Investigação sobre a capacidade de sobrevivência durante o inverno na ilha Terceira, Açores, de Istocheta aldrichi (Mesnil) (Diptera: Tachinidae) um parasitóide de Popillia japonica Newman (Coleoptera: Scarabaeidae).

A study of diapause in the parasitic fly Istocheta aldrichi (Diptera: Tachinidae) was undertaken to help investigate the possibility of its establishment in Terceira as a biological control agent of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). It was concluded that pupae should be imported from the USA only when they are almost ready to emerge, and to optimise rearing conditions there to increase emergence percentages. Conditions are not ideal for its development in Terceira, as this univoltine parasitoid has a high pupal mortality both in laboratory cultures and outdoors during the overwintering period. These studies should continue until I. aldrichi has become established in the Azores

The effects of a biocide and a surfactant on the detachment of Pseudomonas fluorescens from glass surfaces

Application of antimicrobial chemicals is a general procedure in the cleaning and disinfection of food-contacting surfaces. Adhesion to glass surfaces and chemically induced detachment of Pseudomonas fluorescens ATCC 13525T were studied in situ, under flow conditions, in a well-controlled parallel plate flow chamber (PPFC). Ortho-phthalaldehyde (OPA) and cetyltrimethyl ammonium bromide (CTAB) were applied separately, at several concentrations, to attached bacteria and their subsequent detachment was monitored. Following treatments the remaining adhered bacteria were characterized in terms of viability and cell size. Simultaneously, the planktonic cell surface was characterized in order to correlate PPFC results with thermodynamic approaches for adhesion evaluation, and surface free energy of chemically treated cells with adhesion strength. About 2.8 × 106 cells/cm2 adhered to the glass surface after 30 min of bacterial flow, although thermodynamic analyses evidenced unfavourable adhesion. The independent application of OPA and CTAB promoted bacterial detachment to a small extent (16% of total cells). The remaining adhering bacteria were totally non-viable for OPA ≥ 0.75 mM and CTAB ≥ 0.25 mM, showing a lack of correlation between bacterial viability and detachment. The cellular size decreased as attachment proceeded and with chemical treatment. Both chemicals altered the cell surface properties, increasing the cell-glass adhesion strength, and promoting the emergence of polar characteristics. The overall results emphasize that OPA and CTAB were markedly ineffective in removing glass-attached P. fluorescens, demonstrating that bacteria can be non-viable but remain strongly attached to the adhesion surface.Fundação para a Ciência e a Tecnologia (FCT) - Project CHEMBIO – POCI/BIO/61872/2004; SFRH/BD/ 31661/2006; SFRH/BPD/20582/2004

Serratia plymuthica dairy industry isolates and their antimicrobial metabolites impact on pathogens

Background and aims: Phenotypical differences from interstrain variability is a known phenomenon, assessed in this study for V4 and Y S. plymuthica isolates, particularly at antimicrobial metabolites production and effect on pathogens biofilms. Methods: Isolates were biochemically characterized, specific growth rates in Tryptic Soy/Skim Milk Broth determined, and the antimicrobial activity of cell-free spent media tested on Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Bacillus cereus and Escherichia coli lawns. Their biofilm removal capacity was assessed on 24h pathogens biofilms, through 30min treatments, and biofilm formation impairment ability by 10min substratum pre-conditioning. Results: These siderophores and quorum-sensing inhibitors releasers isolates showed different protease expression and growth rates in both media. Droplets of isolates cell-free spent TSB presented positive inhibitory capacity. V4-SMB biofilms had equal mass and specific respiratory activity values, while low mass Y biofilms were extremely active. Its biofilms in TSB showed the opposite, being V4 biofilms particularly metabolically active and thicker. All cell-free SMB/TSB supernatants pre-conditioning led to a steep reduction of the respiratory activity of S. aureus, E. coli and S. epidermidis biofilms later formed, though increasing their mass. Biofilms treatment with any supernatant similarly decreased their mass. L. monocytogenes, was particularly affect by all, S.aureus by TSB/SMB V4-spent, and S. epidermidis by SMB V4-spent. Conclusions: S. plymuthica isolates registered different biofilm formation ability and cell-free spent TSB/SMB antimicrobial activity. An understanding of mechanisms underlying antimicrobials actionmode in single/mixed Gram positive/negative species biofilms is sought

Geração de cenários de mudança de uso do solo na Amazônia Legal brasileira em função do agronegócio e da aplicação de políticas públicas.

As mudanças climáticas podem afetar a biodiversidade, da mesma forma, a contínua perda da biodiversidade pode, por sua vez, afetar a regulação do clima apresentando graves consequências para o desenvolvimento sustentável e o bem-estar humano. As mudanças no uso da terra, o desmatamento e as mudanças climáticas impactam fortemente o ecossistema da floresta amazônica ameaçando sua resiliência e a sustentabilidade de muitas atividades humanas. Este trabalho descreve a utilização da modelagem dinâmica para gerar cenários de mudança de uso da terra da Amazônia Legal Brasileira, buscando elaborar cenários de mudança de uso/cobertura em função do Agronegócio (agricultura, pastagem e reflorestamento) e considerando o desflorestamento legal, ocasionado pela exploração econômica do território. Os cenários de referência foram baseados nos cenários de desenvolvimento SSP1P, SSP5S e SSP5P do IPCC adapatados a situação de cada estado da Amazônia Legal e considerando-se as políticas brasileiras de desenvolvimento durável, tais como implantação do Plano ABC (Agricultura de Baixo Carbono), código florestal, dentre outras. Este trabalho, ainda em desenvolvimento, é parte do projeto ROBIN ? Role of Biodiversity in Climate Cahnge Mitigation ? financiado pela Comissão Europeia (FP7 ENV. 2011.2.1.4 -1: potencial de biodiversidade e ecossistemas para a mitigação das alterações climáticas), cujo objetivo geral é melhorar a compreensão sobre as relações da biodiversidade com o processo de mitigação de mudança climática

Sodium dodecyl sulfate allows the persistence and recovery of biofilms of Pseudomonas fluorescens formed under different hydrodynamic conditions

The effect of the anionic surfactant sodium dodecyl sulfate (SDS) on Pseudomonas fluorescens biofilms was investigated using flow cell reactors with stainless steel substrata, under turbulent (Re=5200) and laminar (Re=2000) flow. Steady-state biofilms were exposed to SDS in single doses (0.5, 1, 3 and 7 mM) and biofilm respiratory activity and mass measured at 0, 3, 7 and 12 h after the SDS application. The effect of SDS on biofilm mechanical stability was assessed using a rotating bioreactor. Whilst high concentrations (7 mM) of SDS promoted significant biofilm inactivation, it did not significantly reduce biofouling. Turbulent and laminar flow-generated biofilms had comparable susceptibility to SDS application. Following SDS exposure, biofilms rapidly recovered over the following 12 h, achieving higher respiratory activity values than before treatment. This phenomenon of posttreatment recovery was more pronounced for turbulent flow-generated biofilms, with an increase in SDS concentration. The mechanical stability of the biofilms increased with surfactant application, except for SDS concentrations near the critical micellar concentration, as measured by biofilm removal due to an increase in external shear stress forces. The data suggest that although SDS exerts antimicrobial action against P. fluorescens biofilms, even if only partial and reversible, it had only limited antifouling efficacy, increasing biofilm mechanical stability at low concentrations and allowing significant and rapid recovery of turbulent flow-generated biofilms.Fundação para a Ciência e a Tecnologia (FCT

Dirac and Majorana heavy neutrinos at LEP II

The possibility of detecting single heavy Dirac and Majorana neutrinos at LEP II is investigated for heavy neutrino masses in the range $M_N=(\sqrt s/2, \sqrt s)$. We study the process $e^+e^- \longrightarrow \nu_{\ell} \ell q_i \bar q_j$ as a clear signature for heavy neutrinos. Numerical estimates for cross sections and distributions for the signal and the background are calculated and a Monte Carlo reconstruction of final state particles after hadronization is presented.Comment: 4 pages, 8 figure