Effects of fumaric acid supplementation on methane production and rumen fermentation in goats fed diets varying in forage and concentrate particle size

Background: In rumen fermentation, fumaric acid(FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.Methods: Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size(Fps:Cps), without or with FA supplementation(24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.Results: Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid(VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate(A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet(31.72%) than in the high-Fps:Cps diet(17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal p H. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps.Conclusions: Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.

Equilibrium of Extraction of Succinic, Malic, Maleic and Fumaric Acids with Trioctylamine

Extraction equilibrium features of succinic acid, malic acid,maleic acid and fumaric acid were investi- gated systematically withtrioctylamine (TOA) in chloroform, 4-methyl-2-pentanone (MIBK) and1-octanol. Fourier transform-infrared (FTIR) spectroscopic analysisof organic samples loaded with the acid shows that amine forms 1:1complex of ion-pair association with succinic acid, malic acid andmaleic acid, and 1:1, 2:1 complex of ion-pair association withfumaric acid. It is proposed that the complex forms depend on thesecond dissociation constant of the dibasic acid, pK_a2.

转基因Fah-/-肝损伤小鼠模型的构建

目的 建立转基因Fah-/-肝损伤小鼠模型,探讨其肝损伤的机制。方法 选取SPF级C57BL/6J野生型小鼠作为WT组。取转基因Fah+/-肝损伤杂合子小鼠培育后,根据基因鉴定结果选取6~8周龄的Fah-/-纯合子小鼠24只,分为正常给予NTBC饮水组、停NTBC饮水1周组和停NTBC饮水2周组,称量体质量,采血分离血清,进行肝功能生化指标检测,处死动物,取肝组织进行病理学检查、免疫组化检测Fah蛋白酶的表达及采用Western blot方法检测Fah蛋白表达。结果 经基因鉴定,成功繁育Fah-/-纯合子小鼠24只,后续用于肝损伤机制研究结果表明,停NTBC 1周组、停NTBC 2周组肝功能生化指标ALT、AST、TBIL与正常给予NTBC组比较显著升高,而ALB显著降低,差异有统计学意义。肝组织病理HE染色结果表明,WT组及正常给予NTBC组肝组织结构正常,而停NTBC组出现肝细胞肥大、坏死及炎性细胞浸润等不同程度的病变,停NTBC时间越长,肝损伤的程度越严重;肝组织免疫组化结果表明,WT组Fah蛋白酶表达为强阳性,正常给予NTBC组Fah蛋白酶表达阴性,停NTBC 1周组和停NTBC 2周组肝细胞Fah蛋白酶表达弱阳性。Fah蛋白表达结果与免疫组化结果基本符合。结论 成功建立Fah-/-小鼠模型并对其肝损伤机制研究,为后续研究提供实验数据参考。

Long-term and combined effects of N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide and fumaric acid on methane production,rumen fermentation, and lactation performance in dairy goats

Background:In recent years,nitrooxy compounds have been identified as promising inhibitors of methanogenesis in ruminants.However,when animals receive a nitrooxy compound,a high portion of the spared hydrogen is eructated as gas,which partly offsets the energy savings of CH4mitigation.The objective of the present study was to evaluate the long-term and combined effects of supplementation with N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide(NPD),a methanogenesis inhibitor,and fumaric acid(FUM),a hydrogen sink,on enteric CH4production,rumen fermentation,bacterial populations,apparent nutrient digestibility,and lactation performance of dairy goats.Results:Twenty-four primiparous dairy goats were used in a randomized complete block design with a 2×2factorial arrangement of treatments:supplementation without or with FUM(32 g/d)or NPD(0.5 g/d).All samples were collected every 3 weeks during a 12-week feeding experiment.Both FUM and NPD supplementation persistently inhibited CH4yield(L/kg DMI,by 18.8%and 18.1%,respectively)without negative influence on DMI or apparent nutrient digestibility.When supplemented in combination,no additive CH4suppression was observed.FUM showed greater responses in increasing the molar proportion of propionate when supplemented with NPD than supplemented alone(by 10.2%vs.4.4%).The rumen microbiota structure in the animals receiving FUM was different from that of the other animals,particularly changed the structure of phylum Firmicutes.Daily milk production and serum total antioxidant capacity were improved by NPD,but the contents of milk fat and protein were decreased,probably due to the bioactivity of absorbed NPD on body metabolism.Conclusions:Supplementing NPD and FUM in combination is a promising way to persistently inhibit CH4emissions with a higher rumen propionate proportion.However,the side effects of this nitrooxy compound on animals and its residues in animal products need further evaluation before it can be used as an animal feed additive.

益母草碱调节Fas/FasL信号通路对乳腺癌细胞恶性生物行为的影响

目的探讨益母草碱(Leonurine,Leo)对乳腺癌细胞的增殖、迁移、凋亡、细胞周期进展以及上皮间质转化的影响及作用机制。方法体外培养4T1乳腺癌细胞,将细胞分为对照组(Control组)、益母草碱低、中、高浓度组(Leo-L组、Leo-M组、Leo-H组)、益母草碱高浓度+转染短发夹RNA慢病毒阴性对照组(Leo-H+sh-NC组),益母草碱高浓度+转染Fas短发夹RNA慢病毒组(Leo-H+sh-Fas组)。使用不同浓度的益母草碱(10~160 mmol/L)处理细胞,CCK-8法检测细胞的存活率,筛选最佳实验浓度;通过Transwell小室法评价细胞的迁移能力;流式细胞术检测细胞凋亡率及细胞周期进展;Western blot检测N-cadherin、Vimentin、Fas、FasL表达,建立荷瘤小鼠模型评价益母草碱对乳腺癌移植瘤生长的影响。结果使用浓度为10~160 mmol/L的益母草碱处理细胞12 h,4T1细胞存活率显著降低(P<0.05),半数抑制浓度(IC50值)为(53.61±1.729)mmol/L,选择10、20、30 mmol/L为后续实验浓度;与Control组相比,Leo-L组、Leo-M组、Leo-H组4T1细胞的增殖活力、迁移率、G2/M期细胞比例及S期细胞比例、N-cadherin、Vimentin表达显著降低(P<0.05),细胞凋亡率、G0/G1期细胞比例、Fas、FasL表达显著升高(P<0.05);与Leo-H+sh-NC组相比,Leo-H+sh-Fas组4T1细胞的增殖活力、迁移率、G2/M期细胞比例及S期细胞比例、N-cadherin、Vimentin表达显著升高(P<0.05),细胞凋亡率、G0/G1期细胞比例、Fas、FasL表达显著降低(P<0.05);益母草碱可以抑制乳腺癌移植瘤的生长(P<0.05)。结论益母草碱可以抑制乳腺癌细胞恶性生物行为,其作用机制可能与激活Fas/FasL信号通路有关。

富里酸(FA)对微囊藻毒素-LR(MC-LR)的光降解作用及环境影响因素分析

为研究自然水环境中溶解性有机质(DOM)对微囊藻毒素-LR(MC-LR)的光降解作用,选择DOM的主要光敏活性组分富里酸(FA)作为光敏剂,在模拟太阳光照射下,对比了不同质量浓度FA(2.5、5.0、7.5、10.0 mg/L)溶液中MC-LR的光降解规律和光降解产物,并探究了不同pH、光照度对FA光降解MC-LR的影响。结果表明:MC-LR能在去离子水中发生直接光降解反应,不同质量浓度的FA对MC-LR的光降解均有促进作用,其中,7.5 mg/L FA对MC-LR的光降解作用最强,180 min时降解率达52.65%;FA对MC-LR的光降解过程符合二级反应动力学方程,其光降解产物与在去离子水中直接光降解的产物相同;不同pH和光照度下,FA对MC-LR的光降解作用依次为pH 6>pH 7>pH 8>pH 9,39.8μmol/(s·m^(2))>56.9μmol/(s·m^(2))>22.8μmol/(s·m^(2))。研究表明,pH和光照度均会影响FA对MC-LR的光降解作用,其中,pH为6、光照度为39.8μmol/(s·m^(2))时,FA对MC-LR光降解作用最强。

COMPARATIVE FATTY ACID COMPOSITION OF FOUR SARGASSUM SPECIES(FUCALES,PHAEOPHYTA)

Fatty acid composition of four Sargassum species from Qingdao and Shidao,Shandong Provincewas investigated.16:0（palmitic acid）was the major saturated fatty acid.C18 and C20were the mainpolyunsaturated fatty acids（PUFAs）.Arachidonic acid and eicosapentaenoic acid predominated amongpolyenoic acids in all the algal species examined.except for Sargassum sp.which had low concentrationof eicosapentaenoic acid.

The Effects of Dietary Fatty Acid Pattern on Layer's Performance and Egg Quality

The feeding trial was conducted to determine the effects of flaxseed on layer＇s performance and egg quality, and the effects of the dietary ratio of ω-6 fatty acid to ω-3 fatty acid on fatty acid deposition in yolk using flaxseed as resource of ω-3 fatty acid and sunflower seed as resource of ω-6 fatty acid. 192 20-wk-old Newroman commercial hens were randomly divided into 4 treatment groups with 6 replicates containing 8 birds. The rations corresponding with the four treatments were formulated with 4% flaxseed ＋ 9% sunflower seed, 8% flaxseed ＋ 18% sunflower seed, 15% flaxseed, and soybean meal, respectively. Sunflower seed was unshelled and flaxseed was whole. Ratios of ω-6 fatty acid to ω-3 fatty acid in 4 dietary treatments were 5.67, 5.21, 1.07, and 11.83, respectively. It can be concluded that long-term feeding 15% flaxseed had no significant （P〉 0.05） influence on egg production, egg weight, eggshell quality, yolk weight, and percentage of yolk weight. Dietary ratio of ω-6 fatty acid to ω-3 fatty acid had impact on the 0-3 fatty acid levels in yolk, nevertheless yolk fatty acid profiles were different from those of dietary fatty acid compositions.

Removal of Fulvic Acids from Aqueous Solutions via Surfactant Modified Zeolite

A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parameters, such as the loading level of HDTMA, the contact time, the initial FA concentration, the pH, and the types of the metal carious and organics were examined. The results show that SMZ with an HDTMA loading-level of 120% of the external cation exchange capacity（ECEC） of zeolite exhibits the best performance. Although the removal of fulvic acids by SMZ occurs rapidly within the first 30 min of the contact time, a contact time of at least 4 h is required to attain the adsorption equilibrium. The removal capacity of FA by SMZ decreases with the increase of the initial FA concentration. The pH has an effect on the FA removal efficiency because it can influence the characteristics of the FA molecules. The removal of FA is considerably enhanced by Ca^2＋ or Mg^2＋ ions and is adversely affected by phenol or pentachlorophenol（PCP）. Under the optimum conditions, 98% of FA could be removed by SMZ. Furthermore, the desorption of FA and the regeneration of SMZ were studied. The results show that a 30% ethanol solution is sufficient for the regeneration of SMZ.

Increased fatty acid synthase as a potential therapeutic target in multiple myeloma

Objective： To determine fatty acid synthase （FAS） expression in human multiple myeloma and verify its potential as a therapeutic target in multiple myeloma. Methods： FAS expression was determined by immunohistochemistry, reverse-transcription polymerase chain reaction （RT-PCR） and immunoblot analysis in bone marrow samples obtained from 27 patients with multiple myeloma （MM patients） and peripheral blood mononuclear cells （PBMCs） obtained from 12 healthy donors In parallel, additional analyses were performed on 2 human multiple myeloma cell lines, U266 and RPM18226. U266 cells were treated with cerulenin at various concentrations （5 to 320 μg/ml） for 24 h, and metabolic activity was measured by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assays. Apoptosis was evaluated by dual Annexin V/Pl （propidium iodide） labeling and flow cytometry （FCM） in U266 cells treated with 20 μg/ml cerulenin for 12 h or 24 h. Results： By immunohistochemistry, we found that 19 of 27 bone marrow samples obtained from MM patients expressed significantly high levels of FAS. Similarly, by RT-PCR, 22 of 27 bone marrow samples obtained from MM patients, U266 and RPM18226 showed FAS expression, whereas PBMC samples from 12 healthy donors did not express detectable level of FAS. FAS protein expression was confirmed by immunoblot analysis in 16 of 27 bone marrow samples obtained from MM patients, U266 and RPM18226 cell lines, and no FAS protein expression was detected in PBMC samples from 12 healthy donors. U266 cells were highly sensitive to cerulenin treatment, with a dosage-related effect on metabolic activity, as a measure for cell proliferation. U266 cells treated with 20 μg/ml cerulenin for 12 and 24 h also showed early sign of apoptosis with 56.9% and 69.3% Annexin V^＋/Pl cells, and late apoptotic and necrotic cells with 3.2% and 17.6% Annexin V^＋/Pl^＋ cells. Conclusion： Increased FAS expression existed in multiple myeloma samples and human myeloma cell lines. Cerulenin greatly inhibited metabolic activity/cell proliferation of U266 cells and induced apoptosis, suggesting that FAS is an effective target for pharmacological therapy in human multiple myeloma.

Effect of Retinoic Acid on Apoptosis and Expression of Fas Proteins in Mouse Blastocysts Cultured In Vitro

Mouse blastocysts were exposed to doses of 0, 1 and 10 μmol/L retinoic acid （RA） for 24 h and the cytotoxic effect of RA on the mouse blastocysts in vitro was observed. FITC-labeled terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL-FITC） assay was employed to stain apoptotic cells and immunohistochemical S-P staining method was used to detect the expression of Fas protein in mouse blastocysts in vitro. The results showed that RA could induce apoptosis and increase the expression of Fas proteins of trophectoderm （TE） and inner cell mass （ICM） cells in blastocysts. Compared with the findings for the control blastocysts, exposure to RA （10 μmol/L） resulted in a more significant apoptosis and higher expression level of Fas proteins （P〈0.01）. It was concluded that RA could induce apoptosis, which may result in a significant reduction in the average number of total cells and the trophectoderm/inner cell mass in blastocysts and an increased expression of Fas protein, suggesting that RA had a cytotoxic effect on the growth and development of early embryos in mice.

Analysis of fatty acid composition of sea cucumber Apostichopus japonicus using multivariate statistics

Fatty acids(FAs) provide energy and also can be used to trace trophic relationships among organisms.Sea cucumber Apostichopus japonicus goes into a state of aestivation during warm summer months.We examined fatty acid profiles in aestivated and non-aestivated A.japonicus using multivariate analyses(PERMANOVA,MDS,ANOSIM,and SIMPER).The results indicate that the fatty acid profiles of aestivated and non-aestivated sea cucumbers differed significantly.The FAs that were produced by bacteria and brown kelp contributed the most to the differences in the fatty acid composition of aestivated and nonaestivated sea cucumbers.Aestivated sea cucumbers may synthesize FAs from heterotrophic bacteria during early aestivation,and long chain FAs such as eicosapentaenoic(EPA) and docosahexaenoic acid(DHA) that produced from intestinal degradation,are digested during deep aestivation.Specific changes in the fatty acid composition of A.japonicus during aestivation needs more detailed study in the future.

六味降脂汤对NAFLD大鼠肝脏脂肪酸代谢及LXRα-SREBP-1c-FAS信号通路的影响

目的 探究六味降脂汤对非酒精性脂肪性肝病(NAFLD)大鼠的干预作用及其机制。方法 42只大鼠随机分为空白组、模型组、阿托伐他汀组(0.9 mg/kg)及六味降脂汤低、中、高剂量组(5.4、10.7、21.4 g/kg),给予高脂饲料合并高脂乳剂喂养6周建立NAFLD大鼠模型,造模成功后予相应药物干预2周后,检测血清ALT、AST、SOD活性及MDA、NEFA水平,检测肝组织TC、TG水平并计算肝脏指数,HE和油红O染色观察肝组织病理学改变,RT-qPCR和免疫组化(IHC)法检测肝组织LXRα、SREBP-1c、FAS mRNA和蛋白表达。结果 与空白组比较,模型组大鼠肝组织存在广泛较大的脂肪滴,脂肪变性明显,血清ALT、AST活性,MDA、NEFA水平及肝组织TC、TG水平,LXRα、SREBP-1c、FAS mRNA和蛋白表达均升高(P<0.01),肝组织SOD活性降低(P<0.01);与模型组比较,六味降脂汤各剂量组大鼠肝脏脂质沉积得到改善,脂肪变性程度减轻,血清ALT、AST活性,MDA、NEFA水平及肝组织TC、TG水平,LXRα、SREBP-1c、FAS mRNA和蛋白表达均降低(P<0.05,P<0.01),肝组织SOD活性升高(P<0.05,P<0.01)。结论 六味降脂汤具有调控肝脏脂肪酸代谢,减轻氧化应激反应,从而治疗NAFLD的作用,其潜在机制可能与抑制SREBP-1c-FAS信号通路有关。

改性松浦支渠疏浚底泥吸附重金属离子的研究

中国河流每年产生大量的疏浚底泥,大量堆积不仅占用土地资源,而且对环境还有很大的影响。底泥的二次利用显得尤为重要,基于以废制废的原则,提高底泥资源化利用的价值,以松花江松浦支渠疏浚底泥为目标,对其进行资源利用。首先以丙烯酸、富马酸为原料,以过硫酸铵为引发剂制备聚AA-FA,以磷酸氢二钠中和制得聚AA-FA磷酸盐。利用聚AA-FA磷酸盐对热解的疏浚底泥进行改性,制备得到聚AA-FA改性松浦支渠疏浚底泥。研究发现聚AA-FA改性松浦支渠疏浚底泥对于重金属离子具有较强的吸附作用。在添加量质量分数为9%时脱除离子的能力最高可达到99%,脱除不同离子的能力由大到小顺序为Ni^(2+)、Pb^(2+)、Cr^(3+)。

泥炭土腐殖酸环境室内模拟试验研究

为能提供一种贴合天然环境的泥炭土腐殖酸环境,通过在冲洪积黏性土中掺入胡敏酸(Humic Acid, HA)试剂和富里酸(Fulvic Acid, FA)试剂人工制备泥炭土试样,并将试样浸泡在富里酸液中来模拟泥炭土腐殖酸环境。采用腐殖酸含量检测试验、扫描电镜(Scanning Electron Microscope, SEM)、X射线衍射(X-Ray Diffraction, XRD)、X射线荧光光谱(X-Ray Fluorescence spectroscopy, XRF)和无侧限抗压强度(qu)试验来评估模拟效果及可行性。结果表明,在pH值为6.0的浸泡液中浸泡90 d后,试样中富里酸实测质量分数超过了初始掺量,而胡敏酸的实测质量分数相较于初始掺量表现出波动性。试样中孔隙随着腐殖酸掺量的增加而逐渐发育连通,试样所含的原生矿物主要为石英和云母,主要元素为O、Si、Al和Fe。通过与天然泥炭土环境对比分析,揭示了模拟的腐殖酸环境在微观特征上与天然腐殖酸环境具有相似性。宏观力学试验结果表明,模拟试样的qu随腐殖酸掺量的增加而降低,对比分析显示模拟试样的力学性能与天然泥炭土的力学性能接近。以上结果表明,采用所提出的方法可以模拟出与天然泥炭土环境相近的泥炭土腐殖酸环境。

三种代谢产物对老年急性心肌梗死患者发生肾损伤的预测价值

目的探讨老年急性心肌梗死(AMI)患者入院时血浆葡萄糖酸、富马酸和假尿苷联合预测急性肾损伤(AKI)的价值。方法收集2021年12月至2022年7月中国医学科学院阜外医院急诊科转入冠心病重症监护室治疗的老年AMI患者78例,根据住院期间AKI发生情况分为AKI组40例和非AKI组38例。采用液相色谱串联质谱定量分析AMI患者入院时血浆葡萄糖酸、富马酸和假尿苷水平。采用ROC曲线下面积(AUC)确定3种血浆代谢产物预测AMI患者发生AKI的价值。采用多因素logistic回归分析AKI的临床危险因素。结果AKI组与非AKI组血浆葡萄糖酸、富马酸和假尿苷水平比较,差异无统计学意义(P>0.05)。ROC曲线分析显示,葡萄糖酸、富马酸和假尿苷对老年AMI患者AKI发生无预测价值(AUC=0.576,95%CI:0.449~0.704,P=0.246;AUC=0.595,95%CI:0.467~0.721,P=0.154;AUC=0.563,95%CI:0.435~0.692,P=0.337)。多因素logistic回归分析显示,左心室射血分数(LVEF)是老年AMI患者发生AKI的独立预测因素(OR=0.923,95%CI:0.870~0.978,P=0.007)。结论老年AMI患者血浆葡萄糖酸、富马酸和假尿苷不能早期预测AKI发生,而LVEF是老年AMI患者发生AKI的独立预测因素。

填饲鹅肝脏组织中脂肪酸沉积与FAS基因mRNA的表达丰度

【目的】研究不同填饲期肥肝鹅肝脏组织中不同脂肪酸沉积与脂肪酸合成酶(fatty acid synthetase,FAS)基因mRNA的表达丰度及相关性。【方法】对200只100日龄青农灰鹅进行填饲,从填饲0 d起,每隔6 d屠宰1次,共6次。每次随机选取10只,每只为1个重复,屠宰测定肥肝重、肝中脂肪含量、各种脂肪酸含量和FAS基因mRNA的表达丰度。【结果】①肥肝重随填饲时间的延长而增加,肝中粗脂肪含量(ether extract,EE)随肝重的增加而增加,以填饲18—24 d鹅的肥肝增重最快(504.67 g/6 d),12—18 d的次之。②肝中饱和脂肪酸(saturated fatty acid,SFA)和单不饱和脂肪酸(monounsaturated fatty acid,MUFA)的含量随着填饲时间的延长而增加,尤其是在12—18和18—24 d这两个阶段的沉积最为明显,而多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)主要是在填饲后期(18—30 d)沉积;在整个填饲过程中,各种脂肪酸的沉积表现为填饲后期显著大于填饲前期(P<0.05或P<0.01);填饲30 d时沉积量较大的脂肪酸为肉豆蔻酸(C14﹕0)、棕榈酸(C16﹕0)、硬脂酸(C18﹕0)、棕榈油酸(C16﹕1)、油酸(C18﹕1)、二十碳烯酸(C20﹕1)和亚油酸(C18﹕2),每100 g组织中的含量分别为0.6028、17.72、7.25、2.75、37.42、0.3078和0.43 g。③FAS基因mRNA的表达丰度随肝脏增重和脂肪沉积速度的增加呈现出先增加后迅速降低的趋势,填饲24 d时极显著高于其它时期(P<0.01);0—24 d鹅肝脏组织中FAS基因mRNA表达丰度与肥肝重、EE、SFA和MUFA存在极显著正相关(P<0.01),而与PUFA存在弱负相关且差异不显著(P>0.05),30 d时相关性不显著(P>0.05)。【结论】①鹅肝中EE、SFA和MUFA的含量随填饲时间和肝重的增加而增加;填饲18—24 d鹅肝脏增重和EE、SFA和MUFA的沉积速度最快;②FAS基因mRNA的表达对肥肝鹅肝脏中脂肪的沉积具有填饲前、中期快速增加,填饲后期下降的调控作用。

动物脂肪酸合成酶(FAS)基因表达的调控

脂肪酸合成酶(FAS)催化乙酰辅酶A和丙二酸单酰辅酶A合成脂肪酸 ,从而在动物体脂沉积中发挥重要作用。动物体内脂肪酸合成酶受激素和日粮因素的调控。本文介绍了几种激素及日粮营养成分对脂肪酸合成酶的活性和基因表达调控的影响及其可能的作用机理 ,并就脂肪酸合成酶基因表达调控在实际生产中的应用进行了探讨。

电磁脉冲对小鼠脾细胞Fas和FasL mRNA表达的影响

目的 观察电磁脉冲对小鼠脾细胞 Fas和 Fas Lm RNA表达的影响 .方法 40只体质量 (18± 2 ) g的健康雄性 BAL B/c小鼠随机分为未照射组 (8只 )和全身照射组 (32只 ) .小鼠连续 2 d接受每日 2 5次脉冲的电磁脉冲全身照射 ,每次照射间隔约 2 min.于照射后 2 ,4,8和 12 h分别取 2只未照射小鼠和 8只照射小鼠的脾脏 .采用 RNA打点杂交法检测小鼠脾细胞 Fas和 Fas L RNA的表达水平 ,并对杂交信号进行灰度扫描后计算 RNA表达指数 .结果 受电磁脉冲照射后 2 h,小鼠脾细胞 Fas和 Fas L 的 RNA表达指数即分别从未照射的 0 .5 9± 0 .2 6和 0 .5 6± 0 .2 3升高到 0 .97± 0 .2 5和 0 .96± 0 .2 1,4h又下降至 0 .75± 0 .2 4和 0 .6 9± 0 .2 2 ,8h再度上升达最高峰 1.2 2± 0 .2 2和 1.32± 0 .5 0 (与对照组相比P<0 .0 0 1) ,于 12 h时下降至接近正常水平 .结论 电磁脉冲辐照可引起小鼠脾细胞 Fas和 Fas L RNA表达水平波动性升高 .

低叶酸和维甲酸诱导神经管畸形小鼠模型胎脑的转录物组学分析

神经管畸形(neural tube defects,NTDs)是一类中枢神经系统相关的重大出生缺陷型疾病。随着孕龄期妇女叶酸增补政策的推广,其发病率逐年下降致临床标本不易获取,因此,建立可靠的动物模型来研究NTDs的致病机制尤为重要。本研究分别通过低叶酸联合甲氨蝶呤(methotrexate,MTX)建立的诱导NTDs小鼠模型和维甲酸(retinoic acid,RA)诱导建立的NTDs小鼠模型,对NTDs胎鼠脑组织进行转录物组测序(transcriptome sequencing,RNA-seq)并分析差异表达谱,最后,通过实时荧光定量PCR(real-time quantitative polymerase chain reaction,RT-qPCR)进行结果验证。结果显示,低叶酸联合MTX诱导的胎鼠NTDs发生率为21.7%;RA诱导的胎鼠出现了强烈的致畸现象,畸形率为73.2%。相比正常胎鼠,低叶酸联合MTX诱导的NTDs小鼠组筛选出1443个差异表达基因(differentially expression genes,DEGs);RA诱导NTDs小鼠组筛选出3070个DEGs。对DEGs进行生物信息学分析,GO富集显示,上调基因主要参与前后轴发育、区域化和模式分化过程等生物学过程;KEGG富集显示,上调基因与心肌收缩、心肌病、神经活性配体-受体相互作用等信号通路相关。对2种模型鼠的DEGs进行Veen交集分析,结果显示,共有132个DEGs在2组模型中显著上调,其中包括Hox基因家族。通过RT-qPCR进行验证,发现与RNA-seq的结果一致。本研究对2种NTDs小鼠胎脑进行RNA-seq和差异表达谱分析,发现Hox的异常表达可能导致了NTDs的发生,为后续发病机制的研究提供了探索与思考。