50～75日龄番鸭日粮限制性氨基酸水平研究

本试验旨在研究日粮不同赖氨酸粗蛋白质比例和蛋氨酸（含硫氨基酸）赖氨酸比例对50-75日龄番鸭生产性能、血清生化指标和肌肉品质的影响。试验选用1440只健康50日龄番鸭，随机分为9组，每组4个重复，每重复40只鸭，饲喂9种不同赖氨酸粗蛋白质比例（Lys／CP）（分别为5％、5．5％、6％）和蛋氨酸（含硫氨基酸）赖氨酸比例（Me（SAA）t／Lys）（分别为35％（75％）、40％（80％）、45％（85％））的玉米-豆粕型日粮。试验结束时，进行称重，每个重复挑选2只接近平均体重的番鸭进行采血和屠宰。结果显示：（1）Lys／CP对日均采食量（ADFI）、日均增重（ADG）影响显著，5％和5．5％组显著高于6％组（P〈0．05）；Met（SAA）／Lys为40％（80％）的组ADFI显著高于45％（85％）组，40％（80％）组ADG显著高于其他两组，而料肉比显著低于其他两组；②Lys／CP为5％的组血清尿酸和甘油三酯含量显著高于（P〈0．05）其他两组；Me（SAA）t／Lys对血清尿酸和甘油三酯含量影响不显著（P〉0．05）；日粮Lys／CP和Met（SAA）／Lys对血清甘油三酯含量存在交互作用；③日粮Lys／CP为5．5％的组胸肌干物质（DM）含量显著高于其他两组，粗蛋白质（CP）含量显著高于6％组；Met（SAA）／Lys为35％（75％）和40％（80％）的组胸肌CP含量显著高于45％（85％）组；日粮Lys／CP和Met（SAA）／Lys对胸肌DM和CP含量存在交互作用；④日粮Lys／CP为5．5％和6％的组腿肌DM含量显著高于5％组，5．5％组腿肌CP含量显著高于其他两组；Met（sAA）／Lys为40％（80％）和45％（85％）的组腿肌DM含量显著高于35％（75％）组；日粮Lys／CP和Met（SAA）／Lys对腿肌DM和CP含量存在交互作用。

遗传改良高赖氨酸、高油脂玉米以仔猪的营养价值

作了两个试验比较生长猪对遗传改良高赖氨酸、高油脂玉米（HLHOC；0．408％赖氨酸、6．21％脂肪，以饲喂时所含水分为基础）和高油脂玉米（HOC；0．289％赖氨酸、5．97％脂肪，以饲喂时所含水分为基础）的营养适量。试验1，在分期处理轮换设计消化试验中，采用4只装有回肠T型套管非同窝公猪。0．75％总赖氨酸日粮含8．5％酷蛋白和与试验玉米相同赖氨酸（0．025％）。试验2，在一个主要影响是玉米类型和日粮赖氨酸（0．80或1．15％可消化赖氨酸）的2×2因子试验中，采用100只隔离早期断奶环境培育的阉公猪（起始体重8．3kg、27日龄）估计5个玉米粕为基础的日粮。第5个日粮油添加0．23％L－盐酸赖氨酸（0．975％可消化氨酸）的含0．08％可消化赖氨酸的HOC日粮组成。试验结果表明在H2HOC中的赖氨酸同HOC中的赖氨酸一样有产，HLHOC可成功地用于猪日粮中。

用食酸假单胞菌DNA转化大肠杆菌菌株过量生产赖氨酸和蛋氨酸

食酸假单胞菌(Pseudomonas acidovorans)菌株能过量生产赖氨酸,并且含有对反馈抑制不敏感的门冬氨酸激酶。用带有该菌株 DNA 片段的质粒转化抗乙基硫氨酸且过量生产蛋氨酸的大肠杆菌(Escherichia coli)突变体,获得的转化子同时过量生产赖氨酸和蛋氨酸。

Transfer of Lysine-rich Protein Gene into Rice and Production of Fertile Transgenic Plants

Lysine-rich protein gene (lys) was cloned from Psophocarpus tetragonolobus (L.) DC. A plant expression plasmid was constructed and lys gene was under the control of maize ubiquitin promoter which is the highest efficient monocotyledon promoter. The plasmid was introduced into rice embryogenic calli by microprojectile bombardment. The regenerated fertile plants were obtained by effective selection for hygromycin B resistance. Genomic PCR and Southern blotting analyses showed that the lys gene has been integrated into rice genome. Simultaneously, the results of GUS histochemical assay demonstrated that gus report gene is also expressed in leaves, stems and roots of the transgenic rice plants. Data analysis showed that lysine content in most of the 11 transgenic plants is differently improved, and in one of them increased by 16.04%.

Effects of Lysine on the Expression of GHR mRNA in Sheep

[Objective] This study was to investgate the effects of lysine on the growth of sheep and its mechanism. [Method] Fifteen sheep about one-year old as experimental material were divided into three groups （group A, group B end group C）, into whose basal feed 0, 4 and 10 g h/sine were respectively added. After 28 d of feeding, the experimental sheep were all slaughtered for sampling; then total RNAs were extrac- ted from the samples and used to clone GHR and GAPDH genes via retrotrenscription for analyzing the expression abundance of GHR mRNA in Iongissimus dorsi muscle from different treatments. [Result] The expression of GHR mRNA in treatment B was significantly higher than that in treatment A（ P 〈0.01 ）, and significantly higher then that in treatment C （ P 〈0.05） ; while that in treatment C and treatment A was insignificantly different（ P 〉 0.05）. [ Conclusion] Addition of lysine into basal feed of sheep could dose-independently improve the expression of GHR gene in Iongissimus dorsi muscle.

Rapid Determination of Lysine Content in Maize Kernel by Amino-acid Analyzer

In this study, nine high-lysine maize kernels and two kernels of common maize hybrid were used as experiment materials, and quantitative determination of lysine contents in high-lysine maize kernels and common maize kernels was carried out using Hitachi L-8900 Automatic Amino-acid Analyzer, to know the effect of the Analyzer in distinguishing the lysine contents between common maize kernels and high-lysine maize kernels. The results showed that the lysine contents of high-lysine maize kernels were among 0.34%-0.42%, while of common maize kernels were a- mong 0.24%-0.25%, and the difference was significant. Compared with other tradi- tional methods, this method is rapid, simple, sensitive, highly reproductive and needs fewer maize kernels, thus it is applicable in maize breeding.

Advances in Toxicology of Nε-(carboxymethyl)-lysine(CML)

Advanced glycation end-products （AGEs） are products of non-enzymatic glycation of proteins, lipids or nucleic acids and other macromolecules. To be spe- cific, Nε-（carboxymethyl）-Iysine （CML） is one of the most important components of AGEs, which is wildly distributed in the body and can be formed in vivo or in food processing and heating processes. Previous studies have shown that CML is a ma- jor immunological epitope in AGEs and plays an important role in diabetes and its complications, as well as in the development and progression of aging. This review summarized recent advances in major source, toxicological hazard and control mea- sures of CML.

Nutritional Quality of the Maize Combinations with Mutant Gene opaque-2 (o2)

[Objective] This study aimed to investigate the action of mutant gene o2 and its effect on nutritional quality of different maize combinations. [Method] A total of 33 normal maize combinations from 18 inbred lines were compared with 33 combinations including gene o2 from the corresponding o2 near-isogenic lines （o2-NILs）, to study the effect of o2 gene introduction on maize grain quality. [Result] The contents of lysine, protein and oil in o2-NILs were greatly more than that of normal maize combinations. Except for lysine, contents of other 14 amino acids changed when o2 gene was introduced. Contents of aspartic acid, threonine, glycine, isoleucine, histidine, arginine and proline were improved; while contents of serine, glutamic acid, alanine, valine, leucine, tyrosine and phenylalanine were decreased. Correlation analysis showed that contents of aspartic acid, arginine and threonine had the highest correlation with lysine content. Protein and oil contents had higher correlation with lysine content （0.48 and 0.38）. Analysis of 33 o2-NILs revealed that the o2 combinations CAL58×Ji477and CA156×196 showed high comprehensive quality and high yield with greater development potential. [Conclusion] This study will provide theoretical and material basis for improving the quality of temperate maize germplasm by introducing o2 gene.

蛋氨酸羟基类似物异丙脂在密云地区奶牛场应用效果调查分析

笔者调查密云地区奶牛示范场泌乳牛日粮结构发现,泌乳牛日粮中赖氨酸与蛋氨酸的比例不平衡,为3.09∶1,与最新的CNCPS模型中理想赖蛋比2.7∶1存在差距,影响了可代谢蛋白(MP)的利用率,造成日粮中蛋白质浪费。于是笔者与密云区畜牧技术推广站对此问题进行了技术指导,通过在泌乳牛日粮中补充蛋氨酸羟基类似物异丙脂(HMBi)25g/头·d,使赖蛋比从3.09∶1变为2.78∶1(接近2.7∶1)。添加HMBi11周,对比分析添加HMBi前后的泌乳量、乳蛋白率、养殖效益等数据。结果显示,泌乳量在泌乳末期没有下降反而提高了0.16%,乳蛋白率提高了1.8%,增加饲料成本外收入约7万元/年,可有效利用日粮中的氨基酸,提高MP的利用率,避免了日粮中蛋白质的浪费,提高了泌乳量和乳蛋白率,增加了养殖收入,为HMBi在奶牛场中的推广应用提供依据。

Overexpression of lysine specific demethylase 1 predicts worse prognosis in primary hepatocellular carcinoma patients

AIM:To investigate the clinicopathological features and prognostic value of lysine specific demethylase 1(LSD1) in hepatocellular carcinoma(HCC).METHODS:We examined LSD1 expression in 60 paired liver cancer tissues and adjacent noncancerous tissues by quantitative real time polymerase chain reaction(qRT-PCR) and Western blotting.In addition,we analyzed LSD1 expression in 198 HCC samples by immunohistochemistry.The relationship between LSD1 expression,clinicopathological features and patient survival was investigated.RESULTS:Immunohistochemistry,Western blotting,and qRT-PCR consistently confirmed LSD1 overexpression in HCC tissues compared to adjacent non-neoplastic tissues(P < 0.01).Additionally,immunostaining showed more LSD1-positive cells in the higher tumor stage(T3-4) and tumor grade(G3) than in the lower tumor stage(T1-2,P < 0.001) and tumor grade(G1-2,P < 0.001),respectively.Moreover,HCC patients with high LSD1 expression had significantly lower 5-year overall survival rates(P < 0.001) and lower 5-year disease-free survival rates(P < 0.001),respectively.A Cox proportional hazards model further demonstrated that LSD1 over-expression was an independent predictor of poor prognosis for both 5-year disease-free survival [hazards ratio(HR) = 1.426,95%CI:0.672-2.146,P < 0.001] and 5-year overall survival(HR = 2.456,95%CI:1.234-3.932,P < 0.001) in HCC.CONCLUSION:Our data suggest for the first time that the overexpression of LSD1 protein in HCC tissues indicates tumor progression and predicts poor prognosis.

Lysine-specific Demethylase 1 Represses THP-1 Monocyte-to-macrophage Differentiation

Objective To investigate the role of lysine-specific demethylase 1 （LSD1） in the process of THP-1 monocyte-to-macrophage differentiation. Methods Quantitative reverse transcription-polymerase chain reaction （qRT-PCR） and Western blotting were performed to analyze the expression of LSD1 and interleukin-6 （IL-6） in THP-1 monocytes and THP-l-derived macrophages. Chromatin immunoprecipitation （ChiP） assay was applied to detect the occupancy of LSD1 and H3K4 methylation at IL-6 promoter during THP-1 monocyte-to-macrophage differentiation. IL-6 mRNA level and H3K4 methylation at IL-6 promoter were analyzed using qRT-PCR and ChiP assay in LSD 1 -knockdown THP- 1 cells treated with 12-O-tetradecanoylphorbol- 13-acetate （TPA） for 0 4, 8, 12, and 24 hours. Fluorescence activated flow cytometry was performed to reveal the percentage of macrophages differentiated from THP- 1 monocytes. Results The expression of LSD1 reduced during THP-1 monocyte-to-macrophage differentiation （P〈0.01）. LSD1 occupancy decreased and H3K4 methylation increased at IL-6 promoter during the differentiation. With knockdown of LSD1, H3K4 methylation at IL-6 promoter was found increased after TPA treatment at different times points （all P〈0.05, except 24 hours）. The percentage of macrophages increased significantly in theTHP-I cells with LSD1 knockdown （P〈0.05）. Conclusions LSD1 is repressed during the monocyte-to-macrophage differentiation of THP-1 cells. Suppression of LSD 1-mediated H3K4 demethylation may be required for THP-1 monocyte-to-macrophage differentiation.

Acidic domains differentially read histone H3 lysine 4 methylation status and are widely present in chromatin-associated proteins

Histone methylation is believed to provide binding sites for specific reader proteins, which translate histone code into biological function. Here we show that a family of acidic domain-containing proteins including nucleophosmin （NPM 1）, pp32, SET/TAF 113, nucleolin （NCL） and upstream binding factor （UBF） are novel H3K4me2-binding proteins. These proteins exhibit a unique pattern of interaction with methylated H3K4, as their binding is stimulated by H3K4me2 and inhibited by H3K4mel and H3K4me3. These proteins contain one or more acidic domains consisting mainly of aspartic and/or glutamic residues that are necessary for preferential binding of H3K4me2. Furthermore, we demonstrate that the acidic domain with sufficient length alone is capable of binding H3K4me2 in vitro and in vivo. NPM1, NCL and UBF require their acidic domains for association with and transcriptional activation ofrDNA genes. Interestingly, by defining acidic domain as a sequence with at least 20 acidic residues in 50 continuous amino acids, we identified 655 acidic domain-containing protein coding genes in the human genome and Gene Ontology （GO） analysis showed that many of the acidic domain proteins have chromatin-related functions. Our data suggest that acidic domain is a novel histone binding motif that can differentially read the status of H3K4 methylation and is broadly present in chromatin-associated proteins.

Zinc reverses glycine-dependent inactivation of NMDARs in cultured rat hippocampal neurons

In the presence of glutamate and co-agonists, e.g., glycine, the N-methyl-D-aspartate receptor （NMDAR） plays an important role in physiological and pathophysiological brain processes. Previous studies indicate glycine could inhibit NMDAR respons- es induced by high concentration of NMDA in hippocampal neurons. The mechanism underlying this inhibitory impact, how- ever, has been unclear. In this study, the whole-cell patch-clamp recording and Ca2＋ imaging with Fluo-3/AM under laser scanning confocal microscope were used to analyze the possible involvement of NMDAR subnnits in this effect. We found that the peak current of NMDARs and Ca2＋ influx induced by high concentration of NMDA were reduced by treatment of gly- cine （0.03-10 I.tmol L-1） in a dose-dependent manner, and that the glycine-dependent inhibition of NMDAR responses, which were induced at 300 mol L-1 NMDA, was reversed by ZnCI2 through the blocking of the NR2A subunit of NMDARs, but was less influenced by ifenprodil, a NR2B inhibitor. Our results suggest that the glycine-dependent inactivation of NMDARs is potentially modulated by the regulatory subunit NR2A.

Lysine residues K66, K109, and K110 in the bovine foamy virus transactivator protein are required for transactivation and viral replication

Bovine foamy virus(BFV) is a complex retrovirus that infects cattle. Like all retroviruses, BFV encodes a transactivator Tas protein(BTas) that increases gene transcription from viral promoters.BFV encodes two promoters that can interact with BTas, a conserved promoter in the 5' long terminal repeat(LTR) and a unique internal promoter(IP). Our previous study showed that BTas is acetylated by p300 at residues K66, K109, and K110, which markedly enhanced the ability of BTas to bind to DNA. However, whether these residues are important for BFV replication was not determined. Therefore, in this study we provide direct evidence that BTas is required for BFV replication and demonstrate that residues K66, K109, and K110 are critical for BTas function and BFV replication. Full-length infectious clones were generated, which were BTas deficient or contained lysine to arginine(K→R) mutations at position 66, 109, and/or 110. In vivo data indicated that K→R mutations at positions 66, 109, and 110 in BTas impaired transactivation of both the LTR and IP promoters. In addition, the K→R mutations in full-length infectious clones reduced expression of viral proteins, and the triple mutant and BTas deletion completely abrogated viral replication. Taken together, these results indicate that lysine residues at positions 66, 109, and 110 in the BTas protein are crucial for BFV replication and suggest a potential role for BTas acetylation in regulating the viral life cycle.