Neuropeptides display antimicrobial activity against cariogenic and endodontic bacteria

Introduction: Many neuropeptides are similar in size, amino acid composition and charge to antimicrobial peptides. It is therefore possible that the nervous system employs neuropeptides as antimicrobial agents by delivering them rapidly and precisely to innervated sites such as the dental pulp. Objectives: The aim of this study was to determine whether the neuropeptides substance P (SP), neurokinin A (NKA), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), which we have previously shown to be present in dental pulp, displayed antimicrobial activity against the cariogenic bacterium Streptococcus mutans and the endodontic bacterium Enterococcus faecalis. Methods: Neuropeptides were purchased from Bachem and utilised in antibacterial assays using a previously described ultra sensitive radial diffusion method. Results: Antimicrobial activity was identified as clear zones around neuropeptide-containing wells. NPY was found to exhibit antimicrobial against both Streptococcus mutans and Enterococcus faecalis. SP and VIP were shown to exhibit antimicrobial activity against Streptococcus mutans only. The neuropeptides NKA and CGRP did not show antimicrobial activity against either micro-organism. Conclusion: This study is the first to describe an antimicrobial role for neuropeptides in pulp biology. The antimicrobial actions of neuropeptides contribute a novel aspect to pulpal defence against cariogenic and endodontic bacteria worthy of further investigation.

Diabetes Distress: Understanding the Hidden Struggles of Living with Diabetes and Exploring Intervention Strategies

Diabetes Distress is a rational emotional response to the threat of a life-changing illness. Distinct from depression, it is rooted in the demands of diabetes management and is a product of psychological adjustment. Diabetes distress has been found to be significantly associated with HbA1c and self-care, which demonstrates its clinical use in treatment outcomes. Interpersonal factors such as perceived support and protectiveness of partners significantly contribute to elevated distress, suggesting that these are valued areas of focus for interventions. Pioneering large-scale research, DAWN2, gives voices to the families of those with diabetes and reaffirms the need to consider psychosocial factors in routine diabetes care. Structured diabetes education programmes are the most widely used in helping individuals cope with diabetes, but they fail to consider the psychological or interpersonal aspects of diabetes management. Psycho-educational approaches are found to be effective in reducing diabetes distress while also improving HbA1c. Certain limitations in the current literature are discussed, along with future directions. Of utmost importance is the need for health practitioners, irrespective of background, to demonstrate an understanding of diabetes distress and actively engage in discussion with individuals struggling to cope with diabetes; to normalize this and integrate it into routine diabetes practice.

Lipopolysaccharide modification in Gram-negative bacteria during chronic infection

The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation, and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host-pathogen interaction.

Living to the range limit: consumer isotopic variation increases with environmental stress

Background: Theoretically, each species’ ecological niche is phylogenetically-determined and expressed spatially as the species’ range. However, environmental stress gradients may directly or indirectly decrease individual performance, such that the precise process delimiting a species range may not be revealed simply by studying abundance patterns. In the intertidal habitat the vertical ranges of marine species may be constrained by their abilities to tolerate thermal and desiccation stress, which may act directly or indirectly, the latter by limiting the availability of preferred trophic resources. Therefore, we expected individuals at greater shore heights to show greater variation in diet alongside lower indices of physiological condition.

Methods: We sampled the grazing gastropod Echinolittorina peruviana from the desert coastline of northern Chile at three shore heights, across eighteen regionally-representative shores. Stable isotope values (δ13C and δ15N) were extracted from E. peruviana and its putative food resources to estimate Bayesian ellipse area, carbon and nitrogen ranges and diet. Individual physiological condition was tracked by muscle % C and % N.

Results: There was an increase in isotopic variation at high shore levels, where E. peruviana’s preferred resource, tide-deposited particulate organic matter (POM), appeared to decrease in dietary contribution, and was expected to be less abundant. Both muscle % C and % N of individuals decreased with height on the shore.

Discussion: Individuals at higher stress levels appear to be less discriminating in diet, likely because of abiotic forcing, which decreases both consumer mobility and the availability of a preferred resource. Abiotic stress might be expected to increase trophic variation in other selective dietary generalist species. Where this coincides with a lower physiological condition, this may be a direct factor in setting their range limit.

Waiting for International Political Sociology: A Field Guide to Living In-Between

This paper explores the in-between positionality of International Political Sociology (IPS) and offers a field guide to help scholars, students and thinkers embrace this disposition more energetically. It makes the case for a more balanced transdisciplinarity that attends to the international, the political and the social at the same time and in equal measure. The power of this in-between approach is that it forces thinkers in IPS to constantly look at the horrors of our contemporary world without turning away. Through the ambivalent position of the ‘happy wreck’, the paper explores the need to do something about these horrors (e.g. diagnose, act, intervene) while fully acknowledging that such actions always produce new forms of violence and exclusion. To help thinkers in IPS inhabit this challenging space of inquiry more confidently, the paper makes four suggestions: (i) broadening our emotional responses to the horrors of the world; (ii) resisting resolution through non-cathartic dispositions; (iii) pursuing slow research to contest dominant rhetorics of crisis and emergency; and (iv) re-imagining shared conditions of vulnerability.

Risk indicators associated with root decay in independently living older adults

Objective: To determine the risk indicators associated with root caries experience in a cohort of independently living older adults in Ireland.
Methods: The data reported in the present study were obtained from a prospective longitudinal study conducted on the risk factors associated with root caries incidence in a cohort of independently living older adults (n=334). Each subject underwent an oral examination, performed by a single calibrated examiner, to determine the root caries index and other clinical variables. Questionnaires were used to collect data on oral hygiene habits, diet, smoking and alcohol habits and education level. A regression analysis with the outcome variable of root caries experience (no/yes) was conducted.
Results: A total of 334 older adults with a mean age of 69.1 years were examined. 53.3% had at least one filled or decayed root surface. The median root caries index was 3.13 (IQR 0.00, 13.92). The results from the multivariate regression analysis indicated that individuals with poor plaque control (OR 9.59, 95%CI 3.84-24.00), xerostomia (OR 18.49, 95%CI 2.00-172.80), two or more teeth with coronal decay (OR 4.50, 95% CI 2.02-10.02) and 37 or more exposed root surfaces (OR 5.48, 95% CI 2.49-12.01) were more likely to have been affected by root caries.
Conclusions: The prevalence of root caries was high in this cohort. This study suggests a correlation between root caries and the variables poor plaque control, xerostomia, coronal decay (≥2 teeth affected) and exposed root surfaces (≥37). The significance of these risk indicators and the resulting prediction model should be further evaluated in a prospective study of root caries incidence.
Clinical Significance: Identification of risk indicators for root caries in independently living older adults would facilitate dental practitioners to identify those who would benefit most from interventions aimed at prevention.

Hydrological and photochemical influence on dynamics of estuarine bacteria

Os estuários são ecossistemas complexos, onde os processos físicos, químicos e biológicos estão intimamente ligados. A dinâmica bacteriana num estuário reflete a interação e a elevada variação temporal e espacial desses processos. Este trabalho teve como objetivo elucidar as interações entre os processos físicos, fotoquímicos e microbiológicos no sistema estuarino da Ria de Aveiro (Portugal). Para tal, foi realizada uma abordagem inicial no campo, durante a qual as comunidades bacterianas na coluna de água foram caracterizadas em termos de abundância e atividade ao longo de 2 anos. O estudo foi realizado em dois locais distintos, escolhidos por tipificarem as características marinhas e salobras do estuário. Estes locais possuem diferentes hidrodinâmicas, influências fluviais e, quantidade e composição de matéria orgânica. Numa perspectiva mecanicista, foram realizadas simulações laboratoriais no sentido de elucidar a resposta das bactérias à matéria orgânica foto-transformada. As comunidades bacterianas no estuário adaptam-se a diferentes regimes de água doce, desenvolvendo padrões de abundância e atividade distintos nas zonas marinha e salobra. Os elevados caudais dos rios induzem estratificação vertical na zona marinha, promovendo o fluxo de fitoplâncton do mar para o estuário, do bacterioplâncton do estuário para o mar, e estimulam a importação de bactérias aderentes a partículas na zona salobra. O transporte advectivo e os processos de ressuspensão contribuem para aumentar 3 vezes o número de bactérias aderentes a partículas durante os períodos de intensas descargas fluviais. Adicionalmente, a atividade bacteriana no estuário é controlada pela concentração de azoto inerente à variações de água doce. O fornecimento de azoto em associação com a fonte dos substratos bacterianos induzem alterações significativas na produtividade. O padrão de variação vertical de comunidades bacterianas foi distinto nas duas zonas do estuário. Na zona marinha, as bactérias na microcamada superficial (SML) apresentaram taxas de hidrólise mais elevadas, mas menores taxas de incorporação de monómeros e produção de biomassa que na água subjacente (UW), enquanto na zona salobra, as taxas de hidrólise e incorporação foram similares nos dois compartimentos, mas a produtividade foi significativamente mais elevada na SML. Apesar da abundância bacteriana ter sido semelhante na SML e UW, a fração de células aderentes a partículas foi significativamente maior na SML (2-3 vezes), em ambas as zonas do estuário. A integração dos resultados microbiológicos com as variáveis ambientais e hidrológicos mostraram que fortes correntes na zona marinha promovem a mistura vertical, inibindo o estabelecimento de uma comunidade bacteriana na SML distinta da UW. Em contraste, na zona de água salobra, a menor velocidades das correntes fornece as condições adequadas ao aumento da atividade bacteriana na SML. Características específicas do local, tais como a hidrodinâmica e as fontes e composição da matéria orgânica, conduzem também a diferentes graus de enriquecimento superficial de matéria orgânica e inorgânica, influenciando a sua transformação. Em geral, o ambiente da SML estuarina favorece a hidrólise de polímeros, mas inibe a utilização de monómeros, comparativamente com água subjacente. No entanto, as diferenças entre as duas comunidades tendem a atenuar-se com o aumento da atividade heterotrófica na zona salobra. A matéria orgânica dissolvida cromófora (CDOM) das duas zonas do estuário possui diferentes características espectrais, com maior aromaticidade e peso molecular médio (HMW) na zona de água salobra, em comparação com a zona marinha. Nesta zona, a abundância bacteriana correlacionou-se com a350 e a254, sugerindo uma contribuição indireta das bactéria para HMW CDOM. A irradiação do DOM resultou numa diminuição dos valores de a254 e a350, e, em um aumento do declive S275-295 e dos rácios E2:E3 (a250/a365) e SR. No entanto, a extensão de transformações foto-induzidas e as respostas microbianas são dependentes das características iniciais CDOM, inferidas a partir das suas propriedades ópticas. A dinâmica estuarina influencia claramente as atividades heterotróficas e a distribuição dos microorganismos na coluna de água. A entrada de água doce influencia a dinâmica e os principais reguladores das comunidades bacterianas no estuário. Os processos fotoquímicos e microbianos produzem alterações nas propriedades ópticas da CDOM e a combinação desses processos determina o resultado global e o destino da CDOM nos sistemas estuarinos com influência na produtividade nas áreas costeiras adjacente.

Oil hydrocarbon-bacteria interactions in coastal environments

The ability of microorganisms to use oil hydrocarbons as a source of carbon and energy is crucial for environmental oil detoxification. However, there is still a lack of knowledge on fundamental aspects of this process on specific habitats and under different climate scenarios. In the first phase of this work, the culturable fraction of the oil hydrocarbon (OH) degrading bacteria from the sea surface microlayer (SML) of the estuarine system Ria de Aveiro was characterized. In the second phase, the impact of oil contamination on the active bacterial community was studied under climate change scenarios. Pseudomonas emerged as the prevailing genera among OH degrading bacteria in the SML. Moreover, culture-independent methods revealed that the relative abundance and diversity of Gammaproteobacteria, in which Pseudomonas is included, varies along an estuarine gradient of contamination. In order to access the impact of oil contamination on microbial communities under climate change scenarios, an experimental life support system for microcosm experiments (ELLS) was developed and validated for simulation of climate change effects on microbial communities. With the ELSS it is possible to simulate, in controlled conditions, fundamental parameters of the dynamics of coastal and estuarine systems while maintaining community structure in terms of the abundance of the most relevant members of the indigenous bacterial community. A microcosm experiment in which the independent and combined impact of ultraviolet radiation, ocean acidification and oil contamination on microbial communities was conducted. The impact on bacterial communities was accessed with a 16S RNA (cDNA) based barcode pyrosequencing approach. There was a drastic decrease of Desulfobacterales relative abundance after oil contamination under the reduced pH value estimated for 2100, when compared to present values. Since members of this order are known OH degraders, such a significant decrease may have consequences on OH detoxification of contaminated environments under the pH levels of the ocean expected for the future. Metagenome predictions based on the 16S RNA database indicated that several degradation pathways of OH could be affected under oil contamination and reduced water pH. Taken together, the results from this work bring new information on the dynamics of OH degrading bacteria in coastal and estuarine environments under present and future climate scenarios.

Photodynamic inactivation of bacteria by cationic porphyrins : their cellular targets and potential environmental applications

Photodynamic inactivation (PDI) is defined as the process of cell destruction by oxidative stress resulting from the interaction between light and a photosensitizer (PS), in the presence of molecular oxygen. PDI of bacteria has been extensively studied in recent years, proving to be a promising alternative to conventional antimicrobial agents for the treatment of superficial and localized infections. Moreover, the applicability of PDI goes far beyond the clinical field, as its potential use in water disinfection, using PS immobilized on solid supports, is currently under study. The aim of the first part of this work was to study the oxidative modifications in phospholipids, nucleic acids and proteins of Escherichia coli and Staphylococcus warneri, subjected to photodynamic treatment with cationic porphyrins. The aims of the second part of the work were to study the efficiency of PDI in aquaculture water and the influence of different physicalchemical parameters in this process, using the Gram-negative bioluminescent bacterium Vibrio fischeri, and to evaluate the possibility of recycling cationic PS immobilized on magnetic nanoparticles. To study the oxidative changes in membrane phospholipids, a lipidomic approach has been used, combining chromatographic techniques and mass spectrometry. The FOX2 assay was used to determine the concentration of lipid hydroperoxides generated after treatment. The oxidative modifications in the proteins were analyzed by one-dimensional polyacrylamide gel electrophoresis (SDS-PAGE). Changes in the intracellular nucleic acids were analyzed by agarose gel electrophoresis and the concentration of doublestranded DNA was determined by fluorimetry. The oxidative changes of bacterial PDI at the molecular level were analyzed by infrared spectroscopy. In laboratory tests, bacteria (108 CFU mL-1) were irradiated with white light (4.0 mW cm-2) after incubation with the PS (Tri-Py+-Me-PF or Tetra-Py+-Me) at concentrations of 0.5 and 5.0 μM for S. warneri and E. coli, respectively. Bacteria were irradiated with different light doses (up to 9.6 J cm-2 for S. warneri and up to 64.8 J cm-2 for E. coli) and the changes were evaluated throughout the irradiation time. In the study of phospholipids, only the porphyrin Tri-Py+-Me-PF and a light dose of 64.8 J cm-2 were tested. The efficiency of PDI in aquaculture has been evaluated in two different conditions: in buffer solution, varying temperature, pH, salinity and oxygen concentration, and in aquaculture water samples, to reproduce the conditions of PDI in situ. The kinetics of the process was determined in realtime during the experiments by measuring the bioluminescence of V. fischeri (107 CFU mL-1, corresponding to a level of bioluminescence of 105 relative light units). A concentration of 5.0 μM of Tri-Py+-Me-PF was used in the experiments with buffer solution, and 10 to 50 μM in the experiments with aquaculture water. Artificial white light (4.0 mW cm-2) and solar irradiation (40 mW cm-2) were used as light sources.

An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few “model species” on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

Othering, blame and shame when working with people living with HIV

Significant advances in HIV treatment has meant that for the majority of patients with HIV they are able to live a normal lifespan. However, HIV remains a highly stigmatizing disease with the potential to significantly impact on ones social identity and sense of self. This paper draws on data from a qualitative study of interviews with five gay men, to explore the experiences of shame in relation to living with HIV. The paper adopts a psychoanalytic lens to highlight the mechanisms of splitting that may be involved at both a social and individual level, and the experience of shame among the participants. The paper aims to use this research data to supplement our understanding of what may be occurring ‘on the couch’ with patients who are living with HIV.

Mindful Living in Older Age: a Pilot Study of a Brief, Community-Based, Positive Aging Intervention

Although mindfulness-based interventions have been successfully used with older adults, there have been few interventions that, (a) are created specifically for older adults, (b) are delivered in the community, and (c) aim to promote ‘successful aging’ (rather than just treating dysfunction/disorder). To this end, the current study piloted a brief ‘positive aging’ intervention, comprising two 150 minute sessions, with six female older adults living in the community. Data were gathered through focus groups that were interwoven throughout the intervention. Using thematic analysis, four main themes were identified: (a) aging as a mixed blessing; (b) understanding mindfulness; (c) the challenges of mindfulness; and (d) the benefits of mindfulness. Overall, the intervention was successful in introducing participants to mindfulness and potentially forming the basis of a longer term practice. However, the study also highlighted important points on the challenges of practising mindfulness, in relation to which the paper makes recommendations pertaining to the teaching of mindfulness with older adults.

Profiles of ageing in the South of Portugal: education and cognitive functioning in elderly persons living in institutionalized and community contexts

The region of the Algarve shows huge differences between the coastline where population in the urban areas grows, and the inland rural areas, in some cases very isolated, which frequently have high ageing indexes. This general scenario, with an elderly population with very different economic and social conditions, frames the ongoing PhD research designed as a cross-sectional study of an intentional sample of elderly persons. The basic theoretical framework departs from the perspective of developmental psychology of life-span and the model of selection, optimisation and compensation for optimal ageing (Baltes & Baltes, 1990; Freund & Baltes, 2002). The present study is a first step in the analysis of empirical data collected in the PhD sample (N=156; age range 65 to 97 years; M = 80.4 years; SD = 7.2 years). Its purpose is to assess the cognitive functioning of participants, screening for cognitive impairment and examine the relations between the cognitive status of the subjects and a number of selected variables including educational level, age, physical activity and living contexts of the subjects. We accessed the cognitive status of the participants with the Portuguese version of Mini Mental State Examination (MMSE) finding a 10.3% prevalence of positive cases with cognitive impairment. The results also show significant relationships between the cognitive status accessed by the MMSE and educational level, professional qualification, age, living arrangement and activity level of the participants. The relationship verified between educational level and cognitive status of the participants was the largest correlation found in the study with the variability in educational level accounting for 44.8% of the variability in MMSE score. This results points in the same direction of several lines of research that corroborate the strong intercorrelation between education and cognitive functioning in old age.

Bio-removal of toxic metals by metal resistant anaerobic bacteria: molecular characterization and performance studies

Tese de dout., Ciências Biotecnológicas (Biotecnologia Ambiental), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010