不同精油-羧甲基纤维素钠复合涂膜对草莓贮藏品质的影响

以新鲜草莓为试材,分别采用大蒜精油、山苍子精油、丁香花蕾精油、生姜精油复合羧甲基纤维素钠为涂膜保鲜原料,研究(15±2)℃条件下不同精油涂膜液处理对草莓贮藏品质的影响。结果表明,与对照组相比,山苍子精油、大蒜精油、生姜精油-羧甲基纤维素钠复合涂膜液均能显著降低草莓果实在贮藏过程中的腐烂指数及重量损失,显著抑制贮藏前期草莓果实的呼吸强度,进而抑制草莓果实在贮藏过程中可溶性固形物含量和花色苷含量的下降及丙二醛含量的上升,提高草莓的贮藏品质。其中,山苍子精油-羧甲基纤维素钠复合涂膜液对草莓的保鲜效果最佳,为草莓的贮藏保鲜提供了一种新的方法。     

Extractability and chromatographic separation of rye (Secale cereale L.) flour proteins

A size exclusion – high performance liquid chromatography (SE-HPLC) method originally developed for separating wheat, barley or rice proteins was applied to study the extractability and molecular weight (MW) distribution of rye flour proteins. These were extracted with 50 mmol/l sodium phosphate buffer (pH 6.8) containing 2.0% (w/v) sodium dodecyl sulfate (SDS) and, optionally, 1.0% (w/v) dithiothreitol (DTT). About 95% of the proteins were extracted in buffer containing 2.0% SDS. Addition of 1.0% DTT to such buffer increased the protein extractability to 100%, indicating that rye flour contains some proteins cross-linked by disulfide (SS) bonds. The SE-HPLC profiles revealed that rye flour contains SS-linked HMW-secalins and 75 k γ-secalins which elute in specific peaks. Upon reduction, these SS-linked protein aggregates dissociate and some entrapped albumins, globulins and/or ω-secalins are released. Rye flour albumins and globulins elute over the entire SE-HPLC profile. In contrast, the monomeric ω-secalins and 40 k γ-secalins are detected in specific well resolved SE-HPLC peaks. The applied fast and reproducible method can be used to characterise and quantify rye flour proteins and to determine changes as a result of processing.     

紫外分光光度法测定复方甲磺酸培氟沙星注射液含量

建立了复方甲磺酸培氟沙星注射液中甲磺酸培氟沙星与安乃近的含量测定方法.用紫外分光光度法中倍率减差法消除安乃近干扰,测定甲磺酸培氟沙星含量,检测波长为287、299 nm,溶剂为0.1 mol/L盐酸溶液;用紫外分光光度法中等波长消去法消除甲磺酸培氟沙星干扰,测定安乃近含量,检测波长为261、291 nm,溶剂仍为0.1 mol/L盐酸溶液;整个过程采用棕色容量瓶避光操作.测定甲磺酸培氟沙星含量的回归方程为:ΔA1＝0.089 936 C1,r1＝0.999 6,平均回收率99.66%,RSD=0.61%;测定安用近含量的回归方程为:ΔA2＝0.024 888 C2,r2＝0.999 6,平均回收率99.81%,RSD=0.41%.本方法简单、快速、易于操作.     

免疫增强剂硒对雏鸡免疫功能的影响

300只1日龄南海黄雏鸡随机分为5组，Ⅰ－Ⅳ组为加硒试验组，Ⅴ组为不加硒对照组。全部试验鸡均饲喂不缺硒饲料（含硒0．18mg/kg)，并以饮水方式进行新城疫首免和2免。Ⅰ、Ⅱ、Ⅲ、Ⅳ组分别于2次免疫前2d起连续3d以亚硒酸钠饮水给硒0．25、0．5、0．75、1．0mg/kg。结果表明，各组平均血清硒含量变化与饮水给硒剂量一致；Ⅰ－Ⅳ组的新城疫HI抗体滴度显著或极显著地高于Ⅴ组（P＜0．05或P＜0．01）；Ⅲ、Ⅳ组体重显著或极显著地高于Ⅴ组（P＜0．05或P＜0．01）；各加硒试验组特别是Ⅲ组在红细胞Ⅰ型补体受体（CR1）活性较Ⅴ组高；各组免疫器官指数未出现显著性差异。     

硒对黄曲霉毒素B1中毒雏鸭血清抗氧化功能的影响

为观察黄曲霉毒素B1(aflatoxin B1,AFB1)对试验雏鸭血清抗氧化功能的影响及亚硒酸钠对AFB1的颉颃效应,选用7日龄雏鸭90只,随机分为3组,每组30只.Ⅰ组为空白对照组,灌胃同等量二甲基亚砜;Ⅱ、Ⅲ组为试验组.Ⅱ组、Ⅲ组每天按0.1 mg/kg体重剂量灌胃AFB1,同时给Ⅲ组每天按l mg/kg剂量灌胃...     

同色兜兰种子非共生萌发试验

研究了基本培养基、种子成熟度及次氯酸钠溶液处理对同色兜兰种子萌发的影响。结果表明,授粉后150 d的种子在1/4MS基本培养基附加0.5 mg/L NAA、100 mL/L椰子水、1.0 g/L活性炭和20 g/L蔗糖的培养基上萌发率最高,播种后90 d萌发率可达70.3%;授粉后240 d的种子在含有0.5%有效氯的次氯酸溶液中处理40 min能最有效地提高种子的萌发率,成熟种子的萌发率从14.3%提高到69.0%。     

头孢噻呋钠在猪体内的药代动力学和生物利用度研究

用微生物杯蝶法测定血清药物浓度,6头实验猪按5 mg/kg单剂量静注、肌注头孢噻呋钠(Ceftiofur Sodium),对其药代动力学和生物利用度进行了研究.试验菌为蜡样芽孢杆菌1.1687,结果平均回收率为96.52%,血清最低检测浓度为0.15 μg/ml,日内日间变异系数为2.5%～4.9%,血清浓度在0.3～0.8 μg/ml范围内呈良好线性关系(r=0.9884).药时数据经Mcpkp药代动力学计算机程序处理,猪静注、肌注头孢噻呋钠体内药物运转都符合二室开放模型,其中静注的药代动力学参数为T1/2α=2.22 h,T1/2β=14.64 h, K12=0.09/h, K21=0.078/h, Kel=0.20/h, V1=0.34 l/kg, VB =1.38 l/kg, CLB=0.07 l/kg/h,AUC=76.56 mg/l*h; 肌注药代动力学参数为Tmax=0.69 h,Cmax=12.09 μg/ml,T1/2ka=0.19 h,T1/2β=15.18 h,Kel=0.23/h,K12=0.14/h,K21=0.08/h;生物利用度为AUCi.m/AUCi.v=87.97%.     

Effects of temporary cessation of milking following intramammary cefazolin sodium infusion on residual antibiotic in lactating dairy cows

The aims of studies were to estimate the withdrawal period of antibiotic from milk after the intramammary infusion of cefazolin sodium (CEZ) in cows with difficulties in frequent milk discharge due to disease such as teat injury. The period was compared among cows milked twice a day after 150 or 450 mg of CEZ were administered to all quarters (Study 1, 2) and the cows in which milking of front-right quarter was ceased for five days after administration of these infusions to only that quarter (Study 3). In Studies 1 and 2, the median of 17.66 µg/ml and 83.18 µg/ml of CEZ were detected in the samples of first milking after intramammary administration, respectively; however, there was no residual antibiotic by 72 hr in all cows. In Study 3, the median of 1.96 µg/ml of CEZ was detected in the sample after the resumption of milking at 120 hr, and the residual was eliminated by 174 hr. The withdrawal period may be prolonged by the cessation of milking after administration, and the period is the total time from cessation to 72 hr after the resumption of milking.     

Evaluating Predictive Values of Various Physiological Indices for Salinity Stress Tolerance in Wheat

Soil salinity is a worldwide issue that affects agricultural production. The understanding of mechanisms by which plants tolerate salt stress is crucial for breeding varieties for salt tolerance. In this work, a large number of wheat (Triticum aestivum and Triticum turgidum) cultivars were screened using a broad range of physiological indices. A regression analysis was then used to evaluate the relative contribution of each of these traits towards the overall salinity tolerance. In general, most of the bread wheats showed better Na⁺ exclusion that was associated with higher relative yield. Leaf K⁺/Na⁺ ratio and leaf and xylem K⁺ contents were the major factors determining salinity stress tolerance in wheat. Other important traits included high xylem K⁺ content, high stomatal conductance and low osmolality. Bread wheat and durum wheat showed different tolerance mechanisms, with leaf K⁺/Na⁺ content in durum wheat making no significant contributions to salt tolerance, while the important traits were leaf and xylem K⁺ contents. These results indicate that Na⁺ sequestration ability is much stronger in durum compared with bread wheat, most likely as a compensation for its lesser efficiency to exclude Na⁺ from transport to the shoot. We also concluded that plant survival scores under high salt stress can be used in bread wheat as a preliminary selection for Na⁺ exclusion gene(s).     

Role of NF-κB in diabetic neuropathy

AIM:To investigate the role of NF-κB in diabetic neuropathy. METHODS:The diabetic rats were induced by intraperitoneal injection of streptozocin (STZ). The pain behavior test was used to detect the mechanical and thermal withdraw threshold of the rats’ bilateral hind paws. The protein levels of p-NF-κB and t-NF-κB in the rats’ L4 and L5 dorsal root ganglions (DRG) were determined by Western blotting. The expression of Nav1.7 in DRG of diabetic neuropathy rats with or without NF-κB inhibitor PDTC was detected by the method of immunohistochemistry. RESULTS:The mechanical and thermal withdraw threshold of bilateral hind paws in the diabetic rats was decreased from 4 weeks to 12 weeks after injection of STZ. The protein levels of p-NF-κB in L4 and L5 DRG were significantly increased in the rats with diabetic neuropathy. Intrathecal administration of NF-κB inhibitor PDTC attenuated the increase in p-NF-κB and Nav1.7 in L4 and L5 DRG. Pain behaviors were also alleviated by PDTC. CONCLUSION: The increase in p-NF-κB is closely rela-ted to the generation of diabetic neuropathy. Inhibition of NF-κB blocks pain behaviors and the over-expression of Nav1.7 in DRG.