慢性氨氮胁迫对黄颡鱼摄食、生长及血液指标的影响

挑选规格相近的健康黄颡鱼幼鱼分别饲养在氨氮浓度为3.36 mg L-1(A1)、6.72 mg L-1(A2)、13.44 mg L-1(A3)、26.88 mg L-1(A4)的水体中,对照组(A0)用不加外源氨氮的自然晾晒的自来水饲养.每组放养试验鱼30尾,暴露56d.结果表明,非离子氨对黄颡鱼幼鱼的摄食、生长及血液指标存在显著影响(P<0.05),而对鱼体成分的影响不显著(P>0.05).随着非离子氨浓度升高,高浓度组摄食率明显下降,饲料利用率降低,生长缓慢,特定生长率(Specialgrowth rate,SGR)和存活率都较对照组低.血氨浓度随非离子氨浓度升高而显著升高(P<0.01),各处理组血氨浓度远低于其所处环境总氨氮(Total ammonia,TAN)浓度,而血浆尿素氮(Urea nitrogen,Ur-N)水平逐渐降低但差异不显著.A3和A4碱性磷酸酶(k p p,AKP)活性和皮质醇(Cortisol)水平升高较快,A1和A2尽管呈上升趋势,但与对照组差异不显著(P>0.05).血糖(Glucose,GLU)浓度总体上表现为降低的趋势,2个高浓度组(A3和A4)下降速度较快.谷丙转氨酶(Alamine aminotransferase,ALT)和谷草转氨酶(Aspartate aminotransferase,AST)活性总体呈升高趋势,非离子氨浓度越大其升高趋势越明显.因此,黄颡鱼幼鱼不宜长期生活在高浓度的氨氮胁迫环境中,适宜的养殖水体中氨氮应该保持在低于6.72 mg L-1水平.     

Effect of a popular Middle Eastern food (Falafel) on rat liver

The aim of this study was to evaluate the effect of short-term consumption of oil and frying oil extracted from falafel patties, and then to study the long-term effect of consumption of falafel patties on rat liver gross morphology and serum liver enzymes. The frying oil quality was assessed using thiobarbituric acid reaction on rat liver homogenate. Frying oil and oil extracted from falafel patties were administered to male Wistar albino rats via gavage for 5 days. Blood samples were collected and the activities of alkaline phosphatase (ALP), aspartate aminotransferase, alanine aminotransferase (ALT), and bilirubin levels were determined. Livers were weighed and gross morphology was assessed. For the long-term effect of falafel consumption, rats were fed falafel patties for 30 days, and then blood samples were collected and assayed for the above-mentioned parameters. Short-term consumption of falafel extracts and frying oil did not cause any significant difference in the liver function tests and liver gross morphology. Whereas, long-term consumption of falafel patties caused a significant increase in ALP, ALT, bilirubin level and increased liver weight/body weight ratio denoting hepatotoxicity. This indicates that consumption of large amounts of falafel on daily basis might lead to hepatotoxicity.     

水稻根系生长发育对CO2浓度升高的响应及其品种间的差异

Minirhizontrons是一种非破坏性、定点、可直接观测和研究植物根系的新方法。利用微根管Minirhizotrons在试验田的温室大棚内研究CO2浓度升高作用下的水稻根系生长发育,试验采用完全随机处理,探讨CO2浓度升高（800μmol·mol-1）对水稻（Oryza sativa L.）生物量和根系形态的变化差异。结果表明,与CO2对照相比,CO2浓度升高显著增加4个水稻品种（2种杂交籼稻和2种常规籼稻）的地上部生物量,增幅为8.58%-12.66%,平均增加10.61%。CO2浓度升高条件下,根的生物量分别增加了3.16%-12.13%,平均增加8.64%。高CO2浓度对根系形态的影响表明,4种水稻根系对CO2浓度升高都有积极的响应。CO2浓度升高条件下,各根系指标在水稻不同生育期都有显著增加,根长密度、表面积、体积和根数的平均增幅分别为10%-27%、21%-24%、20%-58%和4%-18%。但在水稻生长发育过程中,品种间也存在着差异。CO2浓度升高和对照处理,籼型杂交稻威优644（V644）和金优207（JY207）的根长密度和根数表现出相似的变化趋势;高CO2浓度处理时其根长密度平均都增加了10%,根数平均增加4%和8%。CO2浓度升高和对照处理,2种籼型杂交水稻的根体积和表面积表现出较快的增长幅度,都呈现出近线性的生长趋势;CO2浓度升高处理下其根体积平均增加40%和25%,表面积平均都增加了24%。CO2浓度升高和对照处理,籼型常规稻湘晚12号（XW12）和丰华占（FHZ）的生长变化趋势表现一致,生长发育后期达到一个近似饱和的拐点。CO2浓度升高条件下其根长密度、根数和根体积分别平均增加27%和24%、18%和11%、58%和20%,根表面积平均都增加了21%。     

地表臭氧增加对黄花夹竹桃和芒果叶片膜脂过氧化程度和保护酶活性的影响

以黄花夹竹桃（Thevetia peruviana（Pers.）k.Schum.）和芒果（Mangifera indica L.）苗木为材料,研究4种臭氧（O3）体积分数[环境大气NF,φ（O3）=10×10-9~20×10-9;低体积分数处理E50,φ（O3）=50×10-9;中体积分数处理E100,φ（O3）=100×10-9;高体积分数处理E200,φ（O3）=200×10-9]下两种植物叶片膜脂过氧化程度、可溶性蛋白质质量分数、可溶性糖质量分数和保护酶活性的变化情况,旨在揭示地表臭氧体积分数升高条件下2种植物生理代谢活动变化机理及响应规律。结果表明：随臭氧体积分数的增加,2种植物丙二醛含量和膜透性均逐渐上升,且与臭氧体积分数呈显著正相关关系,说明两种植物膜脂过氧化程度加剧;低体积分数O3处理时两种植物可溶性蛋白质量分数均逐渐下降,高φ（O3）处理后小幅回升;黄花夹竹桃可溶性糖质量分数逐渐下降,芒果先上升后下降;2种植物的POD活性均显著上升,但上升幅度有较大差异;2种植物的CAT活性均呈先升高再降低的趋势。研究表明,不同体积分数的臭氧暴露下,黄花夹竹桃和芒果均受到不同程度的伤害,芒果对臭氧表现出较强的抗性,黄花夹竹桃对臭氧较敏感。     

基于BP神经网络算法的密云水库水质参数反演研究

密云水库是北京市重要的地表饮用水源地,在保障首都水源安全方面起着重要作用,而密云水库水质参数的区域监测已成为当前亟待解决的问题。为了实现密云水库水质参数大范围、实时获取,该文基于遥感和GIS技术,采用BP神经网络算法,结合地面监测数据和Landsat 8遥感影像,分别建立了反演总磷、总氮、氨氮和COD(化学需氧量)4个水质参数的BP神经网络模型,并反演了密云水库2013-2018年非结冰期主要水质参数,分析了密云水库主要水质参数的年际变化特征、季节变化特征和空间分异特征。结果表明,(1)水质参数的Landsat 8敏感波段分别为:总氮为1、4波段,氨氮为1-7波段,总磷为1、3-7波段,COD为2-5波段。(2)密云水库主要水质参数在2013-2018年总体呈下降趋势,氨氮和COD为Ⅰ类水质,总磷为Ⅱ类水质,总氮为Ⅲ类水质。(3)4个水质参数指标春季最高、秋季次之、夏季最低,总氮、总磷、氨氮和COD的春季值分别是夏季值的1.08、1.36、1.6、1.45倍。(4)密云水库不同水质参数的空间差异性较大,总体来看,水库北部和东部的4个水质参数含量相对较高,这种分布与北部和东部村庄密集以及密云水库两大入库河流有关。综上所述,基于BP神经网络算法的密云水库水质反演研究是可行的,且得到了较为可信的研究结果,该研究可为密云水库水质管理与政策制定提供重要的科学依据。     

多溴联苯醚在啮齿类动物体内的代谢动力学研究进展

多溴联苯醚(PBDEs)是一类持久性有机污染物(POPs),其作为一种广泛使用的溴化阻燃剂在环境中普遍存在.PBDEs对生物体和人体存在内分泌干扰等毒性危害,正受到人们越来越多的关注.然而目前PBDEs对人体造成的影响都是由动物实验(主要是啮齿类动物)外推而得,因此研究不同的PBDEs同系物在啮齿类动物体内的代谢动力学...     

溶氧条件对美人蕉和风车草根系泌氧特征的影响

采用标准氧化染色法研究了美人蕉和风车草在水培畜禽废水自然、缺氧和好氧3种溶氧状态下根系径向泌氧（Radial oxygen loss,ROL）类型的变化和特征,采用显微镜明暗场观察了相应的根系横截面特征。结果发现美人蕉在3种溶氧状态下根系径向泌氧类型分别为均匀强泌氧、根尖强烈泌氧和不泌氧3种;风车草的径向泌氧类型则分别...     

Biochemical parameters of plants as indicators of air pollution

In the present study species like Mangifera indica, Linn., Cassia fistula, Linn., and Eucalyptus hybrid were exposed to different air pollution load for short duration (active biomonitoring). Variation in biochemical parameters like chlorophyll, protein, soluble sugar free amino acid, ascorbic acid, nitrate reductase, superoxide dismutase and peroxidase in the leaves were found to be pollution load dependent. These variations can be used as indicators of air pollution for early diagnosis of stress or as a marker for physiological damage to trees prior to the onset of visible injury symptoms. Just by analyzing these biochemical indicators air quality can also be assessed.     

Frequency of abnormal heavy metal blood levels in Wegener's granulomatosis

Previous studies suggested environmental exposures, including mercury (Hg) and lead (Pb), may be related to Wegener's granulomatosis. In this study, investigations were extended to include the measurement of heavy metals in blood samples from patients diagnosed with Wegener's. Diagnosis was confirmed by using the 1990 Classification Criteria for Wegener's granulomatosis established by the American College of Rheumatology (ACR). Using commercial lab testing, whole blood heavy metal screenings were obtained from patients, and results were then compared with validated subject self-report questionnaire estimates of exposure. Thirty-eight Wegener's patients were enrolled; 10 of the 38 exhibited abnormal lab values. In those 10 subjects 3 had elevated nickel (Ni), 7 with increased cobalt (Co), 3 with higher manganese, 1 with elevated copper, and 1 with increased Hg. Overall, the questionnaire results did not correlate with the blood heavy metal analysis. Approximately 26% of Wegener's subjects in this study displayed abnormal heavy metal levels. These findings are likely underestimates since blood levels are an insensitive means for assessing total body burden of heavy metals. From these preliminary studies it appears that elevated Co is a common finding in Wegener's patients but Ni and Hg were also found to be increased. The proportion of patients with abnormal heavy metal levels is more than expected by chance alone. In order to yield more definitive results, further analysis is needed with a larger data set, more controls and more sensitive measurements (hair, urine, or nail samples).     

Hematological responses of broiler chickens exposed to simulated crude petroleum emissions

Hematological responses of broiler chicken exposed to simulated crude petroleum emissions at varying distances over a period of 16 h daily were evaluated for 56 days in a poultry house. The burning of crude petroleum was simulated with a specially designed burner. The measured distances were 4, 8, or 12 m from the flame point. Control birds were located in a separate poultry building without the flame treatment. Gaseous emissions from the burning crude oil were monitored. Proprietory broiler starter and finisher diets were fed ad libitum. Blood samples were taken at the fourth and eighth weeks for hematological assay from each treatment. The hematological parameters assayed were hemoglobin (Hb), packed cell volume (PCV), white blood cells (WBC), neutrophils, and lymphocytes. Results indicated that the treatment did not significantly affect the Hb, PCV, and WBC constituents. Neutrophils significantly decreased while lymphocytes increased. The age of birds significantly increased Hb, PCV, and WBC levels in the blood.     

紫花芒果NPKCaMg叶片诊断的DRIS标准初步研究

按诊断与推荐综合系统（DRIS）标准建立的常规方法.通过比较低产和高产组叶片N、P、K、Ca、Mg养分含量以及两元素间的养分比和养分积,初步筛选出N／P、N／K、N／Ca、N／Mg、K／P、Ca/P、P／Mg、K／Ca.K／Mg和Ca／Mg作为DRIS参项,并初步提出紫花芒果DRIS诊断标准.     

Interference of three weed extracts on uptake of nutrient in three different varieties of paddy through radio tracer techniques

Interference of three dominant weed extracts viz., Ageratum conyzoides L., Melilotus indica All. and Parthenium hysterophorus L. were examined on seed germination, seedling growth, and nutrient uptake (32P and 65Zn) in three different varieties (PD-10, PD-12 and PB) of paddy (Oryza sativa L.). Among the three different varieties irrespective of weed extracts, PD-10 and PD-12 were resistant and PB was susceptible in terms of seed germination, radicle length and plumule dry weight; and PD-12 and PB were resistant and susceptible, respectively, in terms of plumule length and total seedling dry weight. A. conyzoides caused maximum reduction in seed germination and M. indica in seedling growth in different varieties of paddy. The weed extracts interfered in uptake of both 32P and 65Zn and there was a gradual decrease in uptake of both nutrients with increasing concentration of extracts in both root and shoot. The uptake of 32P and 65Zn was more inhibitory with the extracts of A. conyzoides and M. indica, respectively in different varieties. The inhibition in seed germination, seedling growth and nutrient uptake may be due to the presence of phenolics and other secondary metabolities. The phenolics such as gallic, vanillic, protocatechuic and p-hydroxybenzoic acids were identified from these weed extracts.     

干旱胁迫和复水对梨幼树生理特性的影响

为了解植物干旱生理适应机制和恢复机制,以梨品种‘翠冠’和‘黄冠’幼树为试材,研究土壤干旱胁迫及复水条件下叶片光合参数、叶片相对含水量、叶片质膜透性、超氧化物歧化酶活性及脯氨酸含量的变化特性.结果显示:1)随着干旱胁迫的加剧,两品种的叶片净光合速率、气孔导度和蒸腾速率均呈下降趋势;‘翠冠’叶片胞间CO2浓度呈先降后升的趋势,而‘黄冠’呈持续下降趋势,但‘黄冠’光合作用的4项指标明显高于‘翠冠’;复水后,两品种的光合指标恢复显著,但均未超过对照水平.2)干旱胁迫引起两品种的叶片相对含水量急剧下降,叶片质膜透性和脯氨酸含量显著升高,超氧化物歧化酶活性呈先升后降趋势;复水后,两品种的4项指标不同程度地得以恢复,但大部分指标没有恢复到对照水平,其中‘黄冠’各项指标在复水前后的变化幅度比‘翠冠’更小.综合分析表明,‘翠冠’和‘黄冠’对干旱胁迫的响应存在差异,‘黄冠’对干旱逆境具有更强的适应能力.     

Uncertainty analysis of a pharmacokinetic modeling for inorganic arsenic

This paper presents an uncertainty and sensitivity analysis of a pharmacokinetic modeling of inorganic arsenic deposition in rodents for a short‐term exposure. Efforts to develop the pharmacokinetic model are directed towards predicting the kinetic behavior of inorganic arsenic in the body, including tissue and blood concentrations, and especially, the urinary excretion of arsenic and its methylated metabolites. However, the use of the model raises an important question when fixed values of model parameters are used: how is the uncertainty in the model prediction based on the collective uncertainties in the model inputs? This study focuses on an “epistemic”; uncertainty in order to handle this problem. In this case, the uncertainty refers to an input that has a single value which cannot be known with precision due to a lack of knowledge about items or its measurement. The combination of the pharmacokinetic model and the uncertainty analysis would help understand the uncertainties in risk assessment associated with inorganic arsenic.     

Toxic metals status in human blood and breast milk samples in an integrated steel plant environment in Central India

Owing to its unique nutritional and immunological characteristics, human milk is the most important food source for infants. Breast milk can, however, also be a pathway of maternal excretion of toxic elements. Selected toxic elements (As, Pb, Mn,a Hg and Cd) were determined in human breast milk and blood samples obtained from 120 subjects related to an integrated steel plant environment located in central India. Samples of breast milk and blood from subjects living outside the steel plant environment were also analyzed for comparative study. Higher levels of these toxic elements were found in blood samples as compared to breast milk samples. Plant workers showed the higher presence of these metals in their breast milk and blood samples compared to the residents of the area and the subjects living outside the industrial environment, respectively. Mn, Pb and Hg have shown a higher tendency to associate with blood and breast milk than As and Cd. The order of occurrence of these metals in blood and milk samples thus found is Mn > Pb > Hg > As > Cd.     

Interaction effects of lead on bioavailability and pharmacokinetics of arsenic in the rat

Arsenic (As) and lead (Pb) are common contaminants found in mine waste materials. For an evidence-based risk assessment, it is important to better understand the potential interaction of mixed contaminants; and this interaction study was investigated in an in vivo rat model. Following co-administration of a fixed dose of As^V as in sodium arsenate and different doses of Pb as lead acetate to Sprague–Dawley rats, blood arsenic concentration and bioavailability decreased. A decrease in As blood concentration when lead was co-administered was observed with increasing lead doses. Pharmacokinetic parameters for As in the blood showed faster absorption and elimination of this metalloid in the presence of Pb. The elimination half-life of As decreased from 67 days in As solo group to 27–30 with doses of Pb. Bioavailability of As was also decreased by 30–43 % in the presence of Pb. Decreased urinary excretion of Pb and tissue accumulation were also observed. It indicates lower absorption of As when co-administered with Pb. A probable explanation for these findings is that As co-administration with Pb could have resulted in the formation of less soluble lead arsenate. However, such an interaction between As and Pb could only explain about one-third of the variation when real mine waste materials containing both of these elements were administered to rats. This suggests that other effects from physical and chemical parameters could contribute to the bioavailability of arsenic in complex real environmental samples.     

Cryptic herbivores mediate the strength and form of ungulate impacts on a long-lived savanna tree

Plant populations are regulated by a diverse array of herbivores that impose demographic filters throughout their life cycle. Few studies, however, simultaneously quantify the impacts of multiple herbivore guilds on the lifetime performance or population growth rate of plants. In African savannas, large ungulates (such as elephants) are widely regarded as important drivers of woody plant population dynamics, while the potential impacts of smaller, more cryptic herbivores (such as rodents) have largely been ignored. We combined a large-scale ungulate exclusion experiment with a five-year manipulation of rodent densities to quantify the impacts of three herbivore guilds (wild ungulates, domestic cattle, and rodents) on all life stages of a widespread savanna tree. We utilized demographic modeling to reveal the overall role of each guild in regulating tree population dynamics, and to elucidate the importance of different demographic hurdles in driving population growth under contrasting consumer communities. We found that wild ungulates dramatically reduced population growth, shifting the population trajectory from increase to decline, but that the mechanisms driving these effects were strongly mediated by rodents. The impact of wild ungulates on population growth was predominantly driven by their negative effect on tree reproduction when rodents were excluded, and on adult tree survival when rodents were present. By limiting seedling survival, rodents also reduced population growth; however, this effect was strongly dampened where wild ungulates were present. We suggest that these complex interactions between disparate consumer guilds can have important consequences for the population demography of long-lived species, and that the effects of a single consumer group are often likely to vary dramatically depending on the larger community in which interactions are embedded.     

Effects of gasoline engine emissions on health status of auto rickshaw drivers at DIR (L) Khyber Pukhtunkhwa

A total of 50 blood samples were collected from auto rickshaw drivers who were exposed to environmental gasoline in different sites of Dir (L), Khyber Pukhtunkhwa, Pakistan, in July and August, 2009. Control group was selected among the individuals who were not regularly exposed to gasoline emissions. The samples were analyzed for calcium, cholesterol, glucose, phosphorus, potassium, and triglycerides levels. A significant increase was found in the blood levels of calcium, glucose, phosphorus, and triglycerides. A significant decrease was detected in the blood levels of potassium without any significant effect on the blood levels of cholesterol and magnesium.     

Effect of barn ventilation on blood gas status and some physiological traits of dairy cows

Twenty Holstein friesian and Brown swiss cows were used to investigate the effect of insufficient in barn ventilation on blood gas status and some physiological traits of the cows. Animals were kept in mechanically ventilated barn in stall barn (I); and the ventilation funnels of the barn were closed to simulate traditional habits of the region's breeders (II); then cows were transfered open-shed barn (III). For each experimental of 10 days period, respiration and pulse rates and blood gas of animals were measured. Temperature, relative humidity, CO2 and NH3 concentrations were recorded in each barns. In mechanically ventilated barn, climatic and atmospheric gas was in normal ranges for the cows but in unventilated barn they were at the upper levels. In experiment II, blood pH was decreased without pCO2 change. The highest blood pO2 and HCO3(-) levels were found when the animals were kept in open-shed barn (III). Measured parameters were not influenced by breed of the cows. Blood pH, pO2 HCO3(-), respiration and pulse rates of the cows were significantly affected by barn types (p < 0.05 and p < 0.01). Respiration and pulse rates were higher in inadequate (II) barn conditions than those of open-shed. Higher levels of gases, especially carbon dioxide, in the unventilated barn significantly influenced biological parameters of cows. It is concluded that poor ventilation caused considerable changes in physiologic parameters of the cows and can potentially affect animal health and production.     

Toxic responses of different organs following occupational exposure to sub-threshold limit value levels of paving asphalt fumes

The main purpose of this study was to ascertain whether occupational exposure to asphalt fumes, under normal working conditions, is associated with any hepatotoxic, nephrotoxic, or hematotoxic response. This was a cross-sectional study in which 210 subjects (80 exposed and 130 reference subjects) were investigated. Using standard methods, atmospheric concentrations of total particulate and benzene-soluble fractions of asphalt fumes were measured. Additionally, urine and blood samples were taken from subjects for complete blood count, white blood cell differential test, urinalysis, and routine biochemical tests of kidney and liver function. Both groups were similar as far as their demographic variables and smoking habits were concerned. The levels of exposure to total particulate and benzene-soluble fractions were estimated to be 0.9?±?0.2 and 0.32?±?0.09 mg m^?3, respectively (mean?±?SD), both of which being lower than the existing threshold limit values. Statistically, significant associations between exposure to asphalt fumes and changes in most liver and kidney function tests and complete blood count parameters provided circumstantial evidence in favor of the notion that exposure to sub-threshold limit value levels of total particulate and benzene-soluble fractions is associated with early liver and kidney dysfunction as well as hematological disorders.