Application of flow cytometry in ballast water analysis—biological aspects

Abstract

Experimental studies evaluating the effects of food availability on the movement of free-ranging animals generally involve food supplementation rather than suppression. Both approaches can yield similar insights, but we were interested in the potential for using food suppression for the management and control of invasive predators, in particular, the brown treesnake (Boiga irregularis) on Guam. However, understanding a species' response to food resources is critical before employing such a strategy. We studied the movements of 24 radio-tagged B. irregularis initially caught within four 4-ha unfenced plots in rodent-abundant (control) and rodent-suppressed (treatment) grassland habitats over a 40-day period. Because monitoring duration differed among snakes, we also analyzed short-term (16-day) activity areas. Over the 16 days, snakes associated with rodent-suppressed plots had 86% larger activity areas (ha), 94% greater dispersal distances (m), and 43% greater movement rates (m/h) than snakes associated with control plots. Boiga irregularis moved extensively, but these movements were not always reflected in the size of the snake's total activity area. Movement rates did not differ between sexes, but snakes in above-average body condition moved greater distances per hour than those in below-average condition irrespective of treatment. Our study indicates that a relatively small prey suppression effort can cause almost immediate and significant changes in B. irregularis movement. On Guam, prey suppression might enhance control efforts by either increasing trap capture success or discouraging snakes from entering areas of conservation or management concern. However, the outcome of using prey suppression as a control tool in areas threatened with the accidental introduction of the brown treesnake is more difficult to predict and might have negative consequences such as elevated dispersal rates.

Preliminary Results From Detection of Microplastics in Liquid Samples Using Flow Cytometry

“…The minimum particle size FC is able to measure is in the order of 50 nm (Steen, 2004) which imply that small microplastics (1-100 µm) can be measured. FC has been widely applied to liquid cell samples for various analyses of diseases, cell cycles, analysis of microbial community, microbial monitoring in water, in cancer research (Hoell et al, 2017) and to study cellular components like DNA, RNA, chromosomes, various hormones and proteins (Adan et al, 2016). FC coupled to viSNE has been used for detection of microplastic contamination during analysis of microbial biofilms (Sgier et al, 2016).…”

Flow Cytometric Analysis of Bacterial Protein Synthesis: Monitoring Vitality After Water Treatment

“…Common methods include culturing and selective plating of pathogens (Allen et al, 2004), microscopy analysis (Dufour et al, 2003), detection of ATP (Lee et al, 2001), and a variety of PCR-based detection of specific pathogens (Ramírez-Castillo et al, 2015). FCM has also been shown to be an efficient instrument to analyze vitality of aquatic microbes (Hammes and Egli, 2010;Hoell et al, 2017;Safford and Bischel, 2019) and has been used for example to evaluate microbial counts in recirculating aquaculture farm (Rojas Tirado et al, 2018). In spite of this, FCM is rarely used as a standard method for water analysis (Safford and Bischel, 2019), perhaps due to the lack of multicolor-based method that can explore different cell parameters at the same time (Hammes and Egli, 2010).…”

Environmental DNA Metabarcoding: A Promising Tool for Ballast Water Monitoring

“…Determining the diversity and condition of the biota discharged after BW exchange or treatment is essential to assess their potential to reduce transfer of NIS, and therefore, BW monitoring is an ongoing and active line of research. − In traditional surveys until recently BW taxa are mostly identified using morphological taxonomy ,, with some automated technologies (e.g., flow cytometry or FlowCAM) also in use. However, this technique has limitations as the organisms found in BW cover a wide range of taxa, can be damaged by sampling, and are often present at early development stages .…”