Endoscopic intervention as a decisive tool in the prognosis of cancer patients.

Cyanacrylate is not free of complications and a more commonly used alternative in clinical practice are prostheses that have the disadvantage of migrating in these cases where there is no stenosis; however, with their fixation using a specific device, migrations are greatly reduced. A good alternative to cyanacrylate, especially in cases of orifices or large tracts in which complications may appear, are the prostheses, which are also easier to handle in clinical practice. Sometimes cancer patients have upper gastrointestinal complications no subsidiary to surgical treatment, like a tumor fistula, that contraindicate chemotherapy. In situations like this, endoscopic intervention can be a potentially profitable alternative that impacts the patient's prognosis.

Upper digestive bleeding secondary to duodenal infiltration due to pancreatic cancer: a therapeutic challenge.

A 68-year-old woman with stage IV pancreatic adenocarcinoma (liver and lymph node metastases) on first-line treatment with gemcitabine. As a non-oncological comorbidity, the patient was anticoagulated with enoxaparin 8000 IU/24 hours because she had a mitral valve prosthesis. The patient made a medical consultation for presenting vomits which looked like coffee grounds and melaena. In the complete blood count, a hemoglobin of 7.5 g/dL was detected. Transfusion support, pantoprazole infusion (80 mg in 500 cc of 0.9% SSF every 12 hours) and parenteral nutrition were prescribed. Tranexamic was not prescribed due to the patient's cardiological history.

Heavy metal pollution index calculation in geochemistry assessment: a case study on Playa Las Petroleras.

This work is aimed to assess potential risk associated with the presence of metals and metalloids in soil at "Playa Las Petroleras" sector, located in Antofagasta (Chile). The zone under study has been affected by four oil spill events. This sector is located in an urban area by the sea. So, it has a great social and environmental relevance. The concentrations of 15 elements in soil samples were assessed, four of them presenting potential ecological risk: As, Co, Cu, and Pb. Nine pollution indices were applied to data: four single pollution indices and five integrated pollution indices to assess soil pollution. The single pollution indices show that the site bears potential ecological and environmental risk due to the presence of Cu, the site being classified as highly contaminated owing to a severe enrichment of this metal. For Co, all the indices allow classifying the site as little or uncontaminated, while the level of As and Pb pollution could be considered as ranging from uncontaminated to moderately contaminated. The integrated pollution indices show that average concentrations are highly contaminated mainly owing to the presence of Cu.

External Validity of Somatostatin Analogs Trials in Advanced Neuroendocrine Neoplasms: The GETNE-TRASGU Study.

INTRODUCTION: Somatostatin analogs (SSA) prolong progression-free survival (PFS) in patients with well-differentiated gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). However, the eligibility criteria in randomized clinical trials (RCTs) have been restricted, which contrasts with the vast heterogeneity found in NENs. METHODS: We identified patients with well-differentiated (Ki-67% ≤20%), metastatic GEP-NENs treated in first line with SSA monotherapy from the Spanish R-GETNE registry. The therapeutic effect was evaluated using a Bayesian Cox model. The objective was to compare survival-based outcomes from real-world clinical practice versus RCTs. RESULTS: The dataset contained 535 patients with a median age of 62 years (range: 26-89). The median Ki-67% was 4 (range: 0-20). The most common primary tumor sites were as follows: midgut, 46%; pancreas, 34%; unknown primary, 10%; and colorectal, 10%. Half of the patients received octreotide LAR (n = 266) and half, lanreotide autogel (n = 269). The median PFS was 28.0 months (95% CI: 22.1-32.0) for octreotide versus 30.1 months (95% CI: 23.1-38.0) for lanreotide. The overall hazard ratio for lanreotide versus octreotide was 0.90 (95% credible interval: 0.71-1.12). The probability of effect sizes >30% with lanreotide versus octreotide was 2 and 6% for midgut and foregut NENs, respectively. CONCLUSION: Our study evaluated the external validity of RCTs examining SSAs in the real world, as well as the main effect-modifying factors (progression status, symptoms, tumor site, specific metastases, and analytical data). Our results indicate that both octreotide LAR and lanreotide autogel had a similar effect on PFS. Consequently, both represent valid alternatives in patients with well-differentiated, metastatic GEP-NENs.

Immune-mediated colitis secondary to treatment with nivolumab-ipilimumab in a patient with stage IV kidney cancer: what do we do when corticosteroids fail?

52-year-old male. The patient had a stage IV renal carcinoma with bone metastases. He started first-line treatment with nivolumab (3 mg/kg) associated with ipilimumab (1 mg/kg). After two cycles of treatment, the patient reported hemorrhagic diarrhoea (7 to 10 stools daily), with visceral nociceptive abdominal pain of moderate intensity and oral intolerance.

External validity of docetaxel triplet trials in advanced gastric cancer: are there patients who still benefit?

BACKGROUND: The purpose of our study was to develop an online calculator to estimate the effect of docetaxel triplets (DPF) in first line of advanced gastric cancer (AGC), and to assess the external validity of docetaxel trials in individual patients. METHODS: The study includes patients with HER2(-) AGC treated with platin and fluoropyrimidine (PF) or with DPF in first line. Treatment effect and interactions were assessed using Bayesian accelerated failure time models. RESULT: The series comprises 1376 patients; 238 treated with DPF and 1138 with PF between 2008 and 2019. DPF was associated with increased progression-free survival (PFS) and overall survival (OS) with time ratio (TR) 1.27 (95% credible interval [CrI], 1.15-1.40), and TR 1.19 (95% CrI, 1.09-1.27), respectively. Serious adverse events were more common with DPF, particularly hematological effects (32% vs 22%). Younger participants received greater DPF dose density without achieving greater disease control, while severe toxicity was likewise higher. DPF yielded superior OS in Lauren intestinal (TR 1.27, 95% CrI, 1.08-1.11) vs diffuse subtype (TR 1.17, 95% CrI, 1.09-1.24) and the probability of increasing OS > 15% was 90% vs 67% in each subtype, respectively. The effect dwindles over time, which can be attributed to pathological changes and clinical practice changes. CONCLUSION: Our study confirms the effect of DPF is highly dependent on several clinical-pathological variables, with discreet and gradually declining benefit over platinum doublets in later years, at the expense of increased toxicity. These results may help to underpin the idea that external validity of AGC trials should be revised regularly.

Is advanced esophageal adenocarcinoma a distinct entity from intestinal subtype gastric cancer? Data from the AGAMENON-SEOM Registry.

BACKGROUND: Advanced esophageal adenocarcinoma (EAC) is generally treated similarly to advanced gastroesophageal junction (GEJ-AC) and gastric (GAC) adenocarcinomas, although GAC clinical trials rarely include EAC. This work sought to compare clinical characteristics and treatment outcomes of advanced EAC with those of GEJ-AC and GAC and examine prognostic factors. PATIENTS AND METHODS: Participants comprised patients with advanced EAC, intestinal GEJ-AC, and GAC treated with platin and fluoropyrimidine (plus trastuzumab when HER2 status was positive). Overall and progression-free survival were estimated using the Kaplan-Meier method. Cox proportional hazards regression gauged the prognostic value of the AGAMENON model. RESULTS: Between 2008 and 2019, 971 participants from the AGAMENON-SEOM registry were recruited at 35 centers. The sample included 67.3% GAC, 13.3% GEJ-AC, and 19.4% EAC. Pulmonary metastases were most common in EAC and peritoneal metastases in GAC. Median PFS and OS were 7.7 (95% CI 7.3-8.0) and 13.9 months (12.9-14.7). There was no difference in PFS or OS between HER2- and HER2+ tumors from the three locations (p > 0.05). Five covariates were found to be prognostic for the entire sample: ECOG-PS, histological grade, number of metastatic sites, NLR, and HER2+ tumors treated with trastuzumab. In EAC, the same variables were prognostic except for grade. The favorable prognosis for HER2+ cancers treated with trastuzumab was homogenous for all three subgroups (p = 0.351) and, after adjusting for the remaining covariates, no evidence supported primary tumor localization as a prognostic factor (p = 0.331). CONCLUSION: Our study supports the hypothesis that EAC exhibits clinicopathological characteristics, prognostic factors, and treatment outcomes comparable to intestinal GEJ-AC and GAC.

Hydrochemical evolution of the Reocín mine filling water (Spain).

The Reocín mine is located in Cantabrian region, in northern Spain. Its exploitation ended in 2003 due to the exhaustion of its reserves. In November 2004, the controlled flooding of the openpit began. During this process, both the qualities of stored water and piezometric levels have been monitored to control the possible water detraction from the Saja-Besaya hydrographic system. This paper deals with the water chemistry analysis of the pit lake surface, as well as the different conditions of the area. Geological and hydrogeological contexts play an important role in the lake water chemistry. The lake water quality continues improving. The sulphate content and zinc concentrations are already below the permitted pouring limits. Three factors are distinguished: the washing of the mine shafts is completed; the water supply from the aquifer contributes to the dissolution of the salt content and the bedrock, and dolomite, which neutralizes acid waters and improves the water quality during the flooding process with a pH value of 8. Owing to these conditions, the stored water meets the necessary conditions for discharge and provides the opportunities to use it.

SEVERE GASTROINTESTINAL TOXICITY SECONDARY TO FLUOROPYRIMIDINES: ACUTE ESOPHAGEAL NECROSIS ASSOCIATED EXTENSIVE DUODENAL MUCOSITIS.

A 68-year-old male with stage IV sigmoid adenocarcinoma (liver metastases). KRAS and BRAF wild type. No other medical-surgical history of interest. In first line treatment with 5-Fluoracil, oxaliplatin and cetuximab. One week after the administration of the third cycle of therapy, the patient presented vomits which looked like coffee grounds. Gastroscopy showed an esophagus with ulcers, in its proximal third, which converged distally, appearing a black esophagus (Image 1), while gastric cavity had not relevant alterations. On duodenal bulb there were abundant ulcerations in different stages, radially distributed, without active bleeding or visible vessel, suggesting extensive mucositis (Image 2). Acute esophageal necrosis (AEN) is defined endoscopically by a circumferential black-appearing esophageal mucosa with nearly universal involvement of the distal esophagus and abrupt transition at the gastroesophageal junction, with variable proximal extension (1). The 10% of patients with AEN have a history of malignancy (2). Cancer is associated with cachexia and immune dysregulation, thereby decreasing mucosal regenerative ability and increasing susceptibility. AEN often follows chemotherapy administration (1). Mucositis, stomatitis, or esophagopharyngitis (which may lead to mucosal sloughing or ulceration) may occur with fluorouracil (3). In this patient, severity of the adverse event forced the withhold of this drug.

An acetylatable lysine controls CRP function in E. coli.

Transcriptional regulation is the key to ensuring that proteins are expressed at the proper time and the proper amount. In Escherichia coli, the transcription factor cAMP receptor protein (CRP) is responsible for much of this regulation. Questions remain, however, regarding the regulation of CRP activity itself. Here, we demonstrate that a lysine (K100) on the surface of CRP has a dual function: to promote CRP activity at Class II promoters, and to ensure proper CRP steady state levels. Both functions require the lysine's positive charge; intriguingly, the positive charge of K100 can be neutralized by acetylation using the central metabolite acetyl phosphate as the acetyl donor. We propose that CRP K100 acetylation could be a mechanism by which the cell downwardly tunes CRP-dependent Class II promoter activity, whilst elevating CRP steady state levels, thus indirectly increasing Class I promoter activity. This mechanism would operate under conditions that favor acetate fermentation, such as during growth on glucose as the sole carbon source or when carbon flux exceeds the capacity of the central metabolic pathways.

Evaluating radiological response in pancreatic neuroendocrine tumours treated with sunitinib: comparison of Choi versus RECIST criteria (CRIPNET_ GETNE1504 study).

BACKGROUND: The purpose of our study was to analyse the usefulness of Choi criteria versus RECIST in patients with pancreatic neuroendocrine tumours (PanNETs) treated with sunitinib. METHOD: A multicentre, prospective study was conducted in 10 Spanish centres. Computed tomographies, at least every 6 months, were centrally evaluated until tumour progression. RESULTS: One hundred and seven patients were included. Median progression-free survival (PFS) by RECIST and Choi were 11.42 (95% confidence interval [CI], 9.7-15.9) and 15.8 months (95% CI, 13.9-25.7). PFS by Choi (Kendall's τ = 0.72) exhibited greater correlation with overall survival (OS) than PFS by RECIST (Kendall's τ = 0.43). RECIST incorrectly estimated prognosis in 49.6%. Partial response rate increased from 12.8% to 47.4% with Choi criteria. Twenty-four percent of patients with progressive disease according to Choi had stable disease as per RECIST, overestimating treatment effect. Choi criteria predicted PFS/OS. Changes in attenuation occurred early and accounted for 21% of the variations in tumour volume. Attenuation and tumour growth rate (TGR) were associated with improved survival. CONCLUSION: Choi criteria were able to capture sunitinib's activity in a clinically significant manner better than RECIST; their implementation in standard clinical practice shall be strongly considered in PanNET patients treated with this drug.

Prognostic Nomogram and Patterns of Use of FOLFIRI-Aflibercept in Advanced Colorectal Cancer: A Real-World Data Analysis.

INTRODUCTION: The VELOUR study evaluated the efficacy and safety of adding aflibercept to FOLFIRI (fluorouracil, leucovorin, irinotecan) in second-line therapy for metastatic colorectal cancer (mCRC). However, a nomogram that can stratify patients according to prognosis is unavailable, and the frequency and effect of the pragmatic use of modified schedules in actual practice remains unknown. METHOD: The sample consists of 250 patients with mCRC treated with aflibercept and irinotecan-based chemotherapy at nine Spanish academic centers between January 2013 and September 2015. The result of a Cox proportional hazards model regression for overall survival (OS), adjusted for covariates available in daily practice, was represented as a nomogram and web-based calculator. Harrell's c-index was used to assess discrimination. RESULTS: The prognostic nomogram for OS includes six variables: Eastern Cooperative Oncology Group performance status, tumor location, number of metastatic sites, mutational status, better response to previous treatment(s), and carcinoembryonic antigen. The model is well calibrated and has acceptable discriminatory capacity (optimism-corrected c-index, 0.723; 95% confidence interval [CI], 0.666-0.778). Median OS was 6.1 months (95% CI, 5.1-8.8), 12.4 months (95% CI, 9.36-14.8), and 22.9 months (95% CI, 16.6-not reached) for high-, intermediate-, and low-risk groups, respectively. Age, comorbidity, or use of modified FOLFIRI regimens did not affect prognosis in this series. Grade 3-4 adverse events were less common following modified schedules. The admission rate because of toxicity was higher in ≥65 years (9.7% vs. 19.6%; odds ratio, 2.26; p = .029). CONCLUSION: We have developed and internally validated a prognostic model for use in individuals with colorectal cancer initiating therapy with FOLFIRI-aflibercept to predict both OS and the effect of pragmatic modifications of the classic regime on efficacy and safety. This can aid in decision making and in designing future trials. IMPLICATIONS FOR PRACTICE: In this study, the authors developed and conducted the internal validation of a prognostic nomogram that makes it possible to stratify patients who are eligible for second-line FOLFIRI-aflibercept based on their probability of survival. This model was developed in a multicenter sample from nine Spanish hospitals. Furthermore, to increase the study's validity, the practical use of aflibercept in this setting was investigated, including doses or pragmatic modifications. The results suggest that the modified schedules often used in this daily clinical practice-based patient population are associated with less severe toxicity without apparent detriment to survival endpoints. It is believed that these data complement the information provided by the VELOUR trial and are relevant for the oncologist in treating colon cancer in the second-line setting.

Fructose metabolism in Chromohalobacter salexigens: interplay between the Embden-Meyerhof-Parnas and Entner-Doudoroff pathways.

BACKGROUND: The halophilic bacterium Chromohalobacter salexigens metabolizes glucose exclusively through the Entner-Doudoroff (ED) pathway, an adaptation which results in inefficient growth, with significant carbon overflow, especially at low salinity. Preliminary analysis of C. salexigens genome suggests that fructose metabolism could proceed through the Entner-Doudoroff and Embden-Meyerhof-Parnas (EMP) pathways. In order to thrive at high salinity, this bacterium relies on the biosynthesis and accumulation of ectoines as major compatible solutes. This metabolic pathway imposes a high metabolic burden due to the consumption of a relevant proportion of cellular resources, including both energy molecules (NADPH and ATP) and carbon building blocks. Therefore, the existence of more than one glycolytic pathway with different stoichiometries may be an advantage for C. salexigens. The aim of this work is to experimentally characterize the metabolism of fructose in C. salexigens. RESULTS: Fructose metabolism was analyzed using in silico genome analysis, RT-PCR, isotopic labeling, and genetic approaches. During growth on fructose as the sole carbon source, carbon overflow was not observed in a wide range of salt concentrations, and higher biomass yields were reached. We unveiled the initial steps of the two pathways for fructose incorporation and their links to central metabolism. While glucose is metabolized exclusively through the Entner-Doudoroff (ED) pathway, fructose is also partially metabolized by the Embden-Meyerhof-Parnas (EMP) route. Tracking isotopic label from [1-13C] fructose to ectoines revealed that 81% and 19% of the fructose were metabolized through ED and EMP-like routes, respectively. Activities of enzymes from both routes were demonstrated in vitro by 31P-NMR. Genes encoding predicted fructokinase and 1-phosphofructokinase were cloned and the activities of their protein products were confirmed. Importantly, the protein encoded by csal1534 gene functions as fructose bisphosphatase, although it had been annotated previously as pyrophosphate-dependent phosphofructokinase. The gluconeogenic rather than glycolytic role of this enzyme in vivo is in agreement with the lack of 6-phosphofructokinase activity previously described. CONCLUSIONS: Overall, this study shows that C. salexigens possesses a greater metabolic flexibility for fructose catabolism, the ED and EMP pathways contributing to a fine balancing of energy and biosynthetic demands and, subsequently, to a more efficient metabolism.

Prognostic factors for survival with nab-paclitaxel plus gemcitabine in metastatic pancreatic cancer in real-life practice: the ANICE-PaC study.

BACKGROUND: Treatment with nab-paclitaxel plus gemcitabine increases survival in patients with metastatic pancreatic cancer. However, the assessment of treatment efficacy and safety in non-selected patients in a real-life setting may provide useful information to support decision-making processes in routine practice. METHODS: Retrospective, multicenter study including patients with metastatic pancreatic cancer, who started first-line treatment with nab-paclitaxel plus gemcitabine between December 2013 and June 2015 according to routine clinical practice. In addition to describing the treatment pattern, overall survival (OS) and progression-free survival (PFS) were assessed for the total sample and the exploratory subgroups based on the treatment and patients' clinical characteristics. RESULTS: All 210 eligible patients had a median age of 65.0 years (range 37-81). Metastatic pancreatic adenocarcinoma was recurrent in 46 (21.9%) patients and de novo in 164 (78.1%); 38 (18%) patients had a biliary stent. At baseline, 33 (18.1%) patients had an ECOG performance status ≥2. Patients received a median of four cycles of treatment (range 1-21), with a median duration of 3.5 months; 137 (65.2%) patients had a dose reduction of nab-paclitaxel and/or gemcitabine during treatment, and 33 (17.2%) discontinued treatment due to toxicity. Relative dose intensity (RDI) for nab-paclitaxel, gemcitabine, and the combined treatment was 66.7%. Median OS was 7.2 months (95% CI 6.0-8.5), and median PFS was 5.0 months (95% CI 4.3-5.9); 50 patients achieved either a partial or complete response (ORR 24.6%). OS was influenced by baseline ECOG PS, NLR and CA 19.9, but not by age ≥ 70 years and/or the presence of hepatobiliary stent or RDI < 85%. All included variables, computed as dichotomous, showed a significant contribution to the Cox regression model to build a nomogram for predicting survival in these patients: baseline ECOG 0-1 vs. 2-3 (p = 0.030), baseline NLR > 3 vs. ≤ 3 (p = 0.043), and baseline CA 19.9 > 37 U/mL vs. ≤37 U/mL (p = 0.004). CONCLUSIONS: Nab-Paclitaxel plus gemcitabine remain effective in a real-life setting, despite the high burden of dose reductions and poorer performance of these patients. A nomogram to predict survival using baseline ECOG performance status, NLR and CA 19.9 is proposed.

Insights into metabolic osmoadaptation of the ectoines-producer bacterium Chromohalobacter salexigens through a high-quality genome scale metabolic model.

BACKGROUND: The halophilic bacterium Chromohalobacter salexigens is a natural producer of ectoines, compatible solutes with current and potential biotechnological applications. As production of ectoines is an osmoregulated process that draws away TCA intermediates, bacterial metabolism needs to be adapted to cope with salinity changes. To explore and use C. salexigens as cell factory for ectoine(s) production, a comprehensive knowledge at the systems level of its metabolism is essential. For this purpose, the construction of a robust and high-quality genome-based metabolic model of C. salexigens was approached. RESULTS: We generated and validated a high quality genome-based C. salexigens metabolic model (iFP764). This comprised an exhaustive reconstruction process based on experimental information, analysis of genome sequence, manual re-annotation of metabolic genes, and in-depth refinement. The model included three compartments (periplasmic, cytoplasmic and external medium), and two salinity-specific biomass compositions, partially based on experimental results from C. salexigens. Using previous metabolic data as constraints, the metabolic model allowed us to simulate and analyse the metabolic osmoadaptation of C. salexigens under conditions for low and high production of ectoines. The iFP764 model was able to reproduce the major metabolic features of C. salexigens. Flux Balance Analysis (FBA) and Monte Carlo Random sampling analysis showed salinity-specific essential metabolic genes and different distribution of fluxes and variation in the patterns of correlation of reaction sets belonging to central C and N metabolism, in response to salinity. Some of them were related to bioenergetics or production of reducing equivalents, and probably related to demand for ectoines. Ectoines metabolic reactions were distributed according to its correlation in four modules. Interestingly, the four modules were independent both at low and high salinity conditions, as they did not correlate to each other, and they were not correlated with other subsystems. CONCLUSIONS: Our validated model is one of the most complete curated networks of halophilic bacteria. It is a powerful tool to simulate and explore C. salexigens metabolism at low and high salinity conditions, driving to low and high production of ectoines. In addition, it can be useful to optimize the metabolism of other halophilic bacteria for metabolite production.

Lauren subtypes of advanced gastric cancer influence survival and response to chemotherapy: real-world data from the AGAMENON National Cancer Registry.

BACKGROUND: The choice of chemotherapy in HER2-negative gastric cancer is based on centre's preferences and adverse effects profile. No schedule is currently accepted as standard, nor are there any factors to predict response, other than HER2 status. We seek to evaluate whether Lauren type influences the efficacy of various chemotherapies and on patient overall survival (OS). METHODS: We have conducted a multicenter study in 31 hospitals. The eligibility criteria include diagnosis of stomach or gastroesophageal junction adenocarcinoma, HER2 negativity, and chemotherapy containing 2-3 drugs. Cox proportional hazards regression adjusted for confounding factors, with tests of 'treatment-by-histology' interaction, was used to estimate treatment effect. RESULTS: Our registry contains 1303 tumours analysable for OS end points and 730 evaluable for overall response rate (ORR). A decrease in ORR was detected in the presence of a diffuse component: odds ratio 0.719 (95% confidence interval (CI), 0.525-0.987), P=0.039. Anthracycline- or docetaxel-containing schedules increased ORR only in the intestinal type. The diffuse type displayed increased mortality with hazard ratio (HR) of 1.201 (95% CI, 1.054-1.368), P=0.0056. Patients receiving chemotherapy with docetaxel exhibited increased OS limited to the intestinal type: HR 0.65 (95% CI, 0.49-0.87), P=0.024, with no increment in OS for the subset having a diffuse component. With respect to progression-free survival (PFS), a significant interaction was seen in the effect of docetaxel-containing schedules, with better PFS limited to the intestinal type subgroup, in the comparison against any other schedule: HR 0.65 (95% CI, 0.50-0.85), P=0.015, and against anthracycline-based regimens: HR 0.64 (95% CI, 0.46-0.88), P=0.046. CONCLUSIONS: As a conclusion, in this registry, Lauren classification tumour subtypes predicted survival and responded differently to chemotherapy. Future clinical trials should stratify effect estimations based on histology.

Understanding the interplay of carbon and nitrogen supply for ectoines production and metabolic overflow in high density cultures of Chromohalobacter salexigens.

BACKGROUND: The halophilic bacterium Chromohalobacter salexigens has been proposed as promising cell factory for the production of the compatible solutes ectoine and hydroxyectoine. This bacterium has evolved metabolic adaptations to efficiently grow under high salt concentrations by accumulating ectoines as compatible solutes. However, metabolic overflow, which is a major drawback for the efficient conversion of biological feedstocks, occurs as a result of metabolic unbalances during growth and ectoines production. Optimal production of ectoines is conditioned by the interplay of carbon and nitrogen metabolisms. In this work, we set out to determine how nitrogen supply affects the production of ectoines. RESULTS: Chromohalobacter salexigens was challenged to grow in media with unbalanced carbon/nitrogen ratio. In C. salexigens, overflow metabolism and ectoines production are a function of medium composition. At low ammonium conditions, the growth rate decreased importantly, up to 80%. Shifts in overflow metabolism were observed when changing the C/N ratio in the culture medium. 13C-NMR analysis of ectoines labelling revealed a high metabolic rigidity, with almost constant flux ratios in all conditions assayed. Unbalanced C/N ratio led to pyruvate accumulation, especially upon N-limitation. Analysis of an ect - mutant demonstrated the link between metabolic overflow and ectoine biosynthesis. Under non ectoine synthesizing conditions, glucose uptake and metabolic overflow decreased importantly. Finally, in fed-batch cultures, biomass yield was affected by the feeding scheme chosen. High growth (up to 42.4 g L-1) and volumetric ectoine yields (up to 4.21 g L-1) were obtained by minimizing metabolite overflow and nutrient accumulation in high density cultures in a low nitrogen fed-batch culture. Moreover, the yield coefficient calculated for the transformation of glucose into biomass was 30% higher in fed-batch than in the batch culture, demonstrating that the metabolic efficiency of C. salexigens can be improved by careful design of culture feeding schemes. CONCLUSIONS: Metabolic shifts observed at low ammonium concentrations were explained by a shift in the energy required for nitrogen assimilation. Carbon-limited fed-batch cultures with reduced ammonium supply were the best conditions for cultivation of C. salexigens, supporting high density growth and maintaining high ectoines production.

Collateral sensitivity to cold stress and differential BCL-2 family expression in new daunomycin-resistant lymphoblastoid cell lines.

The acquisition of a multidrug-resistant (MDR) phenotype by tumor cells is one of the main causes of chemotherapy failure in cancer, and, usually, is due to the increased expression of P-glycoprotein (MDR-1, P-gp, ABCB1), a pump that expels chemotherapeutics from the cell and/or regulates apoptosis. Thus, it is fundamental to find drugs or stress stimuli with a capacity to induce apoptosis in such cells and to identify the mechanisms involved. We address this matter in human cells and establish new daunomycin (DNM)-resistant cell lines (IM-9R) by exposing the parental lymphoblastic cells (IM-9) to increasing doses of the anti-neoplastic drug, daunomycin. The resistance level of IM-9R cell lines, MDR-1 expression and functionality, collateral sensitivity and Bcl-2 and caspases protein expression are analyzed. As a result, we show for the first time that, unlike the parental cells, human lymphoblastic resistant cells exhibit collateral sensitivity to cold stress, confirming that this phenomenon is not exclusive to murine leukemic cells, but a broader one associated with the acquisition of drug resistance. Furthermore, the new resistant cell lines undergo a significant increase in active caspase-3 and -9 levels and drastic changes in Bcl-2 family protein expression during the process of MDR phenotype acquisition.

Acetate metabolism regulation in Escherichia coli: carbon overflow, pathogenicity, and beyond.

Acetate is ubiquitously found in natural environments. Its availability in the gut is high as a result of the fermentation of nutrients, and although it is rapidly absorbed by intestinal mucosa, it can also be used as carbon source by some members of gut microbiota. The metabolism of acetate in Escherichia coli has attracted the attention of the scientific community due to its role in central metabolism and its link to multiple physiological features. In this microorganism, acetate is involved directly or indirectly on the regulation of functional processes, such as motility, formation of biofilms, and responses to stress. Furthermore, it is a relevant nutrient in gut, where it serves additional roles, which regulate or, at least, modulate pathophysiological responses of E. coli and other bacteria. Acetate is one of the major by-products of anaerobic (fermenting) metabolism, and it is also produced under fully aerobic conditions. This acetate overflow is recognized as one of the major drawbacks limiting E. coli's productivity in biotechnological processes. This review sums up current knowledge on acetate metabolism in E. coli, explaining the major milestones that have led to deciphering its complex regulation in the K-12 strain. Major differences in the metabolism of acetate in other strains will be underlined, with a focus on strains of biotechnological and biomedical interest.

Protein acetylation affects acetate metabolism, motility and acid stress response in Escherichia coli.

Although protein acetylation is widely observed, it has been associated with few specific regulatory functions making it poorly understood. To interrogate its functionality, we analyzed the acetylome in Escherichia coli knockout mutants of cobB, the only known sirtuin-like deacetylase, and patZ, the best-known protein acetyltransferase. For four growth conditions, more than 2,000 unique acetylated peptides, belonging to 809 proteins, were identified and differentially quantified. Nearly 65% of these proteins are related to metabolism. The global activity of CobB contributes to the deacetylation of a large number of substrates and has a major impact on physiology. Apart from the regulation of acetyl-CoA synthetase, we found that CobB-controlled acetylation of isocitrate lyase contributes to the fine-tuning of the glyoxylate shunt. Acetylation of the transcription factor RcsB prevents DNA binding, activating flagella biosynthesis and motility, and increases acid stress susceptibility. Surprisingly, deletion of patZ increased acetylation in acetate cultures, which suggests that it regulates the levels of acetylating agents. The results presented offer new insights into functional roles of protein acetylation in metabolic fitness and global cell regulation.