RESUMO
The condensation of acetyl-CoA with malonyl-acyl carrier protein (ACP) by ß-ketoacyl-ACP synthase III (KAS III, FabH) and decarboxylation of malonyl-ACP by malonyl-ACP decarboxylase are the two pathways that initiate bacterial fatty acid synthesis (FAS) in Escherichia coli. In addition to these two routes, we report that Pseudomonas putida F1 ß-ketoacyl-ACP synthase I (FabB), in addition to playing a key role in fatty acid elongation, also initiates FAS in vivo. We report that although two P. putida F1 fabH genes (PpfabH1 and PpfabH2) both encode functional KAS III enzymes, neither is essential for growth. PpFabH1 is a canonical KAS III similar to E. coli FabH whereas PpFabH2 catalyzes condensation of malonyl-ACP with short- and medium-chain length acyl-CoAs. Since these two KAS III enzymes are not essential for FAS in P. putida F1, we sought the P. putida initiation enzyme and unexpectedly found that it was FabB, the elongation enzyme of the oxygen-independent unsaturated fatty acid pathway. P. putida FabB decarboxylates malonyl-ACP and condenses the acetyl-ACP product with malonyl-ACP for initiation of FAS. These data show that P. putida FabB, unlike the paradigm E. coli FabB, can catalyze the initiation reaction in FAS.
Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase , Pseudomonas putida , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/genética , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Proteína de Transporte de Acila/metabolismo , Escherichia coli/metabolismo , Elongases de Ácidos Graxos/genética , Elongases de Ácidos Graxos/metabolismo , Ácidos Graxos , Glicogênio Sintase , Pseudomonas putida/genética , Pseudomonas putida/metabolismoRESUMO
The genomes of the best-studied pseudomonads, Pseudomonas aeruginosa and Pseudomonas putida, which share 85% of the predicted coding regions, contain a fabA fabB operon (demonstrated in P. aeruginosa, putative in P. putida). The enzymes encoded by the fabA and fabB genes catalyze the introduction of a double bond into a 10-carbon precursor which is elongated to the 16:1Δ9 and 18:1Δ11 unsaturated fatty acyl chains required for functional membrane phospholipids. A detailed analysis of transcription of the P. putida fabA fabB gene cluster showed that fabA and fabB constitute an operon and disclosed an unexpected and essential fabB promoter located within the fabA coding sequence. Inactivation of the fabA fabB operon fails to halt the growth of P. aeruginosa PAO1 but blocks growth of P. putida F1 unless an exogenous unsaturated fatty acid is provided. We report that the asymmetry between these two species is due to the P. aeruginosa PAO1 desA gene which encodes a fatty acid desaturase that introduces double bonds into the 16-carbon acyl chains of membrane phospholipids. Although P. putida F1 encodes a putative DesA homolog that is 84% identical to the P. aeruginosa PAO1, the protein fails to provide sufficient unsaturated fatty acid synthesis for growth when the FabA FabB pathway is inactivated. We report that the P. putida F1 DesA homolog can functionally replace the P. aeruginosa DesA. Hence, the defect in P. putida F1 desaturation is not due to a defective P. putida F1 DesA protein but probably to a weakly active component of the electron transfer process.
Assuntos
Ácidos Graxos Insaturados , Fosfolipídeos , Ácido Graxo Sintase Tipo II/metabolismo , Ácidos Graxos Insaturados/metabolismo , Regiões Promotoras GenéticasRESUMO
The Enterococcus faecalis genome contains two enoyl-ACP reductases genes, fabK and fabI, which encode proteins having very different structures. Enoyl-ACP reductase catalyzes the last step of the elongation cycle of type II fatty acid synthesis pathway. The fabK gene is located within the large fatty acid synthesis operon whereas fabI is located together with two genes fabN and fabO required for unsaturated fatty acid synthesis. Prior work showed that FabK is weakly expressed due to poor translational initiation and hence virtually all the cellular enoyl ACP reductase activity is that encoded by fabI. Since FabK is a fully functional enzyme, the question is why FabI is an essential enzyme. Why not increase FabK activity? We report that overproduction of FabK is lethal whereas FabI overproduction only slows the growth and is not lethal. In both cases, normal growth is restored by the addition of oleic acid, an unsaturated fatty acid, to the medium indicating that enoyl ACP reductase overproduction disrupts unsaturated fatty acid synthesis. We report that this is due to competition with FabO, a putative 3-ketoacyl-ACP synthase I via FabN, a dehydratase/isomerase providing evidence that the enoyl-ACP reductase must be matched to the unsaturated fatty acid synthetic genes. FabO has been ascribed the same activity as E. coli FabB and we report in vitro evidence that this is the case, whereas FabN is a dehydratase/isomerase, having the activity of E. coli FabA. However, FabN is much larger than FabA, it is a hexamer rather than a dimer like FabA.
Assuntos
Enoil-(Proteína de Transporte de Acila) Redutase (NADH) , Enterococcus faecalis , Enterococcus faecalis/metabolismo , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/genética , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/metabolismo , Escherichia coli/metabolismo , Ácidos Graxos Insaturados , Hidroliases/genéticaRESUMO
Pseudomonas aeruginosa PAO1 has two aerobic pathways for synthesis of unsaturated fatty acids (UFAs), DesA and DesB plus the oxygen independent FabAB pathway. The DesA desaturase acts on saturated acyl chains of membrane phospholipid bilayers whereas the substrates of the DesB desaturase are thought to be long chain saturated acyl-CoA thioesters derived from exogeneous saturated fatty acids that are required to support DesB-dependent growth. Under suitable aerobic conditions either of these membrane-bound desaturates can support growth of P. aeruginosa ∆fabA strains lacking the oxygen independent FabAB pathway. We previously studied function of the desA desaturase of P. putida in a P. aeruginosa ∆fabA ∆desA strain that required supplementation with a UFA for growth and noted bypass suppression of the P. aeruginosa ∆fabA ∆desA strain that restored UFA synthesis. We report three genes encoding lipid metabolism proteins that give rise to suppressor strains that bypass loss of the DesA and oxygen independent FabAB pathways.
Assuntos
Ácidos Graxos , Pseudomonas aeruginosa , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Oxigênio/metabolismoRESUMO
The self-reconfigurable modular robotic system is a class of robots that can alter its configuration by rearranging the connectivity of their component modular units. The reconfiguration deformation planning problem is to find a sequence of reconfiguration actions to transform one reconfiguration into another. In this paper, a hybrid reconfiguration deformation planning algorithm for modular robots is presented to enable reconfiguration between initial and goal configurations. A hybrid algorithm is developed to decompose the configuration into subconfigurations with maximum commonality and implement distributed dynamic mapping of free vertices. The module mapping relationship between the initial and target configurations is then utilized to generate reconfiguration actions. Simulation and experiment results verify the effectiveness of the proposed algorithm.
RESUMO
Enterococcus faecalis encodes two proteins, AcpA and AcpB, having the characteristics of acyl carrier proteins (ACPs). We report that the acpA gene located in the fatty acid synthesis operon is essential for fatty acid synthesis and the ΔacpA strain requires unsaturated fatty acids for growth. The ΔacpA strain could be complemented by a plasmid carrying a wild-type acpA gene, but not by a plasmid carrying a wild-type acpB gene. Substitution of four AcpA residues for those of AcpB resulted in a protein that modestly complemented the ΔacpA strain and restored fatty acid synthesis, although the acyl chains synthesized were unusually short. IMPORTANCE Enterococcus faecalis, as well as related species, has two genes-acpA and acpB-encoding putative acyl carrier proteins (ACPs). It has been assumed that AcpA is essential for fatty acid synthesis whereas AcpB is involved utilization of environmental fatty acids. We report here the first experimental test of the essentiality of acpA and show that it is indeed an essential gene that cannot be replaced by acpB.
Assuntos
Proteína de Transporte de Acila/metabolismo , Proteínas de Bactérias/metabolismo , Enterococcus faecalis , Enterococcus faecalis/metabolismo , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados , ÓperonRESUMO
The Pseudomonas putida F1 genome contains five genes annotated as encoding 3-ketoacyl-acyl carrier protein (ACP) synthases. Four are annotated as encoding FabF (3-ketoacyl-ACP synthase II) proteins, and the fifth is annotated as encoding a FabB (3-ketoacyl-ACP synthase I) protein. Expression of one of the FabF proteins, FabF2, is cryptic in the native host and becomes physiologically important only when the repressor controlling fabF2 transcription is inactivated. When derepressed, FabF2 can functionally replace FabB, and when expressed from a foreign promoter, had weak FabF activity. Complementation of Escherichia coli fabB and fabF mutant strains with high expression showed that P. putida fabF1 restored E. coli fabF function, whereas fabB restored E. coli fabB function and fabF2 restored the functions of both E. coli fabF and fabB. The P. putida ΔfabF1 deletion strain was almost entirely defective in synthesis of cis-vaccenic acid, whereas the ΔfabB strain is an unsaturated fatty acid (UFA) auxotroph that accumulated high levels of spontaneous suppressors in the absence of UFA supplementation. This was due to increased expression of fabF2 that bypasses loss of fabB because of the inactivation of the regulator, Pput_2425, encoded in the same operon as fabF2. Spontaneous suppressor accumulation was decreased by high levels of UFA supplementation, whereas competition by the P. putida ß-oxidation pathway gave increased accumulation. The ΔfabB ΔfabF2 strain is a stable UFA auxotroph indicating that suppressor accumulation requires FabF2 function. However, at low concentrations of UFA supplementation, the ΔfabF2 ΔPput_2425 double-mutant strain still accumulated suppressors at low UFA concentrations.
Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Ácidos Graxos Insaturados/biossíntese , Pseudomonas putida/metabolismo , Teste de Complementação GenéticaRESUMO
Reliable forecast of municipal solid waste (MSW) generation is crucial for sustainable and efficient waste management. Big data analysis is a novel method to forecast MSW more accurately. Thus, this study employs five kinds of supervised machine learning approaches including linear regression, polynomial regression, support vector machine, random forest, and extreme gradient boosting (XGBoost) to examine their forecast performances. China's MSW generation from 2020 to 2060 under five shared socioeconomic pathways (SSPs) is further predicted and the mechanisms between MSW generation and socioeconomic features are explored. Results show that population and GDP are two dominant indicators in MSW prediction, and XGBoost model is proved to be effective in MSW forecast. MSW generation of China in 2060 is estimated to be 464-688 megatons under different SSPs scenarios, about four to six times of that in 2000. SSP3 that has the most population, least GDP and the highest climate change challenges is the only scenario showing a potential of MSW peak during the study period. The key for MSW increase is mainly the increase of per capita MSW caused by GDP. Finally, several policy recommendations are raised to reduce the overall MSW generation.
Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , China , Cidades , Aprendizado de Máquina , Eliminação de Resíduos/métodos , Fatores Socioeconômicos , Resíduos Sólidos/análiseRESUMO
Overcapacity is regarded as an inevitable problem for rapid economic developing countries like China, which also causes serious adverse impacts on the environment and public health. However, few studies have quantified the overcapacity feature and corresponding co-benefit from de-capacity policy. To fill such research gaps, this study constructed a comprehensive assessment model by combining the Data Envelopment Analysis (DEA) model, the GAINS-China (Greenhouse gas - Air pollution Interactions and Synergies) model, and a meta-analysis and health impact assessment module, to measure the capacity utilization rate of 41 industrial sectors in 31 Chinese provinces and forecast the environmental and health co-benefits from de-capacity policy in 2050. Results showed that the capacity utilization rate of China's industry is 64.13% in 2018, which is much lower than the threshold value of 75%, indicating serious overcapacity in China's industry. Capacity utilization rates of light industries are higher (around 70%) than heavy industries (50%-60%), and the capacity utilization rate in East and South-Central China is higher (70%-96%) than West China (below 40%). Under a de-capacity scenario in 2050, China's CO2 and PM2.5 emissions are reduced by 1.05 billion tons (9.6%) and 57.8 kilotons (5.8%), respectively. This reduction in PM2.5 emissions results in a substantial health co-benefit, reducing national premature mortality cases by approximately 792,100 (1.6%). Finally, it is recommended that de-capacity priority be given to industries with low capacity utilization rate, as well as regions with intensive heavy industry or high levels of greenhouse gas emissions, severe air pollution, and dense population.
Assuntos
Poluição do Ar , China , Saúde Ambiental , MetalurgiaRESUMO
Both Enterococcus faecalis and Escherichia coli can undergo abrupt temperature transitions in nature. E. coli changes the composition of its phospholipid acyl chains in response to shifts growth temperature. This is mediated by a naturally temperature sensitive enzyme, FabF (3-ketoacyl-acyl carrier protein synthase II), that elongates the 16 carbon unsaturated acyl chain palmitoleate to the 18 carbon unsaturated acyl chain, cis-vaccenate. FabF is more active at low temperatures resulting in increased incorporation of cis-vaccenoyl acyl chains into the membrane phospholipids. This response to temperature is an intrinsic property of FabF and does not require increased synthesis of the enzyme. We report that the FabF of the very divergent bacterium, E. faecalis, has properties very similar to E. coli FabF and is responsible for changing E. faecalis membrane phospholipid acyl chain composition in response to temperature. Moreover, expression E. faecalis FabF in an E. coli ∆fabF strain restores temperature regulation to the E. coli strain.
Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase , Escherichia coli , Enterococcus faecalis/genética , Escherichia coli/genética , Ácidos Graxos , Fosfolipídeos , TemperaturaRESUMO
BACKGROUND: Eczema is a chronic inflammatory disease associated with impaired quality of life. We identified indoor environmental risk factors, to provide strong evidence for the prevention and control of eczema in preschool children. METHODS: Using a cross-sectional study with stratified random cluster sampling, we conducted a self-administered questionnaire survey among 8153 parents of children aged 2-8 years in 60 kindergartens in six districts of Urumqi city during August 2019. RESULTS: Among 8153 preschool children, 12.0% of the children have been diagnosed with eczema. Multivariate logistic regression analysis showed that caesarean section (odds ratio [OR] = 1.18, 95% confidence interval [CI]: 1.03-1.36), being an only child (OR = 1.36, 95% CI: 1.18-1.57), presence of mould or moisture in the mother's home before pregnancy (OR = 1.53, 95% CI: 1.17-2.00), presence of flies or mosquitoes in the dwelling currently (OR = 1.31, 95% CI: 1.10-1.55), pets kept in the child's home currently (OR = 1.23, 95% CI: 1.01-1.51), presence of pets during child's first year (OR = 1.45, 95% CI: 1.14-1.85), and family history of eczema (OR = 3.53, 95% CI: 2.98-4.19) are the risk factors for the development of eczema, whereas ethnicity other than the Han Chinese (OR = 0.77, 95% CI: 0.61-0.96) is a protective factor for eczema. CONCLUSION: Preschool children in Urumqi are at a high risk of eczema, particularly those of the Han Chinese ethnicity. Parents should be attentive to the indoor living environment of children and take actions to reduce indoor humidity, pest control and elimination, and avoid raising pets to reduce the risk of development of eczema in children.
Assuntos
Cesárea , Eczema , Animais , Pré-Escolar , Estudos Transversais , Eczema/epidemiologia , Eczema/etiologia , Feminino , Humanos , Gravidez , Prevalência , Qualidade de Vida , Fatores de RiscoRESUMO
The novel marine pyrrole alkaloid neolamellarin A derived from sponge has been shown to inhibit hypoxia-induced HIF-1 activity. In this work, we designed and synthesized neolamellarin A and its series of derivatives by a convergent synthetic strategy. The HIF-1 inhibitory activity and cytotoxicity of these compounds were evaluated in Hela cells by dual-luciferase reporter gene assay and MTT assay, respectively. The results showed that neolamellarin A 1 (IC50â¯=â¯10.8⯱â¯1.0⯵M) and derivative 2b (IC50â¯=â¯11.9⯱â¯3.6⯵M) had the best HIF-1 inhibitory activity and low cytotoxicity. Our SAR research focused on the effects of key regions aliphatic carbon chain length, aromatic ring substituents and C-7 substituent on biological activity, providing a basis for the subsequent research on the development of novel pyrrole alkaloids as HIF-1 inhibitors and design of small molecule probes for target protein identification.
Assuntos
Antineoplásicos/farmacologia , Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Pirróis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Estrutura Molecular , Pirróis/síntese química , Pirróis/química , Relação Estrutura-AtividadeRESUMO
In this paper, the mechanism of orobanone analogues formation via aromatization rearrangement of curcumol was minutely explored. Aromatization of curcumol with acetone under acidic condition was selected as the model reaction. The formation of a stable aromatic system was the driving force for this reaction. Based on the model reaction, other four new orobanone analogues were prepared through curcumol reacting with different carbonyl compounds. The results showed that the stability of carbocation, which was generated from the carbonyl compounds, and the steric hindrance were main factors affecting the aromatization. We also synthesized the analogue of aromaticane B using compound 2. In vitro anti-proliferative activity of some derivatives were tested by MTT assay. Two derivatives showed weak anti-tumor effect on two cancer cell lines (HepG2 and MCF7) under normoxia. Four orobanone analogue 2, 5, 6 and 9 significantly inhibited hypoxia-induced HIF-1 luciferase reporter activity in HeLa cells with the IC50 values of 13.6, 6.6, 2.4 and 18.2⯵M, respectively.
Assuntos
Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Sesquiterpenos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Hipóxia Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Fator 1 Induzível por Hipóxia/genética , Sesquiterpenos/síntese química , Transcrição Gênica/efeitos dos fármacosRESUMO
BACKGROUND: Semaphorin 5A has been linked to tumor growth, invasion, and metastasis in pancreatic cancer. However, the role of semaphorin 5A in cervical cancer is not known. Our aim is to investigate the prognostic value of semaphorin 5A and its potential role in lymphangiogenesis and invasion in cervical cancer. METHODS: In this study, pathological features and clinical data of 232 cervical cancer patients were retrospectively reviewed. Semaphorin 5A protein and mRNA expression was detected by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction, respectively. In vitro, we determined the role and mechanistic pathways of semaphorin 5A in tumor progression in cervical carcinoma cell lines. RESULTS: Semaphorin 5A expression was significantly higher in stage IIb tumors than in stage Ia, Ib, and IIa tumors. High semaphorin 5A expression was significantly associated with pelvic lymph node metastasis, lymphovascular permeation, and poor survival. Semaphorin 5A induced lymphangiogenesis through a plexin-B/Met/vascular endothelial growth factor-C pathway. Semaphorin 5A also increased cervical cancer cell invasion by stimulating the expression and activity of matrix metalloproteinase-2 and matrix metalloproteinase-9 via PI3K/AKT and plexin-B3. CONCLUSION: Our findings indicate that semaphorin 5A may represent a poor prognostic biomarker and anti-metastasis therapeutic target in cervical cancer.
RESUMO
BACKGROUND: Recent reports showed BCL11A may be causatively involved in myeloid leukemia. This study investigated the relationship between BCL11A expression levels and adult acute myeloid leukemia patient characteristics as well as clinical outcomes. METHODS: RT-PCR was employed to detect BCL11A gene expression levels in 80 patients with acute myeloid leukemia. RESULTS: Median BCL11A expression levels of 80 AML bone marrow samples were found to be higher than the control group (0.039 vs. 0.014, p < 0.005). Patients with low BCL11A expression levels had a significantly higher CR (complete remission) rate compared with patients with high BCL11A expression levels (90% vs. 53%, p < 0.005). Moreover, the median OS (overall survival) in patients with low BCL11A expression (268 d) was also longer than that in patients with high BCL11A expression (101.5 d) (p < 0.05). No significant difference was observed between the high and low BCL11A groups with respect to white blood cells, haemoglobin, platelet count, French-American-Britain (FAB) subtypes, percentage of blasts in bone marrow, peripheral blood, cytogenetic risk groups, and CD34 expression. CONCLUSIONS: Adult acute myeloid leukemia had a higher BCL11A expression level. High BCL11A expression level was correlated with lower CR rate and shorter OS, suggesting that BCL11A expression could potentially be used as a prognosis indicator.
Assuntos
Biomarcadores Tumorais/genética , Proteínas de Transporte/genética , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Adolescente , Adulto , Idoso , Exame de Medula Óssea , Estudos de Casos e Controles , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/terapia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reação em Cadeia da Polimerase em Tempo Real , Indução de Remissão , Proteínas Repressoras , Fatores de Risco , Análise de Sobrevida , Resultado do Tratamento , Regulação para Cima , Adulto JovemRESUMO
This study evaluates the PM2.5 pollution-related health impacts on the national and provincial economy of China using a computable general equilibrium (CGE) model and the latest nonlinear exposure-response functions. Results show that the health and economic impacts may be substantial in provinces with a high PM2.5 concentration. In the WoPol scenario without PM2.5 pollution control policy, we estimate that China experiences a 2.00% GDP loss and 25.2 billion USD in health expenditure from PM2.5 pollution in 2030. In contrast, with control policy in the WPol scenario, a control investment of 101.8 billion USD (0.79% of GDP) and a gain of 1.17% of China's GDP from improving PM2.5 pollution are projected. At the provincial level, GDP loss in 2030 in the WoPol scenario is high in Tianjin (3.08%), Shanghai (2.98%), Henan (2.32%), Beijing (2.75%), and Hebei (2.60%) and the top five provinces with the highest additional health expenditure are Henan, Sichuan, Shandong, Hebei, and Jiangsu. Controlling PM2.5 pollution could bring positive benefits in two-thirds of provinces. Tianjin, Shanghai, Beijing, Henan, Jiangsu, and Hebei experience most benefits from PM2.5 pollution control as a result of a higher PM2.5 pollution and dense population distribution. Conversely, the control investment is higher than GDP gain in some underdeveloped provinces, such as Ningxia, Guizhou, Shanxi, Gansu, and Yunnan.
Assuntos
Poluição Ambiental , Modelos Teóricos , Pequim , China , Humanos , Material ParticuladoRESUMO
In Xanthomonas campestris pv. campestris (Xcc), the proteins encoded by the rpf (regulator of pathogenicity factor) gene cluster produce and sense a fatty acid signal molecule called diffusible signalling factor (DSF, 2(Z)-11-methyldodecenoic acid). RpfB was reported to be involved in DSF processing and was predicted to encode an acyl-CoA ligase. We report that RpfB activates a wide range of fatty acids to their CoA esters in vitro. Moreover, RpfB can functionally replace the paradigm bacterial acyl-CoA ligase, Escherichia coliâ FadD, in the E. coli ß-oxidation pathway and deletion of RpfB from the Xcc genome results in a strain unable to utilize fatty acids as carbon sources. An essential RpfB function in the pathogenicity factor pathway was demonstrated by the properties of a strain deleted for both the rpfB and rpfC genes. The ΔrpfB ΔrpfC strain grew poorly and lysed upon entering stationary phase. Deletion of rpfF, the gene encoding the DSF synthetic enzyme, restored normal growth to this strain. RpfF is a dual function enzyme that synthesizes DSF by dehydration of a 3-hydroxyacyl-acyl carrier protein (ACP) fatty acid synthetic intermediate and also cleaves the thioester bond linking DSF to ACP. However, the RpfF thioesterase activity is of broad specificity and upon elimination of its RpfC inhibitor RpfF attains maximal activity and its thioesterase activity proceeds to block membrane lipid synthesis by cleavage of acyl-ACP intermediates. This resulted in release of the nascent acyl chains to the medium as free fatty acids. This lack of acyl chains for phospholipid synthesis results in cell lysis unless RpfB is present to counteract the RpfF thioesterase activity by catalysing uptake and activation of the free fatty acids to give acyl-CoAs that can be utilized to restore membrane lipid synthesis. Heterologous expression of a different fatty acid activating enzyme, the Vibrio harveyi acyl-ACP synthetase, replaced RpfB in counteracting the effects of high level RpfF thioesterase activity indicating that the essential role of RpfB is uptake and activation of free fatty acids.
Assuntos
Coenzima A Ligases/metabolismo , Ácidos Graxos/metabolismo , Xanthomonas campestris/enzimologia , Acil Coenzima A/metabolismo , Proteínas de Bactérias/metabolismo , Carbono-Enxofre Ligases/metabolismo , Coenzima A Ligases/genética , Coenzima A Ligases/isolamento & purificação , Difusão , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Teste de Complementação Genética , Enzimas Multifuncionais/metabolismo , Família Multigênica , Mutação , Oxirredução , Doenças das Plantas/microbiologia , Transdução de Sinais/genética , Especificidade por Substrato , Tioléster Hidrolases/metabolismo , Xanthomonas campestris/genética , Xanthomonas campestris/crescimento & desenvolvimento , Xanthomonas campestris/patogenicidadeRESUMO
A sensing technique called a dual-path distributed Brillouin sensor (D-DBS) is proposed for simultaneous measurement of pressure and temperature. The D-DBS consists of a pair of sensing fibers, which are designed with different pressure and temperature coefficients of Brillouin frequency shift (BFS) by taking advantage of different fiber coatings. The highlight of this technique is to resolve the problem of the pressure-temperature cross sensitivity of the BFS within the optical fibers. The validation experiment shows satisfactory results, and it is indicated theoretically that the expected precisions of pressure and temperature are less than 0.25 MPa and 0.28°C, respectively.
RESUMO
Treatment optimization in acute myeloid leukemia requires the accurate assignment of patients at diagnosis to specific risk groups to guide subsequent risk-adapted treatment stratification. In this study, we have evaluated the impact of expression of the gene BAALC in conjunction with MDR1 in AML with intermediate cytogenetic risk group to more precisely define risk assessment. Low MDR1/high BAALC, high MDR1/low BAALC, and high MDR1/high BAALC expressers demonstrated a similar clinical outcome with CR rate being 68.75-75% and relapse rate being 40-50% and therefore could be considered as a "combined group". In contrast, low expression of both BAALC and MDR1 identifies an intermediate cytogenetic risk group a distinctly favorable outcome, with higher CR rate being 93.3%, lower relapse rate being 7.1%, and longer OS being 50.3% than that of the "combined group". Moreover, low MDR1/low BAALC expressers in the intermediate cytogenetic risk group also demonstrated a comparable clinical outcome with patients in the favorable-risk group. Thus low MDR1/low BAALC expression identifies a subgroup of intermediate cytogenetic risk AML patients with a remarkably good long-term outcome achieved by chemotherapy alone.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Expressão Gênica , Leucemia Mieloide Aguda/genética , Proteínas de Neoplasias/genética , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Medula Óssea/patologia , Feminino , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/terapia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Avaliação de Resultados da Assistência ao Paciente , Prognóstico , Adulto JovemRESUMO
BACKGROUND: Disulfiram (DS), an anti-alcoholism drug, demonstrates strong antitumor activity in a copper (Cu)-dependent manner. This study investigates the cytotoxicity of DS/Cu complex in lymphoid malignant cell lines in vitro and in vivo. METHOD: Raji cells were subjected to different treatments and thereafter MTT assay, flow cytometry were used to determine IC50 and apoptotic status. We also tested the cytotoxicity of DS/Cu in acute lymphoblastic leukemia cell line Molt4 in vitro. In vivo experiments were also performed to demonstrate the anticancer efficacy of DS/Cu in Raji cells xenografted nude mice. RESULTS: In combination with a low concentration (1 µM) of Cu2+, DS induced cytotoxicity in Raji cells with an IC50 of 0.085 ± 0.015 µM and in Molt4 cells with an IC50 of 0.435 ± 0.109 µM. The results of our animal experiments also showed that the mean tumor volume in DS/Cu-treated mice was significantly smaller than that in DS or control group, indicating that DS/Cu inhibits the proliferation of Raji cells in vivo. DS/Cu also induced apoptosis in 2 lymphoid malignant cell lines. After exposure to DS (3.3 µM)/Cu (1 µM) for 24 hours, apoptosis was detected in 81.03 ± 7.91% of Raji cells. DS/Cu induced significant apoptosis in a concentration-dependent manner with the highest apoptotic proportion (DS/Cu: 89.867 ± 4.69%) at a concentration of 2 µM in Molt4 cells. After 24 h exposure, DS/Cu inhibits Nrf2 expression. Flow cytometric analysis shows that DS/Cu induced ROS generation. DS/Cu induced phosphorylation of JNK and inhibits p65 expression as well as Nrf2 expression both in vitro and in vivo. N-acetyl-L-cysteine (NAC), an antioxidant, can partially attenuate DS/Cu complex-induced apoptosis and block JNK activation in vitro. In addition, NAC is able to restore Nrf2 nuclear translocation and p65 expression. CONCLUSION: Our study manifests that DS/Cu complex targets lymphoid malignant cells in vitro and in vivo. Generation of ROS might be one of core steps in DS/Cu induced apoptosis. Moreover, ROS-related activation of JNK pathway and inhibition of NF-κB and Nrf2 may also contribute to the DS/Cu induced apoptosis.