Search

Abstract: We analyzed two disease model groups with rats infected by Japanese encephalitis virus (JEV), a 90-day group and a 180-day group after JEV infection. The time measured by the modified pole test showed that motor activities in these two groups were slower than those of age-matched control groups. Striatal dopamine (DA) levels were significantly decreased in all JEV-infected rats. Norepinephrine concentration in brain regions in the 180-day group was significantly decreased in the medulla oblongata and hypothalamus as compared with the control and 90-day group. Tyrosine hydroxylase-positive neurons were significantly decreased in both JEV-infected rat groups. These results suggest that DA decrease and pathological changes in JEV-infected model rats persist for a long time, at least up to 180 days, and this model will be useful for the evaluation of new anti-parkinsonian agents.

In monoculture, it is difficult to entirely avoid contamination by microorganisms. Generally there is some risk that a new species will suddenly erupt. On the other hand, in a heterogeneous ecosystem, this is prevented by the presence of other species. In space, the risk of outbreak can be transformed into an opportunity to find new cultivars by a kind of radiation breeding. Moreover, heterogeneous terrestrial ecosystems comprising useful plants can fulfill many other practical functions, not only in space but also in the home and work environment, as an advanced type of indoor greenery. Observations of heterogeneous ecosystems can make an enormous amount of data simultaneously available to numerous studies, a model familiar in astronomical observations. We have developed an experimental facility, a Multi-purpose Artificial Terrestrial Ecosystem (MATE), to collect time-series data indispensable in the development of computational models for complex systems. MATE consists of soil with a vast number of species of microorganisms and useful plants, the environmental conditions adapted to humans. MATE has been automatically operated by a PC since August 2, 1999. By analyzing slow-speed digital photography, we have determined several interesting rules to apply in the three-dimensional modeling of the dynamics of competitions amongst plants.

A continuous-time quantitative plant growth model is proposed. The model is implemented as a neural network, which is a three layers neural network and has mutual connections on the middle layer. The neural network is derived from Lotka-Volterra equations which describe mechanism of physiological interference between organs. The plant growth model includes the specific organ growth models which are represented by units which have same functions as neurons. It is shown with computer simulation that solutions of the plant growth model implemented as a neural network are approximated to that of Lotka-Volterra equations. The relation between the Lotka-Volterra system and neural networks is discussed and an algorithm to estimate unknown parameters in the models is proposed.

Global optimization algorithms are required for optimal control of complex systems such as plant growth and crop yield. Processes for global optimization, selfprogramming and the determination of accurate fitness (evaluation) functions are indispensable to modeling in the strong AI and strong A-Life projects. The modeling of complex processes like consciousness and evolution will be applied towards the development of global optimization algorithms. To date several models of the microscopic mechanisms involved in brain function have been proposed that are based on quantum dynamics. However biological systems comprise a hierarchy from the microscopic to the macroscopic level. Here we employ both quantum dynamics and a systems theoretical approach based on techniques derived from the modeling of consciousness and evolution to propose a global optimization algorithm that can avoid locally optimal states of non-linear functions.

Knowledge acquisition systems for image enhancement procedures have been developed using Java. Based on genetic algorithms (GAs), the systems can optimize procedures for enhancing target components in the digital images of plants in fields. Using rough objective images given by users as a standard image for evaluating fitness, it can provide appropriate filtering operations and their parameters. To improve convergence, interactive selection, which selects a promising individual by human intention instead of the fitness function, has been introduced. Consequently, the combination of the fitness function and interactive selection has contributed to rapid convergence of the processing.

The effect of activin (activin A/EDF) on osteoclast formation was investigated. In mouse bone marrow cell cultures, activin enhanced the formation of tartrate-resistant acid phosphatase (TRACP)-positive multinucleated cells (MNC) in a dose-dependent manner, either in the presence or absence of 1,25-(OH)2D3or PTH. In organ cultures of neonatal mouse calvaria, activin also enhanced the generation of TRACP-positive giant cells in the endosteal periosteum and increased the TRACP staining of whole calvaria, but did not exhibit bone resorbing activity. These results indicate that activin stimulates the formation of osteoclasts, but not osteoclast activation. Activin is produced by bone marrow cells and might be involved in the local process of osteoclast differentiation.

In rat basophilic leukemia cells (2 H3-RBL) stimulated with the calcium ionophore A 23187, a rapid build-up of PAF-acether was observed within 5 minutes. Thereafter, a slow and complete catabolism was observed within the next 55 minutes. Accumulation of PAF-acether required calcium in the medium and was increased in the presence of acetyl-CoA. Phenyl methyl sulfonyl fluoride, a serine hydrolase inhibitor active on 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetyl hydrolase also produced an increased accumulation of PAF-acether in ionophore-stimulated cells. Quinacrine, a non specific inhibitor of phospholipase A2 impaired PAF-acether formation in a dose-dependent manner. The time-course of PAF-acether formation was compared with the ionophore-induced release of arachidonic acid from these cells.

This study aimed to investigate whether the consecutive administration of methotrexate affects 5-hydroxytryptamine (5-HT) synthesis in the rat small intestine. Rats received methotrexate at a dose of 12.5 mg/kg intraperitoneally on 4 consecutive days. NG-nitro-L-arginine methyl ester (L-NAME) was given subcutaneously to inhibit nitric oxide (NO) synthase. Methotrexate moderately altered 5-HT synthesis, whereas the combined administration of methotrexate and L-NAME significantly changed 5-HT synthesis in the rat ileal tissue. These results suggest that endogenous NO has an antagonistic role in the induction of 5-HT synthesis in rats following the consecutive administration of methotrexate., (© 2020 S. Karger AG, Basel.)