谷氨酰胺对斜带石斑鱼GF-1细胞中C-Myc蛋白的表达与神经坏死病毒复制的影响

为探讨C-Myc表达、谷氨酰胺代谢和神经坏死病毒复制三者之间的关系,本研究首先克隆了斜带石斑鱼鳍条细胞(GF-1)中的C-Myc基因(GF-1-C-Myc),结果显示GF-1-CMyc基因cDNA全长814 bp,开放阅读框(ORF)为285 bp,编码95个氨基酸(aa),有亮氨酸拉链结构域与螺旋-环-螺旋(HLH)结构域。实验表达和纯化了GF-1-C-Myc蛋白,并制备其多克隆抗体。采用实时定量PCR技术(qRT-PCR)与免疫印迹法(WB)检测了GF-1-C-Myc基因的表达和神经坏死病毒的复制。结果显示,缺乏谷氨酰胺会同时抑制GF-1-C-Myc基因的表达和神经坏死病毒(NNV)的复制,添加谷氨酰胺可同时促进GF-1-C-Myc的表达和NNV的复制;此外,NNV感染可上调GF-1-C-Myc基因的表达,并显著消耗GF-1细胞培养液中的谷氨酰胺。研究表明,GF-1-C-Myc基因可调控宿主谷氨酰胺代谢,从而有利于神经坏死病毒的复制。本结果为防控NNV的感染提供了参考。     

Expression and functional characterization of glutamine synthetase from giant freshwater prawn (Macrobrachium rosenbergii) under osmotic stress

The freshwater prawn, Macrobrachium rosenbergii naturally lives in the freshwater, though it migrates to the brackish water environment during spawning that claimed to be resistant on a broad range of saline fluxes. However, little is known about the osmoregulatory patterns and the effect of an enzyme glutamine synthetase (GS) in M. rosenbergii under stress. Here, we described the identification and functional characterization of GS from M. rosenbergii (Mr‐GS) at molecular and protein levels. The identified Mr‐GS was comprised of 361 amino acids that phylogenetically shared the highest identity with other crustaceans and predicted to contain Gln‐synt_C and Gln‐synt_N domains at the respective terminal regions. Tissue distribution analysis in M. rosenbergii revealed that the Mr‐GS was highly expressed in muscle, and commonly existed in other examined tissues in the following order gills > heart > stomach > brain > haemolymph. Whereas, the mRNA of Mr‐GS was significantly up‐regulated in the muscle and gill tissues following challenges with either hyper (0 → 13‰), or hypo (13 → 0‰) osmotic stress at 3, 6 and 12 hr. Furthermore, the level of Glutamine concentration was positively correlated with the GS mRNA and protein expression patterns in hyper‐osmotic stress, whereas in hypo‐osmotic stress a slight decrease in the gills and maintained a level in the muscle tissues at 3, 6 and 12 hr post‐treatments. Our findings suggest that Mr‐GS potentially exhibited the osmoregulation responses in the gill and muscle tissues of M. rosenbergii throughout the time of osmotic stress, which will benefit for future study on osmoregulation.     

Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content

Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg⁻¹ soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.     

饲料中添加谷氨酰胺前体物对镜鲤肠道消化酶及Na~+/K~+-ATPase活性的影响

为了研究谷氨酰胺前体物对镜鲤(Cyprinus carpio specularis)肠道消化酶及Na~+/K~+-ATPase活性的影响,分别用谷氨酰胺(Gln)、谷氨酸(Glu)、α-酮戊二酸(AKG)、L-鸟氨酸-α-酮戊二酸(OKG)、L-精氨酸-α-酮戊二酸(AAKG)、α-酮戊二酸钠(2Na-AKG)替代基础饲料中的葡萄糖(添加量为1.5%),配制成6种等氮等能试验饲料,以基础饲料为对照,分别投喂松浦镜鲤(平均体重(40.27±3.96)g),饲养8周后测定镜鲤肠道消化酶及Na~+/K~+-ATPase活性。结果显示:Glu组前肠蛋白酶活性显著高于对照组;Gln组、Glu组、OKG组和AAKG组中肠蛋白酶活性均显著高于对照组。2Na-AKG组前肠脂肪酶活性显著高于对照组和OKG组;2Na-AKG组中肠脂肪酶活性显著高于对照组和Gln组。2Na-AKG组前肠淀粉酶活性均显著高于对照组和Gln组。Gln组和Glu组前肠Na~+/K~+-ATPase活性均显著高于对照组;不同处理组中肠Na~+/K~+-ATPase活性均显著低于对照组;Glu组、AKG组和OKG组后肠Na~+/K~+-ATPase活性均显著高于对照组,Gln组、AAKG组和2NaAKG组后肠Na~+/K~+-ATPase活性则均显著低于对照组。研究表明,饲料中添加Gln、Glu、OKG和AAKG可显著提高鱼体肠道的蛋白酶活性,添加2Na-AKG可显著提高鱼体肠道的淀粉酶和脂肪酶活性。     

耕作与秸秆还田方式对稻田N_2O排放、水稻氮吸收及产量的影响

保护性耕作是改善农田土壤肥力的重要举措,然而其对作物氮吸收与产量的作用尚不明确。为此,本试验于2016—2017年稻季在湖北省武穴市花桥镇,设置常规翻耕与免耕两种耕作方式以及前茬作物秸秆全量还田与不还田两种秸秆还田方法,研究耕作与秸秆还田方式对稻田土壤N_2O排放、根系酶活性、水稻氮吸收与产量的影响。结果表明,耕作方式显著影响土壤N_2O排放,但不影响根系硝酸还原酶与谷氨酰胺合成酶活性、水稻氮吸收与产量。与翻耕处理相比,免耕处理2016年和2017年土壤N_2O排放量分别显著提高了12.5%～18.2%和21.1%～38.6%。秸秆还田显著影响土壤N_2O排放量、根系酶活性、水稻氮吸收与产量。相对于秸秆不还田处理,秸秆还田处理2016年和2017年土壤N_2O排放量分别显著提高了38.5%～45.5%和13.1%～29.5%。秸秆还田处理相对于不还田处理根系硝酸还原酶与谷氨酰胺合成酶活性分别显著增加了6.7%～45.9%和9.0%～46.7%,水稻氮吸收量提高了12.5%～26.0%,产量增加了9.4%～12.6%。本文认为,虽然秸秆还田提高了水稻氮吸收与产量,但也促进了土壤N_2O的排放,因此在评估保护性耕作稻田温室效应时应加强对温室气体(CH4和N_2O)排放和土壤碳固定影响的长期监测,以期为发展低碳稻作提供理论依据和技术支撑。     

谷氨酰胺对湖羊精液4℃保存效果的影响

为研究湖羊稀释液中添加谷氨酰胺(Gln)对湖羊精液4℃保存效果的影响,在前期筛选的基础稀释液中添加0、0.5、1.0、2.0、4.0、8.0 mg/L的Gln, 4℃条件下保存96 h,每隔24 h检测精子活力、顶体完整率、总抗氧化能力(T-AOC)和丙二醛(MDA)含量指标。结果显示:添加0.5、1.0、2.0、4.0 mg/L的Gln可以有效提高4℃保存条件下的精子活力、顶体完整率和T-AOC水平,并有效抑制MDA的生成(P<0.01),且4.0 mg/L添加浓度保存效果最好,而8.0 mg/L的添加浓度则不利于精液保存。提示:在湖羊精液稀释液中添加4.0 mg/L Gln可有效提高湖羊精液4℃保存的效果。     

谷氨酰胺对水生动物的抗氧化作用及其机理

文章主要综述了谷氨酰胺(glutamine, Gln)对水生动物的抗氧化作用及其机理,旨在深入理解、研究、利用和调控Gln在水生动物上的抗氧化作用,提高水生动物的健康水平,促进生长和发育,发展可持续的渔业.     

牛磺酸、谷酰胺、改良CR1和改良CR2培养液对牛受精卵体外发育的影响

本研究探讨了牛磺酸、谷酰胺、改良CR1 (CR1 无机盐成分 10% 胎牛血清) 和改良CR2 培养液(改良CR1 液 1 m m ol/L谷酰胺和绵羊输卵管分泌液浓度的多种氨基酸)对牛卵子体外受精后的分裂率、囊胚率和囊胚细胞数的影响。结果表明: 牛磺酸和谷酰胺对牛卵子受精后体外发育的影响依赖于胚胎培养液种类; 利用改良CR1 和改良CR2 培养液可成功生产可移植胚胎, 但它们所生产的可移植胚胎的效率无显著差异, 利用改良CR1 培养液生产可移植胚胎的成本更低一些。     

Influence of in ovo inoculation with various nutrients and egg size on broiler performance

This study evaluated the influence of inoculation of different nutrients into eggs of 18-d-old broiler embryos. On d 18 of incubation, before transferring, eggs were injected with a solution containing either maltose, a multivitamin supplement, zinc-glycine, glutamine, a mixture containing all these elements, or sodium chloride (control). After hatching, 2,400 male broiler chicks were placed in an experimental broiler house and distributed into 60 floor pens in a completely randomized design comprising a 2 × 6 factorial arrangement of treatments (2 egg weights × 6 solutions), for a total of 12 treatments. Birds and feed consumption were measured weekly. At 42 d of age, 3 birds per replicate pen were randomly selected for processing. Birds derived from heavier eggs had greater hatchability and hatching weight. At 42 d of age, birds from heavier eggs had higher BW, carcass weight, and breast meat weight. The livability of birds derived from heavy eggs was higher at 7 and 14 d of age. The in ovo inoculation of the nutrients to 18-d-old embryos did not influence live performance or carcass traits. The technique of in ovo inoculation of certain nutrients may be used in industrial poultry production, but further studies are required to define the best solutions or mixture of nutrients to be used.