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https://www.readbyqxmd.com/read/28636332/new-insights-into-the-wavelength-dependence-of-maldi-mass-spectrometry
#1
Marcel Niehaus, Andreas Schnapp, Annika Koch, Jens Soltwisch, Klaus Dreisewerd
The interplay between the wavelength of the laser and the absorption profile of the matrix constitutes a crucial factor in matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). Numerous studies have shown that typically best analytical results are obtained if the laser wavelength matches the UV absorption band of the matrix in the solid state well. However, many powerful matrices exhibit peak absorptions which differ notably from the standard MALDI laser wavelengths of 337, 349, and 355 nm, respectively...
June 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28636327/maldi-ms-guided-liquid-microjunction-extraction-for-ce-esi-ms-analysis-of-single-pancreatic-islet-cells
#2
Troy J Comi, Monika A Makurath, Marina C Philip, Stanislav S Rubakhin, Jonathan V Sweedler
The ability to characterize chemical heterogeneity in biological structures is essential to understanding cellular level function in both healthy and diseased states, but these variations remain difficult to assess using a single analytical technique. While mass spectrometry (MS) provides sufficient sensitivity to measure many analytes from volume-limited samples, each type of mass spectrometric analysis uncovers only a portion of the complete chemical profile of a single cell. Matrix-assisted laser desorp-tion/ionization (MALDI) MS and capillary electrophoresis electrospray ionization (CE-ESI)-MS are complementary analytical platforms frequently utilized for single cell analysis...
June 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28631328/phenotypic-characterisation-of-coagulase-negative-staphylococci-isolated-from-blood-cultures-in-newborn-infants-with-a-special-focus-on-staphylococcus-capitis
#3
Gustaf Ehlersson, Bengt Hellmark, Olov Svartström, Bianca Stenmark, Bo Söderquist
AIM: This Swedish study determined which species of coagulase-negative staphylococci (CoNS) were found in neonatal blood cultures and whether they included Staphylococcus capitis clones with decreased susceptibility to vancomycin. METHODS: CoNS isolates (n=332) from neonatal blood cultures collected at Örebro University Hospital during 1987-2014 were identified to species level with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)...
June 20, 2017: Acta Paediatrica
https://www.readbyqxmd.com/read/28630686/fecal-carriage-of-extended-spectrum-%C3%AE-lactamase-and-carbapenemase-producing-enterobacteriaceae-in-egyptian-patients-with-community-onset-gastrointestinal-complaints-a-hospital-based-cross-sectional-study
#4
H M Abdallah, N Alnaiemi, E A Reuland, B B Wintermans, A Koek, A M Abdelwahab, A Samy, K W Abdelsalam, C M J E Vandenbroucke-Grauls
OBJECTIVES: The aim of this study was to determine the prevalence of extended-spectrum β-lactamase (ESBL) and carbapenemase production among Enterobacteriaceae isolated from ambulatory patients with gastrointestinal complaints admitted to El-Ahrar General Hospital, Zagazig, Egypt in the period between January 2013 and May 2013. METHODS: One hundred and thirteen Enterobacteriaceae isolates were recovered from 100 consecutive Egyptian patients with community-onset gastrointestinal complaints...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/28630187/cumulative-effect-of-an-antimicrobial-stewardship-and-rapid-diagnostic-testing-bundle-on-early-streamlining-of-antimicrobial-therapy-in-gram-negative-bloodstream-infections
#5
P B Bookstaver, E B Nimmich, T J Smith, J A Justo, J Kohn, K L Hammer, C Troficanto, H A Albrecht, M N Al-Hasan
OBJECTIVES: The use of rapid diagnostic tests (RDT) enhances antimicrobial stewardship programs (ASP) interventions in optimization of antimicrobial therapy. This quasi-experimental cohort study evaluates the combined impact of an ASP/RDT bundle on appropriateness of empirical antimicrobial therapy (EAT) and time to de-escalation of broad-spectrum agents (BSAA) in gram-negative bloodstream infections (GNBSI). METHODS: ASP/RDT bundle consisted of a system-wide GNBSI treatment guidelines, prospective stewardship monitoring, and sequential introduction of two RDTs, Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) and FilmArray® Blood Culture Identification (BCID) panel...
June 19, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28629229/colistin-resistance-associated-with-outer-membrane-protein-change-in%C3%A2-klebsiella-pneumoniae-and-enterobacter-asburiae
#6
Béla Kádár, Béla Kocsis, Ákos Tóth, Katalin Kristóf, Péter Felső, Béla Kocsis, Katalin Böddi, Dóra Szabó
In this study, outer membrane proteins (OMPs) of colistin-resistant Klebsiella pneumoniae and Enterobacter asburiae were analyzed. One colistin-susceptible and three colistin-resistant K. pneumoniae sequence type 258 strains as well as one colistin-susceptible E. asburiae and its colistin-heteroresistant counterpart strain were involved in the study. OMP analysis of each strain was performed by microchip method. Matrix-assisted laser desorption ionization time of flight/mass spectrometry (MALDI-TOF/MS) investigation was carried out after separation of OMPs by two-dimensional gel electrophoresis and in-gel digestion...
June 20, 2017: Acta Microbiologica et Immunologica Hungarica
https://www.readbyqxmd.com/read/28628752/high-prevalence-of-resistance-to-fluoroquinolones-and-tetracycline-campylobacter-spp-isolated-from-poultry-in-poland
#7
Anna Woźniak-Biel, Gabriela Bugla-Płoskońska, Alicja Kielsznia, Kamila Korzekwa, Anna Tobiasz, Agnieszka Korzeniowska-Kowal, Alina Wieliczko
Campylobacter spp. is a major cause of foodborne diseases in humans, particularly when transmitted by the handling or consumption of undercooked poultry meat. Most Campylobacter infections are self-limiting, but antimicrobial treatment (e.g., fluoroquinolones and macrolides) is necessary in severe or prolonged cases. The indiscriminate use of these drugs, both in clinical medicine and animal production, has a major impact on public health. The aim of the present study was to identify Campylobacter strains, isolated from turkey and broilers, using both PCR and the matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) methods to reveal the accuracy of identification, as well to evaluate the antimicrobial and genetic resistance of the investigated strains...
June 19, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28624795/tissue-and-serum-lipidome-shows-altered-lipid-composition-with-diagnostic-potential-in-mycosis-fungoides
#8
Chenchen Xu, Dan Zhou, Yixin Luo, Shuai Guo, Tao Wang, Jie Liu, Yuehua Liu, Zhili Li
Mycosis fungoides (MF) is the most common type of cutaneous T cell lymphoma. In this study, we used matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS) to perform lipidomic profiling of 5 MF tissue samples and 44 serum samples (22 from MF patients and 22 from control subjects). Multivariate statistical analysis of the mass spectral data showed that MF tissues had altered levels of seven lipids and MF sera had altered levels of twelve. Among these, six phosphotidylcholines, PC (34:2), PC (34:1), PC (36:3), PC (36:2), PC (32:0), and PC (38:4) and one sphingomyelin, SM (16:0) were altered in both MF tissues and sera...
May 26, 2017: Oncotarget
https://www.readbyqxmd.com/read/28623565/the-novel-oleaginous-bacterium-sphingomonas-sp-egy1-dsm-29616-a-value-added-platform-for-renewable-biodiesel
#9
Nehad N Amer, Yasser Elbahloul, Amira M Embaby, Ahmed Hussein
Oleaginous microorganisms are regarded as efficient, renewable cell factories for lipid biosynthesis, a biodiesel precursor, to overwhelm the cosmopolitan energy crisis with affordable investment capital costs. Present research highlights production and characterization of lipids by a newly isolated oleaginous bacterium, Sphingomonas sp. EGY1 DSM 29616 through an eco-friendly approach. Only sweet whey [42.1% (v/v)] in tap water was efficiently used as a growth medium and lipid production medium to encourage cell growth and trigger lipid accumulation simultaneously...
July 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28623484/identification-of-mycobacterium-species-by-maldi-tof-mass-spectrometry
#10
M Neuschlova, M Vladarova, J Kompanikova, V Sadlonova, E Novakova
Matrix-assisted laser desorption ionization - time-of-flight (MALDI-TOF) mass spectrometry enables to identify microorganisms by comparison of the protein content with reference spectra in the database. The aim of this study was to evaluate the efficacy of phenotypic identification of mycobacteria by MALDI-TOF mass spectrometry in laboratory practice. Seventy five isolates of mycobacteria were identified by molecular and phenotypic method, and the results were compared by MALDI-TOF. For MALDI-TOF, material was processed according to the Bruker Daltonics protocol and Mycobacterial Library database version 2...
June 17, 2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28620662/hexagonal-boron-nitride-nanosheets-as-a-multifunctional-background-free-matrix-to-detect-small-molecules-and-complicated-samples-by-maldi-mass-spectrometry
#11
Jianing Wang, Jie Sun, Jiyun Wang, Huihui Liu, Jinjuan Xue, Zongxiu Nie
Here we report the innovation of using hexagonal boron nitride (h-BN) nanosheets as the first background-free matrix among the full laser pulse energy range for the analysis and imaging of small molecule metabolites and as an adsorbent for the enrichment of samples. Due to its totally free background and high efficiency as an adsorbent and matrix, h-BN has promising prospects in metabolomics, MALDI imaging, and environmental analysis.
June 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28613836/design-and-performance-of-a-novel-interface-for-combined-matrix-assisted-laser-desorption-ionization-at-elevated-pressure-and-electrospray-ionization-with-orbitrap-mass-spectrometry
#12
Mikhail E Belov, Shane R Ellis, Marialaura Dilillo, Martin R L Paine, William F Danielson, Gordon A Anderson, Eric L De Graaf, Gert B Eijkel, Ron M A Heeren, Liam A McDonnell
Matrix-Assisted Laser Desorption Ionization, MALDI, has been increasingly used in a variety of biomedical applications, including tissue imaging of clinical tissue samples, and in drug discovery and development. These studies strongly depend on the performance of the analytical instrumentation and would drastically benefit from improved sensitivity, reproducibility and mass / spatial resolution. In this work, we report on a novel combined MALDI/ESI interface, which was coupled to different Orbitrap mass spectrometers (Elite™ and Q Exactive™ Plus) and extensively characterized with peptide and protein standards, and in tissue imaging experiments...
June 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28613832/monitoring-the-on-surface-synthesis-of-graphene-nanoribbons-by-mass-spectrometry
#13
Wen Zhang, Zongping Chen, Bo Yang, Xiao-Ye Wang, Reinhard Berger, Akimitsu Narita, Gabriela Borin Barin, Pascal Ruffieux, Roman Fasel, Xinliang Feng, Hans Joachim Räder, Klaus Müllen
We present a mass spectrometric approach to monitor and characterize the intermediates of graphene nanoribbon (GNR) formation by chemical vapor deposition (CVD) on top of Au(111) surfaces. Information regarding the repeating units, lengths, and termini can be obtained directly from the surface sample by a modified matrix assisted laser desorption/ionization (MALDI) method. The mass spectrometric results reveal ample oxidative side reactions under CVD conditions which can, however, be diminished drastically by introduction of protective H2 gas at ambient pressure...
June 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28609453/evaluation-of-a-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-assisted-selective-broth-method-to-screen-for-vancomycin-resistant-enterococci-in-patients-at-high-risk
#14
Tsi-Shu Huang, Susan Shin-Jung Lee, Chia-Chien Lee, Chiu-Yen Chen, Fang-Chen Chen, Bao-Chen Chen, Cheng Len Sy, Kuan-Sheng Wu
BACKGROUND: Bile esculin azide with vancomycin (BEAV) medium is a sensitive, but slightly less specific method for vancomycin-resistant enterococci (VRE) screening. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of clinical pathogens. This study aimed to assess the performance of a novel combination screening test for VRE, using BEAV broth combined with MALDI-TOF MS. MATERIALS AND METHODS: Clinical specimens were collected from patients at risk of VRE carriage, and tested by the novel combination method, using selective BEAV broth culture method followed by MALDI-TOF MS identification (SBEAVM)...
2017: PloS One
https://www.readbyqxmd.com/read/28608657/maldi-tof-ms-fingerprinting-provides-evidence-of-urosepsis-caused-by-aerococcus-urinae
#15
Jieun Kim, Sung Kuk Hong, Myungsook Kim, Dongeun Yong, Kyungwon Lee
Urosepsis due to Aerococcus urinae is rare in clinical settings with only a few of reported cases worldwide by 16S rRNA sequencing. Here we report a case of sepsis caused by A. urinae in a 86 year-old male with complicated urinary tract infection which was confirmed through peptide mass fingerprinting of matrix-assisted laser desorption ionization time of flight mass spectrometry.
May 23, 2017: Infection & Chemotherapy
https://www.readbyqxmd.com/read/28608323/comparison-of-two-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-systems-for-the-identification-of-clinical-filamentous-fungi
#16
Yanfei Huang, Mingxin Zhang, Min Zhu, Mei Wang, Yufeng Sun, Haitong Gu, Jingjing Cao, Xue Li, Shaoya Zhang, Jinglin Wang, Xinxin Lu
Infections caused by filamentous fungi have become a health concern, and require rapid and accurate identification in order for effective treatment of the pathogens. To compare the performance of two MALDI-TOF MS systems (Bruker Microflex LT and Xiamen Microtyper) in the identification of filamentous fungal species. A total of 374 clinical filamentous fungal isolates sequentially collected in the Clinical Laboratory at the Beijing Tongren Hospital between January 2014 and December 2015 were identified by traditional phenotypic methods, Bruker Microflex LT and Xiamen Microtyper MALDI-TOF MS, respectively...
July 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28604859/comment-on-non-linear-photoelectron-effect-contributes-to-the-formation-of-negative-matrix-ions-in-uv-maldi
#17
Richard Knochenmuss
Alonso and Zenobi (AZ) recently claimed "a comprehensive theoretical description of negative ion formation in UV-MALDI" (Phys. Chem. Chem. Phys., 2016, 18, 19574). Emphasizing photoelectrons, it is found to be unphysical in several respects, including violation of charge and mass conservation, and in the treatment of ablation, expansion and electron capture. It is not internally consistent, and ions created by the photoelectron mechanism are given artificial preference. Although AZ claimed the "first proposal for a comprehensive theoretical description of negative ion formation in UV-MALDI", the Coupled Physical and Chemical Dynamics model has successfully reproduced a number of phenomena relevant to negative ion production over many years...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28600691/in-situ-monitoring-of-molecular-changes-during-cell-differentiation-processes-in-marine-macroalgae-through-mass-spectrometric-imaging
#18
Ralf W Kessler, Anna C Crecelius, Ulrich S Schubert, Thomas Wichard
Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was employed to discriminate between cell differentiation processes in macroalgae. One of the key developmental processes in the algal life cycle is the production of germ cells (gametes and zoids). The gametogenesis of the marine green macroalga Ulva mutabilis (Chlorophyta) was monitored by metabolomic snapshots of the surface, when blade cells differentiate synchronously into gametangia and giving rise to gametes. To establish MSI for macroalgae, dimethylsulfoniopropionate (DMSP), a known algal osmolyte, was determined...
June 10, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28594947/mass-spectrometry-based-serum-peptidome-profiling-accurately-and-reliably-predicts-outcomes-of-pemetrexed-plus-platinum-chemotherapy-in-patients-with-advanced-lung-adenocarcinoma
#19
Lin Wang, Chuanhao Tang, Bin Xu, Lin Yang, Lili Qu, Liangliang Li, Xiaoyan Li, Weixia Wang, Haifeng Qin, Hongjun Gao, Kun He, Xiaoqing Liu
BACKGROUND: Although pemetrexed plus cis/carboplatin has become the most effective chemotherapy regimen for patients with advanced lung adenocarcinoma, predictive biomarkers are not yet available, and new tools to identify chemosensitive patients who would likely benefit from this treatment are desperately needed. In this study, we constructed and validated predictive peptide models using the serum peptidome profiles of two datasets. METHODS: One hundred eighty-three patients treated with first-line platinum-based pemetrexed treatment for advanced lung adenocarcinoma were retrospectively enrolled and randomized into the training (n = 92) or validation (n = 91) set, and pre-treatment serum samples were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and ClinProTools software...
2017: PloS One
https://www.readbyqxmd.com/read/28592553/accurate-and-rapid-differentiation-of-acinetobacter-baumannii-strains-by-raman-spectroscopy-a-comparative-study
#20
Meron Ghebremedhin, Rae Heitkamp, Shubha Yesupriya, Bradford Clay, Nicole J Crane
In recent years matrix-assisted laser ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become the standard for routine bacterial species identification due to its rapidity and low costs for consumables compared to traditional DNA-based methods. However, it has been observed that some bacterial species such as Acinetobacter baumannii strains cannot be reliably identified using mass spectrometry (MS). Raman spectroscopy is a rapid technique, as fast as MALDI-TOF, and has been shown to accurately identify bacterial strains and species...
June 7, 2017: Journal of Clinical Microbiology
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