Gold or silver nanoparticles decorating superparamagnetic calcium ferrite nanoparticles for application in SERS

In this work, we report the synthesis of Ag and Au nanoparticles capped with either cysteamine or cysteine. Purification of these NPs turned out to originate irreversible aggregation, so that the coupling of NH2 groups from Au (or Ag) nanoparticles to OH groups of magnetic calcium ferrite (CaFe2O4) nanoparticles (MNPs) would not work as expected. Therefore, naked metallic Ag or Au nanoparticles were produced and connection to calcium ferrite was performed by first attaching cysteine to the MNPs and then using the resulting SH pending groups to interact with the metallic surface.Financial support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2013).info:eu-repo/semantics/publishedVersio

The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states

Chlorine is the most commonly used agent for general disinfection, particularly for microbial growth control in drinking water distribution systems. The goals of this study were to understand the effects of chlorine, as sodium hypochlorite (NaOCl), on bacterial membrane physicochemical properties (surface charge, surface tension and hydrophobicity) and on motility of two emerging pathogens isolated from drinking water, Acinetobacter calcoaceticus and Stenotrophomonas maltophilia. The effects of NaOCl on the control of single and dual-species monolayer adhered bacteria (2 h incubation) and biofilms (24 h incubation) was also assessed. NaOCl caused significant changes on the surface hydrophobicity and motility of A. calcoaceticus, but not of S. maltophilia. Planktonic and sessile S. maltophilia were significantly more resistant to NaOCl than A. calcoaceticus. Monolayer adhered co-cultures of A. calcoaceticus-S. maltophilia were more resilient than the single species. Oppositely, dual species biofilms were more susceptible to NaOCl than their single species counterparts. In general, biofilm removal and killing demonstrated to be distinct phenomena: total bacterial viability reduction was achieved even if NaOCl at the higher concentrations had a reduced removal efficacy, allowing biofilm reseed. In conclusion, understanding the antimicrobial susceptibility of microorganisms to NaOCl can contribute to the design of effective biofilm control strategies targeting key microorganisms, such as S. maltophilia, and guarantying safe and high-quality drinking water. Moreover, the results reinforce that biofilms should be regarded as chronic contaminants of drinking water distribution systems and accurate methods are needed to quantify their presence as well as strategies complementary/alternative to NaOCl are required to effectively control the microbiological quality of drinking water.This work was financially supported by: Project POCI-01-0145-FEDER-006939 (Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT - Fundação para a Ciência e a Tecnologia/MEC: Project POMACEA–Inn-INDIGO/0001/2014, SFRH/BD/103810/2014 and SFRH/BPD/81982/2011

Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress

This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10mg l1 of free chlorine for 10min, an increased shear stress (a fluid velocity of 1.5m s1 for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.This work was the result of the projects: UID/EQU/00511/2019 – Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE funded by national funds through FCT/MCTES (PIDDAC); POCI-01-0145-FEDER-030219; POCI-01-0247-FEDER-035234; POCI-01-0247-FEDER-033298 - funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES; NORTE-01-0145-FEDER-000005 – LEPABE-2-ECO-INNOVATION, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Grant attributed by Portuguese Foundation for Science and Technology – FCT – to Inês Gomes (SFRH/BD/103810/2014) and to Manuel Simoes (SFRH/BSAB/150379/2019).info:eu-repo/semantics/publishedVersio

Effect of sodium hypochlorite on bacteria isolated from drinking water

Biofilm formation inside drinking water distribution systems (DWDS) constitutes one of the major microbial problems in the distribution of safe water. Biofilms in DWDS can act as a reservoir of pathogenic microorganisms and consequently constitute a threat to public health. Therefore, the control of biofilm development inside the pipes of DWDS is a concern for drinking water companies being the use of chlorine one of the most commonly used disinfecting strategies to avoid microbial growth. The aim of this work was to understand the effects of sodium hypochlorite (NaOCl) at residual and high doses against biofilms formed by two bacteria isolated from a DWDS (Acinectobacter calcoaceticus and Stenotrophomonas maltophilia, two emergent pathogens) on polyvinyl chloride. The NaOCl effects were evaluated in bacterial membrane properties and in biofilm cohesion. NaOCl demonstrated action on the bacterial membrane, particularly on the surface hydrophobicity of A. calcoaceticus and on the surface charge of S. maltophilia. NaOCl also caused motility inhibition of A. calcoaceticus. The use of residual concentrations to control bacterial adhesion was inefficient. High concentrations were able to reduce significantly the number of adhered bacteria. However, mature biofilms formed by A. calcoaceticus and S. maltophilia were highly resistant to the combination of chemical and mechanical stresses. In conclusion, the overall results demonstrated a significant action of NaOCl on A. calcoaceticus and S. maltophilia planktonic cells and monolayer adhered cells. However, their mature biofilms were not controlled even when high biocide doses and mechanical stress were applied alone and in combination

Synthetic biology approaches to engineer polyphenols microbial cell factories

Polyphenols are secondary metabolites isolated from plants that can be divided into flavonoids, stilbenoids, curcuminoids, coumarins, polyphenolic amides and lignans. These exhibit diverse biological and potential therapeutic activities including antioxidant, anti-inflammatory and anticancer, among others. Despite all this potential, extracting polyphenols from plants is not straightforward given the low yields of the process. The extracted amounts are not sufficient to respond to the increasing demand for polyphenols, the process is expensive and unfriendly for the environment. Hence, developing microbial cell factories to effectively produce polyphenols arises as an attractive way to address the mentioned limitations and produce high amounts of these compounds. Advances in the metabolic engineering and synthetic biology fields have been key in the design of efficient and robust microbial cell factories, mainly due to the development of proper molecular biology tools, as well as to the unravelling of new enzymes in plants or other organisms to better engineer such heterologous pathways. Several hosts have been explored as potential polyphenols microbial cell factories. However, there is still a long way before this production at an industrial scale can become a reality. The perspectives and current challenges resulting from these developments will be discussed.info:eu-repo/semantics/publishedVersio

Antimicrobial Activity and Chemical Composition of the Essential Oils of Portuguese Foeniculum vulgare Fruits

The aim of this study was to investigate the chemical composition and antimicrobial activity of essential oils obtained by hydrodistillation from fruits of six fennel accessions collected from wild populations occurring in the centre and south of Portugal. Composition of essential oils was established by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The obtained yields of the essential oils were found to vary greatly in the range of 1.1 to 2.9% (v/w) and the chemical composition varied with the region of collection. A total of 16 compounds were identified. The main compounds were fenchone (16.9 – 34.7%), estragole (2.5 – 66.0%) and trans-anethole (7.9 – 77.7%). The percentages of these three main compounds were used to determine the relationship between the different oil samples and to group them into four different chemotypes: anethole/fenchone; anethole; estragole and anethole/estragole. Antifungal activity of essential oils was evaluated against six food spoilage fungi: Aspergillus niger, A. japonicus, A. oryzae, Fusarium oxysporum, Rhizophus oryzae and R. stolonifer. Antibacterial activity was assessed against three Gram-positive strains: Enterococcus faecalis ATCC 29212, Staphylococcus epidermidis ATCC 12228 and S. aureus ATCC 28213; and against six Gram-negative strains: Escherichia coli ATCC 25922; Morganella morganii LFG 08; Proteus mirabilis LFG 04; Salmonella enteritidis LFG 05; S. entiritidis serovar typhimurium LFG 06 and Pseudomonas aeruginosa ATCC 27853 by the disc diffusion agar method; the minimal inhibitory concentration (MIC) was determined using the broth macro-dilution method. The MIC values varied from 62.5 (E. coli ATCC 25922) to 2000 μg/mL (P. aeruginosa ATCC 27853)

A procedure to harmonize the hydrodynamic force during microbial cultivation in shaking flasks

The following material is available online at: https://journals.asm.org/doi/10.1128/jmbe.00099-23Shake flask cultivation is a routine technique in microbiology and biotechnology laboratories where cell growth can be affected by the hydrodynamic conditions, which depend on the agitation velocity, shaking diameter, and shake flask size. Liquid agitation is implemented inherently to increase aeration, substrate transfer to the cells, and prevent sedimentation, disregarding the role of hydrodynamics in microbial growth and metabolism. Here, we present a simple approach to help standardize the hydrodynamic forces in orbital shakers to increase the experimental accuracy and reproducibility and give students a better knowledge of the significance of the agitation process in microbial growth.This research was funded by LA/P/0045/2020 (ALiCE), UIDB/00511/2020, and UIDP/00511/2020 (LEPABE), funded by national funds through FCT/MCTES (PIDDAC); UIDB/04469/2020 (CEB) and LABBELS—Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020; Germirrad-POCI-01–0247-FEDER-072237, funded by FEDER funds through COMPETE2020–Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES.info:eu-repo/semantics/publishedVersio

Dyspareunia in HIV-positive and HIV-negative middle-aged women: a cross-sectional study

To evaluate whether dyspareunia is associated with HIV status in menopausal women and also to assess which factors are associated with dyspareunia in a group of HIV-positive menopausal women. A cross-sectional study was conducted with 178 HIV-negative and 128 HIV-positive women aged 40-60 years. The Short Personal Experiences Questionnaire (SPEQ) was used to collect data. Sociodemographic, clinical, behavioural and reproductive factors were evaluated, as well as factors related to the HIV infection. Dyspareunia was defined as pain during intercourse. A bivariate analysis and Poisson multiple regression analysis were performed. Overall, 41.4% of the HIV-positive women reported dyspareunia compared with 34.8% of the HIV-negative women (p=0.242). In the HIV-positive women, bivariate analysis revealed an association between dyspareunia and having a steady partner (p=0.047); the woman's partner having undergone HIV testing (p=0.020); vaginal dryness (p<0.001); muscle/joint pain (p=0.021); physical/emotional violence (p=0.049); urinary incontinence (p=0.004); and the use of lamivudine/zidovudine (p=0.048). The Poisson multiple regression analysis found an association between dyspareunia and vaginal dryness (prevalence ratio (PR)=1.96, 95% CI 1.10 to 3.50, p=0.023) and urinary incontinence (PR=1.86, 95% CI 1.06 to 3.27, p=0.031). Dyspareunia was common in this group of HIV-positive women and was associated principally with vaginal dryness and urinary incontinence. The importance of treating dyspareunia within the context of sexual health in this group of women should be emphasised and appropriate management of this issue may reduce the likelihood of lesions on the vaginal wall, which may act as a portal of entry for other infections.To evaluate whether dyspareunia is associated with HIV status in menopausal women and also to assess which factors are associated with dyspareunia in a group of HIV-positive menopausal women. A cross-sectional study was conducted with 178 HIV-negativ416FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2010/06037-