Toxicity Evaluation of Freshwater Cyanobacterium Microcystis aeruginosa PCC 7806: Ⅱ Nephrotoxicity in Rats

Nephrotoxic potential of laboratory cultures of freshwater cyanobacterium (blue-green al ga) Microcystis aeruginosa PCC 7806 (Pasteur Institute) was assessed in male rats. The ani mals were injected intraperitoneally with 0. 5, 1. 0 and 2. 0 LD50 doses of lyophilized cell ex tract. Elevated plasma urea and creatinine levels were accompanied by decrease in protein and albumin levels, followed by hematuria, proteinuria and bilirubinuria. Also decrease in kidney lactate dehydrogenase and glutamic oxaloacetic transaminase indicated possible nephrotoxic po tential of the cyanobacteria. The extract also produced various hematological changes associat ed with stagnant type of hypoxia. High perfomance liquid chromatography of the culture I dentified the active principle (toxin) as Microcystin-LR

Toxicity Evaluation of in vitro Cultures of Freshwater Cyanobacterium Microcystis aeruginosa:Ⅰ.Hepatotoxic and Histopathological Effects in Rats

Laboratory cultures of freshwater cyanobacterium (blue-green alga) Microcystis aeruginosa PCC 7806 was cvaluated for its hepatotoxic effects in rats. The lyophilized cell extract injected intraperitoneally at 1 and 2 LD50 (15.8 and 31.6 mg/kg, respectively) produced significant increase in liver-specific enzymes viz. plasma alkaline phosphatase,γ-glutamyl transferase, lactate dehydrogenase with a concomitant decrease in hepatic glutamic pyruvic transaminase. A corresponding increase in liver body weight index and histopathological changes in liver (degeneration of hepatocytes, congestion and hemorrhage etc.) are indicative of a dose and time dependent hepatotoxic nature of the algal extract

Study and application of Toxicity Test Method Using Neomysis awatschensis in Toxicity Evaluation of Drilling Fluid

Neomysis awatschensis was collected on the west coast of Jiaozhou Bay, Qingdao in 1992 and acclimated in the laboratory conditions. The acute toxicity method using 4~ 6 day juvenile mysid of this species is studied. The species is compared with M. bahia in taxonomy, geographic distribution, morphology, as well as the sensitivity to reference toxins. Based on the results, we recommend N. awatschensis to be a standard marine organism for toxicity test in China and the method to be applied in toxicity evaluation of drilling fluids. In this paper, we report the results of the above studies and the application of the method in the evaluation of several drilling fluid products.

Toxicity evaluation in a paper recycling mill effluent by coupling bioindicator of aging with the toxicity identification evaluation method in nematode Caenorhabditis elegans

Toxicity identification evaluation (TIE) can be used to determine the specific toxicant(s) in industrial effluents.In the current study,the authors have attempted to combine the advantages of the model organism,Caenorhabditis elegans,with the virtues of the TIE technique,to evaluate and identify the toxicity on aging from a paper recycling mill effluent.The results indicate that only the toxicities from mixed cellulose (MC) filtration and EDTA treatment are similar to the baseline aging toxicity,suggesting ...

UV/H2O2 oxidation of tri(2-chloroethyl) phosphate: Intermediate products, degradation pathway and toxicity evaluation

Tri(2-chloroethyl) phosphate(TCEP) with the initial concentration of 5 mg/L was degraded by UV/H2O2 oxidation process. The removal rate of TCEP in the UV/H2O2 system was 89.1% with the production of Cl-and PO4^3- of 0.23 and 0.64 mg/L. The removal rate of total organic carbon of the reaction was 48.8% and the pH reached 3.3 after the reaction. The oxidative degradation process of TCEP in the UV/H2O2 system obeyed the first order kinetic reaction with the apparent rate constant of 0.0025 min^-1( R^2 = 0.9788). The intermediate products were isolated and identified by gas chromatography-mass spectrometer. The addition reaction of HO · and H2O and the oxidation reaction with H2O2 were found during the degradation pathway of 5 mg/L TCEP in the UV/H2O2 system. For the first time, environment risk was estimated via the "ecological structure activity relationships" program and acute and chronic toxicity changes of intermediate products were pointed out. The luminescence inhibition rate of photobacterium was used to evaluate the acute toxicity of intermediate products. The results showed that the toxicity of the intermediate products increased with the increase of reaction time, which may be due to the production of chlorine compounds. Some measures should be introduced to the UV/H2O2 system to remove the highly toxic Cl-containing compounds, such as a nanofiltration or reverse osmosis unit.

Toxicity evaluation of collagen hydrolysates from chrome shavings and their potential use in the preparation of amino acid fertilizer for crop growth

Resource utilization of chrome shavings(CS)has attracted a lot of attention from scientists and technologists in leather industry.Especially,the collagen hydrolysates extracted from CS are expected to find potential application values in agricultural field.However,there is no biotoxicity analysis of collagen hydrolysates from CS.Herein,the collagen hydrolysates with different molecular weights were produced from CS by three hydrolysis dechroming methods including alkaline hydrolysis,enzymatic hydrolysis and alkaline-enzymatic synergistic hydrolysis,and the optimal hydrolysis process of CS was designed and conducted.To evaluate their toxicity,the three collagen hydrolysates were formulated into a nutrient solution for zebrafish development.The obtained results indicated that the hydrolysates with low concentrations(less than 0.6 mg/mL)were safe and could promote the development for zebrafish embryos.Furthermore,the three collagen hydrolysates were utilized as organic nitrogen sources and formulated into amino acid water-soluble fertilizers(AAWSF)including alkaline type fertilizer(OH),enzymatic type fertilizer(M)and alkaline-enzymatic type fertilizer(OH-M)for the early soilless seeding cultivation of wheat,soybean and rapeseed.It is worth mentioning that the chromium contents in the prepared AAWSF were less than 10 mg/kg,which is far less than the limit value in the standard(China,50 mg/kg).The growth and development of seedlings(germination rate,plant height,fresh weight of leaves,soluble sugar content and chlorophyll content)were investigated.The corresponding results showed that the growth of seedlings watered with AAWSF was better compared with the other treatments,and the OH-M fertilizer had the best promoting effect on the seedlings growth and development,followed by the M and OH fertilizers.The safe toxicity assessment of the collagen hydrolysates will expand their application scope,and the use of collagen hydrolysates extracted from CS for seedlings growth also provides an effective and reason-able way to deal with the chromium-containing leather solid waste,which is an effective way to realize its resource utilization.

Confirmation of combinational effects of calcium with other metals in a paper recycling mill effluent on nematode lifespan with toxicity identification evaluation method

We used toxicity identification evaluation （TIE） method to confirm the combinational effects of identified toxic metals in a paper recycling mill effluent in inducing the decreased lifespan in nematode Caenorhabditis elegans.Exposure to Ca ＋ Al caused more severely decreased lifespan than that exposed to Ca,or Al;and exposure to Ca ＋ Fe induced more severely decreased lifespan than that exposed to Ca,or Fe.Exposure to Ca＋Al＋Fe caused more severely decreased lifespan than that exposed to Ca,or Ca＋Fe.Moreover,the baseline toxicity on lifespan was doubled by doubling the concentration of combined metals （Ca＋Al＋Fe） in spiking test in original effluent （oe）,and lifespan defects in oe＋Ca＋Al＋Fe exposed nematodes were more severe than that in Ca＋Al＋Fe exposed nematode.Therefore,Ca＋Al＋Fe exposure may largely explain the formation of decreased lifespan induced by the examined industrial effluent.Furthermore,the observed reduction of lifespan induced by the combination of high level of Ca with other metals may be at least partially independent of the insulin-like pathway.

Toxicity Assessment of Cyanide and Tetramethylene Disulfotetramine （Tetramine） Using Luminescent Bacteria Vibrio-qinghaiensis and PbO= Electrochemical Sensor

The toxicities of cyanide and tetramethylene disulfotetramine （tetramine） were evaluated by two methods of luminescent bacteria and PbO2 electrochemical sensor. Vibrio-qinghaiensis, a kind of luminescent bacteria, can produce bioluminescence and the bioluminescence was decreased with the addition of toxicants. The toxicities of cyanide and tetrarnine were expressed as 10 min-EC50 value, which was the concentration of chemical that reduces the light output by 50% after contact for 10 min. Nano PbO2 modified electrode, a rapid toxicity determination method was also described in this work. By the PbO2 modified electrode, the current responses of Escherichia coli （E. coli） were changed with the addition of toxicants. The value of 10 min-EC50 was also provided with the PbO2 electrochemical sensor. Compared with the 10 min-EC50 and detection limits （38.38 and 0.60 μg/mL for cyanide, 0.24 and 0.02 μg/mL for tetramine） with luminescent bacteria, the PbO2 sensor provided a simple and convenient method with lower 10 min-EC50 and detection limits （26.37 and 0.52 μg/mL for cyanide, 0.21 and 0.01 μg/mL for tetramine） and fast response time.

Safety profile of two-dimensional Pd nanosheets for photothermal therapy and photoacoustic imaging

Two-dimensional （2D） nanosheets have emerged as an important class of nanomaterial with great potential in the field of biomedicines, particularly in cancer theranostics. However, owing to the lack of effective methods that synthesize uniform 2D nanomaterials with controlled size, systematic evaluation of size-dependent bio-behaviors of 2D nanomaterials is rarely reported. To the best of our knowledge, we are the first to report a systematic evaluation of the influence of size of 2D nanomaterials on their bio-behaviors. 2D Pd nanosheets with diameters ranging from 5 to 80 nm were synthesized and tested in cell and animal models to assess their size-dependent bioapplication, biodistribution, elimination, toxicity, and genomic gene expression profiles. Our results showed size significantly influences the biological behaviors of Pd nanosheets, including their photothermal and photoacoustic effects, pharmacokinetics, and toxicity. Compared to larger-sized Pd nanosheets, smaller-sized Pd nanosheets exhibited more advanced photoacoustic imaging and photothermal effects upon ultralow laser irradiation. Moreover, in vivo results indicated that 5-nm Pd nanosheets escape from the reticuloendothelial system with a longer blood half-life and can be cleared by renal excretion, while Pd nanosheets with larger sizes mainly accumulate in the liver and spleen. The 30-nm Pd nanosheets exhibited the highest tumor accumulation. Although Pd nanosheets did not cause any appreciable toxicity at the cellular level, we observed slight lipid accumulation in the liver and inflammation in the spleen. Genomic gene expression analysis showed that 80-nm Pd nanosheets interacted with more cellular components and affected more biological processes in the liver, as compared to 5-nm Pd nanosheets. We believe this work will provide valuable information and insights into the clinical application of 2D Pd nanosheets as nanomedicines.