Differing patterns of selection and geospatial genetic diversity within two leading Plasmodium vivax candidate vaccine antigens

Although Plasmodium vivax is a leading cause of malaria around the world, only a handful of vivax antigens are being studied for vaccine development. Here, we investigated genetic signatures of selection and geospatial genetic diversity of two leading vivax vaccine antigens--Plasmodium vivax merozoite surface protein 1 (pvmsp-1) and Plasmodium vivax circumsporozoite protein (pvcsp). Using scalable next-generation sequencing, we deep-sequenced amplicons of the 42 kDa region of pvmsp-1 (n = 44) and the complete gene of pvcsp (n = 47) from Cambodian isolates. These sequences were then compared with global parasite populations obtained from GenBank. Using a combination of statistical and phylogenetic methods to assess for selection and population structure, we found strong evidence of balancing selection in the 42 kDa region of pvmsp-1, which varied significantly over the length of the gene, consistent with immune-mediated selection. In pvcsp, the highly variable central repeat region also showed patterns consistent with immune selection, which were lacking outside the repeat. The patterns of selection seen in both genes differed from their P. falciparum orthologs. In addition, we found that, similar to merozoite antigens from P. falciparum malaria, genetic diversity of pvmsp-1 sequences showed no geographic clustering, while the non-merozoite antigen, pvcsp, showed strong geographic clustering. These findings suggest that while immune selection may act on both vivax vaccine candidate antigens, the geographic distribution of genetic variability differs greatly between these two genes. The selective forces driving this diversification could lead to antigen escape and vaccine failure. Better understanding the geographic distribution of genetic variability in vaccine candidate antigens will be key to designing and implementing efficacious vaccines

The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

Effects of Biosolids application on the heavy metal uptake and the interaction of cadium and lead on the growth and Cd accumulation of cabbage

受重金屬污染之土壤雖可利用翻土稀釋法或是酸洗法等技術加以整治，將土壤重金屬之濃度降低至符合法規標準，但由於此兩種技術屬於工程方法，對於土壤之基本性質及土壤品質(soil quality)具有破壞作用，整治後的農地不宜馬上投入生產的行列，需以適當之地力及肥力回復處理，使農地可以繼續耕作。污泥含有有機質、氮、磷、鉀與其他微量元素等，施用污泥可提高土壤肥力，目前國內污水廠所產生的污泥，最終處置方式以衛生掩埋為主，但台灣地區高溫多雨且地狹人稠，掩埋空間逐漸不足，且有潛在污染物滲漏至地下水的風險。歐美諸多國家在污泥的管理上，已傾向將污泥資源化處理之土地施用方式為主，台灣若能將之施用於整治後休耕農地，可達到增進土壤肥力及污泥資源化回收再利用之目的。本研究取彰化縣和美鎮受重金屬污染農田之土壤，人工配製成為不同濃度之鎘、鉛或鎘鉛污染土壤，並於土壤中添加污泥後種植小白菜，探討施用污泥及鎘鉛交互作用對小白菜生長及累積鎘濃度之影響。 研究結果發現，在Cd-Pb 為 20-0 mg/kg之土壤中，添加5%污泥可使小白菜地上部之生物量由1.60±0.27上升至2.55±0.17 g/plant (1.6倍)，但污泥亦會使地上部累積之鎘濃度、鎘總移除量及生物濃縮係數(BCF)增加，因此，如欲在農地土壤施用污泥，其土壤重金屬濃度須符合土壤污染管制標準，才不會導致食用作物小白菜累積過高之鎘。土壤添加鉛會使小白菜地上部之鎘濃度上升，與單獨只含Cd為 5 mg/kg之土壤比較，在Cd-Pb 為 5-500 mg/kg之土壤中，小白菜地上部之鎘濃度由8.8±0.92上升至11.86±2.52 mg/kg-plant (1.3倍)；在Cd-Pb 為 20-2000 mg/kg之土壤中，小白菜地上部之鎘濃度由36.4±9.83 (Cd-Pb 為 20-0 mg/kg)上升至101.91±25.13 mg/kg-plant (2.8倍)。試驗結果顯示，鉛會促進植體累積鎘，鉛對鎘之協同作用會使植物地上部之鎘濃度增加，並造成地上部生物量下降，其生物量由1.6±0.27下降至1.5±0.27 g/plant。本試驗結果亦顯示，在土壤鎘濃度大於5 mg/kg之土壤中種植小白菜，其地上部鎘濃度皆已達毒害濃度及超過每人每日攝取量，食用後會對人體造成不良影響。Soil polluted by heavy metals can be remedied through the technologies, such as soil mixing and dilution or soil acid washing. These methods could reduce the heavy metal concentrations and the uptake by plants. After the remediation, the concentrations of heavy metals could meet the soil standards. However, these two technologies are engineering methods, it may destroy the nature and the quality of soil. The remedied agricultural land is not supposed to be used for edible plant production immediately. It needs further proper restoration process to improve its fertility to make it agriculturable. Biosolids (sludge) contain abundant organic matters, nitrogen, phosphorus, potassium, and other trace elements. Applying biosolids (sludge) on soils can enhance the soil fertility. So far, in Taiwan, the most popular method to dispose the sewage sludge is sanitary landfill. However, the space for landfill is getting less and less. Especially, Taiwan is an area with high-temperature, space-limited, and dense population. Landfill is no more an acceptable method to dispose the sludge. There is also a risk for the operation of landfill. that is the potential of groundwater pollution associated with the landfill leachate. For the biosolids management on most of countries in Europe and United States, they tend to recycle biosolids (sludge) applying on farm land. We propose an alternative disposal method to reuse biosoilds. We suggested that biosolids could be applied onto the remedied and fallow farm land. These method can attain the purpose of enhancing the soil fertility and biosolids (sludge) recycling. The heavy metal contaminated soil collected from Changhua County（和美鎮） was used as the tested soil in this study. The soil was artificially added Cd, Pb, or both Cd and Pb at various concentrations. In addition to study the effect of the presence of Pb on the Cd uptake by cabbage this study also focused on the application of biosoids on the Cd uptake and its effect on the cabbage growth. The accumulation of Cd in cabbage was also studied. The results indicated that in the soil with Cd-Pb at 20-0 mg/kg, the application of 5% biosolids increased cabbage biomass from 1.60±0.27 to 2.55±0.17 g/plant (1.6 times). However, the addition of biosolids (sludge) also increased the accumulation of cadmium, total removed cadmium, and bioconcentration factor (BCF). Therefore, when biosolids were applied on farmland, the heavy meal uptake and accumulation must be monitored in order to avoid the over accumulated cadmium in edible cabbage. Addition of lead on the soil could increase the Cd uptake by cabbage. Using Cd at 5 mg/kg as a comparison, the soil with Cd-Pb at 5-500 mg/kg, Cd concentration in cabbage increased from 8.8±0.92 to 11.86±2.52 mg/kg-plant (1.3 times); in the soil with Cd-Pb at 20-2000 mg/kg, Cd concentration in cabbage increased from 36.4±9.83 (Cd-Pb at 20-0 mg/kg) to 101.91±25.13 mg/kg-plant (2.8 times). The test results showed that the presence of lead in soil would enhance the uptake and accumulation of Cd in cabbage. It would also result in reduction on the biomass production of cabbage. The cabbage biomass decreased from 1.6±0.27 to 1.5±0.27 g/plant.This test results also showed, that planting cabbage in the soil with Cd concentration over 5 mg/kg, Cd accumulation would reach the concentrations to an unacceptable level and would be over daily uptake per person. It would have adverse effect on human body after taking the cabbage harvested from the farm land with the lead concentration over 5 mg/kg in the soil.目錄 頁次 中文摘要 Ⅰ 英文摘要 Ⅱ 目錄 Ⅳ 表目錄 Ⅶ 圖目錄 Ⅷ 第一章 前言 1 1-1 研究緣起 1 1-2 研究目的 2 第二章 文獻回顧 3 2-1 農地土壤重金屬污染調查及改善工作 3 2-1-1 台灣農地調查歷程 3 2-1-2 歷年各縣市農地土壤污染調查結果 5 2-1-3 農地土壤污染改善情形 5 2-2 重金屬概述 11 2-2-1 重金屬之物化特性與毒理資料 11 2-2-2 重金屬於環境中之傳輸途徑 14 2-2-3 重金屬污染對植物及人體之影響 16 2-2-4 植物體對重金屬之吸收與忍受程度 21 2-2-5 重金屬間的交互作用對植物累積重金屬的影響 24 2-3 彰化縣農地重金屬污染問題探討 24 2-3-1 東西二圳灌溉系統 24 2-3-2 農地與渠道污染的相關性 28 2-3-3 彰化縣農地重金屬污染改善 31 2-4 鎘米 40 2-5 鎘、鉛之特性及其對植物之危害 42 2-5-1 鎘、鉛在土壤中之含量 42 2-5-2 鎘與鉛之特性 43 2-6 污泥 51 2-6-1 我國下水污泥處置現況與趨勢 51 2-6-2 下水污泥資源化技術與管理制度 51 2-6-3 施用下水污泥對作物品質與產量的影響 57 2-6-4 下水污泥施用後植體中重金屬含量之變化 57 2-6-5 下水污泥施用後植體中重金屬含量之變化 58 2-6-6 台灣地區有關污泥土地施用之研究 60 第三章 材料與方法 62 3-1 供試土壤基本性質分析 62 3-2 鎘、鉛污染土壤添加污泥試驗 64 3-2-1 人工配製鎘、鉛及污泥污染土壤 64 3-2-2 盆栽試驗 64 第四章 結果與討論 66 4-1 供試土壤的基本理化性質 66 4-2 土壤鎘濃度對小白菜之影響 68 4-2-1 對生物量之影響 68 4-2-2 對地上部植體鎘吸收之影響 68 4-2-3 對地上部鎘總移除量之影響 70 4-2-4 對BCF值之影響 70 4-3於鎘污染土壤中添加污泥對小白菜之影響 72 4-3-1 對生物量之影響 72 4-3-2 對地上部鎘吸收之影響 72 4-3-3 對地上部鎘總移除量之影響 74 4-3-4 對BCF值之影響 74 4-3-5污泥添加之效應 74 4-4 鎘鉛交互作用對小白菜之影響 76 4-4-1 對小白菜生物量之影響 76 4-4-2 對地上部鎘累積濃度之影響 78 4-4-3 對地上部鎘總移除量之影響 80 4-4-4 對BCF值之影響 80 4-5小白菜移除土壤鎘濃度之成效 82 4-5-1不同土壤鎘濃度之成效 82 4-4-2添加污泥之效應 82 4-6小白菜可食用部份鎘累積濃度之分析結果與危害性評估 83 第五章 結論與建議 84 5-1 結論 84 5-2 建議 86 第六章 參考文獻 87 表目錄 表2-1各縣市累計公告列管農地土壤控制場址統計 7 表2-2各縣市農地污染改善方式及整治經費表 8 表2-3各縣市累計解除農地土壤控制場址列管統計 10 表2-4重金屬物化特性與毒理資料 12 表2-5重金屬對作物及人體的影響 18 表2-6每人每日重金屬攝取量及人體可攝取之限值 18 表2-7重金屬對作物毒害濃度與食物中之容許含量 19 表2-8聯合國農糧組織/世界衛生食品安全標準委員會提出不同食品中鎘之最大容許量 20 表2-9作物中重金屬含量與土壤中重金屬含量之比值 22 表2-10植物體對重金屬之忍受程度 23 表2-11東西二圳抽水設施與灌溉系統面積 25 表2-12彰化工作站東西二圳工作小組分類 25 表2-13美國EPA土壤重金屬污染整治技術及影響因子之評估 32 表2-14國內農地整治案例 33 表2-15彰化縣92-94年執行農地污染改善各項污染改善工法之適用性 比較 39 表2-16為土壤及作物影響因子對作物吸收鎘之影響效果 41 表2-17鎘在水稻各部位的含量分布 46 表2-18鉛對白菜生長及產量的影響 50 表2-19各種下水污泥資源化技術比較 53 表2-20消化氣體與其他各種燃料發熱量的比較 54 表2-21污泥熔渣之用途 54 表2-22典型生物污泥之化學特性 55 表2-23生物污泥與商業肥料肥份之比較 56 表2-24堆肥與土壤改良之比較 56 表4-1盆栽試驗後土壤中之鎘全量濃度 67 圖目錄 圖2-1重金屬污染途徑 15 圖2-2東西二圳主支圖流灌溉系統分支圖 26 圖2-3東西二圳主支流灌溉系統分佈圖 27 圖2-4農田土壤污染經由含污染物灌溉用水傳播之途徑 30 圖2-5當污泥土地施用停止或繼續施用時植體重金屬高原理論示意圖 60 圖4-1於不同鎘濃度土壤中生長35天後，小白菜地上部之乾重 69 圖4-2於不同鎘濃度土壤中生長35天後，小白菜地上部鎘累積濃度69 圖4-3於不同鎘濃度土壤中生長35天後，小白菜地上部鎘總移除量71 圖4-4於不同鎘濃度土壤中生長35天後BCF值之變化 71 圖4-5添加污泥對生長於不同鎘濃度土壤中小白菜地上部乾重之影響 73 圖4-6添加污泥對生長於不同鎘濃度土壤中小白菜地上部鎘累積濃度 之影響 73 圖4-7添加污泥對生長於不同鎘濃度土壤中小白菜地上部鎘總移除量 之影響 75 圖4-8添加污泥對生長於不同鎘濃度土壤中小白菜地上部BCF值之 影響 75 圖4-9鎘鉛交互作用對小白菜地上部生物量之影響 77 圖4-10鎘鉛交互作用對小白菜地上部鎘累積濃度之影響 79 圖4-11鎘鉛交互作用對小白菜地上部鎘總移除量之影響 81 圖4-12鎘鉛交互作用對小白菜BCF值之影響 8

Innovation and ownership variety

The role of ownership heterogeneity in influencing the extent and nature of innovation has been neglected but is an important omission as ownership differences can influence the goals, time horizons, and governance mechanisms relating to innovation. In this article I develop a novel framework that explores the potential impact and future research avenues in firms with a variety of ownership forms based on whether the organizational form in which innovation takes place is either a new venture or an existing business, and whether ownership involves new independent owners or existing independent owners of the organization. With respect to organizational form, new ventures are effectively locked into innovation by definition, while existing businesses may find a balance between investing in innovation and exploiting previous innovations, and engaging in more incremental innovation. Existing independent owners may be expected to take a more sustained view of innovation over time while new owners may be time delimited in their innovation. On the basis of this framework I analyze the following ownership types: academic spin-offs, private equity backed management buyouts, family firms and firms owned by habitual entrepreneurs. I identify the need for research to explore other ownership forms and the interaction between ownership types and different contexts