Simultaneous determination nucleosides in marine organisms using ultrasound-assisted extraction followed by hydrophilic interaction liquid chromatography-electrospray ionization time-of-flight mass spectrometry

A new method has been developed based on ultrasound-assisted extraction (UAE) followed by hydrophilic interaction chromatography (HILIC) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) for the simultaneous determination of 16 nucleosides and nucleobases in medicinal extracts of various marine organisms. The separation was achieved on a Venusil HILIC column (250×4.6 mm id, 5 μm) and gradient elution using a solution of acetonitrile and buffer (0.20% formic acid and 20 mmol/L ammonium acetate) as the mobile phase. Identification of the 16 target nucleosides and nucleobases was based on the retention time, UV spectra, and mass measurements of the protonated molecules ([M+H](+)) and main fragment ions (ESI-TOF/MS). In addition, non-target compounds of 2'-deoxyinosine and four other amino acids were also tentatively identified by ESI-TOF/MS. The 16 target compounds were quantified by HILIC-ESI-TOF/MS under optimized mass conditions. All calibration curves showed good linearity (r(2)>0.9951). The recoveries were 84.72-124.10%, and the limits of detection of the 16 target compounds were 0.6-130.0 ng/mL. The developed method was applied to quantify the target compounds in 15 batches of various marine organisms. The method has potential applicability for the identification and determination of highly polar and low-concentration active compounds in marine organisms.     

Flow-based in vivo NMR spectroscopy of small aquatic organisms

NMR applied to living organisms is arguably the ultimate tool for understanding environmental stress responses and can provide desperately needed information on toxic mechanisms, synergistic effects, sublethal impacts, recovery, and biotransformation of xenobiotics. To perform in vivo NMR spectroscopy, a flow cell system is required to deliver oxygen and food to the organisms while maintaining optimal line shape for NMR spectroscopy. In this tutorial, two such flow cell systems and their constructions are discussed: (a) a single pump high-volume flow cell design is simple to build and ideal for organisms that do not require feeding (i.e., eggs) and (b) a more advanced low-volume double pump flow cell design that permits feeding, maintains optimal water height for water suppression, improves locking and shimming, and uses only a small recirculating volume, thus reducing the amount of xenobiotic required for testing. In addition, key experimental aspects including isotopic enrichment, water suppression, and 2D experiments for both ¹³C enriched and natural abundance organisms are discussed.     

Natural Products from Tongan Marine Organisms

The islands of the South Pacific Ocean have been in the limelight for natural product biodiscovery, due to their unique and pristine tropical waters and environment. The Kingdom of Tonga is an archipelago in the central Indo-Pacific Ocean, consisting of 176 islands, 36 of which are inhabited, flourishing with a rich diversity of flora and fauna. Many unique natural products with interesting bioactivities have been reported from Indo-Pacific marine sponges and other invertebrate phyla; however, there have not been any reviews published to date specifically regarding natural products from Tongan marine organisms. This review covers both known and new/novel Marine Natural Products (MNPs) and their biological activities reported from organisms collected within Tongan territorial waters up to December 2020, and includes 109 MNPs in total, the majority from the phylum Porifera. The significant biological activity of these metabolites was dominated by cytotoxicity and, by reviewing these natural products, it is apparent that the bulk of the new and interesting biologically active compounds were from organisms collected from one particular island, emphasizing the geographic variability in the chemistry between these organisms collected at different locations.     

基于太赫兹光谱技术与CS-SVM的转基因产品鉴别

提出了一种基于太赫兹(THz)光谱技术以及布谷鸟搜索(CS)算法优化支持向量机(SVM)的有效的转基因产品鉴别方法(CS-SVM)。实验采用太赫兹时域光谱(THz-TDS)系统测量了三种转基因大豆种子及其亲本样品在0.2~1.2 THz波段的THz光谱,并采用SVM方法对转基因和非转基因大豆种子进行了分类鉴别研究,其中SVM的两个重要参数(惩罚因子和核参数)采用CS算法进行优化。实验结果表明,应用THz光谱技术结合CS-SVM方法为转基因和非转基因生物的检测和识别提供了一种快速、无损和可靠的分析方法。     

武汉东湖的污染现状与可持续发展对策研究

通过对武汉东湖４０多年来的水生生物、周边环境和水质变化的分析比较，论述了东湖生态系统的人为干扰和变化情况，在对东湖的环境容量研究计算以及最大可持续养鱼量分析的基础上，结合东湖水体的综合功能，提出了武汉东湖可持续发展的对策．     

单细胞水生生物金属纳米颗粒的定量分析

人类活动释放的金属纳米颗粒不可避免地进入水环境中。大量研究表明,金属纳米颗粒会对水生生物产生生殖毒性和遗传毒性等,金属纳米颗粒还可能沿着食物链传递,对环境生物和人类健康造成威胁。细胞内金属纳米颗粒定量分析是研究金属纳米颗粒生物效应的重要基础。此外,单细胞之间存在异质性,具有特殊生理特性的细胞个体可能影响细胞群体的命运。而基于细胞群体平均值的定量分析则忽略了细胞个体的异质性,遗漏了对群落具有重要功能的细胞群体信息。因此,在单细胞水平上定量分析水环境中底层营养级的单细胞微生物细胞内金属纳米颗粒,对认识金属纳米颗粒与水生生物的相互作用,评估其进入食物链的潜在风险至关重要。本文梳理了已用于单细胞水生生物体内金属纳米颗粒的单细胞定量分析方法,阐述了它们的工作原理和在相关研究中的应用,总结了各方法的优缺点,期望为今后相关研究的方法选择提供参考,最后展望了该领域未来的研究方向。     

Application of cadmium sulfide nanoparticles as oligonucleotide labels for the electrochemical detection of NOS terminator gene sequences

A mercaptoacetic acid (MAA)-modified cadmium sulfide (CdS) nanoparticle was synthesized in aqueous solution and used as an oligonucleotide label for the electrochemical detection of nopaline synthase (NOS) terminator gene sequence. The carboxyl groups on the surface of the CdS nanoparticle can be easily covalently linked with NH₂-modified NOS oligonucleotide probe sequences. The target ssDNA sequence was fixed onto the electrode surface by covalently linking to a mercaptoethanol self-assembled gold electrode, and the DNA hybridization of target ssDNA with probe ssDNA was accomplished on the electrode surface. The CdS nanoparticles anchored on the hybrids were dissolved in the solution by the oxidation with HNO₃ and further detected by a sensitive differential pulse anodic stripping voltammetric method. The detection results can be used for monitoring the hybridization, and the NOS target sequence was satisfactorily detected in the approximate range from 8.0 × 10⁻¹² to 4.0 × 10⁻⁹ mol L⁻¹ with a detection limit of 2.75 × 10⁻¹² mol L⁻¹ (3σ). The established method extended the nanoparticle-labeled electrochemical DNA analysis to genetically modified organisms (GMOs) specific sequence samples with higher sensitivity and selectivity.     

Study of a X-ray laser-plasma source for radiobiological experiments: microdosimetry analysis and plasma characterisation

A soft X-ray laser-plasma source, used in radiobiology experiments with yeast cells, was characterised with flat crystal spectrometers and P-I-N diodes, obtaining an absolute measurement of the emission spectrum. A comparison with the results of simulations performed with the code RATION allowed the characterisation of the emitting plasma. A model for the energy deposition in yeast cells was developed to take into account the different cell structures (wall-membrane complex, cytoplasm and nucleus). Dose calculations performed considering the source emission spectrum were compared with direct measurements of transmission through plastic foils and allowed to verify the hypothesis of preferential dose deposition in the outer cellular regions. Received 16 September 1999 and Received in final form 1st February 2000     

Determination of PCR products by CE with contactless conductivity detection

The use of CE with contactless conductivity detection for the determination of PCR products is demonstrated for the first time. The separation of specific length PCR products according to their size could be achieved using 5% PVP as a sieving medium in a separation buffer consisting of 20 mM Tris and 20 mM 2‐(cyclohexylamino)ethansulphonic acid (pH 8.5). A fused silica capillary of 60 cm length and 50 μm id and an applied separation voltage of –15 kV were employed and separations could be completed within 20–50 min. PCR amplified DNA fragments of different sizes obtained from different bacterial plasmid templates as well as a fragment from genomic DNA of genetically modified soybeans could be successfully identified.