Addressing multiple facets of bias and uncertainty in continental scale biodiversity databases

The availability of biodiversity databases is expanding at unprecedented rates. Nevertheless, species occurrence data can be intrinsically biased and contain uncertainties that impact the accuracy and reliability of biodiversity estimates. In this study, we developed a reproducible framework to assess three dimensions of bias—taxonomic, spatial, and temporal—as well as temporal uncertainty associated with data collections. We utilized the vegetation plot data located in Europe, from sPlotOpen, an open-access database, as a case study. The metrics proposed for estimating bias include completeness of the species richness for taxonomic bias, Nearest Neighbor Index for spatial bias, and Pielou’s index for temporal bias. Additionally, we introduced a new method based on a negative exponential curve to model the temporal decay in biodiversity data, aiming to quantify temporal uncertainty. Finally, we assessed the sampling bias considering the influence of various spatial variables (i.e, road density, human population count, Natura 2000 network and topographic roughness). We discovered that the facets of bias and the temporal uncertainty varied throughout Europe, as did the different roles played by spatial variables in determining biases. sPlotOpen showed a clustered distribution of the vegetation plots, and an uneven distribution in sampling completeness, year of sampling and temporal uncertainty. The facets of bias were significantly explained mainly by the presence of Natura 2000 network and marginally by the human population count. These results suggest that employing an efficient procedure to examine biases and uncertainties in data collections can enhance data quality and provide more reliable biodiversity estimates

Negative Evidence for Sex-Linked Heteroplasmy in the Nemertean Worm Notospermus geniculatus (Delle Chiaje, 1822)

Doubly Uniparental Inheritance (DUI) is considered one of the major exceptions to the common rules of eukaryotic cell biology and germline formation. DUI is known in bivalves, which belong to the phylum Mollusca; conversely, no DUI evidence was found in some gastropod species. Investigating the presence of DUI in Nemertea is of particular interest given the fact that these spiralian animals are suggested to be a sister group of Neotrochozoa (i.e., Mollusca and Annelida). DUI species are normally detected as having two sex-associated mtDNAs, which can be highly divergent. In this work, the presence of sex-associated mitochondrial genomes was investigated in the nemertean species Notospermus geniculatus and no evidence was found for DUI. Even if these are preliminary results, negative evidence is still interesting because of the high importance of the DUI phenomenon in many research fields, where it plays a pivotal role in understanding eukaryotic evolution. For this reason, further research on DUI species detection should be highly encouraged, as well as the publication of negative results beside positive ones, as is the case for the present study, improving the knowledge on the biology and ecology of a broad spectrum of marine species

Temperature-Related Effects of Myocardial Protection Strategies in Swine Hearts after Prolonged Warm Ischemia

Insufficient supply of cardiac grafts represents a severe obstacle in heart transplantation. Donation after circulatory death (DCD), in addition to conventional donation after brain death, is one promising option to overcome the organ shortage. However, DCD organs undergo an inevitably longer period of unprotected warm ischemia between circulatory arrest and graft procurement. In this scenario, we aim to improve heart preservation after a warm ischemic period of 20 min by testing different settings of myocardial protective strategies. Pig hearts were collected from a slaughterhouse and assigned to one of the five experimental groups: baseline (BL), cold cardioplegia (CC), cold cardioplegia + adenosine (CC-ADN), normothermic cardioplegia (NtC + CC) or normothermic cardioplegia + cold cardioplegia + adenosine (NtC-ADN + CC). After treatment, tissue biopsies were taken to assess mitochondrial morphology, antioxidant enzyme activity, lipid peroxidation and cytokine and chemokine expressions. NtC + CC treatment significantly prevented mitochondria swelling and mitochondrial cristae loss. Moreover, the antioxidant enzyme activity was lower in this group, as was lipid peroxidation, and the pro-inflammatory chemokine GM-CSF was diminished. Finally, we demonstrated that normothermic cardioplegia preserved mitochondria morphology, thus preventing oxidative stress and the subsequent inflammatory response. Therefore, normothermic cardioplegia is a better approach to preserve the heart after a warm ischemia period, with respect to cold cardioplegia, before transplantation