一种高质量天门冬基因组DNA提取方法

针对天门冬[Asparagus cochinchinensis(Lour.)Merr.]成熟叶片富含多糖、多酚、蛋白质及其他次生代谢物质的特点,采用改良CTAB法对其基因组总DNA进行提取,并对DNA进行质量检测。结果表明,改良CTAB法可从天门冬成熟叶片中获得纯度高、完整性好的总DNA,其OD260 nm/OD280 nm为1.86,OD260 nm/OD230 nm为2.36,浓度为390μg/mL,产率达11.7μg/g,多糖、多酚和RNA杂质被去除干净,无降解现象,说明该方法提取的天门冬基因组总DNA质量较高。     

苦参碱对奶牛乳腺上皮细胞增殖、凋亡及抗氧化能力的影响

【目的】探究苦参碱对体外培养的奶牛乳腺上皮细胞(BMECs)增殖、凋亡及抗氧化能力的影响。【方法】利用含0(A组),25(B组),50(C组),75(D组)和100μg/mL(E组)苦参碱的培养基培养奶牛乳腺上皮细胞。通过四甲基偶氮唑盐(MTT)法检测BMECs活性,采用流式细胞仪(AnnexinV/PI双染法)检测苦参碱对BMECs凋亡的影响,并检测苦参碱对BMECs抗氧化酶活性及丙二醛(MDA)含量的影响,采用real-time PCR对BMECs中Caspase-3、p53、STAT1和SOCS3基因的相对表达量进行检测。【结果】用药5d时,低质量浓度(25和50μg/mL)苦参碱对BMECs增殖具有促进作用,高质量浓度(75和100μg/mL)苦参碱对细胞增殖具有抑制作用;B~E组BMECs的凋亡率均极显著高于A组(P0.01);B~E组BMECs培养上清液中NO和乳酸脱氢酶(LDH)水平明显高于A组。B~E组BMECs的过氧化氢酶(CAT)活性均比A组高,其中C组极显著高于A组(P0.01);B~E组的谷胱甘肽过氧化物酶(GSH-Px)活性均极显著高于A组(P0.01),E组的超氧化物歧化酶(SOD)水平极显著高于A组(P0.01),各组MDA含量无显著性差异。与A组相比,苦参碱上调了B~E组BMECs中Caspase-3、p53、STAT1和SOCS3基因的相对表达量。【结论】低质量浓度苦参碱能够促进BMECs增殖,高质量浓度苦参碱则会抑制BMECs增殖;不同质量浓度苦参碱均可提高BMECs的抗氧化能力,其中50μg/mL苦参碱提高BMECs抗氧化能力的效果最明显。     

南方双季稻区小行距插秧机的改进设计与试验

针对300mm行距插秧机在南方双季稻区栽插行距过大、穴数过少及不能充分发挥机插稻的增产潜力问题,在300mm行距插秧机结构的基础上,通过机械优化设计和田间农艺技术相结合的方法,对其插植部箱体、苗箱、支架(包括左右支架和中间支架)和浮板4个关键部位技术参数改进设计,研制出了适合南方双季稻区作业的2ZS-488B型(264mm行距)插秧机,并于2012-2013年在江西省2个试验点进行不同早晚稻品种机插行距的大田对比试验。结果表明:该插秧机作业性能稳定,漂秧率、伤秧率和漏插率分别为1.55%、2.68%和1.93%,相对均匀度合格率为89.54%。与300mm行距插秧机相比,其产量平均增产529.43kg/hm2,平均增产率达8.57%。该研究结果创新了南方双季稻区新的机械化栽插方式,有利于农机农艺的有效融合。     

引自国际马铃薯中心的品种资源在青海对晚疫病的田间抗性鉴定

在青海省海拔2000～2500m和2500～3000m两个不同生态区域设置抗性观测圃,调查评价从国际马铃薯中心(CIP)引进的60份资源田间晚疫病抗性,资源D9在整个生育期表现出免疫症状,15个资源表现为高抗,18个资源表现抗病,同时还对晚疫病菌流行生理小种的毒性基因进行动态监测。     

福建省沿海防护林体系建设国债项目造林质量探讨

本文介绍了福建省沿海防护林体系建设及国债造林现状,分析了国债造林难度和影响造林质量的主要因素,提出提高国债造林质量对策。     

Dietary fiber in a low-protein diet during gestation affects nitrogen excretion in primiparous gilts,with possible influences from the gut microbiota

We investigated the effects of dietary fiber (DF) supplementation in normal or low crude protein (CP) diets on reproductive performance and nitrogen (N) utilization in primiparous gilts. In total, 77 Landrace × Yorkshire pregnant gilts were randomly allocated to four dietary treatments in a 2 × 2 factorial design. The groups comprised 1) equal intake of normal CP (12.82% and 0.61% total lysine), 2) low CP (LP) (10.53% and 0.61% total lysine), and 3) with or 4) without DF supplementation (cellulose, inulin, and pectin in a 34:10:1 ratio). A low-protein diet during gestation significantly reduced daily weight gain from days 91 to 110 of pregnancy (−162.5 g/d, P = 0.004). From N balance trials conducted at days 35 to 38, 65 to 68, and 95 to 98 of pregnancy, DF addition increased fecal N excretion at days 65 to 68 (+24.1%) and 95 to 98 (+13.8%) of pregnancy (P < 0.05) but reduced urinary N excretion (P < 0.05), resulting in greater N retention at each gestational stage. DF increased fecal microbial protein levels and excretion during gestation. An LP diet also reduced urinary N excretion at different gestational stages. An in vitro fermentation trial on culture media with nonprotein N urea and ammonium bicarbonate (NH₄HCO₃) as the only N sources revealed that microbiota derived from feces of gestating gilts fed the high DF diet exhibited a greater capacity to convert nonprotein N to microbial protein. Microbial fecal diversity, as measured by 16S rRNA sequencing, revealed significant changes from DF but not CP diets. Gilts fed an LP diet had a higher number of stillbirths (+0.83 per litter, P = 0.046) and a lower piglet birth weight (1.52 vs. 1.37 kg, P = 0.006), regardless of DF levels. Collectively, DF supplementation to gestation diets shifted N excretion from urine to feces in the form of microbial protein, suggesting that the microbiota had a putative role in controlling N utilization from DF. Additionally, a low-protein diet during gestation negatively affected the litter performance of gilts.     

Sulfadiazine pharmacokinetics in grass carp (Ctenopharyngodon idellus) receiving oral and intravenous administrations

This study aimed to examine the bioavailability (BA) and pharmacokinetic (PK) characteristics of sulfadiazine (SDZ) in grass carp (Ctenopharyngodon idellus) after oral and intravenous administrations. Blood samples were collected at predetermined time points of 0.083, 0.17, 0.5, 1, 2, 4, 8, 16, 24, 48, 72, and 96 hr (n = 6). The samples were extracted and purified by organic reagents and determined by the ultra‐performance liquid chromatography. The software named 3P97 was used to calculate relevant PK parameters. The results demonstrated that the concentration–time profile of SDZ was best described by a one‐compartmental open model with first‐order absorption after a single oral dose. The main PK parameters of the absorption rate constant (K_α), the absorption half‐life (t_{1/2 Kα}), the elimination rate constant (K_e), the elimination half‐life (t_1/2Ke), and the area under concentration–time profile (AUC_0‐∞) were 0.3 1/h, 2.29 hr, 0.039 1/h, 17.64 hr, and 855.78 mg.h/L, respectively. Following intravenous administration, the concentration–time curve fitted to a two‐compartmental open model without absorption. The primary PK parameters of the distribution rate constant (α), the elimination rate constant (β), the distribution half‐life (t_1/2α), the elimination half‐life (t_1/2β), the apparent distribution volume (V_SS), the total clearance (CL), and AUC_0‐∞ were 9.62 1/hr, 0.039 1/hr, 0.072 hr, 17.71 hr, 0.33 L/kg, 0.013 L h^?1 kg^?1, and 386.23 mg.h/L, respectively. Finally, the BA was calculated to be 22.16%. Overall, this study will provide some fundamental information on PK properties in the development of a new formulation SDZ in the future and is partially beneficial for the appropriate usage of SDZ in aquaculture.     

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.     

我国农业机械化与城镇化关系的协整分析

在讨论我国农业机械化发展的内在机制以及与城镇化关系的基础上,运用协整分析方法建立时间序列数据模型,经过格兰杰因果关系检验,验证农业机械化与城镇化之间的长期稳定关系,进一步建立误差修正模型探讨这种稳定关系在长期内与短期内的动态变化特征,并预测我国2020年农业机械化发展水平。结果表明,在长期内,城镇化率增加一个单位农业机械化水平将提高1.09个单位。但是,农业机械化对当期城镇化的推进反应是滞后的,而是反映在长期趋势上。预测显示,2020年我国农业机械化水平将达到67.45%。