Mechanism of acute silver toxicity in marine invertebrates

In freshwater crustaceans and in both freshwater and marine fish, the key mechanism of acute silver toxicity involves ionoregulatory impairment. An inhibition of the Na+ ,K+-ATPase located at the basolateral membrane of the gill epithelium seems to be the key site for silver toxicity. However, studies to determine if the same mechanism of toxicity is occurring in marine invertebrates, which also are ionoregulators, had not been done. Thus, the present study was carried out to determine acute silver effects on hemolymph osmo- and ionoregulation in three marine invertebrates: the shrimp Penaeus duorarum, the sea hare Aplysia californica, and the sea urchin Diadema antillarum. Animals were exposed to silver (1 or 10 microg/L), as silver nitrate, in seawater for 48 h. Results show that acute silver exposure did not affect hemolymph osmolality or ion concentration (Na+, Cl-, K+, Ca2+ and Mg2+) in the three species studied. However, silver induced significant changes in the water content in shrimp gill and sea hare gill and hepatopancreas. Silver also caused significant changes in Na+ ,K+-ATPase activity and in both total and intracellular ion (Cl-, Na+, K+, Mg2+, and Ca2+) concentrations in different tissues of the three species studied. Overall, these results show that the key mechanism of acute silver toxicity in marine invertebrates is not associated with an osmotic or ionoregulatory impairment at the hemolymph level, as observed in freshwater fish and crustaceans and in seawater fish. However, they indicate that acute waterborne silver induces significant changes in Na+ ,K(+)-ATPase activity and probably affects other mechanisms involved in water and ion transport at the cell membrane level, inducing impairments in water and ion regulation at the cellular level in different tissues of marine invertebrates. These results indicate the need to consider other "toxic sites" than gills in any future extension of the biotic ligand model (BLM) for seawater.     

Toxicity of ammonia to three marine fish and three marine invertebrates

Laboratory toxicity tests were performed to obtain more data on the toxicity of ammonia to saltwater organisms. The standards for in-stream ammonia limits in marine environments presently are based on toxicity tests involving both freshwater and saltwater organisms. Acute tests (48 and 96 h) were performed at 20 degrees C, and chronic tests (7 days) were performed at 25 degrees C. Synthetic seawater and natural seawater from the Chesapeake Bay were used and compared. Included among the organisms tested were sheepshead minnow (14 days old), summer flounder (2 months old), Atlantic silverside (14 days old), mysid shrimp (less than 2 days old), ghost shrimp (10 days old), and quahog clam (9 months old). Based on these results, it seems the chronic criterion for ammonia in marine environments could be increased from 0.035 to 0.081 mg/L un-ionized ammonia, which would, of course, increase the chronic limit for total ammonia under typical saltwater conditions by a factor of 2.31. No difference was observed in the toxicity of ammonia in natural water compared to synthetic water for both the summer flounder and Atlantic silverside. Furthermore, the Atlantic silverside became more sensitive to ammonia as the salinity was increased from 14 to 22 ppt, but exhibited no change in toxicity response from 22 to 30 ppt.     

Toxicity of phenanthrene and lindane mixtures to marine invertebrates

Surface waters near industrialized and agricultural areas are contaminated with hundreds of different pollutants from a variety of sources. Methods for measurement of sediment, surface water, and porewater toxicity in marine environments include the sea urchin (Arbacia punctulata) fertilization and embryological development tests and copepod (Schizopera knabeni) survival and hatching success assessment. The concentration addition model was applied to determine whether toxicity of two compounds, phenanthrene (polycyclic aromatic hydrocarbon) and lindane (organochlorine pesticide), when combined can be accurately assessed because of similar modes of action. Mixture analysis determined the sea urchin fertilization test to exhibit additivity (TU(mix) = 1.13), while the copepod test exhibited a synergistic effect (TU(mix) = 0.22). Mixture toxicity data for the sea urchin embryological test were not conclusive because of the lack of toxicity of the individual chemicals. The synergistic effect to copepods is a concern as it indicates that greater toxic effects may occur when the compounds are present in mixtures. Results from this research suggest that increased toxicity to some categories of organisms should be expected near agricultural and industrial areas where pesticides and other types of compounds may occur simultaneously.     

Aquatic toxicology of cypermethrin. I. Acute toxicity to some freshwater fish and invertebrates in laboratory tests

Cypermethrin is a synthetic pyrethroid. Its acute toxicity to ten freshwater invertebrates (Daphnia magna, Asellus aquaticus, Gammarus pulex, Cloeon dipterum, Gyrinus natator, Chironomus thummi, Aedes aegypti Cheoborus crystallinus, Corixa punctata, and Piona carnea) was determined in the laboratory using 24-h static water tests. The 24-h EC₅₀ values (based on reduced motility) ranged from 0.02 μg·l^?1for A. aquaticus and P. carnea to 2 μg·l^?1 for D. magna, and for seven of the species the EC₅₀ values were < 0.1 fig μg·l^?1 The 24-h LC₅₀values for G. natator, C. thummi, and C. punctata were > 5 μg·l^?1 For the seven more susceptible species the 24-h LC₅₀values ranged from 2 μg·l^?1 to 0.05 μg·l^?1The acute toxicity of cypermethrin to some species of fish (Cyprinus carpio. Scardinius erythrophthalmus, Salmo gairdneri, Salmo trutta and Tilapia nilotica) was determined using 96-h continuous-flow tests. The 96-h LC₅₀ values obtained were within the range 0.4–2.2 μg·l^?1.The solubility of cypermethrin within the range of test temperatures (15–25°C was estimated to be in the range 5–10 μg·l^?1.     

Comparative toxicity of imidacloprid and thiacloprid to different species of soil invertebrates

Neonicotinoid insecticides have come under increasing scrutiny for their impact on non-target organisms, especially pollinators. The current scientific literature is mainly focused on the impact of these insecticides on pollinators and some aquatic insects, leaving a knowledge gap concerning soil invertebrates. This study aimed at filling this gap, by determining the toxicity of imidacloprid and thiacloprid to five species of soil invertebrates: earthworms (Eisenia andrei), enchytraeids (Enchytraeus crypticus), Collembola (Folsomia candida), oribatid mites (Oppia nitens) and isopods (Porcellio scaber). Tests focused on survival and reproduction or growth, after 3–5 weeks exposure in natural LUFA 2.2 standard soil. Imidacloprid was more toxic than thiacloprid for all species tested. F. candida and E. andrei were the most sensitive species, with LC₅₀s of 0.20–0.62 and 0.77?mg/kg dry soil for imidacloprid and 2.7–3.9 and 7.1?mg/kg dry soil for thiacloprid. EC₅₀s for effects on the reproduction of F. candida and E. andrei were 0.097–0.30 and 0.39?mg/kg dry soil for imidacloprid and 1.7–2.4 and 0.44?mg/kg dry soil for thiacloprid. The least sensitive species were O. nitens and P. scaber. Enchytraeids were a factor of 5–40 less sensitive than the taxonomically related earthworm, depending on the endpoint considered. Although not all the species showed high sensitivity to the neonicotinoids tested, these results raise awareness about the effects these insecticides can have on non-target soil invertebrates.     

Baseline and oxidative DNA damage in marine invertebrates

Anthropogenic pollutants produce oxidative stress in marine organisms, directly or following generation of reactive oxygen species (ROS), potentially resulting in increased accumulation of DNA strand breaks quantified. The aim of this study is to quantify baseline levels of DNA strand breaks in marine species from four phyla and to assess relative sensitivity to oxidative stress as well as ability to recover. DNA strand breaks were determined using a formamidopyrimidine DNA glycosylase (Fpg)-amended comet assay in circulating cells from blue mussel (Mytilus edulis), shore crab (Carcinus maenas), sea star (Asterias rubens), and vase tunicate (Ciona intestinalis). Lymphocytes from Atlantic cod (Gadus morhua) were used as a reference. In addition to immediate analysis, cells from all species were exposed ex vivo to two concentrations of hydrogen peroxide (H₂O₂) at 25 or 250 μM prior to assay. Mean baseline DNA strand breaks were highest for cells from sea star (34%) followed by crab (25%), mussel (22%), tunicate (17%), and cod (14%). Circulating cells from invertebrates were markedly more sensitive to oxidative stress compared to cod lymphocytes. DNA strand breaks exceeded 80% for sea star, crab, and mussel cells following exposure to the lowest H₂O₂ concentration. There was no recovery for cells from any species following 1 hr in buffer. This study provides an in-depth analysis of DNA integrity for ecologically important species representing 4 phyla. Data indicate that circulating cells from invertebrates are more sensitive to oxidative stress than cells from fish as evidenced by DNA strand breaks. Future studies need to address the extent to which DNA strand breaks may exert consequences for body maintenance costs in marine invertebrates.     

Acute toxicity of pinnatoxins E, F and G to mice

The acute toxicities to mice of pinnatoxins E, F and G, members of the cyclic imine group of phycotoxins, by intraperitoneal injection and/or oral administration, have been determined. These substances were all very toxic by intraperitoneal injection, with LD₅₀ values between 12.7 and 57 μg/kg. Pinnatoxin E was much less toxic by oral administration than by intraperitoneal injection, but this was not the case for pinnatoxin F. The median lethal doses of the latter substance by gavage and by voluntary intake were only 2 and 4 times higher than that by injection. The high oral toxicity of pinnatoxin F raises concerns as to the possibility of adverse effects of this substance in shellfish consumers, although it should be noted that no toxic effects in humans have been recorded with pinnatoxins or with any other compound of the cyclic imine group.     

Differential sensitivity of three marine invertebrates to copper assessed using multiple biomarkers

Understanding how biomarkers relate to each other on exposure to particular contaminants in different species is key to their widespread application in environmental management. However, few studies have systematically used multiple biomarkers in more than a single species to determine the variability of sublethal effects of a particular contaminant. In this study, three marine invertebrates, the shore crab Carcinus maenas, the common limpet Patella vulgata and the blue mussel Mytilus edulis, were exposed over 7 days in the laboratory to environmentally realistic concentrations of the priority pollutant copper. A combination of molecular, cellular and physiological biomarkers was measured in each organism to detect the toxic effects of copper. Biomarkers included lysosomal stability (neutral red retention), neurotoxicity (acetylcholinesterase activity), metabolic impairment (total haemolymph protein), physiological status (heart rate) and induction of protective metallothionein proteins. P. vulgata was the most sensitive to copper with significant effects measured in all biomarkers at concentrations of 6.1 microg Cu l(-1). In C. maenas, cellular and neurotoxic endpoints were affected significantly only at 68.1 microg Cu l(-1). Exposure to copper also induced metallothionein production in crabs. Over a 7-day exposure period, M. edulis was the most tolerant species to copper with significant effects being observed at the cellular level only at 68.1 microg Cu l(-1) . In all three species, cellular and neurotoxic pathways were more sensitive to disruption than physiological processes (protein and heart rate). Results illustrate how a suite of biomarkers applied to different sentinel species can provide a 'diagnosis of stress', whereby, effects at the molecular level can be used to interpret the level of physiological impairment of the organism.     

Bioactivities of six sterols isolated from marine invertebrates

Context: Epidioxy sterols and sterols with special side chains, such as hydroperoxyl sterols, usually obtained from marine natural products, are attractive for bioactivities.

Objective: To isolate and screen bioactive and special sterols from China Sea invertebrates.

Materials and methods: Two hydroperoxyl sterols (1 and 2) from the sponge Xestospongia testudinaria Lamarck (Petrosiidae), three epidioxy sterols (3–5) from the sea urchin Glyptocidaris crenularis A. Agassiz (Glyptocidaridae), sponge Mycale sp. (Mycalidae) and gorgonian Dichotella gemmacea Milne Edwards and Haime (Ellisellidae) and an unusual sterol with 25-acetoxy-19-oate (6) also from D. gemmacea were obtained and identified. Using high-throughput screening, their bioactivities were tested toward Forkhead box O 3a (Foxo3a), 3-hydroxy-3-methylglutaryl CoA reductase gene fluorescent protein (HMGCR-GFP), nuclear factor kappa B (NF-κB) luciferase, peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α), protein-tyrosine phosphatase 1B (PTP1B), mitochondrial membrane permeabilization (MMP) and adenosine monophosphate-activated protein kinase.

Results: Their structures were determined by comparing their nuclear magnetic resonance data with those reported in the literature. Three epidioxy sterols (3–5) showed inhibitory activities toward Foxo3a, HMGCR-GFP and NF-κB-luciferase with the IC₅₀ values 4.9–6.8?μg/mL. The hydroperoxyl sterol 29-hydroperoxystigmasta-5,24(28)-dien-3-ol (2) had diverse inhibitory activities against Foxo3a, HMGCR-GFP, NF-κB-luciferase, PGC-1α, PTP1B and MMP, with IC₅₀ values of 3.8–19.1?μg/mL.

Discussion and conclusion: The bioactivities of 3–5 showed that 5α,8α-epidioxy is the active group. Otherwise, the most plausible biosynthesis pathway for 1 and 2 in sponge involves the abstraction of an allylic proton by an activated oxygen, such as O₂, along with migration of carbon–carbon double bond. Therefore, the bioactive and unstable steroid should be biosynthesized in sponge under a special ecological environment to act as a defensive strategy against invaders.     

化瘀消肿酒急性毒性、长期毒性、皮肤刺激性和过敏性研究

<正>化瘀消肿酒(Huayu xiaozhong jiu,HYXZJ)起源于清朝道光年间李氏传统中医正骨术经验方,由桃仁、赤芍、当归尾等17种中药,在白酒中浸泡所得,现为重庆市涪陵李志沧骨科医院的医院制剂。其在临床上广泛应用于治疗软组织损伤,具有活血化瘀、消肿止痛的功效。本研究参照中药、天然药物非临床安全性评价的相关指导原则对该制剂进行安全性试验,为其在临床上的安全应用提供合理的科学依据。1材料与方法1.1材料     

Chemical and pharmacological significance of natural guanidines from marine invertebrates

Natural Guanidines from marine invertebrates represent a group of bioactive secondary metabolites that revealed prominent pharmacological activities such as antimicrobial, antiproliferative, analgesic, and anti-coagulant properties. Acyclovir (Zovirax(?)), the first guanidine-derived pharmaceutical for the treatment of herpes infections since late 1970s, was synthesized based on a marine arabinosyl nucleoside, spongosine. Recently, ziconotide (Prialt(?)), a synthetic form of the marine-derived peptide (ω-conotoxin MVIIA) comprising a guanidine moiety, has been approved for the treatment of chronic pain. This review surveys over 130 compounds of guanidine-containing secondary metabolites from marine invertebrates with emphasis on their pharmacological significance and structure-activity relationships.     

米索前列醇的急性毒性和长期毒性

小鼠皮下注射和灌胃米索前列醇(Mis)的LD_(50)分别是37.1和56.4mg/kg。大鼠灌胃Mis0.6,2和6mg/(kg·d)30d,红细胞和血红蛋白升高,血糖和总蛋白量降低(均在正常范围);前列腺的脏器系数减小。撤药d15,上述改变均恢复到对照水平。病理检查示Mis导致曲精细管上皮严重受损,生精细胞减少至消失,尤以6mg/(kg·d)组为甚,撤药d15生精细胞增多。提示长期大量应用Mis对雄性生殖系统产生可逆性损伤。     

Acute, subacute and subchronic toxicity of besulpamide

The acute oral and intraperitoneal toxicity of besulpamide has been studied in the rat and mouse, together with the subacute and subchronic oral toxicity in the rat at doses of 0, 125, 500 and 2000 mg/kg/day. The LD50 is in excess of 12,800 mg/kg by the oral route and in excess of 5,000 mg/kg intraperitoneally. Toxic signs were very slight and autopsy did not reveal lesions which could be attributed to the test substance. In the subacute and subchronic toxicities the characteristic effects of the diuretic activity were observed. In the subchronic toxicity study significant, although not dose-related, increases were observed in calcium, alkaline phosphatase, GPT and GOT levels. A decrease in liver-weight of the female animals with respect to controls was also noted. Histopathological studies did not reveal any changes which could be attributed to administration of the test substance. Besulpamide has demonstrated the typical effects of diuretics which are derivatives of 3-sulfamoyl-4-chlorobenzoic acid and in acute, subacute and subchronic tests by the oral route in the rat it has shown itself to be a substance of very low toxicity.     

Acute, subacute and chronic toxicity of oxepinac

The acute, subacute and chronic toxicity of 6,11-dihydro-11-oxodibenz[b,e]oxepin-3-acetic acid (oxepinac) was investigated in several animal species. The LD50 value was lower in rats than in rabbits, mice and dogs. The major cause of death was perforative ulcer in the gastrointestinal tract. Long-term study in rats revealed that oxepinac produced no hematological, blood chemical and pathological changes except for minor anemia and fatal ulcer formation occurring predominantly in females. Oxepinac proved to be less toxic than indometacin in chronic toxicity in rats.     

Acute toxicity of tricyclohexyltin hydroxide to livestock

Thirty adult sheep of both sexes were treated intrarumenally with tricyclohexyltin hydroxide. Groups of five sheep each were treated with 750, 500, and 250 mg/kg; groups of four sheep each were given 150, 25, and 15 mg/kg; and three sheep received 50 mg/kg. All were affected except the sheep treated with 15 mg/kg. Sheep treated with 750 and 500 mg/kg had severe cardiovascular and respiratory changes at necropsy. On dermal treatment, no ill effect was observed in eight yearling cattle (two per group) sprayed with suspensions of 0.025, 0.05, 0.1, and 0.5%. Three yearling cattle were anorectic after being sprayed with the 1.0% suspension. Two baby calves (one per group) tolerated spraying at 0.075 and 0.1%. Fifteen yearling Angora goats (five per group) tolerated exposure by spraying with the 0.025, 0.05, and 0.1% suspensions. Transitory anorexia and eye irritation were noted in three goats sprayed with the 2.0% suspension. Of 15 sheep (five per group) sprayed at 0.025, 0.05, and 0.1%, no ill effect was observed. Three of five sheep were mildly affected when sprayed at 0.5%. At the 1.0% spraying, one sheep was affected and died, three sheep were mildly affected and survived, and one was unaffected. Of two sheep sprayed at 2.0%, one was mildly affected and survived, but the other sheep was affected, aborted, and died of complications.     

Acute toxicity of copper to the threespine stickleback, Gasterosteus aculeatus

This study focuses on characterizing the acute toxicity of copper in freshwater to the threespine stickleback, Gasterosteus aculeatus, a small and widely distributed euryhaline fish. The threespine stickleback is used as an effluent monitoring species in both Canada and the United States, yet in some locations natural populations are listed as threatened or endangered. Four 96-h static renewal acute toxicity tests were performed in moderately hard water using U.S. EPA methods with adult fish (mean wet weight = 0.41 g/fish). The geometric mean of the 24-, 48-, 72- and 96-h LC(50)s based on measured concentrations of total copper (estimated dissolved copper in parentheses) in the test solutions were 382.2 (366.9), 278.7 (267.6), 256.6 (246.3), and 227.2 (218.1) microg Cu/L, respectively. Conservative estimates of acute toxicity thresholds, made using LC1 values, for adult threespine sticklebacks over 24-, 48-, 72- or 96-h exposure periods in moderately hard water are approximately 114.3 (109.7), 78.3 (75.2), 67.0 (64.3), and 52.4 (50.3) microg Cu/L, respectively. Test results were normalized to a range of water hardness from very soft to very hard using two U.S. EPA methods, the water hardness and the Biotic Ligand Model normalization procedures. Subsequently, interspecies sensitivity comparisons were made with aquatic animal species used in both the current and proposed U.S. EPA copper water quality criteria documents. Information reported in this study may be useful in effluent toxicity identification evaluations, ecological risk assessments and criteria development where copper is a concern.     

Acute toxicity of vanadium to the threespine stickleback, Gasterosteus aculeatus

Vanadium is widely distributed, occurring in many types of minerals, coal, and petroleum. Anthropogenic sources of vanadium originate from the production, processing, and wastes of these materials. The aquatic toxicity of vanadium to fish species is not well characterized. This study focused on the three-spined stickleback, Gasterosteus aculeatus, a small and widely distributed euryhaline species of fish. The three-spined stickleback is used as an effluent-monitoring species in both Canada and the United States. Five 96-h static renewal acute toxicity tests were performed in moderately hard water with adult fish. The geometric mean and range of the five 96-h LC(50)s based on measured concentrations of total vanadium in the test solution were 3.17 and 2.35-4.07 mg V/L, respectively. A conservative estimation of a safe concentration of vanadium that would not affect survival of adult three-spined sticklebacks over a 96-h exposure period in moderately hard water is approximately 0.30 mg V/L. A comparison with other fish species previously tested suggests that the three-spined stickleback is intermediate in sensitivity to vanadium. Information reported from this study may be useful in effluent toxicity identification evaluations and ecological risk assessments related to vanadium.     

Acute toxicity of gymnodimine to mice.

The acute toxicity of the phycotoxin gymnodimine to female Swiss mice by intraperitoneal injection and by oral administration has been determined. Gymnodimine was highly toxic by injection, the LD50 being only 96 microg/kg. Animals either died within 10 min of injection or made a full recovery with no perceptible long-term effects. Gymnodimine was also toxic after oral administration by gavage (LD50 755 microg/kg), but was much less toxic when administered with food. No signs of toxicity were seen in mice voluntarily ingesting food containing gymnodimine at a level sufficient to give a dose of approximately 7500 microg/kg. Pre-treatment with physostigmine or neostigmine protected against injected gymnodimine, suggesting that the latter exerts its toxic effects via blockade of nicotinic receptors at the neuromuscular junction. The low toxicity of gymnodimine when ingested with food suggests that this compound is of low risk to humans, a conclusion that is consonant with anecdotal evidence for the absence of harmful effects in individuals consuming shellfish contaminated with gymnodimine.