Effect of Hydrotropism on Root System Development in Soybean ( Glycine max): Growth Experiments and a Model Simulation

To observe root system development, soybean plants (Glycine max) were grown in root boxes that were set horizontally to reduce the effect of gravity. Along with the root system development, the two-dimensional distribution of soil water content in the root boxes was measured continuously by the time domain reflectometry (TDR) method. Root system development and its morphological architecture were strongly affected by the positions of the water supply. It is suggested that root hydrotropism plays the dominant role in root system development. In addition to root hydrotropism, the importance of root compensatory growth is suggested. A combined model of root system development and soil water flow considering root hydrotropism and compensatory growth was used to simulate root system development and soil water flow. The morphological architecture of root systems and the distribution of soil water content obtained in the experiment were successfully explained by the model simulation. These results confirmed that root hydrotropism and compensatory growth are dominant factors in root system development under a reduced effect of gravity. The validity of the model was confirmed, and its applications for various purposes were suggested.     

A combined staining method for argyrophilic nucleolar organizer regions and for glial fibrillary acidic protein in astrocytes of human brain

Summary Different protocols are described for the combined staining method by which argyrophilic nucleolar organizer region sites can be evaluated in human astrocytes that are immunoreactive for glial fibrillary acidic protein. Among the four protocols studied, the following method was superior to others in terms of unambiguous visualization of the regions in glial fibrillary acidic protein-positive astrocytes; the first step was immunostaining for the protein with a blue colour reaction of alkaline phosphatase, followed by sequential colloidal silver staining for the regions. By this double staining method, we have demonstrated that the reactive astrocytes found in white matter around the metastatic lesion of carcinoma and the infarction, contain more argyrophilic nucleolar organizer regions in terms of the count as well as the area than glial fibrillary acidic protein-positive astrocytes present in the white matter of the normal brain. In conclusion, the double staining may provide valuable information on the cellular activity of astroglia when performed on routine formalin-fixed paraffin sections of the human brain.     

Ring neural network qua a generator of rhythmic oscillation with period control mechanism

For the ring neural network to function as a generator of rhythmic oscillation, mechanisms are required by which rhythmic oscillation is generated and maintained and then its period controlled. This paper demonstrates by simulation that those mechanisms can be actualized by employing a synaptic modification algorithm and by applying inputs from the outside to excitatory and inhibitory cells. When the constants in the synaptic modification algorithm are fixed, it is possible to select two modes, that is, the modification mode and the non-modification mode, using the excitatory input level to excitatory cells alone. This property solves the problem of the re-modification caused by the dispersion of AIDs (average impulse densities) with the application of the excitatory synchronous input to inhibitory cells.     

Lectin activity of Bacillus thuringiensis parasporal inclusion proteins

Parasporal inclusion proteins from a total of 151 Bacillus thuringiensis strains, consisting of 139 Japanese isolates and the type strains of 12 H serovars, were screened for haemagglutination (HA) activity against sheep erythrocytes. Of 58 B. thuringiensis strains with HA activity, nine strains exhibited high activity and the remaining 49 strains were moderately active. The strains with high HA activity were derived from phylloplanes and soils of five geographically different localities, and belonged to H serovars kurstaki and other undefined serotype(s). The HA activities in the four selected strains were generated only when alkali-solubilised parasporal inclusion proteins were proteolytically processed. Furthermore, the lectin activity of the four strains was strongly inhibited by preincubation with N-acetylgalactosamine. The lectin-producing B. thuringiensis strains were heterogeneous in other biological activities of parasporal inclusions: insecticidal activity and cytocidal action on human leukaemia T cells.     

Distribution of retinol-binding protein in the human digestive tract.

By employing polyclonal antibodies for retinol-binding protein (RBP), its distribution in the human pancreas and digestive tract mucosa was compared with those of transthyretin (TTR) and various peptide hormones. The materials used included surgically removed pancreas, esophagus, stomach, small and large intestines. Paraffin sections were stained by the indirect immunoenzyme method. The results indicate that RBP-containing cells are found in the pancreas and the gastrointestinal mucosa, but most frequently in the gastric antrum and duodenum. In the pancreas, RBP-containing cells are found in the islets and among acinar and ductal epithelial cells, and consistently stain for chromogranin A. RBP-containing cells in the gastrointestinal mucosa showed typical features of endocrine cells and also stained for chromogranin A. The distribution of TTR in these tissue sites resembled that of RBP, but the immunoreactive intensities of both peptides altered independently. Comparison of the distribution of RBP, TTR, and various gastrointestinal peptide hormones revealed that the distribution of RBP coincided with none of the other peptides, although some of the RBP-containing cells stained for most of the peptides examined and vice versa. These results suggest that RBP may be a consistent component of gastrointestinal endocrine cells.