Susceptibility of Legionella pneumophila grown extracellularly and in human monocytes to indole-3-propionic acid.

Indole-3-propionic acid (IPA), a phytohormone derivative, is a potent inhibitor of growth of Legionella pneumophila cultivated extracellularly in a chemically defined hypotonic medium and intracellularly in human monocytes. The inhibitory activity turns into bactericidal activity with increasing concentrations. The susceptibility of the microorganism to IPA was more evident in "fast-growing" cultures (under conditions of vigorous shaking) than in static cultures growing under an atmosphere of 5% CO2-95% air, which resulted in a decreased growth rate.

Purification and characterization of uridine and thymidine phosphorylase from Lactobacillus casei.

Uridine and thymidine phosphorylases have been purified to homogeneity from crude extracts of Lactobacillus casei. Both enzymes had an apparent molecular mass of about 80 kDa. Uridine phosphorylase consisted of four identical subunits while thymidine phosphorylase was composed of two identical ones.

Phytohormones as specific inhibitors of Legionella pneumophila growth.

Legionellae have been found to be highly susceptible to a variety of biological products, which increases the difficulty of growing these microorganisms. We developed a hypotonic medium in which Legionella pneumophila and other legionellae grow well and multiply rapidly from small inocula. Several amino acids, mainly nonessential ones, inhibited the growth of legionellae at high concentrations (200-1,000 micrograms/ml).

Congenital isolated folic acid malabsorption.

We report a case of congenital isolated malabsorption of folic acid, the first in a boy. Only seven previous cases have been reported, and we discuss two aspects--namely, the tendency to infection, with evidence of impairment of both cellular and humoral immunity, and the absence of neurological disturbances.

Active extrusion of potassium in the yeast Saccharomyces cerevisiae induced by low concentrations of trifluoperazine.

Trifluoperazine (TFP), the antipsychotic drug, induces substantial K+ efflux, membrane hyperpolarization and inhibition of H+-ATPase in the yeast Saccharomyces cerevisiae. Investigations on the mechanism of these effects revealed two different processes observed at different incubation conditions. At an acidic pH of 4.

The effect of growth temperature on the thermotropic behavior of the membranes of a thermophilic Bacillus. Composition-structure-function relationships.

The following study was carried out with the aim of widening our understanding of the thermoadaptive mechanisms of the membrane of thermophiles, using Bacillus stearothermophilus var. nondiastaticus as test-organism. The phospholipids and their acyl chain composition of this Bacillus studied in relation to the physical properties of its membrane from bacteria grown at various temperatures.

Mechanism of stimulation of Ca2+ uptake by miconazole and ethidium bromide in yeasts: role of vacuoles in Ca2+ detoxification.

The antifungal antibiotic miconazole and the cationic dye ethidium bromide, both caused K+ efflux, membrane depolarization and intracellular acidification in the yeast Saccharomyces cerevisiae. Whereas miconazole inhibited the activity of the plasma membrane H+-ATPase, no such inhibition was observed using ethidium bromide at concentrations up to 600 microM. Low concentrations of both drugs caused marked stimulation of the energy dependent Ca2+ uptake.

Effects of inhibitors of plasma-membrane ATPase on potassium and calcium fluxes, membrane potential and proton motive force in the yeast Saccharomyces cerevisiae.

The plasma membrane ATPase inhibitors N,N-dicyclohexylcarbodiimide (DCCD), diethylstilboestrol and sodium orthovanadate caused inhibition of proton ejection in Saccharomyces cerevisiae at a concentration range of 0.1-0.4 mM.

Biotransformation of homofolate from a growth inhibitor to a growth-promoting derivative.

Homofolic acid (HF) was found to inhibit the growth of Lactobacillus casei ATCC 7469 in 100 ng/ml or higher concentrations in the presence of folic acid (PGA) on short (24-48 h) incubation. HF blocked the uptake of 3HPGA into L. casei cell suspensions.

Effects of estradiol on uptake of folate in isolated intestinal epithelial cells.

Estradiol 17 beta caused significant changes in the time course of 3H-folate uptake into isolated chick-intestinal epithelial cells. The radioactivity within the cells initially increased reaching a level of 1.5-2 times that of the control thereafter decreased to somewhat below the control levels.

Nystatin effects on cellular calcium in Saccharomyces cerevisiae.

The primary effects of nystatin, a polyene antibiotic, on the yeast Saccharomyces cerevisiae were investigated. Though K+ leakage was observed shortly after the addition of nystatin, Ca2+ leakage was delayed 2-3 h after its application and it occurred only at an acidic pH and in the absence of K+, Na+ or Mg2+ from the medium. However, within 4 min after application nystatin induced a passive influx of Ca2+ into the cells even at a concentration of 1 microM in the medium.

Effect of phenytoin on folic acid uptake in isolated intestinal epithelial cells.

The anticonvulsant drug phenytoin was found to inhibit the uptake of folic acid into isolated chick intestinal epithelial cells. At a concentration of 100 micrograms/ml the drug inhibited the cellular accumulation of folic acid by 60%. The efflux of folic acid from preloaded cells was not affected by the drug.

Effect of insulin on folic-acid transport in cultured fibroblasts.

Uptake of folic acid was measured in secondary cultures of skin fibroblasts from fetal rats. The cultures were made quiescent by 24 hours preincubation in medium containing 1% serum and subsequent 3 hours preincubation in phosphate buffered saline. The uptake of 3H-folic acid was linear with time during 15 seconds and reached a plateau level at 2-3 minutes.

Physiological and enzymatic properties of a thymidine-requiring Pediococcus cerevisiae mutant.

We describe the isolation and characterization of a Pediococcus cerevisiae thymidine-requiring mutant and its thymidine-independent revertant. The mutant strain lacked thymidylate synthetase activity and had an absolute requirement for low concentrations (2 micrograms/ml) of thymidine in addition to a requirement for N-5-formyl tetrahydrofolic acid (folinate). Even at high concentrations (up to 500 micrograms/ml), thymine could not replace thymidine.

Diagnosis of iron deficiency anemia in a rural population of children. Relative usefulness of serum ferritin, red cell protoporphyrin, red cell indices, and transferrin saturation determinations.

The diagnostic usefulness in iron deficiency anemia of serum ferritin, red cell protoporphyrin (Epp), mean corpuscular volume, mean corpuscular hemoglobin (MCH), and transferrin saturation measurements has been studied in a population of 294 children aged 1 to 6 yr. Of the children studied 19% had hemoglobin below 11 g/dl. Iron deficiency, diagnosed by at least two abnormal independent laboratory parameters, was the cause of anemia in all except two cases.

Cryoprotected Lactobacillus casei: an approach to standardization of microbiological assay of folic acid in serum.

Folate-depleted, cryoprotected preparations of Lactobacillus casei are stable for at least eight months at -18 degrees C, capable of reproducible growth and suitable as a ready source of inoculum for measurement of folates in physiological fluids. Cryoprotected microorganisms can be a commercially available laboratory reagent, thus simplifying and further standardizing the microbiological assay of various nutriments. Standard folate growth curves of cryoprotected L.

On the mechanism of folate transport in isolated intestinal epithelial cells.

The mechanism of folic acid (FA) uptake was studied in isolated intestinal epithelial cells prepared from 2- to 6-wk-old chicks. The cells accumulated FA, reaching a level of three- to fivefold that at equilibrium. In the presence of the metabolic inhibitors, NaN3 or KCN, FA was taken up only until equilibration while accumulation of FA was inhibited.

Anemia among Druze children in the Golan Heights.

The prevalence and causes of anemia were studied in 294 Druze children aged 10 months to six years. The hemoglobin level was less than 11.0 g/dl in 19%; none of these anemic children had folate deficiency.

Improved lysozyme assay in biological fluids.

We describe a simple, rapid, sensitive, and highly reproducible assay for lysozyme, with use of concentrated cell suspensions of Micrococcus lysodeikticus in Tris-buffered glycerol/water (40/60 by vol), pH 7.5. Stored at -20 degrees C, the cells' susceptibility to lysozyme remains unaltered over long periods.

Prevalence and causes of anemia in elderly hospitalized patients.

The prevalence and causes of anemia have been studied in 104 patients over 60 years of age admitted to a general medical ward in Jerusalem. In males and females, mean hemoglobin levels were about 1 g less than in the corresponding groups of healthy younger controls. A primary nutritional anemia could not be implicated in any of the 15 patients with hemoglobins below 11 g/dl.