湖北省钉螺分布现状的地理特征分析

湖北省是我国血吸虫病疫情最严重的区域之一，是我国血防工作的重点区域。近些年来，虽然湖北省的血防工作取得了显著成就，但疫情仍时有发生，实现血吸虫病传播阻断的目标还有大量工作要做。由于钉螺是血吸虫病传播的唯一中间环节，灭螺、控螺就成为血防工作最重要、最有效的途径之一。鉴于此，对湖北省近期钉螺的地理分布进行了详细的制图与空间分析，对于确定灭螺、控螺的重点区域具有明显的指示意义。首先收集整理了湖北省血吸虫年报及各县市的查灭螺资料，并利用软件ArcGIS软件将钉螺螺情数据导入数据库，建立湖北省钉螺地理信息基础数据库，绘制了钉螺空间分布图，然后对钉螺分布的空间特征进行了分析。主要结论如下：省内钉螺及钉螺易感地带沿长江中游、汉江两岸以及与两江相通的湖泊洪泛区分布，并呈明显的粗带状；各流行区类型（湖沼垸外亚型、湖沼垸内亚型和山丘型类型）钉螺地理空间分布具有明显的区域差异；江湖洲滩为钉螺主要孳生环境，总体沿两江呈不连续窄带状分布，沟港环境钉螺分布范围广而离散     

博落回植物与肥料复合的杀螺效应及对水稻生长影响

探索一种杀螺施肥双效作用的新型杀螺剂。将博落回植物粉末分别与氮、磷、钾肥复合制成植物3种单肥复合杀螺剂(简称MPF)，与3种肥料混合配成植物混合肥复合杀螺剂(简称MCF)。采用浸杀法进行杀螺试验, 同时检验该复合杀螺剂对水稻萌发及生长的影响。结果显示，3种MPF(博落回植物分别与氮、磷、钾肥复合杀螺剂)处理钉螺，48 h钉螺死亡率分别为100%、533%、667%；作用于水稻，能明显促进种子萌发和幼苗生长，如3种MPF使水稻种子萌发率分别为100%、80%和53%，分别比对照（40%）提高了60%、40%和13%；水稻幼苗分别增长了1268%、707%和605%。MCF随处理浓度增加及处理时间延长，钉螺死亡率上升，较低浓度（200 mg/L）处理48 h 和72 h,钉螺死亡率分别为733%和867%；较高浓度（400 mg/L）复合处理48 h和72 h，钉螺死亡率分别为833%、100%。然而，低浓度（200 mg/L）MCF对水稻萌发和生长有促进作用，如水稻幼苗比对照增长了876%，但高浓度（400 mg/L）则有一定抑制作用。因此，MPF对钉螺具有较好的杀螺活性，同时能促进水稻萌发和生长，其中植物氮肥复合杀螺剂效果最佳；MCF对钉螺均有杀螺活性，但低浓度对水稻有促进作用，而高浓度则有抑制作用     

江汉平原土地利用对钉螺分布的影响研究

分析了江汉平原2009年易于钉螺孳生的3种土地利用类型（滩地、河渠和水田）比例与钉螺密度的关系。首先，在ERDAS9.2和ENVI4.7软件中对江汉平原2009年的Landsat5TM遥感影像进行了预处理。在已有的多期土地利用数据的基础上，借助eCognition软件利用向量相似度指标来提取土地利用变化区域，结合目视解译经验并运用遥感指标通过建立规则集对变化区域进行分类，将变化区域的分类结果更新2000年数据，得到了该区域2009年的土地利用数据。接下来，整理了江汉平原2009年螺情资料并计算出村级钉螺平均密度，绘制了2009年钉螺分布图。将绘制的钉螺分布图与土地利用分类图叠置分析，并结合收集的螺情数据确定了钉螺易于孳生的3种土地利用类型，分别为滩地、河渠和水田。最后，将钉螺密度与这3种土地利用比例进行线性回归分析。研究结果表明，钉螺密度与这三种土地利用类型比例存在线性回归关系，模型精度为R2=0857。该结论对通过遥感影像来估算钉螺密度具有指导意义，另外也可以为湖北省提出合理用地和灭螺并重的土地利用模式提供一定的科学参考     

灭螺药氯硝柳胺急性暴露对斑马鱼胚胎/幼鱼代谢能力的影响

氯硝柳胺（Niclosamide, NIC）是我国目前使用最久，也是使用量最多的化学灭螺药物，其带来的环境问题和生物安全问题逐渐引起人们重视。我们前期研究证实，NIC急性暴露会干扰斑马鱼幼鱼脂代谢途径，该研究在此基础上，进一步深入研究环境相关浓度NIC急性暴露对胚胎/幼鱼代谢水平的干扰效应。将受精2 h内的健康斑马鱼胚胎暴露于环境相关浓度的NIC（浓度依次为0，5，10，20和40 μg/L）至120 h。结果表明，和对照组相比，40 μg/L NIC暴露会显著改变幼鱼体内代谢产物，如葡萄糖和乳酸含量（P < 0.05 和P < 0.05）；另外，NIC暴露还会显著抑制幼鱼体内柠檬酸合成酶（CS）活力，而乳酸脱氢酶（LDH）活力被显著增强（P < 0.05 和P < 0.05）。代谢相关过氧化物酶体增值剂激活受体（PPAR）家族中的两个基因，pparα和pparγ，在NIC暴露组中其mRNA的相对表达水平都被显著上调（P < 0.05 和P < 0.05）。上述结果说明，环境相关浓度的NIC急性暴露会对早期胚胎的发育及幼鱼体内代谢水平造成干扰，表现为改变体内代谢相关基因的表达水平，并对代谢相关酶的活力和代谢产物的含量造成影响。     

1980年来湖北省钉螺分布区域及其数量的消长分析

目前对钉螺分布及消长的研究主要是短期的、文字描述性的、数字和曲线图表示的,通过这些方式可以呈现出某个地域范围的钉螺消长的总体趋势。但是,若要呈现出以行政村为单位的各个地区钉螺分布及消长的长期变化,仅仅用文字和曲线图是不够的,而是需要用更复杂的方式,才能呈现各个行政村的钉螺消长时空分布情况。地理信息系统(GIS)可以通过地图清晰显示出这些复杂的动态变化。利用湖北省钉螺的螺情村级统计年报数据,以湖北省村级行政区划图为基本空间制图单元,利用ArcGIS软件的逻辑运算和统计功能,分析了各个村级行政区从1980~2009年每间隔5 a的钉螺分布的区域及面积大小,以及钉螺数量的消长情况,并用GIS软件详细制图,获得各个村级行政区的钉螺数量的消长变化情况。根据钉螺消长情况,将所有行政村分为八类,可以识别出钉螺反复出现和难以消灭的地区,并且在地图中清晰地呈现出来。针对各个钉螺消长类型,结合自然地理、人为治理途径等情况进行相关分析,总结出湖北省各地区钉螺消长类型分异的原因,这将有利于制定县市甚至细化到村级单位的钉螺防控计划,也有利于辨识过去30 a来钉螺分布及其数量消长的区域以及灭螺的效果,对今后血吸虫的防治工作有重要指导意义。     

运用证据权重与确定性系数合成模型进行钉螺-环境因子的空间关系研究

钉螺是血吸虫唯一中间宿主,研究钉螺与孳生环境因子的空间关系对采取有效的查螺、灭螺措施有重要的科学和社会价值。以鄱阳湖恒湖农场茶叶港草洲为研究对象,应用证据权重法与确定性系数法合成模型研究植物南荻、苔草、藜蒿、土壤温度、土壤湿度、导电率、海拔高程7个证据因子与"钉螺出现与否"的空间关系。结果表明:研究区内一定范围内高程的增加易于钉螺孳生;钉螺在湿度相对较大(大于0.35%(m~3/m~3))的环境中分布较少;苔草丰度过大(高于4 368 cm~3/m2)过小(低于1 457 cm~3/m2)都不利于钉螺孳生;钉螺较易孳生在南荻丰度较大(高于2 745 cm~3/m2)的区域;电导率较高(高于0.07 m S/cm)区域钉螺较少;土壤温度在16~20℃范围利于钉螺孳生。在模型预测结果图中,占研究区总面积13.7%的极高易发区的较小范围内预测到82%的钉螺空间分布,评价曲线的曲线下面积高达88.7%,说明模型的预测成功率很高,表明该模型适合研究区域钉螺孳生与其影响因子之间的空间关系。     

江苏阳澄湖螺类群落的空间分布格局

2008年1月～2009年10月对江苏阳澄湖螺类群落结构进行了季节调查研究。共采集到螺类4科5属6种，优势种为铜锈环棱螺，次优种为长角涵螺。阳澄湖螺类平均密度为220±47 ind./m2，平均生物量为2331±469 g/m2，螺类密度和生物量在年际和季节间均无明显差异，但群落结构存在显著的空间变化，密度在东湖区和中华绒螯蟹围网养殖区较大、西湖区最小，生物量围网养殖区最高、西湖区最低；铜锈环棱螺密度围网养殖区最高、西湖区最低，长角涵螺密度东湖区最高、围网养殖区次之、入湖河流及其它湖区极低。中华绒螯蟹养殖未导致围网养殖区螺类数量下降，螺类（主要是铜锈环棱螺）的投放可能是该区螺类密度、生物量及铜锈环棱螺所占比例较高的主要原因之一。逐步回归分析表明，水深是影响螺类群落整体密度和生物量空间分布差异的主要因子；典型对应分析（CCA）表明，铜锈环棱螺主要分布在叶绿素a较高的水域，而长角涵螺和纹沼螺则主要分布在透明度较大的地方     

重大工程对血吸虫病流行区扩散的潜在影响

归纳了我国三峡工程、退田还湖及南水北调等一系列重大工程所引起水位、植被及微生物气候等生态环境要素变化对血吸虫唯一中间宿主钉螺分布的影响，分析了血吸虫病疫区的变化趋势和钉螺北移的可能性。研究表明三大工程实施区存在血吸虫病流行的潜在危险，加之我国新增有螺面积明显增多，血吸虫病疫情呈此消彼涨态势，血防工作形势依然严峻。当前国内有关工程对生态环境及血吸虫病影响的研究，主要为局部的调查报告及在现有基础上预测工程对血吸虫病流行的可能影响，生态环境变化还需要时间来验证。因此，建议应用GIS和RS等技术，监测分析生态环境变化，并进一步研究社会经济变动与血吸虫病传播的关系，同时，工程实施地区应提高疫区群众自我防护意识和能力，并结合林业、水利工程建设对有螺环境进行改造.     

石首市抑螺防病林空间布局优化研究

20世纪80年代以来，我国血吸虫疫区的林业血防生态工程建设已取得显著成效，但局部地区的抑螺防病林仍存在空间布局不完善、螺情反复出现的现象。在石首市钉螺孳生环境适宜性分析的基础上，采用层次分析法对钉螺孳生地的风险等级进行了评价，并通过抑螺防病林宜林地和更新区分布研究确定了抑螺防病林的空间布局优化区，以期为完善抑螺防病林建设工程布局提供依据。研究结果表明：石首市钉螺孳生高风险区主要分布在长江及其支流沿线、沟渠、塘堰和滩涂，占研究区总面积的874%。钉螺孳生中风险区主要分布在长江垸内，占总面积的2377%。钉螺孳生低风险区主要分布在大型湖泊、长江等永久水体以及城镇用地周围，占总面积的6749%。石首市抑螺防病林以中幼林为主，面积占抑螺防病林总面积的8047%。成熟林和过熟林（更新区）总面积4 51251 hm2，占抑螺防病林总面积的1405%。另有宜林地2 82336 hm2，石首市抑螺防病林优化区总面积为7 33586 hm2。其中，2395%的优化区分布在钉螺孳生的高风险区，2322%的优化区分布在钉螺孳生的中风险区，5283%的优化区分布在钉螺孳生的低风险区，是未来几年开展抑螺防病林建设的重点区域     

平原湖区钉螺分异规律及孳生环境特征研究——以湖北公安县为例

以血吸虫病典型流行区湖北省公安县为研究区，以行政村为基本研究单元，通过空间自相关和分组分析方法探究公安县钉螺空间分异规律，进而运用逐步回归、地理加权回归和地理探测器模型探讨公安县钉螺分布影响因素及其交互作用。结果如下：（1）公安县钉螺密度具有较强的空间集聚特性，形成2个较大的热点集聚区；综合考虑公安县钉螺密度水平和空间连接性，将公安县划分为高、中、低3个钉螺密度区。（2）人口密度、水网密度、水田比例、春季NDVI和秋季NDVI是公安县村级尺度钉螺密度主要影响因素，其影响效应具有空间异质性。（3）从整个研究区来看，两因子交互作用均产生非线性增强（NE），即两因子交互作用于钉螺密度时要比单因子具有更大的影响力。从钉螺密度类型分区来看，高、中钉螺密度区各因子之间的交互作用类型有双因子增强型（BE）和非线性增强型（NE）；而低钉螺密度区各因子交互作用均产生非线性增强作用。研究结果可为江汉平原乃至全省钉螺及血吸虫病防控工作提供决策支持。     

Rates of energy and phosphorus metabolism in Littorina snails (gastropoda)

Energy metabolism and phosphorus excretion were studied in Littorina littorea and L. saxatilis snails from the White Sea. Some elemental components of the body were determined quantitatively, and the rates of oxygen consumption and phosphorus excretion were estimated. All parameters were calculated relative to dry body weight (mg). Daily expenditures for energy metabolism in Littorina spp. averaged 3.6 ± 1.1%, and those for phosphorus metabolism were approximately four times lower (about 1%), with the total phosphorus content averaging 0.8% dry body weight. The atomic ratio of consumed oxygen to excreted phosphorus for both species averaged O: P = 1164 ± 140.     

The use of the oxidative stress responses as biomarkers in Nile tilapia (Oreochromis niloticus) exposed to in vivo cadmium contamination

Water contaminants have a high potential risk for the health of populations. Protection from toxic effects of environmental water pollutants primarily involves considering the mechanism of low level toxicity and likely biological effects in organisms who live in these polluted waters. The biomarkers assessment of oxidative stress and metabolic alterations to cadmium exposure were evaluated in Nile tilapia, Oreochromis niloticus. The fish were exposed to 0.35, 0.75, 1.5, and 3.0 mg/l concentrations of Cd2+ (CdCl2) in water for 60 days. Fish that survived cadmium exposure showed a metabolic shift and a compensatory development for maintenance of the body weight gain. We observed a decreased glycogen content and decreased glucose uptake in white muscle. Lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities were also decreased, indicating that the glycolytic capacity was decreased in this tissue. No alterations were observed in total protein content in white muscle due to cadmium exposure suggesting a metabolic shift of carbohydrate metabolism to maintenance of the muscle protein reserve. There was an increase in glucose uptake, CK increased activity, and a clear increase of LDH activity in red muscle of fish with cadmium exposure. Since no alterations were observed in lipoperoxide concentration, while antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were changed in the liver and the red and white muscle of fish with cadmium exposure, we can conclude that oxygen free radicals are produced as a mediator of cadmium toxicity. Resistance development is related with increased activities of antioxidant enzymes, which were important in the protection against cadmium damage, inhibiting lipoperoxide formation.     

Modelling chronic exposure to contaminated soil: a toxicokinetic approach with the terrestrial snail Helix aspersa

To enlarge the possibilities of using organisms of the soil fauna to assess the bioaccumulative potential of chemicals, the kinetic of soil cadmium (Cd) transfer to the terrestrial gastropod Helix aspersa was investigated under laboratory conditions during a long-term experiment (6 months). During the exposure phase (3 months), juvenile snails were subjected to three different concentrations of Cd spiked in artificial ISO soil (ISO 0, 20 and 100 mg Cd kg(-1)) and to a field soil (ME4) industrially contaminated by 20 mg Cd kg (-1). For both soils, internal steady-state Cd concentrations were reached in the viscera of the snails, the main storage organ for Cd, after 2 weeks of exposure whatever the Cd concentration in soil. The equilibrium concentrations in the viscera were 0.7 (+/-0.1), 11.3 (+/-2.4), 73.3 (+/-4.8) and 6.3 (+/-1.3) mg Cd kg(-1) dry mass for ISO 0, ISO 20, ISO 100 and ME4, respectively. During the depuration phase (3 months), from 0 to 52% of the accumulated Cd in the viscera were removed by excretion or relocation in the foot. However, the snails were not able to depurate down to initial concentrations. Data were modelled by integrating a specific growth rate constant into one-compartment toxicokinetic models. This allowed the calculation of Cd uptake rates that can be used as indicators of metal bioavailability. Since this parameter was found to be lower for snails exposed to the field soil ME4, we concluded that lower Cd bioavailability in this field soil was responsible of the lower transfer to the snails compared to the ISO 20 soil, even though they were polluted to similar extents. Internal validation showed that the toxicokinetic models could be applied for predictive purposes, promising for the development of a bioaccumulation directive for terrestrial environment.     

基于SWAT模型的细河流域蓝水绿水资源量时空分布研究

利用SWAT（Soil and Water Assessment Tool，SWAT）模型、SUFI-2算法对细河流域水文过程进行了模拟，评估了1977~2015年及典型年份流域蓝水、绿水资源量时空间分布状况。研究结果表明：（1）细河流域多年平均水资源量953.24 mm，其中蓝水资源量290.9 mm，绿水资源量662.33 mm，流域水资源构成以绿水资源为主；（2）典型年份蓝水资源变化较大，特枯水年、平水年和特丰水年分别为86、277和656 mm；绿水系数在特枯水年、平水年和特丰水年差异亦较为明显，分别为87.12%、69.78%和49.31%;（3）在空间上，细河流域蓝水呈现由东向西减少的趋势，绿水流呈现由四周向中部减少的趋势，绿水储呈现由东向西减少的趋势，在特枯水年尤为显著。     

Changes in concentrations of hydrophilic organic contaminants and of endocrine-disrupting potential downstream of small communities located adjacent to headwaters

Endocrine-disruptive potential and concentrations of polar organic contaminants were measured in seven headwaters flowing through relatively unpolluted areas of the Czech Republic. Towns with Wastewater Treatment Plant (WWTP) discharges were the first known sources of anthropogenic pollution in the areas. River water was sampled several kilometers upstream (US) and several tens of meters downstream (DS) of the WWTP discharges, by use of Pesticide and Pharmaceutical Polar Organic Integrative Samplers (POCIS-Pest, POCIS-Pharm). Extracts of passive samplers were tested by use of a battery of in vitro bioassays to determine overall non-specific cytotoxicity, endocrine-disruptive (ED) potential and dioxin-like toxicity. The extracts were also used for quantification of polar organics. There was little toxicity to cells caused by most extracts of POCIS. Estrogenicity was detected in all types of samples even though US locations are considered to be background. At US locations, concentrations of estrogen equivalents (EEq) ranged from less than the detection limits (LOD) to 0.5 ng EEq/POCIS. Downstream concentrations of EEqs ranged from less than LOD to 4.8 ng EEq/POCIS. Concentrations of EEq in POCIS extracts from all DS locations were 1 to 14 times greater than those at US locations. Concentrations of EEq measured in extracts of POCIS-Pest and POCIS-Pharm were in a good agreement. Neither antiestrogenic nor anti/androgenic activities were detected. Concentrations of 2,3,7,8-TCDD equivalents (TEq_bio) were detected in both types of POCIS at concentrations ranging from less than the LOD to 0.39 ng TEq_bio/POCIS. Nearly all extracts of POCIS-Pharm contained greater concentrations of TEq_bio activity than extracts of POCIS-Pest. Concentrations of pesticides and pharmaceuticals in extracts of POCIS were generally small at all sampling sites, but levels of some pharmaceuticals were significantly greater in both types of POCIS from DS locations. Chemical analyses along with the results of bioassays documented impacts of small towns with WWTPs on headwaters.     

Endocrine and metabolic changes in Anguilla anguilla L. following exposure to beta-naphthoflavone--a microsomal enzyme inducer

Anguilla anguilla L. were exposed during 24 and 48 h to 2.7 muM beta-naphthoflavone (BNF), a known microsomal enzyme inducer. The BNF effects on thyroid-stimulating hormone (TSH), free triiodothyronine (T3), free thyroxine (T4) and cortisol plasma levels were investigated. Alterations on plasma glucose and lactate levels were also measured as an indication of energy-mobilizing hormones alterations. BNF showed to be able to decrease significantly A. anguilla plasma T4 levels, whereas TSH, T3 and cortisol plasma remained constant. However, plasma glucose levels were significantly increased, demonstrating that intermediary metabolism has been affected. These results demonstrate that BNF a PAH-like compound alters the normal functioning of the hypothalamo-pituitary-thyroid (HPT) axis in A. anguilla.     

The purine degradation pathway: possible role in paralytic shellfish toxin metabolism in the cyanobacterium Planktothrix sp. FP1.

The paralytic shellfish toxins (PSTs) are potent neurotoxic alkaloids and their major biological effect is due to the blockage of voltage-gated sodium channels in excitable cells. They have been recognised as an important health risk for humans, animals, and ecosystems worldwide. The metabolic pathways that lead to the production and the degradation of these toxic metabolites are still unknown. In this study, we investigated the possible link between PST accumulation and the activation of the metabolism that leads to purine degradation in the filamentous freshwater cyanobacterium Planktothrix sp. FP1. The purine catabolic pathway is related to the nitrogen microcycle in water environments, in which cyanobacteria use traces of purines and ureides as a nitrogen source for growth. Thus, the activity of allantoicase, a key inducible enzyme of this metabolism, was used as tool for assaying the activation of the purine degradation pathway. The enzyme and the pathway were induced by allantoic acid, the direct substrate of allantoicase, as well as by adenine and, to a lower degree, by urea, one of the main products of purine catabolism. Crude cell extract of Escherichia coli was also employed and showed the best induction of allantoicase activity. In culture, Planktothrix sp. FP1 showed a differential accumulation of PST in consequence of the induction with different substrates. The cyanobacterial culture induced with allantoic acid accumulated 61.7% more toxins in comparison with the control. On the other hand, the cultures induced with adenine, urea, and the E. coli extract showed low PST accumulation, respectively, 1%, 38%, and 5% of the total toxins content detected in the noninduced culture. A degradation pathway for the PSTs can be hypothesised: as suggested for purine alkaloids in higher plants, saxitoxin (STX) and derivatives may also be converted into xanthine, urea, and further to CO2 and NH4+ or recycled in the primary metabolism through the purine degradation pathway.