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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 -
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 -
Journal of Diabetes and Its... Feb 2021We aimed to investigate whether treatment with exenatide could ameliorate endothelial injury in patients with type 2 diabetes mellitus (T2DM), and to identify biomarkers...
AIMS
We aimed to investigate whether treatment with exenatide could ameliorate endothelial injury in patients with type 2 diabetes mellitus (T2DM), and to identify biomarkers for predicting amelioration of the endothelial injury induced by the treatment.
METHODS
Ninety-three patients with T2DM were recruited and treated with exenatide for 16 weeks. Enzyme-linked immunosorbent assays were performed at baseline and after the treatment to measure serum levels of endothelial injury markers, including soluble thrombomodulin (sTM). Patients were categorized as responders (n = 47) or non-responders (n = 46) based on median changes in their sTM levels. Serum levels of metabolites at baseline were measured with non-targeted liquid chromatography-mass spectrometry. The results obtained were evaluated with multivariate analysis.
RESULTS
Treatment with exenatide for 16 weeks resulted in reduced body weight and improved levels of fasting plasma glucose, 2-hour postprandial plasma glucose, and HbA1c in patients with T2DM (all P < 0.05). Compared with baseline, serum levels of endothelial injury markers including sTM were significantly lowered after the treatment. Metabolites presented at significantly different levels in responders versus non-responders were considered as biomarkers for a therapeutic response of sTM to the exenatide treatment. Among those identified, 4-hydroxyproline and 12-oxo-9(Z)-dodecenoic acid were found to correlate most closely with the exenatide-induced endothelial protection response. The specificity and sensitivity of the multi-metabolite signature model contained higher 4-hydroxyproline and lower 12-oxo-9(Z)-dodecenoic acid were 53.3% and 92.3%, respectively, and the area under receiver operating characteristic curve was 69.2% (P < 0.001).
CONCLUSIONS
Treatment with exenatide for 16 weeks ameliorates endothelial injury in patients with T2DM. Endothelial protection benefit from exenatide treatment was effectively predicted by the specific metabolomic combination of higher 4-hydroxyproline and lower 12-oxo-9(Z)-dodecenoic acid.
Topics: Biomarkers; Blood Glucose; Diabetes Mellitus, Type 2; Endothelium, Vascular; Exenatide; Glycated Hemoglobin; Humans; Hydroxyproline; Hypoglycemic Agents; Metabolomics
PubMed: 33293208
DOI: 10.1016/j.jdiacomp.2020.107797 -
Journal of Proteome Research Jan 2021A discovery-based lipid profiling study of serum samples from a cohort that included patients with clear cell renal cell carcinoma (ccRCC) stages I, II, III, and IV ( =...
A discovery-based lipid profiling study of serum samples from a cohort that included patients with clear cell renal cell carcinoma (ccRCC) stages I, II, III, and IV ( = 112) and controls ( = 52) was performed using ultraperformance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry and machine learning techniques. Multivariate models based on support vector machines and the LASSO variable selection method yielded two discriminant lipid panels for ccRCC detection and early diagnosis. A 16-lipid panel allowed discriminating ccRCC patients from controls with 95.7% accuracy in a training set under cross-validation and 77.1% accuracy in an independent test set. A second model trained to discriminate early (I and II) from late (III and IV) stage ccRCC yielded a panel of 26 compounds that classified stage I patients from an independent test set with 82.1% accuracy. Thirteen species, including cholic acid, undecylenic acid, lauric acid, LPC(16:0/0:0), and PC(18:2/18:2), identified with level 1 exhibited significantly lower levels in samples from ccRCC patients compared to controls. Moreover, 3α-hydroxy-5α-androstan-17-one 3-sulfate, -5-dodecenoic acid, arachidonic acid, -13-docosenoic acid, PI(16:0/18:1), PC(16:0/18:2), and PC(O-16:0/20:4) contributed to discriminate early from late ccRCC stage patients. The results are auspicious for early ccRCC diagnosis after validation of the panels in larger and different cohorts.
Topics: Biomarkers, Tumor; Carcinoma, Renal Cell; Early Diagnosis; Humans; Kidney Neoplasms; Lipidomics; Machine Learning; Mass Spectrometry
PubMed: 33207877
DOI: 10.1021/acs.jproteome.0c00663 -
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 -
Journal of Separation Science Oct 2020A simple, rapid, and cost-effective process for the separation of an active anticoagulant fraction from the aqueous fruit extract of Momordica charantia by using rice...
A simple, cost-effective, and rapid separation process for the isolation of anticoagulant active fraction from the fruit extract of Momordica charantia: Characterization of bioactive components and anticoagulant mechanism of active fraction in a mouse model.
A simple, rapid, and cost-effective process for the separation of an active anticoagulant fraction from the aqueous fruit extract of Momordica charantia by using rice husk as adsorbed is described. The in vitro anticoagulant activity of active anticoagulant fraction was comparable to commercial anticoagulants heparin and warfarin. Phytochemical analysis revealed the presence of alkaloids, flavonoids, and phytols in the active anticoagulant fraction, nevertheless; it was devoid of glycosides, triterpenoids, tannins, saponins, steroids, and carbohydrates. By gas chromatography with mass spectrometry analysis, decanoic acid, 1,2,3-propanetriyl ester (22.3%), dodecanoic acid, 1,2,3-propanetriyl ester-d5 (17.3%), dodecenoic acid, 1,2,3-propanetriyl ester (12.5%), and 4-B-methylandrostane 2,3-diol-1,17-dione (11.4%) were identified as the most abundant constituents of active anticoagulant fraction. Presence of αβ-fibrinogenase enzyme was identified by biochemical assay but not by liquid chromatography with tandem mass spectrometry analysis suggesting presence of a novel protease enzyme in this fraction. The active anticoagulant fraction demonstrated biding to fibrinogen but not to thrombin or Factor Xa, inhibited the collagen/ADP-induced mammalian platelet aggregation, showed in vitro thrombolytic activity, noncytotoxic to mammalian cells, showed in vivo plasma defibrinogenation and anticoagulant activities, and inhibited k-carrageen-induced thrombus formation in the tails of mice. Therefore, active anticoagulant fraction (an herbal drug) may find therapeutic application for the prevention and/or treatment of hyperfibrinogenemia/thrombosis-associated cardiovascular disorders.
Topics: Animals; Anticoagulants; Chondrus; Disease Models, Animal; Fruit; Humans; Mice; Momordica charantia; Plant Extracts; Thrombosis
PubMed: 32833304
DOI: 10.1002/jssc.202000452 -
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