Comparative study of different dosages of grain-sized moxibustion on uterine artery blood flow in patients with cold and dampness primary dysmenorrhea. / ä¸åŒå‰‚é‡éº¦ç²’ç¸å¯¹å¯’æ¹¿å‡æ»žåž‹åŽŸå‘æ€§ç—›ç»æ‚£è€ å­å®«åŠ¨è„‰è¡€æµå½±å“çš„æ¯”è¾ƒç ”ç©¶.

OBJECTIVES: To observe the differences in the effects of different dosages of grain-sized moxibustion on uterine artery blood flow in patients with cold and dampness primary dysmenorrhea (PD). METHODS: A total of 60 patients with PD were randomly divided into 3 groups with 20 cases in each group. Acupoints Sanyinjiao (SP6), Diji (SP8) and Xuehai (SP10) were selected in all the 3 groups, and different dosages of grain-sized moxibustion were used (3 moxa cones, 6 moxa cones, 9 moxa cones) respectively. Treatment started 7 days before menstruation for 3 times, lasting for a total of 3 menstrual cycles. The values of uterine artery blood flow parameters including pulsatility index (PI), resistance index (RI), and systolic/diastolic ratio (S/D) were recorded before and after treatment. The visual analog scale (VAS) score and cox menstrual symptom scale (CMSS) score (including severity ［CMSS-S］ and time of duration ［CMSS-T］) were evaluated before treatment, at the end of each menstrual cycle, and one menstrual cycle after treatment. RESULTS: The values of uterine artery blood flow parameters (PI, RI, S/D) after treatment in the 9 moxa cones group were lower than those before treatment, as well as lower than those in the 3 and 6 moxa cones groups after treatment (P<0.05). The VAS scores of the 3 moxa cones group were lower than those before treatment in the first and second cycle (P<0.05). The VAS scores of the 6 and 9 moxa cones groups were lower than those before treatment at each observation point (P<0.05), and were lower than those of the 3 moxa cones group in the third cycle of treatment and follow-up period (P<0.05). And the VAS score of the 9 moxa cones group was lower than that of the 6 moxa cones group during the follow-up period (P<0.05). Compared with the scores before treatment, the CMSS-T scores at each observation point after treatment were lower in the 9 moxa cones group (P<0.05)；the CMSS-T scores in the second and third cycle after treatment, and follow-up period were lower in the 6 moxa cones group (P<0.05), with the CMSS-S scores in the second and third cycle after treatment, and follow-up period lower in the 6 and 9 moxa cones groups (P<0.05). The CMSS-T and CMSS-S scores of the 6 and 9 moxa cones groups were lower than those of the 3 moxa cones group in the third cycle and follow-up period (P<0.05). The CMSS-T and CMSS-S scores of the 9 moxa cones group were lower than those of the 6 moxa cones group during the follow-up period (P<0.05). CONCLUSIONS: Grain-Sized moxibustion has dose-effect relationship in the treatment of PD. Compared with 3 and 6 moxa cones groups, 9 moxa cones group has advantages in improving uterine artery blood flow parameters and alleviating dysmenorrhea symptoms in PD patients.

[The skin surface microcirculation of conception vessel, governor vessel and thoroughfare vessel in patients with primary dysmenorrhea].

OBJECTIVE: To observe the skin surface microcirculation of acupoints of conception vessel, governor vessel and thoroughfare vessel in patients with primary dysmenorrhea using laser speckle contrast imaging (LSCI), and provide acupoint selection basis of acupuncture-moxibustion for primary dysmenorrhea. METHODS: Ninety-nine healthy female college students with regular menstrual cycles (normal group) and 94 female college students with primary dysmenorrhea (dysmenorrhea group) were recruited. Before menstrual period, on the first day of menstruation, and on the third day after menstruation, LSCI was used to observe the surface microcirculation at the abdominal acupoints of conception vessel, i. e. Yinjiao (CV 7), Qihai (CV 6), Shimen (CV 5), Guanyuan (CV 4), Zhongji (CV 3) and Qugou (CV 2), acupoints of thoroughfare vessel, i. e. Huangshu (KI 16), Zhongzhu (KI 15), Siman (KI 14), Qixue (KI 13), Dahe (KI 12), Henggu (KI 11) and acupoints of lumbosacral region of governor vessel, i. e. Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3), Yaoshu (GV 2) as well as two non-acupoints. RESULTS: Before menstrual period, there was no significant difference in the surface blood perfusion of the acupoints between the dysmenorrhea group and the normal group (P>0.05). On the first day of menstruation, the surface blood perfusion of Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3) and right Huangshu (KI 16) in the dysmenorrhea group was higher than that in the normal group (P<0.05, P<0.01). On the third day after menstruation, the surface blood perfusion of the right Henggu (KI 11) in the dysmenorrhea group was lower than that in the normal group (P<0.05). CONCLUSION: In patients with primary dysmenorrhea, on the first day of menstruation, the surface blood perfusion of Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3) of governor vessel, and the right Huangshu (KI 16) of thoroughfare vessel is increased, while on the third day after menstruation, the surface blood perfusion of the right Henggu (KI 11) of thoroughfare vessel is decreased. These findings might provide a basis for acupoint selection in the acupuncture-moxibustion treatment of primary dysmenorrhea.

The skin surface microcirculation of conception vessel, governor vessel and thoroughfare vessel in patients with primary dysmenorrhea / 中国针灸

OBJECTIVE@#To observe the skin surface microcirculation of acupoints of conception vessel, governor vessel and thoroughfare vessel in patients with primary dysmenorrhea using laser speckle contrast imaging (LSCI), and provide acupoint selection basis of acupuncture-moxibustion for primary dysmenorrhea.@*METHODS@#Ninety-nine healthy female college students with regular menstrual cycles (normal group) and 94 female college students with primary dysmenorrhea (dysmenorrhea group) were recruited. Before menstrual period, on the first day of menstruation, and on the third day after menstruation, LSCI was used to observe the surface microcirculation at the abdominal acupoints of conception vessel, i. e. Yinjiao (CV 7), Qihai (CV 6), Shimen (CV 5), Guanyuan (CV 4), Zhongji (CV 3) and Qugou (CV 2), acupoints of thoroughfare vessel, i. e. Huangshu (KI 16), Zhongzhu (KI 15), Siman (KI 14), Qixue (KI 13), Dahe (KI 12), Henggu (KI 11) and acupoints of lumbosacral region of governor vessel, i. e. Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3), Yaoshu (GV 2) as well as two non-acupoints.@*RESULTS@#Before menstrual period, there was no significant difference in the surface blood perfusion of the acupoints between the dysmenorrhea group and the normal group (P>0.05). On the first day of menstruation, the surface blood perfusion of Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3) and right Huangshu (KI 16) in the dysmenorrhea group was higher than that in the normal group (P<0.05, P<0.01). On the third day after menstruation, the surface blood perfusion of the right Henggu (KI 11) in the dysmenorrhea group was lower than that in the normal group (P<0.05).@*CONCLUSION@#In patients with primary dysmenorrhea, on the first day of menstruation, the surface blood perfusion of Xuanshu (GV 5), Mingmen (GV 4), Yaoyangguan (GV 3) of governor vessel, and the right Huangshu (KI 16) of thoroughfare vessel is increased, while on the third day after menstruation, the surface blood perfusion of the right Henggu (KI 11) of thoroughfare vessel is decreased. These findings might provide a basis for acupoint selection in the acupuncture-moxibustion treatment of primary dysmenorrhea.

Metabolomic and regular analysis reveal phytotoxic mechanisms of sterigmatocystin in Amaranthus retroflexus L.

Sterigmatocystin (STE) is a common hepatotoxic and nephrotoxic contaminant in cereals, however, its phytotoxicity and mechanisms are poorly understood. Here, the phytotoxic mechanisms of STE were investigated via the metabolomics of Amaranthus retroflexus L. A total of 140 and 113 differential metabolites were detected in the leaves and stems, respectively, among which amino acids, lipids, and phenolic compounds were significantly perturbed. Valine, leucine, isoleucine, and lysine biosynthesis were affected by STE. These metabolic responses revealed that STE might be toxic to plants by altering the plasma membrane and inducing oxidative damage, which was verified by measuring the relative electrical conductivity and quantification of reactive oxygen species. The elevated amino acids, as well as the decreased of D-sedoheptuiose-7-phosphate indicated increased proteolysis and carbohydrate metabolism restriction. Furthermore, the IAA level also decreased. This study provides a better understanding of the impacts of STE on the public health, environment and food security.

2E,4E-Decadienoic Acid, a Novel Anti-Oomycete Agent from Coculture of Bacillus subtilis and Trichoderma asperellum.

Phytophthora nicotianae is an oomycete pathogen of global significance threatening many important crops. It is mainly controlled by chemosynthetic fungicides, which endangers ecosystem and human health; thus, there is an urgent need to explore alternatives for these fungicides. In this study, a new anti-oomycete aliphatic compound, 2E,4E-decadienoic acid (DDA), was obtained through coculture of Bacillus subtilis Tpb55 and Trichoderma asperellum HG1. Both in vitro and in vivo tests showed that DDA had a strong inhibitory effect against P. nicotianae. In addition, rhizosphere microbiome analysis showed that DDA reduced the relative abundance of Oomycota in rhizosphere soil. Transcriptome sequencing (RNA-Seq) analysis revealed that treatment of P. nicotianae with DDA resulted in significant downregulation of antioxidant activity and energy metabolism, including antioxidant enzymes and ATP generation, and upregulation of membrane-destabilizing activity, such as phospholipid synthesis and degradation. The metabolomic analysis results implied that the pathways influenced by DDA were mainly related to carbohydrate metabolism, energy metabolism, and the cell membrane. The biophysical tests further indicated that DDA produced oxidative stress on P. nicotianae, inhibited antioxidant enzyme and ATPase activity, and increased cell membrane permeability. Overall, DDA exerts inhibitory activity by acting on multiple targets in P. nicotianae, especially on the cell membrane and mitochondria, and can therefore serve as a novel environment-friendly agent for controlling crop oomycete disease. IMPORTANCE P. nicotianae is an oomycete pathogen that is destructive to crops. Although some oomycete inhibitors have been used during crop production, most are harmful to the ecology and lead to pathogen resistance. Alternatively, medium-chain fatty acids have been reported to exhibit antimicrobial activity in the medical field in previous studies; however, their potential as biocontrol agents has rarely been evaluated. Our in vivo and in vitro analyses revealed that the medium-chain fatty acid 2E,4E-decadienoic acid (DDA) displayed specific inhibitory activity against oomycetes. Further analysis indicated that DDA may acted on multiple targets in P. nicotianae, especially on the cell membrane and mitochondria. Our findings highlight the potential of DDA in controlling oomycete diseases. In conclusion, these results provide insights regarding the future use of green and environment-friendly anti-oomycete natural products for the prevention and control of crop oomycete diseases.

Corrigendum: Microbubbles Ultrasonic Cavitation Regulates Tumor Interstitial Fluid Pressure and Enhances Sonodynamic Therapy.

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Microbubbles Ultrasonic Cavitation Regulates Tumor Interstitial Fluid Pressure and Enhances Sonodynamic Therapy.

Sonodynamic therapy (SDT) is a promising treatment method for solid tumors. However, the high interstitial fluid pressure (IFP) in tumor tissues limits the accumulation of sonosensitizers. In the present study, microbubbles ultrasonic cavitation was used to regulate the tumor's IFP and evaluate SDT effects. Rabbit VX2 tumor tissues were treated with microbubbles ultrasonic cavitation. The IFP of different tumor parts before and after cavitation was measured by the WIN method. The accumulation of the sonosensitizers hematoporphyrin monomethyl ether (HMME) in tumor tissues was observed using an ultramicro spectrophotometer and laser confocal microscope. Then, tumor-bearing rabbits were treated with SDT once a week for eight weeks and the therapeutic effect was evaluated. After microbubbles ultrasonic cavitation treatment, the tumor's IFP decreased and the HMME concentration increased. We concluded that microbubbles ultrasonic cavitation can increase HMME accumulation in rabbit VX2 tumors and increase SDT therapeutic effects.

Promoting the effect of microbubble-enhanced ultrasound on hyperthermia in rabbit liver.

PURPOSE: The heat-sink effect is one reason for the insufficient temperature increase in hyperthermia (HT) treatment for cancer. Microbubbles (MBs) nucleate inertial cavitation under therapeutic ultrasound (TUS) exposure, which form microbubble-enhanced ultrasound (MEUS), which results in blocking blood perfusion in the targeted liver tissues. This study aimed to determine if synergistic effects exist during HT in the liver when combined with MEUS. METHODS: Forty rabbits with surgically exposed livers were randomly divided into TUS + MB + HT, MB + HT, normal saline + HT, and MB + sham groups (n = 10 in each group). Liver perfusion was evaluated using contrast-enhanced ultrasound. The temperatures of the liver tissues were monitored using thermocouples. Pathological changes were determined by hematoxylin and eosin (H&E) staining. Serum hepatic transaminases were evaluated. RESULTS: MEUS pretreatment almost completely blocked the perfusion of targeted areas. The TUS + MB + HT and MB + HT groups showed significantly higher temperatures in treated areas than those in the other groups. However, the TUS + MB + HT group exhibited a more stable and regular increase in temperatures in the fitting curves compared with the MB + HT group. H&E staining revealed swelling hepatocytes, hemorrhage, and thrombosis in the portal area in the TUS + MB + HT group. CONCLUSION: MEUS reduced the blood perfusion in the targeted liver tissues, and, therefore, overcame the heat-sink effect during the HT procedure in rabbits. MEUS pretreatment might have the potential to enhance the therapeutic effect of HT.

Improving the Therapeutic Effect of Ultrasound Combined With Microbubbles on Muscular Tumor Xenografts With Appropriate Acoustic Pressure.

Ultrasound combined with microbubbles (USMB) is a promising antitumor therapy because of its capability to selectively disrupt tumor perfusion. However, the antitumor effects of repeated USMB treatments have yet to be clarified. In this study, we established a VX2 muscular tumor xenograft model in rabbits, and performed USMB treatments at five different peak negative acoustic pressure levels (1.0, 2.0, 3.0, 4.0, or 5.0 MPa) to determine the appropriate acoustic pressure. To investigate whether repeated USMB treatments could improve the antitumor effects, a group of tumor-bearing rabbits was subjected to one USMB treatment per day for three consecutive days for comparison with the single-treatment group. Contrast-enhanced ultrasonic imaging and histological analyses showed that at an acoustic pressure of 4.0 MPa, USMB treatment contributed to substantial cessation of tumor perfusion, resulting in severe damage to the tumor cells and microvessels without causing significant effects on the normal tissue. Further, the percentages of damaged area and apoptotic cells in the tumor were significantly higher, and the tumor growth inhibition effect was more obvious in the multiple-treatment group than in the single USMB treatment group. These findings indicate that with an appropriate acoustic pressure, the USMB treatment can selectively destroy tumor vessels in muscular tumor xenograft models. Moreover, the repeated treatments strategy can significantly improve the antitumor effect. Therefore, our results provide a foundation for the clinical application of USMB to treat solid tumors using a novel therapeutic strategy.

Antifungal Nafuredin and Epithiodiketopiperazine Derivatives From the Mangrove-Derived Fungus Trichoderma harzianum D13.

A new polyketide derivative, nafuredin C (1), a novel heterocyclic dipeptide, trichodermamide G (3), together with four known biogenetically related compounds nafuredin A (2), trichodermamide A (4), aspergillazin A (5), and peniisocoumarin H (6), were isolated from the mangrove-derived fungus Trichoderma harzianum D13. Their structures, including their absolute configurations, were determined by spectroscopic analysis and time-dependent density functional theory-electronic circular dichroism (ECD) calculations. Trichodermamide G was found to be a novel epithiodiketopiperazine derivative with an unprecedented cyclic system containing a sulfur bridge, and nafuredin C represented the third nafuredin derivative of these homologous compounds. The new compound nafuredin C exhibited obvious antifungal activity against Magnaporthe oryzae with a minimum inhibitory concentration (MIC) of 8.63 µM, which is on the same order of magnitude as the positive control carbendazim (MIC = 3.27 µM).

Effect of Ultrasound Combined With Microbubble Therapy on Interstitial Fluid Pressure and VX2 Tumor Structure in Rabbit.

Interstitial fluid pressure (IFP) in tumor tissue is significantly higher than that in normal tissue, which reduces the effectiveness of therapeutic drugs. There are several methods to decrease the IFP, such as normalizing blood vessel, decreasing hyaluronic acid and collagen fiber content in the extracellular matrix (ECM), and recovering lymphatic function. Reducing tumor IFP might be developed as a novel approach in cancer therapy. In this study, we aimed to elucidate the relationship between ultrasound combined with microbubble therapy and IFP, and the associated mechanism. VX2 tumor in rabbit was treated with ultrasound combined with microbubbles at different intensities. The IFP was measured using the wick-in-needle (WIN) method. The collagen and reticular fibers were stained by Masson and Gordon-Sweets, respectively. The results showed that low-frequency non-focus ultrasound combined with microbubbles therapy influences the IFP in tumor tissues; low-frequency non-focus ultrasound with low pressure increased the IFP, whereas middle-high pressure decreased the IFP. The results showed that the structure and content of collagen and reticular fibers in tumor tissue were rarely influenced by the treatment. Our study provides a novel approach of reduced IFP antitumor therapy.

The diagnostic role of circulating inflammation-based biomarker in gallbladder carcinoma.

AIM: To investigate the diagnostic roles of circulating inflammatory biomarkers in gallbladder carcinoma (GBC). PATIENTS & METHODS: Circulating inflammatory cell count, fibrinogen, albumin, carcinoembryonic antigen (CEA) and CA199 were measured, neutrophil-to-lymphocyte ratio (NLR), dNLR, PLR, LMR and Alb-to-fib (AFR) were calculated in 306 GBC patients, 306 healthy and 305 benign controls. The reciever operating characteristic curve was used to determine diagnostic accuracy of them. RESULTS: The area under curves of combined AFR, dNLR and lymphocyte were 0.943 and 0.985 for diagnosis of GBC from healthy and polyp controls, area under curve of combined AFR, CEA and CA199 was 0.90 for diagnosis of GBC from the cholecystitis patients. CONCLUSION: Circulating AFR combined with lymphocyte and dNLR or CEA and CA199 could effectively distinguish GBC from the healthy and benign controls.

Significance of combined preoperative serum Alb and dNLR for diagnosis of pancreatic cancer.

AIM: To investigate diagnostic value of preoperative inflammatory biomarkers in pancreatic cancer (PCC). MATERIALS & METHODS: Preoperative circulating Alb/Fib ratio, neutrophil/lymphocyte ratio (NLR), derived NLR (dNLR), platelet/lymphocyte ratio and lymphocyte/monocyte ratio were detected and calculated in 226 PCC individuals, 232 healthy controls and 142 additional cancer controls. Receiver-operating characteristic curve and area under the curve (AUC) were used to evaluate the diagnostic efficacy of PCC. RESULTS: Combined circulating dNLR and Alb could effectively improve the diagnosis of PCC (AUC = 0.931), single dNLR could distinguish early-stage PCC and the disease from healthy controls (AUC = 0.895) and additional cancer controls (AUC = 0.794). CONCLUSION: Circulating dNLR was an effective biomarker for diagnosis and identification of early-stage PCC. Combined dNLR and Alb could improve the diagnostic efficacy of the disease.

Palmitate induces fat accumulation by activating C/EBPß-mediated G0S2 expression in HepG2 cells.

AIM: To determine the role of G0/G1 switch gene 2 (G0S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation. METHODS: HepG2 cells were treated with palmitate, or palmitate in combination with CCAAT/enhancer binding protein (C/EBP)ß siRNA or G0S2 siRNA. The mRNA expression of C/EBPß, peroxisome proliferator-activated receptor (PPAR)γ and PPARγ target genes (G0S2, GPR81, GPR109A and Adipoq) was examined by qPCR. The protein expression of C/EBPß, PPARγ, and G0S2 was determined by Western blotting. Lipid accumulation was detected with Oil Red O staining and quantified by absorbance value of the extracted Oil Red O dye. Lipolysis was evaluated by measuring the amount of glycerol released into the medium. RESULTS: Palmitate caused a dose-dependent increase in lipid accumulation and a dose-dependent decrease in lipolysis in HepG2 cells. In addition, palmitate increased the mRNA expression of C/EBPß, PPARγ, and PPARγ target genes (G0S2, GPR81, GPR109A, and Adipoq) and the protein expression of C/EBPß, PPARγ, and G0S2 in a dose-dependent manner. Knockdown of C/EBPß decreased palmitate-induced PPARγ and its target genes (G0S2, GPR81, GPR109A, and Adipoq) mRNA expression and palmitate-induced PPARγ and G0S2 protein expression in HepG2 cells. Knockdown of C/EBPß also attenuated lipid accumulation and augmented lipolysis in palmitate-treated HepG2 cells. G0S2 knockdown attenuated lipid accumulation and augmented lipolysis, while G0S2 knockdown had no effects on the mRNA expression of C/EBPß, PPARγ, and PPARγ target genes (GPR81, GPR109A and Adipoq) in palmitate-treated HepG2 cells. CONCLUSION: Palmitate can induce lipid accumulation in HepG2 cells by activating C/EBPß-mediated G0S2 expression.

Characterization of a novel cyfluthrin-degrading bacterial strain Brevibacterium aureum and its biochemical degradation pathway.

Brevibacterium aureum DG-12, a new bacterial strain isolated from active sludge, was able to degrade and utilize cyfluthrin as a growth substrate in the mineral medium. Response surface methodology using central composite rotatable design of cultural conditions was successfully employed for optimization resulting in 88.6% degradation of cyfluthrin (50mgL(-1)) within 5days. The bacterium degraded cyfluthrin by cleavage of both the carboxylester linkage and diaryl bond to form 2,2,3,3-tetramethyl-cyclopropanemethanol, 4-fluoro-3-phenexy-benzoic acid, 3,5-dimethoxy phenol, and phenol, and subsequently transformed these compounds with a maximum specific degradation rate, half-saturation constant and inhibition constant of 1.0384day(-1), 20.4967mgL(-1), and 141.9013mgL(-1), respectively. A novel degradation pathway for cyfluthrin was proposed based on analysis of these metabolites. In addition, this strain was found capable of degrading a wide range of synthetic pyrethroid insecticides. Our results suggest that B. aureum DG-12 may be an ideal microorganism for bioremediation of the pyrethroid-contaminated environments.

The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa.

The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA-binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT-PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine-tune this virulence mechanism in response to environmental changes and nutrient sources.

A novel two-component system BqsS-BqsR modulates quorum sensing-dependent biofilm decay in Pseudomonas aeruginosa.

Pseudomonas aeruginosa can grow either as planktonic- or biofilm-form in response to environmental changes. Recent studies show that switching from biofilm to planktonic lifestyle requires rhamnolipids. Here we report the identification of a novel twocomponent system BqsS-BqsR that regulates biofilm decay in P. aeruginosa. BqsS is a multidomain sensor kinase and BqsR is an OmpR-like response regulator. Deletion of either bqsS or bqsR in P. aeruginosa mPAO1 resulted in a significant increase in biofilm formation. Time course analysis showed that the bqsS-bqsR mutants were defective in biofilm dispersal and in rhamnolipid production. Mutation of the BqsS-BqsR two-component system did not affect the biosynthesis of long chain quorum sensing (QS) signal N-3-oxo-dodecanoyl-homoserine lactone (3OC12HSL) but resulted in reduced production of the short chain QS signal N-butyryl-L-homoserine lactone (C4HSL) and the Pseudomonas quinolone signal (PQS). Exogenous addition of C4HSL, PQS or rhamnolipids to the bqsS mutant reduced the biofilm formation to the wild-type level. Evidence suggests that the BqsS-BqsR two-component system might promote conversion of anthranilate to PQS. Taken together, these results establish BqsS-BqsR as a novel two-component system that regulates biofilm decay in P. aeruginosa by modulating biosynthesis of QS signals and rhamnolipids.

Simulation on an optimal combustion control strategy for 3-D temperature distributions in tangentially pc-fired utility boiler furnaces.

The control of 3-D temperature distribution in a utility boiler furnace is essential for the safe, economic and clean operation of pc-fired furnace with multi-burner system. The development of the visualization of 3-D temperature distributions in pc-fired furnaces makes it possible for a new combustion control strategy directly with the furnace temperature as its goal to improve the control quality for the combustion processes. Studied in this paper is such a new strategy that the whole furnace is divided into several parts in the vertical direction, and the average temperature and its bias from the center in every cross section can be extracted from the visualization results of the 3-D temperature distributions. In the simulation stage, a computational fluid dynamics (CFD) code served to calculate the 3-D temperature distributions in a furnace, then a linear model was set up to relate the features of the temperature distributions with the input of the combustion processes, such as the flow rates of fuel and air fed into the furnaces through all the burners. The adaptive genetic algorithm was adopted to find the optimal combination of the whole input parameters which ensure to form an optimal 3-D temperature field in the furnace desired for the operation of boiler. Simulation results showed that the strategy could soon find the factors making the temperature distribution apart from the optimal state and give correct adjusting suggestions.

VqsM, a novel AraC-type global regulator of quorum-sensing signalling and virulence in Pseudomonas aeruginosa.

Human pathogen Pseudomonas aeruginosa uses quorum-sensing (QS) signalling systems to synchronize the production of virulence factors. There are two interrelated QS systems, las and rhl, in P. aeruginosa. In addition to this complexity, a number of transcriptional regulators were shown to have complicated interplays with las and rhl central QS components. Here, we describe a novel virulence and QS modulator (VqsM) that positively regulates the QS systems in P. aeruginosa. Mutation in vqsM resulted in much reduced production of N-acylhomoserine lactones (AHLs) and extracellular enzymes. Sequence analysis revealed that vqsM encodes a transcriptional regulator with an AraC-type helix-turn-helix DNA binding domain at the C-terminal of the peptide. Global gene expression profile analysis showed at least a total of 302 genes to be influenced, directly or indirectly, by VqsM. Among the 203 VqsM-promoted genes, 52.2% were known to be QS upregulated. Several genes encoding the key regulators implicated in QS, such as rhlR, rsaL, vqsR, mvfR, pprB and rpoS, and two AHL synthesis genes, lasI and rhlI, were suppressed in the vqsM mutant. Similar to the 'AHL-blind' phenotype of vqsR and pprB mutants, vqsM mutant did not respond to external addition of N-3-oxo-dodecanoyl-homoserine lactone signals. Moreover, overexpression of vqsR in vqsM mutant more or less restored the production of both AHL and virulence factors. The results demonstrate that VqsM, largely through modulation of vqsR expression, plays a vital role in regulation of QS signalling in P. aeruginosa.

The two-component response regulator PprB modulates quorum-sensing signal production and global gene expression in Pseudomonas aeruginosa.

The response regulator PprB and its cognate sensor PprA were recently reported as a two-component regulatory system that controls membrane permeability and antibiotic sensitivity of Pseudomonas aeruginosa. We found that a Tn5 insertion mutation in pprB caused a drastic reduction in virulence factor production and cell motility. A transcriptome analysis revealed that 175 genes were regulated by PprB. Among the 113 PprB-activated genes, 85.5% are known to be activated by N-3-oxo-dodecanoyl-homoserine lactone (OdDHL) and N-butanoyl-homoserine lactone (BHL). In particular, the expression of lasI, rhlI and rhlR, which encode key components of the las and rhl quorum-sensing (QS) systems, were significantly decreased in the pprB mutant. These data suggest that PprB might regulate QS signal production. Measurement of OdDHL and BHL in cultures of the mutant sustained this hypothesis. By using various OdDHL- or BHL-responsive QS reporter systems, including lasB-lacZ, lasI-lacZ and rsaL-lacZ, we found that the mutation in pprB resulted in a large decrease in the sensitivity of P. aeruginosa to exogenous OdDHL. However, there was no difference in sensitivity to BHL. Further analysis showed that the OdDHL influx was significantly reduced in the pprB mutant. We conclude that PprB is a novel QS modulator that positively regulates N-acylhomoserine lactone production probably by affecting the OdDHL signal influx and thereby influences global expression of the QS-dependent genes.