“How not to judge a deer by its cover”: A personality assessment study on captive adult red deer males (Cervus elaphus)

Personality is not a uniquely human characteristic and it has been documented in a wide range of organisms, from mammals to birds, reptiles, fish, and invertebrates. However, personality is still poorly understood in Cervids. Therefore, our study aimed to fill this gap by i) investigating personality and ii) exploring its links to dominance hierarchy, assessed by behavioral observations in 11 captive and tame male red deer (Cervus elaphus). Using questionnaires to assess personality, three trained volunteers rated these animals in 15 behaviorally composed adjectives with detailed descriptions, based on their overall impression at the end of the observation period. Behavioral data from animals were collected across three different situations, namely “feeding” (i.e., high competition for a scarce resource), “normal” (i.e., no external stimuli) in a group setting, and “handling” (i.e., stressful situation due to human manipulation) in an individual setting. We estimated dominance hierarchies between the individuals based on situations of average and high competition (i.e., “normal” and “feeding”) via the Clutton-Brock Index (CBI). Using Fleiss’ Kappa for inter-rater reliability, only five of our 15 behavioral adjectives showed acceptable reliability. Using principal component analysis, four of these adjectives formed one personality component labelled “Confidence/Aggressiveness”. We found that although “Confidence/Aggressiveness” did not correlate with CBI, ratings of two adjectives loading onto this component, namely “Confident” and “Submissive”, significantly correlated with the CBI, indicating that the questionnaire ratings reflect real behavioral variation in red deer males. Our study provides the first assessment of personality in male red deer and adds to the growing literature on Cervid personality, offering the basis for future personality research in ungulates.</p

Phytoplankton blooms below the Antarctic landfast ice during the melt season between late spring and early summer

Antarctic regions are known to be mainly dominated by diatoms in the water column under sea ice. In this study, we report for the first time two distinct phytoplankton blooms dominated by nanoflagellates (< 15 µm) under the landfast ice in Terra Nova Bay during the late spring-early summer 2015-2016. The taxa included the pelagic Bolidophyceae Pentalamina corona, the Chrysophyceae Ochromonas spp. and the Chlorophyceae Chlamydomonas spp., typically found in fresh waters, and the Prymnesiophyceae Phaeocystis antarctica usually observed dominating in polynya areas. These species represented from 40% to 91% of the total phytoplankton community, a percentage contrasting with the prevalence of diatoms found previously. The dominance of nanoflagellates, rather than diatoms, during late spring and early summer may have important implications for trophic relationships in Antarctic waters and the presence of typical freshwater species could indicate a great input of continental waters related to environmental changes

A review of past and present summer primary production processes in the Ross Sea in relation to changing ecosystems

We analyse primary production processes during austral summer 1996 and 2001 in different environmental conditions such as ice-free waters and extensive ice-covered areas. Spatio-temporal distribution of phytoplankton biomass and functional groups along with photosynthetic parameters are presented. Production vs irradiance (PvsE) experiments were performed using 14C incubations at several stations and three or four different depths to define the eco-physiology of phytoplankton communities. The results of the oceanographic campaign conducted in ice-free waters of the Ross Sea (summer 1996) emphasize that these ecosystems are characterized by high nutrient low chlorophyll (HNLC) conditions due to limiting factors (eg. Fe). Conversely, the results of the oceanographic cruise in extensively packice-covered areas (summer 2001) indicate that the average phytoplankton biomass (estimated from Chla) was about three times the values recorded in ice-free conditions, but the primary production was relatively lower. In fact, in situ primary production and PvsE experiments over few days show that high primary production values occurred in most of the area, but only within the first five meters of the water column and the melting pack ice. Notwithstanding some high values of phytoplankton biomass during the 2001 campaign, water column stability, similar irradiance levels along the water column, photosynthetic capacity was suppressed in deeper layers, indicating a low carrying capacity of the pelagic ecosystem due to iron limitation, as shown by low values of the photo-chemical efficiency of photosystem II (PSII), variable fluorescence and maximal fluorescence ratio (Fv/Fm). In contrast with a very high variability in phytoplankton biomass at several temporal and spatial scales, photosynthetic parameters (PB max , α, Ek) varied within narrow ranges. Relevant changes in phytoplankton abundance and species composition are reported in this study although the environmental factors that drive these changes in primary production processes and prevalence of principal functional groups of phytoplankton communities compared to the past (1996 and 2001) are still unknown. The effect of these changes on the carrying capacity of Ross Sea ecosystems, carbon export and the potentially new asset of the food web will need to be determined

Au3+-Induced gel network formation of proteins

The formation of protein gel networks in aqueous systems is a result of protein intermolecular interactions after an energy input, like heating. In this research, we report that a redox reaction between Au3+ions and proteins can also lead to the formation of a protein gel network. Amino acids, like cysteine and tyrosine, get oxidized and form covalent bonds with neighboring protein molecules, while Au3+ions get reduced to Au+and Au0, nucleate and form gold nanoparticles. The protein gel network formation occurs within 2 h at room temperature and can be tuned by varying Au3+/protein ratio and accelerated by increasing the incubation temperature. The proposed Au3+-induced gel network formation was applied to different proteins, like egg yolk high-density lipoprotein, bovine serum albumin and whey protein. This research opens new insights for the investigation of the metal-protein interactions and may aid in the design of novel hybrid-soft nanocomposite materials

On the influence of protein aggregate sizes for the formation of solid and hollow protein microparticles

Microparticles can function as carriers of e.g. pharmaceuticals and food ingredients. Hollow microparticles can enhance the capacitance due to their large interior void. For preparing microparticles, polymers have been assembled into spherical structures through the use of porous CaCO3 templates, followed by polymer cross-linking and selective template removal. However, this often results in the formation of microparticles with a solid core. Here we use proteins with different aggregate size distributions (100 nm) to either form solid or hollow microparticles. Proteins were mixed with CaCl2 and Na2CO3 solutions, which from CaCO3 microcrystals (with 20–60 nm pores) with encapsulated proteins. Here it will be shown that small protein aggregates uniformly distributed into the CaCO3 templates. However, larger protein aggregates accumulated at the template edges. Au3+ ions were then added, which oxidize and cross-link proteins and are reduced to form gold nanoparticles (AuNPs). After removal of the templates, the small proteins formed solid microparticles and the larger protein aggregates hollow microparticles. This method of fabrication of solid and hollow protein microparticles, with embedded AuNPs, could be used for generating biomaterials with a broader range of applications, such as hosting molecules and multimodal imaging due to the presence of the AuNPs

Covalently bound monolayer patterns obtained by plasma etching on glass surfaces

Micropatterns of β-cyclodextrin (β-CD) monolayers on glass are obtained by using a plasma etching approach with polydimethylsiloxane (PDMS) stamps. This simple and versatile approach provides a promising alternative to current techniques for creating patterns of covalently bound molecules. It is also possible to fabricate sub-10 μm sized features.</p

Hollow protein microparticles formed through cross-linking by an Au3+ initiated redox reaction

Hollow microparticles (MPs) are of great relevance in the materials industry for a wide range of applications, such as catalysis, coatings, and delivery of theranostics. Here, we report the formation of hollow MPs through the assembly of lipoproteins in CaCO3 templates. Proteins interact in the pores of CaCO3 templates through attractive hydrophobic forces and form dense edges of hollow MPs. To further cross-link the proteins, Au3+ was added to initiate a redox reaction, where proteins were oxidized forming inter- and intramolecular covalent bonds, while Au3+ was reduced and gold nanoparticles (AuNPs) were formed. The obtained protein-based hollow MPs have a diameter of 6 μm and the AuNPs are embedded on their surface. Through this research, we suggest a new route to design biobased Au-protein hollow MPs in simple steps, which can allow new possibilities for carrying functional molecules and bioimaging

Covalently bound monolayer patterns obtained by plasma etching on glass surfaces

Micropatterns of β-cyclodextrin (β-CD) monolayers on glass are obtained by using a plasma etching approach with polydimethylsiloxane (PDMS) stamps. This simple and versatile approach provides a promising alternative to current techniques for creating patterns of covalently bound molecules. It is also possible to fabricate sub-10 μm sized features.</p

Microfluidic-driven short peptide hydrogels with optical waveguiding properties

Soft photonic elements with optical waveguiding ability based on biocompatible hydrogels have become increasingly important in optical techniques for medical diagnosis and phototherapy, among others. Supramolecular hydrogels based on peptides with interesting optical properties are rarely reported and explored. Although robust crystals based on short peptides have shown optical waveguiding capabilities, their rigidity is the main issue to overcome in the quest for soft biocompatible materials. Here, we report on the microfluidic-assisted formation of a heterochiral short peptide hydrogel that exhibits active optical waveguiding properties thanks to the incorporation of two different dyes, thioflavin T and rhodamine B, into the hydrogel structure. Using our microfluidic platform, different parameters such as the concentration of a peptide, type of dye and its concentration, and flow rate have been rapidly explored, with remarkable low reagent consumption. In this way, it was possible to develop peptide hydrogel waveguides with good optical loss values, modulating the emission in diverse spectral regions. The use of microfluidics to prepare these hydrogels makes possible the preparation of structures of high length-to-diameter aspect ratios, which otherwise are hard to devise from bulk conditions. Overall, this work broadens the use of supramolecular self-assembly of peptides to create functional materials with additional versatility to polymeric hydrogels, thanks to the possibility of tuning the structure by changing amino acid sequences. Additionally, the optical properties can be easily modulated by quick optimization of experimental parameters via microfluidic technology.Peer reviewe

Microfluidic-driven short peptides hydrogels with optical waveguiding property

Soft photonic elements with optical waveguiding ability based on biocompatible hydrogels have become increasingly important in optical techniques for medical diagnosis and phototherapy, among others. Supramolecular hydrogels based on peptides with interesting optical properties are rarely reported and explored. Although robust crystals based on short peptides have shown optical waveguiding capabilities, their rigidity is the main issue to overcome in the quest for soft biocompatible materials. Here, we report on a microfluidic-assisted formation of a heterochiral short peptide hydrogel that exhibit active optical waveguiding property thanks to the incorporation of two different dyes, Thioflavin T and Rhodamine B, in the hydrogel structure. Using our microfluidic platform, different parameters such as concentration of peptide, type of dye and its concentration, and flow rate have been rapidly explored, with remarkable low reagents consumption. In this way, it was possible to develop peptide hydrogel waveguides with good optical loss values, modulating the emission in diverse spectral regions. The use of microfluidics to prepare these hydrogels makes possible the preparation of structures of high length-to-diameter aspect ratio, which otherwise are hard to devise from bulk conditions. Overall, this work broadens the use of supramolecular self-assembly of peptides to create functional materials with additional versatility to polymeric hydrogels, thanks to the possibility of tuning structure by changing amino acids sequence. Additionally, the optical properties can be easily modulated by quick optimization of experimental parameters via microfluidic technology