Introducción. Los accidentes causados por animales venenosos ocurren con mucha frecuencia en comunidades pobres con acceso limitado a los servicios de salud. Se les consideran enfermedades desatendidas y son una de las causas importantes de morbimortalidad en varias naciones del mundo, incluida Venezuela.Objetivo. Evaluar la mortalidad por contacto traumático con animales venenosos (serie X20-X29) en Venezuela en el periodo de 2000 a 2009.Materiales y métodos. Los datos se obtuvieron de los anuarios de mortalidad del Ministerio de Salud.Resultados. Se registraron 759 decesos, la mayoría de ellos en el 2009. La primera causa fue la mordedura de serpientes (n=323; 42,6 %), seguida por la picadura de himenópteros (n=170; 22,4 %), la mordedura de centípedos (n=106; 14,0 %) y la picadura de escorpiones (n=76; 10,0 %). La mediana de la tasa de mortalidad general para el periodo fue de 0,285 fallecidos por 100.000 habitantes, en tanto que, por grupo específico, fue de 0,120 para ofidios, de 0,065 para himenópteros, de 0,035 para centípedos y de 0,025 para escorpiones.Conclusión. Al comparar estos datos con los antecedentes históricos, se evidenció la modificación del patrón de mortalidad en el país caracterizada por un aumento significativo de los decesos por centípedos, tercera causa de muerte, lo que reubica la picadura de escorpiones como la cuarta causa de mortalidad.
Phycobilisomes (PBS) are accessory light harvesting protein complexes formed mainly by phycobiliproteins (PBPs). The PBPs absorb light that is efficiently transferred to Photosystems due to chromophores covalently bound to specific cysteine residues. Besides phycobiliproteins (PE), the PBS contains linker proteins responsible for assembly and stabilization of the whole complex and the tuning of energy transfer steps between chromophores. The linker (γ33) from Gracilaria chilensis, is a chromophorylated rod linker associated to (αβ)6 hexamers of R-phycoerythrin (R-PE). Its role in the energy transfer process is not clear yet. Structural studies as well as the composition and location of the chromophores are essential to understand their involvement in the energy transfer process in PBS. To achieve this, the coding gene of γ33 was cloned and sequenced. The sequence was analyzed by informatics tools, to obtain preliminary information which leaded the next experiments. The protein was purified from R-phycoerythrin, and the sequence confirmed by mass spectrometry. The coding sequence analysis revealed a protein of 318 aminoacid residues containing a chloroplastidial transit peptide (cTP) of 39 aminoacids at the N-terminus. The conservation of cysteines revealed possible chromophorylation sites. Using α and β R-PE subunits as spectroscopic probes in denaturation assays, we deduced a double bonded phycourobilin (PUB) on γ33 subunit that were confirmed between Cys62 and Cys73 (DL-PUB62/73) by mass spectrometry. The cysteines involved in the double link are located in a helical region, in a conformation that reminds the position of the DL-PUB50/61 in the β subunit of R-PE. The position of single linked PUB at Cys95 and a single linked PEB at Cys172 were also confirmed. Spectroscopic studies show the presence of both types of chromophores and that there are not energy transfer by FRET among them.
Growth and biochemical composition of Thalassiosira pseudonana (Thalassiosirales: Thalassiosiraceae) cultivated in semicontinuous system at different culture media and irradiances. Thalassiosira pseudonana is a marine Bacillariophyta commonly used as live feed in mariculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, irradiance and nutrient availability. The aim of this study was to investigate the influence of three irradiances (60, 120 and 180μE/m 2 .s) and two culture media (Algal and Humus) on growth and biochemical composition of this diatom. The microalga was grown semicontinuously at a daily renewal rate of fresh media of 30%, 37‰ salinity, 25±1ºC and constant aeration (200mL/min). The cell densities (cel/mL) and contents of protein, lipid, carbohydrate, chlorophyll a, total carotenoids, and fatty acids, showed significant differences (p<0.05) between treatments. During steady-state phase, the maximal cell density, and lipid and carbohydrate contents were of 4.62x10 6 cel/mL, 20.3±2.28% and 16.6±2.43%, respectively, and were achieved in Humus medium at 180μE/ m 2 .s. Moreover, highest protein contents (45.0±5.05%) and total carotenoids (0.5±0.01%) were obtained in Algal medium at 180μE/m 2 .s. Chlorophyll a (0.93±0.04%) was higher at low irradiances in Algal medium. In both media, the fatty acids unsaturation degree was lower with increasing irradiance, being eicosapentaenoic acid, 20:5 n-3 (EPA) most represented (6.20%) in Algal medium at 60μE/m 2 .s. This strain of T. pseudonana showed multiple physiological responses to changes in culture conditions, and may be cultivated with an alternative medium, which reduced the operating costs and allowed a high nutritional biomass production value for animals under culture. Rev. Biol. Trop. 61 (3): 1003-1013. Epub 2013 September 01.
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