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BACKGROUND AND AIMS: We investigated the ideal acetic acid (AA) concentration for AA-enhanced narrow-band imaging magnifying endoscopy (ANBI-ME) in the diagnosis of superficial colorectal neoplasms and evaluated its clinical efficacy. METHODS: During the exploratory phase, we investigated 4 concentrations (1.5%, 2.25%, 3.0%, and 4.5%) in rotation by performing ANBI-ME on 50 superficial colorectal neoplasms at each concentration. A favorable AA concentration was determined by evaluating the diagnostic accuracy, AA whitening duration (AD), peristalsis, and bleeding after endoscopic resection. In the validation phase, we assessed interobserver agreements for ANBI-ME with the determined AA concentration and intermethodologic agreements between that and subsequently conducted crystal violet-stained magnifying endoscopy (CV-ME) with the exploratory set and 98 additional patients. RESULTS: The diagnostic accuracies were 89.3% (42/47) for 1.5% AA, 92.0% (46/50) for 2.25% AA, 96.8% (61/63) for 3.0% AA, and 97.8% (46/47) for 4.5% AA, with no significant difference (P = .26). A significant positive correlation was observed between AA concentration and AD (P < .001). No significant differences in hyperperistalsis or post-resection bleeding were observed. The optimal AA concentration was determined to be 4.5%. In the validation analysis, the accuracy rates were 72.4% (105/145) with the use of AMBI-ME and 68.3% (99/145) with the use of CV-ME (P = .43). Strong agreements were noted between observers (κ: 0.87 for ANBI-ME, 0.83 for CV-ME) and between the methods (κ: 0.87 and 0.81 for each observer). CONCLUSIONS: For diagnosing colorectal lesions, an AA concentration of 4.5% in ANBI-ME was safe and effective. Its diagnostic performance was similar to CV-ME, and future large-sample studies may confirm its potential as a reliable alternative endoscopic diagnostic method.
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Although esophageal cancers invading the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic resection (ER) are associated with a risk of lymph node metastasis, details of metastatic recurrence after additional treatment remain unknown. We aimed to identify the risk factors for metastatic recurrence and recurrence patterns in patients receiving additional treatment after ER for esophageal cancer. Between 2006 and 2017, patients with pT1a-MM/pT1b-SM esophageal cancer who underwent ER with additional treatment (esophagectomy, chemoradiotherapy [CRT], and radiation therapy) at 21 institutions in Japan were enrolled. We evaluated the risk factors for metastatic recurrence after ER with additional treatment. Subsequently, the rate and pattern (locoregional or distant) of metastatic recurrence were investigated for each additional treatment. Of the 220 patients who received additional treatment, 57, 125, and 38 underwent esophagectomy, CRT, and radiation therapy, respectively. In the multivariate analysis, lymphatic invasion was the sole risk factor for metastatic recurrence after additional treatment (hazard ratio, 3.50; P = 0.029). Although the risk of metastatic recurrence with additional esophagectomy was similar to that with CRT (hazard ratio, 1.01; P = 0.986), the rate of locoregional recurrence tended to be higher with additional esophagectomy (80.0% (4/5) vs. 36.4% (4/11)), leading to a better prognosis in patients with metastatic recurrence after additional esophagectomy than CRT (survival rate, 80.0% (4/5) vs. 9.1% (1/11)). Patients with lymphatic invasion have a high risk of metastatic recurrence after ER with additional treatment for pT1a-MM/pT1b-SM esophageal cancer. Additional esophagectomy may result in a better prognosis after metastatic recurrence.
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OBJECTIVES: Clinical outcomes of endoscopic submucosal dissection (ESD) for esophageal squamous cell carcinoma (ESCC) with esophageal varices (EVs) are obscure. We aimed to elucidate the clinical outcomes of ESD for ESCC with EVs in a multicenter, retrospective study. METHODS: We established a retrospective cohort of 30 patients with ESCC complicating EVs, who underwent ESD at 11 Japanese institutions. Rates of en bloc resection and R0 resection, procedure time, and adverse events were evaluated as indicators of the feasibility and safety of ESD. Additional treatment, recurrence, and metastasis of the lesions were evaluated as indicators of the long-term efficacy of ESD. RESULTS: Portal hypertension was caused by cirrhosis, of which alcohol was the most common cause. En bloc resection was achieved in 93.3% and R0 resection in 80.0% of the patients. The median procedure time was 92 min. Adverse events included a case of uncontrolled intraoperative bleeding leading to discontinuation of ESD and a case of esophageal stricture due to extensive resection. During the follow-up period of a median for 42 months, a patient with local recurrence and another patient with liver metastasis were observed. One patient died of liver failure after receiving chemoradiotherapy as an additional treatment after ESD. No patient died of ESCC. CONCLUSION: This multicenter, retrospective cohort study demonstrated the safety and efficacy of ESD for ESCC with EVs. Further studies are needed to establish appropriate treatment methods for EVs before ESD and additional treatments for patients with insufficient ESD.
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Carcinoma de Células Escamosas , Ressecção Endoscópica de Mucosa , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Varizes Esofágicas e Gástricas , Humanos , Carcinoma de Células Escamosas/complicações , Carcinoma de Células Escamosas/cirurgia , Ressecção Endoscópica de Mucosa/efeitos adversos , Ressecção Endoscópica de Mucosa/métodos , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/cirurgia , Neoplasias Esofágicas/complicações , Neoplasias Esofágicas/cirurgia , Carcinoma de Células Escamosas do Esôfago/complicações , Carcinoma de Células Escamosas do Esôfago/cirurgia , Esofagoscopia/métodos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: The guidelines recommend additional gastrectomy after noncurative endoscopic resection for early gastric cancers (EGCs). However, no additional treatment might be acceptable in some patients aged ≥ 85 years. We aimed to identify this patient group using the data in a highly aged area. METHODS: We enrolled patients aged ≥ 85 years after noncurative endoscopic resection for EGCs at 30 institutions of the Tohoku district in Japan between 2002 and 2017. Treatment selection and prognosis after noncurative endoscopic resection were investigated. Fourteen candidates were evaluated using the Cox model to identify risk factors for poor overall survival (OS) in patients with no additional treatment. RESULTS: Of 1065 patients aged ≥ 85 years, 143 underwent noncurative endoscopic resection. Despite the guidelines' recommendation, 88.8% of them underwent no additional treatment. The 5-year OS rates in those with additional gastrectomy and those with no additional treatment were 63.1 and 65.2%, respectively. Multivariate analysis showed independent risk factors for poor OS in patients with no additional treatment were the high-risk category in the eCura system (hazard ratio [HR], 2.91), Charlson comorbidity index (CCI) ≥ 3 (HR, 2.78), and male (HR, 2.04). In patients with no additional treatment, nongastric cancer-specific survival was low (69.0% in 5 years), whereas disease-specific survival rates were very high in the low- and intermediate-risk categories of the eCura system (100.0 and 97.1%, respectively, in 5 years). CONCLUSIONS: No additional treatment may be acceptable in the low- and intermediate-risk categories of the eCura system in patients aged ≥ 85 years with noncurative endoscopic resection for EGCs.
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Ressecção Endoscópica de Mucosa , Neoplasias Gástricas , Humanos , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Neoplasias Gástricas/cirurgia , Japão/epidemiologia , Gastrectomia , Mucosa Gástrica/cirurgiaRESUMO
BACKGROUND: Although additional treatment is considered for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD), the actual benefits of this method remain to be elucidated. AIMS: We aimed to evaluate the prognostic benefits of additional treatment in such patients. METHODS: Between 2006 and 2017, we enrolled patients with pT1a-MM/pT1b-SM ESCC after ESD at 21 institutions in Japan. Overall survival (OS) and disease-specific survival (DSS) were compared between the additional treatment and follow-up groups after propensity score matching, to reduce the bias of baseline characteristics. A subgroup analysis was performed according to the pathological findings: category A, pT1a-MM but negative for lymphovascular invasion (LVI) and vertical margin (VM); category B, tumor invasion into the submucosa ≤ 200 µm but negative for LVI and VM; category C, others. RESULTS: Of 593 patients with pT1a-MM/pT1b-SM ESCC after ESD, 101 matched pairs were extracted after propensity score matching. The OSs were similar between the additional treatment and follow-up groups (80.6% vs. 78.6% in 5 years; P = 0.972). In a subgroup analysis, the OS in the additional treatment group was significantly lower than that in the follow-up group (65.7% vs. 95.2% in 5 years; P = 0.037) in category A, whereas OS did not significantly differ in category C (76.8% vs. 69.5% in 5 years; P = 0.360). CONCLUSIONS: Additional treatment after ESD in patients with pT1a-MM/pT1b-SM ESCC was not associated with an improved prognosis.
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Ressecção Endoscópica de Mucosa , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Carcinoma de Células Escamosas do Esôfago/cirurgia , Carcinoma de Células Escamosas do Esôfago/patologia , Prognóstico , Neoplasias Esofágicas/patologia , Ressecção Endoscópica de Mucosa/métodos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
PURPOSE: Little is known about the prognostic factors for survival after endoscopic submucosal dissection (ESD) in elderly patients with early gastric cancer (EGC). The aim of this study is to determine prognostic factors and a prediction model of 3-year survival after ESD for EGC in patients aged ≥ 85 years. METHODS: We retrospectively evaluated the clinical outcomes of 740 patients with EGC aged ≥ 85 years, who were treated by ESD at 30 institutions in Japan. Overall survival (OS) and disease-specific survival (DSS) were calculated with the Kaplan-Meier method. Prediction models for 3-year OS after ESD were estimated using the Cox proportional hazards model based on Uno's C-statistics. RESULTS: During the follow-up period, 309 patients died of any cause and 10 patients died of gastric cancer. OS and DSS after 3 years were 82.7% and 99.2%, respectively. No significant differences in OS were found among curability categories. The Cox proportional hazards model revealed the geriatric nutritional risk index (GNRI) and the Charlson comorbidity index (CCI) to be predictors of 3-year survival. We established a final model (EGC-2 model) expressed by GNRI - (2.2×CCI) with a cutoff value of 96. The overall survival rate was significantly lower in the model value < 96 group than in the model value ≥ 96 group (P < 0.001). CONCLUSIONS: The prediction model using GNRI and CCI will be useful to support decision-making for the treatment of EGC in elderly patients aged ≥ 85 years.
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Ressecção Endoscópica de Mucosa , Neoplasias Gástricas , Idoso , Humanos , Estudos Retrospectivos , Neoplasias Gástricas/cirurgia , Ressecção Endoscópica de Mucosa/métodos , Gastrectomia , Detecção Precoce de Câncer , Resultado do Tratamento , Mucosa GástricaRESUMO
OBJECTIVES: We aimed to clarify the prognostic factors for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD). METHODS: This retrospective study enrolled such patients at 21 institutions in Japan between 2006 and 2017. We evaluated 15 factors, including pathological risk categories for ESCC-specific mortality, six non-cancer-related indices, and treatment strategies. RESULTS: In the analysis of 593 patients, the 5-year overall and disease-specific survival rates were 83.0% and 97.6%, respectively. In a multivariate Cox analysis, male sex (hazard ratio [HR] 3.56), Charlson comorbidity index (CCI) ≥3 (HR 2.53), ages of 75-79 (HR 1.61) and ≥80 years (HR 2.04), prognostic nutrition index (PNI) <45 (HR 1.69), and pathological intermediate-risk (HR 1.63) and high-risk (HR 1.89) were prognostic factors. Subsequently, we developed a clinical risk classification for non-ESCC-related mortality based on the number of prognostic factors (age ≥75 years, male sex, CCI ≥3, PNI <45): low-risk, 0; intermediate-risk, 1-2; and high-risk, 3-4. The 5-year non-ESCC-related mortality rates for patients without additional treatment were 0.0%, 10.2%, and 45.8% in the low-, intermediate-, and high-risk groups, respectively. Meanwhile, the 5-year ESCC-specific mortality rates for the pathological low-, intermediate-, and high-risk groups were 0.3%, 5.3%, and 18.2%, respectively. CONCLUSIONS: We clarified prognostic factors for patients with pT1a-MM/pT1b-SM ESCC after ESD. The combined assessment of non-ESCC- and ESCC-related mortalities by the two risk classifications might help clinicians in deciding treatment strategies for such patients.
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Ressecção Endoscópica de Mucosa , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Masculino , Idoso de 80 Anos ou mais , Idoso , Carcinoma de Células Escamosas do Esôfago/patologia , Neoplasias Esofágicas/patologia , Estudos Retrospectivos , Prognóstico , Mucosa/cirurgia , Mucosa/patologia , Resultado do TratamentoRESUMO
BACKGROUND: We aimed to elucidate the risk of metastatic recurrence after endoscopic resection (ER) without additional treatment for esophageal squamous cell carcinomas (ESCCs) with tumor invasion into the muscularis mucosa (pT1a-MM) or submucosa (T1b-SM). METHODS: We retrospectively enrolled patients with pT1a-MM/pT1b-SM ESCC after ER at 21 institutions in Japan between 2006 and 2017. We compared metastatic recurrence between patients with and without additional treatment, stratified into category A (pT1a-MM with negative lymphovascular invasion [LVI] and vertical margin [VM]), B (tumor invasion into the submucosa ≤ 200 µm [pT1b-SM1] with negative LVI and VM), and C (others). Subsequently, using multivariate Cox analysis, we evaluated risk factors for metastatic recurrence after ER without additional treatment. RESULTS: We enrolled 593 patients, and metastatic recurrence occurred in 38 patients. Metastatic recurrence after additional treatment was significantly lower than that after no additional treatment in category C (9.1% vs. 23.6% in 5 years, p = 0.001), whereas no significant difference was noted in categories A (0.0% vs. 2.6%) and B (0.0% vs. 4.3%). In patients without additional treatment after ER, risk factors for metastatic recurrence were lymphatic invasion (hazard ratio [HR], 5.61), positive VM (HR, 4.55), and tumor invasion into the submucosa > 200 µm (HR, 3.25), and, but near half of the patients with metastatic recurrence had no further recurrence after salvage treatment, resulting in excellent 5-year disease-specific survival in categories A (99.6%) and B (100.0%). CONCLUSIONS: Closed follow-up with no additional treatment may be an acceptable option after ER in pT1a-MM/pT1b-SM1 ESCC with negative LVI and VM.
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Ressecção Endoscópica de Mucosa/métodos , Carcinoma de Células Escamosas do Esôfago/terapia , Mucosa/fisiopatologia , Idoso , Distribuição de Qui-Quadrado , Estudos de Coortes , Ressecção Endoscópica de Mucosa/estatística & dados numéricos , Carcinoma de Células Escamosas do Esôfago/epidemiologia , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Recidiva , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND/AIMS: For early gastric cancer (EGC) treated using endoscopic submucosal dissection (ESD) with poor curability defined by the Japanese Guidelines (non-curative EGC, N-EGC), additional gastrectomy has been recommended. However, N-EGC patients without additional gastrectomy often die of other diseases within a relatively short interval after ESD. It has been unclear whether additional gastrectomy is beneficial or not for such patients. The aim of this study was to clarify predictors for short-term survival of N-EGC patients without additional gastrectomy after ESD. METHODS: One hundred six N-EGC patients without additional gastrectomy were included in this study. Factors related to short-term survival, defined as death within 3 years after ESD, were evaluated using uni- and multivariate analyses by comparing patients with and without short-term survival (Groups S and C, respectively). RESULTS: During the mean follow-up period of 89 months, 39 patients died (14 patients died within 3 years, being Group S). The cause of death was gastric cancer for only 1 patient in the Group C. The 3- and 5-year overall survival rates were 86.8 and 81.8%, respectively, and the 3- and 5-years disease-specific survival rates were 100 and 98.9%, respectively. Univariate analyses showed that short-term survival was statistically associated with elevated morphology, high-risk status for lymph node metastases as defined by the eCura system, severe comorbidity (Charlson Comorbidity Index [CCI] ≥3), low level of activity in daily living (being unable to go out by oneself), habitation (a nursing home), and several poor nutritional prognostic indices (neutrophil to lymphocyte ratio ≥2.5, geriatric nutritional risk index <92, C-reactive protein ≥1.0). In the multivariate analysis, a high CCI (≥3) was the independent predictor for short-term survival after ESD (odds ratio, 8.1; 95% confidence interval, 1.53-43.0; p = 0.014). CONCLUSIONS: Severe comorbidity indicated by a high CCI score (≥3) was the independent predictor for short-term survival for EGC patients without additional gastrectomy after non-curative ESD. Since the cause of death for most patients was not gastric cancer, observational follow-ups without additional gastrectomy might be a reasonable option for patients with a poor general status indicated by a CCI ≥3.
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Ressecção Endoscópica de Mucosa , Neoplasias Gástricas , Idoso , Ressecção Endoscópica de Mucosa/efeitos adversos , Gastrectomia/efeitos adversos , Mucosa Gástrica/cirurgia , Humanos , Prognóstico , Estudos Retrospectivos , Neoplasias Gástricas/cirurgia , Taxa de Sobrevida , Resultado do TratamentoRESUMO
BACKGROUND/AIMS: The aim of this study was to evaluate the safety of sedation with propofol as an alternative to benzodiazepine drugs in outpatient endoscopy. METHODS: In this prospective study, examinees who underwent outpatient endoscopy under propofol sedation and submitted a nextday questionnaire with providing informed consent were evaluated. Periprocedural acute responses, late adverse events within 24 hours, and examinee satisfaction were evaluated. RESULTS: Among the 4,122 patients who received propofol in the 17,978 outpatient-based endoscopic examinations performed between November 2016 and March 2018, 2,305 eligible examinees (esophagogastroduodenoscopy for 1,340, endoscopic ultrasonography for 945, and total colonoscopy for 20) were enrolled, and their responses to a questionnaire were analyzed. The mean propofol dose was 69.6±24.4 mg (range, 20-200 mg). Diazepam, midazolam, and/or pentazocine in combination with propofol was administered to 146 examinees. Mild oxygen desaturation was observed in 59 examinees (2.6%); and mild bradycardia, in 2 (0.09%). Other severe reactions or late events did not occur. After eliminating 181 invalid responses, 97.7% (2,065/2,124) of the patients desired propofol sedation in future examinations. CONCLUSION: Propofol sedation was found to be safe-without severe adverse events or accidents-for outpatient endoscopy on the basis of the patients' next-day self-evaluation. Given the high satisfaction level, propofol sedation might be an ideal tool for painless endoscopic screening.
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A 15-mm whitish, depressed lesion was observed in the stomach of a 39-year-old using screening esophagogastroduodenoscopy. The lesion had grown to a size of 40mm and had a cobblestone-like appearance at an 11-year endoscopic follow-up. Using endoscopic submucosal dissection (ESD) as a diagnostic therapy, gastric mucosa-associated lymphoid tissue (MALT) lymphoma with MALT translocation gene 1 without Helicobacter pylori infection was detected. Although the patient did not undergo additional treatments, he remained alive without for recurrence 5 years after ESD.
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Ressecção Endoscópica de Mucosa , Infecções por Helicobacter , Helicobacter pylori , Linfoma de Zona Marginal Tipo Células B , Neoplasias Gástricas , Adulto , Mucosa Gástrica , Humanos , Tecido Linfoide , Masculino , Recidiva Local de NeoplasiaRESUMO
The ε subunit of Fo F1 -ATPase/synthase (Fo F1 ) plays a crucial role in regulating Fo F1 activity. To understand the physiological significance of the ε subunit-mediated regulation of Fo F1 in Bacillus subtilis, we constructed and characterized a mutant harboring a deletion in the C-terminal regulatory domain of the ε subunit (ε∆C ). Analyses using inverted membrane vesicles revealed that the ε∆C mutation decreased ATPase activity and the ATP-dependent H+ -pumping activity of Fo F1 . To enhance the effects of ε∆C mutation, this mutation was introduced into a ∆rrn8 strain harboring only two of the 10 rrn (rRNA) operons (∆rrn8 ε∆C mutant strain). Interestingly, growth of the ∆rrn8 ε∆C mutant stalled at late-exponential phase. During the stalled growth phase, the membrane potential of the ∆rrn8 ε∆C mutant cells was significantly reduced, which led to a decrease in the cellular level of 70S ribosomes. The growth stalling was suppressed by adding glucose into the culture medium. Our findings suggest that the C-terminal region of the ε subunit is important for alleviating the temporal reduction in the membrane potential, by enhancing the ATP-dependent H+ -pumping activity of Fo F1 .
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Bacillus subtilis/enzimologia , Bacillus subtilis/metabolismo , Membrana Celular/fisiologia , Potenciais da Membrana , Subunidades Proteicas/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Prótons , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Domínios Proteicos , Subunidades Proteicas/genética , ATPases Translocadoras de Prótons/genética , Deleção de SequênciaRESUMO
Afferent loop syndrome is often difficult to resolve. Among patients with afferent loop syndrome whose data were extracted from databases, 5 patients in whom metal stent placement was attempted were included and evaluated in this study. The procedure was technically successful without any adverse events in all patients. Metal stent(s) was placed with an endoscope in the through-the-scope manner in 4 patients and via a percutaneous route in 1 patient. Obvious clinical efficacy was observed in all patients. Adverse events related to the procedure and stent occlusion during the follow-up period were not observed. Metal stent placement for malignant obstruction of the afferent loop was found to be safe and feasible.
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YbaO is an uncharacterized AsnC-family transcription factor of Escherichia coli. In both Salmonella enterica and Pantoea ananatis, YbaO homologues were identified to regulate the adjacent gene encoding cysteine desulfhydrase for detoxification of cysteine. Using the genomic SELEX (systematic evolution of ligands by exponential enrichment) screening system, we identified the yhaOM operon, located far from the ybaO gene on the E. coli genome, as a single regulatory target of YbaO. In both gel shift assay in vitro and reporter and Northern blot assays in vivo, YbaO was found to regulate the yhaOM promoter. The growth of mutants lacking either ybaO or its targets yhaOM was delayed in the presence of cysteine, indicating involvement of these genes in cysteine detoxification. In the major pathway of cysteine degradation, hydrogen sulfide is produced in wild-type E. coli, but its production was not observed in each of the ybaO, yhaO and yhaM mutants. The yhaOM promoter was activated in the presence of cysteine, implying the role of cysteine in activation of YbaO. Taken together, we propose that YbaO is the cysteine-sensing transcriptional activator of the yhaOM operon, which is involved in the detoxification of cysteine. We then propose the naming of ybaO as decR (regulator of detoxification of cysteine).
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Cisteína/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Fatores de Transcrição/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Óperon , Regiões Promotoras Genéticas , Fatores de Transcrição/genéticaRESUMO
CRP (cAMP receptor protein), the global regulator of genes for carbon source utilization in the absence of glucose, is the best-studied prokaryotic transcription factor. A total of 195 target promoters on the Escherichia coli genome have been proposed to be under the control of cAMP-bound CRP. Using the newly developed Genomic SELEX screening system of transcription factor-binding sequences, however, we have identified a total of at least 254 CRP-binding sites. Based on their location on the E. coli genome, we predict a total of at least 183 novel regulation target operons, altogether with the 195 hitherto known targets, reaching to the minimum of 378 promoters as the regulation targets of cAMP-CRP. All the promoters selected from the newly identified targets and examined by using the lacZ reporter assay were found to be under the control of CRP, indicating that the Genomic SELEX screening allowed to identify the CRP targets with high accuracy. Based on the functions of novel target genes, we conclude that CRP plays a key regulatory role in the whole processes from the selective transport of carbon sources, the glycolysis-gluconeogenesis switching to the metabolisms downstream of glycolysis, including tricarboxylic acid (TCA) cycle, pyruvate dehydrogenase (PDH) pathway and aerobic respiration. One unique regulation mode is that a single and the same CRP molecule bound within intergenic regions often regulates both of divergently transcribed operons.
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Carbono/metabolismo , Proteína Receptora de AMP Cíclico/metabolismo , Proteínas de Escherichia coli/metabolismo , Sequência de Bases , Sítios de Ligação , Transporte Biológico , Sequência Consenso , AMP Cíclico/metabolismo , Proteína Receptora de AMP Cíclico/química , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Genômica , Análise de Sequência com Séries de Oligonucleotídeos , Transcrição GênicaRESUMO
The rpoZ gene for the omega subunit of Escherichia coli RNA polymerase constitutes single operon with the spoT gene, which is responsible for the maintenance of stringent response under nutrient starvation conditions. To identify the physiological role of the omega subunit, we compared the gene expression profile of wild-type Escherichia coli with that of an rpoZ deleted strain by microarray analysis using an E. coli DNA chip. Here we report on a set of genes which show changes in expression profile following the removal of rpoZ. We have seen that relA, which is responsible for the synthesis of the stringent factor ppGpp and many ribosomal proteins, exhibited noticeable changes in mRNA levels and were therefore further analyzed for their expression using a GFP/RFP two-fluorescent protein promoter assay vector. In the absence of rpoZ, the promoter for the relA gene was severely impaired, but the promoters from the ribosomal protein genes were not affected as much. Taking these results together we propose that the omega subunit is involved in regulation of the relA gene, but induction of the stringently controlled genes in the absence of rpoZ is, at least in part, attributable to a decrease in ppGpp level.