Matches in DBpedia 2016-04 for { ?s ?p "Diauxie is a Greek word coined by Jacques Monod to mean two growth phases. The word is used in English in cell biology to describe the growth phases of a microorganism in batch culture as it metabolizes a mixture of two sugars. Rather than metabolizing the two available sugars simultaneously, microbial cells commonly consume them in a sequential pattern, resulting in two separate growth phases. During the first phase, cells preferentially metabolize the sugar on which it can grow faster (often glucose but not always). Only after the first sugar has been exhausted do the cells switch to the second. At the time of the \"diauxic shift\", there is often a lag period during which cells produce the enzymes needed to metabolize the second sugar. Jacques Monod discovered diauxic growth in 1941 during his experiments with Escherichia coli and Bacillus subtilis. While growing these bacteria on various combination of sugars during his doctoral thesis research, Monod observed that often two distinct growth phases are clearly visible in batch culture, as seen in Figure 1. He later put aside his work on diauxic growth and focused on the lac operon model of gene expression, which led to a Nobel prize.Diauxie occurs because organisms use operons or multiple sets of genes to control differently the expression of enzymes needed to metabolize the different nutrients or sugars they encounter. If an organism allocates its energy and other resources (e.g. amino acids) to synthesize enzymes needed to metabolize a sugar that can only support a slower growth rate and not use all or most of its available resources to synthesize the enzymes that metabolize a different sugar providing a faster growth rate, such an organism will be at a reproductive disadvantage compared to those that choose to grow on the faster growth supporting sugar. Through evolution, organisms have developed the ability to regulate their genetic control mechanisms so as to only express those genes resulting in the fastest growth rate. For example, when grown in the presence of both glucose and maltose, Lactococcus lactis will produce enzymes to metabolize glucose first, altering its gene expression to use maltose only after the supply of glucose has been exhausted. In the case of the baker's or brewer's yeast Saccharomyces cerevisiae growing on glucose with plenty of aeration, the diauxic growth pattern is commonly observed in batch culture. During the first growth phase, when there is plenty of glucose and oxygen available, the yeast cells prefer glucose fermentation to aerobic respiration even though aerobic respiration is the more efficient pathway to grow on glucose. Contrary to the more commonly invoked Pasteur effect, this phenomenon of preferring the faster growth supporting fermentation is closer to the Warburg effect observed in faster growing tumors. The intracellular genetic regulatory mechanisms have evolved to enforce this choice, as fermentation provides a faster growth rate for the yeast cells than the aerobic respiration of glucose. After glucose is depleted, the fermentative product ethanol is oxidised in a noticeably slower second growth phase, if oxygen is available."@en }
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- Diauxie abstract "Diauxie is a Greek word coined by Jacques Monod to mean two growth phases. The word is used in English in cell biology to describe the growth phases of a microorganism in batch culture as it metabolizes a mixture of two sugars. Rather than metabolizing the two available sugars simultaneously, microbial cells commonly consume them in a sequential pattern, resulting in two separate growth phases. During the first phase, cells preferentially metabolize the sugar on which it can grow faster (often glucose but not always). Only after the first sugar has been exhausted do the cells switch to the second. At the time of the \"diauxic shift\", there is often a lag period during which cells produce the enzymes needed to metabolize the second sugar. Jacques Monod discovered diauxic growth in 1941 during his experiments with Escherichia coli and Bacillus subtilis. While growing these bacteria on various combination of sugars during his doctoral thesis research, Monod observed that often two distinct growth phases are clearly visible in batch culture, as seen in Figure 1. He later put aside his work on diauxic growth and focused on the lac operon model of gene expression, which led to a Nobel prize.Diauxie occurs because organisms use operons or multiple sets of genes to control differently the expression of enzymes needed to metabolize the different nutrients or sugars they encounter. If an organism allocates its energy and other resources (e.g. amino acids) to synthesize enzymes needed to metabolize a sugar that can only support a slower growth rate and not use all or most of its available resources to synthesize the enzymes that metabolize a different sugar providing a faster growth rate, such an organism will be at a reproductive disadvantage compared to those that choose to grow on the faster growth supporting sugar. Through evolution, organisms have developed the ability to regulate their genetic control mechanisms so as to only express those genes resulting in the fastest growth rate. For example, when grown in the presence of both glucose and maltose, Lactococcus lactis will produce enzymes to metabolize glucose first, altering its gene expression to use maltose only after the supply of glucose has been exhausted. In the case of the baker's or brewer's yeast Saccharomyces cerevisiae growing on glucose with plenty of aeration, the diauxic growth pattern is commonly observed in batch culture. During the first growth phase, when there is plenty of glucose and oxygen available, the yeast cells prefer glucose fermentation to aerobic respiration even though aerobic respiration is the more efficient pathway to grow on glucose. Contrary to the more commonly invoked Pasteur effect, this phenomenon of preferring the faster growth supporting fermentation is closer to the Warburg effect observed in faster growing tumors. The intracellular genetic regulatory mechanisms have evolved to enforce this choice, as fermentation provides a faster growth rate for the yeast cells than the aerobic respiration of glucose. After glucose is depleted, the fermentative product ethanol is oxidised in a noticeably slower second growth phase, if oxygen is available.".