Radionuclide accumulation in near-shore sediments along the Bulgarian Black Sea coast

The accumulation of radionuclides in Black Sea marine ecosystems was investigated by low level gamma spectrometry. Artificial as well as natural radionuclides were determined in bottom sediments samples from 35 reference locations along the Bulgarian Black Sea coast, evenly distributed from the Rumanian to the Turkish border including the main Black Sea resorts and rivers. The measurement of radionuclides in sea bed sediments was carried out during six consecutive seasons using a HPGe detector. The data obtained show that the nuclide concentrations depend strongly on the sediment nature. Results for sandy sediments are within close range, while those for slime and silt vary to a much greater extent. The radionuclide content in the sandy sediments of the main Black Sea resorts is at the lowest limit of the determined values. Small seasonal changes of radionuclide concentration in sandy sediments were observed while greater variations in slime and silt occur. From the data obtained ¹³⁴Cs/¹³⁷Cs and ¹³⁷Cs_meas/¹³⁷Cs_Chern ratios are calculated to determine the Chernobyl part of the measured ¹³⁷Cs. The activities determined in the sediments for natural radionuclides correspond to those cited in the literature for natural levels, showing no additional anthropogenic contamination. A data base for the nuclide concentration values was created which will enable the modeling of radionuclide transfers by estimation of their concentration variations, accumulation and influence on the marine ecosystems.     

Penetration of selected Dead Sea minerals through a healthy rabbit skin, from a sustained-release transparent varnish, as a prospective treatment for psoriasis

Bathing in the Dead Sea is an established treatment for psoriasis. Penetration of Dead Sea minerals into psoriatic skin is an effective factor in this treatment, but applying it clinically requires frequent bathing in the Dead Sea or in its bath-salt solution. We tested an ethyl-cellulose-based transparent varnish with a sustained-release property, for its penetrability of such minerals. Minerals tested were MgBr₂, and KBr, known for their relevance in psoriatic proliferation. They were applied for up to three weeks. We could demonstrate that two weekly applications of the salt-containing varnish on healthy rabbit skin are enough to obtain elevated levels of magnesium and potassium in their plasma. We propose the application of Dead Sea minerals containing varnish as a clinical treatment for psoriasis.     

Structure and function of delta-atracotoxins: lethal neurotoxins targeting the voltage-gated sodium channel.

Delta-atracotoxins (delta-ACTX), isolated from the venom of Australian funnel-web spiders, are responsible for the potentially lethal envenomation syndrome seen following funnel-web spider envenomation. They are 42-residue polypeptides with four disulfides and an "inhibitor cystine-knot" motif with structural but not sequence homology to a variety of other spider and marine snail toxins. Delta-atracotoxins induce spontaneous repetitive firing and prolongation of action potentials resulting in neurotransmitter release from somatic and autonomic nerve endings. This results from a slowing of voltage-gated sodium channel inactivation and a hyperpolarizing shift of the voltage-dependence of activation. This action is due to voltage-dependent binding to neurotoxin receptor site-3 in a similar, but not identical, fashion to scorpion alpha-toxins and sea anemone toxins. Unlike other site-3 neurotoxins, however, delta-ACTX bind with high affinity to both cockroach and mammalian sodium channels but low affinity to locust sodium channels. At present the pharmacophore of delta-ACTX is unknown but is believed to involve a number of basic residues distributed in a topologically similar manner to scorpion alpha-toxins and sea anemone toxins despite distinctly different protein scaffolds. As such, delta-ACTX provide us with specific tools with which to study sodium channel structure and function and determinants for phyla- and tissue-specific actions of neurotoxins interacting with site-3.     

Induction of caspase-dependent apoptosis by betanodaviruses GGNNV and demonstration of protein alpha as an apoptosis inducer

Betanodaviruses, members of the Nodaviridae family, are the causative agents of viral nervous necrosis in fish and infection by which cause high mortality in larvae and juveniles in a wide range of marine fish species in Asia, Europe, Australia, Martinique, and Tahit. Greasy grouper (Epinephelus tauvina) nervous necrosis viruses (GGNNV) were investigated for their apoptotic activity in culture cells. GGNNV infection of sea bass (SB) cells appeared to induce a typical cytopathic effect (CPE), i.e., cytoplasmic vacuolation, thinning, rounding up, detachment of infected cells from the cultured dish, and eventually cell lysis and death. The infected SB cells underwent DNA fragmentation and stained positive in terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) assay, suggesting that GGNNV infection induced apoptosis in SB cells. In addition, GGNNV-infected SB cells showed an increased activity of caspase-8-like proteases (IETDase) and caspase-3-like proteases (IETDase), whereas inhibitor of caspase-8 and caspase-3 reduced GGNNV-induced apoptosis. This suggests that GGNNV may promote apoptosis via the extrinsic pathway in SB cells. Protein alpha, the precursor of GGNNV capsid proteins, was transiently expressed in SB and Cos-7 cells. The DNA fragmentation and TUNEL positive signal were apparent in SB and Cos-7 cells expressing protein alpha, suggesting that protein alpha may serve as an apoptotic inducer in these cells. Moreover, expression of protein alpha resulted in the activation of caspase-3-like proteases in both cells, which could be inhibited by a caspase-3-like protease specific inhibitor DEVD-CHO peptide. These results suggest that fish caspases are important elements in GGNNV-meditated apoptosis.     

Dicentrarchus labrax biotransformation and genotoxicity responses after exposure to a secondary treated industrial/urban effluent

The present research work was designed to study Dicentrarchus labrax (sea bass) biotransformation and genotoxicity responses to the soluble fraction of a secondary treated industrial/urban effluent (SF-STIUE) discharged through a submarine pipe outlet into the Aveiro coastal area. Sea bass was exposed for 4, 8, 16, 24, 48, and 96 h to 0%, 0.1%, and 1% SF-STIUE and the following biological responses were measured: (1) liver cytochrome P450 (P450) content and ethoxyresorufin-O-deethylase (EROD) activity, as phase I biotransformation parameters; (2) liver gluthathione S-transferase (GST) activity as a phase II conjugation enzyme; (3) biliary and liver cytosol naphthalene (Naph)- and benzo(a)pyrene (B(a)P)-type metabolites, by fixed wavelength fluorescence detection (FF); (4) liver DNA strand breaks, erythrocytic micronuclei (EMN), and erythrocytic nuclear abnormalities (ENA) as genotoxicity parameters. Both SF-STIUE dilutions (0.1% and 1%) failed to significantly increase liver EROD activity, despite a significant increase of liver P450 at 16 and 48 h exposure to 0.1%. Liver GST activity increased significantly at 4h of sea bass exposure to 1% SF-STIUE, being inhibited at 96 h of exposure to this SF-STIUE dilution. Naph- and B(a)P-type metabolite contents were not significantly increased in bile. However, Naph-type metabolite contents increased significantly in liver cytosol at 4h exposure to 1% SF-STIUE, and at 24h exposure to 0.1% and 1% SF-STIUE. Furthermore, B(a)P-type metabolites increased significantly in liver cytosol at 4h exposure to 1% SF-STIUE, and 16 h exposure to 0.1% and 1% SF-STIUE. EMN and ENA frequencies increased significantly at 4, 8, 16, 24, 48, and 96 h exposure to 0.1% and 1% SF-STIUE. Liver DNA integrity decreased significantly at 96 h of sea bass exposure to 1% SF-STIUE. The STIUE discharged into Aveiro coastal area is of great ecotoxicological concern due to its genotoxic potential.     

Levels of certain metals, organochlorine pesticides and dioxins in cord blood, maternal blood, human milk and some commonly used nutrients in the surroundings of the Aral Sea (Karakalpakstan, Republic of Uzbekistan)

Since the 1960s a massive decline in the volume of the Aral Sea has occurred as a result of the diversion of the supplying rivers to cotton irrigation schemes. The contaminated sediment of the former seabed has been disseminated over the surrounding area by strong winds. This deterioration of the ecosystem has created a hazardous situation for the health of approximately 3.5 million people. This pilot study was undertaken to assist Karakalpak health workers in investigating the degree of exposure to metals, persistent organochlorine pesticides (OCPs) and dioxins during the most vulnerable prenatal and postnatal period and to provide guidelines for future research. All subjects came from areas located within 200 km of the southern border of the Aral Sea. Blood was obtained from 18 pregnant women and 28 newborns (cord blood) to determine the levels of metals, lead, cadmium, zinc and selenium and the OCPs alpha-, beta- and gamma-hexachlorocyclohexane (HCH; lindane is the product name of gamma-hexachlorocyclohexane), hexachlorobenzene (HCB), and isomers and metabolites of dichlorodiphenyltrichloroethane (DDT), i.e. op-DDT, pp-DDT, pp-DDE and pp-TDE. Levels of metals were also determined in blood from 28 non-pregnant women. In addition, levels of 17 dioxins were determined in 41 human milk samples and 1batch of formula. Information about possible dietary sources of the fat-soluble OCPs and dioxins was obtained from a pooled sample of butter and from seven cottonseed oil samples. A mass-selective detector coupled to a gas chromatograph equipped with a large volume injector was used to analyse the selected OCPs, whereas the dioxins were determined by gas chromatography with high-resolution mass spectrometry. The levels of metals in cord and maternal blood were consistent with concentrations observed in European countries. Only three women (7%) had lead levels greater than 100 ppb. The most notable pollutants in maternal and cord blood were the OCPs, notably HCB, beta-HCH, pp-DDE and the most toxic dioxin, 2,3,7,8-TCDD, when calculated as TEQs. A similar pattern was observed in human milk: beta-HCH and pp-DDE levels of more than 1,000 ng g(-1) fat were found in 68 and 43% of the subjects, respectively. Levels of 2,3,7,8-TCDD were six times higher than those observed in Western Europe. Traces of pp-DDE were detected in the batch of formula milk. Contaminated animal fat, but not cottonseed oil, is the most likely dietary source of OCPs and dioxins. CONCLUSION: Further epidemiological research is needed to elucidate the health implications of these pollutants on perinatal and maternal health, including lactation. More importantly, an investigation should be initiated to identify the emission sources of persistent organic pollutants in Karakalpakstan and adjacent regions.     

Time-dependent accumulation of cyanobacterial hepatotoxins in flounders (Platichthys flesus) and mussels (Mytilus edulis) from the northern Baltic Sea

There is only limited information about the accumulation of algal toxins in aquatic organisms in the Baltic Sea. In this study we measured total cyanobacterial hepatotoxin levels in blue mussel (Mytilus edulis) and flounderi (Platichthys flesus) tissues. Flounder were caught with gillnets from the western Gulf of Finland during July and August 1999. Blue mussels were collected from an enclosure at 3 m depth and from an artificial reef (wreck, 25-35 m depth) in the western Gulf of Finland between June and September 1999. Flounder liver and muscle samples and soft tissues of mussels were analyzed for the cyanobacterial hepatotoxins (nodularin, NODLN and/or microcystins, MCs) using an enzyme-linked immunosorbent assay (ELISA). Results showed a time-dependent accumulation of hepatotoxins in flounder and mussels. In flounder, the maximum concentration 399 +/- 5 (sd) ng NODLN or MC/g dry weight (dw) was found in the liver of specimens caught on 21 August 1999. No hepatotoxins were detected in muscle samples. The maximum concentration of 2150 ng +/- 60 (sd) ng hepatotoxin/g dw was found in the mussel soft tissues collected on 20 August 1999. Temporal NODLN or MC trends indicated depuration of cyanobacterial hepatotoxin from mussels at surface level and an increase in NODLN or MC concentrations in those from the sea bed. These studies showed that despite the low cyanobacteria cell numbers the cyanobacterial hepatotoxins can accumulate in flounder and mussels. This may allow the further transfer of cyanobacterial hepatotoxins in the food web.     

多种方法同步检测海产品中甲型副伤寒沙门菌的应用

目的：为查找食源性甲型副伤寒的病因,提高检出率.方法：采用国标法、mini VIDAS仪器法和PCR 3种方法同步检测11种生吃、半生吃海产品中甲型副伤寒沙门菌.检出菌株用VITEK32全自动微生物分析系统鉴定以及血清分型.结果：mini VIDAS仪器法和PCR 2种方法从1份牡蛎样品中检测出甲型副伤寒沙门菌,检出率为0.73%.结论：多种方法同步检测有利于提高生吃、半生吃海产品中甲型副伤寒沙门菌和沙门菌的检出率.用mini VIDAS或/和PCR过筛检测,具有简便快捷、灵敏度高的特点,阳性时再用国标法分离,可及时获得菌株,以提高检测工作效率,值得应用,尤其适用于杂菌量较多、目标菌易被掩盖以及不适宜甲型副伤寒沙门菌和其它沙门菌生长的样品.     

南海某礁作业人员健康及患病情况动态分析

目的探讨南海群礁作业人员在礁期间身体状况及患病情况动态变化规律,为制定合理医疗卫生保障方案提供依据。方法制定统一表格,由经过统一培训的医务人员连续90d每日逐人逐项当面询问、测量、记录相关内容。其中的指数指标采用视觉模糊评分法。结果随着在礁时间的延长,作业人员体重逐渐增加,至第11周时达最高水平,平均增加0.82kg（P〈0.01）。体能指数、健康指数、食欲指数及睡眠指数逐渐降低,睡眠时间逐渐减少,性唤起总人数比例逐渐降低,对自身健康的关心程度也逐渐降低（P〈0.01）。患病及用药人次数以上礁后的前3周较多,此后呈波浪式逐渐减少,第6周和第10周分别降至低谷,减少幅度尤以患病人次数明显（P〈0.01）。疾病变化趋势为呼吸系统疾病所占比例逐渐降低,消化系统疾病所占比例逐渐增加,皮肤疾病和运动系统疾病分别于第7,8周时较多;腹泻比例逐渐减少,便秘比例则逐渐增多。结论在礁3个月期间,作业人员身体状况和对自身健康的关心程度逐渐降低,患病和用药人次数呈波浪式逐渐减少。     

Characterization of 27-hydroxy-13-desmethyl spirolide C and 27-oxo-13,19-didesmethyl spirolide C. Further insights into the complex Adriatic Alexandrium ostenfeldii toxin profile

Alexandrium ostenfeldii is a widespread toxic dinoflagellate that has recently bloomed across the Adriatic Sea, seriously threatening both shellfish consumers and aquacultures. In 2007 we reported on preliminary studies carried out on field samples and cultures of A. ostenfeldii. At the time, along with three major spirolides – among which 27-hydroxy-13,19-didesmethyl spirolide C (3) proved to be a novel compound – a number of new minor spirolides were detected. Unfortunately, for all of them only Mass Spectrometry-based structural hypotheses could be ventured due to their very small amount. In the present paper we report on isolation and High Resolution Mass Spectrometry- and NMR-based structural elucidation of two of those minor spirolides detected in our previous study.