共查询到20条相似文献,搜索用时 15 毫秒
1.
Croucher NJ Harris SR Fraser C Quail MA Burton J van der Linden M McGee L von Gottberg A Song JH Ko KS Pichon B Baker S Parry CM Lambertsen LM Shahinas D Pillai DR Mitchell TJ Dougan G Tomasz A Klugman KP Parkhill J Hanage WP Bentley SD 《Science (New York, N.Y.)》2011,331(6016):430-434
Epidemiological studies of the naturally transformable bacterial pathogen Streptococcus pneumoniae have previously been confounded by high rates of recombination. Sequencing 240 isolates of the PMEN1 (Spain(23F)-1) multidrug-resistant lineage enabled base substitutions to be distinguished from polymorphisms arising through horizontal sequence transfer. More than 700 recombinations were detected, with genes encoding major antigens frequently affected. Among these were 10 capsule-switching events, one of which accompanied a population shift as vaccine-escape serotype 19A isolates emerged in the USA after the introduction of the conjugate polysaccharide vaccine. The evolution of resistance to fluoroquinolones, rifampicin, and macrolides was observed to occur on multiple occasions. This study details how genomic plasticity within lineages of recombinogenic bacteria can permit adaptation to clinical interventions over remarkably short time scales. 相似文献
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EGFR mutations in lung cancer: correlation with clinical response to gefitinib therapy 总被引:1,自引:0,他引:1
Paez JG Jänne PA Lee JC Tracy S Greulich H Gabriel S Herman P Kaye FJ Lindeman N Boggon TJ Naoki K Sasaki H Fujii Y Eck MJ Sellers WR Johnson BE Meyerson M 《Science (New York, N.Y.)》2004,304(5676):1497-1500
Receptor tyrosine kinase genes were sequenced in non-small cell lung cancer (NSCLC) and matched normal tissue. Somatic mutations of the epidermal growth factor receptor gene EGFR were found in 15of 58 unselected tumors from Japan and 1 of 61 from the United States. Treatment with the EGFR kinase inhibitor gefitinib (Iressa) causes tumor regression in some patients with NSCLC, more frequently in Japan. EGFR mutations were found in additional lung cancer samples from U.S. patients who responded to gefitinib therapy and in a lung adenocarcinoma cell line that was hypersensitive to growth inhibition by gefitinib, but not in gefitinib-insensitive tumors or cell lines. These results suggest that EGFR mutations may predict sensitivity to gefitinib. 相似文献
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目的:分析急性感染致全身炎症反应综合征(SIRS)的临床特征,提高对SIRS的认识水平。方法:按美国胸科医师学会和危重医学学会(ACCP/SCCM)的SIRS诊断标准分析感染性SIRS367例的临床资料。结果:感染性SIRS367例中符合2项标准者144例,符合3项标准者135例,3项以上者93例,并发多器官功能障碍综合征(MODS)93例,死亡63例;随着符合SIRS标准的项数增加.并发功能障碍的脏器增多,病死率升高。88.2%MODS患者表现为双相迟发型发病过程。革兰阴性杆菌引起的SIRS的病死率高于革兰阳性球菌引起的SIRS;糖发质激素治疗不能降低SIRS的病死率,感染菌对泰能有较高的敏感率。结论:临床医生必须重视SIRS、MODS的诊治及预防。 相似文献
4.
Midbrain single units correlating with pupil response to light 总被引:1,自引:0,他引:1
J D Smith L Y Ichinose G A Masek T Watanabe L Stark 《Science (New York, N.Y.)》1968,162(859):1302-1303
The consensual response of the pupil in the cat was driven by means of a light flux impinging on the contralateral retina. Spike trains recorded extracellularly from single units in the midbrain show correlation with the concurrently recorded pupil area. The temporal dynamics found confirm two earlier studies of sinigle-unit responses and quantitative nerve stimulation. Both of these indicate that most of the 200-millisecond transport delay resides in the neuromuscular apparatus. Neurons whose activity correlated either with constriction with dilatation phases of Change in the pupil area were observed. 相似文献
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Rudinsky JA 《Science (New York, N.Y.)》1966,152(3719):218-219
Douglas-fir oleoresin and the terpene hydrocarbons (alpha-pinene, beta-pinene, litnonene, camphene, geraniol, and alpha-terpineol) attracted various bark and timber beetles associated with Douiglas-fir forests during their flight. In responding to these volatile terpenes the bettles are directed to favorable breeding material. 相似文献
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Previous research has indicated that intracerebral injection of potassium chloride, and the resultant electrical silence of the brain, lead to the attenuation of a previously conditioned emotional response; this response may reflect conditioned fear. The data reported here indicate that the normal mobilization of corticosteroids, perhaps a second index of emotionality, is also attenuated by such injections. 相似文献
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《农业科学学报》2019,18(7):1451-1459
2′-5′-Oligoadenylate synthetase like protein(OASL) plays a key role in response to viral infections through selectively activating the OAS/RNase L or OASL/RIG-I signaling pathway. Although classic pathway of OASL is well-known, its regulated genes or co-actors are largely unknown. To study the possible molecular mechanism of duck OASL(dOASL), we performed RNA-sequencing(RNA-seq) and immunoprecipitation and mass spectrometry(IP-MS) at the level of mRNA and protein, respectively. For RNA-seq, we used DF1 cell lines(DF1 dO ASL+/+, DF1 cO ASL–/–, and DF1) with or without the CK/0513 H5 N1 virus(A/chicken/huabei/0513/2007) infection. 1 737 differentially expressed genes(DEGs) were identified as candidate target genes regulated by dOASL. Gene Ontology(GO), Kyoto Encyclopedia of Genes and Genomes(KEGG) analysis and Weighted Correlation Network Analysis(WGCNA) were performed. We identified one important yellow co-expression module correlated with antiviral immune response. In this module, Ankyrin repeat and FYVE domain containing 1(ANKFY1), harboring a BTB domain similar to the methyl CpG-binding protein 1(MBD1) which bound to OASL in human, was regulated by dOASL. At protein level, 133 host proteins were detected. Interestingly, ANKFY1 was one of them binding to dOASL protein. Further phylogenomic and chromosomal syntenic analysis demonstrated MBD1 was absent in birds, while mammals retained. It is suggested that OASL-ANKFY1 interaction might act as a compensatory mechanism to regulate gene expression in birds. Our findings will provide a useful resource for the molecular mechanism research of dOASL. 相似文献
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为了探讨含泥岩夹层盐穴储气库在可燃气体爆炸作用下的稳定性,利用有限差分软件FLAC^3D,建立盐穴储气库的数值模型,分析爆炸载荷作用下含泥岩夹层盐穴储气库的动态响应,包括储气库围岩的应力状态变化、地震动幅值及稳定性等。结果表明:在可燃气体爆炸载荷作用下,泥岩夹层与盐岩中应力变化基本一致,不存在明显的薄弱部位;人工拟合爆炸波对洞室围岩的冲击作用比三角形爆炸波作用强;可燃气体爆炸作用对洞室围岩破坏的影响有限,随洞室深度的增大迅速衰减;深埋盐穴储气库比浅埋洞室抵抗爆炸作用的能力更强,有利于储气库洞室的稳定性。 相似文献
11.
Gladfelter WB 《Science (New York, N.Y.)》1975,189(4202):570-571
Under increasing intensity of light, the normal tentacles of Lebrunea contract whereas the pseudotentacles expand; in decreasing light the reverse is true. This behavior may be correlated with greater numbers of zooxanthellae in the pseudotentacles. Simultaneous but opposite response of parts suggests adaptations toward photosynthesis by day and predation by night. 相似文献
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模糊数学评价与响应面结合优化老北京豆汁儿的发酵工艺 总被引:1,自引:0,他引:1
以感官评价为指标,通过响应面试验对豆汁儿的发酵工艺参数进行筛选,为克服感官评分法主观性和片面性对结果的影响,利用模糊数学进行进一步验证分析。通过豆汁儿发酵对其菌种进行16S rDNA鉴定,结果表明豆汁儿中存在粪肠球菌分离株(Enterococcus Faecium isolate);豆汁儿发酵最佳工艺参数为:发酵时间24 h、发酵温度37℃和液料比为8:1 g·g~(-1)。 相似文献
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Probability of profitable yield response to nitrification inhibitor used with liquid swine manure on corn 总被引:1,自引:0,他引:1
Nitrification inhibitors (NI) can be used with liquid swine manure (LSM) to decrease potential NO3 losses, but knowledge specifying when and where NI can increase corn (Zea mays L.) yields is limited. Eleven on-farm evaluation trials (OET) were conducted in 2009 and 15 in 2010 to identify site-specific factors for using Instinct (an encapsulated form of nitrapyrin) with LSM in Iowa. Farmers injected LSM in the fall in at least three field-long strips with and without NI. Yield responses (YR) to NI were calculated by dividing yield monitor data into 50-m cells within each field. Hierarchical models were used to estimate predictive probabilities of profitable YR for two categories of monthly average rainfall and soil drainage. On average, NI produced no YR in relatively normal 2009 and a 0.15 Mg ha?1 YR in extremely wet 2010. The NI did not change late-season corn N status but half of corn stalk nitrate test (CSNT) samples were N deficient in 2009 and about 65 % in 2010. Fields receiving >90 cm March through August rainfall in 2010 were predicted 65 % more likely to have economic YR (>0.13 Mg ha?1) than fields receiving <90 cm rainfall. Within-field variability in YR was about four times greater than among-field variability, but within field-level factors had no significant effects on YR. The NI effects may not have lasted long enough to increase yields across all OET and predictive probabilities suggest that NI may produce profitable YR only when spring and summer rainfall exceed the long-term averages by more than 40 %. 相似文献
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为明确番茄接种根结线虫后基因种类和表达量在转录水平的变化规律,利用RNA-seq对未接种及接种南方根结线虫2龄幼虫6、12、24和48 h的番茄进行转录组测序,探究番茄响应南方根结线虫侵染相关的关键转录因子,并采用qRT-PCR方法对测序结果进行验证。结果显示,接种南方根结线虫后6、12、24和48 h分别有350、390、580、1 154个基因差异表达,其中差异表达转录因子分别为11、11、19、50个。这些转录因子属于15个家族,其中数量最多的为MYB家族和bHLH家族(均为20个),其次是ERF家族19个、WRKY家族15个、bZIP家族9个。南方根结线虫侵染过程差异表达最明显的主要为ERF、WRKY、MYB和bHLH家族转录因子,其中Solyc03g005520、Solyc02g094270和Solyc09g066350显著上调,接种后48 h log2FC分别为 9.16、6.49和6.33;Solyc02g079280、Solyc12g100140 和Solyc04g072460显著下调,接种后48 h log2FC分别为-2.60、-1.72和-1.70。qRT-PCR验证结果显示,6个随机选取基因的表达趋势与测序结果基本一致。以上结果表明,ERF、WRKY、MYB和bHLH家族转录因子可能参与番茄与南方根结线虫互作,在番茄响应南方根结线虫侵染反应中发挥着重要的调控作用。 相似文献
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【目的】探明自然低温对不同磷素供给的闽楠Phoebe bournei苗木叶片生理特性的影响。【方法】设置8个磷素水平的单因素盆栽试验,施肥结束后,将苗木置于自然低温环境处理,测定其叶片的光合生理特性及其他生理指标,采用主成分分析法评价苗木抗寒性。【结果】在自然低温环境时,随磷素水平的升高,正负相关指标均表现出了明显的升降趋势。30 mg·株-1磷素供应量的闽楠苗木叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、光合水分利用效率(WUE)、脯氨酸含量和超氧化物歧化酶(SOD)活性均最高,其值分别为3.09μmol·m-2·s-1、0.023 mol·m-2·s-1、350.18μmol·mol-1、0.32 mmol·m-2·s-1、9.69、41.58μmol·g-1和332.03 U·g-1,丙二醛含量和气孔限制值(Ls)为第2低,其值分别为3.77μg·g-1和0.34。主成分综合分析结果显示,30 mg·株-1磷素供应量苗木得分最高。【结论】30 mg·株-1磷素供给最有利于闽楠苗木抗低温胁迫能力的提高。 相似文献
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对氮效率表现差异显著的3个玉米自交系幼苗采用不同光强和氮浓度处理,比较根冠比、生物产量、硝酸还原酶和谷氨酰胺合成酶的响应差异.结果表明:不同氮效率自交系对不同氮浓度与光照强度处理的响应存在显著差异;氮低效材料在低光低氮条件下的生物产量表现比氮高效材料好,在高光高氮条件下时生物产量表现比氮高效差;氮高效材料随着氮浓度增加比氮低效材料更能保持根的发达性,发达的根系是氮高效的保证.不同氮效率自交系生物产量、硝酸还原酶和谷氨酰胺合成酶光氮最佳耦合点的值不同,氮低效自交系出现光氮最佳耦合点时所需要的氮浓度(或光强)要比氮高效自交系低.因此,玉米基因型氮效率的发挥不但需要适宜的供氮水平,还需要合适的光照强度. 相似文献
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为探索不同根际pH下,景天三七对重金属铅的忍耐指数和植株各个部位铅含量的积累规律,并找到提高植株对Pb2+耐受性的pH值。在不同根际pH(5、6、7、8)条件下,采用水培试验,研究景天三七在不同铅浓度(0、20、60、100、140 mg·L-1)下对铅积累与铅胁迫的生理响应。结果表明:1)在相同pH条件下,随着铅浓度的增加,景天三七根长、株高和干质量均逐渐减小,生长受到抑制,忍耐指数逐渐下降;叶绿素含量呈现先增加后降低的趋势,谷胱甘肽(GSH)含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性逐渐降低,MDA含量逐渐增加;根、茎、叶中铅含量随着铅浓度的增加而逐渐增加,且铅积累量表现为根>茎>叶。2)在相同Pb2+浓度条件下,随着pH的增加,根长、株高和干质量表现为先增加后降低的趋势;当pH=6时,植株生长较好,忍耐指数最高;忍耐指数、叶绿素含量、GSH含量和SOD、POD、CAT活性均表现出先增加后降低的趋势,且pH=6时达最大值;MDA含量变化则相反,pH=6时达最小值;根、茎、叶的铅含量逐渐降低。综上,景天三七生长受pH及Pb2+浓度的影响,pH影响Pb2+的吸收,根际pH为6时能提高植物对铅的耐受性,且Pb2+为20 mg·L-1时,对铅的耐受性最强。 相似文献
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Huntington's disease: two families with differing clinical features show linkage to the G8 probe 总被引:8,自引:0,他引:8
S E Folstein J A Phillips D A Meyers G A Chase M H Abbott M L Franz P G Waber H H Kazazian P M Conneally W Hobbs 《Science (New York, N.Y.)》1985,229(4715):776-779
To test the hypothesis that interfamily variability in Huntington's Disease (HD) is due to mutation at different loci, linkage analysis was undertaken in two large HD kindreds that differed in ethnicity, age-at-onset, and neurologic and psychiatric features. Both families showed linkage of the HD locus to the G8 probe. Several recombinants were documented in each family, and the best estimate of the recombination fraction for the two families was 6 percent with a 95 percent confidence interval of 0 to 12 percent. Although the data support the existence of a single HD locus, use of the G8 probe for presymptomatic testing in these kindreds would have resulted in a 12 percent error rate in genotype assignment at the HD locus. 相似文献
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Qin-lei RONG Ruo-nan LI Shao-wen HUANG Ji-wei TANG Yan-cai ZHANG Li-ying WANG 《农业科学学报》2018,17(6):1432-1444
Greenhouse vegetable production has been characterized by high agricultural inputs, high temperatures, and high cropping indexes. As an intensive form of agriculture, nutrient cycling induced by microbial activities in the greenhouses is relatively different from open fields in the same region. However, the responses of soil microbial biomass carbon (MBC) and nitrogen (MBN), enzyme activities, microbial community composition, and yield to organic amendment are not well understood. Therefore, a 5-year greenhouse tomato (Solanum lycopersicum Mill.)-cucumber (Cucumis sativus L.) rotation experiment was conducted. The field experiment comprised 5 treatments: 4/4CN (CN, nitrogen in chemical fertilizer), 3/4CN+1/4MN (MN, nitrogen in pig manure), 2/4CN+2/4MN, 2/4CN+1/4 MN+1/4 SN (SN, nitrogen in corn straw) and 2/4CN+2/4SN. The amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) were equal in the five treatments. Starting with the fourth growing season, the optimal yield was obtained from soil treated with straw. MBC, MBN, phospholipid fatty acid (PLFA) profiles, and enzyme activities were significantly changed by 5 years of substitution with organic amendments. Redundancy analysis showed that MBC accounts for 89.5 and 52.3% of the total enzyme activity and total community variability, respectively. The activities of phosphomonoesterase, N-acetyl-glucosaminidase, and urease, and the relative abundances of fungi, actinomycetes, and Gram-negative bacteria were significantly and positively related to vegetable yields. Considering the effects of organic amendments on soil microbial characteristics and vegetable yield, 2/4CN+1/4MN+1/4SN can improve soil quality and maintain sustainable high yield in greenhouse vegetable production. 相似文献
20.
用水蒸气蒸馏法提取了8种不同小菊品种的花冠精油,并利用嗅觉仪和触角电位(EAG)仪比较分析了西方蜜蜂对不同小菊品种花冠精油的嗅觉和触角电位反应。结果表明:西方蜜蜂对不同品种小菊花冠精油挥发物的嗅觉反应不同。其中,西方蜜蜂对0.1μL·mL-1的‘金陵春梦’和‘金陵晚霞’挥发油表现出明显的正趋性,选择系数分别为0.72和0.63。西方蜜蜂对不同品种(或材料)小菊花冠精油的EAG反应亦有差异,其中对‘04-1-29’、‘金陵双秀’小菊的EAG反应值显著大于其他供试小菊(P<0.05),而对‘金陵锦袍’和‘04-8-8’小菊的EAG反应值小于其他供试小菊。 相似文献