采前CPPU处理对采后草莓品质及残留量的影响

以"甜查理"草莓果实为试材,采用盛花后喷施不同浓度(0.0、2.5、5.0、10.0、20.0mg·L~(-1))CPPU溶液,研究了CPPU处理对成熟草莓残留量及草莓单果质量、糖、酸、维生素C、单宁、水解氨基酸等品质的影响。结果表明:施用CPPU后,草莓单果质量和固酸比均高于对照(CK),5.0mg·L~(-1) CPPU溶液处理时达到峰值;草莓可滴定酸含量均低于对照,5.0mg·L~(-1)CPPU溶液处理达到最低值,且与对照差异显著(P0.05);草莓可溶性总糖、果糖、葡萄糖、维生素C含量的变化趋势均为低浓度CPPU处理(5.0mg·L~(-1)和2.5mg·L~(-1))会增加其含量,高浓度会降低其含量;单宁含量于5.0mg·L~(-1)处理达到最低值,其变化趋势与维生素C相反;水解氨基酸总量呈下降趋势,必需氨基酸含量略有升高。说明施用低浓度CPPU(不超过5.0mg·L~(-1))可以提高草莓果实的风味口感和部分营养品质,而高浓度会降低草莓果实的风味和品质;所有处理中仅有20.0mg·L~(-1)的CPPU处理有残留检出,且含量低于最高残留限量0.03mg·kg~(-1)(美国EPA),表明CPPU施用浓度低于20.0mg·L~(-1)处理草莓安全性较高。     

Detection of challenge virus in fetal tissues by nested PCR as a test of the potency of a porcine parvovirus vaccine

To estimate the potency of a porcine parvovirus (PPV) vaccine, three vaccinated and three non-vaccinated pregnant gilts were infected with PPV and the distribution of the virus was studied in the tissues of their 51 fetuses. Virus detection was attempted using haemagglutination (HA) and immunofluorescence (IF) assays, as well as by standard (single) and nested polymerase chain reactions (PCR). None of the detection methods yielded positive results when used to test for the presence of virus in suspensions of organs from the fetuses from the vaccinated gilts. However, the virus was detected in the fetuses from non-vaccinated gilts as follows: HA was positive in 14 cases out of 23 (60.8%), IF in 16/23 (69.5%), standard PCR in 12/20 (60%), and the nested PCR in 19/23 (82.6%). Although the correlation among the results of various methods of virus detection was rather close (r<0.83), the sensitivity of the nested PCR was the highest, both when testing dilutions of PPV and when analysing the fetal organs. The nested PCR therefore provides a reliable approach for studies of virus distribution in fetal organs, with special reference to potency tests on vaccines.     

塑料大棚内黄瓜叶片露时的计算方法

1.采用单叶的能量平衡方法,建立大棚黄瓜叶片的露时模式。模式运行结果:结露期间的叶片温度计算值与测量值差异极不显著(|t|0.50,S=0.291,n=25);结露时间、露干时间和露时的计算值与观测值差异不显著(|t|0.40,平均差异分别为21、-6和-25分钟。2.根据叶湿频率与相对湿度的关系,得出大棚黄瓜叶片结露的临界相对湿度为93％。用此临界相对湿度估算露时,误差一般不超出1小时。     

柑桔臀纹粉蚧的研究

柑桔臀纹粉蚧在上海地区常规栽培管理的十字景天上一年发生3代,以受精雌成虫或产卵雌成虫越冬。本文报导了此虫的年生活史及各虫态的生活习性、发育进程与历期,并测得其卵的发育起点温度为11.49±0.53℃;有效积温为73.11±3.39日度。以15%铁灭克颗粒剂根施;40%氧化乐果10O倍液浇灌,防治效果在97%以上.     

甘蓝型油菜黄籽高含油量育种资源遗传多样性分析

以2份白菜型油菜为对照,用SRAP标记研究了57份甘蓝型油菜黄籽高油育种资源的遗传关系。在遗传相似系数0.682处,可将59份材料分为3类:两份白菜型油菜聚为一类;甘蓝型油菜除选系Y58单独聚为一类外,其他所有选系归为另一类,显示黄籽高油育种资源遗传基础较窄。在遗传相似性系数0.738处,又可将57份甘蓝型油菜分为6个亚类,其中53份材料归为两个大的亚类,系谱或亲缘关系较近的材料一般聚在同一亚类,且按系谱关系比地理来源划分明显,提示地理来源配制强优势黄籽高油杂交组合可靠性可能不如按系谱来源。     

An improved allele-specific PCR primer design method for SNP marker analysis and its application

ABSTRACT: BACKGROUND: Although Single Nucleotide Polymorphism (SNP) marker is an invaluable tool for positional cloning, association study and evolutionary analysis, low SNP detection efficiency by Allele-Specific PCR (AS-PCR) still restricts its application as molecular marker like other markers such as Simple Sequence Repeat (SSR). To overcome this problem, primers with a single nucleotide artificial mismatch introduced within the three bases closest to the 3'end (SNP site) have been used in AS-PCR. However, for one SNP site, nine possible mismatches can be generated among the three bases and how to select the right one to increase primer specificity is still a challenge. RESULTS: In this study, different from the previous reports which used a limited quantity of primers randomly (several or dozen pairs), we systematically investigated the effects of mismatch base pairs, mismatch sites and SNP types on primer specificity with 2071 primer pairs, which were designed based on SNPs from Brassica oleracea 01-88 and 02-12. According to the statistical results, we (1) found that the primers designed with SNP (A/T), in which the mismatch (CA) in the 3rd nucleotide from the 3' end, had the highest allele-specificity (81.9%). This information could be used when designing primers from a large quantity of SNP sites; (2) performed the primer design principle which forms the one and only best primer for every SNP type. This is never reported in previous studies. Additionally, we further identified its availability in rapeseed (Brassica napus L.) and sesame (Sesamum indicum). High polymorphism percent (75%) of the designed primers indicated it is a general method and can be applied in other species. CONCLUSION: The method provided in this study can generate primers more effectively for every SNP site compared to other AS-PCR primer design methods. The high allele-specific efficiency of the SNP primer allows the feasibility for low- to moderate- throughput SNP analyses and is much suitable for gene mapping, map-based cloning, and marker-assisted selection in crops.     

含硫氨基酸对獭兔生长及被毛发育的影响

本试验旨在通过测定生长及被毛发育相关指标,确定蛋氨酸及半胱氨酸在獭兔饲粮中的最优添加水平,并了解它们在影响獭兔生长及被毛发育方面的相互关系。选择同天出生的仔獭兔294只,以窝为单位随机分为7组,每组7个重复,每个重复6只。对照组獭兔饲喂基础饲粮(含半胱氨酸0.23%、蛋氨酸0.24%),试验组獭兔分别饲喂在基础饲粮中添加0.10%、0.25%和0.40%半胱氨酸或蛋氨酸的试验饲粮。饲养周期为初生到151日龄。结果表明:饲粮中添加含硫氨基酸提高了獭兔的150日龄体重及平均日增重,0.25%、0.40%组与对照组相比存在显著差异(P<0.05)。随着含硫氨基酸添加水平的增加,獭兔的料重比表现为下降的趋势(P>0.05),平均日采食量则表现为上升的趋势(P>0.05)。与对照组相比,0.25%和0.40%组换毛完成率和被毛密度显著或极显著提高(P<0.05或P<0.01),但0.25%与0.40%组间差异不显著(P>0.05)。从92日龄和151日龄被毛评分来看,獭兔被毛品质随含硫氨基酸添加水平的增加仅表现出提高的趋势,组间差异不显著(P>0.05)。上述各指标在蛋氨酸与半胱氨酸各对应水平间均无显著差异(P>0.05)。通过生长曲线拟合分析,在2种含硫氨基酸的添加水平内,添加水平仅改变獭兔的最大生长速度,而对成年体重的影响不大。由此得出,蛋氨酸与半胱氨酸对獭兔生长与被毛发育均具有促进作用,均以0.25%添加水平为最优,且促进效果几乎同等,等量半胱氨酸可以完全代替蛋氨酸。但是,仅通过添加含硫氨基酸不能显著地改变獭兔的表观被毛品质。     

日粮碘添加水平对断奶至2月龄生长肉兔生长性能和血清生化指标的影响

本试验旨在研究日粮碘添加水平对断奶至2月龄生长肉兔生长性能和血清生化指标的影响.选用80只平均体重为(780±50)g的35日龄断奶新西兰肉兔,随机分成4组(每组20个重复,每个重复1只兔),分别饲喂在基础日粮中添加0(对照)、0.1、0.5和2.5 mg/kg碘的试验日粮,预试期7 d,正试期23 d.结果表明:日粮碘添加水平对平均日增重(ADG)有显著影响(P<0.05),0.1和0.5 mg/kg组的ADG显著高于对照组(P<0.05).日粮碘添加水平对料重比(F/G)有显著影响(P<0.05),0.5 mg/kg组的F/G显著低于对照组和0.1 mg/kg组(P<0.05).日粮碘添加水平对血清常规生化指标影响不显著(P>0.05).日粮碘添加水平对血清免疫球蛋白A(IgA)含量有显著影响(P<0.05),0.5 mg/kg组的IgA含量显著高于其他各组(P<0.05).日粮碘添加水平对血清免疫球蛋白G(IgG)和免疫球蛋白M(IgM)含量无显著影响(P>0.05).日粮碘添加水平对血清三碘甲腺原氨酸(T3)含量有极显著影响(P<0.01),随着碘添加水平的增加,T3含量先升高后降低,当碘添加量为0.5 mg/kg时T3含量达到最大值.日粮碘添加水平对血清四碘甲腺原氨酸(T4)含量的影响不显著(P>0.05).综上所述,断奶至2月龄生长肉兔日粮中碘适宜添加量为0.5 mg/kg(基础日粮碘含量为0.22 mg/kg).     

无花果的桑天牛防治初步研究

桑天牛Apriona germari（Hope）在上海地区无花果果园中为害较严重,被害株率达89％;经2种农药的防治试验,均有较好的杀虫效果。