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

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

Coaggregating Delftia acidovorans facilitates the metabolic activity of partner bacteria in drinking water biofilms

Although bacterial coaggregation has already been identified as a key mechanism in the multispecies biofilms development in diverse environments, little is known about this highly specific type of cell-cell interaction in aquatic systems. In this study, a strain of Delftia acidovorans isolated from drinking water (DW) and previously described with coaggregation ability, was studied for its role in biofilm development. Single and dual-species biofilms, of D. acidovorans and the DW representative bacteria Citrobacter freundii and Pseudomonas putida, were grown in 96-well microtiter plates and characterized in terms of metabolic activity. In addition, to prove that D. acidovorans can facilitate the metabolic activity of other bacteria, single biofilms were formed in the presence of D. acidovorans cell-free supernatant (CFS). The metabolic activity was higher when comparing single with dual-species biofilms. Furthermore, in the presence of CFS, it was evident an increase in the metabolic activity of C. freundii and P. putida biofilms. These results suggest the production of extracellular metabolites by D. acidovorans, that possibly act as public goods. That said, the presence of coaggregating species, namely D. acidovorans, in biofilms appears to create a functional cooperative microbial community, providing a favorable metabolic opportunity for partner bacteria.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 by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechnaical Systems, LA/P/0029/2020; UIDB/04033/2020 (CITAB); Project 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; project HealthyWaters (NORTE-01- 0145-FEDER-000069)- NORTE 2020/ERDF; and the FCT grant (2020.04773.BD).info:eu-repo/semantics/publishedVersio

Elemental Composition of Commercial Herbal Tea Plants and Respective Infusions

Funding Information: Funding: This work received funding support from national funds from Fundação para a Ciência e a Tecnologia, I.P. (FCT), Portugal, through the research units UIDB/04035/2020 (GeoBioTec) and UIDB/00239/2020 (CEF). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.This study evaluated the elemental composition of 25 herbal tea plants commonly used in infusions by Portuguese consumers and the contribution to the elemental daily intake of some essential elements. Hydrocotyle asiatica (L.), Matricaria chamomilla (L.), and Melissa officinalis (L.) samples are a rich source of K with around 6.0 mg g−1 while the Asteraceae Silybum marianum (L.) and Echinacea angustifolia (DC.) exhibited 4.9 and 5.6 mg g−1 Ca, respectively. The highest concentrations of S and Zn were noted in Hydrocotyle asiatica (L.), while the highest concentration of Sr was found in Cassia angustifolia (Vahl.). In general, a large variability in the concentrations among different families and plant organs had been observed, except Cu with levels around 30 µg g−1. The principal component analysis (PCA) showed positive correlations between Zn and S and Sr and Ca, also revealing that Hydrocotyle asiatica (L.), Echinacea angustifolia (DC.), Silybum marianum (L.), and Cassia angustifolia (Vahl.) samples, stands out about all other samples regarding the enrichment of macro and micronutrients. The elemental solubility of macronutrients in the infusion is greater than the micronutrient solubility, despite the contribution to the recommended daily intake was weak. As a whole, Cynara scolymus (L.) and Hibiscus sabdariffa (L.) are the species with the best elemental solubilities, followed by Hydrocotyle asiatica (L.). No harmful elements, such as As and Pb, were observed in both the raw material and the infusions.publishersversionpublishe

Elemental Composition of Commercial Herbal Tea Plants and Respective Infusions

This study evaluated the elemental composition of 25 herbal tea plants commonly used in infusions by Portuguese consumers and the contribution to the elemental daily intake of some essential elements. Hydrocotyle asiatica (L.), Matricaria chamomilla (L.), and Melissa officinalis (L.) samples are a rich source of K with around 6.0 mg g-1 while the Asteraceae Silybum marianum (L.) and Echinacea angustifolia (DC.) exhibited 4.9 and 5.6 mg g-1 Ca, respectively. The highest concentrations of S and Zn were noted in Hydrocotyle asiatica (L.), while the highest concentration of Sr was found in Cassia angustifolia (Vahl.). In general, a large variability in the concentrations among different families and plant organs had been observed, except Cu with levels around 30 g g-1. The principal component analysis (PCA) showed positive correlations between Zn and S and Sr and Ca, also revealing that Hydrocotyle asiatica (L.), Echinacea angustifolia (DC.), Silybum marianum (L.), and Cassia angustifolia (Vahl.) samples, stands out about all other samples regarding the enrichment of macro and micronutrients. The elemental solubility of macronutrients in the infusion is greater than the micronutrient solubility, despite the contribution to the recommended daily intake was weak. As a whole, Cynara scolymus (L.) and Hibiscus sabdariffa (L.) are the species with the best elemental solubilities, followed by Hydrocotyle asiatica (L.). No harmful elements, such as As and Pb, were observed in both the raw material and the infusionsinfo:eu-repo/semantics/publishedVersio

Different genomic changes underlie adaptive evolution in populations of contrasting history

Funding Information: This work was supported by Portuguese National Funds through “Fundac¸ão para a Ciência e a Tecnologia” (projects PTDC/ BIA-BEC/098213/2008, PTDC/BIA-BIC/2165/2012 and cE3c Unit FCT funding UID/BIA/00329/2013, grants SFRH/BD/ 60734/2009 to I.F. and SFRH/BPD/86186/2012 to P.S.). We thank Miguel Lopes-Cunha for help in the laboratory, Francisco Pina-Martins for help with computing, Josiane Santos and Ana Sofia Quina for discussions, and Mauro Santos and Anthony Long for advice on the study and comments on the manuscript. We also thank the three anonymous reviewers for their constructive suggestions.Experimental evolution is a powerful tool to understand the adaptive potential of populations under environmental change. Here, we study the importance of the historical genetic background in the outcome of evolution at the genomewide level. Using the natural clinal variation of Drosophila subobscura, we sampled populations from two contrasting latitudes (Adraga, Portugal and Groningen, Netherlands) and introduced them in a new common environment in the laboratory. We characterized the genome-wide temporal changes underlying the evolutionary dynamics of these populations, which had previously shown fast convergence at the phenotypic level, but not at chromosomal inversion frequencies. We found that initially differentiated populations did not converge either at genome-wide level or at candidate SNPs with signs of selection. In contrast, populations from Portugal showed convergence to the control population that derived from the same geographical origin and had been long-established in the laboratory. Candidate SNPs showed a variety of different allele frequency change patterns across generations, indicative of an underlying polygenic basis. We did not detect strong linkage around candidate SNPs, but rather a small but long-ranging effect. In conclusion, we found that history played a major role in genomic variation and evolution, with initially differentiated populations reaching the same adaptive outcome through different genetic routes.publishersversionpublishe

Low Serum Levels of DKK2 Predict Incident Low-Impact Fracture in Older Women

There are currently no robust noninvasive markers of fragility fractures. Secreted frizzled related protein-1 (sFRP-1), dickkopf-related protein 1 (DKK1) and DKK2, and sclerostin (SOST) inhibit Wnt signaling and interfere with osteoblast-mediated bone formation. We evaluated associations of serum levels of sFRP-1, DKK1, DKK2, and SOST with incident low-impact fracture and BMD in 828 women aged ≥65 years from EpiDoC, a longitudinal population-based cohort. A structured questionnaire during a baseline clinical appointment assessed prevalent fragility fractures and clinical risk factors (CRFs) for fracture. Blood was collected to measure serum levels of bone turnover markers and Wnt regulators. Lumbar spine and hip BMD were determined by DXA scanning. Follow-up assessment was performed through a phone interview; incident fragility fracture was defined by any new self-reported low-impact fracture. Multivariate Cox proportional hazard models were used to analyze fracture risk adjusted for CRFs and BMD. During a mean follow-up of 2.3 ± 1.0 years, 62 low-impact fractures were sustained in 58 women. A low serum DKK2 level (per 1 SD decrease) was associated with a 1.5-fold increase in fracture risk independently of BMD and CRFs. Women in the two lowest DKK2 quartiles had a fracture incidence rate of 32 per 1000 person-years, whereas women in the two highest quartiles had 14 fragility fractures per 1000 person-years. A high serum sFRP1 level was associated with a 1.6-fold increase in fracture risk adjusted for CRFs, but not independently of BMD. Serum levels of SOST (r = 0.191; p = 0.0025) and DKK1(r = -0.1725; p = 0.011) were correlated with hip BMD, but not with incident fragility fracture. These results indicate that serum DKK2 and sFRP1 may predict low-impact fracture. The low number of incident fractures recorded is a limitation and serum levels of Wnt regulators should be further studied in other populations as potential noninvasive markers of fragility fractures. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.publishersversionpublishe

MARC1 p.A165T variant is associated with decreased markers of liver injury and enhanced antioxidant capacity in autoimmune hepatitis

The clinical picture of autoimmune hepatitis (AIH) varies markedly between patients, potentially due to genetic modifiers. The aim of this study was to evaluate genetic variants previously associated with fatty liver as potential modulators of the AIH phenotype. The study cohort comprised 313 non-transplanted adults with AIH. In all patients, the MARC1 (rs2642438), HSD17B13 (rs72613567), PNPLA3 (rs738409), TM6SF2 (rs58542926), and MBOAT7 (rs641738) variants were genotyped using TaqMan assays. Mitochondrial damage markers in serum were analyzed in relation to the MARC1 variant. Carriers of the protective MARC1 allele had lower ALT and AST (both P < 0.05). In patients treated for AIH for ≥ 6 months, MARC1 correlated with reduced AST, ALP, GGT (all P ≤ 0.01), and lower APRI (P = 0.02). Patients carrying the protective MARC1 genotype had higher total antioxidant activity (P < 0.01) and catalase levels (P = 0.02) in serum. The PNPLA3 risk variant was associated with higher MELD (P = 0.02) in treated patients, whereas MBOAT7 increased the odds for liver cancer (OR = 3.71). None of the variants modulated the risk of death or transplantation. In conclusion, the MARC1 polymorphism has protective effects in AIH. Genotyping of MARC1, PNPLA3, and MBOAT7 polymorphisms might help to stratify patients with AIH