Aqueous solubility of beryllium(II) at physiological pH: effects of buffer composition and counterions.

Beryllium ion elicits p53-mediated cell cycle arrest in some types of human cancer cells, and it is a potent inhibitor of GSK3 kinase activity. Paradoxically, Be2+ is regarded to have almost negligible aqueous solubility at physiological pH, due to precipitation as Be(OH)2. This study demonstrates that the interaction of Be2+ with serum proteins greatly increases its effective solubility. In typical serum-supplemented mammalian cell culture medium, Be2+ was soluble up to about 0.5 mM, which greatly exceeds the concentration needed for biological activity. Some biochemical studies require protein-free Be2+ solutions. In such cases, the inclusion of a specific inorganic counterion, sulfate, increased solubility considerably. The role of sulfate as a solubility-enhancing factor became evident during preparation of buffered solutions, as the apparent solubility of Be2+ depended on whether H2SO4 or a different strong acid was used for pH adjustment. The binding behavior of Be2+ observed via isothermal titration calorimetry was affected by the inclusion of sodium sulfate. The data reflect a "Diverse Ion Effect" consistent with ion pair formation between solvated Be2+ and sulfate. These insights into the solubility behavior of Be2+ at physiological and near-physiological pH will provide guidance to assist sample preparation for biochemical studies.

Competitive inhibition and selectivity enhancement by Ca in the uptake of inorganic elements (Be, Na, Mg, K, Ca, Sc, Mn, Co, Zn, Se, Rb, Sr, Y, Zr, Ce, Pm, Gd, Hf) by carrot (Daucus carota cv. U.S. harumakigosun).

We investigated the uptake of inorganic elements (Be, Na, Mg, K, Ca, Sc, Mn, Co, Zn, Se, Rb, Sr, Y, Zr, Ce, Pm, Gd, and Hf) and the effect of Ca on their uptake in carrots (Daucus carota cv. U.S. harumakigosun) by the radioactive multitracer technique. The experimental results suggested that Na, Mg, K, and Rb competed for the functional groups outside the cells in roots with Ca but not for the transporter-binding sites on the plasma membrane of the root cortex cells. In contrast, Y, Ce, Pm, and Gd competed with Ca for the transporters on the plasma membrane. The selectivity, which was defined as the value obtained by dividing the concentration ratio of an elemental pair, K/Na, Rb/Na, Be/Sr, and Mg/Sr, in the presence of 0.2 and 2 ppm Ca by that of the corresponding elemental pair in the absence of Ca in the solution was estimated. The selectivity of K and Rb in roots was increased in the presence of Ca. The selectivity of Be in roots was not affected, whereas the selectivity of Mg was increased by Ca. These observations suggest that the presence of Ca in the uptake solution enhances the selectivity in the uptake of metabolically important elements against unwanted elements.

Mobilization and distribution of beryllium over the course of chelation therapy with some polyaminocarboxylic acids in the rat.

The efficacy of three common polyaminocarboxylic acids in the treatment of experimental beryllium intoxication was investigated in male rats. N-(2-hydroxyethyl) ethylene diamine triacetic acid (HEDTA) was more effective than calcium disodium ethylenediamine tetraacetic acid (CaNa2EDTA) in reducing the beryllium concentration of the blood, kidneys and spleen and reducing beryllium-induced inhibition of hepatic alkaline phosphatase activity. HEDTA was also most effective in reducing histopathological lesions in the liver and spleen. Compared to these two chelators, the third amino chelator, calcium trisodium diethylene triaminepenta acetic acid (CaNa3DTPA) produced severe deleterious effects in the liver and systemic toxicity. The results suggest that HEDTA is a promising chelator for beryllium toxicity while DTPA enhances the toxic manifestation of beryllium.

Lung clearance, translocation, and acute toxicity of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium oxides following deposition in rat lung.

Young adult rats were exposed via inhalation or intratracheal instillation to oxides of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium. Serial necropsies were performed to assess the metal content in organs at times up to several weeks after exposure. The lung clearance varied widely for these compounds, and the times to remove 50% of the initial burden ranged from 18 min for vanadium to 400 days for beryllium. Arsenic, cadmium, lead, selenium, and vanadium were initially soluble in lung, but a small fraction (1-20%) remained there over the long term. Extrapulmonary tissues often accumulated substantial amounts of the soluble oxides, and whole-body retention was often greater for compounds that were more soluble in lung. Arsenic, selenium, and vanadium translocated to carcass and bone. Arsenic, cadmium, lead, and selenium accumulated in the liver, and the kidney retained cadmium and lead. Beryllium, cobalt and ytterbium did not deposit at any extrapulmonary site in significant amounts. In general, the aqueous solubility of these compounds was a poor predictor for behavior in vivo because of their interaction with metabolic processes. Of the metal oxides tested for acute lethality following pulmonary deposition, cadmium was most toxic, followed by selenium, vanadium, and arsenic.

Bacteriophage active against the lactic acid beverage-producing bacterium Lactobacillus casei.

A virulent bacteriophage which causes a decrease in acid production during fermentation of a lactic acid beverage named Yakult with Lactobacillus casei was isolated from the abnormal fermentation tank and named PL-1. L. casei S strain was the exclusive host cell among 18 lactic acid bacteria tested. The plaque was round with an average diameter of about 0.5 mm. It exhibited serological cross-reaction with previously isolated J1 phage. Under an electron microscope, the phage had a spermatozoon shape, with an icosahedral head (63 nm) and a long tail (12.5 by 275 nm) with about 55 striae. The free phage particles were stable at pH 5 to 8. The phage was quite sensitive to ultraviolet irradiation or to heating (60 C, 5 min), and the host was more sensitive than the phage to these treatments. Many kinds of antimicrobial chemicals were also phagocidal. Calcium ion (5 mm) was specifically essential for the phage growth cycle. A one-step growth experiment under optimum conditions (37 C and pH 6.0) showed that the eclipse period was about 75 min, that the latent period was 100 min after the phage infection, and that the average burst size was about 200. The possibility of arresting phage development in lactic acid fermentation is discussed.