Journal articles: 'Rsm pathway'

1

Singh, Jagmohan, and Satish Rattan. "Role of PKC and RhoA/ROCK pathways in the spontaneous phasic activity in the rectal smooth muscle." American Journal of Physiology-Gastrointestinal and Liver Physiology 304, no. 8 (April 15, 2013): G723—G731. http://dx.doi.org/10.1152/ajpgi.00473.2012.

Full text

Abstract:

The role of PKC and RhoA/ROCK pathways in the phasic activities in the rectal smooth muscles (RSM) in the basal state is not known. We examined this issue by determining the effects of PKC inhibitors (calphostin C and Gö-6850) and a ROCK inhibitor (Y-27632) on the slow-rate (∼3/min) and fast-rate (∼25/min) phasic activities. We also examined the corresponding signal transduction cascades and the PKC and ROCK enzymatic activities in the RSM in the basal state. PKC inhibition with calphostin C and Gö-6850 (10−5 M) caused a significant decrease (∼25%) in slow-rate (but not fast-rate) phasic activity (monitored by frequency and amplitude of contractions) of the RSM. Conversely, ROCK inhibition with Y-27632 (10−5 M) caused a significant decrease not only in slow-rate, but also fast-rate, phasic activity caused by ROCK inhibition in the RSM. Western blot analysis revealed that the PKC inhibition-induced decrease in RSM phasic activity was associated with decreases in PKCα translocation, phosphorylated (Thr38) PKC-potentiated inhibitor (CPI-17), and phosphorylated (Thr18/Ser19) 20-kDa myosin regulatory light chain. Conversely, decreases in the phasic activity in the RSM by ROCK inhibition were accompanied by the additional decrease in phosphorylated (Thr696) myosin phosphatase target subunit 1. Data show that while PKC and RhoA/ROCK pathways play a significant role in slow-rate high-amplitude spontaneous phasic activity, only the RhoA/ROCK pathway primarily mediates fast-rate low-amplitude phasic activity, in the RSM. Such knowledge is important in the understanding of the pathophysiology of large intestinal motility disorders. Relative contributions of the PKC vs. the RhoA/ROCK pathway in the phasic activity remain to be determined.

APA, Harvard, Vancouver, ISO, and other styles

2

Fang, Yanyan, Jian Liu, Ling Xin, Hui Jiang, Jinchen Guo, Xu Li, Fanfan Wang, Mingyu He, Qi Han, and Dan Huang. "Radix Salvia miltiorrhiza for Ankylosing Spondylitis: Determining Potential Inflammatory Molecular Targets and Mechanism Using Network Pharmacology." BioMed Research International 2022 (September 13, 2022): 1–13. http://dx.doi.org/10.1155/2022/3816258.

Full text

Abstract:

Radix Salvia miltiorrhiza (RSM) is widely used for the clinical improvement of inflammatory diseases. However, the actions of RSM in the treatment of ankylosing spondylitis (AS) have not been fully explored. Therefore, this study was designed to use retrospective clinical data mining approach to understand the effects of RSM on AS-related immuno-inflammatory processes, use network pharmacology to predict therapeutic targets of RSM, and to further investigate the pharmacological molecular mechanism in vitro. RSM treatment has a long-term correlation with the improvement of AS-related immuno-inflammatory indicators through computational models. We established protein-protein interaction networks, conducted KEGG analysis to enrich significant TNF pathways, and finally obtained three core targets of RSM in the treatment of AS, namely, prostaglandin endoperoxide synthase 2 (PTGS2), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). Screening of RSM active ingredients with node degree greater than 20 yielded cryptotanshinone and tanshinone IIA, and previous studies have reported their anti-inflammatory effects. In vitro, both cryptotanshinone and tanshinone IIA significantly inhibited the expressions of PTGS2, IL-6, and TNF-α in peripheral blood mononuclear cells in AS patients. In conclusion, cryptotanshinone and tanshinone IIA, which are the active components of RSM, may inhibit the activation of TNF signaling pathway in AS patients by downregulating the expression of PTGS2, IL-6, and TNF-α. These findings illustrate that RSM may be a promising therapeutic candidate for AS, but further validation is required.

APA, Harvard, Vancouver, ISO, and other styles

3

de Godoy, Márcio A. F., Neeru Rattan, and Satish Rattan. "Arachidonic acid metabolites follow the preferential course of cyclooxygenase pathway for the basal tone in the internal anal sphincter." American Journal of Physiology-Gastrointestinal and Liver Physiology 296, no. 4 (April 2009): G727—G734. http://dx.doi.org/10.1152/ajpgi.90707.2008.

Full text

Abstract:

Present studies determined the roles of the cyclooxygenase (COX) versus the lipoxygenase (LO) pathways in the metabolic pathway of arachidonic acid (AA) in the internal anal sphincter (IAS) tone. Studies were performed in the rat IAS versus the nontonic rectal smooth muscle (RSM). Indomethacin, the dual COX inhibitor, but not nordihydroguaiaretic acid (NDGA), the LO inhibitor, produced a precipitous decrease in the IAS tone. However, when added in the background of indomethacin, NDGA caused significant reversal of the IAS tone. These inhibitors had no significant effect on the RSM. To follow the significance of COX versus LO pathways, we examined the effects of AA and its metabolites. In the IAS, AA caused an increase in the IAS tone (Emax = 38.8 ± 3.0% and pEC50 = 3.4 ± 0.1). In the RSM, AA was significantly less efficacious and potent (Emax = 11.3 ± 3.5% and pEC50 = 2.2 ± 0.3). The AA metabolites (via COXs) PGF2α and U-46619 (a stable analog of thromboxane A2) produced increases in the IAS tone and force in the RSM. Conversely, AA metabolites (via 5-LO) lipoxin A4, 5-HETE, and leukotriene C4 decreased the IAS tone. Finally, the contractile effects of AA in the IAS were selectively attenuated by the COX-1 but not the COX-2 inhibitor. Collectively, the specific effects of AA and the COX inhibitor, the Western blot and RT-PCR analyses showing specifically higher levels of COX-1, suggest a preferential role of the COX (specifically COX-1) pathway versus the LO in the regulation of the IAS tone.

APA, Harvard, Vancouver, ISO, and other styles

4

Takeuchi, Kasumi, Kosumi Yamada, and Dieter Haas. "ppGpp Controlled by the Gac/Rsm Regulatory Pathway Sustains Biocontrol Activity in Pseudomonas fluorescens CHA0." Molecular Plant-Microbe Interactions® 25, no. 11 (November 2012): 1440–49. http://dx.doi.org/10.1094/mpmi-02-12-0034-r.

Full text

Abstract:

In Pseudomonas fluorescens CHA0 and other fluorescent pseudomonads, the Gac/Rsm signal transduction pathway is instrumental for secondary metabolism and biocontrol of root pathogens via the expression of regulatory small RNAs (sRNAs). Furthermore, in strain CHA0, an imbalance in the Krebs cycle can affect the strain's ability to produce extracellular secondary metabolites, including biocontrol factors. Here, we report the metabolome of wild-type CHA0, a gacA-negative mutant, which has lost Gac/Rsm activities, and a retS-negative mutant, which shows strongly enhanced Gac/Rsm-dependent activities. Capillary electrophoresis-based metabolomic profiling revealed that the gacA and retS mutations had opposite effects on the intracellular levels of a number of central metabolites, suggesting that the Gac/Rsm pathway regulates not only secondary metabolism but also primary metabolism in strain CHA0. Among the regulated metabolites identified, the alarmone guanosine tetraphosphate (ppGpp) was characterized in detail by the construction of relA (for ppGpp synthase) and spoT (for ppGpp synthase/hydrolase) deletion mutants. In a relA spoT double mutant, ppGpp synthesis was completely abolished, the expression of Rsm sRNAs was attenuated, and physiological functions such as antibiotic production, root colonization, and plant protection were markedly diminished. Thus, ppGpp appears to be essential for sustaining epiphytic fitness and biocontrol activity of strain CHA0.

APA, Harvard, Vancouver, ISO, and other styles

5

Yao, Yongli, Fan Hao, Lin-Chen Tang, Xiang-Hong Xu, and Liping Jin. "Downregulation of HDAC8 expression decreases CD163 levels and promotes the apoptosis of macrophages by activating the ERK signaling pathway in recurrent spontaneous miscarriage." Molecular Human Reproduction 26, no. 7 (May 20, 2020): 521–31. http://dx.doi.org/10.1093/molehr/gaaa035.

Full text

Abstract:

Abstract Recurrent spontaneous miscarriage (RSM) is a systemic disorder that has been defined as two or more pregnancies lost before the 20th week of gestation. Although the impaired function of macrophages at the maternal–fetal interface has been reported to be associated with RSM, the underlying mechanisms have not been fully elucidated. Here, we revealed that HDAC8 plays a critical role in RSM. Our results show that the mRNA and protein expression of HDAC8 was decreased in decidual macrophages from RSM patients. Moreover, the knockdown of HDAC8 resulted in a significant decrease in CD163 expression and an increase in apoptosis in dTHP-1 macrophages. Mechanistically, the ERK signaling pathway was activated in HDAC8-knockdown macrophages. When HDAC8-knockdown cells were pretreated with the ERK inhibitor U0126, expression levels of CD163, activated caspases 3, 7 and 9, and the apoptosis rate, were rescued. Taken together, our current results suggest that HDAC8 plays an important role in macrophage activation and apoptosis and may contribute to maintaining normal pregnancy by increasing the expression of M2 marker genes and inhibiting the apoptosis of macrophages at the maternal–fetal interface.

APA, Harvard, Vancouver, ISO, and other styles

6

Anderson, Anne J., Beom Ryong Kang, and Young Cheol Kim. "The Gac/Rsm Signaling Pathway of a Biocontrol Bacterium, Pseudomonas chlororaphis O6." Research in Plant Disease 23, no. 3 (September 30, 2017): 212–27. http://dx.doi.org/10.5423/rpd.2017.23.3.212.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Valverde, Claudio. "Artificial sRNAs activating the Gac/Rsm signal transduction pathway in Pseudomonas fluorescens." Archives of Microbiology 191, no. 4 (February 13, 2009): 349–59. http://dx.doi.org/10.1007/s00203-009-0459-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Rattan, Satish, and Jagmohan Singh. "RhoA/ROCK pathway is the major molecular determinant of basal tone in intact human internal anal sphincter." American Journal of Physiology-Gastrointestinal and Liver Physiology 302, no. 7 (April 1, 2012): G664—G675. http://dx.doi.org/10.1152/ajpgi.00430.2011.

Full text

Abstract:

The knowledge of molecular control mechanisms underlying the basal tone in the intact human internal anal sphincter (IAS) is critical for the pathophysiology and rational therapy for a number of debilitating rectoanal motility disorders. We determined the role of RhoA/ROCK and PKC pathways by comparing the effects of ROCK- and PKC-selective inhibitors Y 27632 and Gö 6850 (10−8to 10−4M), respectively, on the basal tone in the IAS vs. the rectal smooth muscle (RSM). Western blot studies were performed to determine the levels of RhoA/ROCK II, PKC-α, MYPT1, CPI-17, and MLC20in the unphosphorylated and phosphorylated forms, in the IAS vs. RSM. Confocal microscopic studies validated the membrane distribution of ROCK II. Finally, to confirm a direct relationship, we examined the enzymatic activities and changes in the basal IAS tone and p-MYPT1, p-CPI-17, and p-MLC20, before and after Y 27632 and Gö 6850. Data show higher levels of RhoA/ROCK II and related downstream signal transduction proteins in the IAS vs. RSM. In addition, data show a significant correlation between the active RhoA/ROCK levels, ROCK enzymatic activity, downstream proteins, and basal IAS tone, before and after ROCK inhibitor. From these data we conclude 1) RhoA/ROCK and downstream signaling are constitutively active in the IAS, and this pathway (in contrast with PKC) is the critical determinant of the basal tone in intact human IAS; and 2) RhoA and ROCK are potential therapeutic targets for a number of rectoanal motility disorders for which currently there is no satisfactory treatment.

APA, Harvard, Vancouver, ISO, and other styles

9

Yuan, Huayu, Qi Su, Yuehu Wang, Jiang Li, Baojun Liu, Yancheng Li, and Pan Wu. "Tetracycline catalytic photodegradation with mesoporous phosphated TiO2: characterization, process optimization and degradation pathway." RSC Advances 11, no. 18 (2021): 10975–85. http://dx.doi.org/10.1039/d1ra00516b.

Full text

Abstract:

The prepared P-TiO₂ has a perfect degradation effect on TC (99.16%) due to the loading of phosphate. The impact of multiple factors and the best degradation conditions were obtained by RSM. The possible degradation pathways of TC were proposed also.

APA, Harvard, Vancouver, ISO, and other styles

10

Takeuchi, Kasumi. "GABA, A Primary Metabolite Controlled by the Gac/Rsm Regulatory Pathway, Favors a Planktonic Over a Biofilm Lifestyle in Pseudomonas protegens CHA0." Molecular Plant-Microbe Interactions® 31, no. 2 (February 2018): 274–82. http://dx.doi.org/10.1094/mpmi-05-17-0120-r.

Full text

Abstract:

In Pseudomonas protegens CHA0 and other fluorescent pseudomonads, the Gac/Rsm signal transduction pathway is crucial for the expression of secondary metabolism and the biological control of fungi, nematodes, and insects. Based on the findings of a previous metabolomic study, the role of intracellular γ-aminobutyrate (GABA) as a potential signal in the Gac/Rsm pathway was investigated herein. The function and regulation of a gabDT (c01870-c01880) gene cluster in strain CHA0 were described. The gabT gene encoded GABA transaminase (GABAT) and enabled the growth of the bacterium on GABA, whereas the upstream gabD gene (annotated as a gene encoding succinic semialdehyde dehydrogenase) had an unknown function. A gacA mutant exhibited low GABAT activity, leading to the markedly greater intracellular accumulation of GABA than in the wild type. In the gacA mutant, the RsmA and RsmE proteins caused translational gabD repression, with concomitant gabT repression. Due to very low GABAT activity, the gabT mutant accumulated GABA to high levels. This trait promoted a planktonic lifestyle, reduced biofilm formation, and favored root colonization without exhibiting the highly pleiotropic gacA phenotypes. These results suggest an important role of GABA in the Gac/Rsm-regulated niche adaptation of strain CHA0 to plant roots.

APA, Harvard, Vancouver, ISO, and other styles

11

TAKEUCHI, K. "Turning the Gac/Rsm signal transduction pathway on and off in plant protecting bacteria." Japanese Journal of Phytopathology 81, no. 2 (2015): 105–10. http://dx.doi.org/10.3186/jjphytopath.81.105.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Lan, Zhou, Chen Zhao, Weiqun Guo, Xiong Guan, and Xiaolin Zhang. "Optimization of Culture Medium for Maximal Production of Spinosad Using an Artificial Neural Network - Genetic Algorithm Modeling." Journal of Molecular Microbiology and Biotechnology 25, no. 4 (2015): 253–61. http://dx.doi.org/10.1159/000381312.

Full text

Abstract:

Background: Spinosyns, products of secondary metabolic pathway of Saccharopolyspora spinosa, show high insecticidal activity, but difficulty in enhancing the spinosad yield affects wide application. The fermentation process is a key factor in this case. Methods: The response surface methodology (RMS) and artificial neural network (ANN) modeling were applied to optimize medium components for spinosad production using S. spinosa strain CGMCC4.1365. Experiments were performed using a rotatable central composite design, and the data obtained were used to construct an ANN model and an RSM model. Using a genetic algorithm (GA), the input space of the ANN model was optimized to obtain optimal values of medium component concentrations. Results: The regression coefficients (R2) for the ANN and RSM models were 0.9866 and 0.9458, respectively, indicating that the fitness of the ANN model was higher. The maximal spinosad yield (401.26 mg/l) was obtained using ANN/GA-optimized concentrations. Conclusion: The hybrid ANN/GA approach provides a viable alternative to the conventional RSM approach for the modeling and optimization of fermentation processes.

APA, Harvard, Vancouver, ISO, and other styles

13

Panijel, Mary, Laura Chalupowicz, Guido Sessa, Shulamit Manulis-Sasson, and Isaac Barash. "Global Regulatory Networks Control the Hrp Regulon of the Gall-Forming Bacterium Pantoea agglomerans pv. gypsophilae." Molecular Plant-Microbe Interactions® 26, no. 9 (September 2013): 1031–43. http://dx.doi.org/10.1094/mpmi-04-13-0097-r.

Full text

Abstract:

Gall formation by Pantoea agglomerans pv. gypsophilae is dependent on the hypersensitive response and pathogenicity (hrp) system. Previous studies demonstrated that PagR and PagI, regulators of the quorum-sensing system, induce expression of the hrp regulatory cascade (i.e., hrpXY, hrpS, and hrpL) that activates the HrpL regulon. Here, we isolated the genes of the Gac/Rsm global regulatory pathway (i.e., gacS, gacA, rsmB, and csrD) and of the post-transcriptional regulator rsmA. Our results demonstrate that PagR and PagI also upregulate expression of the Gac/Rsm pathway. PagR acts as a transcriptional activator of each of the hrp regulatory genes and gacA in a N-butanoyl-L-homoserine lactone-dependent manner as shown by gel shift experiments. Mutants of the Gac/Rsm genes or overexpression of rsmA significantly reduced Pantoea agglomerans virulence and colonization of gypsophila. Overexpression of rsmB sRNA abolished gall formation, colonization, and hypersensitive reaction on nonhost plants and prevented transcription of the hrp regulatory cascade, indicating a lack of functional type III secretion system. Expression of rsmB sRNA in the background of the csrD null mutant suggests that CsrD may act as a safeguard for preventing excessive production of rsmB sRNA. Results presented indicate that the hrp regulatory cascade is controlled directly by PagR and indirectly by RsmA, whereas deficiency in RsmA activity is epistatic to PagR induction.

APA, Harvard, Vancouver, ISO, and other styles

14

Latour, Xavier. "The Evanescent GacS Signal." Microorganisms 8, no. 11 (November 6, 2020): 1746. http://dx.doi.org/10.3390/microorganisms8111746.

Full text

Abstract:

The GacS histidine kinase is the membrane sensor of the major upstream two-component system of the regulatory Gac/Rsm signal transduction pathway. This pathway governs the expression of a wide range of genes in pseudomonads and controls bacterial fitness and motility, tolerance to stress, biofilm formation, and virulence or plant protection. Despite the importance of these roles, the ligands binding to the sensor domain of GacS remain unknown, and their identification is an exciting challenge in this domain. At high population densities, the GacS signal triggers a switch from primary to secondary metabolism and a change in bacterial lifestyle. It has been suggested, based on these observations, that the GacS signal is a marker of the emergence of nutritional stress and competition. Biochemical investigations have yet to characterize the GacS signal fully. However, they portray this cue as a low-molecular weight, relatively simple and moderately apolar metabolite possibly resembling, but nevertheless different, from the aliphatic organic acids acting as quorum-sensing signaling molecules in other Proteobacteria. Significant progress in the development of metabolomic tools and new databases dedicated to Pseudomonas metabolism should help to unlock some of the last remaining secrets of GacS induction, making it possible to control the Gac/Rsm pathway.

APA, Harvard, Vancouver, ISO, and other styles

15

Naz, Tahira, Yusuf Nazir, Shaista Nosheen, Samee Ullah, Hafiy Halim, Abu Bakr Ahmad Fazili, Shaoqi Li, et al. "Redirecting Metabolic Flux towards the Mevalonate Pathway for Enhanced β-Carotene Production in M. circinelloides CBS 277.49." BioMed Research International 2020 (December 29, 2020): 1–12. http://dx.doi.org/10.1155/2020/8890269.

Full text

Abstract:

Carotenoids produced by microbial sources are of industrial and medicinal importance due to their antioxidant and anticancer properties. In the current study, optimization of β-carotene production in M. circinelloides strain 277.49 was achieved using response surface methodology (RSM). Cerulenin and ketoconazole were used to inhibit fatty acids and the sterol biosynthesis pathway, respectively, in order to enhance β-carotene production by diverting metabolic pool towards the mevalonate pathway. All three variables used in screening experiments were found to be significant for the production of β-carotene. The synergistic effect of the C/N ratio, cerulenin, and ketoconazole was further evaluated and optimized for superior β-carotene production using central composite design of RSM. Our results found that the synergistic combination of C/N ratios, cerulenin, and ketoconazole at different concentrations affected the β-carotene productions significantly. The optimal production medium (std. order 11) composed of C/N 25, 10 μg/mL cerulenin, and 150 mg/L ketoconazole, producing maximum β-carotene of 4.26 mg/L (0.43 mg/g) which was 157% greater in comparison to unoptimized medium (1.68 mg/L, 0.17 mg/g). So, it was concluded that metabolic flux had been successfully redirected towards the mevalonate pathway for enhanced β-carotene production in CBS 277.49.

APA, Harvard, Vancouver, ISO, and other styles

16

Zhang, Wei, Zhao Zhao, Bo Zhang, Xiao-Gang Wu, Zheng-Guang Ren, and Li-Qun Zhang. "Posttranscriptional Regulation of 2,4-Diacetylphloroglucinol Production by GidA and TrmE in Pseudomonas fluorescens 2P24." Applied and Environmental Microbiology 80, no. 13 (April 18, 2014): 3972–81. http://dx.doi.org/10.1128/aem.00455-14.

Full text

Abstract:

ABSTRACTPseudomonas fluorescens2P24 is a soilborne bacterium that synthesizes and excretes multiple antimicrobial metabolites. The polyketide compound 2,4-diacetylphloroglucinol (2,4-DAPG), synthesized by thephlACBDlocus, is its major biocontrol determinant. This study investigated two mutants defective in antagonistic activity againstRhizoctonia solani. Deletion of thegidA(PM701) ortrmE(PM702) gene from strain 2P24 completely inhibited the production of 2,4-DAPG and its precursors, monoacetylphloroglucinol (MAPG) and phloroglucinol (PG). The transcription of thephlAgene was not affected, but the translation of thephlAandphlDgenes was reduced significantly. Two components of the Gac/Rsm pathway, RsmA and RsmE, were found to be regulated bygidAandtrmE, whereas the other components, RsmX, RsmY, and RsmZ, were not. The regulation of 2,4-DAPG production bygidAandtrmE, however, was independent of the Gac/Rsm pathway. Both thegidAandtrmEmutants were unable to produce PG but could convert PG to MAPG and MAPG to 2,4-DAPG. Overexpression of PhlD in thegidAandtrmEmutants could restore the production of PG and 2,4-DAPG. Taken together, these findings suggest that GidA and TrmE are positive regulatory elements that influence the biosynthesis of 2,4-DAPG posttranscriptionally.

APA, Harvard, Vancouver, ISO, and other styles

17

Rattan, Satish, Jagmohan Singh, Sumit Kumar, and Benjamin Phillips. "Nature of extracellular signal that triggers RhoA/ROCK activation for the basal internal anal sphincter tone in humans." American Journal of Physiology-Gastrointestinal and Liver Physiology 308, no. 11 (June 1, 2015): G924—G933. http://dx.doi.org/10.1152/ajpgi.00017.2015.

Full text

Abstract:

The extracellular signal that triggers activation of rho-associated kinase (RhoA/ROCK), the major molecular determinant of basal internal anal sphincter (IAS) smooth muscle tone, is not known. Using human IAS tissues, we identified the presence of the biosynthetic machineries for angiotensin II (ANG II), thromboxane A2 (TXA2), and prostaglandin F2α (PGF2α). These end products of the renin-angiotensin system (RAS) (ANG II) and arachidonic acid (TXA2 and PGF2α) pathways and their effects in human IAS vs. rectal smooth muscle (RSM) were studied. A multipronged approach utilizing immunocytochemistry, Western blot analyses, and force measurements was implemented. Additionally, in a systematic analysis of the effects of respective inhibitors along different steps of biosynthesis and those of antagonists, their end products were evaluated either individually or in combination. To further describe the molecular mechanism for the IAS tone via these pathways, we monitored RhoA/ROCK activation and its signal transduction cascade. Data showed characteristically higher expression of biosynthetic machineries of RAS and AA pathways in the IAS compared with the RSM. Additionally, specific inhibition of the arachidonic acid (AA) pathway caused ∼80% decrease in the IAS tone, whereas that of RAS lead to ∼20% decrease. Signal transduction studies revealed that the end products of both AA and RAS pathways cause increase in the IAS tone via activation of RhoA/ROCK. Both AA and RAS (via the release of their end products TXA2, PGF2α, and ANG II, respectively), provide extracellular signals which activate RhoA/ROCK for the maintenance of the basal tone in human IAS.

APA, Harvard, Vancouver, ISO, and other styles

18

Patel, Chirag A., and Satish Rattan. "Spontaneously tonic smooth muscle has characteristically higher levels of RhoA/ROK compared with the phasic smooth muscle." American Journal of Physiology-Gastrointestinal and Liver Physiology 291, no. 5 (November 2006): G830—G837. http://dx.doi.org/10.1152/ajpgi.00130.2006.

Full text

Abstract:

The internal anal sphincter (IAS) tone is important for the rectoanal continence. The RhoA/Rho kinase (ROK) pathway has been associated with the agonist-induced sustained contraction of the smooth muscle, but its role in the spontaneously tonic smooth muscle is not known. Present studies compared expression of different components of the RhoA/ROK pathway between the IAS (a truly tonic SM), the rectal smooth muscle (RSM) (a mixture of phasic and tonic), and anococcygeus smooth muscle (ASM) (a purely phasic SM) of rat. RT-PCR and Western blot analyses were performed to determine RhoA, ROCK-II, CPI-17, MYPT1, and myosin light-chain 20 (MLC20). Phosphorylated CPI-17 at threonine-38 residue (pThr38-CPI-17), MYPT1 at threonine-696 residue (pThr696-MYPT1), and MLC20 at threonine-18/serine-19 residues (pThr18/Ser19-MLC20) were also determined in the basal state and after pretreatment with the ROK inhibitor Y 27632. In addition, we compared the effect of Y 27632 on the basal isometric tension and ROK activity in the IAS vs. the RSM. Our data show the highest levels of RhoA, ROCK-II, CPI-17, MLC20, and of phospho-MYPT1, -CPI-17, and -MLC20 in the IAS followed by in the RSM and ASM. Conversely, MYPT1 levels were lowest in the IAS and highest in the ASM. In the IAS, Y 27632 caused a concentration-dependent decrease in the basal tone, levels of phospho-MYPT1, -CPI-17, and -MLC20, and ROK activity. We conclude that RhoA/ROK plays a critical role in the basal tone in the IAS by the inhibition of MLC phosphatase via the phosphorylation of MYPT1 and CPI-17.

APA, Harvard, Vancouver, ISO, and other styles

19

Lin, Qiqi, Jiahui Huang, Zhiqing Liu, Qunyi Chen, Xinbo Wang, Guohui Yu, Ping Cheng, Lian-Hui Zhang, and Zeling Xu. "tRNA modification enzyme MiaB connects environmental cues to activation of Pseudomonas aeruginosa type III secretion system." PLOS Pathogens 18, no. 12 (December 5, 2022): e1011027. http://dx.doi.org/10.1371/journal.ppat.1011027.

Full text

Abstract:

Pseudomonas aeruginosa, a major inhabitant of numerous environmental reservoirs, is a momentous opportunistic human pathogen associated with severe infections even death in the patients suffering from immune deficiencies or metabolic diseases. Type III secretion system (T3SS) employed by P. aeruginosa to inject effector proteins into host cells is one of the pivotal virulence factors pertaining to acute infections caused by this pathogen. Previous studies showed that P. aeruginosa T3SS is activated by various environmental cues such as calcium concentration and the host signal spermidine. However, how T3SS is regulated and expressed particularly under the ever-changing environmental conditions remains largely elusive. In this study, we reported that a tRNA modification enzyme PA3980, designated as MiaB, positively regulated T3SS gene expression in P. aeruginosa and was essential for the induced cytotoxicity of human lung epithelial cells. Further genetic assays revealed that MiaB promoted T3SS gene expression by repressing the LadS-Gac/Rsm signaling pathway and through the T3SS master regulator ExsA. Interestingly, ladS, gacA, rsmY and rsmZ in the LadS-Gac/Rsm signaling pathway seemed potential targets under the independent regulation of MiaB. Moreover, expression of MiaB was found to be induced by the cAMP-dependent global regulator Vfr as well as the spermidine transporter-dependent signaling pathway and thereafter functioned to mediate their regulation on the T3SS gene expression. Together, these results revealed a novel regulatory mechanism for MiaB, with which it integrates different environmental cues to modulate T3SS gene expression in this important bacterial pathogen.

APA, Harvard, Vancouver, ISO, and other styles

20

Zha, Daiming, Li Xu, Houjin Zhang, and Yunjun Yan. "The Two-Component GacS-GacA System ActivateslipATranslation by RsmE but Not RsmA in Pseudomonas protegens Pf-5." Applied and Environmental Microbiology 80, no. 21 (August 15, 2014): 6627–37. http://dx.doi.org/10.1128/aem.02184-14.

Full text

Abstract:

ABSTRACTInPseudomonasspp., the Gac-Rsm signal transduction system is required for the production of lipases. The current model assumes that the system induces lipase gene transcription mediated through the quorum-sensing (QS) system. However, there are no reports of a QS system based uponN-acyl homoserine lactones or the regulation of lipase gene expression inPseudomonas protegens. In this study, we investigated the regulatory mechanism acting onlipAexpression activated by the Gac-Rsm system inP. protegensPf-5 through deletion and overexpression ofgacA, overexpression ofrsmAorrsmE, expression of variouslacZfusions, reverse transcription-PCR analysis, and determination of whole-cell lipase activity. The results demonstrated that the GacS-GacA (GacS/A) system activateslipAexpression at both the transcriptional and the translational levels but that the translational level is the key regulatory pathway. Further results showed that the activation oflipAtranslation by the GacS/A system is mediated through RsmE, which inhibitslipAtranslation by binding to the ACAAGGAUGU sequence overlapping the Shine-Dalgarno (SD) sequence oflipAmRNA to hinder the access of the 30S ribosomal subunit to the SD sequence. Moreover, the GacS/A system promoteslipAtranscription through the mediation of RsmA inhibitinglipAtranscription via an unknown pathway. Besides the transcriptional repression, RsmA mainly activateslipAtranslation by negatively regulatingrsmEtranslation. In summary, inP. protegensPf-5, the Gac-RsmE system mainly and directly activateslipAtranslation and the Gac-RsmA system indirectly enhanceslipAtranscription.

APA, Harvard, Vancouver, ISO, and other styles

21

Lapouge, Karine, Elena Sineva, Magnus Lindell, Katja Starke, Carol S. Baker, Paul Babitzke, and Dieter Haas. "Mechanism of hcnA mRNA recognition in the Gac/Rsm signal transduction pathway of Pseudomonas fluorescens." Molecular Microbiology 66, no. 2 (September 14, 2007): 341–56. http://dx.doi.org/10.1111/j.1365-2958.2007.05909.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Tourang, Masoud, Xiaochao Xiong, Sara Sarkhosh, and Shulin Chen. "Polyhydroxybutyrate (PHB) Biosynthesis by an Engineered Yarrowia lipolytica Strain Using Co-Substrate Strategy." Fermentation 9, no. 12 (November 29, 2023): 1003. http://dx.doi.org/10.3390/fermentation9121003.

Full text

Abstract:

High production cost is one of the major factors that limit the market growth of polyhydroxyalkanoates (PHAs) as a biopolymer. Improving PHA synthesis performance and utilizing low-grade feedstocks are two logical strategies for reducing costs. As an oleaginous yeast, Y. lipolytica has a high carbon flux through acetyl-CoA (the main PHB precursor), which makes it a desired cell factory for PHB biosynthesis. In the current study, two different metabolic pathways (NBC and ABC) were introduced into Y. lipolytica PO1f for synthesizing PHB. Compared to the ABC pathway, the NBC pathway, which includes NphT7 to redirect the lipogenesis pathway and catalyze acetoacetyl-CoA synthesis in a more energy-favored reaction, led to PHB accumulation of up to 11% of cell dry weight (CDW), whereas the ABC pathway resulted in non-detectable accumulations of PHB. Further modifications of the strain with the NBC pathway through peroxisomal compartmentalization and gene dose overexpression reached 41% PHB of CDW and a growth rate of 0.227 h−1. A low growth rate was observed with acetate as the sole source of carbon and energy or glucose as the sole substrate at high concentrations. Using a co-substrate strategy helped overcoming the inhibitory and toxic effects of both substrates. Cultivating the engineered strain in the optimal co-substrate condition predicted by response surface methodology (RSM) led to 83.4 g/L of biomass concentration and 31.7 g/L of PHB. These results offer insight into a more cost-effective production of PHB with engineered Y. lipolytica.

APA, Harvard, Vancouver, ISO, and other styles

23

Ferreiro, María-Dolores, Joaquina Nogales, Gabriela A. Farias, Adela Olmedilla, Juan Sanjuán, and María Trinidad Gallegos. "Multiple CsrA Proteins Control Key Virulence Traits in Pseudomonas syringae pv. tomato DC3000." Molecular Plant-Microbe Interactions® 31, no. 5 (May 2018): 525–36. http://dx.doi.org/10.1094/mpmi-09-17-0232-r.

Full text

Abstract:

The phytopathogenic bacterium Pseudomonas syringae pv. tomato DC3000 has a complex Gac-rsm global regulatory pathway that controls virulence, motility, production of secondary metabolites, carbon metabolism, and quorum sensing. However, despite the fact that components of this pathway are known, their physiological roles have not yet been established. Regarding the CsrA/RsmA type proteins, five paralogs, three of which are well conserved within the Pseudomonas genus (csrA1, csrA2, and csrA3), have been found in the DC3000 genome. To decipher their function, mutants lacking the three most conserved CsrA proteins have been constructed and their physiological outcomes examined. We show that they exert nonredundant functions and demonstrate that CsrA3 and, to a lesser extent, CsrA2 but not CsrA1 alter the expression of genes involved in a variety of pathways and systems important for motility, exopolysaccharide synthesis, growth, and virulence. Particularly, alginate synthesis, syringafactin production, and virulence are considerably de-repressed in a csrA3 mutant, whereas growth in planta is impaired. We propose that the linkage of growth and symptom development is under the control of CsrA3, which functions as a pivotal regulator of the DC3000 life cycle, repressing virulence traits and promoting cell division in response to environmental cues.

APA, Harvard, Vancouver, ISO, and other styles

24

Lapouge, Karine, Mario Schubert, Frédéric H. T. Allain, and Dieter Haas. "Gac/Rsm signal transduction pathway of γ-proteobacteria: from RNA recognition to regulation of social behaviour." Molecular Microbiology 67, no. 2 (November 30, 2007): 241–53. http://dx.doi.org/10.1111/j.1365-2958.2007.06042.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Cao, Xianzhong, Huiqing Lou, Wei Wei, and Lijuan Zhu. "Treatment of tetrahydrofuran wastewater by the Fenton process: response surface methodology as an optimization tool." Water Science and Technology 69, no. 5 (January 21, 2014): 1080–87. http://dx.doi.org/10.2166/wst.2014.017.

Full text

Abstract:

In this study, the Box-Benkhen design and response surface method (RSM) were applied to evaluate and optimize the operating variables during the treatment of tetrahydrofuran (THF) wastewater by Fenton process. The four factors investigated were initial pH, Fe2+ dosage, H2O2 dosage and reaction time. Statistical analysis showed the linear coefficients of the four factors and the interactive coefficients such as initial pH/Fe2+ dosage, initial pH/H2O2 dosage and Fe2+ dosage/H2O2 dosage all significantly affected the removal efficiency. The RSM optimization results demonstrated that the chemical oxygen demand (COD) removal efficiency could reach up to 47.8% when initial pH was 4.49, Fe2+ dosage was 2.52 mM, H2O2 dosage was 20 mM and reaction time was 110.3 min. Simultaneously, the biodegradability increased obviously after the treatment. The main intermediates of 2-hydroxytetrahydrofuran, γ-butyrolactone and 4-hydroxybutanoate were separated and identified and then a simple degradation pathway of THF was proposed. This work indicated that the Fenton process was an efficient and feasible pre-treatment method for THF wastewater.

APA, Harvard, Vancouver, ISO, and other styles

26

Lee, Kian Mun, Sharifah Bee Abd Hamid, and Chin Wei Lai. "Mechanism and Kinetics Study for Photocatalytic Oxidation Degradation: A Case Study for Phenoxyacetic Acid Organic Pollutant." Journal of Nanomaterials 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/940857.

Full text

Abstract:

Photocatalysis is a rapidly expanding technology for wastewater treatment, including a wide range of organic pollutants. Thus, understanding the kinetics and mechanism of the photocatalytic oxidation (PCO) for degradation of phenoxyacetic acid (PAA) is an indispensable component of risk assessment. In this study, we demonstrated that the central composite design (CCD) coupled with response surface methodology (RSM) was successfully employed to probe the kinetics and mechanism of PCO degradation for PAA using an efficient zinc oxide (ZnO) photocatalyst. In our current case study, four independent factors such as ZnO dosage, initial concentration of PAA, solution pH, and reaction time on the PCO degradation for PAA were examined in detail. Based on our results obtained from RSM analyses, an efficient pathway leading to the high degradation rate (>90%) was applying 0.4 g/L of ZnO dosage with 16 mg/L of concentration of PAA at pH 6.73 for 40 minutes. The experimental results were fitted well with the derived response model withR2= 0.9922. This study offers a cost-effective way for probing our global environmental water pollution issue.

APA, Harvard, Vancouver, ISO, and other styles

27

Park, Jumin, Ji Eun Kim, You Jeong Jin, Yu Jeong Roh, Hee Jin Song, Ayun Seol, So Hae Park, Sungbaek Seo, Heeseob Lee, and Dae Youn Hwang. "Anti-Atopic Dermatitis Effects of Abietic Acid Isolated from Rosin under Condition Optimized by Response Surface Methodology in DNCB-Spread BALB/c Mice." Pharmaceuticals 16, no. 3 (March 7, 2023): 407. http://dx.doi.org/10.3390/ph16030407.

Full text

Abstract:

Abietic acid (AA) is known to have beneficial effects on inflammation, photoaging, osteoporosis, cancer, and obesity; however, its efficacy on atopic dermatitis (AD) has not been reported. We investigated the anti-AD effects of AA, which was newly isolated from rosin, in an AD model. To achieve this, AA was isolated from rosin under conditions optimized by response surface methodology (RSM), and its effects on cell death, iNOS-induced COX-2 mediated pathway, inflammatory cytokine transcription, and the histopathological skin structure were analyzed in 2,4-dinitrochlorobenzene (DNCB)-treated BALB/c mice after treatment with AA for 4 weeks. AA was isolated and purified through isomerization and reaction-crystallization under the condition (HCl, 2.49 mL; reflux extraction time, 61.7 min; ethanolamine, 7.35 mL) established by RSM, resulting in AA with a purity and extraction yield of 99.33% and 58.61%, respectively. AA exhibited high scavenging activity against DPPH, ABTS, and NO radicals as well as hyaluronidase activity in a dose-dependent manner. The anti-inflammatory effects of AA were verified in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages through amelioration of the inflammatory response, including NO production, iNOS-induced COX-2 mediated pathway activation, and cytokine transcription. In the DNCB-treated AD model, the skin phenotypes, dermatitis score, immune organ weight, and IgE concentration were significantly ameliorated in the AA cream (AAC)-spread groups compared to the vehicle-spread group. In addition, AAC spread ameliorated DNCB-induced deterioration of skin histopathological structure through the recovery of the thickness of the dermis and epidermis and the number of mast cells. Furthermore, activation of the iNOS-induced COX-2 mediated pathway and increased inflammatory cytokine transcription were ameliorated in the skin of the DNCB+AAC-treated group. Taken together, these results indicate that AA, newly isolated from rosin, exhibits anti-AD effects in DNCB-treated AD models, and has the potential to be developed as a treatment option for AD-related diseases.

APA, Harvard, Vancouver, ISO, and other styles

28

Gothwal, P., A. Kumar, D. Rathore, R. Mukherji, T. Vetriselvi, and S. Anandan. "Response Surface Methodology Analysis of Energy Harvesting System over Pathway Tiles." Materials 16, no. 3 (January 29, 2023): 1146. http://dx.doi.org/10.3390/ma16031146.

Full text

Abstract:

This paper presents an experimental analysis of the optimization of PZT-based tiles for energy harvesting. The hardware (actual experiment), PZT-based tiles, were developed using 6 × 6 piezoelectric (PZT—lead zirconate titanate) sensors of 40 mm in diameter on a hard cardboard sheet (300 × 300 mm2). Our experimental analysis of the designed tiles obtained an optimized power of 3.626 mW (85 kg or 0.83 kN using 36 sensors) for one footstep and 0.9 mW for 30 footsteps at high tapping frequency. Theoretical analysis was conducted with software (Design-Expert) using the response surface methodology (RSM) for optimized PZT tiles, obtaining a power of 6784.155 mW at 150 kg or 1.47 kN weight using 34 sensors. This software helped to formulate the mathematical equation for the most suitable PZT tile model for power optimization. It used the quadratic model to provide adjusted and predicted R2 values of 0.9916 and 0.9650, respectively. The values were less than 0.2 apart, which indicates a high correlation between the actual and predicted values. The outcome of the various experiments can help with the selection of input factors for optimized power during pavement design.

APA, Harvard, Vancouver, ISO, and other styles

29

Takeuchi, Kasumi, Wataru Tsuchiya, Naomi Noda, Rintaro Suzuki, Toshimasa Yamazaki, and Dieter Haas. "Lon protease negatively affects GacA protein stability and expression of the Gac/Rsm signal transduction pathway inPseudomonas protegens." Environmental Microbiology 16, no. 8 (February 18, 2014): 2538–49. http://dx.doi.org/10.1111/1462-2920.12394.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Wang, Dongping, Sung‐Hee Lee, Candace Seeve, Jun Myoung Yu, Leland S. Pierson, and Elizabeth A. Pierson. "Roles of the Gac‐Rsm pathway in the regulation of phenazine biosynthesis in P seudomonas chlororaphis 30‐84." MicrobiologyOpen 2, no. 3 (April 21, 2013): 505–24. http://dx.doi.org/10.1002/mbo3.90.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Hong, Zhong-Yun, Lung-Chuan Chen, Yu-Chu M. Li, Hao-Lin Hsu, and Chao-Ming Huang. "Response Surface Methodology Optimization in High-Performance Solid-State Supercapattery Cells Using NiCo2S4–Graphene Hybrids." Molecules 27, no. 20 (October 13, 2022): 6867. http://dx.doi.org/10.3390/molecules27206867.

Full text

Abstract:

In this work, NiCo2S4–graphene hybrids (NCS@G) with high electrochemical performance were prepared using a hydrothermal method. The response surface methodology (RSM), along with a central composite design (CCD), was used to investigate the effect of independent variables (G/NCS, hydrothermal time, and S/Ni) on the specific capacitances of the NCS@G/Ni composite electrodes. RSM analysis revealed that the developed quadratic model with regression coefficient values of more than 0.95 could be well adapted to represent experimental results. Optimized preparation conditions for NCS@G were G/NCS = 6.0%, hydrothermal time = 10.0, and S/Ni = 6.0 of NCS@G (111) sample. The maximum specific capacitance of NCS@G (111)/Ni fabricated at the optimal condition is about 216% higher than the best result obtained using the conventional experimental method. The enhanced capacitive performance of the NCS@G (111) sample can be attributed to the synergistic effect between NCS nanoparticles and graphene, which has the meso/macropores conductive network and low diffusion resistance. Notably, the NCS@G (111) could not only provide numerous reaction sites but also prevent the restacking of graphene layers. Furthermore, a supercapattery cell was fabricated with an (G + AC)/Ni anode, a NCS@G (111)/Ni cathode, and a carboxymethyl cellulose–potassium hydroxide (CMC-KOH) gel electrolyte. The NCS@G (111)//(G + AC) demonstrates an outstanding energy density of 80 Wh kg−1 at a power density of 4 kW kg−1, and a good cycling performance of 75% after 5000 cycles at 2 A g−1. Applying the synthesis strategy of RSM endows remarkable capacitive performance of the hybrid materials, providing an economical pathway to design promising composite electrode material and fabricate high-performance energy storage devices.

APA, Harvard, Vancouver, ISO, and other styles

32

Mirzaei, Amir, Laleh Yerushalmi, Zhi Chen, and Fariborz Haghighat. "Photocatalytic degradation of sulfamethoxazole by hierarchical magnetic ZnO@g-C3N4: RSM optimization, kinetic study, reaction pathway and toxicity evaluation." Journal of Hazardous Materials 359 (October 2018): 516–26. http://dx.doi.org/10.1016/j.jhazmat.2018.07.077.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Bhagirath, Anjali Y., Deepti Somayajula, Yanqi Li, and Kangmin Duan. "CmpX Affects Virulence in Pseudomonas aeruginosa Through the Gac/Rsm Signaling Pathway and by Modulating c-di-GMP Levels." Journal of Membrane Biology 251, no. 1 (October 23, 2017): 35–49. http://dx.doi.org/10.1007/s00232-017-9994-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Li, Xin, Hongyu Dong, Shaoqing Guo, and Liangfu Zhao. "Study on the Curing Process of Silver Paste of Heterojunction Solar Cells Using Response Surface Methodology." Applied Sciences 10, no. 14 (July 15, 2020): 4857. http://dx.doi.org/10.3390/app10144857.

Full text

Abstract:

Adhesion strength is of great importance for silver paste of heterojunction solar cells (HJT silver paste). It has a close relation with the curing system, as well as the curing process or curing conditions of the paste. The interactions among all the curing conditions such as curing time (t, min), treatment temperature (T, °C), and curing agent dosage (m, wt%) are obviously complex and hard to analyze. Response surface methodology (RSM) is used to research the interactions among t, T, and m and to optimize the curing process. The results of this study indicate that an increase of curing time and treatment temperature both had a positive effect on adhesion strength. The effect of curing time is more obvious under a lower treatment temperature. 41 wt%, 199 °C, and 44 min were determined as the optimum process conditions. The quadratic model predictions fitted well with the experimental data with a deviation less than 3%. The FTIR results indicated that there were both addition and esterification processes in the reaction of E51 and ring-open MeTHPA. Scanning electron microscopy (SEM) images showed that the silver paste formed a dense interconnected network and provided a continuous pathway for current carrier transmission. This research demonstrated the effectiveness of the E51-MeTHPA system for HJT silver paste and the superiority of RSM in studying the curing process of silver paste.

APA, Harvard, Vancouver, ISO, and other styles

35

Chakraborty, Debkumar, Gaganjot Gupta, and Baljinder Kaur. "Metabolic engineering of E. coli top 10 for production of vanillin through FA catabolic pathway and bioprocess optimization using RSM." Protein Expression and Purification 128 (December 2016): 123–33. http://dx.doi.org/10.1016/j.pep.2016.08.015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Youssef, Omar, Esraa Khaled, Omar Aboelazayem, and Nessren Farrag. "Glycerol-Free Biodiesel via Catalytic Interesterification: A Pathway to a NetZero Biodiesel Industry." Sustainability 16, no. 12 (June 12, 2024): 4994. http://dx.doi.org/10.3390/su16124994.

Full text

Abstract:

Conventional biodiesel manufacturing uses alcohol as an acyl acceptor, resulting in glycerol as a side product. The increased demand for biodiesel has led to the production of a substantial surplus of glycerol, exceeding the market need. Consequently, glycerol is now being regarded as a byproduct, and in some cases, even as waste. The present study aims to suggest an economically viable and ecologically friendly approach for maintaining the viability of the biodiesel sector. This involves generating an alternative byproduct of higher value, rather than glycerol. Triacetin is produced through the interesterification of triglycerides with methyl acetate, and is a beneficial ingredient to biodiesel, reducing the need for extensive product separation. The primary objective of this research is to improve the interesterification reaction by optimising process parameters to maximise biodiesel production while using sulphuric acid as an economically viable catalyst. The study utilised the Box–Behnken design (BBD) to investigate the influence of various process variables on biodiesel yield, such as reaction time, methyl acetate to oil molar ratio, and catalyst concentration. An optimisation study using Response Surface Methodology (RSM) focused on key process reaction parameters, including the methyl acetate to oil (MA:O) molar ratio, catalyst concentration, and residence time. The best conditions produced a biodiesel blend with a 142% yield at a 12:1 MA:O molar ratio, with 0.1 wt% of catalyst loading within 1.7 h. The established technique is deemed to be undeniably effective, resulting in an efficient biodiesel production process.

APA, Harvard, Vancouver, ISO, and other styles

37

Jiang, Nan, Yonghe Zhao, Kefeng Shang, Na Lu, Jie Li, and Yan Wu. "Degradation of toluene by pulse-modulated multistage DBD plasma: Key parameters optimization through response surface methodology (RSM) and degradation pathway analysis." Journal of Hazardous Materials 393 (July 2020): 122365. http://dx.doi.org/10.1016/j.jhazmat.2020.122365.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Mahanna, Hani, Asmaa Fawzy, and Mohamed Mossad. "Novel MIL-53(Fe)/ZnO nanocomposite mediated by persulfate in photocatalytic degradation of sulfamethazine under visible light." Environmental Engineering Research 29, no. 4 (November 18, 2023): 230458–0. http://dx.doi.org/10.4491/eer.2023.458.

Full text

Abstract:

This work aims to address some significant restrictions on the use of photocatalysis, including high e-/h+ recombination rate, and semiconductors with wide-band energy resulting in limited visible-light harvesting. Herein, we apply a novel hierarchical MIL-53(Fe)/ZnO nanocomposite for the degradation of sulfamethazine in the presence of persulfate under visible light irradiation. The ultrafine nanocomposite MIL-53(Fe)/ZnO was obtained by synthesizing Zn-free MIL-53Fe and employing it as a reactive template under a hydrothermal process. A set of experiments with a Box Behnken design was conducted to optimize the operating parameters by response surface method (RSM). Complete degradation of 10 mg/L of SMZ was attained after 30 min under the optimum operational conditions (catalyst dose = 0.2 g/L, pH = 3, and persulfate loading = 0.39 g/L). The SMZ degradation followed the Langmuir-Hinshelwood model. In addition, about 78% TOC removal was observed under the optimum conditions. Also, it was proven that MIL-53(Fe)/ZnO had high photostability after being reused for five successive cycles. A possible degradation pathway of SMZ was proposed based on the detection results of intermediates by LC-MS/MS, suggesting that the cleavage of the S-N bond and subsequent removal of sulfone moiety was the primary degradation pathway.

APA, Harvard, Vancouver, ISO, and other styles

39

Hua, Wan, Sarantos Kostidis, Oleg Mayboroda, Martin Giera, Marten Hornsveld, and Peter ten Dijke. "Metabolic Reprogramming of Mammary Epithelial Cells during TGF-β-Induced Epithelial-to-Mesenchymal Transition." Metabolites 11, no. 9 (September 15, 2021): 626. http://dx.doi.org/10.3390/metabo11090626.

Full text

Abstract:

The cytokine transforming growth factor-β (TGF-β) can induce normal breast epithelial cells to take on a mesenchymal phenotype, termed epithelial-to-mesenchymal transition (EMT). While the transcriptional and proteomic changes during TGF-β-induced EMT have been described, the metabolic rewiring that occurs in epithelial cells undergoing EMT is not well understood. Here, we quantitively analyzed the TGF-β-induced metabolic reprogramming during EMT of non-transformed NMuMG mouse mammary gland epithelial cells using nuclear magnetic resonance (NMR) spectroscopy. We found that TGF-β elevates glycolytic and tricarboxylic acid (TCA)-cycle activity and increases glutaminolysis. Additionally, TGF-β affects the hexosamine pathway, arginine-proline metabolism, the cellular redox state, and strongly affects choline metabolism during EMT. TGF-β was found to induce phosphocholine production. A kinase inhibitor RSM-93A that inhibits choline kinase α (CHKα) mitigated TGF-β-induced changes associated with EMT, i.e., increased filamentous (F)-actin stress fiber formation and N-Cadherin mesenchymal marker expression.

APA, Harvard, Vancouver, ISO, and other styles

40

Bian, Chun, Zhenyu Wang, and John Shi. "Extraction Optimization, Structural Characterization, and Anticoagulant Activity of Acidic Polysaccharides from Auricularia auricula-judae." Molecules 25, no. 3 (February 6, 2020): 710. http://dx.doi.org/10.3390/molecules25030710.

Full text

Abstract:

To explore Auricularia auricula-judae polysaccharides (AAP) as natural anticoagulants for application in the functional food industry, ultrasound assisted extraction (UAE) was optimized for the extraction of AAP by using a response surface methodology (RSM). The maximum extraction yield of crude AAP (14.74 mg/g) was obtained at the optimized extraction parameters as follows: Extraction temperature (74 °C), extraction time (27 min), the ratio of liquid to raw material (103 mL/g), and ultrasound power (198 W). Furthermore, the acidic AAP (aAAP) was precipitated with cetyltrimethylammonium bromide (CTAB) from crude AAP (cAAP). aAAP was further purified using ion exchange chromatography with a DEAE Purose 6 Fast Flow column to obtain aAAP-1. Additionally, according to the HPLC analysis, the aAAP-1 was mainly composed of mannose, glucuronic acid, glucose, galactose, and xylose, with a molar ratio of 80.63:9.88:2.25:1:31.13. Moreover, the results of the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) indicated aAAP-1 had anticoagulant activity, which was a synergic anticoagulant activity by the endogenous and exogenous pathway.

APA, Harvard, Vancouver, ISO, and other styles

41

Pérez-Martínez, Isabel, and Dieter Haas. "Azithromycin Inhibits Expression of the GacA-Dependent Small RNAs RsmY and RsmZ in Pseudomonas aeruginosa." Antimicrobial Agents and Chemotherapy 55, no. 7 (May 2, 2011): 3399–405. http://dx.doi.org/10.1128/aac.01801-10.

Full text

Abstract:

ABSTRACTAzithromycin at clinically relevant doses does not inhibit planktonic growth of the opportunistic pathogenPseudomonas aeruginosabut causes markedly reduced formation of biofilms and quorum-sensing-regulated extracellular virulence factors. In the Gac/Rsm signal transduction pathway, which acts upstream of the quorum-sensing machinery inP. aeruginosa, the GacA-dependent untranslated small RNAs RsmY and RsmZ are key regulatory elements. As azithromycin treatment and mutational inactivation ofgacAhave strikingly similar phenotypic consequences, the effect of azithromycin onrsmYandrsmZexpression was investigated. In planktonically growing cells, the antibiotic strongly inhibited the expression of both small RNA genes but did not affect the expression of the housekeeping geneproC. The azithromycin treatment resulted in reduced expression ofgacAandrsmA, which are known positive regulators ofrsmYandrsmZ, and of the PA0588-PA0584 gene cluster, which was discovered as a novel positive regulatory element involved inrsmYandrsmZexpression. Deletion of this cluster resulted in diminished ability ofP. aeruginosato produce pyocyanin and to swarm. The results of this study indicate that azithromycin inhibitsrsmYandrsmZtranscription indirectly by lowering the expression of positive regulators of these small RNA genes.

APA, Harvard, Vancouver, ISO, and other styles

42

Li, Yuanyuan, Lei Huang, Yongfang Xu, Biao Cheng, and Mingqin Zhao. "Optimization of Enzyme-Assisted Extraction of Rosemary Essential Oil Using Response Surface Methodology and Its Antioxidant Activity by Activating Nrf2 Signaling Pathway." Molecules 29, no. 14 (July 18, 2024): 3382. http://dx.doi.org/10.3390/molecules29143382.

Full text

Abstract:

Rosemary essential oil (REO) is widely recognized as a food flavoring and traditional herb and possesses potential antioxidant activity. However, its low yield rate and unclarified antioxidant mechanism warrant further investigation. In this study, an enzyme pretreatment-assisted extraction method with Box–Behnken design (BBD) and response surface methodology (RSM) models was employed to optimize the main factors of REO, and its antioxidant molecular mechanism under oxidative stress was elucidated in hydrogen peroxide-induced human lung carcinoma (A549) cells. The optimized yield (4.10%) of REO was recorded with the following optimum conditions: enzyme amount 1.60%, enzyme digestion pH 5.0, enzyme digestion temperature 46.50 °C, and enzyme digestion time 1.7 h. Meanwhile, 1.8-cineole (53.48%) and β-pinene (20.23%) exhibited radical scavenging activity higher than that of BHA and BHT. At the cellular level, REO (12.5–50 µg/mL) increased the levels of cell viability, CAT, SOD, and GSH significantly while reducing the contents of ROS, MDA, and GSSG, when compared to H2O2 exposure. Mechanically, REO relieved oxidative stress via activating the Nrf2 signaling pathway and enhancing the protein expression of Nrf2, NQO-1, and HO-1, which was further verified by molecular docking between the main component 1.8-cineole and the Kelch domain of KEAP1. Therefore, REO could be considered as a potent natural antioxidant with a potential strategy in the food and pharmaceutical industries.

APA, Harvard, Vancouver, ISO, and other styles

43

Minnalkodi Senguttuvan, Keerthana Rani, Kanmani Sellappa, and Saranya Kuppusamy. "Performance Evaluation of the Electro-Fenton Process for Distillery Wastewater Treatment." Sustainability 16, no. 15 (July 30, 2024): 6512. http://dx.doi.org/10.3390/su16156512.

Full text

Abstract:

A fair amount of India’s gross domestic product is contributed by distilleries, which are considered the backbone industries of India. Distilleries indeed play key roles in India’s exports. Distillery wastewater is recognized as one of the recalcitrant wastewaters, containing extremely high organic loading and having an adverse impact when released into the environment. The aim of the present study was to optimize the conditions required for attaining improved COD removal efficiency in distillery wastewater through an electro-Fenton (EF) process. The effect of various operating parameters, viz. H2O2 dosage (555–2220 mg L−1), spacing between the iron electrodes (2–6 cm), electrode dipping area (35–65 cm2), initial pH (2–9), and constant voltage supply (5–15 V), were investigated by carrying out the EF process in batch mode. As a result of the EF study, COD removal efficiency of 79.5% for an initial COD of 5500–6000 mg L−1 was achieved for the distillery wastewater under the condition of 1665 mg L−1 H2O2, 2.5 cm of spacing between the electrodes, 55 cm2 of electrode dipping area, pH 3, and constant voltage supply of 5 V. In the same study, the kinetics of the process was also investigated, and it obeyed the pseudo-first-order reaction. The EF process effectively degrades complex organic compounds in distillery wastewater into simpler, potentially less toxic substances, as demonstrated by gas chromatography–mass spectrometry (GC-MS) analysis and pathway elucidation. The central composite design (CCD) of the response surface methodology (RSM) model was used to optimize the COD removal in distillery wastewater through the EF process. In line with the batch experimental results, RSM projections also indicated that the optimum conditions required for attaining a maximum of 70.8% COD removal efficiency in distillery wastewater are found to be 1402 mg L−1 H2O2 dosage, 3 cm electrode spacing, 60 cm2 dipping area, 5 V voltage, and pH 2.18. The research data supported the conclusion that the EF process is feasible for distillery wastewater treatment, which preferably can be applied extensively.

APA, Harvard, Vancouver, ISO, and other styles

44

Dargahi, Abdollah, Mehdi Vosoughi, S. Ahmad Mokhtari, Yaser Vaziri, and Mortaza Alighadri. "Electrochemical degradation of 2,4-Dinitrotoluene (DNT) from aqueous solutions using three-dimensional electrocatalytic reactor (3DER): Degradation pathway, evaluation of toxicity and optimization using RSM-CCD." Arabian Journal of Chemistry 15, no. 3 (March 2022): 103648. http://dx.doi.org/10.1016/j.arabjc.2021.103648.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Lee, Gillian Li Yin, Nur Nadhirah Zakaria, Peter Convey, Hiroyuki Futamata, Azham Zulkharnain, Kenshi Suzuki, Khalilah Abdul Khalil, et al. "Statistical Optimisation of Phenol Degradation and Pathway Identification through Whole Genome Sequencing of the Cold-Adapted Antarctic Bacterium, Rhodococcus sp. Strain AQ5-07." International Journal of Molecular Sciences 21, no. 24 (December 9, 2020): 9363. http://dx.doi.org/10.3390/ijms21249363.

Full text

Abstract:

Study of the potential of Antarctic microorganisms for use in bioremediation is of increasing interest due to their adaptations to harsh environmental conditions and their metabolic potential in removing a wide variety of organic pollutants at low temperature. In this study, the psychrotolerant bacterium Rhodococcus sp. strain AQ5-07, originally isolated from soil from King George Island (South Shetland Islands, maritime Antarctic), was found to be capable of utilizing phenol as sole carbon and energy source. The bacterium achieved 92.91% degradation of 0.5 g/L phenol under conditions predicted by response surface methodology (RSM) within 84 h at 14.8 °C, pH 7.05, and 0.41 g/L ammonium sulphate. The assembled draft genome sequence (6.75 Mbp) of strain AQ5-07 was obtained through whole genome sequencing (WGS) using the Illumina Hiseq platform. The genome analysis identified a complete gene cluster containing catA, catB, catC, catR, pheR, pheA2, and pheA1. The genome harbours the complete enzyme systems required for phenol and catechol degradation while suggesting phenol degradation occurs via the β-ketoadipate pathway. Enzymatic assay using cell-free crude extract revealed catechol 1,2-dioxygenase activity while no catechol 2,3-dioxygenase activity was detected, supporting this suggestion. The genomic sequence data provide information on gene candidates responsible for phenol and catechol degradation by indigenous Antarctic bacteria and contribute to knowledge of microbial aromatic metabolism and genetic biodiversity in Antarctica.

APA, Harvard, Vancouver, ISO, and other styles

46

Lv, Hongxia, Peiwei Han, Xiaogang Li, Zhao Mu, Yuan Zuo, Xu Wang, Yannan Tan, et al. "Electrocatalytic Degradation of Levofloxacin, a Typical Antibiotic in Hospital Wastewater." Materials 14, no. 22 (November 11, 2021): 6814. http://dx.doi.org/10.3390/ma14226814.

Full text

Abstract:

Presently, in the context of the novel coronavirus pneumonia epidemic, several antibiotics are overused in hospitals, causing heavy pressure on the hospital’s wastewater treatment process. Therefore, developing stable, safe, and efficient hospital wastewater treatment equipment is crucial. Herein, a bench-scale electrooxidation equipment for hospital wastewater was used to evaluate the removal effect of the main antibiotic levofloxacin (LVX) in hospital wastewater using response surface methodology (RSM). During the degradation process, the influence of the following five factors on total organic carbon (TOC) removal was discussed and the best reaction condition was obtained: current density, initial pH, flow rate, chloride ion concentration, and reaction time of 39.6 A/m2, 6.5, 50 mL/min, 4‰, and 120 min, respectively. The TOC removal could reach 41% after a reaction time of 120 min, which was consistent with the result predicted by the response surface (40.48%). Moreover, the morphology and properties of the electrode were analyzed. The degradation pathway of LVX was analyzed using high-performance liquid chromatography–mass spectrometry (LC–MS). Subsequently, the bench-scale electrooxidation equipment was changed into onboard-scale electrooxidation equipment, and the onboard-scale equipment was promoted to several hospitals in Dalian.

APA, Harvard, Vancouver, ISO, and other styles

47

Dubuis, Christophe, Joëlle Rolli, Matthias Lutz, Geneviève Défago, and Dieter Haas. "Thiamine-Auxotrophic Mutants of Pseudomonas fluorescens CHA0 Are Defective in Cell-Cell Signaling and Biocontrol Factor Expression." Applied and Environmental Microbiology 72, no. 4 (April 2006): 2606–13. http://dx.doi.org/10.1128/aem.72.4.2606-2613.2006.

Full text

Abstract:

ABSTRACT In the biocontrol strain Pseudomonas fluorescens CHA0, the Gac/Rsm signal transduction pathway positively controls the synthesis of antifungal secondary metabolites and exoenzymes. In this way, the GacS/GacA two-component system determines the expression of three small regulatory RNAs (RsmX, RsmY, and RsmZ) in a process activated by the strain's own signal molecules, which are not related to N-acyl-homoserine lactones. Transposon Tn5 was used to isolate P. fluorescens CHA0 insertion mutants that expressed an rsmZ-gfp fusion at reduced levels. Five of these mutants were gacS negative, and in them the gacS mutation could be complemented for exoproduct and signal synthesis by the gacS wild-type allele. Furthermore, two thiamine-auxotrophic (thiC) mutants that exhibited decreased signal synthesis in the presence of 5 × 10−8 M thiamine were found. Under these conditions, a thiC mutant grew normally but showed reduced expression of the three small RNAs, the exoprotease AprA, and the antibiotic 2,4-diacetylphloroglucinol. In a gnotobiotic system, a thiC mutant was impaired for biological control of Pythium ultimum on cress. Addition of excess exogenous thiamine restored all deficiencies of the mutant. Thus, thiamine appears to be an important factor in the expression of biological control by P. fluorescens.

APA, Harvard, Vancouver, ISO, and other styles

48

Kong, Hye Suk, Daniel P. Roberts, Cheryl D. Patterson, Sarah A. Kuehne, Stephan Heeb, Dilip K. Lakshman, and John Lydon. "Effect of Overexpressing rsmA from Pseudomonas aeruginosa on Virulence of Select Phytotoxin-Producing Strains of P. syringae." Phytopathology® 102, no. 6 (June 2012): 575–87. http://dx.doi.org/10.1094/phyto-09-11-0267.

Full text

Abstract:

The GacS/GacA two-component system functions mechanistically in conjunction with global post-transcriptional regulators of the RsmA family to allow pseudomonads and other bacteria to adapt to changing environmental stimuli. Analysis of this Gac/Rsm signal transduction pathway in phytotoxin-producing pathovars of Pseudmonas syringae is incomplete, particularly with regard to rsmA. Our approach in studying it was to overexpress rsmA in P. syringae strains through introduction of pSK61, a plasmid constitutively expressing this gene. Disease and colonization of plant leaf tissue were consistently diminished in all P. syringae strains tested (pv. phaseolicola NPS3121, pv. syringae B728a, and BR2R) when harboring pSK61 relative to these isolates harboring the empty vector pME6031. Phaseolotoxin, syringomycin, and tabtoxin were not produced in any of these strains when transformed with pSK61. Production of protease and pyoverdin as well as swarming were also diminished in all of these strains when harboring pSK61. In contrast, alginate production, biofilm formation, and the hypersensitive response were diminished in some but not all of these isolates under the same growth conditions. These results indicate that rsmA is consistently important in the overarching phenotypes disease and endophtyic colonization but that its role varies with pathovar in certain underpinning phenotypes in the phytotoxin-producing strains of P. syringae.

APA, Harvard, Vancouver, ISO, and other styles

49

Yang, Shihui, Qiu Zhang, Jianhua Guo, Amy O. Charkowski, Bernard R. Glick, A. Mark Ibekwe, Donald A. Cooksey, and Ching-Hong Yang. "Global Effect of Indole-3-Acetic Acid Biosynthesis on Multiple Virulence Factors of Erwinia chrysanthemi 3937." Applied and Environmental Microbiology 73, no. 4 (December 22, 2006): 1079–88. http://dx.doi.org/10.1128/aem.01770-06.

Full text

Abstract:

ABSTRACT Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway.

APA, Harvard, Vancouver, ISO, and other styles

50

Bora, Popy, Sukanya Gogoi, Mukund Vinayak Deshpande, Pankaj Garg, Rana P. Bhuyan, Nilofar Altaf, Nikita Saha, et al. "Rhizospheric Bacillus spp. Exhibit Miticidal Efficacy against Oligonychus coffeae (Acari: Tetranychidae) of Tea." Microorganisms 11, no. 11 (November 2, 2023): 2691. http://dx.doi.org/10.3390/microorganisms11112691.

Full text

Abstract:

Oligonychus coffeae (Acari: Tetranychidae), popularly known as red spider mite (RSM) is one of the major pests of commercial tea (Camellia sinensis (L.) O. Kuntze) plantation world over. Many attempts have been made in the past to control this devastating pest using a variety of microbial bioagents, however, area-wise field success is very limited. We carried out an in vitro study to explore the potential of rhizospheric Bacillus spp. (B. amyloliquefaciens BAC1, B. subtilis LB22, and B. velezensis AB22) against O. coffeae through adulticidal and ovicidal activity. The 100% adult and egg mortality was observed with bacterial suspension (1 × 109 CFU/mL) by B. velezensis AB22, showing the lowest LC50 values for both adults and eggs of O. coffeae, i.e., 0.28 × 105 and 0.29 × 105, respectively. The study also throws some insights into the underlying mechanism through electron microscopy study and identification of some putative pesticidal metabolites from all the species. The three Bacillus species were observed to have four commonly secreted putative bioactive secondary metabolites, brevianamide A, heptadecanoic acid, thiolutin, and versimide responsible for their bio-efficacy against O. coffeae. The outcome of our study provides a strong possibility of introducing Bacillus spp. as a biological miticide and developing synthetic metabolites mimicking the mechanistic pathway involved in microbial bioefficacy.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Rsm pathway'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles