Protective effects of non-catalytic proteins on endoglucanase activity at air and lignin interfaces.

The manner in which added non-catalytic proteins during enzymatic hydrolysis of lignocellulosic substrates enhances hydrolysis mechanisms is not completely understood. Prior research has indicated that a reduction in the non-specific adsorption of enzymes on lignin, and deactivation of enzymes exposed to air-liquid interface provide rationale. This work investigated root causes including effects of the air-liquid interface on non-catalytic proteins, and effects of lignin on endoglucanase. Three different experimental designs and three variables (air-liquid interfacial area, the types of lignin (acid or enzymatic lignin), and the presence of non-enzymatic protein (bovine serum albumin [BSA] or soy proteins ) were used. The results showed that acid isolated lignin adsorbed almost all endoglucanase activity initially present in supernatant, independent of air interface conditions (25 or 250 ml flasks) with the presence of BSA preventing this effect. Endoglucanase lost 30%-50% of its activity due to an air-liquid interface in the presence of lignin while addition of non-enzymatic protein helped to preserve this enzyme's activity. Langmuir and Freundlich models applied to experimental data indicated that the adsorption increases with increasing temperature for both endoglucanase and BSA. Adsorption of the enzyme and protein were endothermic with an increase in entropy. These results, combined, show that hydrophobicity plays a strong role in the adsorption of both endoglucanase and BSA on lignin.

Experimental optimization and techno-economic analysis of bioethanol production by simultaneous saccharification and fermentation process using sugarcane straw.

The present work aims to determine a suitable yield-productivity balance in bioethanol production from hydrothermally pretreated sugarcane straw via pre-saccharification (PS) and simultaneous saccharification and fermentation (SSF). PS experiments were carried out evaluating effects of enzymatic dosage, biomass loading, and PS time. The performance of the whole process (PSSSF) was evaluated based on overall ethanol yield and productivity considering a simultaneous optimization (desirability function) of both variables. The multi-criteria optimization enabled to reach 5.7% w/w ethanol concentration yielding 290 L of ethanol per ton of pretreated sugarcane straw within 45 h of total processing time. Furthermore, a techno-economic analysis was performed under optimized conditions (14.5 FPU/gcellulose, 19.3% w/v biomass loading and 33 h PS time). This process was integrated into a first-generation plant. Although the economic evaluation exhibited a negative performance, a sensitivity analysis indicated that a decrease of 23.3% in operational expenditure would be enough to achieve feasibility.

Photodynamic therapy for cutaneous hemangiosarcoma in dogs.

Cutaneous hemangiosarcoma is a malignant neoplasia that frequently occurs in dogs. The most effective treatment requires wide surgical excision of the tumor. To avoid mutilating surgeries, photodynamic therapy (PDT) could serve as an alternative treatment. This study aimed to treat cutaneous hemangiosarcomas in dogs using PDT with aluminium-chloride-phthalocyanine nanoemulsion (AlClPc-nano) as photosensitizer. Eight dogs with histopathological diagnosis of naturally occurring cutaneous hemangiosarcoma were treated. Animals were given intra and peritumoral injections of AlClPc-nano (13.3 µM). After 15 min, the masses were LED irradiated at a wavelength of 658-662 nm (80 mW potency) for 25 min (120 J/cm2 fluency). The number of sessions was based on lesion observations, with PDT sessions repeated every 7 days until the mass was no longer macroscopically visible. On that occasion, an excisional biopsy of the area was taken for histopathology analysis. Blood was collected from each animal before each PDT session and excisional biopsy for hematological analysis (blood counts; liver and kidney function). The number of PDT sessions varied from 2 to 4, depending on the size of the initial mass. Seven of the eight cases demonstrated complete remission of neoplasia. Microscopic analysis of the excisional biopsies showed necrosis and hemorrhage only, with no cancer cells, except in one case. During the treatment, inflammation and necrosis were macroscopically observed in the treated areas. The dogs did not show any alteration in blood parameters that could be related to the PDT. In conclusion, PDT with AlClPc-nano is a safe and effective treatment for cutaneous hemangiosarcoma in dogs.

Effect of severity factor on the hydrothermal pretreatment of sugarcane straw.

The recalcitrant structures of sugarcane straw and related lignocellulosic biomasses require a pretreatment step to enable a better enzymatic attack during the hydrolysis. Factors like the energy consumption and the formation of inhibitors require the optimization of the pretreatment step. Thus, the influence of different severity factors (SF) on hydrothermal (also called liquid hot water, LHW) pretreatment was evaluated using a factorial design 22 with central point. The obtained results showed that low values of SF (<3.39) did not promote reasonable alteration in the sugarcane straw structures, whereas high SF values (>4.70) resulted in loss of hydrolyzed sugars, generation of inhibitors such as furfural, and formation of pseudo-lignin structures, despite high hemicellulose removal (∼97%). The residence time exhibited low influence on LHW. An optimum condition was found for the process (10 min and 195 °C) with low cellulose solubilization (9.80%) and a reasonable hemicellulose removal (85.45%).

A kinetic model for hydrothermal pretreatment of sugarcane straw.

This work presents kinetic models of cellulose and hemicellulose extraction during hydrothermal pretreatment of sugarcane straw. Biomass was treated under conditions of 180, 195, and 210°C, using a solid/liquid ratio of 1:10 (w/v). In this study, cellobiose, glucose, formic acid and hydroxymethylfurfural (from cellulosic fraction) and xylose, arabinose, acetic acid, glucuronic acid and furfural (from hemicellulosic fraction) were taken into account in the kinetic parameters determination. The global search algorithm Simulated Annealing was used to fit the models. At 195°C/15min, 85% of hemicellulose and 21% of cellulose removal was reached. For the confidence regions, it was observed that it can be broad, which is coherent with the fact that the parameters are highly correlated. Kinetic models proposed for both cellulosic and hemicellulosic fractions degradation fitted well to the experimental data.

Aluminum-chloride-phthalocyanine encapsulated in liposomes: activity against naturally occurring dog breast cancer cells.

Breast tumors represent the most common malignant tumors. Current treatments for humans and pets rely on tumor excision and adjuvant chemotherapy, which may affect both cancer cells and normal cells. Photodynamic therapy (PDT) is an approved treatment modality for a variety of cancers and was recently recommended as a first-line treatment for non-melanoma skin cancers for humans. The main purpose of the present study was to determine the efficacy of PDT using aluminum-chloride-phthalocyanine that is encapsulated in liposomes and LED as a light source to kill naturally occurring female dog breast cancer in vitro. The cytotoxicity behavior of the encapsulated photosensitizer in the dark and under irradiation using the 670 nm laser were investigated using classical trypan blue and MTT cell viability tests, acridine orange and ethidium bromide staining to label organelles, and cell morphology. Cell morphology was evaluated using light and electron microscopy. Our results demonstrate a reduced cell viability that is associated with morphologic alterations. The neoplasic cell destruction was predominantly mediated via a necrotic process, which was assayed using acridine orange and ethidium bromide staining. These findings were confirmed using light and electronic microscopy. The photosensitizer or laser irradiation alone did not induce cytotoxicity or morphological alterations, indicating the safety and efficacy of PDT with chloro-aluminum-phthalocyanine that was encapsulated in liposomes for the treatment of breast cancer cells in vitro.

Noninvasive brain stimulation with high-frequency and low-intensity repetitive transcranial magnetic stimulation treatment for posttraumatic stress disorder.

OBJECTIVE: We aimed to investigate the efficacy of 20 Hz repetitive transcranial magnetic stimulation (rTMS) of either right or left dorsolateral prefrontal cortex (DLPFC) as compared to sham rTMS for the relief of posttraumatic stress disorder (PTSD)-associated symptoms. METHOD: In this double-blind, placebo-controlled phase II trial conducted between October 2005 and July 2008, 30 patients with DSM-IV-diagnosed PTSD were randomly assigned to receive 1 of the following treatments: active 20 Hz rTMS of the right DLPFC, active 20 Hz rTMS of the left DLPFC, or sham rTMS. Treatments were administered in 10 daily sessions over 2 weeks. A blinded rater assessed severity of core PTSD symptoms, depression, and anxiety before, during, and after completion of the treatment protocol. In addition, a battery of neuropsychological tests was measured before and after treatment. RESULTS: Results show that both active conditions-20 Hz rTMS of left and right DLPFC-induced a significant decrease in PTSD symptoms as indexed by the PTSD Checklist and Treatment Outcome PTSD Scale; however, right rTMS induced a larger effect as compared to left rTMS. In addition, there was a significant improvement of mood after left rTMS and a significant reduction of anxiety following right rTMS. Improvements in PTSD symptoms were long lasting; effects were still significant at the 3-month follow-up. Finally, neuropsychological evaluation showed that active 20 Hz rTMS is not associated with cognitive worsening and is safe for use in patients with PTSD. CONCLUSIONS: These results support the notion that modulation of prefrontal cortex can alleviate the core symptoms of PTSD and suggest that high-frequency rTMS of right DLPFC might be the optimal treatment strategy.

Long-term evaluation of a new ventriculoperitoneal shunt valve system in a dog.

OBJECTIVE: To report on the use of a new ventriculoperitoneal shunt (VPS) valve system utilized in a dog with hydrocephalus and to describe the clinical course over 20 months after implantation. CASE SUMMARY: A 3-month-old female Lhasa Apso dog was presented with lateral strabismus, domed calvarium, and visual deficits. A lateral skull radiograph revealed a persistent fontanelle. Transfontanellar ultrasonographic examination and computed tomographic examination showed excessive accumulation of fluid within the ventricles. The owner had observed symptoms as early as 1 month after birth, suggesting congenital hydrocephalus. A VPS with a new valve system that inhibits cerebrospinal fluid overdrainage and obstruction of the catheter was implanted. The dog showed clinical improvement 48 hours after the procedure. Twenty days after shunt implantation, another computed tomography scan was performed that showed reduction in ventricle size. The evaluation of VPS patency was carried out 20 months after surgery and demonstrated that the system was working properly without obstruction. NEW OR UNIQUE INFORMATION PROVIDED: There are reports in the literature describing the use of several devices to perform VPS in dogs. A new device not previously described in the veterinary literature was used in this case report, and according to the manufacturer's description, this device inhibits proteinaceous build-up, which is usually responsible for subsequent catheter obstructions.

Reproductive ecology of five sympatric Agave Littaea (Agavaceae) species in central Mexico.

We studied a community of Agave species that coexist in the Metztitlán Canyon in Central Mexico. During 2001, 2002, and 2003, we analyzed floral traits and rosette allometry in five species belonging to the subgenus Littaea: A. celsii albicans, A. xylonacantha, A. difformis, A. striata, and Agave sp.; and observed floral visitors for each species. We report the first evidence of bat visitation in the subgenus Littaea and find that bats (Leptonycteris curasoae, Choeronycteris mexicana, and Glossophaga sp.) are the primary pollinators in four species. Honeybees, hummingbirds, bumblebees and hawkmoths were also common visitors. We propose that the presence of diurnal pollinators may increase the reproductive success of the plant when offering pollinator services additional to the coadapted pollinator. We also found evidence of selection pressures toward semelparity because pollinators are selecting for taller inflorescences in three of the five species. There is phenological complementarity in this community because the flowering periods of the five species span the entire year, although there are some periods when pairs of species overlap. Additionally, we found evidence for character displacement in rosette sizes and separation of spatial and temporal resource use in pollinator composition among species.

Ecología evolutiva de escherichia coli / Evolutive ecology of escherichia coli

Escherichia coli es el organismo mejor conocido en términos de su genética y fisiología. Sin embargo, se sabe poco de su ecología y biología evolutiva. En este trabajo revisamos aspectos de su biología, genómica, ecología genética de poblaciones. Estudios clásicos, basados principalmente en cepas aisladas de humanos, sugerían que E.coli es una especie con una fuerte estructura clonal, con poca o ninguna recombinación. Nosotros hemos ensamblado y analizado una colección llamada IECOL, con más de 2000 cepas provenientes de animales de varios lugares del mundo, de humanos de México y de cepas silvestres de diferentes ambientes. En este trabajo se presentan datos sobre genética de poblaciones y evolución molecular de E.coli obtenidos a partir de esta colección. Estos, junto con otros datos de la literatura reciente, indican que E.coli es un organismo muy diverso, con un genoma extraordinariamente dinámico donde la recobinación es importante, y que las combinaciones exitosas pueden dispersarse de manera epidémica en las poblaciones humanas o animales, dando una falsa señal de clonalidad. Finalmente, se ilustra el potencial de uso de la colección (IECOL) en estudios que estamos realizando sobre la evolución de tasas de mutación, y sobre la evolución de genes patogénicos en la especie

Condiciones teórico-metodológicas para la realización de un diagnóstico territorial de salud mental en Santa Fe de Bogotá / Theoretical-methodological conditions for the realization of a territorial mental health diagnosis in Santa Fe de Bogota

Introducción Este trabajo se basa en la experiencia piloto de salud mental que se realiza enTunjuelito (Centro de Salud Mental Comunitaria San Benito) y pretende determinar las condiciones teórico-metodológicas para un diagnóstico de salud mental en Santa Fe de Bogotá. Objetivo Establecer una metodología para describir el estado de salud mental y explorar las variables asociadas a los indicadores propuestos mediante estrategias cuantitativas y cualitativas. Metodología Mediante el trabajo interdisciplinario de expertos se obtuvieron tanto las definiciones teórico-metodológicas como los resultados finales. La estrategia metodológica general para la obtención de instrumentos cuantitativos y cualitativos tuvo los siguientes procesos: 1. acuerdo y definición de constructos teóricos: 2. definición de variables e indicadores: 3. elaboración de instrumentos experimentales; 4- consulta con grupo de clínicos y equipo: 5. aplicación piloto, y 6. calibración (modelo de Rash para la cuantitativa) y ajuste. El diseño muestral se plantea como una propuesta costo-efectiva considerando grupos de localidades. Resultados El producto final es un análisis del marco teórico, el diseño de la muestra por grupos de localidades que conforman regionales en Bogotá y una metodología que combina técnicas cualitativas y cuantitativas. Conclusiones La construcción interdisciplinaria empleando diferentes metodologías mejora la posibilidad de recoger información fiable sobre condiciones de salud mental. La definición de salud mental debe incluir aspectos positivos y no sólo prevalencia de enfermedades. El diseño muestral por grupos de localidades para estudios de prevalencia aporta al proceso de regionalización del sector salud.

Introduction This work is based on the mental health pilot experience carried out inTunjuelito (San Benito Community Mental Health Center) and aims to determine the theoretical and methodological conditions for a mental health diagnosis in Santa Fe de Bogotá. Objective To establish a methodology to describe the state of mental health and explore the variables associated with the proposed indicators through quantitative and qualitative strategies. Methodology Through the interdisciplinary work of experts, both the theoretical-methodological definitions and the final results were obtained. The general methodological strategy for obtaining quantitative and qualitative instruments had the following processes: 1. agreement and definition of theoretical constructs: 2. definition of variables and indicators: 3. elaboration of experimental instruments; 4- consultation with the group of clinicians and team: 5. pilot application, and 6. calibration (Rash model for the quantitative) and adjustment. The sample design is proposed as a cost-effective proposal considering groups of localities. Results The final product is an analysis of the theoretical framework, the sample design by groups of localities that make up the Bogota region, and a methodology that combines qualitative and quantitative techniques. Conclusions The interdisciplinary construction using different methodologies improves the possibility of collecting reliable information on mental health conditions. The definition of mental health should include positive aspects and not only prevalence of diseases. The sample design by groups of localities for prevalence studies contributes to the regionalization process of the health sector.