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FEBS Letters Jan 2022Global transcriptional regulator downstream RpfR (GtrR) is a key downstream regulator for quorum-sensing signaling molecule cis-2-dodecenoic acid (BDSF). As a bacterial...
Global transcriptional regulator downstream RpfR (GtrR) is a key downstream regulator for quorum-sensing signaling molecule cis-2-dodecenoic acid (BDSF). As a bacterial enhancer-binding protein (bEBP), GtrR is composed of an N-terminal receiver domain, a central ATPases associated with diverse cellular activities (AAA+) ATPase σ -interaction domain, and a C-terminal helix-turn-helix DNA-binding domain. In this work, we solved its AAA+ ATPase domain in both apo and GTP-bound forms. The structure revealed how GtrR specifically recognizes GTP. In addition, we also revealed that GtrR has moderate GTPase activity in vitro in the absence of its activation signal. Finally, we found the residues K170, D236, R311, and R357 in GtrR that are crucial to its biological function, any single mutation leading to completely abolishing GtrR activity.
Topics: Burkholderia cenocepacia
PubMed: 34837384
DOI: 10.1002/1873-3468.14244 -
Journal of Chemical Ecology Dec 2021Synthetic pheromones have been used for pest control over several decades. The conventional synthesis of di-unsaturated pheromone compounds is usually complex and...
Synthetic pheromones have been used for pest control over several decades. The conventional synthesis of di-unsaturated pheromone compounds is usually complex and costly. Camelina (Camelina sativa) has emerged as an ideal, non-food biotech oilseed platform for production of oils with modified fatty acid compositions. We used Camelina as a plant factory to produce mono- and di-unsaturated C chain length moth sex pheromone precursors, (E)-9-dodecenoic acid and (E,E)-8,10-dodecadienoic acid, by introducing a fatty acyl-ACP thioesterase FatB gene UcTE from California bay laurel (Umbellularia californica) and a bifunctional ∆9 desaturase gene Cpo_CPRQ from the codling moth, Cydia pomonella. Different transgene combinations were investigated for increasing pheromone precursor yield. The most productive Camelina line was engineered with a vector that contained one copy of UcTE and the viral suppressor protein encoding P19 transgenes and three copies of Cpo_CPRQ transgene. The T generation of this line produced 9.4% of (E)-9-dodecenoic acid and 5.5% of (E,E)-8,10-dodecadienoic acid of the total fatty acids, and seeds were selected to advance top-performing lines to homozygosity. In the T generation, production levels of (E)-9-dodecenoic acid and (E,E)-8,10-dodecadienoic acid remained stable. The diene acid together with other seed fatty acids were converted into corresponding alcohols, and the bioactivity of the plant-derived codlemone was confirmed by GC-EAD and a flight tunnel assay. Trapping in orchards and home gardens confirmed significant and specific attraction of C. pomonella males to the plant-derived codlemone.
Topics: Animals; Brassicaceae; Dodecanol; Metabolic Engineering; Moths; Sex Attractants
PubMed: 34762210
DOI: 10.1007/s10886-021-01316-4 -
Molecular Plant Pathology Jan 2022The Xanthomonas group of phytopathogens communicate with a fatty acid-like cell-cell signalling molecule, cis-11-2-methyl-dodecenoic acid, also known as diffusible...
The Xanthomonas group of phytopathogens communicate with a fatty acid-like cell-cell signalling molecule, cis-11-2-methyl-dodecenoic acid, also known as diffusible signal factor (DSF). In the pathogen of rice, Xanthomonas oryzae pv. oryzae, DSF is involved in the regulation of several virulence-associated functions, including production and secretion of several cell wall hydrolysing type II secretion effectors. To understand the role of DSF in the secretion of type II effectors, we characterized DSF synthase-deficient (rpfF) and DSF-deficient, type II secretion (xpsE) double mutants. Mutant analysis by expression analysis, secretion assay, fatty acid analysis, and physiological studies indicated that rpfF mutants exhibit hypersecretion of several type II effectors due to a perturbed membrane and DSF is required for maintaining membrane integrity. The rpfF mutants exhibited significantly higher uptake of 1-N-phenylnapthylamine and ethidium bromide, and up-regulation of rpoE (σ ). Increasing the osmolarity of the medium could rescue the hypersecretion phenotype of the rpfF mutant. The rpfF mutant exhibited highly reduced virulence. We report for the first time that in X. oryzae pv. oryzae RpfF is involved in the maintenance of membrane integrity by playing a regulatory role in the fatty acid synthesis pathway.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Mutation; Plant Diseases; Virulence; Xanthomonas
PubMed: 34704368
DOI: 10.1111/mpp.13148 -
Microbiology Spectrum Oct 2021Asthma is a multifactorial disorder, and microbial dysbiosis enhances lung inflammation and asthma-related symptoms. Probiotics have shown anti-inflammatory effects and... (Randomized Controlled Trial)
Randomized Controlled Trial
Asthma is a multifactorial disorder, and microbial dysbiosis enhances lung inflammation and asthma-related symptoms. Probiotics have shown anti-inflammatory effects and could regulate the gut-lung axis. Thus, a 3-month randomized, double-blind, and placebo-controlled human trial was performed to investigate the adjunctive efficacy of probiotics in managing asthma. Fifty-five asthmatic patients were randomly assigned to a probiotic group ( = 29; received Bifidobacterium lactis Probio-M8 powder and Symbicort Turbuhaler) and a placebo group ( = 26; received placebo and Symbicort Turbuhaler), and all 55 subjects provided details of their clinical history and demographic data. However, only 31 patients donated a complete set of fecal and blood samples at all three time points for further analysis. Compared with those of the placebo group, co-administering Probio-M8 with Symbicort Turbuhaler significantly decreased the fractional exhaled nitric oxide level at day 30 (= 0.049) and improved the asthma control test score at the end of the intervention (= 0.023). More importantly, the level of alveolar nitric oxide concentration decreased significantly among the probiotic receivers at day 30 (= 0.038), and the symptom relief effect was even more obvious at day 90 (= 0.001). Probiotic co-administration increased the resilience of the gut microbiome, which was reflected by only minor fluctuations in the gut microbiome diversity (> 0.05, probiotic receivers; < 0.05, placebo receivers). Additionally, the probiotic receivers showed significantly changes in some species-level genome bins (SGBs), namely, increases in potentially beneficial species Bifidobacterium animalis, Bifidobacterium longum, and sp. CAG and decreases in Parabacteroides distasonis and (< 0.05). Compared with that of the placebo group, the gut metabolic potential of probiotic receivers exhibited increased levels of predicted microbial bioactive metabolites (linoleoyl ethanolamide, adrenergic acid, erythronic acid) and serum metabolites (5-dodecenoic acid, tryptophan, sphingomyelin) during/after intervention. Collectively, our results suggested that co-administering Probio-M8 synergized with conventional therapy to alleviate diseases associated with the gut-lung axis, like asthma, possibly via activating multiple anti-inflammatory pathways. The human gut microbiota has a potential effect on the pathogenesis of asthma and is closely related to the disease phenotype. Our trial has demonstrated that co-administering Probio-M8 synergized with conventional therapy to alleviate asthma symptoms. The findings of the present study provide new insights into the pathogenesis and treatment of asthma, mechanisms of novel therapeutic strategies, and application of probiotics-based therapy.
Topics: Adolescent; Adult; Aged; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Asthma; Bifidobacterium animalis; Budesonide, Formoterol Fumarate Drug Combination; Double-Blind Method; Dysbiosis; Female; Gastrointestinal Microbiome; Humans; Lung; Male; Middle Aged; Nitric Oxide; Placebos; Probiotics; Young Adult
PubMed: 34612663
DOI: 10.1128/Spectrum.00859-21 -
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 -
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 -
Microorganisms Mar 2021The cultivation of the cellulolytic bacterium, , can have cost-effective cellulosic biomass utilizations, such as consolidated bioprocessing, simultaneous biological...
The cultivation of the cellulolytic bacterium, , can have cost-effective cellulosic biomass utilizations, such as consolidated bioprocessing, simultaneous biological enzyme production and saccharification. However, these processes require a longer cultivation term of approximately 1 week. We demonstrate that constituents of the membrane vesicle fraction significantly promoted the growth rate of . Similarly, cell-free broth was able to increase growth rate, while several single-gene deletion mutants, e.g., , , , , , decreased the growth stimulation ability. Metabolome analysis revealed signal compounds for cell-cell communication in the membrane vesicle fraction (ethyl 2-decenoate, ethyl 4-decenoate, and 2-dodecenoic acid) and broth (nicotinamide, indole-3-carboxaldehyde, urocanic acid, nopaline, and 6-paradol). These findings suggest that the constituents in membrane vesicles from and could promote growth, leading to improved efficiency of cellulosic biomass utilization.
PubMed: 33805707
DOI: 10.3390/microorganisms9030593 -
Journal of Chemical Ecology Mar 2021The European grapevine moth, Lobesia botrana, uses (E,Z)-7,9-dodecadienyl acetate as its major sex pheromone component. Through in vivo labeling experiments we...
Biosynthesis of the Sex Pheromone Component (E,Z)-7,9-Dodecadienyl Acetate in the European Grapevine Moth, Lobesia botrana, Involving ∆11 Desaturation and an Elusive ∆7 Desaturase.
The European grapevine moth, Lobesia botrana, uses (E,Z)-7,9-dodecadienyl acetate as its major sex pheromone component. Through in vivo labeling experiments we demonstrated that the doubly unsaturated pheromone component is produced by ∆11 desaturation of tetradecanoic acid, followed by chain shortening of (Z)-11-tetradecenoic acid to (Z)-9-dodecenoic acid, and subsequently introduction of the second double bond by an unknown ∆7 desaturase, before final reduction and acetylation. By sequencing and analyzing the transcriptome of female pheromone glands of L. botrana, we obtained 41 candidate genes that may be involved in sex pheromone production, including the genes encoding 17 fatty acyl desaturases, 13 fatty acyl reductases, 1 fatty acid synthase, 3 acyl-CoA oxidases, 1 acetyl-CoA carboxylase, 4 fatty acid transport proteins and 2 acyl-CoA binding proteins. A functional assay of desaturase and acyl-CoA oxidase gene candidates in yeast and insect cell (Sf9) heterologous expression systems revealed that Lbo_PPTQ encodes a ∆11 desaturase producing (Z)-11-tetradecenoic acid from tetradecanoic acid. Further, Lbo_31670 and Lbo_49602 encode two acyl-CoA oxidases that may produce (Z)-9-dodecenoic acid by chain shortening (Z)-11-tetradecenoic acid. The gene encoding the enzyme introducing the E7 double bond into (Z)-9-dodecenoic acid remains elusive even though we assayed 17 candidate desaturases in the two heterologous systems.
Topics: Acetyl-CoA Carboxylase; Amino Acid Sequence; Animals; Dodecanol; Fatty Acid Desaturases; Fatty Acid Synthases; Fatty Acid Transport Proteins; Female; Gas Chromatography-Mass Spectrometry; Moths; Myristic Acid; Oxidoreductases; Saccharomyces cerevisiae; Sex Attractants; Sf9 Cells; Transcriptome
PubMed: 33779878
DOI: 10.1007/s10886-021-01252-3 -
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