沈阳市59年来气温变化及其突变性分析

利用沈阳市1951～2009年气温观测资料,采用线性倾向估计对沈阳市年平均气温、平均最高、最低气温的年际、年代际变化进行统计分析,并利用Mann-Kendall方法进行突变检测。结果表明,沈阳市年平均气温、最高、最低气温均呈上升趋势,其线性倾向率分别为0.231、0.181、0.218℃/10a;年平均气温、平均最高和最低气温的增温态势十分明显;平均最低气温的增温比平均最高气温更加显著。沈阳市年平均气温的突变点出现在1982年,年平均最高气温在1994年,年平均最低气温在1978年。     

鄂托克前旗近50年降水变化特征分析

本文利用鄂托克前旗1967-2018年气象观测站近50年的气象资料,对鄂托克前旗降水特征进行分析。结果表明：整体来说,鄂托克前旗的年降水量变化呈现微弱降低趋势,每10a大约减少1.2mm;28a时间尺度决定的主周期控制着该地区的年降水变化特征,通过周期和突变分析,预计未来三年左右降水高于多年平均值,随后的14年左右时间内降水量呈现减少趋势,逐渐低于多年平均降水量。     

Evolutionary characteristics of morbilliviruses during serial passages in vitro: Gradual attenuation of virus virulence

The genus Morbillivirus is classified into the family Paramyxoviridae, and is composed of 6 members, namely measles virus (MV), rinderpest virus (RPV), peste-des-petits-ruminants virus (PPRV), canine distemper virus (CDV), phocine distemper virus (PDV) and cetacean morbillivirus (CeMV). The MV, RPV, PPRV and CDV have been successfully attenuated through their serial passages in vitro for the production of live vaccines. It has been demonstrated that the morbilliviral virulence in animals was progressively attenuated with their consecutive passages in vitro. However, only a few reports were involved in explanation of an attenuation-related mechanism on them until many years after the establishment of a quasispecies theory. RNA virus quasispecies arise from rapid evolution of viruses with high mutation rate during genomic replication, and play an important role in gradual loss of viral virulence by serial passages. Here, we overviewed the development of live-attenuated vaccine strains against morbilliviruses by consecutive passages in vitro, and further discussed a related mechanism concerning the relationship between virulence attenuation and viral evolution.     

Canine leukocyte adhesion deficiency: presence of the Cys36Ser beta-2 integrin mutation in an affected US Irish Setter cross-breed dog and in US Irish Red and White Setters

Canine leukocyte adhesion deficiency (CLAD) is a primary immunodeficiency disease characterized by recurrent bacterial infections in the presence of marked leukocytosis. The disease was 1st described in the mid-1980s in a cross-breed Irish Setter Dog in the United States. It results from a defective beta-2 subunit of heterodimeric leukocyte adhesion proteins. The causative mutation for CLAD in Irish Setter Dogs from Europe has been identified as a missense mutation at base pair position 107 in the beta-2 integrin subunit gene (ITGB2) that results in an amino acid change from cysteine to serine at amino acid 36 (Cys36Ser) in the beta-2 integrin subunit protein. In the current work, the originally described dog with CLAD has been genetically tested and shown to have the same mutation as the European Irish Setters. This suggests that the mutation has been in the Irish Setter population for many generations spanning more than 2 decades. A related breed, the Irish Red and White Setter, has a history of interbreeding with Irish Setters and shares a common ancestry with the Irish Setter breed. DNA from Irish Red and White Setters residing in the United States was screened either by sequencing or by the newly developed restriction enzyme test for the Irish Setter Cys36Ser CLAD mutation. Seven of 54 dogs tested (13%) were found to be carriers of the Irish Setter CLAD mutation. Five of these were directly related to a sire from the UK, demonstrating the importation of an allele from another continent and establishing the need for genetic testing in this breed in the United States.     

ASIP基因编辑细毛羊自然突变和编辑基因型的遗传研究

为了探究控制毛色的多拷贝基因（ASIP）编辑细毛羊自然突变（D₉、D₅）和编辑突变的遗传特征和规律,分别将深棕色毛色表型的F₀代基因编辑中国美利奴细毛羊公羊与白色表型野生型母羊,有深色斑点表型的F₀代基因编辑母羊与野生型公羊交配,获得白色表型和深棕色及斑点状毛色表型F₁代个体23只。通过分析F₀、F₁代基因编辑羊ASIP基因的自然突变和编辑突变基因型,掌握编辑基因型的遗传规律和特征,以及自然突变、编辑突变与毛色表型的相关性。结果表明：F₀代基因编辑个体的4种主要编辑基因型（4 bp碱基缺失、5 bp,12 bp碱基插入、27 bp碱基缺失伴随1 bp碱基插入及2 bp碱基缺失）均在17只F₁代基因编辑羊得到遗传（另6只为野生型）。基因突变与毛色表型的相关性分析结果表明,D₉或D₅自然突变、ASIP基因编辑突变和拷贝数共同影响或决定基因编辑中国美利奴羊毛色图案的形成。     

60Co诱变方法选育高产多糖槐耳菌株

采用槐耳T菌株作为诱变材料,进行60Co射线的诱变试验（剂量为1000Gy,剂量率为10Gy·min^-1）,筛选出多糖含量高且适合栽培的新菌株T189,其多糖产量为37．13％,比槐耳T菌株（27．48％）提高35．1％。     

粤西籍人群Fv Leiden基因突变的初步调查

了解ＦｖＬｅｉｄｅｎ基因突变在广东籍正常人群中发生的情况。方法：用两种引物多聚酶链反应方法检测１３０例广东雷州籍正常人和３例静脉血栓患者ＦｖＬｅｉｄｅｎ基因突变情况，结果所有的样本均未检出ＦｖＬｅｉｄｅｎ突变。结论粤西籍正常人中尚未发现ＦｖＬｅｉｄｅｎ突变。     

Studies of Multi-Allelic Polymorphism of Dominant Dwarfing Genes in Wheat

Dwarfing breeding of wheat in the world is confined to the exploitation of recessive dwarfing sources. None of the dominant dwarfing sources discovered in common wheat (Triticum aestivum L. ) has found wide exploitation in wheat breeding due to the extreme dwarfness of their plants (20 -55 cm). We found in our work that some stable mutant lines with their plant height enhanced to different extents could be obtained in large populations derived from the stock seeds of the dominant dwarfing sources Aibian1 carrying Rht10 on 4DS and being 20 - 55 cm tall and Aisu2 carrying Rht3 on 4BS and being 55 cm tall, or from their descendants of induced mutation treatments, or from the segregating descendants of their crosses with mid- or tall-statured genotypes. Subsequently, we studied these mutation-derived lines differing in plant height with near isogenic lines and observed that the character of their enhanced plant height bred true, each carrying a semidominant dwarfing gene for a definite height and that as the plant height of the mutation-derived lines increased, the yield-contributing characters of their near isogenic lines were significantly improved. When test crosses with marker genes and physiological and biochemical genetic marker tests were performed to re-localize the semi-dominant dwarfing genes carried by the mutation-derived lines, it was confirmed that they shared common loci with Rht10 and Rht3 and that they were all mutation-derived multiple alleles. It is thus speculated that dominant dwarfing genes are of "multi-allelic polymorphism". In other words, dominant dwarfing genes, which are ultra-dwarfing, are liable to develop by mutation into a group of multiple alleles with plant height enhanced to different extents and some may have a height close to the ideal plant height for wheat breeding. Therefore, these results offer a fundamentally new approach for the exploitation of dominant dwarfing sources in wheat breeding.     

How to maintain improved cultivars

Improved cultivars loose their identity and healthiness unless maintained properly. Contaminating and degrading forces, such as outcrossing, volunteer plants, mixing, natural selection, mutation and seed-borne diseases, are at the root of this. Maintenance selection can prevent this deterioration. How it is carried out depends on the reproduction system of the crop. Crops are therefore classified into four categories; typical cross-pollinating crops, self-pollinating crops with a substantial amount of outcrossing, typical self-pollinating crops with little outcrossing, and the vegetatively reproduced crops. Generally some of the “breeder seed” is used to plant a small plot with spaced plants. A fair number of healthy plants of the cultivar type is selected and the seed is harvested per plant. The progenies of the selected plants are grown in small plots. Non-uniform or deviating plots and plots with a seed-borne disease are removed. The seed of the progenies that are healthy, uniform and similar (and so of the cultivar type) are harvested per progeny to be tested next season on larger plots. The same selection is applied and only the seed of the progenies that are healthy, uniform and similar are harvested together to produce the “breeder seed”. The details of this maintenance selection vary with the reproduction system, the multiplication rate of the crop and the possibilities available to the breeder. Seven crops, potato, common bean, barley, wheat, faba bean, quinoa and maize are discussed here as they represent the different reproduction systems and multiplication rates, while being important Andean food crops.