Production of algal gels from the brown alga, <Emphasis Type=Italic>Laminaria japonica</Emphasis> Aresch., and their biotechnological applications

Alginic acid is localised in the cell walls and intercellular spaces of the brown alga, Laminaria japonica Aresch., and the salts of this compound occur mainly as calcium alginates. However, the alginates in this alga do not have the viscosity and the ability to create and stabilise structural products. Hence, the structure and properties of the alginates in Laminaria were changed by chemical modification to produce new products such as sodium alginates and other substances capable of forming gels. The rheological properties of the algal gel from Laminaria depended on the properties of the sodium alginate. Heating the algal product up to 90°C did not change its physical and chemical properties; the viscosity did not differ from that of the initial product. The viscosity and molecular weight of the sodium alginate isolated from the algal gel were stable from 20°C up to 95°C. However, about 30% of the viscosity was lost at 100°C. Recipes and various methods of preparing the gel products as fish sauces, jelly-like fish products, fruit jellies, drinks, cosmetic and pharmaceutical products are presented. The algal gel and the gel products did not lose their integrity with heat processing. Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines.     

Plant regeneration from protoplasts of Laminaria japonica Areschoug (Laminariales, Phaeophyceae) in a continuous-flow culture system

A continuous-flow culture system was developed for culturing Laminaria japonica protoplasts. Protoplasts were settled on 5-μm pore size nylon mesh fixed inside a 50-ml plastic syringe, and cultured in Provasoli's enriched seawater with iodine medium with a gentle upward flow generated by a peristaltic pump. In the culture system, 50% of the protoplasts regenerated their cell wall within 24 hours and almost all protoplasts regenerated a cell wall after 3 days culture. After cell wall regeneration, a number of cells divided and regenerated into sheet-shaped thalli. The thalli transferred to a tissue culture flask developed into sporophyte-like plantlets within 1 month. Plantlets then differentiated into blade, stipe, and holdfast, with a proper mucilage canal. Received: 21 April 1997 / Revision received: 27 June 1997 / Accepted: 5 July 1997     

Fucoidan Isolated from Laminaria angustata var. longissima Induced Macrophage Activation

We investigated macrophage activation by fucoidan from Laminaria angustata var. longissima in a murine macrophage cell line, RAW 264.7. The ratio of the chemical composition of the fucoidan was L-fucose:D-galactose:D-glucose:D-xylose:uronic acid:sulfate = 1.00:0.54:0.08:0.08:0.64:0.87. The fucoidan induced production of nitric oxide, tumor necrosis factor-α, and interleukin-6 in RAW 264.7 cells. These results indicate that the fucoidan induced macrophage activation.     

THE OCCURRENCE OF FLAGELLATED EGGS IN LAMINARIA ANGUSTATA (PHAEOPHYTA,LAMINARIALES)1

Eggs of laminaria angustata Kjellman were shown to have two flagella. Compared with flagella of other phaeophycean swarmers, those of Laminaria eggs have several unique characters such as lack of mastigonemes, widely spaced basal bodies and no flagellar rootlets. The flagella abscise during egg liberation.     

Extracellular Accumulation of DNA by Hydrocarbon-utilizing Bacteria

Some hydrocarbon-utilizing bacteria grown on n-paraffin as the sole source of carbon accumulated extracellularly a considerable amount of DNA (0.1 g to 0.6 g per liter) which was free from intact cells and slime materials. This was particularly noted when the strains belonging to Pseudomonad were employed. n-Paraffin was a preferable carbon source for the accumulation of DNA by Pseudomonad, while a strain of Arthrobacter accumulated DNA by growing it on glucose.

The DNA thus accumulated was easily isolated and purified free from other cellular components. The purified DNA was highly polymerized (above 4 × l0⁶ daltons), having the same base composition as the cellular DNA.     

cAMP AND cAMP-STIMULATED PROTEIN PHOSPHORYLATION IN ZOOSPORES OF BROWN ALGAE1

Adenosine 3′,5′-cyclic monophosphate (cAMP) and guanosine 3′,5′-cyclic monophosphate (cGMP) were detected at concentrations of 8–11 and 10–20 pmol · mg^?1 protein, respectively, in zoospores of a brown alga, Undaria pinnatifida (Harvey) Suringer. Cellular levels of these cyclic nucleotides did not substantially change during dark to light transition. cAMP-stimulated protein phosphorylation was found in soluble cell-free extracts of zoospores of Undaria pinnatifida and Laminaria angustata Kjellman.     

海带喇叭丝对接的新类型

在对海带髓部组织进行显微观察时,发现了两种海带喇叭丝对接的新类型,即三细胞对接型和四细胞对接型。这两种类型的数量较少,只存在于带片与带柄的交接处,其功能可能与提高物质转运效率和横向运输有关。     

Direct determination of alginate content in brown algae by near infra-red (NIR) spectroscopy

The methods used to quantify total alginate in brown algal tissue are time-consuming and may also be misleading, so faster and simpler methods for measuring alginate content would be beneficial in a variety of applications. This study reports on the use of near infra-red (NIR) analysis to monitor the alginate content of Laminaria hyperborea stipe during biodegradation. NIR reflectance spectra were recorded for 78 different freeze-dried samples of its stipe. The samples were collected during several biological degradation experiments and the total alginate content varied from 2.2 to 40.8% Na-alginate (w/w), determined by established methods based on ion exchange. Data analysis was performed using multivariate calibration methods in order to relate the spectral data to the alginate content. PLS2 analysis revealed some dependence on material type, probably reflecting differences in polyphenol content. In the end, a PLS1 model with 9 components was selected. The calculated model was validated both with internal data and with an external test set. Internal full cross validation explained 96.6% of the variance in alginate content. The external validation showed that the PLS1 model was able to predict the alginate concentration with a root mean square prediction accuracy of 2.1%. This revised version was published online in June 2006 with corrections to the Cover Date.     

海带无性繁殖系的形成及孢子体诱导

海带无性繁殖系的形成及孢子体诱导周志刚吴超元（中国科学院海洋研究所青岛２６６０７１）海带（Ｌａｍｉｎａｒｉａ）是具异型世代交替的大型经济褐藻,在生活史中出现一至数个细胞组成的雌、雄配子体阶段,再由雌配子体的卵囊受精长成孢子体［１］。现行的育苗法是于初...     

海带藻际微生物抗菌活性及其多样性的初步研究

从浙江台州海域健康海带、病烂海带(Laminaria japonica)及其周围海水中分离纯化海带藻际微生物, 利用双层琼脂扩散法对获得的菌株进行抗菌活性筛选, 比较活性菌株与来源的相关性, 并对具有抗菌活性的菌株进行16S rRNA系统发生学分析。结果显示, 在分离的143株海带藻际微生物中, 有42株细菌具有抗菌活性, 其中来源于健康海带和海水的活性菌株比例(35%和29%)大于来源于病烂海带的细菌(23%)。对其中16株具有广谱抗菌活性的菌株进行的16S rRNA系统发生学分析显示, 分别属于Pseudoalteromonas、Rahnella、Donghaeana、Bacillus和Exiguobacterium 5个属。为从藻际微环境的微生物多样性入手了解海带病烂机制以及寻找新的抗菌药物提供研究材料。     

Formation of Aldehyde Flavor (n-hexanal, 3Z-nonenal and 2E-nonenal) in the Brown Alga, Laminaria Angustata

2E-Nonenal and n-hexanal are the major and minor flavor compounds in the edible brown alga, Laminaria angustata, respectively. They are believed to characterize the flavor of this alga. However the metabolism of the two compounds is not precisely known. The pathways were clarified by elucidation of the intermediate structure through purification of the intermediate compounds from an enzymatic reaction and identification using HPLC and GC-MS techniques. Formation of n-hexanal, 3Z-nonenal and 2E-nonenal are proposed to be via two cascades from unsaturated fatty acids. They are C18:2(n-6), linoleic acid cascade and C20:4(n-6), arachidonic acid cascade through their hydroperoxides as intermediates by the lipoxygenase/fatty acid hydroperoxide lyase pathway.     

温度对海带幼孢子体生长和光合作用的影响

根据欧盟项目的总体研究计划 ,在室内和围隔实验中研究了海带幼孢子体在不同温度条件下的生长情况和光合作用曲线 ,得出幼孢子体在 15°C下生长情况最好 ,而且其长度和重量的日增加量均和温度有线性相关关系。 Pm 值在 15℃时为 5 79mol O2 / (g DW· h) ,围隔实验中为 6 4 2 (mol O2 / (g DW· h)。由于围隔实验海区的光照强于室内 ,使得围隔中海带的光合作用曲线其光饱和点高于室内实验海带的光饱和点。海带光饱和参数 (Ik)与温度有线性相关关系 (R2 =0 .736 7,p<0 .0 5 )。5℃时 ,Ik 值平均为 96μE/ (m2 · s) ,10℃时为 71μE/ (m2 · s) ,15℃时为 31μE/ (m2 · s)。呼吸速率 R值在 5℃时最低 ,为 5 4μmol O2 / (g DW·h) ,10℃、15℃和围隔中均高于 5℃时的呼吸速率 ,并且在 10℃达到最高。本次实验研究得出的生长和光合作用参数将有助于合理确定桑沟湾中海带的养殖容量。     

Microsatellite DNA Variation of the Gametophyte Clones Isolated from Introduced Laminaria japonica （Phaeophyta） and L. Iongissima of China and Varieties Derived from them

The variation of 90 Laminaria gametophyte clones representing the introduced Laminaria japonica （Group 1） and Laminaria Iongissima （Group 2）, the varieties of L. japonica （Group 3） and the varieties derived from interspecific hybrids （Group 4） was determined with 18 microsatellite markers. The allelic diversity and Nei＇s gene diversity of Group 1 were significantly higher than those of Group 2 （2.9 vs. 1.8 and 0.414 vs. 0.161, respectively）, demonstrating that the variation of the introduced L. japonica is richer than that of L. Iongissima. Both allelic diversity and Nei＇s gene diversity of Group 3 were lower than those of Group 1, indicating that only a portion of variation of L. japonica was incorporated into the varieties of L. japonica. Significant genetic differentiation was detected between four groups and between female （Population 1 ） and male （Population 2） gametophyte clones in each group. The variation among groups accounted for 39.95%, while that among populations accounted for 21.65% of the total. The genetic distance between Group 1 and Group 4 was obviously longer than that between Group 2 and Group 4 （0.686 vs. 0.291）, indicating that maternal gametophyte clone contributed more variation to the hybrids than the paternal gametophyte clone did.     

搅拌式光生物反应器培养海带配子体细胞:不同脉冲补料方式的研究

本文以批次培养为对照,研究了七种脉冲补料方式对搅拌式光生物反应器中培养大型褐藻海带配子体细胞生长和培养液内氮磷营养盐消耗的影响,并首次探讨了脉冲补料方式下不同补料时间点和补料量的影响作用。培养条件设定为50 mg DCW (细胞干重) L-1接种密度、培养液为改良的APSW人工海水、光强60 µE m-2 s-1、光周期16/8 h L/D、通气速率和搅拌速率分别为50 mL min-1和100 rpm。结果表明少量补料利于细胞对氮磷的协同吸收,进而利于生物量扩增。当培养液内氮磷富足或耗尽时补料对于生物量大量生产效果甚微,可能由于氮磷吸收变缓、其储存现象显著,或是其吸收协同性降低。文中当细胞生长至对数中期开始频繁补加少量氮磷营养盐,即维持培养液内氮磷浓度在各自起始浓度的1/3至1/2之间,对生物量生产最有效,生物量增长倍数高达12.270倍。     

昆布（海带）对高脂血症大鼠血脂的调节作用和机制

目的：探讨昆布（海带）在实验性高脂血症大鼠中的降血脂作用和机制。方法：健康雌性Wistar大鼠40只,应用高脂饲料喂养方法建立高脂血症动物模型,海带粉饲料喂养干预治疗。生化法检测大鼠血清甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）水平。硫代巴比妥酸法和硝酸还原酶法分别检测脂质过氧化物丙二醛（MDA）和一氧化氮（NO）含量,黄嘌呤氧化酶法和化学比色法分别测定超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-PX）活性。结果：经海带干预治疗后,动物血清TG、TC和LDL水平较模型组显著降低、HDL水平显著升高（P〈0.05）。治疗组动物血清和肝组织MDA和NO水平显著低于、而SOD和GSH-PX活性均显著高于模型组（P〈0.05）。结论：海带可能影响TG、TC、LDL和HDL等组分的代谢,通过增强抗氧化SOD和GSH-PX的活性,降低体内MDA和NO的水平,发挥调节血脂水平的作用。     

海带(Laminaria japonica)丝状体遗传多样性的比较研究

采用垂直板式聚丙烯酰胺凝胶电泳技术对分别来自中国青岛与日本北海道海带(Laminaria japonica)丝状体的6种酶系统（乙醇脱氢酶、谷氨酸脱氢酶、异柠檬酸脱氢酶、乳酸脱氢酶、山梨醇脱氢酶和超氧化物歧化酶）进行了检测,发现存在22个基因位点,分析了不同来源海带丝状体的遗传多样性与遗传分化程度。结果表明：日本北海道海带丝状体的预期杂合度、每个位点有效等位基因数等遗传参数均大于中国青岛海带丝状体。对日本北海道海带丝状体与中国青岛海带丝状体的遗传相似系数和遗传距离进行了计算分析,显示两者发生了遗传分化。日本北海道海带丝状体的遗传多样性高于中国青岛海带丝状体。研究结果还发现在中国青岛海带丝状体的Idh、Ldh 和Sdh中,以及日本北海道海带丝状体的Adh、Gdh、Idh、Ldh、Sdh和Sod中存在着不同迁移率的不等距双带酶,可能由特殊基因控制,并集中在第3个基因位点上。     

The response of the early developmental stages of Laminaria japonica to enhanced ultraviolet-B radiation

The responses of the early development of Laminaria japonica collected from Kiaochow Bay in China to enhanced ultraviolet-B radiation (UV-B, 280—320 nm) were studied in the laboratory. The low UV-B ra-diations (11.7—23.4 J·m-2·d-1) had no significant effects on zoospores attachment, but when the UV-B dose > 35.1 J·m-2·d-1 the attachment decreased significantly compared with the control. Germination of embryospores was >93% under the low (11.7—35.1 J·m-2·d-1) doses, and in the range of 78.5%—88.5% under the high (46.8—70.2 J·m-2·d-1) UV-B doses, indicating a significant radiation effect. Under the higher UV-B exposure (35.1—70.2 J·m-2·d-1), all of the few gametophytes formed from embryospores died 120 h post-release. After exposure to the low UV-B radiation (11.7—23.4 J·m-2·d-1), the formation of sporophytes decreased and the female gametophyte clones increased compared with the control. However, the sex ratio and the relative growth of female gametophytes/sporophytes had not signifi-cantly changed. According to the results, enhanced UV-B radiation has a significant effect on the early development of L. japonica under laboratory conditions, suggesting that the UV-B radiation could not be overlooked as one of the important environmental factors influencing the ontogeny of macroalgae living in marine ecosystems.     

昆布（海带）对高脂血症大鼠血脂的调节作用和机制

目的:探讨昆布(海带)在实验性高脂血症大鼠中的降血脂作用和机制。方法:健康雌性Wistar大鼠40只,应用高脂饲料喂养方法建立高脂血症动物模型,海带粉饲料喂养干预治疗。生化法检测大鼠血清甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL)和高密度脂蛋白(HDL)水平。硫代巴比妥酸法和硝酸还原酶法分别检测脂质过氧化物丙二醛(MDA)和一氧化氮(NO)含量,黄嘌呤氧化酶法和化学比色法分别测定超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-PX)活性。结果:经海带干预治疗后,动物血清TG、TC和LDL水平较模型组显著降低、HDL水平显著升高(P<0.05)。治疗组动物血清和肝组织MDA和NO水平显著低于、而SOD和GSH-PX活性均显著高于模型组(P<0.05)。结论:海带可能影响TG、TC、LDL和HDL等组分的代谢,通过增强抗氧化SOD和GSH-PX的活性,降低体内MDA和NO的水平,发挥调节血脂水平的作用。