用SSR技术和混合取样方法估算玉米群体间的遗传距离

The factors affecting the binding characteristics of GBSS with starch granule were studied using a wheat (Triticum aestivum) cultivar Chinese Spring with different temperature treatments. After sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis, we got GBSS concentration by coomassie brilliant blue G-250(CBB G-250) method. The results showed that the temperature affected the binding of GBSS and starch granule. In 50–80℃, the concentration of GBSS unbound from starch increased with the temperature rising, which the maximal concentration was 11.361 μg mL^-1 at 80℃, while that was reduced when the temperature was 85–95℃. Furthermore, Mg²⁺ could also affect the quantity of GBSS unbound from starch. When Mg2+ concentration was lower than 1.75 mmol L^-1, the concentration of GBSS unbound increased. The lower Mg²⁺ concentration, the higher the concentration of GBSS unbound. However, when Mg²⁺ concentration was higher than 2.5 mmol L^-1, it could restrain GBSS unbinding. These results showed that GBSS bound starch granule by non-covalent bonds. The best GBSS extracting conditions were 55 mmol L^-1 Tris-HCl (pH 6.8), 0.75 mmol L^-1 MgCl₂, 2.3% SDS, 5% 2-ME and 10% glycerol, 15 min in boiling water, or 55 mmol L^-1 Tris-HCl (pH 6.8), 0.75 mmol L^-1 MgCl₂, 2.3% SDS, 5% 2-ME and 10% glycerol, 80℃ 30 min. The results are helpful to investigate 3-D structure of biological activated GBSS and mechanism of GBSS binding with starch granule.     

Transgenic Plants with Enhanced Resistance to the Fungal Pathogen Rhizoctonia solani

The production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi is an important component of the defense response of plants. The timing of this natural host defense mechanism was modified to produce fungal-resistant plants. Transgenic tobacco seedlings constitutively expressing a bean chitinase gene under control of the cauliflower mosaic virus 35S promoter showed an increased ability to survive in soil infested with the fungal pathogen Rhizoctonia solani and delayed development of disease symptoms.     

利用棉绳采集口腔液监测猪伪狂犬病方法的应用分析

为分析使用棉绳采集口腔液监测猪场伪狂犬病(PR)方法的科学性,本研究拟通过实验室水平、动物试验及临床应用3个方面对使用棉绳采集口腔液监测猪场PR这一方法开展应用分析。首先对采样条件进行优化,并通过模拟试验测定棉绳对伪狂犬病病毒(PRV)的释放能力,通过动物试验测定病毒感染后检出时间,最后对临床样品进行检测分析。结果表明:使用直径为1.0 cm的棉绳,在早上喂料前采集口腔液样品,采样时间为20~30 min,可采集到更能满足试验要求的口腔液。病毒释放能力测定显示,棉绳对PRV的释放能力为50%左右,使用棉绳采集口腔液可检测到1个TCID50/0.1 mL的病毒含量。动物试验检测发现,猪群在感染后28 d中除第5天外,口腔液中病原含量均高于鼻拭子中病原含量,口腔液检测效果优于鼻拭子,且口腔液中病毒的检出时间(感染后第1天)早于血液中抗体转阳时间(感染后第7天)。临床样品检测分析结果表明,PRV疫苗免疫后也可通过口腔液检测到疫苗毒,并且存在无法通过口腔液检测感染PRV野毒后稳定猪中带毒的情况,因此口腔液检测方法应结合gE抗体检测,才可综合判断猪群是否为感染群体。综上,本研究优化了口腔液采集方法,并测定了棉绳对口腔液的释放能力和感染后检出时间,表明口腔液可作为较好的监测猪群PR的手段;口腔液监测方法需结合gE抗体检测来综合判断猪群是否为感染群体。     

Cross-fostering in coyotes: Evaluation of a potential conservation and research tool for canids

Cross-fostering has been attempted opportunistically with endangered canids as a means of increasing populations. Due to the usefulness of cross-fostering for conservation, an understanding of factors influencing success rates is essential. Using captive coyotes (Canis latrans) as a model, we assessed the willingness of adult pairs to foster young born to other parents. We assessed the efficacy of fostering pups into existing litters (augmentation) and completely switching litters (replacement). We augmented four litters with two pups of similar age when pups were <7 days old. In addition, we replaced four entire litters when pups were <10 days old. We also augmented litters with pups 3-4 and 6-7 weeks of age. Survival, weight gain, and dominance status of pups were monitored for six weeks and compared to four control litters to determine success. All complete litter replacements were successful with survival rates among replaced pups (89.5%) similar to those of control litters (90%). For augmented litters, pup survival was dependent on the age at which fostering occurred. All pups fostered into 4 litters at <1 week of age survived beyond 6 weeks of age, two of three fostering attempts with 3-4-week-old pups succeeded, while neither of two attempts to foster 6-week-old pups succeeded. Surviving fostered pups appeared to be at no disadvantage. Weight gains were similar for pups in all treatments, and there was no evidence of reduced dominance status among fostered pups as compared to natal pups in the same litters. These results illustrate that genetic relatedness is not essential for successful fostering and does not appear to alter dominance patterns; however the age at which pups are fostered may affect the success of fostering attempts.     

The G locus in Petunia hybrida Vilm: negative relationship to endogenous chlorophyll,starch and sugar

Suumary Three sets of Petunia hybrida Vilm. breeding lines with each set comprised of three genotypes, multiflora (gg), grandiflora (GG), and the heterozygote (Gg) were used in biochemical analyses to determine the possible mode of action of alleles at the G locus and their pleiotropic effects. Chlorophyll extractions did not correlate with visual observations that seedlings of the gg genotype have darker green foliage than seedlings of the GG genotypes. Likewise, chlorophyll, starch and sugar content were not related to greater seedling vigor, an apparent pleiotorpic effect to the g allele. Inconsistent differences in total soluble sugars and starch content were found with respect to the three genotypes. A qualitative difference in leaf sugar profiles as revealed by thin-layer and gasliquid chromatography separation was found. The Gg and gg genotypes consistently exhibited two extra bands at R_f 0.01 and at 0.52 to 0.56 which were absent in extracts from the GG genotype. The unknown compounds did not co-chromatograph with several sugar standards.     

Sheep immunoglobulins and their transmission to the neonatal lamb

Extract

In the past decade great strides have been made in clarifying the types of immunoglobulins found in various species of domestic animals. This review summarizes the information presently* * This review cites material published up to the end of 1976. available on sheep immunoglobulins — their classes, quantity and distribution in serum and colostrum. the review also highlights recent studies of fetal immunological competence, presucking lamb serum immunoglobulins, the process by which colostral immunoglobulins are passively transferred to the neonate, and the effects both of colostrum administration and deprivation on the newborn lamb.     

Ac/Ds转座子系统及其在玉米突变体库构建中的应用

Ac/Ds转座子系统是研究玉米功能基因组学的重要工具。Ac/Ds转座子系统以其在基因组中的低拷贝、倾向插入基因外显子、可以在同一基因不同位点造成突变等独特优势,在构建玉米突变体库和进行基因功能鉴定方面具有重要应用前景。综述了Ac/Ds转座子系统的插入特点、转座机制、在玉米突变体库构建中的应用以及我国玉米突变体库的现状,并对我国玉米Ac/Ds突变体库的研究提出展望。