The N-acetyltransferase gene-implicated iron acquisition contributes to host specificity of Pseudomonas cichorii strain SPC9018 and its virulence

A pathogenicity island within the genome of a multi-host plant bacterium, Pseudomonas cichorii strain SPC9018, comprises the hrp genes encoding a type III secretion system and the pat gene encoding an N-acetyltransferase proposed to play a role in virulence. However, the function of the N-acetyltransferase remains poorly characterized. Interestingly, limiting the iron condition using a phytosiderophore, mugineic acid, resulted in reduced virulence of strain SPC9018 on respective host plants, including eggplant, similar to the reduced virulence observed with a pat gene-deletion mutant. Spectroscopic analyses showed that the pat deletion reduced the concentration of pyoverdine, which is the main siderophore produced by strain SPC9018, leading to a reduction in pyoverdine-mediated iron acquisition. Furthermore, the pat gene deletion mutant showed enhanced expression of the fecA, pvdL, and pvdR genes, whose expression is induced under deficient siderophore-mediated iron uptake. The pat-deletion mutant showed a hyper-swarming phenotype, and the addition of iron decreased this swarming motility. The pat deletion also reduced the adhesion ability of the bacteria, similar to the effect of iron-limited conditions. Furthermore, deletion of the pat gene enhanced expression of the hrp genes. These findings suggested that the pat gene encoding the N-acetyltransferase may be implicated in iron acquisition, contributing to host specificity of P. cichorii strain SPC9018 and its virulence.     

论野火的三属性

野火泛指发生于野外植被中的火、归纳发现有３个基本属性,自然性,灾害性和工具性,对这３个属性进行明确的定义和认识,有助于理解野火的意义,为研究和生产奠定科学系统的理论基础。自然属性一是指其自然存在、二是指其对自然界有影响,三是指其他受其他自然因子制约。灾是自然界不可控事件造成的超越一定程度界线的损失。灾害属性即经济属性。每一次火都造成巨大的经济损失,包括林资源和草资源预防和扑救开始。工具是指可以拿来     

Local pulmonary immune responses in domestic cats naturally infected with Cytauxzoon felis

Cytauxzoonosis is a hemoprotozoal disease of cats and wild felids in the South and Southeastern United States caused by Cytauxzoon felis. Although the causative agent has been recognized since the seventies, no study has examined the local immune response in affected organs, such as the lung, and compared them to the lungs of uninfected domestic cats. Previous studies have suggested that the histopathologic findings in the lungs of C. felis-infected cats are caused by the release of pro-inflammatory mediators, such as cytokines and increased production of inducible nitric oxide synthase (iNOS), by the infected macrophages. Our laboratory had previously found an upregulation of the adhesion molecule CD18, which can stimulate the release of these pro-inflammatory mediators. The objective of this study was to characterize local pulmonary immune responses in cats naturally infected with C. felis. Immunohistochemistry was performed to detect tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, iNOS, and major histocompatibility complex (MHC) II in 19 lungs from affected cats that died between 2005 and 2013. Results showed increased expression of all of these molecules when compared to lungs from uninfected, healthy cats. Furthermore, MHC II is expressed in the endothelium of C. felis naturally infected cats. These results support that there is a marked, local, pro-inflammatory immune response that can contribute to the pathogenesis of cytauxzoonosis in the lungs.     

Characterization of an intravenous lipopolysaccharide inflammation model in calves with respect to the acute-phase response

Our objective was to develop a lipopolysaccharide (LPS) inflammation model in calves to evaluate the acute-phase response with respect to the release of pro-inflammatory cytokines and acute-phase proteins, fever development and sickness behaviour. Fourteen 4-week-old male Holstein Friesian calves were included and randomly assigned to a negative control group (n = 3) and an LPS-challenged group (n = 11). The latter received an intravenous bolus injection of 0.5 μg of LPS/kg body weight. Blood collection and clinical scoring were performed at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 12, 18, 24, 28, 32, 48, 54 and 72 h post LPS administration (p.a.). In the LPS group, the following clinical signs were observed successively: tachypnoea (on average 18 min p.a.), decubitus (29 min p.a.), general depression (1.75 h p.a.), fever (5 h p.a.) and tachycardia (5 h p.a.). Subsequent to the recovery from respiratory distress, general depression was prominent, which deteriorated when fever increased. One animal did not survive LPS administration, whereas the other animals recovered on average within 6.1 h p.a. Moreover, the challenge significantly increased plasma concentrations of tumour necrosis factor-α, interleukin 6, serum amyloid A and haptoglobin, with peaking levels at 1, 3.5, 24 and 18 h p.a., respectively. The present LPS model was practical and reproducible, caused obvious clinical signs related to endotoxemia and a marked change in the studied inflammatory mediators, making it a suitable model to study the immunomodulatory properties of drugs in future research.     

国医大师孙光荣论中西医学文化的比较

中西医学分属于不同的医疗体系,认识其差异,有利于寻求两者之间的共同点和交融的契合点,从而促进医学的发展。国医大师孙光荣通过系统的对比,得出两者之间在学科属性、医疗模式、诊疗思维、发展特点、治疗特点五个方面存在较大的差异。从学科属性而言,中医学具有自然科学与社会科学的双重属性,西医学则属于单纯的自然科学;从医疗模式而言,中医学为整体医学模式,西医学为生物医学模式或生物-心理-社会医学模式;从诊疗思维而言,中医学是包容性思维,主张非定点清除致病因子,西医学则是对抗性思维,主张定点清除致病因子;从发展特点而言,中西医学呈现出起点高、发展慢与起步晚、发展快两种截然相反的状态;从治疗特点而言,中医学以"观其脉证,知犯何逆,随证治之"与"中和"为特点,西医学则强调数据支持,临床路径、介入和干预。     

Effect of enzymatic and technological treatments on solubilisation of arabinoxylans from brewer's spent grain

Brewer's spent grain (BSG), the most abundant brewing by-product, has hidden and underexploited nutritional potential. In order to valorize BSG, the effects of three commercial xylanases and a peptidase on water unextractable arabinoxylans (WUAX) were studied. Comparing all treatments, higher addition of xylanase resulted in an increase in water extractable arabinoxylans (WEAX). In the most efficient treatment, xylanase alone was able to solubilise 23.7% of WUAX, while the peptidase showed no effect. However, when added together with xylanase, peptidase increased the solubilisation of WUAX up to 1.6 folds. A positive correlation between particle size reduction and solubilisation of WUAX was also proved through milling BSG. These results suggest that access to xylan backbone increases with proteolytic activities, proving a synergistic effect of these specific enzymes. Therefore, if properly treated before being added as ingredient, BSG could add health functionalities to foodstuff while reducing the environmental impact of brewing industries.     

城市绿地土壤肥力评价的未确知属性测度分析法

基于未确知数学理论和属性数学理论,研究了土壤肥力综合评价方法,建立了城市绿地土壤肥力综合评价及分级的未确知属性测度分析法。该方法首先需要确定城市绿地土壤肥力状况的评价指标及分类标准,以及土壤肥力状况级别组数;然后构建单指标的未确知属性测度函数,以计算单指标的未确知属性测度函数值和样本的综合未确知属性测度值;最后应用置信度准则对城市绿地土壤样本进行识别,以确定土壤样本肥力状况的级别属性。基于两个城市绿地土壤样本的模糊综合评价结果,以及13个城市绿地土壤样本的全排列多边形图示指标法、物元可拓法以及改进的人工神经网络法的评价结果进行了验证,本研究方法的评价结果与模糊综合评价法、全排列多边形图示指标法、物元可拓法以及改进的人工神经网络法的一致性分别为100%、84.62%、92.31%和100%。实例评价表明,采用该方法对城市绿地土壤肥力状况进行评价是可行的,为城市绿地土壤肥力综合评价提供了新的途径和方法。     

Application of Attribute Reduct Method in Spatial Load Forecasting

Spatial load forecasting is a process distributing the total forecasted load to all partitioned area, and involving more spatial information and more factor influencing application of the future small area, which need a great deal of memory space and longer operation time. Rough set is new method of data analysis. It need not be provided with any advanced information except data set. But attribute reduct is its main algorithms. Division matrix approach on rough set used to reduce the attribute related to land - use decision in order to remove redundancy attribute and then the rules of small area land - use decision is distilled. The method obtained better effect and enhanced the total load forecasting efficiency.     

Disulphide structure of high-molecular-weight (HMW-) gliadins as affected by terminators

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.     

两株芽孢杆菌的鉴定

通过对2株芽孢杆菌的形态学、生理生化试验及16S rDNA序列同源性分析,发现B02号菌株与Ba-cillus cereus的同源性为100%,系统发育树分析与Bacillus cereus遗传关系最近,确定该菌株为Bacillus ce-reus。而B03号菌株与Bacillus cereus的同源性为98%,要确定其种还需进一步DNA杂交;该2株芽孢杆菌的芽胞数在1.0×1012个/kg体重以下安全无毒。2株芽孢杆菌的药敏性试验和拮抗性试验结果表明,参试菌对5类抗菌药物大多数都很敏感;对4种动物肠道病原菌无明显拮抗作用。通过酶系测定,参试菌都具有一定SOD酶活性。喂养实验结果表明,2株菌对雏鸡具有一定的防病治病效果。以上结论初步证明该菌株的抑病促生机理主要是生物夺氧和有益代谢产物的作用,而非优势种群、生物拮抗作用。