黄海春季浮游植物的调查研究

1998年 5月 16日～ 6月 1日 ,对黄海 ( 33°0 0′～ 39°30′N,12 1°0 0′～ 12 5°30′E)进行了浮游植物调查研究 ,结果显示 :1998年春季黄海已鉴定的浮游植物有 14属 2 9种。其中 ,硅藻门有 10属 2 1种 ,甲藻门 4属 8种。在硅藻门中圆筛藻属的种类最多 ,有 7种 ,其次是根管藻属 ,有 3种。甲藻门中甲藻属的种类最多 ,有 5种。浮游植物的平均数量为 2 .2 3× 10 4 个 / m3,其中 ,硅藻门的平均数量为1.55× 10 4 个 / m3,占浮游植物总量的 69.5% ,甲藻门的平均数量为 0 .68× 10 4 个 / m3,占浮游植物总量的 30 .5%。黄海北部浮游植物的数量高于黄海中、南部。黄海浮游植物分布密集区主要在调查区西、北部。与 1986年同期黄海浮游植物调查资料相比 ,1998年春季黄海浮游植物的种类组成和 1986年春季相似 ,但浮游植物的数量减少 64.6%。     

Inhibitory effects of seaweeds on histamine release from rat basophile leukemia cells (RBL-2H3)

ABSTRACT:   The effects of 80% methanol extracts from frozen samples of 41 macroalgae and one sea grass collected in the Ise-Shima region of Japan were investigated on histamine release from rat basophile leukemia cells (RBL-2H3) sensitized with antidinitrophenyl (DNP) IgE and stimulated with DNP-BSA. Of the 21 brown algae, five green and 15 red algae, and one sea grass tested, only extracts from seven brown algae suppressed histamine release from RBL cells, as determined by high-performance liquid chromatography (HPLC) analysis. When the cytotoxic effects of the seven brown algal extracts were investigated by Trypan blue staining, only Eisenia arborea and Sargassum thunbergii did not show cytotoxic effects. Therefore, we conclude that E. arborea and S. thunbergii may contain compounds that have antiallergic effects without inducing cell death.     

Outdoor phytoplankton continuous culture in a marine fish–phytoplankton–bivalve integrated system: combined effects of dilution rate and ambient conditions on growth rate, biomass and nutrient cycling

Natural phytoplankton populations were cultured in outdoor continuous cultures using fish-farm effluents as the source of nutrients. The dilution rate was assumed to be the integrating factor of phytoplankton growth and biomass development (flux and stock). In this context, the combined effects of (i) dilution rates of the outdoor culture and (ii) ambient conditions were tested on phytoplankton growth, biomass and cycling of the major nutrient elements (C, N and P). Experiments were carried out in outdoor polyester tanks (0.7 m deep), homogenised by gentle aeration. Si/P ratio was balanced at around 5 in the inflow in order to induce diatom domination while maintaining high N and P assimilation by phytoplankton. Nutrient cycling was assessed through analyses of the different forms of particulate and dissolved nutrients in the inflow and the outflow. Culture dilution rates determined the longevity of the culture and the assimilation efficiency of nutrients. Dissolved phosphorus was the most limiting nutrient. The optimal dilution rate was approximately 0.5 day⁻¹ at 10 °C and 1.5 day⁻¹ at 20 °C with a mean diatom biomass of 9 μM P. Under these conditions, 80% of the dissolved nutrients provided to the tanks were transformed, a production of 8 g C m⁻² day⁻¹ and an assimilation rate of 0.3 g P m⁻² day⁻¹ were recorded. Assimilation by diatoms was the major pathway of nutrient cycling. During the experiment, a bottom sediment developed progressively and this also played an important role in denitrifying the excess dissolved nitrogen in the fish-farm effluent. However, the results showed that diatom biomass can collapse and we hypothesize that this was the consequence of an increase in cellular sinking rates due to cell aggregation under nutrient or light stress. Modelling approaches are needed in future research in order to determine optimal dilution rates taking into account phytoplankton growth rates, nutrient inputs and ambient conditions (e.g. light and temperature).     

Effect of dietary defatted diatom biomass on egg production and quality of laying hens

Background： This study was to determine if feeding laying hens with defatted diatom microalgal biomass （DFA） from biofuel production affected their egg production and health status. Methods： Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio （FCR）, rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health. Results： The15% DFA diet decreased （P 〈 0.05） feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased （P 〈 0.05） egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent （P 〈 0.05） changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health. Conclusions： Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.     

长江云阳江段四大家鱼产卵场浮游植物初步调查

四大家鱼繁殖期间 ( 2 0 0 2年 5月至 6月 )对云阳江段产卵场浮游植物进行了调查 ,结果表明 :浮游植物生物量为 0 .5 0 6 75mg L ,其中硅藻为优势种群。其浮游植物种类组成和数量与江河汛期水文状况有明显关系。     

Effect of organic fertilizer on plankton primary productivity in fish ponds

The effect of cattle organic fertilizer on plankton primary production and related variables was tested in six Bulgarian fish ponds situated close to the town of Plovdiv in Bulgaria. At the beginning of the experiment (16th of May 2004, about 10 days after filling with water) a suppression of plankton metabolism was observed and after that the ponds treated with manure demonstrated significantly higher productivity than the controls, especially during the transition to the autumn season when the water column was more regularly mixed. The other measured variables (Secchi disk readings, plankton chlorophyll-a and respiration, assimilation number per unit chlorophyll-a) did not show significant differences between the treated and control ponds.     

大力加湖鲟鱼放养场浮游植物及鱼产潜力

2004年5、7、9、12月对大力加湖浮游植物的种类组成结构特征进行了研究。结果表明：大力加湖鲟鱼放养场浮游植物96个种属,密度255.54×10~4 ind．/L,生物量14.166 mg/L。浮游植物季节变化比较明显,密度秋季最高为456.160×10~4 ind．/L,生物量以秋季最高30.105 mg/L。多样性指数变化是夏季＞秋季＞冬季＞春季；均匀度指数变化是冬季＞夏季＞秋季＞春季。全库总鱼产潜力527760 kg,总放养量2804800尾。     

Low-density silver carp Hypophthalmichthys molitrix (Valenciennes) polyculture does not prevent cyanobacterial off-flavours in channel catfish Ictalurus punctatus (Rafinesque)

Silver carp Hypophthalmichthys molitrix (Valenciennes) were co‐cultured with channel catfish Ictalurus punctatus (Rafinesque) in 0.4 ha earthen ponds to determine the impacts of carp grazing on pond phytoplankton communities and cyanobacterial off‐flavours in catfish. Carp were stocked at densities of 0, 75, or 250 fish ha^?1 in seven replicate ponds per treatment. The mean chlorophyll a concentrations (a measure of phytoplankton standing crop) steadily increased in all treatments from about 100 μg L^?1 in April to more than 400 μg L^?1 by mid‐October. Silver carp had no affect (P>0.1) on chlorophyll a concentrations across all sampling dates (April though October) or for sampling dates late in the growing season (August–October) when the prevalence of cyanobacterial off‐flavours among catfish populations is usually greatest. Silver carp did not eliminate odour‐producing cyanobacteria from pond phytoplankton communities: on sampling dates in September and October, three to six ponds in all treatments contained populations of the odour‐producing cyanobacteria Oscillatoria perornata, Anabaena spp., or both. Failure of silver carp to eliminate odour‐producing cyanobacteria resulted in a relatively high incidence in all treatments of ponds with off‐flavoured catfish. On sampling dates in September and October, catfish in three to five ponds in each treatment were tainted with either musty (2‐methylisoborneol) or earthy (geosmin) off‐flavours. The presence of silver carp had no obvious effect on off‐flavour intensity: on each sampling date, at least three ponds in each treatment contained catfish described as distinctly to extremely off‐flavored. Apparently, hypertrophic conditions in catfish ponds overwhelm the effect of silver carp grazing at the low carp densities used in this study.     

超声波在水产养殖中的应用

超声波具有机械传质、加热和空化作用。高强度的超声会破碎生物的细胞,降低酶活性等;合适的低强度超声波可以促进鱼卵孵化,提高鱼类的生长速度,去除有害藻类,并能增强鱼类的免疫功能,有利于鱼病防治。     

Antiplatelet and Anticoagulant Effects of Diterpenes Isolated from the Marine Alga,Dictyota menstrualis

Cardiovascular diseases represent a major cause of disability and death worldwide. Therapeutics are available, but they often have unsatisfactory results and may produce side effects. Alternative treatments based on the use of natural products have been extensively investigated, because of their low toxicity and side effects. Marine organisms are prime candidates for such products, as they are sources of numerous and complex substances with ecological and pharmacological effects. In this work, we investigated, through in vitro experiments, the effects of three diterpenes (pachydictyol A, isopachydictyol A and dichotomanol) from the Brazilian marine alga, Dictyota menstrualis, on platelet aggregation and plasma coagulation. Results showed that dichotomanol inhibited ADP- or collagen-induced aggregation of platelet-rich plasma (PRP), but failed to inhibit washed platelets (WP). In contrast, pachydictyol A and isopachydictyol A failed to inhibit the aggregation of PRP, but inhibited WP aggregation induced by collagen or thrombin. These diterpenes also inhibited coagulation analyzed by the prothrombin time and activated partial thromboplastin time and on commercial fibrinogen. Moreover, diterpenes inhibited the catalytic activity of thrombin. Theoretical studies using the Osiris Property Explorer software showed that diterpenes have low theoretical toxicity profiles and a drug-score similar to commercial anticoagulant drugs. In conclusion, these diterpenes are promising candidates for use in anticoagulant therapy, and this study also highlights the biotechnological potential of oceans and the importance of bioprospecting to develop medicines.