Effects of winter flooding on phosphorus dynamics in rice fields

Limnology - Controlling phosphorous (P) loads from rice fields is important for the conservation of aquatic ecosystems, in part because P is relatively concentrated at its sources. Recently, winter...     

Protective effects of glutathione against lipid peroxidation in chronically iron-loaded mice

To elucidate the protective effects of glutathione against iron-induced peroxidative injury, changes in the hepatic glutathione metabolism were studied in chronically iron-loaded mice. When the diets of the mice were supplemented with carbonyl iron, iron deposition occurred primarily in the parenchymal cells of the liver. In addition, expiratory ethane production was elevated, suggesting an enhancement in lipid peroxidation. In iron-loaded mice, the total hepatic glutathione contents were higher (6.21 +/- 0.53 mumol/g wet wt.) than in control mice (4.61 +/- 0.31 mumol/g wet wt.), primarily due to an increase in the reduced glutathione contents. The value of oxidized glutathione was also higher (98.5 +/- 8.1 nmol/g wet wt.) than in the controls (60.8 +/- 9.5 nmol/g wet wt.), and the ratio of oxidized glutathione to total glutathione increased. The excretion rate of glutathione from the hepatocytes in iron-loaded mice also increased. These observations suggest that chronic iron-loading of mice stimulates lipid peroxidation and oxidation of glutathione and that peroxidized molecules may be catabolized using reduced glutathione.     

Na+ and K+ fluxes stimulated by Na+-coupled glucose transport: Evidence for a Ba2+-insensitive K+ efflux pathway in rabbit proximal tubules

Summary Addition of glucose or the nonmetabolizable analogue -methyl-d-glucoside to rabbit proximal tubules suspended in a glucoseand alanine-free buffer caused a sustained increase in intracellular Na⁺ content (+43±7 nmol · (mg protein)^–1) and a concomitant but larger decrease in K⁺ content (–72±11 nmol· (mg protein)^–1). A component of the net K⁺ efflux was Ba²⁺ insensitive, and was inhibited by high (1mm) but not low (10 m) concentrations of the diuretics, furosemide and bumetanide. The increase in intracellular Na⁺ content is consistent with the view that the increased rates of Na⁺ and water transport seen in the proximal tubule in the presence of glucose can be attributed (at least in part) to a stimulation of basolateral pump activity by an increased [Na⁺] _i .     

Biotransformation of germacrane-type sesquiterpenoids by Aspergillus niger

Three germacrane-type sesquiterpenoids, (+)-germacrone-4,5-epoxide, germacrone and (+)-curdione were biotransformed by Aspergillus niger to give hydroxylated guaiane-type sesquiterpenoids together with allylic alcohols and spirolactone.     

Association of Lps gene with natural resistance of mouse macrophages against Legionella pneumophila

We have cloned a 1.6-kb region of chromosomal DNA from Thermoplasma acidophilum into Escherichia coli using as a probe part of the Methanococcus vannielii fus-gene. The sequence of the clone was highly homologous to part of the corresponding Methanococcus vannielii gene. By chromosome walking, a 4.7-kb EcoRI fragment containing the complete gene was isolated. Nucleotide sequencing revealed an open reading frame of 2196 nucleotides. The deduced amino acid sequence contains the known peptide sequence around the ADP-ribosylation site of T. acidophilum elongation factor 2, which unequivocally confirms that the fus-gene has been cloned. The amino acid sequence was compared to that of hamster and E. coli, as well as to known archaebacterial EF-2 sequences.     

Comparison of plasma prostanoid levels in the human cord artery in normal and fetal distressed deliveries

Prostaglandin E2 (PGE2), thromboxane B2 (TXB2; as a stable metabolite of TXA2), prostaglandin F2 alpha (PGF2 alpha) and 6-keto-PGF1 alpha (as a stable end product of prostacyclin) have been measured by using specific radioimmunoassay in the plasma of the cord artery immediately after delivery before the cord was clamped. Plasma prostanoid concentrations in normal deliveries (n = 8, as controls) were 24.8 +/- 2.6 (PGE2), 246.8 +/- 37.0 (TXB2), 122.2 +/- 13.3 (PGF2 alpha) and 82.1 +/- 7.7 (6-keto-PGF1 alpha) respectively (pg/ml, mean +/- s.e). On the other hand, in fetal distressed deliveries showing continuous bradycardia (n = 6), they increased significantly to 275.4 +/- 20.1 (PGE2), 948.6 +/- 102.5 (TXB2), 218.0 +/- 21.4 (PGF2 alpha) and 1498.6 +/- 298.4 (6-keto-PGF1 alpha) respectively (pg/ml, mean +/- s.e, p less than 0.005). However, both PGF2 alpha/PGE2 and TXB2/6-keto-PGF1 alpha ratios declined significantly from 4.70 +/- 0.33 to 0.68 +/- 0.05 and from 3.07 +/- 0.37 to 0.68 +/- 0.12 respectively (mean +/- s.e, p less than 0.005) in the fetal distressed group compared with those of the controls. From these results, it may be concluded that the cord artery, which is known as the patent source for the production of PGE2 and prostacyclin, did exert a sufficiently strong reaction to overcome the undesirable haemodynamic changes to maintain the fetal well-being in utero.     

High-Resolution Proton Magnetic Resonance Analysis of Human Cerebrospinal Fluid

High-resolution proton magnetic resonance spectroscopy was used to analyze human cerebrospinal fluid obtained from patients with several neurological problems. The major metabolites measured included glucose, lactate, glutamine, citrate, inositol, acetate, creatine, creatinine, beta-hydroxybutyrate, alanine, and pyruvate. A drug vehicle, propylene glycol, was also measured. Alterations in the cerebrospinal fluid of these metabolites provided information concerning metabolism of the brain. Magnetic resonance spectroscopy offered a simple and rapid means of assessing these and other exogenous and endogenous compounds in diseases affecting the nervous system.     

The Eiken Latex test for detection of a cryptococcal antigen in cryptococcosis

A latex agglutination test for cryptococcal antigen, the Eiken Latex test (Eiken, Tokyo, Japan), was compared with a monoclonal antibody-based agglutination assay, Pastorex^® Cryptococcus (Diagnostics Pasteur, Marneur-la-Coquette, France). In a murine model of disseminated cryptococcosis, the kinetics of the antigen titers by the Eiken Latex were similar to those by the Pastorex^® Cryptococcus, but sensitivity was much higher. In HIV-negative patients with pulmonary cryptococcosis, a cryptococcal antigen was detected in 6 of 10 patients by the Eiken Latex test and in only 3 of those patients by the Pastorex^® Cryptococcus. The results indicate that the Eiken Latex is more sensitive for the detection of the cryptococcal antigen, even in non-disseminated cryptococcosis. The sensitivity and specificity of the Eiken Latex were examined using 195 sera from 25 patients with pulmonary cryptococcosis and 170 patients with non-cryptococcosis. The cutoff value of 1:8 showed a sensitivity of 76% (19/25) and a specificity of 98.9% (168/170).     

Organic-Solvent-Tolerant Bacterium Which Secretes Organic-Solvent-Stable Lipolytic Enzyme

A bacterial strain which could be grown in a medium containing organic solvents and which could secrete lipolytic enzyme was isolated. The stability of the lipolytic activity of the supernatant of the culture increased significantly in the presence of organic solvents such as toluene, cyclohexane, ethanol, and acetone.