Effects of salinity downshock on dimethylsulfide production     

Takushi Niki  Miwa Shimizu  Ayako Fujishiro  Junji Kinoshita 《Journal of Oceanography》2007,63(5):873-877

During time-series observations in Sagami Bay, Japan, the concentration of dissolved dimethylsulfoniopropionate (DMSP_d), a precursor of dimethylsulfide (DMS), was negatively correlated with salinity. In the laboratory, low-salinity shock reduced DMS production rates of the natural bacterial community and induced rapid DMSP release from a dinophyte, Heterocapsa triquetra, suggesting that low-salinity shock reduced DMSP_d consumption but enhanced DMSP_d production, which agrees with the negative correlation between DMSP_d and salinity observed in Sagami bay. In addition, low-salinity shock did not affect DMSP lyase activity of H. triquetra. Low-salinity shock would increase the contribution from algae in DMS production, leading to an increase in potential DMS productivity in the environment.  相似文献   

大米草中生物活性物质的筛选   总被引：9，自引：1，他引：9       下载免费PDF全文

徐年军  严小军  徐继林  马红辉 《海洋科学》2005,29(3):17-19

大米草(Spartina anglica)是一种资源丰富的盐沼植物，目前已在中国沿海大量分布，综合开发利用大米草具有重要的生态意义和经济效益。利用硅胶柱层析方法分离大米草甲醇提取物，再分别用DPPH法、纸碟法和MTT法对大米草中40多个组分进行了抗氧化、抗细菌和抗肿瘤活性的筛选。结果得到抗氧化活性组分5个、抗菌活性组分2个、抗肿瘤活性组分3个。目前对其活性先导化合物的分离纯化研究正在进行中。  相似文献   

海洋木栖真菌抗菌活性的初步研究   总被引：6，自引：0，他引：6  

林昕  黄耀坚  胡志钰  郑忠辉  苏文金 《台湾海峡》2004,23(3):308-313

从福建厦门海沧、集美及漳州浮宫等地采集到的红树林等海洋潮间带的各种腐木样品中分离得到176株海洋木栖真菌,对其进行抗菌活性检测.其结果表明共有96株海洋木栖真菌对大肠杆菌、枯草杆菌及白色假丝酵母中的一种或多种拮抗指示菌具有抑制作用,占供测菌株总数的54.5%.在这些活性菌株中,红树源菌株拮抗比例为30.2%,非红树源菌株拮抗比例为69.8%.具有抗菌活性的菌株主要分布于15个属中,包括木霉Trichoderma、青霉Penicillium、拟青霉Paecilomyces和一些不产孢的分类群.某些稀有真菌如盘多毛孢Pestalotia、茎点霉Phoma也具有一定的抗菌活性.  相似文献   

肝素酶Ⅰ对合成的肝素五糖的酶解作用及对其抗Xa因子活性的影响     

于广利  管华诗  Jawed Fareed 《中国海洋大学学报(自然科学版)》2001,31(4):529-535

研究肝素酶Ⅰ(来源于Flavobacterumheparinase，EC4.2.2.7)对人工合成的且含有与抗凝血酶Ⅲ特定结合位点的肝素五糖(SHP)的酶解作用，并对酶解作用的动力学进行研究。利用强阴离子高效液相色谱(SAX-HPLC)对酶解混合物进行分离，利用质谱(ESIMS)和核磁共振波谱(1H-NMR)技术对得到的二糖和三糖的结构进行确证。研究结果表明，这种被作为肝素反向试剂的肝素酶Ⅰ可水解人工所合成的肝素五糖，从而使之丧失抗Xa因子活性。  相似文献   

Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers     

DOU Shuozeng  TSUKAMOTO Katsumi 《海洋学报(英文版)》2007,26(5):76-89

Under artificial LD cycles(6,12,18 L),the elvers of Japanese eel,Anguilla japonica,showed a 24 h cycle of locomotor activity rhythm being most active at light transitions:the eels' activity rose to a primary peak after lights-off,followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time,and then reached a secondary peak before lights-on.Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d.Moreover,their activity level at dark phase significantly increased as the light period was prolonged:higher activity levels during shorter dark period.However,the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions.The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system.In all the LD cycles,over 99% of the activity occurred in the dark phase,indicating that the eels were always nocturnally active no matter what time of day it might be.Under 12 L conditions,the eels' activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10~15 to 20~25 ℃.The activity rhythm pattern(i.e.,two peaks occurring around light transitions) did not apparently change among temperatures.However,in contrast with the primary activity peaks immediately after lights-off at 20 and 25 ℃,the timing of the primary peaks at 10 and 15 ℃ showed a latency of a few hours following lights-off,indicating the inhibiting effect of low temperature on the eels' activity.  相似文献   

盐度对双棘黄姑鱼仔鱼活力及仔稚鱼生长的影响   总被引：8，自引：0，他引：8  

林向阳  刘伟斌  叶金聪 《台湾海峡》2005,24(3):351-355

分别用不同盐度梯度海水对双棘黄姑鱼仔鱼进行饲养试验。结果表明：盐度为17．0．22．0、27．0．31．0～33．0的4个试验组仔鱼的不投饵存活系数分别为5．38、7.35、6.46、6．18；各盐度组仔稚鱼的生长速度没有显著差异（P〉0．05），各组仔鱼经25d的培养，其平均全长为18．8～19．2mm；盐度22．0及27．0的海水中仔稚鱼呈较高的存活率，各盐度组的平均存活率为36、0％、48．5％、46．7％和39．2％．  相似文献   

造山带大陆斜坡沉积类型     

蔡雄飞  蔡海磊  刘德民  陈斌 《海洋地质前沿》2006,22(1):9-13

造山带大陆斜坡可以划分出有扇与无扇大陆斜坡两种沉积类型。有扇大陆斜坡以近源浊积岩、碎屑流为特色;无扇大陆斜坡以远源浊积岩、等深岩、半远洋沉积为特色。因而大陆斜坡也是一个多种沉积作用活跃的场所。造山带深水沉积绝不是常人认为是单一的复理石、千篇一律的重力流,而是内容十分丰富的沉积作用非常活跃和堆积的场所。  相似文献   

Sources and hydrothermal alteration of organic matter in Quaternary sediments: A synthesis of studies from the Central Gulf of California     

Bernd R. T. Simoneit 《Marine and Petroleum Geology》1986,3(4)

Deep sea drilling in the Central Gulf of California, a young and active spreading centre, shows that the high heat flow typical of these regions causes extensive alteration of sediment organic matter, especially near sills and above magma chambers where hydrothermal activity is concentrated. Even on the nearby passive margin, where there are no sills, heat flow is moderately high and hydrocarbon generation has begun in immature sequences. Migrating light hydrocarbons are detected especially where hydrothermal activity is concentrated. Thermogenic methane is more widespread, though not in the passive margin bordering the spreading centre. Despite the incidence of hydrocarbon generation and migration, the amounts of hydrocarbons involved are relatively small and apparently do not lead to commercially significant accumulations of petroleum.The organic matter in these sediments is mostly marine because the Gulf of California generally has low runoff from land and highly productive surface waters. Turbidites rich in terrigenous organic material are locally abundant in the mainly pelagic section in the Guaymas Basin. The highest concentrations of organic matter are found in laminated diatomites deposited on the Guaymas passive margin within the oxygen minimum zone.  相似文献   

大型海藻孔石莼化学组分和生物活性研究新进展     

康凯  王长云  王斌贵  李国强 《海洋湖沼通报》2007,(3):155-159

孔石莼是一种大型绿藻,在食品、药物等领域具有广泛应用。本文综述了近5年来孔石莼化学组分及其生物活性研究进展,并展望了其应用前景。  相似文献   

含硒紫球藻胞外多糖的制备及对体内外肿瘤细胞生长的影响   总被引：4，自引：0，他引：4  

王敏  朱劲华  马宇翔  张成武  李朝军 《海洋科学》2006,30(1):23-27

采用在培养液中添加亚硒酸来实现藻对无机硒的富集和转化,制备一种含硒的紫球藻(Porphyridiumsp.)胞外多糖(Se-PSP);通过DAN荧光法测硒含量及红外光谱,对硒是否结合在多糖上进行了初步探讨;用四唑盐比色法(MTT)研究了不同浓度含硒的紫球藻胞外多糖对3种体外肿瘤细胞生长的影响。通过建立荷瘤小鼠模型,研究了含硒多糖对腹水瘤S180的作用。结果表明含硒的胞外多糖含硒量约为0.015mg/g,40,80mg/LSe-PSP对3种肿瘤细胞SMMC7721、A549、A357均有一定程度的抑制作用,尤其是对SMMC7721抑制程度最为明显。荷瘤小鼠模型实验结果表明100mg/(kg.·d)Se-PSP可以延长荷瘤小鼠的生存时间,Se-PSP有可能成为一种抗肿瘤药物。  相似文献