传染性胰腺坏死病毒VP3基因的分段表达及其抗原表位区域分析

采用PCR方法克隆了传染性胰腺坏死病毒(IPNV) VP3四段相互重叠的基因片段L1、L2、L3和L4,将PCR产物分别连接到原核表达载体pGEX-6P1和pET32a上,经酶切、PCR、测序鉴定,获得重组质粒pGEX-6P1 -VP3(L1)、pET32a-VP3( L2)、pGEX-6P1-VP3( L3)和pGE...     

Comparison of methods for assay of fecal proteolytic activity

Fecal proteolytic activity (FPA) in ten normal dogs was readily detected either calorimetrically using azocasein substrate or by radial enzyme diffusion into agar gels containing casein substrate. Daily FPA ranged from 17 to 207 azocasein units/g (ACUIG) or 4 to 18 mm of casein hydrolysis, while mean 3-day FPA ranged from 58 to 10 1 ACUIG or 7 to 15 mm. Studies of proteolytic activity remaining after treatment of fecal extracts with a specific trypsin inhibitor indicated that trypsin accounted for 0% to 71% of proteolytic activity. Proteolytic activity decreased steadily in fecal specimens stored at room temperature or above, but there was only slight loss in activity during storage for up to 5 days at 4 degrees C. Proteolytic activity was unaffected by repeated freezing and thawing and samples could be stored for long periods at -2 degrees C without noticeable loss of activity. It is concluded that assays of FPA using either azoprotein substrate or radial enzyme diffusion into agar gels containing casein substrate allow evaluation of exocrine pancreatic function in dogs, provided that several samples are tested. These methods are suitable for application in a variety of species.     

Protein-losing enteropathy in dogs is associated with decreased fecal proteolytic activity

Background: Measurement of proteolytic activity in feces is a traditional method for the diagnosis of exocrine pancreatic insufficiency (EPI). A drawback of this method is the occurrence of falsely low results that may lead to a false‐positive diagnosis of EPI. We hypothesized that intestinal loss of serum proteinase inhibitors in protein‐losing enteropathy (PLE) may inhibit fecal proteolytic activity and be a potential source of false low results. Objective: The objective of this study was to determine the effect of PLE on fecal proteolytic activity in dogs. Methods: Fecal proteolytic activity was measured using a radial diffusion casein digestion assay in 12 samples from 4 clinically healthy control dogs and 30 samples from 16 dogs with PLE. Gastrointestinal protein loss was assessed using an ELISA to determine fecal canine α₁‐proteinase inhibitor concentration. The relationship between the concentration of canine α₁‐proteinase inhibitor in the feces and the diameter cleared in the casein digestion assay was determined. The mean clearing diameter was compared between control dogs and dogs with PLE. Results: A significant negative correlation was observed between fecal canine α₁‐proteinase inhibitor concentration and casein clearing diameter (P < .001, Pearson r=—.6317, r 2 =.3999). Mean clearing diameter was significantly lower in dogs with PLE than in control dogs (12.63 vs 16.83 mm, P < .001, two‐tailed Student's t‐test). Conclusion: Increased fecal loss of α₁‐proteinase inhibitor in dogs with PLE is associated with a significant decrease in fecal proteolytic activity and may result in a false positive diagnosis of EPI.     

Infectious pancreatic necrosis in Atlantic salmon, Salmo salar L

A clinical and histopathological review was carried out of 21 outbreaks of acute infectious pancreatic necrosis (IPN) in Scottish Atlantic salmon, Salmo salar L., farms (13 marine and eight fresh water) during 1991-2004. A distinctive syndrome was evident in both post-smolts in sea water and fry in fresh water, where liver lesions, which had not previously been associated with IPN, became a consistent finding in addition to the more typical pancreatic and intestinal changes. Initial cases were described in post-smolts in Shetland, but by the end of the period of investigation this type of pathology had extended down the West coast of Scotland and into Ireland. Limited viral strain analysis suggested that similar strains were involved in both fresh water and sea water and that these differed from earlier isolates from rainbow trout, Oncorhynchus mykiss (Walbaum). In fresh water, recovered fish frequently developed a greatly distended intestine associated with accumulation of undigested food. In sea water, after the initial, often significant (50% or more), losses, there were many fish which failed to grow and became chronically emaciated and prone to sea louse infection. Although use of transfer diets containing immune enhancers and the selection of IPN resistant broodstock has reduced losses the disease remains a serious cause of economic loss.     

NBT-PABA test to assess efficiency and kinetics of substituted proteolytic enzyme action in pancreatic duct ligated minipigs

The NBT-PABA test is an established method for diagnosis of pancreatic exocrine insufficiency. In the present study the NBT-PABA test was used to test and compare the efficacy of two multienzyme preparations (product A and B) differing in galenic preparation in minipigs in which pancreatic exocrine insufficiency (PEI) was induced by pancreatic duct ligation. Without enzyme substitution no distinct increase in PABA was found in blood after oral administration of NBT-PABA. Administration of both enzyme preparations led to a clear dose dependent rise in PABA-concentrations in blood. Interestingly, the two preparations showed different time curves of serum PABA concentration, indicating differences in the kinetic of proteolytic enzyme action. It is concluded that the NBT-PABA test can be a very useful test for indirectly evaluating proteolytic enzyme efficacy in vivo, and also gives information about the kinetics of enzyme action, not only the end-result of enzyme action (like digestibility trials which were used traditionally). A single test is performed in a few hours and there is no need for fistulated animals.     

重组人组织激肽释放酶与猪胰腺组织激肽释放酶的理化特性比较

为了研究表达在蛋清中的重组人组织激肽释放酶(rhKl)是否与天然组织激肽释放酶具有相似的理化特性,对鸡输卵管暂态生物反应器表达的rhKl与猪胰腺组织激肽释放酶(pK)的理化特性进行比较鉴定.Western blotting检测结果显示,表达在蛋清中的rhKl能被人组织激肽释放酶(hKl)特异抗体识别,与pK无交叉反应,rhKl酶原和成熟酶的分子量约为43 kDa和37 kDa.理化鉴定结果显示,rhKl在pH7～10的范围内活性稳定,而pK在pH 8～9的范围内活性较稳定;rhKl和pK均能被Cu2+、Fe3+和Al3+完全抑制;rhKl和pK的热稳定性相似,但rhKl在37℃孵育20 min后被显著激活.以上试验结果表明,表达在蛋清中的rhKl分子量正确,理化特性与猪的天然酶相似,具有开发利用价值.     

猪胰多肽粗品对断奶仔猪生长及血清蛋白质浓度的影响

２８日龄的断奶仔猪３９头随机分为３组,每组１３头,Ⅰ组为对照组,每周每头颈部皮下注射１．０ｍＬ ＰＢＳ。Ⅱ组、Ⅲ级分别注射１．０ｍＬ不同浓度的猪胰多肽粗品,剂量分别为２、４ｍｇ／ｋｇ,观察猪胰多肽粗品对断奶仔猪生长、血清中总蛋白、白蛋白和球蛋白浓度的影响。结果表明：（１）试验结束时,各组间仔猪体增重无明显差异,但用猪胰多肽粗品处理的Ⅱ－Ⅲ组仔猪的料重比均低于对照组。（２）各组血清总蛋白含量随日龄增     

Inoculation of infectious pancreatic necrosis virus serotype Sp did not cause pancreas disease in Atlantic salmon (Salmo salar L.).

Atlantic salmon were selected from a fish farm with no previous record of pancreas disease (PD) or infectious pancreatic necrosis virus (IPNV) infection. Groups of fish were inoculated with either IPNV (strain Sp) from cell culture, organ material from fish with PD or control material as phosphate-buffered saline (PBS). Virological, histological and immunohistochemical examinations were carried out throughout the experiment. None of the fish died or showed clinical symptoms of PD. Histological examination revealed no pathological changes, and immunohistochemical studies were negative. Virus was isolated only sporadically from the group inoculated with organ material, whereas it was isolated consistently from the group inoculated with virus propagated in cell culture, as well as from in-contact control fish after the first week. In a latent carrier test, changes were entirely lacking in the first mentioned group, and were only slight in the last mentioned group. The data suggest that PD is not a transmissible disease, and that IPNV isolated from a PD outbreak does not play any part in the etiology of this disease.     

Ultrastructural studies on the pancreatic acini in duck (Anas boscas) and pigeon (Columba livia)

The aim of this research work was to study the histological structure of the pancreatic acini by transmission electron microscope in two avian species, duck and pigeon. The specimens were collected and processed for electron microscopic study. The results showed that the acini of the two avian species were two types; the first one was an electron dense and the second one an electron lucent. The light acinar cells were larger in size than the dark cells. These cells contained centrally located ovoid nuclei with prominent nucleoli and abundant euchromatin. The cytoplasm was electron lucent, with many rough endoplasmic reticulum, polymorphic mitochondria. Numerous zymogen granules were distributed in the basal part and around the nucleus, so these cells considered active cells. The dark acinar cells were characterized by an electron dense cytoplasm. The most prominent cell organelle in these cells were the zymogen granules that appeared in different sizes while other organelles as mitochondria, and rough endoplasmic reticulum were inconspicuous or few, so these cells were considered as inactive cells. The nucleus with indented nuclear membrane located centrally with prominent nucleoli and abundant heterochromatin. Prominent intercellular spaces between the individual acinar cells, as well as well-developed basement membrane separating the electron dense cells and the lumen contained the secretion between acinar cells. It could be concluded that the acinar cells in ducks and pigeons were divided into two types, that is, light and dark acinar cells which mainly attributed to the activity of these cells.     

禽胰多肽对粤黄公鸡生长的影响

98只18日龄的粤黄公鸡随机分为7组，第Ⅰ组为对照组，每周每只皮下注射PBS0.5mL，其中第Ⅱ-Ⅳ组每周皮下注射3、6和12μg/kg禽胰多肽（APP）纯品，第Ⅴ-Ⅶ组每周同部位分别注射6、12和24μg/kg的APP粗品，连续7次，结果表明；注射高剂量粗品APP可提高鸡的采食量，提高饲料转化率，提高鸡只胴体质量和全净膛质量，血中FT3含量升高，鸡只生长速度加快，而一定量的纯品APP实际情况可促进鸡只生长，但不明显。