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111.
A major QTL for resistance to Gibberella stalk rot in maize 总被引:1,自引:0,他引:1
Qin Yang Guangming Yin Yanling Guo Dongfeng Zhang Shaojiang Chen Mingliang Xu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(4):673-687
Fusarium graminearum Schwabe, the conidial form of Gibberella zeae, is the causal fungal pathogen responsible for Gibberella stalk rot of maize. Using a BC1F1 backcross mapping population derived from a cross between ‘1145’ (donor parent, completely resistant) and ‘Y331’ (recurrent
parent, highly susceptible), two quantitative trait loci (QTLs), qRfg1 and qRfg2, conferring resistance to Gibberella stalk rot have been detected. The major QTL qRfg1 was further confirmed in the double haploid, F2, BC2F1, and BC3F1 populations. Within a qRfg1 confidence interval, single/low-copy bacterial artificial chromosome sequences, anchored expressed sequence tags, and insertion/deletion
polymorphisms, were exploited to develop 59 markers to saturate the qRfg1 region. A step by step narrowing-down strategy was adopted to pursue fine mapping of the qRfg1 locus. Recombinants within the qRfg1 region, screened from each backcross generation, were backcrossed to ‘Y331’ to produce the next backcross progenies. These
progenies were individually genotyped and evaluated for resistance to Gibberella stalk rot. Significant (or no significant) difference in resistance reactions between homozygous and heterozygous genotypes
in backcross progeny suggested presence (or absence) of qRfg1 in ‘1145’ donor fragments. The phenotypes were compared to sizes of donor fragments among recombinants to delimit the qRfg1 region. Sequential fine mapping of BC4F1 to BC6F1 generations enabled us to progressively refine the qRfg1 locus to a ~500-kb interval flanked by the markers SSR334 and SSR58. Meanwhile, resistance of qRfg1 to Gibberella stalk rot was also investigated in BC3F1 to BC6F1 generations. Once introgressed into the ‘Y331’ genome, the qRfg1 locus could steadily enhance the frequency of resistant plants by 32–43%. Hence, the qRfg1 locus was capable of improving maize resistance to Gibberella stalk rot. 相似文献
112.
Zong-wen Pang Jing-juan Liang Xiao-juan Qin Ji-rui Wang Jia-xun Feng Ri-bo Huang 《Biotechnology letters》2010,32(12):1847-1851
Kluyveromyces marxianus GX-15 was mutated multiple times by alternately treatment with UV irradiation and NTG for two cycles. Four mutant strains
with improved ethanol yield were obtained. The maximum ethanol concentration, ethanol yield coefficient and theoretical ethanol
yield of the best mutant strain, GX-UN120, was 69 g/l, 0.46 g/g and 91%, respectively, when fermenting 150 g glucose/l at
40°C. The corresponding values for GX-15 were 58 g/l, 0.39 g/g and 76%, respectively. GX-UN120 grew well in 11% (v/v) of ethanol,
while GX-15 could not grow when ethanol was greater than 8% (v/v). 相似文献
113.
目的了解铜绿假单胞菌(PA)在医院内感染的分布特点及其耐药性,指导临床合理用药,降低医院感染率。方法回顾分析2005年1月至2008年11月我院临床分离的铜绿假单胞菌152株,按WHO推荐的NC-CLS标准方法(K—B法)进行药敏试验,分析菌株的临床分布特征及体外药敏结果。结果铜绿假单胞菌在临床上主要以呼吸道感染为主。在17种临床常用抗生素中,多表现为多重耐药。美洛培南、亚胺培南及左旋氧氟沙星抗PA效果最好,耐药率分别只有14.47%、14.47和5.26%。结论多重耐药铜绿假单胞菌在临床广泛存在,应当根据临床体外药敏结果合理选择抗菌药物进行治疗,以取得良好临床效果并减少耐药菌产生;同时规范院内感染控制措施,减少耐药菌株的播散。 相似文献
114.
为研究CSFV强毒感染对猪外周血白细胞的影响,本研究用猪瘟病毒石门株(CSFV SM)感染60日龄仔猪后,分析外周血中CSFV核酸载量动态变化、白细胞亚群变化和白细胞SLAⅠ和SLAⅡDR分子的表达情况。实验结果显示:实验仔猪经CSFV感染后48小时体温升高并可以在血液中检测到CSFV核酸,核酸载量持续升高,在感染后6日(DPI)达到最大值,为2 DPI时核酸载量的104.84±0.98倍;WBC、LYM、PLT数量持续降低,WBC在1DPI和2DPI分别降至65.87%和50.00%,LYM在1~3DPI分别降至70.68%、47.88%和23.29%,PLT数量持续降低,6DPI时仅为初始值的34.59%;NK、γδT、Tc、Th、CD3+CD4+CD8+和CD3-CD4-CD8-淋巴细胞在感染后均不同程度的减少,其中NK细胞在1DPI时减少78.49%,而后变化与1DPI比较差异不显著,γδT、Tc、CD3-CD4-CD8-、CD3+CD4+CD8+在3DPI时分别降至41.74%、43.83%、15.87%和32.96%,Th细胞在感染后持续下降,在6DPI时减少至42.95%;感染后淋巴细胞中表达S... 相似文献
115.
Liu LB Hashi Y Qin YP Zhou HX Lin JM 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,845(1):61-68
An automated online gel permeation chromatography-gas chromatograph mass spectrometer (GPC-GC/MS) was developed for the rapid determination of residual pesticides in agricultural products. Pesticides were extracted from homogenized food samples with acetonitrile and decontaminated via the matrix solid-phase dispersion (MSPD) technique, using a primary secondary amine as sorbent prior to GPC-GC/MS analysis. A slightly modified preparation method and automated GPC step proved useful in minimizing matrix interference. To evaluate the performance of the system, 97 target pesticides were spiked at a concentration of 0.1mg/kg into a range of food types, including potato, cabbage, carrot, apple, orange, cucumber, and rice. A low flow rate of 0.1 mL/min in GPC resulted in a 40-fold reduction in solvent consumption compared with conventional GPC column applications. The combination of MSPD technique and GPC-GC/MS for the analysis of the 97 pesticides can be accomplished within 90 min. Most pesticides were recovered in the range of 70-120%, with relative standard deviation generally less than 10%. The results demonstrate that the method can be successfully applied with acceptable recoveries to a broad range of target pesticides within a diverse range of food types. 相似文献
116.
117.
The transport of 2-oxoisocaproate into isolated hepatocytes and liver mitochondria of rat was studied using [U-14C]2-oxoisocaproate and the silicone oil filtration procedure. 2-Oxoisocaproate uptake by hepatocytes was composed of: rapid adsorption, unmediated diffusion and carrier-mediated transport. The carrier-mediated transport was strongly inhibited by 4,4'-diisothiocyano-2,2'-stilbenedisulphonic acid and p-chloromercuribenzoate, was less sensitive to alpha-cyano-4-hydroxycinnamate and insensitive to p-chloromercuriphenylsulphonate. Other 2-oxo acids: pyruvate, 2-oxoisovalerate and 2-oxo-3-methylvalerate, were also inhibitory. The kinetic parameters of the carrier-mediated transport were Km 30.6 mM and Vmax 23.4 nmol/min per mg wet wt, at 37 degrees C. It is concluded that at its low, physiological, concentration, 2-oxoisocaproate penetrates the hepatocyte membrane mainly by unmediated diffusion. The uptake of 2-oxoisocaproate by isolated liver mitochondria was partly inhibited by alpha-cyano-4-hydroxycinnamate, the inhibitor of mitochondrial monocarboxylate carrier. The remaining uptake was linearly dependent on 2-oxoisocaproate concentration and represented unmediated diffusion. The carrier-mediated transport exhibited the following kinetic parameters: Km 0.47 mM, Vmax 1.0 nmol/min per mg protein at 6 degrees C; and Km 0.075 mM and Vmax about 8 nmol/min per mg protein at 37 degrees C. 相似文献
118.
Angiostatin production in cultivation of recombinant Pichia pastoris fed with mixed carbon sources 总被引:4,自引:0,他引:4
A recombinant strain of Pichia pastoris with a phenotype of MutS was used to produce angiostatin. Due to the low methanol consumption rate of this strain, both methanol and glycerol feedings, that produced oscillation in dissolved O2 concentration, were used during the expression phase to improve cell growth and angiostatin expression. However, enhanced cell growth led to nitrogen limitation that suppressed further production of angiostatin, but addition of ammonia allowed angiostatin concentration to reach 108 mg l–1 after an expression period of 96 h. The ratio of consumed glycerol to methanol of 1.5:1 (w/w) in the expression phase suggested that methanol played an important role in the metabolism of carbon sources. 相似文献
119.
120.
S. Promsakha Na. Sakonnakhon B. Toomsan G. Cadisch E. M. Baggs P. Vityakon V. Limpinuntana S. Jogloy A. Patanothai 《Plant and Soil》2005,272(1-2):183-199
It is generally thought that grain legume residues make a substantial net N contribution to soil fertility in crop rotation systems. However, most studies focus on effects of residues on crops immediately sown after the legume crop while in fact in many tropical countries with a prolonged dry season there is a large gap before planting the next crop with potential for nutrient losses. Thus the objectives of this study were* to improve the efficiency of groundnut (Arachis hypogaea L.) stover-N (100 kg N ha –1) recycling by evaluating the effect of dry season stover management, i.e. surface application and immediate incorporation after the legume crop or storage of residues until next cropping in the rainy season. N dynamics (litterbags, mineral N, microbial biomass N, N 2O emissions) were monitored and 15N labelled residues were applied to assess the fate of residue N in the plant–soil (0–100 cm) system during two subsequent maize crops. Recycling groundnut stover improved yield of the subsequent maize (Zea mays L.) crop compared to treatment without stover. A higher N recycling efficiency was observed when residues were incorporated (i.e. 55% total 15N recovery after second maize crop) than when surface applied (43% recovery) at the beginning of the dry season. This was despite the faster nitrogen release of incorporated residues, which led to more mineral N movement to lower soil layers. It appears that a proportion of groundnut stover N released during the dry season was effectively captured by the natural weed population (54–70 kg N ha –1) and subsequently recycled particularly in the incorporation treatment. Despite the presence of weeds major leaching losses occurred during the onset of the rainy season while N 2O emissions were relatively small. There was a good correlation between soil microbial biomass N and first crop maize yield. Incorporation of groundnut residues led to small increases in economic yield, i.e., 3120 versus 3528 kg ha –1 over two cropping cycles in the surface versus incorporation treatments respectively, with corresponding residue 15N uptakes of 4 and 8%, while 15N recovery in water stable aggregates (9–15%) was not significantly different. In contrast, when stover was removed and applied before the first crop, yield benefits were highest with cumulative maize yields of 4350 kg ha –1 and residue utilization of 12%. However, N recycling efficiency was not higher than in the early incorporation treatment due to an asynchrony of N release and maize N demand during the first crop. 相似文献