Mechanistic Insights into the Light-Driven Catalysis of an Immobilized Lipase on Plasmonic Nanomaterials

The use of light as an external stimulus to control the enzyme activity is an emerging strategy that enables accurate, remote, and noninvasive biotransformations. In this context, immobilization of enzymes on plasmonic nanoparticles offers an opportunity to create light-responsive biocatalytic materials. Nevertheless, a fundamental and mechanistic understanding of the effects of localized surface plasmon resonance (LSPR) excitation on enzyme regulation remains elusive. We herein investigate the plasmonic effects on biocatalysis using Au nanospheres (AuNSp) and nanostars (AuNSt) as model plasmonic nanoparticles, lipase from Candida antarctica fraction B (CALB) as a proof-of-concept enzyme, and 808 nm as near-infrared light excitation. Our data show that LSPR excitation enables an enhancement of 58% in the enzyme activity for CALB adsorbed on AuNSt, compared with the dark conditions. This work shows how photothermal heating over the LSPR excitation enhances the CALB activity through favoring product release in the last step of the enzyme mechanism. We propose that the results reported herein shed important mechanistic and kinetic insights into the field of plasmonic biocatalysis and may inspire the rational development of plasmonic nanomaterial-enzyme hybrids with tailored activities under external light irradiation.Peer reviewe

Plant phenotyping and phenomics for plant breeding

A major challenge for food production in the coming decades is to meet the food demands of a growing population (Beddington, 2010). The difficulty of expanding agricultural land, along with the effect of climate change and the increase in world population are the current societal changes that make necessary to accelerate research to improve yield-potential and adaptation to stressful environments (Lobos et al., 2014; Camargo and Lobos). [...

First GPS Baseline Results from the North Andes

The CASA UNO GPS (Global Positioning System) experiment (January-February 1988) has provided the first epoch baseline measurements for the study of plate motions and crustal deformation in and around the North Andes. Two dimensional horizontal baseline repeatabilities are as good as 5 parts in 108 for short baselines (100-1000km), and better than3 parts in 108 for long baselines (\u3e1000km). Vertical repeatabilities are typically 4 -6 cm, with a weak dependence on baseline length. The expected rate of plate convergence across the Colombia Trench is 6-8 cm/yr, which should be detectable by the repeat experiment planned for 1991. Expected deformation rates within the North Andes are of the order of 1 cm/yr, which may be detectable with the 1991 experiment

Synthetic Peptides Mimic gp75 from Paracoccidioides brasiliensis in the Diagnosis of Paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease, endemic in Latin America, caused by the thermal dimorphic fungus Paracoccidioides brasiliensis. Although some fungal antigens have already been characterized and used for serological diagnosis, cross-reactions have been frequently observed. Thus, the examination of fungal forms in clinical specimens or isolation of P. brasiliensis by culture is still the most frequent method for the diagnosis of this mycosis. In this study, a random peptide phage display library was used to select mimotopes of P. brasiliensis, which were employed as antigens in an indirect enzyme-linked immunosorbent assay. The protective monoclonal antibody against experimental PCM (anti-gp75) was used as molecular target to screen a phage display library. That approach led to a synthetic peptide named P2, which was synthesized and tested against PCM patients’ sera to check whether it was recognized. There was significant recognition of P2 by sera of untreated PCM patients when compared with normal human sera. Sera from treated PCM group, patients with other mycosis or co-infected with HIV had much lower recognition of P2 than untreated patient group. The test showed a sensitivity of 100 and 94.59% of specificity in relation to human sera control. These data indicate a potential use of P2 as diagnostic tool in PCM. Its application for serological diagnosis of PCM may contribute to the development and standardization of simpler, faster and highly reproducible immunodiagnostic tests at low cost

Prevalence of vancomycin-resistant Enterococcus fecal colonization among kidney transplant patients

BACKGROUND: End stage renal disease patients are at risk of Vancomycin-Resistant Enterococcus (VRE) infections. The first reports of VRE isolation were from hemodialysis patients. However, to date, VRE fecal colonization rates as well as associated risk factors in kidney transplant patients have not yet been established in prospective studies. METHODS: We collected one or two stool samples from 280 kidney transplant patients and analysed the prevalence of VRE and its associated risk factors. Patients were evaluated according to the post-transplant period: group 1, less than 30 days after transplantation (102 patients), group 2, one to 6 months after transplantation (73 patients) and group 3, more than 6 months after transplantation (105 patients). RESULTS: The overall prevalence rate of fecal VRE colonization was 13.6% (38/280), respectively 13.7% for Group 1, 15.1% for group 2 and 12.4% for group 3. E. faecium and E. faecalis comprised 50% of all VRE isolates. No immunologic variables were clearly correlated with VRE colonization and no infections related to VRE colonization were reported. CONCLUSION: Fecal VRE colonization rates in kidney transplant patients were as high as those reported for other high-risk groups, such as critical care and hemodialysis patients. This high rate of VRE colonization observed in kidney transplant recipients may have clinical relevance in infectious complications

Lactancia materna ineficaz: prevalencia y factores asociados

RESUMENIntroducción: Es posible evitar muertes neonatales mediante la lactancia materna desde el primer día devida, pues la leche materna es el alimento óptimo para el lactante por su contenido nutricional necesariofavorecer el crecimiento y desarrollo. Objetivo: Determinar la prevalencia y factores asociados aldiagnóstico de enfermería “Lactancia materna ineficaz” en lactantes menores de 6 meses hospitalizados enuna institución de tercer nivel.Metodología: Estudio de corte transversal. Se seleccionaron 108 binomios(madre e hijo) hospitalizados en una institución de tercer nivel de atención en el año 2009, se aplicó unformato validado para identificar el diagnóstico. Se realizó análisis Rasch a las variables que representanlas características definitorias del diagnóstico, con el cual se creó una escala de 0 a 100 y se construyóun modelo de regresión lineal con las variables asociadas a la medida del diagnóstico.Resultados:la prevalencia del diagnóstico fue de 93,5 %, la característica definitoria más fácil de encontrar fueIncapacidad del lactante para agarrarse al pecho materno y la más difícil fue agitación y llanto del lactantedentro de la primera hora después de la lactancia materna. La regresión lineal mostró factores asociadoscomo: género femenino, peso del lactante y necesidad de la madre de ir a orinar.Conclusiones: Existeuna tendencia desfavorable tanto en la prevalencia como en la duración de la lactancia materna para loslactantes hospitalizados; la promoción de la lactancia materna debe ser un trabajo interdisciplinario;modificar las normas hospitalarias favoreciendo el contacto del binomio y la puesta temprana al pechomaterno. Salud UIS 2011; 43 (3): 271-279Palabras clave: Lactancia materna, diagnóstico de enfermería, lactante, prevalencia,factores asociadosABSTRACTIntroduction: neonatal deaths can be prevented by breastfeeding from the first day of life, as is the optimal foodfor infants by their nutritional content required for better growth and development.Objective: To determine theprevalence and associated factors with nursing diagnosis “ineffective breastfeeding” in infants under than 6 monthshospitalized in a tertiary institution.Methodology: Cross sectional study. We selected 108 pairs (mother and child)hospitalized in an institution of tertiary care in 2009, we applied a validated format to identify the diagnosis. Raschanalysis was performed for variables that represent the defining characteristics of the diagnosis, which created ascale of 0 to 100 and built a linear regression model the variables associated with the extent of diagnosis.Results:Prevalence of diagnosis was 93,5 %, the defining characteristic was easier to find the infant’s inability to hold onto the breast and the hardest was shaking and crying of the infant within the first hour after breastfeeding. Linearregression was associated factors such as: female gender, weight infant and the mother need to urinate.Conclusions:There is an unfavorable trend in both the prevalence and duration of breastfeeding for infants hospitalized, promotionof breastfeeding should be an interdisciplinary, modify hospital policies favoring the contact of the binomial and theearly start to the chest maternal. Salud UIS 2011; 43 (3): 271-279Keywords: Breastfeeding, nursing diagnosis, infant, prevalence, associated factor

Lactancia materna ineficaz: prevalencia y factores asociados

RESUMENIntroducción: Es posible evitar muertes neonatales mediante la lactancia materna desde el primer día devida, pues la leche materna es el alimento óptimo para el lactante por su contenido nutricional necesariofavorecer el crecimiento y desarrollo. Objetivo: Determinar la prevalencia y factores asociados aldiagnóstico de enfermería “Lactancia materna ineficaz” en lactantes menores de 6 meses hospitalizados enuna institución de tercer nivel.Metodología: Estudio de corte transversal. Se seleccionaron 108 binomios(madre e hijo) hospitalizados en una institución de tercer nivel de atención en el año 2009, se aplicó unformato validado para identificar el diagnóstico. Se realizó análisis Rasch a las variables que representanlas características definitorias del diagnóstico, con el cual se creó una escala de 0 a 100 y se construyóun modelo de regresión lineal con las variables asociadas a la medida del diagnóstico.Resultados:la prevalencia del diagnóstico fue de 93,5 %, la característica definitoria más fácil de encontrar fueIncapacidad del lactante para agarrarse al pecho materno y la más difícil fue agitación y llanto del lactantedentro de la primera hora después de la lactancia materna. La regresión lineal mostró factores asociadoscomo: género femenino, peso del lactante y necesidad de la madre de ir a orinar.Conclusiones: Existeuna tendencia desfavorable tanto en la prevalencia como en la duración de la lactancia materna para loslactantes hospitalizados; la promoción de la lactancia materna debe ser un trabajo interdisciplinario;modificar las normas hospitalarias favoreciendo el contacto del binomio y la puesta temprana al pechomaterno. Salud UIS 2011; 43 (3): 271-279Palabras clave: Lactancia materna, diagnóstico de enfermería, lactante, prevalencia,factores asociadosABSTRACTIntroduction: neonatal deaths can be prevented by breastfeeding from the first day of life, as is the optimal foodfor infants by their nutritional content required for better growth and development.Objective: To determine theprevalence and associated factors with nursing diagnosis “ineffective breastfeeding” in infants under than 6 monthshospitalized in a tertiary institution.Methodology: Cross sectional study. We selected 108 pairs (mother and child)hospitalized in an institution of tertiary care in 2009, we applied a validated format to identify the diagnosis. Raschanalysis was performed for variables that represent the defining characteristics of the diagnosis, which created ascale of 0 to 100 and built a linear regression model the variables associated with the extent of diagnosis.Results:Prevalence of diagnosis was 93,5 %, the defining characteristic was easier to find the infant’s inability to hold onto the breast and the hardest was shaking and crying of the infant within the first hour after breastfeeding. Linearregression was associated factors such as: female gender, weight infant and the mother need to urinate.Conclusions:There is an unfavorable trend in both the prevalence and duration of breastfeeding for infants hospitalized, promotionof breastfeeding should be an interdisciplinary, modify hospital policies favoring the contact of the binomial and theearly start to the chest maternal. Salud UIS 2011; 43 (3): 271-279Keywords: Breastfeeding, nursing diagnosis, infant, prevalence, associated factor

Ca. Nitrososphaera and Bradyrhizobium are inversely correlated and related to agricultural practices in long-term field experiments

Agricultural land management, such as fertilization, liming, and tillage affects soil properties, including pH, organic matter content, nitrification rates, and the microbial community. Three different study sites were used to identify microorganisms that correlate with agricultural land use and to determine which factors regulate the relative abundance of the microbial signatures of the agricultural land-use. The three sites included in this study are the Broadbalk Experiment at Rothamsted Research, UK, the Everglades Agricultural Area, Florida, USA, and the Kellogg Biological Station, Michigan, USA. The effects of agricultural management on the abundance and diversity of bacteria and archaea were determined using high throughput, barcoded 16S rRNA sequencing. In addition, the relative abundance of these organisms was correlated with soil features. Two groups of microorganisms involved in nitrogen cycle were highly correlated with land use at all three sites. The ammonia oxidizing-archaea, dominated by Ca. Nitrososphaera, were positively correlated with agriculture while a ubiquitous group of soil bacteria closely related to the diazotrophic symbiont, Bradyrhizobium, was negatively correlated with agricultural management. Analysis of successional plots showed that the abundance of ammonia oxidizing-archaea declined and the abundance of bradyrhizobia increased with time away from agriculture. This observation suggests that the effect of agriculture on the relative abundance of these genera is reversible. Soil pH and NH(3) concentrations were positively correlated with archaeal abundance but negatively correlated with the abundance of Bradyrhizobium. The high correlations of Ca. Nitrososphaera and Bradyrhizobium abundances with agricultural management at three long-term experiments with different edaphoclimatic conditions allowed us to suggest these two genera as signature microorganisms for agricultural land use