A laboratory experiment for science courses: Sedimentary microbial fuel cells.

Nowadays there is a concern to improve the quality of education by including an interdisciplinary approach of concepts and their integration in the curriculum of scientific disciplines. The development of microbial fuel cells as a potential alternative for production of renewable energies gives undergraduate students the challenge of integrating interdisciplinary concepts in a hot topic of global interest as alternative energies. We present a laboratory experiment that has been part of a third-year undergraduate course in biology where students gained experience in assembling microbial fuel cells and the understanding of how they work. In this process, the students could integrate biological, biochemical, and electric concepts. In addition, the acquisition of manual skills and experimental design decisions are important for the development of future professionals.

Metabolism of Klebsiella pneumoniae freeze-dried cultures for the design of BOD bioassays.

AIMS: The survival rate of freeze-dried cultures is not enough information for technological applications of micro-organisms. There could be serious metabolic/structural damage in the survivors, leading to a delay time that can jeopardize the design of a rapid biochemical oxygen demand (BOD) metabolic-based bioassay. Therefore, we will study the metabolic activity (as ferricyanide reduction activity) and the survival rate (as colony-forming units, CFU) of different Klebsiella pneumoniae freeze-dried cultures looking for stable metabolic conditions after 35days of storage. METHOD AND RESULTS: Here, we tried several simple freeze-drying processes of Kl. pneumoniae. Electrochemical measurements of ferrocyanide and survival rates obtained with the different freeze-dried cultures were used to choose the best freeze-drying process that leads to a rapid metabolic-based bioassay. CONCLUSIONS: The use of milk plus monosodium glutamate was the best choice to obtain a Kl. pneumoniae freeze-dried culture with metabolic stable conditions after storage at -20°C without the need of vacuum storage and ready to use after 20min of rehydration. We also demonstrate that the viability and the metabolic activity are not always directly correlated. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that the use of this Kl. pneumoniae freeze-dried culture is appropriate for the design of a rapid BOD bioassay.

Voltamperometric discrimination of urea and melamine adulterated skimmed milk powder.

Nitrogen compounds like urea and melamine are known to be commonly used for milk adulteration resulting in undesired intoxication; a well-known example is the Chinese episode occurred in 2008. The development of a rapid, reliable and economic test is of relevance in order to improve adulterated milk identification. Cyclic voltammetry studies using an Au working electrode were performed on adulterated and non-adulterated milk samples from different independent manufacturers. Voltammetric data and their first derivative were subjected to functional principal component analysis (f-PCA) and correctly classified by the KNN classifier. The adulterated and non-adulterated milk samples showed significant differences. Best results of prediction were obtained with first derivative data. Detection limits in milk samples adulterated with 1% of its total nitrogen derived from melamine or urea were as low as 85.0 mg · L(-1) and 121.4 mg · L(-1), respectively. We present this method as a fast and robust screening method for milk adulteration analysis and prevention of food intoxication.

[Physical performance in patients with amyotrophic lateral sclerosis and its relationship with wheelchairs and walking aids use]. / Desempeño físico en pacientes con esclerosis lateral amiotrófica y su relación con el uso de silla de ruedas y ayuda para la marcha.

INTRODUCTION AND OBJECTIVES: Gait deficits and falls in patients with amyotrophic lateral sclerosis (ALS) restrict mobility. The aim of this study is to examine the appropriate use of walking aids and wheelchairs, based on the risk of falling and walking speed of patients with ALS. METHODS: Retrospective data from patients from the ALS clinic were included. Age, gender, evolution time, wheelchair use, walking aids, gait speed and the Berg Balance Scale were registered. Categorical variables were related to the Chi Square test and Fisher's exact test. RESULTS: Fifty eight patients met the inclusion criteria. Twenty-seven (46.55%) had adequate use of a wheelchair based on walking speed (p=.50). This association decreases to 6% in patients who walked at a speed lower than 0.88m/s. Forty-two (70.69%) had adequate use of an assistive device based on the risk of falls (p=.001). Of the subgroup with Berg Balance score ≤ 45, 38% did not use the appropriate device (p=.06). CONCLUSION: Patients with severe gait and balance deficits had inappropriate use of walking aids and/or wheelchairs. The findings of this study may mean a contribution that could be considered in the clinical evaluations of patients with ALS to minimize risks and improve the participation of this group of people.

Isolation and Characterization of a Novel Electrogenic Bacterium, Dietzia sp. RNV-4.

Electrogenic bacteria are organisms that can transfer electrons to extracellular electron acceptors and have the potential to be used in devices such as bioelectrochemical systems (BES). In this study, Dietzia sp. RNV-4 bacterium has been isolated and identified based on its biochemical, physiological and morphological characteristics, as well as by its 16S rRNA sequence analysis. Furthermore, the current density production and electron transfer mechanisms were investigated using bioelectrochemical methods. The chronoamperometric data showed that the biofilm of Dietzia sp. RNV-4 grew as the current increased with time, reaching a maximum of 176.6 ± 66.1 mA/m2 at the end of the experiment (7 d); this highly suggests that the current was generated by the biofilm. The main electron transfer mechanism, indicated by the cyclic voltammograms, was due to secreted redox mediators. By high performance liquid chromatography, canthaxanthin was identified as the main compound involved in charge transfer between the bacteria and the solid electrodes. Dietzia sp. RNV-4 was used as biological material in a microbial fuel cell (MFC) and the current density production was 299.4 ± 40.2 mA/m2. This is the first time that Dietzia sp. RNV-4 has been electrochemically characterized and identified as a new electrogenic strain.

[The lymphoid-like cells in blastic transformation of chronic myeloid leukemia]. / Le cellule "lymphoid like" nella trasformazione blastica della leucemia mieloide cronica.

The natural history of chornic myeloid leukaemia (CML) usually ends with a blastic transformation (BT). In 30% of cases, BT displays the cytomorphological, cytochemical, immunological and biochemical features and the response to therapy observed in acute lymphoblastic leukaemia (ALL). The presence of lymphoid-like cells in a blood disease classically interpreted as a disorder of the myeloid strain led to the suggestion that CML is a disease of a stem cell capable of displaying both myeloid and lymphoid characters. It is thought that this is due to the fact that the Ph1 alteration strikes a premyeloid and prelympoid stem cell that presents myeloid features in the chronic stage of CML and in myeloblastic BT, whereas it displays lymphoid characteristics in the lymphblastic BT of CML and Ph1+ ALL. This fact lends support to the unicystic haematopoietic theory of Ferrata. Reference is made to a case in which the BT of CML was marked by the predominant presence of cells with a lymphoblastic appearance.

Desempeño físico en pacientes con esclerosis lateral amiotrófica y su relación con el uso de silla de ruedas y ayuda para la marcha / Physical performance in patients with amyotrophic lateral sclerosis and its relationship with wheelchairs and walking aids use

Introducción y objetivos: El déficit de marcha y las caídas en pacientes con esclerosis lateral amiotrófica (ELA) restringen la movilidad. El objetivo de este estudio es examinar el uso apropiado de dispositivos de ayuda para la marcha y silla de ruedas para deambular basados en el riesgo de caídas y la velocidad de marcha de pacientes con ELA. Métodos: Se incluyeron datos retrospectivos de pacientes de la clínica ELA. Se registraron edad, género, tiempo de evolución, uso de silla de ruedas, dispositivo de ayuda para la marcha, velocidad de marcha y escala de Berg. Se relacionaron las variables categóricas con la prueba de chi cuadrado y test exacto de Fisher. Resultados: Cincuenta y ocho pacientes cumplieron con los criterios de inclusión. Veintisiete (46,55%) tuvieron uso adecuado de silla de ruedas basado en la velocidad de marcha (p=0,50). Esta asociación disminuye al 6% en pacientes que caminaron a velocidad menor a 0,88m/s. Cuarenta y dos (70,69%) tuvieron uso adecuado de dispositivo de ayuda para la marcha basado en el riesgo de caídas (P=0,001). Del subgrupo con puntaje de Berg ≤ 45, el 38% no empleó el dispositivo apropiado (p=0,06). Conclusiones: Los pacientes con severo déficit de equilibrio y de marcha tuvieron un uso inapropiado de dispositivos para caminar y/o silla de ruedas. Los hallazgos del presente estudio pueden significar un aporte que podría ser considerado en las evaluaciones clínicas de pacientes con ELA para minimizar los riesgos y mejorar la participación de este colectivo de personas.

Introduction and objectives: Gait deficits and falls in patients with amyotrophic lateral sclerosis (ALS) restrict mobility. The aim of this study is to examine the appropriate use of walking aids and wheelchairs, based on the risk of falling and walking speed of patients with ALS. Methods: Retrospective data from patients from the ALS clinic were included. Age, gender, evolution time, wheelchair use, walking aids, gait speed and the Berg Balance Scale were registered. Categorical variables were related to the Chi Square test and Fisher's exact test. Results: Fifty eight patients met the inclusion criteria. Twenty-seven (46.55%) had adequate use of a wheelchair based on walking speed (p=.50). This association decreases to 6% in patients who walked at a speed lower than 0.88m/s. Forty-two (70.69%) had adequate use of an assistive device based on the risk of falls (p=.001). Of the subgroup with Berg Balance score ≤ 45, 38% did not use the appropriate device (p=.06). Conclusion: Patients with severe gait and balance deficits had inappropriate use of walking aids and/or wheelchairs. The findings of this study may mean a contribution that could be considered in the clinical evaluations of patients with ALS to minimize risks and improve the participation of this group of people.(AU)

Assessing the effect of oxygen and microbial inhibitors to optimize ferricyanide-mediated BOD assay.

Methods for short-term BOD analysis (BOD(st)) based on ferricyanide mediator reduction have succeeded in overcoming some problems associated with the standard BOD test analysis (BOD(5)) such as long-term incubations (5 days), the need to dilute samples and low reproducibility. Here we present a bioassay where a Klebsiella pneumoniae environmental strain successfully reduces ferricyanide without de-aeration of the samples with linear BOD(5) ranges between 30 and 500 mg L(-1) or 30 and 200 mg L(-1), using glucose-glutamic acid solution (GGA) or OECD standards respectively. We further propose a new assay termination solution that allows higher reproducibility and standardization of the cell-based assay, employing formaldehyde (22.7 g L(-1)) or other compounds in order to stop ferricyanide reduction without affecting the amperometric detection and therefore replace the centrifugation step normally used to stop microbial-driven reactions in ferricyanide-mediated bioassays. These improvements led to an accurate determination of real municipal wastewater samples.

7q-and loss of a polymorphism for the met oncogene in a patient with myelofibrosis.

The met oncogene is the normal counterpart of a chemically-induced transforming gene. The chromosomal localization of met is 7q21-31. In a patient with myelofibrosis and an interstitial deletion on 7q, we demonstrate that a Taq I polymorphism for the met oncogene is lost in the neoplastic cells, thus indicating that the deletion occuring in the long arm of chromosome 7 involves the met locus.