Chromosomal Aberrations in Early Embryos of Weatherfish (Misgurnus fossilis L.) Exposed to Crude Cyanobacterial Extract and Semipurified Compound of Microcystins - a Pilot Study

The genotoxicity of semipurified compound of microcystins and crude extract of cyanobacteria was analyzed and assessed using detection of chromosomal aberrations in early life stages of weatherfish. For 96 hours, weatherfish eggs at an eye spot stage were exposed to semipurified compound of microcystins (MC-LR: ΣMC= 1: 2.6) and crude cyanobacterial extract (MC-LR: ΣMC= 1: 2.1) both at doses of 130, 50 and 13 μg l-1. Hatching time in individual groups and aberrations in the behaviour of hatched specimens were recorded. Cumulative mortality and the proportion of deformed specimens were determined; materials for histological and cytogenetic screening were simultaneously sampled. Cumulative mortality (28 and 26%, respectively) increased after the application of higher doses (130 and 50 μg l-1) of crude cyanobacterial extract (p ⪬ 0.05). In these groups, hatched embryos showed reduced agility and stayed in clusters and in the group with the highest dose of crude cyanobacterial extract white spots on yolk sacks appeared. Cytogenetic screening revealed both chromatid (gaps) and chromosomal aberrations (rings, dicentrics), percentage of which increased with the increased concentration of microcystins and the higher doses of crude cyanobacterial extract. The highest number of aberrant metaphases was recorded after the application of the highest concentrations of cyanobacterial extract and microcystin (p ⪬ 0.05). Embryo mortality was affected especially by crude cyanobacterial extract, therefore other toxic elements than microcystins present in the extract were probably involved

Karyotype and genome size of Iberochondrostoma almacai (Teleostei, Cyprinidae) and comparison with the sister-species I.lusitanicum

This study aimed to define the karyotype of the recently described Iberian endemic Iberochondrostoma almacai, to revisit the previously documented chromosome polymorphisms of its sister species I.lusitanicum using C-, Ag-/CMA3 and RE-banding, and to compare the two species genome sizes. A 2n = 50 karyotype (with the exception of a triploid I.lusitanicum specimen) and a corresponding haploid chromosome formula of 7M:15SM:3A (FN = 94) were found. Multiple NORs were observed in both species (in two submetacentric chromosome pairs, one of them clearly homologous) and a higher intra and interpopulational variability was evidenced in I.lusitanicum. Flow cytometry measurements of nuclear DNA content showed some significant differences in genome size both between and within species: the genome of I. almacai was smaller than that of I.lusitanicum (mean values 2.61 and 2.93 pg, respectively), which presented a clear interpopulational variability (mean values ranging from 2.72 to 3.00 pg). These data allowed the distinction of both taxa and confirmed the existence of two well differentiated groups within I. lusitanicum: one that includes the populations from the right bank of the Tejo and Samarra drainages, and another that reunites the southern populations. The peculiar differences between the two species, presently listed as “Critically Endangered”, reinforced the importance of this study for future conservation plans

Trust in scientists and their role in society across 67 countries

Scientific information is crucial for evidence-based decision-making. Public trust in science can help decision-makers act based on the best available evidence, especially during crises such as climate change or the COVID-19 pandemic. However, in recent years the epistemic authority of science has been challenged, causing concerns about low public trust in scientists. Here we interrogated these concerns with a pre-registered 67-country survey of 71,417 respondents on all inhabited continents and find that in most countries, a majority of the public trust scientists and think that scientists should be more engaged in policymaking. We further show that there is a discrepancy between the public’s perceived and desired priorities of scientific research. Moreover, we find variations between and within countries, which we explain with individual-and country-level variables,including political orientation. While these results do not show widespread lack of trust in scientists, we cannot discount the concern that lack of trust in scientists by even a small minority may affect considerations of scientific evidence in policymaking. These findings have implications for scientists and policymakers seeking to maintain and increase trust in scientists