Individual recognition is associated with holistic face processing in Polistes paper wasps in a species-specific way

Most recognition is based on identifying features, but specialization for face recognition in primates relies on a different mechanism, termed ‘holistic processing’ where facial features are bound together into a gestalt which is more than the sum of its parts. Here, we test whether individual face recognition in paper wasps also involved holistic processing using a modification of the classic part-whole test in two related paper wasp species: Polistes fuscatus, which use facial patterns to individually identify conspecifics, and Polistes dominula, which lacks individual recognition. We show that P. fuscatus use holistic processing to discriminate between P. fuscatus face images but not P. dominula face images. By contrast, P. dominula do not rely on holistic processing to discriminate between conspecific or heterospecific face images. Therefore, P. fuscatus wasps have evolved holistic face processing, but this ability is highly specific and shaped by species-specific and stimulus-specific selective pressures. Convergence towards holistic face processing in distant taxa (primates, wasps) as well as divergence among closely related taxa with different recognition behaviour (P. dominula, P. fuscatus) suggests that holistic processing may be a universal adaptive strategy to facilitate expertise in face recognition.     

Threatened fish species in the Northeast Atlantic are functionally rare

Aim

The criteria used to define the International Union for Conservation of Nature (IUCN) Red List categories are essentially based on demographic parameters at the species level, but they do not integrate species' traits or their roles in ecosystems. Consequently, current IUCN-based protection measures may not be sufficient to conserve ecosystem functioning and services. Some species may have a singular combination of traits associated with unique functions. Such functionally distinct species are increasingly recognized as a key facet of biodiversity since they are, by definition, functionally irreplaceable. The aim of this study is to investigate whether threatened species are also functionally rare and to identify which traits determine extinction risk.

Location

European continental shelf seas.

Time period

1984–2020.

Major taxa studied

Marine fish.

Methods

Using newly compiled trait information of 425 marine fish species in European waters, and more than 30 years of scientific bottom trawl surveys, we estimated the functional distinctiveness, restrictedness and scarcity of each species and cross-referenced it with their IUCN conservation status.

Results

In European continental shelf seas, 38% of the species threatened with extinction (9 out of 24 species) were identified as the most functionally distinct. By mapping extinction risk in the multidimensional species trait space, we showed that species with the greatest risk of extinction are long-lived and of high trophic level. We also identified that the most functionally distinct species are sparsely distributed (4% of the total area on average) and have scarce abundances (<1% of the relative mean abundance of common species).

Main Conclusions

Because a substantial proportion of threatened species are functionally distinct and thus may play unique roles in ecosystem functioning, we stress that species traits—especially functional rarity—should become an indispensable step in the development of conservation management plans.     

Differential Influence of Life Cycle on Growth and Toxin Production of three Pseudo‐nitzschia Species (Bacillariophyceae)

We used a multistrain approach to study the intra‐ and interspecific variability of the growth rates of three Pseudo‐nitzschia species – P. australis, P. fraudulenta, and P. pungens – and of their domoic acid (DA) production. We carried out mating and batch experiments to investigate the respective effects of strain age and cell size, and thus the influence of their life cycle on the physiology of these species. The cell size – life cycle relationship was characteristic of each species. The influence of age and cell size on the intraspecific variability of growth rates suggests that these characteristics should be considered cautiously for the strains used in physiological studies on Pseudo‐nitzschia species. The results from all three species do not support the hypothesis of a decrease in DA production with time since isolation from natural populations. In P. australis, the cellular DA content was rather a function of cell size. More particularly, cells at the gametangia stage of their life cycle contained up to six times more DA than smaller or larger cells incapable of sexual reproduction. These findings reveal a link between P. australis life cycle and cell toxicity. This suggest that life cycle dynamics in Pseudo‐nitzschia natural populations may influence bloom toxicity.     

Fluorescence-based real time monitoring and diagnostics of recombinant Pichia pastoris cultivations in a bioreactor

This study describes the application of the multivariate curve resolution (MCR) analysis technique for real-time analysis of culture fluorescence during recombinant Pichia pastoris cultivation in a bioreactor. Fluorescence spectra were acquired with an on-line dual excitation wavelength fluorometer and then used to develop a real time MCR-based bioprocess monitoring and diagnostics tool. Initial bioreactor experiments using two similar recombinant antibody secreting P. pastoris cell lines showed significant differences in protein production. To distinguish between the contributions of operating conditions and the specific cell line's genetic composition to the observed differences in protein production, the bioreactor experiments were repeated and accompanied by real time MCR analysis. The tests demonstrated high sensitivity of MCR-derived “pure concentration” profiles to growth as well as to initial conditions, thus enabling real-time cultivation process trend diagnostics and fault detection. © 2018 Her Majesty the Queen in Right of Canada © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2761, 2019.     

How long is too long? Effects of loop size on G-quadruplex stability

We compared here 80 different sequences containing four tracts of three guanines with loops of variable length (between 1 and 15 bases for unmodified sequences, up to 30 for fluorescently labeled oligonucleotides). All sequences were capable of forming stable quadruplexes, with T_m above physiological temperature in most cases. Unsurprisingly, the melting temperature was systematically lower in sodium than in potassium but the difference between both ionic conditions varied between 1 and >39°C (average difference: 18.3°C). Depending on the sequence context, and especially for G4 sequences involving two very short loops, the third one may be very long without compromising the stability of the quadruplex. A strong inverse correlation between total loop length and T_m was found in K⁺: each added base leads to a 2°C drop in T_m or ∼0.3 kcal/mol loss in ΔG°. The trend was less clear in Na⁺, with a longer than expected optimal loop length (up to 5 nt). This study will therefore extend the sequence repertoire of quadruplex-prone sequences, arguing for a modification of the widely used consensus (maximal loop size of 7 bases).     

Ageing and endurance training effects on quantity and quality of pulmonary vascular bed in healthy men

It has recently been demonstrated that in healthy individuals, peak oxygen consumption is associated with a greater pulmonary capillary blood volume and a more distensible pulmonary circulation. Our cross-sectional study suggests that, in healthy men aged 20 to 60 years (n = 63), endurance sport practice (vigorous-intensity domain of the International Physical Activity Questionnaire) is associated with better quantity (pulmonary capillary blood volume) and quality (slope of increase in lung diffusion for carbon monoxide on exercise) of the pulmonary vascular bed, partly counterbalancing the deleterious effects of ageing, which remains to be demonstrated in a prospective longitudinal design.