Dinoflagellate Cysts Records from Core Samples of Modern Marine Sediment at the Luoyuan Bay Mouth

Thirty species of dinoflagellate cysts in 15 genus are identified from KMZK5 Core samples of recent marine sediment at the Luoyuan Bay mouth, Fujian. All of these dinoflagellate cysts are first recorded in the Luyuan Bay, 12 species of them are not distributing in the near sea area such as Sansha Bay and Minjiang estuary, including 6 kinds of toxic species, such as Alexandrium affine, A. minutum, A. tamarense, Gonyaulax spinifera, Gymnodinium catenatum and Scrippsiella trochoidea. The abundance and vertical distribution characterestics of the main and the toxic dinoflgellate cysts are also studied in the paper.

Comparative cytotoxicity of fourteen trivalent and pentavalent arsenic species determined using real-time cell sensing

The occurrence of a large number of diverse arsenic species in the environment and in biological systems makes it important to compare their relative toxicity. The toxicity of arsenic species has been examined in various cell lines using different assays, making comparison difficult. We report real-time cell sensing of two human cell lines to examine the cytotoxicity of fourteen arsenic species： arsenite（As~Ⅲ）, monomethylarsonous acid（MMA~Ⅲ） originating from the oxide and iodide forms, dimethylarsinous acid（DMA~Ⅲ）, dimethylarsinic glutathione（DMAG~Ⅲ）, phenylarsine oxide（PAO~Ⅲ）, arsenate（AsV）, monomethylarsonic acid（MMA~Ⅴ）, dimethylarsinic acid（DMA~Ⅴ）,monomethyltrithioarsonate（MMTTA~Ⅴ）, dimethylmonothioarsinate（DMMTA~Ⅴ）,dimethyldithioarsinate（DMDTA~Ⅴ）, 3-nitro-4-hydroxyphenylarsonic acid（Roxarsone, Rox）,and 4-aminobenzenearsenic acid（p-arsanilic acid, p-ASA）. Cellular responses were measured in real time for 72 hr in human lung（A549） and bladder（T24） cells. IC50 values for the arsenicals were determined continuously over the exposure time, giving rise to IC50 histograms and unique cell response profiles. Arsenic accumulation and speciation were analyzed using inductively coupled plasma-mass spectrometry（ICP-MS）. On the basis of the 24-hr IC50 values, the relative cytotoxicity of the tested arsenicals was in the following decreasing order： PAO~Ⅲ？ MMA~Ⅲ≥ DMA~Ⅲ≥ DMAG~Ⅲ≈ DMMTA~Ⅴ≥ As~Ⅲ？ MMTTA~Ⅴ〉 AsV〉 DMDTA~Ⅴ〉DMA~Ⅴ〉 MMA~Ⅴ≥ Rox ≥ p-ASA. Stepwise shapes of cell response profiles for DMA~Ⅲ, DMAG~Ⅲ,and DMMTA~Ⅴcoincided with the conversion of these arsenicals to the less toxic pentavalent DMA~Ⅴ. Dynamic monitoring of real-time cellular responses to fourteen arsenicals provided useful information for comparison of their relative cytotoxicity.

Reactive oxidative species enhance amyloid toxicity in APP/PS1 mouse neurons

Objective To investigate whether intracellular amyloid β （iAβ） induces toxicity in wild type （WT） and APP/PS1 mice, a mouse model of Alzheimer＇s disease. Methods Different forms of Aβ aggregates were microinjected into cultured WT or APP/PS1 mouse hippocampal neurons. TUNEL staining was performed to examine neuronal cell death. Reactive oxidative species （ROS） were measured by MitoSOXTM Red mitochondrial superoxide indicator. Results Crude, monomer and protofibrilAβ induced more toxicity inAPP/PS1 neurons than in WT neurons. ROS are involved in mediating the vulnerability of APP/PS1 neurons to iAβ toxicity. Conclusion Oxidative stress may mediate cell death induced by iAβ in neurons.