Quantitative capillary reversed passive latex agglutination test for C-reactive protein (CRP) in the dog

A capillary reversed passive latex agglutination test (capillary RPLA) was developed which allows quantification of serum C-reactive protein (CRP) within approximately 15 min. The logarithmic regression line (calibration curve) obtained after measuring each CRP concentration three times in twofold dilutions of a standard canine serum containing 222 g/ml of CRP was y=6.394+0.030x (r=0.995). Capillary RPLA permitted quantification of CRP in the range 6.9–222 g/ml. The coefficients of variation ranged from 10.28% to 12.40%. The recovery rates (percentage recovery) of CRP by capillary RPLA were within the range 87% to 106%. On measuring the CRP concentrations in sera from 78 dogs by capillary RPLA, single radial immunodiffusion (SRID) and enzyme-linked immunosorbent assay (ELISA), close correlations were demonstrated between SRID and capillary RPLA (y=7.250+1.109x, r=0.978), between SRID and ELISA (y=3.042+1.059x, r=0.967), and between capillary RPLA and ELISA (y=1.778+0.929x, r=0.962). Capillary RPLA may be considered useful as a routine biochemical technique for measurement of serum CRP concentration in the dog.Abbreviations CRP C-reactive protein - ELISA enzyme-linked immunosorbent assay - RPLA reversed passive latex agglutination test - SRID single radial immunodiffusion     

应用种子蛋白电泳图谱对高羊茅品种进行鉴别与聚类研究

利用种子贮藏蛋白进行二二烷其磺酸钠－聚丙烯酰胺凝脉电泳,对２３个高羊茅品种进行了 分析。表明该方法成本低,效率高,重复性好,能有效地反应高羊茅品种的遗传差异和亲缘关系。电泳谱带聚类分析所得到的类群,能代表生产上,饲用,草坪用类型以及两种用途中的主要生态类型。     

Correlation between hydrolytic enzyme activities measured in bean seedlings afterTrichoderma koningii treatment combined with pregermination and the protective effect againstPythium splendens

An experimental protocol consisting in the colonisation of pregerminated bean seeds dressed withTrichoderma sp. was used in order to study the mechanisms correlated with the protective effect againstPythium splendens. Seed dressed with TH-11 (T. koningii) for 24 h presented a higher protective effect and a higher level of seed colonisation as compared to those dressed with TH-13 (T. longibranchiatum). The levels of seed coat colonisation by TH-11 and TH-13 was shown to be correlated with the carboxymethylcellulase activity, as measured in the seed coats retreived from germinating dressed bean seeds. The seed coat colonisation was also associated with an increased activities of endo-1,3--glucanase and endochitinase measured in seed extracts, and an inhibitory effect of seed extracts onPythium sporangia germination. Pretreatment of TH-13-dressed seeds with a commercial cellulase improved all parameters mentioned above, thus suggesting a role of cellulase activity in the colonisation process and the linked protective effect. The possible role of hydrolytic enzymes in the protective effects is discussed.     

Epidemiology of beet necrotic yellow vein virus in sugar beet at different initial inoculum levels in the presence or absence of irrigation

A field experiment was set up in 1988 to study the development of rhizomania disease of sugar beet at different inoculum levels of beet necrotic yellow vein virus (BNYVV) in soil. Five, tenfold different, inoculum levels were created by addition of the approximate amounts of 0, 0.5, 5, 50 and 500 kg infested soil per ha (the latter corresponding to 0.01% v/v calculated to the tillage layer). A drip irrigation treatment was applied to study the influence of soil moisture on disease. Susceptible sugar beet, cv. Regina, was grown for three consecutive years.In the first year, root symptoms were not observed, but BNYVV-infected plants were detected by ELISA in low numbers at all inoculum levels at harvest. After late drilling in 1989, high numbers of infected plants, up to 90–100% in plots with the highest inoculum level, were detected already in June. Root symptoms were also observed from June onwards. In both these years disease incidence increased in time and was significantly influenced by the initial inoculum level. In the third year, the whole field was heavily diseased, and only for the non-irrigated plots incidence differed for different initial inoculum levels. The expression of symptoms by BNYVV-infected plants was influenced by initial inoculum level, thus by the amount and timing of primary infection.Root weight at harvest was not affected, but sugar content decreased with increasing inoculum level already in 1988, leading to a reduction in sugar yield of 10% at the highest inoculum level. In 1989, both root weight and sugar content decreased progressively with increasing inoculum level, resulting in sugar yield reductions of 11–66% (down to approximately 3000 kg ha^–1) for low to high inoculum levels compared to the control. As the control plots became contaminated, all yields were low in 1990, still showing a decrease with increasing inoculum level in the non-irrigated plots, but an overall mean sugar yield of 3323 kg ha^–1 for the irrigated ones.Sodium and -amino nitrogen content of the root, additional quality parameters determining extractability of sucrose, showed an increase and decrease, respectively, with increasing initial inoculum level already in the first year. The relative differences in contents compared to those from the control were largest for Na content. A significant negative correlation was found between Na (mmol kg^–1 root) and sugar content (% of fresh weight); linear for 1988, exponential for 1989 and 1990.In spring 1989, the infestation of individual plots was assessed using a quantitative bioassay estimating most probable numbers (MPNs) of infective units of BNYVV per 100 g dry soil. The relationship between the MPns determined and root weight, sugar content and sugar yield at harvest could be described by Gompertz curves. The increase in disease incidence with increasing MPN in 1989 was adequately fitted with a logistic equation.     

Reduced protein kinase C activity and endogenous protein phosphorylation in ethionine-induced fatty liver in cows

Protein kinase C (PKC) activity was evaluated and the phosphorylation of its endogenous substrates was explored in fatty liver induced by administration of ethionine (an analogue of methionine) to cows in order to assess the relevance of PKC-dependent phosphorylation in the development of fatty liver. PKC activity was decreased in both the cytosolic and the total particulate fractions from fatty livers, compared to the corresponding fractions from control liver. The mode of activation by the PKC cofactors (1-oleoyl-2-acetyl-sn-glycerol, 12-O-tetradecanoylphorbol-13-acetate, phosphatidylserine and Ca²⁺) was similar in both control and fatty livers, suggesting a quantitative but not a qualitative change in PKC in fatty liver. At least three substrate proteins (34 kDa, 26 kDa and 19 kDa) were found in the cytosolic fraction and their phosphorylation was reduced in fatty liver. These results suggest that impairment of the signal transduction pathway mediated by PKC is involved in the pathogenesis of fatty liver in cows.Abbreviations ATP adenosine triphosphate - EGTA ethylene glycol bis(-aminoethylether)-N,N,N,N-tetraacetic acid - NEFA non-esterified fatty acid - OAG 1-oleoyl-2-acetyl-sn-glycerol - PKC protein kinase C - PS phosphatidylserine - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis - TG triglyceride - TPA 12-O-tetradecanoylphorbol-13-acetate     

加热光纤法同步测定土壤水热参数误差分析

土壤水热参数是研究土壤水热传输的基本物理参数。当前热脉冲探针法（HPP）可同步测定土壤水热参数,但该方法仅限于在点尺度下测定。与其具有相同理论基础的加热光纤法（SPHP-DTS）,可将测定尺度增大至田间千米尺度,但其测定精度尚未得到有效验证。为了探知SPHP-DTS法的误差,本研究进行了SPHP-DTS法与HPP法测定土壤水热参数的对比试验。结果表明,以HPP为标准,加热光纤法测定热导率的精度RMSE为0.13 W?m-1?℃-1。SPHP-DTS法测定的热导率显著高于HPP法,主要原因在于加热光纤时产生的温度效应。通过热导率法测定土壤含水率时,在热导率测定误差的影响下,SPHP-DTS法的测定精度明显低于HPP法。SPHP-DTS法测定土壤水热参数的其他误差来源包括光纤与土壤之间多个界面的接触热阻、光纤的温度敏感性、噪音干扰以及温度梯度驱动下的水分迁移。本研究可为SPHP-DTS法提升土壤水热参数测定精度提供理论参考。     

South-Western blot mapping方法的建立及其应用于锥虫细胞核中DNA结合蛋白的观察

South-Westerm blot mapping是一种结合Western blotting和Southern blotting某些特点的方法.本文介绍用其成功地观察到锥虫核蛋白中DNA结合蛋白的情况,并对一个分子量在40000左右、于较严谨条件下与DNA结合的核蛋白进行了特性鉴定.该蛋白等量地存在于锥虫的前循环期和血液期,对双链DNA有较大的亲和力,并能与酵母菌复制起始片段结合.本文还介绍了锥虫细胞核的提取技术和核蛋白的制备技术.     

Characterisation of energy-dependent efflux of imazalil and fenarimol in isolates of Penicillium italicum with a low,medium and high degree of resistance to DMI-fungicides

Differential accumulation of [¹⁴C]imazalil and [¹⁴C]fenarimol by germlings of wild-type and DMI-resistant isolates ofPenicillium italicum was studied at various pH values. At pH 7 and 8 the low-resistant isolate E_300–3 accumulated 22% and 35%, respectively, less imazalil than the wild-type isolate W₅. Imazalil accumulation at pH 5 and 6 was similar. Isolate E_300–3 also accumulated less fenarimol as compared with the wild-type isolate. This difference was much more obvious than for imazalil and was observed at all pH values tested. Differences in accumulation of both imazalil and fenarimol between low (E_300–3), medium (H₁₇) and high resistant (I₃₃) isolates were not observed. These results suggest that decreased accumulation of DMIs is responsible for a low level of resistance only and that additional mechanisms of resistance might operate in isolates with a medium and high degree of resistance. With all isolates fenarimol accumulation was energy-dependent. This was not obvious for imazalil.The wild-type and DMI-resistant isolates had a similar plasma membrane potential as determined with the probe [¹⁴C]tetraphenylphosphonium bromide ([¹⁴C]TPP⁺). Various test compounds, among which ATPase inhibitors, ionophoric antibiotics and calmodulin antagonists, affected the accumulation of [¹⁴C]TPP⁺, [¹⁴C]imazalil and [¹⁴C]fenarimol. No obvious correlation between the effects of the test compounds on accumulation levels of the fungicides and [¹⁴C]TPP⁺ could be observed. These results indicate that the plasma membrane potential does not mediate the efflux of DMI fungicides byP. italicum.     

新鲜蔬菜硝酸盐含量测定的改进试粉法

 为适应新鲜蔬菜硝酸盐快速检测的需要, 在现有试粉法的基础上对硝酸盐测定的试粉法进行了改良研究。结果表明, 本研究建立的直接以去离子水浸提蔬菜匀浆, 混合试粉配方为柠檬酸∶一水硫酸锰∶无水对氨基苯磺酸∶N - 1 - 萘乙二胺盐酸盐∶细锌粉= 30∶4∶1.6∶0.8∶1, 其加入量为0.1 g的改进试粉法, 对于溶液中硝酸盐含量在0～20 mg/L范围时, 显色吸光值与硝酸盐含量呈现良好的线性关系, 相关系数达0.9999, 方法回收率在97.7%～104.5%之间, 相对标准偏差2.71%。用本改进试粉法测定11种蔬菜的硝酸盐含量与国标法测定结果的t检验具有一致性。