小麦品种抗条锈菌小种专化性估测方法的研究

 在田间设置6品种×4小种组合的小麦条锈病隔离接种试验小区,成株期同步测定了各组合的组织学病变特征数值,包括侵入率、菌落面积、坏死面积、单菌落吸器个数和流行学特征数值,包括相对侵染点数、潜育期、病斑面积、产孢面积、孢子堆密度、病害传播速度和流行速度。计算了各品种,各项特征值的小种间变异系数和品种-小种互作方差贡献率并比较了在抗病性鉴定中利用它们估测小种专化性和非小种专化性的效果。在此基础上进行了多项指标间的相关分析。建议今后在抗病性类型鉴定中,将观察项目简化为镜检坏死面积比、单菌落吸器数或调查侵染几率、孢子堆密度等并计算这些数据的小种间变异系数来定量评价抗病性的小种专化程度。     

Modeling the egg and larval transport pathways of the Antarctic toothfish (Dissostichus mawsoni) in the East Antarctic region: New insights into successful transport connections

The Antarctic toothfish (Dissostichus mawsoni) is an important fishery species widely distributed in the Southern Ocean, especially in areas covered by sea ice. Understanding fish distributions and life cycles, including the transport and survival of eggs and larvae, is essential for the assessment and sustainable management of the fishery. However, owing to difficulties with in situ winter observations, information on the early life stages of D. mawsoni is lacking. Here, we investigated the transport pathways of fish eggs and larvae through a particle tracking study, using satellite-derived ocean surface velocities in the East Antarctic region, which includes important D. mawsoni habitats and exploratory fisheries. Our results indicate that particles released from continental slopes are more likely to be successfully transported to suitable settlement grounds than those released from the BANZARE Bank (the southern region of the Kerguelen Plateau), which is situated further north and has been hypothesized to be a potential spawning ground for D. mawsoni. This study demonstrates successful source–settlement connections in relation to ocean recirculation and suggests important settlement regions for D. mawsoni larvae in the East Antarctic region.     

基于牡蛎疱疹病毒DNA聚合酶基因的巢式PCR检测方法的建立及应用

为了建立适用于Os HV-1不同变异株的检测方法,在牡蛎疱疹病毒(Os HV-1)3个变异株全基因组序列比对的基础上,筛选到牡蛎疱疹病毒基因组中高度保守的DNA聚合酶(DNA polymerase)基因,据此设计巢式PCR引物,优化PCR反应体系和条件,建立了基于Os HV-1 DNA聚合酶基因的巢氏PCR检测方法(P-n PCR检测方法),利用P-n PCR与Cn PCR检测方法对不同年份和宿主来源的Os HV-1疑似感染样本进行检测。结果显示,Pn PCR检测方法能稳定地检出100拷贝/μL的病毒DNA;P-n PCR较C-n PCR检测方法具有更强的特异性和更高的检出率。研究表明,本研究建立的P-n PCR检测方法适用于Os HV-1不同变异株的检测,可为该病毒的检测和流行病学调查提供可靠的技术支持。     

Understanding the life histories of amphidromous fish by integrating otolith‐derived growth reconstructions,post‐larval migrations and reproductive traits

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Usage of electrolytic water system in the giant freshwater prawn,Macrobrachium rosenbergii (de Man) larval hatchery system

The purpose of this study was to use an electrolytic oxidizing (EO) water system in a prawn hatchery. The results of the EO water generation efficiency showed that available chlorine in the EO water increased as the salinity and electric power increased, but was reduced as the water flow rate increased. A bactericidal activity assay showed that the growth of six aquatic pathogens was well inhibited by incubation with EO water containing 1 mg L^?1 of available chlorine. The removal of NH₃‐N and NO₂‐N by electrolysis at 15‰ and 5 W had significant effects, and the removal rate of NO₂‐N was much faster than that of NH₃‐N. Prawn zoea (Z) reared in EO water with different levels of available chlorine at 0 (control), 0.2, 0.3 and 0.4 mg L^?1 had mortalities of 0%, 12%, 27% and 42%, respectively, after 72 h. However, Z were able to well survive in activated carbon‐treated EO water for 1 week. For the on‐farm use of the EO water system in a prawn hatchery, larvae in the EO water group had faster development and higher survival than those in the activated carbon group. From these results, we believe that the EO water group had excellent water quality and lower bacterial counts resulting in increased larval development and survival.     

鸭疫里默氏杆菌实时荧光定量PCR快速检测方法的建立与应用研究

根据GenBank登录的鸭疫里默氏杆菌外膜蛋白(OmpA)基因保守区序列,设计引物和探针,建立了直接检测鸭疫里默氏杆菌的实时荧光定量PCR快速方法。10倍梯度稀释RA菌株制备DNA模板测定方法的灵敏度,结果可在8.0×103CFU/mL浓度下特异地检测出目的菌,最低能检测到RA的DNA模板为8.0拷贝/μL;对鸭源大肠杆菌、多杀性巴氏杆菌、沙门氏菌、变形杆菌、金黄色葡萄球菌进行检测,结果均为阴性,建立的实时荧光定时PCR方法特异性强。用RA菌株人工感染雏鸭,感染后定时采集咽喉拭子、泄殖腔拭子、心血、肝脏、肺脏、脑,分别用实时荧光定量PCR检测,对脏器进行病原菌分离。结果表明,1/10半数致死量接种组,感染后8 h从心血、肝脏、脑组织检测到RA核酸,16 h后全部试样呈阳性;24 h首先从肝脏分离到RA,心血、肝脏、肺脏、脑组织均分离出RA。心血和脏器RA实时荧光定量PCR阳性检出率为63.8%(51/80),RA分离率为28.8%(23/80)。10个半数致死量接种组,1 h即可从咽喉拭子、心血和肝检测到RA核酸,5 h全部样品为阳性;5 h从肺和脑分离到RA。RA人工感染鸭的心血、肝脏、肺脏、脑实时荧光定量PCR阳性检出率为86.3%(69/80),RA分离率为60%(48/80)。用加热裂解法提取样品RA DNA只需30 min,建立的实时荧光定量PCR检测RA只需2 h,适用于RA的快速诊断、流行病学调查、种鸭引进隔离检疫、活鸭及其产品国内市场和进出口检验检疫。     

首乌蜜对家蚕幼虫寿命的影响

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Evaluation of Drought-Related Traits and Screening Methods at Different Developmental Stages in Spring Barley

Despite intensive research and breeding efforts, the physiological and quantitative genetic bases of drought tolerance are still poorly understood. The comparison of results obtained from different sources is also complex, because different testing methods may lead to controversial conclusions. This report discusses various drought stress experiments (hydroponics and in soil) in which the plant tolerance was studied at different developmental stages. Tests were performed in the germination, seedling and adult plant stages on the parental lines of five well-known barley-mapping populations. The results suggest that drought tolerance is a stage-specific trait and changes during the life cycle. The effect of drought stress depended not only on the duration and intensity of water deficiency, but also on the developmental phase in which it began. To induce the same type of stress and to obtain comparable tolerance information from the replications, it is recommended that drought stress should be induced at the same growth stage. Correlations between the traits, commonly associated with improved drought resistance (high relative water content under stress, proline accumulation, osmoregulation) with stress tolerance indexes, are also presented, while the advantages and disadvantages of the most frequently used screening methods are discussed.     

Corynebacterium pseudotuberculosis infection in goats. I. Evaluation of two serological diagnostic tests

The bacterial agglutination test (BAT) and the hemolysis inhibition test (HIT) were employed and evaluated.The threshold value between positive and negative antibody titres in BAT and HIT was determined on the basis of titration results for sera from 25 adult goats infected with Corynebacterium pseudotuber-culosis (positive), and sera from 25 adult goats from a herd in which caseous lymphadenitis did not occur (negative).Antibody titres were expressed as logio to the reciprocal value of the highest positive serum dilution in both tests. Positive titre (T) in BAT was stipulated as T ≥ 2.1 and in HIT as T > 0.6. The sensitivity and specificity was 0.96 in both tests in the material used. Twenty-three of the 25 goats infected with G. pseudotuberculosis were positive in both BAT and HIT.The reproducibility in both tests was described by the use of correlation coefficient and coefficient of variation. The values were estimated using duplicate determination of titres of 155 serum samples. Correlation coefficients were 0.87 for BAT and 0.95 for HIT. Coef-ficients of variation were 26.4 % for BAT and 14.1 % for HIT. The coefficient of variation was related to titres. It was highest for BAT at low titres.It was concluded that both tests can be used for seroepidemio-logical investigations of C. pseudotuberculosis infection in goats.     

Quantifying habitat specificity to assess the contribution of a patch to species richness at a landscape scale

Assessing and predicting the species richness of a complex landscape remains a problem because there is no simple scaling function of species richness in a heterogeneous environment. Furthermore, the potential value of an area for biodiversity conservation may depend on which, rather than how many, species the area contains. This paper shows how we can objectively evaluate the contribution of an area, e.g., a habitat patch, to larger-scale plant species richness, e.g., a landscape composed of patches of several habitat types, and how we can test hypotheses that attempt to explain this contribution. We quantified the concept of habitat specificity to assess the proportion of each observed plant population that is concentrated within a given spatial element. A case study of a biodiversity-monitoring program in the Swiss Canton of Aargau showed that the relative contribution of the three main types of land use to the overall species richness differed strongly between higher taxa (vascular plants and molluscs). However, the type of data, i.e., presence-absence or abundance, was not important. Resampling of the plant data suggested that stratification provided an unbiased estimate of relative specificity, whereas unstratified sampling caused bias even for large samples. In a second case study of vascular plants in an agricultural landscape in central Switzerland, we tested whether the type, size or shape of a landscape element can predict its contribution to the species richness of the landscape. Habitat types that were less frequently disturbed contributed more per m² to landscape species richness than more frequently disturbed ones. Contrary to expectation, patch size was negatively correlated to specificity per m² for arable fields, whereas patch shape appeared to be unrelated to the specificity per m² both for arable fields and for meadows. The specificity approach provides a solution to the problem of scaling species richness and is ideally suited for testing hypotheses on the effect of landscape structure on landscape species richness. Specificity scores can easily be combined with measures of other aspects of rarity to assess the contribution of a spatial element to conservation goals formulated at regional, national or global level.