ABSTRACT
We present the MOlecular NETwork (MONET) ontology as a model to integrate data from different networks that govern cell function. To achieve this, different existing ontologies were analyzed and an integrated ontology was built in a way to make it possible to share and reuse knowledge, support interoperability between systems, and also allow the formulation of hypotheses through inferences. By studying the cell as an entity of a myriad of elements and networks of interactions, we aim to offer a means to understand the large-scale characteristics responsible for the behavior of the cell and to enable new biological insights.
Subject(s)
Humans , Animals , Algorithms , Cell Physiological Phenomena , Models, Biological , Databases as Topic , Microarray Analysis/methods , Computer SimulationABSTRACT
Cerebral ischemia causes cell death of vulnerable neurons in mammalian brain. Wistar adult rats (male and female, weighing 180-280 g) were submitted to 2 min, 10 min, or to 2 and 10 min (separated by a 24-h interval) of transient forebrain ischemia by the four-vessel occlusion method. Animals subjected to the longer ischemic episodes had massive necrosis of pyramidal CA1 cells of the hippocampus, while animals receiving double ischemia (2 + 10 min) showed neuronal tolerance to the ischemic insult. ATP-diphosphohydrolase activity from hippocampal synaptosomes was assayed in these three groups (N = 6 animals/group) under two conditions: no reperfusion and 5-min of reperfusion. The control values for ATPase and ADPase activities were 144.7 +/- 18.8 and 60.6 +/- 5.24 nmol Pi min-1 mg protein-1, respectively. The 10-min group without reperfusion showed an enhancement of approximately 20 for ATPase and ADPase activities. In reperfused rats, only the 2-min group had a 20 increase in both enzymatic activities. We suggest that modulation of ATP-diphosphohydrolase activity might be involved in molecular events that follow both ischemia and reperfusion.
Subject(s)
Animals , Male , Female , Rats , Apyrase , Ischemic Attack, Transient/enzymology , Hippocampus , Synaptosomes , Adenosine Triphosphatases , Rats, Wistar , Reperfusion , Time FactorsABSTRACT
ATP diphosphohydrolase (EC 3.6.1.5; apyrase) is an enzyme that can promote ATP and ADP hydrolysis to AMP plus inorganic phosphate and depends on divalent cations such as Ca2+ or Mg2+. In previous papers we described this enzyme in the synaptosomal fraction from the central and peripheral nervous system. The present report examines whether cadmium acetate could affect the in vitro activity of the enzyme in the synaptosomal fraction from the cerebral cortex of adult male Wistar rats. Cadmium (Cd2+), a heavy metal with neurotoxic effects, inhibited the enzyme in a concentration-dependent manner. All concentrations tested (0.05-1.0 mM) significantly inhibited the hydrolysis of both substrates (ATP and ADP), with the exception of 0.05 mM on ATP hydrolysis. The kinetic data indicate a noncompetitive inhibition between the cations Cd2+ and Ca2+.