甜樱桃花芽分化后期特征观察

通过品种比较、地区比较和人工环境模拟3个关联的试验设计,观察甜樱桃从落叶后至谢花后的花芽分化发育的特征,探求其南引试栽、结实困难的原因。结果表明,郑州的早红宝石、红灯和拉宾斯,烟台、郑州和金华的红灯,以及花芽分化期置于露地和日光温室中的早红宝石在多个物候期阶段的最终分化发育的基本特征一致。因此,造成甜樱桃南引试栽、结实困难的主要原因可能与生长季的花芽分化无关,不能仅限于与花前高温引发的胚珠、胚囊发育不良有关,低温累积量不足也是不可被忽视的因素。     

S-genotyping of 25 sweet cherry (Prunus avium L.) cultivars from the Czech Republic

Sweet cherry (Prunus avium L.) is a self-incompatible species. Determination of the S-genotypes of cherry cultivars is crucial for breeding and to select appropriate cultivars for cross-fertilisation and fruit set. In this study, we characterised the S-genotypes of 25 sweet cherry cultivars, some of which had being bred at the Research and Breeding Institute of Pomology (RBIP), Holovousy, Czech Republic, and others were European cultivars in the RBIP collection. S-genotyping was carried out by polymerase chain reaction using consensus primers for the S-RNase and SFB genes, and capillary electrophoresis. Nine different known S-haplotypes (S₁, S₂, S₃, S₄, S₅, S₆, S₉, S₁₃, and S₁₆) were identified and the cultivars were assigned to 12 incompatibility groups. One local cultivar, ‘Pta?ka z Plzně’, originated from a wild forest seedling and used as a pollinator, was assigned to Group 0 of universal donors. The pedigree of some cultivars was confirmed by their S-genotype. This study represents the ?rst comprehensive S-genotype screening of sweet cherry genetic resources in the Czech Republic and will be useful for the design of crossing programmes and orchard management of these sweet cherry cultivars.     

日光温室条件下甜樱桃授粉受精期间环境因子对花粉行为的影响

以甜樱桃(Prunus avium L.)红灯为试材,采用荧光显微技术研究了日光温室和露地条件下甜樱桃花粉行为的差异,并观察记载了授粉受精期间日光温室和露地环境因子的变化情况。结果表明,环境因子影响了甜樱桃的花粉行为,日光温室内花粉萌发和花粉管伸长速率明显落后于露地。日光温室条件下,授粉后6h花粉萌发,120h花粉管进入子房;而露地条件下,授粉后3h花粉萌发,72h花粉管进入子房。其中,气温是影响日光温室甜樱桃授粉受精进程延缓的主要环境因子。     

甜樱桃茎尖培养和快速繁殖研究

本文主要报道了中国北方地区主栽的‘纳翁’、‘早丰’、‘红灯’、‘红蜜’、‘早紫’、‘红艳’和‘大紫’7种甜樱桃茎尖的适于分化培养基、增殖培养基和嫩茎生根的培养基。适于试管苗移栽的气温为15℃左右。培养过程中减少多酚化合物的氧化,可提高茎尖分化率达90％以上。     

Newly developed primers for the detection of Mycobacterium avium subspecies paratuberculosis

Recent publications reported the existence of IS900 like sequences in mycobacteria different from Mycobacterium avium subspecies paratuberculosis (Map). The primers used for IS900 detection of Map have amplified these sequences causing false positive results. In this study, we have developed two new PCR assays for the detection of Map. The first assay is based on the IS900 sequence using primers different from the ones previously reported, the second assay on the f57 sequence. The specificity of the tests was checked by analysis of 190 mycobacterial isolates (74 Map and 116 non-Map isolates). All Map strains were positive and all non-Map strains were negative. Serial dilutions of Map bacteria were used to assess the sensitivity of the assays. We achieved a sensitivity of 1 CFU per PCR for both assays. In addition, a PCR-simulating computer programme was used to evaluate the specificity of the new IS900 primers.

The combination of the two PCR assays has proven to be useful for the identification of Map but validation on a large range of clinical samples still needs to be done.     

Prevalence and distribution of paratuberculosis (Johne's disease) in cattle herds in Ireland

A simple random survey was conducted in Ireland during 2005 to estimate the ELISA-prevalence of paratuberculosis, commonly called Johne's disease (JD), in the cattle population. Serum samples were collected from all 20,322 females/breeding bulls over 12 months-of-age in 639 herds. All samples were tested using a commercially available absorbed ELISA. The overall prevalence of infected herds, based on the presence of at least one ELISA-positive animal, was 21.4% (95% CI 18.4%-24.9%). Herd prevalence levels amongst dairy herds (mean 31.5%; 95% CI: 24.6%, 39.3%) was higher than among beef herds (mean 17.9%; 95% CI: 14.6%-21.8%). However, the animal level prevalence was similar. The true prevalence among all animals tested, was calculated to be 2.86% (95%CI: 2.76, 2.97) and for animals >= 2 yrs, it was 3.30% (95%CI: 3.17, 3.43). For animals in beef herds, true prevalence was 3.09% (95%CI: 2.93, 3.24), and for those in dairy herds, 2.74% (95%CI: 2.59, 2.90). The majority of herds had only one ELISA-positive infected animal. Only 6.4% (95% CI 4.7%-8.7%) of all herds had more than one ELISA-positive infected animal; 13.3% (CI 8.7%-19.7%) of dairy herds ranging from two to eight ELISA-positive infected animals; and, 3.9% beef herds (CI 2.4%-6.2%) ranging from two to five ELISA-positive infected animals. The true prevalence of herds infected and shedding Mycobacterium avium subspecies paratuberculosis is estimated to be 9.5% for all herd types; 20.6% for dairy herds; and 7.6% for beef herds. If ELISA positive animals <2-years-of-age are excluded, the true herd prevalene reduces to: 9.3% for all herd types; 19.6% for dairy herds; and 6.3% for beef herds based on a test specificity (Sp) of 99.8% and test sensitivity (Se) (i.e., ability to detect culture-positive, infected animals shedding at any level) of 27.8-28.9%.     

中国甜樱桃病毒病及其检测技术研究进展

综述了近年来中国对甜樱桃(Prunus avium L.)病毒病及其检测技术的相关报道,介绍了中国甜樱桃上常见病毒的种类、危害及特性,主要包括:李属坏死环斑病毒(PNRSV)、李矮缩病毒(PDV)、苹果褪绿叶斑病毒(ACLSV)、樱桃锉叶病毒(CRLV)、樱桃病毒A(CVA)、樱桃绿环斑驳病毒(CGRMV)、樱桃小果病毒(LChV);阐述了甜樱桃病毒检测中所用的方法、技术,包括指示植物法(生物学鉴定法)、电子显微镜技术、血清学方法、分子生物学技术方法等.     

鸡胚胎性病原茵多重PCR检测方法的建立

为建立同时检测禽波氏杆菌(Bordetella avium)、沙门氏茵(Salmonella)、大肠杆菌(Escherichia coli)和绿脓杆菌(Pseudomonas aeruginosa)4种导致鸡胚死亡病原菌的多重PCR方法,本研究根据B.aviun的ompA基因、Salmonella的invA基因、E.coli的phoA基因和P.aeruginosa的toxR基因序列,各设计一对特异性引物进行多重PCR反应,并对反应体系和条件进行优化.结果显示,4对引物分别扩增出597bp、724bp、372bp和278bp的目的条带;并且特异性强不与其他非目的茵发生反应.经优化B.aviun、P.aeruginosa和E.coli多重PCR检测灵敏度达到104cfu/mL,而Salmonella为103cfu/mL.本研究建立的多重PCR方法为相关病原茵的快速检测提供方法.     

Detection of Mycobacterium avium subsp paratuberculosis in formalin-fixed paraffin-embedded intestinal tissue by IS900 polymerase chain reaction

OBJECTIVES: To evaluate and compare methods for DNA extraction from formalin-fixed, paraffin-embedded tissues and methods for detection of Mycobacterium avium subsp paratuberculosis by IS900 PCR for confirmation of Johne's disease in ruminants. DESIGN: A laboratory study. PROCEDURE: Three methods of DNA extraction of differing complexity and two PCR protocols using different pairs of IS900 primers were compared. Sensitivity and specificity were assessed using samples from ruminants with and without histological evidence of Johne's disease. RESULTS: The simplest method of DNA extraction, which involved two cycles of boiling and freezing followed by centrifugation, gave more consistent results than two methods that required solvent extraction of paraffin, proteinase digestion and DNA purification. The sensitivity of detection of M avium subsp paratuberculosis in paraffin blocks stored for 1 to 6 years from 34 cases of Johne's disease in sheep, cattle and goats was 88% for a 229 bp IS900 PCR assay and 71% for a 413 bp assay, using the detection of acid-fast bacilli by Ziehl Neelsen staining of histological sections from the same blocks as the gold standard test. PCR results correlated with the abundance of acid-fast organisms in the tissues. No false positive reactions were detected. CONCLUSION: PCR for identification of M avium subsp paratuberculosis in formalin-fixed, paraffin-embedded intestinal tissues from ruminants is a rapid and useful method. A simple method of sample preparation is effective. Amplification of short fragments of IS900 is more effective than amplification of longer fragments.