EFFECT OF ELEVATED BICARBONATE CONCENTRATION ON GROWTH, CHLOROPHYLL A FLUORESCENCE AND ULTRA-STRUCTURE OF Microcystis aeruginosa (CYANOBACTERIUM)

The influence of bicarbonate (HCO3-) on Microcystis aeruginosa FACHB 905 was assessed in this study. Growth curves, chlorophyll a fluorescence and ultrastructure were measured at two HCO3- concentrations, 2.3 mM and 12.4 mM. A treatment of sodium chloride (NaCl) was also conducted alongside to establish the influence level of sodium. It was found that upon treatment with elevated HCO3- concentrations of 2.3 mM and 12.4 mM, cell densities were 13% and 27% (respectively) higher than controls. In photosynthetic performance, elevated HCO3- concentration initially stimulated Fv/Fm at the prophase of culture and then subsequently inhibited it. The inhibition of 2.3mM was higher than that of 12.4mM HCO3-. The maximum relative electron transport rate (ETRmax) exhibited inhibition at elevated HCO3- concentrations. DI0/CS was decreased at 2.3 mM and increased at 12.4mM. In the case of both treatments. ABS/CSI TR0/CS, ET0/CS, RC/CS0 and RC/CSm were decreased by elevated HCO3- concentrations, which indicated damage to photosynthetic apparati and an inactivation of a fraction of reaction centers. This point was also proven by ultrastructural photos. High HCO3--exposed cells lost the characteristic photosynthetic membrane arrangement compared with the control and high salinity treated samples. At the 2.3mM concentration of HCO3-. damage to photosynthetic apparati caused decreased photosynthetic activity. These findings suggested that elevated HCO3- concentration stimulated the growth and photosynthesis of M. aeruginosa FACHB 905 in a short time. Exposure to high HCO3- concentrations for a longer period of time will damage photosynthetic apparatus. In addition, the ultrastructure indicated that elevated HCO3--concentration lead to photosynthetic apparati damage. In our experiment, it was observed that the inhibition effect of 2.3mM HCO3- was higher than that of 12.4mM HCO3-. We hypothesized that M. aeruginosa FACHB 905 induced a protective mechanism under high concentrations of HCO3-.

Constitutive expression of thymidylate synthase from LCDV-C induces a transformed phenotype in fish cells

Thymidylate synthase (TS), an essential enzyme in DNA synthesis and repair, plays a key role in the events of cell cycle regulation and tumor formation. Here, an investigation was presented about subcellular location and biological function of viral TS from lymphocystis disease virus from China (LCDV-C) in fish cells. Fluorescence microscopy revealed that LCDV-C TS was predominantly localized in the cytoplasm in fish cells. Cell cycle analysis demonstrated that LCDV-C TS promoted cell cycle progression into S and G2/M phase in the constitutive expressed cells. As a result, the cells have a faster growth rate compared with the control cells as revealed by cell growth curves. For foci assay, the TS-expressed cells gave rise to foci 4-5 weeks after incubation. Microscopic examination of the TS-induced foci revealed multilayered growth and crisscross morphology characteristic of transformed cells. Moreover, LCDV-C TS predisposed the transfected cells to acquire an anchorage-independent phenotype and could grow in 0.3% soft agar. So the data reveal LCDV-C TS is sufficient to induce a transformed phenotype in fish cells in vitro and exhibits its potential ability in cell transformation. To our knowledge, it is the first report on viral TS sequences associated with transforming activity. (C) 2007 Elsevier Inc. All rights reserved.

Cloning of biologically active genomes from a Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus isolate by using a bacterial artificial chromosome

Purification of genotypes from baculovirus isolates provides understanding of the diversity of baculoviruses and may lead to the development of better pesticides. Here, we report the cloning of different genotypes from an isolate of Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) by using a bacterial artificial chromosome (BAC). A transfer vector (pHZB10) was constructed which contained an Escherichia coli mini-F replicon cassette within the upstream and downstream arms of HaSNPV polyhedrin gene. Hz2e5 cells were co-transfected with wild-type HaSNPV DNA and pHZB10 to generate recombinant viruses by homologous recombination. The DNA of budded viruses (BVs) was used to transform E. coli. One of the bacmid colonies, HaBacHZ8, has restriction enzyme digestion profiles similar to an in vivo cloned strain HaSNPV-G4, the genome of which has been completely sequenced. For testing the oral infectivity, the polyhedrin gene of HaSNPV was reintroduced into HaBacHZ8 to generate the recombinant bacmid HaBacDF6. The results of one-step growth curves, electron microscopic examination, protein expression analysis and bioassays indicated that HaBacDF6 replicated as well as HaSNPV-G4 in vitro and in vivo. The biologically functional HaSNPV bacmids obtained in this research will facilitate future studies on the function genomics and genetic modification of HaSNPV. (C) 2003 Elsevier B.V. All rights reserved.

New color centers and photostimulated luminescence of BaFCl : Eu2+

Three new absorption bands, appearing around 670, 865 and 980 nm, are observed in BaFCl:Eu2+ phosphors. They are ascribed to F aggregates formed by association of F centers or by trapping of electrons to the primary F-n(+) (n = 2,3,4) centers. The growth curves of F and F-aggregated centers are similar and may be divided into three stages. The photostimulated luminescence (PSL) decays by stimulation into the absorption bands of F centers and of F aggregates are different; the former decay logarithmically and the latter decay hyperbolically. Some non-radiative processes related to F aggregates, such as electron migration, occur accompanying the PSL process, which may reduce the PSL efficiency and sensitivity of the phosphors. (C) 1997 Published by Elsevier Science Ltd. All rights reserved.

低极性化合物的电喷雾质谱检测方法及几种中藏药材的活性成分研究

本学位论文首先报道了为解决低极性化合物的电喷雾质谱（ESI-MS）分析难题而建立的一种衍生化分析方法；然后从色谱-质谱联用分析、分离纯化和结构鉴定等方面分别报道了几种中藏药材的活性成分研究。论文由下述六章组成： 第一章报道了盐酸羟胺衍生化方法在电喷雾质谱 (ESI-MS) 分析中的应用。该方法利用盐酸羟胺和羰基成肟的快速反应，建立了针对三萜酮等含酮或醛羰基低极性化合物的ESI-MS 信号增强技术。此方法不仅可应用于增强羰基化合物的ESI-MS 质谱信号，还可检测化合物中羰基的个数以及辨别涉及羰基官能团的同分异构体。此外，通过简单的氧化反应，还可将该方法拓展到三萜醇、甾醇等含羟基的低极性化合物，增强它们的ESI-MS 信号。对比已报道的相关ESI-MS 增强质谱信号的衍生化方法，此方法有经济、实用、快速和简便的显著特点。 第二章是关于野生羌活及其栽培品种化学成分的色谱-质谱联用分析。对不同产地野生羌活生长过程中活性成分的动态变化、野生羌活不同形态部位和人工栽培羌活中的活性成分含量进行了HPLC 定量分析。结果表明主要活性成分羌活醇和异欧前胡素都随生长期存在规律性变化，羌活不同形态部位中的活性成分含量也有明显不同。这些实验结果有些较好地印证了传统中医的用药理论，有些也对羌活的传统使用方法提出了新的建议。 第三章介绍了几种传统中藏药材的色谱-质谱联用及串联质谱分析。通过GC-MS 方法，从藏药材长花党参挥发油中共分离鉴定出45 个化合物；利用HPLC方法测定了该藏药材中的主要化学成分——木犀草素的含量（0.7%）；利用串联质谱技术，对西番莲和射干中的主要成分进行了快速鉴定，从西番莲中鉴定了4个黄酮碳苷；从不同产地的射干和川射干中鉴定了8 个主要异黄酮成分，其中包括一个未见报道的化合物。 第四章的内容为藏药材石莲叶点地梅的活性成分研究。从植物石莲叶点地梅(Androsace integra (Maxim.) Hand.-Mazz.) 乙醇提取物的正丁醇萃取部分共分离和鉴定了6 个化合物，利用MS 和NMR 等现代波谱学技术阐明了它们的结构：其中包括4 个三萜类化合物：分别是androsacin (1)、 ardisiacrispin A (2) 、saxifragifolin A (3) 和20(29)-lupen-3-one (4)；一个神经酰胺：4-羟基-Δ8,9(Z)-鞘氨醇-2'-羟基正二十四碳酸酰胺(5)；一个甾体类化合物：胡萝卜苷(6)。化合物1为新的13,28-epoxy-oleanane 型三萜皂苷，在其结构表征的过程中，采用LC-MS 进行糖分析，获得了值得推广的好结果。通过活性筛选发现化合物1~3 对HepG2肝癌细胞表现出不同程度的抑制活性，其中化合物2 活性最好，其IG50 为1.65μg/mL。 第五章是关于一些传统中藏药材的农药活性筛选。利用Syngenta 公司的活性筛选平台对68 种传统中藏药材醇提物进行了抗菌和除草的生物源农药活性筛选。结果表明所筛选的68 种植物提取物中，共有14 种样品表现出明显的除草/杀虫活性，其中水母雪莲花、松萝和茯神木等植物提取物还具有多种生物活性。活性成分还有待进一步追踪分离、纯化和结构鉴定。 第六章为文献综述，概述了羌活药材的研究进展。对羌活属及药用羌活植物从分类学、本草学、品质评价、人工栽培、化学成分及药理作用等方面进行了文献归纳和总结。 In this dissertation, an electrospray ionization mass spectrometry (ESI-MS) signal enhancement method, as well as the work of bioactive components study, HPLC-MS/MS application, bioassay screening, chromatograph separation and structure identification of the metabolites in several medicinal herbs have been reported. First chapter expounded a rapid, simple ESI-MS sensitivity enhancement method for detecting carbonyl groups in natural products has been developed by using hydroxylamine hydrochloride (NH2OH·HCl) as a derivatization reagent. We use the oxime formed during the derivatization reactions and its Beckmann rearrangement intermediates as a means of detecting the carbonyl groups originally present in these triterpenoids. In comparison with other derivatization methods in the literature, this method is simple, specific and can be used to detect carbonyl groups in triterpenoids which have low polarity and are poorly or non-ionizable. Moreover, it can also be used to detect hydroxyl groups by using the Dess-Martin periodinane (DMP) to convert primary and secondary hydroxyls into carbonyl groups. Chapter 2 reported an HPLC-MS method for analyzing the main bioactive compounds in both wild and cultured Notopterygium incisum. The results indicated that the main bioactive compounds varied through different seasons regularly, and in different commercial parts of this herb the content of these compounds also differed from each other. The quantitative analysis results showed that in the traditional commercial parts, the content of main chemical constitutes in Silkworm Notopterygium, Bamboo Notopterygium and Irregular-nodal Notopterygium are higher than that in Striped Notopterygium. This result is tally with the traditionally concept that the quality of Notopterygium, Bamboo Notopterygium and Irregular-nodal Notopterygium are better than that of Striped Notopterygium, which means that the quality of rhizomes is better than main roots. The chemical constituents of cultured N. incisum is reported for the first time in this dissertation and the analysis results showed some growth curves of chemical constituents in this plant, but still left some questions unanswered. Chapter 3 discussed the GC/LC-MS analysis of the traditional Chinese medicines Codonopsis thalictrifolis, Passiflora incarnate, Belamcanda chinensis and Passiflora incarnate. The main constituent, luteolin was isolated and identified from the traditional Tibet medicine of C. thalictrifolis. The quantitative analysis by HPLC has revealed that the content of luteolin in this herb is 0.7%. GC-MS was employed to analyzed chemical constituents of the essential oil from the flower of C. thalictrifolis. More than 60 peaks were detected and 45 of them were identified by comparing their spectra with that of the standards in the database and literatures. ESI-MS/MS was used to analyze the n-butanol extract of Passiflora incarnate. Based on the information of pseudo molecular ions and fragment ions of the glycosides, four major flavone-C-glycosides have been detected and identified as 7-methoxyluteolin-6-C-β-D-glucopyranoside, vitexin, swertisin and orientin. The isoflavone compounds in theextracts of three samples of B. chinensis collected in Gansu, Sichuan and Hunan, and the extract of Iris tectorum collected in Sichuan were analyzed by using TOF-HRMS and IT-MS. From the extracts of these herbs, a new isoflavone, identified as 5’,5,6,7-tetrahydroxy-3’4’-dimethoxyl isoflavon, and 7 known ones have been identified by analyzing the fragmentation patterns and their molecular formulas given by HRMS and the tandem mass spectrometry acquired by IT-MS. Chapter 4 elucidated the isolation and identification of a new triterpene saponin, androsacin (1), along with five known compounds (2-6) were isolated from the whole plants of Androsace integra (Maxim.) Hand.-Mazz., an herb used in traditional Chinese and Tibetan medicine. The chemical structure of the new compound was established as 3β-O-{β-D-glucopyranosyl-(1→4)-O-β-D-xylopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4)-[O-β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl}-16α-hydroxy-13β,28-epoxy-olean-30-al by analyzing its MS, 1D- and 2D-NMR spectra. Compound 2 was cytotoxic toward HepG2 cancer cell with the GI50 value of 1.65 μg/mL. Chapter 5 described the biogenic pesticide activity screening of 68 traditional Chinese and Tibetan medicine extractions. The intention of this study is to explore bioactive natural compounds from these traditional medicinal herbs for biogenic insecticides use. Based on Syngenta’s bioassay, 14 extractions of these traditional medicines showed pesticide activities, and some of them had multi-activities on antibacterial and insecticidal. Chapter 6 is a review on the chemical and bioactivity research progress of Notopterygium incisum and N. forbesii.

Screening of salt tolerant watercress variants on natural seawater contained medium

The responses of stem segments of watercress (Nasturtium officinale R. Br.) to 6-BA,NAA and 2,4-D were studied. MS medium supplemented with 2.0 mg/L 6-BA, 0.2 mg/L 2,4-D was used for callus initiation and maintenance. MS medium supplemented with 4.0 mg/L 6-BA was suitable for plant regeneration and MS medium without plant hormone supplement was used for rooting and plant propagation. For screening of salt tolerant calli, stem segments of watercress were plated onto callus initiation medium containing 1/3 natural seawater. Seventeen out of the 325 plated explants produced calli. The growth curves demonstrated that the growth rate of salt-tolerant calli on saline medium almost matched that of the control calli on normal medium. Some of the salt-tolerant calli were transferred to the normal regeneration medium or saline regeneration medium to induce plant regeneration. In the first case, buds and shoots were regenerated in the same way as those of control calli on normal regeneration medium. More than 1 000 regenerated shoots were obtained of which 83 regenerated shoots were cut and transferred to saline MS base medium. At first, all shoot growth was inhibited, but 40 days after the transfer, rapid-growing axillary shoots were observed on 16 of the original shoots but none on the control shoots on saline MS base medium. Moreover, green spots appeared on most calli 10 days after they were transferred to saline medium, however buds appeared only on 5 calli from the 30 transferred calli and at the end only 2 rapid-growing shoots were obtained from two calli. In total, 18 variant lines were obtained through. propagation of the salt-tolerant shoots on saline MS base medium. RAPD analysis was performed in 10 of the 18 salt-tolerant variant lines and DNA variation was detected in all the tested variant lines.

(Ga, Gd, As) film growth on GaAs substrate by low-energy ion-beam deposit

(Ga, Gd, As) film was fabricated by the mass-analyzed dual ion-beam epitaxy system with the energy of 1000 eV at room temperature. There was no new peak found except GaAs substrate peaks (0 0 2) and (0 0 4) by X-ray diffraction. Rocking curves were measured for symmetric (0 0 4) reflections to further yield the lattice mismatch information by employing double-crystal X-ray diffraction. The element distributions vary so much due to the ion dose difference from AES depth profiles. The sample surface morphology indicates oxidizing layer roughness is also relative to the Gd ion dose, which leads to islandlike feature appearing on the high-dose sample. One sample shows ferromagnetic behavior at room temperature. (C) 2003 Elsevier B.V. All rights reserved.

Growth and spectroscopic characteristics of Yb : GSO single crystal

For the first time, a high optical quality 10 at.% Yb3+-doped gadolinium oxyorthosilicate laser crystal Gd2SiO5 (GSO) was grown by the Czochralski (Cz) method. The segregation coefficient of Yb3+ was studied by the inductively coupled plasma atomic emission spectrometer (ICP-AES) method. The crystal structure has monoclinic symmetry with space group P2(1)/c; this was determined by means of an x-ray diffraction analysis. The absorption spectra, fluorescence spectra and fluorescence decay curves of Yb3+ ions in a GSO crystal at room temperature were also studied. Then, the spectroscopic parameters of Yb:GSO were calculated. The advantages of the Yb:GSO crystal include high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections and particularly broad emission bandwidth (similar to 72 nm). The results indicated that the Yb:GSO crystal seemed to be a very promising laser gain medium in diode-pumped femtosecond laser and tunable solid state laser applications when LD pumped at 940 and 980 nm.

Effects of ytterbium ion on the growth, metabolism and membrane fluidity of Tetrahymena thermophila

Power-time curves and metabolic properties of Tetrahymena thermophila BF5 exposed to different Yb3+ stop levels were studied by ampoule method of isothermal calorimetry at 28 degrees C. Metabolic rate (r) decreased significantly while peak time (PT) increased with the increase of Yb3+ stop. These results were mainly due to the inhibition of cell growth, which corresponded to the decrease of cell number obtained by cell counting. Compared with cell counting, calorimetry was sensible, easy to use and convenient for monitoring the toxic effects of Yb3+ stop on cells and freshwater ecosystem. It was also found that cell membrane fluidity decreased significantly under the effects of Yb3+ stop, which indicated that Yb3+ could be membrane active molecules with its effect on cell membranes as fundamental aspect of its toxicity.

Microcalorimetric investigation of the toxic action of Cr(VI) on the metabolism of Tetrahymena thermophila BF5 during growth

Tetrahymena thermophila BF5 produce heat by metabolism and movement. Using a TAM air isothermal microcalorimeter, the power-time curves of the metabolism of T thermophila BF5 during growth were obtained and the action on them by the addition of Cr(VI) were studied. The morphological change with Cr(VI) coexisted and biomass change during the process of T thermophila BF5 growth were studied by light microscope. Chromium has been regarded as an essential trace element for life. However, hexavalent chromium is a known carcinogen, mutagen, cytotoxicant and strong oxidizing agent. Cr(VI) of different concentration have different effects on T thermophila BF5 growth with the phenomenon of low dose stimulation (0-3 x 10(-5) mol L-1) and high dose inhibition (3 x 10(-5) to 2.4 x 10(-4) mol L-1). The relationship between the growth rate constant (k) and c is a typical U-shaped curve, which is a characteristic of hormesis. T thermophila BF5 cannot grow at all when the concentration of Cr(VI) is up to 2.4 x 10(-4) mol L-1. The microscopic observations agree well with the results obtained by means of microcalorimetry. And T thermophila BF5 had obviously morphological changes by the addition of Cr(VI). (c) 2006 Elsevier B.V. All rights reserved.

Growth of nonpolar a-plane GaN on nano-patterned r-plane sapphire substrates

Sapphire substrates were nano-patterned by inductive coupled plasma etching process. Nonpolar a-plane GaN films were grown on planar and nano-patterned r-plane sapphire substrates by metal organic chemical vapor deposition. The anisotropic characteristic and the crystalline quality of the a-plane GaN films were studied through XRD rocking curves. The cross section and surface morphologies of the a-plane GaN films were studied using SEM and AFM measurements, respectively. The crystal quality and surface flatness of the nonpolar a-plane GaN were greatly improved through the usage of the nano-patterned r-plane sapphire substrates. (C) 2008 Elsevier B.V. All rights reserved.

Growth of CeO2 : Bi12SiO20 crystals in multi-position furnace(II) - Space growth experiment

Ce-doped Bi12SiO20 single crystal with size of phi10mm x 40mm was successfully grown in space on board of the spacecraft Shenzhou No.3. The surface morphology of space-grown crystal is different from that of ground-grown crystal The space- and ground-grown crystals were measured by X-ray rocking curves, absorption spectra and micro-Raman spectra. The results show that the quality of Ce-deped crystal grown in space is better than that of the ground-grown one. The effect of doping on optical properties of BSO grown in space is evident in comparison with the ground-grown crystal.

(Ga, Gd, As) film growth on GaAs substrate by low-energy ion-beam deposit

(Ga, Gd, As) film was fabricated by the mass-analyzed dual ion-beam epitaxy system with the energy of 1000 eV at room temperature. There was no new peak found except GaAs substrate peaks (0 0 2) and (0 0 4) by X-ray diffraction. Rocking curves were measured for symmetric (0 0 4) reflections to further yield the lattice mismatch information by employing double-crystal X-ray diffraction. The element distributions vary so much due to the ion dose difference from AES depth profiles. The sample surface morphology indicates oxidizing layer roughness is also relative to the Gd ion dose, which leads to islandlike feature appearing on the high-dose sample. One sample shows ferromagnetic behavior at room temperature. (C) 2003 Elsevier B.V. All rights reserved.

Low-temperature growth of InN by MOCVD and its characterization

Metalorganic chemical vapor deposition growth of InN on sapphire substrate has been investigated between 400 degrees C and 500 degrees C to seek the growth condition of InN buffer layer, i.e. the first step of realization of the two-step growth method. Ex situ characterization of the epilayers by means of atomic force microscope, scanning electron microscope and X-ray diffraction, coupled with in situ reflectance curves, has revealed different growth circumstances at these temperatures, and conclusion has been reached that the most suitable temperature for buffer growth is around 450 degrees C. In addition, the growth rate of InN at the optimized temperature with regard to different precursor flow rates is studied at length. (c) 2004 Elsevier B.V. All rights reserved.

Selective area growth of GaN on GaAs(001) substrates by metalorganic vapor-phase epitaxy

Selective area growth (SAG) of GaN on SiO2 stripe-patterned GaN/GaAs(001) substrates was carried out by metalorganic vapor-phase epitaxy. The SAG samples were investigated by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). SEM observations showed that the morphology of SAG GaN is strongly dependent on the window stripe orientation and slightly affected by the orientation relationship between the window stripes and the gas flow. The (I 1 1)B sidewalls formed on the SAG GaN stripes are found to be stable. XRD measurements indicated the full-widths at half-maximum (FWHMs) of cubic GaN (0 0 2) rocking curves are reduced after SAG. The measured FWHMs with omega-axis parallel to [1(1) over bar 0] are always larger than the FWHM values obtained with omega-axis parallel to [I 10], regardless of the orientation relationship between the w-axis and the GaN stripes. (C) 2003 Elsevier Science B.V. All rights reserved.