Cell density dependence of Microcystis aeruginosa responses to copper algaecide concentrations: Implications for microcystin-LR release

Along with mechanistic models, predictions of exposure-response relationships for copper are often derived from laboratory toxicity experiments with standardized experimental exposures and conditions. For predictions of copper toxicity to algae, cell density is a critical factor often overlooked. For pulse exposures of copper-based algaecides in aquatic systems, cell density can significantly influence copper sorbed by the algal population, and consequent responses. A cyanobacterium, Microcystis aeruginosa, was exposed to a copper-based algaecide over a range of cell densities to model the density-dependence of exposures, and effects on microcystin-LR (MC-LR) release. Copper exposure concentrations were arrayed to result in a gradient of MC-LR release, and masses of copper sorbed to algal populations were measured following exposures. While copper exposure concentrations eliciting comparable MC-LR release ranged an order of magnitude (24-h EC50s 0.03-0.3mg Cu/L) among cell densities of 10⁶ through 10⁷ cells/mL, copper doses (mg Cu/mg algae) were similar (24-h EC50s 0.005-0.006mg Cu/mg algae). Comparisons of MC-LR release as a function of copper exposure concentrations and doses provided a metric of the density dependence of algal responses in the context of copper-based algaecide applications. Combined with estimates of other site-specific factors (e.g. water characteristics) and fate processes (e.g. dilution and dispersion, sorption to organic matter and sediments), measuring exposure-response relationships for specific cell densities can refine predictions for in situ exposures and algal responses. These measurements can in turn decrease the likelihood of amending unnecessary copper concentrations to aquatic systems, and minimize risks for non-target aquatic organisms.

Effects of Cutrine-Plus® algaecide and predators on wood frog (Lithobates sylvaticus) tadpole survival and growth

Copper contamination is increasing in many aquatic ecosystems. One mode by which copper can be introduced into aquatic ecosystems is as an algaecide, such as Cutrine-Plus®. Using a mesocosm experiment, we examined the effects of Cutrine-Plus® on wood frog (Lithobates sylvaticus) tadpoles. In addition, we examined how the presence of a nonnative predator the Western mosquitofish (Gambusia affinis) may interact with exposure to Cutrine-Plus®. Exposure to our low and high Cutrine-Plus® treatments had a strong negative effect on the wood frog tadpoles, and survivorship was greatly decreased in the low treatment, and no tadpoles survived in the high treatment. Additionally, the tadpoles that survived the low treatment were significantly smaller than those in the control treatment. Mosquitofish had no effect on the survivorship or growth of wood frog tadpoles, and mosquitofish presence did not have a significant interaction with the Cutrine-Plus® treatments. Cutrine-Plus® clearly had a negative effect on wood frog tadpoles at the concentrations used in our experiment, which were at and below the label-recommended dosages, suggesting that the use of Cutrine-Plus® in natural ponds may have negative consequences for wood frog populations and possibly other amphibians.

Algicidal effectiveness of Clearigate, Cutrine-Plus, and copper sulfate and margins of safety associated with their use

Laboratory studies of algicide toxicity to algal species provide information to improve the efficacy and efficiency of copper-containing algicides in actual field situations. The objectives of this study were (1) to measure the influence of copper form, initial concentration, and duration of exposure on the response of Raphidocelis subcapitata, a planktonic freshwater green alga; (2) to determine the contact time required for these copper-containing algicides (Clearigate, Cutrine-Plus, and copper sulfate) and the target species to obtain control; (3) to measure the critical burden of the three algicides required to obtain control of R. subcapitata; (4) to measure the residence time of the copper applied as the algicides in the water column of three waters having different water characteristics ( i.e., alkalinity, hardness, pH, and conductivity); and (5) to contrast exposures of copper (as algicides) required to control algae and the lower thresholds causing adverse effects on sensitive nontarget animal species. Algal control (EC(100)) was accomplished at 55.8, 117.5, and 187.5 microg Cu/L for CuSO(4), Cutrine-Plus and Clearigate with a contact time of 3 days in all cases. The critical burdens of copper (concentration sorbed by the algae) were 4.2, 7.3, and 7.9 microg Cu/mg algae (dry weight) for CuSO(4), Cutrine-Plus, and Clearigate, respectively. Because algicide toxicity generally decreases as cell density increases, the density of cells in algal blooms may hamper algicide effectiveness even at maximum label application rates. Determinations of critical burdens for algicides and target algal species provide necessary information to forecast the performance of algicide applications in field situations. The margin of safety ( i.e., the difference between the concentration where control of algae was obtained and the lower threshold concentration causing adverse effects on nontarget species) was greatest for Cutrine-Plus. However, the margins of safety are minimal (< 0, 12.5, and 82.5 microg Cu/L for Ceriodaphnia dubia exposed to CuSO(4), Clearigate, and Cutrine-Plus, respectively) when they are applied according to their labels.

Cytotoxicity of amino alcohols to rat hepatoma-derived Fa32 cells

Amino alcohols are used as emulsifying agents in dry-cleaning soaps, wax removers, cosmetics, paints and insecticides. The cytotoxicities of 12 amino alcohols, which differed in chain length, position of the amino and alcohol groups, and the presence of an additional phenyl group, were determined by the neutral red uptake inhibition assay with normally cultured, glutathione-depleted or antioxidant-enriched Fa32 rat hepatoma-derived cells. Glutathione depletion and antioxidant enrichment were achieved by including 50(M L-buthionine-S,R-sulphoximine (BSO) or 100(M (-tocopherol acetate (vitamin E) in the culture medium for 24 hours before and during the assay. The cytotoxicity of the amino alcohols observed after treatment for 24 hours was expressed as the concentration of compound needed to induce a 50% reduction in neutral red uptake (NI50). The observed NI50 values ranged from 3mM to 30mM. The individual stereoisomers and a racemic mixture of 1-amino-2-propanol exhibited similar cytotoxicities (with normally cultured Fa32 cells, and vitamin E- and BSO-treated cultures). Similar NI50 values for D-(+)-2-amino-1-propanol, 3-amino-1-propanol and the L-, D- or DL- forms of 1-amino-2-propanol, indicated that the position of the amino group had little influence on the cytotoxicities of the amino alcohols. In contrast, the position of the hydroxyl group appeared to play an important role for the toxicity of the compound, as indicated by the significantly different NI50 values for 4-amino-1-butanol and 4-amino-2-butanol. An additional phenyl group greatly increased the cytotoxicity of 2-amino-1,3-propanediol. For most of the compounds, cytotoxicity increased when GSH was depleted, and decreased when the cells were enriched with vitamin E. This indicated that most of the tested chemicals interact with GSH, either directly or indirectly, by processes which generate oxygen free-radicals. Decreased toxicity was found for most of the chemicals administered to vitamin E-enriched cells, indicating that reactive oxygen species could be involved in the toxicity of the amino alcohols.

Synthesis and in vitro cytotoxicity of long chain 2-amino alcohols and 1,2-diamines

The synthesis of enantiomerically pure unsaturated long chain 1,2-diamines and amino alcohols was carried out starting from the corresponding non-natural alpha-amino acids. The in vitro cytotoxicity of the compounds prepared was evaluated against six solid tumor cell lines (A2780, H322, LL, WiDr, C26-10 and UMSCC-22B). Free 1, 2-diamines proved to be the most active compounds exhibiting IC50 values between 2.0 mM and 3.3 mM.

Toxicity and bioavailability of copper herbicides (Clearigate, Cutrine-Plus, and copper sulfate) to freshwater animals

In designing aquatic herbicides containing copper, an important goal is to maximize efficacy for target species while minimizing risks for nontarget species. To have a margin of safety for nontarget species, the concentration, duration of exposure (i.e., uptake), and form (i.e., species) of copper used for herbicidal properties should not elicit adverse effects on populations of nontarget species. To determine the potential for risk or adverse effects (conversely the margin of safety), data regarding the comparative toxicity of copper-containing herbicides are crucial. A series of comparative toxicity experiments was conducted, including baseline estimates of toxicity (LC50s, LOECs), sensitive species relationships (thresholds and exposure-response slopes), and bioavailability of toxic concentrations and forms of copper 7 days after initial herbicide application. Aqueous 48-h toxicity experiments were performed to contrast responses of Daphnia magna Strauss, Hyalella azteca Saussure, Chironomus tentans Fabricius, and Pimephales promelas Rafinesque to copper herbicides: Clearigate(R), Cutrine(R)-Plus, and copper sulfate. D. magna was the most sensitive aquatic animal tested for all three herbicides; 48-h LC50s for organisms exposed to Clearigate, Cutrine-Plus, and copper sulfate were 29.4, 11.3, and 18. 9 microg Cu/L, respectively. In terms of potency (calculated from the linearized portion of the exposure-response curves, which included 50% mortality), D. magna was the most sensitive animal tested. Organisms exposed to Clearigate, Cutrine-Plus, and copper sulfate had exposure-response slopes of 2.55, 8.61, and 5.07% mortality/microg Cu/L, respectively. Bioavailability of Clearigate and Cutrine-Plus was determined by comparing survival data (LC50s) of test organisms exposed to herbicide concentrations during the first and last 48-h of a 7-day exposure period. Even in these relatively simplified water-only exposures, a transformation of copper to less bioavailable species over time was observed with a 100-200% decrease in toxicity (i.e., an increase in 48-h LC50s) for all four test animals. This series of laboratory experiments provides a worst-case scenario for determining the risk associated with the manufacturer's recommended application rates of Clearigate (100-1,000 microg Cu/L), Cutrine-Plus (200-1,000 microg Cu/L), and copper sulfate (100-500 microg Cu/L) in natural waters for four nontarget freshwater animals.

Synthesis, in vitro cytotoxicity and in vivo anti-inflammatory activity of long chain 3-amino-1,2-diols

The synthesis of long chain 3-amino-1,2-diols was carried out based on Sharpless asymmetric epoxidation of long chain allylic alcohols and regioselective nucleophilic ring opening by azido group. The in vitro cytotoxicity of the compounds prepared was evaluated against six solid tumor cell lines (A2780, H322, LL, WiDr, C26-10, UMSCC-22B). Free 3-amino-1,2-diols exhibited IC50 values between 1.45 microM and 32 microM. These compounds also presented interesting inhibition of carrageenin-induced paw edema in rats (85.3% - 79.6% at a concentration of 0.15 mmol/kg).

Environmental assessment of the alkanolamines

This review provides a summary of current information available on the environmental fate and aquatic toxicology of the alkanolamines. Because these materials are widely used, there is a need to understand their fate and effects in the environment. This assessment was confined to information regarding selected physical properties of the alkanolamines as well as their potential for degradation in the atmosphere, soil, surface water, and groundwater. In addition, their relevant aquatic toxicological information and bioconcentration potential were evaluated. In general, the alkanolamines have high water solubilities and low to moderate vapor pressures. Some are solids whereas others are liquids at room temperature. Aqueous solutions of the alkanolamines are basic, with the pKas decreasing with increased alkyl substitution. Predictions of the environmental distribution of these compounds, based on a unit world model of Mackay and Paterson, suggested that alkanolamines would partition primarily into the aqueous compartment at equilibrium, with the remainder distributed to the atmosphere. Only a very small fraction of these materials is expected to sorb to soil or sediments. However, adsorption mechanisms other than partitioning into the soil organic layer were not considered in this model. Since polar compounds may sorb to soil by alternate mechanisms, this model may underestimate the true adsorption potential and subsequent environmental distribution of the alkanolamines. Future work with these compounds should focus on other types of adsorption mechanisms that could impact the environmental distribution of the alkanolamines. Although only small amount of the alkanolamines are expected to partition to the atmosphere, they are expected to be removed by reactions with photochemically generated hydroxyl radicals. They may also be removed from the atmosphere by precipitation, due to their high water solubility. Because of the relatively low levels expected to be present in the atmosphere and the relatively short half-lives, the alkanolamines are not expected to adversely impact air quality. Alkanolamines have also been shown to be highly susceptible to biodegradation and are not expected to persist in the environment. Results from numerous studies have shown that these materials undergo rapid biodegradation in soil, surface waters, and wastewater treatment plants. Degradation rates for these compounds may vary, with half-lives routinely in the range of 1 d to 2 wk, depending on the length of acclimation period and other environmental factors. The relatively low bioconcentration factor (BCF) values reported for the alkanolamines indicate that they would not be expected to bioconcentrate in aquatic organisms. Available data on the toxicity of the alkanolamines to aquatic organisms suggest low toxicity to the majority of the species studied. Based on the facts that alkanolamines exhibit low aquatic toxicity, are shown to biodegrade in a wide range of environments, and exhibit no tendency to bioaccumulate, the routine manufacturing, use, and disposal of these materials are not expected to adversely impact the environment. With increased emphasis by consumers and regulatory agencies for industry to develop products that are "environmentally friendly," these properties of the alkanolamines make them an attractive choice for a wide range of applications.

(RS), (R)(-) and (S)(+) derivatives of 2-N-arylalkylamino-1-butanol having antiarrhythmic properties

A series of theophyllinyl-7'-ethyl derivatives of (RS), (R)(-) and (S)(+) 2-aminobutanol were synthesized and tested in various models of experimental arrhythmia for their preventive and curative properties; (R)(-) 2-N-theophyllinyl-7'-ethyl amino-1-butanol (1a) and (R)(-) theophyllinyl-7'-ethyl-2-N-methylamino-1-butanol (3a) hydrochlorides showed interesting antiarrhythmic properties. The levorotatory compounds of R configuration showed stronger protective and also therapeutic effect in different experimental arrhythmias.

The effect of some 8-aminoalkanol derivatives of theophylline on cardiovascular system

Novel 7,8-disubstituted theophyllines 1-6a, with chiral or achiral moiety of 1,2-aminoalcohol in position 8, were obtained as the compounds with expected activity on circulation. Preliminary evaluation of their antiarrhythmic activity and the effect on the cardiovascular system was carried out. The antiarrhythmic activity similar to that of quinidine (with ca. 20 times lower toxicity) was found only for racemic 7-beta-hydroxyethyl-8-(1'-hydroxybut-2'-yl) aminotheophylline 1 and its enantiomers 2, 3 which did not differ markedly in their efficacy. The compounds with the hydroxyethyl moiety in position 7 of theophylline (1-3, 5) showed the hypotensive effect.

Synthesis of p-menthane derivatives with potential biological activity

The synthesis of amino ketones and amino alcohols in p-menthane series is presented. These compounds were obtained in Mannich reaction, starting from the unsaturated ketone p-mentha-6,8-dien-2-one and its saturated analogue p-menthan-2-one. The structures of the compounds obtained were established by means of chemical transformations and elemental and spectral (IR, 1H NMR) analysis. The compounds obtained were subjected to the pharmacological investigations.

The histamine releasing properties of some agents used in textile industry

The inflammatory effect of some compounds (polyglycolamines and polyglycolalcohols condensated with various number of ethylene oxide groups) used in textile industry were investigated as to their action on skin vascular permeability in rats and histamine release from rat peritoneal mast cells. The intradermal injection of tested agents caused the inflammatory skin reactions of various intensity depending on time, dose and chemical structure of agent used. It has been also shown that these properties of tested compounds were correlated with their histamine releasing activity and seemed to be dependent on their chemical structure, namely, the number of ethylene oxide groups in molecule. It is suggested that the histamine release induced by tested compounds is of cytotoxic nature since it depends neither on metabolic energy nor on extracellular calcium.

Potentiation of antitussive effect of codeine by some 1-dimethoxyphenyl-3-alkylaminobutanols in guinea pigs

Newly synthesized 1-(2',5'-dimethoxyphenyl)-1-n-butyl-3-diethylaminobutanol (compd. 4) and its analogs enhanced the antitussive effect of codeine and morphine as tested on the cough induced by mechanical stimulation of the trachea in guinea pigs. This effect was illustrated to be a potentiation on the Gaddum's diagram. The following parameters were affected little or to a small extent: 1. analgesic effect of codeine and morphine in guinea pigs and mice, 2. duration of anesthesia induced by hexobarbital in mice, 3. respiratory depression caused by codeine in guinea pigs, and 4. LD50 of codeine in guinea pigs and mice. Explorations of the mechanism of potentiating action suggested some peripheral mechanism, but the exact one remained to be elucidated.