13 resultados para Acartia sp., c5, mass

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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In the present study, one- and two-dimensional gel electrophoresis combined with high resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) have been applied as powerful approaches for the proteome analysis of surfactant proteins SP-A and SP-D, including identification of structurally modified and truncation forms, in bronchoalveolar lavage fluid from patients with cystic fibrosis, chronic bronchitis and pulmonary alveolar proteinosis. Highly sensitive micro preparation techniques were developed for matrix-assisted laser desorption/ionization (MALDI) FT-ICR MS analysis which provided the identification of surfactant proteins at very low levels. Owing to the high resolution, FT-ICR MS was found to provide substantial advantages for the structural identification of surfactant proteins from complex biological matrices with high mass determination accuracy. Several protein bands corresponding to SP-A and SP-D were identified by MALDI-FT-ICR MS after electrophoretic separation by one- and two-dimensional gel electrophoresis, and provided the identification of structural modifications (hydroxy-proline) and degradation products.

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Nannochloropsis sp. was grown with different levels of nitrate, phosphate, salinity and temperature with CO2 at 2,800 mu l l(-1). Increased levels of NaNO3 and KH2PO4 raised protein and polyunsaturated fatty acids (PUFAs) contents but decreased carbohydrate, total lipid and total fatty acids (TFA) contents. Nannochloropsis sp. grew well at salinities from 22 to 49 g l(-1), and lowering salinity enhanced TFA and PUFAs contents. TFA contents increased with the increasing temperature but PUFAs contents decreased. The highest eicosapentaenoic acid (EPA, 20:5 omega 3) content based on the dry mass was above 3% under low N (150 mu M NaNO3) or high N (3000 mu M NaNO3) condition. Excessive nitrate, low salinity and temperature are thus favorable factors for improving EPA yields in Nannochloropsis sp.

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We deduce the eight-band effective-mass Hamiltonian model for a manganese-doped ZnSe quantum sphere in the presence of the magnetic field, including the interaction between the conduction and valence bands, the spin-orbit coupling within the valence bands, the intrinsic spin Zeeman splitting, and the sp-d exchange interaction between the carriers and magnetic ion in the mean-field approximation. The size dependence of the electron and hole energy levels as well as the giant Zeeman splitting energies are studied theoretically. We find that the hole giant Zeeman splitting energies decrease with the increasing radius, smaller than that in the bulk material, and are different for different J(z) states, which are caused by the quantum confinement effect. Because the quantum sphere restrains the excited Landau states and exciton states, in the experiments we can observe directly the Zeeman splitting of basic states. At low magnetic field, the total Zeeman splitting energy increases linearly with the increasing magnetic field and saturates at modest field which is in agreement with recent experimental results. Comparing to the undoped case, the Zeeman splitting energy is 445 times larger which provides us with wide freedom to tailor the electronic structure of DMS nanocrystals for technological applications.

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Methomyl, an extremely toxic pesticide, is widely used in agriculture. A strain named mdw-1 capable of degrading methomyl rapidly was successfully isolated from activated sludge in this study. It could utilize methomyl as the sole carbon or nitrogen source. The optimal temperature and medium pH for its growth and methomyl biodegradation were 30 degrees C and 7.0, respectively. It was identified as a Paracoccus sp. according to its morphological features, physiological and biochemical characteristics, and phylogenetic analysis based on the sequence of 16S rDNA. Gas chromatography-mass spectrometry (GC-MS) analysis showed that methomyl could be completely transformed to S-methyl-N-hydroxythioacetamidate in 10 h of incubation with the isolate mdw-1.

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To study the biotransformation of arctigenin, arctigenin was anaerobically incubated with Eubacterium sp. ARC-2 of human intestinal bacteria in vitro. Arctigenin formed a molecular ion [M-H](-) in negative ion mode. The arctigenin and its metabolites were investigated directly by the electrospray ionization tandem mass spectrometry ion trap and Fourier transform ion cyclotron resonance. Arctigenin was transformed to 4',4 ''-dihydroxylenterolactone by E sp. ARC-2 through 3 types of demethylation products.

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High-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry was developed and applied to the proteome analysis of bronchoalveolar lavage fluid (BALF) from a patient with pulmonary alveolar proteinosis. With use of 1-D and 2-D gel electrophoresis, surfactant protein A (SP-A) and other surfactant-related lung alveolar proteins were efficiently separated and identified by matrix-assisted laser desorption/ionization FTICR mass spectrometry . Low molecular mass BALF proteins were separated using a gradient 2-D gel. An efficient extraction/precipitation system was developed and used for the enrichment of surfactant proteins. The result of the BALF proteome analysis show the presence of several isoforms of SP-A, in which an N-non-glycosylierte form and several proline hydroxylations were identified. Furthermore, a number of protein spots were found to contain a mixture of proteins unresolved by 2-D gel electrophoresis, illustrating the feasibility of high-resolution mass spectrometry to provide identifications of proteins that remain unseparated in 2-D gels even upon extended pH gradients.

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In the present paper a study of C-19-diterpene type of aconitum alkaloids, extracted from aconite roots in Aconitum carmichaeli Debx has been made using matrix-assisted laser desorption/ionization time of Eight mass spectrometry (MALDI-TOFMS), The results demonstrated that the aconitum alkaloids from aconite roots can be determined simultaneously by this method, which was found to be superior to other analytical methods with regard to speed and sensitivity. Fourteen known aconitum alkaloids, including aconitines, benzoylaconitines and lipoaconitines, were assigned in the methanol extract and three compounds not reported before have been targeted separation. The evaluation of the efficiency of different extractions has been studied. These results suggested that the differences of the polarity and basicity of aconitine, and benzoylaconitines and lipoaconitines result from the C-8 constituent groups that are easily lost under MALDI, (C) 1998 John Wiley & Sons, Ltd.

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Using electrospray ionization mass spectrometry (MS) combined with sequential tandem MS(ESI-MSn), two major steroidal saponins extracted from Tribulus terrestris were studied, and considerable useful structural information was obtained. The structure of the proposed known steroidal saponin was verified, and the structure of the unknown saponin was investigated using MSn experiments. Some special fragment ions were also observed, and the corresponding fragmentation mechanisms were investigated which are characteristic for steroidal saponins and can give some information on the linkage position of some sugar groups in saponins. This methodology has been established as a powerful tool for the rapid, comparative analysis of mixtures such as crude plant extracts. (C) 1998 John Wiley & Sons, Ltd.

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Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) of oligosaccharides and polysaccharides has been investigated in detail, It is demonstrated that cationized species of oligosaccharides, [M+Na](+) and [M+K](+), are dominant products under the MALDI condition, and negative ions of oligosaccharides are not formed to any significant extent in this process, The molecular masses of polysaccharides are similarly determined by positive- and negative-ion MALDI-MS with the help of column chromatography. The distinction between positive- and negative-ion MALDI mass spectra of oligo-and polysaccharides indicates that the MALDI processes for saccharides vary with molecular mass. The matrix plays a more important role in the ionization process for oligosaccharides, while in the desorption process for polysaccharides. (C) 1998 John Wiley & Sons, Ltd.

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A successful analysis of silver was reported utilizing laser desorption/ionization time-of-flight mass spectrometry (LDI/TOF-MS) in this paper, The silver cluster ions Ag-n(+) and AgnO+ (n=2 similar to 5) were formed during laser desorption/ionization. In the presence of I-, K+ and Na+, the peaks corresponding, to the cluster ions [AgnIn-1](+) (n=2 similar to 6) and the adduct ions [AgI](+), [AgI]Na+ and [AgI]K+ were observed in the positive ion spectrum; the peaks corresponding to [AgnIn+1](-) (n=1 similar to 3) were found in the negative ion spectrum, all of which accompanied by sliver isotope distribution, The formation of silver cluster ions was accomplished through two-stage reaction: the first step was the generation of clusters, which was followed by the processes of photoionization and ion/molecule reaction.

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In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1 D and 2 D NMR spectra.

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A simple, low-cost, and efficient airlift photobioreactor for microalgal mass culture was designed and developed. The reactor was made of Plexiglas, and composed of three major parts: outer tube, draft tube and air duct. The fluid-dynamic characteristics of the airlift reactor were studied. The system proved to be well suited to the mass cultivation of a marine microalga, Chlorella sp. In batch culture, the biomass volumetric output rate of 0.21 g l(-1) d(-1) was obtained at the superficial gas velocity of 4 mm s(-1) in the draft tube.

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20世纪90年代以来,为了确保日益增长的人口对蛋白质的需求,海洋鱼类养殖在全球范围内日趋发展。然而,许多养殖鱼类的品质如抗病力、口味等与野生种类相比大为降低。饵料对于鱼类品质的好坏起着至关重要的作用。在海洋的自然环境中,浮游动物,特别是数量庞大、种类繁多的桡足类是野生鱼类的天然活饵料。哪些桡足类适于作养殖饵料,如何获得、从何处获得桡足类,人工培养是否可行,能否通过加入桡足类来改善养殖鱼类的品质是长期以来业内人士一直关注的问题,需要大量的基础性探索研究工作。 开展有潜在开发价值种的生物学特性及室内培养的基础研究,进而开展大量生产技术的研究与应用,不仅是开发利用桡足类的一个重要途径,而且可以获得一些重要的生态学参数。 本论文自2003年10月-2004年9月之间,在胶州湾采集不同的桡足类种类,通过室内比较培养实验,选定双刺纺锤水蚤作为具有开发潜力的研究培养对象,对其展开一系列培养条件及生物学特性研究,在此基础上进行了小水体增殖培养,结合现场调查资料对与其生活策略相关的生态学问题进行了初步研究探索。结果如下: 筛选:2003年10月-2004年9月全年不同季节共采集11 种桡足类,在室内自然温度、自然海水(盐度30-32)下长时间培养,粗略筛选出能够经受实验室人工养殖水体生活的种类有:强额拟哲水蚤(Paracalanus. crassirostris)、汤氏长足水蚤(Calanopia thompson)、太平洋真宽水蚤(Eurytemora pacifica)、双刺纺锤水蚤(Acartia bifilosa)。对上述种类的成体和子代幼体分别测定其对不同盐度、温度的耐受能力。培养结果表明:18℃室温下,强额拟哲水蚤幼体在盐度20以上的环境中,存活时间不超过11天;汤氏长足水蚤雌体在培养温度低于20℃时,只能存活10天;25℃室温下,当盐度低于20时,汤氏长足水蚤雌体存活时间不超过9天,子代的存活时间不超过7天;太平洋真宽水蚤不适宜在温度较高的夏秋季培养,幼体在不同盐度的实验条件下存活时间不超过5天,不适宜长期培养;双刺纺锤水蚤在全年8-24℃的室内培养温度范围内保持了24-85%的存活率,雌体和子代在盐度10-35的范围内都能存活,最终结果表明双刺纺锤水蚤是其中最适宜进行人工培养的种类。 繁殖:对双刺纺锤水蚤雌体的培养条件和繁殖生物学的研究结果表明:在本实验所使用的6种微藻饵料:微绿球藻(Nannochloropsis oculata)、小球藻(Chlorella.sp)、等鞭金藻(Isochrysis galbana)、三角褐指藻(Phaeodactylum tricornutum)、亚心型扁藻(Platymonas subordiformis)、中肋骨条藻(Skeletonema costatum)中,亚心型扁藻和中肋骨条藻适宜成体培养,亚心型扁藻对雌体存活有利,排粪率也要比中肋骨条藻低得多,亚心型扁藻在高温条件下的饵料利用效率要高于中肋骨条藻,中肋骨条藻对产卵有利,二者混合优势互补;预饥饿处理的双刺纺锤水蚤恢复到最高产卵率需要较长的时间,并且一直保持较低的产卵率;该种繁殖的最适温度范围15-20℃;在10-25℃温度范围内的平均产卵率差异并不显著。 生长及发育:对双刺纺锤水蚤幼体培养条件及发育生物学研究结果表明:在本实验所使用的6种微藻饵料中,微绿球藻是比较理想的开口饵料;粒径小( 4 m)的微藻——微绿球藻和小球藻不能保证双刺纺锤水蚤后期无节幼体发育至桡足阶段,22℃以下采用微绿球藻 + 亚心型扁藻 + 中肋骨条藻的食物搭配,22℃以上需加入粒径在4m左右的等鞭金藻。 世代时间:通过一系列的温度梯度实验,证明在相同饵料的情况下,温度对双刺纺锤水蚤的发育具有显著的影响,在15-25℃的范围内,随着温度的升高,生长速度加快、世代周期缩短;在温度条件为15、18、20、22、25℃下的世代时间分别为25.5, 18.5, 13, 11.5, 9.5天。 群体培养:研究了适宜的微藻饵料种类搭配比例以及总饵料浓度对种群日均增值率的影响。结果表明:20℃下培养宜采用亚心型扁藻:中肋骨条藻:微绿球藻按含碳量2:1:1的比例组成混合饵料,达到最高增殖率的混合饵料浓度范围在1.0-4.0 μg C ml-1之间;25℃下培养宜采用亚心型扁藻:中肋骨条藻:微绿球藻:等鞭金藻按含碳量2:1:1:2的比例组成混合饵料,日均增殖率在混合饵料总浓度为1.0 μg C ml-1 时最高,低于和高于此浓度都会降低日增值率。 度夏机制:针对野外大面调查发现双刺纺锤水蚤在高温季节的胶州湾内仍然存在的事实(传统观点认为该种在夏季从水体中消失,通过休眠卵度夏),本论文从基础生态学研究出发,根据胶州湾夏季的温度和叶绿素浓度资料,设计实验研究了高温和饵料浓度对成体繁殖和幼体生长发育的影响。实验发现,饵料浓度对高温下雌体的繁殖有着明显的影响,15g Chla l-1浓度下的雌体在28℃都可以保持产卵状态,而且卵的孵化率也在50%以上;各处理中的卵都很快孵化,并保持了60%以上的孵化率;高浓度组15 g Chla l-1和10 g Chla l-1,无节幼体都能发育至成体,低浓度5 g Chla l-1处理组中,28℃下,不能发育至桡足阶段,而25℃下也只能发育至C4期。在本实验中没有发现双刺纺锤水蚤产生休眠卵。在胶州湾自然环境中发现该种全年存在。胶州湾中的双刺纺锤水蚤在夏季能够在不产生休眠卵的情况下安全度夏。