Green Gland Research Articles

Carapace microbiota in American lobsters (Homarus americanus) associated with epizootic shell disease and the green gland.

Epizootic Shell Disease (ESD) has posed a great threat, both ecologically and economically, to the American lobster population of Long Island Sound since its emergence in the late 1990s. Because of the polymicrobial nature of carapace infections, causative agents for ESD remain unclear. In this study, we aimed to identify carapace microbiota associated with ESD and its potential impact on the microbiota of internal organs (green gland, hepatopancreas, intestine, and testis) using high-throughput 16S rRNA gene sequencing. We found that lobsters with ESD harbored specific carapace microbiota characterized by high abundance of Aquimarina, which was significantly different from healthy lobsters. PICRUSt analysis showed that metabolic pathways such as amino acid metabolism were enriched in the carapace microbiota of lobsters with ESD. Aquimarina, Halocynthiibacter, and Tenacibaculum were identified as core carapace bacteria associated with ESD. Particularly, Aquimarina and Halocynthiibacter were detected in the green gland, hepatopancreas, and testis of lobsters with ESD, but were absent from all internal organs tested in healthy lobsters. Hierarchical clustering analysis revealed that the carapace microbiota of lobsters with ESD was closely related to the green gland microbiota, whereas the carapace microbiota of healthy lobsters was more similar to the testis microbiota. Taken together, our findings suggest that ESD is associated with alterations in the structure and function of carapace microbiota, which may facilitate the invasion of bacteria into the green gland.

<p><strong><em>Zehneria monocarpa</em></strong><strong> (Cucurbitaceae), a new species from the relicts of Kenya’s coastal forests</strong></p>

Zehneria monocarpa (Cucurbitaceae), a new species from the fragmented lowland coastal forests of Kenya is described here and illustrated with photographs. It resembles Z. oligosperma and Z. longiflora, but can be distinguished by its solitary female flowers and fruits. Furthermore, the new species has 1–23 conspicuous dark green glands on the apex of the leaf and the inner part of its receptacle tube is entirely hairy.

Effects of freshwater crayfish on influenza A virus persistence in water.

Several investigations have recently assessed the ability of some aquatic invertebrates to act as tools for avian influenza A virus (IAV) surveillance as well as their potential role(s) in IAV ecology. Because of this, as well as the high IAV seroprevalence rates noted in select mesocarnivores that commonly inhabit aquatic and semi-aquatic habitats, we evaluated the effects that freshwater crayfish have on IAV in water at three dose levels and monitored for the presence of IAV in crayfish tissues (gill and green gland) and haemolymph at multiple time points. At relatively high, medium and low (approximately 104 , 103 and 102 EID50 /ml, respectively) doses, mesocosms containing crayfish (Orconectes sp.) had less detectable IAV RNA present when final water samples were assayed (9days post-contact [DPC]). In general, containers without crayfish present had nearly three-fold greater quantities of viral RNA at 9DPC. A varying number of RNA positive samples were detected for the three crayfish sample types collected. Gill tissue produced the largest number of positive non-water samples (n=26), with the highest quantities detected from crayfish sampled on 1 and 4DPC (103.5 EID50 equivalent/ml). On a few occasions, gill (n=8) and haemolymph samples (n=1) produced higher quantities of viral RNA than their respective water samples or water samples collected 1-2DPC earlier, but these differences were typically minor. Based upon water samples, statistical models indicated that the interaction of dose and crayfish exposure days explained most of the variation in these data. Future efforts should address if crayfish exposed to IAV-laden water have the capacity to successfully transmit IAVs to mammals and birds which frequently prey upon them.

Effects of titanium dioxide nanoparticles on red swamp crayfish, Procambarus clarkii: Bioaccumulation, oxidative stress and histopathological biomarkers

The widespread use of titanium dioxide nanoparticles (TiO2 NPs) in many applications has led to its significant release to aquatic systems. Hence, the present study was performed to evaluate effects of TiO2 NPs on crayfish Procambarus clarkii, which is often used as a bioindicator of water pollution. Adult male specimens were treated with 25, 125, and 250 mg/l of TiO2 NPs for 28 days. Mortalities were 0, 3.3, and 10% for animals treated with 25, 125, and 250 mg/l of TiO2 NPs, respectively. The level of titanium bioaccumulation in different tissues was as follows, gills > hepatopancreas > green glands > muscles. TiO2 NPs-exposed crayfish showed significant increase in the levels of catalase, glutathione-S-transferase, glutathione peroxidase, gamma-glutamyl transferase, glutathione, and metallothioneins in the hepatopancreas. Exposure of the crayfish to 250 mg/l TiO2 NPs caused severe histopathological alterations. In the hepatopancreas, the most prominent pathological changes were tubular disruption and inflammatory infiltration. Under transmission electron microscope (TEM), ruptured microvilli, deformed mitochondria and fragmentation of rough endoplasmic reticulum (RER) were observed. In the gills, swelling of gill lamellae, disorganization and degeneration of epithelial cells were noted under the light microscope (LM). Under electron microscope (EM), gills of crayfish treated with 250 mg/l TiO2 NPs showed vacuolation, dense granules, and diminution in the number of apical plasma membrane infoldings. In conclusion, TiO2 NPs caused alteration in antioxidant activities and severe histopathological changes.

Impact of ions of zinc and cadmium on body weight, fertility and condition of the tissues and organs of Procambarus virginalis (Decapoda, Cambaridae)

Heavy metals cause functional disorders in the tissues and organs of hydrobionts, affecting their linear-weight indicators, reproductive system, digestive and eliminative organs. Using the method of histological estimation of the conditions of the tissues and organs of Procambarus virginalis Lyko, 2017 allowed us to determine the peculiarities of adaptation of crustaceans to the effect of different concentrations of heavy metal ions in the conditions of a modeling experiment. We studied the impact ions of zinc (0.1 mg/l) and cadmium (0.01 mg/l) on the organism of P. virginalis. The heavy metal ions had a negative effect on the weight indicators, survivability and reproduction of P. virginalis. During the experiments with zinc, we observed death of 18.2% of the tested сrustaceans; the highest death rate was observed in the experiment with cadmium – 27.3%. Experimentally modeled concentrations of heavy metals negatively affected the reproductive system of P. virginalis. In the experiment with cadmium ions, we observed no spawning; the highest percentage of the females with deposed eggs was observed in the control – 29.1%. The conducted studies allowed us to observe the reaction of the eliminatory system of P. virginalis to the impact of heavy metal ions. The impact of ions of zinc and cadmium decreased the area of secretory cells of the green gland by 10.4–14.8%. We observed grinding of the nuclear cell apparatus. Therefore, the nucleii of granulocytes were 23.6% smaller under the impact of zinc, and 17.5% smaller under the influence of cadmium. The sizes of cells and nucleus apparatus decreased mutually and proportionally; this was proven by stable indicators of nucleus-cytoplasm ratio, its value equaled 0.29–0.31 units. The given concentrations of heavy metals did not affect the histological condition of the adipose tissue, the sizes of adipocytes fluctuated within the range of 215–2178 μm2, the average equaled 872–994 μm2. We determined the negative effect of heavy metals on the histological structure of the hepatopancreas and the value of gland lumens. In the control, the area of previous section equaled 164.5 μm2 with 39 μm2 lumen. During the experiment with zinc ions the structures of hepatopancreas increased by 19.9%, and in the experiment with cadmium, we observed the highest increase in the structural elements of the tissues – by 50.2%. The worst histological condition of the cells of the tested tissues and organs of P. virginalis was observed among individuals impacted by the cadmium ions; this is explained by the high toxic effect of this heavy metal.

Features of histological adaptation of Marbled crayfish Procambarus fallax f. virginalis (Decapoda) to the different concentration of cadmium ions in model experiment

The article shows the results of studies on the influence of cadmium ions on the histological structure of antennal gland cells of marbled crayfish Procambarus fallax f. virginalis Martin et al., 2010 (Decapoda). Due to the fact that marbled crayfish got into the reservoirs of the Dnipropetrovsk region in 2015, it was necessary to study the possibilities of its adaptation to environmental factors of reservoirs for further prediction of its distribution or even acclimatization under conditions of toxicological contamination of the ponds of the steppe Prydniprovya. We conducted a laboratory model experiments to study the mechanisms of adaptation of marbled crayfish Procambarus fallax f. virginalis. The effect of different concentrations of cadmium ions (0.01 mg/l, 2 MРC) on physiological state and histostructure of the excretory system of marbled crayfish was determined. The cells of the antennal gland of marbled crayfish in the control had a size of 166.08 ± 10.13 μm2. Glandulocytes had clear cells edges, pronounced structure of ducts, and a clear basal membrane. The cells had large nuclei with a cross-sectional area of 51.31±3.92 μm2. The nucleic membrane had clear edges, there were nucleoli in nuclei that were characterized by basophilia. That is, the structure of the antennal gland of marbled crayfish in control was normal for Decapods. The worst histological picture of antennal gland cells was observed in individuals exposed to cadmium ions. The structure of the excretory ducts of the green gland was broken, they had fuzzy boundaries, contained a large number of fragments of glandulocytes cytoplasm. In some cells there was a picnose of nuclei, as well as the output of a nucleolus beyond the nucleus which is the appearance of the micronucleus. This phenomenon is caused by the toxicological effects of cadmium. Compared with control, the glandulocytes of the antennal gland were 14.8 % smaller, their area of cross-section reached 141.44±7.60 μm2. The nuclei of the glandular cells were also significantly lower by 17.5 % than such in control, and their area reached 42.32±1.74 μm2. To study the influence of cadmium on the glandular cells of the green gland of marbled crayfish, the index of nuclear-cytoplasmic ratio (NCR) was used. The indicator of nuclear-cytoplasmic ratio allows estimating the level of metabolism and detecting the manifestation of compensatory reactions of the organism of experimental crayfish. The value of NCR in the trial and control did not differ statistically and amounted to 0.31 units. This indicates an interproportional reduction in both the cytoplasm of the cells of the green gland and their nuclei, caused by cadmium exposure. It was determined that under the influence of heavy metals the size of the glandular cells and their nuclei decreases, while the nuclear-cytoplasmic ratio remains the same, which is probably an adaptive reaction of the excretory system against the influence of heavy metal ions. Investigation of the histological structure of tissues and organs of marbled crayfish will allow the development of measures for the determination of biomarkers for the bioindication of the aquatic environment using freshwater crayfish. The results of such studies have an important fundamental and applied significance for understanding the mechanisms of adaptation of crustaceans to the conditions of toxicological burden on aquatic ecosystems.

De Novo assembly and annotation of the freshwater crayfish Astacus astacus transcriptome

We generated RNA-seq data to assemble the transcriptome of the noble crayfish (Astacus astacus) from four combined tissues (abdominal muscle, hepatopancreas, ovaries, green glands). A total of 194 million read pairs with a length of 100 bp were generated. The transcriptome was assembled de novo using Trinity software, producing 158,649 non-redundant transcripts. Lowly expressed transcripts were filtered out leaving 45,415 transcripts of which 14,559 were found to contain open reading frames with predicted gene function. The Transrate software revealed that 91% of the total reads were realigned to the assembly. Furthermore, BUSCO analysis indicated that our assembly is 64% complete. A total of 13,770 transcripts were assigned at least one GO term. This first de novo transcriptome assembly is an important foundation for future genomic research on the noble crayfish and adds to the general knowledge and further characterization of transcriptomes of non-model organisms.

Are antioxidant and transcriptional responses useful for discriminating between chemo- and radiotoxicity of uranium in the crayfish Procambarus clarkii?

The main objectives of this study were to evaluate uranium (U) toxicity in the crayfish Procambarus clarkii at a low dose of exposure and to discriminate between the chemotoxicity and radiotoxicity of U. We conducted two sets of experiments using either 30μgL−1 of depleted uranium (DU) or 233U, which differ from each other only in their specific activity (DU=1.7×104Bqg−1, 233U=3.57×108Bqg−1). The endpoints were oxidative stress responses and mitochondrial functioning in the gills and hepatopancreas, which were measured in terms of enzyme activities and gene expression levels. U accumulation levels were measured in different organs (gills, hepatopancreas, stomach, intestine, green gland, muscles, and carapace), and internal dose rates in the hepatopancreas were compared after DU and 233U exposures. Significant U accumulation occurred in the organs of P. clarkii, and mitochondrial damage and antioxidant responses were detected. Despite the huge difference (21,000×) in the specific activities of DU and 233U, few significant differences in biological responses were detected in P. clarkii exposed to these two pollutants. This finding indicates that the radiotoxicity was low compared to the chemotoxicity under our exposure conditions. Finally, genes expression levels were more sensitive markers of U toxicity than enzyme activities.

The Fluorescent Pigment of Mulberry Transferred in the Body of Silkworm, <i>Bombyx Mori</i>

Using silkworm (Bombyx mori, Dazao strain) as material, the fluorescent pigment of mulberry, silkworm blood, silk gland, cocoon shell, silkworm excrement, silkworm urine and moth urine were analyzed by using the technology of thin layer chromatography (TLC). The results indicated that there were 7 bands of fluorescent pigment from the extracts of green cocoon shell after TLC analysis. While, 2 bands in silkworm blood and its urine extracts, 4 bands in the silk gland extracts, as well as 5 bands in moth urine extracts were detected, but no band detection in the silkworm excrement extracts. The blue-violet fluorescent pigment which has the same Rf (0.35) was detected from the extracts of green cocoon shell, silk gland, silkworm urine, moth urine and mulberry after TLC analysis, but it cannot be found in silkworm blood and silkworm excrement. It was revealed that the blue-violet fluorescent pigment may be transferred directly from mulberry leaves, and then accumulated in the silk gland. Most of the pigment remained in the cocoon shell. And only a small amount of this kind of pigment was excreted through urine. There was also some yellow-green fluorescent pigment detected in the silkworm blood, silk gland and cocoon shell extracts, but it cannot be detected in both the mulberry and silkworm urine extracts. It was suggested that yellow-green fluorescent pigment synthesis pathway exist in the body of silkworm (Bombyx mori, Dazao strain).

Trophic transfer of aluminium through an aquatic grazer–omnivore food chain

The potential for trophic transfer of aluminium (Al) was investigated using a grazing detritivore, the freshwater snail Lymnaea stagnalis, and a predator, the signal crayfish Pacifastacus leniusculus. Snails were exposed to either aqueous Al (500 μg l −1) in the presence or absence of an inorganic ligand (phosphate (+P); 500 μg l −1) for 30 days, or kept as unexposed controls. Subcellular partitioning of Al in the snail tissues was characterised using ultracentrifugation. Al content in the soft tissues and the subcellular fractions was measured using inductively coupled plasma atomic emission spectroscopy. Exposed and control snails were fed to individually housed crayfish ( n = 6 per group) over 40 days. Water samples, uneaten snail tissue and faeces were collected throughout the experiment in order to assess the fate of Al. Behavioural toxicity to the crayfish was assessed at four time points, and tissue accumulation of Al in soft tissues was measured following a 2-day depuration period. Snails exposed to Al + P accumulated more Al per snail than those exposed to Al only (291 μg vs 206 μg), and also contained a higher proportion of detoxified Al (in inorganic granules and associated with heat stable proteins) (39% vs 26%). There were no significant differences in behavioural activity between the different groups of crayfish at any time point. Crayfish fed snails exposed to only Al accumulated significant levels of Al in their total soft tissues, compared to controls; crayfish fed Al + P-exposed snails did not, even though concentrations of Al in these snails were higher. The highest concentrations of Al were found in the green gland in both crayfish feeding groups, and the gut and hepatopancreas in crayfish fed Al only exposed snails; all of these were significantly higher than in crayfish fed control snails. There was no significant accumulation of Al in the gills or flexor muscle in any group. At least 17% of trophically available Al in the snail tissues was accumulated by the crayfish. This proportion was similar in both feeding groups but, as the proportion of trophically available Al in the snails exposed to Al + P was lower, this led to lower accumulation in the Al + P crayfish feeding group. This study indicates that in comparison to vertebrates, aquatic invertebrates accumulate a higher proportion of Al via oral ingestion but it does not accumulate in tissues that may pose a threat to human consumers.

Identification of a Cytoplasmic Manganese Superoxide Dismutase (cMnSOD) in the Red Swamp Crawfish,Procambarus clarkii: cDNA Cloning and Tissue Expression

A cytoplasmic manganese superoxide dismutase (cMnSOD) cDNA was cloned from the hepatopancreas of the red swamp crawfish, Procambarus clarkii. An initial cDNA fragment was identified by using degenerate primers, and the complete sequence was obtained by using RACE methodology. The full sequence comprises 1140 bp, with an open reading frame of 858 bp encoding a protein of 286 amino acids. Sequence analysis showed that this protein is highly homologous to previously obtained crustacean cMnSODs. Phylogenetic analysis clusters it with all known cMnSODs and in a group distinct from mitochondrial MnSODs. cMnSOD transcripts were detected in the gills, tail muscle, green glands, and hepatopancreas. The data provide additional evidence for the hypothesis that cMnSOD replaced CuZnSOD in crustaceans that use haemocyanin as the respiratory pigment.

Bioaccumulation of Lead Nitrate in Freshwater Crayfish (Astacus leptodactylus) Tissues Under Aquaculture Conditions

The aim of this research was to evaluate the amount of lead in the tissue of Astacus leptodactylus especially in their muscle which the consumed part of their body. In this study the crayfish was exposed to intermediate concentration of lead nitrate (500 microg L(-1)) for periods up to 3 weeks. In the first, second and third weeks bioaccumulation in various tissues was under investigation. The data of toxicological analysis obtained by the method of atomic absorption revealed that the levels of bioaccumulation of metal are different in various tissues of this crayfish. The accumulation of the lead in gills was the highest and in muscles was lowest degree. The amount of heavy metals in the tissues of crayfish was as follow. Gills>exoskeleton>hepatopancreas (digestive glands)>digestive tract>green gland>testis and ovary>muscles.

EUPHORBIA GILBERTIANA: A NEW DISTINCTIVE DWARF SUCCULENT EUPHORBIA FROM SOUTHERN ETHIOPIA

Abstract We report the description of Euphorbia gilbertiana, a new, distinctive, dwarf succulent from Southern Ethiopia, found not far from the Somali border. Its carunculate seeds and four green glands ally this species most closely with members of section Eremophyton, such as E. pirottae. With its fleshy and compact habit, its long, lax rays and its almost glabrous habit, E. gilbertiana is clearly differentiated from the annual species E. pirottae.

UDPglucosyltransferase and its kinetic fluorimetric assay.

A rapid, kinetic assay for UDPglucosyltransferase has been developed using 1-naphthol as substrate. It is based on the continuous fluorimetric monitoring of 1-naphthyl glucoside formation during the reaction at physiological pH. The conjugate is easily distinguished from aglycone, since their fluorimetric properties differ. Glucoside biosynthesis in vitro by microsomal preparations isolated from the gut and fat body of cockroaches Periplaneta americana and Leucophaea maderae, and from the green gland and hepatopancreas of the crayfish Astacus astacus, has been demonstrated. The effects of buffer, pH, MgCl2, UDP-glucuronic acid, UDP-N-acetylglucosamine, sodium cholate and sonication on the enzyme activity have been assessed. The kinetic parameters of 1-naphthol and UDP-glucose have also been determined.

Purification and characterization of a mandibular organ protein from the American lobster, Homarus americanus: a putative farnesoic acid O-methyltransferase

Methyl farnesoate (MF) appears to have important roles in the development, morphogenesis, and reproduction of crustaceans. To better understand the regulation of MF synthesis, we studied farnesoic acid O-methyltransferase (FAOMeT, the final enzyme in the MF biosynthetic pathway) in the American lobster ( Homarus americanus). FAOMeT purified from mandibular organ (MO) homogenates had a MW of approximately 38,000. The sequences of trypsin fragments of purified FAOMeT were used to design PCR primers to amplify a cDNA fragment, which was used to isolate a full-length cDNA containing a single open reading frame (ORF) of 828 bp encoding a protein of 276 amino acids. The deduced amino acid sequence of this putative FAOMeT protein contained two copies of a conserved ~135 amino acid domain we term the CF (CPAMD8/FAOMeT) domain; single copies of this domain also occur in the human CPAMD8 protein (a member of the alpha-2 macroglobulin family) and an uncharacterized Drosophila protein. The recombinant protein had no FAOMeT activity. However, its addition to MO homogenates from eyestalk ablated (ESA) lobsters increased enzyme activity by up to 75%, suggesting that FAOMeT may require an additional factor or modification (e.g., phosphorylation) for its activation. The mRNA for the putative FAOMeT was primarily found in the proximal region of the MO, the predominant site of MF synthesis. FAOMeT transcripts were found in muscle tissue from ESA animals, but not in green gland, hepatopancreas, or in muscle tissue from intact animals. FAOMeT mRNA was also detected in embryos and larval stages. This is the first comprehensive report of this protein in the lobster, and is an important step in elucidating the functions of MF in these animals.

Simultaneous experimental study of direct and direct plus trophic contamination of the crayfish astacus astacus by inorganic mercury and methylmercury

An experimental study was carried out to investigate direct and direct plus trophic contamination routes of the crayfish Astacus astacus by inorganic mercury (Hg(II)) or methylmercury (MeHg). Direct exposure was based on low contamination conditions, 300 and 30 ng/L in the dissolved phase, respectively, during 30 d at 20 degrees C. Trophic exposure was based on daily consumption of the Asiatic clam Corbicula fluminea, previously contaminated during 40 d with similar exposure conditions. The Hg concentrations in the bivalves were very similar: 1,451 +/- 287 ng/g for Hg(II) and 1,346 +/- 143 ng/g for MeHg. In the crustaceans, Hg bioaccumulation was analyzed at the whole-organism level and in eight organs (gills, stomach, intestine, hepatopancreas, tail muscle, green gland, carapace, and hemolymph), after 15 and 30 d of exposure. Analysis of the results showed marked differences between Hg(II) and MeHg accumulation in favor of MeHg: for the direct route, the ratio between metal concentrations was close to 8; for the trophic route, no significant increase in Hg accumulation was observed for Hg(II) even when the ratio between Hg concentration in the direct plus trophic contamination route and Hg concentration in the direct contamination route was 1.6 for MeHg, with an estimated trophic transfer rate close to 20%. Mercury organotropism was also specifically connected to the exposure conditions, especially at the biological barrier level according to the route of exposure: gills and carapace for the direct route and digestive tract including hepatopancreas for the trophic route.

The accumulation and retention of 95mTc by the Norway lobster, Nephrops norvegicus L.

Laboratory experiments were carried out to study bioaccumulation and determine a concentration factor (CF) for technetium ( 95mTc) in the homarid crustacean Nephrops norvegicus L. The steady state CF for accumulation from seawater was estimated to be about 2000 and the biological half-time was about 50 days. The highest tissue Tc concentrations were found in the green gland and the digestive gland. Depuration following accumulation from water was slow with a half-time of about 165 days. Tc accumulation from labelled food followed a biphasic model with one compartment containing about 94 percent of the ingested activity and with a half-time of about 1 day and the second compartment containing about 6 percent of the ingested activity with a half-time of about 56 days. Most retained activity was found in the digestive gland.

Comparative experimental study of cadmium and methylmercury trophic transfers between the asiatic clam Corbicula fluminea and the crayfish Astacus astacus.

Cadmium (Cd) and methylmercury (MeHg) trophic transfers were analyzed between the Asiatic clam Corbicula fluminea and the crayfish Astacus astacus. Metal bioaccumulation in crayfish was quantified after 5, 10, and 15 days of exposure via daily ingestion of soft bodies of C. fluminea, previously exposed during 7 days to Cd (20 microg. L(-1)) and MeHg (4 microg. L(-1)). Bioaccumulation kinetics in the predator were investigated at organ and tissue levels: hemolymph, tail muscle, hepatopancreas, gills, stomach/mesenteron, intestine, green gland, carapace. Trophic transfer rates were estimated at the whole organism level. Results showed marked differences (1) in assimilation efficiencies, mean transfer rates being 5% for Cd and 16% for MeHg; and (2) in the metal distribution within the different tissue compartments of the crayfish: for Cd, the trophic uptake leads to high concentrations in the hepatopancreas and small accumulation in the muscle tissue; for MeHg, the highest levels of bioaccumulation occur in the green gland and in the tail muscle. From an ecotoxicological point of view, these experimental data suggest a small risk of Cd transfer between the crayfish and predators, humans included; on the other hand, Hg distribution in the muscle and accumulation trends in this tissue represent an obvious risk of transfer.

Is technetium‐99 (Tc‐99) radiologically significant?*

According to radiological protection authorities the radioisotope technetium‐99 (Tc‐99) is not ‘radiologically significant’ to humans or other species. The Sellafield plutonium reprocessing plant discharges large amounts of Tc‐99 into the Irish Sea; by the year 2015 a total of about 3,000 tera‐becquerels of Tc‐99, weighing about 5 tonnes, will have been discharged. This article considers the effects of Tc‐99 on the environment. After discharge, Tc‐99 travels large distances in the ocean. Levels of Tc‐99 in Norwegian coastal waters increased by ten times between 1991 and 1996. Tc‐99 becomes concentrated offshore in seaweed, winkles and mussels. A concentration factor of 120,000 has been reported in seaweed and one of 650,000 has been measured in the green gland of lobster. It may be necessary to reassess the risk to human health following the ingestion of the relevant isotopes, including Tc‐99, because of the possibility of radiation induced genomic instability, as well as the cancer risk. The committed effective doses used to determine permitted levels of intake of these isotopes should be increased and the authorized limits for the discharge of radioactive wastes from Sellafield reduced. Authorized limits of the discharge of radioactivity should be based on Contaminated Food Intervention Levels rather than Generalized Derived Limits as they are now.

Benzo[a]pyrene Metabolism by the Hepatopancreas and Green Gland of the Red Swamp Crayfish, Procambarus clarkii, In Vitro

The aim of this study was to determine the potential of activating the pro-carcinogen benzo[a]pyrene (B[a]P), elucidating B[a]P metabolite profiles, and to determine pyridine nucleotide-independent peroxygenase activity of Procambarus clarkii hepatopancreas and green gland microsomal cytochromes P450 in vitro. We compare these data to metabolite profiles generated with the rat ( Rattus norvegicus) system. The major NAD(P)H-dependent metabolite formed by both hepatopancreas and green gland microsomal fractions was 3-OH-B[a]P; cumene hydroperoxide-dependent metabolism of B[a]P produced primarily B[a]P-quinones. B[a]P hydroxylase activity is limited by low microsomal NAD(P)H-dependent cytochrome P450 reductase levels and activity.