Methanotrophs: Discoveries, Environmental Relevance, and a Perspective on Current and Future Applications

Methane is the final product of the anaerobic decomposition of organic matter. The conversion of organic matter to methane (methanogenesis) as a mechanism for energy conservation is exclusively attributed to the archaeal domain. Methane is oxidized by methanotrophic microorganisms using oxygen or alternative terminal electron acceptors. Aerobic methanotrophic bacteria belong to the phyla Proteobacteria and Verrucomicrobia, while anaerobic methane oxidation is also mediated by more recently discovered anaerobic methanotrophs with representatives in both the bacteria and the archaea domains. The anaerobic oxidation of methane is coupled to the reduction of nitrate, nitrite, iron, manganese, sulfate, and organic electron acceptors (e.g., humic substances) as terminal electron acceptors. This review highlights the relevance of methanotrophy in natural and anthropogenically influenced ecosystems, emphasizing the environmental conditions, distribution, function, co-existence, interactions, and the availability of electron acceptors that likely play a key role in regulating their function. A systematic overview of key aspects of ecology, physiology, metabolism, and genomics is crucial to understand the contribution of methanotrophs in the mitigation of methane efflux to the atmosphere. We give significance to the processes under microaerophilic and anaerobic conditions for both aerobic and anaerobic methane oxidizers. In the context of anthropogenically influenced ecosystems, we emphasize the current and potential future applications of methanotrophs from two different angles, namely methane mitigation in wastewater treatment through the application of anaerobic methanotrophs, and the biotechnological applications of aerobic methanotrophs in resource recovery from methane waste streams. Finally, we identify knowledge gaps that may lead to opportunities to harness further the biotechnological benefits of methanotrophs in methane mitigation and for the production of valuable bioproducts enabling a bio-based and circular economy

Effect of Temperature on N2O and NO Emission in a Partial Nitrification SBR Treating Reject Wastewater

Temperature is a very important parameter during nitritation, having a direct effect on ammonia oxidation rate (AOR) and enzymatic activities which relate to both N2O and NO emission. This study aims at investigating the effect of temperature on AOR, N2O and NO production in an enriched ammonia oxidizing bacteria (AOB) sequencing batch reactor (SBR) performing partial nitrification (PN) of synthetic reject wastewater. To achieve that, a SBR was subject to several shifts in temperature (in the range of 30 to 15 \ub0C, 5 \ub0C for each decrease). Cycle studies, which contain two aeration phases, were conducted under each temperature. The results showed that AOR specific exponentially correlates with the temperature during the temperature decreasing experiments. With the decrease of the temperature, N2O firstly increased and then dropped to very low levels along with the decrease of the AOR, unlike NO that did not show any apparent connection with the temperature

Antibiotic prophylaxis before dental procedures to prevent infective endocarditis: a systematic review

Purpose: Infective endocarditis (IE) is a severe bacterial infection. As a measure of prevention, the administration of antibiotic prophylaxis (AP) prior to dental procedures was recommended in the past. However, between 2007 and 2009, guidelines for IE prophylaxis changed all around the word, limiting or supporting the complete cessation of AP. It remains unclear whether AP is effective or not against IE. Methods: We conducted a systematic review whether the administration of AP in adults before any dental procedure, compared to the non-administration of such drugs, has an effect on the risk of developing IE. We searched for studies in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via OVID, and EMBASE. Two different authors filtered articles independently and data extraction was performed based on a pre-defined protocol. Results: The only cohort study meeting our criteria included patients at high-risk of IE. Analysis of the extracted data showed a non-significant decrease in the risk of IE when high-risk patients take AP prior to invasive dental procedures (RR 0.39, p-value 0.11). We did not find other studies including patients at low or moderate risk of IE. Qualitative evaluation of the excluded articles reveals diversity of results and suggests that most of the state-of-the-art articles are underpowered. Conclusions: Evidence to support or discourage the use of AP prior to dental procedures as a prevention for IE is very low. New high-quality studies are needed, even though such studies would require big settings and might not be immediately feasible. Keywords: Antibiotic prophylaxis prior dental procedure; Dental procedure; Endocarditis guidelines; Endocarditis prophylaxis; High-risk patients; Infective endocarditis

Anomalous left coronary artery from the pulmonary artery (ALCAPA) diagnosed in adulthood: varied clinical presentation, therapeutic approach and outcome

Introduction The diagnosis of ALCAPA syndrome is sporadic in adulthood, of the limited cases in the literature most are incidental or without symptoms. There is a broad spectrum of clinical manifestations of ALCAPA syndrome however, including sudden cardiac death. Cases We present herewith a series of 12 consecutive patients with ALCAPA, all diagnosed in adulthood (between 18 and 73 years of age). Five patients developed symptoms (breathlessness) after the fourth decade of life, 3 were undiagnosed despite a history of previous mitral valve repair, one presented with heart failure, one with resuscitated cardiac arrest, whereas two patients were asymptomatic. We review in this paper, the clinical history, diagnostic approach and therapeutic choices of ALCAPA syndrome. Conclusion ALCAPA syndrome is not confined to childhood, late diagnosis in adulthood has a varied clinical presentation. ALCAPA syndrome should be particularly considered as a potential, albeit uncommon cause of mitral regurgitation and/or dilated cardiomyopathy

Peptide gels of fully-defined composition and mechanics for probing cell-cell and cell-matrix interactions in vitro

© 2019 Current materials used for in vitro 3D cell culture are often limited by their poor similarity to human tissue, batch-to-batch variability and complexity of composition and manufacture. Here, we present a “blank slate” culture environment based on a self-assembling peptide gel free from matrix motifs. The gel can be customised by incorporating matrix components selected to match the target tissue, with independent control of mechanical properties. Therefore the matrix components are restricted to those specifically added, or those synthesised by encapsulated cells. The flexible 3D culture platform provides full control over biochemical and physical properties, allowing the impact of biochemical composition and tissue mechanics to be separately evaluated in vitro. Here, we demonstrate that the peptide gels support the growth of a range of cells including human induced pluripotent stem cells and human cancer cell lines. Furthermore, we present proof-of-concept that the peptide gels can be used to build disease-relevant models. Controlling the peptide gelator concentration allows peptide gel stiffness to be matched to normal breast (1 kPa), with higher stiffness favouring the viability of breast cancer cells over normal breast cells. In parallel, the peptide gels may be modified with matrix components relevant to human breast, such as collagen I and hyaluronan. The choice and concentration of these additions affect the size, shape and organisation of breast epithelial cell structures formed in co-culture with fibroblasts. This system therefore provides a means of unravelling the individual influences of matrix, mechanical properties and cell-cell interactions in cancer and other diseases

Metastatic gallbladder adenocarcinoma with signet-ring cells: A case report

<p>Abstract</p> <p>Introduction</p> <p>Signet-ring cell carcinoma is a rare and aggressive variant of mucinous adenocarcinoma. Only a few cases of gallbladder adenocarcinoma with signet-ring cells have been reported and because of this there is a lack of knowledge about the behavior and biology of this pathology.</p> <p>Case presentation</p> <p>We present the case of a 63-year-old Arab man with gallbladder signet-ring cell adenocarcinoma. He had an elective cholecystectomy and refused chemotherapy. Two months later, a small hepatic metastatic nodule was found, and nine months later he presented with multiple metastases in the liver, lymphatic nodes, both pleuras, peritoneum and subcutaneous tissue.</p> <p>Conclusion</p> <p>The proliferation of signet-ring cells in a gallbladder adenocarcinoma worsens the prognosis of an already adverse neoplasm. New lines of treatment in chemotherapy, such as cisplatin, or new biological therapy, such as monoclonal antibody c-myc oncogene, should be encouraged to improve the survival and life quality of these oncologic patients.</p

Informe Final: Projecte 2020PID-UB/017

Projecte: 2020PID-UB/017En aquest projecte s’ha explorat i utilitzat les eines del paquet d’R exams per tal de generar activitats personalitzades per als alumnes de l’assignatura de Disseny d’Experiments del grau interuniversitari UB-UPC d’Estadística. El paquet exams permet crear qüestionaris que incorporen preguntes de tipus test, numèriques o una barreja d’ambdues. Mitjançant codi R es poden generar aleatòriament diferents conjunts de dades i possibles respostes de tal manera i així els qüestionaris siguin únics per a cada alumne. Una altra avantatge que ofereix el paquet exams és que en integrar-se al Moodle un cop finalitzat el qüestionari la nota queda integrada automàticament a la base de dades de qualificacions. A més, l’alumne veu immediatament la nota i quins errors ha comès i les solucions de cada resposta. Tot i que els professors no teníem experiència prèvia amb el paquet exams, no ha sigut difícil confeccionar les preguntes ni tampoc integrar-les a la plataforma del campus virtual a través del Moodle. Al contrari, aquest procés ha resultat senzill i no hem trobat cap dificultat tècnica. L’alumnat ha respost de forma positiva, i han trobat gratificant el fet de saber la nota i els errors que havien comés en acabar el qüestionari. Per aquest motiu, creiem que l’ús del paquet exams com a part de la docència de l’assignatura és molt positiva i planegem continuar usant-lo tot explorant noves funcionalitats que ofereixi aquesta eina. Per últim, pensem que la utilització d’exams es podria estendre també a altres assignatures de anàlisis de dades i d’altres graus, com de fet s’està realitzant a l’assignatura de Disseny d’Experiments i Anàlisis de Dades (DEAD) del grau de Biomedicin