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"Mass spectrometry"

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https://www.readbyqxmd.com/read/28813020/nine-new-triterpene-glycosides-magnumosides-a%C3%A2-a%C3%A2-b%C3%A2-b%C3%A2-c%C3%A2-c%C3%A2-and-c%C3%A2-from-the-vietnamese-sea-cucumber-neothyonidium-massinium-magnum-structures-and-activities-against-tumor-cells-independently-and-in-synergy-with-radioactive-irradiation
#1
Alexandra S Silchenko, Anatoly I Kalinovsky, Sergey A Avilov, Vladimir I Kalinin, Pelageya V Andrijaschenko, Pavel S Dmitrenok, Ekaterina A Chingizova, Svetlana P Ermakova, Olesya S Malyarenko, Tatyana N Dautova
Nine new sulfated triterpene glycosides, magnumosides A₁ (1), A₂ (2), A₃ (3), A₄ (4), B₁ (5), B₂ (6), C₁ (7), C₂ (8) and C₄ (9) as well as a known colochiroside B₂ (10) have been isolated from the tropical Indo-West Pacific sea cucumber Neothynidium (=Massinium) magnum (Phyllophoridae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of new glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. All the isolated new glycosides were characterized by the non-holostane type lanostane aglycones having 18(16)-lactone and 7(8)-double bond and differed from each other by the side chains and carbohydrate moieties structures...
August 16, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28812992/endolysosomal-degradation-of-allergenic-ole-e-1-like-proteins-analysis-of-proteolytic-cleavage-sites-revealing-t-cell-epitope-containing-peptides
#2
Sabrina Wildner, Brigitta Elsässer, Teresa Stemeseder, Peter Briza, Wai Tuck Soh, Mayte Villalba, Jonas Lidholm, Hans Brandstetter, Gabriele Gadermaier
Knowledge of the susceptibility of proteins to endolysosomal proteases provides valuable information on immunogenicity. Though Ole e 1-like proteins are considered relevant allergens, little is known about their immunogenic properties and T cell epitopes. Thus, six representative molecules, i.e., Ole e 1, Fra e 1, Sal k 5, Che a 1, Phl p 11 and Pla l 1, were investigated. Endolysosomal degradation and peptide generation were simulated using microsomal fractions of JAWS II dendritic cells. Kinetics and peptide patterns were evaluated by gel electrophoresis and mass spectrometry...
August 16, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28812749/radical-driven-processes-within-a-peptidic-sequence-of-type-i-collagen-upon-single-photon-ionisation-in-the-gas-phase
#3
Lucas Schwob, Mathieu Lalande, Dmitrii Egorov, Jimmy Rangama, Ronnie Hoekstra, Violaine Vizcaino, Thomas Schlathölter, Jean-Christophe Poully
We report on an experimental single-photon absorption study on gas-phase protonated collagen peptides employing a combination of mass spectrometry and synchrotron radiation. Partial ion yields for the main photoabsorption products vary steadily with photon energy over the range from 14 to 545 eV. At low energy, non-dissociative photoionisation competes with neutral molecule loss from the precursor ion, whereas fragmentation of the peptide backbone dominates at soft X-ray energies. Neutral molecule losses from the ionised peptide are found to have low energy barriers and most likely involve amino-acid residue side-chains with radical character, in particular aspartic acid...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812349/purification-and-characterization-of-latent-polyphenol-oxidase-from-apricot-prunus-armeniaca-l
#4
Ala Eddine Derardja, Matthias Pretzler, Ioannis Kampatsikas, Malika Barkat, Annette Rompel
Polyphenol oxidase from apricot (Prunus armeniaca) (PaPPO) was purified in its latent form (L-PaPPO) and the molecular weight was determined to 63 kDa by SDS-PAGE. L-PaPPO was activated in the presence of substrate at low pH. The activity was enhanced by CuSO4 and low concentrations (≤ 2 mM) of SDS. PaPPO has its pH and temperature optimum at pH 4.5 and 45 °C for catechol as the substrate. It showed diphenolase activity and highest affinity toward 4-methylcatechol (KM = 2.0 mM) and chlorogenic acid (KM = 2...
August 16, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28812241/plasma-glycoproteomic-study-of-therapeutic-hypothermia-reveals-novel-markers-predicting-neurologic-outcome-post-cardiac-arrest
#5
Wenjun Deng, Jing Cao, Lei Chen, David McMullin, James L Januzzi, Ferdinando S Buonanno, Eng H Lo, MingMing Ning
Therapeutic hypothermia (TH) is a neuroprotective treatment post-cardiac arrest but is grossly underutilized. After TH induction, traditional biomarkers and parameters can no long predict clinical outcome due to a lack of understanding of hypothermic response. Innovative approaches to better understand the clinical effect of TH will help to prognosticate outcome and expand beneficial population. Protein glycosylation is an important extracellular post-translational modification, regulating various extracellular signaling pathways...
August 15, 2017: Translational Stroke Research
https://www.readbyqxmd.com/read/28812177/host-plant-species-differentiation-in-a-polyphagous-moth-olfaction-is-enough
#6
Lucie Conchou, Peter Anderson, Göran Birgersson
Polyphagous herbivorous insects need to discriminate suitable from unsuitable host plants in complex plant communities. While studies on the olfactory system of monophagous herbivores have revealed close adaptations to their host plant's characteristic volatiles, such adaptive fine-tuning is not possible when a large diversity of plants is suitable. Instead, the available literature on polyphagous herbivore preferences suggests a higher level of plasticity, and a bias towards previously experienced plant species...
August 15, 2017: Journal of Chemical Ecology
https://www.readbyqxmd.com/read/28812082/a-broader-view-on-ion-heating-in-traveling-wave-devices-using-fragmentation-of-csi-clusters-and-extent-of-h%C3%AB-migration-as-molecular-thermometers
#7
Frederik Lermyte, Frank Sobott
Electron transfer dissociation (ETD) is becoming increasingly important in mass spectrometry-based analysis of peptides and proteins. Supplemental collisional activation of undissociated electron transfer products can significantly increase fragmentation yield and sequence coverage, but hydrogen rearrangements - specifically, transfer of a hydrogen radical from a c to a z fragment - lead to distorted isotope distributions and increased potential for signal overlap. Concomitant collisional activation during the ion/ion reaction significantly reduces these rearrangements, but, in ion traps, also leads to lower reaction rates and reduced overlap of anion and cation clouds...
August 16, 2017: Analyst
https://www.readbyqxmd.com/read/28811980/erap1-overexpression-in-hpv-induced-malignancies-a-possible-novel-immune-evasion-mechanism
#8
Alina Steinbach, Jan Winter, Miriam Reuschenbach, Renata Blatnik, Alexandra Klevenz, Miriam Bertrand, Stephanie Hoppe, Magnus von Knebel Doeberitz, Agnieszka K Grabowska, Angelika B Riemer
Immune evasion of tumors poses a major challenge for immunotherapy. For human papillomavirus (HPV)-induced malignancies, multiple immune evasion mechanisms have been described, including altered expression of antigen processing machinery (APM) components. These changes can directly influence epitope presentation and thus T-cell responses against tumor cells. To date, the APM had not been studied systematically in a large array of HPV(+) tumor samples. Therefore in this study, systematic expression analysis of the APM was performed on the mRNA and protein level in a comprehensive collection of HPV16(+) cell lines...
2017: Oncoimmunology
https://www.readbyqxmd.com/read/28811827/pharmacodynamics-and-medicinal-chemistry-of-an-external-chinese-herbal-formula-for-mammary-precancerous-lesions
#9
Ruixue Chen, Guijuan Zhang, Yi Ma, Fengjie Bie, Hongxia Fan, Min Ma
Ruyan Neixiao Cream (RYNXC) is a traditional Chinese herbal formula for treating mammary precancerous disease. This study was carried out to investigate in vivo anticancer effect of RYNXC and multiple constituents. 32 virginal Sprague-Dawley rats were randomly divided into blank control group (BC), mammary precancer models group (MODEL), tamoxifen group (TAM), and Ruyan Neixiao Cream group (RYNXC). TAM was intervened by tamoxifen; RYNXC was intervened by Ruyan Neixiao Cream. The chromatographic separation was performed by high performance liquid chromatography (HPLC) coupled with mass spectrometry (MS)...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
https://www.readbyqxmd.com/read/28811661/myst2-kat7-histone-acetyltransferase-interaction-proteomics-reveals-tumour-suppressor-niam-as-a-novel-binding-partner-in-embryonic-stem-cells
#10
Mercedes Pardo, Lu Yu, Shihpei Shen, Peri Tate, Daniel Bode, Blake L Letney, Dawn E Quelle, William Skarnes, Jyoti S Choudhary
MYST histone acetyltransferases have crucial functions in transcription, replication and DNA repair and are hence implicated in development and cancer. Here we characterise Myst2/Kat7/Hbo1 protein interactions in mouse embryonic stem cells by affinity purification coupled to mass spectrometry. This study confirms that in embryonic stem cells Myst2 is part of H3 and H4 histone acetylation complexes similar to those described in somatic cells. We identify a novel Myst2-associated protein, the tumour suppressor protein Niam (Nuclear Interactor of ARF and Mdm2)...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811602/identification-of-ciguatoxins-in-a-shark-involved-in-a-fatal-food-poisoning-in-the-indian-ocean
#11
Jorge Diogène, Laia Reverté, Maria Rambla-Alegre, Vanessa Del Río, Pablo de la Iglesia, Mònica Campàs, Oscar Palacios, Cintia Flores, Josep Caixach, Christian Ralijaona, Iony Razanajatovo, Agathe Pirog, Hélène Magalon, Nathalie Arnich, Jean Turquet
Severe food poisoning events after the consumption of sharks have been reported since the 1940s; however, there has been no clear understanding of their cause. Herein, we report for the first time the presence of ciguatoxins (CTXs) in sharks. The identification by mass spectrometry of CTXs, including two new analogues, in a bull shark (Carcharhinus leucas) that was consumed by humans, causing the poisoning and death of 11 people in Madagascar in 2013 is described. Typical neurotoxic ciguatera symptoms were recorded in patients, and toxicological assays on extracts of the shark demonstrated CTX-like activity...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811596/complete-alanine-scanning-of-the-escherichia-coli-rbsb-ribose-binding-protein-reveals-residues-important-for-chemoreceptor-signaling-and-periplasmic-abundance
#12
Artur Reimer, Vitali Maffenbeier, Manupriyam Dubey, Vladimir Sentchilo, Diogo Tavares, Manuel Hernandez Gil, Siham Beggah, Jan Roelof van der Meer
The Escherichia coli RbsB ribose binding protein has been used as a scaffold for predicting new ligand binding functions through in silico modeling, yet with limited success and reproducibility. In order to possibly improve the success of predictive modeling on RbsB, we study here the influence of individual residues on RbsB-mediated signaling in a near complete library of alanine-substituted RbsB mutants. Among a total of 232 tested mutants, we found 10 which no longer activated GFPmut2 reporter expression in E...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811589/patients-with-igg1-anti-red-blood-cell-autoantibodies-show-aberrant-fc-glycosylation
#13
Myrthe E Sonneveld, Masja de Haas, Carolien Koeleman, Noortje de Haan, Sacha S Zeerleder, Peter C Ligthart, Manfred Wuhrer, C Ellen van der Schoot, Gestur Vidarsson
Autoimmune hemolytic anemia (AIHA) is a potentially severe disease in which red blood cells (RBC) are destroyed by IgG anti-RBC autoantibodies which can lead to hemolysis. We recently found IgG Fc-glycosylation towards platelet and RBC alloantigens to be skewed towards decreased fucosylation, increased galactosylation and sialylation. The lowered core-fucosylation increases the affinity of the pathogenic alloantibodies to FcγRIIIa/b, and hence RBC destruction. It is known that in autoimmune diseases plasma IgG1 galactosylation and sialylation are lowered, but Fc-glycosylation of RBC-specific autoantibodies has never been thoroughly analyzed...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811582/a-new-class-of-hybrid-secretion-system-is-employed-in-pseudomonas-amyloid-biogenesis
#14
Sarah L Rouse, William J Hawthorne, Jamie-Lee Berry, Dror S Chorev, Sandra A Ionescu, Sebastian Lambert, Fisentzos Stylianou, Wiebke Ewert, Uma Mackie, R Marc L Morgan, Daniel Otzen, Florian-Alexander Herbst, Per H Nielsen, Morten Dueholm, Hagan Bayley, Carol V Robinson, Stephen Hare, Stephen Matthews
Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits for construction of a biofilm matrix. The secretion of bacterial functional amyloid requires a bespoke outer-membrane protein channel through which unfolded amyloid substrates are translocated. Here, we combine X-ray crystallography, native mass spectrometry, single-channel electrical recording, molecular simulations and circular dichroism measurements to provide high-resolution structural insight into the functional amyloid transporter from Pseudomonas, FapF...
August 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28811533/plasma-metabolomics-profiling-of-maintenance-hemodialysis-based-on-capillary-electrophoresis-time-of-flight-mass-spectrometry
#15
Shuxin Liu, Lichao Wang, Chunxiu Hu, Xin Huang, Hong Liu, Qiuhui Xuan, Xiaohui Lin, Xiaojun Peng, Xin Lu, Ming Chang, Guowang Xu
Uremia has been a rapidly increasing health problem in China. Hemodialysis (HD) is the main renal replacement therapy for uremia. The results of large-scale clinical trials have shown that the HD pattern is crucial for long-term prognosis of maintenance hemodialysis (MHD) in uremic patients. Plasma metabolism is very important for revealing the biological insights linked to the therapeutic effects of the HD pattern on uremia. Alteration of plasma metabolites in uremic patients in response to HD therapy has been reported...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811532/protein-expression-changes-caused-by-spaceflight-as-measured-for-18-russian-cosmonauts
#16
Irina M Larina, Andrew J Percy, Juncong Yang, Christoph H Borchers, Andrei M Nosovsky, Anatoli I Grigoriev, Evgeny N Nikolaev
The effects of spaceflight on human physiology is an increasingly studied field, yet the molecular mechanisms driving physiological changes remain unknown. With that in mind, this study was performed to obtain a deeper understanding of changes to the human proteome during space travel, by quantitating a panel of 125 proteins in the blood plasma of 18 Russian cosmonauts who had conducted long-duration missions to the International Space Station. The panel of labeled prototypic tryptic peptides from these proteins covered a concentration range of more than 5 orders of magnitude in human plasma...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811511/from-metabolome-to-phenotype-gc-ms-metabolomics-of-developing-mutant-barley-seeds-reveals-effects-of-growth-temperature-and-genotype
#17
Bekzod Khakimov, Morten Arendt Rasmussen, Rubini Maya Kannangara, Birthe Møller Jespersen, Lars Munck, Søren Balling Engelsen
The development of crop varieties tolerant to growth temperature fluctuations and improved nutritional value is crucial due to climate change and global population growth. This study investigated the metabolite patterns of developing barley seed as a function of genotype and growth temperature for ideal vegetable protein production and for augmented β-glucan production. Seeds from three barley lines (Bomi, lys3.a and lys5.f) were sampled eight times during grain filling and analysed for metabolites using gas chromatography-mass spectrometry (GC-MS)...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811501/characterisation-of-sterol-biosynthesis-and-validation-of-14%C3%AE-demethylase-as-a-drug-target-in-acanthamoeba
#18
Scott Thomson, Christopher A Rice, Tong Zhang, RuAngelie Edrada-Ebel, Fiona L Henriquez, Craig W Roberts
The soil amoebae Acanthamoeba causes Acanthamoeba keratitis, a severe sight-threatening infection of the eye and the almost universally fatal granulomatous amoebic encephalitis. More effective treatments are required. Sterol biosynthesis has been effectively targeted in numerous fungi using azole compounds that inhibit the cytochrome P450 enzyme sterol 14α-demethylase. Herein, using Gas Chromatography Mass Spectrometry (GCMS), we demonstrate that the major sterol of Acanthamoeba castellanii is ergosterol and identify novel putative precursors and intermediate sterols in its production...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811141/the-pharmacokinetic-profile-of-synthetic-cathinones-in-a-pregnancy-model
#19
Lauren G Strange, Kerri Kochelek, Robert Keasling, Stacy D Brown, Brooks B Pond
In recent years, the abuse of synthetic cathinones or 'bath salts' has become a major public health concern. Although these compounds were initially sold legally and labeled "not for human consumption", the 'bath salts' are psychostimulants, with similar structures and pharmacologic mechanisms to cocaine, the amphetamines, and 3,4 methylendioxymethamphetamine (MDMA, Molly, or Ecstasy). The reported use of these substances by women of child-bearing age highlights the necessity of studies seeking to delineate risks of prenatal exposure...
August 12, 2017: Neurotoxicology and Teratology
https://www.readbyqxmd.com/read/28811136/determination-of-ghb-and-ghb-%C3%AE-o-glucuronide-in-hair-of-three-narcoleptic-patients-comparison-between-single-and-chronic-ghb-exposure
#20
Lena-Maria Mehling, Xin Wang, Sys-Stybe Johansen, Annika Spottke, Anna Heidbreder, Peter Young, Burkhard Madea, Cornelius Hess
Gamma-hydroxybutyric acid (GHB) can be used as a knock-out drug in drug facilitated crime (DFC). Due to its rapid metabolism and resulting narrow detection window, uncovering GHB use in DFC still constitutes a problem. In this experiment we determined the GHB and GHB-β-O-glucuronide (GHB-Gluc) concentrations in hair samples after single and chronic GHB exposures. Hair samples of three narcoleptic patients therapeutically taking sodium oxybate (GHB-sodium-salt) were collected. Patients 1 (P1) and 2 (P2) took the medication for nine and six years, respectively...
July 31, 2017: Forensic Science International
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