Finding a needle in a haystack: DNA Haemoproteus columbae enrichment using percoll density gradient and flow cytometry.

Isolation of genomic DNA of blood parasites in birds, reptiles, amphibians, and fishes is a challenging task, given that their red blood cells are nucleated; for that reason, parasite genomic DNA is only a fraction of the total extracted DNA, and it is challenging to obtain concentrated high-quality genetic material. Percoll Density Gradient (PDG) and flow cytometry are tools for separating and analyzing cell populations or even a single cell, and both represent potent approaches for isolating avian haemosporidians parasites. Our experimental design included several steps seeking to concentrate the parasite´s DNA. We used blood samples from a Rock pigeon infected with Haemoproteus columbae. After inducing parasite exflagellation and gametogenesis in vitro, we subjected the samples to a Percoll Density Gradient to separate the parasites from the rest of the blood cells. Following centrifugation, the layer containing extracellular parasites underwent a flow cytometry and cell sorting process, during which we selected two different subpopulations of cells for analysis. Based on qPCR analyses, we demonstrate parasite DNA enrichment in Percoll Density Gradient and flow cytometry samples; simultaneously, these samples showed the lowest concentration of Columba livia DNA. However, the concentration of parasite DNA was higher in the PDG than in the cell sorting sample. This study reports the concentration of the Haemoproteus parasite by flow cytometry without DNA-intercalating dyes, and this methodology can serve as a technique for DNA enrichment of blood parasites infecting nucleated red blood cells to improve techniques that allow obtaining complete genomes.

Publicación y retractación en la era del SARS-CoV-2 y la COVID-19 / Publication and retraction in the era of SARS-Cov-2 and COVID-19

La pandemia ocasionada por el SARS-CoV-2 aceleró el tiempo de revisión y aceptación de manuscritos, aumentó el libre acceso a la información publicada sobre el tema y popularizó los servidores de manuscritos, versiones preliminares o preprints. Es por ello que el objetivo del estudio se centró en evaluar las tendencias en la dinámica de las retractaciones y determinar patrones existentes entre las variables analizadas. Se realizó un análisis bibliométrico de artículos asociados con la pandemia, en el que se evaluaron las tendencias y dinámicas de 103 manuscritos retractados entre diciembre de 2019 y junio 2021. Con ello se evidenció una asociación positiva con un menor tiempo de revisión, como también con manuscritos publicados en revistas Q1 y Q2 de Scimago Journal Rank. Asimismo, el número de artículos retractados disminuyó nueve meses después de la declaratoria de pandemia. Si bien la pandemia impactó positivamente en el proceso de difusión de la información científica, las políticas editoriales deberían incluir mecanismos de control que persuadan a los autores acerca de comportamientos antiéticos(AU)

The pandemic caused by SARS-CoV-2 accelerated the review and acceptance time of manuscripts, increased free access to published information on the subject, and popularized manuscript servers, preliminary versions, or preprints. That is why the objective of the study focused on evaluating the trends in the dynamics of retractions and determining existing patterns among the variables analyzed. A bibliometric analysis of articles associated with the pandemic was carried out. The trends and dynamics of 103 retracted manuscripts from December 2019 to June 2021 were evaluated. This evidenced an inspiring association with shorter review time, as well as with manuscripts published in Q1 and Q2 journals of Scimago Journal Rank. Likewise, the number of retracted articles decreased nine months after the declaration of a pandemic. Although the pandemic positively impacted on the process of disseminating scientific information, editorial policies should include control mechanisms that persuade authors about unethical behavior(AU)