Toxicity Testing of Senna occidentalis Seed in Rabbits

The effect was investigated of administering ground Senna occidentalis seeds to rabbits in different concentrations (1%, 2%, 3% and 4%) in the ration. The experiment lasted 30 days and the toxic effects of the plant were evaluated on the basis of weight gain, histopathological, biochemical and morphometric parameters, as well as histochemistry and electron microscopy. Animals that received the ration containing 4% ground S. occidentalis seeds gained less weight (p<0.05) and died in the third week. Histopathology revealed that the heart and liver were the main organs affected, with myocardial necrosis and centrolobular degeneration. There was a reduction in cytochrome oxidase activity in the glycogenolytic fibres, together with muscle atrophy, confirmed by the morphometric studies. Electron microscopy of the liver cells revealed dilated mitochondria, with destruction of the internal cristae.     

Evaluation of a protease activation mutant of Sendai virus as a potent live vaccine.

A protease activation mutant of Sendai virus, TR-5, was investigated as a candidate for a live vaccine. Vaccination with TR-5 which had been activated by chymotrypsin beforehand (active TR-5) elicited protective immunity against otherwise lethal challenge infection with wild-type Sendai virus in DBA/2, C3H and ICR strains of mice. Less of the active TR-5 was required to confer protection on mice compared with an ordinary ether-inactivated Sendai virus vaccine (split vaccine). The protective immunity elicited by TR-5 lasted longer and the booster effect was more prominent compared to the split vaccine. No seroconversion was observed with contact mice when housed in a cage with mice vaccinated with the active TR-5. The overall results show that the active TR-5 is an effective and safe live vaccine of Sendai virus in mice.     

Conserved role of nanos proteins in germ cell development

In Drosophila, maternally supplied Nanos functions in the migration of primordial germ cells (PGCs) into the gonad; in mice, zygotic genes are involved instead. We report the cloning and the functional analyses of nanos2 and nanos3 in mice. These genes are differentially expressed in mouse PGCs. nanos2 is predominantly expressed in male germ cells, and the elimination of this gene results in a complete loss of spermatogonia. However, nanos3 is found in migrating PGCs, and the elimination of this factor results in the complete loss of germ cells in both sexes. Hence, although mice and flies differ in their mechanisms for germ cell specification, there seems to be conserved function for nanos proteins among invertebrates and vertebrates.     

Human exposure to mercury due to goldmining in the Tapajos River basin,Amazon, Brazil: Speciation of mercury in human hair,blood and urine

To obtain the basic information on human exposure to mercury (Hg) due to gold mining activities in Amazon, total mercury (T-Hg) and methylmercury (MeI Ig) were determined for human hair, blood and/or urine samples collected from populations living in gold mining area and fishing villages upstream of the Tapajos River basin. Abnormally high levels of T-Hg were observed in hair and blood from all fishing villages investigated and more than 90% of T-Hg was in the form of MeHg in both samples, whereas in goldrnining area the value were much lower and the %MeHg values varied widely (20–100%) with individuals even in blood samples. Urine from gold shop workers contained Hg mostly in inorganic form at 165μg/g creatinine on the average, with the range of 20 to 450μg/g creatinine. A good correlation between Hg in hair and blood was found in fishing villages and the ratios of hair Hg to blood Hg were very close to 250, generally established for MeHg. T-Hg and inorganic Hg levels in urine from gold shop workers were also significantly correlated with inorganic Hg in blood.     

Alkaloidal components in the poisonous plant,Ipomoea carnea (Convolvulaceae)

Natural intoxication of livestock by the ingestion of Ipomoea carnea (Convolvulaceae) sometimes occurs in tropical regions of the world. Polyhydroxylated alkaloids were isolated from the leaves, flowers, and seeds of the poisonous plant and characterized. Chromatographic separation of the leaf extract resulted in the isolation of swainsonine (1), 2-epi-lentiginosine (2), calystegines B(1) (3), B(2) (4), B(3) (5), and C(1) (6), and N-methyl-trans-4-hydroxy-l-proline (7). The contents of 1 in the fresh leaves and flowers were 0.0029 and 0.0028%, respectively, whereas the contents of 1, 3, and 4 in the seeds were approximately 10 times higher than those in the leaves and flowers. Alkaloids 3, 4, and 6 showed a potent inhibitory activity toward rat lysosomal beta-glucosidase, with IC(50) values of 2.1, 0.75, and 0.84 microM, respectively, and alkaloid 5 was a moderate inhibitor of alpha- and beta-mannosidases. Although alkaloid 1 is known as a powerful inhibitor of lysosomal alpha-mannosidase (IC(50) = 0.02 microM), alkaloid 2, which has been thought to be an intermediate in the biosynthesis of 1, was also a potent inhibitor of alpha-mannosidase with an IC(50) value of 4.6 microM.     

Quantification of soil surface evaporation under micro-scale advection in drip-irrigated fields

The objective of this study is to quantify soil surface evaporation under micro-scale advection in drip-irrigated fields. A numerical model for estimating soil surface evaporation under micro-scale advection, assuming drip-irrigated fields, is introduced. Results indicate that the soil surface evaporation changes spatially. Soil surface evaporation at the upwind edge of wet soil portions adjacent to dry soil portions increased abruptly. On the other hand, soil surface evaporation at the upwind edge of dry soil portions adjacent to wet soil portions decreased, and condensation was observed. These phenomena were considered to be due to airflows between differing climates. To verify the accuracy of the model, an experiment using a wind tunnel was conducted. The simulated soil surface evaporation results from the model were consistent with the experimental data. The numerical model introduced here is an effective way to quantify soil surface evaporation under micro-advective conditions.     

Observation and simulation of thermal environment in a paddy field

This research studied thermal environment in paddy field which the main objective to evaluate it when the water was present in the field by means of observation and simulation. Heat exchange in soil and water, plant and atmosphere were calculated using a two-layer resistance model. The atmospheric boundary layers-thermal, humidity and wind velocity-were assumed horizontally uniform and were arranged in one-dimensional equations. The observed paddy field was located at Kyushu University Experimental Farm in Fukuoka, Japan. In the simulation, fix boundary conditions of wind velocity and humidity, and fluctuating boundary condition of temperature at 100 m height were used over the paddy field with the presence of 5 cm depth of water layer. The simulation was successful in estimating radiation, dissipation of heat fluxes, mechanism of atmospheric thermal changes and the temperature of leaf, air, and water. The results show that most of the available energy dissipates into latent heat, and less into sensible heat.     

Impact of aquatic plants on entrainment phenomena based on wind-induced flow in a closed density stratified water area

It has recently been proposed that water purification could be performed using aquatic plants, since they absorb nutrient salts. The behavior of a substance in a closed water area is affected by turbulent flows from wind-induced flow, which is a mechanical disturbance, and convective flow, which is a thermal disturbance. In a closed density stratified water area, wind-induced flow gives rise to the entrainment phenomenon at the density interface. This phenomenon, which is based on mixing between the upper and lower water layers, lowers the density interface and so affects the water quality. We experimentally investigated the effect of aquatic plants on the turbulent flow from a mechanical disturbance in the closed water area. Results indicated that the presence of floating and submerged plants had a significant effect on the scale of the turbulent entrainment, and that the entrainment velocity depended on the overall Richardson number to the power of –3/2.