Gender effect of glucose, insulin/glucagon ratio, lipids, and nitrogen-metabolites on serum HGF and EGF levels in patients with diabetes type 2.

Hepatocyte growth factor (HGF) exhibits potent growth-inducing properties across various tissues, while epidermal growth factor (EGF) acts as a molecular integration point for diverse stimuli. HGF plays a crucial role in hepatic metabolism, tissue repair, and offers protective effects on epithelial and non-epithelial organs, in addition to its involvement in reducing apoptosis and inflammation, underscoring its anti-inflammatory capabilities. The HGF-Met system is instrumental in hepatic metabolism and enhancing insulin sensitivity in animal diabetes models. Similarly, the EGF and its receptor tyrosine kinase family (EGFR) are critical in regulating cell growth, proliferation, migration, and differentiation in both healthy and diseased states, with EGF also contributing to insulin sensitivity. In this observational study, we aimed to identify correlations between serum levels of HGF and EGF, insulin, glucagon, glucose, and primary serum lipids in patients with type 2 diabetes mellitus (DM), taking into account the impact of gender. We noted differences in the management of glucose, insulin, and glucagon between healthy men and women, potentially due to the distinct influences of sexual hormones on the development of type 2 DM. Additionally, metabolites such as glucose, albumin, direct bilirubin, nitrites, and ammonia might influence serum levels of growth factors and hormones. In summary, our results highlight the regulatory role of insulin and glucagon in serum glucose and lipids, along with variations in HGF and EGF levels, which are affected by gender. This link is especially significant in DM, where impaired cell proliferation or repair mechanisms lead to metabolic changes. The gender-based differences in growth factors point to their involvement in the pathophysiology of the disease.

Acute lichenoid and varioliform pityriasis in a pediatric patient.

BACKGROUND: Pityriasis lichenoides et varioliformis acuta (PLEVA) is a rare dermatosis recognized as a benign condition of unknown etiopathogenesis. It is more common in pediatric patients and young adults and is characterized by multiple small or large erythematous plaques spread over the trunk and extremities. CASE REPORT: We describe the case of a 5-year-old male, previously healthy, with multiple erythematous lesions that disappeared leaving hypopigmented macules. The biopsy reported histological changes suggestive of mycosis fungoides. After a second revision of lamellae in this hospital, lymphocytic vasculitis (LV) with focal epidermal necrosis consistent with acute pityriasis lichenoides (PL) was identified. CONCLUSIONS: The existing knowledge about PLEVA lacks a consensus in specifying its classification, etiopathogenesis, diagnosis, and treatment, so this clinical condition represents a medical challenge. The diagnosis is made by clinical suspicion and confirmed by histology. The objective of this article was to report a case of PLEVA with an atypical presentation due to its histopathological findings, being the first report showing LV in children, as well as a review of the literature.

INTRODUCCIÓN: La pitiriasis liquenoide y varioliforme aguda (PLEVA) es una dermatosis poco frecuente, de etiopatogenia desconocida y evolución autolimitada. Es más común en pacientes pediátricos y adultos jóvenes, y está caracterizada por la presencia de múltiples placas eritematoescamosas pequeñas o grandes, diseminadas en el tronco y las extremidades. CASO CLÍNICO: Se describe el caso de un escolar de 5 años, de sexo masculino, previamente sano, que presentó múltiples cuadros de lesiones eritematosas que desaparecían dejando máculas hipopigmentadas. La biopsia reportó cambios histológicos sugestivos de micosis fungoide. Se realizó una segunda revisión de laminillas, identificando vasculitis linfocítica con necrosis epidérmica focal, consistente con pitiriasis liquenoide aguda. CONCLUSIONES: El conocimiento acerca de la PLEVA carece de un consenso que especifique su clasificación, etiopatogenia, diagnóstico y tratamiento, por lo que esta condición clínica representa un desafío médico. El diagnóstico se realiza por sospecha clínica y se confirma por histología. El objetivo de este artículo fue reportar un caso de PLEVA con presentación atípica por los hallazgos histopatológicos, siendo este el primer reporte de vasculitis linfocítica en niños, y además se realiza una revisión de la literatura.

Acute lichenoid and varioliform pityriasis in a pediatric patient / Vasculitis linfocítica en pitiriasis liquenoide y varioliforme aguda de un paciente pediátrico

Abstract Background: Pityriasis lichenoides et varioliformis acuta (PLEVA) is a rare dermatosis recognized as a benign condition of unknown etiopathogenesis. It is more common in pediatric patients and young adults and is characterized by multiple small or large erythematous plaques spread over the trunk and extremities. Case report: We describe the case of a 5-year-old male, previously healthy, with multiple erythematous lesions that disappeared leaving hypopigmented macules. The biopsy reported histological changes suggestive of mycosis fungoides. After a second revision of lamellae in this hospital, lymphocytic vasculitis (LV) with focal epidermal necrosis consistent with acute pityriasis lichenoides (PL) was identified. Conclusions: The existing knowledge about PLEVA lacks a consensus in specifying its classification, etiopathogenesis, diagnosis, and treatment, so this clinical condition represents a medical challenge. The diagnosis is made by clinical suspicion and confirmed by histology. The objective of this article was to report a case of PLEVA with an atypical presentation due to its histopathological findings, being the first report showing LV in children, as well as a review of the literature.

Resumen Introducción: La pitiriasis liquenoide y varioliforme aguda (PLEVA) es una dermatosis poco frecuente, de etiopatogenia desconocida y evolución autolimitada. Es más común en pacientes pediátricos y adultos jóvenes, y está caracterizada por la presencia de múltiples placas eritematoescamosas pequeñas o grandes, diseminadas en el tronco y las extremidades. Caso clínico: Se describe el caso de un escolar de 5 años, de sexo masculino, previamente sano, que presentó múltiples cuadros de lesiones eritematosas que desaparecían dejando máculas hipopigmentadas. La biopsia reportó cambios histológicos sugestivos de micosis fungoide. Se realizó una segunda revisión de laminillas, identificando vasculitis linfocítica con necrosis epidérmica focal, consistente con pitiriasis liquenoide aguda. Conclusiones: El conocimiento acerca de la PLEVA carece de un consenso que especifique su clasificación, etiopatogenia, diagnóstico y tratamiento, por lo que esta condición clínica representa un desafío médico. El diagnóstico se realiza por sospecha clínica y se confirma por histología. El objetivo de este artículo fue reportar un caso de PLEVA con presentación atípica por los hallazgos histopatológicos, siendo este el primer reporte de vasculitis linfocítica en niños, y además se realiza una revisión de la literatura.

Intervention strategies with 2D cellular automata for testing SARS-CoV-2 and reopening the economy.

During the period of time between a new disease outbreaks and its vaccine is deployed, the health and the economic systems have to find a testing strategy for reopening activities. In particular, asymptomatic individuals, who transmit locally the COVID-19 indoors, have to be identified and isolated. We proposed a 2D cellular automaton based on the SI epidemic model for selecting the most desirable testing frequency and identifying the best fitting size of random trails on local urban environments to diagnose SARS-CoV-2 and isolate infected people. We used the complex systems approach to face the challenge of a large-scale test strategy based on urban interventions, starting with first responders and essential workers. We used the case of Mexico to exemplify a credible and intelligent intervention that reduces the virus transmission and detects economic and health costs. Findings suggest that controlling and stopping the virus transmission in a short period of time are possible if the frequency of testing is daily and the percentage of random samples to be tested is at least 90%. This combination of model parameters represents the least expensive intervention compared to others. Therefore, the key for a national testing-isolating strategy is local interventions.

Effect of sericin, a silk derived protein, on the amplification of Zika virus in insect and mammalian cell cultures.

Sericin, a silk-derived non-immunogenic protein, has been used to improve cell culture performance by increasing viability, cell concentration, and promoting adherence of several cell lines. Here, we hypothesized that the properties of sericin can enhance the amplification of flaviviruses in cell cultures. The propagation of flavivirus is inefficient and limits scientific research. Zika virus (ZIKV) is an important human pathogen that has been widely studied because of its high impact on public health. There is a need to amplify Zika virus both for research and vaccine development. In this work, we show that sericin improves ZIKV amplification in insect (C6/36) and mammalian (Vero) cell cultures, and that it has a cryoprotectant capacity. Supplementation of cell culture media with sericin at 80 µg/mL resulted in a significant increase of 1 log in the concentration of ZIKV infectious particles produced from both cell lines. Furthermore, final virus yields increased between 5 and 10-fold in Vero cells and between 7 and 23-fold in C6/36 cells when sericin was supplemented, compared to control conditions. These results show that sericin is an effective supplement to increase ZIKV production by Vero and C6/36 cells. Additionally, sericin was a suitable cryoprotective agent, and hence an alternative to FBS and DMSO, for the cryopreservation of C6/36 cells but not for Vero cells.

Home Learning Environments of Children in Mexico in Relation to Socioeconomic Status.

We explored the home learning environments of 173 Mexican preschool children (aged 3-6 years) in relation to their numeracy performance. Parents indicated the frequency of their formal home numeracy and literacy activities, and their academic expectations for children's numeracy and literacy performance. Children completed measures of early numeracy skills. Mexican parent-child dyads from families with either high- or low-socioeconomic status (SES) participated. Low-SES parents (n = 99) reported higher numeracy expectations than high-SES parents (n = 74), but similar frequency of home numeracy activities. In contrast, high-SES parents reported higher frequency of literacy activities. Path analyses showed that operational (i.e., advanced) numeracy activities were positively related to children's numeracy skills in the high- but not in the low-SES group. These findings improve the understanding of the role of the home environment in different contexts and provide some insights into the sources of the variable patterns of relations between home learning activities and children's numeracy outcomes. They also suggest that SES is a critical factor to consider in research on children's home numeracy experiences.

Horseback riding pathways and harbors at the beginning of the colonial era in Mexico.

The introduction of horses in the New World changed the way of traveling on complex terrains. This change reconfigured the land transport network connecting harbors in the region. However, data of horseback riding pathways among harbors is scarce. We analyzed the case of Mexico at the beginning of the colonial period to recreate routes that connected ancient harbors and to identify the network characteristics of a large-scale system of routes. We used the complex systems approach as a framework in which we applied the least cost path analysis to reconstruct a network of horseback paths, and we computed the node betweenness centrality to identify the most probable locations that controlled de flow of travels. Findings suggest that horses modified the transportation system by expanding the connections and increasing the speed of traveling across the New Spain territory. The node betweenness centrality suggests that some locations organized the flow of traveling based on a few harbors located at the central region. Therefore, the horse allowed the Spaniards to reshape the spatial organization in the colonial era in Mexico.

Dynamic Modeling of CHO Cell Metabolism Using the Hybrid Cybernetic Approach With a Novel Elementary Mode Analysis Strategy.

Chinese hamster ovary (CHO) cell culture has a major importance on the production of biopharmaceuticals, including recombinant therapeutic proteins such as monoclonal antibodies (MAb). Mathematical modeling of biological systems can successfully assess metabolism complexity while providing logical and systematic methods for relevant genetic target and culture parameter identification toward cell growth and productivity improvements. Most modeling approaches on CHO cells have been performed under stationary constraints, and only a few dynamic models have been presented on simplified reaction sets, due to substantial overparameterization problems. The hybrid cybernetic modeling (HCM) approach has been recently used to describe the dynamic behavior by incorporating regulation between different metabolic states by elementary mode participation control, with sets of equations evaluated by objective functions. However, as metabolic networks evaluated are constructed toward a genomic scale, and cell compartmentalization is considered, identification of the active set becomes more difficult as EM number exponentially grows. Thus, the development of robust approaches for EM active set selection and analysis with smaller computational requirements is required to impulse the use of cybernetic modeling on larger up to genome-scale networks. In this report, a novel elementary mode selection strategy, based on a polar representation of the convex solution space is presented and coupled to a cybernetic approach to model the dynamic physiologic and metabolic behavior of CHO-S cell cultures. The proposed Polar Space Yield Analysis (PSYA) was compared to other reported elementary mode selection approaches derived from Common Metabolic Objective Analysis (CMOA) used in Flux Balance Analysis (FBA), Yield Space Analysis (YSA), and Lumped Yield Space Analysis (LYSA). For this purpose, exponential growth phase dynamic metabolic models were calculated using kinetic rate equations based on previously modeled growth parameters. Finally, complete culture dynamic metabolic flux models were constructed using the HCM approach with selected elementary mode sets. The yield space elementary mode- and the polar space elementary mode- hybrid cybernetic models presented the best fits and performances. Also, a flux reaction perturbation prediction approach based on the polar yield solution space resulted useful for metabolic network flux distribution capability analysis and identification of potential genetic modifications targets.

Overexpression of the mitochondrial pyruvate carrier reduces lactate production and increases recombinant protein productivity in CHO cells.

Chinese hamster ovary (CHO) cells are characterized by a low glucose catabolic efficiency, resulting in undesirable lactate production. Here, it is hypothesized that such low efficiency is determined by the transport of pyruvate into the mitochondria. The mitochondrial pyruvate carrier (MPC), responsible for introducing pyruvate into the mitochondria, is formed by two subunits, MPC1 and MPC2. Stable CHO cell lines, overexpressing the genes of both subunits, were constructed to facilitate the entry of pyruvate into the mitochondria and its incorporation into oxidative pathways. Significant overexpression of both genes, compared to the basal level of the control cells, was verified, and subcellular localization of both subunits in the mitochondria was confirmed. Kinetic evaluation of the best MPC overexpressing CHO cells showed a reduction of up to 50% in the overall yield of lactate production with respect to the control. An increase in specific growth rate and maximum viable cell concentration, as well as an increase of up to 40% on the maximum concentration of two recombinant model proteins transiently expressed (alkaline phosphatase or a monoclonal antibody), was also observed. Hybrid cybernetic modeling, that considered 89 reactions, 25 extracellular metabolites, and a network of 62 intracellular metabolites, explained that the best MPC overexpression case resulted in an increased metabolic flux across the mitochondrial membrane, activated a more balanced growth, and reduced the Warburg effect without compromising glucose consumption rate and maximum cell concentration. Overall, this study showed that transport of pyruvate into the mitochondria limits the efficiency of glucose oxidation, which can be overcome by a cell engineering approach.

Nonlinearity and distance of ancient routes in the Aztec Empire.

This study explores the way in which traveling paths in ancient cultures are characterized by the relationship between nonlinear shapes and path lengths in terms of distances. In particular, we analyze the case of trade routes that connected Aztec settlements around 1521 CE in central Mexico. Based on the complex systems perspective, we used the least cost path approximation to reconstruct a hypothetical large-scale map of routes reproducing physical connections among ancient places. We compared these connections with different spatial configurations and identified the probability distribution functions of path lengths. We evaluated the nonlinearity using the mean absolute error based on the path fitness of simple linear models. We found asymmetrical distributions and positive relationships between those measures. If a path length increases, so does its nonlinearity. Thus, the simple pattern of traveling in the Aztec region is fairly unlikely to be straight and short. Complex pathways can represent most of the ancient routes in central Mexico.

The role of oxidant stress and gender in the erythrocyte arginine metabolism and ammonia management in patients with type 2 diabetes.

OBJECTIVES: To study the differences in the levels of nitrogen metabolites, such as ammonia and nitric oxide and the correlations existing among them in both red blood cells (RBCs) and serum, as well as the possible differences by gender in healthy subjects and patients with type 2 Diabetes Mellitus (DM). DESIGN AND METHODS: This cross-sectional study included 80 patients diagnosed with type 2 DM (40 female and 40 male patients) and their corresponding controls paired by gender (40 female and 40 male). We separated serum and RBC and determined metabolites mainly through colorimetric and spectrophotometric assays. We evaluated changes in the levels of the main catabolic by-products of blood nitrogen metabolism, nitric oxide (NO), and malondialdehyde (MDA). RESULTS: Healthy female and male controls showed a differential distribution of blood metabolites involved in NO metabolism and arginine metabolism for the ornithine and urea formation. Patients with DM had increased ammonia, citrulline, urea, uric acid, and ornithine, mainly in the RBCs, whereas the level of arginine was significantly lower in men with type 2 DM. These findings were associated with hyperglycemia, glycosylated hemoglobin (Hb A1C), and levels of RBC's MDA. Furthermore, most of the DM-induced alterations in nitrogen-related metabolites appear to be associated with a difference in the RBC capacity for the release of these metabolites, thereby causing an abrogation of the gender-related differential management of nitrogen metabolites in healthy subjects. CONCLUSIONS: We found evidence of a putative role of RBC as an extra-hepatic mechanism for controlling serum levels of nitrogen-related metabolites, which differs according to gender in healthy subjects. Type 2 DM promotes higher ammonia, citrulline, and MDA blood levels, which culminate in a loss of the differential management of nitrogen-related metabolites seen in healthy women and men.

Costo social del free-ride en cartagena - colombia: un análisis para el subsector de los establecimientos de lavado de vehículos

Los establecimientos de lavado de vehículos representan un problema ambiental, debido al uso intensivo del agua, en su funcionamiento. Además, los lavaderos, de la ciudad de Cartagena, tienden a actuar como free-riders, es decir, que en las 15 Unidades Comuneras de Gobierno Urbano, se encuentran lavaderos que evaden parte del pago por el uso de agua, lo que genera un costo, asumido por la sociedad y por las generaciones futuras. El presente artículo, se centra en determinar el costo social producido por el fenómeno del free-ride en los lavaderos de autos en Cartagena, para el periodo 2018, 2028 y 2038. Los resultados obtenidos muestran que el costo social proyectado, para estos lapsos, será de $1.351, $6.051 y $12.694 millones a precios corrientes, respectivamente.

The vehicle washing facilities represent an environmental problem, due to the intensive use of water as a productive input in their daily operations. Also, the car washes of the city of Cartagena tend to act as free riders, in others words, they evade the full payment for the used water, which generates a cost that is borne by society and future generations. This article focuses primarily on determining the social cost caused by the Free-Ride phenomenon on the car washes from Cartagena for 2018, 2028 and 2038. The results show that the social cost forecasted for those years will be $1.351, $6.051 and $12.694 million in current prices respectively.

The assembly conformation of rotavirus VP6 determines its protective efficacy against rotavirus challenge in mice.

Viral protein assemblies have shown to be superior immunogens used in commercial vaccines. However, little is known about the effect of protein assembly structure in immunogenicity and the protection conferred by a vaccine. In this work, rotavirus VP6, a polymorphic protein that assembles into nanotubes, icosahedra (dlRLP) or trimers was used to compare the immune response elicited by three different assemblies. VP6 is the most antigenic and abundant rotavirus structural protein. It has been demonstrated that antibodies against VP6 interfere with the replication cycle of rotavirus, making it a vaccine candidate. Groups of mice were immunized with either nanotubes, dlRLP or trimers and the humoral response (IgG and IgA titers) was measured. Immunized mice were challenged with EDIM rotavirus and protection against rotavirus infection, measured as viral shedding, was evaluated. Immunization with nanotubes resulted in the highest IgG titers, followed by immunization with dlRLP. While immunization with one dose of nanotubes was sufficient to reduce viral shedding by 70%, two doses of dlRLP or trimers were required to obtain a similar protection. The results show that the type of assembly of VP6 results in different humoral responses and protection efficacies against challenge with live virus. This information is important for the design of recombinant vaccines in general.

Propagation of economic shocks in input-output networks: a cross-country analysis.

This paper investigates how economic shocks propagate and amplify through the input-output network connecting industrial sectors in developed economies. We study alternative models of diffusion on networks and we calibrate them using input-output data on real-world inter-sectoral dependencies for several European countries before the Great Depression. We show that the impact of economic shocks strongly depends on the nature of the shock and country size. Shocks that impact on final demand without changing production and the technological relationships between sectors have on average a large but very homogeneous impact on the economy. Conversely, when shocks change also the magnitudes of input-output across-sector interdependencies (and possibly sector production), the economy is subject to predominantly large but more heterogeneous avalanche sizes. In this case, we also find that (i) the more a sector is globally central in the country network, the larger its impact; (ii) the largest European countries, such as those constituting the core of the European Union's economy, typically experience the largest avalanches, signaling their intrinsic higher vulnerability to economic shocks.

Effect of controlled redox potential and dissolved oxygen on the in vitro refolding of an E. coli alkaline phosphatase and chicken lysozyme.

The development of efficient purification strategies of recombinant active protein derived from inclusion bodies requires the knowledge of the effect of environmental variables, such as redox potential (RP) and dissolved oxygen tension (DOT), in order to control the protein folding process. However, that information is scarce and only few in vitro studies of the impact of such variables have been reported under constant controlled conditions. In this work, the effect of controlled RP and DOT on the refolding of E. coli alkaline phosphatase (AP) and chicken lysozyme (CL) enzymes were studied. Disulphide bonds of both enzymes were reduced in an instrumented vessel using 2-mercaptoethanol and nitrogen. In the latter case, guanidine hydrochloride was also used to denature the protein. Such conditions caused protein conformational changes, as determined by the intrinsic fluorescence spectra that correlated with a decrease on the activity in both cases. Reduced enzymes were then oxidized, under different constant and predetermined RP or DOT, by manipulating the gas composition in the vessel. Folding kinetics were followed as the recovery of enzyme activity. Results showed that the percentage of recovery and rate of increase of enzymatic activity directly depended on the RP and DOT. A higher folding efficiency was found under controlled DOT compared to controlled RP conditions. These results are useful for establishing protein folding strategies to improve the recovery of active protein from inclusion bodies.

Fecundidad y participación de la mujer en el mercado laboral en la Costa Caribe y en Colombia / Fertilidade e participação feminina no mercado de trabalho no Litoral Caribenho, e na Colômbia / Fertility and female participation in the labor market in Colombia and its Caribbean Coast

El objetivo del presente artículo es identificar los determinantes que explican las diferencias en las tasas de participación laboral de las mujeres –con y sin hijos– en la Costa Caribe y en Colombia. Para tal propósito se realizaron modelos probit de los determinantes de la participación de cada grupo de mujeres, y se implementó el método de descomposición microeconométrica aplicado a los modelos de elección binaria. Los resultados sugieren a que tanto en la Costa Caribe como en Colombia las variables que explican dichas diferencias son: la escolaridad, la no tenencia de pareja y, en menor medida, la riqueza.

The aim of this article is to identify the determinants of the differences in the labor supply rates between the women with and without children in Colombia and its Caribbean Coasty. In order to achieve this, Probit models about the determinants of the labor supply rate for each group of women were estimated and the microeconometric decomposition method was applied to the binary models. The results suggest that in the Caribbean Coast of Colombia –as well as in the rest of the country- the main variables to explain such differences are: education, being single and wealth in a lesser degree.

O objetivo deste artigo é identificar os fatores que explicam as diferenças nas taxas de participação das mulheres, com e sem filhos, no mercado de trabalho do litoral Caribenho e na Colômbia. Para esse propósito foram elaboradores modelos probit dos fatores determinantes da participação de cada grupo de mulheres, e implementou-se o método de decomposição microeconométrica aplicado aos modelos de escolha binária. Os resultados mostram que tanto no litoral Caribenho como na Colômbia as variáveis que explicam tais diferenças são: a escolaridade, não ter companheiro e, em menor escala, a riqueza.

Cytochrome d but not cytochrome o rescues the toluidine blue growth sensitivity of arc mutants of Escherichia coli.

The Arc (anoxic redox control) two-component signal transduction system, consisting of the ArcB sensor kinase and the ArcA response regulator, allows adaptive responses of Escherichia coli to changes of O(2) availability. The arcA gene was previously known as the dye gene because null mutants were growth sensitive to the photosensitizer redox dyes toluidine blue and methylene blue, a phenotype whose molecular basis still remains elusive. In this study we report that the toluidine blue O (TBO) effect on the arc mutants is light independent and observed only during aerobic growth conditions. Moreover, 16 suppressor mutants with restored growth were generated and analyzed. Thirteen of those possessed insertion elements upstream of the cydAB operon, rendering its expression ArcA independent. Also, it was found that, in contrast to cythocrome d, cythocrome o was not able to confer toluidine blue resistance to arc mutants, thereby representing an intriguing difference between the two terminal oxidases. Finally, a mechanism for TBO sensitivity and resistance is discussed.

The aerobic electron transport system of Eikenella corrodens.

The respiratory system of the fastidious beta-proteobacterium Eikenella corrodens grown with limited oxygen was studied. Membranes showed the highest oxidase activity with ascorbate plus N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) or succinate and the lowest activity with NADH and formate. The presence of a bc1-type complex was suggested by the inhibition exerted by 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), myxothiazol, and antimycin A on respiration with succinate and by the effect of the latter two inhibitors on the succinate-reduced difference spectra. Respiration with succinate or ascorbate-TMPD was abolished by low KCN concentrations, suggesting the presence of a KCN-sensitive terminal oxidase. Cytochromes b and c were spectroscopically detected after reduction with physiological or artificial electron donors, whereas type a and d cytochromes were not detected. The CO difference spectrum of membranes reduced by dithionite and its photodissociation spectrum (77 K) suggested the presence of a single CO compound that had the spectral features of a cytochrome o-like pigment. High-pressure liquid chromatography analysis of membrane haems confirmed the presence of haem B; in contrast, haems A and O were not detected. Peroxidase staining of membrane type c cytochromes using SDS-PAGE revealed the presence of five bands with apparent molecular masses of 44, 33, 30, 26, and 14 kDa. Based on our results, a tentative scheme of the respiratory chain in E. corrodens, comprising (i) dehydrogenases for succinate, NADH, and formate, (ii) a ubiquinone, (iii) a cytochrome bc1, and (iv) a type-cbb' cytochrome c oxidase, is proposed.

Curso de mestrado em enfermagem: opressão e libertação na perspectiva freireana: um estudo comparado entre duas universidades governamentais, Brasil/Perú / The conceptual bases of Master's degree courses between Anna Nery's Nursing School of teh Federal University of Rio de Janeiro and the National University Mayor of San Marcos (Perú)

É uma pesquisa de natureza qualitativa, cujo objeto de estudo foram as bases conceituais do Curso de Mestrado na Escola de Enfermagem Anna Nery da Universidade Federal do Rio de Janeiro-Brasil e na Seção de Mestrado de Enfermagem da Universidade Nacional Mayor de San Marcos-Perú, na perspectiva de estudos comparados latinoamericanos. Os dados foram obtidos através da análise documental e de entrevistas de dez professores e de dez alunos que constituíram-se em fontes primárias. Três foram as categorias temáticas: relação professor-aluno, desenvolvimento do pensamento crítico, desenvolvimento profissiona", que também evidenciaram limitações e sugestões. A análise dessas categorias teve como base os conceitos básicos de Paulo Freire e o enfoque comparado de George Baraday....

An unusual cytochrome o'-type cytochrome c oxidase in a Bacillus cereus cytochrome a3 mutant has a very high affinity for oxygen.

Bacillus cereus strain PYM1 is a mutant unable to synthesize haem A or spectrally detectable cytochromes aa3 or caa3. The nature of the remaining oxidase(s) catalysing oxygen uptake has been studied. Respiratory oxidase activities and the levels of cytochromes b and c increased 2.6- to 4.2-fold on transition from exponential growth, in either of two media, to sporulation stage III, as previously observed for the parent wild-type strain. NADH oxidase activity at both stages of culture was several-fold higher than ascorbate plus tetramethyl-p-phenylenediamine (TMPD) oxidase activity, consistent with the TMPD- phenotype of strain PYM1. Oxidase activity with ascorbate as substrate was significant even in the absence of TMPD as electron mediator, suggesting that the terminal oxidase receives electrons from a cytochrome c. Carbon monoxide (CO) difference spectra of membranes were obtained using various reductants (ascorbate +/- TMPD, NADH, dithionite) and revealed a haemoprotein resembling cytochrome o'. The CO complex of this cytochrome was photodissociable: the photodissociation spectrum (photolysed minus CO-ligated) exhibited a trough at 416 nm and a peak at 436 nm, together with minor features in the alpha/beta region of the spectrum, consistent with the presence of a cytochrome o'-like pigment. CO recombination occurred at -85 to -95 degrees C. No other haemoproteins showing photoreversible CO binding under these conditions were detected. Evidence that this pigment was the oxidase responsible for substrate oxidation was obtained by photodissociating the CO complex at subzero temperatures in the presence of oxygen; this resulted in faster ligand recombination, attributed to oxygen binding, and extensive oxidation of cytochromes c and b. The oxygen affinity of the oxidase was determined by using the deoxygenation of oxyleghaemoglobin as a sensitive reporter of dissociated oxygen concentration. A single oxidase was revealed with a K(m) for oxygen of about 8 nM; this is one of the highest affinities yet reported for a terminal oxidase.