砷在铜藻中的亚细胞分布及细胞壁吸附作用研究

为揭示铜藻(Sargassum horneri)细胞壁在砷(As)生物吸附中的作用,以铜藻幼苗为研究对象,测定了不同As胁迫浓度(50、100、150、200、250μmol·L^-1)下细胞亚组分中的As含量变化,并对细胞壁的吸附动力学、细胞壁多糖As吸附效果以及细胞壁多糖傅里叶红外光谱进行了分析研究。结果表明：在低浓度(50μmol·L^-1)As胁迫时,50.0%的As分布于细胞壁,明显高于其他组分;而在高浓度(≥150μmol·L^-1)As胁迫时,As优势分布由细胞壁转向细胞可溶组分,细胞壁中的As比例下降至36.4%～37.3%。随着As胁迫浓度升高,细胞壁As含量呈上升趋势,当As胁迫浓度超过100μmol·L^-1时,细胞壁As含量上升趋于平缓。细胞壁吸附动力学实验表明酯化改性和甲基化改性可降低细胞壁As吸附的平衡容量,其降幅分别为68.5%和42.9%,同时细胞壁多糖红外光谱分析结果也表明羟基、氨基、羧基、硫酸盐基等官能团为细胞壁As吸附提供了结合位点。细胞壁多糖体外吸附实验表明随着多糖浓...     

环境因子对瓦氏马尾藻吸收溶解性无机碳及提升海水pH的影响

探讨了温度、光照强度以及氮、磷加富对瓦氏马尾藻(Sargassum vachellianum)溶解性无机碳(DIC)吸收及提升海水pH能力的影响。结果表明:(1)温度、光照强度对瓦氏马尾藻的DIC吸收速率及海水pH提升速率影响显著(P0.05),在光照强度60μmol/(m2·s)、温度20℃条件下,瓦氏马尾藻对DIC吸收速率和海水pH提升速率最大,分别高达82.14μmol/(g·h)和0.138/(g·h),当环境条件低于或高于这一阈值,藻体对DIC吸收和海水pH提升能力均有不同程度的降低;(2)氮、磷加富能够显著提高瓦氏马尾藻DIC吸收及提升海水pH能力(P0.05),高氮、磷(HNP)组藻体对DIC吸收及提升海水pH能力均显著高于低氮、磷(LNP)组(P0.05),且N、P的添加对增加藻体吸收DIC及提升海水pH的能力具有促进作用。该研究为利用瓦氏马尾藻增养殖技术进行近岸富营养化及藻场退化海域生态修复及减缓海洋酸化提供了理论依据。     

大型海藻养殖对水体DO含量的影响

为了解大型海藻养殖对海水DO含量的影响,明确其在光照、黑暗及光暗交替条件下海水DO含量的变化过程。笔者将取自温州洞头近海养殖的鼠尾藻、羊栖菜带至实验室内进行养殖实验,设置光照（2、6、12 h）、黑暗（2、6、12 h）、光暗交替（1 h 1 h、6 h 6 h、12 h 12 h）处理,测定养殖水体DO含量,对其产氧速率、耗氧速率等进行分析。结果表明：随着光照时间的延长,鼠尾藻、羊栖菜产氧速率都逐渐下降,鼠尾藻的产氧速率比羊栖菜高（P<0.05）;黑暗条件下,鼠尾藻耗氧速率在6 h时达最高288.02 mg/kg DW?h,羊栖菜耗氧速率在2 h时达最高207.46 mg/kg DW?h,鼠尾藻的耗氧速率比羊栖菜高;光暗交替下鼠尾藻的净产氧速率先急剧降低后缓慢升高,短光暗交替周期（1 h 1 h）时净产氧速率最高457.08 mg/kg DW?h。羊栖菜净产氧速率先升高后降低,在中光暗交替周期（6 h 6 h）时最高64.04 mg/kg DW?h。大型海藻养殖时随着光暗环境的交替进行,不断发生着光合产氧、暗呼吸耗氧的转换,总体而言海藻养殖提高了水体DO含量。大型海藻养殖的生态、社会价值显著,建议大力推广     

微波辅助提取羊栖菜多酚的工艺研究

以羊栖菜为原料,在单因素试验的基础上,采用四因素三水平正交试验设计,优选微波辅助提取羊栖菜多酚的最佳工艺条件：乙醇体积分数80%,微波功率600 W,浸提温度70℃,料液比1∶10 g·mL-1,浸提时间4 min,此条件下羊栖菜多酚得率可达233%。     

Damage to the Membrane Permeability and Cell Death of Vibrio parahaemolyticus Caused by Phlorotannins with Low Molecular Weight from Sargassum thunbergii

ABSTRACT

To understand the mode of action of low molecular weight phlorotannins (LMPs) from Sargassum thunbergii against Vibrio parahaemolyticus, effects of LMPs on the growth curve and the content changes of some substances in culture media were investigated, and those on morphological and ultramicrostructure were also observed by scanning electron microscope and transmission electron microscopy. The results showed that LMPs inhibited thalli growth at logarithmic phase and damaged the cell membrane and cell wall of tested bacteria which led to the leakage of cytoplasm and the deconstruction of membrane permeability. The present study indicates that LMPs as natural products in seaweeds deserve further investigation for food safety control and aquacultural drugs.     

Effect of Oversulfation on the Composition,Structure, and In Vitro Anti-Lung Cancer Activity of Fucoidans Extracted from Sargassum aquifolium

Intensive efforts have been undertaken in the fields of prevention, diagnosis, and therapy of lung cancer. Fucoidans exhibit a wide range of biological activities, which are dependent on the degree of sulfation, sulfation pattern, glycosidic branches, and molecular weight of fucoidan. The determination of oversulfation of fucoidan and its effect on anti-lung cancer activity and related signaling cascades is challenging. In this investigation, we used a previously developed fucoidan (SCA), which served as a native fucoidan, to generate two oversulfated fucoidan derivatives (SCA-S1 and SCA-S2). SCA, SCA-S1, and SCA-S2 showed differences in compositions and had the characteristic structural features of fucoidan by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses. The anticancer properties of SCA, SCA-S1, and SCA-S2 against human lung carcinoma A-549 cells were analyzed in terms of cytotoxicity, cell cycle, Bcl-2 expression, mitochondrial membrane potential (MMP), expression of caspase-3, cytochrome c release, Annexin V/propidium iodide (PI) staining, DNA fragmentation, and the underlying signaling cascades. Our findings indicate that the oversulfation of fucoidan promotes apoptosis of lung cancer cells and the mechanism may involve the Akt/mTOR/S6 pathway. Further in vivo research is needed to establish the precise mechanism whereby oversulfated fucoidan mitigates the progression of lung cancer.     

大连沿海3种大型速生海藻的营养组成分析

对采自大连沿海的角叉菜（Ｃｈｏｎｄｒｕｓ ｏｃｅｌｌａｔｕｓ）、孔石莼（Ｕｌｖａ ｐｅｒｔｕｓａ）、海黍子（Ｓａｒｇａｓｓｕｍ ｋｊｅｌｌｍａｎｉａｎｕｍ）的营养组成进行分析。结果表明,这３种大型速生海藻的营养均衡齐全,均为高蛋白、低脂肪、低热量食品,并富含矿物质、人体必需的微量元素、氨基酸和脂肪酸。     

A Promising Potential of Brown Algae Sargassum polycystum as Irreversible Hydrocolloid Impression Material

This study aimed to investigate the potential use of brown algae Sargassum polycystum as irreversible hydrocolloid (alginate) impression material. Potassium alginate extracted from Sargassum polycystum was prepared in three different compositions (14%, 15%, and 16%) and mixed with other standard components to form an alginate impression material. Prior to that, the purity of potassium alginate was quantified with Fourier Transform Infrared Spectroscopy (FTIR) analysis. As a control material, the alginate impression material from a commercially available product was used. All alginate impression materials were then applied to a die stone model. Dimensional accuracy was measured by calculating the mesiodistal width of incisors in the generated dental cast using a digital caliper 0.01 accuracy (five replications). In addition, to evaluate the dimensional stability, the impression results were poured at four different periods (immediately, 5 min, 10 min, and 15 min). An independent t-test was performed to compare the measurement results with p < 0.05 considered significant. Analytical results confirm that the impression material containing 15% potassium alginate gives the best dimensional accuracy similar to control (p > 0.05). Meanwhile, the optimal dimensional stability was produced in the impression material containing 16% potassium alginate. Our study suggested that brown algae Sargassum polycystum has a promising potential to be used as an alginate impression material in clinical application.     

我国长江口及邻近海域铜藻生长和金潮分布变化特征

为了解金潮源头,对枸杞岛附近贻贝(Mytilus edulis)养殖区固着褐藻进行了分布特征调查,并对长江口附近海域漂浮金潮进行月度监测。结果表明,枸杞岛附近贻贝养殖区设施上固着生长大量褐藻马尾藻,1—3月,藻体具有固着器,营固着快速生长,平均长度在3月可达3.45 m;同时海区巡航监测结果显示,1—2月枸杞岛附近海域无漂浮马尾藻,3月份只有单棵零星漂浮藻体; 4月份,贻贝养殖区马尾藻固着器逐渐萎缩消失,导致藻体大量脱落进入海区,由于马尾藻具有气囊结构,能够保障藻体长期漂浮在海表面形成金潮;大面监测结果显示,4—5月海区漂浮褐藻生物量与分布范围快速增加,分布面积可达27761 km^2。分子生物学检测结果显示,固着褐藻和海区漂浮褐藻均为铜藻(Sargassum horneri)。本研究结果表明,3—4月浙江沿岸固着铜藻在人为和海流的共同作用下从贻贝养殖设施上脱落后营漂浮生活,生长聚集,并可能在风和海流作用下向北至黄海海域形成金潮,黄海金潮可能具有多溯源性质。