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Identification of the Staphylococcus aureus etd Pathogenicity Island Which Encodes a Novel Exfoliative Toxin, ETD, and EDIN-B

Yamaguchi, Takayuki; Nishifuji, Koji; Sasaki, Megumi; Fudaba, Yasuyuki; Aepfelbacher, Martin; Takata, Takashi; Ohara, Masaru; Komatsuzawa, Hitoshi; Amagai, Masayuki; Sugai, Motoyuki
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2002 EN
Relevância na Pesquisa
27.5%
We identified a novel pathogenicity island in Staphylococcus aureus which contains open reading frames (ORFs) similar to the exfoliative toxin (ET) gene, glutamyl endopeptidase gene, and edin-B gene in tandem and the phage resistance gene, flanked by hsdM, hsdS (restriction and modification system), and IS256. The protein encoded by the ET-like gene showed 40, 59, and 68% amino acid sequence identities with exfoliative toxin A (ETA), exfoliative toxin B (ETB), and Staphylococcus hyicus ETB (ShETB), respectively. When injected into neonatal mice, the recombinant protein derived from the ET-like gene induced exfoliation of the skin with loss of cell-to-cell adhesion in the upper part of the epidermis as observed in histological examinations, just as was found in neonatal mice injected with ETA or ETB. Western blot analysis indicated that the recombinant protein is serologically distinct from ETA and ETB. Therefore, the product encoded by this new ORF is a new ET member produced by S. aureus and is termed ETD. ETD did not induce blisters in 1-day-old chickens. In the skins of mice injected with ETD, cell surface staining of desmoglein 1 (Dsg1), a cadherin type cell-to-cell adhesion molecule in desmosomes, was abolished without affecting that of desmoglein 3 (Dsg3). Furthermore...

P150-T Utilization of ABRF sPRG Protein Standard for Developing Optimized Experimental Strategies for ETD Based Protein Identification

Biringer, R. G.; Hao, Z.; Hühmer, A. F. R.
Fonte: The Association of Biomolecular Resource Facilities Publicador: The Association of Biomolecular Resource Facilities
Tipo: Artigo de Revista Científica
Publicado em /02/2007 EN
Relevância na Pesquisa
27.43%
Conventional methodology of protein mass spectrometry using collision induced dissociation (CID) has been widely adopted for confident identification and characterization of proteins in recent years. However, CID-based protein analysis works best with relatively short peptides and many important post translational modifications are not preserved during CID-based analyses. A new fragmentation method, electron transfer dissociation (ETD), has been developed recently and introduced to linear ion trap mass spectrometer. In ETD, peptide backbone is fragmented along pathways that are analogous to those observed in ECD. ETD has been reported to not only favor multiply charged, relatively large peptides, but also preserve post translational modifications. Thus, ETD is drawing more and more attention as mass spectrometry based methods for protein identification and analysis of post-translational modifications. However, current experimental strategies, which perfectly match CID-based analysis, are not optimized for ETD. This lack of efficient experimental strategies that enhance ETD-based analysis could significantly limit the benefits which ETD can provide for the analysis of proteins.

On-Line LC-MS Approach Combining Collision-Induced Dissociation (CID), Electron-Transfer Dissociation (ETD), and CID of an Isolated Charge-Reduced Species for the Trace-Level Characterization of Proteins with Post-Translational Modifications

Wu, Shiaw-Lin; Hühmer, Andreas F.R.; Hao, Zhiqi; Karger, Barry L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.43%
We have expanded our recent on-line LC-MS platform for large peptide analysis to combine CID, electron transfer dissociation (ETD), and CID of an isolated charge-reduced (CRCID) species derived from ETD to determine sites of phosphorylation and glycosylation modifications, as well as the sequence of large peptide fragments (i.e. 2,000 to 10,000 Da) from complex proteins, such as β-casein, epidermal growth factor receptor (EGFR), and tissue plasminogen activator (t-PA) at the low fmol level. The incorporation of an additional CID activation step for a charge-reduced species, isolated from ETD fragment ions, improved ETD fragmentation when precursor ions with high m/z (∼ >1000) were automatically selected for fragmentation. Specifically, the identification of the exact phosphorylation sites was strengthened by the extensive coverage of the peptide sequence with a near continuous product ion series. The identification of N-linked glycosylation sites in EGFR and an O-linked glycosylation site in t-PA were also improved through the enhanced identification of the peptide backbone sequence of the glycosylated precursors. The new strategy is a good starting survey scan to characterize enzymatic peptide mixtures over a broad range of masses using LC-MS with data-dependent acquisition...

Mass Spectrometric Determination of Disulfide Linkages in Recombinant Therapeutic Proteins Using On-line LC-MS with Electron Transfer Dissociation (ETD)

Wu, Shiaw-Lin; Jiang, Haitao; Lu, Qiaozhen; Dai, Shujia; Hancock, William S.; Karger, Barry L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/2009 EN
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27.43%
In the biotechnology industry, the generation of incorrectly folded recombinant proteins, either from an E.coli expression system or from an over-expressed CHO cell line (disulfide scrambling), is often a great concern as such incorrectly folded forms may not be completely removed in the final product. Thus, significant efforts have been devoted to map disulfide bonds to assure drug quality. Similar to ECD, disulfide bond cleavages are preferred over peptide backbone fragmentation in ETD. Thus, an on-line LC-MS strategy combining collision induced dissociation (CID-MS2), electron transfer dissociation (ETD-MS2), and CID of an isolated product ion derived from ETD (MS3) has been used to characterize disulfide-linked peptides. Disulfide-linked peptide ions were identified by CID and ETD fragmentation, and the disulfide-dissociated (or partially dissociated) peptide ions were characterized in the subsequent MS3 step. The on-line LC-MS approach is successfully demonstrated in the characterization of disulfide linkages of recombinant human growth hormone (Nutropin), a monoclonal antibody (Herceptin) and tissue plasminogen activator (Activase). The characterization of disulfide-dissociated or partially dissociated peptide ions in the MS3 step is important to assign the disulfide linkages...

Activated-Ion ETD (AI-ETD) Improves the Ability of ETD to Identify Peptides in a Complex Mixture

Ledvina, Aaron R.; Beauchene, Nicole A.; McAlister, Graeme C.; Syka, John E. P.; Schwartz, Jae C.; Griep-Raming, Jens; Westphall, Michael S.; Coon, Joshua J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.57%
Using a modified ETD-enabled QLT mass spectrometer, we demonstrate the utility of IR activation concomitant with ETD ion-ion reactions (activated-ion ETD, AI-ETD). Analyzing 12 SCX fractions of a LysC digest of human cells (HS) using ETD, CAD, and AI-ETD, we find that AI-ETD generates 13,405 peptide spectral matches (PSMs) at a 1% false-discovery rate (1% FDR), surpassing both ETD (7,968) and CAD (10,904). We also analyze 12 SCX fractions of a tryptic HS digest and find that ETD produces 6,234 PSMs, AI-ETD 9,130 PSMs, and CAD 15,209 PSMs. Compared to ETcaD, AI-ETD generates ~80% more PSMs for tryptic whole cell lysate and ~50% more PSMs for LysC whole cell lysate.

The Generating Function of CID, ETD, and CID/ETD Pairs of Tandem Mass Spectra: Applications to Database Search*

Kim, Sangtae; Mischerikow, Nikolai; Bandeira, Nuno; Navarro, J. Daniel; Wich, Louis; Mohammed, Shabaz; Heck, Albert J. R.; Pevzner, Pavel A.
Fonte: The American Society for Biochemistry and Molecular Biology Publicador: The American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.39%
Recent emergence of new mass spectrometry techniques (e.g. electron transfer dissociation, ETD) and improved availability of additional proteases (e.g. Lys-N) for protein digestion in high-throughput experiments raised the challenge of designing new algorithms for interpreting the resulting new types of tandem mass (MS/MS) spectra. Traditional MS/MS database search algorithms such as SEQUEST and Mascot were originally designed for collision induced dissociation (CID) of tryptic peptides and are largely based on expert knowledge about fragmentation of tryptic peptides (rather than machine learning techniques) to design CID-specific scoring functions. As a result, the performance of these algorithms is suboptimal for new mass spectrometry technologies or nontryptic peptides. We recently proposed the generating function approach (MS-GF) for CID spectra of tryptic peptides. In this study, we extend MS-GF to automatically derive scoring parameters from a set of annotated MS/MS spectra of any type (e.g. CID, ETD, etc.), and present a new database search tool MS-GFDB based on MS-GF. We show that MS-GFDB outperforms Mascot for ETD spectra or peptides digested with Lys-N. For example, in the case of ETD spectra, the number of tryptic and Lys-N peptides identified by MS-GFDB increased by a factor of 2.7 and 2.6 as compared with Mascot. Moreover...

Effectiveness of CID, HCD, and ETD with FT MS/MS for degradomic-peptidomic analysis: comparison of peptide identification methods

Shen, Yufeng; Tolić, Nikola; Xie, Fang; Zhao, Rui; Purvine, Samuel O.; Schepmoes, Athena A.; Ronald, J. Moore; Anderson, Gordon A.; Smith, Richard D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.39%
We report on the effectiveness of CID, HCD, and ETD for LC-FT MS/MS analysis of peptides using a tandem linear ion trap-Orbitrap mass spectrometer. A range of software tools and analysis parameters were employed to explore the use of CID, HCD, and ETD to identify peptides isolated from human blood plasma without the use of specific “enzyme rules”. In the evaluation of an FDR-controlled SEQUEST scoring method, the use of accurate masses for fragments increased the numbers of identified peptides (by ~50%) compared to the use of conventional low accuracy fragment mass information, and CID provided the largest contribution to the identified peptide datasets compared to HCD and ETD. The FDR-controlled Mascot scoring method provided significantly fewer peptide identifications than with SEQUEST (by 1.3–2.3 fold) at the same confidence levels, and CID, HCD, and ETD provided similar contributions to identified peptides. Evaluation of de novo sequencing and the UStags method for more intense fragment ions revealed that HCD afforded more sequence consecutive residues (e.g., ≥7 amino acids) than either CID or ETD. Both the FDR-controlled SEQUEST and Mascot scoring methods provided peptide datasets that were affected by the decoy database and mass tolerances applied (e.g....

iPRG 2011: A Study on the Identification of Electron Transfer Dissociation (ETD) Mass Spectra

Askenazi, M.; Bandeira, N.; Chalkley, R.J.; Clauser, K.R.; Deutsch, E.; Lam, H.H.N.; McDonald, W.H.; Neubert, T.; Rudnick, P.A.; Martens, L.
Fonte: Association of Biomolecular Resource Facilities Publicador: Association of Biomolecular Resource Facilities
Tipo: Artigo de Revista Científica
Publicado em /10/2011 EN
Relevância na Pesquisa
27.33%
The field of mass spectrometry based proteomics has seen several key innovations over the last several years, including novel experimental methods, new instruments, and unique fragmentation strategies. The latter, in the form of electron capture dissociation (ECD) and electron transfer dissociation (ETD) have captured the imaginations of many researchers, expanding their ability to identify and analyze peptides and proteins. However, since ECD/ETD spectra differ substantial from more traditional collision induced dissociation (CID) spectra in both their prominent ion series as well as their preferred bond-breaking characteristics, the (automatic) interpretation of ECD/ETD spectra requires novel algorithm optimizations. Efficient identification of ECD/ETD spectra thus remains an active and exciting field of proteomics informatics research. In this work, the ABRF Proteome Informatics Research Group (iPRG) presents the results of a collaborative study focusing on the analysis of an LC-MS/MS dataset from a yeast lysate digested with Lys-C and enriched for highly charged peptides using strong cation exchange fractionation. The data derived from one fraction analyzed exclusively by ETD was distributed to participants for analysis in several equivalent formats...

GlycoMaster — Software for Glycopeptide Identification with Combined ETD and CID/HCD Spectra

Xin, L.; Shan, P.
Fonte: Association of Biomolecular Resource Facilities Publicador: Association of Biomolecular Resource Facilities
Tipo: Artigo de Revista Científica
Publicado em /10/2011 EN
Relevância na Pesquisa
27.39%
Objective: To automate the data analysis for the identification of glycopeptides with combined ETD and CID/HCD fragmentation. The inputs for GlycoMaster software include the raw mass spectrometry data of a Thermo Orbitrap instrument and the list of proteins in the sample. The list of proteins can be identified from the same mass spectrometry data by using a database search method. The software uses the signature ions of simple sugars in the HCD spectra to identify the HCD-ETD spectrum pairs of glycopeptides. Then the ETD spectrum in each pair is used to identify the glycopeptides sequence, the glycosylation site and glycan mass. The output of the software is an excel file that contains information about the identified glycopeptides, including glycan composition, mass error, glycan components, glycosylation site and glycopeptide sequence. A score is associated with each identification result that can be used to sort the identifications according to confidence. GlycoMaster was tested with an ETD-CID dataset containing 3561 MS and 2738 MS/MS spectra from tryptic digest of reduced and alkylated 12 standard protein mixture containing 3 glycoproteins (human serotransferrin, chicken ovalabumin and ovomucoid) from Sigma. Glycopeptides were enriched on cellulose column or by using ZIC-HILIC spin columns from EMD. Purified glycopeptides were analyzed by LTQ Orbitrap Velos ETD. PEAKSTM Studio Suite was used for spectral preprocessing and protein identification. GlycoMaster reported 161 identified HCD-ETD spectrum pairs of glycopeptides. 95 of 161 were manually validated. 68 glycopeptides were reported by GlycoMaster...

ETD Performance and Complementarity to Other Fragmentation Methods for Proteomic Analysis

Chalkley, R.
Fonte: Association of Biomolecular Resource Facilities Publicador: Association of Biomolecular Resource Facilities
Tipo: Artigo de Revista Científica
Publicado em /10/2011 EN
Relevância na Pesquisa
27.33%
Radical-driven fragmentation approaches present an alternative to the well-established collisional cleavage approaches that have dominated proteomic research up until now. With the recent availability of electron transfer dissociation (ETD) in commercial quadrupole ion trap and hybrid instruments, this technology is now accessible to many researchers. It has been described as a complementary approach to CID, and decision tree approaches have been employed where a choice between CID or ETD is made depending on the precursor m/z and charge. In this presentation I will discuss the performance of ETD for peptide identification, drawing heavily on data acquired as part of the 2011 iPRG study ‘Identification of Electron Transfer Dissocation (ETD) Mass Spectra’. Results will be compared to analyses of the same sample using CID and HCD, decision tree approaches and the difference in measuring data in the ion trap versus in the orbitrap detector. A comparison of search engine performance will be presented and methods for improving database search engine analysis of ETD data will also be discussed.

ETD in a Traveling Wave Ion Guide at Tuned Z-Spray Ion Source Conditions Allows for Site-Specific Hydrogen/Deuterium Exchange Measurements

Rand, Kasper D.; Pringle, Steven D.; Morris, Michael; Engen, John R.; Brown, Jeffery M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.43%
The recent application of electron transfer dissociation (ETD) to measure the hydrogen exchange of proteins in solution at single-residue resolution (HX-ETD) paves the way for mass spectrometry-based analyses of biomolecular structure at an unprecedented level of detail. The approach requires that activation of polypeptide ions prior to ETD is minimal so as to prevent undesirable gas-phase randomization of the deuterium label from solution (i.e., hydrogen scrambling). Here we explore the use of ETD in a traveling wave ion guide of a quadrupole-time-of-flight (Q-TOF) mass spectrometer with a “Z-spray” type ion source, to measure the deuterium content of individual residues in peptides. We systematically identify key parameters of the Z-spray ion source that contribute to collisional activation and define conditions that allow ETD experiments to be performed in the traveling wave ion guide without gas-phase hydrogen scrambling. We show that ETD and supplemental collisional activation in a subsequent traveling wave ion guide allows for improved extraction of residue-specific deuterium contents in peptides with low charge. Our results demonstrate the feasibility, and illustrate the advantages of performing HX-ETD experiments on a high-resolution Q-TOF instrument equipped with traveling wave ion guides. Determination of parameters of the Z-spray ion source that contribute to ion heating are similarly pertinent to a growing number of MS applications that also rely on an energetically gentle transfer of ions into the gas-phase...

ETD fragmentation features improve algorithm

and, Wenzhou Li; Wysocki, Vicki H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/2012 EN
Relevância na Pesquisa
27.33%
Electron transfer dissociation (ETD) is an alternative technique used in mass spectrometry-based proteomics experiments. Because it is newer, most of the protein identification algorithms for ETD are still a simple derivation of well-established collision-activated dissociation algorithms without the consideration of many unique ETD spectral features. Sridhara and coworkers recently reported removing the charge-reduced precursors and corresponding neutral loss peaks to improve ETD peptide identification with the Open Mass Spectrometry Search Algorithm (OMSSA). These peaks were also used to deduce the charge of the precursors for low resolution data. The scheme is a concrete example of implementing known ETD fragmentation features to improve a protein identification algorithm.

Systematic evaluation of alternating CID and ETD fragmentation for phosphorylated peptides

Kim, Min-Sik; Zhong, Jun; Kandasamy, Kumaran; Delanghe, Bernard; Pandey, Akhilesh
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.54%
CID has become a routine method for fragmentation of peptides in shotgun proteomics while electron transfer dissociation (ETD) has been described as a preferred method for peptides carrying labile PTMs. Though both of these fragmentation techniques have their obvious advantages, they also have their own drawbacks. By combining data from CID and ETD fragmentation, some of these disadvantages can potentially be overcome because of the complementarity of fragment ions produced. To evaluate alternating CID and ETD fragmentation, we analyzed a complex mixture of phosphopeptides on an LTQ-Orbitrap mass spectrometer. When the CID and ETD-derived spectra were searched separately, we observed 2504, 491, 2584 and 3249 phosphopeptide-spectrum matches from CID alone, ETD alone, decision tree-based CID/ETD and alternating CID and ETD, respectively. Combining CID and ETD spectra prior to database searching should, intuitively, be superior to either method alone. However, when spectra from the alternating CID and ETD method were merged prior to database searching, we observed a reduction in the number of phosphopeptide-spectrum matches. The poorer identification rates observed after merging CID and ETD spectra are a reflection of a lack of optimized search algorithms for carrying out such searches and perhaps inherent weaknesses of this approach. Thus...

Multipurpose Dissociation Cell for Enhanced ETD of Intact Protein Species

Rose, Christopher M.; Russell, Jason D.; Ledvina, Aaron R.; McAlister, Graeme C.; Westphall, Michael S.; Griep-Raming, Jens; Schwartz, Jae C.; Coon, Joshua J.; Syka, John E.P.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.43%
We describe and characterize an improved implementation of ETD on a modified hybrid linear ion trap-Orbitrap instrument. Instead of performing ETD in the mass-analyzing quadrupole linear ion trap (A-QLT), the instrument collision cell was modified to enable ETD. We partitioned the collision cell into a multi-section RF ion storage and transfer device to enable injection and simultaneous separate storage of precursor and reagent ions. Application of a secondary (axial) confinement voltage to the cell end lens electrodes enables charge-sign independent trapping for ion-ion reactions. The approximately two-fold higher quadrupole field frequency of this cell relative to that of the A-QLT, enables higher reagent ion densities and correspondingly faster ETD reactions, and, with the collision cell’s longer axial dimensions, larger populations of precursor ions may be reacted. The higher ion capacity of the collision cell permits the accumulation and reaction of multiple full loads of precursor ions from the A-QLT followed by FT Orbitrap m/z analysis of the ETD product ions. This extends the intra-scan dynamic range by increasing the maximum number of product ions in a single MS/MS event. For analyses of large peptide/small protein precursor cations...

Use of CID/ETD Mass Spectrometry to Analyze Glycopeptides

Mechref, Yehia
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/2012 EN
Relevância na Pesquisa
27.5%
Collision-induced dissociation (CID) tandem mass spectrometry (MS) does not allow the characterization of glycopeptides because of the fragmentation of their glycan structures and limited fragmentation of peptide backbones. Electron-transfer dissociation (ETD) tandem MS, on the other hand, offers an alternative approach allowing the fragmentation of only peptide backbones of glycopeptides. Characterization of glycopeptides using both CID and ETD is summarized in this unit. While CID provide information related to the composition of glycan moiety attached to a peptide backbone, ETD permits de novo sequencing of peptides, since it prompts only peptide backbone fragmentation while keeping posttranslational modifications intact. Radical anions transfer of electrons to peptide backbone which induces cleavage of the N-Cα bond is observed in ETD. The glycan moiety is retained on the peptide backbone, largely unaffected by the ETD process. Accordingly, ETD allows not only the identification of the amino acid sequence of a glycopeptide, but also the unambiguous assignment of its glycosylation site. When data acquired from both fragmentation techniques are combined, it is possible to characterize comprehensively the entire glycopeptide. This is achieved using an instrument capable of alternating between CID and ETD experiments during an LC-MS/MS analysis. This unit discusses the different fragmentation of glycopeptides observed in CID and ETD. Tables of residue masses associated with oxonium ions observed in CID are provided to help in the interpretation of CID mass spectra. The utility of both CID and ETD for better characterization of glycopeptides are demonstrated for a model glycoprotein.

Electron transfer dissociation (ETD): The mass spectrometric breakthrough essential for O-GlcNAc protein site assignments – A study of the O-GlcNAcylated protein Host Cell Factor C1

Myers, Samuel A.; Daou, Salima; Affar, El Bachir; Burlingame, AL
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/2013 EN
Relevância na Pesquisa
27.39%
The development of electron-based, unimolecular dissociation mass spectrometric methods, i.e. electron capture and electron transfer dissociation (ECD and ETD, respectively), has greatly increased the speed and reliability of labile post-translational modification (PTM) site assignment. The field of intracellular O-GlcNAc (O-linked N-acetylglucosamine) signaling has especially advanced with the advent of ETD mass spectrometry. Only within the last five years have proteomic-scale experiments utilizing ETD allowed the assignment of hundreds of O-GlcNAc sites within cells and subcellular structures. Our ability to identify and unambiguously assign the site of O-GlcNAc modifications using ETD is rapidly increasing our understanding of this regulatory glycosylation and its potential interaction with other PTMs. Here, we discuss the advantages of using ETD, complimented with collisional-activation mass spectrometry (CID/CAD), in a study of O-GlcNAc modified peptides of the extensively O-GlcNAcylated protein Host Cell Factor C1 (HCF-1). HCF-1 is a transcriptional co-regulator, forms a stable complex with O-GlcNAc transferase and is involved in control of cell cycle progression. ETD, along with higher energy collisional dissociation (HCD) mass spectrometry...

New media data to identify student training needs

Bolton, Philip, Jr
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
27.43%
The main objective is to exhibit how usage data from new media can be used to assess areas where students need more help in creating their ETDs. After attending this session, attendees will be able to use usage data from new media, in conjunction with traditional assessment data, to identify strengths and weaknesses in ETD training and resources. The burgeoning ETD program at Florida International University (FIU) has provided many opportunities to experiment with assessment strategies and new media. The usage statistics from YouTube and the ETD LibGuide revealed areas of strength and weakness in the training resources and the overall ETD training initiative. With the ability to assess these materials, they have been updated to better meet student needs. In addition to these assessment tools, there are opportunities to connect these statistics with data from a common error checklist, student feedback from ETD workshops, and final ETD submission surveys to create a full-fledged outcome based assessment program for the ETD initiative.

New media data to identify student training needs

Bolton, Philip, Jr
Fonte: SelectedWorks Publicador: SelectedWorks
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
27.43%
The main objective is to exhibit how usage data from new media can be used to assess areas where students need more help in creating their ETDs. After attending this session, attendees will be able to use usage data from new media, in conjunction with traditional assessment data, to identify strengths and weaknesses in ETD training and resources. The burgeoning ETD program at Florida International University (FIU) has provided many opportunities to experiment with assessment strategies and new media. The usage statistics from YouTube and the ETD LibGuide revealed areas of strength and weakness in the training resources and the overall ETD training initiative. With the ability to assess these materials, they have been updated to better meet student needs. In addition to these assessment tools, there are opportunities to connect these statistics with data from a common error checklist, student feedback from ETD workshops, and final ETD submission surveys to create a full-fledged outcome based assessment program for the ETD initiative.

Activated Ion ETD Performed in a Modified Collision Cell on a Hybrid QLT-Oribtrap Mass Spectrometer

Ledvina, Aaron R.; Rose, Christopher M.; McAlister, Graeme C.; Syka, John E.P.; Westphall, Michael S.; Griep-Raming, Jens; Schwartz, Jae C.; Coon, Joshua J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.52%
We describe the implementation and characterization of activated ion electron transfer dissociation (AI-ETD) on a hybrid QLT-Orbitrap mass spectrometer. AI-ETD was performed using a collision cell that was modified to enable ETD reactions, in addition to normal collisional activation. The instrument manifold was modified to enable irradiation of ions along the axis of this modified cell with IR photons from a CO2 laser. Laser power settings were optimized for both charge (z) and mass to charge (m/z) and the instrument control firmware was updated to allow for automated adjustments to the level of irradiation. This implementation of AI-ETD yielded 1.6 fold more unique identifications than ETD in an nLC-MS/MS analysis of tryptic yeast peptides. Furthermore, we investigated the application of AI-ETD on large scale analysis of phosphopeptides, where laser power aids ETD, but can produce b- and y-type ions due to the phosphoryl moiety's high IR adsorption. nLC-MS/MS analysis of phosphopeptides derived from human embryonic stem cells using AI-ETD yielded 2.4 fold more unique identifications than ETD alone, demonstrating a promising advance in ETD sequencing of PTM containing peptides.

ETD – EaD, porque não?ETD – Distance education, why not?

Souza, Regina Maria de
Fonte: ETD - Educação Temática Digital Publicador: ETD - Educação Temática Digital
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Não avaliada pelos pares Formato: application/pdf
Publicado em 07/10/2009 POR
Relevância na Pesquisa
37.25%
Apresentação - ETD – EaD, porque não? / ETD – Distance education, why not?