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1.
本文是基于ESI、 InCites和Web of Science数据库中,淮阴师范学院数学学科近10年(2008-2018年)的多种数据,从多个角度定量地反映淮阴师范学院数学学科在国内国际的位置及科研竞争力状况。并根据分析结果对淮阴师范学院数学学科发展提出注重论文质量,鼓励发表高水平论文;推动机构合作,扩大国际影响力;引进人才评估指标等建议。  相似文献   
2.
This study aimed at elucidating SS-bonds of HMW-gliadins (HGL) from wheat with the focus on terminators of glutenin polymerisation. HGL from wheat flour extracts non-treated or treated with the S-alkylation reagent N-ethylmaleinimide (NEMI) were compared. HGL from wheat flour Akteur were isolated, hydrolysed with thermolysin and the resulting peptides pre-separated by gel permeation chromatography and analysed by liquid chromatography/mass-spectrometry using alternating electron transfer dissociation/collision-induced dissociation. Altogether, 22 and 28 SS-peptides from samples without and with NEMI treatment, respectively, were identified. Twenty-six peptides included standard SS-bonds of α- and γ-gliadins, high-molecular-weight and low-molecular-weight glutenin subunits. Eleven SS-bonds were identified for the first time. Fifteen peptides unique to HGL contained cysteine residues from gliadins with an odd number of cysteines (ω5-, α- and γ-gliadins). Thus, gliadins with an odd number of cysteines, glutathione and cysteine had acted as terminators of glutenin polymerisation. Decisive differences between samples without and with NEMI treatment were not obvious showing that the termination of polymerisation was already completed in the flour. The two HGL samples, however, were different in the majority of ten peptides that included disulphide-linked low-molecular-weight (LMW) thiols such as glutathione and cysteine with the former being enriched in the non-treated HGL-sample.  相似文献   
3.
Maize (Zea mays L.) grain yield is strongly related to the number of harvested kernels, where kernel number can be increased by synchronously pollinating silks rather than allowing them to be progressively pollinated as they naturally appear from the husks. However, there is scarce evidence on how this practice affects kernel weight (KW) and plant grain yield (PGY), and no report exists on its effects when combined with treatments aimed to reduce apical dominance, like male sterility and detasseling. Field experiments were conducted in two growing seasons (Exp1 and Exp2) using two hybrids, cropped at contrasting stand densities (3 and 9 plants per m2) and including (i) male-fertile and male-sterile versions, (ii) tasseled and detasseled plants, and (iii) natural (NP) and synchronous pollination (SP; pollen added manually to ears bagged 5 days after initial silking) systems. Tassel growth of sterile and fertile versions was also evaluated in a separate experiment (Exp3). Detasseling increased the number of ears per plant reaching silking (P < 0.001) of NP plants, but this beneficial effect of reduced apical dominance did not improve kernel number per plant (KNP) or PGY. Similarly, the early arrest of anther growth in male-sterile plants had no clear benefit on KNP. In contrast, KNP was enhanced by synchronous pollination (range between −13% and +71%; average of +15.4% in Exp1 and +3.9% in Exp2). However, this pollination system promoted a decreased in KW (range between −30% and +4%; average of −11.8% in Exp1 and −7.8 in Exp2) such that the treatment had no effect on PGY (range between −19% and +37%; average of +1% in Exp1 and −4% in Exp2). Because plant growth rate around flowering was not different between pollination treatments, assimilate availability per kernel was reduced from ovary fertilization onwards in synchronously pollinated plants when compared to open pollinated plants. This explains the reduced KW when increasing KNP by synchronous pollination. In summary, none of the imposed treatments allowed grain yield to be increased at the plant level.  相似文献   
4.
通过分析美国基本科学指标数据库(ESI)所收录的药学、毒理学领域相关研究论文,了解目前该学科领域研究的动态发展趋势、走向。  相似文献   
5.
 枯草芽孢杆菌菌株BAB-1对番茄灰霉病菌有较强的抑制作用,为了明确其抑菌活性相关成分,通过盐酸沉淀、甲醇抽提法,从该菌株发酵上清液中分离得到了一种脂肽类化合物。经HPLC分析纯化后,发现其保留时间与表面活性素标准品基本一致。TLC层析结果表明该菌株能够产生与表面活性素标准品Rf值一致的成分。进一步通过电喷雾质谱分析,得到其[M+H]+值分别为m/z 1 009.3、1 023.4、1 037.4的成分,与已知的表面活性素3种同系物的[M+H]+值一致。最后采用PCR扩增特异性片段sfp的方法证实该菌株有产生表面活性素的同源基因。综合分析表明,枯草芽孢杆菌菌株BAB-1能够产生表面活性素,且提纯后的表面活性素具有明显的溶血和排油活性,并通过显微观察确定了其十字晶体状结构。  相似文献   
6.
    
Avenanthramides (AVNs), a group of phytochemicals which are unique to oats, provide health benefits through antioxidant activity and other bioactivities. In this study, we explored genotype-by-environment interactions and heritability for AVN concentrations in oats. Avenanthramide concentrations were quantified for 100 breeding lines and cultivars at three locations over two years. While year and environment had an influence on AVN concentrations, with the influence of year being more apparent than that of environment within a year, genotype had the largest impact on AVN concentration. All three major AVNs were found to be heritable. Two methods of calculating heritability on a line mean basis were used. The statistical method yielded heritability estimates of 0.34, 0.39, and 0.41 for AVN 2c, AVN 2p, and AVN 2f, respectively. By comparison the traditional plant breeding method yielded heritability estimates of 0.82, 0.88, and 0.89 for AVN 2c, AVN 2p, and AVN 2f, respectively, indicating that expected gains will be dependent on the scale of the breeding program, the number of target environments, and climate variability. The estimated heritabilities and the 11-fold range in AVN concentrations in the 100 genotypes studied provided evidence that variability for AVN concentration should allow breeding progress for higher AVN concentration.  相似文献   
7.
    
The viviparous Great Barrier Reef sponge Luffariella variabilis (Poléjaeff 1884) contains a range of secondary metabolites, including manoalide (1) and manoalide monoacetate (3). ESI (+) FTICR-MS accurate mass determination has, for the first time, been used to detected the presence of 3 only in an organic extract of a single L. variabilis larva showing that the parentally produced 3 is sequestered in the larva. As 3 has previously been shown to have antibacterial and quorum sensing inhibition activity, and readily converts to 1, which also exhibits similar activity, it may provide a chemical defence against predation and microbial attack.  相似文献   
8.
高效液相色谱-电喷雾质谱联用法分析罗汉果皂甙   总被引:6,自引:0,他引:6       下载免费PDF全文
 【目的】建立罗汉果皂甙的HPLC/ESI/MS2定性分析方法。【方法】采用高效液相色谱-电喷雾质谱联用法对罗汉果皂甙提取物进行分离分析。【结果】根据主要色谱峰的质谱特征,初步鉴定出罗汉果皂甙提取物中主要的皂甙成分为11-氧-罗汉果皂甙V(11-oxo-mogroside-V)、罗汉果皂甙V(mogroside-V)、罗汉果皂甙IV(mogroside-IV)、罗汉果皂甙VI(mogroside-VI)和赛门甙I(siamenoside-I)。【结论】对于罗汉果皂甙的分离及定性分析,高效液相色谱-电喷雾质谱(HPLC/ESI/MS2)联用分析法是一种方便快捷有效的方法。  相似文献   
9.
采用电喷雾多级质谱技术研究了杠柳苷A和E的质谱裂解行为。在源内诱导碰撞解离谱图中发现,从准分子离子中脱去二取代吡喃酮是杠柳苷A的主要断裂形式之一。从分子中失去不同长度的糖链以及杠柳甙元D环开裂重排失去甲醛(-30 Da)是识别该类化合物的重要依据。通过对杠柳苷A和E的质谱裂解机制和特征碎片进行研究,总结了鉴别该类化合物的方法,并对杠柳根皮中的一个未报道化合物杠柳苷X的结构进行了推测,该方法对研究杠柳中杠柳苷类化合物的分布及结构具有重要参考价值。  相似文献   
10.
Two iron chelates, one toxic (iron ‘butan’) and the other not (iron ‘octan’), were ingested by slugs (Deroceras reticulatum) at either a low (5 g kg−1 diet) or a high (100 g kg−1 diet) dose rate. In tissue sections of the digestive gland and body wall, iron was detected by energy-filtering transmission electron microscopy (EFTEM), using electron spectroscopical imaging (ESI) and electron energy-loss spectroscopy (EELS). The strongest signals for iron were obtained in secondary lysosomes of the resorptive cells in the digestive gland of slugs treated with a low dose of either compound, or with the high dose of iron ‘octan’. At the cell apices of these cells, in endocytotic vesicles and in apically located lysosomes, iron was detected only in slugs fed with either dose of iron ‘octan’. In slugs fed with the high dose of iron ‘butan’, iron could clearly be localised in the epithelial and mucus cells of the skin. The results are discussed with respect to differences in the toxicity of the two iron chelates. © 1999 Society of Chemical Industry  相似文献   
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