Determination of alkali-labile phosphoprotein phosphorus from fish plasma using the Tb^3＋-tiron complex as a fluorescence probe

A sensitive method based on the fluorescence quenching effect of the Tb^3＋-Tiron complex is proposed for the determination of alkali-labile phosphoprotein phosphorus （ALP） released from fish plasma. The detection limit was 5.4 ng/ml （S/N=2）, and the relative standard deviation of the quenching effect （6 replicates） was 4.6%. The results obtained by the proposed method were in good agreement with those obtained by the colorimetric assay. The advantages of the present method are its relatively simple detection procedure, the lack of toxic organic solvents, and high sensitivity.     

Toxicological studies of zinc oxide nanomaterials in rats

In this study, we have evaluated the ability of zinc oxide (ZnO) nanoparticles to induce pulmonary and extrapulmonary toxicities was examined in rats following intratracheal (IT) instillation. Lungs of rats were instilled IT with either phosphate-buffered saline (PBS)?+?1% Tween 80, ZnO nanoparticles, carbonyl iron or quartz particles at a dose of 1 or 5?mg?kg^?1 body weight. Following exposure, bronchoalveolar lavage (BAL) fluid, blood samples and organs including lung, liver, kidneys, heart, pancreas, and brain were collected at 24?h, 1 week, or 1 month of post instillation of nanoparticles and different parameters estimated to assess toxicity. BAL fluid was analyzed for lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) to assess pulmonary toxicity. Exposures to ZnO or quartz particles produced transient dose-dependant increase in BAL fluid LDH and ALP activities at all post exposure periods. Blood samples were analyzed for the tissue damage biomarkers to assess extrapulmonary toxicity. Histopathological examination of lung, liver and kidneys revealed dose-dependent degeneration and necrosis which worsened at 1 week post-instillation periods but recovered at 1 month post instillation. Histopathological examination of rat pancreas, heart, and brain exposed to quartz or ZnO particles showed no marked changes. Data suggest the instillation of ZnO nanoparticles produced a greater pulmonary toxicity in rats comparable with quartz; and extrapulmonary toxicities of these ZnO nanoparticles might be due to translocation into liver and kidney.     

钐染毒对小鼠脏器系数和睾丸酶活性的影响

为了研究稀土元素钐对雄性小鼠脏器系数和睾丸内酶活性的影响,将小鼠分组分别自由饮用含硝酸钐0,4,20,100,500mg/L的水,3个月后处死小鼠,称量体重和主要脏器重量,并测定睾丸内乳酸脱氢酶(LDH)、酸性磷酸酶(ACP)、碱性磷酸酶(ALP)和三磷酸腺苷酶(ATP酶)活力.结果表明,20,100mg/L剂量组小鼠附睾脏器系数明显低于对照组;100,500mg/L剂量组LDH酶活力明显受到抑制,且染毒剂量与LDH酶活力呈剂量-反应关系;各处理组ALP酶活力明显升高,而ACP酶活力不受影响;3种ATP酶活力都随钐浓度的增加有“低促高抑”的趋势.钐亚慢性染毒对小鼠生殖性腺具有一定的毒性作用,其中LDH和ALP可作为稀土元素钐作用于睾丸的标志酶.     

Dynamic evaluation of land productivity in China

For making rational and scientific land-use planning,an inventory indicator of land productivity subject to biophysical limitations and human disturbance is required.This study introduces agricultural land productivity(ALP)as the dynamic indicator to measure land productivity,involving factors that affect agricultural production,such as characteristics of climate,soil,and terrain.As a case study of this dynamic indicator,ALP was estimated at county level and aggregated into provincial level in the whole of China.The result shows that ALP increased during 2000-2010 in China,and the ratios of ALP to the actual grain yield were 65.40%and 66.38%in the years 2000 and 2005,respectively.The ALP is an effective dynamic indicator to estimate the land productivity and to represent the basic conditions about the supply of water,energy,nutrients,and the physical basis for plant growth,as well as the local input.ALP estimation could provide supporting information for policy-making about land production planning and land-use management.     

DEP、DOP暴露对鲤鱼的酸碱性磷酸酶的影响

为了研究酞酸酯类对水生生物的毒性作用,将鲤鱼暴露于DEP与DOP的6个质量浓度组中进行96h-LC50急性毒性试验,测得其半致死质量浓度(96 h-LC50)分别为41.50mg/L与7.95 mg/L。分别设置3个质量浓度和1个对照组,测定DEP与DOP对鲤鱼肝脏及肌肉组织酸性磷酸酶(ACP)与碱性磷酸酶(ALP)活性的影响。结果表明:DEP与DOP对鲤鱼肝脏及肌肉组织ACP活性的影响趋势均表现为低质量浓度诱导,高质量浓度抑制;DEP对鲤鱼肝脏及肌肉组织ALP活性的影响亦表现为低质量浓度诱导,高质量浓度抑制;而DOP对鲤鱼肝脏ALP活性的影响表现为随着暴露质量浓度的增大而活性降低,呈现出明显的剂量-效应关系。酸性磷酸酶和碱性磷酸酶可能在鱼体抵御酞酸酯毒性作用中有重要作用,其机理有待进一步研究。