火焰原子吸收光谱法测定奶粉中锌的含量

采用原子吸收光谱法测定多种品牌奶粉中锌的含量,对干法消化奶粉所用混合酸的组成、比例等试验条件进行了研究,其最佳样品处理条件为:硝酸-高氯酸(4+1)作为溶解用酸,1 mol/L盐酸作为定容用酸,测定结果的相对标准偏差小于2%.     

猪流感病毒多表位融合蛋白对小鼠的免疫原性分析

作者拟利用表位多肽的抗原性及黏膜佐剂免疫增强作用,设计可通过黏膜途径免疫接种的猪流感病毒通用型疫苗.体外合成H1N1、H3N2亚型猪流感病毒表位抗原基因,C末端串联大肠杆菌热敏性肠毒素LTb基因,构建pET30(a)-ep-LTb表达载体,利用SDS-PAGE、Western blot分析重组融合蛋白表达及生物学特性,小鼠免疫试验分析融合蛋白免疫原性.SDS-PAGE检测表达蛋白相对分子质量约38 ku,主要以包涵体形式存在.重组蛋白可与抗His-tag抗体和CTB抗体发生特异性反应.ELISA及HI试验检测,经黏膜途径免疫的小鼠产生了针对重组表位模拟抗原蛋白及H1N1、H3N2亚型猪流感病毒的血清抗体及局部黏膜分泌型IgA抗体.利用猪流感病毒表位抗原与LTb基因串连获得的融合蛋白具有良好的免疫原性和反应原性,且在黏膜接种局部产生理想的分泌型IgA抗体,能有效阻断病原由黏膜局部感染,为研制猪流感病毒通用型疫苗奠定了基础.     

Cutaneous lymphoma in a juvenile dog

Abstract: An 18-month-old male Doberman Pinscher was referred to the Veterinary Medical Teaching Hospital of the College of Veterinary Medicine for an erythemic nodular mass on the right forelimb. The mass was diagnosed as cutaneous lymphoma, based on cytologic examination of a mass aspirate and histopathology. Using immunohistochemistry the neoplastic cells were positive for CD3 but negative for CD79a, E-cadherin, and pancytokeratin, confirming their origin as T lymphocytes. No tumor recurrence was noted 18 months after surgery. To our knowledge, this is the first report of a solitary nodular form of cutaneous lymphoma in a young dog.     

Acid–Base Parameters and Steroid Concentrations in Pre‐Ovulatory Follicles and Plasma of Lactating Dairy Cows with Spontaneous and Synchronized Oestrus or Follicular Cyst

The study aimed to compare the acid–base balance and steroid concentrations between follicular fluids (FF) of pre‐ovulatory follicles derived from a spontaneous oestrus (SO), synchronized or induced oestrus (IO) and follicular cysts (CYS) and between FF and blood in dairy cows. Forty‐two dairy cows were included in this study. The animals were allocated to three groups: SO (n = 23); IO (n = 11) using GnRH at day 0 and day 9 and PGF₂α at day 7; and animals with CYS (n = 10). The follicular fluids (FF) were aspirated from the cyst/pre‐ovulatory follicles (? ≥ 15 mm) after SO and after second GnRH dose in IO by transvaginal ultrasound‐guided ovum pick‐up technique. Blood samples (BL) were collected in heparinized vacutainer tubes. The oxygen tension (pO2) in FF of IO was higher (p < 0.05) than in SO and CYS groups. There were negative correlations (p < 0.001, r = ?0.89) between FF and blood pO2. The carbon dioxide tension (pCO2) and lactate level in FF of CYS group were higher (p < 0.05) than in SO and IO groups. There were negative correlations (p < 0.01, r = ?0.73) between blood and FF pO2. Oestradiol‐17β concentration in pre‐ovulatory follicles and plasma of the SO group was higher (p < 0.001) than in IO and CYS groups. Progesterone concentration in pre‐ovulatory follicles and plasma of the SO and IO groups was lower (p < 0.01) than in CYS group. Plasma androstenedione concentration in SO and IO groups was higher (p < 0.05) than in CYS group. In conclusion, acid–base parameters, E2 and P4 levels in the follicular fluid of both IO and CYS groups were deviated greatly from the physiological level (disturbances of intrafollicular/intracystic environment), which may affect the quality of both the oocyte and the granulosa cells.     

Characterization of the diffuse mucosal associated lymphoid tissue of feline small intestine

Characterization of the feline intestinal mucosal associated lymphoid tissue (MALT) will facilitate investigation of intestinal disease in the cat and promote the cat as an animal model for a range of human diseases which involve the intestinal lymphoid tissue. This includes inflammatory bowel disease, viral and non-viral associated intestinal lymphomas and immunodeficiency associated syndromes. Morphologic and phenotypic characterization of the normal small intestinal diffuse MALT in 22 SPF cats was performed using flow cytometry and cytology on isolated intestinal leukocytes from the intra-epithelial and lamina proprial compartments, as well as immunohistology on tissues from the feline duodenum, jejunum and ileum. The intra-epithelial compartment (IEC) was dominated by lymphocytes (>85%) which frequently contained intracytoplasmic granules. The most striking findings in the IEC were the elevated percentages of CD8 alpha+ lymphocytes (40%), presumed to express CD8 alpha alpha chains, and CD4-/CD8- (double negative) lymphocytes (44%), and the consistent presence of a minor subpopulation of CD3+/CD11d+ IELs (6%). Small percentages of CD4+ lymphocytes (10%) were observed such that the IEL CD4:CD8 ratio (0.25) was low. The LPC also contained a majority of T cells and few plasma cells. However, this compartment had reduced percentages of CD8 alpha+ lymphocytes (28%) and increased percentages of CD4+ lymphocytes (27%) relative to the IEC. However, the LPL CD4:CD8 ratio (1.0) remained low compared with the ratio in peripheral blood. In feline MALT, MHC class II expression was lower than in other peripheral lymphoid compartments. The results of this study provide important reference values for future investigations involving feline intestinal lymphocytes and demonstrates that the leukocyte distribution and phenotypic characteristics of the feline diffuse MALT appear largely similar to the murine, rat and human counterparts.     

Detection and molecular characterization of porcine type 3 orthoreoviruses circulating in South Korea

Orthoreoviruses infect virtually all mammalian species, causing systemic infections including mild gastrointestinal and respiratory illnesses. However, little is known about the prevalence or genetic diversity of porcine orthoreoviruses in South Korea. We examined 237 diarrheic fecal samples collected from 78 pig farms around the country. RT-PCR utilizing primers specific for the L1 gene of mammalian orthoreoviruses showed that 45 (19.0%) samples were positive. The 10 strains isolated from orthoreovirus-positive samples formed typical perinuclear cytoplasmic inclusion bodies and had an atypical hemagglutination pattern; these are characteristics of type 3 orthoreovirus. Phylogenetic analysis of the S1 gene in these 10 Korean and other strains showed that type 3 orthoreoviruses could be divided into four lineages; the 10 Korean strains were included in porcine lineage IV, along with T3/porcine/Sichuan/2006. Sequence analysis showed that strains in lineage IV had nucleotide identities of 97.0-98.1% and deduced amino acid identities of 96.4-98.2%. Sequence analysis of the σ1 protein, a viral attachment protein, revealed that the amino acid sequences associated with neurotropism (amino acids 198-204, 249I, 350D, and 419E) were highly conserved among the Korean strains, confirming that neural tropism was present. In conclusion, our findings suggest that porcine orthoreovirus infections are endemic in pig farms in South Korea and that the 10 novel Korean porcine orthoreoviruses belong to porcine lineage IV of type 3 orthoreovirus. In addition, sequence analysis of S1 genes encoding the σ1 protein showed that the 9 of 10 Korean porcine orthoreoviruses exhibited neural tropism.     

A comparative study on the rumen microbial populations,hydrolytic enzyme activities and dry matter degradability between different species of ruminant

A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly (P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6‐diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep (P < 0.01). Goat had the highest (P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals.     

当代大学生就业中道德缺失问题的思考

大学生就业难是社会普遍关注的焦点问题之一。大学生就业中的伦理道德缺失不容忽视。要解决这一问题，除学校加强道德教育、企业提升自身魅力外，根本在于大学生自身的觉悟与个人素养的提高。