14th Acidic Friday 

14th Acidic Friday 
Date: 21.10.2022
Venue: Zoom
Location: Online

Open discussion platform of the COST action EuroMicropH. This discussion series is intended to stimulate an exchange on the different aspects of how microorganisms react to low pH conditions and why people are interested to investigate this subject. 

Please register here for the upcoming meeting. To access the session, please follow the zoom link below.

21.10.2022 16:00 CEST

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Meeting-ID: 966 8254 7717
Password: 00etXANe


16:00 Welcome

16:05 Ivo van den Hurk, TU Wien, Austria

Microbial upgrading of one-carbon compounds for chemical production

16:30 Danai Etter, University of Zurich, Switzerland

Mild Lactic Acid Stress Causes Strain-Dependent Reduction in SEC Protein Levels

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Microbial upgrading of one-carbon compounds for chemical production

Ivo van den Hurk

The current fossil fuel-based economy is arguably unsustainable in the long term, which has led to an increased interest towards renewable, CO2-neutral resources such as biomass and cellulosic materials to generate the necessary energy and materials. CO2, CO and H2 derived from plant biomass gasification and industrial gaseous waste streams (e.g. steel milling process) are potential alternative carbon and energy sources for value-added chemical and fuel production. Acetogenic bacterium Thermoanaerobacter kivui is a promising microbial catalyst since it accommodates CO2 fixation to value-added bioproducts. Lactic acid (LA) is an appealing bioproduct for its various applications in the pharmaceutical, cosmetic and food industry.

Mild Lactic Acid Stress Causes Strain-Dependent Reduction in SEC Protein Levels

Danai Etter

Staphylococcal enterotoxin C (SEC) is a major cause of staphylococcal food poisoning in humans and plays a role in bovine mastitis. Staphylococcus aureus (S. aureus) benefits from a competitive growth advantage under stress conditions encountered in foods such as a low pH. Therefore, understanding the role of stressors such as lactic acid on SEC production is of pivotal relevance to food safety. However, stress-dependent cues and their effects on enterotoxin expression are still poorly understood. In this study, we used human and animal strains harboring different SEC variants in order to evaluate the influence of mild lactic acid stress (pH 6.0) on SEC expression both on transcriptional and translational level. Although only a modest decrease in secmRNA levels was observed under lactic acid stress, protein levels showed a significant decrease in SEC levels for some strains. These findings indicate that post-transcriptional modifications can act in SEC expression under lactic acid stress.

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