Recognition of apoptotic cells by viable cells is specific,ubiquitous, and species independent: analysis using photonic crystal biosensors

Apoptotic recognition is innate and linked to a profound immune regulation (innate apoptotic immunity [IAI]) involving anti-inflammatory and immunosuppressive responses. Many of the molecular and mechanistic details of this response remain elusive. Although immune outcomes can be quantified readily, the initial specific recognition events have been difficult to assess. We developed a sensitive, real-time method to detect the recognition of apoptotic cells by viable adherent responder cells, using a photonic crystal biosensor approach. The method relies on characteristic spectral shifts resulting from the specific recognition and dose-dependent interaction of adherent responder cells with nonadherent apoptotic targets. Of note, the biosensor provides a readout of early recognition-specific events in responder cells that occur distal to the biosensor surface. We find that innate apoptotic cell recognition occurs in a strikingly species-independent manner, consistent with our previous work and inferences drawn from indirect assays. Our studies indicate obligate cytoskeletal involvement, although apoptotic cell phagocytosis is not involved. Because it is a direct, objective, and quantitative readout of recognition exclusively, this biosensor approach affords a methodology with which to dissect the early recognition events associated with IAI and immunosuppression.     

The ADP/ATP Carrier and Its Relationship to Oxidative Phosphorylation in Ancestral Protist Trypanosoma brucei

The highly conserved ADP/ATP carrier (AAC) is a key energetic link between the mitochondrial (mt) and cytosolic compartments of all aerobic eukaryotic cells, as it exchanges the ATP generated inside the organelle for the cytosolic ADP. Trypanosoma brucei, a parasitic protist of medical and veterinary importance, possesses a single functional AAC protein (TbAAC) that is related to the human and yeast ADP/ATP carriers. However, unlike previous studies performed with these model organisms, this study showed that TbAAC is most likely not a stable component of either the respiratory supercomplex III+IV or the ATP synthasome but rather functions as a physically separate entity in this highly diverged eukaryote. Therefore, TbAAC RNA interference (RNAi) ablation in the insect stage of T. brucei does not impair the activity or arrangement of the respiratory chain complexes. Nevertheless, RNAi silencing of TbAAC caused a severe growth defect that coincides with a significant reduction of mt ATP synthesis by both substrate and oxidative phosphorylation. Furthermore, TbAAC downregulation resulted in a decreased level of cytosolic ATP, a higher mt membrane potential, an elevated amount of reactive oxygen species, and a reduced consumption of oxygen in the mitochondria. Interestingly, while TbAAC has previously been demonstrated to serve as the sole ADP/ATP carrier for ADP influx into the mitochondria, our data suggest that a second carrier for ATP influx may be present and active in the T. brucei mitochondrion. Overall, this study provides more insight into the delicate balance of the functional relationship between TbAAC and the oxidative phosphorylation (OXPHOS) pathway in an early diverged eukaryote.     

Structure of muramic acid TMS derivative mass spectrum's base ion (m/z=185) used for quantification of bacterial peptidoglycan.

The use of trimethylsilyl (TMS)-derivatisation for determining muramic acid in environmental and clinical samples by gas chromatography-mass spectrometry provides high detection sensitivity; however, questions have been raised as concerns the chemical structure of the entity giving the strong signal of m/z 185. In the present communication we present evidence that this entity results from the formation of a lactam structure of muramic acid upon derivatisation.     

Peroxidase deficiency of nickel-transformed hamster cells correlates with their increased resistance to cytotoxicity of peroxides

Using a procedure aimed at isolation of genes that are inactivated during nickel-induced carcinogenesis in Chinese hamster cells, a homolog of genes encoding human and mouse heme containing peroxidases has been cloned. Northern blot analysis of normal cultured fibroblasts and two nickel-transformed cell lines confirmed that this gene was expressed in normal but not in transformed cells. Nickel-transformed cells also tested negative for peroxidase activity using a sensitive fluorescence assay. Cultured embryo cells or fibroblasts that express peroxidase activity and their nickel-transformed peroxidase-deficient counterparts were employed to investigate the role of peroxidase-catalyzed processes in cytotoxicity induced by tert-butyl hydroperoxide or cumene hydroperoxide. It has been found that peroxidase-deficient cells were significantly more resistant to cytotoxic effect of these compounds suggesting that cytotoxic effect of hydroperoxides may be mediated in part by free radicals generated in the course of peroxidase-catalyzed reactions.     

Effects of dietary protein and carbohydrate on life‐history traits and body protein and fat contents of the black soldier fly Hermetia illucens

We investigate how the black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae) responds to dietary protein (P) and carbohydrate (C) contents and the P:C ratio in terms of both immature and adult life‐history traits, as well as effects on larval body composition. Nine chicken‐feed based diets varying in their P:C ratio are formulated. We test three protein concentrations (10%, 17% and 24%) and three carbohydrate concentrations (35%, 45% and 55%) and their combinations. All nine diets support the complete development and reproduction of this species. Survival is high on all diets. Development time, larval yield, larval crude fat and egg yield are more influenced by P and C contents than by the P:C ratio. Low contents result in a shorter development time. Larval yield is higher on diets with higher C‐contents. Pupal development is faster on a low dietary P‐content for all three C‐contents. Egg yield only increases when P‐content increases, although it also varies with the P:C ratio. Larval crude protein content is similar on all nine diets but increases when C‐content is low (10%) in P10 and P17. Larval crude fat content is high at P24‐diets irrespective of C‐content. We conclude that a high macronutrient content combined with a low P:C ratio positively affects H. illucens performance. The diet P17:C55 supports the highest larval and adult performance and results in a high larval body protein content and an intermediate crude fat content.     

Calidad de las imágenes,la lectura y el servicio de mamografía en cuatro centros de imagenología de Manizales,Colombia

IntroducciónLa calidad de la mamografía está directamente relacionada con la capacidad para detectar anormalidades y, por ello, es necesario el control de calidad en los centros de imágenes diagnósticas.ObjetivoEvaluar la calidad de la imagen, la lectura y el servicio de mamografía de algunos centros de imágenes diagnósticas en Manizales, Colombia.Materiales y métodosCuatro centros participaron de forma voluntaria y bajo acuerdos de confidencialidad en el estudio. De las 520 mujeres atendidas en ellos, a 318 se les hicieron mamografías. A partir de una inspección visual del servicio, se evaluaron la infraestructura, la tecnología y el personal de la unidad. Un radiólogo experto en lectura e interpretación clínica de imágenes mamarias evaluó la calidad de la imagen y la de su lectura. El análisis estadístico se hizo utilizando un anova y determinando el índice kappa y el porcentaje de desacuerdo.ResultadosSe encontró falta de calidad de las imágenes obtenidas, principalmente, por presencia de artificios en el 75% de ellas, e identificación y rotulación deficientes; además, en la toma de la proyección oblicua medio-lateral, se encontró falta de visualización del ángulo inframamario. El grado de concordancia en el reporte BI-RADS fue bajo en los cuatro centros, con diferencias importantes en el informe y la descripción de los hallazgos.ConclusiónLos centros de imágenes diagnósticas evaluados están habilitados para el funcionamiento, pero se encontraron deficiencias importantes en la calidad de las imágenes y en su lectura, lo que pone de manifiesto la necesidad de establecer estándares de calidad y mejorar los aspectos que se puedan mejorar.Palabras clave: mamografía, gestión de la calidad, diagnóstico por imagen, garantía de la calidad de atención de salud, servicio de mantenimiento e ingeniería en hospital, ingeniería biomédica     

Regioselective Mitsunobu Reaction of Partially Protected Uridine

Mitsunobu reaction of partially acylated uridine proceeds with high regioselectivity for intramolecular S_N2 anhydro linkage closuring. Under the reaction conditions, an isomeric mixture of diacyl uridine derivatives with either free 2′- or 3′-hydroxyl group was transformed into a single cyclonucleosidic product, 2,2′-anhydro-3′,5′-di-O-acyluridine. This paper presents a possible mechanism of the reactions, the explanation of observed phenomenon based on semiempirical and density functional theory (DFT) calculations and possible utility of this synthetic pathway.