表达Ⅰ型鸭病毒性肝炎病毒VP1蛋白重组腺病毒的构建

为构建表达Ⅰ型鸭病毒性肝炎病毒(DHV-I)VP1蛋白的重组腺病毒,本实验采用RT-PCR方法扩增DHV-Ⅰ HP-1株VP1基因,克隆于腺病毒穿梭质粒pShuttle-CMV中,并将其电转化于含腺病毒pAdeasy骨架质粒的大肠杆菌BJ5183中,通过同源重组制备含有重组腺病毒的质粒.重组质粒经PacⅠ酶切线性化后转染AD293细胞,获得重组腺病毒(rAd-VP1).间接免疫荧光和western blot鉴定结果显示,DHV-Ⅰ的VP1蛋白在重组腺病毒感染的AD293中获得表达.rAd-VP1的制备为鸭免疫实验效果评价奠定了基础.     

Time-dependent changes of calbindin D-28K and parvalbumin immunoreactivity in the hippocampus of rats with streptozotocin-induced type 1 diabetes

The hippocampus is affected by various stimuli that include hyperglycemia, depression, and ischemia. Calcium-binding proteins (CaBPs) have protective roles in the response to such stimuli. However, little is known about the expression of CaBPs under diabetic conditions. This study was conducted to examine alterations in the physiological parameters with type 1 diabetes induced with streptozotocin (STZ) as well as time-dependent changes in the expression of two CaBPs changes of were being evaluated. Rats treated with STZ (70 mg/kg) had high blood glucose levels (>21.4 mmol/L) along with increased food intake and water consumption volumes compared to the sham controls. In contrast, body weight of the animals treated with STZ was significantly reduced compared to the sham group. CB-specific immunoreactivity was generally increased in the hippocampal CA1 region and granule cell layer of the dentate gyrus (DG) 2 weeks after STZ treatment, but decreased thereafter in these regions. In contrast, the number of PV-immunoreactive neurons and fibers was unchanged in the hippocampus and DG 2 weeks after STZ treatment. However, this number subsequently decreased over time. These results suggest that CB and PV expression is lowest 3 weeks after STZ administration, and these deficits lead to disturbances in calcium homeostasis.     

猪圆环病毒2型ELISA抗体检测试剂盒的研制及初步应用

用PCV2 Cap蛋白单克隆抗体预包被酶标板,将杆状病毒表达系统表达的PCV2 Cap蛋白作为检测用抗原,利用捕获包被法建立了间接ELISA法用于猪圆环病毒2型抗体的检测.通过优化ELISA条件,研制试剂盒并应用于圆环病毒2型疫苗的免疫效果检验.利用研制的试剂盒与IFA、商品化进口和国产同类试剂盒对178份猪血清进行平行检测,总符合率分别为96.63％、97.75％和84.27％,与其他几种常见猪病毒抗体阳性血清无交叉反应.试剂盒批内、批间变异系数分别为2.35％ ～4.06％和4.87％ ～ 6.54％,2～8℃保存15个月稳定,适合于对不同来源猪圆环病毒2型疫苗人工免疫猪血清抗体进行检测.     

鸽副黏病毒Ⅰ型(川沙株)的分离与鉴定

利用SPF鸡胚培养法从上海川沙某具有典型新城疫症状和病理变化的高死亡率发病鸽场的死亡鸽体内分离到一株病毒.对该病毒E5代尿囊液进行病原学鉴定、RT-PCR鉴定、理化特性测定、致病指数、病毒血清学试验及鸽体致病性试验,结果显示该病毒具有血凝性,且血凝特性可被新城疫病毒参考阳性血清所抑制,而不能被减蛋综合征病毒、禽流感病毒（H5、H9和H7）阳性血清抑制;该病毒对氯仿、乙醚和酸敏感;致病指数分别为：最小致死量鸡胚平均死亡时间为55.2 h,1日龄雏鸡脑内致病指数为1.8,6周龄雏鸡静脉致病指数为2.39.经鉴定,该分离毒株为鸽副黏病毒Ⅰ型强毒株,将其命名为鸽副黏病毒Ⅰ型（川沙株）.     

林窗理论在山地型城市森林建设中的应用前景

从森林循环演替、森林特殊的生境、边缘效应、森林植被物种多样性及森林景观格局多样性等方面论述了林窗干扰作用,并讨论了林窗理论在山地型城市森林建设中森林动态管理、森林景观格局优化和林相改造等方面的应用前景。     

Inhibitory action of intravenously administered ammonium acetate on the motility of the rumen in sheep

Summary

The effect of 60 minutes’ intravenous infusions, before morning feeding, of ammonium acetate (18.6 micromole/min/kg of body weight) and ammonium acetate with propranolol (11 μg/min/kg of body weight) on the ruminal motility of sheep was examined. Ammonia has an adrenaline‐like action therefore propranolol, a beta‐receptor blocking agent, was administered in order to eliminate the possible effect of adrenaline on ruminal motility. The contractions of the dorsal sack of the rumen were registered by means of the balloon method, with the gauge inserted through the rumen fistula. The infusion of ammonium acetate caused an increase of the ammonia concentration in the blood to 0.6 mmolel/at the end of 60 minutes’ infusion. Already during the first 5 minutes of the intravenous infusion of ammonium acetate there was a decreased frequency of ruminal contractions, which was observed throughout the infusion. After the infusion there was a radical decrease of the concentration of ammonia in the blood, and at the same time an increase in the frequency of rumen contraction was observed.

Blocking of the beta‐adrenergic receptors by propranolol did not eliminate the inhibiting action of ammonium ion on rumen motility. The infusion of the ammonium acetate caused an increase of adrenaline and glucose concentration. This response was eliminated by propranolol in the case of adrenaline but not glucose. It is assumed that the action of ammonium ion on the rumen motility is derived primarily by the central nervous system.     

Role of estrogen receptor-α (ESR1) and the type 1 insulin-like growth factor receptor (IGFR1) in estradiol-stimulated proliferation of cultured bovine satellite cells

Although the exact mechanism(s) by which estradiol (E₂) enhances muscle growth in a number of species, including humans and cattle, is not known, E₂ treatment has been shown to stimulate proliferation of cultured bovine satellite cells (BSCs). This is particularly significant because satellite cells are the source of nuclei needed to support postnatal muscle fiber hypertrophy and are thus crucial in determining the rate and extent of muscle growth. The objective of this study was to assess the role of estrogen receptor-α (ESR1) and the type 1 insulin-like growth factor receptor (IGFR1) in E₂-stimulated proliferation of cultured BSCs. To accomplish this, we have used small interfering RNA (siRNA) to silence expression of ESR1 or IGFR1 and assessed the effects on E₂-stimulated proliferation in BSC cultures. In BSCs treated with nonspecific siRNA, E₂ significantly (P < 0.05) stimulates proliferation under conditions in which neither IGF-1 nor IGF-2 expression is increased; however, treatment of ESR1- or IGFR1-silenced cells with E₂ does not significantly stimulate proliferation. These results indicate that both ESR1 and IGFR1 are required for E₂ to stimulate proliferation in BSC cultures. The fact that this occurs under culture conditions in which neither IGF-1 nor IGF-2 mRNA expression is increased strongly suggests that E₂ activates IGFR1 via a mechanism that does not involve increased IGF-1 or IGF-2 binding to the receptor.     

A COMPARISON OF TOOLS FOR PRUNING PINUS PINASTER

Dielectric heating by radio-frequency power has been established in various countries as a practical means for the rapid gluing of wood with thermosetting adhesives. The high-frequency drying of wood and wooden products as an economical substitute for conventional drying methods is being investigated extensively.

Especially in South Africa, it seems the appropriate time to consider this process again. This article is the first in a series and reviews the general principles. Further papers will present values of dielectric properties of South African pines and deal with the possibilities of drying wood by this process.