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Journal of Agricultural and Food... Mar 2023Plants can recruit beneficial microbes to help improve their fitness under abiotic or biotic stress. Our previous studies found that could enrich beneficial sp. B36 in...
Plants can recruit beneficial microbes to help improve their fitness under abiotic or biotic stress. Our previous studies found that could enrich beneficial sp. B36 in the rhizosphere soil under autotoxic ginsenoside stress. Here, we clarified that ginsenoside stress activated the phenylpropanoid biosynthesis and α-linolenic acid metabolism pathways of roots to increase the secretion of cinnamic acid, 2-dodecenoic acid, and 12-oxo-phytodienoic acid. These metabolites could promote the growth of B36. Importantly, cinnamic acid could simultaneously promote the chemotaxis and growth of B36, enhance the colonization of B36 in the rhizosphere, and eventually increase the survival rate of . Overall, the plants could promote the growth and colonization of beneficial bacteria through key metabolites in root exudates under autotoxin stress. This finding will facilitate the practical application of beneficial bacteria in agricultural production and lead to successful and reproducible biocontrol efficacy by the exogenous addition of key metabolites.
Topics: Transcriptome; Ginsenosides; Plant Roots; Bacteria; Plants; Exudates and Transudates; Rhizosphere; Soil Microbiology
PubMed: 36893094
DOI: 10.1021/acs.jafc.3c00311 -
Journal of Agricultural and Food... Mar 2021is a Gram-positive endospore-forming foodborne pathogen that causes lethal food poisoning and significant economic losses, usually through biofilm- and...
is a Gram-positive endospore-forming foodborne pathogen that causes lethal food poisoning and significant economic losses, usually through biofilm- and endospore-induced recurrent cross- and postprocessing contamination. Due to the lack of critical inhibitory targets and control strategies, biofilm contamination is a problem that urgently needs a solution. In this study, the antibacterial and antibiofilm activities of several natural potential bacterial quorum sensing (QS) interferers, a group of spice-originated monoterpenoids, were screened, and terpinen-4-ol effectively inhibited growth and biofilm and spore germination with minimum growth inhibition and 50% biofilm inhibitory concentrations of 8 and 2 μmol/mL, respectively. FESEM/CLSM and phenotypic research illustrated that in addition to a decrease in the number of attached cells, (+)-terpinen-4-ol also obviously reduced extracellular matrix synthesis, especially exopolysaccharides, and inhibited the swarming motility and protease activity of . (+)-Terpinen-4-ol did not exert a significant effect on AI-2 signals in . Accordingly, the -produced interspecies QS signals diffusing signal factors (DSFs, C8-C15) and diketopiperazines (DKPs) were detected and identified here, which suppressed biofilm formation in a concentration-dependent manner. (+)-Terpinen-4-ol significantly increased the levels of specific DSF and DKP signals in and down-regulated the gene expression of some homologues in transcription level. Moreover, both DKPs and DSFs inhibited swarming motility and protease activity in , while just the DSF signals 2-dodecenoic acid and 11-methyl-2-dodecenoic acid inhibited exopolysaccharide synthesis like (+)-terpinen-4-ol. In summary, strains were found to produce nine DSF- and six DKP-type QS signaling molecules, which repressed biofilm formation. (+)-Terpinen-4-ol was confirmed to be a promising antibacterial and antibiofilm agent against upregulating DSFs and DKPs levels, and it could target the critical genes for DSFs turnover.
Topics: Bacillus cereus; Biofilms; Diketopiperazines; Quorum Sensing; Terpenes
PubMed: 33724028
DOI: 10.1021/acs.jafc.0c07826 -
Applied and Environmental Microbiology May 2021Quorum-sensing (QS) signals are widely employed by bacteria to regulate biological functions in response to cell densities. Previous studies showed that Burkholderia...
Quorum-sensing (QS) signals are widely employed by bacteria to regulate biological functions in response to cell densities. Previous studies showed that Burkholderia cenocepacia mostly utilizes two types of QS systems, including the -acylhomoserine lactone (AHL) and -2-dodecenoic acid (BDSF) systems, to regulate biological functions. We demonstrated here that a LysR family transcriptional regulator, Bcal3178, controls the QS-regulated phenotypes, including biofilm formation and protease production, in B. cenocepacia H111. Expression of at the transcriptional level was obviously downregulated in both the AHL-deficient and BDSF-deficient mutant strains compared to the wild-type H111 strain. It was further identified that Bcal3178 regulated target gene expression by directly binding to the promoter DNA regions. We also revealed that Bcal3178 was directly controlled by the AHL system regulator CepR. These results show that Bcal3178 is a new downstream component of the QS signaling network that modulates a subset of genes and functions coregulated by the AHL and BDSF QS systems in B. cenocepacia. Burkholderia cenocepacia is an important opportunistic pathogen in humans that utilizes the BDSF and AHL quorum-sensing (QS) systems to regulate biological functions and virulence. We demonstrated here that a new downstream regulator, Bcal3178 of the QS signaling network, controls biofilm formation and protease production. Bcal3178 is a LysR family transcriptional regulator modulated by both the BDSF and AHL QS systems. Furthermore, Bcal3178 controls many target genes, which are regulated by the QS systems in B. cenocepacia. Collectively, our findings depict a novel molecular mechanism with which QS systems regulate some target gene expression and biological functions by modulating the expression level of a LysR family transcriptional regulator in B. cenocepacia.
Topics: Bacterial Proteins; Biofilms; Burkholderia cenocepacia; Gene Expression Regulation, Bacterial; Mutation; Peptide Hydrolases; Phenotype; Quorum Sensing; Transcription Factors
PubMed: 33811025
DOI: 10.1128/AEM.00202-21 -
Scientific Reports Aug 2021Bioleaching of metal sulfide ores involves acidophilic microbes that catalyze the chemical dissolution of the metal sulfide bond that is enhanced by attached and...
Bioleaching of metal sulfide ores involves acidophilic microbes that catalyze the chemical dissolution of the metal sulfide bond that is enhanced by attached and planktonic cell mediated oxidation of iron(II)-ions and inorganic sulfur compounds. Leptospirillum spp. often predominate in sulfide mineral-containing environments, including bioheaps for copper recovery from chalcopyrite, as they are effective primary mineral colonizers and oxidize iron(II)-ions efficiently. In this study, we demonstrated a functional diffusible signal factor interspecies quorum sensing signaling mechanism in Leptospirillum ferriphilum and Leptospirillum ferrooxidans that produces (Z)-11-methyl-2-dodecenoic acid when grown with pyrite as energy source. In addition, pure diffusible signal factor and extracts from supernatants of pyrite grown Leptospirillum spp. inhibited biological iron oxidation in various species, and that pyrite grown Leptospirillum cells were less affected than iron grown cells to self inhibition. Finally, transcriptional analyses for the inhibition of iron-grown L. ferriphilum cells due to diffusible signal factor was compared with the response to exposure of cells to N- acyl-homoserine-lactone type quorum sensing signal compounds. The data suggested that Leptospirillum spp. diffusible signal factor production is a strategy for niche protection and defense against other microbes and it is proposed that this may be exploited to inhibit unwanted acidophile species.
PubMed: 34381075
DOI: 10.1038/s41598-021-95324-9 -
Proceedings of the National Academy of... Sep 2020Many bacteria cycle between sessile and motile forms in which they must sense and respond to internal and external signals to coordinate appropriate physiology....
Many bacteria cycle between sessile and motile forms in which they must sense and respond to internal and external signals to coordinate appropriate physiology. Maintaining fitness requires genetic networks that have been honed in variable environments to integrate these signals. The identity of the major regulators and how their control mechanisms evolved remain largely unknown in most organisms. During four different evolution experiments with the opportunist betaproteobacterium in a biofilm model, mutations were most frequently selected in the conserved gene RpfR uniquely integrates two major signaling systems-quorum sensing and the motile-sessile switch mediated by cyclic-di-GMP-by two domains that sense, respond to, and control the synthesis of the autoinducer cis-2-dodecenoic acid (BDSF). The BDSF response in turn regulates the activity of diguanylate cyclase and phosphodiesterase domains acting on cyclic-di-GMP. Parallel adaptive substitutions evolved in each of these domains to produce unique life history strategies by regulating cyclic-di-GMP levels, global transcriptional responses, biofilm production, and polysaccharide composition. These phenotypes translated into distinct ecology and biofilm structures that enabled mutants to coexist and produce more biomass than expected from their constituents grown alone. This study shows that when bacterial populations are selected in environments challenging the limits of their plasticity, the evolved mutations not only alter genes at the nexus of signaling networks but also reveal the scope of their regulatory functions.
Topics: Bacterial Proteins; Biofilms; Burkholderia cenocepacia; Cyclic GMP; Directed Molecular Evolution; Gene Expression Regulation, Bacterial; Mutation; Phenotype; Quorum Sensing; Signal Transduction; Virulence
PubMed: 32817433
DOI: 10.1073/pnas.2008540117 -
Life Science Alliance Oct 2020Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS...
Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (-11-methyl-dodecenoic acid) produced by pv. can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in , mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of , with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
Topics: Arabidopsis; Arabidopsis Proteins; Cell Membrane; Clathrin; Flagellin; Immunity, Innate; Plant Diseases; Plant Immunity; Protein Kinases; Quorum Sensing; Signal Transduction; Sterols; Xanthomonas campestris
PubMed: 32788227
DOI: 10.26508/lsa.202000720 -
Cell Reports May 2024Quorum sensing (QS) is a cell-to-cell communication mechanism mediated by small diffusible signaling molecules. Previous studies showed that RpfR controls Burkholderia...
Quorum sensing (QS) is a cell-to-cell communication mechanism mediated by small diffusible signaling molecules. Previous studies showed that RpfR controls Burkholderia cenocepacia virulence as a cis-2-dodecenoic acid (BDSF) QS signal receptor. Here, we report that the fatty acyl-CoA ligase DsfR (BCAM2136), which efficiently catalyzes in vitro synthesis of lauryl-CoA and oleoyl-CoA from lauric acid and oleic acid, respectively, acts as a global transcriptional regulator to control B. cenocepacia virulence by sensing BDSF. We show that BDSF binds to DsfR with high affinity and enhances the binding of DsfR to the promoter DNA regions of target genes. Furthermore, we demonstrate that the homolog of DsfR in B. lata, RS02960, binds to the target gene promoter, and perception of BDSF enhances the binding activity of RS02960. Together, these results provide insights into the evolved unusual functions of DsfR that control bacterial virulence as a response regulator of QS signal.
Topics: Quorum Sensing; Burkholderia cenocepacia; Virulence; Bacterial Proteins; Coenzyme A Ligases; Gene Expression Regulation, Bacterial; Promoter Regions, Genetic; Animals; Signal Transduction; Fatty Acids, Monounsaturated; Mice; Protein Binding; Lauric Acids
PubMed: 38748879
DOI: 10.1016/j.celrep.2024.114223 -
Microbial Ecology Feb 2021Bdellovibrio bacteriovorus 109J is a predatory bacterium which lives by predating on other Gram-negative bacteria to obtain the nutrients it needs for replication and...
Bdellovibrio bacteriovorus 109J is a predatory bacterium which lives by predating on other Gram-negative bacteria to obtain the nutrients it needs for replication and survival. Here, we evaluated the effects two classes of bacterial signaling molecules (acyl homoserine lactones (AHLs) and diffusible signaling factor (DSF)) have on B. bacteriovorus 109J behavior and viability. While AHLs had a non-significant impact on predation rates, DSF considerably delayed predation and bdelloplast lysis. Subsequent experiments showed that 50 μM DSF also reduced the motility of attack-phase B. bacteriovorus 109J cells by 50% (38.2 ± 14.9 vs. 17 ± 8.9 μm/s). Transcriptomic analyses found that DSF caused genome-wide changes in B. bacteriovorus 109J gene expression patterns during both the attack and intraperiplasmic phases, including the significant downregulation of the flagellum assembly genes and numerous serine protease genes. While the former accounts for the reduced speeds observed, the latter was confirmed experimentally with 50 μM DSF completely blocking protease secretion from attack-phase cells. Additional experiments found that 30% of the total cellular ATP was released into the supernatant when B. bacteriovorus 109J was exposed to 200 μM DSF, implying that this QS molecule negatively impacts membrane integrity.
Topics: 4-Butyrolactone; Antibiosis; Bdellovibrio bacteriovorus; Cell Membrane; Fatty Acids, Monounsaturated; Flagella; Quorum Sensing; Serine Proteases; Stress, Physiological; Transcriptome
PubMed: 32892232
DOI: 10.1007/s00248-020-01585-8 -
Reproductive Toxicology (Elmsford, N.Y.) Apr 2024Apilarnil, a bee-derived product originating from drone larvae, offers a range of advantageous properties for both humans and animals. It functions as an antioxidant,...
Apilarnil, a bee-derived product originating from drone larvae, offers a range of advantageous properties for both humans and animals. It functions as an antioxidant, provides neuroprotection, boosts fertility, and has antiviral capabilities. Additionally, it is a provider of androgenic hormones. These beneficial functions are supported by its chemical composition, which comprises mineral salts, vitamins, carbs, lipids, hormones, and amino acids. The current study aimed to evaluate the ameliorative effect of apilarnil against Bisphenol A (BPA)-induced testicular toxicity in male adult rats. Forty-eight Wistar albino rats were randomly classified into six groups. The first, second, and third received olive oil, BPA at a dose of 50 mg/kg body weight (bwt), and apilarnil at a dose of 0.6 g/kg bwt, respectively. The fourth, fifth, and sixth groups received apilarnil with, before, or after BPA administration, respectively. Phytochemical analysis using included linear ion trap-ultra-performance liquid chromatography-tandem mass spectrometry (LTQ-UPLC-MS/MS) and global natural products social molecular networking (GNPS) revealed the presence of lysine, 10-hydroxy-(E)-2-dodecenoic acid, apigenin7-glucoside, testosterone, progesterone, and campesterol. BPA administration decreased serum level of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, glutathione (GSH) concentration, total sperm count, motility, and vitality. Additionally, BPA increased sperm abnormalities, malondialdehyde concentration (MDA), and decreased proliferating cell nuclear antigen (PCNA) expression. The treatment with apilarnil ameliorated BPA reproductive toxicity in rats which was indicated by increased serum testosterone levels, normalized serum levels of FSH and LH, and concentration of MDA and GSH activity. Moreover, apilarnil improved sperm count, motility, morphology, and PCNA expression. Apilarnil was found to enhance reproductive hormones, MDA levels, antioxidant activity, and PCNA expression.
Topics: Adult; Animals; Humans; Male; Rats; Antioxidants; Benzhydryl Compounds; Biological Products; Chromatography, Liquid; Follicle Stimulating Hormone; Glutathione; Luteinizing Hormone; Oxidative Stress; Phenols; Proliferating Cell Nuclear Antigen; Rats, Wistar; Sperm Count; Tandem Mass Spectrometry; Testis; Testosterone
PubMed: 38484946
DOI: 10.1016/j.reprotox.2024.108570 -
The Journal of Infectious Diseases Mar 2024Bone infections from Staphylococcus aureus are notoriously difficult to treat and have high recurrence rates. Local antibiotic delivery systems hold the potential to...
BACKGROUND
Bone infections from Staphylococcus aureus are notoriously difficult to treat and have high recurrence rates. Local antibiotic delivery systems hold the potential to achieve high in situ antibiotic concentrations, which are otherwise challenging to achieve via systemic administration. Existing solutions have been shown to confer suboptimal drug release and distribution. Here we present and evaluate an injectable in situ-forming depot system termed CarboCell. The CarboCell technology provides sustained and tuneable release of local high-dose antibiotics.
METHODS
CarboCell formulations of levofloxacin or clindamycin with or without antimicrobial adjuvants cis-2-decenoic acid or cis-11-methyl-2-dodecenoic acid were tested in experimental rodent and porcine implant-associated osteomyelitis models. In the porcine models, debridement and treatment with CarboCell-formulated antibiotics was carried out without systemic antibiotic administration. The bacterial burden was determined by quantitative bacteriology.
RESULTS
CarboCell formulations eliminated S. aureus in infected implant rat models. In the translational implant-associated pig model, surgical debridement, and injection of clindamycin-releasing CarboCell formulations resulted in pathogen-free bone tissues and implants in 9/12, and full eradication in 5/12 pigs.
CONCLUSIONS
Sustained release of antimicrobial agents mediated by the CarboCell technology demonstrated promising therapeutic efficacy in challenging translational models and may be beneficial in combination with the current standard of care.
PubMed: 38537273
DOI: 10.1093/infdis/jiae139