Effect of phosphorus on Azolla and its utilization in rice culture in Niger

The trials to use Azolla as a green manure for rice culture were made in the Niger basin.Azolla pinnata (Niger isolate) was used for the experiments. The effect of phosphorus on the growth and N₂-fixation was examined in the field and in the laboratory. The growth rate and N content were maximum with P 3.1 ppm culture solution under laboratory conditions. The threshold P content for the growth was 0.5–0.6% in the dry matter. Maximum N content was 4.1% in the laboratory culture. In the field culture, the effect of P fertilizer on the growth and N yield of Azolla was tested. The split application of 6.5 kg P ha⁻¹ per 13 days was most effective in stimulating the growth of Azolla. One kg of P as triple superphosphate produced 3.66 kg N in the Azolla. Maximum growth rate and N content in the field trials was 4.3 days (doubling time) and 2.3%, respectively. The lower productivity in the field in comparison with the laboratory culture was considered to be due to higher temperature and light intensity. the growth of Azolla was suppressed in the hot season in the Niger basin. The growth rate and N content were reduced during the high temperature period over 30°C on an average. The effect of inoculation of Azolla on rice yield was tested in the field experiment. The grain yield was increased 27% by Azolla incolation over the treatment without Azolla inoculation in — N fertilizer treatments. While the growth of Azolla with rice plants did not attain saturated density (1.8 kg fresh weight m⁻²), the effect on the grain yield was comparable to 40 kg N ha⁻¹ as urea.     

Sonolysis of concentrated aqueous solutions of nonvolatile solutes: spin-trapping evidence for free radicals formed by pyrolysis

The sonolysis of argon-saturated aqueous solutions of sodium acetate, sodium propionate, amino acids, and sugars was investigated by ESR and spin trapping over a large range of concentrations. The spin trap 3,5-dibromo-2,6-dideutero-4-nitrosobenzene sulfonate was used to examine the possibility of detecting new radicals specifically generated in the high temperature zones surrounding the collapsing cavitation bubbles. At lower concentrations of these solutes, no evidence for specific new radicals formed in the high temperature regions induced by cavitation could be found, and only radicals formed by hydroxyl radical and hydrogen atom abstraction reactions could be detected. These were identified by comparison with the radicals produced by uv photolysis in the presence of hydrogen peroxide. However, at higher concentrations, new radicals (typically methyl radicals) formed in the high temperature interfacial regions induced by cavitation were found for sodium acetate, sodium propionate, amino acids, and sugars (D-mannose, D-glucose, 2-deoxy-D-ribose). These results indicate that pyrolysis radicals can be detected when the nonvolatile solutes are present at high concentrations in the interfacial regions of the cavitation bubbles.     

Anaerobic induction of trimethylamine N-oxide reductase and cytochromes by dimethyl sulfoxide inEscherichia coli

Reduction of trimethylamine N-oxide is catalyzed by at least two enzymes inEscherichia coli: trimethylamine N-oxide reductase, which is anaerobically induced by trimethylamine N-oxide, and the constitutive enzyme dimethyl sulfoxide reductase. In this study, an increase in the specific activity of trimethylamine N-oxide reduction was observed in the anaerobic culture with dimethyl sulfoxide, but the specific activity of dimethyl sulfoxide reduction was not changed. The inducible enzyme trimethylamine N-oxide reductase was found in this culture. A marked expression of the structural genetorA for trimethylamine N-oxide reductase was also observed in atorA-lacZ gene fusion strain under anaerobic conditions with either trimethylamine N-oxide or dimethyl sulfoxide.l-Methionine sulfoxide and the N-oxides of adenosine, picolines, and nicotinamide slightly repressed expression of the gene. Membrane-boundb- andc-type cytochromes involved in the trimethylamine N-oxide reduction were also produced in a wild-type strain grown anaerobically with dimethyl sulfoxide. But thec-type cytochrome was not produced in thetorA-lacZ strain grown anaerobically with trimethylamine N-oxide or dimethyl sulfoxide; this suggests that there is a correlation between the expression oftorA and the synthesis of the cytochrome.     

Shortening of the period of the circadian rhythm by a K+ channel blocker, tetraethylammonium, in the duckweed Lemna gibba G3

The period of the circadian rhythm of uptake of K+ by Lemna gibba strain G3 (duckweed), cultured in a flow medium, was shortened by continuous application of 0.5 mM tetraethylammonium chloride (TEA), which functions as a K+ channel blocker in both animal and plant cells. Other quaternary ammonium ions shortened the period of the rhythm in direct proportion to their ability to block K+ channels in cells of the nervous system. Ca2+ appears to be specific in its ability to antagonize this action of TEA and of its analogues.     

Relationships in actions of indoleacetic acid, benzyladenine and abscisic acid in ethylene production

The relationships between IAA and ABA, and between BA and ABAin their effects on ethylene production were examined with etiolatedmungbean hypocotyl segments. When ABA and IAA were simultaneouslyapplied to the tissues, ABA inhibited IAA-induced ethylene productionand the degree of inhibition was solely determined by the ABAconcentrations. Increasing concentrations of BA did not affectABA inhibition. Low concentrations of ABA slightly increasedendogenous ethylene production. When ABA and BA were appliedtogether in the presence of IAA, the degree of ABA inhibitionwas again determined by the ABA concentrations regardless ofthe BA concentrations. BA did not recover ABA inhibition andABA did not inhibit the stimulative effect of BA on both endogenousand IAA-induced ethylene production. Almost the same resultswere obtained with ABA and BA pretreatment of the tissues. Thisindicates that in the processes of IAA-induced ethylene production,IAA and ABA act in series, but that the actions at their respectivesites are independent. ¹ This research was partly supported by grants from the Ministryof Education (C-956037) and the Ministry of Agriculture (49–1330)of Japan, and by the Asahi Press. (Received June 14, 1975; )     

Schistosoma japonicum: Immunopathology of nephritis in Macaca fascicularis

Macaca monkeys experimentally infected with Schistosoma japonicum developed a chronic progressive kidney lesion characterized by an increase of mesangial matrix, local glomerular hypercellularity, and local thickening of glomerular basement membrane. Immunofluorescence studies revealed the localization of IgG, IgM, IgA, and IgE immunoglobulins mostly in the mesangial area of the glomeruli accompanied by the deposition of Schistosoma antigens. By electron microscopy, in addition to the local thickening of the glomerular basement membrane, dense homogeneous deposits and those with moth-eaten appearance were detected in the mesangial matrix. These findings suggest that worms in the bloodstream continuously release antigenic materials that stimulate host's antibody response belonging to various immunoglobulin classes including IgE. The produced antibodies and antigens would form immune complexes that deposited in the glomeruli. The increased vascular permeability caused by antigen-IgE antibody interaction may play an important role in the deposition of immune complexes and in the rapid development of kidney injury.