Centre for Environmental and Marine Studies

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Organizational Unit

Publications

Temporal and geographical research trends of antimicrobial resistance in wildlife - A bibliometric analysis

Publication . Torres, Rita Tinoco; Carvalho, João; Cunha, Mónica V.; Serrano, Emmanuel; Palmeira, Josman Dantas; Fonseca, Carlos

Antimicrobial resistance (AMR) is a complex and global problem. Despite the growing literature on AMR in the medical and veterinary settings, there is still a lack of knowledge on the wildlife compartment. The main aim of this study was to report the global trends in AMR research in wildlife, through a bibliometric study of articles found in the Web of Science database. Search terms were "ANTIMICROBIAL" OR "ANTIBIOTIC" AND "RESISTANT" OR "RESISTANCE" and "WILDLIFE" "MAMMAL" "BIRD" "REPTILE" "FERAL" "FREE RANGE". A total of 219 articles were obtained, published between 1979 and 2019. A rising interest in the last decades towards this topic becomes evident. During this period, the scientific literature was distributed among several scientific areas, however it became more multidisciplinary in the last years, focusing on the "One Health" paradigm. There was a geographical bias in the research outputs: most published documents were from the United States, followed by Spain, Portugal and the United Kingdom. The most productive institutions in terms of publication number were located in Portugal and Spain. An important level of international collaboration was identified. An analysis of the main keywords showed an overall dominance of "AMR", "E. coli", "genes", "prevalence", "bacteria", "Salmonella spp." and "wild birds". This is the first study providing a global overview of the spatial and temporal trends of research related to AMR in wildlife. Given the growth tendency over the last years, it is envisaged that scientific production will expand in the future. In addition to offering a broad view of the existing research trends, this study identifies research gaps both in terms of geographical incidence and in relation to unexplored subtopics. Unearthing scientific areas that should be explored in the future is key to designing new strategic research agendas in AMR research in wildlife and to inform funding programs.

2020-12Journal article

Open access

Dynamic soaring in the winds of change: The effects of wind and oceanography on the population and spatial ecology of seabirds

Publication . Ventura, Francesco; Granadeiro, José Pedro; Catry, Paulo

Seabirds are marine top predators regarded as indicators of the environmental changes occurring in their supporting ecosystems. The analytical lens of this thesis focusses on seabird belonging to the order Procellariiformes, which have similar life-histories characterised by high life expectancy and delayed sexual maturity. Furthermore, despite acting as central place foragers during breeding, most procellariiform seabirds can perform foraging trips covering thousands of kilometres by extracting energy from the wind through a flight behaviour known as "dynamic soaring". The overarching aim of my thesis is to understand the pathways through which wind and oceanographic processes affect the demography, population dynamics, foraging ecology and spatial distribution of seabirds. Focussing on the black-browed albatross (Thalassarche melanophris) as a model organism, we developed integrated population models to investigate the effects of wind and oceanographic fluctuations on the population breeding and survival processes. By analysing a demographic database spanning nearly two decades, we found that the population breeding parameters were negatively impacted by higher sea surface temperatures and positively affected by stronger winds, presumably through bottom-up environmental processes modulating food availability and accessibility. Survival was relatively constant and was only influenced by deeper ecosystem changes acting at larger spatio-temporal scales. Furthermore, our results revealed the high sensitivity of the population to the survival rate of the poorly understood sub-adult life history stages, which comprised approximately half of the total population size. We then studied the occurrence of albatross chick mortality events not caused by predation. Our results showed that, while albatross chicks weighed less in years with warmer sea temperatures, chick malnutrition and environmentally-driven food regulation did not explain the observed patterns of mortality. Rather, nestlings mortality events unrelated to predation were clustered at small scales in time and space, suggesting that part of the pronounced inter-annual variability in albatross breeding success was modulated by the prevalence of an unidentified infectious disease. By developing state-space models, we quantified a previously hypothesised, but never empirically documented "habitat-mediated" pathway linking environmental conditions to the breeding processes of a social monogamous population. Specifically, we found a higher prevalence of divorce in challenging years characterised by warmer sea surface temperatures, documenting the direct disruptive effects of ocean warming on the social monogamous bonds of albatrosses. Our work then focussed on the hypermobile Desertas petrel (Pterodroma deserta) and Bulwer's petrel (Bulweria bulwerii) as model organisms to investigate role of winds in shaping the flight behaviour and the foraging ecology of dynamic soaring seabirds during the breeding season. Desertas petrels used favourable winds to maximise their ground speed and distance covered throughout their round-trip foraging movements, among the longest recorded in any animal. Bulwer's petrels, on the other hand, exploited the stable North Atlantic trade winds, exhibiting a striking selectivity for crosswinds and engaging in crosswind zig-zag flight throughout large sections of their tracks. Under stable winds, this strategy enabled them to maximise the distance travelled and the probability of detecting odour plumes along the round trip. Crucially, the movement patterns of these two species suggest that seabirds have a priori knowledge of the regional winds and can plan their round-trip with an expectation of predicted wind conditions and costs of flight to return back to their colony. Collectively, the findings of my thesis highlight the sensitivity of seabirds to changes in oceanographic conditions and their reliance on winds to sustain their extreme life-history. Given the accelerating pace of global change and its dramatic effects on marine ecosystems, monitoring the diagnostic responses of these "sentinels" of the global ocean and, crucially, predicting their future performance is a conservation goal of upmost importance.

2022-07Doctoral thesis

Open access

Unraveling the mysteries of chrysomya albiceps (Diptera, Calliphoridae) : Morphology, potential distribution and forensic applications

Publication . Rodrigues-Filho, Sérgio; Rebelo, Maria Teresa

Blowflies, specifically Chrysomya albiceps, hold significant importance in several fields, including forensics, sanitary, veterinary sciences, and ecology. Despite being a well-studied species, there are still knowledge gaps regarding the interplay between C. albiceps and temperature, its practical application in forensic entomology, and the analysis of anatomical ultrastructures. This thesis aims to bridge these gaps by investigating the relationship between temperature and morphology, temperature and distribution, and providing practical insights into the temperature-biology relationship and the description of two anatomical ultrastructures of C. albiceps for forensic purposes. To achieve these objectives, we employed geometric morphometry techniques, machine learning algorithms, estimatesinvolving species biology and its association with temperature (such as Accumulated Degree Days - ADD), and scanning electron microscopy (SEM). The key findings can be summarized as follows: significant differences in wing shape exist between males and females, aiding in sex identification, and wing size exhibits a negative correlation with temperature. According to the model and the variables tested in this thesis, a substantial area of Europe is climatically suitable for C. albiceps. Among the variables examined, mean annual temperature and annual temperature range were found to be the best predictors of climatic suitability. Future projections indicate an increase in climate suitability due to temperature variations. The calculations involving ADD validate the potential use of C. albiceps as a forensic indicator in criminal investigations. SEM analysis revealed previously undocumented sensillae associated with the olfactory apparatus and a possible sexual dimorphism in the locomotor apparatus of C. albiceps. These findings underscore the abundance of unexplored possibilities for the study of C. albiceps. It is anticipated that these results would provide a theoretical foundation for future research endeavors, contributing to an enhanced understanding of the species for practical applications across various scientific domains.

2024-01Doctoral thesis

Open access

How can biomolecules improve mucoadhesion of oral insulin? A comprehensive insight using ex-vivo, in silico and in vivo models

Publication . Amaral, Mariana; Martins, Ana Sofia; Catarino, José; Faísca, Pedro; Kumar, Pradeep; Pinto, João F.; Pinto, Rui; Correia, Isabel; Ascensão, Lia; Afonso, Ricardo A.; Gaspar, Catarina; Charmier, Adília J.; Figueiredo, Isabel Vitória; Reis, Catarina Pinto

Currently, insulin can only be administered through the subcutaneous route. Due to the flaws associated with this route, it is of interest to orally deliver this drug. However, insulin delivered orally has several barriers to overcome as it is degraded by the stomach’s low pH, enzymatic content, and poor absorption in the gastrointestinal tract. Polymers with marine source like chitosan are commonly used in nanotechnology and drug delivery due to their biocompatibility and special features. This work focuses on the preparation and characterization of mucoadhesive insulin-loaded polymeric nanoparticles. Results showed a suitable mean size for oral administration (<600 nm by dynamic laser scattering), spherical shape, encapsulation efficiency (59.8%), and high recovery yield (80.6%). Circular dichroism spectroscopy demonstrated that protein retained its secondary structure after encapsulation. Moreover, the mucoadhesive potential of the nanoparticles was assessed in silico and the results, corroborated with ex-vivo experiments, showed that using chitosan strongly increases mucoadhesion. Besides, in vitro and in vivo safety assessment of the final formulation were performed, showing no toxicity. Lastly, the insulin-loaded nanoparticles were effective in reducing diabetic rats’ glycemia. Overall, the coating of insulin-loaded nanoparticles with chitosan represents a potentially safe and promising approach to protect insulin and enhance peroral delivery.

2020-04-27Journal article

Open access

The Role of Rosmarinic Acid on the Bioproduction of Gold Nanoparticles as Part of a Photothermal Approach for Breast Cancer Treatment

Publication . Ferreira-Gonçalves, Tânia; Gaspar, Maria Manuela; Coelho, João M. P.; Marques, Vanda; Viana, Ana S.; Ascensão, Lia; Carvalho, Lina; Rodrigues, Cecília M. P.; Ferreira, Hugo Alexandre; Ferreira, David; Reis, Catarina Pinto

Breast cancer is a high-burden malignancy for society, whose impact boosts a continuous search for novel diagnostic and therapeutic tools. Among the recent therapeutic approaches, photothermal therapy (PTT), which causes tumor cell death by hyperthermia after being irradiated with a light source, represents a high-potential strategy. Furthermore, the effectiveness of PTT can be improved by combining near infrared (NIR) irradiation with gold nanoparticles (AuNPs) as photothermal enhancers. Herein, an alternative synthetic method using rosmarinic acid (RA) for synthesizing AuNPs is reported. The RA concentration was varied and its impact on the AuNPs physicochemical and optical features was assessed. Results showed that RA concentration plays an active role on AuNPs features, allowing the optimization of mean size and maximum absorbance peak. Moreover, the synthetic method explored here allowed us to obtain negatively charged AuNPs with sizes favoring the local particle accumulation at tumor site and maximum absorbance peaks within the NIR region. In addition, AuNPs were safe both in vitro and in vivo. In conclusion, the synthesized AuNPs present favorable properties to be applied as part of a PTT system combining AuNPs with a NIR laser for the treatment of breast cancer.

2022-01-04Journal article

Open access