Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
1.
Nanomaterials (Basel) ; 14(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38535697

RESUMO

Formic acid has emerged as a highly promising hydrogen storage material, and the development of efficient catalysts to facilitate its dehydrogenation remains imperative. In this study, a novel catalyst consisting of palladium nanoparticles supported on boron-doped porous carbon (Pd/BPC) was successfully synthesized to enable efficient hydrogen production through the dehydrogenation of formic acid. The impacts of the boron doping ratio, doping temperature, and palladium reduction temperature on the catalyst's performance were systemically investigated. The results demonstrated the Pd/BPC catalyst synthesized with a carbon-to-boron ratio of 1:5 by calcination at 900 °C and subsequent reduction at 60 °C exhibited superior formic acid dehydrogenation performance, being 2.9 and 3.8 times greater than that of the Pd/PC catalysts without boron doping and commercial Pd/C, respectively. Additionally, the catalyst showed excellent cycle stability with no significant activity reduction after five consecutive cycles. Experimental and theoretical results reveal that boron doping not only facilitates the homogenous distribution of Pd nanoparticles but also induces a stronger support-metal interaction, thereby reinforcing the catalytic performance. This research is expected to provide valuable insights into the economically viable and efficient production of environmentally friendly hydrogen energy.

2.
Acta Pharm Sin B ; 14(2): 869-880, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38322336

RESUMO

Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.

3.
Nat Commun ; 15(1): 62, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38167266

RESUMO

Pathogen genetic diversity varies in response to environmental changes. However, it remains unclear whether plant barriers to invasion could be considered a genetic bottleneck for phytopathogen populations. Here, we implement a barcoding approach to generate a pool of 90 isogenic and individually barcoded Ralstonia solanacearum strains. We used 90 of these strains to inoculate tomato plants with different degrees of physical permeability to invasion (intact roots, wounded roots and xylem inoculation) and quantify the phytopathogen population dynamics during invasion. Our results reveal that the permeability of plant roots impacts the degree of population bottleneck, genetic diversity, and composition of Ralstonia populations. We also find that selection is the main driver structuring pathogen populations when barriers to infection are less permeable, i.e., intact roots, the removal of root physical and immune barriers results in the predominance of stochasticity in population assembly. Taken together, our study suggests that plant root permeability constitutes a bottleneck for phytopathogen invasion and genetic diversity.


Assuntos
Ralstonia solanacearum , Virulência , Ralstonia solanacearum/genética , Permeabilidade , Doenças das Plantas , Raízes de Plantas
4.
Sensors (Basel) ; 23(12)2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37420579

RESUMO

Compared with non-redundant manipulators, the self-motion of 7-DOF redundant manipulators results in an infinite number of inverse kinematics solutions for a desired end-effector pose. This paper proposes an efficient and accurate analytical solution for inverse kinematics of SSRMS-type redundant manipulators. This solution is applicable to SRS-type manipulators with the same configuration. The proposed method involves introducing an alignment constraint to restrain the self-motion and to decompose the spatial inverse kinematics problem into three independent planar subproblems simultaneously. The resulting geometric equations depend on the part of the joint angles, respectively. These equations are then computed recursively and efficiently using the sequences of (θ1,θ7), (θ2,θ6), and (θ3,θ4,θ5), generating up to sixteen sets of solutions for a given desired end-effector pose. Additionally, two complementary methods are proposed for overcoming the possible singular configuration and judging unsolvable poses. Finally, numerical simulations are conducted to investigate the performance of the proposed approach in terms of average calculation time, success rate, average position error, and the ability to plan a trajectory with singular configurations.


Assuntos
Fenômenos Biomecânicos , Movimento (Física)
5.
Br J Pharmacol ; 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37311689

RESUMO

BACKGROUND AND PURPOSE: Chaperone-mediated autophagy (CMA) is a selective type of autophagy targeting protein degradation and maintains high activity in many malignancies. Inhibition of the combination of HSC70 and LAMP2A can potently block CMA. At present, knockdown of LAMP2A remains the most specific method for inhibiting CMA and chemical inhibitors against CMA have not yet been discovered. EXPERIMENTAL APPROACH: Levels of CMA in non-small cell lung cancer (NSCLC) tissue samples were confirmed by tyramide signal amplification dual immunofluorescence assay. High-content screening was performed based on CMA activity, to identify potential inhibitors of CMA. Inhibitor targets were determined by drug affinity responsive target stability-mass spectrum and confirmed by protein mass spectrometry. CMA was inhibited and activated to elucidate the molecular mechanism of the CMA inhibitor. KEY RESULTS: Suppression of interactions between HSC70 and LAMP2A blocked CMA in NSCLC, restraining tumour growth. Polyphyllin D (PPD) was identified as a targeted CMA small-molecule inhibitor through disrupting HSC70-LAMP2A interactions. The binding sites for PPD were E129 and T278 at the nucleotide-binding domain of HSC70 and C-terminal of LAMP2A, respectively. PPD accelerated unfolded protein generation to induce reactive oxygen species (ROS) accumulation by inhibiting HSC70-LAMP2A-eIF2α signalling axis. Also, PPD prevented regulatory compensation of macroautophagy induced by CMA inhibition via blocking the STX17-SNAP29-VAMP8 signalling axis. CONCLUSIONS AND IMPLICATIONS: PPD is a targeted CMA inhibitor that blocked both HSC70-LAMP2A interactions and LAMP2A homo-multimerization. CMA suppression without increasing the regulatory compensation from macroautophagy is a good strategy for NSCLC therapy.

6.
Org Lett ; 25(22): 4208-4213, 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37249227

RESUMO

A novel visible-light-promoted selective sulfonylation and selenylation of dienes with selenosulfonates has been developed. This technology provides mild access to a wide range of sulfonyl benzo[b]azepinones and seleno-benzo[b]azepines. Preliminary mechanistic studies suggest that the sulfonylation involves a sulfonyl radical engaged cascade process, and the selenylation is accomplished through a sequential oxidation/electrophilic cyclization process. The large-scale operation and late-stage modification experiment reveal the promising utility of this protocol.


Assuntos
Azepinas , Polienos , Ciclização , Luz , Tecnologia
7.
Front Microbiol ; 14: 1186688, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37180250

RESUMO

The shikimate pathway is a general route for the biosynthesis of aromatic amino acids (AAAs) in many microorganisms. A 3-dehydroquinase, AroQ, controls the third step of the shikimate pathway that catalyzes the formation of 3-dehydroquinate from 3-dehydroshikimate via a trans-dehydration reaction. Ralstonia solanacearum harbors two 3-dehydroquinases, AroQ1 and AroQ2, sharing 52% similarity in amino acids. Here, we demonstrated that two 3-dehydroquinases, AroQ1 and AroQ2, are essential for the shikimate pathway in R. solanacearum. The growth of R. solanacearum was completely diminished in a nutriment-limited medium with the deletion of both aroQ1 and aroQ2, while substantially impaired in planta. The aroQ1/2 double mutant was able to replicate in planta but grew slowly, which was ~4 orders of magnitude less than the parent strain to proliferate to the maximum cell densities in tomato xylem vessels. Moreover, the aroQ1/2 double mutant failed to cause disease in tomato and tobacco plants, whereas the deletion of either aroQ1 or aroQ2 did not alter the growth of R. solanacearum or pathogenicity on host plants. Supplementary shikimic acid (SA), an important intermediate of the shikimate pathway, substantially restored the diminished or impaired growth of aroQ1/2 double mutant in a limited medium or inside host plants. The necessity of AroQ1 and AroQ2 on the pathogenicity of solanacearum toward host plants was partially due to insufficient SA inside host plants. Moreover, the deletion of both aroQ1 and aroQ2 significantly impaired the expression of genes for the type III secretion system (T3SS) both in vitro and in planta. Its involvement in the T3SS was mediated through the well-characterized PrhA signaling cascade and was independent of growth deficiency under nutrient-limited conditions. Taken together, R. solanacearum 3-dehydroquinases play important roles in bacterial growth, the expression of the T3SS, and pathogenicity in host plants. These results could extend our insights into the understanding of the biological function of AroQ and the sophisticated regulation of the T3SS in R. solanacearum.

8.
PLoS One ; 18(4): e0284044, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37023104

RESUMO

This paper studies the debt restructuring equilibrium decision problem composed of creditors and debt enterprises with the participation of the government and asset management companies. With the differential game, the dynamic optimization models of debt restructuring under three situations: centralized decision-making, decentralized decision-making, and Stackelberg game after introducing cost-sharing contract are constructed, respectively. The optimal equilibrium strategy of debt restructuring, the optimal trajectory of debt restructuring synergy, and the optimal profit under three decision-making situations are investigated and compared. It is found that the synergy effect and total profit of debt restructuring are the highest under centralized decision-making, and the Stackelberg game is superior to decentralized decision-making, which shows that the cost-sharing contract can achieve the coordination of overall interests, improve the debt restructuring environment, and promote the debt restructuring process. Finally, the sensitivity analysis of relevant parameters is carried out through an example, which verifies the effectiveness of the conclusion and provides the scientific basis for the government and asset management companies to participate in debt restructuring successfully.


Assuntos
Custo Compartilhado de Seguro , Governo , Contratos
9.
Cell Biosci ; 12(1): 147, 2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36064743

RESUMO

BACKGROUND: Sufficient nutrition contributes to rapid translational elongation and protein synthesis in eukaryotic cells and prokaryotic bacteria. Fast synthesis and accumulation of type III secretion system (T3SS) proteins conduce to the invasion of pathogenic bacteria into the host cells. However, the translational elongation patterns of T3SS proteins in pathogenic bacteria under T3SS-inducing conditions remain unclear. Here, we report a mechanism of translational elongation of T3SS regulators, effectors and structural protein in four model pathogenic bacteria (Pseudomonas syringae, Pseudomonas aeruginosa, Xanthomonas oryzae and Ralstonia solanacearum) and a clinical isolate (Pseudomonas aeruginosa UCBPP-PA14) under nutrient-limiting conditions. We proposed a luminescence reporter system to quantitatively determine the translational elongation rates (ERs) of T3SS regulators, effectors and structural protein under different nutrient-limiting conditions and culture durations. RESULTS: The translational ERs of T3SS regulators, effectors and structural protein in these pathogenic bacteria were negatively regulated by the nutrient concentration and culture duration. The translational ERs in 0.5× T3SS-inducing medium were the highest of all tested media. In 1× T3SS-inducing medium, the translational ERs were highest at 0 min and then rapidly decreased. The translational ERs of T3SS regulators, effectors and structural protein were inhibited by tRNA degradation and by reduced levels of elongation factors (EFs). CONCLUSIONS: Rapid translational ER and synthesis of T3SS protein need adequate tRNAs and EFs in nutrient-limiting conditions. Numeric presentation of T3SS translation visually indicates the invasion of bacteria and provides new insights into T3SS expression that can be applied to other pathogenic bacteria.

10.
Chemosphere ; 309(Pt 1): 136577, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36155016

RESUMO

Boiling is a widely adopted household tap water treatment method because of its ability to inactivate chlorine-resistant pathogenic bacteria, and to reduce certain groups of disinfection byproducts (DBPs). From a more comprehensive point of view, this study revisited the effect of boiling on four groups of 17 aliphatic DBPs and six groups of 44 aromatic DBPs in both simulated chlorinated and chloraminated tap water samples, with a special focus on the changes of total organic halogen (TOX) and cytotoxicity. Results showed that the concentrations of aliphatic DBPs substantially decreased during boiling via volatilization (trihalomethanes and chloral hydrate) and hydrolysis (haloacetamides) in chlorinated and chloraminated tap water samples. The concentrations of aromatic DBPs during boiling generally followed an increasing trend due to decarboxylation of polycarboxylic precursors in chlorinated tap water samples, and showed a first increasing and then decreasing trend in chloraminated tap water samples. A sharp decreasing of TOX occurred in the heating process of tap water samples from room temperature to 100 °C, and a relatively gentle decreasing was kept in the prolonged boiling process till 5 min. The most abundant DBP group in the tap water samples without boiling was trihalomethanes, and was replaced by haloacetic acids with boiling for 5 min. Continuous boiling for 5 min substantially reduced the cytotoxicity of chlorinated and chloraminated water samples by 52.6% and 21.3%, respectively. Reduction of cytotoxicity matched well with the reduction of TOCl (r = 0.907, P < 0.01), TOBr (r = 0.885, P < 0.01) and TOX (r = 0.905, P < 0.01), suggesting that the cytotoxicity reduction during boiling was mainly ascribed to the reduction of halogenated DBPs. Therefore, boiling of tap water to 100 °C was strongly recommended to reduce the potential health risks induced by tap water ingestion.


Assuntos
Desinfetantes , Água Potável , Poluentes Químicos da Água , Purificação da Água , Desinfecção/métodos , Halogênios/análise , Cloro , Halogenação , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Trialometanos/toxicidade , Trialometanos/análise , Hidrato de Cloral , Desinfetantes/toxicidade
11.
Front Microbiol ; 13: 945831, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36106083

RESUMO

Ralstonia solanacearum RSc2741 has been predicted as a gamma-glutamyl phosphate reductase ProA catalyzing the second reaction of proline formation from glutamate. Here, we experimentally demonstrated that proA mutants were proline auxotrophs that failed to grow in a minimal medium, and supplementary proline, but not glutamate, fully restored the diminished growth, confirming that ProA is responsible for the biosynthesis of proline from glutamate in R. solanacearum. ProA was previously identified as one of the candidates regulating the expression of genes for type three secretion system (T3SS), one of the essential pathogenicity determinants of R. solanacearum. Supplementary proline significantly enhanced the T3SS expression both in vitro and in planta, indicating that proline is a novel inducer of the T3SS expression. Deletion of proA substantially impaired the T3SS expression both in vitro and in planta even under proline-supplemented conditions, indicating that ProA plays additional roles apart from proline biosynthesis in promoting the expression of the T3SS genes. It was further revealed that the involvement of ProA in the T3SS expression was mediated through the pathway of PrhG-HrpB. Both the proA mutants and the wild-type strain grew in the intercellular spaces of tobacco leaves, while their ability to invade and colonize tobacco xylem vessels was substantially impaired, which was about a 1-day delay for proA mutants to successfully invade xylem vessels and was about one order of magnitude less than the wild-type strain to proliferate to the maximum densities in xylem vessels. It thus resulted in substantially impaired virulence of proA mutants toward host tobacco plants. The impaired abilities of proA mutants to invade and colonize xylem vessels were not due to possible proline insufficiency in the rhizosphere soil or inside the plants. All taken together, these results extend novel insights into the understanding of the biological function of ProA and sophisticated regulation of the T3SS and pathogenicity in R. solanacearum.

12.
Mol Plant Pathol ; 23(5): 679-692, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35122373

RESUMO

A syringe-like type III secretion system (T3SS) plays essential roles in the pathogenicity of Ralstonia solanacearum, which is a causal agent of bacterial wilt disease on many plant species worldwide. Here, we characterized functional roles of a CysB regulator (RSc2427) in R. solanacearum OE1-1 that was demonstrated to be responsible for cysteine synthesis, expression of the T3SS genes, and pathogenicity of R. solanacearum. The cysB mutants were cysteine auxotrophs that failed to grow in minimal medium but grew slightly in host plants. Supplementary cysteine substantially restored the impaired growth of cysB mutants both in minimal medium and inside host plants. Genes of cysU and cysI regulons have been annotated to function for R. solanacearum cysteine synthesis; CysB positively regulated expression of these genes. Moreover, CysB positively regulated expression of the T3SS genes both in vitro and in planta through the PrhG to HrpB pathway, whilst impaired expression of the T3SS genes in cysB mutants was independent of growth deficiency under nutrient-limited conditions. CysB was also demonstrated to be required for exopolysaccharide production and swimming motility, which contribute jointly to the host colonization and infection process of R. solanacearum. Thus, CysB was identified here as a novel regulator on the T3SS expression in R. solanacearum. These results provide novel insights into understanding of various biological functions of CysB regulators and complex regulatory networks on the T3SS in R. solanacearum.


Assuntos
Ralstonia solanacearum , Solanum lycopersicum , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cisteína/metabolismo , Solanum lycopersicum/microbiologia , Doenças das Plantas/microbiologia , Sistemas de Secreção Tipo III/genética , Sistemas de Secreção Tipo III/metabolismo , Virulência/genética
13.
Mol Plant Microbe Interact ; 34(11): 1228-1235, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34374557

RESUMO

Ralstonia solanacearum RSc0454 is predicted as a FAD-linked oxidase based on protein homologies, while it contains distinct domains of lactate dehydrogenase and succinate dehydrogenase. A previous study demonstrated that RSc0454 exhibits lactate dehydrogenase activity using pyruvate and NADH as substrates, and is essential for pathogenicity of R. solanacearum. Here, we genetically characterized involvement of RSc0454 on bacterial growth and expression of genes for the type III secretion system (T3SS, a pathogenicity determinant) in R. solanacearum. The RSc0454 mutant grew normally in rich medium but grew faintly in host plants, and failed to grow in minimal medium. Supplementary succinate but not lactate could substantially restore some phenotypes of RSc0454 mutants, including faint growth in host plants, diminished growth in the minimal medium, and lost pathogenicity toward host plants. Expression of T3SS genes is directly controlled by a master regulator, HrpB, and hrpB expression is positively regulated by HrpG and PrhG in parallel ways. Deletion of RSc0454 substantially reduced expression levels of hrpB and T3SS both in vitro and in planta. Moreover, RSc0454 is revealed to be required for the T3SS expression via HrpG and PrhG, although through some novel pathway, and impaired expression of these genes was not due to growth deficiency of RSc0454 mutants. RSc0454 is suggested to be important for redox balance inside cells, and supplementary NADH partially restored diminished growth of the RSc0454 mutant in the minimal medium only in the presence of succinate at some moderate concentrations, indicating that the unbalanced redox in the RSc0454 mutant might be responsible for its diminished growth in the minimal medium. Taken together, these results provide novel insights into the understanding of various biological functions of this FAD-linked oxidase RSc0454 and involvement of the redox balance on expression of the T3SS in R. solanacearum.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Ralstonia solanacearum , Proteínas de Bactérias/genética , Flavina-Adenina Dinucleotídeo , Oxirredutases , Doenças das Plantas , Ralstonia solanacearum/genética , Sistemas de Secreção Tipo III , Virulência
14.
Cell Rep ; 34(13): 108920, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33789108

RESUMO

Pseudomonas syringae, a Gram-negative plant pathogen, expresses multitudinous transcriptional regulators to control the type III secretion system (T3SS) and response to diverse environmental challenges. Although the mechanisms of virulence-associated regulators of P. syringae have been studied for decades, the overall crosstalk underlying these regulators is still elusive. Here, we identify five T3SS regulators (EnvZ-OmpR, CbrAB2, PhoPQ, PilRS, and MgrA), and find that the two-component systems EnvZ-OmpR and CbrAB2 negatively regulate the T3SS. To elucidate crosstalk between 16 virulence-associated regulators in P. syringae, we map an online intricate network called "PSRnet" (Pseudomonas syringae regulatory network) by combining the differentially expressed genes (DEGs) of these 16 regulators by RNA sequencing (RNA-seq) and their binding loci by chromatin immunoprecipitation sequencing (ChIP-seq). Consequently, we identify 238 and 153 functional genes involved in the T3SS and other virulence-related pathways in KB and MM media, respectively. Our results provide insights into the mechanism of plant infections caused by P. syringae.


Assuntos
Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Pseudomonas syringae/genética , Pseudomonas syringae/patogenicidade , Ácido Algínico/metabolismo , Proteínas de Bactérias/metabolismo , Genes Bacterianos , Movimento , Oxirredução , Ligação Proteica , Transcriptoma/genética , Sistemas de Secreção Tipo III/metabolismo , Virulência/genética
15.
Mol Plant Microbe Interact ; 33(7): 972-981, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32240066

RESUMO

RsgA plays an important role in maturation of 30S subunit in many bacteria that assists in the release of RbfA from the 30S subunit during a late stage of ribosome biosynthesis. Here, we genetically characterized functional roles of RsgA in Ralstonia solanacearum, hereafter designated RsRsgA. Deletion of R. solanacearum rsgA or rbfA resulted in distinct deficiency of 16S ribosomal RNA, significantly slowed growth in broth medium, and diminished growth in nutrient-limited medium, which are similar as phenotypes of rsgA mutants and rbfA mutants of Escherichia coli and other bacteria. Our gene-expression studies revealed that RsRsgA is important for expression of genes encoding the type III secretion system (T3SS) (a pathogenicity determinant of R. solanacearum) both in vitro and in planta. Compared with the wild-type R. solanacearum strain, proliferation of the rsgA and rbfA mutants in tobacco leaves was significantly impaired, while they failed to migrate into tobacco xylem vessels from infiltrated leaves, and hence, these two mutants failed to cause any bacterial wilt disease in tobacco plants. It was further revealed that rsgA expression was highly enhanced under nutrient-limited conditions compared with that in broth medium and RsRsgA affects T3SS expression through the PrhN-PrhG-HrpB pathway. Moreover, expression of a subset of type III effectors was substantially impaired in the rsgA mutant, some of which are responsible for R. solanacearum GMI1000 elicitation of a hypersensitive response (HR) in tobacco leaves, while RsRsgA is not required for HR elicitation of GMI1000 in tobacco leaves. All these results provide novel insights into understanding various biological functions of RsgA proteins and complex regulation on the T3SS in R. solanacearum.


Assuntos
Proteínas de Bactérias/genética , GTP Fosfo-Hidrolases/genética , Ralstonia solanacearum , Ribossomos/metabolismo , Sistemas de Secreção Tipo III , Doenças das Plantas/microbiologia , Ralstonia solanacearum/genética , Nicotiana/microbiologia , Virulência
16.
Mol Plant Pathol ; 21(6): 777-793, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32196936

RESUMO

Type IV pili (T4P) are virulence factors in various pathogenic bacteria of animals and plants that play important roles in twitching motility, swimming motility, biofilm formation, and adhesion to host cells. Here, we genetically characterized functional roles of a putative T4P assembly protein TapV (Rsc1986 in reference strain GMI1000) and its homologue Rsp0189, which shares 58% amino acid identity with TapV, in Ralstonia solanacearum. Deletion of tapV, but not rsp0189, resulted in significantly impaired twitching motility, swimming motility, and adhesion to tomato roots, which are consistent as phenotypes of the pilA mutant (a known R. solanacearum T4P-deficient mutant). However, unlike the pilA mutant, the tapV mutant produced more biofilm than the wild-type strain. Our gene expression studies revealed that TapV, but not Rsp0189, is important for expression of a type III secretion system (T3SS, a pathogenicity determinant of R. solanacearum) both in vitro and in planta, but it is T4P independent. We further revealed that TapV affected the T3SS expression via the PhcA-TapV-PrhG-HrpB pathway, consistent with previous reports that PhcA positively regulates expression of pilA and prhG. Moreover, deletion of tapV, but not rsp0189, significantly impaired the ability to migrate into and colonize xylem vessels of host plants, but there was no alteration in intercellular proliferation of R. solanacearum in tobacco leaves, which is similar to the pilA mutant. The tapV mutant showed significantly impaired virulence in host plants. This is the first report on the impact of T4P components on the T3SS, providing novel insights into our understanding of various biological functions of T4P and the complex regulatory pathway of T3SS in R. solanacearum.


Assuntos
Doenças das Plantas/imunologia , Ralstonia solanacearum/patogenicidade , Solanum lycopersicum/microbiologia , Sistemas de Secreção Tipo III/metabolismo , Fatores de Virulência/metabolismo , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Solanum lycopersicum/imunologia , Mutação , Doenças das Plantas/microbiologia , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Raízes de Plantas/imunologia , Raízes de Plantas/microbiologia , Ralstonia solanacearum/genética , Sistemas de Secreção Tipo III/genética , Virulência , Fatores de Virulência/genética
17.
Asian J Surg ; 43(1): 347-353, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31229360

RESUMO

OBJECTIVE: To compare robot-assisted surgery and conventional laparoscopy for gynecologic oncology regarding intra- and post-operative outcomes. METHODS: A retrospective study was performed on consecutive patients with gynecologic oncology from February 2014 to October 2017 at Gansu Provincial Hospital, China. Multivariable linear and logistic regression models were performed to explore the difference between two surgeries in the surgical outcomes after adjusting for potential confounders. RESULTS: 276 women were included in this study: 153 robot-assisted surgeries and 123 conventional laparoscopies. The multivariable linear regression model showed that robot-assisted surgery was longer operative time [coefficient (coef), 33.76; 95% CI, 12.47, 55.05; P = 0.002) ], higher lymph node yield (coef, 10.41; 95% CI, 7.47, 13.35; P < 0.001), shorter time to early post-operative feeding (coef, -1.09; 95% CI, -1.33, -0.84; P < 0.001) and less post-operative drainage volume (coef, -368.77; 95% CI, -542.46, -195.09; P < 0.001) than conventional laparoscopy. However, no difference was observed between the two surgeries regarding the estimated blood loss (P > 0.05). The multivariable logistic regression model showed that post-operative complications were similar between robot-assisted surgery and conventional laparoscopy (P > 0.05). CONCLUSION: Robot-assisted surgery was superior to conventional laparoscopy regarding intra- and post-operative outcomes for gynecologic oncology.


Assuntos
Neoplasias dos Genitais Femininos/cirurgia , Procedimentos Cirúrgicos em Ginecologia/métodos , Laparoscopia/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Adulto , Feminino , Humanos , Período Intraoperatório , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Período Pós-Operatório , Estudos Retrospectivos , Resultado do Tratamento
18.
Mol Plant Pathol ; 20(11): 1477-1490, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31392803

RESUMO

Ralstonia solanacearum can metabolize ferulic acid (FA) and salicylic acid (SA), two representative phenolic acids, to protect it from toxicity of phenolic acids. Here, we genetically demonstrated a novel phenolic acid decarboxylase regulator (PadR)-like regulator PrhP as a positive regulator on detoxification of SA and FA in R. solanacearum. Although the ability to degrade SA and FA enhances the infection process of R. solanacearum toward host plants, PrhP greatly contributes to the infection process besides degradation of SA and FA. Our results from the growth assay, promoter activity assay, RNA-seq and qRT-PCR revealed that PrhP plays multiple roles in the virulence of R. solanacearum: (1) positively regulates expression of genes for degradation of SA and FA; (2) positively regulates expression of genes encoding type III secretion system (T3SS) and type III effectors both in vitro and in planta; (3) positively regulates expression of many virulence-related genes, such as the flagella, type IV pili and cell wall degradation enzymes; and (4) is important for the extensive proliferation in planta. The T3SS is one of the essential pathogenicity determinants in many pathogenic bacteria, and PrhP positively regulates its expression mediated with the key regulator HrpB but through some novel pathway to HrpB in R. solanacearum. This is the first report on PadR regulators to regulate the T3SS and it could improve our understanding of the various biological functions of PadR regulators and the complex regulatory pathway on T3SS in R. solanacearum.


Assuntos
Proteínas de Bactérias/metabolismo , Sistemas de Secreção Bacterianos , Hidroxibenzoatos/metabolismo , Ralstonia solanacearum/metabolismo , Ralstonia solanacearum/patogenicidade , Ácidos Cumáricos/metabolismo , Regulação Bacteriana da Expressão Gênica , Inativação Metabólica/genética , Mutação/genética , Ralstonia solanacearum/genética , Ralstonia solanacearum/crescimento & desenvolvimento , Ácido Salicílico/metabolismo , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
19.
Arch Gynecol Obstet ; 300(1): 153-160, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31006844

RESUMO

OBJECTIVE: The aim of this study was to compare the safety and effectiveness of robotic hysterectomy (RH) with conventional laparoscopic hysterectomy (LH) for the treatment of cervical cancer using multivariate regressions. METHODS: We designed a retrospective single-center study and consecutively collected patients with cervical cancer from February 2014 to October 2017. Data extraction was performed by two independent researchers. The surgical outcomes include operative time, estimated blood loss, number of lymph nodes, time to first flatus, time to a full diet, time to remove drainage tube, length of hospital stay, and postoperative complication. RESULTS: A total of 152 patients with cervical cancer were collected in our study including 92 patients who underwent RH and 60 patients who underwent LH. Both groups have similar characteristics. The RH group showed shorter operative time (Coe - 42.89; 95% CI - 74.39 to 11.39; P = 0.008) and more number of lymph nodes (Coe 6.06; 95% CI 2.46-9.66; p = 0.001) than the LH group. As for the postoperative parameters, the RH group showed shorter time to remove drainage tube (Coe - 0.89; 95% CI -1.62 to -0.15; p = 0.019) and length of hospital stay (Coe - 6.40; 95% CI - 10.19 to - 2.95; p = 0.001). No significant difference was found between the groups in estimated blood loss (Coe 34.64; 95% CI - 33.08 to 102.37; p = 0.314), time to first flatus (Coe 0.11; 95% CI - 0.38 to 0.61; p = 0.652), time to a full diet (Coe - 0.24; 95% CI - 0.54 to 0.06, p = 0.118), and postoperative complication (OR 0.84; 95% CI 0.35-1.98; p = 0.685). CONCLUSION: The results from this study suggest that RH is safe and effective as LH but robotic surgery significantly contributed to the feasibility of alternative treatment options for cervical cancer patients.


Assuntos
Histerectomia/métodos , Laparoscopia/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Neoplasias do Colo do Útero/cirurgia , China , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias do Colo do Útero/patologia
20.
Cell Immunol ; 331: 100-109, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29909072

RESUMO

Dendritic cells (DCs) contain heterogeneous populations, with classical DCs developed at steady state and monocyte-derived DCs mobilized under inflammatory conditions, although their total numbers in vivo are scares. To obtain enough quantity for immunological study or clinical application, we have previously established that bone marrow-derived DCs in the presence of Flt-3L (FL-DCs) or GM-CSF (GM-DCs) in vitro are equivalent to the steady state DCs and inflammatory DCs in vivo respectively. What difference, however, exists between these two most commonly used culture systems in DC functions and survival, and how does it correlate to the division of works by their corresponding counterparts in vivo remain ill-defined. In this study, we found that GM-DCs of inflammatory nature were more phagocytic, potent at inducing Th2 and Th17 differentiation, and had longer survival rate, whereas FL-DCs of steady state characters were stronger T cell activator and better at directing Th1 differentiation. Mechanistically, NO production induced by the LPS-activated GM-DCs could partly explain for their failure to improve T cell proliferation, and the distinct T cell differentiation profiles and viability demonstrated by the two types of DCs were underpinned by their preferential secretion of T cell polarizing cytokines and expression of anti-apoptotic genes. Such disparate functionalities and survival potentials of steady state and inflammatory DCs in vitro fit in well with their respective roles in vivo in particular immunological settings and have serious implications in translational applications.


Assuntos
Células da Medula Óssea/imunologia , Diferenciação Celular/imunologia , Citocinas/imunologia , Células Dendríticas/imunologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/imunologia , Células Cultivadas , Citocinas/metabolismo , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Ativação Linfocitária/imunologia , Proteínas de Membrana/farmacologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA