一种中国南海枝网刺柳珊瑚次级代谢产物研究

利用硅胶、凝胶Sephadex LH-20、反相硅胶ODS柱色谱和HPLC等手段对一种中国南海枝网刺柳珊瑚Echino-gorgia sassapo reticulata(Esper)的次级代谢产物进行了研究。从提取物的乙酸乙酯相中分离获得13个单体化合物,运用现代波谱技术并结合文献数据,鉴定其结构分别为:尿嘧啶核糖核苷(1),2’-脱氧尿嘧啶核苷(2),2’-脱氧胸腺嘧啶核苷(3),尿嘧啶(4),鲨肝醇(5),1-O-eicosanylglycerol(6),11,13-dihydro-7,11-dehydro-3-desoxy-zaluzalanin C(7),邻苯二甲酸二丁酯(8),邻苯二甲酸1-(2-甲基-丁基)酯-2-丁酯(9),(22E)-5-αcholest-22-ene-3α,5α,6-βtriol(10),(22E,24S)-24-methyl-5-αcholesta-7,22-diene-3β,5α,6,β9-tetraol(11),(24S)-methylene cholestane-3β,5α,6,β18-tetrol(12),胆甾醇(13)。除了化合物3和13外,其他化合物均为首次从该属柳珊瑚中分离得到。另外化合物9为首次作为天然产物单体化合物分离得到,化合物12为首次从柳珊瑚中获得。对化合物1 3进行了卤虫致死活性及斑马鱼胚胎毒性测试。     

一株海绵共附生真菌Pleosporaceae sp.中甾体类化合物及其生物活性

在生物活性测定指导下,综合运用硅胶柱层析、凝胶柱层析以及半制备HPLC等方法,从南海海绵Xestospongiatestudinaria来源的一株共附生真菌Pleosporaceae sp.发酵液的乙酸乙酯提取物中分离鉴定出5个甾体类化物,通过NMR,MS等波谱技术鉴定其结构分别为:(22E,24R)-5α,8α-epidioxy-ergosta-6,22-dien-3β-ol(1),(22E,24R)-5α,8α-epidioxy-ergosta-6,9,22-trien-3β-ol(2),(22E)-ergosta-5,7,22-trien-3β-ol(3),ergosta-6α-hydroxy-4,22-dien-3-one(4),(22E)-5α-cholesta-7,22-diene-3β,5α,6β-triol(5)。这些化合物均为首次从Pleosporaceae属真菌中分离获得。化合物1,4和5具有较强的卤虫Ar-temia salina致死活性,化合物1还显示强的抗藤壶Balanus amphitrite附着活性,其EC50为0.85μg/mL。     

海洋红树林植物黄槿内生真菌Aspergillus sydowii EN-198化学成分研究

对采自海南东寨港的海洋红树林植物黄瑾(Hibiscus tiliaceus)叶中分离到的一株内生真菌Aspergillus sydowii EN-198的次生代谢产物进行了研究.利用正相与反相硅胶柱层析、葡聚糖凝胶Sephadex LH-20柱层析以及制备薄层层析(PTLC)等分离手段从其发酵液中分离得到14个化合物,通过一维、二维核磁共振技术、质谱技术等鉴定了所有化合物的结构,分别为:环-(S-脯氨酸-S-苯丙氨酸)(1),环-(S-脯氨酸-S-亮氨酸)(2),环-(S-苯丙氨酸-S-色氨酸)(3),(1S)-1-(4 '-间羟基苯甲酸)-1,1,5,5-二甲基己二醇(4),曲酸(5),N-[2-(4-吲哚)乙基]乙酰胺(6),N-[2-(4-对羟基苯酚)乙基]乙酰胺(7),胸腺嘧啶脱氧核苷(8),尿嘧啶脱氧核苷(9),尿嘧啶核苷(10),过氧化麦角甾醇(11),麦角甾醇(12),(2S,2'R,3R,3 'E,4E,8E)-N-(2’-羟基-3’-十六烯酰基)-9-甲基-4,8-二十碳二烯-1,3-二醇(13)以及1-O-β-D-葡萄糖基-(2S,2'R,3R,3'E,4E,8E)-N-(2’-羟基-3’-十六烯酰基)-9-甲基-4,8-二十碳二烯-1,3-二醇(14);其中化合物1和2为首次从Aspergillus sydowii中分离得到.对所有化合物测试其抑菌活性,发现化合物5与7对金黄色葡萄球菌有较好抑制活性.     

海洋红藻多管藻内生真菌EN-22 的化学成分研究

对采自广西涠州岛近海多管藻(Poiysiphonia urceolata)分离到的一株内生真菌EN-22的次生代谢产物的化学成分进行了研究.利用正相硅胶柱层析、葡聚糖凝胶Sephadex LH-20柱层析、制备薄层层析(PTLC)以及重结晶等分离手段从该菌发酵液中分离得到15个化合物,通过一维、二维核磁共振技术、质谱技术等鉴定了所有化合物的结构,分别为:4-(4-喹啉)-4-羟基-2-丁酮(1),3-羟基-3-(2-氧丙基)吲哚-2-酮(2),3-吲哚乙醇(3),3-吲哚甲酸(4),2-羟基-3-吲哚丙酸(5),2-酮-3-吲哚乙醇(6),3,3-二吲哚-2-羟基-丙醇(7),β-咔啉(8),尿嘧啶(9),环-(S-脯氨酸-S-异亮氨酸)(10),(22E,24R)-3β,5α,9α-三羟基麦角甾-7,22-二烯-6-酮(11),(22E,24R)-5α,6α-环氧麦角甾-8,22-二烯-3β,7α-二醇(12),5α,6α-环氧-24(R)-甲基胆甾-7,22-二烯-3β-醇(13),胡萝卜苷(14),过氧化麦角甾醇(15);其中化合物1和2为新天然产物,并首次报道化合物1的碳谱数据.     

海鞘内生真菌焦曲霉Aspergillus ustus TK-5的化学成分研究

焦曲霉(Aspergillusustus)TK-5是分离自土耳其海域海鞘(Pyuramomus)新鲜组织中的一株内生真菌,利用正相与反相硅胶柱层析、葡聚糖凝胶Sephadex LH-20柱层析以及高效液相制备等色谱方法从其发酵产物中分离得到17个化合物,通过一维、二维核磁共振、质谱等技术鉴定了所有化合物的结构,分别为血苋烷型倍半萜类化合物strobilactone A(1), ustusolate E(2), ustusolate C(3), ustusolate D(4),11-hydroustusolate E(5), 11, 6’-hydroustusolate E(6),(2’E, 4’E, 6’E)-6-(1’-carboxyocta-2’, 4’, 6’-triene)-11,12-epoxy-9, 11-dihydroxydrim-7-ene(7), 12-hydroxy-6-epi-albrassitriol (8), ustusolate A (9), deoxyuvidin B(10)和二倍半萜类化合物6-epi-ophiobolinG(11),(6α)-21,21-O-dihydroophiobolinG(12),6-epi-ophiobolin K(13), ophiobolin P(14) ophiobolin H(15), ophiobolin Q(16)及ophiobolin R(17)。活性筛选表明化合物2、6、7、9、11和13对神经氨酸酶具有一定的抑制活性,其半数抑制浓度(IC50)分别为31.8、37.3、28.4、36.8、46.6和37.6μmol/L。     

红树林植物木榄根际土壤真菌Penicillium sp. MA-37 的化学成分研究

对采自海南文昌红树林根际土壤样品中分离到的真菌Penicillium sp. MA-37的次生代谢产物的化学成分进行了研究.利用硅胶柱层析、葡聚糖凝胶Sephadex LH-20柱层析、制备薄层层析以及重结晶等分离方法并通过现代波谱技术共分离、鉴定了8个天然产物,分别为:氮-(2-甲氧基-4-羟基苯)-丙酰胺酸(1),氮-(2,4-二甲氧基苯)-丙酰胺酸(2),氮-(2,4-二甲氧基苯)-丙酰胺酸甲酯(3),(22E,24R)-麦角甾-5,7,22-三烯-3β-醇(4),(22E,24R)-麦角甾-4,6,8(14),22-四烯-3-酮(5),(22E,24R)-5α,8α-环二氧麦角甾-6,22-双烯-3β-醇(6), asperamide B (7), cis-4-hydroxy-6-deoxyscytalone (8);其中化合物1为新化合物,化合物2和3为新天然产物.     

海洋褐藻叉开网翼藻中的单萜成分研究

为了研究中国沿海海藻中的活性化学成分, 利用正相硅胶柱色谱、Sephadex LH-20 柱色谱、反相HPLC 及重结晶等手段, 从采自青岛的褐藻叉开网翼藻(Dictyopteris divaricata Okam.)中首次分离得到了6 个单萜类化合物, 经红外波谱(IR), 质谱(MS)及核磁共振波谱(¹H NMR、¹³C NMR)等现代波谱技术鉴定为loliolide (1), isololiolide (2), 3β-hydroxy-5α,6α-epoxy-7-megastigmen-9-one (3), dehydrovomifoliol(4), (3R)-4-[(2R,4S)-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-oneiol (5), (3R)-4-[(2R,4S)-4-acetoxy-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-one (6)。并通过MTT 法对所得化合物进行细胞毒活性筛选, 通过比色法进行乙酰胆碱酯酶抑制活性筛选。     

滨海湿地耐盐植物二色补血草化学成分研究

采用硅胶柱层析,Sephedex-LH-20凝胶层析,HPLC等方法,从滨海湿地耐盐植物二色补血草中分离得到了10个单体化合物。运用NMR,MS以及与文献对照,鉴定它们的结构分别为豆甾烷-3,6-二酮(1),豆甾-4烯-3,6-二酮(2),6β-羟基-豆甾-4-烯-3-酮(3),5α,8α-环二氧-24-甲基-胆-甾6,22E-二烯-3β-醇(4),5,α8α-环二氧-24-甲基-胆甾-6,9,22E-三烯-3β-醇(5),麦角-甾4,6,8(14),22E?四烯-3-酮(6),植醇(7),正十六烷酸(8),亚油酸(9),亚油酸单甘油酯(10)。化合物1~7和10为首次从该植物中分离得到。     

中国南海短指软珊瑚中化学成分的研究

运用硅胶柱层析、Sephadex LH-20凝胶柱层析和HPLC等技术,采用活性追踪分离的方法,对南海短指软珊瑚Sinularia sp.的化学成分进行了研究.从乙醇提取物中分离获得单体化合物,运用NMR,MS等波谱技术鉴定了8个化合物的结构,分别为:3β-羟基-24-亚甲基胆甾-5-烯-7-酮(1),孕甾烯醇酮(2),cembrene A(3),epoxycembrane A(4),4,8,12-trimethyl-1-(1-methylethenyl)-3,7-cyclotetradecadien-10-one(5),(3E,7E,11E)-11,12-dihydroxy-1-isopropyl-4,8,12-trimethyicyclotetradeca-1,3,7-triene(6),邻苯二甲酸二丁酯(7)和十九烷-2-酮(8).化合物5和8为首次从珊瑚动物中分离得到,6为首次从短指软珊瑚属中分离得到.化合物3和4显示较强的卤虫致死活性.西松烷二萜类化合物是该短指软珊瑚中的重要活性成分.     

多指软珊瑚Sinularia numerosa中的倍半萜类化学成分

利用硅胶柱层析和葡聚糖凝胶柱层析等技术对多指软珊瑚(Sinularia numerosa)的丙酮提取物进行分离纯化,得到7个倍半萜类化合物,根据现代波谱技术(NMR、MS等)以及与文献对比,它们分别被鉴定为10α-hydroxy-⊿9(15)-africanene(1),⊿9(15)-africanene(2),(9R)-africanane-9,15-diol(3),(9S)-africanane-9,15-diol(4),eudesm-4(15)-ene-1β,6α-diol(5),octahydro-4-hydroxy-3α-methyl-7-methylene-α-(1-methylethyl)-1H-indene-1-methanol(6)和guaianediol(7)。这些化合物均为首次从多指软珊瑚中分离得到。     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.     

A Tidal Flow Model for the Gulf of Kachchh, India

A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage.