Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.
- MeSH
- Acetone MeSH
- Butanols MeSH
- Clostridium beijerinckii * MeSH
- Clostridium MeSH
- Ethanol MeSH
- Fermentation MeSH
- Publication type
- Journal Article MeSH
Alkohol patří mezi nejvýznamnější determinanty zdraví, a současně jeho konzumace v ČR je jedna z nejvyšších na světě. Měření konzumace alkoholu v epidemiologických studiích rizikových faktorů neinfekčních onemocnění je proto velmi žádoucí. V Brně aktuálně běží velký kardiovaskulární projekt organizovaný Mezinárodním centrem klinického výzkumu ICRC ve spolupráci s Masarykovou univerzitou. Jeho součástí je rovněž hodnocení konzumace alkoholu a jejího efektu, ve vztahu ke všem podstatným kardiovaskulárním klinickým parametrům, ale i ostatním faktorů životního stylu, jako je výživa, pohybová aktivita a kouření. Pro tyto účely byl vytvořen nový dotazníkový nástroj a v článku popisujeme příslušná východiska ve formě přehledu existujících přístupů k měření konzumace alkoholu, velmi detailně otázku obsahu alkoholu v různých nápojích, a podrobně vlastní alkoholový dotazník. Ten má pouze 7 položek, a je tedy velmi kompaktní, přitom pokrývá celkově poměrně dlouhou časovou periodu, rozdělenou na sekce dotazníku zabývající se posledním rokem, měsícem a týdnem. Týdenní recall je specifický nápojově i dle jednotlivých dnů v týdnu, kvantifikace množství je řešena převodem na alkoholové jednotky. Sekce zaměřené na delší periody by měly identifikovat nepravidelné nárazové pití, a určit celkový vzorec – charakter konzumace. V době vzniku článku již bylo tímto dotazníkem (a celým komplexem klinických i anamnestických vyšetření) otestováno více než 1000 osob náhodně vybraného vzorku brněnských obyvatel, kdy cílem je vyšetřit minimálně 2000 osob. Diskutovány jsou silné a slabé stránky různých přístupů. Náš dotazník se pro plánovaný účel osvědčil, a můžeme je doporučit i pro jiné epidemiologické studie.
Alcohol is one of the most important determinants of health, while its consumption in the Czech Republic is one of the highest in the world. Measuring alcohol consumption in epidemiological studies of risk factors of non-communicable diseases is therefore highly desirable. In Brno, an extensive cardiovascular project, organized by the International Centre for Clinical Research (ICRC) in cooperation with Masaryk University, is currently in progress. It includes an assessment of alcohol consumption and its effects in relation to all significant cardiovascular clinical parameters, but also in relation to other lifestyle factors such as nutrition, physical activity and smoking. A new questionnaire tool was created for this purpose; the article describes the appropriate starting point in the form of an overview of existing approaches to measuring alcohol consumption and detailed breakdown of issues regarding the content of alcohol in different beverages and alcohol units, and the alcohol questionnaire as such. The questionnaire contains 7 items only and is very compact despite its coverage of a relatively long time-period, divided into sections covering the preceding year, month and weekly timespans. Weekly recall is beverage specific and even specific by weekdays; quantification of ingested volume is described by means of alcohol units. The section focusing on longer time-periods should identify irregular binge drinking, and determine the overall pattern of consumption. At the time of writing this article, a sample of over 1,000 randomly selected inhabitants of Brno was examined with this alcohol questionnaire and by a complex of lifestyle and clinical examinations, with the objective of involving a total of at least 2,000 subjects. Strengths and weaknesses of different approaches to the measurement of alcohol consumption are discussed. Our questionnaire fulfilled the intended purpose, and we can recommend it for use in other epidemiological studies.
- Keywords
- projekt Kardiovize 2030,
- MeSH
- Alcoholic Beverages MeSH
- Time Factors MeSH
- Epidemiologic Studies MeSH
- Ethanol analysis MeSH
- Cardiovascular Diseases prevention & control MeSH
- Humans MeSH
- Alcohol Drinking * MeSH
- Beer MeSH
- Surveys and Questionnaires * standards MeSH
- Mental Recall MeSH
- Wine MeSH
- Research Design MeSH
- Life Style MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
The increase in ammonia and ethanol in the exhaled breath stream following mouthwashes by aqueous solutions of urea and sugar (sucrose), respectively, has been investigated by analysing exhaled breath in real time using selected ion flow tube mass spectrometry, SIFT-MS. It is shown that the measured levels of these compounds in the stream of exhaled breath can be much greater than the endogenous levels originating at the alveolar boundary. Thus, it is concluded that without careful preparation, mouth production of these compounds, and other compounds as yet unidentified, can seriously compromise the quantification of truly endogenous trace compounds present in blood and in the alveolar breath, as required for clinical diagnosis, and can probably introduce additional compounds into the breath stream that could seriously mislead breath analysis. The concentrations of both the urea and sucrose solutions used to enhance the ammonia and ethanol levels were larger than normally present in food and drinks and so in most situations such severe enhancements will not occur.
