Autophagy and ethanol neurotoxicity

Excessive ethanol exposure is detrimental to the brain. The developing brain is particularly vulnerable to ethanol such that prenatal ethanol exposure causes fetal alcohol spectrum disorders (FASD). Neuronal loss in the brain is the most devastating consequence and is associated with mental retardation and other behavioral deficits observed in FASD. Since alcohol consumption during pregnancy has not declined, it is imperative to elucidate the underlying mechanisms and develop effective therapeutic strategies. One cellular mechanism that acts as a protective response for the central nervous system (CNS) is autophagy. Autophagy regulates lysosomal turnover of organelles and proteins within cells, and is involved in cell differentiation, survival, metabolism, and immunity. We have recently shown that ethanol activates autophagy in the developing brain. The autophagic preconditioning alleviates ethanol-induced neuron apoptosis, whereas inhibition of autophagy potentiates ethanol-stimulated reactive oxygen species (ROS) and exacerbates ethanol-induced neuroapoptosis. The expression of genes encoding proteins required for autophagy in the CNS is developmentally regulated; their levels are much lower during an ethanol-sensitive period than during an ethanol-resistant period. Ethanol may stimulate autophagy through multiple mechanisms; these include induction of oxidative stress and endoplasmic reticulum stress, modulation of MTOR and AMPK signaling, alterations in BCL2 family proteins, and disruption of intracellular calcium (Ca2+) homeostasis. This review discusses the most recent evidence regarding the involvement of autophagy in ethanol-mediated neurotoxicity as well as the potential therapeutic approach of targeting autophagic pathways.     

阿胶冲剂与阿胶的化学成分对比分析研究

阿胶在我国有着悠久的历史,是常用滋补中药,具有许多特殊的功效,国内外享有盛誉。据《本草纲目》及《本草纲目拾遗》等介绍,阿胶在明代以前系用(沙牛)牛,水牛,驴皮或猪、马、驼皮等杂皮熬制而成。自清代始一律采用黑驴皮熬制。以往服用阿胶必须将阿胶先用水浸泡后,然后加热溶解后才能服用.为了克服这一缺点,山东化工学院研制了一种用开水冲服的阿胶新制剂——阿胶冲剂.为了弄清阿胶经物理方法处理后的化学组成成份与原阿谱的化学组成成分的不同变化。我们对其所含微量元素、氨基酸进行了对比分析.另外,本文首次报道了阿胶及阿胶冲剂的红外光谱分析结果.     

The effects of centrally administered fluorocitrate via inhibiting glial cells on working memory in rats

Although prefrontal and hippocampal neurons are critical for spatial working memory, the function of glial cells in spatial working memory remains uncertain. In this study we investigated the function of glial cells in rats’ working memory. The glial cells of rat brain were inhibited by intracerebroventricular (icv) injection of fluorocitrate (FC). The effects of FC on the glial cells were examined by using elec-troencephalogram (EEG) recordings and delayed spatial alternation tasks. After icv injection of 10 μL of 0.5 nmol/L or 5 nmol/L FC, the EEG power spectrum recorded from the hippocampus increased, but the power spectrum for the prefrontal cortex did not change, and working memory was unaffected. Fol-lowing an icv injection of 10 μL of 20 nmol/L FC, the EEG power spectra in both the prefrontal cortex and the hippocampus increased, and working memory improved. The icv injection of 10 μL of 50 nmol/L FC, the EEG power spectra in both the prefrontal cortex and in the hippocampus decreased, and working memory was impaired. These results suggest that spatial working memory is affected by cen-trally administered FC, but only if there are changes in the EEG power spectrum in the prefrontal cortex. Presumably, the prefrontal glial cells relate to the working memory.     

Identification of diacylglycerol-O-(N,N,N-trimethyl)-homoserine in the halotolerant alga, Dunaliella parva

An unusual zwitterionic polar lipid component isolated from the halotolerant alga, Dunaliella parva Lerche, has been identified as 1(3),2-diacylglyceryl-3(1)-O-4′-(N,N,N-trimethyl) homoserine by means of infrared spectrometry, ¹H- and ¹³C-NMR spectrometry and field desorption mass spectrometry of the intact lipid, as well as by its TLC mobilities and staining behaviour. Mass spectrometry of this lipid indicated the presence of the following major molecular species: 16:0–18:0 (24%); 18:3–18:3 (19%); 16:0–18:2 (16%); 16:0–18:1 (8%).     

Fabrication and characterization of noble crystalline silver nanoparticles from Pimenta dioica leave extract and analysis of chemical constituents for larvicidal applications

The current works report the bio-efficacy of Pimenta dioica leaf derived silver nanoparticles (Pd@AgNPs) and leaf extract obtained trough different solvents against the larvae of malaria, filarial and dengue vectors. Synthesis of silver nanoparticles (AgNPs) was done by adding 10 ml of P. dioica leaf extract into 90 ml of 1 mM silver nitrate solution, a slow colour change was observed depicting the formation of AgNPs. Further, Pd@AgNPs was confirmed through Ultraviolet–visible spectroscopy which exhibited characteristic absorption peak at 422 nm wavelength. X-ray diffraction and selected area electron diffraction analysis confirmed monodispersed and crystalline nature of Pd@AgNPs with 32 nm an average size. Scanning electron microscopy and transmission electron microscopy showed the most of Pd@AgNPs were spherical and triangular in shape and energy-dispersive X-ray spectroscopy revealed silver elemental nature of nanoparticles. Zeta potential of Pd@AgNPs is highly negative which confirmed its stable nature. Pd@AgNPs showed prominent absorption peaks at 1015, 1047, 1243, 1634, 2347, 2373, 2697 and 3840 cm^?1 which are corresponding to following compounds polysaccharides, carboxylic acids, water, alcohols, esters, ethers, amines, amides and phenol, respectively as reported by Fourier-transform infrared spectroscopy analysis. Gas chromatography–mass spectrometry and Liquid chromatography–mass spectrometry analysis revealed 39 and 70 compounds, respectively, which might be contributed for bio-reduction, capping, stabilization and larvicidal behavior of AgNPs. A comparable lethality (LC₅₀ and LC₉₀) was observed in case of Pd@AgNPs over leaf extract alone. The potential larvicidal activity of Pd@AgNPs was observed against the larvae of Aedes aegypti,(LC_50, 2.605; LC_90, 5.084 ppm) Anopheles stephensi (LC_50, 3.269; LC_90, 7.790 ppm) and Culex quinquefasciatus (LC_50, 5.373; LC_90, 14.738 ppm without affecting non-targeted organism, Mesocyclops thermocyclopoides after 72 hr of exposure. This study entails green chemistry behind synthesis of AgNPs which offers effective technique for mosquito control and other therapeutic applications.     

落叶阔叶林反照率的时间变化与影响因素

反照率原位测量对生态系统能量收支及其遥感应用至关重要,但目前坡面地形反照率的测量方式有局限且可见光与近红外波段反照率时间变化的差异尚不清楚。本研究以东北地区帽儿山森林生态站的落叶阔叶林为例,探究入射和反射太阳辐射(SR,300～2800 nm)、光合有效辐射(PAR,400～700 nm)、近红外辐射(NIR,700～2800 nm)的反照率时间变化特征及其影响因子,同时分析了两种辐射表安装方式反照率的差异。结果表明: 晴天SR和NIR反照率日变化呈上下午不对称的U型曲线,但PAR从早到晚递增;阴天反照率均先急剧下降后趋于稳定。平行于坡面测量增大了反照率的日均值,但缓和了SR、NIR反照率日不对称的现象。从整个生长季来看,SR、NIR与PAR反照率水平测量时最大值分别为0.16、0.27和0.11,最小值分别为0.07、0.11和0.03。SR和NIR反照率季节变化均为先增大后减小(7月为峰值),PAR则相反,SR反照率主要受NIR而不是PAR控制。各波段反照率季节变化的影响因子按照贡献率排序为宽带归一化植被指数(61.7%～78.5%,可表征叶面积指数)>太阳高度角(15.4%～36.9%)>晴空指数(0.4%～36.9%)。     

红外成像技术在生命科学中的应用

红外成像技术是利用物体自身各部分对红外热辐射的差异把红外辐射图像转换为可视图像的技术.对红外成像技术历史进行了简单介绍,对远红外成像技术在生命科学包括医学、植物、动物及农业中的应用进行了综述,并对红外成像技术在生命科学中的应用作了展望.     

The Effects of Infrared Loading and Water Table on Soil Energy Fluxes in Northern Peatlands

Increased radiative forcing is an inevitable part of global climate change, yet little is known of its potential effects on the energy fluxes in natural ecosystems. To simulate the conditions of global warming, we exposed peat monoliths (depth, 0.6 m; surface area, 2.1 m²) from a bog and fen in northern Minnesota, USA, to three infrared (IR) loading (ambient, +45, and +90 W m^–2) and three water table (–16, –20, and –29 cm in bog and –1, –10 and –18 cm in fen) treatments, each replicated in three mesocosm plots. Net radiation (Rn) and soil energy fluxes at the top, bottom, and sides of the mesocosms were measured in 1999, 5 years after the treatments had begun. Soil heat flux (G) increased proportionately with IR loading, comprising about 3%–8% of Rn. In the fen, the effect of IR loading on G was modulated by water table depth, whereas in the bog it was not. Energy dissipation from the mesocosms occurred mainly via vertical exchange with air, as well as with deeper soil layers through the bottom of the mesocosms, whereas lateral fluxes were 10–20-fold smaller and independent of IR loading and water table depth. The exchange with deeper soil layers was sensitive to water table depth, in contrast to G, which responded primarily to IR loading. The qualitative responses in the bog and fen were similar, but the fen displayed wider seasonal variation and greater extremes in soil energy fluxes. The differences of G in the bog and fen are attributed to differences in the reflectance in the long waveband as a function of vegetation type, whereas the differences in soil heat storage may also depend on different soil properties and different water table depth at comparable treatments. These data suggest that the ecosystem-dependent controls over soil energy fluxes may provide an important constraint on biotic response to climate change.