scholarly journals purL gene expression affects biofilm formation and symbiotic persistence of Photorhabdus temperata in the nematode Heterorhabditis bacteriophora

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2595-2603 ◽  
Author(s):  
Ruisheng An ◽  
Parwinder S. Grewal
Keyword(s):  
Gene Expression ◽  
Metabolic Pathway ◽  
Biofilm Formation ◽  
Heterorhabditis Bacteriophora ◽  
Bacterial Biofilm ◽  
Infective Juvenile ◽  
Plant Interactions ◽  
Symbiotic Interaction ◽  
The Impact ◽  
Photorhabdus Temperata

Extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe–plant interactions, although the exact mechanism is unknown. Here, we report the impact of a key purine metabolic gene, purL, on the symbiotic interaction between the bacterium Photorhabdus temperata and its nematode partner Heterorhabditis bacteriophora. Real-time PCR assays showed that the purL gene was upregulated in P. temperata in the nematode infective juvenile compared with artificial media. Mutation of the purL gene by in-frame deletion dramatically decreased the capacity of the bacterium to persist in infective juveniles and its ability to form biofilm in vitro. It was further demonstrated that purL gene expression was positively related to bacterial biofilm formation and the symbiotic persistence of the bacterium in nematode infective juveniles. A ΔpurL mutant lost the ability to support infective juvenile formation in the media which weakly supported biofilm formation, suggesting that a critical level of biofilm formation is required by the bacteria to support infective juvenile formation and thus establish their partnership. In addition, the defects in both biofilm formation and symbiotic ability due to the disruption of the purL gene could be partially restored by the addition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate of the purine biosynthesis pathway. Overall, these data indicate that the purine metabolic pathway is important in microbe–animal symbioses, and that it may influence symbiotic interactions at the level of biofilm formation.

scholarly journals Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence

2018 ◽  
Vol 11 (3) ◽  
pp. 227-241 ◽  
Author(s):  
Olivier Lesouhaitier ◽  
Thomas Clamens ◽  
Thibaut Rosay ◽  
Florie Desriac ◽  
Mélissande Louis ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Critical Problem ◽  
Resistant Variant ◽  
Bacterial Physiology ◽  
Gram Positive Bacteria ◽  
Biofilm Production ◽  
The Impact ◽  
Original Approach ◽  
Antibacterial Potential

Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.

scholarly journals Impact of Bacterial Biofilm Formation on In Vitro and In Vivo Activities of Antibiotics

1998 ◽  
Vol 42 (4) ◽  
pp. 895-898 ◽  
Author(s):  
Silvia Schwank ◽  
Zarko Rajacic ◽  
Werner Zimmerli ◽  
Jürg Blaser
Keyword(s):  
Animal Model ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Phenotypic Resistance ◽  
Vitro Model ◽  
The Impact ◽  
Isogenic Strains

ABSTRACT The impact of bacterial adherence on antibiotic activity was analyzed with two isogenic strains of Staphylococcus epidermidis that differ in the features of their in vitro biofilm formation. The eradication of bacteria adhering to glass beads by amikacin, levofloxacin, rifampin, or teicoplanin was studied in an animal model and in a pharmacokinetically matched in vitro model. The features of S. epidermidis RP62A that allowed it to grow on surfaces in multiple layers promoted phenotypic resistance to antibiotic treatment, whereas strain M7 failed to accumulate, despite initial adherence on surfaces and growth in suspension similar to those for RP62A. Biofilms of S. epidermidis M7 were better eradicated than those of strain RP62A in vitro (46 versus 31%;P < 0.05) as well as in the animal model (39 versus 9%; P < 0.01).

scholarly journals Disrupting Irreversible Bacterial Adhesion and Biofilm Formation with an Engineered Enzyme

2021 ◽  
Author(s):  
Holly M. Mayton ◽  
Sharon L. Walker ◽  
Bryan W. Berger
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Glycosyl Hydrolase ◽  
Cell Surface Hydrophobicity ◽  
Bacterial Biofilm ◽  
Enzyme Treatment ◽  
E Coli ◽  
Initial Adhesion ◽  
The Impact

Biofilm formation is often attributed to post-harvest bacteria persistence on fresh produce and food handling surfaces. In this study, a predicted glycosyl hydrolase enzyme was expressed, purified and validated for removal of microbial biofilms from biotic and abiotic surfaces under conditions used for chemical cleaning agents. Crystal violet biofilm staining assays revealed that 0.1 mg/mL of enzyme inhibited up to 41% of biofilm formation by E. coli O157:H7, E. coli 25922, Salmonella Typhimurium, and Listeria monocytogenes. Further, the enzyme was effective at removing mature biofilms, providing a 35% improvement over rinsing with a saline solution alone. Additionally, a parallel-plate flow cell was used to directly observe and quantify the impact of enzyme rinses on E. coli O157:H7 cells adhered to spinach leaf surfaces. The presence of 1 mg/L enzyme resulted in nearly 6 times greater detachment rate coefficients than a DI water rinse, while the total cells removed from the surface increased from 10% to 25% over the 30 minute rinse time, reversing the initial phases of biofilm formation. Enzyme treatment of all 4 cell types resulted in significantly reduced cell surface hydrophobicity, and collapse of negatively stained E. coli 25922 cells imaged by electron microscopy, suggesting potential polysaccharide surface modification of enzyme-treated bacteria. Collectively, these results point to the broad substrate specificity and robustness of the enzyme to different types of biofilm stages, solution conditions and pathogen biofilm types, and may be useful as a method for removal or inhibition of bacterial biofilm formation. IMPORTANCE In this study, the ability of an engineered enzyme to reduce bacterial adhesion and biofilm formation of several foodborne pathogens was demonstrated, representing a promising option for enhancing or replacing chlorine and other chemical sanitizers in food processing applications. Specifically, significant reductions of the pathogens Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms are observed, as well as reduction in initial adhesion. Enzymes have the added benefits of being green, sustainable alternatives to chemical sanitizers, as well as having minimal impact on food properties, in contrast with many alternative antimicrobial options such as bleach that aim to minimize food safety risks.

scholarly journals In-Vitro Evaluation of Biological Activity of New Series of 1, 3, 4-Oxadiazole Derivatives Against Bap Gene Expression in Acinetobacter bumanni Biofilm

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Sedigheh Akbarnezhad Ghareh Lar ◽  
Nakisa Zarrabi Ahrabi ◽  
Yasin SarveAhrabi
Keyword(s):  
Biofilm Formation ◽  
Functional Group ◽  
Biological Activities ◽  
Antimicrobial Properties ◽  
Housekeeping Gene ◽  
Bacterial Biofilm ◽  
Wide Range ◽  
Oxadiazole Derivatives ◽  
The Impact

Background: Acinetobacter bumanni is one of the most common opportunistic pathogens in health centers that is resistant to many antibiotics due to biofilm production. 1, 3, 4-oxadiazoles have a wide range of biological activities. Objectives: The aim of this research was to examine the impact of new 1, 3, 4-oxadiazole derivatives on the expression of biofilm-associated surface protein (Bap), playing an important role in promoting the biofilm formation ability of A. baumannii strains. Methods: Derivatives of 1, 3, 4-oxadiazole were synthesized through a one-step synthesis. A. baumannii strains were identified and isolated in the laboratory. The antimicrobial properties of the synthesized materials against the isolated strains were investigated. DNA, RNA, and cDNA were extracted, and the relative expression of BAP gene in A. baumannii isolates was evaluated by real-time polymerase chain reaction. Results: The compound with methoxyphenyl functional group with MIC = 62.50 mg/mL had the best inhibitory performance among all derivatives. Also, the combination of 4i reduced the expression of the Bap gene by about 24 times, but it had no effect on the expression of the 16srRNA housekeeping gene. Conclusions: 1, 3, 4-oxadiazole derivatives, especially the methoxyphenyl functional group, act as an inhibitor of bacterial biofilm formation and have the potential to be used in the pharmaceutical and biological industries.

scholarly journals In Vitro and In Silico Evaluation of Biological Activity of a New Series of Oxadiazole Compounds Against Esp Gene Expression in Enterococcus faecalis Biofilm

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Sepideh Ghameshlouei ◽  
Nakisa Zarrabi Ahrabi ◽  
Yasin SarveAhrabi
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Biological Activities ◽  
Control Sample ◽  
Surface Protein ◽  
Bacterial Biofilm ◽  
Receptor Binding Site ◽  
Wide Range ◽  
Oxadiazole Derivatives ◽  
The Impact

Background: The enterococcal surface protein (Esp) is a high-molecular-weight surface protein of biofilm creating agent in Enterococcus faecalis. Oxadiazoles have a wide range of biological activities. Objective: This research aimed to examine the impact of new oxadiazole derivatives on the expression of Esp, playing an important role in promoting the biofilm formation ability of drug-resistant E. faecalis strains. Method: 1, 3, 4-oxadiazole derivatives were synthesized through a one-step synthesis. E. faecalis strains were collected and isolated from hospitals in Tehran. The antimicrobial properties of the synthesized materials against the isolated strains were investigated. RNA, DNA, and cDNA were extracted, and the relative expression of Esp in E. faecalis isolates was evaluated by real-time PCR. Docking study was performed by AutoDock vina software, and the resulting docking poses were analyzed using Discovery Studio 4.5 Client software. Results: The use of synthesized derivatives changed the Esp expression level in different isolates compared to the control sample. The two compounds containing naphthalene (4f) and methoxyphenyl (4g) caused respectively a 2-fold and a 3-fold decrease in Esp expression compared to the control sample. The compound 4f with the best binding energy among the compounds (-9.2) had the most hydrogen and hydrophobic bonds with the receptor-binding site. Conclusions: 1, 3, 4-oxadiazole derivatives, especially naphthalene and methoxyphenyl, act as inhibitors of bacterial biofilm formation and can be used in the pharmaceutical and biological industries.

scholarly journals Insights into the Noncoding RNome of Nitrogen-Fixing Endosymbiotic α-Proteobacteria

2013 ◽  
Vol 26 (2) ◽  
pp. 160-167 ◽  
Author(s):  
José I. Jiménez-Zurdo ◽  
Claudio Valverde ◽  
Anke Becker
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Regulation Of Gene Expression ◽  
Living Environment ◽  
Large Set ◽  
Nitrogen Fixing ◽  
Symbiotic Interaction ◽  
Animal Pathogens ◽  
Wide Range ◽  
The Impact

Symbiotic chronic infection of legumes by rhizobia involves transition of invading bacteria from a free-living environment in soil to an intracellular state as differentiated nitrogen-fixing bacteroids within the nodules elicited in the host plant. The adaptive flexibility demanded by this complex lifestyle is likely facilitated by the large set of regulatory proteins encoded by rhizobial genomes. However, proteins are not the only relevant players in the regulation of gene expression in bacteria. Large-scale high-throughput analysis of prokaryotic genomes is evidencing the expression of an unexpected plethora of small untranslated transcripts (sRNAs) with housekeeping or regulatory roles. sRNAs mostly act in response to environmental cues as post-transcriptional regulators of gene expression through protein-assisted base-pairing interactions with target mRNAs. Riboregulation contributes to fine-tune a wide range of bacterial processes which, in intracellular animal pathogens, largely compromise virulence traits. Here, we summarize the incipient knowledge about the noncoding RNome structure of nitrogen-fixing endosymbiotic bacteria as inferred from genome-wide searches for sRNA genes in the alfalfa partner Sinorhizobium meliloti and further comparative genomics analysis. The biology of relevant S. meliloti RNA chaperones (e.g., Hfq) is also reviewed as a first global indicator of the impact of riboregulation in the establishment of the symbiotic interaction.

Effects of inducer levels on a recombinant bacterial biofilm formation and gene expression

1994 ◽  
Vol 16 (9) ◽  
pp. 903-908 ◽  
Author(s):  
Ching-Tsan Huang ◽  
Steven W. Peretti ◽  
James D. Bryers
Keyword(s):  
Gene Expression ◽  
Biofilm Formation ◽  
Bacterial Biofilm

scholarly journals Hybrid histidine kinase BinK represses Vibrio fischeri biofilm signaling at multiple developmental stages

2021 ◽  
Author(s):  
Denise A. Ludvik ◽  
Katherine M. Bultman ◽  
Mark J. Mandel
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Histidine Kinase ◽  
Biofilm Formation ◽  
Vibrio Fischeri ◽  
Bacterial Biofilm ◽  
Negative Regulator ◽  
Light Organ ◽  
Host Colonization ◽  
Hybrid Histidine Kinase

ABSTRACTThe symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and its exclusive light-organ symbiont, Vibrio fischeri, provides a natural system in which to study host-microbe specificity and gene regulation during the establishment of a mutually-beneficial symbiosis. Colonization of the host relies on bacterial biofilm-like aggregation in the squid mucus field. Symbiotic biofilm formation is controlled by a two-component signaling (TCS) system consisting of regulators RscS-SypF-SypG, which together direct transcription of the Syp symbiotic polysaccharide. TCS systems are broadly important for bacteria to sense environmental cues and then direct changes in behavior. Previously, we identified hybrid histidine kinase BinK as a strong negative regulator of V. fischeri biofilm regulation, and here we further explore the function of BinK. To inhibit biofilm formation, BinK requires the predicted phosphorylation sites in both the histidine kinase (H362) and receiver (D794) domains. Furthermore, we show that a strain lacking BinK yields RscS non-essential for host colonization, and imaging of aggregate size revealed no benefit to the presence of RscS in a background lacking BinK. Strains lacking RscS still suffered in competition, suggesting another function for the protein. Finally, we show that BinK functions to inhibit biofilm gene expression in the light organ crypts, providing evidence for biofilm gene regulation at later stages of host colonization. Overall, this study provides direct evidence for opposing activities of RscS and BinK and yields novel insights into biofilm regulation during the maturation of a beneficial symbiosis.IMPORTANCEBacteria are often in a biofilm state, and transitions between planktonic and biofilm lifestyles are important for pathogenic, beneficial, and environmental microbes. The critical nature of biofilm formation during Vibrio fischeri colonization of the Hawaiian bobtail squid light organ provides an opportunity to study development of this process in vivo using a combination of genetic and imaging approaches. The current work refines the signaling circuitry of the biofilm pathway in V. fischeri, provides evidence that biofilm regulatory changes occur in the host, and identifies BinK as one of the regulators of that process. This study provides information about how bacteria regulate biofilm gene expression in an intact animal host.

scholarly journals Hybrid histidine kinase BinK represses Vibrio fischeri biofilm signaling at multiple developmental stages

2021 ◽  
Author(s):  
Denise A. Ludvik ◽  
Katherine M. Bultman ◽  
Mark J. Mandel
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Histidine Kinase ◽  
Biofilm Formation ◽  
Vibrio Fischeri ◽  
Bacterial Biofilm ◽  
Negative Regulator ◽  
Light Organ ◽  
Host Colonization ◽  
Hybrid Histidine Kinase

The symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and its exclusive light-organ symbiont, Vibrio fischeri, provides a natural system in which to study host-microbe specificity and gene regulation during the establishment of a mutually-beneficial symbiosis. Colonization of the host relies on bacterial biofilm-like aggregation in the squid mucus field. Symbiotic biofilm formation is controlled by a two-component signaling (TCS) system consisting of regulators RscS-SypF-SypG, which together direct transcription of the Syp symbiotic polysaccharide. TCS systems are broadly important for bacteria to sense environmental cues and then direct changes in behavior. Previously, we identified hybrid histidine kinase BinK as a strong negative regulator of V. fischeri biofilm regulation, and here we further explore the function of BinK. To inhibit biofilm formation, BinK requires the predicted phosphorylation sites in both the histidine kinase (H362) and receiver (D794) domains. Furthermore, we show that RscS is not essential for host colonization when binK is deleted from strain ES114, and imaging of aggregate size revealed no benefit to the presence of RscS in a background lacking BinK. Strains lacking RscS still suffered in competition. Finally, we show that BinK functions to inhibit biofilm gene expression in the light organ crypts, providing evidence for biofilm gene regulation at later stages of host colonization. Overall, this study provides direct evidence for opposing activities of RscS and BinK and yields novel insights into biofilm regulation during the maturation of a beneficial symbiosis. IMPORTANCE Bacteria are often in a biofilm state, and transitions between planktonic and biofilm lifestyles are important for pathogenic, beneficial, and environmental microbes. The critical nature of biofilm formation during Vibrio fischeri colonization of the Hawaiian bobtail squid light organ provides an opportunity to study development of this process in vivo using a combination of genetic and imaging approaches. The current work refines the signaling circuitry of the biofilm pathway in V. fischeri, provides evidence that biofilm regulatory changes occur in the host, and identifies BinK as one of the regulators of that process. This study provides information about how bacteria regulate biofilm gene expression in an intact animal host.

scholarly journals Cyclic di-AMP Acts as an Extracellular Signal That ImpactsBacillus subtilisBiofilm Formation and Plant Attachment

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Loni Townsley ◽  
Sarah M. Yannarell ◽  
Tuanh Ngoc Huynh ◽  
Joshua J. Woodward ◽  
Elizabeth A. Shank
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Intracellular Signaling ◽  
Biofilm Formation ◽  
Plant Root ◽  
Second Messenger ◽  
Pathogen Resistance ◽  
Plant Roots ◽  
Extracellular Signal ◽  
The Impact

ABSTRACTThere is a growing appreciation for the impact that bacteria have on higher organisms. Plant roots often harbor beneficial microbes, such as the Gram-positive rhizobacteriumBacillus subtilis, that influence their growth and susceptibility to disease. The ability to form surface-attached microbial communities called biofilms is crucial for the ability ofB. subtilisto adhere to and protect plant roots. In this study, strains harboring deletions of theB. subtilisgenes known to synthesize and degrade the second messenger cyclic di-adenylate monophosphate (c-di-AMP) were examined for their involvement in biofilm formation and plant attachment. We found that intracellular production of c-di-AMP impacts colony biofilm architecture, biofilm gene expression, and plant attachment inB. subtilis. We also show thatB. subtilissecretes c-di-AMP and that putative c-di-AMP transporters impact biofilm formation and plant root colonization. Taken together, our data describe a new role for c-di-AMP as a chemical signal that affects important cellular processes in the environmentally and agriculturally important soil bacteriumB. subtilis. These results suggest that the “intracellular” signaling molecule c-di-AMP may also play a previously unappreciated role in interbacterial cell-cell communication within plant microbiomes.IMPORTANCEPlants harbor bacterial communities on their roots that can significantly impact their growth and pathogen resistance. In most cases, however, the signals that mediate host-microbe and microbe-microbe interactions within these communities are unknown. A detailed understanding of these interaction mechanisms could facilitate the manipulation of these communities for agricultural or environmental purposes.Bacillus subtilisis a plant-growth-promoting bacterium that adheres to roots by forming biofilms. We therefore began by exploring signals that might impact its biofilm formation. We found thatB. subtilissecretes c-di-AMP and that the ability to produce, degrade, or transport cyclic di-adenylate monophosphate (c-di-AMP; a common bacterial second messenger) affectsB. subtilisbiofilm gene expression and plant attachment. To our knowledge, this is the first demonstration of c-di-AMP impacting a mutualist host-microbe association and suggests that c-di-AMP may function as a previously unappreciated extracellular signal able to mediate interactions within plant microbiomes.

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