scholarly journals The volatiles of pathogenic and nonpathogenic mycobacteria and related bacteria

2012 ◽  
Vol 8 ◽  
pp. 290-299 ◽  
Author(s):  
Thorben Nawrath ◽  
Georgies F Mgode ◽  
Bart Weetjens ◽  
Stefan H E Kaufmann ◽  
Stefan Schulz
Keyword(s):  
Rational Design ◽  
Closed Loop ◽  
Growth Curves ◽  
Gas Chromatography Mass Spectrometry ◽  
Absolute Amount ◽  
Liquid Media ◽  
Diagnostic Measures ◽  
Fatty Acid Derivatives ◽  
Wide Range ◽  
Volatile Production

Volatiles released by pathogenic and nonpathogenic mycobacteria, as well as by mycobacteria-relatedNocardiaspp., were analyzed. Bacteria were cultivated on solid and in liquid media, and headspace samples were collected at various times during the bacterial lifecycle to elucidate the conditions giving optimal volatile emission. Emitted volatiles were collected by using closed-loop stripping analysis (CLSA) and were analyzed by gas-chromatography–mass-spectrometry. A wide range of compounds was produced, although the absolute amount was small. Nevertheless, characteristic bouquets of compounds could be identified. Predominantly aromatic compounds and fatty-acid derivatives were released by pathogenic/nonpathogenic mycobacteria, while the twoNocardiaspp. (N. asteroidesandN. africana) emitted the sesquiterpene aciphyllene. PathogenicMycobacterium tuberculosisstrains grown on agar plates produced a distinct bouquet with different volatiles, while liquid cultures produce less compounds but sometimes an earlier onset of volatile production because of their steeper growth curves under this conditions. This behavior differentiatesM. tuberculosisfrom other mycobacteria, which generally produced fewer compounds in seemingly lower amounts. Knowledge of the production of volatiles byM. tuberculosiscan facilitate the rational design of alternative and faster diagnostic measures for tuberculosis.

The identification of odorous metabolites produced from algal monocultures

1995 ◽  
Vol 31 (11) ◽  
pp. 251-258 ◽  
Author(s):  
E. Cotsaris ◽  
A. Bruchet ◽  
J. Mallevialle ◽  
D. B. Bursill
Keyword(s):  
Gas Chromatography ◽  
Closed Loop ◽  
Steam Distillation ◽  
Profile Analysis ◽  
Algal Species ◽  
Gas Chromatography Mass Spectrometry ◽  
Stripping Analysis ◽  
River Seine ◽  
Wide Range ◽  
Steam Distillation Extraction

Four algal species commonly found in the River Seine were cultured for a comprehensive investigation of their odorous metabolites. Closed loop stripping analysis (CLSA), open stripping analysis (OSA) and steam distillation extraction (SDE) were used to extract and concentrate a wide range of metabolites. The odour causing compounds were identified by a combination of chemical (gas chromatography-mass spectrometry (GC-MS)) and sensory (sensory-gas chromatography (sensory-GC), flavour profile analysis (FPA)) analyses. The compounds found responsible for unpleasant odours were alkenes, saturated and unsaturated aliphatic alcohols, aldehydes, ketones, sulphides and pyrazines. Some of the odorous compounds responsible for septic and muddy/musty odours may have been of bacterial or fungal origin as the cultures were non-axenic. Sensory-GC was found to be a valuable tool in identifying compounds of very low odour thresholds, which were present at or below the detection limits of the GC-MS.

Analysis of Aromatic Amines in Industrial Wastewater by Capillary Gas Chromatography-Mass Spectrometry

2000 ◽  
Vol 35 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Francis I. Onuska ◽  
Ken A. Terry ◽  
R. James Maguire
Keyword(s):  
Gas Chromatography ◽  
Aromatic Amines ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Stationary Phases ◽  
Gas Chromatography Mass Spectrometry ◽  
Substituted Anilines ◽  
Environmental Media ◽  
Solid Phase Extraction Cartridge ◽  
Wide Range

Abstract The analysis of aromatic amines, particularly benzidines, at trace levels in environmental media has been difficult because of the lack of suitable deactivated capillary column stationary phases for gas chromatography. This report describes the use of an improved type of column as well as a method for the analysis of anilines and benzidines in water, wastewater and sewage samples. Extraction procedures are applicable to a wide range of compounds that are effectively partitioned from an aqueous matrix into methylene chloride, or onto a solid-phase extraction cartridge. The extracted analytes are also amenable to separation on a capillary gas chromatographic column and transferable to the mass spectrometer. These contaminants are converted to their N-trifluoroacetyl derivatives. Aniline and some substituted anilines, and 3,3’-dichlorobenzidine and benzidine were determined in 24-h composite industrial water, wastewater, primary sludge and final effluent samples at concentrations from 0.03 up to 2760 µg/L.

scholarly journals Rapid Determination of Ethylene Oxide and 75 VOCs in Ambient Air with Canister Sampling and Associated Growth Issues

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 35
Author(s):  
Jason Hoisington ◽  
Jason S. Herrington
Keyword(s):  
Ethylene Oxide ◽  
Rapid Determination ◽  
Complex Mixture ◽  
Ambient Air ◽  
Gas Chromatography Mass Spectrometry ◽  
Average Accuracy ◽  
Relative Standard ◽  
Wide Range ◽  
Us Epa

A canister-based sampling method along with preconcentrator-Gas chromatography-Mass Spectrometry (GC-MS) analysis was applied to ethylene oxide (EtO or EO) and 75 other volatile organic compounds (VOCs) in ambient air. Ambient air can contain a large variety of VOCs, and thorough analysis requires non-discriminatory sampling and a chromatographic method capable of resolving a complex mixture. Canister collection of whole air samples allows for the collection of a wide range of volatile compounds, while the simultaneous analysis of ethylene oxide and other VOCs allows for faster throughput than separate methods. The method presented is based on US EPA Method TO-15A and allows for the detection of EtO from 18 to 2500 pptv. The method has an average accuracy of 104% and precision of 13% relative standard deviation (RSD), with an instrument run time of 32 min. In addition, a link between canister cleanliness and ethylene oxide growth is observed, and potential mechanisms and cleaning strategies are addressed.

scholarly journals Fluorescent thermal shift-based method for detection of NF-κB binding to double-stranded DNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter D. Leitner ◽  
Ilja Vietor ◽  
Lukas A. Huber ◽  
Taras Valovka
Keyword(s):  
Dna Binding ◽  
Rational Design ◽  
Dissociation Constants ◽  
Inflammatory Diseases ◽  
Dimethyl Fumarate ◽  
Bioinformatic Analysis ◽  
Quantitative Detection ◽  
Regulatory Sequences ◽  
Wide Range ◽  
Inhibitory Drug

AbstractThe nuclear factor kappa B (NF-κB) family of dimeric transcription factors regulates a wide range of genes by binding to their specific DNA regulatory sequences. NF-κB is an important therapeutic target linked to a number of cancers as well as autoimmune and inflammatory diseases. Therefore, effective high-throughput methods for the detection of NF-κB DNA binding are essential for studying its transcriptional activity and for inhibitory drug screening. We describe here a novel fluorescence-based assay for quantitative detection of κB consensus double-stranded (ds) DNA binding by measuring the thermal stability of the NF-κB proteins. Specifically, DNA binding proficient NF-κB probes, consisting of the N-terminal p65/RelA (aa 1–306) and p50 (aa 1–367) regions, were designed using bioinformatic analysis of protein hydrophobicity, folding and sequence similarities. By measuring the SYPRO Orange fluorescence during thermal denaturation of the probes, we detected and quantified a shift in the melting temperatures (ΔTm) of p65/RelA and p50 produced by the dsDNA binding. The increase in Tm was proportional to the concentration of dsDNA with apparent dissociation constants (KD) of 2.228 × 10–6 M and 0.794 × 10–6 M, respectively. The use of withaferin A (WFA), dimethyl fumarate (DMF) and p-xyleneselenocyanate (p-XSC) verified the suitability of this assay for measuring dose-dependent antagonistic effects on DNA binding. In addition, the assay can be used to analyse the direct binding of inhibitors and their effects on structural stability of the protein probe. This may facilitate the identification and rational design of new drug candidates interfering with NF-κB functions.

scholarly journals In Vitro Incorporation of Helicobacter pylori into Candida albicans Caused by Acidic pH Stress

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 489 ◽  
Author(s):  
Kimberly Sánchez-Alonzo ◽  
Cristian Parra-Sepúlveda ◽  
Samuel Vega ◽  
Humberto Bernasconi ◽  
Víctor L. Campos ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Candida Albicans ◽  
Pcr Amplification ◽  
Growth Curves ◽  
Acidic Ph ◽  
Ph Values ◽  
16S Gene ◽  
Wide Range ◽  
H Pylori

Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facultative intracellular bacterium, can adapt to a range from pH 6 to 8. This work analyzed if H. pylori J99 can protect itself from acidic pH by entering into Candida albicans ATCC 90028. Growth curves were determined for H. pylori and C. albicans at pH 3, 4, and 7. Both microorganisms were co-incubated at the same pH values, and the presence of intra-yeast bacteria was evaluated. Intra-yeast bacteria-like bodies were detected using wet mounting, and intra-yeast binding of anti-H. pylori antibodies was detected using immunofluorescence. The presence of the H. pylori rDNA 16S gene in total DNA from yeasts was demonstrated after PCR amplification. H. pylori showed larger death percentages at pH 3 and 4 than at pH 7. On the contrary, the viability of the yeast was not affected by any of the pHs evaluated. H. pylori entered into C. albicans at all the pH values assayed but to a greater extent at unfavorable pH values (pH 3 or 4, p = 0.014 and p = 0.001, respectively). In conclusion, it is possible to suggest that H. pylori can shelter itself within C. albicans under unfavorable pH conditions.

Experiences with alluvial foundations for earth dams in the Prairie provinces

1979 ◽  
Vol 16 (2) ◽  
pp. 255-271 ◽  
Author(s):  
N. Peters ◽  
K. N. Lamb
Keyword(s):  
Rational Design ◽  
Preliminary Design ◽  
Empirical Relationships ◽  
Design Concepts ◽  
Theoretical Design ◽  
Pore Pressures ◽  
Wide Range ◽  
Thick Layers ◽  
Limited Testing ◽  
Prairie Provinces

The foundations for numerous dams in proglacial and interglacial valleys in the Prairie provinces consist of soft alluvial soils. The deposits are up to 60 m deep, and contain thick layers of clay interspersed with lenses and layers of silt, sand, and gravel.This paper describes the damsite investigation and laboratory testing required, the design methods and construction procedures used, and the foundation performance observed during and after construction. A number of empirical relationships between index tests and physical properties of the soils, which provide useful guidelines for preliminary design, are presented.The design approach has gradually evolved from an empirical design with limited testing to a more rational design based on detailed investigations and thorough instrumentation. Increased reliance is placed on observational apparatus to monitor movements and pore pressures to confirm design assumptions as construction proceeds. The theoretical design is always checked with former designs of dams that have performed satisfactorily.Safe economical dams have been constructed in spite of large deformations and high pore pressures. Two case histories illustrate the wide range in dam design for alluvial foundations. The first shows an older design cross section with modifications required to ensure a stable dam, and the second describes a recently constructed dam that incorporates many of the latest design concepts.

A closed-loop wide-range tunable mechanical resonator for energy harvesting systems

2009 ◽  
Vol 19 (9) ◽  
pp. 094004 ◽  
Author(s):  
Christian Peters ◽  
Dominic Maurath ◽  
Wolfram Schock ◽  
Florian Mezger ◽  
Yiannos Manoli
Keyword(s):  
Energy Harvesting ◽  
Closed Loop ◽  
Mechanical Resonator ◽  
Wide Range ◽  
Harvesting Systems

scholarly journals A high-throughput and sensitive methodology for the quantification of urinary 8-hydroxy-2′-deoxyguanosine: measurement with gas chromatography-mass spectrometry after single solid-phase extraction

2004 ◽  
Vol 380 (2) ◽  
pp. 541-548 ◽  
Author(s):  
Hai-Shu LIN ◽  
Andrew M. JENNER ◽  
Choon Nam ONG ◽  
Shan Hong HUANG ◽  
Matthew WHITEMAN ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Healthy Subjects ◽  
Solid Phase ◽  
Large Population ◽  
Urine Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Freeze Dried ◽  
Wide Range

8-Hydroxy-2´-deoxyguanosine (8OHdG) is a widely used biomarker for the measurement of endogenous oxidative DNA damage. A sensitive method for the quantification of 8OHdG in urine by single solid-phase extraction and GC-MS (gas chromatography with MS detection) using selective ion monitoring is described in the present study. After solid-phase extraction, samples are freeze-dried, derivatized by trimethylsilylation and analysed by GC-MS. The urinary 8OHdG was quantified using heavy isotope dilution with [18O]8OHdG. The recovery of 8OHdG after the solid-phase extraction ranged from 70 to 80% for a wide range of urinary 8OHdG levels. Using 1 ml of urine, the limit of quantification was >2.5 nM (2.5 pmol/ml) and the calibration curve was linear in the range 2.5–200 nM. This method was applied to measure 8OHdG in urine samples from 12 healthy subjects. The intra- and inter-day variations were <9%. Urinary 8OHdG levels in spot urine samples from four healthy subjects were also measured for 1 week and, again, the variation was small. The presence of H2O2 in urine did not cause artifactual formation of 8OHdG. Since this assay is simple, rapid, sensitive and reproducible, it seems suitable to be used as a routine methodology for the measurement of urinary excretion of 8OHdG in large population studies.

PATTERNS OF GROWTH IN HEIGHT AND WEIGHT FROM BIRTH TO EIGHTEEN YEARS OF AGE

PEDIATRICS ◽  
1959 ◽  
Vol 24 (5) ◽  
pp. 904-921
Author(s):  
Robert B. Reed ◽  
Harold C. Stuart
Keyword(s):  
Growth Curves ◽  
Growth Patterns ◽  
Individual Growth ◽  
Growth Spurt ◽  
Adolescent Growth Spurt ◽  
Wide Range ◽  
Basic Facts ◽  
The Individual ◽  
Rates Of Growth ◽  
Mature Size

In this report is displayed the range of variation observed in the growth curves of height and weight in a series of 134 children observed from birth to 18 years. For purposes of simplification the individuals have been classified on the basis of their rates of growth during three successive 6-year intervals. Even in terms of this crude classification several basic facts about individual growth patterns of height and weight are apparent. The wide range of differences between individuals applies not only to facts about size at specific ages but also to the pattern of change followed from age period to age period. The rate of growth during early childhood, i.e. before 6 years of age, is associated with, but not specifically predictive of, size at maturity and timing of the adolescent growth spurt. Individuals with rapid growth before 6 years of age tend to have large mature size and early adolescent growth spurt. It will be the objective of future reports from this research project to determine the manner in which the individual differences in growth demonstrated and classified here are related to aspects of physical development, to environmental influences such as dietary intake and to the level of health of the child.

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