Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
Rapid Acid Treatment Of Escherichia Coli: Transcriptomic Response And Recovery, Brian Jones, Geetha Kannan, Jessica C. Wilks, Devon M. Fitzgerald, Sandra S. Bondurant, Joan L. Slonczewski
Rapid Acid Treatment Of Escherichia Coli: Transcriptomic Response And Recovery, Brian Jones, Geetha Kannan, Jessica C. Wilks, Devon M. Fitzgerald, Sandra S. Bondurant, Joan L. Slonczewski
Brian Jones
Background: Many E. coli genes show pH-dependent expression during logarithmic growth in acid (pH 5–6) or in base (pH 8–9). The effect of rapid pH change, however, has rarely been tested. Rapid acid treatment could distinguish between genes responding to external pH, and genes responding to cytoplasmic acidification, which occurs transiently following rapid external acidification. It could reveal previously unknown acid-stress genes whose effects are transient, as well as show which acid-stress genes have a delayed response. Results: Microarray hybridization was employed to observe the global gene expression of E. coli K-12 W3110 following rapid acidification of the external medium, …
Tree And Forest Weights And Their Application To Nonuniform Random Graphs, Brian Jones, Boris G. Pittel, Joseph S. Verducci
Tree And Forest Weights And Their Application To Nonuniform Random Graphs, Brian Jones, Boris G. Pittel, Joseph S. Verducci
Brian Jones
For a complete graph Kn on n vertices with weighted edges, define the weight of a spanning tree (more generally, spanning forest) as the product of edge weights involved. Define the tree weight (forest weight) of Kn as the total weight of all spanning trees (forests). The uniform edge weight distribution is shown to maximize the tree weight, and an explicit bound on the tree weight is formulated in terms of the overall variance of edge weights as well as the variance of the sum of edge weights over nodes. An application to sparse random graphs leads to a bound …
Oxygen Limitation Modulates Ph Regulation Of Catabolism And Hydrogenases, Multidrug Transporters, And Envelope Composition In Escherichia Coli K-12, Brian Jones, Everett T. Hayes, Jessica C. Wilks, Piero Sanfilippo, Elizabeth Yohannes, Daniel P. Tate, Michael D. Radmacher, Joan L. Slonczewski, Sandra S. Bondurant
Oxygen Limitation Modulates Ph Regulation Of Catabolism And Hydrogenases, Multidrug Transporters, And Envelope Composition In Escherichia Coli K-12, Brian Jones, Everett T. Hayes, Jessica C. Wilks, Piero Sanfilippo, Elizabeth Yohannes, Daniel P. Tate, Michael D. Radmacher, Joan L. Slonczewski, Sandra S. Bondurant
Brian Jones
Background: In Escherichia coli, pH regulates genes for amino-acid and sugar catabolism, electron transport, oxidative stress, periplasmic and envelope proteins. Many pH-dependent genes are co-regulated by anaerobiosis, but the overall intersection of pH stress and oxygen limitation has not been investigated. Results: The pH dependence of gene expression was analyzed in oxygen-limited cultures of E. coli K-12 strain W3110. E. coli K-12 strain W3110 was cultured in closed tubes containing LBK broth buffered at pH 5.7, pH 7.0, and pH 8.5. Affymetrix array hybridization revealed pH-dependent expression of 1,384 genes and 610 intergenic regions. A core group of 251 genes …