The vitamin content of microalgae used in aquaculture

The vitamin content in four Australian microalgae, a Nannochloropsis-like sp., Pavlova pinguis, Stichococcus sp. and Tetraselmis sp., were examined. These were grown under a 12:12 h light:dark regimen (100 μmol photon m⁻²s⁻¹) and harvested during late-logarithmic phase. Typically, the content showed a two- to three fold range between the species. When expressed on a dry weight basis, the content of ascorbate ranged from 1.3 to 3.0 mg g⁻¹, β-carotene from 0.37 to 1.05 mg g⁻¹, α-tocopherol from 0.07 to 0.29 mg g⁻¹, thiamine from 29 to 109 μg g⁻¹, riboflavin from 25 to 50 μg g⁻¹, total folates from 17 to 24 μg g⁻¹, pyridoxine from 3.6 to 17 μg g⁻¹, cobalamin from 1.70 to 1.95 μg g⁻¹ and biotin from 1.1 to 1.9 μg g⁻¹. Retinol was detected only in Tetraselmis sp. (2.2 μg g⁻¹); any vitamins D₂ or D₃ were below the detection limit (≤0.45 μg g⁻¹). Nannochloropsis sp. was also grown under a 24:0 h light:dark light cycle and harvested at stationary phase. The content of most vitamins in Nannochloropsis sp. cultures differed significantly, and the degree of variation was similar to that observed between the four species grown under 12:12 h light:dark regimen (100 μmol photon m⁻²s⁻¹) and harvested during late-logarithmic phase. Thiamine content was also examined in six non-Australian strains commonly used in aquaculture, Chaetoceros muelleri, Thalassiosira pseudonana, Nannochloris atomus, Nannochloropsis oculata, Isochrysis sp. (T.ISO) and Pavlova lutheri. Values (average 61 μg g⁻¹; range 40 to 82) were similar to those in the Australian strains (average 61 μg g⁻¹; range 29 to 109) and increased during stationary phase (average 94 μg g⁻¹; 38 to 131). Comparison of the data with the known nutritional requirements for marine fish species and prawns suggests that the microalgae should provide excess or adequate levels of the vitamins for aquaculture food chains. The data may be used to guide the content of vitamins included in micro-diets developed as replacements for live diets. This revised version was published online in July 2006 with corrections to the Cover Date.     

The ascorbic acid content of eleven species of microalgae used in mariculture

The ascorbic acid (vitamin C) concentrations in 11 species of microalgae commonly used in mariculture were determined. The species examined were 4 diatoms (Chaetoceros calcitrans (Paulsen) Takano,Chaetoceros gracilis Schütt,Skeletonema costatum (Greville) Cleve,Thalassiosira pseudonana (Hustedt, clone 3H) Hasle and Heimdal); 2 prymnesiophytes (Isochrysis sp. (clone T.ISO) Parke,Pavlova lutheri (Droop) Green); 1 prasinophyte (Tetraselmis suecica (Kylin) Butcher); 2 chlorophytes (Dunaliella tertiolecta Butcher,Nannochloris atomus Butcher); 1 eustigmatophyte (Nannochloropsis oculata (Droop) Green); and 1 cryptophyte (Chroomonas salina (Wislouch) Butcher). Duplicate cultures of each species were grown under defined conditions and analysed during both logarithmic and stationary phase of growth.Average values for ascorbic acid ranged from 9.4 fg cell^–1 (N. oculata, stationary phase) to 700 fg cell^–1 (S. costatum, stationary phase). This value was generally related to cell size. Levels of ascorbic acid cell^–1 increased during the stationary growth phase forS. costatum andD. tertiolecta and decreased forC. gracilis, T. pseudonana, C. salina andN. oculata. Levels did not change significantly for the remaining species.Average values for per cent ascorbic acid ranged from 0.11% (T. pseudonana, stationary phase) to 1.62% of dry weight (C. gracilis, logarithmic phase). The per cent ascorbic acid was not related to algal class. Also, the percentage between logarithmic and stationary phase cultures differed for many of the species, but differences were unrelated to algal class.Chaetoceros gracilis, T. pseudonana, N. oculata andIsochrysis sp. (T.ISO) had higher per cent ascorbic acid during the logarithmic phase, whereasD. tertiolecta andN. atomus contained more per cent ascorbic acid during the stationary phase.Despite the differences in the composition of the different microalgae (0.11–1.62% ascorbic acid), all species would provide a rich source of ascorbic acid for maricultured animals, which can require 0.003–0.02% of the vitamin in their diet.     

Effects of diurnal fluctuations in light intensity on the efficiency of growth of Skeletonema costatum (Grev.) Cleve (Bacillariophyceae) in a cyclostat

The effects of diurnal variations in light intensity on the biomass characteristics and the efficiency of daily growth of Skeletonema costatum (Grev.) Cleve were evaluated. The relative importance of changes in carbon specific rates of respiration and organic release to the efficiency of growth was determined. Light intensity was either constant at 130 μE · m^?2 · s^?1 during the light period or fluctuated throughout the light period from 500 to 10 μE · m^?2 · s^?1 at rates of either 1 or 12 cycles · day^?1. Total daily light was equivalent for all light regimes at 5.6 E · m^?2 · day^?1.Daily rates of growth remained comparable at ≈ 1 · day^?1 under constant and fluctuating light regimes. Cell size as daily mean carbon · cell^?1, nitrogen · cell^?1 and cellular volume was decreased under diurnally varying light whereas daily mean chlorophyll a · cell^?1 was unaffected.Rates of respiration, organic release and gross production were elevated several fold under diurnally varying light in comparison to constant light. Net growth efficiency decreased from 0.69 under constant light to values of 0.50 and 0.38 under 1 and 12 cycles · day^?1, respectively. Decreased efficiency of growth under diurnally fluctuating light resulted mostly from greater respiratory activity while organic release remained < 10% of gross production. Increased rates of gross production reflected enhancement in the efficiency of carbon fixation with fluctuating light.     

Antifouling potential of the marine microalga Dunaliella salina

Marine organisms have usually been viewed as sources of environmentally friendly compounds with antifouling activity. We performed a series of operations to investigate the antifouling potential of the marine microalga Dunaliella salina. For the ethyl acetate crude extract, the antialgal activity was significant, and the EC₅₀ value against Skeletonema costatum was 58.9 μg ml^?1. The isolated purified extract was tested for antifouling activity, the EC ₅₀ value against S. costatum was 21.2 μg ml^?1, and the LC₅₀ against Balanus amphitrite larvae was 18.8 μg ml^?1. Subsequently, both UHR–TOF–MS and GC–MS were used for the structural elucidation of the compounds, and a series of unsaturated and saturated 16- and 18-carbon fatty acids were detected. The data suggested that the fatty acid extracts from D. salina possess high antifouling activity, and could be used as substitutes for potent, toxic antifouling compounds.     

EFFECTS OF VARIATIONS IN LIGHT INTENSITY ON THE EFFICIENCY OF GROWTH OF SKELETONEMA COSTATUM (BACILLARIOPHYCEAE) IN A CYCLOSTAT1

The relative importance of respiration and organic carbon release to the efficiency of carbon specific growth of Skeletonema costatum (Grev.) Clave was evaluated over a light range from 1500–15 μE · m^?2· s^?1. Net growth efficiency ranged from 0.45–0.69 with a maximum at 130 μE · m^?2· s^?1. Respiration was 93% or more of the variations in growth efficiency. Organic carbon release ranged from 0–7% of gross production and increased with light intensity. Carbon specific particulate production was a hyperbolic function of incident light intensity and was related exponentially to particulate carbon production per unit chlorophyll a. Full sunlight conditions, 1500 μE · m^?2· s^?1, did not induce photoinhibition of gross production. Variations in the efficiency of growth of S. costatum were minimized over a wide range of light intensities mainly because of variations in cellular pigments which permitted the efficient utilization of available light energy, and a reduction in the losses of carbon which increases the growth rate, possibly as a consequence of the recycling of respired carbon within the cell.     

COMPARISONS OF NITRATE UPTAKE, STORAGE, AND REDUCTION IN MARINE DIATOMS AND FLAGELLATES

Diatoms, but not flagellates, have been shown to increase rates of nitrogen release after a shift from a low growth irradiance to a much higher experimental irradiance. We compared NO₃ ^? uptake kinetics, internal inorganic nitrogen storage, and the temperature dependence of the NO₃ ^? reduction enzymes, nitrate (NR) and nitrite reductase (NiR), in nitrogen‐replete cultures of 3 diatoms (Chaetoceros sp., Skeletonema costatum, Thalassiosira weissflogii) and 3 flagellates (Dunaliella tertiolecta, Pavlova lutheri, Prorocentrum minimum) to provide insight into the differences in nitrogen release patterns observed between these species. At NO₃ ^? concentrations <40 μmol‐N·L ^{? 1}, all the diatom species and the dinoflagellate P. minimum exhibited saturating kinetics, whereas the other flagellates, D. tertiolecta and P. lutheri, did not saturate, leading to very high estimated K _s values. Above ～60 μmol‐N·L ^{? 1}, NO₃ ^? uptake rates of all species tested continued to increase in a linear fashion. Rates of NO₃ ^? uptake at 40 μmol‐N·L ^{? 1}, normalized to cellular nitrogen, carbon, cell number, and surface area, were generally greater for diatoms than flagellates. Diatoms stored significant amounts of NO₃ ^? internally, whereas the flagellate species stored significant amounts of NH₄ ⁺ . Half‐saturation concentrations for NR and NiR were similar between all species, but diatoms had significantly lower temperature optima for NR and NiR than did the flagellates tested in most cases. Relative to calculated biosynthetic demands, diatoms were found to have greater NO₃ ^? uptake and NO₃ ^? reduction rates than flagellates. This enhanced capacity for NO₃ ^? uptake and reduction along with the lower optimum temperature for enzyme activity could explain differences in nitrogen release patterns between diatoms and flagellates after an increase in irradiance.     

Isolation of algicidal compounds from the red alga <Emphasis Type="Italic">Corallina pilulifera</Emphasis> against red tide microalgae

We determined the structure of two compounds, namely, 5,8,11,14,17-eicosapentaenoic acid (EPA) and di-n-octylphthalate (DnOP), which have algicidal activity against the toxic dinoflagellate, Cochlodinium polykrikoides. The polyunsaturated fatty acid EPA and the anthropogenic DnOP were isolated from the MeOH extract of the red alga Corallina pilulifera. We also found that a commercial EPA has algicidal activity identical to that of the EPA purified from C. pilulifera. At low inoculum (5.0 × 10² cells mL⁻¹), the highest algicidal activity of a commercial EPA exhibited approximately 92.6% algicidal activity after 1 h and 96.8% after 6 h treatment at 6 μg mL⁻¹, respectively. At high inoculum (1.0 × 10⁴ cells mL⁻¹), the strongest algicidal activity of EPA showed 69.5% after 1 h and 75.5% algicidal activity after 6 h treatment at 6 μg mL⁻¹, respectively. However, EPA did not show algicidal activity against several microalgae used in aquaculture such as Pavlova lutheri, Tetraselmis suecica, Isochrysis galbana, and Nannochloris oculata for 6 h treatment at 6 μg mL⁻¹. The algicidal activity of the five red tide strains to EPA (3 μg mL⁻¹) showed about 86.6%, 86.6%, and 67.3% algicidal activity against Skeletonema costatum, Chaetoceros curvisetus, and C. polykrikoides after 1 h treatment at low inoculum (5.0 × 10² cells mL⁻¹), respectively, but not against Prorocentrum minimum and Scrippsiella trochoidea. We concluded that EPA might be useful as a controlling agent of harmful algal blooms.     

A community of submerged aquatic CAM plants in Lake Kalgaard,Denmark

The CO₂ exchange pattern of leaves of dominant Isoetes lacustris L., Littorella uniflora (L.) Aschers. and Lobelia dortmanna L. from oligotrophic, carbon-poor Lake Kalgaard, Denmark was examined by gas-exchange experiments and by following the diurnal acidity rhythm. Both variables suggest Crassulacean Acid Metabolism (CAM) in Littorella and Isoetes. During the dark, both species had a continuous, but declining CO₂ uptake. The maximum uptake in Littorella was 28 μmol CO₂ g^?1 DW h^?1 or about 36% of the light CO₂ assimilation rate. In Isoetes, corresponding figures were 19 μmol CO₂ g^?1 DW h^?1 and 22%.A peak of 49.5 μEq g^?1 FW titratable acidity (Littorella) and 41.9 μEq g^?1 FW (Isoetes) was found at the end of the dark period, reflecting an increase of 11.6 μEq g^?1 FW (9 h)^?1 (Littorella) and 16.3 μEq g^?1 FW (9 h)^?1 (Isoetes). These results agreed with the cumulative CO₂ assimilation during the dark.The assimilation of CO₂ in the dark is important, apparently, for growth of Littorella and Isoetes in Lake Kalgaard. Lobelia, which exhibits little dark CO₂ assimilation, is also the least abundant species, at less than 1% of the total cover.     

Influence of light and temperature on photosynthesis and respiration by Pithophora oedogonia (Mont.) Wittr. (chlorophyceae)

Rates of net photosynthesis and respiration were determined for Pithophora oedogonia (Mont.) Wittr. acclimatized to 56 combinations of light (7–1200 μE m^?2 s^?1) and temperature (5–35°C). Conditions for maximum net photosynthesis were estimated to be 26°C and 970 μE m^?2 s^?1. The rate of net photosyntheses varied considerably with temperature, with the maximum measured value (9.67 mg O₂ h^?1 g dry wt.^?1) occurring at 25°C. Respiration rate increased with temperature and the light received just prior to measurement. The maximum respiration rate (7.05 mg O₂ g^?1 h^?1) occurred at 30°C and 1200 μE m^?2 s^?1. Exposure of Pithophora to light levels of 600 or 1200 μE m^?2 s^?1 prior to determination of the respiration rate resulted in significantly elevated levels of oxygen consumption at temperatures ≥ 15°C. The relationship between light, temperature and photosynthesis and respiration were summarized as three-dimensional response surfaces.     

Seasonal variation in light- and temperature-dependent growth of marine planktonic diatoms in in situ dialysis cultures in the Trondheimsfjord,norway (63°N)

Three species of diatoms, Skeletonema costatum (Grev.) Cleve, Thalassiosira gravida Cleve, and T. pseudonana (Hustedt) Hasle et Heimdal, were grown in in situ dialysis culture in the Trondheimsfjord at depths of 0.5 and 4 m. The rates of growth and the chemical composition of exponentially growing cells were monitored and related to seasonal changes in illumination and temperature. Functions correlating growth rate with temperature were deduced. Growth took place from February to November. During this period temperature ranged from ?1 to 16°C, the average photon flux density (ifI) (per 24 h) from 9 to 570 μE · m^?2 · s^?1 (0.5 m depth), and the length of the days (I > 1 μE · m^?2 · s^?1) from 6 to 24 h. Light-limited growth was evident when the product of the average daily light and the chlorophyll/N ratio was < 10; this occurred mostly in early spring and late autumn. Peak densities (> 800 for the Thalassiosira spp. and > 1300–1400 μE · m^?2 · s^?1 for Skeletonema) seem to inhibit growth. The highest rates recorded were ≈1.6 doubl. · day^?1 (July, 15–16°C).The three species exhibit different ecological behaviour. Skeletonema is eurythermal (Q₁₀ = 1.8), whereas Thalassiosira pseudonana favours high temperatures, and T. gravida temperatures < 10°C. Moreover, Skeletonema has generally less chlorophyll and more phosphorus and ATP (≈ 1.4 ×) than the other two species. In Skeletonema, the ATP level seems related to the light-governed growth rate, and independent of temperature. In Thalassiosira no such correlation was found.     

Optimization of a Propionibacterium acidipropionici continuous culture utilizing sucrose

To produce propionic acid and vitamin B₁₂ from sucrose, the strain Propionibacterium acidipropionici NRRL B3569 was selected by screening a number of Propionibacterium strains. The nutrient composition and the fermentation conditions for this strain were optimized in continuous culture. The investigations show that within a concentration range of 30–170 g l^–1 of sucrose in the fermentation medium, no significant substrate inhibition occurred. For the production of propionic acid and vitamin B₁₂, concentrations of 1.5 mg FeSO₄·7H₂O g^–1 dry biomass, 0.75 mg cobalt ions g^–1 dry biomass, 0.3 mg 5,6-dimethylbenzimidazole g^–1 dry biomass, and 12 g yeast extract 1^–1 were necessary additions to the sources of nitrogen, phosphate, and magnesium ions. The extra addition of up to 2.8 g betaine g^–1 dry biomass significantly increases the production of vitamin B₁₂. In the optimization of the pH value, temperature, and aeration, it was established that the conditions for propionic acid production and vitamin B₁₂ production are different. Whereas the optimal production of propionic acid took place under completely anaerobic conditions with a pH value of 6.5 and a temperature of 37°C, optimal vitamin B₁₂ production required a temperature of 40°C and aerobic conditions (0.5 vvm aeration at 100 rpm) with a pH value of 6.5.     

Heavy metal tolerance of marine phytoplankton. II. Copper tolerance of three species in dialysis and batch cultures

The tolerance to copper ions of three diatoms, namely, Skeletonema costatum, (Grev.) Cleve, Thalassiosira pseudonana (Hust.) Hasle and Phaeodactylum tricornutum Bohlin grown in dialysis and batch cultures in the local fjord water has been established. Reduction of growth rates was observed by the addition of 10, 25 and 400 μg/1 of copper ions, respectively for the three species investigated. At the higher levels of copper addition (400 and 700 MS/1) cells of P. tricornutum in dialysis culture increased their copper content to more than 200 times over those of the controls, the ratio of copper to chlorophyll in the cells increasing 150 times.All three species showed marked increases in copper content when a copper salt was added to batch cultures of the algae. The two clones of Skeletonema costatum tested showed nearly identical sensitivity to copper ions, but they differed markedly in their zinc tolerance.     

GROWTH OF VITAMIN B12-LIMITED CULTURES: THALASSIOSIRA PSEUDONANA,MONOCHRYSIS LUTHERI,AND ISOCHRYSIS GALBANA1,2

The growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B₁₂ concentrations in the media. In batch cultures, the vitamin B₁₂ half-saturation constants and standard errors were 0.39 ± 0.042 μμg/ml for Thalassiosira pseudonana (clone 3H), 1.69 ± 0.24 μμg/ml for Isochrysis galbana, and 2.77 ± 1.65 μμg/ml for Monochrysis lutheri. A chemostat was used to grow T. pseudonana with vitamin B₁₂ as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 10⁴ cells/μμg vitamin B₁₂, was the same as in the batch culture, 126 ± 13 ± 10⁴ cells/μμg. The chemostat half-saturation constant, 0.26 ± 0.068 μμg/ml vitamin B₁₂, and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B₁₂ concentration on growth rates may be complicated by low concentrations of other nutrients or the presence of inhibitors.     

PRODUCTION OF VITAMIN B12, THIAMINE,AND BIOTIN BY PHYTOPLANKTON1

Some ecologically important phytoplankters released vitamins into culture medium during growth. Skeletonema costatum and Stephanopyxis turris (vitamin B₁₂-requirers) produced both thiamine (vitamin B₁) and biotin when growing with either 12 or 2 ng vitamin B₁₂/liter. Gonyaulax polyedra (vitamin B₁₂-requirer) produced thiamine with 12 ng vitamin B₁₂/liter, and Coccolithus huxleyi (thiamine-requirer) produced vitamin B₁₂ and biotin with 120 ng thiamine/liter, but only biotin with 10 ng thiamine/liter. The amount of vitamin produced by an alga and rate at which it was produced varied with the phytoplankter, the concentration of the required vitamin, and incubation time. Vitamins produced during early and exponential growth were due to excretions, and those produced at stationary growth resulted from excretion and release due to cell lysis. Uptake of the required vitamin by all phytoplankters was greatest during the first few days of incubation. On continued incubation the rate of uptake/cell decreased. In the sea phytoplankters may contribute a major portion of the amount of dissolved vitamins.     

Cultivation of shear stress sensitive and tolerant microalgal species in a tubular photobioreactor equipped with a centrifugal pump

The tolerance to shear stress of Tetraselmis suecica, Isochrysis galbana, Skeletonema costatum, and Chaetoceros muelleri was determined in shear cylinders. The shear tolerance of the microalgae species strongly depends on the strain. I. galbana, S. costatum, and C. muelleri exposed to shear stress between 1.2 and 5.4 Pa resulted in severe cell damage. T. suecica is not sensitive to stresses up to 80 Pa. The possibility to grow these algae in a tubular photobioreactor (PBR) using a centrifugal pump for recirculation of the algae suspension was studied. The shear stresses imposed on the algae in the circulation tubes and at the pressure side of the pump were 0.57 and 1.82 Pa, respectively. The shear stress tolerant T. suecica was successfully cultivated in the PBR. Growth of I. galbana, S. costatum, and C. muelleri in the tubular PBR was not observed, not even at the lowest pumping speed. For the latter shear sensitive strains, the encountered shear stress levels were in the order of magnitude of the determined maximum shear tolerance of the algae. An equation was used to simulate the effect of possible damage of microalgae caused by passages through local high shear zones in centrifugal pumps on the total algae culture in the PBR. This simulation shows that a culture of shear stress sensitive species is bound to collapse after only limited number of passages, confirming the importance of considering shear stress as a process parameter in future design of closed PBRs for microalgal cultivation.     

Reduction in omega-3 fatty acids by UV-B irradiation in microalgae

UV-B irradiation reduced the levels of omega-3 fatty acid, eicosapentaenoic acid (EPA, 20:53) and docosahexaenoic acid (DHA, 22:63), in microalgae; the degree of reduction varied with species.Chaetoceros calcitrans andSkeletonema costatum were high UV-B tolerant species, followed byPhaeodactylum tricornutum, Chroomonas salina, Pavlova lutheri, andThalassiosira pseudonana.Isochrysis galbana (T.ISO) andProrocentrum micans were UV- B sensitive. Cells in logarithmic phase were most sensitive to UV- B irradiation. Nitrate-, phosphate-, or sulphate-starved cells were more UV-B sensitive than non-starved cells grown in a complete basal medium. A relatively short exposure to high UV-B was more damaging than a longer exposure to lower irradiance. Visible light intensity levels had a profound impact on the sensitivity of microalgal cultures to UV-B, with high levels decreasing UV-B dependent damage. Addition of polyamines (putrescine, spermidine or spermine) or an amino acid (cysteine) to the culture medium minimized the reduction of omega-3 fatty acid content in microalgae caused by UV-B irradiation.Author for correspondence     

Growth potential of Lemna gibba: Effect of CO2 enrichment at high photon flux rate

Lemna gibba L. was cultivated in continuous light (800–1200 μmol quanta m^?2s^?1, 320–400 W m^?2) and normal or CO₂-enriched air (1500 μl CO₂ l^?1), with a continuous nutrient supply. Increased CO₂ concentration increased the unit leaf rate (ULR) or net assimilation rate and decreased the leaf area ratio (LAR) (photosynthetic area per unit dry weight), but the relative growth rate was unchanged (0.43 g g^?1 day^?1). The changes in ULR and LAR indicate that organic matter production can be increased with CO₂ enrichment at high photon flux rate (PFR).     

Investigation of Ag in the king scallop Pecten maximus using field and laboratory approaches

The bioaccumulation, tissue and subcellular distributions of Ag were investigated in the king scallop Pecten maximus from the Bay of Seine fishery area (France) in laboratory and in field conditions. Experimental investigations with the radiotracer ^110mAg showed that the scallop readily concentrated Ag when exposed via seawater and to a much lower extent when exposed via sediment. Retention of the metal incorporated via all tested contamination pathways was shown to be very strong, but the assimilation efficiency of Ag ingested with food was found to be tightly depending on the phytoplankton strain used to feed the scallops (74 and 33% with Skeletonema costatum and Isochrysis galbana, respectively). The uptake and depuration kinetic parameters determined in the laboratory experiments were used to run a global bioaccumulation model. The latter indicated that the major uptake pathway of Ag in P. maximus was strongly depending on the food quality. Indeed, when fed the diatom S. costatum which was characterised by a high affinity for Ag (high distribution constant K_df) the relative contribution of the feeding pathway reached 98% of the global Ag bioaccumulation. In contrast, when fed I. galbana which displayed a lower K_df than S. costatum, dietary Ag was retained to a lesser extent by P. maximus, and seawater appeared as the major contributing uptake pathway. In wild scallops collected from reference and contaminated sites, Ag was mainly concentrated in the digestive gland and secondarily in the gills, and was mainly found associated with the insoluble subcellular fraction in all the scallop tissues.     

Production of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in southeastern Brazil

The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, S?o Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/embryos per female × monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25?g AFDW m^?1?year^?1 and the somatic production/biomass ratio (P _s/B) from 3.55 to 3.14?year^?1 for 2004 and 2005, respectively. The P _s/B ratios were higher for males (4.02 and 3.19?year^?1 for 2004 and 2005) than for females (3.10?year^?1 for both years). The annual gonad production (P _g?=?1.07?g AFDW m^?1?year^?1) contributed about 15 and 6% to the total production (P _s?+?P _g) of females and the population, respectively. The proportion of gonad to somatic production of females (P _g/P _s) increased with individual size (ca 90% in the 7.5?mm size class), and the annual weight-specific gonad production (P _g/B ratio) was estimated to 0.24?year^?1. The high P _s/B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P _s/B ratio.     

Antioxidant, anticancer and hepatoprotective activities of Cotoneaster horizontalis Decne extract as well as α-tocopherol and amygdalin production from in vitro culture

The phytochemical analysis of the ethanolic extract of branches of Cotoneaster horizontalis, Decne revealed the presence of: β-carotene, ascorbic acid and less amounts of α-tocopherol and amygdalin (vitamin B₁₇) in proportions of: 2,500, 70, 0.093, 0.334 mg 100 g^?1, respectively. Acute oral toxicity test revealed its safety profile. In vitro study revealed its good 2, 2-diphenyl-1-picrylhydrazyl radical scavenging and anticancer activities. Invivo study, simultaneous administration of this extract at a dose of 100 or 200 mg kg^?1 body weight for 4 weeks, exhibited a significant protection in a dose-dependant manner against hepatotoxicity induced by repeated dose of acetaminophen (1 g kg^?1 body weight day^?1, p.o.) by preserving the liver function parameters, hepatic redox state and serum lipid profile near the healthy levels. Consequently, in vitro culture was carried out on full or half strength of Murashige and Skoog medium supplemented with different concentrations of benzyl amino purine or kinetin provided shootlets production; different concentrations of 2,4-dichlorophenoxy acetic acid and naphthalene acetic acid showed an increase of callus. Determination of α-tocopherol and amygdalin in different shootlets and callus extracts showed a pronounced increases up to 30.62 and 3.69 mg 100 g^?1 in shootlet extract, respectively as well as 26.61 and 12.71 mg 100 g^?1 in callus extract, respectively, as compared with those of the mother plant (0.76 and 0.11 mg 100 g^?1 extract, respectively).