Metabolomics reveals herbivore‐induced metabolites of resistance and susceptibility in maize leaves and roots

Plants respond to herbivory by reprogramming their metabolism. Most research in this context has focused on locally induced compounds that function as toxins or feeding deterrents. We developed an ultra‐high‐pressure liquid chromatography time‐of‐flight mass spectrometry (UHPLC‐TOF‐MS)‐based metabolomics approach to evaluate local and systemic herbivore‐induced changes in maize leaves, sap, roots and root exudates without any prior assumptions about their function. Thirty‐two differentially regulated compounds were identified from Spodoptera littoralis‐infested maize seedlings and isolated for structure assignment by microflow nuclear magnetic resonance (CapNMR). Nine compounds were quantified by a high throughput direct nano‐infusion tandem mass spectrometry/mass spectrometry (MS/MS) method. Leaf infestation led to a marked local increase of 1,3‐benzoxazin‐4‐ones, phospholipids, N‐hydroxycinnamoyltyramines, azealic acid and tryptophan. Only few changes were found in the root metabolome, but 1,3‐benzoxazin‐4‐ones increased in the vascular sap and root exudates. The role of N‐hydroxycinnamoyltyramines in plant–herbivore interactions is unknown, and we therefore tested the effect of the dominating p‐coumaroyltyramine on S. littoralis. Unexpectedly, p‐coumaroyltyramine was metabolized by the larvae and increased larval growth, possibly by providing additional nitrogen to the insect. Taken together, this study illustrates that herbivore attack leads to the induction of metabolites that can have contrasting effects on herbivore resistance in the leaves and roots.     

新疆维吾尔自治区20年问胃癌的临床特点分析

目的：分析新疆地区近20年来胃癌流行病学特征,探讨其变化规律及发展趋势。方法：回顾性分析和比较1991年、2001年、2011年经新疆维吾自治区人民医院胃镜及病理学诊断确诊为胃癌的病例的一般资料、病理学及内镜下特点,包括性别、年龄、病理类型、发病部位。结果：1991年组：胃癌检出率为2．48％,中位年龄为54岁,男女之比为3-3：1．0,发病部位以胃窦部癌为主,占39．1％;2001年组：检出率为2．39％,中位年龄为61岁,男女之比为3．0：1．0,发病部位以胃体部癌为主,占42．1％;2011年组：检出率为1．48％,中位年龄为63岁,男女之比为3．9：1．0,发病部位以贵门胃底部为主,占34．8％。三组病理学类型均以腺癌为主,检出率有逐年升高趋势,但差异无统计学意义（P〉0．05）。结论：（1）近20年来胃癌发病部位有上移现象,且胃癌检发病率有下降趋势;（2）男性胃癌患者发病率明显高于女性,且近20年来胃癌患者男女比例无明显改变;（3）近20年来胃癌发病中位年龄逐渐增高,且随着年龄的增长发病率逐渐升高,以中老年发病率最高;（4）癌患者病理类型仍以腺癌为主,且近20年来腺癌所占比例无明显变化.     

Presence of c-kit positive cells in fetal and adult bovine forestomachs

The interstitial cells of Cajal (ICC) have been reported to regulate gastrointestinal motility. We investigated the distribution and the morphological and morphometric characteristics of the immunohistochemical reaction against c-kit in the forestomachs of fetal, newborn and adult cows. The anti-c-kit reaction revealed different populations of ICC among age groups and organs. ICC were more numerous and smaller in fetuses. Larger ICC were identified in newborns, except for those in the rumen. During the earliest stages of development, ICC were abundant in the inner layer of the muscularis and were consistently associated with this layer. In all samples, ICC were found in the outer layer of the tunica muscularis. ICC were found between the two muscle layers in the omasum at all ages; however, they were identified only in the rumen of the adult. Our study demonstrated that ICC are present in the forestomach of bovines.     

Onion yield as affected by plant density,nitrogen level and loss of leaf area

Onion (Allium cepa) is an important horticulture crop because of its value as a food with a long shelf life being a relatively non-perishable product. It is very helpful to understand the growth response of the seeded onion crop to conduct appropriate field practices in attaining the highest or optimum yields. A three year field experiment was conducted using a variety of onion Valcatorce INTA, in a randomized block design with five replicates. Treatments were two plant densities and three rates of N application. The bulb growth followed a classical sigmoid curve. During the rapid growing period, the crop had the greatest leaf area (LA) with at least six leaves per plant. Increasing plant density increased yield in kg/ha, but decreased bulb size. Defoliating 40 to 60% of the LA had a significant impact on bulb production only at early growth stages. Late in the growing period, the remaining LA was apparently large enough for producing sufficient amounts of metabolites to feed new leaves, increasing their photosynthesis efficiency for the benefit of bulb production.     

Deuteron field-cycling relaxation spectroscopy and translational water diffusion in protein hydration shells.

The deuterated hydration shells of bovine serum (BSA) albumin, and purple membrane sheets have been studied by the aid of deuteron field-cycling relaxation spectroscopy. The deuteron Larmor frequency range was 10(3) to 10(8) Hz. The temperature and the water content has been varied. The data distinguish translational diffusion on the protein surface from macromolecular tumbling or exchange with free water. A theory well describing all dependences has been developed on this basis. All parameters have successfully been tested concerning consistency with other sources of information. The concept is considered as a major relaxation scheme determining, apart from cross-relaxation effects, the water proton relaxation in tissue.     

Electron transfer between cytochrome P450cin and its FMN-containing redox partner, cindoxin

Cytochrome P450 reductase, which delivers electrons from NADPH to microsomal P450s, consists of a single polypeptide that contains both FAD and FMN. The bacterial P450cin utilizes a similar electron transport system except the FAD/FMN reductase consists of two separate polypeptides where the FMN protein, cindoxin, shuttles electrons between the FAD-containing cindoxin reductase and P450cin. Here we characterize the kinetics and specificity of electron transfer between cindoxin and P450cin as well as discuss the influence of possible binding surface interactions using homology models.     

Inferring functional modules of protein families with probabilistic topic models

Background  

Genome and metagenome studies have identified thousands of protein families whose functions are poorly understood and for which techniques for functional characterization provide only partial information. For such proteins, the genome context can give further information about their functional context.     

聚酸酐控释制剂的研究进展

聚酸酐材料是一种良好的生物可降解材料,它可以作为药物载体将药物递送入人体的各个器官,如脑、骨骼、血管等,也可作为基因的载体对患者进行基因治疗。聚酸酐的合成工艺简单、成本低廉,可以满足不同的用途。它奇在人体内降解为对人体无害的二元酸而排除体内,具有良好的生物相容性。文中综述了聚酸酐的合成,聚酸酐控释制剂的制备工艺、降解、体内安全性和临床应用方面的研究进展,并提出了今后的发展方向。聚酸酐在医学方面的研究和应用必将日益广泛。