New nucleic dyes for pico-and nanoplankton cytometric analysis

Flow cytometry (FCM) is a promising tool in the field of aquatic phytoplankton ecology because it allows for multi-parameter assessment of the physiological state of individual cells in an algal population. It can help to elucidate major questions such as phytoplankton taxa identification, the evaluation of cell quantity and viability, and the measuring of phytoplankton and general microbial metabolic activities. Traditionally, microalgal characterization is performed by microscopic analysis using UV-excited nuclear dyes (e.g. Hoechst and DAPI) or dyes that are excited in the blue-green part of the spectrum such as propidium iodide and eosin. The development of multi-laser cytometric systems has widened the possibilities for multi-parametric analysis and cell sorting of phytoplankton populations. Notwithstanding, significant algae autofluorescence originating from different types of chlorophyll and accessory pigments may overlap with propidium iodide and/or eosin staining and affect the resolution of algae clusters and cell sorting

New nucleic dyes for pico-and nanoplankton cytometric analysis

Flow cytometry (FCM) is a promising tool in the field of aquatic phytoplankton ecology because it allows for multi-parameter assessment of the physiological state of individual cells in an algal population. It can help to elucidate major questions such as phytoplankton taxa identification, the evaluation of cell quantity and viability, and the measuring of phytoplankton and general microbial metabolic activities. Traditionally, microalgal characterization is performed by microscopic analysis using UV-excited nuclear dyes (e.g. Hoechst and DAPI) or dyes that are excited in the blue-green part of the spectrum such as propidium iodide and eosin. The development of multi-laser cytometric systems has widened the possibilities for multi-parametric analysis and cell sorting of phytoplankton populations. Notwithstanding, significant algae autofluorescence originating from different types of chlorophyll and accessory pigments may overlap with propidium iodide and/or eosin staining and affect the resolution of algae clusters and cell sorting

Comparative DNA Cytometry of Primary and Recurrent Soft Tissue Sarcomas

The goal of comparative investigation was to reveal the distinctive features of the DNA content and cell distribution in the phases of the cell cycle of recurrent STS. DNA cytometry in the tumor tissue of 30 primary soft tissue sarcomas (t2a-2bn0M0) and 30 STS recurrences (t2-3n0M1) was carried out using the method of flow cytofluorometry. the tumor ploidy and cell distribution in the cell cycle phases were analyzed. Results. A number of differences in the DNA cytometric parameters of primary and recurrent STS have been revealed, they include: an increase in the proportion of aneuploid tumors in case of recurrence, the number of tumors with DNA index within the mitotic cycle, an increase in the proportion of cells in G2+M- phase of diploid and aneuploidy tumors and a decrease in S- phase of aneuploid ones. It has been shown that with a G2 differentiation degree, the proportion of cells in G2+M, S- and IP of recurrent STS is significantly lower than the primary parameters. An increase in the proportion of cells in G2+M- phase and a decrease in the rate of proliferation of recurrent STS, depending on the stage, are shown only in case of stage III. Conclusion. The revealed features of DNA content and cell cycle of tumor cells of soft tissue sarcomas will allow to approach to understanding of biological bases of recurrence of this malignant disease.Целью исследования было выявить в сравнительном аспекте отличительные особенности содержания ДНК и распределения клеток по фазам клеточного цикла рецидивных СМТ. Методом проточной цитофлуориметрии проводили ДНК-цитометрию в опухолевой ткани 30 первичных сарком мягких тканей (T2a-2bN0M0) и 30 – рецидивов СМТ (t2-3n0M1). анализировали плоидность опухоли и распределение клеток по фазам клеточного цикла. результаты. Выявлен ряд различий ДНК-цитометрических показателей первичных и рецидивных СМТ, которые заключаются: в увеличении доли анеуплоидных опухолей при рецидивах, числа опухолей с ИДНК в пределах митотического цикла, увеличение доли клеток в G2+M- фазе диплоидных и анеуплоидных опухолей и снижение в S-фазе анеуплоидных. Показано, что при степени дифференцировки G2 доля клеток в фазах G2+M, S- и ИП рецидивных СМТ значимо ниже параметров первичных. Увеличение доли клеток в G2+M-фазе и снижение темпов пролиферации рецидивных СМТ в зависимости от стадии показаны только при III стадии. Выводы. Выявленные особенности содержания ДНК и параметров клеточного цикла опухолевых клеток сарком мягких тканей позволят приблизиться к пониманию биологических основ рецидивирования этого злокачественного заболевания

Trait‐based analysis of subpolar North Atlantic phytoplankton and plastidic ciliate communities using automated flow cytometer

Plankton are an extremely diverse and polyphyletic group, exhibiting a large range in morphological and physiological traits. Here, we apply automated optical techniques, provided by the pulse‐shape recording automated flow cytometer—CytoSense—to investigate trait variability of phytoplankton and plastidic ciliates in Arctic and Atlantic waters of the subpolar North Atlantic. We used the bio‐optical descriptors derived from the CytoSense (light scattering [forward and sideward] and fluorescence [red, yellow/green and orange from chlorophyll a, degraded pigments, and phycobiliproteins, respectively]) and translated them into functional traits to demonstrate ecological trait variability along an environmental gradient. Cell size was the master trait varying in this study, with large photosynthetic microplankton (> 20 μm in cell diameter), including diatoms as single cells and chains, as well as plastidic ciliates found in Arctic waters, while small‐sized phytoplankton groups, such as the picoeukaryotes (< 4 μm) and the cyanobacteria Synechococcus were dominant in Atlantic waters. Morphological traits, such as chain/colony formation and structural complexity (i.e., cellular processes, setae, and internal vacuoles), appear to favor buoyancy in highly illuminated and stratified Arctic waters. In Atlantic waters, small cell size and spherical cell shape, in addition to photo‐physiological traits, such as high internal pigmentation, offer chromatic adaptation for survival in the low nutrient and dynamic mixing waters of the Atlantic Ocean. The use of automated techniques that quantify ecological traits holds exciting new opportunities to unravel linkages between the structure and function of plankton communities and marine ecosystems