朗德鹅肝脏和脂肪组织LXRα基因表达水平的比较

采用荧光定量PCR技术检测了填饲和未填饲朗德鹅(landes anser)肝脏、腹脂、皮下脂肪组织和肌肉肝X受体α(LXRα)mRNA的表达水平,并与谷丙转氨酶等6种血清生化指标进行了相关性分析.结果发现,填饲组肝脏和腹脂组织LXRαmRNA表达水平显著高于对照组(P<0.05),高肝组皮下脂肪组织LXRα mRNA表达水平显著高于对照组和低肝组(P<0.05);肝脏组织LXRαmRNA表达水平与肝重/体重比呈显著正相关(P<0.05),相关系数为0.58,皮下脂肪组织LXRαmRNA表达水平与肝重/体重比呈极显著正相关(P<0.01),相关系数为0.77;肝脏LXRαmRNA表达水平与血清中甘油三酯和胆碱脂酶含量呈极显著正相关(P<0.01),相关系数分别是0.66和0.70.     

朗德鹅肝脏、脂肪组织LXRα基因表达水平的比较研究

本文采用荧光定量PCR技术检测了填饲、未填饲朗德鹅肝脏、腹脂、皮下脂肪组织和肌肉LXRα基因mRNA的表达水平，并与谷丙转氨酶等6种血清生化指标进行了相关性分析，结果发现：填饲组肝脏、腹脂组织LXRα基因mRNA表达水平显著高于对照组（P<0.05），高肝组皮下脂肪组织LXRα基因mRNA表达水平显著高于对照组、低肝组（P<0.05）；肝脏组织LXRα基因mRNA表达水平与肝重/体重比呈显著正相关（P<0.05），相关系数为0.58，皮下脂肪组织LXRα基因mRNA表达水平与肝重/体重比呈极显著正相关（P<0.01），相关系数为0.77；肝脏LXRα基因mRNA表达水平与血清中甘油三酯、胆碱脂酶含量呈极显著正相关（P<0.01），相关系数分别是0.66和0.70。     

朗德鹅3-羟基-3-甲基戊二酰辅酶A合酶基因(HMGCS1)cDNA克隆及其mRNA在填饲鹅肝组织中表达的研究

本实验旨在获得鹅(Anser anser)3-羟基-3-甲基戊二酰辅酶A合酶基因(HMGCS1)的cDNA序列,观察该基因的表达与填饲鹅肝脏生成胆固醇的相关性。选用填饲28 d朗德鹅作为实验材料,运用RACE方法扩增目的基因的cDNA序列,利用荧光定量PCR技术检测并分析HMGCS1基因在各组织中mRNA的表达,比较填饲28 d后各组织HMGCS1基因表达的变化,同时选用胆固醇试剂盒测定鹅肝中胆固醇的含量。结果显示,HMGCS1基因的cDNA全长为2 947 bp,开放阅读框编码522个氨基酸(GenBank登录号:KF425515)。荧光定量PCR结果显示,该基因在肝脏中表达显著高于其他组织(P0.05)。填饲28 d后,填饲组肝脏胆固醇含量低于对照组(P0.05),该基因在肝脏中的表达显著降低(P0.05)。氨基酸序列分析表明,HMGCS1基因高度保守,与鸭(Anas platyrhynchos)、鸡(Gallus gallus)、鸽子(Columba livia)等家禽同源性较高。该基因特异性地在肝组织中表达,且该基因的表达与肝脏中胆固醇合成呈正相关。本实验结果为进一步研究HMGCS1基因的功能提供了参考资料。     

鹅myf6基因的克隆,胚胎期以及填饲后表达特征分析

myf6基因属于MyoD家族成员之一,为成肌细胞分化成肌管的重要调控因子。本研究旨在克隆鹅(Anser anser)myf6基因,并进一步探讨该基因的结构与功能,揭示其在胚胎期和填饲后的表达特征。以鹅肌肉总RNA为模板,采用RACE的方法,克隆该基因全长cDNA序列,并进行生物信息学分析。运用实时荧光定量PCR检测myf6基因在鹅不同胚胎期mRNA的表达规律,以及填饲对其表达的影响。鹅myf6全长cDNA为1 196 bp,包括90 bp的5'UTR,383 bp的3'UTR和723 bp的开放阅读框(ORF),共编码240个氨基酸(GenBank登录号:JQ905627)。经预测鹅myf6编码蛋白的分子量为26 214.4,等电点为5.68,平均亲水性为-0.595,为不稳定亲水蛋白。预测鹅myf6蛋白具有Basic和HLH这两个明显的结构域,bHLH蛋白结构域形成剪刀状α-螺旋二聚体,且不同物种间HLH氨基酸序列高度同源。鹅myf6基因CDS区序列与鸭(Anas platyrhynchos)同源性最高,为98.62%,与哺乳类同源性在81%左右,与鱼类同源性较低,仅62%～66%。构建的系统进化树显示,所有哺乳类、鸟类、硬骨鱼各形成一个大的分支,两栖类形成独立分支,鹅首先与绿头鸭(Anas platyrhynchos)聚成一支,分子进化地位上关系最近,其次聚类顺序较近的物种为红原鸡(Gallus gallus),该结果与这些物种在生物学上的分类是较一致的。荧光定量PCR结果显示,鹅myf6 mRNA在胚胎早期第7天就有少量的表达,7天以后表达量逐渐上升,随后在胚胎中期表达量明显升高;其在E18肌肉组织中表达量达到高峰后下降,胚胎发育后期E21 myf6 mRNA的表达量是E25的近4倍,E25后逐渐趋于平稳;E18与E14、E15、E25和E28的表达差异极显著(P0.01),E21与E25、E28的表达也差异极显著(P0.01),与E14、E15的表达差异显著(P0.05)。在鹅的胸肌和腿肌组织中,填饲组myf6 mRNA表达量高于对照组中该基因的表达量,且胸肌组织达到显著水平(P0.05)。鹅myf6基因的表达具有组织特异性,该结果为进一步研究生肌调节因子myf6基因结构及其在鹅胚胎期肌肉发育中的作用提供了理论基础。     

填饲对朗德鹅SCD5、SREBP2和ELOVL6甲基化和mRNA表达的影响

DNA甲基化是表观遗传学的研究热点之一.为了探索填饲是否能够引起朗德鹅Anser anser)肝脏脂类代谢中DNA甲基化水平以及基因表达量的变化和DNA甲基化修饰作用和基因表达之间的关系.本研究运用焦磷酸测序技术分析鹅肝脏硬脂酞辅酶A去饱和酶5基因(stearovl-CoA desaturase 5,SCD5)、固醇调节元件结合蛋白2基因(sterol regulatory element-binding protein 2,SREBP2)和超长链脂肪酸延伸酶6基因(elongase of very long chain fatty acids 6,ELOVL6)的甲基化水平,再运用qRT-PCR技术进行定量验证.结果显示,SCD5、SREBP2和ELOVL6各2个片段的甲基化水平均在20％以上,均属于高甲基化状态;对照组3个基因各2个片段的甲基化水平均高于填饲组,填饲组与对照组的SCD5-1S和SREBP2-1S片段甲基化差异显著(P＜0.05),SREBP2-2S片段甲基化差异极显著(P＜0.01),SCD5-2S、ELOVL6-1S和ELOLV6-2S片段甲基化差异不显著(P＞0.05);填饲组SCD5和ELOVL6的mRNA表达量均高于对照组,而SREBP2在填饲组的mRNA表达量显著低于对照组(P＜0.05).综合各项指标,填饲引起鹅肝脏组织SCD5、SREBP2和ELOVL6甲基化水平降低,SCD5和ELOVL6 mRNA表达量上升,SREBP2的mRNA表达量降低,表明SCD5和ELOVL6的甲基化修饰对mRNA的表达起反向调控的作用.本实验结果为表观遗传学上DNA甲基化研究方法提供参考,为选育鹅肥肝高产高质系提供重要的分子遗传学依据,也为人类肥胖症和脂肪肝等代谢疾病的研究提供理论依据.     

猪黑素皮质激素受体-4基因(MC4R)启动子克隆及其分析

本研究旨在对猪黑素皮质激素受体-4基因(MC4R)的转录调控机制进行初步探讨.首先通过PCR方法扩增MC4R基因5’上游启动区l 234 bp(-1 264～-31 bp)的片段,再利用生物信息学方法对这一区域内潜在的转录起始位点进行了预测,最后采用步移缺失获得了11段长度不等的启动子片段,并分别克隆到荧光素酶(LUC)报告基因表达质粒(pGL3-Basic)中.同时,通过双荧光素酶报告活性分析检测MC4R基因启动子区不同长度片段在猪上皮型肾细胞(PK15)中瞬时转染后的活性.结果表明,猪MC4R 5’端-682 bp处存在1个潜在的转录起始位点(TSS),细胞检测结果显示-514～-486bp区域内存在控制MC4R基础转录活性的顺式调控元件,推测该序列内的热休克转录因子(HSF)结合位点可能对MC4R基因的表达调控及功能行使具有重要作用.     

绵羊脂肪细胞型脂肪酸结合蛋白基因(FABP4)cDNA的克隆、表达及其结构模拟分析

为探讨绵羊脂肪细胞型脂肪酸结合蛋白(FABP4)在不同生长阶段背最长肌中的表达特性,本实验以成年小尾寒羊(Ovis aries)皮下脂肪组织总RNA为实验材料,在脂肪细胞型脂肪酸结合蛋白基因(FABP4)cDNA保守区域设计1对引物Ff和Fr,采用RT-PCR方法克隆了绵羊FABP4全编码序列,并运用生物软件对FABP4蛋白空间结构进行分析.同时运用实时荧光定量PCR法,对FABP4在皮下脂肪和背最长肌中的表达以及不同日龄在背最长肌中的表达量与背最长肌肌内脂肪含量的相关性进行了初步研究.结果表明:绵羊FABP4基因cDNA长度为464bp,包含1个由399 bp组成的开放阅读框,编码132个氨基酸.生物信息学分析表明,不同物种间FABP4氨基酸序列具有较强的保守性,蛋白质空间结构呈2个α螺旋和10个β折叠围绕的桶状构型.实时荧光定量PCR试验表明,FABP4基因在160和200日龄绵羊背最长肌中的表达量明显高于90日龄背最长肌的表达量(P＜0.05);且在90、120、160和200日龄绵羊背最长肌中的表达量与相应日龄的背最长肌肌内脂肪含量呈正相关(R2=0.7196,P＜0.01).本研究结果表明,调控FABP4基因在背最长肌的表达是改善绵羊肉质的潜在途径.     

皖西白鹅肝脏中GHR，IGF-1和 IGF-1R基因的表达及与朗德鹅的比较

选择90日龄的皖西白鹅和朗德鹅各20只,取肝脏组织。采用半定量逆转录多聚酶链式反应（RT-PCR）的方法,以β-actin为内标,对肝脏组织中生长激素受体（GHR）、胰岛素样生长因子-1（IGF-1）、胰岛素样生长因子-1型受体（IGF-1R）的mRNA表达量分别进行比较分析,并分别与鹅的肝脏重及肝重率进行相关性分析。结果表明：皖西白鹅的肝脏重和肝重率都显著大于朗德鹅（p<0.05）;皖西白鹅肝脏中IGF-1的mRNA表达明显高于朗德鹅（p<0.01）;而GHR、IGF-1R mRNA在两品种间没有显著差异。体重与肝脏重显著正相关（r = 0.35,p<0.05）,肝重率与肝脏中IGF-1的mRNA的表达显著正相关（r = 0.67,p<0.01）,而与GHR、IGF-1R mRNA没有显著的相关性。结果提示：（1）90日龄的皖西白鹅肝脏生长优于朗德鹅;（2）两品种鹅肝脏生长的差异可能与肝脏中IGF-1 mRNA表达的差异有关。     

黑素皮质素受体3基因(MC3R)多态性及其单倍型组合与京海黄鸡屠体性状的关联分析

本研究旨在探讨黑素皮质素受体3基因(melanocortin 3 receptor,MC3R)对鸡(Gallus gallus)屠体性状的影响。采用聚合酶链式反应-单链构象多态性(polymerase chain reaction-single strand conformation polymorphism,PCR-SSCP)检测及测序的方法,检测MC3R在京海黄鸡群体中的单核苷酸多态性(single nucleotide polymorphisms,SNPs),并对这些多态位点进行连锁不平衡和单倍型分析。结果表明,在MC3R编码区序列(coding sequence,CDS)共检测到6个SNPs位点,各位点间均不存在强连锁不平衡;6个SNPs位点在379只京海黄鸡的群体中形成了5种单倍型和11种单倍型组合。最小二乘法分析结果表明,不同单倍型组合间京海黄鸡屠体性状(包括活体重、屠体重、胸肌重、腿肌重、全净膛重、半净膛重和腹脂重)存在显著或极显著差异(P<0.05或P<0.01),其中单倍型组合H3H4和H3H3的各种屠体性状均极显著高于单倍型组合H4H5(P<0.01),也显著高于其他部分单倍型组合(P<0.05),为屠体性状优势组合;单倍型组合H4H5各屠体性状均为最低,均显著或极显著低于其他大部分单倍型组合(P<0.05或P<0.01),为屠体性状劣势组合。因此,MC3R可能是影响鸡屠体性状的主效基因或与主效基因连锁,本研究为京海黄鸡屠体性状分子标记辅助选择提供了参考依据。     

Ermittlung der Gesamtsäuredeposition in nordrheinwestfälischen Fichten- und Buchenbeständen

Measurement of total acid deposition into spruce and beech forests in Northrhine-Westfalia During one year the deposition of H⁺, NH₄⁺, Al³⁺, Fe³⁺ and the acidity (BNC_8,2) in bulk precipitation and throughfall of spruce and beech stands was measured in Northrhine-Westfalia. It is shown that the calculation of acid deposition as the sum of the H⁺-equivalents of (H⁺ + NH₄⁺ + Al³⁺ + Fe³⁺ + Mn²⁺) underestimates total deposition of acidity. A simple and useful alternative is the calculation of H⁺-equivalents from (BNC_8,2 + 0.9 NH₄⁺ + Mn²⁺).     

Bemerkungen zur Ermittlung der ungesättigten Wasserleitfähigkeit unter nichtstationären Bedingungen

On the Determination of Capillary Conductivity at Unsteady-State Conditions . Therefore it is stated that for obtaining the effective k_u-values. Considering the importance of capillary conductivity for the soil water regime the large differences up to 2 orders of magnitude between determinations on core samples from the same soil using the double-membrane-method (Henseler and Renger 1969) and the evaporation-method (Becher 1971a) initiated a study concerning the error caused by a possible nonlinearity of suction changes between two measuring levels using the latter method. The study was carried out on disturbed and undisturbed core samples from the three textural classes sand, silt and clay and with modified evaporation method. Comparing the geometric means of the obtained k_u-values calculated at unsteady-state and quasisteady-state conditions for different suctions resulted in that with usual application of the method the measured k_u-values must be diminished for obtaining the effective k_u-values. This correction factor increased with suction and is considered to be more important in laboratory than in field use.

• 1 For sandy soils a correction factor of 2 at 150 cmH₂O increasing to 6 at 1000 cm H₂O must be applied. The coarser the sand would be, at the lower suction nonlinearity will start and the more rapidly the correction factor will increase;.
• 2 For silty soils a correction factor of 2–4 must be applied for suctions > 300 cm H₂O;.
• 3 For clayey soils a correction factor of 2 rapidly increasing to 10 must be applied for suctions > 150 cm H₂O, but depending on soil cracks.

. The overestimation of water through-put resulting from the uncorrected k_u-values amounts to 1.5–4.0 [l/m² · d] at 100 cm H₂O, but these values are within the variation of the effective k_u-values. For 800cm H₂O the overestimation amounts to 0.002–0.065 [l/m² · d], but this makes up 300–1000 % of the effective water through-put.     

Stärkegehalte von Kartoffelknollen in Abhängigkeit von Kalium-Ernährung und Knollenentwicklung

Starch content of potato tubers in relation to K nutrition and tuber growth In a pot experiment with potato (cv Saturna) K content in tubers increased from 1.0 to 2.6 % of tuber-DM due to increasing rates of K fertilizer. Simultaneously starch in tuber fresh matter decreased from 21 to 15 %. Highest starch content in tuber dry matter was obtained in that K treatment which gave the highest yield in dry tubers. Measuring starch accumulation during tuber growth revealed that already in the flowering stage differences exist in the starch contents of the tuber dry matter between the lowest and highest K treatments, namely 69 % for K₁ as compared with 64 % for K₅. The rate of starch accumulation between flowering and final harvest, however, was similar in all K treatments. This suggests that K supply affects the storage tissue at an early stage of tuber development probably via different water relations of tubers.     

Die Abschätzung von Nitratausträgen aus landwirtschaftlichen Nutzflächen mit Hilfe von Nmin-Daten

Development and application of a method for the estimation of nitrate leaching from agricultural land For two locations in the Rhine Valley in the State of Baden- Württemberg research on the nitrate leaching from agricultural fields was carried out. The investigated sites are located on aquifers that are pumped for drinking water. A new procedure was developed in order to estimate the nitrate losses by leaching from the rooting zone of agricultural fields. The procedure uses seepage estimates from a soil water simulation model and measured nitrate contents in the soil. It is found that for both sites large amounts of nitrate are washed out and that high nitrate concentrations occur in the seepage water. The simultaneous use of the investigated areas for intensive agriculture and for drinking water supply is questioned.     

Der Einfluß unterschiedlicher Kalium- und Nitraternährung auf pH-Änderungen in der Rhizosphäre

The Influence of potassium and nitrate nutrition on pH changes in the rhizosphere Seedlings of winter wheat, barley, sunflower, peanut and field bean were grown in soils differing in K and nitrate content. pH changes of the rhizosphere soil were measured periodically with antimony electrodes. In soils relatively poor in K the lowest pH values were measured at the root surface of the dicots (maximum pH decrease from 5 to 4.2), while soil pH increases from 5 to 5.4 in contact with roots of the monocots. Increasing K addition caused decreasing pH near peanut and field bean roots. In soils fertilized with K, monocot roots also decreased soil pH. In a K-rich soil the roots of the dicots decreased pH even after addition of 6.6 mg NO₃-N/100 g soil, while the roots of the monocots did not change pH. The pH changes are explained by an imbalance between anion and cation uptake, causing release of protons or hydroxyl ions. The reason for the differences in behaviour between monocots and dicots may be due to the differing cation-exchange capacity of the plant roots, causing a higher cation uptake by dicots and therefore greater proton release.     

Räumliche Variabilität der Phosphorgehalte im Oberboden landwirtschaftlich genutzter Flächen in kleinen Einzugsgebieten

Spatial variability of Phosphorus contents in topsoils of two small catchments under agricultural use The spatial variability of total phosphorus (P_t) contents was investigated in two small agriculturally used catchments in Saxony/Germany. The mean P_t concentration was 982 mg kg^–1, with 80 % of values between 560 and 1530 mg kg^–1. The largest P_t contents were found at the tops and foots of slope, and the smallest at the middle slope positions. At the scale of slopes (microscale) the spatial variability was caused by the relief and soil properties, whereas at the scale of catchments, agricultural management had the largest influence. These differences must be considered for the modeling of diffuse P inputs to surface waters.     

Schwefelausstattung ausgewählter europäischer Waldböden in Abhängigkeit vom atmogenen S-Eintrag

Sulfur status of selected European forest soils as dependent on the atmospheric S deposition Along a transect from the Pyrenees (SP), over the Vosges Mountains (FR), the Black Forest and the Bavarian Forest (D). and the eastern Ore Mountains to the Iser-Mountains (CR) 10 representative forest soil forms derived from granite regolith and 1 developed from gneiss debris (Dystric Cambisols, Leptic and Ferro-Humic Podzols) at montane and high-montane elevation were analyzed for their concentrations and amounts of total sulfur and various S fractions in order to study the impact of the atmospheric sulfur input, increasing from SW to NE, on the soil sulfur characteristics. Soils receiving low S inputs are generally characterized by low amounts of inorganic (especially water soluble) sulfate. Most of their total S amount consists of organic sulfur. With increasing S deposition, the concentrations of total S and C-S and the ratios S_t/C_org, C-S/C_org and SO₄?S_tor/C_org in the L-. Of- and Oh-horizons increase. The Aeh- and Ah-horizons of Cambisols and Podzols under different sulfur load do not differ with regard to the S parameters. The B horizons of the northeastern soils affected by high sulfur deposition, however, are markedly enriched with adsorbed and water-soluble sulfate and show comparably high ratios of sulfate S versus dithionite-extractable iron.