黄海浮游动物功能群的研究

浮游动物在海洋生态系统物质循环和能量流动中起着至关重要的作用。浮游动物物种组成、生物量和次级生产力的变化会改变生态系统的结构和功能。在黄海生态系统中如何描述这个过程，并使它易于模拟是本论文的研究目的。生物量和生产力是海洋生态系统食物网的基础。谁是浮游动物生物量和次级生产力的基础？哪些种类在生态系统中起关键作用？这些问题在黄海这样的温带陆架边缘海区很难回答，原因是物种组成、生物量和生产力的季节变化显著。因此，在对黄海食物产出的关键过程进行模拟时，需要应用既准确又简便的方法来对浮游动物群落的生态过程进行模拟。在对黄海浮游动物群落结构和物理海洋学特征进行充分的分析之后，浮游动物功能群的方法被确定用来进行黄海生态系统结构和功能的模拟。 根据浮游动物的粒径、摄食习性和营养功能，黄海浮游动物被分为6个功能群：大型浮游甲壳动物功能群（Giant crustacean，GC）、大型桡足类功能群（Large copepods, LC）、小型桡足类功能群（Small copepods，SC）、毛颚类功能群（Chaetognaths）、水母类功能群（Medusae）和海樽类功能群（Salps）。GC、LC和SC是按照粒径大小而划分的功能群，他们是高营养层次的主要食物资源。毛颚类和水母类是两类胶质性的肉食性浮游动物功能群，他们与高营养层次竞争摄食饵料浮游动物；海樽类与其他浮游动物种类竞争摄食浮游植物，而本身的物质和能量却不能有效的传递到高营养层次。本文研究报道了浮游动物各功能群的时空分布、基于浮游动物动能群的黄海生态区划分、饵料浮游动物功能群的生产力、毛颚类对浮游动物的摄食压力以及中华哲水蚤（Calanus sinicus）的摄食生态学。 春季，浮游动物生物量为2.1 g m–2，GC、LC和SC对生物量的贡献率分别为19, 44 和 26%。高生物量的LC和SC功能群主要分布于山东半岛南岸的近岸海域，而GC主要分布在远岸站位。夏季，浮游动物的生物量为3.1 g m–2，GC贡献了73%。GC、LC和SC主要分布在黄海的中部海域。秋季，浮游动物生物量为1.8 g m–2，GC、LC和SC的贡献率相似，分别为36, 33和23%，高生物量的GC和LC分布在黄海中部，而SC主要分布在远岸站位。GC和LC是冬季浮游动物生物量（2.9 g m–2）的优势功能群，分别贡献率了57%和27%，高生物量的GC、LC和SC都分布在黄海的中部海域。与GC、LC和SC相比，毛颚类生物量较低，主要分布于黄海的中北部海域。水母类（本文中指小型水母类）和海樽类斑块分布明显，主要分布于黄海沿岸和北部海域。属于不同功能群的约10个种类为浮游动物的优势种，控制着浮游动物群落的动态。 春季，黄海可以被分成4个浮游动物生态区，浮游动物生物量的分布中心位于山东半岛南岸近岸海域，与第一个生态区相对应，LC和SC在分布中心起主要的控制作用；夏、秋和冬季，黄海分别被分成3、4和3个生态区，浮游动物生物量的分布中心均位于黄海的中部海域，均与各季节的第一个生态区相对应，GC和LC是分布中心生态区的优势功能群，对分布中心起主要的控制作用。黄海冷水团（YSCBW）在GC、LC和SC的空间分布模式中起着重要的作用。黄海不同季节浮游动物生态区的空间分布模式及生态区中起控制作用的优势功能群类别有着重要的生态学意义。 我们将饵料浮游动物功能群细化为0.16–0.25 mm、0.25–0.5 mm、0.5–1 mm、1–2 mm和 >2 mm5个粒径组。应用生物能量学的方法研究了不同粒径浮游动物的生产力。结果表明：浮游动物次级生产力5月份最高，为91.9 mg C m–2 d–1，其次是6月和9月，分别为75.6 mg C m–2 d–1和65.5 mg C m–2 d–1，8月、3月和12月较低，仅为42.3 mg C m–2 d–1、35.9 mg C m–2 d–1和27.9 mg C m–2 d–1。根据这些结果，黄海浮游动物年次级生产力为18.9 g C m–2 year–1。0.16–0.25 mm和 0.25–0.5 mm 两个粒径组对浮游动物次级生产力的贡献率为58–79%，即相对应的SC功能群的周转率（P/B, 0.091–0.193 d–1）要高于GC和LC。 黄海毛颚类功能群的优势种类为强壮箭虫（Sagitta crassa）、纳嘎箭虫（S. nagae）、肥胖箭虫（S. enflata）和百陶箭虫（S. bedoti）。我们对这四种箭虫的生产力和对浮游动物生物量和生产力的摄食压力进行了研究。结果表明：黄海毛颚类总的生物量为98–217 mg m–2，总的生产力为1.22–2.36 mg C m–2 d–1。黄海毛颚类的生物量占浮游动物总生物量的6.35–14.47%，而生产力仅占浮游动物总生产力的2.54–6.04%。强壮箭虫和纳嘎箭虫是黄海毛颚类功能群的绝对优势种，控制着黄海毛颚类群落的动态。黄海毛颚类总的摄食率为4.24–8.18 mg C m–2d–1，对浮游动物现存量和生产力总的摄食压力分别为为0.94%和12.56%。黄海冬季，浮游动物的现存量和生产力为0.4 g C m–2和0.026 g C m–2d–1，而毛颚类的摄食压力却达到了全年的最大值，为1.4%和20.94%。因此，毛颚类的摄食可能对冬季浮游动物群落结构造成重要的影响。通过不同体长组箭虫的摄食率可以推断，黄海毛颚类全年主要摄食小型桡足类，对SC功能群的摄食压力最大。但是在夏季黄海冷水团形成的月份，毛颚类对前体长为2 mm的LC功能群中的种类摄食压力也较大，但此时，由于优势种中华哲水蚤进入滞育阶段，因此毛颚类的摄食会对其种群数量造成严重的影响。 中华哲水蚤在春、秋季的摄食率分别为2.08–11.46和0.26–3.70 µg C female–1 day–1，与微型浮游生物的现存量呈显著的正相关。春季，在黄海的北部，中华哲水蚤通过摄食微型浮游生物吸收的碳量能够满足其代谢和繁殖需求，而在黄海的南部和秋季黄海冷水团锋区附近，中华哲水蚤必须通过摄食其他类型的食物资源来维持其代谢和生殖需求。较低的摄食率、无产卵以及种群中CV期桡足幼体占优势表明，秋季中华哲水蚤在黄海冷水团区域内处于滞育状态。中华哲水蚤优先摄食微型原生动物，并且春季中华哲水蚤总的生长效率（GGE, 3–39%）与食物中微型原生动物的比例呈显著的正相关，表明微型原生动物具有较高的营养价值。但是，因较低的产卵率（0.16–12.6 eggs female–1 day–1）而导致的中华哲水蚤较低的总生长效率（13.4%），可能就是由于其食物中的必需营养成分含量不足（或缺乏）造成的。 本文从生物量的角度，对黄海浮游动物各功能群的时空分布、生态区划分进行了研究报道，对GC、LC和SC功能群的生产力、毛颚类对浮游动物的摄食压力和中华哲水蚤的摄食生态学进行了较为深入的研究，这些结果为黄海食物产出的关键过程的模拟提供了基础资料。今后的研究重点应搞清楚黄海水母类对浮游动物次级生产力的摄食压力和海樽类在食物产出模型中产生的负效应的程度，浮游动物各功能群的组成、季节变化和空间分布模式的长期变化，尤其是在气候变化和人类活动的影响下，将是今后研究的重点。

Ammonia synthesis over Ru/C catalysts with different carbon supports promoted by barium and potassium compounds

Ammonia synthesis over ruthenium catalysts supported on different carbon materials using Ba or K compounds as promoters has been investigated. Ba(NO3)(2), KOH, and KNO3 are used as the promoter or promoter precursor, and activated carbon (AC), activated carbon fiber (ACF). and carbon molecular sieve (CMS) are used as the support. The activity measurement for ammonia synthesis was carried out in a flow micro-reactor under mild conditions: 350-450 degreesC and 3.0 MPa. Results show that KOH promoter was more effective than KNO3. and that Ba(NO3)(2) was the most effective promoter among the three. The roles of promoters can be divided into the electronic modification of ruthenium, the neutralization of surface functional groups on the carbon support and the ruthenium precursor. The catalyst with AC as the support gave the highest ammonia concentration in the effluent among the supports used, while the catalyst with ACF as the support showed the highest turnover-frequency (TOF) value. It seems that the larger particles of Ru on the carbon supports are more active for ammonia synthesis in terms of TOF value. (C) 2001 Elsevier Science B.V. All rights reserved.

Nickel-promoted ligand-free palladium-catalyzed Suzuki coupling reaction

A Ni-promoted ligand-free palladium catalyst system for Suzuki coupling of aryl bromides has been developed in high efficiency under mild reaction conditions. It was obtained in situ by introducing NiCl2 to PdCl2/PVP using a parallel high-throughput screening technique. A wide range of aryl bromides bearing a variety of functional groups was evaluated.

Synthesis and characterisation of novel functional polyolefin containing sulfonic acid groups

The strong polar group, sulfonic acid, has successfully been introduced into ethylene/allylbenzene copolymers without degradation or crosslinking via chlorosulfonation reaction with chlorosulfonic acid as a chlorosulforiating agent in 1, 1,2,2-tetrachloroethane followed by hydrolysis. The degree of sulforiation (DS) can be easily controlled by changing the ratio of chlorosulfonic acid to the pendant phenyls of the copolymer. The microstructure of sulfonated copolymers were unambiguously revealed by H-1 NMR and H-1-H-1 COSY spectral analyses, which indicates that all the sulforiation reactions exclusively took place at the para-position of the aromatic rings.

PENDANT FUNCTIONAL-GROUP COPOLYETHER SULFONES .1. SYNTHESIS AND CHARACTERIZATION OF NEW COPOLYETHER SULFONES WITH PENDANT ALDEHYDE GROUPS MODIFIED INTO PHENOLIC AZOMETHINE GROUPS

New functional copolyether sulfones with pendant aldehyde groups were synthesized by the classical polycondensation reaction between 4,4' -dichlorodiphenyl sulfone (I) and various bisphenols such as 5,5'-methylene bis-salicylaldehyde (II-2), 2,2-bis( 4-hydroxyphenyl)propane (III), and 2,6-bis(4-hydroxybenzylidene)cyclohexanone (IV). Condensation reaction with 4-aminophenol led to pendant phenolic azomethine groups containing copolyether sulfones. The structures of the resulting polymers were confirmed by IR, H-1-NMR spectra, and elemental analyses. The polymers were characterized by reduced viscosity, solubility, thermal stability, DSC, and x-ray diffraction measurements.

Stable Isotope Probing:Linking Functional Activity to Specific Members of Microbial Communities

Linking organisms or groups of organisms to specific functions within natural environments is a fundamental challenge in microbial ecology. Advances in technology for manipulating and analyzing nucleic acids have made it possible to characterize the members of microbial communities without the intervention of laboratory culturing. Results from such studies have shown that the vast majority of soil organisms have never been cultured, highlighting the risks of culture-based approaches in community analysis. The development of culture-independent techniques for following the flow of substrates through microbial communities therefore represents an important advance. These techniques, collectively known as stable isotope probing (SIP), involve introducing a stable isotope-labeled substrate into a microbial community and following the fate of the substrate by extracting diagnostic molecular species such as fatty acids and nucleic acids from the community and determining which specific molecules have incorporated the isotope. The molecules in which the isotope label appears provide identifying information about the organism that incorporated the substrate. Stable isotope probing allows direct observations of substrate assimilation in minimally disturbed communities, and thus represents an exciting new tool for linking microbial identity and function. The use of lipids or nucleic acids as the diagnostic molecule brings different strengths and weaknesses to the experimental approach, and necessitates the use of significantly different instrumentation and analytical techniques. This short review provides an overview of the lipid and nucleic acid approaches, discusses their strengths and weaknesses, gives examples of applications in various settings, and looks at prospects for the future of SIP technology.

Structures and elastic properties of OsN2 investigated via first-principles density functional calculations

The structure, elastic, and electronic properties of OsN2 at various space groups: cubic Fm-3m, Pa-3, and orthorhombic Pnnm were studied by first-principles calculations based on density functional theory. Our calculation indicates that the structure in orthorhombic Pnnm phase is energetically more stable compared with cubic systems. It is metallic, mechanically stable and contains diatomic N-N units with the bond distance 1.418 A. These characters are consistent with experimental facts that OsN2 is orthorhombic and metallic. The calculated bulk modulus 394 GPa is also the highest among the considered space groups, slightly larger than previous value 358 GPa. The calculated elastic anisotropic factors and directional bulk modulus showed that OsN2 possess high elastic anisotropy.

Naphthyl and thionaphthyl end-capped oligothiophenes as organic semiconductors: Effect of chain length and end-capping groups

Two series of oligothiophenes (OThs), NaTn and TNTn (n = 2-6 represents the number of thiophene rings), end-capped with naphthyl and thionaphthyl units have been synthesized by means of Stille coupling. Their thermal properties, optical properties, single crystal structures, and organic field-effect transistor performance have been characterized. All oligomers display great thermal stability and crystallinity. ne crystallographic structures of NaT2, NaT3, TNT2, and TNT3 have been determined. The crystals of NaT2 and NaT3 are monoclinic with space group P2(1)/C, while those of TNT2 and TNT3 are triclinic and orthorhombic with space groups P-1(-) and P2(1)2(1)2(1), respectively. All oligomers adopt the well-known herringbone packing-mode in crystals with packing parameters dependent on the structure of the end-capping units and the number of thiophene rings. The shorter intermolecular distance in NaT3 compared to NaT2 indicates that the intermolecular interaction principally increases with increasing molecular length. X-ray diffraction and atomic force microscopy (AFM) characterization indicate that the NaTn oligomers can form films with better morphology and high molecular order than TNTn oligomers with the same number of thiophene rings. The NaTn oligomers exhibit mobilities that are much higher than those for TNTn oligomers (0.028-0.39 cm(2) V-1 s(-1) versus 0.010-0.055 cm(2) V-1 s(-1), respectively).

Synthesis of novel functional polyolefin containing carboxylic acid via Friedel-Crafts acylation reaction

The strong polar group, carboxylic acid, has triumphantly been introduced into ethylene and allylbenzene copolymers without obvious degradation or crosslinking via Friedel-Crafts (F-C) acylation reaction with glutaric anhydride (GA), succinic anhydride (SA) and phthalic anhydride (PA) in the presence of anhydrous aluminum chloride in carbon disulfide. Some important reaction parameters were examined in order to optimize the acylation process. In the optimum reaction conditions, almost all of the phenyls can be acylated with any anhydride. The microstructure of acylated copolymer was characterized by Fr-IR, H-1 NMR and H-1-H-1 COSY. All the peaks of acylated copolymers can be accurately attributed, which indicates that all the acylation reactions occur only at the para-positions of the substituent of the aromatic rings. The thermal behavior was studied by differential scanning calorimetry (DSC), showing that the melting temperatures (T(m)s) of acylated copolymers with GA firstly decrease slowly and then increase significantly with the increase of the amount of carboxyl acid groups.

Preparation and characterization of post-derivatives from functional polystyrene (ATRP) with p-nitroaniline-azomethine phenol and their thermal and optical study

The functional polystyrene, (Cl-PS)(2)-CHCOOCH2CH2OH ( designated as XPSt and coded P2) was prepared by ATRP at 130(0)C using CuCl and bipyridine as catalysts, 2,2-dichloro acetate-ethylene glycol (DCAG) as multifunctional initiator and THF as solvent. 4-Nitoroaniline azomethine-4' phenol (P1) as chromophores were covalently linked to the functional end groups of the polymer by using simple displacement reaction. The functional polystyrenes, namely XPSt (P2) and (PS)(2)-CHCOOCH2CH2OH, designated as X-PSt and coded P3 and their post-derivatives, namely, DXPSt (P4) and DX-PSt (P5) respectively were characterized by IR, NMR and UV spectroscopies, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), polarising optical microscopy (POM) and XRD studies. DSC showed that incorporation of chromophores in the side chains of polymers towards the polystyrene moiety increases the rigidity of the polymer and subsequently, its glass transition temperature; however the incorporation of side chain towards the alcoholic functional group decreases the glass transition temperature. The post derivatives do not play any significant role to increase the thermal stability ( TGA).

Liquid crystalline and light emitting polyacetylenes: Synthesis and properties of biphenyl-containing poly(1-alkynes) with different functional bridges and spacer lengths

Biphenyl- (Biph-) containing 1-alkynes (3 and 4) and their polymers (1 and 2) with varying bridge groups and spacer lengths were synthesized and the effects of the structural variation on their properties, especially their mesomorphism and photoluminescence behaviors, were studied. The acetylene monomers 3(3) [HCdropC(CH2)(3)O-Biph-OCO(CH2)(10)CH3] and 4(m) [HCdropC(CH2)(m)OCO-Biph-OCO(CH2)(10)-CH3, m = 3, 4] were prepared by sequential etherization and esterification reactions of 1-alkynes. While 3(3) exhibits enantiotropic crystal E and SmB mesophases, its structural cousin 4(3) displays only a monotropic SmB phase. Enantiotropic SmA and SmB mesophases are, however, developed when the spacer length is increased to 4. Polymerizations of the monomers are effected by Mo-, W-, Rh-, and Fe-based catalysts, with the WCl6-Ph4Sn catalyst giving the best results (isolation yield up to 85% and M-w up to 59000). The polymers were characterized by IR, UV, NMR, TGA, DSC, POM, XRD, and PL analyses. Compared to 1(3), 2(3) shows a red-shifted absorption, a higher T-i, and a better packed interdigitated bilayer SmA(d) structure, while the mesophase of 2(4) involves monolayer-packing arrangements of the mesogens. Upon photoexcitation, 1(3) emits almost no light but 2(m) gives a strong ultraviolet emission (lambda(max) similar to 350 nm), whose intensity increases with the spacer length.

Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques

Circular dichroism (CD), fourier transform infrared (FTIR), and fluorescence spectroscopy were used to explore the effect of dimethyl sulfoxide (DMSO) on the structure and function of hemoglobin (Hb). The native tertiary structure was disrupted completely when the concentration of DMSO reached 50% (v/v), which was determined by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for ca. 12 h in a D2O medium no significant change in 1652 cm(-1) band of the FTIR spectrum was produced, which demonstrated that alpha-helical structure predominated. When the concentration of DMSO increased to 57%: (1) the band at 1652 cm(-1) disappeared with the appearance of two new bands located at 1661 and 1648 cm(-1); (2) another new band at 1623 cm(-1) was attributed to the formation of intermolecular beta-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S=O groups in DMSO with C=O groups in amide bonds. Further increasing the DMSO concentration to 80%, the intensity at 1623 cm(-1) increased, and the bands at 1684, 1661 and 1648 cm(-1) shifted to 1688, 1664 and 1644 cm(-1), respectively. These changes showed that the native secondary structure of Hb was last and led to further aggregation and increase of the content of 'free' amide C=O groups. In pure DMSO solvent, the major band at 1664 cm(-1) indicated that almost all of both the intermolecular beta-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. GO-binding experiment suggested that the biological function of Hb was disrupted seriously even if the content of DMSO was 20%. (C) 1998 Elsevier Science B.V. All rights reserved.

Molecular cloning and functional analysis of cathepsin B in nutrient metabolism during larval development in Meretrix meretrix

Seed rearing is an important part in large scale clam culture industry. Since the nutritional history affects early development in bivalve, the condition of larval nutrition plays a key role in successful seed rearing. So far, the molecular mechanism of nutrient uptake in bivalve larvae is unclear. As one of the important proteolytic enzymes, cathepsin B of several organisms has been reported to be involved in digestion. We intended to analyze whether cathepsin B is involved in larval nutrient metabolism in the economic bivalve, clam Meretrix meretrix. The full length of M. meretrix cathepsin B (MmeCB) cDNA was cloned, which is 1647 bp with an open reading frame of 1014 bp. The deduced amino acid sequence encoded a preproenzyme of 337 residues with Cys-114, His-282 and Asn-302 composing cathepsin B activity center. The temporal and spatial expressions of MmeCB mRNA were examined from trochophore to post larva stages by whole mount in situ hybridization. In trochophore stage, no detectable signal was found. In the later three stages, MmeCB mRNA was detected in the digestive gland, suggesting a possible role of MmeCB in digestion. Moreover, MmeCB mRNA was also observed in the epidermal cells in D-veligers. Cathepsin B specific inhibitor (CA074 methyl ester) was applied to block the activity of cathepsin B in unfed larvae. The average shell lengths of treated larvae were smaller than that in control groups. The results of mRNA epidermal distribution and inhibitor treatment in D-veligers indicated that MmeCB may be also associated with other pathway of nutrient metabolism in larval epidermis. The overall results in this paper revealed that MmeCB might play a role in larval nutrient metabolism. (C) 2008 Elsevier B.V. All rights reserved.