Cellular Response ofEscherichia colito Photocatalysis: Flagellar Assembly Variation and Beyond

Abstract

Bacterial cells can be inactivated by external reactive oxygen species (ROS) produced by semiconductor photocatalysis. However, little is known about cellular responses to photocatalysis. For a better understanding of this issue, one strain of Escherichia coli (E. coli, hereafter named as MT), which has an increased ability to metabolize carbon sources, was screened out from the wild-type (WT) E. coli K12 by repeated exposure to photocatalysis with palladium oxide modified nitrogen-doped titanium dioxide. In this study, transcriptome sequencing of the WT and MT strains that were exposed or unexposed to photocatalysis were carried out. Cellular responses to photocatalysis were inferred from the functions of genes whose transcripts were either increased or decreased. Upregulation of expression of bacterial flagellar assembly genes used for chemotaxis was detected in cells exposed to semilethal photocatalytic conditions of the WT E. coli. Increased capability to degrade superoxide radicals and decreased bacterial flagellar assembly and chemotaxis were observed in MT E. coli compared to WT cells. We conclude that the differences in motility and intracellular ROS between MT and WT are directly related to survivability of E. coli during exposure to photodisinfection.

Layered Double Hydroxide Modified Bone Cement Promoting Osseointegration via Multiple Osteogenic Signal Pathways

“…Transcriptome sequencing was further performed to reveal the mechanism of osteogenic differentiation induced by PMMA&LDH in comparison with PMMA, − and the process of database construction and bioinformatics analysis of transcriptome sequencing were shown in Figure S11. The total number of differentially expressed genes ( P value < 0.05 and |log 2 Fold Change| > 1) is 739, which includes 367 upregulated genes and 372 downregulated genes (Figure a).…”

Tuning Microbial Activity via Programmatic Alteration of Cell/Substrate Interfaces

“…Column 2 comments on the type of the surface that was created. For example, the materials are commonly used in the form of thin films [98,99,[129][130][131][132][133]100,103,104,[124][125][126][127][128] nanopatterned fiber, [134][135][136] nanopowder, [137,138] or nanorod [139,140] coatings on various test substrates (i.e., glass, steel, and specific polymers).…”

“…[94,147,148] Column 3 summarizes the types of microorganisms deposited on the substrates. Furthermore, additional factors like external stimuli (i.e., UV [92,93,[123][124][125]128,129,132,[137][138][139][140]95,141,144,146,98,100,[102][103][104]109,110] or visible light [130,131,134,149] ) may be introduced for the purpose of cleaning, changing material's characteristics or boosting reactions happening within the biointerfaces. Column 4 summarizes applications and use of such external stimuli.…”

“…[98,[109][110][111]124,150,151] The most common inorganic materials used in biointerfacial structures are metal oxides such as ZnO, [95,98,139,140,99,101,[124][125][126][127]133,134] TiO 2 . [100,102,[136][137][138][141][142][143][144][145][146]103,104,[128][129][130][131][132]135] These materials have been demonstrated as effective antibacterial coatings. For example, as it was shown in studies of Park et al, [125] or Sunada and coworkers, [129] thin films of ZnO or TiO 2 express antimicrobial behavior.…”

“…In some studies, external stimuli have been used to directly influence the biofilm on the interface, thus exploring the reaction of microorganisms placed on a substrate under changing external conditions. For example, a set of studies uses low or high temperature, [102,146] visible light, [131] metal salts (like Ga(NO 3 ) 3 and FeCl 3 ), [182,189] or chemicals and surfactants (glutaraldehyde, ortho-phthalaldehyde, cetyltrimethylammonium bromide, benzalkonium chloride, sodium dodecyl sulfate, sodium hydroxide, sodium hypochlorite) [186] dissolved in the media, as factors activating processes of biofilm morphology and growth rate alterations. The goal of these surface treatments is to develop new ways to control cells and specifically microbial behavior.…”