Dynamics of porcine circovirus type 2 infection in a herd of pigs with postweaning multisystemic wasting syndrome

OBJECTIVE: To determine the pattern of infection for porcine circovirus type 2 (PCV2) in a herd of pigs with postweaning multisystemic wasting syndrome (PMWS). ANIMALS: 29 sows and 250 pigs. PROCEDURE: Blood samples were collected from all 3-, 7-, and 12-week old pigs and 59 pigs at 28 weeks of age. Pigs that died during the study were necropsied. Porcine parvovirus and PCV2 antibodies were assayed. A polymerase chain reaction (PCR) was used to detect PCV2 genome in serum of selected pigs. RESULTS: The PMWS started when pigs were 8 weeks old, with a prevalence of 30% in 8- to 10-week-old pigs. Eighty-three pigs died during the period between 3 and 12 weeks of age. Microscopic lesions consistent with PMWS were observed, and PCV2 nucleic acid was detected (50 of 68 pigs). Antibodies to PCV2 decreased from 3 to 7 weeks of age, increased at 12 weeks of age, and were maintained until 28 weeks of age. One sow had a positive result for PCR of serum. Nine, 37 and 8 pigs had PCV2 genome in serum obtained at 7, 12, and 28 weeks of age, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with PCV2 coincided with severe clinical signs; however, infected 28-week-old pigs did not have evidence of disease. Immunity declined over time in young pigs. A long duration of PCV2 viremia was apparent in a high percentage of infected pigs, which may affect transmission and persistence of the virus in a herd.     

Effects of remifentanil on monophasic action potential and transmural dispersion of repolarization in rabbit myocardium

AIM: To study the effect of remifentanil on monophasic action potential and transmural dispersion of repolarization (TDR) in the 3-layer myocardium of isolated rabbit hearts. METHODS: Adult rabbits (n=18, 2.0 ~ 2.5 kg) were used to isolate the hearts for preparing Langendorff perfusion model. The hearts were randomly divided into 3 groups after perfusion with K-H solution for 15 min: the perfusion in control group (C group) continued for 60 min; the hearts in remifentanil group (R group) were perfused with 12 μg/L remifentanil K-H solution for 60 min; the hearts in remifentanil+aminophylline group (RA group) were given 60-min perfusion of 12 μg/L K-H remifentanil+30 mg/L aminophylline. The HR and 3 layers of myocardial monophasic action potential (MAP) in the left ventricular anterior wall were recorded at time points after balanced infusion for 15 min (T₀), and continued perfusion for 15 min (T₁), 30 min (T₂) and 60 min (T₃). The monophasic action potential duration of repolarization at 90% (MAPD₉₀) and the transmural dispersion of repolarization (TDR) were calculated. The early afterdepolarization, delay afterdepolarization and arrhythmia were also observed. RESULTS: In R group, slower HR and prolonger MAPD₉₀ and TDR at T₁~T₃ were observed as compared with those at T₀ (P<0.05). R group showed slower HR and longer MAPD₉₀ and TDR than C group and RA group (P<0.05). CONCLUSION: Remifentanil slows the HR, extends the MAPD₉₀ and increases the TDR, thus being prone to induce reentry. Aminophylline makes HR faster and MAPD₉₀ shorter, thereby reducing the TDR.     

Effects of perioperative saphenous and sciatic nerve blocks,lumbosacral epidural or morphine–lidocaine–ketamine infusion on postoperative pain and sedation in dogs undergoing tibial plateau leveling osteotomy

ObjectiveTo compare the quality of postoperative analgesia and sedation after preoperative saphenous and sciatic nerve blockade, preoperative lumbosacral epidural injection and perioperative intravenous (IV) morphine, lidocaine and ketamine infusions in dogs undergoing stifle arthroscopy and tibial plateau leveling osteotomy (TPLO) under general anesthesia.Study designProspective, blinded, randomized, clinical comparison study.AnimalsA total of 45 dogs weighing 33.9 (15.9–56.7) kg and aged 5.2 (1.0–12.0) years, mean (range), undergoing elective unilateral TPLO for spontaneous cranial cruciate ligament rupture.MethodsClient-owned dogs were enrolled. Dogs were randomly assigned to one of three groups: group MLK, perioperative IV morphine, lidocaine and ketamine infusion; group EPID, lumbosacral epidural with ropivacaine and morphine; or group SSNB, saphenous and sciatic nerve blockade with ropivacaine. Routine stifle arthroscopy followed by TPLO surgery was performed. Sedation and pain scores were assessed at 0, 2, 4, 8 and 24 hours following extubation. Rescue analgesia was administered as prescribed by Glasgow composite pain score–short form score >5.ResultsSedation scores for MLK were higher than EPID and SSNB. Pain scores for SSNB were lower than those for EPID and MLK. No significant differences were found in anesthesia duration or surgery duration among groups. No dogs required rescue analgesia.Conclusions and clinical relevanceAlthough analgesia was adequate in all groups, the best combination of analgesia without increased sedation was recorded for SSNB.     

玉簪组织培养及离体再生体快繁体系的建立

以玉簪品种"紫萼"嫩叶、叶柄、腋芽及幼嫩的花梗为外植体,利用植物组织培养技术,研究了不同外植体、培养基配方组成等因素影响下的愈伤诱导以及扩繁培养情况,建立玉簪组织培养体系。结果表明:最佳外植体为花梗,最佳培养基组成为MS+6-BA 2.0mg·L~(-1)+NAA 0.3mg·L~(-1)。     

Increased abundance of patatins,lipoxygenase and miraculins in a thaxtomin A-habituated potato Russet Burbank somaclone with enhanced resistance to common scab

Potato common scab caused by the actinobacterium Streptomyces scabiei is characterized by the formation of corky lesions on tubers that reduce their marketability. Management of common scab is very complex and often ineffective under various environmental conditions. Using potato varieties that are more resistant to common scab remains one of the most efficient strategies to control this disease. However, very little is known about the factors associated with resistance to common scab. Somaclone RB9 regenerated from thaxtomin A-habituated potato Russet Burbank calli produced tubers more resistant to common scab than the original variety. Comparison of the RB9 tuber proteome with that of Russet Burbank using label-free quantitative proteomic analysis revealed changes in the accumulation of defence-related proteins from the patatin and lipoxygenase (LOX) families, which are involved in the metabolism of lipids, and of two miraculins of the Kunitz-type protease inhibitors family. The implication of LOX during common scab infection was studied using synchronized minitubers developed from leaf-bud cuttings. S. scabiei infection stimulated the accumulation of LOX in both Russet Burbank and RB9 minitubers, but this accumulation was intensified in RB9 minitubers. Infection also increased LOX activity in Russet Burbank and RB9 minitubers. However, LOX activity measured in noninfected RB9 minitubers was similar to that of infected Russet Burbank minitubers, indicating endogenous activation of LOX activity in RB9 minitubers. We discuss how increased LOX abundance and activity in the somaclone RB9 may contribute to improving tuber defence against common scab.     

不同驱虫药驱虫后伊犁马血液生化指标变化的研究

[目的] 研究不同驱虫药对伊犁马血液生化指标的影响,为伊犁马科学驱虫及健康养殖提供参考。[方法] 将平均体重（265.5±35.6）kg、出生日期相近的40匹1岁伊犁马随机分为5组,每组8匹,分别为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组和试验Ⅳ组。在相同的饲养管理和日粮营养水平条件下,对照组不驱虫,在试验开始第1天,试验Ⅰ组使用伊维菌素驱虫,试验Ⅱ组使用吡喹酮驱虫,试验Ⅲ组使用阿苯达唑驱虫,试验Ⅳ组使用伊维菌素和阿苯达唑的混合药剂驱虫;在试验第14天采集马匹血液样品,测定血浆氮代谢指标、葡萄糖及酶相关指标、脂代谢指标及金属离子指标。[结果] ①试验Ⅲ组总蛋白（TP）浓度最低,与对照组、试验Ⅰ组、试验Ⅱ组及试验Ⅳ组相比,分别降低了8.16%、7.15%、4.98%及6.62%（P>0.05）。对照组及各试验组白蛋白（ALB）、尿素（UREA）浓度均无显著（P>0.05）差异。与对照组相比,试验Ⅲ组及试验Ⅳ组血浆中UREA浓度分别降低了33.15%及36.10%（P>0.05）。②与对照组相比,试验Ⅰ组、试验Ⅱ组、试验Ⅲ组、试验Ⅳ组丙氨酸氨基转移酶（ALT）活力分别降低了26.51%、21.11%、47.14%及52.38%（P>0.05）。试验Ⅲ组血浆中碱性磷酸酶（ALP）活力低于对照组,降低了0.19%（P>0.05）。与对照组相比,试验Ⅱ组和试验Ⅳ组的乳酸脱氢酶（LDH）活力显著（P<0.05）升高,分别提高了17.84%、13.51%;谷草转氨酶（AST）活力分别提高了5.40%和4.08%（P>0.05）。③对照组血浆中甘油三酯（TG）、肌酐（CREA）及尿酸（UA）的含量与各试验组相比均无显著（P>0.05）差异。试验Ⅰ组及试验Ⅳ组血浆中CREA浓度较对照组分别提高13.38%和9.86%（P>0.05）。试验Ⅱ组血浆中胆碱酯酶（CHE）活力显著（P<0.05）高于试验Ⅲ组,提高了17.70%。④对照组血浆中Mg²⁺浓度与各试验组相比差异不显著（P>0.05）;试验Ⅲ组血浆中Ca²⁺浓度最低,与对照组、试验Ⅰ组、试验Ⅱ组及试验Ⅳ组相比,分别降低了23.44%、16.40%、25.89%及21.43%（P<0.05）。[结论] 综合来看,使用伊维菌素和阿苯达唑混合驱虫,对伊犁马血浆中的氮代谢、糖脂代谢指标及肝功能代谢酶活力改善效果更明显。     

曲拉通和硝酸混合溶液直接提取快速测定草鱼中铅含量

为建立快速测定草鱼中铅含量的方法,通过分析曲拉通和硝酸混合溶液浓度、提取时间、称样定容体积比例等因素的影响,以及基体改进剂的使用效果,确定了草鱼中铅元素提取测定的最佳条件。验证结果显示：采用曲拉通和硝酸混合溶液提取草鱼中铅元素方法的提取率为86.5%～95.6%,加标回收率为91.5%～95.6%,精密度均小于4.0%,检出限和定量限分别为0.011和0.032 mg/kg,满足了国家标准GB 5009.12—2017第一法石墨炉原子吸收光谱法的要求。与国家标准方法比较,本研究建立方法的样品前处理时间从4～12 h缩短至0.2 h内,酸试剂用量从湿法消解的7～12 mL减少至1～2 mL;前处理过程无需高温消解,无需其他前处理设备,避免了样品污染和待测元素损失,实现了降低分析成本以及保护环境和试验人员的目的。结果表明,该方法是一种简单、准确、绿色、快速测定草鱼中铅含量的方法,尤其适合大量样品检测。     

不同居群垂穗披碱草种子生理生化、营养特性与其萌发时滞的相关性

【目的】揭示影响垂穗披碱草种子萌发时滞的关键因素。【方法】对不同居群野生垂穗披碱草种子的萌发时滞、生理生化特性、内源营养物质含量及其环境因子进行差异比较。【结果】居群P2种子萌发时滞最短,为6.0 d,P8萌发时滞最长,达到47.3 d。居群P5种子千粒重最大,为4.2 g,较千粒重最小居群P6高82.6%(P<0.05)。P8种子的脯氨酸（Pro）含量和过氧化氢酶（CAT）活性最高,分别较最低的P1和P4提高了517%和14.2%(P<0.05);P1的丙二醛（MDA）含量最低,较P7降低了34.9%(P<0.05),过氧化物酶（POD）活性和磷（P）含量最高,分别是P5和P4的3倍、4倍（P<0.05）;P3的电导率（Ec）值最低,较P6降低了43.1%,超氧化物歧化酶（SOD）活性最大,较P2提高12.8%(P<0.05);P5的可溶性糖和淀粉含量最高,分别较含量最低的P6和P1提高了87%、110%(P<0.05);P4的N含量最高,较P7提高了59.6%(P<0.05);P9的K含量最高,较P4提高了27.2%(P<0.05)。...     

自主式移动机器人定位坐标平滑算法研究

为了提高基于全局视觉导航的移动机器人的全局绝对定位精度，提出了一种适用于较大工作空间的摄像机参数分区标定方法，并借用数字图像中邻域的概念，定义了小区域的8—邻域关系，利用模糊数学的方法确定了中心区域及其邻域的权值函数，有效解决了各小区域边界的定位坐标平滑过渡问题。该平滑算法是一种计算模板，计算量不会因小区域的面积和小区域的个数的增加而增加，对于区域的内部和边缘计算一样有效。