外源脱落酸和冠菌素对小麦籽粒萌芽的影响

[目的]通过研究外源脱落酸(ABA)和冠菌素(COR)对小麦籽粒萌芽的影响,探索COR用于防治小麦收获期穗发芽的可行性。[方法]以易穗发芽的白皮小麦品种济麦22和抗穗发芽的红皮小麦品种扬麦16为材料,以不同浓度ABA和COR处理两品种小麦籽粒后进行萌芽,测定萌芽率、芽长以及萌芽过程中的α-淀粉酶活性。[结果]38μmol/L以上浓度的ABA处理和0.05μmol/L以上浓度的COR处理均对两品种籽粒的萌发及芽的生长表现出显著的抑制作用,且COR抑制小麦种子萌发的生物活性约为ABA的200～1 500倍;浓度高于76μmol/L的ABA和0.05μmol/L的COR对两品种小麦籽粒萌发过程中的α-淀粉酶活性有抑制作用,且浓度越高抑制程度越大。[结论]ABA和COR可能通过抑制α-淀粉酶活性来抑制小麦籽粒的萌发和芽的生长;同浓度同一抑制剂处理下,白皮的济麦22萌芽及α-淀粉酶活性受抑制的程度显著高于扬麦16。该研究为COR用作控制大田小麦收获期穗发芽的可行性提供理论依据。     

多杀菌素的作用机理及其抗药性的研究进展

多杀菌素是一类新的杀虫剂,具有高效、低毒、选择性强、对环境安全的特点。其作用机制是通过激活烟碱型乙酰胆碱受体(nAChR),使正常昆虫神经细胞去极化,也可通过抑制γ-氨基丁酸受体(GABAR)使神经细胞超极化。本文综述了多杀菌素作用机理及其抗药性的研究进展。     

网箱与微流水养殖的齐口裂腹鱼肌肉营养成分的比较与分析

本研究比较和分析网箱与微流水两种养殖模式下体质量(76.5±17.8)g和(67.2±8.1)g的齐口裂腹鱼Schizothorax prenanti肌肉常规营养成分。结果显示:两组齐口裂腹鱼肌肉中一般营养成分含量不存在显著性差异,均含有18种氨基酸;除色氨酸(Trp)和组氨酸(His)外,网箱组齐口裂腹鱼肌肉中其余氨基酸、氨基酸总量、必需氨基酸总量和鲜味氨基酸总量均显著低于微流水组。氨基酸评分(AAS)和化学评分(CS)结果显示:两组齐口裂腹鱼肌肉中必需氨基酸构成合理,色氨酸均为第一限制性氨基酸,赖氨酸在必需氨基酸中评分最高。两组齐口裂腹鱼肌肉中均含有21种脂肪酸,网箱组饱和脂肪酸(SFA)总量和单不饱和脂肪酸(MUFA)含量显著低于微流水组,而多不饱和脂肪酸(PUFA)含量显著高于微流水组,且n-3/n-6比值要高于网箱组。综上所述,微流水养殖的齐口裂腹鱼营养价值更高。     

费氏丙酸杆菌谢氏亚种和植物乳杆菌亚油酸异构酶结构及酶学性质

 【目的】对来源于植物乳杆菌（Lactobacillu plantarum）和费氏丙酸杆菌谢氏亚种（Propionibacteriu freudenreichii ssp. shermanii）亚油酸异构酶酶学特性开展研究,探讨不同来源的亚油酸异构酶酶学性质存在的差异。【方法】通过酶反应动力学方法及电泳技术测定了酶的最适反应条件、米氏常数、酶的分子量,并在此基础上,采用高效液相色谱（HPLC）与电喷雾离子化/质谱（ESI-MS）相结合的方法测定了L. plantarum和P. freudenreichii ssp. shermanii亚油酸异构酶的氨基酸序列。【结果】P. freudenreichii ssp. shermanii亚油酸异构酶的最适pH为8.0,最适反应温度是30℃,Km=20.53 μmol•L-1,Vmax=0.44 μg•ml-1•min-1;L. plantarum亚油酸异构酶的最适pH为7.5,最适反应温度是为50℃,Km=17.85 μmol•L-1,Vmax=0.73 μg. ml-1•min-1。【结论】来源于L. plantarum和P. freudenreichii ssp. shermanii亚油酸异构酶的全氨基酸序列不同,但两者具有一定的同源性,且两者酶学特性也有差异。     

Effects of guanidinoacetic acid on growth performance,creatine metabolism and plasma amino acid profile in broilers

The objective of this study was to assess the effects of guanidinoacetic acid (GAA) on growth performance, creatine deposition and blood amino acid (AA) profile on broiler chickens. In Exp. 1, a total of 540 one‐day‐old Arbor Acres male broilers (average initial body weight, 45.23 ± 0.35 g) were divided randomly into five treatments with six replicates of 18 chicks each. Broilers were fed corn–soybean meal‐basal diets supplemented with 0, 600, 800, 1,000 or 1,200 mg/kg GAA for 42 days respectively. Results showed that dietary GAA inclusion increased average daily gain (ADG) and improved gain‐to‐feed ratio (G:F) from 1 to 42 days (p < 0.01). However, average daily feed intake was unaffected by dietary supplementation of GAA. As GAA inclusion increased, the contents of creatine in plasma and kidney were increased (linear, p < 0.01), while the contents of GAA and creatine in liver were decreased (linear, p < 0.01). Similarly, GAA supplementation was inversely related to concentrations of most essential AA in plasma. In Exp. 2, a total of 432 one‐day‐old Arbor Acres male broilers (average initial body weight, 39.78 ± 0.58 g) were divided randomly into four treatments with six replicates of 18 chicks each. Birds were fed a corn–soybean meal‐basal diet supplemented with 0, 200, 400 or 600 mg/kg GAA for 42 days respectively. Dietary inclusion of 600 mg/kg GAA significantly increased ADG and G:F of broilers (p < 0.05). In conclusion, dietary supplementation of 600–1,200 mg/kg GAA can effectively improve the growth performance in broiler chickens by affecting creatine metabolism and utilization efficiency of essential AA, and 600 mg/kg GAA is the minimum dose for improving performance.     

茉莉酸甲酯对葡萄植株不定根发育的影响

利用不同浓度的茉莉酸甲酯（MeJA）对葡萄组培植株进行处理,进而分析其生理及基因表达变化,结果表明MeJA能抑制植株不定根的分化和伸长,诱导根、茎、叶组织中的脱落酸（ABA）含量升高,但降低赤霉素（GA）、生长素（IAA）和细胞分裂素（ZR）的含量,且影响叶片中叶绿素代谢导致褪绿黄化。MeJA能诱导植物体内茉莉酸合成代谢基因表达进而提高内源茉莉酸的含量,诱导ABA合成代谢和信号路径中的基因表达,但是会抑制生长素、赤霉素、细胞分裂素、油菜素内酯合成代谢基因的表达,抑制了与根发育和延伸相关基因VvXET、VvEXPB2、VvEXPA7和VvWUS的表达,进而抑制不定根的发生,导致植物发育缓慢。因此,MeJA通过影响其他激素的合成代谢来调控它们在植物中的含量,导致内源激素不平衡影响植株发育,并调控植株根的发育状态,在不定根发育方面起负向调控作用。     

Necrotic enteritis challenge regulates peroxisome proliferator-1 activated receptors signaling and β-oxidation pathways in broiler chickens

Necrotic enteritis (NE) is an important enteric disease in poultry and has become a major concern in poultry production in the post-antibiotic era. The infection with NE can damage the intestinal mucosa of the birds leading to impaired health and, thus, productivity. To gain a better understanding of how NE impacts the gut function of infected broilers, global mRNA sequencing (RNA-seq) was performed in the jejunum tissue of NE challenged and non-challenged broilers to identify the pathways and genes affected by this disease. Briefly, to induce NE, birds in the challenge group were inoculated with 1 mL of Eimeria species on day 9 followed by 1 mL of approximately 10⁸ CFU/mL of a NetB producing Clostridium perfringens on days 14 and 15. On day 16, 2 birds in each treatment were randomly selected and euthanized and the whole intestinal tract was evaluated for lesion scores. Duodenum tissue samples from one of the euthanized birds of each replicate (n = 4) was used for histology, and the jejunum tissue for RNA extraction. RNA-seq analysis was performed with an Illumina RNA HiSeq 2000 sequencer. The differentially expressed genes (DEG) were identified and functional analysis was performed in DAVID to find protein–protein interactions (PPI). At a false discovery rate threshold <0.05, a total of 377 DEG (207 upregulated and 170 downregulated) DEG were identified. Pathway enrichment analysis revealed that DEG were considerably enriched in peroxisome proliferator-activated receptors (PPAR) signaling (P < 0.01) and β-oxidation pathways (P < 0.05). The DEG were mostly related to fatty acid metabolism and degradation (cluster of differentiation 36 [CD36], acyl-CoA synthetase bubblegum family member-1 [ACSBG1], fatty acid-binding protein-1 and -2 [FABP1] and [FABP2]; and acyl-coenzyme A synthetase-1 [ACSL1]), bile acid production and transportation (acyl-CoA oxidase-2 [ACOX2], apical sodium–bile acid transporter [ASBT]) and essential genes in the immune system (interferon-, [IFN-γ], LCK proto-oncogene, Src family tyrosine kinase [LCK], zeta chain of T cell receptor associated protein kinase 70 kDa [ZAP70], and aconitate decarboxylase 1 [ACOD1]). Our data revealed that pathways related to fatty acid digestion were significantly compromised which thereby could have affected metabolic and immune responses in NE infected birds.     

Phospholipase A<Subscript>1</Subscript> activity of crude enzyme extracted from the ovaries of skipjack tuna

The phospholipid class composition, fatty acid composition and phospholipase A₁ (PLA₁) activity from the ovaries of skipjack tuna were compared with those of six other species of marine fish. In the skipjack ovaries, the lysophosphatidylcholine (LPC) proportion for the phospholipid, the docosahexaenoic acid (DHA) percentage for the total fatty acids of the phospholipids and the PLA₁ activity of the crude enzyme were the highest among those of the seven species. The optimum pH and temperature for the PLA₁ activity of the crude enzyme from the skipjack ovaries were in the range of pH 6–7 and 20–30°C, respectively, and calcium ions were not required. As a substrate, phosphatidylcholine was more easily hydrolyzed than phosphatidylethanolamine by this enzyme, and the plasmalogen-type phospholipid was much lower than the acyl-type phospholipid. After a 6-h hydrolysis reaction of the purified phospholipid extracted from the mixed ovaries of skipjack and yellowfin tuna by this enzyme, the LPC ratio of the phospholipid increased from 20 to 72.6% and the percentage of DHA for the total fatty acids of the phospholipid also increased. Thus, skipjack ovaries might possibly be used as a source of PLA₁.     

HPLC-PDA法测定恩诺沙星注射液中非法添加乙酰甲喹、水杨酸

建立了高效液相色谱法测定恩诺沙星注射液中非法添加乙酰甲喹、水杨酸含量的方法。试验采用十八烷基硅烷键合硅胶色谱柱,以0.025moL/L磷酸溶液-乙腈(85:15, v/v)为流动相,流速为1.0 mL/min,二极管阵列检测器进行全扫描和232nm波长测定。结果表明乙酰甲喹在0.5～20μg/mL范围内线性良好,R²=1.000,回收率在98.21%～107.94%之间;水杨酸在1.0～50μg/mL范围内线性良好,R²=1.000,回收率在96.33%～100.84%之间;RSD在0.11%～3.44%之间。本方法准确、可靠、重现性好,可用于恩诺沙星注射液中非法添加乙酰甲喹、水杨酸的定性和定量检测。     

‘鸭梨’、‘新高’果实发育过程中果肉及种子有机酸含量的变化

为了研究梨种子对果实生长发育的影响,采用高效液相色谱(HPLC)技术对‘鸭梨’和‘新高’果实发育过程中果肉和种子中的有机酸含量进行了分析。结果表明：两个品种果肉中主要的有机酸组分均为苹果酸和奎尼酸,发育初期‘鸭梨’与‘新高’果肉中各组分的比率相近,但果实成熟时‘新高’果肉中苹果酸的比率59.98%显著高于‘鸭梨’的37.51%;两个品种种子中的有机酸组分比率的动态变化相近,与果肉相反,主要表现在奎尼酸比率的增加和苹果酸比率的减少。两个品种果肉和种子中的总酸、草酸、奎尼酸,苹果酸,莽草酸,柠檬酸含量均随着果实的成熟呈下降趋势,‘鸭梨’果肉中的奎尼酸、莽草酸、柠檬酸含量高于‘新高’;‘新高’在果实成熟时种子中的总酸含量4.59mg/g显著低于‘鸭梨’13.00mg/g,‘鸭梨’成熟果实种子中的草酸、奎尼酸、莽草酸含量显著高于‘新高’;在果实发育初期,种子中的苹果酸含量极显著高于果肉,在果实成熟时则显著低于果肉。