,制5系列组合聚为一类,表现出水稻遗传特性在其根际PLFAs上的差异性。研究结果表明,水稻根际土壤微生物群落PLFAs结构丰富,根际土壤微生物群落结构受水稻遗传亲缘关系的影响。

不同有机肥与化肥配施对植烟土壤微生物群落PLFAs和烤烟品质的影响

采用田间试验,在等氮、磷、钾施用量,有机氮占总施氮量25%的条件下,应用PLFAs方法,研究饼肥、鸡粪与化肥配施对植烟土壤微生物群落PLFAs和烤烟品质的影响。研究结果表明,各处理土壤中总PLFAs个数和各特征PLFA,如:16:00、18:1ω9c、10Me17:0、10Me 16:0、16:1ω5c、18:1ω7c等的相对生物量,均为配施有机肥的处理高于纯化肥处理(CK)。除甲烷氧化菌的特征PLFA 16:1ω5c含量是饼肥+化肥的处理大于鸡粪+化肥处理外,其它土壤微生物各特征PLFA的生物含量皆为鸡粪+化肥处理大于饼肥+化肥处理。结果还表明,与对照纯化肥相比,有机肥与化肥配施可提高烟株的抗病能力,提高烟叶中钾含量,降低烟叶氮含量,尤其是上部烟叶氮和烟碱的含量。饼肥、鸡粪与化肥配施,生产出的烟叶化学成分含量适中,可明显改善烟叶香气质,增加烟叶香气量,可提高上中等烟叶比例,增加烟叶产值。

柑橘黄龙病植株内生菌PLFAs多态性研究

采用磷脂脂肪酸(PLFAs)生物标记法,分析柑橘黄龙病株不同部位及健康状态叶片内生菌群落结构。结果表明,从柑橘黄龙病植株叶片共检测到42种PLFAs,其中完全分布的生物标记有9种,不完全标记有33种。对PLFAs进行聚类分析表明,柑橘黄龙病株不同部位叶片内生菌PLFAs可以分为2大类群,类群I特点为脂肪酸生物标记均为不完全分布,类群Ⅱ的特点为脂肪酸生物标记在被检测的柑橘黄龙病植株的大部分叶片中均有分布。柑橘黄龙病株不同部位及健康状态叶片内生菌PLFAs组成及含量存在差异。总体来看,不同朝向中,东面叶片内生菌PLFAs含量最大;不同高度中,下部叶片内生菌PLFAs含量最大;不同健康状态中,带有黄龙病原叶片内生菌PLFAs含量比健康植株叶片更大。此外,不同朝向中,南面叶片真菌/细菌值最大,革兰氏阳性菌和革兰氏阴性菌的比值(G+/G)较大;不同高度叶片中,真菌/细菌值差异不明显,G+/G值差异明显,上部最大,下部次之,中部最小;不同健康状态中,健康叶片的真菌/细菌值高于黄龙病株叶片。对柑橘黄龙病株不同部位及健康状态叶片内生菌多样性研究表明,不同朝向和不同健康状态的叶片内生菌种群多样性指数差异显著,不同高度的叶片内生菌种群多样性指数差异不显著。主成分分析表明,主成分1和主成分2基本上能把柑橘黄龙病株不同朝向叶片内生菌种群区分开来。对柑橘黄龙病株不同部位及健康状态叶片进行聚类,结果表明带有黄龙病原的叶片聚为一类,不带黄龙病原的健康叶片分聚为两类,其中,不同朝向的叶片分聚在不同的亚类群中,表明柑橘黄龙病株内生菌PLFAs分布与叶片健康状态和叶片朝向均有紧密关系,与叶片健康状态关系更为密切。

红花根际微生物群落磷脂脂肪酸(PLFAs)特征分析

【目的】研究新疆主栽品种红花根际微生物群落特征,探讨根际土壤微生物对品种响应的差异。【方法】采用磷脂脂肪酸(PLFAs)方法,检测红花根际土壤微生物PLFAs的种类及含量。【结果】在红花根际土壤中共检测到28种PLFAs,其中24种两个品种皆有分布,裕民无刺品种特有PLFAs为:15:1ω6c,a16:0,18:3ω6c(6,9,12),20:4ω6(9,12,15c);红花根际土壤中PLFAs含量细菌>真菌>放线菌;脂肪酸18:1ω9c(真菌)在两品种间差异显著。【结论】红花根际土壤微生物的磷脂脂肪酸生物标记种类和含量丰富,代表细菌的PLFA种类和数量最多,细菌在根际土壤中占优势;代表假单胞菌的PLFA(18:1ω7c)含量较高,可能与土壤中的固氮作用及解磷过程密切相关;红花品种间PLFA种类和含量存在一定差异。

杨桃与荔枝根区土壤微生物群落磷脂脂肪酸(PLFAs)特征分析

采用磷脂脂肪酸(PLFAs)方法,分析同一果园台湾软枝杨桃(20年树龄)和荔枝乌叶品种(15年树龄)根区土壤微生物群落结构。结果表明,从杨桃根区不同样品检测到25～32种微生物PLFAs,特有PLFAs为:i13:0,11:0 3OH,14:0 2OH;荔枝根区检测到23～40种微生物PLFAs,特有PLFAs为:16:0 3OH,i18:0,i12:0,12:1 AT11-12,a14:0。杨桃根区由PLFAs指示的土壤微生物多样性指数(Simpson)和特征脂肪酸16:0(细菌)、18:1ω9c(真菌)、10Me16:0(硫酸盐还原细菌)含量大小:距植株1.0 m土壤≈1.5 m土壤>0.5 m土壤;而荔枝根区Simpson指数和以上各种菌特征脂肪酸含量大小为:距植株1.0 m土壤>0.5 m土壤≈1.5 m土壤。脂肪酸10Me17:0(放线菌)和16:1ω5c(甲烷氧化菌)含量在杨桃根区无水平分布上的显著差异,而在荔枝根区则存在显著差异。

有机肥与化肥配施对烤烟土壤微生物群落PLFAs动态的影响

通过田间试验,应用PLFAs方法,并结合生物多样性指数测度法,研究有机肥与化肥配施对烤烟土壤微生物群落动态变化及一些特征PLFA生物标记含量的影响。研究结果表明:与纯化肥相比,有机肥与化肥配施可明显提高土壤微生物Shannon-Wiener(H)多样性指数、丰富度指数(S)和Pielou均匀度(J)及Simpson优势度指数(D),且25%鸡粪+化肥的处理优于25%饼肥+化肥的处理;在烤烟整个生长发育过程中,各处理土壤中总PLFAs和各特征PLFA,如:16:0、18:1w9c、17:010Me、16:010Me、16:1w5c和18:1w7c等的相对生物量,均在烤烟生长后期达到最高值;且配施有机肥的处理总是高于纯化肥处理(CK)。除甲烷氧化菌的特征PLFA16:1w5c含量是25%饼肥+化肥的处理大于25%鸡粪+化肥处理外,其它特征PLFA,如:硫酸还原细菌(SRB)PLFA16:010Me和厌氧细菌PLFA18:1w7c生物含量皆为25%鸡粪+化肥处理大于25%饼肥+化肥处理。

BDE-209对土壤微生物PLFAs特性的影响

采用室内模拟方法,分析了不同浓度BDE-209处理对土壤微生物磷脂脂肪酸(Phospholipid fatty acids,PLFAs)组成、含量、微生物群落结构和多样性的影响。结果表明,不同浓度BDE-209胁迫下土壤微生物包括内标19∶0在内,共检测出20种磷脂脂肪酸,土壤微生物群落PLFAs种类较丰富,PLFAs组成以饱和脂肪酸为主,其中脂肪酸16∶0含量最高,单不饱和脂肪酸、多不饱和脂肪酸、支链脂肪酸和环丙烷脂肪酸含量较少。不同浓度BDE-209会改变微生物的组成与含量,与对照(CK)相比,1.0 mg·kg-1处理可将不同种类PLFAs的增加或降低的程度分为3类,10 mg·kg-1和100 mg·kg-1处理的分为4类,增加程度最大的都是细菌。BDE-209对以PLFAs表征的土壤细菌、真菌、放线菌和总微生物量都有显著的影响,且真菌对BDE-209更敏感,细菌对BDE-209耐受更强,其中革兰氏阴性菌对BDE-209污染的响应较敏感,革兰氏阳性细菌更容易存活,而含16:1ω7t的微生物比含16:1ω7c的微生物抗逆性更强。主成分分析发现,对照、1.0、10 mg·kg-1处理和第一主成分呈显著正相关,100 mg·kg-1处理和第二主成分呈显著正相关,其中第一主成分以含16:0、18:0、18:1ω7t、18∶2ω6,9的微生物为优势种群,第二主成分以含i17:0、a15:0的微生物为优势种群。PLFAs表征的土壤微生物量和群落结构对BDE-209的响应敏感,可以作为BDE-209污染下指示土壤环境质量变化的有效生物指标。

Long-Term Effects of Docosahexaenoic Acid-Bound Phospholipids and the Combination of Docosahexaenoic Acid-Bound Triglyceride and Egg Yolk Phospholipid on Lipid Metabolism in Mice

The bioavailability of docosahexaenoic acid(DHA) and eicosapentaenoic acid(EPA) depends on their chemical forms. This study investigated the long-term effects of DHA-bound triglyceride(TG-DHA), DHA-bound phospholipid(PL-DHA), and the combination of TG-DHA and egg yolk phospholipid(Egg-PL) on lipid metabolism in mice fed with a high-fat diet(fat levels of 22.5%). Male C57BL/6J mice were fed with different formulations containing 0.5% DHA, including TG-DHA, PL-DHA, and the combination of TG-DHA and Egg-PL, for 6 weeks. Serum, hepatic, and cerebral lipid concentrations and the fatty acid compositions of the liver and brain were determined. The concentrations of serum total triglyceride(TG), total cholesterol(TC), high-density lipoprotein cholesterol(HDL-c), and hepatic TG in the PL-DHA group and the combination group were significantly lower than those in the high-fat(HF) group(P < 0.05). Atherogenic index(AI) of the PL-DHA group was significantly lower than that of the combination group(P < 0.05). Hepatic TC level in the combination group was significantly lower than that in the HF group(P < 0.05), but no significant difference was observed between the combination group and the PL-DHA group. Both the PL-DHA and the combination groups showed significantly increased DHA levels in the liver compared with the HF group(P < 0.05). However, there were no obvious increases in the cerebral DHA levels in all DHA diet groups. These results suggest that PL-DHA was superior to the combination of TG-DHA and Egg-PL in decreasing the AI. Long-term dietary supplementation with low amount of DHA(0.5%) may improve hepatic DHA levels, although cerebral DHA levels may not be enhanced.