Two Novel Dermaseptin-Like Antimicrobial Peptides with Anticancer Activities from the Skin Secretion of Pachymedusa dacnicolor

The dermaseptin antimicrobial peptide family contains members of 27–34 amino acids in length that have been predominantly isolated from the skins/skin secretions of phyllomedusine leaf frogs. By use of a degenerate primer in Rapid amplification of cDNA ends (RACE) PCR designed to a common conserved domain within the 5′-untranslated regions of previously-characterized dermaseptin encoding cDNAs, two novel members of this peptide family, named dermaseptin-PD-1 and dermaseptin-PD-2, were identified in the skin secretion of the phyllomedusine frog, Pachymedusa dacnicolor. The primary structures of both peptides were predicted from cloned cDNAs, as well as being confirmed by mass spectral analysis of crude skin secretion fractions resulted from reversed-phase high-performance liquid chromatography. Chemically-synthesized replicates of dermaseptin-PD-1 and dermaseptin-PD-2 were investigated for antimicrobial activity using standard model microorganisms (Gram-positive bacteria, Gram-negative bacteria and a yeast) and for cytotoxicity using mammalian red blood cells. The possibility of synergistic effects between the two peptides and their anti-cancer cell proliferation activities were assessed. The peptides exhibited moderate to high inhibition against the growth of the tested microorganisms and cancer cell lines with low haemolytic activity. Synergistic interaction between the two peptides in inhibiting the proliferation of Escherichia coli and human neuronal glioblastoma cell line, U251MG was also manifested.

CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS OF LAVANDULA SPP.

Lavenders belong to the family Labiatae and represent some of the most popular medicinal plants of great economic importance. Their essential oils are important for the perfume, cosmetic, flavouring and pharmaceutical industries. However, despite its popularity, and the long tradition of use, biological properties of the various Lavandula species are not yet been well sustained by scientific or clinical studies and some available data being inconclusive and controversial [1]. Although Lavandula spp. have similar ethnobotanical properties, however, chemical composition and therapeutic uses differ from different species and main composition of essential oils showed differences with species and with the region were they grow [1,2,3]. L. stoechas L. subsps. luisieri (Rozeira) Rozeira. L. pedunculata (Mill.) Cav. and L. viridis L’Hér are endemic to the Iberian Peninsula, widespread in the South of Portugal, namely in Alentejo and Algarve. In our work, essential oils from the stems or leaves from wild grown plants of L. luisieri (Alentejo), L. pedunculata (Alentejo) and L. viridis (Algarve), were extracted by hydrodistillation and analyzed by GC-FID. Antimicrobial activity was evaluated by solid diffusion disk assay and minimal inhibitory concentration (MIC) against pathogenic Gram-positive and Gram-negative bacteria and food spoilage fungi.

Bioassays against pinewood nematode: assessment of a suitable dilution agent and screening for bioactive essential oils

Acetone was investigated and found to be an appropriate alternative to Triton X-100 as a solvent of essential oils in bioassays aimed to investigate their effects on pinewood nematode (Bursaphelenchus xylophilus) mortality. Therefore it was used as dilution agent to screen the effectiveness of fifty two essential oils against this pest. Thirteen essential oils were highly effective, resulting in more than 90% pinewood nematode mortality at 2 mg/mL, with six of them resulting in 100% mortality. LC100 values ranged between 0.50 mg/mL and 0.83 mg/mL for the essential oils of Origanum vulgare and Satureja montana, respectively. Essential oils were submitted to gas chromatography and gas chromatography-mass spectrometry analysis and their chemical composition established. Data from essential oils with 100% mortality at 2 mg/mL and other essential oils previously found to have LC100 ≤ 2 mg/mL was combined, their chemical profiles investigated by correspondences analysis plus automatic classification.

ANTIOXIDANT, ANTIMICROBIAL AND TOXICOLOGICAL PROPERTIES OF SCHINUS MOLLE L. ESSENTIAL OILS

Schinus molle L. is commonly known as pink pepper or American pepper, of Anacardiaceae family, from subtropical regions of South America, introduced and naturalized in South Europe, including Portugal. In folk medicine, plant extracts and essential oil has related as having antibacterial, antiviral, antifungal, anti-inflammatory, antitumoral, antispasmodic, analgesic and antidepressive properties. The aim of present study was to evaluate the chemical composition and biological activities of essential oil extracted from leaves and fruits of S. molle. For this purpose, the essential oils were analyzed by gas chromatography (GC/FID) and antioxidant properties were evaluated by the free radical DPPH and by system β-carotene/linoleic acid methods. The antimicrobial activities were screened against pathogenic bacteria and fungi and food spoiling fungi by the disc diffusion assay and minimal inhibitory concentration (MIC) was determined for sensitive strains. Toxicity of essential oils were carried out by the brine shrimp mortality test (EC50) and acute lethal dose (DL50) determination after oral administration in Swiss mice The major components in leaf essential oil were α-phellandrene, β-phellandrene and limonene, while myrcene, α-phellandrene and 1,8-cineole are the main components in the fruit essential oil. The essential oils of leaf and fruit of S. molle showed antioxidant activity through the two mechanisms: the ability to capture free radicals and protection of lipid peroxidation. These oils exhibited also a broad microbial activity spectrum, against pathogenic bacteria Gram-positive and Gram-negative and Candida spp. The fruit essential oil showed high cytotoxicity against Artemia salina. Essential oils of leaves and fruits of S. molle showed significant antioxidant and microbial properties, so the studies continue to clarify more in deep its toxicity, including hepatotoxicity and nephrotoxicity, and to evaluate its medicinal or nutraceutical potential.

Derivation of soil screening values for metals in Portuguese natural soil

The increasing human activity has been responsible by profound changes and a constinuos degradation of the soil compartment in all the European territory. Some European policies are appearing focusing soil’s protection and the management of contaminated sites, in order to recover land for other uses. To regulate the risk assessment and the management of contaminated soils, many European member states adopted soil guideline values, as for example soil screnning values (SSV).These values are particularly useful for the the first tier of the Ecological Risk Assessment (ERA) processes of contaminated sites,especially for a first screening of sites requiring a more site-specific evaluation. Hence, the approriate definition of regional SSVs will have relevant economic impacts in the management of contaminated sites. Portugal is one of European Member States that still lack these soil guideline values. In this context, this study gaves a remarkable contribution in the generation of ecotoxicological data for soil microbiological parameters, terrestrial plants and invertebrates for the derivation of SSVs for uranium (U), cadmium (Cd) and copper (Cu), using a Portuguese natural soil, representative of a dominant type of soil in the Portuguese territory. SSVs were derived based on two methods proposed by the the Technical Guidance Document for Risk Assessment of the European Commission; namely the assessment factor method (AF) and the species sensitivity distribution (SSD) method (with some adaptations). The outputs of both methods were compared and discussed. Further, this study laid the foundation for a deeper reflection about the cut-off (hazard concentration for a given percentage of species - HCps) to be estimated from the SSDs, and to be selected for the derivation of SSVs, with the adequate level of protection. It was proven that this selection may vary for different contaminants, however a clear justification should be given, in each case. The SSvs proposed in this study were for: U (151.4 mg U kg-1dw), Cd (5.6 mg Cd kg-1dw), and Cu (58.5 mg Cu kg-1dw) These values should now be tested for their descriminating power of soils with different levels of contamination. However, this studies clarifies the approach that should be followed for the derivation of SSVs for other metals and organic contaminants, and for other dominant types of Portuguese natural soils.

Aplicação da terapia fotodinâmica no processo de esterilização de sangue

A importância médica do sangue associada ao risco de doenças infeciosas levou a um melhoramento das técnicas de rastreio de patogénicos no sangue doado. No entanto, devido aos períodos de "janela", durante o qual os agentes infeciosos não podem ser detetados, a desinfeção de sangue e seus derivados assume uma importância vital. Considerando que as técnicas convencionais de desinfeção (tratamento com solvente-detergente ou irradiação com UV ou radiação gama) pode ser empregue em concentrados de plasma ou de proteínas, o efeito colateral associado aos respetivos tratamentos não permite a sua utilização em frações celulares. Consequentemente, é necessário o desenvolvimento de uma nova alternativa eficaz para inativar microrganismos em sangue. Uma boa estratégia que merece ser considerada baseia-se na terapia fotodinâmica antimicrobiana (aPDT). aPDT envolve a interação entre a luz e um fotossensibilizador (PS) na presença de oxigénio molecular. Esta interação produz espécies reativas de oxigénio (ROS), que causam danos oxidativos às moléculas microbianas necessárias à sobrevivência do microrganismo. Em alguns países, esta metodologia já está aprovada para descontaminação de plasma, utilizando azul de metileno ou psoraleno como PSs. O objetivo deste estudo foi avaliar a adequação de de estrutura do tipo ftalocianina (Pc) e porfirina (Por) para desinfeção fotodinâmica de hemoderivados. Plasma e sangue total foram infetados com 108 unidades formadoras de colónias (CFU) / mL de Escherichia coli e após incubação com os derivados Pc e Por em estudo, expostos respetivamente a luz vermelha ou a luz branca com uma irradiância de 150 W/m2durante 270 min. As concentrações de E. coli viáveis foram determinadas a 0, 30, 60, 90, 180 e 270 min e comparadas com as obtidas nos controlos claro (amostras irradiadas na ausência de PS) e controlos escuro (amostras incubadas com PS mas não irradiadas). O efeito do tratamento aPDT nas células do sangue (glóbulos vermelhos e brancos) também foi avaliado. Os resultados obtidos mostram que, em todos os componentes do sangue, a Por em estudo é mais eficaz na inativação de E. coli que o derivado Pc. Após o tratamento aPDT, o número de células vermelhas e brancas no sangue é semelhante aos valores observados nas amostras de controlo. A eficiente inativação de células de E. coli e a ausência de efeito sobre as células de sangue transformam os derivados porfirínicos e ftalocianinas potenciais candidatos a serem utilizados com fotossensibilizadores na desinfeção fotodinâmica de produtos derivados do sangue.

Antimicrobial resistance and synergy in herbal medicine

Antimicrobial resistance (AMR) is a serious and growing threat to human health. The development of new antibiotics is limited and slow. The tradition of synergy in herbal medicine is being used as a source of research ideas. A literature review of antimicrobial research and plant synergy published in a five year period was carried out using online databases. The in vitro findings were that most of the research reported synergy both within plants and between plants and antibiotics. Whole plant extracts and combinations of compounds were shown to be more effective antimicrobials than isolated constituents. The discussion highlights that the in vitro herbal research findings are difficult to apply to practice and aren’t progressing to clinical trials. Collaborative, innovative, inter-disciplinary clinical research is recommended.

Screening for biological activities with application in aquaculture in halophytes from the Algarve coastline

Infectious diseases often hamper the production of aquatic organisms in aquaculture systems, causing economical losses, environmental problems and consumer safety issues. The conventional way aquaculture producers had to control pathogens was by means of synthetic antibiotics and chemicals. This procedure had consequences in the emergence of more resilient pathogens, drug contamination of seafood products and local ecosystems. To avoid the repercussions of antibiotic use, vaccination has greatly replaced human drugs in western fish farms. However there is still massive unregulated antibiotic use in third world fish farms, so less expensive therapeutic alternatives for drugs are desperately needed. An alternative way to achieve disease control in aquaculture is by using natural bioactive organic compounds with antibiotic, antioxidant and/or immunostimulant properties. Such diverse biomolecules occur in bacteria, algae, fungi, higher plants and other organisms. Fatty acids, nucleotides, monosaccharides, polysaccharides, peptides, polyphenols and terpenoids, are examples of these substances. One promising source of bioactive compounds are salt tolerant plants. Halophytes have more molecular resources and defence mechanisms, when compared with other tracheophytes, to deal with the oxidative stresses of their habitat. Many halophytes have been used as a traditional food and medical supply, especially by African and Asian cultures. This scientific work evaluated the antibiotic, antioxidant, immunostimulant and metal chelating properties of Atriplex halimus L., Arthrocnemum macrostachyum Moric., Carpobrotus edulis L., Juncus acutus L. and Plantago coronopus L., from the Algarve coast. The antibiotic properties were tested against Listonella anguillarum, Photobacterium damselae piscicida and Vibrio fischeri. The immunostimulant properties were tested with cytochrome c and Griess assays on Sparus aurata head-kidney phagocytes. J. acutus ether extract inhibited the growth of P. damselae piscicida. A. macrostachyum, A. halimus, C. edulis, Juncus acutus and P. coronopus displayed antioxidant, copper chelating and iron chelating properties. These plants show potential as sources of bioactive compounds with application in aquaculture and in other fields.

Development of chitosan packaging films with carvacrol and grape seed extract as antimicrobial and antioxidant agents

In order to produce packaging films with a broad spectrum of action on microorganisms, the effect of two antimicrobial (AM) to be included in the films, carvacrol and GSE were studied separately on different microorganisms. Carvacrol was more effective against the grampositive bacteria than against the gram-negative bacterium. GSE was not effective against yeast. Subsequently, a search for optimal combinations of carvacrol, GSE and the addition of chitosan (as a third component with film forming properties) was carried out. Response surface analysis showed several synergetic effects and three optimal AM combinations (OAMC) were obtained for each microorganism. The experimental validation confirmed that the optimal solutions found can successfully predict the response for each microorganism. The optimization of mixtures of the three components, but this time, using the same concentration for all microorganisms, was also studied to obtain an OAMC with wide spectrum of activity. The results of the response surface analysis showed several synergistic effects for all microorganisms. Three OAMC, OAMC-1, OAMC-2, OAMC-3, were found to be the optimal mixtures for all microorganisms. The radical scavenging activity (RSA) of the different agents was then compared with a standard antioxidant (AOX) BHT, at different concentrations; as also at the OAMC. The RSA increased in the following order: chitosan

Screening for success in a visual arts program.

Abstract: Little research has been directed towards determining means of predicting success in visual arts programs. Therefore, this study attemps to profile a typical successful student in a visual arts program, namely the Illustration & Design program at Dawson College. To this end, questionnaires, designed by the researcher, served to investigate the students' reasons for choosing the program as well as provide demographic data. In addition, students' personality types were investigated by means of the online Sternberg & Wagner Thinking Styles Inventory (SWTSI) questionnaire. Using the SPSS statistical software, an analysis was done to determine whether students who offer intrinsically motivated reasons for applying to the Illustration & Design program are those who also demonstrate greater academic success. Furthermore, grounding this study in Sternberg's theory of mental self governance, students' college grades were correlated to their personality type to determine if Type I personality types perform better academically than Type II or Type III (Zhang, 2005), The participants consisted of three cohorts (128 students form semester 1, 3 and 5) of the Illustration & Design program, as well as two comparison groups, one from the Fine Arts program (24 students), and another from the Business Administration program, a non-visual arts program at Dawson College (20 students).||Résumé: Les recherches portant sur l'identification de moyens qui permettent de prédire la réussite dans les programmes d'arts plastiques sont très rares. Par conséquent, cette étude tente de dresser le profil de l'élève type qui réussit dans un programme d'arts visuels, à savoir le programme Illustration & Design au Collège Dawson. À cette fin, des questionnaires conçus par le chercheur ont servi à déterminer les raisons pour lesquelles l'élève a choisi ce programme et ont permis de fournir des données démographiques. En outre, les étudiants ont été catégorisés par type de personnalité au moyen du questionnaire Sternberg & Wagner Thinking Styles Inventory (SWTSI). Grâce au logiciel statistique SPSS, une analyse a été effectuée afin de déterminer si les élèves dont la motivation comptait beaucoup dans leur choix du programme Illustration & Design étaient aussi ceux qui affichaient un taux de réussite plus élevé. En outre, en s'appuyant sur la Théorie d'autonomie de gestion mentale de Sternberg, cette étude avait pour but de corréler les résultats scolaires des élèves à leur personnalité afin de déterminer si les étudiants du Type de personnalité I avaient de meilleurs résultats scolaires que ceux de Type II et de Type III (Zhang, 2005). Les participants étaient composés de trois cohortes (128 étudiants des 1er, 3e et 5e semestres) du programme Illustration et Design ainsi que de deux groupes témoins, un groupe de 24 élèves du programme de Techniques de l'Administration, programme en dehors des arts visuels.

Antimicrobial activity of essential oils isolated from Portuguese endemic species of Thymus

Aims: Thymus species are wild species mostly found in the arid lands of Portugal. Possible antimicrobial properties of Thymus essential oils have been investigated. The chemical composition of the essential oils and the antimicrobial activity of Thymus mastichina (L) L. subsp. mastichina , T. camphoratus and T. lotocephalus from different regions of Portugal were analysed. Methods and Results: Hydrodistillation was used to isolate the essential oils and the chemical analyses were performed by gas chromatography (GC) and GC coupled to mass spectrometry. The antimicrobial activity was tested by the disc agar diffusion technique against Candida albicans , Escherichia coli , Listeria monocytogenes , Proteus mirabilis , Salmonella spp. and Staphylococcus aureus . Pure linalool, 1,8-cineole and a mixture (1:1) of these compounds were included. Linalool, 1,8-cineole or linalool/1,8-cineole and linalool/1,8-cineole/linalyl acetate were the major components of the essential oils, depending on the species or sampling place. The essential oils isolated from the Thymus species studied demonstrated antimicrobial activity but the micro-organisms tested had significantly different sensitivities. Conclusions: The antimicrobial activity of essential oils may be related to more than one component. Significance and Impact of the Study: Portuguese endemic species of Thymus can be used for essential oil production for food spoilage control, cosmetics and pharmaceutical use. Further studies will be required to elucidate the cell targets of the essential oil components.

Sustained drug use changes following hepatitis C screening and counseling among recently infected persons who inject drugs: a longitudinal study

BACKGROUND: Notification of hepatitis C virus (HCV) positive status is known to have short-term impacts on subsequent alcohol, drug use and injection behaviors among persons who inject drugs (PWID). It remains to be established whether post-screening behavioral changes extend over time for PWID and whether screening test notification has behavioral impacts among HCV-negative PWID. This study sought to longitudinally assess substance use and injection behaviors after HCV status notification among HCV seroconverters and HCV-negative PWID. METHODS: Initially HCV-seronegative PWID (n = 208) were followed prospectively between 2004 and 2011 in Montreal, Canada. Semi-annual screening visits included blood sampling and an interview-administered questionnaire assessing substance use and injection behaviors. Multivariable generalized estimating equation analyses were conducted to assess substance use and behavior changes over time and compare changes between HCV seroconverters and HCV-seronegative participants while adjusting for baseline characteristics. RESULTS: Of the 208 participants (83% male; mean age, 34.7 years, mean follow-up time, 39 months), 69 (33.2%) seroconverted to HCV. A linear decrease in syringe sharing behavior was observed over time after HCV and status notification, whereas a 10% decrease for each additional 3 months of follow-up was observed for injection cocaine and heroin use among HCV seroconverters but not among HCV-seronegative PWID (P < .05). No significant changes were observed in alcohol use. CONCLUSIONS: Our results indicate that notification of HCV-positive status is associated with reduced injection drug use among seroconverters. Among PWID deemed seronegative after screening, there is no sustained trend for change in risk behavior.

Screening of process conditions for the production of biogas from diluted organic waste streams using microreactors

Dissertação de Mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Lancefield group C and G streptococci in human infection : molecular typing, virulence and antimicrobial susceptibility

Tese de doutoramento, Ciências e Tecnologias da Saúde (Microbiologia), Universidade de Lisboa, Faculdade de Medicina, 2014