Discovery of the ARP2 protein as a determining molecule in tumor cell death

Cancer is a multifactorial disease that constitutes a serious public health problem worldwide. Prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. By studying androgen-independent lymphoid nodule carcinoma of the prostate (LNCaP) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23pS conductance that promotes incoming Ca2+ currents, as well as apoptosis final stages. arp2cDNA was isolated and identified to be of the same cell type, and mRNA was expressed in Xenopus laevis oocytes, which was found to be associated with the activation of incoming Ca2+ currents and induction to apoptosis. cDNA, which encodes the ARP2 protein, was overexpressed in LNCaP cells and Chinese hamster ovary cells, which induced apoptosis. Our evidence suggests that protein ARP2 overexpression and transit to the cell membrane allows an increased Ca2+ incoming current that initiates the apoptosis process in epithelial-type cells whose phenotype shows resistance to programmed cell death.

Desarrollo de un método analítico para la determinación de selenio en huevos fortificados de gallinas (Isa Brown) por espectroscopia de absorción atómica con generación de hidruros / Development of an analytical method for the determination of selenium in fortified hens eggs (Isa Brown) by atomic absorption spectroscopy hydride generation

El huevo es una fuente proteica de uso masivo, en consideración a su bajo costo, es consumido con mayor frecuencia por toda la población. Por esta razón, es de gran interés introducir al mercado un tipo de huevo "saludable", que disminuya los riesgos ligados a enfermedades cardiovasculares y que actúe como antioxidante. Por ello, se evaluó la incorporación del Selenio Orgánico (Sel-Plex®, Alltech Inc) en el programa de alimentación de gallinas ponedoras comerciales raza isa brown con el objeto de obtener huevos fortificados con selenio. Estos fueron evaluados empleando la técnica de espectroscopia analítica con generación de hidruros (HGAAS) y para llevar a cabo la digestión se empleó una mezcla de HNO3/H2O2. El intervalo lineal fue de 6,0 a 200,0 µg/L para el selenio. Con un límite detección de 0,11 µg/L. La precisión de 0,82% y la recuperación de 97-104,4% y una frecuencia de análisis de 24 muestras/hora. La principal ventaja de este método es la determinación de selenio en huevo completo. Los resultados indican que luego de un período de 12 semanas la concentración de selenio es de 62,45 de mg Selenio/huevo lo que muestra que estos proporcionan los requerimientos necesarios. Por lo tanto los huevos enriquecidos en Venezuela contribuirían a mejorar la dieta diaria de estos consumidores.

The egg is a protein source for mass use, considering its low cost, is most commonly consumed by the population. For this reason, it is of great interest to enter the market a type of egg "healthy" to decrease the risks associated with cardiovascular disease and act as an antioxidant. Therefore, it evaluated the incorporation of organic selenium (Sel-Plex ®, Alltech Inc.) in the feeding program commercial layers “Isa Brown” race in order to obtain eggs fortified with selenium. These were assessed using analytical technique spectroscopy with hydride generation (HGAAS) and to conduct the digestion was used a mixture of HNO3/H2O2. The linear range was from 6.0 to 200.0 mg / L for selenium. With detection limit of 0.11 mg / L 0.82% accuracy and recovery of 97 to 104.4% and a frequency analysis of 24 samples / hour. The main advantage of this method is the determination of selenium in whole egg. The results indicate that after a period of 12 weeks the concentration of selenium is 62.45 Selenium mg / egg showing that these provide the necessary requirements. Therefore enriched eggs in Venezuela would help improve the diet of these consumers.

Superovulation in vesper mouse Calomys musculinus (Rodentia-Sigmodontinae)

Optimal conditions for pharmacological induction of ovulation of vesper mouse, Calomys musculinus, were analyzed. The best superovulation (a mean of about 21 eggs per female, range 12-45) was induced by the administration of 12 IU of PMSG followed 48 hr later by injection of 15 IU of hCG. Ovulation started about 10 hr after administration of hCG and was completed during the next 4-5 hr. The induction of ovulation was achieved irrespective of the stage of the oestrus cycle at the moment of PMSG administration. The majority of females (105, 82.7) responded to the treatment with either an ovulatory (53.4) or superovulatory (49.7) response. Oocyte recovery and egg quality were clearly influenced by the age of females, 30 days to more than 120 days old. The majority (90.3) of superovulated eggs was morphologically normal, and only a small proportion of eggs showed morphological abnormalities (7.4) or were spontaneously activated (2.3). Superovulated oocytes under these conditions, were able to undergo normal fertilization in vitro. After 6 hr of sperm-egg interaction in vitro, 87.5 of the oocytes had extruded the second polar body and/or developed pronuclei

Response of gravid Phlebotmus papatasi females to an oviposition attractant/stimulant associated with conspecific eggs.

Oviposition response of gravid P. papatasi females to conspecific eggs was studied in laboratory colonized sandflies. It was observed that significantly higher number of eggs were laid in the vicinity of conspecific eggs. However, a certain minimum number of eggs were required to be placed on the substratum to influence the rate of oviposition. The fecundity of females (mean = 56.5 +/- 4.9 eggs) exposed to conspecific eggs was significantly higher (P < 0.05) than that of blank control group. Perhaps, the chemical substances/pheromone of egg origin stimulated the oviposition rate. In an attempt to isolate the active ingredient, solvent washing of the conspecific eggs were tested. No increase in the rate of oviposition was noticed when the test site was treated with distilled water extract, whereas, significantly larger number of eggs were laid at the site treated with di-ethyl ether extract. This indicated that the oviposition attractant associated with the eggs dissolved in the organic solvent, but not in water. The possible application of this attractant for wild sandflies in nature and for regulating the site of oviposition on the substratum in the laboratory colonized sandflies needs to be explored.

The in Vitro Maturation of the Mouse Oocyte

Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.

The in Vitro Maturation of the Mouse Oocyte

Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.