Comparison between "Yusho" patients and healthy Japanese in contamination level of dioxins and related chemicals and frequency of sister chromatid exchanges

Highly toxic organochlorine chemicals such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (CoPCBs) were determined in the peripheral blood and sebum from the face of 16 "Yusho" patients of about 27 yr after the outbreak of Yusho accident, and 39 healthy Japanese people. The mean total toxic equivalent (TEQ) levels of PCDDs, PCDFs and CoPCBs in the blood were still about seven times higher in Yusho patients than in healthy Japanese at the age of 45 yr and more. The sebum excretion of these chemicals seemed proportional to their blood levels in Yusho patients. These toxic chemicals, however, did not enhance frequencies of sister chromatid exchanges (SCEs) in the control and 7,8-benzoflavone (ANF) treated cultures in Yusho patients. Hence, no significant difference was observed in the mean SCE rates between the Yusho patients and general Japanese people of more than 45 yr of age. In this study, the number of Yusho patients examined is limited, so further large-scale investigations are needed to get more conclusive results concerning the genotoxic potency such as SCE induction.     

Determination of photosynthetic pigment composition in an individual phytoplankton cell in seas and lakes using fluorescence microscopy; properties of the fluorescence emitted from picophytoplankton cells

To develop a method for the determination of photosynthetic pigment species in individual phytoplankton cells, especially natural picophytoplankton cells, the fluorescence spectra of intact cells were studied with cultured phytoplankton. The study was made mainly with phycoerythrin-containing picophytoplankton collected off Japan in 1982 with reference to diatomal species and phycoerythrin-free cyanophycean species. The spectra were measured for cell suspensions with an ordinary spectrofluorometer, and for individual cells with a microscope spectrofluorometer, paying special attention to the effect of cell-fixation. Results indicated that: (1) the cell-fixation with the glutaraldehyde and paraformaldehyde mixture modified phycoerythrin emission from picophytoplankton markedly in its wavelength location and intensity, but (2) the emission from phycocyanin was affected far less, and (3) the emission from chlorophyll a was not altered. However, the phycoerythrin emission modified by the fixation was found to be easily distinguished from other emissions, and kept its intensity high enough for detection with a fluorescence microscope. The fluorescence properties after the fixation were kept unaltered for a long period of time. Based on the results, we propose a simple method for the determination of photosynthetic pigments in individual phytoplankton cells in seas and lakes using fluorescence microscopy. Results of our tests with natural samples of phytoplankton are presented, and problems for further improvement are also discussed.     

Accumulation of endocrine disrupting chemicals (EDCs) in the polychaete Paraprionospio sp. from the Yodo River mouth,Osaka Bay,Japan

This study presents the levels of endocrine disrupting chemicals (EDCs) accumulated by Paraprionospio sp. from the Yodo River mouth, Osaka Bay. Since high concentrations of nonylphenol (NP), bisphenol A (BP), octylphenol (OP), 17β-estradiol (E2), and estrone (E1) have been measured in sediment from Osaka Bay, some bioaccumulation could be expected particularly in benthic animals. EDCs were analysed in Paraprionospio sp., a dominant benthic species in Osaka Bay. The results showed that Paraprionospio sp. had accumulated varying concentrations (wet weight; w.w.) of NP at 1,460–4,410 ng/g; BP at 22.5–39.6 ng/g; OP at 18.9–45.4 ng/g; E2 at 0.89–4.35 ng/g; and E1 at 0.06–2.50 ng/g. Accumulation of NP and OP were highest among the samples gathered in summer (July 2008), while concentrations of BP, E2, and E1 did not much differs within 3 years. EDC levels in Paraprionospio sp. were apparently greater than those in sediments showing bioaccumulation.     

Mitigation of peroxidative stress for barley exposed to cadmium in the presence of water-extractable organic matter from compost-like materials

The effects of water-extractable organic matter (WEOM) from compost-like materials on peroxidative stress were investigated for hydroponic culture of barley exposed to Cd. In the presence of WEOM, lipoxygenase activity and malondialdehyde, indices of peroxidative stress in barley, were significantly reduced, compared to those with Cd alone (5 μM) for a 30-d culture (p < 0.05). In addition, Cd uptake in the presence of WEOM samples was significantly lower than that in their absence (p < 0.05). These results indicate that the addition of WEOM can be effective in mitigating the peroxidative stress in barley exposed to Cd. Of the total Cd in the solution, 7–8% was complexed with WEOM, indicating that the complexation of Cd with WEOM is a minor factor in reducing Cd-induced stress in barley. The WEOM sample was purified by cation-exchange column and ultrafiltration to remove the nutrient minerals, such as Ca, Mg and Fe. When the purified WEOM was employed for hydroponic culture in the presence of Cd, significant decreases in peroxidative stress and Cd uptake were observed (p < 0.05). These results show that the organic components in WEOM contribute to the mitigation of peroxidative stress in barley exposed to Cd.     

Secondary polygyny by inbred wingless sexuals in the dolichoderine ant Technomyrmex albipes

Summary Technomyrmex albipes makes huge polydomous colonies which consist of up to several millions of adults. In field colonies, dealate queens are rare or absent, though winged males and winged females emerge annually (synchronously) in large numbers from late may to mid June. Field and laboratory observations showed that the reproduction of established colonies was performed by wingless females inseminated by wingless males from the same colony. Dissections and morphological examinations revealed that wingless females are workers with no spermatheca and intercastes with a spermatheca. Most intercastes were inseminated, had developed ovaries, and seemed to reproduce, while workers did not seem to reproduce. Extranidal tasks were performed only by workers. Approximately half of the adult population were intercastes, and wingless males represented only a small portion of all adults, the rest being nonreproductive workers. Intercastes and wingless males were produced throughout the year except in winter. The winged females and males copulate outside the nest only after the nuptial flight and the dealate females are able to perform independent founding, but they are also eventually supplanted by intercastes. The adoption of dealate queens by an established natal colony did not seem to occur. Thus we infer that in this species the winged reproductives disperse and found new colonies, while inbred wingless reproductives allow the enlargement and budding of colonies. This species has a special trophic-flow system. There is no trophallaxis among adults, and nutrient transfer from adults to other colony members is achieved exclusively by specialized trophic eggs. All females (dealate queens, intercastes, and workers) seem to produce trophic eggs. This aphid-like life cycle, i.e., the occurrence of both winged and wingless reproductive forms, may have evolved as an adaptation supporting the development of secondary polygyny and polydomy.Offprint requests to: K. Yamauchi     

Latitudinal trends in size-dependence of bioluminescence in the midshipman fish Porichthys notatus

The bioluminescent fish Porichthys notatus (plainfin midshipman), has a discontinuous distribution along the Pacific coast of North America. The fish is present from Cape Mendocino southward to Baja California, Mexico, absent off the coast of Oregon, USA, and abundant, northward, in Puget Sound, Washington. Interestingly, the population in Puget Sound lacks the substrate (luciferin) necessary for the luminescence reaction and, despite possessing an otherwise fully functional photophore system, is nonluminescent. The California population of P. notatus is uniformly luminescent south of Monterey Bay, but 15% of the speciments tested from San Francisco Bay and the Gulf of the Farallons have been reported to be nonluminescent. Explanations for nonluminescent midshipman in both Puget Sound and the San Francisco Bay area have focussed on a dietary requirement for luciferin. To gain further insight into reasons for nonluminescence in the San Francisco Bay region, the distribution of bioluminescence in P. notatus was studied from Monterey Bay to Cape Mendocino during 1985. A complex pattern of bioluminescence was found, in which nonluminescent individuals reflected neither a local anomaly in the San Francisco Bay region nor a simple gradient of decreasing luminescence towards the northern end of the range of the California population. Instead, a distinct size-dependent component in luminescence capability of the fish was observed. Aspects of the life history of P. notatus and related factors which might influence the bioluminescence characteristics of this population are discussed.Please address all correspondence to Dr. F.I. Tsuji at the Osaka Bioscience Institute     

A probabilistic hazard and risk assessment of exposure to metals and organohalogens associated with a traditional diet in the Indigenous communities of Eeyou Istchee (northern Quebec,Canada)

Environmental Science and Pollution Research - Hunting, trapping, and fishing are part of an Indigenous lifestyle in subarctic Canada. However, this lifestyle may be a route of exposure to...     

Community vulnerability to changes in the winter road viability and longevity in the western James Bay region of Ontario’s Far North

Regional Environmental Change - A network of winter roads that consists of snow-ice roads over land, muskeg, and frozen lakes and rivers has been and continues to be a critical seasonal lifeline in...     

A study on the self-assembly behavior of dark materials from molasses

We have previously demonstrated that dark materials (DM) in acidified molasses are effectively adsorbed to Amberlite XAD7HP resin and are eluted from the resin with 0.1 M sodium hydroxide. In this paper, we have characterized the self-assembly behavior of molasses DM by using dynamic and static light scattering in combination with isoelectric focusing and infrared absorption spectroscopy in order to better understand the resin adsorption mechanism. One of DM derivatives, X-G2, contained carboxyl and hydroxyl groups and had a weight-average molar mass of 9.39?×?10³ to 4.42?×?10⁴ at pH 2.1–11.5. The aggregates retained their spherical shape over the full pH range and the large gyration radius (66.4–80.0 nm) indicated that the inner structure was loosely packed. Furthermore, X-G2 had an isoelectric point of 1.8, and its density increased sharply at pH 5.9 and then approached a nearly constant value under alkaline conditions. In summary, the self-assembly processes of DM are controlled by intermolecular hydrogen-bonding and hydrophobic interactions. The aggregates adsorb to the resin through hydrophobic interactions and are eluted when excess carboxylate anions are generated.     

Fixation of methylene-blue-treated nervous tissue for histological and ultrastructural studies

The Science of Nature -