多不饱和脂肪酸调控基因表达的分子机制的研究进展

本文综述了多不饱和脂肪酸 (PUFA) ,尤其是n 3系的PUFA ,可以降低脂肪酸以甘油三酯形式的沉积 ,同时促进脂肪酸氧化和葡萄糖合成糖原。其具体机制是PUFA通过激活过氧化物酶体活化增生因子受体α (PPARα)来控制氧化途径过程中的基因表达 ,而对脂肪合成途径中有关基因的抑制则是通过降低能传递胰岛素和碳水化合物信息的转录因子与DNA的亲和力和转录因子的核内丰度。尤其是PUFA抑制了类固醇调控单元结合蛋白 1 (SREBP 1 )的核内丰度和表达 ,降低了核因子Y (NF Y)、Spl和肝核因子 4(HNF 4)与DNA的亲和力     

哺乳动物肺发生的调控

哺乳动物肺的发育起始于从前肠内胚层发育而来的成对肺芽突起，它以分支形态发生和肺特异性细胞分化的遗传预定模式侵入周围的中胚层间质。呼吸上皮 分化很可能受复杂的细胞－细胞间相互作用的影响，并且受影响前肠组织中转录因子表达的自分泌、旁分泌和体液信号的影响。在肺形态发生和基因表达中，若干个转录因子家庭起关键作用，包括同源[异型]域蛋白甲状腺转录因子－1（TTF－1），翼状－螺旋家族成员肝细胞核因子－3β（HNF-3β）和GIi家族中的锌指转录因子。TGF－β诱导不同类型停滞细胞（包括肺上皮细胞）的生长的一批蛋白的表达，其中一些蛋白沉积于肺泡外基质中。     

乙酸和β－羟丁酸对体外培养牛肝细胞脂代谢部分关键酶表达的影响

本研究以体外原代培养的奶牛肝细胞为模型,添加不同浓度的乙酸（AcOH）和p羟丁酸（BHBA）,探讨其对奶牛肝细胞脂肪酸代谢关键酶基因表达的影响。添加不同浓度乙酸和β－羟丁酸,培养24h后,提取细胞总RNA。应用实时荧光定量PCR方法,检测脂代谢关键酶长链脂酰辅酶A合成酶1（ACSLl）、柠檬酸合成酶（CS）和乙酰辅酶A羧化酶α（ACCα）mRNA丰度的变化。结果显示,适当浓度的AcOH能够促进肝细胞脂肪酸活化及氧化途径关键酶ACSLl和CS的转录,而高浓度AcOH能够抑制脂肪酸从头合成途径关键酶ACCα的转录;高浓度BHBA能够抑制肝细胞ACSLl、CS和ACCα的转录。说明血液中适当浓度的AcOH能够促进肝脏脂肪酸氧化并抑制脂肪酸从头合成,高浓度BHBA能够抑制肝脏脂氧化和合成,影响乳脂前体物的供应,进而影响乳脂合成。     

Cbfal对成骨细胞调控作用的研究进展

核心结合因子α1（Cbfal），是成骨细胞发生和分化的特异性转录因子。Cbfal／p56能激活T细胞特异性基因表达，Cbfal／1357的超表达能诱导多潜能间充质干细胞向成骨细胞表型分化，并激活骨钙蛋白、Ⅰ型胶原蛋白、骨桥蛋白、骨唾液蛋白等成骨基因转录。Cbfal基因反义寡核苷酸则阻止OB分化和骨化形成，如果Cbfal基因缺失，将导致形成以破骨细胞、软骨细胞和软骨组织为主而缺乏成骨细胞的骨骼系统。骨形态发生蛋白、转移生长因子、肿瘤坏死因子α、成纤维细胞生长因子2、甲状旁腺激素、糖皮质激素地塞米松和1，25（OH）2D3等因子可上调或抑制Cbfal的表达，在骨的发育和组织钙化过程中起着重要的调节作用。     

siRNA特异性抑制犊牛原代肝细胞SREBP—1c基因的表达

固醇调节元件结合蛋白-1c（SREBP-1c）是脂肪合成基因的重要转录调节因子,又称脂肪细胞决定和分化因子1。SREBP-1c主要在动物肝脏和脂肪细胞中表达,是脂肪代谢中重要的核转录因子,它可以通过调节脂肪代谢相关酶基因的表达来调控动物体内的脂肪合成。本试验设计合成了SREBP—1c的siRNA,通过脂质体转染将siR...     

肿瘤坏死因子α在动物脂肪代谢中的作用

肿瘤坏死因子（ＴＮＦ－α)是人们发展的一种能调控脂肪代谢的活性蛋白质，近年来的研究发现，ＴＮＦ－α可抑制摄食，增加机体产热量，弱化葡萄糖转运蛋白（ＣＬＵＴ）基因的表达，降低脂蛋白脂酶（ＬＰＬ）的活性，降低葡萄糖的吸收量，减少机体脂肪的生成,诱导ob基因的表达，增加瘦蛋白（Ｌeptin）生成量，还会引起机体的胰岛素抗性，从而调节机体脂肪代谢和能量平衡，同时，ＴＮＦ－α在肥胖动物或人的脂肪组织中过量表达，也会给人和动物机体带来很多副作用。     

乙酸和β-羟丁酸对体外培养牛肝细胞脂代谢部分关键酶表达的影响

以体外原代培养的奶牛肝细胞为模型,添加不同浓度的乙酸（Aceticacid,AcOH）和β-羟丁酸（β-hydroxybu—tyrate,BHBA）共培养24h后,提取细胞总RNA。应用实时荧光定量PCR方法检测脂代谢关键酶长链脂酰辅酶A合成酶1（Long-chain acyl-CoA synthetase-1,ACSL1）、柠檬酸合成酶（Citrate synthase,CS）和乙酰辅酶A羧化酶α（Acetyl coenzyme A carboxylase α,ACCα）mRNA丰度的变化。结果显示,适当浓度的AcOH能够促进肝细胞脂肪酸活化及氧化途径关键酶ACSL1和CS的转录,而高浓度AcOH能够抑制脂肪酸从头合成途径关键酶ACCa的转录;高浓度BHBA能够抑制肝细胞ACSL1、CS和AcCα的转录。结果表明,血液中适当浓度的AcOH能够促进肝脏脂肪酸氧化并抑制脂肪酸从头合成,高浓度BHBA能够抑制肝脏脂氧化和合成,影响乳脂前体物的供应,进而影响乳脂合成。     

维生素E的功能与研究进展

维生素 E（ VE）又称生育酚或抗不育因子，它是具有α－生育酚生物活性的所有生育酚和生育三烯酚的总称。已知的 VE有 8种，不同 VE在结构上的区别，在于甲基数和两类维生素都存在α，β，γ，δ四种同分异构体，其中的α－生育酚活性最高，分布最广，最具代表性，但自然界天然 VE很容易氧化。市售的 VE是经过稳定化的 dl－α－生育酚醋酸酯。 VE作为动物必需的营养物质之一，在动物体内有多种功能： 　　1 VE与生物抗氧化作用 　　1.1 VE的最主要作用是生物抗氧化剂作用，保护不饱和脂肪酸（ PUFA），尤其是亚油酸免受自动氧化。…     

共激活因子PGC-1α的研究进展

共调节因子通过与特定转录因子结合进而调节下游靶基因的表达。该文综述了共激活因子PGC-1α的分子结构特征及表达模式,介绍了该因子在适应性产热、线粒体生物合成、肌肉类型转换、肝脏糖异生和脂肪酸氧化等生理调控方面的研究进展。     

日粮多不饱和脂肪酸水平对鸡肉品质的影响：脂质氧化

本试验评价提高日粮多不饱和脂肪酸（PUFA）和α-醋酸生育酚（α-TA）水平对经冷冻处理后生、熟鸡腿肉脂质氧化的影响。将192只1日龄母雏鸡随机分成16个处理组，PUFA添加量的4个水平（15、34、45、61g/kg），α-TA的4个水平（0、100、200、400mg/kg）。煮熟肉和煮熟冻肉的TBARS值分别高于生肉12和24倍。与生鲜肉和生冻肉相比，日粮添加PUFA及α-TA更加显著影响煮熟鲜肉和蒸煮冻肉的脂质氧化。随着生鲜肉中PUFA含量的增加，煮熟肉的脂质氧化呈线性提高。日粮中添加α-TA的水平由200增加到400mg/kg，对肉的氧化稳定性无影响。煮熟肉的TBARS值与生肉中α-生育酚含量的非线性关系表明，抗氧化剂的饱和程度会对α-生育酚产生影响。等式：Y＝X（11.88＋63.38e^-0.007z）是用来估算一定日粮PUFA含量（x）条件．确保某一特定TBARS值（Y）所需的最低日粮α-生育酚水平（Z）。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.