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.     

Micromethod for the determination of tryptophan

Translated from Khimiko-farmatsevticheskii Zhurnal, Vol. 28, No. 7, pp. 51–55, July, 1994.     

Micromethod for determination of ceftriaxone in plasma and urine by high-performance liquid chromatography

A sensitive and rapid high-performance liquid chromatographic method for the determination of ceftriaxone in human plasma and urine is described. A C18 reversed phase column is used; the mobile phase comprises water-methanol-triethylamine (750:250:4v/v/v) adjusted to pH 3 with orthophosphoric acid. Quantitation is performed at 270 nm with cefazolin as the internal standard. This method involves precipitation of proteins from fluids with acetonitrile followed by extraction of endogenous compounds with chloroform and injection of the upper aqueous phase on to the chromatograph. Relative standard deviations for between-day and within-day assays are 6.2%. The detection limit is 0.5 mug(-1) in plasma and urine. Studies of drug stability during sample storage, sample pretreatment and chromatography showed no degradation of ceftriaxone or of the internal standard. The method is convenient for clinical monitoring and for pharmacokinetic studies.     

Two essential modifications strongly improve the performance of the Fast Micromethod to identify DNA single- and double-strand breaks

To identify DNA single- or double-strand breaks, various techniques have been described. One of them, the Fast Micromethod, is an easy-to-perform 96-well microplate assay. Cells treated with chemicals are loaded with the fluorescent dye PicoGreen, which binds to double-stranded DNA with a high specificity. Following DNA denaturation in an alkaline buffer, DNA unwinding occurs and PicoGreen is released. The amount of PicoGreen released over a certain period of time reflects the extent of DNA damage. To maximize the throughput of the procedure and to minimize DNA damage due to the analytical procedures used, the Fast Micromethod was improved in two essential points. First, the very time-consuming cell-counting was substituted by a simple protein measurement. Second, the cell lysis step was omitted. By introducing the two above mentioned modifications, a high number of samples can now be analyzed within a much shorter period of time.     

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.     

Micromethod for the determination of phospholipids (author's transl)

Optimal conditions for separation and analysis of phospholipids in very small tissue samples have been elaborated. The phospholipid pattern of the rat vena portae and arteria mesenterica was determined.     

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.     

Genotoxic effects of selected biocides on RTG-2 fish cells by means of a modified Fast Micromethod Assay

A sensitive in vitro assay for detecting DNA damage in RTG-2 cells culture is described. This assay employs a dye, PicoGreen double stranded DNA (dsDNA) quantitation reagent, which becomes intensely fluorescent upon binding nucleic acids. The assay includes a simple and rapid 50-min sample lysis in the presence of EDTA, SDS, and high urea concentration at pH 10, followed by time-dependent DNA denaturation at pH 11.6 after NaOH addition. The time course and the extent of DNA denaturation are followed in a microplate fluorescence reader at room temperature for less than 1h. Comparative studies between suspension and fixed RTG-2 cells indicated that it is possible to apply this methodology in both cases with good results. Neutral red assay was used for to determine the cellular viability when RTG-2 cultures were exposed to tetrakis(hydroxymethyl) phosphonium chloride (THPC) and benzalkonium chloride (BC), as biocides used in the disinfection of cooling towers. The results obtained by neutral red assay indicate IC(50(48)) values of 0.017 (0.011-0.028) and 2.71 (1.91-3.86) mg/L for tetrakis(hydroxymethyl) phosphonium chloride and benzalkonium chloride, respectively. DNA damage has been evaluated for both disinfectants in RTG-2 culture, by exposure to 1/10-, 1/25-, 1/50-, and 1/100-IC(50(48)) value, and the results obtained indicate a strain scission factor (SSF) of 0.126+/-0.014, 0.181+/-0.014, 0.217+/-0.013, and 0.245+/-0.013 in cell suspensions, and 0.077+/-0.019, 0.107+/-0.014, 0.151+/-0.014, and 0.202+/-0.015 in attached cells for tetrakis(hydroxymethyl) phosphonium chloride; while the SSF values for benzalkonium chloride are 0.023+/-0.009, 0.033+/-0.017, 0.068+/-0.012, and 0.088+/-0.015 in cell suspensions, and 0.033+/-0.010, 0.044+/-0.011, 0.080+/-0.009, and 0.093+/-0.010 in attached cells. Thus, the assay proposed in this study has made it possible to show DNA damage in RTG-2 cells when exposed to 0.2(1/100 IC(50(48))) and 300(1/10 IC(50(48))) Hg/L of tetrakis(hydroxymethyl) phosphonium chloride and benzalkonium chloride, respectively. The results obtained indicate that the Fast Micromethod Assay, applied on RTG-2 cell line cultures, is a fast and sensitive method for the early DNA damage detection in the aquatic environment.     

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.     

海洋无脊椎动物中α-葡萄糖苷酶抑制剂的初步研究

目的 对青岛地区的海洋无脊椎动物粗提物进行α-葡萄糖苷酶抑制荆的初步筛选.方法采用α-葡萄糖苷酶抑制剂活性筛选模型,对采自青岛沿海的33种海洋无脊椎动物乙醇粗提物进行了活性筛选.结果33种海洋无脊椎动物粗提物中,宥10种具有不同程度的α-葡萄糖苷酶抑制剂活性.其中海筒螅、海燕、刺参和毛蚶的粗提物表现出较强的活性,在浓度为0.6 mg·mL-1时,分别为56.1%、67.3%、62.2%、66.3%.结论某些海洋无脊椎动物中存在具有α-葡萄糖苷酶抑制活性的成分,值得进一步研究开发.     

Lead in the marine environment: concentrations and effects on invertebrates

Ecotoxicology - Lead (Pb) is a non-essential metal naturally present in the environment and often complexed with other elements (e.g., copper, selenium, zinc). This metal has been used since...     

Micromethod for the determination of bupivacaine in maternal and foetal blood during obstetric analgesia

A method for the determination of bupivacaine in maternal and foetal blood during obstetric analgesia is described. The drug and the internal standard, 1-pentyl-2-(2,6-xylylcarbamoyl)-piperidine, are initially extracted into methylene chloride. Perchloric acid is added to retain bupivacaine and the standard as Perchlorates in the organic phase accomplishing a selective separation from less hydrophobic amines. Bupivacaine and the standard are then re-extracted into sulphuric acid, followed by a purification with methylene chloride. The aqueous extract is finally made alkaline and the compounds extracted into 10 μl methylene chloride. This extract is analysed by gas chromatography using a 3% OV-17 column. The standard deviation of the method at therapeutic concentrations is about 10% and the lowest level which can be determined with reasonable accuracy is 15 ng ml^?1.     

基于遗传算法结合最小二乘支持向量机的秦皮提取液快速定量分析方法

目的:探讨遗传算法(genetic algorithm,GA)结合最小二乘支持向量机(least squares support vector machine,LSSVM)用于秦皮提取液中多组分含量的快速测定的可行性。方法:以HPLC分析值作为参照,采集不同产地的秦皮提取液的紫外光谱,运用GA算法筛选光谱特征波长,再对筛选结果应用主成分分析(pricipal component analyze,PCA)进行特征提取,结合LSSVM算法建立快速测定秦皮甲素、秦皮乙素及秦皮素的数学模型。结果:应用GA算法筛选后,秦皮甲素、秦皮乙素、秦皮素的建模光谱维数分别下降为全谱的44%,44%,32%,所建模型的预测集相关系数(RP)分别为秦皮甲素0.948 6,秦皮乙素0.960 3,秦皮素0.929 3,预测均方根(RMSEP)分别为秦皮甲素0.085 2,秦皮乙素0.033 4,秦皮素0.012 1。结论:GA算法可以在充分保留光谱有效信息的基础上,显著降低模型的复杂度,结合LSSVM算法建立的模型可以用于快速测定秦皮提取液中秦皮甲素、秦皮乙素及秦皮素的含量,为中药提取液的质量控制提供新思路。     

Fast determination of retinol and alpha-tocopherol in plasma by LC

A fast, selective and economical method for the determination of retinol and alpha-tocopherol is presented. Both vitamins are separated by high-performance liquid chromatography (HPLC) in less than 4 min using an isocratic elution with methanol. The robustness of the method was checked in real samples, obtaining relative standard deviation lower than 3%. The described method was satisfactorily applied to serum samples proceeding of patients enrolled in a METHADONE maintenance treatment program. The retinol concentrations in the serum of these patients fell into the normal interval of concentrations; however, the serum alpha-tocopherol contents were higher than the normal values.