RESUMEN
In this study, real marine sediments polluted by petroleum compounds were treated by means of a bioslurry pilot scale reactor. The treatment performance was evaluated by measuring the removal of total petroleum hydrocarbon (TPH), coupled to further analyses required to understand the mechanisms involved in the biodegradation process. The maximum TPH-removal efficiency reached 86â¯% at the end of experiments. Moreover, high throughput 16S RNA gene sequencing was used to describe the microbiome composition in sediment prior to, and after, bioslurry treatment, in order to identify the taxa mostly entailed in the TPH removal process. The raw sediment was mostly colonized by members of Sulfurimonas genus; after bioslurry treatment, it was noticed a shift in the microbial community composition, with Proteobacteria phylum dominating the remediation environment (high increase in terms of growth for Hydrogenophaga and Sphingorhabdus genera) along with the Phaeodactylibacter genus (Bacteroidetes). Furthermore, the assessment of gaseous emissions from the system allowed to quantify the volatile hydrocarbon component and, consequently, to obtain a more accurate evaluation of TPH-removal pathway by the bioslurry system. Finally, phytotoxicity tests on sediment samples highlighted an increase of the treated sample quality status compared to the untreated one.
Asunto(s)
Microbiota , Petróleo , Contaminantes del Suelo , Biodegradación Ambiental , Sedimentos Geológicos/química , Hidrocarburos/metabolismo , Petróleo/análisis , Microbiología del Suelo , Contaminantes del Suelo/análisisRESUMEN
BACKGROUND: Limited real-world data exist on the effectiveness and safety of abiraterone acetate plus prednisone (abiraterone hereafter) in the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) naive to chemotherapy. Most of the few available studies had a retrospective design and included a small number of patients. In the interim analysis of the ABItude study, abiraterone showed good clinical effectiveness and safety profile in the chemotherapy-naive setting over a median follow-up of 18 months. PATIENTS AND METHODS: We evaluated clinical and patient-reported outcomes (PROs) of chemotherapy-naive mCRPC patients treated with abiraterone as for clinical practice in the Italian, observational, prospective, multicentric ABItude study. mCRPC patients were enrolled at abiraterone start (February 2016-June 2017) and followed up for 3 years; clinical endpoints and PROs, including quality of life (QoL) and pain, were prospectively collected. Kaplan-Meier curves were estimated. RESULTS: Of the 481 patients enrolled, 454 were assessable for final study analyses. At abiraterone start, the median age was 77 years, with 58.6% elderly patients and 69% having at least one comorbidity (57.5% cardiovascular diseases). Visceral metastases were present in 8.4% of patients. Over a median follow-up of 24.8 months, median progression-free survival (any progression reported by the investigators), time to abiraterone discontinuation, and overall survival were, respectively, 17.3 months [95% confidence interval (CI) 14.1-19.4 months], 16.0 months (95% CI 13.1-18.2 months), and 37.3 months (95% CI 36.5 months-not estimable); 64.2% of patients achieved ≥50% reduction in prostate-specific antigen. QoL assessed by Functional Assessment of Cancer Therapy-Prostate, the European Quality of Life 5 Dimensions 3 Level, and European Quality of Life Visual Analog Scale remained stable during treatment. Median time to pain progression according to Brief Pain Inventory data was 31.1 months (95% CI 24.8 months-not estimable). Sixty-two patients (13.1%) had at least one adverse drug reaction (ADR) and 8 (1.7%) one serious ADR. CONCLUSION: With longer follow-up, abiraterone therapy remains safe, well tolerated, and active in a large unselected population.
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Acetato de Abiraterona , Neoplasias de la Próstata Resistentes a la Castración , Acetato de Abiraterona/farmacología , Acetato de Abiraterona/uso terapéutico , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Humanos , Masculino , Dolor/inducido químicamente , Dolor/tratamiento farmacológico , Prednisona/farmacología , Prednisona/uso terapéutico , Estudios Prospectivos , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/patología , Calidad de Vida , Estudios RetrospectivosRESUMEN
One of the challenges to implementing the modeling of the biological reductive dechlorination (RD) process is the evaluation of biological parameters that represent the abundance/activity levels of the microorganisms involved in the biodegradation of chloroethenes. Here we report a combined analysis of kinetic and specific biomass parameters conducted on three dechlorinating consortia enriched on PCE, TCE and cis-1,2-DCE. In these consortia, Dehalococcoides mccartyi (Dhc) represented ≥70% of the bacterial population identified via 16S rRNA gene amplicon sequencing. Quantitative biomolecular methods were used to generate specific biomass parameters targeting either the Dhc population (16S rRNA genes or cells) or specific genes encoding RD process-involved reductive dehalogenases. The correlation factor between the abundance of active Dhc cells or tceA gene copies and maximum RD rates allowed to predict an increment of 7E+09 of active Dhc cells or 5E+09 tceA gene copies/L under controlled conditions. Diversely, the utilization of gene transcripts as biomass parameters for RD modeling did not provide reliable correlations with kinetic performances. This study provides valuable insights for further modeling of the RD process through the utilization of specific biomass parameters.
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Chloroflexi , Tricloroetileno , Cloruro de Vinilo , Biodegradación Ambiental , Biomasa , Chloroflexi/genética , Dehalococcoides , ARN Ribosómico 16S/genéticaRESUMEN
Pollution of aquatic ecosystems by plastic wastes poses severe environmental and health problems and has prompted scientific investigations on the fate and factors contributing to the modification of plastics in the marine environment. Here, we investigated, by means of microcosm studies, the role of hydrocarbon-degrading bacteria in the degradation of poly(ethylene terephthalate) (PET), the main constituents of plastic bottles, in the marine environment. To this aim, different bacterial consortia, previously acclimated to representative hydrocarbons fractions namely, tetradecane (aliphatic fraction), diesel (mixture of hydrocarbons), and naphthalene/phenantrene (aromatic fraction), were used as inocula of microcosm experiments, in order to identify peculiar specialization in poly(ethylene terephthalate) degradation. Upon formation of a mature biofilm on the surface of poly(ethylene terephthalate) films, the bacterial biodiversity and degradation efficiency of each selected consortium was analyzed. Notably, significant differences on biofilm biodiversity were observed with distinctive hydrocarbons-degraders being enriched on poly(ethylene terephthalate) surface, such as Alcanivorax, Hyphomonas, and Cycloclasticus species. Interestingly, ATR-FTIR analyses, supported by SEM and water contact angle measurements, revealed major alterations of the surface chemistry and morphology of PET films, mainly driven by the bacterial consortia enriched on tetradecane and diesel. Distinctive signatures of microbial activity were the alteration of the FTIR spectra as a consequence of PET chain scission through the hydrolysis of the ester bond, the increased sample hydrophobicity as well as the formation of small cracks and cavities on the surface of the film. In conclusion, our study demonstrates for the first time that hydrocarbons-degrading marine bacteria have the potential to degrade poly(ethylene terephthalate), although their degradative activity could potentially trigger the formation of harmful microplastics in the marine environment.
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Plásticos , Tereftalatos Polietilenos , Bacterias , Biodegradación Ambiental , Ecosistema , Etilenos , Hidrocarburos , Ácidos FtálicosRESUMEN
OBJECTIVE: Whether lymph node dissection (LND) should be performed concomitantly with radical nephrectomy (RN) for non-metastatic renal carcinoma has still been controversial recently. We conducted a meta-analysis assessing oncologic outcomes of radical nephrectomy with lymph node dissection (LND) and without lymph node dissection (non-LND) in non-metastatic renal cell carcinoma (NMRCC). PATIENTS AND METHODS: A systematic review was performed until April 2018 using a comprehensive search in PubMed, EMBASE, and Cochrane Library databases to identify eligible comparative studies. A formal meta-analysis was performed for studies comparing radical nephrectomy with LND and radical nephrectomy with non-LND for cT1-T4NxM0 tumors. Furthermore, a subgroup analysis for locally advanced renal cell carcinoma (cT3-T4NxM0) was conducted. RESULTS: Thirteen studies on patients with LND and non- LND were identified and included in the analysis. LND group did not have a significantly better survival than non-LND group for cT1-T4NxM0 tumors (HR 0.93, 95% CI 0.78-1.11, p=0.45), However, in the subgroup of locally advanced renal cell carcinoma (cT3-T4NxM0), it showed a significantly better OS rate in patients who had undergone LND compared to those without LND (HR 0.73, 95% CI 0.60-0.90; p=0.003). CONCLUSIONS: LND offers better cancer control and better long-term survival in locally advanced renal cell carcinomas (cT3-T4NxM0). This conclusion should be confirmed by a prospective randomized clinical trial.
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Carcinoma de Células Renales/cirugía , Neoplasias Renales/cirugía , Escisión del Ganglio Linfático/métodos , Carcinoma de Células Renales/patología , Femenino , Humanos , Neoplasias Renales/patología , Masculino , Estadificación de Neoplasias , Nefrectomía , Estudios Prospectivos , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
OBJECTIVE: Testicular cancer is a relatively rare neoplasia, with an incidence of about 1,5% among male malignancies, usually in the third and fourth decade of life. Although several histological variants are known, with some histotypes affecting older patients (e.g., spermatocytic seminoma), there is a clear predominance (90-95%) of germ cell tumors among young adults patients1. Testicular Germ Cell Tumor (TGCT), undoubtedly the seminoma histological variant more than non-seminoma one, is definitely a highly curable disease, with a distinctive sensitivity to cisplatin-based therapy (and for seminomas to radiotherapy) and an outstanding cure rate of nearly 80% even for patients with advanced disease. So far, clinical and pathohistological features supported our efforts to choose the best treatment option for patients suffering from this malignancy, but we don't clearly enough know molecular and pathological features underlying different clinical behaviors, mostly in early-stage disease: by improving this knowledge, we should better "shape" therapeutic or surveillance programs for each patient, also in order to avoid unnecessary, if not harmful, treatments.
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Neoplasias Testiculares/patología , Antineoplásicos/uso terapéutico , Cisplatino/uso terapéutico , Humanos , Masculino , Estadificación de Neoplasias , Neoplasias de Células Germinales y Embrionarias/tratamiento farmacológico , Neoplasias de Células Germinales y Embrionarias/metabolismo , Neoplasias de Células Germinales y Embrionarias/patología , Pronóstico , Seminoma/metabolismo , Seminoma/patología , Seminoma/radioterapia , Neoplasias Testiculares/tratamiento farmacológico , Neoplasias Testiculares/metabolismoRESUMEN
Marine sediments represent an important sink of harmful petroleum hydrocarbons after an accidental oil spill. Electrobioremediation techniques, which combine electrokinetic transport and biodegradation processes, represent an emerging technological platform for a sustainable remediation of contaminated sediments. Here, we describe the results of a long-term mesocosm-scale electrobioremediation experiment for the treatment of marine sediments contaminated by crude oil. A dimensionally stable anode and a stainless-steel mesh cathode were employed to drive seawater electrolysis at a fixed current density of 11 A/m2. This approach allowed establishing conditions conducive to contaminants biodegradation, as confirmed by the enrichment of Alcanivorax borkumensis cells harboring the alkB-gene and other aerobic hydrocarbonoclastic bacteria. Oil chemistry analyses indicated that aromatic hydrocarbons were primarily removed from the sediment via electroosmosis and low molecular weight alkanes (nC6 to nC10) via biodegradation.
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Contaminación por Petróleo , Petróleo , Biodegradación Ambiental , Sedimentos Geológicos , Hidrocarburos , Agua de MarRESUMEN
BACKGROUND: Individuals with Down syndrome generally show a floor effect on Wechsler Scales that is manifested by flat profiles and with many or all of the weighted scores on the subtests equal to 1. METHOD: The main aim of the present paper is to use the statistical Hessl method and the extended statistical method of Orsini, Pezzuti and Hulbert with a sample of individuals with Down syndrome (n = 128; 72 boys and 56 girls), to underline the variability of performance on Wechsler Intelligence Scale for Children-Fourth Edition subtests and indices, highlighting any strengths and weaknesses of this population that otherwise appear to be flattened. RESULTS: Based on results using traditional transformation of raw scores into weighted scores, a very high percentage of subtests with weighted score of 1 occurred in the Down syndrome sample, with a floor effect and without any statistically significant difference between four core Wechsler Intelligence Scale for Children-Fourth Edition indices. The results, using traditional transformation, confirm a deep cognitive impairment of those with Down syndrome. Conversely, using the new statistical method, it is immediately apparent that the variability of the scores, both on subtests and indices, is wider with respect to the traditional method. CONCLUSION: Children with Down syndrome show a greater ability in the Verbal Comprehension Index than in the Working Memory Index.
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Trastornos del Conocimiento/complicaciones , Trastornos del Conocimiento/diagnóstico , Síndrome de Down/complicaciones , Escalas de Wechsler/estadística & datos numéricos , Adolescente , Niño , Trastornos del Conocimiento/psicología , Síndrome de Down/psicología , Femenino , Humanos , Italia , Masculino , Psicometría , Reproducibilidad de los ResultadosRESUMEN
Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure. A broad evaluation of the most relevant biofilm monitoring and control strategies currently used or potentially useful in cooling water systems is also provided.
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Biopelículas/crecimiento & desarrollo , Agua Dulce/microbiología , Legionella pneumophila/fisiología , Microbiología del Agua , Abastecimiento de AguaRESUMEN
OBJECTIVE: In this review, we focused our attention on Quality of Life (QoL) of testicular cancer survivors (TCSs), in general and in the most relevant areas. Several key findings have been highlighted in our review. MATERIALS AND METHODS: PubMed, MEDLINE and PsycINFO databases were consulted to find published studies, from 1980 to May 2017, that met our inclusion criteria. RESULTS: The majority of studies investigated older adult TCSs, while few studies on adolescent and young adult patients were available. Many studies indicate that health-related QoL (HRQoL) is similar among the TCSs and the general population. Even if QoL deteriorates so clear at the time of diagnosis and throughout treatment, afterward returns to normal levels, as defined by the matched controls. However, there are numerous chronic conditions consequent to diagnosis and treatment of testicular cancer that plague survivors and affect QoL, like Raynaud-like phenomena, peripheral neuropathy, fatigue, anxiety, sexual, fertility and body image problems. Even if these problems can have no effects on the measures of global QoL, they have an impact on the quality of life. Differences between TCSs with and without a partner bring to different outcomes in the adjustments to cancer. CONCLUSIONS: It is necessary to identify TCSs with higher risks of poorer QoL outcomes, to focus interventions on the areas with the greatest impairments. Further researches should consider the effects of testicular cancer on the impaired areas, collecting more data to better identify survivor's needs and consequent interventions, with a special focus on adolescent and young adult TCSs. Other works are requested on therapies, preventive and ameliorative, to reduce chronic side effects of testicular cancer treatment.
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Supervivientes de Cáncer/psicología , Calidad de Vida , Neoplasias Testiculares/complicaciones , Neoplasias Testiculares/psicología , Enfermedad Crónica , Humanos , MasculinoRESUMEN
Methanogenic biomass plays a key role with regard to methane production during anaerobic bioconversion of organic substrates. In this study, the effect of two different acclimated inocula on digestion performances was investigated by means of anaerobic batch tests on untreated and sonicated waste-activated sludge. Organics solubilization and removal kinetics, the abundance and physiological conditions of archaeal cells on ultimate methane yield were evaluated. The simultaneous presence of Methanosarcina and Methanosaeta in the archaeal biomass, the higher initial archaeal cells relative abundance and their occurrence in the aggregated forms were the main factors positively affecting the conversion into methane. The presence of the acclimated inoculum at the start-up influenced positively the methane improvement due to sonication, and the methane-specific production increased from 0.335 ± 0.03 to 0.420 ± 0.05â Nm3/kg VSfed. Moreover, the better physiological state of methanogens permitted to appreciate the effect of hydrolysis improvement by ultrasound pretreatment.
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Reactores Biológicos , Metano/química , Aguas del Alcantarillado , Aclimatación , Anaerobiosis , BiomasaRESUMEN
Biofilms commonly colonise cooling water systems, causing equipment damage and interference with the operational requirements of the systems. In this study, next-generation sequencing (NGS), catalysed reporter deposition fluorescence in situ hybridisation (CARD-FISH), lectin staining and microscopy were used to evaluate temporal dynamics in the diversity and structure of biofilms collected seasonally over one year from an open full-scale cooling tower. Water samples were analysed to evaluate the contribution of the suspended microorganisms to the biofilm composition and structure. Alphaproteobacteria dominated the biofilm communities along with Beta- and Gammaproteobacteria. The phototrophic components were mainly cyanobacteria, diatoms and green algae. Bacterial biodiversity decreased from winter to autumn, concurrently with an increase in cyanobacterial and microalgal richness. Differences in structure, spatial organisation and glycoconjugates were observed among assemblages during the year. Overall, microbial variation appeared to be mostly affected by irradiance and water temperature rather than the source of the communities. Variations in biofilms over seasons should be evaluated to develop specific control strategies.
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Biopelículas/crecimiento & desarrollo , Chlorophyta/crecimiento & desarrollo , Cianobacterias/crecimiento & desarrollo , Diatomeas/crecimiento & desarrollo , Proteobacteria/crecimiento & desarrollo , Estaciones del Año , Biodiversidad , Frío , Hibridación Fluorescente in Situ , Industria del Petróleo y Gas , Propiedades de SuperficieRESUMEN
In this study, next generation sequencing and catalyzed reporter deposition fluorescence in situ hybridization, combined with confocal microscopy, were used to provide insights into the biodiversity and structure of biofilms collected from four full-scale European cooling systems. Water samples were also analyzed to evaluate the impact of suspended microbes on biofilm formation. A common core microbiome, containing members of the families Sphingomonadaceae, Comamonadaceae and Hyphomicrobiaceae, was found in all four biofilms, despite the water of each coming from different sources (river and groundwater). This suggests that selection of the pioneer community was influenced by abiotic factors (temperature, pH) and tolerances to biocides. Members of the Sphingomonadaceae were assumed to play a key role in initial biofilm formation. Subsequent biofilm development was driven primarily by light availability, since biofilms were dominated by phototrophs in the two studied 'open' systems. Their interactions with other microbial populations then shaped the structure of the mature biofilm communities analyzed.
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Biodiversidad , Biopelículas/clasificación , Microbiota/genética , Desinfectantes/farmacología , Industria Farmacéutica , Agua Subterránea/microbiología , Secuenciación de Nucleótidos de Alto Rendimiento , Hibridación Fluorescente in Situ , Pruebas de Sensibilidad Microbiana , Microbiota/efectos de los fármacos , Industria del Petróleo y Gas , Ríos/microbiologíaRESUMEN
OBJECTIVE: The aim of our report was to review the literature concerning the toxicity of radiation therapy in patients treated for high-risk prostate cancer, and to evaluate the differences in toxicity between conventional fractionation and hypofractionated treatments, in view of different techniques used in high-risk prostate cancer patients. MATERIALS AND METHODS: PubMed database has been explored for studies concerning acute and late urinary/gastrointestinal toxicity in high-risk prostate cancer patients treated with radiotherapy. Prospective studies, concerning potential relationship between acute/late genitourinary (GU)/gastrointestinal (GI) toxicity and prostate radiotherapy in patients with high-risk prostate cancer, were included in the final analysis. Data collected from single arm, phase II non-randomized and randomized studies have been evaluated to perform odds ratio for toxicity risk. Furthermore, meta-analysis randomized prospective trials were considered suitable because they had recruited high-risk prostate cancer patients who didn't undergo surgery, with available data on ≥ G2 toxicity frequency. RESULTS: The initial search provided 606 results, but only 35 manuscripts met all eligibility requirements and were included in this report. In order to perform odds ratio we observed a decrease in late gastrointestinal toxicity for patients treated with hypofractionated schemes compared to CV treated ones. Among patients who underwent conventional treatment, SIB seemed to decrease acute genitourinary side effects; SIB-Hypo treated patients suffered less toxicity than patients treated with hypofractionated- sequential boost schemes. Hypo-SIB schemes would seem less toxic in terms of acute gastrointestinal and late genitourinary side effects than CV-SIB. Therefore, our focus shifted to 6 clinical trials evaluating genitourinary and gastrointestinal toxicity in patients who had been randomized to receive conventional fractionation or hypofractionated treatment, in both cases with IMRT technology. Our meta-analysis of these randomized trials involving patients with high-risk prostate cancer showed a statistically significant increase in late genitourinary toxicity for hypo-treated patients; no difference was observed in acute genitourinary/gastrointestinal toxicity, and in late gastrointestinal toxicity. CONCLUSIONS: Our analysis doesn't want to establish a definitive truth; very few trials assessed only high risk-class patients. Our purpose is to stimulate further randomized prospective trials focusing both on the effectiveness and toxicity profile (toxicity/effectiveness ratio), taking into account the use of different technologies and doses.
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Neoplasias de la Próstata/radioterapia , Traumatismos por Radiación/etiología , Fraccionamiento de la Dosis de Radiación , Enfermedades Gastrointestinales/etiología , Humanos , Masculino , Radioterapia de Intensidad Modulada , Ensayos Clínicos Controlados Aleatorios como Asunto , Recto/patologíaRESUMEN
OBJECTIVE: Hypersensitivity reactions (HSR) are frequently reported in patients rechallenged with carboplatin for recurrent ovarian cancer (ROC) and represent a critical issue, since discontinuation of the platinum-based therapy could affect prognosis. Several strategies to allow platinum rechallenge have been described, with controversial outcomes. The aim of this study is to illustrate a 10-year experience with cisplatin in patients with a previous HSR to carboplatin or at risk for allergy. METHODS: A retrospective review of all patients with platinum sensitive ROC retreated with carboplatin was performed between January 2007 and May 2016 at the Istituto Nazionale Tumori, Fondazione "G. Pascale", Naples. RESULTS: Among 183 patients, 49 (26.8%) presented HSR to carboplatin, mainly during second line therapy. Mean number of cycles before HSR was 8 (range 3-17). G2, G3 and G4 reaction were detected in 83%, 15% and 2% of patients, respectively. In a multivariate analysis including age, hystotype, BRCA status, previous known HSR, and combination drug administered, only the type of carboplatin-based doublet used as 2nd line therapy was found to significantly affect HSR development, with a protective effect of PLD (pegylated liposomal doxorubicin) (p = 0.014, OR = 0.027). Thirty seven patients (77%) with a previous HSR to carboplatin were rechallenged with cisplatin. Treatment was generally well tolerated. 5 patients (13.1%) experienced mild HSR to cisplatin, successfully managed in all cases. 14 patients were treated with cisplatin even without a carboplatin-related HSR due to other allergies. Among these, only one developed HSR (7.1%). CONCLUSIONS: Cisplatin rechallenge is a feasible approach in patients experiencing HSR to carboplatin to maintain the beneficial effect of platinum while reducing hypersensitivity-related risks.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carboplatino/efectos adversos , Cisplatino/administración & dosificación , Hipersensibilidad a las Drogas/etiología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Neoplasias Ováricas/tratamiento farmacológico , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Carboplatino/administración & dosificación , Carboplatino/inmunología , Cisplatino/efectos adversos , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Doxorrubicina/administración & dosificación , Doxorrubicina/análogos & derivados , Femenino , Humanos , Persona de Mediana Edad , Paclitaxel/administración & dosificación , Polietilenglicoles/administración & dosificación , Estudios Retrospectivos , GemcitabinaRESUMEN
The present study evaluates the PCB-dehalorespiring capabilities and dynamics of indigenous Dehalococcoides mccartyi population in a PCB contaminated marine sediment. Specialized PCB-dechlorinase genes pcbA1, pcbA4 and pcbA5 previously characterized in pure cultures of D. mccartyi, were here found for the first time in environmental samples. Reductive dechlorination was stimulated by spiking Aroclor1254 to the sediment and by imposing strictly anaerobic conditions both with and without bioaugmentation with a Dehalococcoides mccartyi enrichment culture. In line with the contaminant dechlorination kinetics, Dehalococcoides population increased during the entire incubation period showing growth yields of 4.94E+07 Dehalococcoides per µmolCl-1 and 7.30E+05 Dehalococcoides per µmolCl-1 in the marine sediment with and without bioaugmentation respectively. The pcbA4 and pcbA5 dechlorinase genes, and to a lesser extent pcbA1 gene, were enriched during the anaerobic incubation suggesting their role in Aroclor1254 dechlorination under salinity conditions.
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Proteínas Bacterianas/genética , Chloroflexi/genética , Sedimentos Geológicos/microbiología , Bifenilos Policlorados/metabolismo , Proteínas Bacterianas/metabolismo , Biodegradación Ambiental , Chloroflexi/metabolismo , Halogenación , Consorcios Microbianos/genética , Bifenilos Policlorados/química , Contaminantes Químicos del Agua/químicaRESUMEN
Chlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination (RD) processes, including Dehalococcoides mccartyi (Dhc), are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene (PCE), used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L(-1) d(-1). Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L(-1)d(-1) within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells (growth yield of ~7.0 E + 07 Dhc cells per µM Cl(-1) released). Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study (2.41 E + 05 tceA gene transcripts g(-1)). Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non-Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD process.
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Sedimentos Geológicos/microbiología , Agua de Mar/microbiología , Tetracloroetileno/metabolismo , Contaminantes Químicos del Agua/metabolismo , Biodegradación Ambiental , Biodiversidad , Chloroflexi/clasificación , Chloroflexi/genética , Sedimentos Geológicos/química , Halogenación , Hibridación Fluorescente in Situ , Agua de Mar/química , Tetracloroetileno/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Thermophilic bacteria have been isolated from several terrestrial, marine and industrial environments. Anaerobic digesters treating organic wastes are often an important source of these microorganisms, which catalyze a wide array of metabolic processes. Moreover, organic wastes are primarily composed of proteins, whose degradation is often incomplete. Coprothermobacter spp. are proteolytic anaerobic thermophilic microbes identified in several studies focused on the analysis of the microbial community structure in anaerobic thermophilic reactors. They are currently classified in the phylum Firmicutes; nevertheless, several authors showed that the Coprothermobacter group is most closely related to the phyla Dictyoglomi and Thermotoga. Since only a few proteolytic anaerobic thermophiles have been characterized so far, this microorganism has attracted the attention of researchers for its potential applications with high-temperature environments. In addition to proteolysis, Coprothermobacter spp. showed several metabolic abilities and may have a biotechnological application either as source of thermostable enzymes or as inoculum in anaerobic processes. Moreover, they can improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea. To gain a better understanding of the phylogenesis, metabolic capabilities and adaptations of these microorganisms, it is of importance to better define the role in thermophilic environments and to disclose properties not yet investigated.
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Fermentación/genética , Péptido Hidrolasas/genética , Thermoanaerobacter , Reactores Biológicos/microbiología , Biotecnología , Ecología , Fermentación/fisiología , Genoma Bacteriano/genética , Péptido Hidrolasas/metabolismo , Filogenia , Proteolisis , ARN Ribosómico 16S/genética , Temperatura , Thermoanaerobacter/clasificación , Thermoanaerobacter/genética , Thermoanaerobacter/metabolismoRESUMEN
Due to the direct involvement in the biodegradation of chlorinated solvents, reductive dehalogenase genes (RDase) are considered biomarkers of the metabolic potential of different strains of Dehalococcoides mccartyi (Dhc). This is known to be the only microbe able to completely reduce toxic chlorinated solvents to harmless ethene. In the last years, several Molecular Biological Tools (MBTs) have been developed to optimize the detectability of Dhc cells and/or the RDase genes, with particular attention to the most important indicators of ethene formation, namely tceA and vcrA genes. Despite qPCR has been indicated as the MBT of choice, the use of CARD-FISH recently demonstrated to provide a more accurate quantification of Dhc cells in a wide concentration range, overcoming the drawbacks of loosing nucleic acids during the preparation of the sample associated with qPCR. CARD-FISH assays usually target 16S rRNA and up to date no protocol able to discriminate different Dhc strains by detecting RDase genes has been developed. This study reports the first evidence of in situ detection of tceA and vcrA genes into Dhc cells by applying a new procedure named geneCARD-FISH. Dhc strains carrying tceA and vcrA genes were identified and quantified in a PCE-to-ethene dechlorinating microbial enrichment and overall they represented 58.63%±2.45% and 40.46%±1.86% of the total Dhc cells, respectively. These values were markedly higher than those obtained by qPCR, which strongly underestimated the actual concentration of vcrA gene (0.08%±0.01% of Dhc 16S rRNA gene copies). The assay was successfully applied also for the analysis of environmental samples and remarkably strengthens the biomonitoring activities at field scale by providing the specific in situ discrimination of Dhc cells carrying the key-RDase genes.