scholarly journals TatD DNases Contribute to Biofilm Formation and Virulence in Trueperella pyogenes

2021 ◽  
Vol 12 ◽  
Author(s):  
Zehui Zhang ◽  
Yinfeng Liang ◽  
Lihui Yu ◽  
Menghan Chen ◽  
Yuru Guo ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Wild Type Strain ◽  
Divalent Cations ◽  
Bacterial Load ◽  
Economic Losses ◽  
Wild Type ◽  
Trueperella Pyogenes ◽  
Mutant Strains ◽  
Sequence Characteristics

TatD DNases are conserved proteins in a variety of organisms and are considered potential virulence factors in Plasmodium falciparum and Streptococcus pneumoniae. However, the function of TatD DNases has not yet been determined in Trueperella pyogenes, which causes various infections in animals and leads to economic losses. In this study, we describe the roles of TatD DNases in T. pyogenes (TpTatDs). A bioinformatics analysis was performed to investigate the sequence characteristics of TpTatDs, and then the ability of recombinant TatD proteins to hydrolyze DNA was determined in the presence of divalent cations. Moreover, we constructed tatD-deficient mutants. The biofilms formed by the wild-type and mutant strains were observed under a microscope. The mortality and bacterial load in the spleen of mice infected with the wild-type strain and tatD-deficient mutants were determined to obtain insights into the role of TatDs in the virulence of T. pyogenes. Two TatD DNases were identified in T. pyogenes. They were Mg2+-dependent DNases and exhibited DNA endonuclease activity. Compared with those formed by the parental strain, biofilms formed by mutants showed a significantly reduced thickness and biomass. Moreover, mutants produced a lower bacterial load in the spleen of mice and compromised virulence. Our data indicated that TatD DNases in T. pyogenes are involved in biofilm formation and required for virulence during infections.

scholarly journals Role of CpALS4790 and CpALS0660 in Candida parapsilosis Virulence: Evidence from a Murine Model of Vaginal Candidiasis

2020 ◽  
Vol 6 (2) ◽  
pp. 86
Author(s):  
Marina Zoppo ◽  
Fabrizio Fiorentini ◽  
Cosmeri Rizzato ◽  
Mariagrazia Di Luca ◽  
Antonella Lupetti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Murine Model ◽  
Type Strain ◽  
Wild Type Strain ◽  
Candida Parapsilosis ◽  
Vaginal Candidiasis ◽  
Phenotypic Characterization ◽  
Wild Type ◽  
Mutant Strains

The Candida parapsilosis genome encodes for five agglutinin-like sequence (Als) cell-wall glycoproteins involved in adhesion to biotic and abiotic surfaces. The work presented here is aimed at analyzing the role of the two still uncharacterized ALS genes in C. parapsilosis, CpALS4790 and CpALS0660, by the generation and characterization of CpALS4790 and CpALS066 single mutant strains. Phenotypic characterization showed that both mutant strains behaved as the parental wild type strain regarding growth rate in liquid/solid media supplemented with cell-wall perturbing agents, and in the ability to produce pseudohyphae. Interestingly, the ability of the CpALS0660 null mutant to adhere to human buccal epithelial cells (HBECs) was not altered when compared with the wild-type strain, whereas deletion of CpALS4790 led to a significant loss of the adhesion capability. RT-qPCR analysis performed on the mutant strains in co-incubation with HBECs did not highlight significant changes in the expression levels of others ALS genes. In vivo experiments in a murine model of vaginal candidiasis indicated a significant reduction in CFUs recovered from BALB/C mice infected with each mutant strain in comparison to those infected with the wild type strain, confirming the involvement of CpAls4790 and CpAls5600 proteins in C. parapsilosis vaginal candidiasis in mice.

scholarly journals Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation

2020 ◽  
Vol 8 (1) ◽  
pp. 70 ◽  
Author(s):  
Bhumika Shokeen ◽  
Jane Park ◽  
Emily Duong ◽  
Sonam Rambhia ◽  
Manash Paul ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Fusobacterium Nucleatum ◽  
Interspecies Interaction ◽  
Wild Type ◽  
Oral Epithelial Cells ◽  
Small Proteins ◽  
Mutant Strains ◽  
Oral Epithelial ◽  
Wild Type Parent

RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacterium nucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcus gordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S. gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.

scholarly journals The Role of a Host-Induced Arginase of Xanthomonas oryzae pv. oryzae in Promoting Virulence on Rice

2019 ◽  
Vol 109 (11) ◽  
pp. 1869-1877
Author(s):  
Yuqiang Zhang ◽  
Guichun Wu ◽  
Ian Palmer ◽  
Bo Wang ◽  
Guoliang Qian ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Blight ◽  
Wild Type Strain ◽  
Bacterial Pathogen ◽  
Extracellular Polysaccharide ◽  
Rice Cultivar ◽  
Xanthomonas Oryzae ◽  
Wild Type ◽  
Bacterial Blight Of Rice

The plant bacterial pathogen Xanthomonas oryzae pv. oryzae causes bacterial blight of rice, which is one of the most destructive rice diseases prevalent in Asia and parts of Africa. Despite many years of research, how X. oryzae pv. oryzae causes bacterial blight of rice is still not completely understood. Here, we show that the loss of the rocF gene caused a significant decrease in the virulence of X. oryzae pv. oryzae in the susceptible rice cultivar IR24. Bioinformatics analysis demonstrated that rocF encodes arginase. Quantitative real-time PCR and Western blot assays revealed that rocF expression was significantly induced by rice and arginine. The rocF deletion mutant strain showed elevated sensitivity to hydrogen peroxide, reduced extracellular polysaccharide (EPS) production, and reduced biofilm formation, all of which are important determinants for the full virulence of X. oryzae pv. oryzae, compared with the wild-type strain. Taken together, the results of this study revealed a mechanism by which a bacterial arginase is required for the full virulence of X. oryzae pv. oryzae on rice because of its contribution to tolerance to reactive oxygen species, EPS production, and biofilm formation.

scholarly journals The RcsCB His-Asp Phosphorelay System Is Essential To Overcome Chlorpromazine-Induced Stress in Escherichia coli

2002 ◽  
Vol 184 (10) ◽  
pp. 2850-2853 ◽  
Author(s):  
Annie Conter ◽  
Rachel Sturny ◽  
Claude Gutierrez ◽  
Kaymeuang Cam
Keyword(s):  
Escherichia Coli ◽  
Type Strain ◽  
Wild Type Strain ◽  
Cell Envelope ◽  
Wild Type ◽  
E Coli ◽  
Induced Stress ◽  
Mutant Strains ◽  
Molecular Nature

ABSTRACT The RcsCB His-Asp phosphorelay system regulates the expression of several genes of Escherichia coli, but the molecular nature of the inducing signal is still unknown. We show here that treatment of an exponentially growing culture of E. coli with the cationic amphipathic compound chlorpromazine (CPZ) stimulates expression of a set of genes positively regulated by the RcsCB system. This induction is abolished in rcsB or rcsC mutant strains. In addition, treatment with CPZ inhibits growth. The wild-type strain is able to recover from this inhibition and resume growth after a period of adaptation. In contrast, strains deficient in the RcsCB His-Asp phosphorelay system are hypersensitive to CPZ. These results suggest that cells must express specific RcsCB-regulated genes in order to cope with the CPZ-induced stress. This is the first report of the essential role of the RcsCB system in a stress situation. These results also strengthen the notion that alterations of the cell envelope induce a signal recognized by the RcsC sensor.

scholarly journals Influence of thePhotorhabdus luminescensPhosphomannose Isomerase Gene,manA, on Mannose Utilization, Exopolysaccharide Structure, and Biofilm Formation

2010 ◽  
Vol 77 (3) ◽  
pp. 776-785 ◽  
Author(s):  
Matthew R. Amos ◽  
Maria Sanchez-Contreras ◽  
Robert W. Jackson ◽  
Xavier Muñoz-Berbel ◽  
Todd A. Ciche ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Wild Type Strain ◽  
Compositional Analysis ◽  
Extracellular Polysaccharide ◽  
Major Effect ◽  
Photorhabdus Luminescens ◽  
Wild Type ◽  
Abiotic Surfaces ◽  
Structural Matrix

ABSTRACTExtracellular polysaccharide (EPS) is produced by diverse bacterial pathogens and fulfills assorted roles, including providing a structural matrix for biofilm formation and more specific functions in virulence, such as protection against immune defenses. We report here the first investigation of some of the genes important for biofilm formation inPhotorhabdus luminescensand demonstrate the key role of the phosphomannose isomerase gene,manA, in the structure of functional EPS. Phenotypic analyses of amanA-deficient mutant showed the importance of EPS in motility, insect virulence, and biofilm formation on abiotic surfaces as well as the requirement of this gene for the use of mannose as the sole carbon source. Conversely, this defect had no apparent impact on symbiosis with the heterorhabditid nematode vector. A more detailed analysis of biofilm formation revealed that themanAmutant was able to attach to surfaces with the same efficiency as that of the wild-type strain but could not develop the more extended biofilm matrix structures. A compositional analysis ofP. luminescensEPS reveals how themanAmutation has a major effect on the formation of a complete, branched EPS.

scholarly journals Mutagenic strategies against luxS gene affect the early stage of biofilm formation of Campylobacter jejuni

2021 ◽  
Author(s):  
Martin Tereň ◽  
Ekaterina Shagieva ◽  
Lucie Vondrakova ◽  
Jitka Viktorova ◽  
Viviana Svarcova ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Early Stage ◽  
Wild Type ◽  
Genetic Determinants ◽  
Autoinducer 2 ◽  
Naturally Occurring ◽  
Mutant Strains ◽  
The Impact

Abstract Currently, it is clear that the luxS gene has an impact on the process of biofilm formation in Campylobacter jejuni. However, even within the species naturally occurring strains of Campylobacter lacking the luxS gene exist, which can form biofilms. In order to better understand the genetic determinants and the role of quorum sensing through the LuxS/AI-2 pathway in biofilm formation, a set of mutant/complemented strains of C. jejuni 81–176 were prepared. Additionally, the impact of the mutagenic strategy used against the luxS gene was investigated. Biofilm formation was affected by both the presence and absence of the luxS gene, and by the mutagenic strategy used. Analysis by CLSM showed that all mutant strains formed significantly less biofilm mass when compared to the wild-type. Interestingly, the deletion mutant (∆luxS) showed a larger decrease in biofilm mass than the substitution (∙luxS) and insertional inactivated (⸬luxS) mutants, even though all the mutant strains lost the ability to produce autoinducer-2 molecules. Moreover, the biofilm of the ∆luxS mutant lacked the characteristic microcolonies observed in all other strains. The complementation of all mutant strains resulted in restored ability to produce AI-2, to form a complex biofilm, and to develop microcolonies at the level of the wild-type.

scholarly journals Role of the Type VI Secretion System in the Pathogenicity of Pseudomonas syringae pv. actinidiae, the Causative Agent of Kiwifruit Bacterial Canker

2021 ◽  
Vol 12 ◽  
Author(s):  
Nana Wang ◽  
Ning Han ◽  
Runze Tian ◽  
Jiliang Chen ◽  
Xiaoning Gao ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Pseudomonas Syringae ◽  
Biofilm Formation ◽  
Wild Type Strain ◽  
Deletion Mutants ◽  
Wild Type ◽  
Type Vi Secretion System ◽  
Bacterial Competition ◽  
Type Vi Secretion

The type VI secretion system (T6SS), a macromolecular machine, plays an important role in the pathogenicity of many Gram-negative bacteria. However, the role of T6SS in the pathogenicity of Pseudomonas syringae pv. actinidiae (Psa), the pathogen of kiwifruit bacterial canker, is yet to be studied. Here, we found a T6SS gene cluster consisting of 13 core genes (A-J) in the genome of Psa M228 based on a genome-wide analysis. To determine whether the T6SS gene cluster affects the pathogenicity of Psa M228, T6SS and its 13 core gene deletion mutants were constructed and their pathogenicity was determined. The deletion mutants showed different degrees of reduction in pathogenicity compared with the wild-type strain M228; in tssM and tssJ mutants, pathogenicity was significantly reduced by 78.7 and 71.3%, respectively. The pathogenicity results were also confirmed by electron microscopy. To further confirm that the reduction in pathogenicity is related to the function of T6SS, we selected the T6SS gene cluster, comprising tssM and tssJ, for further analyses. Western blot results revealed that tssM and tssJ were necessary for hemolytic co-regulatory protein secretion, indicating that they encode a functional T6SS. Further, we explored the mechanism by which T6SS affects the pathogenicity of Psa M228. The ability of bacterial competition, biofilm formation, hydrogen peroxide tolerance, and proteolytic activity were all weakened in the deletion mutants M228ΔT6SS, M228ΔtssM, and M228ΔtssJ. All these properties of the two gene complementation mutants were restored to the same levels as those of the wild-type strain, M228. Quantitative real-time results showed that during the interaction between the deletion mutant M228ΔT6SS and the host, expression levels of T3SS transcriptional regulatory gene hrpR, structural genes hrpZ, hrcC, hopP1, and effector genes hopH1 and hopM1 were down-regulated at different levels. Taken together, our data provide evidence for the first time that the T6SS plays an important role in the pathogenicity of Psa, probably via effects on bacterial competition, biofilm formation, and environmental adaptability. Moreover, a complicated relationship exists between T6SS and T3SS.

scholarly journals The OxyR homologue in Tannerella forsythia regulates expression of oxidative stress responses and biofilm formation

Microbiology ◽  
2009 ◽  
Vol 155 (6) ◽  
pp. 1912-1922 ◽  
Author(s):  
Kiyonobu Honma ◽  
Elina Mishima ◽  
Satoru Inagaki ◽  
Ashu Sharma
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Oxidative Stress Response ◽  
Wild Type ◽  
Tannerella Forsythia ◽  
Antioxidant Genes

Tannerella forsythia is an anaerobic periodontal pathogen that encounters constant oxidative stress in the human oral cavity due to exposure to air and reactive oxidative species from coexisting dental plaque bacteria as well as leukocytes. In this study, we sought to characterize a T. forsythia ORF with close similarity to bacterial oxidative stress response sensor protein OxyR. To analyse the role of this OxyR homologue, a gene deletion mutant was constructed and characterized. Aerotolerance, survival after hydrogen peroxide challenge and transcription levels of known bacterial antioxidant genes were then determined. Since an association between oxidative stress and biofilm formation has been observed in bacterial systems, we also investigated the role of the OxyR protein in biofilm development by T. forsythia. Our results showed that aerotolerance, sensitivity to peroxide challenge and the expression of oxidative stress response genes were significantly reduced in the mutant as compared with the wild-type strain. Moreover, the results of biofilm analyses showed that, as compared with the wild-type strain, the oxyR mutant showed significantly less autoaggregation and a reduced ability to form mixed biofilms with Fusobacterium nucleatum. In conclusion, a gene annotated in the T. forsythia genome as an oxyR homologue was characterized. Our studies showed that the oxyR homologue in T. forsythia constitutively activates antioxidant genes involved in resistance to peroxides as well as oxygen stress (aerotolerance). In addition, the oxyR deletion attenuates biofilm formation in T. forsythia.

scholarly journals A Pleiotropic Regulator, Frp, Affects Exopolysaccharide Synthesis, Biofilm Formation, and Competence Development in Streptococcus mutans

2006 ◽  
Vol 74 (8) ◽  
pp. 4581-4589 ◽  
Author(s):  
Bing Wang ◽  
Howard K. Kuramitsu
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Wild Type Strain ◽  
Transformation Efficiency ◽  
Competence Development ◽  
Wild Type ◽  
Cellular Functions ◽  
In The Wild ◽  
Pleiotropic Regulator

ABSTRACT Exopolysaccharide synthesis, biofilm formation, and competence are important physiologic functions and virulence factors for Streptococcus mutans. In this study, we report the role of Frp, a transcriptional regulator, on the regulation of these traits crucial to pathogenesis. An Frp-deficient mutant showed decreased transcription of several genes important in virulence, including those encoding fructosyltransferase (Ftf), glucosyltransferase B (GtfB), and GtfC, by reverse transcription and quantitative real-time PCR. Expression of Ftf was decreased in the frp mutant, as assessed by Western blotting as well as by the activity assays. Frp deficiency also inhibited the production of GtfB in the presence of glucose and sucrose as well as the production of GtfC in the presence of glucose. As a consequence of the effects on GtfB and -C, sucrose-induced biofilm formation was decreased in the frp mutant. The expression of competence mediated by the competence-signaling peptide (CSP) system, as assessed by comC gene transcription, was attenuated in the frp mutant. As a result, the transformation efficiency was decreased in the frp mutant but was partially restored by adding synthetic CSP. Transcription of the frp gene was significantly increased in the frp mutant under all conditions tested, indicating that frp transcription is autoregulated. Furthermore, complementation of the frp gene in the frp mutant restored transcription of the affected genes to levels similar to those in the wild-type strain. These results suggest that Frp is a novel pleiotropic effector of multiple cellular functions and is involved in the modulation of exopolysaccharide synthesis, sucrose-dependent biofilm formation, and competence development.

scholarly journals The RNA Chaperone Hfq Promotes Fitness of Actinobacillus pleuropneumoniae during Porcine Pleuropneumonia

2013 ◽  
Vol 81 (8) ◽  
pp. 2952-2961 ◽  
Author(s):  
Sargurunathan Subashchandrabose ◽  
Rhiannon M. Leveque ◽  
Roy N. Kirkwood ◽  
Matti Kiupel ◽  
Martha H. Mulks
Keyword(s):  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Actinobacillus Pleuropneumoniae ◽  
Wild Type ◽  
Content Type ◽  
Porcine Pleuropneumonia ◽  
Porcine Lungs

ABSTRACTActinobacillus pleuropneumoniaeis the etiological agent of porcine pleuropneumonia, an economically important disease of pigs. Thehfqgene inA. pleuropneumoniae, encoding the RNA chaperone and posttranscriptional regulator Hfq, is upregulated during infection of porcine lungs. To investigate the role of thisin vivo-induced gene inA. pleuropneumoniae, anhfqmutant strain was constructed. Thehfqmutant was defective in biofilm formation on abiotic surfaces. The level ofpgaCtranscript, encoding the biosynthesis of poly-β-1,6-N-acetylglucosamine (PNAG), a major biofilm matrix component, was lower and PNAG content was 10-fold lower in thehfqmutant than in the wild-type strain. When outer membrane proteins were examined, cysteine synthase, implicated in resistance to oxidative stress and tellurite, was not found at detectable levels in the absence of Hfq. Thehfqmutant displayed enhanced sensitivity to superoxide generated by methyl viologen and tellurite. These phenotypes were readily reversed by complementation with thehfqgene expressed from its native promoter. The role of Hfq in the fitness ofA. pleuropneumoniaewas assessed in a natural host infection model. Thehfqmutant failed to colonize porcine lungs and was outcompeted by the wild-type strain (median competitive index of 2 × 10−5). Our data demonstrate that thein vivo-induced genehfqis involved in the regulation of PNAG-dependent biofilm formation, resistance to superoxide stress, and the fitness and virulence ofA. pleuropneumoniaein pigs and begin to elucidate the role of anin vivo-induced gene in the pathogenesis of pleuropneumonia.

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