134 research outputs found
Ordered logistic regression assessing predictors of post-stress hyperacusis (ULL 2 kHz), including interacting or confounding effects of age, gender, ear wax and hearing loss (only PTA).
<p>All logistic regression analyses were adjusted for hearing loss and ear wax. PL (left) and PR (right) are overall tests of variables included in the estimated model.</p
Comparison of Extraction Methods for the Comprehensive Analysis of Mouse Brain Proteome using Shotgun-based Mass Spectrometry
This study compares 16 different extraction methods for
the comprehensive extraction of mouse brain proteome in combination
with âshotgunâ-based mass spectrometry (MS). Membrane
proteins (MPs) are responsible for a large part of the regulatory
functions of the cell and are therefore of great interest to extract
and analyze. Sixteen protein extraction protocols were evaluated in
regards to protein yield and number of identified proteins with emphasis
on MPs. The extracted proteins were delipidated, on-filter digested,
and analyzed by reversed phase nanoliquid chromatography (RP-nanoLC)
in combination with electrospray ionization (ESI) tandem mass spectrometry
(MS/MS) using a 7 T hybrid LTQ-FT mass spectrometer. Detergent-based
lysis buffers showed higher efficiencies and yields in the extraction
of proteins from the brain tissue compared to solubilization with
organic solvents or organic acids. The detergent octyl-ÎČ-d-glucopyranoside gave the highest number of identified proteins
(541) as well as numbers and percentages of identified MPs (29%).
Detergent-based protocols are the best sample preparation tools for
central nervous system (CNS) tissue and can readily be applied to
screen for candidate biomarkers of neurological diseases
Comparison of Extraction Methods for the Comprehensive Analysis of Mouse Brain Proteome using Shotgun-based Mass Spectrometry
This study compares 16 different extraction methods for
the comprehensive extraction of mouse brain proteome in combination
with âshotgunâ-based mass spectrometry (MS). Membrane
proteins (MPs) are responsible for a large part of the regulatory
functions of the cell and are therefore of great interest to extract
and analyze. Sixteen protein extraction protocols were evaluated in
regards to protein yield and number of identified proteins with emphasis
on MPs. The extracted proteins were delipidated, on-filter digested,
and analyzed by reversed phase nanoliquid chromatography (RP-nanoLC)
in combination with electrospray ionization (ESI) tandem mass spectrometry
(MS/MS) using a 7 T hybrid LTQ-FT mass spectrometer. Detergent-based
lysis buffers showed higher efficiencies and yields in the extraction
of proteins from the brain tissue compared to solubilization with
organic solvents or organic acids. The detergent octyl-ÎČ-d-glucopyranoside gave the highest number of identified proteins
(541) as well as numbers and percentages of identified MPs (29%).
Detergent-based protocols are the best sample preparation tools for
central nervous system (CNS) tissue and can readily be applied to
screen for candidate biomarkers of neurological diseases
Ordered logistic regression assessing predictors of post-stress hyperacusis (ULL 4 kHz), including interacting or confounding effects of age, gender, ear wax and hearing loss (only PTA).
<p>All logistic regression analyses were adjusted for hearing loss and ear wax. PL (left) and PR (right) are overall tests of variables included in the estimated model.</p
Evaluation of the Orbitrap Mass Spectrometer for the Molecular Fingerprinting Analysis of Natural Dissolved Organic Matter
We investigated the
application of the LTQ-Orbitrap mass spectrometer
(LTQ-Velos Pro, Thermo Fisher) for resolving complex mixtures of natural
aquatic dissolved organic matter (DOM) and compared this technique
to the more established state-of-the-art technique, Fourier transform
ion cyclotron resonance mass spectrometry (FTICR-MS, Bruker Daltonics),
in terms of the distribution of molecular masses detected and the
reproducibility of the results collected. The Orbitrap was capable
of excellent reproducibility: BrayâCurtis dissimilarity between
duplicate measurements was 2.85 ± 0.42% (mean ± standard
deviation). The Orbitrap was also capable of the detection of most
major ionizable organic molecules in typical aquatic mixtures, with
the exception of most sulfur and phosphorus containing masses. This
result signifies that the Orbitrap is an appropriate technique for
the investigation of very subtle biogeochemical processing of bulk
DOM. The lower costs (purchase and maintenance) and wider availability
of Orbitrap mass spectrometers in university departments means that
the tools necessary for research into DOM processing at the molecular
level should be accessible to a much wider group of scientists than
before. The main disadvantage of the technique is that substantially
fewer molecular formulas can be resolved from a complex mixture (roughly
one
third as many), meaning some loss of information. In balance, most
biogeochemical studies that aim at molecularly fingerprinting the
source of natural DOM could be satisfactorily carried out with Orbitrap
mass spectrometry. For more targeted metabolomic studies where individual
compounds are traced through natural systems, FTICR-MS remains advantageous
Evaluation of the Orbitrap Mass Spectrometer for the Molecular Fingerprinting Analysis of Natural Dissolved Organic Matter
We investigated the
application of the LTQ-Orbitrap mass spectrometer
(LTQ-Velos Pro, Thermo Fisher) for resolving complex mixtures of natural
aquatic dissolved organic matter (DOM) and compared this technique
to the more established state-of-the-art technique, Fourier transform
ion cyclotron resonance mass spectrometry (FTICR-MS, Bruker Daltonics),
in terms of the distribution of molecular masses detected and the
reproducibility of the results collected. The Orbitrap was capable
of excellent reproducibility: BrayâCurtis dissimilarity between
duplicate measurements was 2.85 ± 0.42% (mean ± standard
deviation). The Orbitrap was also capable of the detection of most
major ionizable organic molecules in typical aquatic mixtures, with
the exception of most sulfur and phosphorus containing masses. This
result signifies that the Orbitrap is an appropriate technique for
the investigation of very subtle biogeochemical processing of bulk
DOM. The lower costs (purchase and maintenance) and wider availability
of Orbitrap mass spectrometers in university departments means that
the tools necessary for research into DOM processing at the molecular
level should be accessible to a much wider group of scientists than
before. The main disadvantage of the technique is that substantially
fewer molecular formulas can be resolved from a complex mixture (roughly
one
third as many), meaning some loss of information. In balance, most
biogeochemical studies that aim at molecularly fingerprinting the
source of natural DOM could be satisfactorily carried out with Orbitrap
mass spectrometry. For more targeted metabolomic studies where individual
compounds are traced through natural systems, FTICR-MS remains advantageous
Comprehensive Proteomic Study of the Antiproliferative Activity of a Polyphenol-Enriched Rosemary Extract on Colon Cancer Cells Using Nanoliquid ChromatographyâOrbitrap MS/MS
In this work, a proteomics strategy
based on nanoliquid chromatographyâtandem
mass spectrometry (nano-LCâMS/MS) using an Orbitrap high-resolution
mass spectrometer together with stable isotope dimethyl labeling (DML)
is applied to quantitatively examine relative changes in the protein
fraction of HT-29 human colon cancer cells treated with different
concentrations of a polyphenol-enriched rosemary extract over the
time. The major objective of this study was to gain insights into
the antiproliferative mechanisms induced by rosemary polyphenols.
Using this methodology, 1909 and 698 proteins were identified and
quantified in cell extracts. The polyphenol-enriched rosemary extract
treatment changed the expression of several proteins in a time- and
concentration-dependent manner. Most of the altered proteins are implicated
in the activation of Nrf2 transcription factor and the unfolded protein
response. In conclusion, rosemary polyphenols induced proteomic changes
that were related to the attenuation of aggresome formation and activation
of autophagy to alleviate cellular stress
Evaluation of the Orbitrap Mass Spectrometer for the Molecular Fingerprinting Analysis of Natural Dissolved Organic Matter
We investigated the
application of the LTQ-Orbitrap mass spectrometer
(LTQ-Velos Pro, Thermo Fisher) for resolving complex mixtures of natural
aquatic dissolved organic matter (DOM) and compared this technique
to the more established state-of-the-art technique, Fourier transform
ion cyclotron resonance mass spectrometry (FTICR-MS, Bruker Daltonics),
in terms of the distribution of molecular masses detected and the
reproducibility of the results collected. The Orbitrap was capable
of excellent reproducibility: BrayâCurtis dissimilarity between
duplicate measurements was 2.85 ± 0.42% (mean ± standard
deviation). The Orbitrap was also capable of the detection of most
major ionizable organic molecules in typical aquatic mixtures, with
the exception of most sulfur and phosphorus containing masses. This
result signifies that the Orbitrap is an appropriate technique for
the investigation of very subtle biogeochemical processing of bulk
DOM. The lower costs (purchase and maintenance) and wider availability
of Orbitrap mass spectrometers in university departments means that
the tools necessary for research into DOM processing at the molecular
level should be accessible to a much wider group of scientists than
before. The main disadvantage of the technique is that substantially
fewer molecular formulas can be resolved from a complex mixture (roughly
one
third as many), meaning some loss of information. In balance, most
biogeochemical studies that aim at molecularly fingerprinting the
source of natural DOM could be satisfactorily carried out with Orbitrap
mass spectrometry. For more targeted metabolomic studies where individual
compounds are traced through natural systems, FTICR-MS remains advantageous
Comprehensive Proteomic Study of the Antiproliferative Activity of a Polyphenol-Enriched Rosemary Extract on Colon Cancer Cells Using Nanoliquid ChromatographyâOrbitrap MS/MS
In this work, a proteomics strategy
based on nanoliquid chromatographyâtandem
mass spectrometry (nano-LCâMS/MS) using an Orbitrap high-resolution
mass spectrometer together with stable isotope dimethyl labeling (DML)
is applied to quantitatively examine relative changes in the protein
fraction of HT-29 human colon cancer cells treated with different
concentrations of a polyphenol-enriched rosemary extract over the
time. The major objective of this study was to gain insights into
the antiproliferative mechanisms induced by rosemary polyphenols.
Using this methodology, 1909 and 698 proteins were identified and
quantified in cell extracts. The polyphenol-enriched rosemary extract
treatment changed the expression of several proteins in a time- and
concentration-dependent manner. Most of the altered proteins are implicated
in the activation of Nrf2 transcription factor and the unfolded protein
response. In conclusion, rosemary polyphenols induced proteomic changes
that were related to the attenuation of aggresome formation and activation
of autophagy to alleviate cellular stress
Result of shotgun analyses of gel fractionated cat sera samples.
<p>Result of shotgun analyses of gel fractionated cat sera samples.</p
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