木质素磺酸盐碱性过氧化氢降解及结构表征

通过表征受碱性过氧化氢降解的木质素磺酸盐,探索高效低耗的木质素降解条件。木质素磺酸盐与含有H2O2的0.5、1.0、2.0 mol/L的NaOH溶液分别在90、170℃下反应2 h。结果表明:碱性过氧化氢处理后木质素磺酸盐的Mw(重均相对分子质量)和Mn(数均相对分子质量)降低,而在170℃,1 mol/L NaOH溶液条件下获得最大程度的降解。木质素磺酸盐的相对分子质量在降解后分布相对集中,这表明木质素磺酸盐可直接用于开发木质素基材料而无需进一步分离。用碱性过氧化氢降解后,甲氧基摩尔分数降低。在170℃、2 mol/L NaOH溶液条件下4步加入过氧化氢,降解得到的木质素甲氧基摩尔分数下降57.4%。碱性硝基苯氧化的结果也表明在170℃下用2 mol/L NaOH溶液和4步添加H2O2处理后会得到最低的香草醛和香草酸产率,表明该条件下非浓缩的木质素结构被有效破坏。FTIR结果显示木质素的芳香结构消失。木质素磺酸盐利用碱性过氧化物降解,最佳条件是在2 mol/L NaOH溶液和170℃条件下,分4步添加H2O2。     

谷子杂交种与常规种光合和叶绿素荧光特性的比较

为了明确杂交谷的光合优势是否是其产量高于常规谷的一大主因,本研究于2013年对常规谷晋谷21号和杂交谷张杂谷5号的光合和叶绿素荧光特性进行比较。采用完全随机设计,每个品种种植5个小区,在拔节期和灌浆期分别测定各项光合指标。结果表明,在拔节期,张杂谷5号的净光合速率、PSⅡ实际光化学量子产量显著高于晋谷21号;但在灌浆期,张杂谷5号和晋谷21号之间的总叶绿素含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度、PSⅡ实际光化学量子产量、光化学淬灭参数和非光化学淬灭参数都存在显著差异。总体杂交谷在拔节期和灌浆期的光合性能高于常规谷。     

撕扯振动式嫩板栗脱蒲机设计与试验

针对国内板栗脱蒲机对成熟度60%~70%的嫩板栗存在的机器脱蒲分离率低、适应性差,容易损伤等问题,设计了一种撕扯振动式的嫩板栗脱蒲机。该机选用撕扯振动式脱蒲方法,利用先由锯齿形辊子对嫩板栗蒲进行撕扯和固定的沟槽式辊子揉搓,再由滚筒里柔性转动辊子上尼龙棒振动和圆筒上的柔性脱蒲棒的挤压联合作用对嫩板栗进行脱蒲。测试结果表明:该机采用的脱蒲方式新颖,能够最大限度地将嫩板栗蒲与板栗籽剥离,对于减轻栗农的劳动强度、缩短栗子从采摘到上市的时间发挥了极大的作用,值得进一步推广与普及。     

MeJA regulates enzymes involved in ascorbic acid and glutathione metabolism and improves chilling tolerance in loquat fruit

This study investigated the regulation of ascorbate acid (AsA) and glutathione metabolism and chilling tolerance by methyl jamonate (MeJA) in loquat fruit. The results showed that application of MeJA to loquat fruit inhibited the incidence of chilling injury manifested as internal browning (IB) and increased AsA and reduced glutathione (GSH) contents due to the inhibition of ascorbate oxidase activity and enhancement of monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase activities. Meanwhile, MeJA also enhanced activities of ascorbate peroxidase, glutathione peroxidase and glutathione-S-transferase. Our results suggested that MeJA can regulate the ascorbate and glutathione metabolism and has important roles in alleviating oxidative damage and enhancing chilling tolerance in loquat fruit.     

Variation of Color and Ray Pattern in Juvenile Shells in Hatchery‐produced Freshwater Triangle Pearl Mussels,Hyriopsis cumingii,in China

The variation and inheritance of juvenile shell color and pigmentation pattern in the freshwater mussel, Hyriopsis cumingii, were reported in 1‐yr‐old progeny of eight families. There were three distinctive phenotypes of shell color and pigmentation patterns observed, including a greenish‐brown shell with radial rays, yellowish‐brown shell with radial rays, and yellowish‐brown shell without radial rays. There were no greenish‐brown individuals without radial rays. The shell color phenotypes showed variation with the growth in juvenile Stage I (1–3 cm in shell length), and the percentage of individuals with radial rays increased once they reached a shell length of 11 mm and then stabilized after reaching 20 mm in shell length. Shell color differentiation became more apparent at a shell length of 26 mm. Results of chi‐square tests of the segregation ratio of shell color or ray phenotypes obtained from eight families at juvenile Stage II (6–9 cm in shell length) suggested that greenish‐brown is controlled by a dominant allele (G) and yellowish‐brown‐shell phenotype is by a recessive allele (y); the ray pattern phenotype is controlled by a recessive (r) and a dominant allele (R) at a single locus. Shell color phenotypes may be a useful genetic marker for future selective breeding of triangle pearl mussels.     

液相色谱-串联质谱法测定猪尿液中地西泮及其7种代谢物残留

为建立快速测定猪尿中地西泮及其7种代谢物残留的超高效液相色谱-串联质谱(UPLC-MS/MS)确证方法,本研究优化了样品净化的阳离子交换固相萃取柱(PCX柱)及其淋洗洗脱条件。猪尿液酸化后直接经PCX柱净化,依次用水、60%甲醇水溶液淋洗,最后用5%氨化甲醇洗脱;选用BEH C18色谱柱分离,UPLCMS/MS进行检测,以基质匹配标准曲线定量。结果显示:8种药物在0.3~20.0μg/L范围内具有良好的线性关系(R²≥0.995),检出限和定量限分别为0.1μg/L和0.3μg/L;各药物在3个添加浓度下回收率为73.6%~95.3%,日内、日间相对标准偏差分别为2.9%~18.6%(n=6)和2.2%~12.6%(n=3)。结果表明,本方法操作简单、快速,灵敏度高、特异性好。     

2020年宁夏吴忠市畜间包虫病流行病学调查

为了解宁夏吴忠市畜间包虫病流行范围及防治效果,科学规范指导下一阶段包虫病防治工作,2020年对吴忠市5个县(市、区)采用基本情况调查、实验室抽样检测等方法进行了畜间包虫病流行病学调查。共检测犬粪样品1 861份,犬细粒棘球绦虫感染阳性率为0.75%;抽检羊脏器4 027份,棘球蚴感染率为0.22%,有3个县区检出感染;检测牛脏器1 207份,棘球蚴感染率为0.17%,仅1个县检出感染。3个免疫试点县区中,同心县新生羔羊免疫率较低(36.18%),而羊棘球蚴感染率最高(0.66%)。统计分析显示,犬棘球蚴感染与牛羊感染呈正相关。结果表明,吴忠市畜间包虫病控制效果较好,但仍存在一定的棘球蚴感染,需要继续做好牛羊饲养管理和犬只驱虫,加强包虫病防治宣传,在重点地区大力推广包虫病疫苗免疫,逐步净化包虫病。本调查为该地区包虫病综合防治和净化提供了依据。     

固相萃取-超高效液相色谱法同时测定猪肉中22种磺胺类药物残留

为探索一次性检测猪肉中多种磺胺类药物残留的检测方法,建立了同时测定猪肉中22种磺胺类药物残留的固相萃取-超高效液相色谱方法。样品用3%乙酸乙腈提取,MCX固相萃取柱净化,水和甲醇淋洗,5%氨化甲醇洗脱,氮气吹至近干,0.1%甲酸-乙腈(9:1,V/V)溶液复溶,二极管阵列检测器270 nm检测。结果显示:该方法对22种磺胺类药物检测的线性关系良好(R2 0.999),定量限为2.5～10.0μg/kg,检测限为1.0～4.0μg/kg;各药物平均回收率为83.2%～96.6%,批内和批间变异系数分别为1.1%～3.5%和3.6%～13.4%。结果表明,该方法灵敏度高、重复性好、成本低廉,且操作简单、快速,可用于猪肉样品中多种磺胺类药物残留的同时检测。     

断奶仔猪日粮高剂量氧化锌的替代技术研究进展

氧化锌是断奶仔猪阶段饲料中防止腹泻的常用饲料添加剂,但是它的使用会造成环境污染。农业农村部也逐渐开始对氧化锌在养猪生产中的使用加以限制。此次研究从氧化锌的抗腹泻机理、不同的锌源和改变氧化锌的生物活性、氧化锌来源、植物乳杆菌、植物精油、水解单宁(HT)和氧化锌联合使用、猪免疫球蛋白G(pplgG)等方面进行综述,探讨其替代思路,以期为断奶仔猪高剂量氧化锌替代提供参考。     

离心除精浆对提高冷冻精液品质的作用

采用离心洗涤法去除精浆后,对精液进行冷冻处理。发现:1、除精浆精子冻后的活率、Ⅰ类顶体率和精子畸形率与未除精浆组存在显著差异(P<0．05);2、除精浆使稀释后精液精浆中GOT和LDH活性明显升高(P<0．05)。从平衡后到解冻后各组GOT和LDH活性都呈上升趋势。但除精浆试验组比未除精浆试验组上升缓慢;3、除精浆试验组精子的穿卵率、卵内平均精子数都显著高于未除精浆试验组(P<0．05);4除精浆离心洗涤液用生理盐水和脱脂乳-卵柠液．两者之间无显著差异(P>0．05)。