A rapid assay of phytoplankton viability

船舶吸收和释放压载水可将微生物从全球海洋的一部分输送到另一部分，对自然生态系统可能产生负面影响。为了减少外来微生物的引入带来的威胁，《控制和管理船舶压载水和沉积物国际公约》对船舶压载水的处理实施了全球法规，从2019年9月起生效。该公约对排放水中活细胞的浓度施加了限制。美国现有的法规与国际标准不同，对活细胞的排放进行了监管。根据定义，有生命的细胞能够繁殖，但没有生命的细胞不能。由于压载水处理的目的是防止微生物的繁殖，因此细胞活力为处理提供了一个合理的标准。 利用紫外线C(UVC)对压载水进行消毒，在饮用水和废水处理中得到了广泛的应用。紫外线治疗通过破坏核苷酸使细胞不能存活，但不一定直接杀死它们。因此，如果在经UVC处理的水中进行美国强制的活/死检测，非活细胞(因此是非侵入性的)细胞登记为活细胞。能否接受紫外线用于压载水处理取决于能否开发出准确的替代生存能力测试方法。 证明其可行性的最直接方法是生长试验。然而，生长分析可能需要数周时间才能完成，因此不适合进行船上测试，以确保压载水处理系统符合监管标准。在NSERC和特洛伊UV的支持下，建立了一种基于荧光的浮游植物活力(RAPV)长达数小时的快速检测方法，并在实验室进行了测试。拟议的研究伙伴关系的目标是测试RAPV的有效性；建立快速检测的理论基础；并改进确定单个细胞而不是大量组装的活性的技术。在5年内，这项研究将开发用于评估浮游植物生存能力的测试，这些测试将立即应用于压载水处理市场，但也将允许开发新的工业市场，用于评估和处理受损水域、研究自然种群以及大规模培养藻类用于食品、生物燃料和其他高价值产品。

Uptake and release of ballast water by ships can transport microorganisms from one part of the global ocean to another, with potentially negative consequences for natural ecosystems. To lessen the threat posed by the introduction of alien microorganisms, the International Convention for the Control and Management of Ships' Ballast Water and Sediments imposes global regulations for treatment of ships' ballast water, effective September 2019. The Convention imposes limits on the concentrations of viable cells in discharged waters. Existing regulations in the USA differ from the internationally standards in regulating the discharge of living cells. By definition, a viable living cell is able to reproduce, but a nonviable living cell is not. Because the goal of ballast water treatment is prevention of reproduction of microorganisms, cell viability offers a reasonable standard for treatment. Ballast water could be disinfected by application of ultraviolet C (UVC) radiation, which is widely used in treatment of drinking and waste water. UVC treatment renders cells nonviable by damaging nucleotides but does not necessarily kill them outright. Consequently, nonviable (so non-invasive) cells register as living if tested with the US-mandated live/dead assay in water treated with UVC. Acceptance of UVC for ballast water treatment depends on development of accurate alternative tests of viability. The most direct means of demonstrating viability is with a growth assay. However, growth assays can take weeks to complete, so are inappropriate for shipboard testing to ensure that a ballast water treatment system complies with regulatory standards. With the support of NSERC and Trojan UV, an hours-long fluorescence-based Rapid Assay of Phytoplankton Viability (RAPV) has been developed and tested in the laboratory. The goals of the proposed research partnership are to test the efficacy of the RAPV; to establish the theoretical foundations underlying the rapid assay; and to refine techniques for determining viability of single cells rather than bulk assemblages. Within 5 years, this research will develop tests for assessing phytoplankton viability that have immediate application to the ballast water treatment market but will also allow development of new industrial markets in assessment and treatment of impaired waters, in studies of natural populations and in mass culture of algae for food, biofuels and other high-value products.