Harumi Kojima

Uptake, distribution, and elimination of sodium linear alkylbenzene sulfonate and sodium alkyl sulfate in carp.

Uptake, distribution, and elimination of labeled surfactants, 35S-labeled sodium laurylbenzenesulfonate (35S-C12-LAS) and 35S-labeled sodium lauryl sulfate (35S-C12-AS), were investigated in carp exposed to a low concentration level of the respective solutions found in river water in Japan by whole-body autoradiography and liquid scintillation counting. Whole-body autoradiograms showed that the fish absorbed 35S-C12-LAS and 35S-C12-AS from the solutions principally through gills and that the surfactants absorbed were rapidly distributed throughout the body tissues and organs. High concentrations were found in gills, blood, hepatopancreas, kidney, and gall bladder. The elimination in the fish that were kept in clean fresh water after exposure were relatively rapid in most tissues and organs except for gall bladder. These results suggest that the surfactants absorbed in fish may have an adverse effect on many tissues and organs of fish. What influenced the distribution profile and concentration factors of the surfactants in tissues and organs of carp were the exposure time and the molecular structure of the surfactants.

On the photolysis of alkylated naphthalenes in aquatic systems

Abstract The photodegradability in aquatic systems of some alkylated naphthalenes and related compounds was studied using a high-pressure mercury lamp. The rate constant and half-life of their degradation were estimated in distilled water. From the results performed in artificial seawater, which served as a marine environmental model, the rate of photolysis of alkylated naphthalenes increased several times over that in distilled water. This was especially observed for naphthalene. Therefore, sodium chloride, the main component of seawater, was estimated to be the cause of the enhancement, because the rate increased nearly proportionally to the concentration of NaCl in the system, with a correlation coefficient of 0.995 for 2-isopropylnaphthalene.

Effect of alkyl chain on the uptake, distribution, and excretion of 35S-labeled alkyl sulfates in carp.

Abstract The effect of the number of carbons of the alkyl chain on the uptake, distribution, and excretion of a surfactant in fish was investigated using 35S-labeled alkyl sulfates (35SAS) of three different carbon numbers and carp. As a result, the radioactivity was found to be easily taken up into the fish body and distributed throughout the tissues and organs for any surfactant, but the concentration factors differed characteristically depending upon the number of carbons of the alkyl chain, i.e., 2.1, 11, and 73 for 35S-labeled sodium lauryl sulfate (35S-C12-AS), 35S-labeled sodium myristyl sulfate (35S-C14-AS), and 35S-labeled sodium cetyl sulfate (35S-C16-AS), respectively. And the distribution profile and excretion rate also tended to be affected by the number of carbons of the alkyl chain.

Studies on environmental safety of di-isopropylnaphthalene (DIPN) part-I bioconcentration of 14C-DIPN in carp

Chlorinated hydrocarbons, particularly dichlorodiphenyl trichloroethane (DDT) and polychlorinated biphenyls(PCBs), have been widely found in the environment due to their persistency i.e. chemical and biological stability. Recently, the production and usage of PCBs was strictly regulated and the usage in the open system was prohibited in many countries. The solvent for carbonless paper, which was one of the main use of PCBs has been replaced by the aromatic hydrocarbons which contain no halogens. Diisopropylnaphthalene (DIPN) (Fig.l) has been widely used as one of the substitutes for PCBs. Kawai(1) reported the distriFig.] Syntheses of LabelJed Compounds bution and excretion of 3H-DIPN in mice and the bioaccumulation of 3H-DIPN 3H-DIPN in carp and gray --R2 R2 /CH3

Bioaccumulation profiles of 35S-labelled sodium alkylpoly(oxyethylene) sulfates in carp (Cyprinus carpio)

Abstract The uptake, distribution and elimination of two labelled surfactants, 35S-labelled sodium dodecyltri(oxyethylene) sulfate (35S-C12-AES(3)) and 35S-labelled sodium dodecylpenta(oxyethylene) sulfate (35S-C12-AES(5)) were investigated in carp (Cyprinus carpio) exposed to concentrations of 0.3–0.6 mg l−1, using whole-body autoradiography and the liquid scintillation counting method. 35S-Radioactivity was first rapidly absorbed by the gills and skin and transferred to other organs and tissues. After 24 h-exposure, there was a comparatively high accumulation of 35S-radioactivity in the gills, hepatopancreas, gall bladder, intestinal content, and nasal and oral cavity. The distribution patterns of 35S-radioactivity derived from 35S-C12-AES(3) and 35S-C12-AES(5) in tissues and organs were similar. The whole-body concentration factors of 35S-radioactivity in fish exposed to 35S-C12-AES(3) and 35S-C12-AES(5) for 72 hr were 18 and 4.7, respectively. In surfactant-free water, the absorbed 35S-radioactivity was eliminated more rapidly from the fish body exposed to 35S-C12-AES(3) than 35S-C12-AES(5). It was eliminated relatively fast from gills and hepatopancreas, but elimination from gall bladder was rather slow.

Identification of 2,6-diisopropylnaphthalene metabolites in carp part 1. In vivo experiment

Abstract The metabolism of diisopropylnaphthalene (DIPN) in fish was studied from an ecotoxicological viewpoint to clarify the environmental fate of DIPN, a solvent of carbonless paper which is widely used as a substitute for PCB. This study identified the following metabolites in carp by in vivo experiment; 2-(1-hydroxy-1-methyl) ethyl-6-isopropylnaphthalene, 2-(1-methyl-2-hydroxyethyl)-6-isopropyl-naphthalene, 2,6-(1-hydroxy-1-methyl) ethyl-naphthalene, 2-(1-hydroxy-1-hydroxymethyl) ethyl-6-isopropylnaphthalene and α-[2-(6-isopropylnaphthyl)] propionic acid. Identification was based on UV, IR, MS, and NMR analyses. The metabolism of 2,6-DIPN in carp was concluded to mainly through oxidation of the isopropyl chain.

Studies on the sequence of 2,6-diisopropylnaphthalene metabolite formation using carp hepatocyte.

Metabolism of 2,6-diisopropylnaphthalene (2,6-DIPN) was studied in freshly isolated carp hepatocytes with special reference to cytochrome P-450-mediated oxidation. The viability of isolated hepatocytes obtained by use of Ca2+-free and collagenase-containing Hanks buffer was 93%, judging from both trypan blue penetration and lactic dehydrogenase (LDH) leakage. 2,6-DIPN was metabolized to form several oxidized products such as the tertiary hydroxy, the primary hydroxy, and two types of dihydroxy DIPN. From the results of the time course experiments, it was assumed that 2,6-DIPN was hydroxylated primarily on the tertiary and primary positions of the isopropyl group, respectively, and thereafter was converted to tertiary-tertiary and primary-tertiary hydroxylated products. These assumptions are supported by results obtained previously in in vivo and in vitro studies.

Distribution and accumulation of [2,3-14C]acrylonitrile in rat after single injection☆

The distribution and accumulation of acrylonitrile after the single i.p. injection of [2,3-14C]acrylonitrile were examined by whole-body autoradiography and by the determination of 14C radioactivities in several tissues and subcellular fractions after a whole-body perfusion. 14C Radioactivity was seen strongly in blood, particularly in red blood cells, and in several tissues including lung, liver, and kidney. Longer retention of radioactivity in brain and muscle was observed. At the subcellular level a relatively high specific radioactivity was seen in cytosol fractions of the brain, liver, and kidney.

Evaluation of the effect of chemicals on aquatic ecosystem by observing the photosynthetic activity of a macrophyte, Porphyra yezoensis

Abstract Photosynthetic activity of a macrophyte, Porphyra yezoensis , was observed after exposure to chemicals in order to establish a method for evaluating their effects on the ecosystem. Both carbon assimilation and extracellular products were measured using [ 14 C]Na 2 CO 3 . Commonly used herbicides, (1-(3,4-dichlorophenyl)-3,3-dimethylurea (DCMU), pentachlorophenol (PCP) and 3-amino-1H-1,2,4-triazol (amitrole), were tested. Photosynthesis was inhibited by DCMU and PCP, and EC 50 values were estimated to be 0.009–0.014 and 5.4–5.5 ppm, respectively. However, no significant inhibitory effect was observed with amitrole. Extracellular products showed an exponential increase in the cases of DCMU and PCP, similar to that observed in photosynthesis. Thus, the inhibitory effects of chemicals on the photosynthetic activity of Porphyra can be quantitatively observed using this method.

Metabolites of diisopropylnaphthalene in carp Part 2. In vitro experiment

Abstract This study described an in vitro experiment on biotransformation of 2,6-DIPN in carp hepatopancreas. It has already been revealed by the previous in vivo studies to be metabolized with enzymatic oxidation in the liver and been postulated a metabolic pathway. These results were confirmed by means of incubation with 2,6-DIPN in carp hepatic microsome preparation with NADPH, and G-6-P as co-factor. It was suggested that DIPN may be mainly metabolized in the hepatic cytochrome P-450 in the microsomes system. The kinetic parameters i.e. apparent Michaelis constant (Km) and maximum velocity (Vmax), in the metabolites formation were also calculated.