Polymorphism & Parasites: Structure, Diversity and Selection of the MHCII Genes in a Weakly Electric Fish, Brachyhypopomus Occidentalis

The major histocompatibility complex (MHC) class II molecules play a key role in inducing an immune response, by presenting foreign peptides to T-lymphocytes. They are considered one of the most polymorphic genes in the vertebrate genome and diversity has been associated with species diversification mediated by parasite, viral and bacterial infections. While MHC genes are well documented in teleost fish, none thus far have been described in the Gymnotiform order – a highly diverse group of neotropical electric fishes. Using a combination of a recently annotated genome and whole genome resequencing data, I identified and characterized both the classical MHCII DAB, DAA and non-classical DBB genes in populations of the electric fish Brachyhypopomus occidentalis. I found highly polymorphic sites within the classical MHCII genes, and significant genetic divergence between populations widespread throughout the isthmus of Panama. To explore whether drift or selection is driving genetic diversity in MHCII genes, I compared variation between the MHCIIB and a neutral mitochondrial gene (COI). Geographic distance between sites was only correlated with variation in the COI gene, suggesting that selective pressures could be driving diversification in the MHCIIB. Further analysis showed that prevalence of parasites within drainages was associated with rate of non-synonymous mutations in the MHCIIB, which highlights the potential role parasites play in driving genetic diversity. Overall, my results highlight the highly polymorphic nature of the MHCII genes in electric fishes, and provides evidence for selection as a driver of variation at this locus. Although further analyses are needed, these findings contribute to a better understanding of what drives diversification in Neotropical electric fishes

Environmental pH modulates biofilm formation and matrix composition in Candida albicans and Candida glabrata

Candida species are fungal opportunistic pathogens capable of colonizing and infecting various human anatomical sites, where they have to adapt to distinct niche-specific pH conditions. The aim of this study was to analyse the features of Candida albicans and Candida glabrata biofilms developed under neutral and vaginal acidic (pH 4) conditions. C. albicans produced thicker and more filamentous biofilms under neutral than under acidic conditions. On the other hand, the formation of biofilms by C. glabrata was potentiated by the acidic conditions suggesting the high adaptability of this species to the vaginal environment. In general, both species developed biofilms containing higher amounts of matrix components (protein and carbohydrate) under neutral than acidic conditions, although the opposite result was found for one C. glabrata strain. Overall, this study contributes to a better understanding of the modulation of C. albicans and C. glabrata virulence by specific pH conditions.This work was supported by the Portuguese Foundation forScience and Technology (FCT)] under the scope of the stra-tegic funding of the [UID/BIO/04469/2019] unit andBioTecNorte operation [NORTE-01- 0145-FEDER-000004]funded by the European Regional Development Fund underthe scope of Norte2020–Programa Operacional Regionaldo Norte. This work was also supported by a [FCT] PhDgrant [SFRH/BD/111645/2015].info:eu-repo/semantics/publishedVersio

Biorecovery of heavy metals using vermiculite for sediment and water protection

The release of heavy metals in aquatic ecosystems is a matter of great concern due to their toxicity and accumulation in biota. Bottom sediments can act as sink of these pollutants. Several remediation technologies have been applied in order to treat wastewater and contaminated sediments. In this study, a permeable bio-barrier composed by low cost biomaterials was tested for water treatment and sediment protection against metal adsorption. The novelty of this work entails the combination of bacterial biosorption properties with the adsorption capacity of a natural clay. The results of preliminary continuous column experiments reveal the ability of vermiculite to entrap Cu ions, and highlight that metal adsorption can be enhanced by the presence of a Pseudomonas putida biofilm attached to the vermiculite surface

Catalytic reutilization of chromium-loaded NaY oxidation of ethyl acetate

EUROPACAT IX - Catalysis for a Sustainable WorldThe aim of this study is the reutilization of new materials obtained by biorecovery of chromium from water, in catalytic oxidations of volatile organic compounds. A biosorption system consisting of a microorganism supported on a NaY zeolite was used to remove hexavalent chromium from contaminated water. After the biosorption process, the chromium-loaded zeolite was used as catalyst to be applied in catalytic oxidation of ethyl acetate. The results showed that a higher content of chromium enhanced the activity and the C0 2 selectivity of the catalystinfo:eu-repo/semantics/publishedVersio

Immune response in Eimeria sp. and E. coli challenged broilers supplemented with amino acids

The aim of this study was to evaluate the immune response of broiler chickens in Eimeria sp. and E. coli challengedbroilers supplemented with glutamine, arginine and threonine. There were six hundred one-day-old male Cobb 500 broiler chickens. The design was completely randomised using a 2 x 3 factorial design (unchallenged and challenged x 3 diets). A commercial diet was used as a control and two other diets were formulated with glutamine (1.5 and 3% Aminogut®), arginine (1 and 2% L-Arginine), and threonine (1 and 2% L-threonine). At day 28, the birds fed the highest level of amino acid showed lower levels of IgA (P<0.05) compared to the control group, and resulted in an increased number of goblet cells. In the period of 1 week after the challenge, the challenged birds showed lower measures (P<0.05) of the thymus compared to the birds that had not undergone challenge. At day 28, unchallenged birds showed a reduction (P<0.05) in splenic measures in the treatment with the highest level of amino acids. The highest measures were correlated to control birds that were not challenged. At day 21, blood urea levels were increased (P<0.05) for birds fed amino acids supplementation compared to those which received no supplementation. After 28 days, uric acid levels were similar between the two supplemented diets. These results suggest that diet supplementation with amino acids above the recommended levels for growth may be necessary to improve the immune response against an Eimeria and E. coli challenge

P9 - Antimicrobial properties and bioactivity potential of smart nanoparticles for dental applications

Tooth decay is one of the greatest causes of tooth loss in the world. This not only afects the patient’s quality of life but also carries an economic burden associated with the need for multiple reinterventions. Endodontic treatment aims to preserve teeth by cleaning, disinfecting and flling/sealing the root canal. Despite the high success rate of endodontic treatment, failures do occur in a large number of cases. Several new biomaterials for dentistry have been developed, however their bioactivity is often misunderstood. Our work focuses on the biological characterization of novel bioactive glass nanoparticles, including the evaluation of their antimicrobial and biocompatibility properties. Candida albicans (ATCC 11225) and Enterococcus faecalis (ATCC 29212) were included to evaluate the antimicrobial potential by the drop plate method [1]. The cytotoxicity was tested using the MC3T3-E1 cell line, through the resazurin reduction assay. The novel bioactive glass nanoparticles demonstrated antimicrobial activity against C. albicans and E. faecalis, being able to inhibit their growth but also, in some incubation times, decreased the survival of these microorganisms. After 24 h of incubation of MC3T3-E1 osteoblast cells with bioactive glass nanoparticles conditioned medium, around 48% cell viability was achieved. These novel bioactive glass nanoparticles have shown promising properties which may fnd applications on diferent areas of clinical dentistry.info:eu-repo/semantics/publishedVersio

Intrinsically bioactive cryogels based on platelet lysate nanocomposites for hemostasis applications.

The currently used hemostatic agents are highly effective in stopping hemorrhages but have a limited role in the modulation of the wound-healing environment. Herein, we propose an intrinsically bioactive hemostatic cryogel based on platelet lysate (PL) and aldehyde-functionalized cellulose nanocrystals (a-CNCs). PL has attracted great attention as an inexpensive milieu of therapeutically relevant proteins; however, its application as a hemostatic agent exhibits serious constraints (e.g., structural integrity and short shelf-life). The incorporation of a-CNCs reinforced the low-strength PL matrix by covalent cross-linking its amine groups that exhibit an elastic interconnected porous network after full cryogelation. Upon blood immersion, the PL-CNC cryogels absorbed higher volumes of blood at a faster rate than commercial hemostatic porcine gelatin sponges. Simultaneously, the cryogels released biomolecules that increased stem cell proliferation, metabolic activity, and migration as well as downregulated the expression of markers of the fibrinolytic process. In an in vivo liver defect model, PL-CNC cryogels showed similar hemostatic performance in comparison with gelatin sponges and normal material-induced tissue response upon subcutaneous implantation. Overall, owing to their structure and bioactive composition, the proposed PL-CNC cryogels provide an alternative off-the-shelf hemostatic and antibacterial biomaterial with the potential to deliver therapeutically relevant proteins in situ.The authors thank Hospital da Prelada (Porto, Portugal) for providing adipose tissue samples and Instituto Portugues do Sangue e Transplantacio-IPST (Portugal) (Porto, Portugal) for providing platelet concentrates. The authors would like to thank Alain Morais and Isabel Pires for their support in the in vivo procedure and histological evaluation, respectively. The authors would like to thank the anonymous reviewers for all useful and helpful comments on our manuscript. This work was supported by the European Research Council grant agreement no. 772817, FCT/MCTES (Fundacio para a Ciencia e a Tecnologia/Ministerio da Ciencia, Tecnologia, e Ensino Superior) and the Fundo Social Europeu atraves do Programa Operacional do Capital Humano (FSE/POCH) in the framework of Ph.D. grant PD/59/2013-PD/BD/113807/2015 (BBM) and CEECIND/01375/2017 (MGF), Norwegian Research Council for project no. 287953

Leucine Supplementation Does Not Improve Muscle Recovery from Resistance Exercise in Young Adults: A Randomized, Double-Blinded, Crossover Study

International Journal of Exercise Science 14(2): 486-497, 2021. This study aimed to investigate the effects of free leucine supplementation on muscle recovery from resistance exercise (RE) in young adults. Fourteen untrained subjects (23.9 ± 3.6 years old) underwent RE sessions (leg press and hack squat: three sets of 8-12 reps at 70% 1RM) supplemented with leucine (LEU: two daily doses of 3g) or a placebo (PLA), separated by a seven-day washout period. Following each occasion, participants were evaluated in three subsequent days (24h, 48h, and 72h) for muscle recovery via a repetition-to-failure test. The following markers were assessed: repetition performance, perceived exertion, lactate, creatine kinase, muscle soreness (DOMS), testosterone, and cortisol. No significant difference was observed between LEU and PLA conditions (p \u3e 0.05). Number of repetitions performed in the repetition-to-failure tests, perceived exertion, cortisol, and testosterone:cortisol ratio did not change over time (p \u3e 0.05). Creatine kinase increased immediately after exercise, at 24h, and 48h, and was attenuated at 72h post-exercise, while testosterone, lactate, and DOMS increased at 24h post-exercise (p \u3c 0.05) and remained elevated up to 72h. All outcomes were similar between LEU and PLA. Results indicate that a 6g daily dose of free leucine supplementation does not improve muscle recovery following lower-limb RE in untrained young adults