Genetic and morphometric variation in Schwarziana quadripunctata and Schwarziana mourei (Hymenoptera: Apidae: Meliponini)

Schwarziana bees are a ground-nesting stingless bee distributed in the Neotropical region. Schwarziana quadripunctata was the first described and the most studied species of this genus. Now, there are four valid species of Schwarziana bees, but it has been suggested that the diversity of this taxon may be higher, due to undescribed cryptic species. In this study, we investigated the populational diversity of S. quadripunctata using workers collected at 11 localities in Brazil (from the Northeast to South region). We also included one population of S. mourei (collected in São Paulo state, 2 nests). We analysed the bees using geometric morphometrics and molecular analyses amplifying mtDNA cytochrome oxidase I (COI) and 16S to access the diversity among the populations. From the results of geometric morphometrics, the Mahalanobis distances between S. mourei and S. quadripunctata are greater than those distances among S. quadripunctata populations. A similar scenario can also be observed looking to the phylogenetic tree generated by the molecular markers. Morphometry and molecular markers data showed significant association with geographic distance, indicating the existence of intrapopulation variation in S. quadripunctata. Our hypothesis was supported, that the populations of S. quadripunctata showed differences in haplotypic diversity. Overall, these analyses revealed a moderate level of intraspecific variation among S. quadripunctata populations and discriminated well the species S. quadripunctata from S. mourei

Single-molecule measurements reveal that PARP1 condenses DNA by loop stabilization

Poly(ADP-ribose) polymerase 1 (PARP1) is an abundant nuclear enzyme that plays important roles in DNA repair, chromatin organization and transcription regulation. Although binding and activation of PARP1 by DNA damage sites has been extensively studied, little is known about how PARP1 binds to long stretches of undamaged DNA and how it could shape chromatin architecture. Here, using single-molecule techniques, we show that PARP1 binds and condenses undamaged, kilobase-length DNA subject to sub-piconewton mechanical forces. Stepwise decondensation at high force and DNA braiding experiments show that the condensation activity is due to the stabilization of DNA loops by PARP1. PARP inhibitors do not affect the level of condensation of undamaged DNA but act to block condensation reversal for damaged DNA in the presence of NAD+. Our findings suggest a mechanism for PARP1 in the organization of chromatin structure

Indoor Air Quality in Elderly Centers: Pollutants Emission and Health Effects

The world population is ageing, in particular in the developed world, with a significant increase in the percentage of people above 60 years old. They represent a segment of the population that is more vulnerable to adverse environmental conditions. Among them, indoor air quality is one of the most relevant, as elders spend comparatively more time indoors than younger generations. Furthermore, the recent COVID-19 pandemic contributed immensely to raising awareness of the importance of breathing air quality for human health and of the fact that indoor air is a vector for airborne infections and poisoning. Hence, this work reviews the state of the art regarding indoor air quality in elderly centers, considering the type of pollutants involved, their emission sources, and their health effects. Moreover, the influence of ventilation on air quality is also addressed. Notwithstanding the potential health problems with the corresponding costs and morbidity effects, only a few studies have considered explicitly indoor air quality and its impacts on elderly health. More studies are, therefore, necessary to objectively identify what are the impacts on the health of elderly people due to the quality of indoor air and how it can be improved, either by reducing the pollutants emission sources or by more adequate ventilation and thermal comfort strategies. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was financially supported by base funding of the following projects: LA/P/0045/2020 (ALiCE), UIDB/00511/2020 (LEPABE), and UIDB/50022/2020 (LAETA), funded by national funds through FCT/MCTES (PIDDAC). Fátima Felgueiras gratefully acknowledges the Portuguese National Funding Agency for Science, Research, and Technology (FCT) for the financial support through the Grant BD/6521/2020. António Martins thanks FCT for funding through program DL 57/2016—Norma transitória. Teresa Mata gratefully acknowledge the funding of Project NORTE-06-3559-FSE-000107, cofinanced by Programa Operacional Regional do Norte (NORTE2020), through Fundo Social Europeu (FSE)

Microdevices for extensional rheometry of low viscosity elastic liquids : a review

Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations

Behavioural stress responses predict environmental perception in European sea bass (Dicentrarchus labrax)

Individual variation in the response to environmental challenges depends partly on innate reaction norms, partly on experience-based cognitive/emotional evaluations that individuals make of the situation. The goal of this study was to investigate whether pre-existing differences in behaviour predict the outcome of such assessment of environmental cues, using a conditioned place preference/avoidance (CPP/CPA) paradigm. A comparative vertebrate model (European sea bass, Dicentrarchus labrax) was used, and ninety juvenile individuals were initially screened for behavioural reactivity using a net restraining test. Thereafter each individual was tested in a choice tank using net chasing as aversive stimulus or exposure to familiar conspecifics as appetitive stimulus in the preferred or non preferred side respectively (called hereafter stimulation side). Locomotor behaviour (i.e. time spent, distance travelled and swimming speed in each tank side) of each individual was recorded and analysed with video software. The results showed that fish which were previously exposed to appetitive stimulus increased significantly the time spent on the stimulation side, while aversive stimulus led to a strong decrease in time spent on the stimulation side. Moreover, this study showed clearly that proactive fish were characterised by a stronger preference for the social stimulus and when placed in a putative aversive environment showed a lower physiological stress responses than reactive fish. In conclusion, this study showed for the first time in sea bass, that the CPP/CPA paradigm can be used to assess the valence (positive vs. negative) that fish attribute to different stimuli and that individual behavioural traits is predictive of how stimuli are perceived and thus of the magnitude of preference or avoidance behaviour.European Commission [265957]; Portuguese Fundacao para a Ciencia e Tecnologia (FCT) [FRH/BPD/72952/2010]; FCT [SFRH/BD/80029/2011