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Helicobacter pylori arginase mutant colonizes arginase Ⅱ knockout mice

World journal of Gastroenterology 2011年第28期17卷 3300-3309页

作者： Songhee H Kim Melanie L Langford jean-Luc Boucher Traci L Testerman david j mcgee Department of Microbiology and Immunology Louisiana State University Health Sciences Center-Shreveport University of Nebraska-Lincoln School of Biological SciencesLincoln Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques Université Paris Descartes

AIM: To investigate the role of host and bacterial arginases in the colonization of mice by Helicobacter pylori (***).METHODS: *** produces a very powerful urease that hydrolyzes urea to carbon dioxide and ammonium,which neutralizes *** is absolutely essential to *** pathogenesis;therefore,the urea substrate must be in ample supply for urease to work *** urea substrate is most likely provided by arginase activity,which hydrolyzes L-arginine to L-ornithine and *** work has demonstrated that *** arginase is surprisingly not required for colonization of wild-type ***,another in vivo source of the critical urea substrate must *** hypothesized that the urea source was provided by host arginase Ⅱ,since this enzyme is expressed in the stomach,and *** has previously been shown to induce the expression of murine gastric arginase Ⅱ.To test this hypothesis,wild-type and arginase (rocF) mutant *** strain SS1 were inoculated into arginase Ⅱ knockout ***: Surprisingly,both the wild-type and rocF mutant bacteria still colonized arginase Ⅱ knockout ***,feeding arginase Ⅱ knockout mice the host arginase inhibitor S-(2-boronoethyl)L-cysteine (BEC),while inhibiting > 50% of the host arginase Ⅰ?activity in several tissues,did not block the ability of the rocF mutant *** to *** contrast,BEC poorly inhibited *** arginase ***: The in vivo source for the essential urea utilized by *** urease is neither bacterial arginase nor host arginase Ⅱ;instead,either residual host arginase Ⅰ?or agmatinase is probably responsible.

关键词： Arginase Helicobacter pylori S-(2-boronoethyl)-L-cysteine Urease Mice

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<i>Helicobacter</i>infection decreases basal colon inflammation, but increases disease activity in experimental IBD

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Open journal of Gastroenterology 2013年第3期3卷 177-189页

作者： Christopher P. Monceaux Traci L. Testerman Moheb Boktor Paul jordan Patrick Adegboyega david j. mcgee Merilyn H. jennings Courtney P. Parker Shelly Gupta Ping Yi Vijay C. Ganta Haidy Galous Kenneth Manas j. Steven Alexander Department of Gastroenterology and Hepatology LSU Health Shreveport Shreveport USA Department of Microbiology and Immunology LSU Health Shreveport Shreveport USA Department of Molecular and Cellular Physiology LSU Health Shreveport Shreveport USA Department of Pathology LSU Health Shreveport Shreveport USA

Background: Helicobacter species are best known for their roles in the pathology of gastritis;however, several Helicobacter species also colonize the intestine, and less is known about effects of Helicobacter on the development of intestinal inflammation. To evaluate contributions of Helicobacter in inflammatory bowel disease, we investigated whether and how pre-existing intestinal colonization would affect disease severity and biomarkers of inflammation in experimental IBD. Materials and Methods: Mice were infected with H. muridarum 2 weeks prior to induction of colitis mediated by 3% dextran sulfate (DSS). Disease activity index, stool blood and consistency, colon length, myeloperoxidase, histopathology, blood and lymphatic vessels, and numbers of dilated mucosal crypts were measured in control, DSS-only, H. muridarum-infected, and H. muridarum-infected + DSS mice. Results: Prior to DSS challenge, H. muridarum-infected mice showed little distal gut injury by several indices of colon inflammation with decreased blood vessel density in the submucosa, and lower lymphatic density in the mucosa and submucosa. However, after DSS colitis, H. muridarum-infected mice exhibited significantly greater disease. Weight change, stool bleeding, diarrhea, and angiogenesis were all increased in H. muridarum-infected mice in DSS colitis compared to DSS controls. Conclusions: Our data show that Helicobacter colonization of the intestine, unlike that of the stomach, lowers basal gut inflammatory scores, but increases disease activity and inflammation in an acute colitis model. Intestinal Helicobacter infection may therefore represent a significant sub-clinical factor which predisposes the gut to inflammatory injury.

关键词： Helicobacter Colon Lymphatics Crohn’s Disease Ulcerative Colitis

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Women in visual neural regeneration research

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Neural Regeneration Research 2025年第2期20卷 489-490页

作者： Tonia S.Rex david j.Calkins Vanderbilt Eye Institute Vanderbilt University Medical CenterNashvilleTNUSA

The year 2024 marks the 60^(th)anniversary of Title IX and 25 years since the New York Times revealed bias against female faculty members at the Massachusetts Institute of *** take an opportunity here to examine the state of gender bias in a relatively new yet already prominent field,neural regeneration in the visual system,for which there is a well-defined context useful for this *** National Eye Institute(NEI)provided the first round of research funding for its Audacious Goals Initiative(AGI)on visual neural regeneration in 2013 and the last round in ***,we focus on this *** sources included PubMed,the National Science Foundation(NSF),the NEI,the Blue Ridge Institute for Medical Research and data from the major professional organization for eye and vision research,the Association for Research in Vision and Ophthalmology(ARVO).

关键词： neural visual Times

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Residual feed intake phenotype and gender affect the expression of key genes of the lipogenesis pathway in subcutaneous adipose tissue of beef cattle

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journal of Animal Science and Biotechnology 2019年第1期10卷 208-217页

作者： Clare McKenna Richard K.Porter Kate A.Keogh Sinead M.Waters Mark mcgee david A.Kenny Animal and Bioscience Research Department Teagasc Grange School of Biochemistry & Immunology Trinity College Dublin

Background: Feed accounts for up to 75% of costs in beef production systems,thus any improvement in feed efficiency(FE) will benefit the profitability of this *** feed intake(RFI) is a measure of FE that is independent of level of *** tissue(AT) is a major endocrine organ and the primary metabolic energy *** modulates a variety of processes related to FE such as lipid metabolism and glucose homeostasis and thus measures of inter-animal variation in adiposity are frequently included in the calculation of the RFI *** aim of this study was to determine the effect of phenotypic RFI status and gender on the expression of key candidate genes related to processes involved in energy metabolism within *** matter intake(DMI) and average daily gain(ADG) were measured over a period of 70 d for 52 purebred Simmental heifers(n = 24) and bulls(n = 28) with an initial BW±SD of 372±39.6 kg and 387±50.6 kg,*** feed intake was calculated and animals were ranked within gender by RFI into high(inefficient; n = 9 heifers and n = 8 bulls)and low(efficient; n = 9 heifers and n = 8 bulls) ***: Average daily gain ±SD and daily DMI ±SD for heifers and bul s were 1.2±0.4 kg and 9.1±0.5 kg,and 1.8±0.3 kg and 9.5±1 kg *** RFI heifers and bulls consumed 10% and 15% more(P < 0.05) than their low RFI counterparts,*** had a higher expression of all genes measured than bulls(P < 0.05).A gender × RFI interaction was detected for HMGCS2(P < 0.05) in which high RFI bulls tended to have lower expression of HMGCS2 than low RFI bulls(P < 0.1),whereas high RFI heifers had higher expression than low RFI heifers(P < 0.05) and high RFI bulls(P < 0.05).SLC2 A4 expression was consistently higher in subcutaneous AT of low RFI animals across ***: The findings of this study indicate that low RFI cattle exhibit upregulation of the molecular mechanisms governing glucose metabolism in adipose tiss

关键词： Adipose Cattle RFI SLC2A4

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Generalized Linear Model with Elastic Net Regularization and Convolutional Neural Network for Evaluating Aphanomyces Root Rot Severity in Lentil

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Plant Phenomics 2020年第1期2卷 378-388页

作者： Afef Marzougui Yu Ma Rebecca j.mcgee Lav R.Khot Sindhuja Sankaran Department of Biological Systems Engineering Washington State UniversityPullmanWAUSA Department of Horticulture Washington State UniversityPullmanWAUSA United States Department of Agriculture-Agricultural Research Service Grain Legume Genetics and Physiology Research UnitWashington State UniversityPullmanWAUSA

Phenomics technologies allow quantitative assessment of phenotypes across a larger number of plant genotypes compared to traditional phenotyping *** utilization of such technologies has enabled the generation of multidimensional plant traits creating big ***,to harness the power of phenomics technologies,more sophisticated data analysis methods are *** this study,Aphanomyces root rot(ARR)resistance in 547 lentil accessions and lines was evaluated using Red-Green-Blue(RGB)images of *** created a dataset of 6,460 root images that were annotated by a plant breeder based on the disease *** approaches,generalized linear model with elastic net regularization(EN)and convolutional neural network(CNN),were developed to classify disease resistance categories into three classes:resistant,partially resistant,and *** results indicated that the selected image features using EN models were able to classify three disease categories with an accuracy of up to 0:91±0:004(0:96±0:005 resistant,0:82±0:009 partially resistant,and 0:92±0:007 susceptible)compared to CNN with an accuracy of about 0:84±0:009(0:96±0:008 resistant,0:68±0:026 partially resistant,and 0:83±0:015 susceptible).The resistant class was accurately detected using both classification ***,partially resistant class was challenging to detect as the features(data)of the partially resistant class often overlapped with those of resistant and susceptible ***,the findings provided insights on the use of phenomics techniques and machine learning approaches to provide quantitative measures of ARR resistance in lentil.

关键词： classify Elastic roots

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Natural products and drug discovery

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National Science Review 2022年第11期9卷 37-57页

作者： david j.Newman NIH Special Volunteer

This review covers the recent history of a series of very important natural products and their derivatives that are currently in use or under evaluation in the areas of anti-infectives, important cancer treatments that include antibody drug conjugates, followed by a discussion of type 2 diabetes(T2DM) drugs and angiotensin converting enzyme inhibitors. The current structures of the agents are shown, though in the case of some peptides used in T2DM drugs the standard single leTher abbreviation for an amino acid is used.

关键词： artemisinin glycopeptides anthracyclines dolastatin diabetes 2 ACE inhibitors

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Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： david j.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Positron emission particle tracking——Application and labelling techniques

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Particuology 2008年第1期6卷 16-23页

作者： david j. Parker School of Physics and Astronomy the University of Birmingham Edgbaston Birmingham B15 2TT UK

The positron emission particle tracking （PEPT） technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles （up to three particles） by detecting the pairs of backto-back 511 keV γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

关键词： PEPT Tracer Algorithm Tracking

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Vlendelian randomization： loosening the Gordian knot of testosterone and male ageing

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Asian journal of Andrology 2013年第5期15卷 579-581页

作者： david j Handelsman ANZAC Research Institute University of SydneySydney NSW 2139 Australia

It is unknown whether the reduced blood testosterone among unselected older men （＂andropause＂） compared to healthy younger men is due to ageing per se or as a non-specific adaptive reaction to chronic diseases acc... 详细信息

关键词： Mendelian randomization loosening male ageing

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Pico-washing:simultaneous liquid addition and removal for continuous-flow washing of microdroplets

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Microsystems & Nanoengineering 2022年第2期8卷 249-261页

作者： Michael j.Siedlik david Issadore Department of Bioengineering University of PennsylvaniaPhiladelphiaPA 19104United States

Droplet microfluidics is based on a toolbox of several established unit operations,including droplet generation,incubation,mixing,pico-injection,and *** the last two decades,the development of droplet microfluidic systems,which incorporate these multiple unit operations into a workflow,has demonstrated unique capabilities in fields ranging from single-cell transcriptomic analyses to materials *** unit operation that is sorely underdeveloped in droplet microfluidics is washing,exchange of the fluid in a droplet with a different ***,we demonstrate what we name the"pico-washer,"a unit operation capable of simultaneously adding fluid to and removing fluid from droplets in flow while requiring only a small footprint on a microfluidic *** describe the fabrication strategy,device architecture,and process parameters required for stable operation of this technology,which is capable of operating with kHz droplet ***,we provide an image processing workflow to characterize the washing process with microsecond and micrometer ***,we demonstrate the potential for integrated droplet workflows by arranging two of these unit operations in series with a droplet generator,describe a design rule for stable operation of the pico-washer when integrated into a system,and validate this design rule *** anticipate that this technology will contribute to continued development of the droplet microfluidics toolbox and the realization of novel droplet-based,multistep biological and chemical assays.

关键词： operations simultaneous removing

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