Upregulation of metallothionein-I mRNA expression in a rodent model for amyotrophic lateral sclerosis

Metallothionein (MT) mRNA expression was investigated in a rodent model (G93A SOD1 transgenic mouse) for a lethal motor neuron disease, amyotrophic lateral sclerosis (ALS). In 8-wk-old mice that did not yet exhibit motor paralysis, MT-I mRNA expression was already significantly upregulated in the region of the spinal cord responsible for motor paralysis. The expression of another isoform, MT-III, was not changed. In the cerebellum, which is not responsible for motor paralysis in ALS, neither the expression profiles of MT-I nor MT-III were altered. In 16-wk-old mice exhibiting motor paralysis, the expression of MT-I mRNA remained upregulated and the MT-III level tended to be elevated. Although no significant differences were found in the levels of both isoforms in the liver or kidney of 8-wk-old mice, the MT-I mRNA expression level was significantly upregulated in the kidney and liver of 16-wk-old mice. These results indicated that the MT-I isoform, but not the MT-III isoform, is associated with motor neuron death in ALS and suggested that the disease might be a systemic disorder to which the spinal cord is particularly susceptible.     

Influence of temperature and soil nitrogen and phosphorus availabilities on fine-root productivity in tropical rainforests on Mount Kinabalu,Borneo

We investigated how temperature and nutrient availability regulate fine-root productivity in nine tropical rainforest ecosystems on two altitudinal gradients with contrasting soil phosphorus (P) availabilities on Mount Kinabalu, Borneo. We measured the productivity and the nutrient contents of fine roots, and analyzed the relationships between fine-root parameters and environmental factors. The fine-root net primary productivity (NPP), total NPP, and ratio of fine-root NPP to total NPP differed greatly among the sites, ranging from 72 to 228 (g m^?2 year^?1), 281–2240 (g m^?2 year^?1), and 0.06–0.30, respectively. A multiple-regression analysis suggested a positive effect of P availability on total NPP, whereas fine-root NPP was positively correlated with mean annual temperature and with P and negatively correlated with N. The biomass and longevity of fine roots increased in response to the impoverishment of soil P. The carbon (C) to P ratio (C/P) of fine roots was significantly and positively correlated with the P-use efficiency of above-ground litter production, indicating that tropical rainforest trees dilute P in fine roots to maintain the C allocation ratio to these roots. We highlighted the mechanisms regulating the fine-root productivity of tropical rainforest ecosystems in relation to the magnitude of nutrient deficiency. The trees showed C-conservation mechanisms rather than C investment as responses to decreasing soil P availability, which demonstrates that the below-ground systems at these sites are strongly limited by P, similar to the above-ground systems.     

Induction of Tension Wood in GA3-treated Branches of the Weeping Type of Japanese Cherry, Prunus spachiana

GA₃ prevented the bending of branches in the weeping type ofJapanese cherry, Prunus spachiana. Eccentric growth of GA₃-treatedbranches was observed. In the xylem on the upper side of suchbranches the presence of gelatin fibers, which stained stronglywith fast green, was demonstrated. Moreover, a less dense distributionof vessels and a steeper angle of cellulose microfibrils inthe secondary walls of fibers were also observed on this side.Similar features were noted in the xylem of the branches ofcherry trees of the upright type, but they were not found inGA₃-untreated control branches of trees of the weeping type.These results suggest that GA₃ induces tension wood on the upperside of branches of Prunus spachiana of the weeping type, sothat the branches become to grow upwards, resembling branchesof the upright type. (Received December 19, 1994; Accepted May 29, 1995)     

Intraspecies variations of red cell enzymes and hemoglobin inMacaca irus

Blood samples ofMacaca irus imported from Cambodia and the Philippines were examined by starch gel electrophoresis for red cell acid phosphatase, phosphoglucomutase, and hemoglobin variations.Two different types, each showing two and three zones with acid phosphatase activity, were observed in 172 cynomolgus monkeys. Variant (less common) type was detected in only eight of 113 in the Cambodian group.Individual differences in the distribution of phosphoglucomutase isoenzymes were also found in the monkey samples. Five different types were distinguished in 145 samples examined, but no possible explanation for genetic control can be given for the observed patterns.In addition to the usual hemoglobin found in all the hemolysates, fastmigrating hemoglobin components were demonstrated in 36% of 172 samples. A striking difference in the distribution of the hemoglobin types was found between the Cambodian and the Philippine groups.The obtained results probably indicate the existence of strong geographical effects on protein polymorphisms in cynomolgus monkey.     

Application of matrix-assisted laser desorption ionization time-of-flight mass spectrometry with delayed ion extraction to ganglioside analyses

Various monosialo- and disialo-gangliosides and their derivativeswere examined by delayed ion extraction matrix-assisted laserdesorption ionization time-of-flight mass spectrometry (DE MALDI-TOFMS) in the reflector mode with     

In vivo oxidation of reduced nicotinamide-adenine dinucleotide phosphate by paraquat and diquat in rat lung.

Intravenous injection of rats with 156 mumol/kg of paraquat or 140 mumol/kg of diquat produced, within 60 min, a sharp drop in the ratios of NADPH to NADP in lung. The effect persisted for a time period of at least 24 h. Exposure to 100% oxygen enhanced the toxicity of both compounds without substantially amplifying changes in the NADPH/NADP ratio. Lungs retained the capability to synthesize adenine nucleotides de novo. Electron microscopic studies showed that both paraquat and diquat damage type I alveolar cells, but only paraquat produces type II cell lesions. Although bipyridylium herbicides produce acute oxidation of NADPH in vivo, there seems not to exist a straightforward relationship between this event and cell damage.