Background
Flow cytometry (FCM) is one of the most commonly used technologies for analysis of numerous biological systems at the cellular level, from cancer cells to microbial communities. Its high potential and wide applicability led to the development of various analytical protocols, which are often not interchangeable between fields of expertise. Environmental science in particular faces difficulty in adapting to non-specific protocols, mainly because of the highly heterogeneous nature of environmental samples. This variety, although it is intrinsic to environmental studies, makes it difficult to adjust analytical protocols to maintain both mathematical formalism and comprehensible biological interpretations, principally for questions that rely on the evaluation of differences between cytograms, an approach also termed cytometric diversity. Despite the availability of promising bioinformatic tools conceived for or adapted to cytometric diversity, most of them still cannot deal with common technical issues such as the integration of differently acquired datasets, the optimal number of bins, and the effective correlation of bins to previously known cytometric populations.
Results
To address these and other questions, we have developed flowDiv, an R language pipeline for analysis of environmental flow cytometry data. Here, we present the rationale for flowDiv and apply the method to a real dataset from 31 freshwater lakes in Patagonia, Argentina, to reveal significant aspects of their cytometric diversities.
Conclusions
flowDiv provides a rather intuitive way of proceeding with FCM analysis, as it combines formal mathematical solutions and biological rationales in an intuitive framework specifically designed to explore cytometric diversity.
Electronic supplementary material
The online version of this article (10.1186/s12859-019-2787-4) contains supplementary material, which is available to authorized users.
This study investigated the potential effects of flunitrazepam (known as "date rape drug") on the developmental cycle of Chrysomya megacephala, an important forensic species, and their possible implications for the calculation of the PMI. A 1050 C. megacephala eggs were divided into five groups with seven replications each. The eggs were placed on artificial diet prepared with four drug concentrations of flunitrazepam (4, 8, 16, and 32 ng/g), besides the control group (prepared with water). Were evaluated the potential effects on development time, weight gain, and mortality during the cycles. The drug had no significant effect on development time or mortality although it did affect the weight of the pupae and adults (Kruskal-Wallis, p < 0.05). The result can be deduced that the determination of the postmortem interval is not affected.
1Flow cytometry (FCM) is a powerful analytical tool that is widely used worldwide, as it allows 2 the depiction of the innate complexity of a vast range of biological systems in few seconds. It 3 is a technique based on the spectroscopic properties of suspended particles that allows data to
Ocean and Coastal ResearchPicoplankton are central global carbon (C) cycling players and often dominate the ocean plankton communities, especially in low latitudes. Therefore, evaluating picoplankton temporal dynamics is critical to understanding microbial stocks and C fluxes in tropical oceans. However, the lack of studies on low-latitude picoplankton communities translates into a common conception that there is an absence of seasonality. Herein, we studied the temporal variation in abundance (measured by flow cytometry), and carbon flux (taking bacterial production and respiration as proxies) of the picoplanktonic community for the first time, as well as their environmental drivers in a low-latitude (05° 59' 20.7″S 035° 05' 14.6″W) Atlantic coastal station. We performed monthly samplings between February 2013 and August 2016 in a novel microbial observatory -hereafter called the Equatorial Atlantic Microbial Observatory -established on the northeastern Brazilian Atlantic coast. Our results revealed stability in temporal dynamics of picoplankton, despite a considerable inter-annual variation, with some related to the El Niño (ENSO) event in 2015. However, weak environmental relationships found were not enough to explain the variation in picoplankton's abundance, which suggests that other factors such as biological interactions may lead to picoplankton abundance variation over time. Heterotrophic bacteria dominated picoplankton during the entire study period and between photosynthetic counterparts, and Synechococcus showed greater relative importance than picoeukaryotes. These results bring a novel perspective that picoplankton may exhibit more pronounced fluctuations in the tropical region when considering inter-annual intervals, and is increasing prokaryotic contribution to carbon cycling towards the equator.
O presente artigo tem por objetivo analisar o conflito entre a jurisdição da Corte Interamericana de Direitos Humanos e o Supremo Tribunal Federal brasileiro acerca da Lei de Anistia, através de um breve relato da conjuntura histórica no momento de criação da Lei da Anistia; da sentença da Corte Interamericana de Direitos Humanos no caso Gomes Lund e outros; e da decisão do Supremo Tribunal Federal no sentido da constitucionalidade da lei de anistia. Analisou-se também, o controle de convencionalidade das leis, para, ao final, concluir que a ações nas esferas internacional e nacional devem ser coordenadas, para a aplicação dos direitos humanos, evitando conflitos de interpretação e proporcionando uma resposta coerente e efetiva para as pessoas vitimadas por violações desses direitos, principalmente quando esse fato foi fruto da ação direta de agentes do próprio Estado.
The nutritional and sensory qualities of tomatoes favor their acceptance worldwide. This study was carried out to evaluate the risk perception of agrochemical and sensory residue in tomato consumption. Thus, 12 kg of organic tomatoes (OT) and 12 kg of conventional tomatoes (CT) at an equal maturation stage were selected. R version 3.6.1 was applied to the analysis of physical and chemical variables. The Mann-Whitney test with a value of p<0.05 was used to verify associations between the groups. The sensory evaluation involved 37 volunteers and considered the mean answers of each question about the perception of fresh tomatoes. The OT presented about 13% more ascorbic acid in relation to CT, but there was no significant difference between them (p>0.05). OT detected higher values for pH, soluble solids (ºBrix) and titratable acidity, but there were no significant differences between them (p>0.05). Chlorfenapir residues below the Acceptable Daily Intake (IDA) value (0.03 mg/kg per capita) were detected, indicating a low risk of acute toxicity. Chlorfenapir is banned in Europe, but remains detected in Brazil. Public policies are needed to encourage sustainable food production.
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