水杨酸对浒苔生长和生理特性的影响

为探讨水杨酸(SA)对不同增殖方式来源的浒苔生长和生理特性的影响,本文选取营养繁殖得到的浒苔(VU)和孢子/配子繁殖得到的浒苔(SU)作为供试材料,设置不同的水杨酸浓度,测定两种浒苔的生长、叶绿素荧光、超氧化物歧化酶(SOD)和可溶性蛋白含量等生理指标.结果表明: 低浓度水杨酸可以促进VU和SU的生长,对VU促进效果更为显著;在0.2 μg·mL^-1水杨酸浓度下,VU相对生长速率达到最大值21.0%,且与SU相比,VU最大光化学效率提高了9.8%.水杨酸对两种浒苔的SOD活性影响较大,在水杨酸浓度为0.2、0.5 μg·mL^-1下,VU的SOD活性增幅分别达52.0%、198.6%,SU的SOD活性增幅分别达54.1%、38.0%.水杨酸促进了浒苔的相对电子传递速率、光合作用和蛋白质含量.水杨酸对两种增殖方式来源的浒苔的生长均有促进作用,尤其是对VU的促进作用更为明显.     

Morphological changes of giant mitochondria in the unicellular to multicellular phase during parthenogenesis of Ulva partita (Ulvophyceae) revealed by expression of mitochondrial targeting GFP and PEG transformation

A giant mitochondrion that branches and connects as a single mitochondrion in a cell has been observed during specific phases of the cell cycle of unicellular green algae, but has not been observed in multicellular algae. The genus Ulva is a green macroalga in which the haploid and diploid phases are isomorphic and its gametes develop parthenogenetically. The existence or absence of the giant mitochondrion, and its behavior in Ulva partita, were investigated using a parthenogenesis system. To observe the parthenogenesis of gametes and the dynamics of mitochondria by fluorescence microscopy, we developed an experimental system for culturing and observing U. partita on cover slips: gametes were suspended in 6‐well plates filled with artificial seawater, and cover slips were placed on the well bottoms. The gametes settled on the cover slips as spherical cells (1‐cell S phase). These cells grew into larger cells, losing their eyespot (1‐cell L phase), and developed into multicellular thalli. Gene introduction using the polyethylene glycol (PEG) method is available with transformation efficiencies of 9.0–15.1%. Transformation was performed using a plasmid encoding green fluorescent protein (GFP) fused to the mitochondrial targeting sequence, and mitochondria were labeled by GFP fluorescence. This revealed a string‐shaped giant mitochondrion in a cell of the 1‐cell S phase. In the 1‐cell L phase, a reticular mitochondrion was observed. After the initiation of cell division, the reticular mitochondrion was fragmented, and small oval mitochondria were observed in the 5‐cell phase.     

Freshwater population of Ulva flexuosa (Ulvaceae,Chlorophyta) as a food source for great pond snail: Lymnaea stagnalis (Mollusca,Lymnaeidae)

Cosmopolitan species of the genus Ulva (Ulvaceae; Chlorophyta) that populate the littoral zone of marine habitats constitute a staple diet for a variety of organisms, particularly snails, shellfish, polychaetes, and birds. Occurrence of Ulva species (e.g., U. flexuosa and U . prolifera) has also been observed in freshwater inland ecosystems that have no contact with saline water. However, the influence of the development of macroalgal mats of Ulva on indigenous organisms in limnic ecosystems has not been established. This study investigates the trophic relationships between Ulva flexuosa and one species of snail from freshwater habitats in central Europe. During the summer, the great pond snail (Lymnaea stagnalis) consumed Ulva as a source of nutrition even when other algae and plants were available. Lymnaea stagnalis consumed an average of 100 mg of Ulva thalli per day. This level of biomass exceeded the consumption of an alternative food source, the shoots of Elodea canadensis. Ulva thalli are more actively consumed by great pond snails than Elodea shoots, and this is expressed in terms of the differences of biomass consumption. It was also observed that the interior of the monostromatic tubular thalli of Ulva flexuosa serves as a protective shelter for juvenile great pond snails.     

Stabilization of mitochondrial and microsomal function by polysaccharide of Ulva lactuca on D-Galactosamine induced hepatitis in rats

In this study we used liver mitochondrial and microsomal fraction from rats pretreated with seaweed Ulva lactuca polysaccharide extract (ULP - 200 mg/kg body weight, daily for 21 days, oral gavage) on D-Galactosamine (500 mg/kg body weight, intraperitoneally) challenge. Effectiveness of ULP was determined based on functional status of trichloro acetic acid (TCA), urea cycle, and microsomal enzymes. The composition of sulfate polysaccharide content such as total sugars, sulfate and uronic acid were examined. In addition the fine ultra structural changes were examined using electron microscopy (EM). We observed significant (p < 0.001) mitochondrial and microsomal abnormalities during liver damage by D-Galactosamine, consequently altering enzymes of energy metabolism. Electron microscopy of D-Galactosamine intoxicated rat liver tissue revealed the swelling and loss of mitochondrial cristae. Conversely the rats pretreated with ULP against D-Galactosamine challenge prevented (p < 0.05) the significant abnormality of TCA, microsomal enzymes and severity of mitochondria as observed in EM study in rats injected with D-Galactosamine alone. However no effective prevention was observed in urea cycle enzymes among D-Galactosamine and treatment group rats. These results showed the effectiveness of ULP in stabilizing the functional status of mitochondrial and microsomal membrane which might be due to the presence of sulfated polysaccharide that could prevented the oxidative stress induced by D-Galactosamine intoxication.     

Microelement composition of the green alga Ulva fenestrata from Peter the Great Bay, Sea of Japan

Concentrations of heavy metals Fe, Mn, Cu, Zn, Pb, Cd, and Ni were determined in the thalluses of the green alga Ulva fenestrata sampled from different locations in Peter the Great Bay (Sea of Japan). According to the metal concentrations in Ulva, the degree of pollution of the surveyed areas in Peter the Great Bay decreases in the following series: Amur Bay > Ussuri Bay > Nakhodka Bay > Vostok Bay > the water area of Far Eastern State Marine Nature Biosphere Reserve. The microelement composition of Ulva from open-shore stations reflects the heavy metal pollution level of water areas as a whole. The concentrations of trace elements in U. fenestrata from closed coastal areas are indicative of marine coastal water pollution from local sources. Generally, metal concentrations in U. fenestrata from Peter the Great Bay are similar to heavy metal levels in non-polluted or weakly polluted coastal areas of the world.     

Edible macroalga <Emphasis Type="Italic">Ulva prolifera</Emphasis> as microelemental feed supplement for livestock: the fundamental assumptions of the production method

In the present paper, the possibility of the application of marine macroalga Ulva (Enteromorpha) prolifera, as microelemental feed supplement for livestock, was evaluated. The concept was based on two facts: the natural macroalga contains high concentrations of microelements and there is a possibility to greatly increase this content via biosorption. In order to characterize the biosorption process of metal ions by U. prolifera, preliminary experiments were conducted with Cr(III) ions. The effect of temperature, pH and the biomass concentration on the equilibrium of biosorption was investigated. For further experiments (biosorption of Mn(II), Zn(II), Cu(II), Co(II)), the following experimental conditions were chosen: pH 5, 25°C, the biomass concentration 1.0 g l⁻¹. Equilibrium of the biosorption process could be described by the Langmuir equation. The theoretical maximum biosorption capacity was also determined by potentiometric titration of the biomass. The investigation of the external structure of the macroalga and atomic concentration of elements on the surface of the biomass was analyzed using scanning electron microscopy. The content of microelements in the biomass after biosorption increased 110,555; 44,228; 21,177; 2,281 and 1,458 times for Co(II), Cr(III),Cu(II), Zn(II), Mn(II), respectively. Therefore, biomass of U. prolifera enriched with individual microelements, mixed in the proper proportion could be used as feed supplement in animal feeding to cover the nutrient requirements for microelements.     

孔石莼(Ulva pertusa)凝集素的分离纯化及性质的研究

为抑制肿瘤细胞增殖和防治有关病害提供基础理论依据 ,将孔石莼 (Ulva pertusa)经磷酸盐缓冲液抽提 ,2 0 %～ 75%硫酸铵分级沉淀 ,牛甲状腺球蛋白 - Sepharose4B亲和层析 ,可以从绿藻孔石莼中纯化出孔石莼凝集素 (UPL) ,在 PAGE上显示单一蛋白染色带 ,在等电聚焦电泳上显示单一蛋白染色带 ,其 p I为 8.40 .纯化后的 UPL的最大紫外吸收峰在 2 85nm,用 Sephadex G- 2 0 0分子筛层析测得其分子量为 1 1 0 4 7.该凝集素可以凝集人的 A、B、AB、O型红细胞 ,且凝集活性相同 ,在对人 (A、B、AB、O)兔、鲤、鲫的红细胞的凝集作用中 ,兔的凝集作用最强 .该凝集素凝集兔红细胞的作用不被 D-半乳糖、D-果糖、葡萄糖、蔗糖、甘露聚糖、γ球蛋白、卵清蛋白所抑制 ,仅被牛甲状腺球蛋白抑制 ,最小抑制浓度为 6.2 0 g/L.该凝集素在 p H4.0～ 1 0 .1 4范围内均有活性 ,但在p H6.50～ 9.51范围内活性较高 ,该凝集活性在 85℃加热 1 h,活力仍未改变 ,说明具有很强的耐热性 .     

Ecological studies on Ulva lactuca L. from Veraval,India

Ulva lactuca L., at Veraval (20° 54N and 70° 22E) on the western coast of India, grows in the intertidal belt from June to late February. During the summer months of March, April and May, the species dries up, leaving rhizoidal fragments for perennation. High values of density, phytomass, frequency, weight, and volume have been recorded during September and January. Accumulation of phytomass appears to be chiefly density dependent. High dissolved oxygen content and low temperatures of the surface sea water favoured enhanced growth and, consequently, more phytomass.     

Nitrate uptake and storage in the seaweed Ulva rigida C. Agardh in relation to nitrate availability and thallus nitrate content in a eutrophic coastal lagoon (Sacca di Goro, Po River Delta, Italy)

The seasonal cycle of biomass and tissue composition of Ulva rigida C. Agardh, in relation to nitrogen availability in the water column, was studied in 1991-1992 in the Sacca di Goro, a highly eutrophic lagoon in the Po River Delta (Italy). Nitrate uptake rates and storage capacity were also determined in laboratory experiments. The seasonal growth of U. rigida was related to the seasonal trend of nitrogen concentration in the water column. U. rigida biomass increased exponentially during spring and attained peaks of about 300-400 g dry mass (DM) m⁻² in June. As biomass increased, U. rigida depleted nitrate in the water column. Thallus nitrate reserves also declined from 100 μmol N (g DM)⁻¹ to almost undetectable levels, and total thallus nitrogen declined from 4% to 2.5% DM and 1.25% DM in 1991 and 1992, respectively. During summer, U. rigida decomposition increased, and organic nitrogen concentrations in the water column increased. The uptake experiments demonstrated an inverse relationship between thallus nitrate content and nitrate uptake rates. A modified Michaelis-Menten equation that accounts for thallus nitrate fit the uptake data well. U. rigida can accumulate up to about 400-500 μmol nitrate (g DM)⁻¹ in cellular reserves. U. rigida in the Sacca di Goro has higher K_m and lower V_max/K_m ratios for nitrate uptake than other chlorophycean species, indicating a low efficiency of uptake at low nitrate concentrations. This low uptake efficiency, and the ability to exploit N availability by storing cellular nitrate pools in excess of immediate growth needs, may represent a physiological response to an eutrophic environment where nitrate is in large supply for most of the year.