Novel iron‐regulated and Fur‐regulated small regulatory RNAs in <i>Aggregatibacter actinomycetemcomitans</i>

Amarasinghe, Jayaleka J.; Connell, Terry D.; Scannapieco, Frank A.; Haase, Elaine M.

doi:10.1111/j.2041-1014.2012.00645.x

Cited by 15 publications

(16 citation statements)

References 63 publications

(138 reference statements)

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“…Bioinformatics is also an important and less expensive tool to complement or replace the searches for regulatory RNAs in microorganisms and has been used with success (Tesorero et al 2013), including the work with the Pasteurellaceae human pathogen A. actinomycetemcomitans (Amarasinghe et al 2012). Although the computational prediction of sRNA candidates greatly diminishes the costs and time of initial experiments, the difficulties in handling algorithms generally limits their use by most biologists.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, little is known about the role of sRNAs in other Pasteurellaceae. The first study of these regulators in this family was performed on the human oral pathogen Aggregatibacter actinomycetemcomitans, in which three novel iron-regulated sRNAs were identified (Amarasinghe et al 2012), followed by the discovery of the iron-regulated HffR sRNA in Haemophilus influenzae (Santana et al 2014). Thus, the main goal of this study was to establish a strategy using free, web-accessible and userfriendly computational tools for the identification of regulatory RNAs in A. pleuropneumoniae and other bacteria from the same family.…”

Section: Introductionmentioning

confidence: 99%

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A computational strategy for the search of regulatory small RNAs in Actinobacillus pleuropneumoniae

Rossi

Bossé

et al. 2016

RNA

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Bacterial regulatory small RNAs (sRNAs) play important roles in gene regulation and are frequently connected to the expression of virulence factors in diverse bacteria. Only a few sRNAs have been described for Pasteurellaceae pathogens and no in-depth analysis of sRNAs has been described for Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, responsible for considerable losses in the swine industry. To search for sRNAs in A. pleuropneumoniae, we developed a strategy for the computational analysis of the bacterial genome by using four algorithms with different approaches, followed by experimental validation. The coding strand and expression of 17 out of 23 RNA candidates were confirmed by Northern blotting, RT-PCR, and RNA sequencing. Among them, two are likely riboswitches, three are housekeeping regulatory RNAs, two are the widely studied GcvB and 6S sRNAs, and 10 are putative novel trans-acting sRNAs, never before described for any bacteria. The latter group has several potential mRNA targets, many of which are involved with virulence, stress resistance, or metabolism, and connect the sRNAs in a complex gene regulatory network. The sRNAs identified are well conserved among the Pasteurellaceae that are evolutionarily closer to A. pleuropneumoniae and/or share the same host. Our results show that the combination of newly developed computational programs can be successfully utilized for the discovery of novel sRNAs and indicate an intricate system of gene regulation through sRNAs in A. pleuropneumoniae and in other Pasteurellaceae, thus providing clues for novel aspects of virulence that will be explored in further studies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A computational strategy for the search of regulatory small RNAs in Actinobacillus pleuropneumoniae

Rossi

Bossé

et al. 2016

RNA

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“…Sal4-induced biofilms were measured using a previously described crystal violet (CV) staining method (36). Overnight cultures of each test strain were initially standardized in fresh LB broth containing either Sal4 (15 g/ml), 23D7 (15 g/ml), an IgA isotype control of irrelevant specificity, or chemically defined medium (CDM) with no antibody, to an OD 600 of 0.05 (approximately 3 ϫ 10 7 initial CFU/ml).…”

Section: Methodsmentioning

confidence: 99%

Exposure of Salmonella enterica Serovar Typhimurium to a Protective Monoclonal IgA Triggers Exopolysaccharide Production via a Diguanylate Cyclase-Dependent Pathway

et al. 2013

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cSal4 is a monoclonal polymeric IgA antibody directed against the O antigen (O-Ag) of Salmonella enterica serovar Typhimurium (S. Typhimurium), which is sufficient to protect mice against intestinal infections from S. Typhimurium. We recently reported that the exposure of S. Typhimurium to Sal4 results in the immediate loss of flagellum-based motility, in alterations to the outer membrane (OM) integrity, and in the concomitant appearance of a mucoid phenotype that is reminiscent of cells in the earliest stages of biofilm formation. We demonstrate here that prolonged (>4 h) exposure of S. Typhimurium to Sal4 at 37°C (but not at ambient temperature [25°C]) results in measurable exopolysaccharide (EPS) accumulation and biofilm formation on both borosilicate glass surfaces and polystyrene microtiter plates. The polysaccharide produced by S. Typhimurium in response to Sal4 contains cellulose, in addition to O-Ag capsule and colanic acid. EPS production was dependent on YeaJ, a proposed inner membrane-localized diguanylate cyclase (DGC) and a known regulator of cellulose biosynthesis. An S. Typhimurium ⌬yeaJ strain was unable to produce cellulose or form a biofilm in response to Sal4. Conversely, the overexpression of yeaJ in S. Typhimurium enhanced Sal4-induced biofilm formation and resulted in increased intracellular levels of cyclic dimeric guanosine monophosphate (c-di-GMP) compared to that of a wild-type control; this strongly suggests that YeaJ is indeed a functional DGC. Based on these data, we speculate that Sal4, by virtue of its ability to associate with the O-Ag and to induce OM stress, renders S. Typhimurium avirulent by triggering a c-di-GMP-dependent signaling pathway via YeaJ that leads to the suppression of bacterial motility while simultaneously stimulating EPS production.

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“…The effect of limited concentrations of iron most likely is mediated by small regulatory RNAs (sRNA) in A. actinomycetemcomitans , though the target genes for these sRNAs, have not been yet identified [90]. The most studied periodontal pathogen, regarding the need and effects of iron on the bacterium, is likely P. gingivalis .…”

Section: Periodontitis-associated Environmental Factorsmentioning

confidence: 99%

Environmental Stimuli Shape Biofilm Formation and the Virulence of Periodontal Pathogens

Pöllänen

Paino

Ihalin

2013

IJMS

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Periodontitis is a common inflammatory disease affecting the tooth-supporting structures. It is initiated by bacteria growing as a biofilm at the gingival margin, and communication of the biofilms differs in health and disease. The bacterial composition of periodontitis-associated biofilms has been well documented and is under continual investigation. However, the roles of several host response and inflammation driven environmental stimuli on biofilm formation is not well understood. This review article addresses the effects of environmental factors such as pH, temperature, cytokines, hormones, and oxidative stress on periodontal biofilm formation and bacterial virulence.

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Novel iron‐regulated and Fur‐regulated small regulatory RNAs in Aggregatibacter actinomycetemcomitans

Cited by 15 publications

References 63 publications

A computational strategy for the search of regulatory small RNAs in Actinobacillus pleuropneumoniae

A computational strategy for the search of regulatory small RNAs in Actinobacillus pleuropneumoniae

Exposure of Salmonella enterica Serovar Typhimurium to a Protective Monoclonal IgA Triggers Exopolysaccharide Production via a Diguanylate Cyclase-Dependent Pathway

Environmental Stimuli Shape Biofilm Formation and the Virulence of Periodontal Pathogens

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