合成氨基酸对肉鸡肠道功能的改善作用

鸡球虫病、坏死性肠炎等肠道感染可能对消化道内源性氨基酸损失产生较大影响。虽然对这一课题的了解不多，但相关文献报道了这些疾病对氨基酸表观回肠消化率的影响。在确定肠内氨基酸流动时必须考虑多种因素，包括肉鸡的年龄、是否有病原体、肠内氨基酸代谢等。胃肠道和肝脏共同承担向外周血释放氨基酸的任务，这些氨基酸是支持蛋白质合成所必需的。一般来说，肠道是氨基酸代谢反应的一个非常活跃的器官系统，它首先会满足自身对氨基酸的需求，然后才会将氨基酸输送到机体其他部分。因此，本综述旨在讨论影响肠内氨基酸流动的因素及日粮氨基酸和肠道感染对氨基酸利用和代谢的影响。     

滞绿突变对大豆叶片蔗糖代谢相关基因表达的影响

为研究大豆滞绿突变对叶片衰老过程中蔗糖代谢相关基因表达产生的影响，以晋大滞绿1号及其亲本晋大74号为试验材料，测定了大豆开花后至成熟期间叶片可溶性糖含量的变化趋势，并对比了不同基因型大豆品种叶片衰老过程中蔗糖代谢相关基因的表达差异。结果表明:1)花后至成熟期间，2个供试大豆品种可溶性总糖含量均呈波动升高然后降低的变化趋势。花后14至42天，晋大滞绿1号可溶性总糖含量高于晋大74号；2)花后29至42天，晋大滞绿1号蔗糖磷酸合成酶基因SPS4，转化酶基因CInv、CWInv2以及蔗糖合酶基因SS1、SS2-2表达水平显著高于非滞绿品种晋大74号；己糖激酶和果糖激酶基因Hxk和Frk表达量也高于非滞绿品种晋大74号；3)除 SUT4-1外，其余6个蔗糖转运体基因SUTs的表达模式具有明显的品种特异性。花后29至42天，晋大滞绿1号叶片SUTs表达水平较高。综上，滞绿突变对于大豆蔗糖代谢相关基因的表达产生了明显的影响，特别是在鼓粒初期和中期等大豆籽粒形成的关键时期，滞绿品种晋大滞绿1号蔗糖代谢相关基因的表达更加活跃。     

废纸回收材料化利用研究进展

简述了国内外废纸回收利用现状,重点阐述了废纸在建筑填料、制备高附加值纤维衍生物以及复合材料等方面的利用研究现状,并针对废纸材料利用过程中存在的高吸水率和弱结合界面等问题提出了相应的解决方法和研究方向。     

外源褪黑素对干旱胁迫下大豆鼓粒期生理和产量的影响

干旱胁迫降低大豆产量,探究提高大豆耐旱能力和降低产量损失的机制对大豆生产具有重要意义。施褪黑素能缓解干旱胁迫对植株生长的抑制和氧化损伤。本试验于2017—2018年研究叶面喷施褪黑素对干旱胁迫下大豆鼓粒期叶片光合、抗逆、碳氮代谢和产量的影响表明,外源褪黑素提高干旱胁迫下大豆叶片抗氧化酶活性,抑制活性氧的产生和细胞膜损伤,缓解干旱胁迫对光合能力的抑制,提高碳氮同化能力,最终缓解干旱胁迫造成的产量损失。与干旱胁迫相比,褪黑素处理下单株荚数、单株粒数和百粒重两年平均提高了2.9%、0.8%和17.2%,产量(单株粒重)平均提高了14.7%。     

Effects of different active constituents of Gynostemma pentaphyllum on mitochondrial energy metabolism-related proteins in endothelial cells induced by ox-LDL

AIM To investigate the effects of different components of Gynostemma pentaphyllum ［gypenosides (Gps), gypenoside XLIX (GpXLIX) and ginsenoside Rb3 (GRb3)］ on mitochondrial energy metabolism-related proteins in endothelial cells induced by oxidized low-density lipoprotein (ox-LDL). METHODS EA.hy926 cells were divided into control group, model group, Gps group, GpXLIX group and GRb3 group. The cells in control group were cultured only in DMEM complete medium. The cells in model group were treated with 100 mg/L ox-LDL for 48 h. The cells in Gps group, GpXLIX group and GRb3 group were treated with 100 mg/L ox-LDL for 24 h, and then treated with Gps, GpXLIX and GRb3 at 100 mg/L for another 24 h, respectively. The ATP content in each group was detected by ELISA. The expression levels of mitochondrial energy metabolism-related proteins, cytochrome C oxidase subunit 5a （Cox5a）, NADH:ubiquinone oxidoreductase core subunit S1 （Ndufs1）, ATP synthase F1 subunit alpha (ATP5a) and cytochrome C (Cyt C）, were determined by Wes automatic Western blot quantitative analysis system and Western blot. RESULTS Compared with control group, the ATP content in model group was decreased (P<0.01). After drug intervention, the ATP content increased to different degrees in Gps group, GpXLIX group and GRb3 group (P<0.01). The results of Wes automatic Western blot quantitative analysis system were consistent with those of Western blot. These results showed that compared with control group, the protein expression of Cox5a, Ndufs1 and ATP5a in model group was decreased, and the protein expression of Cyt C was increased (P<0.01). After intervention, the protein expression of Cox5a, Ndufs1 and ATP5a was increased and the protein expression of Cyt C was decreased in Gps group, GpXLIX group and GRb3 group (P<0.05 or P<0.01). Among them, the effect of Gps on the protein expression of Cox5a, Ndufs1 and Cyt C was significantly stronger than those of the 2 monomer components, and the effect of GRb3 was found to be superior in the 2 monomer components. The effect of GpXLIX on ATP5a protein was superior to the other 2 components. CONCLUSION Gynostemma total saponins and related active ingredients protect ox-LDL-induced endothelial cells by affecting mitochondrial energy metabolism-related proteins, thereby preventing and treating atherosclerosis.     

H2S的信号分子作用及其对果蔬采后生理代谢的调控研究进展

硫化氢（H2S）作为气体信号分子，参与调控植物体的一系列生命活动，并在果蔬采后生理代谢过程中发挥着重要作用。本文综述了H2S的理化性质、发展应用历史及其在果蔬采后生理调控机制中的信号分子作用，讨论了H2S对果蔬生理代谢的调控作用，包括对果蔬采后抗逆性和品质的影响，以期为采后果蔬的贮藏保鲜提供理论参考。     

天然富含可可碱茶树的研究进展

天然富含可可碱茶树是一类以可可碱为代表性生物碱的稀有茶树种质资源,具有独特的保健功效与挖掘利用价值。从生化成分组成特征、生物代谢途径和可可碱在茶树体内富含的分子机理,对可可茶、红芽茶、秃房茶和厚轴茶4份新近发现的天然富含可可碱茶树进行比较研究与综述。结果发现,可可碱占茶叶干重的质量分数高达2%～6%,咖啡碱则低于0.5%;优势儿茶素单体为没食子酸儿茶素没食子酸酯,而表没食子酸儿茶素没食子酸酯含量较低;咖啡碱合成酶活性位点精氨酸突变为组氨酸使N-甲基转移酶的底物特异性发生变化,从而导致咖啡碱合成酶终止合成咖啡碱并使得可可碱在茶树体内富集。天然富含可可碱茶树资源丰富了茶种的多样性,但开发利用度尚有限,结合当前茶树育种技术的发展状态,对天然富含可可碱茶树种质的繁育与资源挖掘利用进行了展望。     

Regulatory role of l-proline in fetal pig growth and intestinal epithelial cell proliferation

l-proline (Pro) is a precursor of ornithine, which is converted into polyamines via ornithine decarboxylase (ODC). Polyamines plays a key role in the proliferation of intestinal epithelial cells. The study investigated the effect of Pro on polyamine metabolism and cell proliferation on porcine enterocytes in vivo and in vitro. Twenty-four Huanjiang mini-pigs were randomly assigned into 1 of 3 groups and fed a basal diet that contained 0.77% alanine (Ala, iso-nitrogenous control), 1% Pro or 1% Pro + 0.0167% α-difluoromethylornithine (DFMO) from d 15 to 70 of gestation. The fetal body weight and number of fetuses per litter were determined, and the small and large intestines were obtained on d 70 ± 1.78 of gestation. The in vitro study was performed in intestinal porcine epithelial (IPEC-J2) cells cultured in Dulbecco''s modified Eagle medium-high glucose (DMEM-H) containing 0 μmol/L Pro, 400 μmol/L Pro, or 400 μmol/L Pro + 10 mmol/L DFMO for 4 d. The results showed that maternal dietary supplementation with 1% Pro increased fetal weight; the protein and DNA concentrations of the fetal small intestine; and mRNA levels for potassium voltage-gated channel, shaker-related subfamily, member 1 (Kv1.1) in the fetal small and large intestines (P < 0.05). Supplementing Pro to either gilts or IPEC-J2 cells increased ODC protein abundances and polyamine concentrations in the fetal intestines and IPEC-J2 cells (P < 0.05). In comparison with the Pro group, the combined administration of Pro and DFMO reduced the expression of ODC protein and spermine concentration in the fetal intestine, as well as the concentrations of putrescine, spermidine and spermine in IPEC-J2 cells (P < 0.05). Meanwhile, the percentage of cells in the S-phase and the mRNA levels of proto-oncogenes c-fos and c-myc were increased in response to Pro supplementation, whereas depletion of cellular polyamines with DFMO increased tumor protein p53 (p53) mRNA levels (P < 0.05). Taken together, dietary supplementation with Pro improved fetal pig growth and intestinal epithelial cell proliferation via enhancing polyamine synthesis.     

Responses of carbon metabolism and antioxidant system of summer maize to waterlogging at different stages

A field experiment was performed to explore responses of carbon metabolism, antioxidant system and endogenous hormone content of summer maize hybrids DengHai605 (DH605) and ZhengDan958 (ZD958) to waterlogging at the third leaf stage (V3), the sixth leaf stage (V6) and the 10th day after the tasselling stage (10VT). Results showed that waterlogging significantly decreased the contents of zeatin riboside (ZR), indole‐3‐acetic acid (IAA) and gibberellic acid (GA), compared to those of CK. However, leaf abscisic acid (ABA) content was significantly increased by waterlogging at different stages, with the most significant increase was found in the treatment of waterlogging at V3 (V3‐W), with an increase of 30% and 29% for DH605 and ZD958, respectively. Waterlogging significantly decreased antioxidative enzyme activities, accelerating leaf senescence, resulted in the disorder of leaf gas exchange parameters and chlorophyll fluorescence parameters. In addition, waterlogging decreased key enzyme activities of carbon metabolism (ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase), with the most significant reduction in V3‐W, with a decrease of 46% and 49% for DH605, and 53% and 55% for ZD958, respectively. Visibly, waterlogging disturbed carbon metabolism, affected plant endogenous hormone content, accelerated leaf senescence and eventually resulted in a significant reduction in photosynthetic characteristic and grain yield. V3 was most susceptible to waterlogging, followed by V6 and 10VT.     

花前氮亏缺对水稻叶片氮代谢酶活性的影响

以籼型杂交稻中浙优1号和籼粳型杂交稻甬优12为材料,试验分析了花前不同时期氮亏缺处理对水稻叶片氮代谢酶活性的影响。结果表明,花前氮亏缺导致植株上3叶氮浓度、NR、GS、GOGAT、GOT和GPT酶活性大幅下降,GDH活性显著增长,且各叶位对花前氮亏缺敏感度总体上表现为剑叶倒2叶倒3叶;破口期亏氮对籼型杂交稻中浙优1号上3叶氮同化酶活性的影响远小于减数分裂期处理,与之相比,籼粳杂交稻甬优12对破口期亏氮胁迫仍较敏感,表明中浙优1号植株氮代谢酶的亏氮敏感性由减数分裂期至破口期逐步下降,对土壤速效氮的需求同步降低,甬优12则对土壤供氮存在更高需求。