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.     

一种中国南海海绵Xestospongia testudinaria中化学成分的研究

综合运用正相和反相硅胶柱层析、Sephadex LH-20凝胶柱层析以及制备HPLC等分离方法,从1种中国南海海绵Xestospongia testudinaria中追踪分离抗肿瘤活性次级代谢产物。从95%乙醇提取物中分离获得8个单体化合物,通过NMR,MS等波谱技术鉴定其结构分别为:E-18,18-二溴-9,17-二烯-5,7-二炔硬脂酸甲酯(1),E-18,18-二溴-9,17-二烯-5,7-二炔硬脂酸乙酯(2),麦角甾-5,7,22-三烯-3-醇(3),麦角甾-4,6,8(14),22-四烯-3-酮(4),胆甾-4-烯-3-酮(5),3-吲哚醛(6),3-吲哚酸(7)和5-吲哚醛(8)。其中,化合物2-5和8为首次从该属海绵中分离得到。化合物1对肿瘤细胞株HCT116和A549显示较强的抑制活性。     

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.     

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。     

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.     

多管藻内生真菌Chaetomium globosum.苯甲醛类次生代谢成分研究

从采自青岛近海的红藻多管藻(Polysiphonia urceolata)中分离到一株毛壳霉属真菌球毛壳菌(Chaetomium globosum.),对其发酵代谢产物的化学成分进行了研究。采用溶剂提取、分配,硅胶柱层析、葡聚糖凝胶柱层析以及制备薄层层析等技术已分离获得6个单体化合物,通过一维、二维超导核磁共振技术、质谱技术等鉴定了其中4个化合物的结构,均为苯甲醛类衍生物,分别为2-(1-庚烯基)-3、6-二羟基-5-(3-甲基-2-丁烯基)苯甲醛(Ⅰ)、2-庚基-3、6-二羟基-5-(3-甲基-2-丁烯基)苯甲醛(Ⅱ)、2-(3、5-庚二烯基)-3、6-二羟基-5-(3-甲基-2-丁烯基)苯甲醛(Ⅲ)、2-(1、3、5-庚三烯基)-3、6-二羟基-5-(3-甲基-2-丁烯基)苯甲醛(Ⅳ)。     

海洋红树林植物卤蕨内生真菌Cladosporium perangustum MA-318中一个新的链烯酸酐衍生物methylate cordyanhydride A

从采自海南东寨港的红树林卤蕨(Acrostichum aureum Linn.)中分离得到的一株内生真菌Cladosporium perangustum MA-318,对其次级代谢产物进行了研究。利用反相硅胶柱层析、正相硅胶柱层析以及葡聚糖凝胶Sephadex LH-20柱层析等分离手段获得一个单体化合物。通过波谱数据分析(HRESIMS、1D NMR、2D NMR)鉴定该化合物为新的链烯酸酐,其结构为methyl(E)-3-(4-(2-((4-(but-1-en-1-yl)-2,5-dioxo-2,5-dihydrofuran-3-yl)methyl)butyl)-2,5-dioxo-2,5-dihydrofuran-3-yl)propanoate,命名为methylate cordyanhydride A。抗菌实验表明该化合物对藤黄微球菌(Micrococcus luteus)表现出一定的抑制作用。     

鼠尾藻的化学成分研究

利用正相硅胶柱层析、反相硅胶柱层析、凝胶Sephadex LH-20柱层析、制备薄层层析(PTLC)及重结晶等分离手段,从鼠尾藻(Sargassum thunbergii)中分离得到8个化合物,通过MS、1D和2D NMR等波谱技术鉴定结构为:黑麦草内酯(1);Hexahydro-3a,6-dihydroxy-4,4,7a-trimethyl-2(3H)-benzofuranone(2);5-甲酯基-5-羟基-3-甲氧基-2-环戊烯-1-酮(3);顺-1,6,9,12,15,18-二十一碳六烯酸(4);顺-5,8,11,14-二十碳四烯酸(5);顺-5,8,11,14,17-二十碳五烯酸甲酯(6);植醇(7)和岩藻甾醇(8).这些化合物均为首次从该海藻中分离获得.     

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.     

中国南海圆裂短足软珊瑚的甾体成分研究

从南海圆裂短足软珊瑚(Cladiella krempfi)中分离出12个甾体化合物,分别鉴定为:1,2-[1',3',4']oxodithiin-pregna-20-en-3-one(1);19-nor-4-methylpregna-1,3,5(10),20-tetraen-1-ol(2);pregna-1-en-3-one-20-ol(3);pregna-1,7-dien-20-ol-3-one(4);pregna-5,20-dien-3-O-α-fucopyranoside(5);pregna-20-en-3-O-α-fu-copyranoiside(6);孕甾-1,20-二烯-3-酮(7);孕甾-1,4,20-三烯-3-酮(8);24-甲基-5α-胆甾-7,22-二烯-3β,5,6β-三醇(9);26-甲基-24-亚甲基胆甾-5烯-3β-醇(10);胆甾-5-烯-3β醇(11);β-谷甾醇(12).化合物1～6系首次从Cladiella属软珊瑚中获得的孕甾类化合物.对所获得化合物的生源途径进行了初步讨论.     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

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。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.