Carboxymethyl‐β‐cyclodextrin influence on the solubility and toxicity of substituted indole compounds

The solubilization of eight selected substituted indole compounds (SICs) by carboxymethyl‐β‐cyclodextrin (CMCD) in water is reported. The results show that their solubility was well improved in CMCD aqueous solution, and the stoichiometry of inclusion complex of the studied SICs with CMCD was 1: 1. The acute toxicity to Photobacterium phosphoreum of the investigated SICs in CMCD aqueous solutions was also investigated and was compared with that in water. The results show that the toxicity of five studied SICs decreased while the toxicity of the rest three SICs increased in CMCD aqueous solutions, but neither the increase nor the decrease was significant.     

Oxidative stress and changes in locomotor behavior and gill morphology of Gambusia affinis exposed to chromium

Sublethal effects of chromium trioxide on mosquito fish, Gambusia affinis, were carried out for 28 days on day 4, 8, 12, 16, 20, 24, and 28. The sublethal effects of chromium (LC₁₀, 77.62?mg?L^?1) on antioxidant enzymes, thiobarbituric acid reactive substance (TBARS), locomotor behavior, and gill morphology were studied. The antioxidant enzymes like superoxide dismutase (SOD) and catalase were induced throughout the exposure span of 28 days. Percent induction was also increase with the days of exposure. Lipid peroxidation product, malondialdehyde was enhanced in the viscera tissue of chromium-exposed fish. Perturbation of locomotor behavior like decrease in distance travelled (m?min^?1) and in swimming speed (cm?s^?1) was observed in exposed fish. Chromium toxicity caused alterations in gill morphology like hypertrophy and hyperplasia in secondary lamellae followed by detached epithelium with severe necrosis. It can be concluded from the results that Cr intoxication in Gambusia fish, caused induction in antioxidant enzymes and lipid peroxidation, plus changes in gill morphology and locomotor behavior.     

Comparative sensitivities of the tropical cladoceran,Ceriodaphnia rigaudii and the temperate species Daphnia magna to seven toxicants

The toxicities of seven chemicals [cadmium (Cd) chloride, potassium dichromate, sodium dodecyl sulfate, potassium chloride (KCl), Triton X-100, zinc (Zn) chloride and copper (Cu) (II) sulfate] were determined using the tropical freshwater cladoceran, Ceriodaphnia rigaudii and the temperate species, Daphnia magna. Data generated was subsequently used to determine the relative sensitivities of both species, using interspecies correlation to compare the 48?h LC50 values for both species. The 48?h LC50 values for C. rigaudii ranged from 0.002?mg?L^?1 (potassium dichromate) to 21.1?mg?L^?1 (KCl), whereas those for D. magna ranged from 0.3?mg?L^?1 for Cu to 418.87?mg?L^?1 for KCl. The LC50 values for C. rigaudii were significantly less than that for D. magna for six of the compounds tested. The interspecies correlation also showed a low, positive correlation suggesting that the sensitivities of both species were not similar for the compounds tested. The sensitivity factors for C. rigaudii and D. magna ranged between 0.01 and 12.3. These values further suggested that for six of the compounds tested, C. rigaudii appeared to be more sensitive than D. magna. It is therefore possible that because of these differences in relative sensitivities, toxicity data generated with D. magna may not be appropriate for Trinidad.     

Amelioration of fluoride toxicity by vitamins and calcium on reproductive organs of female rat

Normal female rats of Wistar strain (Rattus norvegicus) weighing between 150–200 g were treated with fluoride (Fl) contaminated drinking water (FW, 5.8 ppm), vitamin C (6 mg) and vitamin C (6 mg) + D (6 mg once a week) + calcium (6 mg) for 30 days. Fl water treatment to rats produced reduction in weights of ovaries, uterus, vagina, kidneys, and adrenal glands, circulating levels of estrogen, number of litters, fertility rate, and altered tissue and serum biochemistry compared to control rats. However, cholesterol concentrations of ovaries and adrenals increased significantly. The above altered parameters were restored partially/completely after exogenous feeding with vitamin C and vitamins (C + D) and calcium. The data suggest that Fl-induced adverse effects on reproductive and other organs in female rats, whereas vitamin C, vitamin D and calcium treatment ameliorated Fl toxicity. Therefore, vitamins (C and D) and calcium play an important role in prophylactic treatment of fluorosis.     

An approach for assessing the suitability of Ceriodaphnia rigaudii as an indigenous tropical toxicity test species

Although the selection criteria for toxicity test species are well-documented, they do not provide a clear approach for establishing the suitability of a species for regulatory testing. This study looks at the approach used to determine if Ceriodaphnia rigaudii, an indigenous tropical cladoceran species, may be designated as a suitable freshwater test species for regulatory testing in Trinidad and Tobago. The approach involved species identification, life cycle characterization, salinity tolerance, toxicological responses to standard chemicals, and comparative sensitivity evaluation with an established test species. The results showed that C. rigaudii (0.45 mm) was significantly smaller in size, had a shorter life cycle and matured faster than temperate cladoceran species such as Ceriodaphnia dubia and Daphnia magna (3–6 mm). Ceriodaphnia rigaudii has a life span of about 10–15 days and reached sexual maturity within 2 days, whereas D. magna had a life span of about 40–50 days and attained sexual maturity within 6–10 days. The LC₅₀ values for C. rigaudii were significantly less than D. magna for the six compounds tested. Interspecies correlation also showed a low positive correlation, suggesting that the sensitivities of both species were not similar for the compounds tested. The sensitivity factors of C. rigaudii and D. magna for the toxicants ranged 0.01–12.3, suggesting that C. rigaudii was more sensitive than D. magna. This study was useful in defining a stepwise approach to help establish C. rigaudii as an indigenous tropical toxicity test species in Trinidad.     

Purification,characterization and toxicity of a mannose-binding lectin from the seeds of Treculia africana plant

In this study, a mannose-specific, homodimeric lectin from the seeds of Treculia africana was purified, characterized and its adverse effects were investigated in mice. The purification protocol involved anionic exchange chromatography on DEAE-Cellulose followed by gel filtration on Sephadex G-100. The hemagglutinating activity of lectin towards human erythrocytes was sensitive to inhibition by D-mannose. Treatment of the protein with EDTA exerted no inhibitory effect; however, analysis of metal content by atomic absorption spectroscopy revealed the presence of Cu²⁺, Fe³⁺, and Mg²⁺. The results obtained showed that the lectin possesses maximum hemagglutinating activity towards human erythrocytes activity over the pH range 3–7.2 and is relatively thermostable up to 50°C. Periodic acid Schiff's (PAS) reagent staining showed that the protein was non-glycosylated while its amino acid composition analysis revealed that the protein contained 155 residues per subunit. The subunit had a minimal molecular weight of 22,139 Daltons, while the native molecular weight was estimated to be 41,000 Daltons. The lectin was found to be moderately toxic to mice with an LD₅₀ of 47.21 µg g^?1 body weight while, histopathological analysis showed no treatment related effects in any of the organs examined.     

3种助剂对赤子爱胜蚓的急性毒性

为了探究新型助剂LD-10与常用助剂NP-10、NP-4对土壤非靶标生物的影响,以赤子爱胜蚓(Eisenia fetida)为受试生物,采用自然土壤法和灭菌土壤法,研究了这3种助剂对土壤蚯蚓的急性毒性.结果表明,在自然土壤中LD-10、NP-10和NP-4对蚯蚓7d半致死浓度w(LC50)分别为482.58、1 077.50和343.17 mg·kg-1,14 d的w(LC50)分别为438.38、984.64和316.65 mg.kg-1.在灭菌土壤中LD-10、NP-10和NP-4对蚯蚓7d的w(LC50)分别为350.71、960.95和309.63 mg·kg-1,14d的w(LC50)分别为320.24、745.99和274.76 mg·kg-1.在自然土壤和灭菌土壤中3种助剂对赤子爱胜蚓均为低毒,毒性由大到小依次为NP-4、LD-10和NP-10,且3者在灭菌土壤中的毒性均明显高于自然土壤.     

不同浓度的五氯酚对斑马鱼运动行为的影响

由于突发性水源污染频发,建立一种实时的风险监测评估系统十分迫切。本研究通过在线生物监测仪实时记录斑马鱼在五氯酚(PCP)中暴露前后的3D行为响应数据,分别从运动轨迹、游动速度(中值)、浮出水面频率及熵值4个指标分析斑马鱼的行为响应。结果表明：与对照组相比,暴露于低浓度(0.25、0.5 mg·L^-1)的PCP中的斑马鱼,其游动速度(中值)和熵值呈递减趋势,但趋势不明显,其浮出水面频率有不同程度的增加;而暴露于较高浓度(1.0、2.0 mg·L^-1)的PCP中的斑马鱼,其游动速度(中值)、浮出水面频率、熵值约有10 min的急速升高之后降低;暴露于高浓度(4.0 mg·L^-1)的PCP中的斑马鱼,所有指标均呈明显下降趋势。这表明斑马鱼的毒性行为响应随PCP的浓度变化而变化,所以可以通过监测鱼类的行为变化来反映水体的污染状况。因此,鱼类行为学研究在高浓度突发性水源污染的实时监测方面具有一定的应用前景。     

泥鳅在污染物毒性评价中的应用研究

泥鳅营底栖生活,生存能力强,易于饲养,便于采集和处理,有作为模式生物的潜力。受到污染物胁迫时,泥鳅在分子、细胞、组织、器官和个体水平上会发生明显的变化,其存活、生长和繁殖从而受到影响。泥鳅的这些特性可以被用来进行污染物毒性评价。从急性毒性、蓄积毒性、生殖力毒性、遗传毒性等方面,综述和分析了泥鳅在污染物毒性评价中的应用研究进展,并对未来研究重点进行了展望。     

BDE-47对斑马鱼胚胎-幼鱼的急性毒性及氧化应激作用

为研究2,2',4,4'-四溴联苯醚(BDE-47)对斑马鱼胚胎-幼鱼急性毒性、氧化应激及细胞凋亡的影响,以受精后3 h的斑马鱼胚胎为染毒对象,用概率单位法计算BDE-47对斑马鱼胚胎-幼鱼的96 h-LC₅₀;再参照96 h-LC₅₀按一定比例级差设置0.25、0.5、1.0、2.0 mg·L^-1 4个浓度组和1个对照组(0 mg·L^-1)进行96 h半静水式毒性试验,检测斑马鱼超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性、丙二醛(MDA)含量和细胞凋亡情况。结果表明,BDE-47对斑马鱼96 h的急性毒性LC₅₀为3.77 mg·L^-1(95%可信区间1.93～10.27 mg·L^-1);2.0 mg·L^-1剂量组与对照组相比,SOD活性和MDA含量显著增加,且CAT活性与BDE-47染毒浓度之间存在明显的剂量-效应关系;0.5 mg·L^-1 BDE-47染毒96 h后,即观察到斑马鱼幼鱼出现明显细胞凋亡,主要集中于神经管和脑部。研究表明,BDE-47可以影响斑马鱼体内抗氧化防御系统,并能诱导细胞凋亡;BDE-47导致神经组织的氧化损伤可能在动物神经毒性中起重要作用。