大口黑鲈PACAP基因SNPs的筛选及其与生长性状的关联分析

垂体腺苷酸环化激酶多肽(pituitary adenylate cyclase-activating polypeptide,PACAP)是一种能够促进生长激素、促性腺激素和催乳素分泌的多效激素,属于胰高血糖素/分泌肽家族的成员.为探索PACAP基因多态性对大口黑鲈(icropterus salmoides)生长性状的影响,本研究采用直接测序的方法在PACAP基因上检测到一个单核苷酸多态性(single nucleotide polymorphism,SNP)位点:A-2282C,基因型检测共发现3种基因型:AA、AC和CC,其基因型频率分别为0.034、0.645和0.321,A等位基因频率为0.356 3,C等位基因频率为0.643 7.随机选取同批繁殖、同塘养殖的327尾大口黑鲈用Snapshot方法进行SNPs位点检测和分型,构建最小二乘分析模型,分析基因型与生长性状的相关性.X2检测结果显示,哈温-平衡常数为0.061 5,即该位点在所检测大口黑鲈群体中基本处于Hardy-Weinberg平衡状态,有效等位基因数(Ne)为1.846 5,期望杂合度(Ho)和观测杂合度(He)分别为0.540 9和0.644 2.方差分析结果显示,AC基因型群体的平均体质量、体高和全长相对于AA基因型群体分别增长了30.6％、10.7％和8.3％,相对于CC基因型群体分别增长了10.5％、4.7％和2.7％;且AC基因型群体在体质量、体高和全长上显著高于AA和CC基因型群体(P＜0.05).另外,虽然AA基因型群体的平均体质量、体高和全长相对于CC基因型群体分别增长了18.1％、5.8％和5.4％,但AA型群体和CC群体在各生长性状上没有显著差异(P＞0.05).该位点可能是影响大口黑鲈生长性状的的主效数量性状核苷酸(quantitative trait nucleotides,QTN)或与之紧密连锁,可作为大口黑鲈选育的候选分子标记.     

加州鲈卵泡抑素cDNA的克隆、分析和原核表达

卵泡抑素是TGF-β超家族中一些成员的抑制蛋白，具有促肌肉生长的作用。采用RT-PCR和RACE技术从加州鲈成鱼卵巢总RNA中扩增得到卵泡抑素cDNA，序列分析结果表明，加州鲈卵泡抑素cDNA全长1444bp，包括开放阅读框966bp，5¢非编码区82bp，3¢非编码区359bp。该基因编码321个氨基酸，其中信号肽31个氨基酸，成熟肽290个氨基酸，成熟蛋白由四个功能区组成，分别为：N-domain、Domain Ⅰ、Domain Ⅱ和Domain Ⅲ，其中N-domain具有与TGF-β超家族中一些成员特异性结合的结构，可抑制这些蛋白发挥作用。将加州鲈卵泡抑素氨基酸序列与红鳍东方鲀、草鱼、斑马鱼、大西洋鲑和斑点叉尾鮰比较，同源性分别为97％、89％、88％、88％和70％，其中N-domain氨基酸序列的保守性更高一些，与红鳍东方鲀、草鱼、斑马鱼、大西洋鲑、斑点叉尾鮰、非洲爪蟾、人、猪、大鼠、鸡的相比较，同源性为75%～100％。为获得重组卵泡抑素蛋白，将成熟肽cDNA插入表达载体pET-32a(+)，转化大肠杆菌，IPTG诱导表达，SDS-PAGE检测，结果检测到一分子量约52kD的特异蛋白带，与预期大小一致，Western blot检测到表达产物表明成功获得了卵泡抑素的融合蛋白。加州鲈卵泡抑素cDNA序列和重组蛋白的获得为进一步研究鱼类卵泡抑素的促肌肉生长奠定了基础。     

Predictive Model for Mercury Accumulation in Carp (Cyprinus Carpio) of Reservoirs in China

Construction of hydroelectric reservoirs in a certain large watershed of China has led to a marked rise in mercury concentration in fish. Correlation analysis and stepwise regression of R values (ratio of mercury concentration in carp from 12 reservoirs and mercury concentration in carp from rivers which feed into the reservoirs) and various hydrologic parameters demonstrate that the ratio of catchment area and runoff is the crucial determining factor. Other determining factors are the ratio of flooding area of land and reservoir area of dead storage capacity, and the reciprocal of reservoir area. On this basis, the predictive models of mercury accumulation in carp after reservoir construction, with one and two parameter, respectively, were obtained. The predictive models were found to be of high precision.     

Mercury in soils,sediments, and clams from a North Carolina peatland

Mercury concentrations were measured in samples of peat soils, sediments and clams (Rangia cuneata) from a peatland region of the Albemarle-Panlico Peninsula of North Carolina. Total Hg concentrations in peat cores ranged from 40 to 193 ng g^?1 (dw); no depth-related trends were noted. Mercury concentrations in surface sediments from canals draining the peatlands and from the Pungo River that receives this drainage ranged from 8 to 20 ng g^?1 (dw). Selective extractions of these peat and sediment samples revealed that the bulk of the Hg was associated with organic matter-associated fractions (particularly humic/fulvic acid bound and organic-sulfide bound fractions). No Hg was detected in the relatively mobile and bioavailable water-soluble or ion-exchangeable fractions. Total Hg concentrations in the soft tissues of clams from the Pungo River ranged from 25 to 32 ng g^?1 (ww). No concentrations of methyl Hg above the detection limit of a 25 ng g^?1 were measured in soils, sediments, or clams. These data indicate that Hg concentrations in this region are at the low end of the distribution of levels reported for uncontaminated systems and that mining of these peatlands is unlikely to significantly elevate Hg concentrations in the receiving estuarine system.     

Subsurface leachate migration from a reject coal pile in South Carolina

Transport of contaminants from coal storage areas through the rooting zone has the potential to negatively affect shallow ground water and terrestrial vegetation. Reject coal piles represent a worst-case scenario for contamination from coal storage areas because of the long residence time of the coal. Preliminary hydrologic data were collected from an area of stressed vegetation adjacent to an inactive ash basin and reject coal pile in South Carolina. The water table is near the surface (< 60 cm) in this wetland area and water movement is primarily to the west, toward the Savannah River. Acid leachate migration from the reject coal pile has contaminated the water-table aquifer with sulfate (up to 22 200 mg L^?1) and metals (Fe to 9560 mg L^?1) Al to 1110 mg L^?1) A shallow plume of contaminated ground water parallels the reject coal pile and is elongated in the direction of ground-water movement. The plume is migrating westward at a calculated velocity range of 6.3 to 10.4 m yr^?1. Leachate migration from the reject coal has produced a highly acidic (pH down to 2.2) and highly saline (EC to 11.8 dS m^?1) rooting zone and is most likely responsible for the stressed vegetation in the study area.     

Responses of Young Trees (Five Species in a Chamber Exposure) to Near-Ambient Ozone Concentrations

This investigation is intended to add to the quantitative information about the sensitivity of European deciduous tree species to environmentally realistic ozone (O₃) exposure in respect to the established critical level of an AOT40 of 10 ppm.h (6-month growing season, daylight hours). Cuttings (without leaves) of Fagus sylvatica L., Sorbus aucuparia, L., Carpinus betulus L., Fraxinus excelsior L., and cuttings and seedlings of Prunus serotina Ehrh. were exposed during one growing season either to filtered air, to which 50 % of ambient O₃ concentration was added, or to 50 % + 30 ppb O3, resulting in a final AOT40 of 0.3 and 20.7 ppm.h, respectively. The foliage formed per tree varied between and within the species, but was not significantly modified by O₃, whereas the number of symptomatic leaves per tree significantly increased in the 50 % + 30 ppb O₃ regime. By mid July light-green spots appeared in the leaves (except C. betulus), which developed into stippling (F. excelsior), red (P. serotina) or necrotic spots by September. The CO₃-assimilation rate decreased more with increasing visual symptoms (earliest in 20- day-old leaves) than with age-dependent leaf discoloration in F. sylvatica, F. excelsior, and P. serotina (not in C. betulus). The dark-adapted photosystem II quantum yield (Fv/Fm) slightly declined with leaf age, but a considerable reduction became apparent in 107-day-old leaves with O₃-symptoms only. By late morning yield reduction in light-adapted leaves were exaggerated in such leaves from the 50 % + 30 ppb O₃ regime. The above mentioned responses were not reflected in significant changes of the net biomass production during the experiment. The critical level, therefore, is based on visual and functional symptoms rather than on production.     

Mercury Concentrations in Stream and River Water: An Analytical Framework Applied to Minnesota and Wisconsin (USA)

The total concentration of all mercuryspecies in water, [THg]_w, is a key water qualitymeasure. This paper proposes an analytical framework forthe analysis, interpretation and eventual projection ofstream (and river) [THg]_w. Mercury (Hg) isconceptualized as being distributed among four carriergroups in water: suspended mineral particles, particulateorganic carbon, dissolved organic carbon, and inorganiccomplexes and ions. The conceptual understanding is used asa statistical analytical framework and turned into aquantitative model for Minnesota and Wisconsin based on some1000 data cases from 18 streams (watershed area: 9 ha–115500km²). The resultant model yields a coefficient ofdetermination of 92% for [THg]_w of the fitting datasubset, or 94% for the evaluation subset. Its coefficientshave well defined physical meanings, and are generallyconsistent with independent field measurements from the sameregion or elsewhere. The model provides a comprehensive andquantitative view of the Hg contents of the carriers: thecontents increase with the proportion of watershed area aswetlands or as forests, rise drastically and then fallprecipitously during spring snowmelt, and otherwise peak inthe growing season and reach a minimum in the presence ofsnowpack. The model further reveals that dissolved Hg tendsto increase with emission-related wet sulfate depositionacross the data region.     

Geospatial Soil and Plant Tissue Analysis of Sericea Lespedeza (Lespedeza cuneata) Invasion around Lake Issaqueena,South Carolina

This study was conducted to determine the chemical composition of sericea lespedeza (Lespedeza cuneata) as well as soil and landscape characteristics that correlate with its invasion. Geographic Information Systems (GIS) and Light Detection and Ranging (LiDAR) were used to determine the pattern of invasion and to quantify landscape metrics. Sericea lespedeza was distributed on both sides of the lake in Pacolet and Madison soil map units (Fine, kaolinitic, thermic Typic Kanhapludults) on average slopes of 17.5%. It was common along roads and trails with a preferred mean canopy cover of <50%. Plant tissue analysis revealed statistically higher concentrations of macronutrients nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca) and sulfur (S) and selected micronutrients in leaves compared to stems and roots. Micronutrients copper (Cu), manganese (Mn) and iron (Fe) were significantly higher in stems and roots. Soil analysis results showed no statistical difference between control and invaded plots for measured soil chemistry parameters.     

Concentrations of trace elements in yellow perch (Perca flavescens) from six acidic lakes

Yellow perch (Perca flavescens) were collected from six small acidic lakes in northwestern New Jersey. Analyses of muscle tissue identified a pattern of increased concentrations of Hg in fish from the most acidic lakes; levels of Cd and Pb were greatly elevated in livers of specimens from two of the most acidic lakes. At one site, Sunfish Pond, positive correlations between fish size and Hg levels in muscle and Cd concentrations in livers were detected. In only one case did Hg concentrations in muscle tissue exceed the U.S. FDA action level of 1 μg g^?1 (wet wt).     

Mercury and selenium content in Bouri (Mugil cephalus)

This study was carried out to estimate the levels of total, organic, inorganic-Hg, total Se and the interaction between both elements in the muscle and other body organs of bouri (Mugil cephalus). The results showed that strong closeness of correlation between length of fish and each of. (a) total, inorganic, organic Hg, and total Se in muscle, (b) total and organic Hg in backbone, (c) total and inorganic Hg in viscera.     

Mercury and polychlorinated biphenyls in striped bass (Morons saxatilis) from two nova Scotia Rivers

Striped bass (Morone saxatilis) collected from the Annapolis and Shubenacadie Rivers in Nova Scotia, Canada, were analyzed for Hg in four tissues and for PCB's in two tissues. Average Hg concentrations in the muscle, liver, kidney, and gonad of 3.9 kg fish from Annapolis River were 0.77, 0.79, 0.26, and 0.07 μg g^?1, respectively, and the corresponding values for the much smaller, 1.5 kg, fish from the Shubenacadie River were 0.51, 0.27, 0.24, and 0.06 μg g^?1. The PCB concentrations in the muscle tissues of fish from Annapolis and Shubenacadie Rivers are 0.02 and 0.01 μg g^?1, respectively, while the concentrations in gonads are 1.4 and 0.04 μg g^?1 The observed lack of recruitment of striped bass in the Annapolis River may be related to high PCB concentrations in the gonad tissue.     

Estimation of Polychlorinated Biphenyl (PCB) Levels in Livers of the Otter (Lutra Lutra) from Concentrations in Scats and Fish

The decline of the European otter (Lutra lutra) seems to be related to environmental contamination especially with polychlorinated biphenyls (PCBs). Only a limited number of tissue samples from otters killed accidently as traffic victims or drowned in fishnets are available for residue analysis. Calculating the levels of PCBs in otter tissues from concentrations in fish and scats would be a very valuable tool to estimate potential risks for this endangered species. PCB levels measured in otter livers, scats and fish from a Middle European otter population were used to examine the suitability of mathematical models for calculating PCB concentrations in otter liver from fish concentrations and from scat levels. Our results suggest that the models and input parameters currently used to calculate PCB concentrations in otters to estimate risks do not predict mean concentrations in otter livers in our Middle European study area, giving lower concentrations than actually analysed in the tissues. Possible causes for the observed discrepancy between measured and calculated values are discussed.     

Interpretation of Mercury Concentrations in Eight Headwater Lakes in Kejimkujik National Park, (Nova Scotia, Canada) by Use of a Geographic Information System and Statistical Techniques

The concentration of mercury in eight headwater lakes in Kejimkujik National Park correlated positively with total organic carbon, total nitrogens, aluminum, iron and sodium andnegatively with pH and alkalinity (Gran). Annual average mercuryyield of the lakes correlated positively with basin area to lakesurface area ratio, and watershed areas underlain by granite bedrock and glacial deposits and negatively with greywacke bedrock. Principal component analysis indicated that first threecomponents account for 80% of the total variance in the data.The components were related to physiography and geology of the watershed, hardness of water, and atmospheric washouts of longrange transported acidic pollutants and dust particles. Mercuryin the lake waters was associated with the physiography and geology of the watershed. Total organic carbon, aluminum and iron were good predictors of mercury concentration in the lakewaters as were the basin area to lake surface area ratio, and basin areas underlain by granite bedrock, and Halifax slate forthe lake mercury yield. The results showed that transport of mercury from the watershed is a major source of mercury in thestudy lakes.     

Mercury (Hg) Transport in a High Arctic River in Northeast Greenland

In a warming climate, mercury (Hg) pathways in the Arctic can be expected to be affected. The Hg transport from the high arctic Zackenberg River Basin was assessed in 2009 in order to describe and estimate the mercury transported from land to the marine environment. A total of 95 water samples were acquired and filtered (0.4 ??m pore size), and Hg concentrations were determined in both the filtered water and in the sediment. A range of other elements were also measured in the water samples. Hg concentrations in the filtered water were in general highest in the beginning of the season when the water came mainly from melted snow. THg concentrations in the sediment were in general relatively constant or slightly decreasing until mid-August, where after the concentrations increased. A principal component analysis separated the samples into spring, summer and autumn samples indicating seasonal characteristics of the patterns of element concentrations. The total amount of Hg in the sediment transported was estimated to 2.6 kg. Approximately 60% of the sediment-transported Hg occurred during a 24-h flood in the beginning of August caused by a glacial lake outburst flood. The total amount of transported dissolved Hg was estimated to 46 g, and 13% of this transport occurred during the 24-h flood. If it is assumed that the Hg transport by Zackenberg River is representative for the general glacial rivers in East Greenland, the total Hg transport into the North Atlantic from Greenland alone is approximately 4.6 tons year^?1 with an estimated annual freshwater discharge of ??440 km³.     

Cesium-137 Concentrations in Sediments and Aquatic Plants from the Pinios River, Thessalia (Central Greece)

The levels of radioactive contamination by artificial radiocesium (¹³⁷Cs) were evaluated in sediments and the commonest species of water plants. Specimens were collected from a range of biotopes along the Pinios River and its tributaries, during the years 1998 and 2010. The ¹³⁷Cs concentrations within the above period clearly indicate that this radionuclide still decrease in the River Pinios. A marked decrease is also observed in comparison to our previous results in 1993. ¹³⁷Cs concentration activities in the sediment are higher than in the plant material. In general, roots showed greater ¹³⁷Cs concentration than leaves, while stems showed the lowest concentration. Significant differences in ¹³⁷Cs concentrations were found among different species growing under similar environmental conditions. ¹³⁷Cs content in collected aquatic plants was in the descending order: Ceratophyllum demersum L. > Myriophyllum spicatum L. > Paspalum pasalodes Scribner > Cladophora glomerata L. > Cyperus longus L. > Potamogeton nodosus Poiret. A comparison of the studied stations indicated that the southwest side of Thessalia plain, where the first two initial sampling stations of the Pinios River and the tributaries Enipeas and Kalentzis are situated, was highly contaminated. Low ¹³⁷Cs concentrations were observed in the Titarisios tributary, originated from the northeast part of Thessalia plain, behind Mt. Olympus and the last sampling stations of the Pinios River.     

Seasonal Changes of Magnetic Susceptibility in Sediments from Lake Zywiec (South Poland)

Lake Zywiec is a man-made lake constructed in 1965 on the Sola River, Beskidy Mountains (South Poland). The lake is the largest one in a flood control reservoir system known as the Sola Cascade. In May and September 1970, separated by a big flood event in July, the lake was sampled for rock magnetic, chemical and granulometric studies. In 85% of the September samples, susceptibility decreases by 10 to 40% compared to the value measured in May. Seasonal changes are also observed in the total Fe content and some heavy metals. A general decrease in Zn, Pb, Cd, Cu and Cr content during the summer season was observed in the whole lake. The content of other metals such as Mn and Ni increased in samples taken in September. The changes observed in the lake sediments could be only an accidental result of the flood or may indeed result from seasonal changes fostered by the flood effect.     

Seasonal variability in the Mercury speciation of Onondaga Lake (New York)

Dissolved and particulate Hg speciation was determined on four occasions in the Spring to Fall interval of 1989, at three depths of the water column of Onondaga Lake, New York; an urban system in which the sediments and fish flesh are contaminated with H_g. Species determined included total Hg (Hg_t), reactive (‘ionic’) Hg (Hg_i), monomethylmercury (CH₃HgX), elemental Hg (Hg°) and dimethylmercury (CH₃)₂Hg). Onondaga Lake was found to contain very high levels of Hg_t (2 to 25 ng L^?1 Hg), Hg_j (0.5 to 10 ng L^?1 Hg), and CH₃HgX (0.3 to 7 ng L^?1 Hg), which generally increased with depth in the lake. These concentrations represent a significant level of contamination, based upon comparisons with other polluted and pristine sites. Elemental Hg levels were typically about 0.05 ng L^?1 and (CH₃)₂Hg was near the limits of detection (?0.001 ng) L^?1 in most samples. The greatest CH₃HgX concentrations in the hypolimnion, as well as the largest gradients of both CH₃HgX and (Hg_t), were observed upon the first onset of stratification, in early summer. These concentrations did not become more pronounced, however, as stratification and H₂S levels in the hypolimnion increased throughout the summer. The very low concentrations of (CH₃)₂Hg in these MeHg and sulfide-rich waters calls into question the belief that CH₃HgX and H₂S will react to yield volatile dimethyl-mercury, which can then escape to the atmosphere by diffusion. Mercury speciation was highly dynamic, indicating active cycling within the lake, and an apparent sensitivity to changes in attendant Iimnological conditions that track the stratification cycle.     

青紫泥-水稻作物系统中汞污染的微生物学效应

选择长江三角洲地区代表性人为耕作土壤青紫泥为研究对象,通过网室盆栽试验研究了青紫泥-水稻作物系统中汞的微生物学效应。结果表明:水稻收获后,除土壤的代谢商随汞处理浓度的增加而增加外,不同汞处理后土壤微生物量碳、呼吸强度和微生物生物商均表现为在低浓度汞处理(≤1.5 mg/kg)时有促进作用,在高浓度汞处理(≥2 mg/kg)时则表现出抑制作用。综合来看,土壤微生物商是汞处理后比较敏感的微生物学指标。此外,种植水稻后,随处理水平的增加,与对照相比,青紫泥各汞处理土壤微生物群落的代谢剖面AWCD值均降低;青紫泥中各处理的AWCD值均随培养时间的增加而增强,且呈S型指数增长模式;青紫泥中各处理的Simpson指数和McIntosh指数均比对照低,其中Simpson指数和外加汞浓度之间存在显著的相关性,可作为反映青紫泥微生物群落结构受汞污染程度的有效指标。     

南亚热带5种典型人工林凋落物水文效应

以广西国有高峰林场的5种不同人工林(马尾松林、杉木林、桉树林、米老排林、红锥林)为研究对象,结合野外调查和室内浸水法,对各人工林凋落物层的水文效应进行定量分析。结果表明:(1)5种林分凋落物蓄积量范围在1.96～9.05 t/hm~2,大小顺序为红锥林杉木林马尾松林桉树林米老排林。(2)5种林分凋落物中,杉木林最大持水量最大,为14.23 t/hm~2,马尾松林最小,为6.26 t/hm~2;米老排林凋落物最大持水率最大,为577.98%,红锥林最小,为135.46%。(3)杉木林凋落物的有效拦蓄量最大,为10.18 t/hm~2,马尾松林最小,为4.07 t/hm~2;米老排林凋落物有效拦蓄率最大,为463.35%,红锥林最小,为92.38%。(4)回归分析表明,凋落物持水量与浸水时间的关系符合对数函数关系(Q=aln t+b(R~20.773)),凋落物吸水速率和浸水时间的关系符合幂函数关系(V=kt~n(R~20.997))。持水过程中,各林分凋落物均表现为在1 h内持水量迅速增加,1 h后增加速度变慢,在10～12 h之后,吸水基本停止。综上,杉木林、米老排林凋落物层水源涵养功能较强。