Genomewide association study reveals novel quantitative trait loci associated with resistance towards Septoria tritici blotch in North European winter wheat

Fungal diseases are a major constraint for wheat production. Effective disease resistance is essential for ensuring a high production quality and yield. One of the most severe fungal diseases of wheat is Septoria tritici blotch (STB), which influences wheat production across the world. In this study, genomewide association mapping was used to identify new chromosomal regions on the wheat genome conferring effective resistance towards STB. A winter wheat population of 164 North European varieties and breeding lines was genotyped with 15K single nucleotide polymorphism (SNP) wheat array. The varieties were evaluated for STB in field trials at three locations in Denmark and across 3 years. The association analysis revealed four quantitative trait loci, on chromosomes 1B, 2A, 5D and 7A, highly associated with STB resistance. By comparing varieties containing several quantitative trait loci (QTL) with varieties containing none of the found QTL, a significant difference was found in the mean disease score. This indicates that an effective resistance can be obtained by pyramiding several QTL.     

Effect of enzymes of microbial origin on in vitro digestibilities of dry matter and crude protein in soybean meal

The effects of supplementation with cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origin on digestibility of crude protein (CP) and dry matter (DM) of soybean meal in vitro were examined in the present study. Changes in viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Hemicellulase and all enzyme combinations without protease showed significant improvement of CP digestibility. Cellulase, xylanase, phytase and glucanase tended to improve CP digestibility. Dry matter digestibility was improved significantly by pectinase and all enzyme combinations. Cellulase and phytase tended to improve DM digestibility. Crude protein and DM digestibilities were the highest when all the enzymes except protease were added. Protease, cellulase, pectinase, xylanase, glucanase and hemicellulase significantly reduced viscosity, while phytase had no effect on viscosity. Viscosity was increased unexpectedly when all the enzymes were added. These results strongly suggest that a combination of carbohydrases improves the CP and DM digestibility of soybean meal while protease inhibits the actions of these enzymes. The present study also suggests that viscosity is not always a good index of digestibility. Moreover, excluding the protease from commercial crude enzyme preparations may improve digestibility.     

大气增温与干旱胁迫对灵武长枣生长与光合特性的影响

以4年生灵武长枣嫁接苗为试材,采用双因素嵌套试验设计,大气温度为正常气温和大气增温(+2.0℃)2个环境,采用红外线辐射器控制模拟增温环境,土壤自动灌溉系统控制土壤水分水平(70%~80%、50%~60%、30%~40%),研究了日间气温升高与土壤干旱胁迫交互作用对灵武长枣生长及光合特性的影响,以期为灵武长枣的栽培管理提供参考依据。结果表明:增温处理可促进枣树生长和光合作用,尤其有利于枣吊加长和叶面积的增加,净光合速率(Pn)、蒸腾速率(E)、水分利用效率(IWUE)等指标升高,但气孔导度(Gs)、胞间CO_2浓度(Ci)呈下降趋势,增温可缓解干旱胁迫对枣树生长的抑制作用。     

空间电场对蔬菜生长及营养成分的影响

以小白菜、小油菜、丝瓜和苦瓜为试材,在防虫网大棚安装空间电场条件下,研究了空间电场对蔬菜的生长和营养成分的影响。结果表明:空间电场提高了小白菜、小油菜的株高和产量,增加了小白菜、丝瓜和苦瓜的茎粗,降低了小白菜、小油菜的根冠比;4种蔬菜的叶绿素、可溶性糖含量下降;小白菜、小油菜和苦瓜的水分含量提高,但是丝瓜的水分含量降低;丝瓜和苦瓜的维生素C含量增加,而小白菜、小油菜的维生素C含量减少;空间电场还降低了小油菜、丝瓜和苦瓜的纤维素含量。总体来说,空间电场能够促进蔬菜的生长,提高蔬菜品质。     

Changes of plasma free amino acid concentrations and myofibrillar proteolysis index by starvation in non-pregnant dry cows

The effects of 5 day starvation on urinary metabolite excretion, plasma metabolites and free amino acid concentrations in four non‐pregnant dry cows were investigated. Starvation significantly reduced (P < 0.05) the bodyweight and feces weight. The plasma glucose concentration decreased (P < 0.05) during days 2–5 of starvation. Starvation significantly increased (P < 0.05) the plasma nonesterified fatty acid concentration. The plasma urea nitrogen concentration and urinary urea nitrogen excretion increased transiently (P < 0.05) at days 1 and 2 of starvation. The plasma 3‐methlhistidine concentration was significantly higher (P < 0.05) at days 2, 3 and 5 of starvation. However, the urinary 3‐methylhistidine excretion was significantly higher (P < 0.05) at days 4 and 5 of starvation, not corresponding to the change in the plasma. Starvation did not change the plasma proline, methionine, lysine and total amino acid concentrations. On the other hand, starvation reduced (P < 0.05) the plasma aspartic acid, serine, asparagine, glutamic acid, glutamine, alanine, tyrosine, tryptophan and histidine concentrations. Plasma glycine increased during starvation. Plasma threonine, isoleucine, leucine and branched‐chain amino acid increased (P < 0.05) by prolonged starvation. The results of this study indicate that prolonged starvation accelerated myofibril protein degradation in non‐pregnant dry cows and apparently consumes most glucogenic amino acids in preference to other amino acids.     

Analysis of 46-kDa protein in the perivitelline membrane of Japanese quail (Coturnix japonica)

The extracellular matrix surrounding the oocyte before ovulation is called the perivitelline membrane (PL) in avian species. The PL is constructed with two major glycoproteins, ZPC and ZP1, which are synthesized in the ovarian granulosa cells and the liver, respectively. Although the properties of the major components in the PL have been examined, knowledge about the nature of its minor constituents is lacking. In this study we focused on PL protein, which migrates at 46‐kDa in the gel of SDS‐PAGE. N‐terminal sequence analysis demonstrated that the 46‐kDa protein is the C‐terminal fragment of ZP1. Analysis of lysylendopeptidase digests or cyanogens bromide‐degraded fragments of ZP1 confirmed this postulate. Western blot analysis using antiserum against 46‐kDa protein indicated the absence of 46‐kDa protein in the serum. Moreover, small immunoreactive bands, thought to be cleaved fragments of ZP1, were detected in the PL lysate by western blot analysis using antiserum against the N‐terminal peptide of ZP1. These results indicated that the N‐terminal proteolytic processing of ZP1 might take place after the arrival of ZP1 at the ovary, and the resulting product, 46‐kDa protein, is incorporated into the PL.     

Predominant expression of growth hormone secretagogue receptor in the caudal lobe of chicken pituitary and parallel developmental increase in expression of pituitary GH and proventriculus ghrelin mRNA

To examine the involvement of ghrelin in growth hormone (GH) synthesis in the chicken pituitary, the regional distribution of GH secretagogue receptor (GHS‐R)/ghrelin receptor was investigated. Quantitative real‐time polymerase chain reaction (Q‐PCR) analysis revealed that the expression levels of GHS‐R and GH mRNA in the caudal lobe were about fourfold and sevenfold higher in the cephalic lobe of 7 day‐old chickens, respectively. Immunohistochemical analysis showed that GHS‐R immunoreactivity was more abundant in the caudal lobe than in the cephalic lobe, as was the case for GH immunoreactivity. By Q‐PCR, parallel increases were observed in the expression levels of ghrelin mRNA in the proventriculus and GH mRNA in the pituitary from embryonic day 17 to day 7 after hatching, whereas no significant change was found in the expression levels of GHS‐R mRNA in the pituitary during this period. These results suggest that proventriculus‐derived ghrelin may participate in pituitary GH synthesis by acting on its receptor during late embryonic development and the early post‐hatching period in chickens.     

Differential expression of myostatin and its receptor in the porcine anterior pituitary gland

Myostatin (MSTN), known as growth and differentiation factor 8 (GDF-8), is a member of the transforming growth factor β (TGF-β) superfamily that negatively regulates skeletal muscle mass. Myostatin binds with high affinity to the receptor serine threonine kinase activin receptor type IIB (ActRIIB). Activins that also belong to the TGF-β superfamily, stimulate follicle-stimulating hormone production in gonadotrophs and suppress growth hormone and adrenocorticotropic hormone production in somatotrophs and corticotrophs, respectively. The aim of the present paper was therefore to clarify the endocrine action of MSTN in adenohypophysis. The present study details the expression and cellular localization of MSTN and ActRIIB in porcine anterior pituitary gland. The mRNA of MSTN and ActRIIB was consistently expressed in RT-PCR. Immunohistochemistry of MSTN and specific hormones showed that MSTN localized in thyrotrophs and gonadotrophs, in which most of the MSTN immunoreactive cells were identified as thyrotrophs. The immunostaining of ActRIIB was restricted to corticotrophs. These results indicate that MSTN was mainly produced in thyrotrophs and its receptor, ActRIIB, was restrictively contained in corticotrophs. Interestingly, thyrotrophs immunoreactive for MSTN were frequently close to corticotrophs immunoreactive for ActRIIB. The present study suggests that MSTN from thyrotrophs may regulate corticotroph function as a paracrine mediator among the porcine anterior pituitary cells.     

Harpinpsta from Pseudomonas syringae pv. tabaci Is Defective and Deficient in Its Expression and HR-inducing Activity

To elucidate the role of harpins produced by Pseudomonas syringae, the corresponding hrpZ gene was isolated from P. s. pv. tabaci. The sequence information revealed that this gene carries a serious mutation with 326 bp lacking in the central region and potentially encodes only 140 N-terminal amino acids because of a frame shift. The investigation of biological properties using recombinant harpin indicated harpin_psta was incapable of inducing HR in both host and nonhost plants. Based on an immunoblot analysis to detect harpin from P. s. pathovars in hrp-inducing medium, the truncated harpin_psta was neither expressed nor secreted into the culture medium. These results suggest that harpin is not the sole determinant of the host-parasite specificity in P. s. pv. tabaci. Received 10 August 2000/ Accepted in revised form 21 December 2000     

马驽巴贝斯虫新疆伊犁株Bc48基因克隆、表达及其多克隆抗体的制备

为表达马驽巴贝斯虫新疆伊犁株Bc48基因,制备多克隆抗体,试验根据GenBank中马驽巴贝斯虫Bc48基因序列,设计合成1对特异性引物,以提取的新疆株Bc48基因组DNA为模板进行PCR扩增,将扩增产物克隆至原核表达载体pET-28a（+）中,阳性质粒转化至大肠杆菌BL21（DE3）感受态细胞中,经IPTG诱导后表达产物进行SDS-PAGE分析,切胶纯化蛋白后免疫6周龄雌性BALB/c小鼠,制备多克隆抗体;同时把该基因克隆至真核表达载体pCMV-N-flag中,将阳性质粒转化至大肠杆菌DH5α感受态细胞中,提取pCMV-N-flag-Bc48质粒转染到293T细胞中进行真核表达。结果显示,获得了大小约为15 ku的融合蛋白,与预期目的蛋白大小相一致;免疫BALB/c小鼠制备的多克隆抗体经ELISA和Western blotting检测、验证,能特异地识别相应抗原,其抗体效价可达1：128 000,说明该多克隆抗体有较高的抗体效价和特异性;真核表达质粒在293T细胞中表达Bc48蛋白。本试验可为进一步研究马驽巴贝斯虫功能基因及建立快速的检测方法奠定基础,在虫株的分类学研究及候选疫苗的研制中有重要意义。