4,499 research outputs found
Comparative analysis of Mycobacterium tuberculosis pe and ppe genes reveals high sequence variation and an apparent absence of selective constraints.
No full textContains fulltext :
110619.pdf (Publisher’s version ) (Open Access)Mycobacterium tuberculosis complex (MTBC) genomes contain 2 large gene families termed pe and ppe. The function of pe/ppe proteins remains enigmatic but studies suggest that they are secreted or cell surface associated and are involved in bacterial virulence. Previous studies have also shown that some pe/ppe genes are polymorphic, a finding that suggests involvement in antigenic variation. Using comparative sequence analysis of 18 publicly available MTBC whole genome sequences, we have performed alignments of 33 pe (excluding pe_pgrs) and 66 ppe genes in order to detect the frequency and nature of genetic variation. This work has been supplemented by whole gene sequencing of 14 pe/ppe (including 5 pe_pgrs) genes in a cohort of 40 diverse and well defined clinical isolates covering all the main lineages of the M. tuberculosis phylogenetic tree. We show that nsSNP's in pe (excluding pgrs) and ppe genes are 3.0 and 3.3 times higher than in non-pe/ppe genes respectively and that numerous other mutation types are also present at a high frequency. It has previously been shown that non-pe/ppe M. tuberculosis genes display a remarkably low level of purifying selection. Here, we also show that compared to these genes those of the pe/ppe families show a further reduction of selection pressure that suggests neutral evolution. This is inconsistent with the positive selection pressure of "classical" antigenic variation. Finally, by analyzing such a large number of genes we were able to detect large differences in mutation type and frequency between both individual genes and gene sub-families. The high variation rates and absence of selective constraints provides valuable insights into potential pe/ppe function. Since pe/ppe proteins are highly antigenic and have been studied as potential vaccine components these results should also prove informative for aspects of M. tuberculosis vaccine design
On minimal non-PE-groups
No full textAbstractIf H is a subgroup of a finite group G, by HG denote the normal closure of H in G. G is called a PE-group if every minimal subgroup X of G satisfies NG(X) ∩ XG = X. The author proves that all PE-groups are solvable with the Fitting height at most 3 and classifies the minimal non-PE-groups
[[alternative]]The Study of Acknowledgement of Risk Management on Perception of PE Teachers in Taoyuan Junior High Schools
No full text[[abstract]]The purpose of this study was to (1) explore the acknowledgement about physical activity risk management of junior high school PE teachers in Taoyuan, (2) compare PE teachers’ perception difference about risk management with different background (3) realize the strategy of risk management plan of PE teachers in junior high school. (4) finally build effective risk management plan for all PE teachers in junior high school.
One hundred and ninety two Taoyuan PE teachers served as the subjects of this study with the questionnaire of ” PE Teacher’s Perception of The Risk Management”. This study used descriptive statistics, t-test, and one-way ANOVA to analyze data. Besides, the research also chose seven PE teachers to do semi-structured interview, trying to understand risk management strategy of PE teachers. The results were listed as below:
1.The perception of risk management of physical teachers in junior high school, based on the importance, was: theory layer, practical layer, law layer, entity and application layer.
2.Significant difference was found in gender, practical layer, law layer and entity; while other factors showed no significant difference.
3.All the interviewees didn’t take action about risk management , but all of them agreed that risk management plan of physical activity is necessary. They suggested higher authorities ask junior high school to set risk management plan for physical activity, and become an evaluated item.
In conclusion of the research, the PE teachers in junior high school think it is important to execute a better physical activity risk management. Author suggested junior high school should set risk management plan for physical activity to get “zero risk” in school.
Veterinary science : humans, animals and health
No full textThis living book is a collection of open access materials bringing scientific papers to a humanities audienc
AQA GCSE PE
No full textUnlock your full potential with this revision guide which focuses on the key content and skills you need to know. With My Revision Notes for AQA GCSE PE, which covers the Short Course, Full Course and Double Award, you can: - take control of your revision: plan and focus on the areas you need to revise with content summaries and commentary from an expert author - show you fully understand key topics by using specific examples to add depth to your knowledge of PE issues and processes - apply PE terms accurately with the help of key words and definitions on all topics - improve your skills to tackle exam questions with self-testing and exam-style questions and answers
Molecular Study of PE-PPE Complexes of Mycobacterium tuberculosis
No full textM.Phil.Mycobacterium tuberculosis (Mtb) is the etiologic agent of tuberculosis (TB), a lethal infectious disease that remains a global health threat. Like other pathogenic members of the genus, Mtb uses a set of five specialized secretion systems, ESX 1-5, to secrete a range of virulence factors across its exclusively thick and complex cell envelope. Majority of the ESX substrates belong to PE and PPE protein families and are implicated in pathogenesis in diverse ways. In Mtb, there are 100 PE and 69 PPE proteins. It is believed that many PE and PPE proteins can form specific PE/PPE pairs that give rise to their biological functions. Up to date, while several dozen PE/PPE pairs are predicted based one genome analysis, only two pairs PE8-PPE15 and PE25-PPE41 were experimentally proved. Moreover, although many PE/PPE proteins are thought to be translocated through the ESX-5 system, the mechanistic details of substrate recognition and secretion is poorly understood. This study aims to validate the molecular interaction of the predicted PE/PPE pairs by yeast two-hybrid and to characterize PPE26 and PPE31, both of which are categorized in the PPE-SVP subfamily and are tightly associated to Mtb pathogenesis.The yeast two-hybrid screening has identified 4 potential PE/PPE pairs that are co-operonic and 4 potential pairs that are located distantly in the Mtb genome. By using a combination of co-expression and pull-down assays, PPE26 and PPE31 are shown to interact with EspG5, the secretion chaperone of ESX-5. Complexes of EspG5-PPE26 and EspG5-PPE31 have also been purified. Through the construction of various truncated PPE fragments, we mapped the EspG5-binding domain and an oligomerization domain on the PPE proteins. Key residues involved in EspG5-binding were further defined by site-specific mutagenesis. By combining our knowledge of the two reported structures of PE-PPE-EspG5 complexes, homology models of EspG5-PPE26 and EspG5-PPE31 have been proposed. It is likely that the binding mode between EspG5 and PPE proteins are well conserved in the PPE-SVP sublineage. Our findings provide the first report to characterize the interaction of PPE26 and PPE31 with EspG5. Results obtained in this study will provide better understanding of the substrate recognition mode in ESX-5 secretion system in mycobacteria.結核分枝桿菌是致命感染性疾病結核病的致病因子,對全球人類的健康構成嚴重威脅。與屬内其他致病成員一致，結核分枝桿菌使用五種專門的分泌系統（ESX 1-5）通過厚而複雜的細胞被膜而分泌出一系列毒力因子。大多數ESX底物屬於PE和PPE蛋白家族，並且以不同的方式導致疾病。結核分枝桿菌含有100 個PE和69 個PPE蛋白，其中許多PE和PPE蛋白可以形成具有生物功能的PE / PPE對。通過基因組分析，迄今幾十個PE / PPE對已經被預測，而這其中只有兩對（PE8-PPE15和PE25-PPE41）被實驗證明。此外，雖然許多PE / PPE蛋白被認為是通過ESX-5系統分泌的，但是人們對於底物識別和分泌過程的細節卻了解甚少。本研究旨在通過酵母雙雜交來驗證預測的PE / PPE對並表徵PPE26和PPE31。PPE26和PPE31均屬於PPE-SVP亞家族，並與結核分枝桿菌發病機理緊密相關。本研究通過酵母雙雜交篩選鑑定了四對位於相同操作子的PE/PPE對以及四對在結核分枝桿菌基因組中相距較遠的PE / PPE對。並通過共表達和拉下實驗驗證了PPE26和PPE31與EspG5（ESX-5的分泌伴侶）間的相互作用。EspG5-PPE26複合物和EspG5-PPE31複合物也已被純化。通過構建各種截短的PPE片段，我們繪製了PPE蛋白上的EspG5結合結構域和寡聚化結構域。通過位點特異性突變進一步驗證了與EspG5結合的關鍵氨基酸。結合已經報導的兩種PE-PPE-EspG5複合物結構，我們提出EspG5-PPE26和EspG5-PPE31的相互作用模型。在PPE-SVP亞家族中，EspG5和PPE蛋白之間的結合模式很可能是保守的。我們的報道首次表徵了PPE26和PPE31與EspG5的相互作用，並為更好地了解分枝桿菌中ESX-5分泌系統中的底物識別模式提供參考。Cheng, Hiu Fu.Thesis M.Phil. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …)
Addressing Hybrid PE Mismatches: The Guidance of the Code of Conduct Group
No full textThis note addresses hybrid permanent establishment (PE) mismatches involving third countries. The author examines the McDonald’s case, an example of a hybrid PE scenario, in the context of recent guidance approved by the Code of Conduct Group
Determination of plasma lysophosphatidylethanolamines (lyso-PE) by LC-MS/MS revealed a possible relation between obesity and lyso-PE in Japanese preadolescent children : The Hokkaido study
No full textBackground: Lysophosphatidylethanolamines (lyso-PEs) are the partial hydrolysis products of phosphatidylethanolamine. Although lyso-PEs are important biomarkers in various diseases, their determination is limited by the lack of simple and efficient quantification methods. This study aims to develop an improved quantitative method for the determination of lyso-PEs and its application to an epidemiological study. Methods: Single reaction monitoring channels by collision-induced dissociation for seven lyso-PEs were established using liquid chromatography-tandem mass spectrometry. Plasma lyso-PEs were extracted with a single-phase method using an isotopically labelled internal standard for quantification. The proposed method was adopted to define lyso-PEs in plasma samples of children aged 9-12 years living in Sapporo, Japan. Results: The limit of detection and limit of quantification for each lyso-PE ranged between 0.001-0.015 and 0.002-0.031 pmol/mu L, respectively. Recoveries were found to be > 91% for all the species. The analysis results of children's plasma showed that the total lyso-PE concentrations in boys (n = 181) and girls (n = 161) were 11.53 and 11.00 pmol/mu L (median), respectively. Participants were further classified by the percentage of overweight and subgrouped as underweight (n = 12), normal range (n = 292), or overweight (n = 38). Interestingly, the reduction of lyso-PE 16:0 and increased lyso-PE 22:6 were observed in overweight children compared with normal range (Fold change: 0.909 and 1.174, respectively). Conclusions: This study successfully established a simple quantitative method to determine lyso-PE concentrations. Furthermore, our method revealed the possible relation between plasma lyso-PEs and overweight status
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