Global gene regulation in Yersinia enterocolitica: effect of FliA on the expression levels of flagellar and plasmid-encoded virulence genes

DNA adenine methyltransferase (Dam) plays an important role in physiological processes of Gram-negative bacteria such as mismatch repair and replication. In addition, Dam regulates the expression of virulence genes in various species. The authors cloned the dam gene of Yersinia enterocolitica and showed that Dam is essential for viability. Dam overproduction in Y. enterocolitica resulted in an increased frequency of spontaneous mutation and decreased resistance to 2-aminopurine; however, these effects were only marginal compared to the effect of overproduction of Escherichia coli-derived Dam in Y. enterocolitica, implying different roles or activities of Dam in mismatch repair of the two species. These differences in Dam function are not the cause for the essentiality of Dam in Y. enterocolitica, as Dam of E. coli can complement a dam defect in Y. enterocolitica. Instead, Dam seems to interfere with expression of essential genes. Furthermore, Dam mediates virulence of Y. enterocolitica. Dam overproduction results in increased tissue culture invasion of Y. enterocolitica, while the expression of specifically in vivo-expressed genes is not altered.

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Detection of pathogenic Yersinia enterocolitica serotype O:3 by biochemical, serological, and PCR methods

Czech Journal of Food Sciences ◽

10.17221/686-cjfs ◽

2008 ◽

Vol 25 (No. 4) ◽

pp. 214-220 ◽

Cited By ~ 3

Author(s):

J. Simonová ◽

M. Vázlerová ◽

I. Steinhauserová

Keyword(s):

Czech Republic ◽

Yersinia Enterocolitica ◽

Virulence Genes ◽

Optimum Time ◽

The Czech Republic ◽

Specific Identification ◽

Time Consumption ◽

Serotype O

In this study, the pathogenic Y. enterocolitica of serotype O:3 was monitored. The serotype is widely spread in Europe and has been linked to human yersiniosis. For the detection of pathogenic strains were used biochemical and serological methods as well as PCR methods based on the identification of virulence genes (ail, rfbC, ystA, yadA, virF). The occurrence of Y. enterocolitica O:3 strains was monitored in slaughter animals from a number of farms in the Czech Republic. A total of 3748 samples were collected coming from pigs (1388), cattle (633), poultry (902), and slaughter facilities (825). Fifty-two Y. enterocolitica O:3 isolates were identified by biochemical and serologic methods, and 53 Y. enterocolitica O:3 isolates were identified by PCR methods (46 isolates from pigs, 2 isolates from poultry, 3 isolates from cattle, and 2 isolates from a poultry slaughtering facility). All isolates of Y. enterocolitica O:3 carried genes ail and rfbC, 83% isolates carried gene ystA, 79% isolates carried gene yadA and 49% isolates carried gene virF. The use of PCR methods based on the identification of ail and rfbC genes provides for a sufficiently specific identification of pathogenic Y. enterocolitica O:3 strains with optimum time consumption compared to biochemical and serological methods. It is not recommendable to use other PCR methods (detection of the ystA, yadA, and virF genes) for the detection of pathogenic Y. enterocolitica strains because those methods are not very specific for the determination of pathogenicity.

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Computational modelling unravels the precise clockwork of cyanobacteria

Interface Focus ◽

10.1098/rsfs.2018.0038 ◽

2018 ◽

Vol 8 (6) ◽

pp. 20180038 ◽

Cited By ~ 4

Author(s):

Nicolas M. Schmelling ◽

Ilka M. Axmann

Keyword(s):

Gene Expression ◽

Gene Regulation ◽

Circadian Clock ◽

Environmental Changes ◽

Regulation Of Gene Expression ◽

Computational Modelling ◽

Circadian Clocks ◽

Fitness Advantage ◽

Fundamental Part ◽

Global Gene Regulation

Precisely timing the regulation of gene expression by anticipating recurring environmental changes is a fundamental part of global gene regulation. Circadian clocks are one form of this regulation, which is found in both eukaryotes and prokaryotes, providing a fitness advantage for these organisms. Whereas many different eukaryotic groups harbour circadian clocks, cyanobacteria are the only known oxygenic phototrophic prokaryotes to regulate large parts of their genes in a circadian fashion. A decade of intensive research on the mechanisms and functionality using computational and mathematical approaches in addition to the detailed biochemical and biophysical understanding make this the best understood circadian clock. Here, we summarize the findings and insights into various parts of the cyanobacterial circadian clock made by mathematical modelling. These findings have implications for eukaryotic circadian research as well as synthetic biology harnessing the power and efficiency of global gene regulation.

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Antibacterial Mechanism of 405-Nanometer Light-Emitting Diode against Salmonella at Refrigeration Temperature

Applied and Environmental Microbiology ◽

10.1128/aem.02582-16 ◽

2016 ◽

Vol 83 (5) ◽

Cited By ~ 25

Author(s):

Min-Jeong Kim ◽

Hyun-Gyun Yuk

Keyword(s):

Gene Expression ◽

Gene Regulation ◽

Light Emitting Diode ◽

Dna Oxidation ◽

Uptake System ◽

Antibacterial Mechanism ◽

Content Type ◽

Light Emitting ◽

Expression Levels ◽

Gene Expression Levels

ABSTRACT The aim of this study was to elucidate the antibacterial mechanism of 405 ± 5-nm light-emitting diode (LED) illumination against Salmonella at 4°C in phosphate-buffered saline (PBS) by determining endogenous coproporphyrin content, DNA oxidation, damage to membrane function, and morphological change. Gene expression levels, including of oxyR, recA, rpoS, sodA, and soxR, were also examined to understand the response of Salmonella to LED illumination. The results showed that Salmonella strains responded differently to LED illumination, revealing that S. enterica serovar Enteritidis (ATCC 13076) and S. enterica subsp. enterica serovar Saintpaul (ATCC 9712) were more susceptible and resistant, respectively, than the 16 other strains tested. There was no difference in the amounts of endogenous coproporphyrin in the two strains. Compared with that in nonilluminated cells, the DNA oxidation levels in illuminated cells increased. In illuminated cells, we observed a loss of efflux pump activity, damage to the glucose uptake system, and changes in membrane potential and integrity. Transmission electron microscopy revealed a disorganization of chromosomes and ribosomes due to LED illumination. The levels of the five genes measured in the nonilluminated and illuminated S. Saintpaul cells were upregulated in PBS at a set temperature of 4°C, indicating that increased gene expression levels might be due to a temperature shift and nutrient deficiency rather than to LED illumination. In contrast, only oxyR in S. Enteritidis cells was upregulated. Thus, different sensitivities of the two strains to LED illumination were attributed to differences in gene regulation. IMPORTANCE Bacterial inactivation using visible light has recently received attention as a safe and environmentally friendly technology, in contrast with UV light, which has detrimental effects on human health and the environment. This study was designed to understand how 405 ± 5-nm light-emitting diode (LED) illumination kills Salmonella strains at refrigeration temperature. The data clearly demonstrated that the effectiveness of LED illumination on Salmonella strains depended highly on the serotype and strain. Our findings also revealed that its antibacterial mechanism was mainly attributed to DNA oxidation and a loss of membrane functions rather than membrane lipid peroxidation, which has been proposed by other researchers who studied the antibacterial effect of LED illumination by adding exogenous photosensitizers, such as chlorophyllin and hypericin. Therefore, this study suggests that the detailed antibacterial mechanisms of 405-nm LED illumination without additional photosensitizers may differ from that by exogenous photosensitizers. Furthermore, a change in stress-related gene regulation may alter the susceptibility of Salmonella cells to LED illumination at refrigeration temperature. Thus, our study provides new insights into the antibacterial mechanism of 405 ± 5-nm LED illumination on Salmonella cells.

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