Insights into Streptomyces coelicolor A3(2) growth and pigment formation with high-throughput online monitoring.

Streptomyces species are intensively studied for their ability to produce a variety of natural products. However, conditions influencing and leading to product formation are often not completely recognized. Therefore, in this study, high-throughput online monitoring is presented as a powerful tool to gain in-depth understanding of the cultivation of the model organism Streptomyces coelicolor A3(2). Through online measurements of oxygen transfer rate and autofluorescence, valuable information about availability of nutrients and product formation patterns of the pigments actinorhodin and undecylprodigiosin can be obtained and explained. Therefore, it is possible to determine the onset of pigmentation and to study in detail the influencing factors thereof. One factor identified in this study is the filling volume of the cultivation vessel. Slight variations led to varying pigmentation levels. By combining optical and metabolic online monitoring techniques, the correlation of the filling volume with pigmentation could be explained as a result of different growth trajectories caused by varying specific power inputs and their influence on the pellet formation of the filamentous system. Finally, experiments with the addition of supernatant from unpigmented and pigmented cultures could highlight the applicability of the presented approach to study quorum sensing and cell-cell interaction.

Tunable population dynamics in a synthetic filamentous coculture.

Microbial cocultures are used as a tool to stimulate natural product biosynthesis. However, studies often empirically combine different organisms without a deeper understanding of the population dynamics. As filamentous organisms offer a vast metabolic diversity, we developed a model filamentous coculture of the cellulolytic fungus Trichoderma reesei RUT-C30 and the noncellulolytic bacterium Streptomyces coelicolor A3(2). The coculture was set up to use α-cellulose as a carbon source. This established a dependency of S. coelicolor on hydrolysate sugars released by T. reesei cellulases. To provide detailed insight into coculture dynamics, we applied high-throughput online monitoring of the respiration rate and fluorescence of the tagged strains. The respiration rate allowed us to distinguish the conditions of successful cellulase formation. Furthermore, to dissect the individual strain contributions, T. reesei and S. coelicolor were tagged with mCherry and mNeonGreen (mNG) fluorescence proteins, respectively. When evaluating varying inoculation ratios, it was observed that both partners outcompete the other when given a high inoculation advantage. Nonetheless, adequate proportions for simultaneous growth of both partners, cellulase, and pigment production could be determined. Finally, population dynamics were also tuned by modulating abiotic factors. Increased osmolality provided a growth advantage to S. coelicolor. In contrast, an increase in shaking frequency had a negative effect on S. coelicolor biomass formation, promoting T. reesei. This comprehensive analysis fills important knowledge gaps in the control of complex cocultures and accelerates the setup of other tailor-made coculture bioprocesses.

Reliable online measurement of population dynamics for filamentous co-cultures.

Understanding population dynamics is a key factor for optimizing co-culture processes to produce valuable compounds. However, the measurement of independent population dynamics is difficult, especially for filamentous organisms and in presence of insoluble substrates like cellulose. We propose a workflow for fluorescence-based online monitoring of individual population dynamics of two filamentous microorganisms. The fluorescent tagged target co-culture is composed of the cellulolytic fungus Trichoderma reesei RUT-C30-mCherry and the pigment-producing bacterium Streptomyces coelicolor A3(2)-mNeonGreen (mNG) growing on insoluble cellulose as a substrate. To validate the system, the fluorescence-to-biomass and fluorescence-to-scattered-light correlation of the two strains was characterized in depth under various conditions. Thereby, especially for complex filamentous microorganisms, microbial morphologies have to be considered. Another bias can arise from autofluorescence or pigments that can spectrally interfere with the fluorescence measurement. Green autofluorescence of both strains was uncoupled from different green fluorescent protein signals through a spectral unmixing approach, resulting in a specific signal only linked to the abundance of S. coelicolor A3(2)-mNG. As proof of principle, the population dynamics of the target co-culture were measured at varying inoculation ratios in presence of insoluble cellulose particles. Thereby, the respective fluorescence signals reliably described the abundance of each partner, according to the variations in the inocula. With this method, conditions can be fine-tuned for optimal growth of both partners along with natural product formation by the bacterium.

Mortality due to acute adverse drug reactions in Galicia: 1997-2011. / Mortalidad por reacción aguda tras consumo de drogas en Galicia: 1997-2011.

The aim of this research is to study all people who died in the Autonomous Community of Galicia from acute death after drugconsumption (ADR) in which there was judicial intervention during the period from 1997 to 2011, according to inclusion and exclusión criteria established by the National Drug Plan for the entire national territory. Sociodemographic and clinical characteristics of deceased subjects were studied, in order to identify key risk factors and/or vulnerable populations.A total of 805 deaths were recorded. The distribution by provinces and municipalities corresponds to the areas of greatest population, incidence of consumption and proximity to the coast. The average age of these patients was 34.34 years, with a gradual increase over years. Most of them were male (91.2%) and single (47.7). 43.5% of the deceased habitually used the parenteral route of administration and 36.4% had positive HIV serology. The most frequently-detected substances corresponded to opiates (heroin: 61.3%, methadone: 35.6%), followed by cocaine (53.7%), although the most common pattern was that of poly-consumption. ADR mortality figures remain relatively stable throughout the study period. The predominant pattern is that of males, opiates and a long history of consumption.

Se estudian todos los sujetos fallecidos en Galicia por reacción aguda tras consumo de drogas (RAD) en los que existe intervención judicial a lo largo del periodo 1997-2011, según los criterios establecidos por el Plan Nacional sobre Drogas para todo el territorio nacional. Se recogieron y analizaron variables sociodemográficas, clínicas y toxicológicas de cada uno de los casos. El objetivo fundamental es tratar de determinar los principales factores de riesgo y/o perfil de las poblaciones vulnerables, así como sugerir medidas preventivas. En total se registran 805 fallecimientos. La edad media de los fallecidos fue de 34,34 años, con un aumento progresivo a lo largo de los años. La mayoría eran varones (91,2%) y solteros (47,7%). El 43,5% de los fallecidos utilizaban la vía de administración parenteral y un 36,4% presentaban serología positiva frente al VIH. Las sustancias detectadas con más frecuencia correspondían a opiáceos (heroína: 61,3%, metadona: 35,6%), seguidos de cocaína (53,7 %), aunque el patrón más habitual era el policonsumo. Las cifras de mortalidad por RAD se mantienen relativamente estables a lo largo del periodo de estudio. El patrón predominante es el de varones, consumidores de opiáceos y con larga historia de consumo.

Mortalidad por reacción aguda tras consumo de drogas en Galicia: 1997-2011 / Mortality due to acute adverse drug reactions in Galicia; 1997-2011

Se estudian todos los sujetos fallecidos en Galicia por reacción aguda tras consumo de drogas (RAD) en los que existe intervención judicial a lo largo del periodo 1997-2011, según los criterios establecidos por el Plan Nacional sobre Drogas para todo el territorio nacional. Se recogieron y analizaron variables sociodemográficas, clínicas y toxicológicas de cada uno de los casos. El objetivo fundamental es tratar de determinar los principales factores de riesgo y/o perfil de las poblaciones vulnerables, así como sugerir medidas preventivas. En total se registran 805 fallecimientos. La edad media de los fallecidos fue de 34,34 años, con un aumento progresivo a lo largo de los años. La mayoría eran varones (91,2%) y solteros (47,7%). El 43,5% de los fallecidos utilizaban la vía de administración parenteral y un 36,4% presentaban serología positiva frente al VIH. Las sustancias detectadas con más frecuencia correspondían a opiáceos (heroína: 61,3%, metadona: 35,6%), seguidos de cocaína (53,7 %), aunque el patrón más habitual era el policonsumo. Las cifras de mortalidad por RAD se mantienen relativamente estables a lo largo del periodo de estudio. El patrón predominante es el de varones, consumidores de opiáceos y con larga historia de consumo

The aim of this research is to study all people who died in the Autonomous Community of Galicia from acute death after drug consumption (ADR) in which there was judicial intervention during the period from 1997 to 2011, according to inclusion and exclusion criteria established by the National Drug Plan for the entire national territory. Sociodemographic and clinical characteristics of deceased subjects were studied, in order to identify key risk factors and/or vulnerable populations. A total of 805 deaths were recorded. The distribution by provinces and municipalities corresponds to the areas of greatest population, incidence of consumption and proximity to the coast. The average age of these patients was 34.34 years, with a gradual increase over years. Most of them were male (91.2%) and single (47.7). 43.5% of the deceased habitually used the parenteral route of administration and 36.4% had positive HIV serology. The most frequently-detected substances corresponded to opiates (heroin: 61.3%, methadone: 35.6%), followed by cocaine (53.7%), although the most common pattern was that of poly-consumption. ADR mortality figures remain relatively stable throughout the study period. The predominant pattern is that of males, opiates and a long history of consumption

Antimicrobial activity of nisin adsorbed to surfaces commonly used in the food industry.

The adsorption isotherms of nisin to three food contact surfaces, stainless steel, polyethyleneterephthalate (PET), and rubber at 8, 25, 40, and 60 degrees C, were calculated. For all surfaces, the increase in temperature led to a decrease in the affinity between nisin and the surface. The rubber adsorbed a higher amount of nisin (0.697 microg/cm2) in comparison with PET (0.665 microg/cm2) and stainless steel (0.396 microg/cm2). Adsorption of nisin to the stainless steel surface described L-2 type curves for all temperatures assayed. However, for PET and rubber surfaces, the isotherms were L-2 type (at 40 and 60 degrees C) and L-4 type curves (at 8 and 25 degrees C). Nisin retained its antibacterial activity once adsorbed to the food contact surfaces and was able to inhibit the growth of Enterococcus hirae CECT 279 on Rothe agar medium. The attachment of three Listeria monocytogenes strains to the three surfaces was found to be dependent on the surface, the strain, and the initial bacterial suspension in contact with the surface. The adsorption of Nisaplin on surfaces reduced the attachment of all L. monocytogenes strains tested. The effect of PET-based bioactive packaging in food was very encouraging. When applied to a food system, nisin-adsorbed PET bottles reduced significantly (P < 0.05) the levels of the total aerobic plate counts in skim milk by approximately 1.4 log units after 24 days of refrigerated storage (4 degrees C), thus extending its shelf life.

Toxoplasmosis adquirida durante el embarazo, en el Instituto Materno Infantil en Bogotá / Acquired toxoplasmosis during pregnancy at the Instituto Materno-Infantil, Bogota

La frecuencia de la toxoplasmosis adquirida durante el embarazo, en Bogotá no se conoce con precisión. El Instituto Materno Infantil de la ciudad atiende una población de alto riesgo obstétrico y estrato socioeconómico bajo. Este estudio tuvo como objetivo determinar la frecuencia de madres con marcadores serológicos de infección reciente (IgM e IgA anti-Toxoplasma), que indican riesgo de transmisión congénita, con el fin de estimar la magnitud del problema en las gestantes del IMI. Durante el periodo de julio a diciembre de 1998 se recolectaron 637 muestras de suero de todas las pacientes que consultaban el programa de control prenatal del IMI. Todos los sueros de las gestantes se estudiaron por la técnica IFI-IgG anti-Toxoplasma y aquellas con resultados iguales o superiores a 1:1024 fueron estudiadas por la técnica ISAgA para IgM e IgA anti-Toxoplasma. En total 301 sueros fueron reactivos por IFI-IgG (47/100), 92 tuvieron títulos iguales o superiores a 1:1024. De estos últimos, 14 presentaron pruebas IgM e IgA anti-Toxoplasma positivas, lo que significa que 2,2/100 cumplen criterios de toxoplasmosis reciente. Estos resultados contrastan con reportes previos realizados en otras poblaciones de gestantes de Bogotá y justifican la realización de programas específicos de control.