Ca2+、PEG预处理对干旱胁迫下小麦幼苗某些酶活性的影响

本文结果表明，Ｃａ＾２＋、ＰＥＧ预处理小麦种子具有提高其幼苗ＲＷＣ及ＳＯＤ、ＣＡＴ、ＰＯＤ的活性和降低膜透性的效应，在干旱胁迫下植株生长抑制减轻。随着干旱胁迫的加强、ＳＯＤ、ＣＡＴ、ＰＯＤ活性迅速上升并始终维持较高水平，具体表现为浸种处理ＰＥＧ〉Ｃａ＾２＋〈Ｈ２Ｏ；ＲＷＣ表现为ＰＥＧ〉Ｃａ＾２＋〉Ｈ２Ｏ，植株生长抑制程度表现为ＰＥＧ〈Ｃａ＾２＋〈Ｈ２Ｏ。解除干旱胁迫后，Ｃａ＾２＋，ＰＥＧ浸种处理的     

粉末等离子弧堆焊工艺在修复农机零件中的应用

对粉末等离子弧堆焊工艺用于修复磨损的锤片、犁铧、钉齿和螺旋挖沟机叶片等四种零件进行了试验研究。优选出两种合金粉末并选配一种合金粉末,确定了堆焊部位、焊层厚度和堆焊各零件的工艺规范参数。室内磨损试验及生产试验均证明了修复零件的使用寿命比新品提高一倍以上,作业成本降低49％-77％。     

Histological and immunohistochemical evaluation of duodenal and colonic biopsies after oral bovine lactoferrin supplementation in beagle puppies

Lactoferrin is a natural compound in the milk of mammals and was shown to influence the intestinal micro‐flora and the immune system in mice, calves, dogs and man. The present study was carried out to investigate the effect of orally administered bovine lactoferrin (0, 30, 60 and 120 mg/kg DM feed) on the intestinal morphology and lymphocyte colonization in 36 motherless raised puppies. Endoscopic biopsies from duodenum and colon, taken in week 14, were scored histologically after staining with haematoxylin and eosin (H&E) and lymphocytes (CD3⁺, CD4⁺, CD8⁺) and plasma cells (IgA⁺, IgG⁺, IgM⁺) were enumerated after immunohistochemical staining by computer‐aided quantification. Histological scoring revealed no significant differences amongst the groups. IgG⁺ plasma cells were reduced (p < 0.05) in the lamina propria of the colon of the 30 and the 60 mg group. The number of CD8⁺ lymphocytes was higher (p < 0.05) in the epithelium of the colon of the lactoferrin groups. In conclusion, this study indicated only minimal effects of bovine lactoferrin on the population of selected immune cells in the gut mucosa of puppies. More investigations are needed to describe the impact of lactoferrin on the digestive physiology of puppies.     

血浆蛋白粉不同时间饲喂对肉鸡免疫功能的影响

选用1日龄AA肉鸡240只,随机分为4个处理,每个处理6个重复,每个重复10只鸡.处理一为基础日粮组,处理二、三、四分别添加2.5%血浆蛋白粉(SDPP)替代基础日粮中部分蛋白饲喂7、14、21 d后,换喂相同日粮直到49 d试验结束.前期饲喂21 d后,从每个处理中选择接近平均体质量健康鸡8只腹腔注射大肠杆菌O_2攻毒.结果表明:(1)前期1～14 d连续添加SDPP生产成绩最好,显著高于处理一(P<0.05).后期和全期以1～21 d添加的生产性能略好,与1～14 d差异不显著.(2)添加SDPP提高了肉鸡Ea、Et、脾脏指数、胸腺指数和法氏囊指数,极显著(P<0.01)提高淋巴细胞转化率.(3)SDPP明显降低内鸡死亡率.结果表明,在1～14 d添加SDPP,可促进内鸡生长,增强免疫功能,前期获得最佳ADG的时间是饲喂1～14 d.该饲喂时间肉鸡抗菌能力最强.     

水稻幼苗根系吸收NO3-对细胞膜电位的影响

利用玻璃微电极技术测定了扬稻6号(籼稻)幼苗根尖细胞在吸收不同NO3-浓度(0.01、0.02、0.1、0.2、0.5、1.0和2.0.mmol/L)过程中膜电位的变化。结果表明,1)水稻根系吸收NO3-引起膜的去极化,去极化到一定程度后出现复极化;有小部分水稻根表现为超极化。在0.01～1.0.mmol/L范围内,去极化大小随外界NO3-浓度的增加而增加,且差异显著(P0.05)。0.01.mmol/L.NO3-产生较小的去极化,平均为3.8.mV;0.5.mmol/L.NO3-产生了最大去极化,平均为40.2.mV;当外界NO3-浓度大于1.0.mmol/L时膜电位去极化大小呈下降趋势。根系吸收不同浓度的NO3-而使膜电位去极化的进程符合Michaelis-Menten动力学。2)复极化有部分复极化和完全复极化两种。超极化也有两种:一种是膜电位先超极化,后缓慢复极化;另一种是先出现一个小的去极化,然后是较大幅度的超极化。3)运输蛋白抑制剂PGO抑制了根系吸收NO3-而产生的膜电位的响应。4)对于经CaSO4溶液预培养的水稻来说,C2+主要引起膜电位超极化。     

Assessment of sugar maple tree growth in relation to the partitioning of elements in xylem along a soil acidity gradient

Partitioning of elements in tree xylem is being increasingly studied, as it suggests that elements are potentially mobile within the xylem long after their uptake. A recent study revealed that only the most mobile xylem fraction (water-soluble) of base cations (calcium [Ca], magnesium [Mg], and potassium [K]) increased at higher soil acidity, while the two mobile fractions (water- and acid-soluble) of acidic metals—potentially phytotoxic aluminium (Al), cadmium (Cd) and manganese (Mn)—were significantly enhanced on very acid soils. The current paper presents an investigation of soil-wood chemistry relationships with basal area tree growth. It was hypothesized that the growth of sugar maple would be reduced by low base cation and high acidic metal concentrations in the xylem mobile fractions. Sugar maple trees (n = 55) from six watersheds in southern Quebec, Canada were analysed by sequential chemical extractions for the water-soluble, acid-soluble and residual fractions of base cations (Ca, K, Mg) and acidic metals (Al, Cd, Mn) in xylem. Generally, tree growth was positively correlated to concentrations of base cations in wood (ρ = 0.27-0.50) and soil (ρ = 0.41-0.67), and negatively correlated to concentrations of acidic metals in wood (ρ = −0.33 to −0.52) and soil (ρ = −0.67). However, these relations differed depending on the element fraction considered. Water- and acid-soluble xylem concentrations of base cations and Al were among the best predictors of growth trends (R² = 0.46-0.51). The relationship between acidic metals and tree growth is further discussed.     

Oral administration of L-citrulline changes the concentrations of plasma hormones and biochemical profile in heat-exposed broilers

We examined the effects of oral administration of L-citrulline (L-Cit) on plasma metabolic hormones and biochemical profile in broilers. Food intake, water intake, and body temperature were also analyzed. After dual oral administration (20 mmol/head/administration) of L-Cit, broilers were exposed to a high ambient temperature (HT; 30 ± 1°C) chamber for 120 min. Oral administration of L-Cit reduced (p < .001) rectal temperature in broilers. Food intake was increased (p < .05) by heat stress, but it was reduced (p < .05) by L-Cit. Plasma levels of 3,5,3′-triiodothyronine, which initially increased (p < .0001) due to heat stress, were reduced (p < .01) by oral administration of L-Cit. Plasma insulin levels were increased by heat exposure (p < .01) and oral L-Cit (p < .05). Heat stress caused a decline (p < .05) in plasma thyroxine. Plasma lactic acid (p < .05) and non-esterified fatty acids (p < .01) were increased in L-Cit-treated heat-exposed broilers. In conclusion, our results suggest that oral L-Cit can modulate plasma concentrations of major metabolic hormones and reduces food intake in broilers.     

水牛犊牛血浆外泌体的分离与鉴定

研究旨在从水牛犊牛血浆中分离外泌体,并对分离的外泌体进行分子生物学特征分析和鉴定。采用差速离心法分离3头水牛犊牛的血浆外泌体,并在透射电子显微镜下观察其形态,使用纳米粒度及Zeta电位仪对提取的外泌体进行粒径大小分析,应用Western blotting方法检测外泌体标记蛋白钙联蛋白（Calnexin）、肿瘤易感基因101（TSG101）、CD9、CD81在3头水牛犊牛血浆外泌体中的表达情况。结果显示,从水牛犊牛血浆中分离的外泌体形态多为圆形和椭圆形,直径在30~150 nm;Western blotting检测结果表明,在水牛血浆外泌体表面,特异性蛋白Calnexin、TSG101和CD81阳性表达,CD9不表达。本研究从形态学和分子生物学特征等方面证实研究获得的提取物为外泌体,由此说明,差速离心法可以成功分离提取水牛犊牛血浆中的外泌体,为水牛外泌体的后续研究提供了重要技术基础和参考。     

代乳料原料组成对早期断奶羔羊生长及脏器发育的影响

为了探讨代乳料原料的不同组合效应对早期断奶羔羊的饲喂效果,选取25只甘肃高山细毛羔羊,分为5组,每组5只,对照组羔羊由母羊自由哺乳和放牧;试验组羔羊30日龄断奶,饲喂4种代乳料:A组主原料未膨化,B组主原料膨化,C组主原料膨化+血浆蛋白粉,D组在C组基础上增加乳清粉。试验期为30~90日龄。结果表明:50、70日龄时,对照组羔羊体质量最大,试验组羔羊受断奶应激的影响,相应指标较小。90日龄时,D组体质量显著高于B、C组(P0.05),超过了对照组。30~90日龄阶段,D组日增体质量最大,且显著高于B、C组(P0.05)。对照组脾脏质量显著高于4个试验组(P0.05),且脾脏指数最高。说明在代乳料中添加血浆蛋白粉及增加乳清粉,有利于羔羊健康发育,使代乳料的饲喂效果最佳。     

氧气低温等离子体不同处理功率脱除MDF板中游离甲醛研究

应用低温等离子体技术，研究中密度纤维板中游离甲醛的脱除机理和效率。结果表明，处理时间10min，随着放电功率的增加，甲醛的脱除效率也逐渐增大；处理后板材的静曲强度、弹性模量和肉结奢强度也均有不同程度的提高。