Glacins A and B: two novel bioactive mono-tetrahydrofuran acetogenins from Annona glabra

Two new bioactive mono-THF Annonaceous acetogenins, glacins A (1) and B (2), have been isolated, from the fractionated ethanolic extracts of the leaves of Annona glabra, directing the fractionation with the brine shrimp lethality test (BST). The structures of 1 and 2 were elucidated on the basis of spectroscopic and chemical methods, and the absolute stereochemistries were solved by preparing their respective per-Mosher ester derivatives. 1 and 2 showed potent and selective in vitro cytotoxicities among several human solid tumor cell lines.

Developmental toxicity of three carrier solvents using embryos of the grass shrimp, Palaemonetes pugio

Embryos of the grass shrimp (Palaemonetes pugio) have shown sensitivity to the water soluble fraction of number 2 fuel oil. To determine the possible use of carrier solvents in grass shrimp bioassays, detailed concentration-response experiments for ethanol (EtOH), dimethylsulfoxide (DMSO), and acetone were performed and LC50 values were obtained using two test methods. The 4-d assay included development prior to the time of hatch through the time of hatch, a critical life stage of these embryos. The 12-d assay included development from the tissue cap stage embryos (late gastrula) through two days post-hatch. The average 4-d LC50s for EtOH, DMSO, and acetone were 12.07, 22.57, and 6.78 g/L, whereas the average 12-d LC50s were 3.63, 12.33, and 6.94 g/L, respectively. The coefficient of variation for each test was less than 25.2%. Based on concentration-response curves, the maximum allowable limit of EtOH, DMSO, and acetone to be used as a carrier in the grass shrimp embryo toxicity studies should be <1, <6, and <4 g/L, respectively.

Acute and chronic toxicity of azinphos-methyl to two estuarine species, Mysidopsis bahia and Cyprinodon variegatus

The acute and chronic toxicity of azinphos-methyl (Guthion) was evaluated for two estuarine species in the laboratory. Mysids (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus) were selected as the representative invertebrate and vertebrate estuarine test species, respectively. The toxicological endpoints determined for each species included the 96-h LC50, the no-observed-effect concentration (NOEC), the maximum acceptable toxicant concentration (MATC), and the acute-to-chronic ratio. The 96-h LC50 value derived for sheepshead minnows (2.0 microg/L) was seven times higher than the 96-h LC50 value (0.29 microg/L) derived for mysids. The MATCs were 0.024 microg/L and 0.24 microg/L for the mysid and the sheepshead minnow, respectively. The estimated acute-to-chronic ratios were 12 for mysids and 8.3 for sheepshead minnows.

Correlation between overall pesticide effects monitored by shrimp mortality test and change in macrobenthic fauna in a river

The relationship between change in benthic fauna in the Suna River and shrimp mortality in the river water samples (test was conducted two times per week from May to September) was investigated to assess the insecticide impact on the benthic community. The river was selected because pesticide application had been restricted for a long time in the upper reaches, while aerial insecticide spraying had been done four times on paddy fields in the lower reaches in summer. Species richness and density of benthos were high at the stations in the upper reaches. High shrimp mortality was measured in the water samples collected from a downstream station during the pesticide spraying period, from late July to late August. Species richness and density of benthos markedly decreased at the stations in the lower reaches in that period. However, several species of chironomids, Cheumatopsyche (Trichoptera), which demonstrated tremendous insecticide resistance, and Baetis sahoensis (Ephemeroptera), which has a high recovery potential, were not affected, even in the insecticide spraying period. The benthic fauna in the lower reaches tended to recover from autumn to spring, although not sufficiently. It is considered that the temporal recovery of the benthic community was brought about through recruitment from the benthic community in the 5-km upper reaches. A close correlation was found between the high mortality of shrimp in the water samples and the deterioration in the benthic fauna in this river which was contaminated with insecticides during the summer.

[Toxicity of atrazine and its metabolite deethylatrazine in Thamnocephalus platyurus and Dugesia gonocephala]

The toxicity of Atrazine and that of its Desethylatrazine metabolite has been defined employing two organisms already tested in our labs the Dugesia gonocephala, belonging to a scissiparous strain coming from the island of Tavolara (Sardinia) and the Thamnocephalus platyurus, crustacean anostracan produced under form of quiescent cysts from Creasel Ltd. (Deinze, Belgium). It has been defined the lethal concentrations at 50% of Atrazine and of Desethylatrazine, of which it has been studied also the report dose-effect in the comparisons of the rectilinear motility. The results highlight that in the comparisons of the T. platyurus Atrazine expounds a toxicity of around three times that of its metabolite; this is not seen with the Planarians that are equally sensitive to both the compounds. The use of these two experimental models for the evaluation of the contamination of bodies of water is shown to be particularly useful given their great sensitivity to pollutants.

[Eco-toxicological study conducted with a battery of biological and phytological tests on sediments carried out on a series of 24 tributaries of the Po in 1994 and 1995]

In spring and autumn 1994 and 1995 affluent water and bed sediment were sampled from 24 tributaries of the Po river, always at the same site and at the nearest place to the confluence. In the laboratory the pore water was separated from the particle fraction of the sediment. The organic compounds bound to the latter component were extracted with solvents and brought to water solution by means of dimethyl sulfoxide. The observed animal species, along with the seeds of Lepidium, were exposed to effluent water, to pore water and to water solutions of the organic compounds extracted from bed sediment. Toxicity was evaluated on the basis of 1) direct lethality, 2) the delay of embryo development, 3) the impairment of regeneration, in the animal species, while the germination index was used for the Lepidium susceptibility. The results of these investigations demonstrate that 1) the challenged species cover a broad range of sensitivities toward environmental toxins, 2) toxicity found in river samples appears almost exclusively bound to the sediment, 3) the noxious effects found in the tributaries of the Po river increase moving downstream, and 4) likewise the sediment-bound toxicity varies among the different samplings, both as a consequence of changes in rain-dependent river flow, and because of the man-made interventions on the river sides and bed.

Residual pesticides and their toxicity to freshwater shrimp in the littoral and pelagic zones of Lake Kasumigaura, Japan

Pesticide residues in water and their toxicity to the freshwater shrimp (Paratya compressa improvisa) were studied in a river mouth in Takahamairi Bay, Lake Kasumigaura, from April to July in 1987. Concentrations of fenthion, diazinon and fenobucarb in water of the littoral zone were lower than that in the pelagic zone. The maximum concentration of fenthion, diazinon, iprobenfos and simetryn in water were 1.9, 0.8, 6.5, and 1.1 micrograms 1(-1), respectively. The 4-day mortality of the freshwater shrimp increased in lake water at Takahamairi Bay, reaching 50% at maximum in May. The mortality was probably due to residual insectside fenthion.

Ionic imbalance as a source of toxicity in an estuarine effluent

A toxicity identification evaluation (TIE) was conducted on the effluent from a petrochemical plant which discharges into an estuary. The effluent had been consistently toxic to mysid shrimp (Mysidopsis bahia) but not toxic to sheepshead minnows (Cyprinodon variegatus). Phase I effluent toxicity characterization tests revealed that treatment of the effluent with a cation exchange resin (Amberlite(R) IR-120 Plus) was partially effective at reducing, but not removing, toxicity. Phase II characterization tests revealed that four cations varied with toxicity: Ca and Sn were positively correlated with increasing toxicity; Mg and K were negatively correlated with increasing toxicity. Toxicity tests with SnCl2 revealed that the toxicity threshold for Sn was far above the concentrations present in the raw effluent. Reduction of Ca was shown to result in a significant improvement in survival, but some toxicity still remained. Further augmentation of the treated effluent with CaCl2, MgCl2, and KBr to restore the concentrations of Ca, Mg, K, and Br to natural seawater concentrations resulted in survival of all exposed organisms. Repeated success of this treatment regime on additional samples of the effluent as well as "mock effluent" studies confirmed that ion imbalance was the sole source of toxicity in this effluent. Process source water composition and essential ion balance are discussed as important components of marine effluent TIEs.

Subacute toxicity of the water-soluble fractions of Kuwait crude oil and partially combusted crude oil on Menidia beryllina and Palaemonetes pugio

As a consequence of the 1991 Gulf War, a substantial amount of crude oil (CO) and partially combusted crude oil (PCO) were emitted into the environment. Therefore, the study objective was to evaluate the toxicity of the water soluble fraction (WSF) of CO and PCO on a fish, Menidia beryllina, and an invertebrate, Palaemonetes pugio, in 16-d flow-through tests. Specific growth rate (SGR) was studied as a function of total petroleum hydrocarbon (TPHC) concentration in water. Reductions in SGR were observed in fish exposed to PCO and CO WSFs, with TPHC water concentration being 10-fold higher in CO exposures (67-145 microg/L) than in PCO exposures (4-12 microg/L). Significant negative correlations were observed between TPHC concentration and fish SGR in both CO (r2=0.730) and PCO (r2=0.867) exposures, with the slope being significantly lower for PCO exposures (-0.169) than CO exposures (-0.009). Differences between CO and PCO toxicity were not as clear in shrimp exposures due to slow growth rates and variability in TPHC concentrations. Qualitative PAH analysis indicated that naphthalene was present in the CO WSF whereas chrysene and benzo(a)pyrene were present in the PCO WSF. Heavy metal analysis of concentrated stock solutions indicated that the PCO WSF had substantially higher concentrations of some metals (Sr=2,521 microg/L, B=556 microg/L, and Ba=130 microg/L) than the CO WSF in which concentrations were less than 55 microg/L. Fish and shrimp tissue analysis did not reveal any uptake of parent PAH compounds from the water, which may be attributed to the formation of PAH metabolites.

Three dihydroanthracenones from Gasteria bicolor

The stem and leaves of Gasteria bicolor afforded three new dihydroanthracenones namely 3,4-dihydro-2,6,9-trihydroxy-8-methyl-1(2H)-anthracenone (gasteriacenone A), 3,4-dihydro-2,4,9-trihydroxy-6-methoxy-8-methyl-1(2H)-anthracenone (gasteriacenone B) and 3,4-dihydro-4,6,9-trihydroxy-7-carbomethoxy-8-methyl-1(2H)-anthraceno ne (gasteriacenone C). Their structures were determined by spectroscopic methods including 2D NMR techniques.

Ecotoxicity in the Reconquista River, province of Buenos Aires, Argentina: a preliminary study

The Reconquista River in Argentina is considered a "supercritical" river basin due to environmental degradation. Within its valley of 1.547 km2, there are more than 3 million inhabitants and 12,000 industries. Using early-life-stage toxicity tests with Bufo arenarum embryos (the most sensitive of three native species), we determined the water quality at six sampling stations of the river valley and expressed the results as acute and chronic toxicity units. Along most of the river, the toxicity was higher than the allowable level of whole industrial effluent toxicity recommended by U.S. EPA. In a tributary stream, Arroyo Moron, the water was about 10 times more toxic than the criteria maximum concentration (CMC) recommended by U.S. EPA for industrial effluents. Similar degradation of the water quality was found taking as a reference value an upstream sampling station. In all places where the water quality was worse than the CMC, no macroorganisms were found, and in one of these places, a large number of dead fishes was observed. Our study points out that amphibian early-life-stage toxicity tests could be appropriate for assessing water contamination and water quality, which is essential for diagnosis, protection of environmental services, monitoring, and restoration purposes.

Asimilobin and cis- and trans-murisolinones, novel bioactive Annonaceous acetogenins from the seeds of Asimina triloba

Three new bioactive Annonaceous acetogenins, asimilobin [1], cis-murisolinone [2], and trans-murisolinone [3], have been isolated from an ethanolic extract of the seeds of Asimina triloba by directing the fractionation with brine shrimp lethality. The structure were elucidated based on spectroscopic and chemical methods, In addition, cis- and trans-bullatacinone, which are known compounds, were obtained. Asimilobin [1] has adjacent bis-THF rings, located at C-10 to C-17 and having only one flanking hydroxyl group at C-18. Compounds 1-3 showed cytotoxicity values comparable with adriamycin against six human solid tumor cell lines.

An evaluation of the aquatic hazard of cumene (isopropyl benzene)

Cumene manufacturers were required under a TSCA Section 4(a) test rule to evaluate the aquatic toxicity of cumene to daphnids, rainbow trout, mysid shrimp, and sheepshead minnows. Because of cumene's high volatility (vapor pressure, 3.2 mm Hg at 20 degrees C), all tests were conducted under flowthrough conditions using a proportional diluter system. The 96-hr LC50s for rainbow trout, sheepshead minnow, and mysid shrimp, based on mean measured concentrations, were 4.8, 4.7, and 1.3 mg/liter, respectively. The 48-hr daphnid EC50 was 4.0 mg/liter. Although cumene is considered moderately toxic to aquatic organisms under rigorous laboratory conditions, its volatility and biodegradability greatly reduce its hazard to the aquatic environment.

Toxicity of nickel ores to marine organisms

Queensland Nickel proposes to import New Caledonian (Ballande) and Indonesian (Gebe) nickel ores, one option being ship-to-barge transfer in Halifax Bay, North Queensland. Because small amounts of ore may be split during the unloading and transfer operations, it was important to investigate the potential impact of the spilt ore on the ecological health of the Bay. Long-term leaching of the ores with seawater showed that only nickel and chromium (VI) were released from the ores in sufficient concentrations to cause toxicity to a range of marine organisms. The soluble fractions of nickel and chromium (VI) were released from the ores within a few days. Nickel, chromium (VI) and the ore leachates showed similar toxicity to the juvenile banana prawn Penaeus merguiensis, the amphipod Allorchestes compressa and both temperature (22 degrees C) and tropical (27 degrees C) strains of the unicellular marine alga Nitzschia closterium. In a series of 30-day sub-chronic microcosm experiments, juvenile leader prawns Penaeus monodon, polychaete worms Galeolaria caespitosa and the tropical gastropod Nerita chamaeleon were all very resistant to the nickel ores, with mortality unaffected by 700 g ore per 50 l seawater. The growth rate of the leader prawns was, however, lower than that of the controls. From these data, a conservative maximum safe concentration of the nickel ores in seawater is 0.1 g l-1. The nickel ore was not highly toxic and if spilt in the quantities predicted, would not have a significant impact on the ecological health of the Bay.

Antiulcerative properties and acute toxicity profile of some African medicinal plant extracts

The aqueous extract of the stem bark of Tetrapleura tetraptera Schum et Thonn., Guibourtia ehie Leonard and the root extract of Taverniera abyssinica A. Rich. were used for the treatment of gastrointestinal related clinical problems in African ethnomedicine. HCl/EtOH-induced ulceration was used in fasted rat stomach to investigate the anti-ulcerative properties of the extracts. The acute cytotoxicity of the extracts using brine shrimp larvae was also investigated. The aqueous extracts of Tav. abyssinica (250-500 mg/kg), Tet. tetraptera (500-1000 mg/kg), G. ehie (500-1000 mg/kg) and a combination of Tet. tetraptera and G. ehie (1:4) (500-1000 mg/kg) produced significant (P < 0.05) inhibition (54-80%, 86-98%, 48-80% and 54-92%, respectively) of the HCl/EtOH-induced ulceration of the stomach compared with controls. The acute cytotoxic concentrations of the extracts which killed 50% (LC50) of brine shrimp within 24 h was 438 micrograms/ml for Tet. tetraptera, 220 micrograms/ml for the 1:4 combination of Tet. tetraptera and G. ehie and 1409 micrograms/ml for Tav. abyssinica. None of the shrimp were killed by G. ehie, even at 2 mg/ml.

Differential haemotoxic effect of PCB congeners in the common shrimp, Crangon crangon

1. Specimens of the common shrimp, Crangon crangon, were exposed to sub-acute logarithmically separated concentrations (ranging from 0.05 microgram to 500 micrograms l-1) of two structurally dissimilar PCB congeners (PCB 15 and PCB 77) for five days in vitro. 2. Mortality, recoverable haemolymph volume, haemocyte count, plasma protein and haemolymph osmolarity were determined for test animals together with levels of haemolymph cell prophenoloxidase, an indicator of immune potential. 3. Sub-acute concentrations of PCB 15, but not PCB 77, produced significant decreases in haemocyte count and phenoloxidase activity with a marked increase in recoverable haemolymph volume. 4. No effect was observed on haemolymph osmolarity or plasma protein levels with either PCB 77 or PCB 15.

In vitro inhibition of Ca+2 ATPase by methylparathion in prawn: a kinetic approach

After in vitro addition of IC50 concentration of methylparathion on Ca+2 ATPase in nervous and hepato-pancreatic tissues of prawn were studied. The inhibitory pattern of Ca+2 ATPase elucidate the interaction of methylparathion with ATPase system. The significant decrease in maximal velocity (Vmax) without appreciable change in apparent Michaelis-Menten constant (Km) suggests that the impact of methylparathion on Ca+2 ATPase is independent of substrate and is of a classical non-competitive type.

The effect of sub-lethal doses of dieldrin on the ventilatory and cardiac activity in two species of shrimps

The effect of dieldrin on the heart and ventilatory activity in the shrimps Macrobranchium faustinum and Macrobrachium amazonicum was studied over 4 and 7 day exposure periods, respectively. In M. faustinum, ventilatory rate increased by 43% and heart rate by 14.4%. In M. amazonicum, the ventilatory and heart rates decreased by 21 and 6%, respectively. In M. amazonicum ventilatory reversal frequency, an index of respiratory stress, was 6.7 times higher than the control values. All the changes, except for M. amazonicum heart rate were significant at the 0.01 level of probability.

The effect of sub-lethal doses of dieldrin on resting and active metabolism in two species of shrimps

The effects of dieldrin on the active (VaO2) and resting (VrO2) oxygen consumption rates of the shrimps Macrobrachium faustinum (De Sassure) and Macrobrachium amazonicum (Heller) were studied during exposure for 4 days at 0.01 p.p.b. and 7 days at 0.0002 p.p.b., respectively. The VrO2 of M. faustinum increased significantly (P less than 0.01) by 48% but the VaO2 decreased by 13%. The VrO2 and VaO2 decreased by 43 and 70%, respectively, in M. amazonicum. Thus, in both species the aerobic metabolic scope for activity decreased. The increased resting metabolic rate of the indigenous M. faustinum is ascribed to energy consuming responses which allow compensation for the effects of the stressor. The stressor may be said to have moved this species into a metabolic "zone of compensation". The decreased resting metabolic rate of the pond-cultured M. amazonicum is ascribed to greater susceptibility, more extensive metabolic breakdown and failure of compensatory responses. This species might be said to have been forced by the stressor into a metabolic "zone of collapse".