Structural and functional basis for GABAA receptor heterogeneity

When gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in vertebrate brain, binds to its receptor it activates a chloride channel. Neurotransmitter action at the GABAA receptor is potentiated by both benzodiazepines and barbiturates which are therapeutically useful drugs (reviewed in ref. 1). There is strong evidence that this receptor is heterogeneous. We have previously isolated complementary DNAs encoding an alpha- and a beta-subunit and shown that both are needed for expression of a functional GABAA receptor. We have now isolated cDNAs encoding two additional GABAA receptor alpha-subunits, confirming the heterogeneous nature of the receptor/chloride channel complex and demonstrating a molecular basis for it. These alpha-subunits are differentially expressed within the CNS and produce, when expressed with the beta-subunit in Xenopus oocytes, receptor subtypes which can be distinguished by their apparent sensitivity to GABA. Highly homologous receptor subtypes which differ functionally seem to be a common feature of brain receptors.     

Antitumor activity of the Isodon diterpenoids: structural requirements for the activity.

A significant antitumor activity of oridonin (1) and lasiokaurin (2), the kaurene-type diterpenoids of Isodon species, was shown by their i.p. injection to the test mice inoculated by Ehrlich ascites carcinoma. Enmein (8), compounds 9 and 3 were also active under larger dose. Subsequently, the relationship between their chemical structure and antitumor activity was investigated, and the activity of oridonin (1) and lasiokaurin (2) was rationalized in terms of their structural feature.     

Implementation of 3-Valued Paraconsistent Logic Programming Towards Decision Making System of Agents

Due to the rapid development of applications of artificial intelligence and robotics in recent years, the necessity of reasoning and decision making with uncertain and inaccurate information is increasing. Since robots in the real world are always exposed to behavioral inaccuracies and uncertainty arising from recognition methods, they may occasionally encounter contradictory facts during reasoning on action decision.Paraconsistent logic programming is promising to make appropriate action decisions even when an agent is exposed to such uncertain information or contradictory facts, but there has been no implementation of this programming to the best of our knowledge. We propose a resolution algorithm for the 3-valued paraconsistent logic programming system QMPT0 and its implementation on SWI-Prolog. We also describe an application of the 3-valued paraconsistent logic programming regarding agent decision making.     

Comparison of X-prolyl dipeptidyl-aminopeptidase activity in human cerebrospinal fluid with that in serum

Summary X-Prolyl dipeptidyl-aminopeptidase activities in cerebrospinal fluid and serum from the same patients without neurological diseases, undergoing surgery under lumbar anesthesia, were assayed fluorometrically with a newly synthesized fluorogenic substrate, 7-glycylproline-4-methylcoumarinamide; the values were 129.1±19.5 nmoles/min/1 and 54.17±3.11 moles/min/1 (mean±SEM, n=23), respectively, and there was no correlation between both activities (r=0.0894).     

Mitochondrial association of alpha-synuclein causes oxidative stress

α-Synuclein is a neuron-specific protein that contributes to the pathology of Parkinson’s disease via mitochondria-related mechanisms. The present study investigated possible interaction of α-synuclein with mitochondria and consequences of such interaction. Using SHSY cells overexpressing α-synuclein A53T mutant or wild-type, as well as isolated rat brain mitochondria, the present study shows that α-synuclein localizes at the mitochondrial membrane. In both SHSY cells and isolated mitochondria, interaction of α-synuclein with mitochondria causes release of cytochrome c, increase of mitochondrial calcium and nitric oxide, and oxidative modification of mitochondrial components. These findings suggest a pivotal role for mitochondria in oxidative stress and apoptosis induced by α-synuclein. Received 27 December 2007; received after revision 7 February 2008; accepted 8 February 2008     

Membrane fractions of rabbit granulocytes. 1. The presence of ouabain-sensitive ATPase and the electrophoretic patterns.

In one or two membrane fractions isolated from the homogenate of casein-induced rabbit granulocytes ouabain-sensitive ATPase activity was found definitely. Electrophoretic patterns of these membrane fractions showed no significant differences in staining for carbohydrate and protein.     

Specific reaction of aloe extract with serum proteins of various animals

Summary We found that aloe extract contains a lectin-like substance which reacts with serum proteins of various animals. Furthermore, in human serum 2 proteins,a ₂-macroglobulin anda ₁-antitrypsin, were shown to be reactive with aloe extract.