Project description:In large-scale production processes, metabolic control is typically achieved by limited supply of essential nutrients like ammonia. With increasing bioreactor dimensions, microbial producers such as Escherichia coli are exposed to changing substrate availabilities due to limited mixing. In turn, cells sense and respond to these dynamic conditions leading to frequent activation of their regulatory programs which result in production yield losses. This study is focused on transcriptional changes due to fluctuating ammonia supply, while sampling a continuously running two-compartment bioreactor system comprising a stirred tank reactor (STR) and a plug flow reactor (PFR). A previously created mutant E.coli SR was used to limit the reaction to environmntal influences via knock-out of stringent response. E. coli WT revealed highly diverging short-term transcriptional responses in ammonia fluctuation compared E. coli SR.
Project description:In large-scale production processes, metabolic control is typically achieved by limited supply of essential nutrients like glucose or ammonia. With increasing bioreactor dimensions, microbial producers such as Escherichia coli are exposed to changing substrate availabilities due to limited mixing. In turn, cells sense and respond to these dynamic conditions leading to frequent activation of their regulatory programs. Previously, we characterized short- and long-term strategies of cells to adapt to glucose fluctuations. Here, we focused on fluctuating ammonia supply, while studying a continuously running two-compartment bioreactor system comprising a stirred tank reactor (STR) and a plug flow reactor (PFR). Genes were repeatedly switched on/off when E. coli returned to the STR. Moreover, E. coli revealed highly diverging long-term transcriptional responses in ammonia compared to glucose fluctuations. The identification of target genes may help to create robust cells and processes for large-scale application.
Project description:The purpose of this study is to determine whether the presence of pathogenic Escherichia coli in colon is associated with psychiatric disorders.
Project description:Despite the characterization of many aetiologic genetic changes. The specific causative factors in the development of sporadic colorectal cancer remain unclear. This study was performed to detect the possible role of Enteropathogenic Escherichia coli (EPEC) in developing colorectal carcinoma.
Project description:Transcription profile of Escherichia coli cells in biofilms under static batch culture was compared to that of E. coli cells in planktonic cultures. Both E. coli biofilm and planktonic cultures were cultivated for 18 h in 10% Luria-Bertani broth at room temperature (20 degree Celsius). Biofilms were grown in static batch culture in petri dishes. Both planktonic culture and biofilms were homogenized and run through a separated protocol.
Project description:Long-term experiment (150 days) of Escherichia coli MC1000 with daily transfers into fresh LB medium and under three different oxygen regimes.
Project description:Inorganic polyphosphate (polyP) is synthesized by bacteria in response to various stresses, but the mechanism of its regulation is unknown. Mutants of Escherichia coli lacking the RNA polymerase-binding transcription factor dksA are defective in polyP synthesis after a nutrient limitation stress, and this defect is reversed in a dksA greA mutant. In this work, we used RNA sequencing to compare transcription in wild-type, dksA, and dksA greA strains of E. coli before and after nutrient limitation, to identify genes whose expression pattern correlates with ability to synthesize polyP.
