Microgravity as a Novel Environmental Signal Affecting
            <i>Salmonella enterica</i>
            Serovar Typhimurium Virulence

Nickerson, Cheryl A.; Ott, C. Mark; Mister, Sarah J.; Morrow, Brian J.; Burns-Keliher, Lisa; Pierson, Duane L.

doi:10.1128/iai.68.6.3147-3152.2000

Cited by 213 publications

(260 citation statements)

References 30 publications

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“…Studies were performed with wild-type S. enterica serovar Typhimurium 3339 (12) (an animal-passaged isolate of SL1344) and an isogenic fur mutant derivative 4659 (kindly provided by Roy Curtiss III, Washington University, St. Louis, MO). All strains were grown in Lennox broth (13) in the HARV (Synthecon, Houston) at 37°C under both 1 ϫ g and LSMMG by using a 50-ml culture volume and 25 rpm rotational speed, as described previously (9). The cultivation conditions of LSMMG and 1 ϫ g were achieved by changing the physical orientation of the HARV as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Bacteria grown under LSMMG and 1 ϫ g were subjected to acid stress of pH 3.5, as described previously (9). The average percent survival of three independent trials was calculated as the ratio of colony-forming units (cfu) at each time point to cfu at time 0.…”

Section: Methodsmentioning

confidence: 99%

“…Salmonella grown under LSMMG, as compared with identical growth conditions at normal gravity (1 ϫ g), displayed a decreased LD 50 , shortened host time-to-death, and increased colonization of liver and spleen in the murine model of infection. LSMMG-grown Salmonella also displayed increased resistance to environmental stresses (acid, thermal, and osmotic), increased ability to survive within macrophages, and alterations in protein expression levels (9,10). This global change in phenotype and protein expression by Salmonella in response to LSMMG indicates the existence of a regulatory network we term the ''LSMMG regulon.''…”

mentioning

confidence: 99%

“…The latter environment is relevant to that encountered by numerous bacterial pathogens during the natural course of infection of the gastrointestinal, respiratory, and urogenital tracts. In addition, because several cellular responses observed under low-shear optimized suspension culture mimic those observed during cell culture in space, this culture environment is also used for ground-based studies of the effects of modeled microgravity on both eukaryotic and prokaryotic cellular physiology (1,9). We have previously shown that growth conditions of low-shear modeled microgravity (LSMMG) increase the virulence potential of the invasive enteric pathogen Salmonella enterica serovar Typhimurium (9).…”

mentioning

confidence: 99%

“…In addition, because several cellular responses observed under low-shear optimized suspension culture mimic those observed during cell culture in space, this culture environment is also used for ground-based studies of the effects of modeled microgravity on both eukaryotic and prokaryotic cellular physiology (1,9). We have previously shown that growth conditions of low-shear modeled microgravity (LSMMG) increase the virulence potential of the invasive enteric pathogen Salmonella enterica serovar Typhimurium (9). Salmonella grown under LSMMG, as compared with identical growth conditions at normal gravity (1 ϫ g), displayed a decreased LD 50 , shortened host time-to-death, and increased colonization of liver and spleen in the murine model of infection.…”

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confidence: 99%

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Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon

Wilson

Ramamurthy

Porwollik

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The low-shear environment of optimized rotation suspension culture allows both eukaryotic and prokaryotic cells to assume physiologically relevant phenotypes that have led to significant advances in fundamental investigations of medical and biological importance. This culture environment has also been used to model microgravity for ground-based studies regarding the impact of space flight on eukaryotic and prokaryotic physiology. We have previously demonstrated that low-shear modeled microgravity (LSMMG) under optimized rotation suspension culture is a novel environmental signal that regulates the virulence, stress resistance, and protein expression levels of Salmonella enterica serovar Typhimurium. However, the mechanisms used by the cells of any species, including Salmonella, to sense and respond to LSMMG and identities of the genes involved are unknown. In this study, we used DNA microarrays to elucidate the global transcriptional response of Salmonella to LSMMG. When compared with identical growth conditions under normal gravity (1 ؋ g), LSMMG differentially regulated the expression of 163 genes distributed throughout the chromosome, representing functionally diverse groups including transcriptional regulators, virulence factors, lipopolysaccharide biosynthetic enzymes, iron-utilization enzymes, and proteins of unknown function. Many of the LSMMG-regulated genes were organized in clusters or operons. The microarray results were further validated by RT-PCR and phenotypic analyses, and they indicate that the ferric uptake regulator is involved in the LSMMG response. The results provide important insight about the Salmonella LSMMG response and could provide clues for the functioning of known Salmonella virulence systems or the identification of uncharacterized bacterial virulence strategies.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon

Wilson

Ramamurthy

Porwollik

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

155

191

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Increased biofilm formation ability in Klebsiella pneumoniae after short‐term exposure to a simulated microgravity environment

et al. 2016

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Biofilm formation is closely related to the pathogenetic processes of Klebsiella pneumoniae, which frequently causes infections in immunocompromised individuals. The immune system of astronauts is compromised in spaceflight. Accordingly, K. pneumoniae, which used to be isolated from orbiting spacecraft and astronauts, poses potential threats to the health of astronauts and mission security. Microgravity is a key environmental cue during spaceflight. Therefore, determining its effects on bacterial biofilm formation is necessary. In this study, K. pneumoniae ATCC BAA‐1705 was exposed to a simulated microgravity (SMG) environment. K. pneumoniae grown under SMG formed thicker biofilms compared with those under normal gravity (NG) control after 2 weeks of subculture. Two indicative dyes (i.e., Congo red and calcofluor) specifically binding to cellulose fibers and/or fimbriae were utilized to reconfirm the enhanced biofilm formation ability of K. pneumoniae grown under SMG. Further analysis showed that the biofilms formed by SMG‐treated K. pneumoniae were susceptible to cellulase digestion. Yeast cells mannose‐resistant agglutination by K. pneumoniae type 3 fimbriae was more obvious in the SMG group, which suggests that cellulose production and type 3 fimbriae expression in K. pneumoniae were both enhanced under the SMG condition. Transcriptomic analysis showed that 171 genes belonging to 15 functional categories were dysregulated in this organism exposed to the SMG conditions compared with those in the NG group, where the genes responsible for the type 3 fimbriae (mrkABCDF) and its regulator (mrkH) were upregulated.

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Differential proteomic analysis using isotope‐coded protein‐labeling strategies: Comparison, improvements and application to simulated microgravity effect on Cupriavidus metallidurans CH34

et al. 2010

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Among differential proteomic methods based on stable isotopic labeling, isotope-coded protein labeling (ICPL) is a recent non-isobaric technique devised to label primary amines found in proteins. ICPL overcomes some of the disadvantages found in other chemical-labeling techniques, such as iTRAQ or ICAT. However, previous analyses revealed that more than 30% of the proteins identified in regular ICPL generally remain unquantified. In this study, we describe a modified version of ICPL, named Post-digest ICPL, that makes it possible to label and thus to quantify all the peptides in a sample (bottom-up approach). Optimization and validation of this Post-digest ICPL approach were performed using a standard protein mixture and complex protein samples. Using this strategy, the number of proteins that were identified and quantified was greatly increased in comparison with regular ICPL and cICAT approaches. The pros and cons of this improvement are discussed. This complementary approach to traditional ICPL was applied to the analysis of modification of protein abundances in the model bacterium Cupriavidus metallidurans CH34 after cultivation under simulated microgravity. In this context, two different systems - a 2-D clinorotation and 3-D random positioning device - were used and the results were compared and discussed.

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Microgravity as a Novel Environmental Signal Affecting Salmonella enterica Serovar Typhimurium Virulence

Cited by 213 publications

References 30 publications

Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon

Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon

Increased biofilm formation ability in Klebsiella pneumoniae after short‐term exposure to a simulated microgravity environment

Differential proteomic analysis using isotope‐coded protein‐labeling strategies: Comparison, improvements and application to simulated microgravity effect on Cupriavidus metallidurans CH34

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