The Antioxidant Role of Xanthurenic Acid in the Aedes aegypti Midgut during Digestion of a Blood Meal

In the midgut of the mosquito Aedes aegypti, a vector of dengue and yellow fever, an intense release of heme and iron takes place during the digestion of a blood meal. Here, we demonstrated via chromatography, light absorption and mass spectrometry that xanthurenic acid (XA), a product of the oxidative metabolism of tryptophan, is produced in the digestive apparatus after the ingestion of a blood meal and reaches milimolar levels after 24 h, the period of maximal digestive activity. XA formation does not occur in the White Eye (WE) strain, which lacks kynurenine hydroxylase and accumulates kynurenic acid. The formation of XA can be diminished by feeding the insect with 3,4-dimethoxy-N-[4-(3-nitrophenyl)thiazol-2-yl] benzenesulfonamide (Ro-61-8048), an inhibitor of XA biosynthesis. Moreover, XA inhibits the phospholipid oxidation induced by heme or iron. A major fraction of this antioxidant activity is due to the capacity of XA to bind both heme and iron, which occurs at a slightly alkaline pH (7.5-8.0), a condition found in the insect midgut. The midgut epithelial cells of the WE mosquito has a marked increase in occurrence of cell death, which is reversed to levels similar to the wild type mosquitoes by feeding the insects with blood supplemented with XA, confirming the protective role of this molecule. Collectively, these results suggest a new role for XA as a heme and iron chelator that provides protection as an antioxidant and may help these animals adapt to a blood feeding habit

Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis

<p>Abstract</p> <p>Background</p> <p>The mosquito <it>A. aegypti </it>is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of <it>A. aegypty </it>life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during <it>A. aegypti </it>embryogenesis are unknown.</p> <p>Results</p> <p>Glucose metabolism was investigated throughout <it>Aedes aegypti </it>(Diptera) embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE) and germ band retraction (GBr, 24 HAE) may be considered landmarks regarding glucose 6-phosphate (G6P) destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH) activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP), of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK) activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK) and pyruvate kinase (PK) activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3) activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis.</p> <p>Conclusions</p> <p>The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose metabolism during <it>Aedes aegypti </it>embryogenesis. Furthermore, the results also suggest a role for GSK3 in glycogen balance/distribution during morphological modifications.</p

Structural analysis of Fe Mn O nanoparticles in glass ceramics by small angle scattering

Magnetic nanocrystals containing Fe and Mn were obtained by annealing of silicate glasses with the composition 13.6Na2O 62.9SiO2 8.5MnO 15.0Fe2O3 x mol at 580 C for different periods of time. Here, we present Small Angle Neutron Scattering using Polarized neutrons SANSPOL and Anomalous Small Angle X ray Scattering ASAXS investigation on these glass ceramic samples. Analysis of scattering data from both methods reveals the formation of spherical core shell type of nanoparticles with mean sizes between 10nm and 100 nm. ASAXS investigation shows the particles have higher concentration of iron atoms and the shell like region surrounding the particles is enriched in SiO2. SANSPOL investigation shows the particles are found to be magnetic and are surrounded by a nonmagnetic shell like region

Innovations and diversifications toward sustainable Bulgarian agriculture

This article proposes an interpretation of the process of adopting innovations and farm manager perceptions of innovations and diversification in Bulgarian agriculture. Bulgarian agriculture is operating in new macro-conditions since Bulgaria joined the EU. This paper shows the main trends of agricultural sector and the level of diversification of the activities, which also is the aim of the study. It represents the adoption of innovation as a possibility for farm development using the collected data. The well-known models of farm management are not bringing the required profit of agricultural activities every time. Furthermore, the scarcity of resources and the increasing need for environmental protection lead to a search for innovative processes and techniques for reaching decent development in the sector. There is a link between the farmer’s age and the willingness to innovate the activities. The main findings show that farmers under 50 are more likely to adopt innovations. Around 37% of the farmers are planning to adopt innovations. The paper outlines some factors that are constraining the processes. Other evidences show that some diverse activities in Bulgaria are an innovation for the area. The innovative activities are: provision of health, social or educational services, snow cleaning, craftsmanship and restaurant services, rural tourism, etc. The methodological framework is based on the following logic: theoretical review of innovation and item discussing the diversification as an innovative concept in agriculture; the state and condition of the Bulgarian agriculture; evaluation of some factors influencing innovative processes in the agriculture based on own survey; evidence of diversification activities based on statistics and own research. According to the analysed information some general conclusions are made

Assay to visualize specific protein oxidation reveals spatio-temporal regulation of SHP2

Protein-tyrosine phosphatases (PTPs) are thought to be major targets of receptor-activated reactive oxygen species (ROS). Here the authors describe a method that allows the localized visualization of oxidized intermediates of PTPs inside cells during signaling, and provide support for the “redoxosome” model

Magnetic nanocrystals embedded in silicate glasses studied by polarized SANS

Fe Mn O magnetic nanocrystals precipitate in a glass system SiO2 Na2O Fe2O3 MnO during thermal annealing for different periods of time. We report here small angle neutron scattering investigations using polarized neutrons pSANS on these glass samples. Analysis of scattering data reveals the formation of spherical core shell particles. The core of the particle is found to be magnetic and it is surrounded by a non magnetic shell like region. The size parameters of the nanocrystals calculated by pSANS data analyses are comparable with the small angle X ray scattering SAXS investigations, previously reported. Contrary to other glasses in the studied system the diffusion of Fe and Mn ions is not impaired by a rigid shell. This is explained by decreasing of the glass transition temperature of the shell region while its composition departs from that of the matri

Transient perivascular inflammation of the carotid artery—A transient but potentially recurrent disease

Key Clinical Message Transient perivascular inflammation of the carotid artery (TIPIC syndrome) is a rare, unclassified vascular syndrome that usually affects the distal part of the common carotid artery and has a favorable prognosis. The disease is often misdiagnosed even by neurologists due to the moderate intensity of clinical symptoms and their transient character. We present a case of a 52‐year‐old man who experienced two episodes of transient neck pain and moderate local tenderness one and a half years apart. Different imaging modalities, such as ultrasound, CT angiography, and high‐resolution 3T MR, were applied to better visualize the perivascular inflammation of the common carotid arteries. Based on the clinical‐radiological characteristics of our case and applying the diagnostic criteria, we established the diagnosis of TIPIC syndrome. The patient was treated with nonsteroidal anti‐inflammatory drugs for few weeks, and reduction in perivascular changes was observed in both episodes. The case raises questions about the phases of the disease, its duration and the intervals between follow‐ups. Our article also increases the awareness of this rare clinical‐radiological entity and presents recent data from the literature

Structural analysis of magnetic nanocrystals embedded in silicate glasses by anomalous small angle X ray scattering

The present work reports the structural analysis of magnetic nanocrystals of Fe and Mn containing phases formed during annealing of the glass 13.6Na2O 62.9SiO2 8.5MnO 15.0Fe2O3 x mol at 823 K for different periods of time. X ray diffraction investigation shows the formation of a mixture of MnFe2O4 and Fe3O4 phases. Furthermore, small angle X ray scattering and anomalous small angle X ray scattering ASAXS experiments were used to extract quantitative information about the structure of the formed nano sized crystals, as well as their phase compositions, volume fractions and size distributions. ASAXS analysis reveals the formation of spherical core shell particles with the size of the particles between 10 and 50 nm. The concentrations of iron atoms in the core are higher than those in the shell and in the remaining matrix. With increasing annealing time, the ratio of Mn to Fe increases in the nanoparticles and the crystalline phase moves toward the pure jacobsite phase. Evaluated compositions reveal the presence of SiO2 in the shell. This shell acts as a diffusion barrier for the nanocrystal forming ions, and the growth of the particles is kinetically constraine

Effect of whole body vibration on the myelination in the injured spinal cord of adult rats: quantification of luxol fast blue staining

University, Varna, Bulgaria; Institute of Anatomy, Cologne University, Cologne, Germany; Email: [email protected])Whole-body vibration (WBV) is a relatively novel form of exercise used to improve neuromuscular performance in healthy individuals. Its usefulness as a therapy for patients with neurological disorders, in particular spinal cord injury (SCI), has received little attention in clinical settings and, surprisingly, even less in animal SCI models. We performed severe compression SCI at a low-thoracic level in Wistar rats followed by daily WBV starting 1, 7, 14 or 28 days after injury (WBV1, WBV7, WBV14 and WBV28, respectively) and continued over a 12-week post-injury period. As controls served rats euthanized in the first 2 weeks post SCI (subacute), with no WBV training (Sham), treated with passive flexion-extension (PFE) and intact animals. The changes in the average optical density (OD/µm2) of luxol fast blue stained longitudinal sections were used to assess the (re)myelination in the injured spinal cord. Three Regions of Interest (RoIs) were considered: (i) area with visible damage; (ii) proximal and distal region, adjacent to the damage (penumbra);  (iii) visibly undamaged area distally and proximally to the lesion site. The average OD in the damaged areas was low in all animals as compared to intact animals; there were no differences among the treatment groups. The preliminary analysis of the ODs show that WBV7 and WBV14 enhanced remyelination in the penumbra and in the distant seemingly intact regions. Furthermore, OD in the distant regions of the WBV7 group did not differ from the OD in intact spinal cords. Further refinement of the method is needed in order to accurately evaluate this phenomenon