Age and growth of the fan mussel Pinna nobilis from south-east Spanish Mediterranean seagrass (Posidonia oceanica) meadows

The calcitic and aragonitic shell of the fan mussel Pinna nobilis L. contains a record of the environmental changes experienced during its growth. Stable-isotope analyses of oxygen (¹⁸O:¹⁶O) in shell carbonate from the calcitic outer shell-layer have been used to validate the periodicity of clearly defined concentric rings on the aragonitic posterior adductor-muscle scar and to estimate the age and growth of fan mussels growing in Posidonia oceanica (L.) meadows at four locations on the south-east Spanish Mediterranean coast. The stable oxygen-isotope records obtained at intervals along a profile across the shell surface enabled seasonal changes in water temperature to be established, and hence seasonal patterns of shell growth to be inferred. Muscle-scar rings were found to be deposited annually in the shell in the spring and early summer (a period of increasing water temperatures), and represent an interruption in the migration of the posterior adductor muscle along the inner surface of the shell. In small pinnids (<25 cm) accretion of the shell is rapid during the first year, but in the second year it is distinctly slower than at the same time the previous year. This slowing down in growth during the second year coincides with the appearance of the “first” distinct muscle-scar ring, indicating that Pinna nobilis does not form a muscle-scar ring during its first year of shell growth. Maximum growth rates were recorded amongst pinnids from Carboneras, where they achieved a length of 59 cm in 8 yr, whilst those from Aguamarga were estimated to be the oldest (attaining a length of 45 cm in 13 yr). Received: 26 January 1998 / Accepted: 8 October 1998     

Oxygen and carbon stable isotopic profiles of the fan mussel, Pinna nobilis, and reconstruction of sea surface temperatures in the Mediterranean

Stable oxygen and carbon isotope profiles ('¹⁸O_skeletal and '¹³C_skeletal), taken along the direction of growth from the umbo to the shell margin in shells of the pinnid Pinna nobilis, were used to reconstruct sea surface temperatures (SST) in the south-east Mediterranean and ontogenetic records of metabolic CO₂ incorporation. Comparison of the seasonal cycle of SST, predicted from the '¹⁸O_skeletal record of a small (young) rapidly growing pinnid and temperature measured with a continuous in situ recorder showed that P. nobilis calcifies under isotopic equilibrium with surrounding seawater, thus indicating that P. nobilis shells can be used as a reliable predictor of SST. A 10-year SST record for the south-east Mediterranean was reconstructed from the shell profiles of four pinnid shells of different sizes and ages collected in 1995 and 1996. Reliable resolution of the seasonal SST could only be achieved during the first 4 years of shell growth. As the pinnids grew older, the temperature record was poorly resolved because the shell growth had diminished with age, resulting in time-averaging of the record. The amplitude of the generated seasonal temperature cycle compared favourably (DŽ°C) with a long-term temperature record from northern Mediterranean waters. Clear seasonal cycles in '¹³C_skeletal were observed with an amplitude of ~1.0‰, similar to the calculated seasonal changes in '¹³C of seawater (0.6‰) overlying seagrass meadows. An ontogenetic trend towards less positive '¹³C_skeletal values was too large to be attributed to any decrease in '¹³C in seawater resulting from the invasion of anthropogenic CO₂. It is suggested that the temporal changes of '¹³C_skeletal are due to incorporation of respiratory CO₂ into the extrapallial fluid and reflect changes in the metabolic activity of the pinnid rather than changes in the isotopic composition of dissolved inorganic carbon within the surrounding seawater.     

Lipid composition of eggs and adductor muscle in giant scallops (Placopecten magellanicus) from different habitats

Scallops (Placopecten magellanicus Gmelin) were collected during August 1989 from shallow water (10 m) and deep water (31 m) habitats at Sunnyside, Trinity Bay, Newfoundland, to compare the lipid composition of eggs and adductor muscle tissue. Less favorable food levels and lower temperature conditions associated with deeper water have previously been shown to produce slower growth and reduced fecundity in individuals from this habitat. Triacylglycerol reserves consistently accounted for 60% of the total lipids present in both groups. The total lipid content of the eggs and the composition of their triacylglycerol fatty acid pools were similar in shallow water and deep water scallops, indicating very little if any nutritional difference between the two groups. Relative to their counterparts from shallow water, individuals from deeper water contained higher proportions of docosahexaenoic acid [22:6(n-3)] in the egg phospholipids and higher levels of 24-methylenecholesterol (a phytosterol commonly found in diatoms) in the adductor muscle. Differences in fatty acid composition are interpreted as biochemical adjustments of cell membranes to increase membrane fluidity, thereby compensating for the lower temperatures prevailing at the greater depth.     

Changes in the digestive gland of Euphausia superba during short-term starvation: lipid class,fatty acid and sterol content and composition

During a period of short-term (19 d) starvation, total lipid in the digestive gland of Euphausia superba Dana decreased from 21 to 9% dry weight. Total lipid per digestive gland decreased significantly during starvation compared to Day 0 individuals, falling from 1960 (±172) to 385 (±81) g. Polar lipid was the major lipid class utilised during starvation, falling from 1510 (±225) to 177 (±46) g per digestive gland (76 to 45%). Absolute levels of triacylglycerol fell from 300 (±41) to 76 (±5) g; however, relative levels remained unchanged. The relative level of free fatty acid increased significantly with starvation (4 to 39%) with absolute levels ranging from 79 (±1) to 156 (±20) g per digestive gland. Absolute levels of all fatty acids per digestive gland declined continually until the end of the starvation period. The long-chain polyunsaturated acids eicosapentaenoic (20:53) and docosahexaenoic (22:63), decreased with starvation from 37 to 26% and 15 to 10%, respectively whereas the saturated fatty acid, palmitic acid (16:0), increased from 15 to 20%. Cholesterol, the major sterol in this organ, increased from 17 (±20) to 44 (±13) g per digestive gland by Day 3, and by Day 19 had returned to levels found in the digestive gland of Day 0 individuals. Desmosterol followed a similar pattern to cholesterol, increasing from 3 (±1) g per digestive gland on Day 0 to 11 (±4) g on Day 3, and falling to 2 (±1) g on Day 19. Other sterols in the digestive gland, predominantly of algal origin, fell from the levels found in Day 0 individuals to near zero amounts by Day 6. The digestive gland of E. superba plays a dynamic role during shortterm starvation in terms of lipid content and composition. The relative levels of polar lipids, free fatty acids and cholesterol in the digestive gland may provide reliable indices of the nutritional condition of E. superba in the field. Sterols in the digestive gland are indicative of recent dietary composition of krill, and may also be used to quantify dietary input from individual phytoplanktonic species.     

Lipids in the digestive gland and the gonad of immature and mature Sepia officinalis (Mollusca: Cephalopoda)

The lipid content of the digestive gland and the gonad of cuttlefishes (Sepia officinalis L.) caught off the French coasts in 1979–1980 was determined and analysed by thinlayer chromatography. The total sterol and phospholipid levels were also determined. The results from immature and mature females and males were compared in an attempt to correlate variations of the lipids with sex or state of gonad maturation. The fluctuations in the lipid level of the digestive gland, which acts as a storage organ, seemed far better related to the diet than to sex or sexual maturity. In the gonads, the lipids were few and seemed to be mostly membrane constituents. However, the increase of phospholipids in the mature ovary could be related to yolk synthesis.     

Lipid class and fatty acid composition of brain lipids from Atlantic herring (Clupea harengus) at different stages of development

Little is known about the changes in composition of brain lipids and fatty acids at different stages of development in fish. Wild Atlantic herring (Clupea harengus L.) were collected from Loch Linnhe and the Firth of Clyde, Scotland, from August 1990 to March 1991. Lipid class and fatty acid compositions of brain lipids were studied at four different stages of development: larvae at the end of the yolk sac stage, two juvenile stages and sexually mature adults. The total lipid content in brains increased during development, and larval brains contained higher proportions of neutral lipids and lower proportions of polar lipids than the brains of juvenile or adult herring. Increased proportions of polar lipids in juvenile and adult herring brains were mainly due to increased percentages of phosphatidylcholine (PC), phosphatidylethanolamine (PE), cerebrosides and sulphatides. The increase in the proportions of the glycolipid classes suggested increasing levels of myelination with development. In total lipids, saturated fatty acids generally decreased and monounsaturated fatty acids and dimethyl acetals (derived from PE-plasmalogen) increased from larvae to adults. However, the proportions of polyunsaturated fatty acids in individual phosphoglycerides were generally highest in juvenile stages, due mainly to increased 22:6n-3, and were lowest in adult fish. Relatively high percentages of 24:1 isomers were found in all the phosphoglycerides, but primarily PC, and these increased during development from larvae to adult. Fatty acids were distributed between individual phosphoglycerides with a characteristic pattern that did not change with development, although the relative amounts of individual fatty acids were altered. The variations and roles of the different lipid components of herring brain are discussed with respect to lipid compositions and functions in brains of other fishes and vertebrates.     

Adenylate cyclase of Mytilus galloprovincialis posterior adductor muscle: basal properties and sensitivity to serotonin

The presence and characteristics of a membrane-bound adenylate cyclase from Mytilus galloprovincialis Lmk posterior adductor muscle have been investigated. The enzyme has a Michaelis constant (K _m) of 0.38 mM at 20°C and requires divalent cations (Mg²⁺/Mn²⁺) for its activity. Optimal GTP concentrations are between 10^-5 and 10^-4 M. The non-hydrolizable GTP-analogues GMPpNHp and GTPS increase the activity of the enzyme four- to ten-fold. Sodium fluoride stimulates the enzymatic activity seven- to eight-fold. Forskolin increases the enzymatic activity two- to three-fold. Serotonin stimulates the adenylate cyclase activity in a dose-dependent manner. These experiments were performed with mussels collected from the estuary of Muros, Spain, in 1990.     

Mitochondrial plasticity in brachiopod (Liothyrella spp.) smooth adductor muscle as a result of season and latitude

Habitat temperature and mitochondrial volume density (Vv_(mt,mf)) are negatively correlated in fishes, while seasonal acclimatization may increase Vv_(mt,mf) or the surface density of the mitochondrial cristae (Sv_(im,mt)). The effect of temperature on invertebrate mitochondria is essentially unknown. A comparison of two articulate brachiopod species, Liothyrella uva collected from Rothera Station, Antarctica in summer 2007, and Liothyrella neozelanica collected from Fiordland, New Zealand in winter 2007 and summer 2008, revealed a higher Vv_(mt,mf) in the Antarctic brachiopod. The Sv_(im,mt) was, however, significantly lower, indicating the Antarctic brachiopods have more, less reactive mitochondria. L. uva, from the colder environment, had larger adductor muscles in both absolute and relative terms than the temperate L. neozelanica. Furthermore, a seasonal comparison (winter vs. summer) in L. neozelanica showed that the absolute and relative size of the adductor increased in winter, Vv_(mt,mf) was unchanged, and Sv_(im,mt) was significantly increased. Thus, seasonal acclimatization to the cold resulted in the same number of more reactive mitochondria. L. neozelanica was clearly able to adapt to seasonal changes using a different mechanism, i.e. primarily through regulation of cristae surface area as opposed to mitochondrial volume density. Furthermore, given the evolutionary age of these living fossils (i.e. approximately 550 million years), this suggests that mitochondrial plasticity has roots extending far back into evolutionary history.     

Protein and amino acid composition of the tergal gland secretions ofBlatta orientalis andEurycotis floridana (Dictyoptera: Blattidae)

Summary Nymphs and adult females ofBlatta orientalis and nymphs ofEurycotis floridana produce a proteinaceous sticky secretion which accumulates on the last abdominal tergites. The proteic patterns do not differ between individuals of the same species. HPLC analyses show that all the common amino acids are found in both species, aspartic and glutamic acids representing 24 to 37% of the total amount of amino acids. InB. orientalis, glutamic acid is the more abundant amino acid whereas inE. floridana it is the aspartic acid. The secretion appears and accumulates rapidly on isolated insects. Behavioural assays revealed that these secretions have a defensive role.     

Adsorption and partition of benzo(a)pyrene on sediments with different particle sizes from the Yellow River

Experiments have been carried out to study the sorption of Benzo(a)pyrene(Bap) on sediment particles from the Yellow River using a batch equilibration technique. Effects of particle size on the adsorption and partition of Bap were investigated with the particle content of 3 g/L. Several significant results were obtained from the study. (1) Isotherms of Bap could be fitted with the dual adsorption-partition model under different particle sizes, and the measured value of the adsorption and partition was in agreement with the theoretical value of the dual adsorption-partition model. (2) When the particle diameter was d ? 0.025 mm, the adsorption was predominant in the sorption of Bap, which accounted for 68.7%–82.4% of the sorption. For the particles with the size of 0.007 mm?d<0.025 mm, the adsorption was predominant when the equilibrium concentration of Bap was 0–8.87 μg/L in the water phase; and the partition was predominant when the equilibrium concentration of Bap was higher than 8.87 μg/L in the water phase. When the particle diameter was d<0.007 mm, the partition was predominant. (3) On the point of particle size, the contribution of adsorption to sorption followed the order: “d?0.025 mm”>“0.007 mm ?d<0.025 mm” >“d<0.007 mm”. (4) The partition coefficients of Bap in solids with different particle sizes were linearly correlated with the organic content, and the K _oc of Bap was about 1.26 × 10⁵ (L/kg).     

Changes in lipid class and fatty acid contents in the ovary and midgut gland of the female fiddler crab Uca tangeri (Decapoda,Ocypodiadae) during maturation

Changes in biochemical composition, lipid class and fatty acid contents were studied in the ovaries and midgut glands of the fiddler crabs Uca tangeri Eydoux during maturation. Wild females were caught during spring and early summer of 1992 in the Bay of Cádiz (southwest Spain), near the mouth of the San Pedro river. Protein and total lipid contents in the ovaries increased significantly from Stages III to IV, at the expense of total carbohydrate, which showed a large decrease during the same period. In the midgut gland, the protein content did not present any significant variation, whereas total lipids and total carbohydrates presented opposite up and down trends during maturation. In the ovary, total polar lipids increased significantly during the final phase of maturation (Stages III to IV), mainly due to the significant contribution of the phosphatidylcholine and phosphatidylethanolamine fractions. In contrast, total neutral lipids showed an upward trend throughout the whole maturation period, mainly due to significant increases of the triacylglycerol fraction. In the midgut gland, total polar lipids (mainly phosphatidylcholine) and total neutral lipids (mainly triacylglycerol) presented significant decreases from Stages II to III, the phase which preceded major increases in both polar and neutral lipids in the ovaries. Cholesterol content did not vary during maturation in either organ, in the ovary or midgut gland. Major fatty acids in the ovaries [16:0, 16:1 (n-7), 18:1 (n-9), 18:1 (n-7), 18:2 (n-6), 18:3 (n-3), 20:4 (n-6), 20:5 (n-3) and 22:6 (n-3)] did, however, accumulate significantly at later stages of maturation. It is noteworthy that arachidonic acid [20:4 (n-6)] content remained constant during all stages of maturation but decreased significantly in total polar lipids in the later phases of maturation. In contrast, eicosapentaenoic acid [20:5 (n-3)] increased significantly in all lipid fractions in the later stages, and docosahexaenoic acid [22:6 (n-3)] remained constant in the polar lipids and increased during later stages in the triacylglycerol fraction. Major fatty acids in the midgut gland lipids showed significant decreases from Stages II to III, just before the final period of maturation.     

Essential fatty acid (docosahexaenoic acid, DHA) availability affects growth of larval herring in the field

Larval fish growth and survival depends not only on prey quantity, but also on prey quality. To investigate effects of prey fatty acid concentration on larval herring growth, we collected different prey organisms and larval herring (Clupea harengus L.) in the Kiel Canal during the spring season of 2009. Along with biotic background data, we analysed fatty acids both in prey organisms and in the larvae and used biochemically derived growth rates of the larvae as the response variable. Larval herring reached their highest RNA/DNA derived growth rates only at high docosahexaenoic acid (DHA) concentration. When the ratio of copepodids to lesser quality cirriped nauplii was low, larval growth and larval DHA concentration were both significantly negatively affected. This was true even as prey abundance was increasing. This finding indicates that even in mixed, natural feeding conditions, growth variations are associated with DHA availability in larval fish.     

R-cells and the digestive cycle in Penaeus semisulcatus (Crustacea: Decapoda)

Shrimp, Penaeus semisulcatus, were collected from Kuwaiti waters in 1980, and the R-cells in the hepatopancreas were observed during the digestive cycle. During the first 12 h they absorb soluble material from the lumen of the gland and, subsequently, they take-up soluble and particulate material from the haemolymph. Within the cytoplasm, apical and basal systems of smooth endoplasmic reticulum are concerned with these processes. Pinocytosis only occurs at the basal cell membrane. The absorbed material is stored as lipid and glycogen, and copper, sulphur and other elements are accumulated in a large dense vacuole. These activities are integrated with those of the other cell types to effect the assimilation of food in the hepatopancreas. A scheme is proposed which accounts for the main processes of digestion. The hepatopancreas governs the duration of the digestive cycle, which takes at least 24 h. Observations on the nature of intracellular storage and waste products could be used to assess the dietary requirements of artificially reared shrimp.     

Growth and mortality rates of the fan mussel <Emphasis Type="Italic">Pinna nobilis</Emphasis> in Lake Vouliagmeni (Korinthiakos Gulf,Greece): a generalized additive modelling approach

The temporal patterns and the effect of shell size and depth on growth and mortality rates of the endangered fan mussel Pinna nobilis were investigated in the marine Lake Vouliagmeni (Korinthiakos Gulf, Greece). A total of 160 individuals were tagged and monitored monthly for a period of 17 months. At each visit, the size of the tagged individuals (shell width, w) was measured in situ and recorded. Any mortality event was also recorded and attributed to natural causes or (illegal) fishing. Growth and mortality rates were modeled with generalized additive models, which are non-parametric flexible models that free the researcher from the limiting concept of a strict parametric shape. The use of GAMs allowed the exploration of shapes of growth and mortality response curves in relation to predictor variables and allowed the fitting of statistical models that better agree with ecological theory. Growth rates had a seasonal pattern, with an extended period of very slow growth between late autumn and early spring, i.e., during the cold season, another short period of slow growth during August (when water temperatures reached their maximum values exceeding 29°C), and a peak in growth rates during late spring–early summer, probably related to an optimum combination of temperature and food availability. Growth rates varied with shell size, with a peak at w ∼4.5 cm, followed by a sharp decline to an approximately constant level, with sizes ranging from 9 to 15 cm, and a further decline with larger sizes down to almost zero for w > 20 cm. Growth rates did not vary substantially with depth. Although P. nobilis is a protected species in the EU and its fishing is strictly prohibited, fishing mortality was very high in Lake Vouliagmeni (much greater than natural mortality), especially during the hot season when the lake was crowded by summer visitors. The fan mussels were poached exclusively by free-diving and due to the high turbidity of the lake’s water, fishing mortality was higher in shallow areas (and mostly for large individuals) and was practically zero at depths >9 m. Due to fishing mortality, a size segregation of P. nobilis was observed in the lake: large individuals were restricted to deeper areas, while young and small individuals were more abundant in shallow areas where there was preferential recruitment. Natural mortality was strikingly size dependent and P. nobilis suffered high natural mortality during the first year of life; the probability of death by natural causes quickly diminished as the fan mussels grew in size. No depth-related differences in natural mortality were found.     

Embryogenesis of decapod crustaceans with different life history traits,feeding ecologies and habitats: a fatty acid approach

Variations in embryo size and fatty acid (FA) dynamics during embryogenesis were evaluated in deep-sea pandalids and portunid swimming crabs from the Portuguese continental margin and Madeira Island slope and compared with previous data on neritic and deep-sea lobsters and shrimps (collected between February 2001 and March 2004). Inter-specific variations in embryo size seem to be dictated primarily by phylogeny rather than by differences in reproductive or early life history traits. FA reserves were significantly correlated with embryo size (P < 0.001). Principal component analysis revealed differences among three groups (1—neritic caridean shrimps, 2—deep-sea pandalids of the genus Plesionika, and lobsters, 3—portunid crabs and the deep-sea pandalid Chlorotocus crassicornis, Costa 1871). Group 1 was clearly separated by PC1 mainly due to the higher percentage of essential C₁₈ (linoleic and linolenic acids) and C₂₀ (namely eicosapentaenoic) polyunsaturated FA (specific markers of primary producers). PC2 separated Group 2 from Group 3 due to differences in the percentage of several saturated FA (including odd-numbered FA—bacterial markers) and C₁₈ monounsaturated FA (namely 18:1n − 9, a general marker of carnivory). Therefore, these differences among groups seem to result from distinctions in diet and ecological niche. Intra-specific differences in FA composition between western and southern Plesionika martia martia (A. Milne-Edwards, 1883) populations may reflect higher water temperatures on the south sub-tropical coast. Lobster embryonic development was more demanding of lipid energy than that of the other decapod species, which may reflect an evolutionary trend in decapod taxa related to an increasing degree of lecithotrophy. However, a lower FA catabolism can be interpreted as an enhanced independence of the newly hatched larvae from external energy sources. Higher FA content at hatching and, as a consequence, a greater independence from the external environment should increase the chances of larval survival. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Allozyme electrophoresis indicates high gene flow between populations of Holothuria (Microthele) nobilis (Holothuroidea: Aspidochirotida) on the Great Barrier Reef

 Genetic variation in 15 Holothuria (Microthele) nobilis (Selenka, 1867) populations on the Great Barrier Reef was studied at seven polymorphic allozyme loci. Although populations were separated by distances up to 1300 km, there were no apparent restrictions to gene flow (F _ST values were not significantly different from 0) and the maximum Nei's unbiased genetic distance was 0.003. Populations were in Hardy–Weinberg equilibrium at all loci. The estimated maximum sexual input [this is the ratio of the number of sexually produced individuals (N*) to the sample size (N _i )] and the minimum sexual input [this is the ratio of the number of genotypes (N _go ) over the sample size (N _i )] were used as estimators for the amount of asexual reproduction. Both parameters suggested that H. nobilis reproduces solely by sexual means (N*:N _i : = 1; N _go :N _i  = 0.74 to 1). The allozyme data indicated high gene flow between populations, but the possibility that allozyme frequencies may not be at equilibrium means that it was not possible to distinguish whether the patterns reflect present-day dispersal or dispersal that occurred in the past. Received: 27 March 2000 / Accepted: 29 June 2000     

Use of the digestive gland of the oyster Crassostrea rhizophorae (Guilding, 1828) as a bioindicator of Zn,Cd and Cu contamination in estuarine sediments (south-east Brazil)

This study demonstrates the accumulation of Zn, Cd and Cu in the digestive gland of the oyster Crassostrea rhizophorae in response to the contamination of sediments and discusses the potential use of this specific organ in monitoring metal contamination in tropical areas. Sediment and oyster samples were collected from coastal Rio de Janeiro sites with different levels of human impact: Sepetiba Bay, Guanabara Bay and the Paraty coast. Metal concentrations were measured using inductively coupled plasma optical emission spectrometry (ICP OES). Significant statistical differences (p<0.001; p<0.05) were observed for Zn and Cd concentrations in the digestive gland; the highest Zn concentrations were found at Sepetiba, followed by Guanabara and Paraty. The highest digestive gland Cd concentrations were found at Paraty, followed by Sepetiba and Guanabara. These concentrations were proportional to those found in the sediments. There was no significant difference (p>0.05) in Cu among the sampling sites. The highest digestive-gland Cu concentration was also found at Sepetiba, followed by Guanabara. The biosediment accumulation factor indicated a gradient of sediment contamination for Zn and Cd. The digestive gland of C. rhizophorae can be a potential indicator of trace metal contamination in sediments from tropical estuarine environments.     

Structural and functional peculiarities of the digestive system of Cucumaria frondosa (Echinodermata: Holothuroidea)

The fine structure of the intestinal epithelium of Cucumaria frondosa has been examined. The digestive cells possessed some specific ultrastructural peculiarities which testify to their participation in the transport of substances and in the processes of intracellular and cavitary digestion. The main units of the intestinal epithelium appear to be multifunctional digestive cells in which the phenomenon of compartmentalization among the organelles' groups, intended to carry out various functions, occurs. The heterogeneity of the structure of populations of the digestive cells is explained. Both primitive and progressive features of the structure of the digestive tract of C. frondosa are indicated.     

Gene expression profiling of human liver carcinoma (HepG2) cells exposed to the marine toxin okadaic acid

The marine toxin, okadaic acid (OA) is produced by dinoflagellates of the genera Prorocentrum and Dinophysis and is the causative agent of the syndrome known as diarrheic shellfish poisoning. In addition, OA acts as both a tumor promoter, attributed to OA-induced inhibition of protein phosphatases as well as an inducer of apoptosis. To better understand the potentially divergent toxicological profile of OA, the concentration-dependent cytotoxicity and alterations in gene expression on the human liver tumor cell line HepG2 upon OA exposure were determined using RNA microarrays, DNA fragmentation, and cell proliferation assays as well as determinations of cell detachment and cell death in different concentrations of OA. mRNA expression was quantified for approximately 15,000 genes. Cell attachment and proliferation were both negatively correlated with OA concentration. Detached cells displayed necrotic DNA signatures but apoptosis also was broadly observed. Data suggest that OA has a concentration dependent effect on cell cycle, which might explain the divergent effects that at low concentration OA stimulates genes involved in the cell cycle and at high concentrations it stimulates apoptosis.     

全氟辛酸和全氟辛基磺酸的光降解技术及机理研究进展

目前,普遍存在于各种环境介质中的全氟辛酸(PFOA)和全氟辛基磺酸(PFOS)造成的环境污染问题已引起全球的广泛关注.PFOA和PFOS具有稳定性、持久性和生物累积性等特点.常规的方法如:超声降解法、电化学氧化法和微生物降解法等,很难将其彻底降解,因此开发有效的PFOA和PFOS降解技术成为了环境领域的研究重点.近年来...