Formation of regulatory patterns during signal propagation in a Mammalian cellular network

We developed a model of 545 components (nodes) and 1259 interactions representing signaling pathways and cellular machines in the hippocampal CA1 neuron. Using graph theory methods, we analyzed ligand-induced signal flow through the system. Specification of input and output nodes allowed us to identify functional modules. Networking resulted in the emergence of regulatory motifs, such as positive and negative feedback and feedforward loops, that process information. Key regulators of plasticity were highly connected nodes required for the formation of regulatory motifs, indicating the potential importance of such motifs in determining cellular choices between homeostasis and plasticity.     

Humoral immune response of water buffalo monitored with three different antigens of Toxocara vitulorum

Humoral immune response of water buffalo naturally infected with Toxocara vitulorum was monitored using three different antigens of this parasite in serum and colostrum of buffalo cows and calves. Soluble extract (Ex) and excretory/secretory (ES) larval antigens and perienteric fluid antigen (Pe) of adult T. vitulorum were used to measure the antibody levels by an indirect ELISA. Serum of 7-12 buffalo cows for the first 365 days and colostrum of the same number of buffalo cows for the first 60 days of parturition, and serum of 8-10 buffalo calves for the first 365 days after birth were assayed. The ELISA detected antibodies against all three T. vitulorum antigens in the colostrum and serum of 100% of buffalo cows and calves examined. The highest antibody levels against Ex, ES and Pe antigens were detected in the buffalo cow sera during the perinatal period and were maintained at high levels through 300 days after parturition. On the other hand, colostrum antibody concentrations of all three antigens were highest on the first day post-parturition, but decreased sharply during the first 15 days. Concomitantly to the monitoring of immune response, the parasitic status of the calves was also evaluated. In calves, antibodies passively acquired were at the highest concentrations 24 h after birth and remained at high levels until 45 days coincidentally with the peak of T. vitulorum infection. The rejection of the worms by the calves occurred simultaneously with the decline of antibody levels, which reached their lowest levels between 76 and 150 days. Thereafter, probably because of the presence of adults/larvae stimulation, the calves acquired active immunity and the antibodies started to increase slightly in the serum and plateaued between the days 211 and 365. All three antigens were detected by the serum antibodies of buffalo calves; however, the concentration of anti-Pe antibody was higher than anti-EX and anti-ES, particularly after 90 days of age. By conclusion, the buffalo cows develop immunity and keep high levels of antibodies against T. vitulorum-Ex, ES and Pe antigens and these antibodies are transferred to their calves through the colostrum. This passively acquired immunity does not protect the calves against the acquisition of the infection, but these antibodies, passively or actively acquired, may have an important role during worm rejection by the calves and prevention of intestinal reinfection.     

The urogenital papillae as an indicator of sexual maturity in male African catfish,Clarias gariepinus, (Burchell, 1822)

The present study investigated a non‐invasive method based on macroscopic morphological features of male Clarias gariepinus for the assessment of sexual maturity stage. As African catfish cannot be stripped for semen as in most other fish species; they have to be killed to obtain semen from the testes. This method could be used to ensure that males used to obtain sperm are sexually mature to increase the concentration and quality of mature sperm for egg fertilization in the production of C. gariepinus. Morphological features including the length and width of the urogenital papillae (UGP), an external secondary sexual characteristic of C. gariepinus (n = 89) were measured and calculated as a percentage of total body length. The urogenital papillae length (L_UGP) and width (W_UGP) index of each fish were used and compared with the macroscopic and microscopic maturity stage of the testes. The results revealed that although positive, a significant correlation does not exist between the L_UGP or W_UGP and maturity stage of the testes. Therefore, although this procedure would be valuable as an initial non‐invasive assessment of maturity, it does not provide an accurate or reliable indication of the maturity stage of the fish.     

Pomegranate Juice and Peel Extracts are Able to Inhibit Proliferation,Migration and Colony Formation of Prostate Cancer Cell Lines and Modulate the Akt/mTOR/S6K Signaling Pathway

Plant Foods for Human Nutrition - Pomegranate (Punica granatum) is known to contain polyphenols with many potential health benefits, including anti-tumoral, anti-inflammatory, and anti-microbial...     

Nitrogenase activity on the roots of tropical forage grasses

Nitrogen fixation in the rhizospheres of field grown tropical forage grasses was studied by the acetylene reduction method. Values varied considerably between sites but indicate the possible economic importance of several of the species studied. Maximal nitrogenase activity measured (nmoles C₂H₄g^?1 dry roots h^?1) was 754 for Pennisetum purpureum, 750 for Brachiaria mutica, 341 for Digitaria decumbens, 299 for Panicum maximum, 283 for Paspalum notatum, 269 for Cynodon dactylon, 41 for Melinis minutiflora and 29 for Hyparrhenia rufa. Nitrogenase activity varied considerably with season and was maximal during active vegetative growth of two of the grasses. Significant differences between Paspalum notatum ecotypes and cultivars. in Azotohacter paspali occurrence and nitrogen fixation, indicate the possibility of plant breeding to enhance nitrogen fixation in grass rhizospherc associations. Other research lines of agronomic importance are fertilizer effects. In intact soil plant cores with the Paspalum system 10 parts/10⁶ NH_4⁺J-N inhibited nitrogenase activity within 2 h and 10 parts/10⁶ NO^?₃-N within 4 h. but after 1 week these effects were negligible. In the field, nitrogenase activity on roots of P. purpureum and D. decumbens, assayed 2 weeks after top dressings of 20 kg N ha^?1 as NH₄NO₃. was not affected even after eight such dressings.     

Effect of seasonality and trophic group on energy acquisition in Amazonian fish

Abstract –  The influence of hydrologic cycle and trophic groups on the energy content of food was investigated for five fish species from a Central Amazonian floodplain area. Sampling was carried out monthly using gillnets of different mesh sizes immersed in water for 24 h. We examined the presence and absence of food in fish stomachs and those with food were analysed and their energy content determined. Amongst the trophic groups studied, the piscivores Acestrorhynchus falcirostris and Pygocentrus nattereri showed high numbers of empty stomachs throughout the sampling period and very high levels of energy density in their food, which may explain why they take food less frequently. On the other hand the invertivorous species Hemiodus sp. and Hoplosternum littorale and the herbivore Rhytiodus microlepis , need to take food very frequently. The energy of the piscivorous species' stomach contents was not significantly different during the hydrologic cycle, whereas the invertivore and herbivore varied significantly, showing a general tendency of high levels of energy during high waters.