Does virulence assessment of Vibrio anguillarum using sea bass (Dicentrarchus labrax) larvae correspond with genotypic and phenotypic characterization?

Background: Vibriosis is one of the most ubiquitous fish diseases caused by bacteria belonging to the genus Vibrio such as Vibrio (Listonella) anguillarum. Despite a lot of research efforts, the virulence factors and mechanism of V. anguillarum are still insufficiently known, in part because of the lack of standardized virulence assays. Methodology/Principal Findings: We investigated and compared the virulence of 15 V. anguillarum strains obtained from different hosts or non-host niches using a standardized gnotobiotic bioassay with European sea bass (Dicentrarchus labrax L.) larvae as model hosts. In addition, to assess potential relationships between virulence and genotypic and phenotypic characteristics, the strains were characterized by random amplified polymorphic DNA (RAPD) and repetitive extragenic palindromic PCR (rep-PCR) analyses, as well as by phenotypic analyses using Biolog's Phenotype MicroArray (TM) technology and some virulence factor assays. Conclusions/Significance: Virulence testing revealed ten virulent and five avirulent strains. While some relation could be established between serotype, genotype and phenotype, no relation was found between virulence and genotypic or phenotypic characteristics, illustrating the complexity of V. anguillarum virulence. Moreover, the standardized gnotobiotic system used in this study has proven its strength as a model to assess and compare the virulence of different V. anguillarum strains in vivo. In this way, the bioassay contributes to the study of mechanisms underlying virulence in V. anguillarum

Assessing the potential of wild yeasts for bioethanol production

Bioethanol fermentations expose yeasts to a new, complex and challenging fermentation medium with specific inhibitors and sugar mixtures depending on the type of carbon source. It is, therefore, suggested that the natural diversity of yeasts should be further exploited in order to find yeasts with good ethanol yield in stressed fermentation media. In this study, we screened more than 50 yeast isolates of which we selected five isolates with promising features. The species Candida bombi, Wickerhamomyces anomalus and Torulaspora delbrueckii showed better osmo- and hydroxymethylfurfural tolerance than Saccharomyces cerevisiae. However, S. cerevisiae isolates had the highest ethanol yield in fermentation experiments mimicking high gravity fermentations (25\ua0% glucose) and artificial lignocellulose hydrolysates (with a myriad of inhibitors). Interestingly, among two tested S. cerevisiaestrains, a wild strain isolated from an oak tree performed better than Ethanol Red, a S. cerevisiae strain which is currently commonly used in industrial bioethanol fermentations. Additionally, a W. anomalus strain isolated from sugar beet thick juice was found to have a comparable ethanol yield, but needed longer fermentation time. Other non-Saccharomycesyeasts yielded lower ethanol amounts

Phenotypic evaluation of natural and industrial Saccharomyces yeasts for different traits desirable in industrial bioethanol production

Saccharomyces cerevisiae is the organism of choice for many food and beverage fermentations because it thrives in high-sugar and high-ethanol conditions. However, the conditions encountered in bioethanol fermentation pose specific challenges, including extremely high sugar and ethanol concentrations, high temperature, and the presence of specific toxic compounds. It is generally considered that exploring the natural biodiversity of Saccharomyces strains may be an interesting route to find superior bioethanol strains and may also improve our understanding of the challenges faced by yeast cells during bioethanol fermentation. In this study, we phenotypically evaluated a large collection of diverse Saccharomyces strains on six selective traits relevant for bioethanol production with increasing stress intensity. Our results demonstrate a remarkably large phenotypic diversity among different Saccharomyces species and among S. cerevisiae strains from different origins. Currently applied bioethanol strains showed a high tolerance to many of these relevant traits, but several other natural and industrial S. cerevisiae strains outcompeted the bioethanol strains for specific traits. These multitolerant strains performed well in fermentation experiments mimicking industrial bioethanol production. Together, our results illustrate the potential of phenotyping the natural biodiversity of yeasts to find superior industrial strains that may be used in bioethanol production or can be used as a basis for further strain improvement through genetic engineering, experimental evolution, or breeding. Additionally, our study provides a basis for new insights into the relationships between tolerance to different stressors

Laophontopsis Sars and the taxonomic concept of the Normanellinae (Copepoda: Harpacticoida): A revision

The taxonomie concept of the subfamily Normanellinae Lang (Harpacticoida, Laophontidae) is revised. As a result a new family Laophontopsidae is proposed to accommodate Laophontopsis Sars and two new genera Aculeopsis and Telodocus. It is concluded that the presumed boreo-mediterranean distribution pattern displayed by the type species L. lamellifera (Claus) is merely the result of erroneous identifications. The population of northwest Europe is assigned to a new species L. borealis and another new species L. monardi is proposed for Monard’s (1928) material from Banyuls-sur-Mer. L. secundus Sewell is placed in the new genus Telodocus. Aculeopsis gen. nov. embraces only A. longisetosa spec. nov. and constitutes the most primitive genus of the family. The Laophontopsidae are placed within the superfamily Laophontoidea. The Normanellinae are provisionally upgraded to family level despite their diphyletic status because this narrows the diagnosis of the Laophontidae considerably. The genera are attributed to two clearly defined but non-related subfamilies, Normanellinae Lang (Normanella Brady) and Cletopsyllinae subfam. nov. (Cletopsyllus Willey, Pseudocletopsyllus Vervoort). The genus Pseudocleta Lang is relegated to incertae sedis within the Laophontoidae

Protective effect of hop β-acids on microbial degradation of thick juice during storage

Storing sugar extracts as thick juice, a form of sucrose syrup, is common practice in the sugar industry. However, thick juice storage commonly faces problems due to microbial degradation. In this study the value of a commercial alkaline solution of hop β-acids (HBA) was assessed for prevention of microbial degradation of thick juice. The antimicrobial effect of different concentrations of HBA against juice degradation was tested in a pilot-scale thick juice storage experiment. Thick juice degradation, indicated as a decrease in pH, was generally accompanied by an increase in the count of fastidious bacteria (FB) on Columbia Agar with Sheep Blood (CAwSB), which were mainly identified as Tetragenococcus halophilus. Addition of HBA delayed juice acidification and the development of T. halophilus in a concentration-dependent manner. The susceptibility of T. halophilus to HBA was determined by plating degraded thick juice (> 105 CFU/ml) on CAwSB plates with different concentrations of HBA (0–160 ppm). None of the HBA concentrations tested reduced the number of FB colonies formed, but increasing HBA concentrations extended the lag time of colony formation. In conclusion, HBA can prolong the storage life of thick juice in the sugar industry, although degradation cannot be eliminated.status: publishe

Retracted COVID-19 Papers and the level of 'citation pollution': a preliminary analysis and directions for future research

Retraction Watch maintains a "running list" of retracted papers on Covid-19 related research. By the end of September 2020, thirty-three retracted Covid-19 papers were listed. We analysed these retracted papers, focusing specifically on how they have been cited by review papers, and subsequently how they have penetrated and potentially distorted public discourse and legitimate research on Covid-19. The study demonstrates the need for more in-depth studies that focus on the phenomenon of citation pollution. We show that the "Covid-19 publication race", amplified by a pressure-to-publish research culture, distorted published science on Covid-19. We highlight the urgency to engage popular media and critical decision makers on how to distinguish between questionable and legitimate science. We also emphasise the importance of dealing with illegitimate research in a timely manner, both from a scholarly communications and research quality perspective.Retraction Watch maintient une "liste courante" des articles rétractés sur les recherches liées au Covid-19. Fin septembre 2020, trente-trois articles rétractés sur le Covid-19 étaient répertoriés. Nous avons analysé ces articles rétractés, en nous concentrant spécifiquement sur la façon dont ils ont été cités par d'autres articles, et ensuite sur la façon dont ils ont pénétré et potentiellement faussé le discours public et la recherche légitime sur le Covid-19. L'étude démontre le besoin d'études plus approfondies qui se concentrent sur le phénomène de la pollution des citations. Nous montrons que la "course à la publication sur le Covid-19", amplifiée par une culture de la pression à la publication de la recherche, a déformé l'information scientifique publiée sur le Covid-19. Nous soulignons l'urgence d'engager les médias populaires et les décideurs critiques sur la manière de distinguer la science douteuse de la science légitime. Nous soulignons également l'importance de traiter rapidement les recherches illégitimes, tant du point de vue de la communication scientifique que de la qualité de la recherche.Retraction Watch houdt een "lopende lijst" bij van ingetrokken papieren over Covid-19-gerelateerd onderzoek. Eind september 2020 waren drieëndertig ingetrokken Covid-19 papieren op de lijst geplaatst. We hebben deze ingetrokken papieren geanalyseerd, waarbij we ons specifiek hebben gericht op de manier waarop ze zijn geciteerd door review papers, en vervolgens op de manier waarop ze zijn doorgedrongen en mogelijk vervormd in het publieke discours en het legitieme onderzoek naar Covid-19. De studie toont aan dat er behoefte is aan meer diepgaande studies die zich richten op het fenomeen van de citatievervuiling. We tonen aan dat de "Covid-19-publicatierace", versterkt door een druk om te publiceren onderzoekscultuur, de gepubliceerde wetenschap over Covid-19 vertekend heeft. We benadrukken de urgentie om de populaire media en kritische besluitvormers te betrekken bij het maken van een onderscheid tussen twijfelachtige en legitieme wetenschap. We benadrukken ook het belang van het tijdig aanpakken van onrechtmatig onderzoek, zowel vanuit het oogpunt van wetenschappelijke communicatie als vanuit het oogpunt van de kwaliteit van het onderzoek

IFN-beta interferes with the differentiation of dendritic cells from peripheral blood mononuclear cells: selective inhibition of CD40-dependent interleukin-12 secretion.

We studied the effects of interferon-beta (IFN-beta) on the differentiation of dendritic cells (DC) obtained by culturing plastic-adherent peripheral blood mononuclear cells (PBMC) from a total of 30 healthy volunteers in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). First, we found that the addition of IFN-beta at the initiation of the culture did not modify DC morphology but caused a reproducible and statistically significant upregulation of HLA-DR, CD86, and CD80 surface expression. CD1a expression was significantly reduced, and CD40 expression was unchanged. We then determined the influence of IFN-beta on the production of cytokines by DC. DC differentiated in the presence of IFN-beta secreted significantly less IL-12 (p40 and p70) both spontaneously and on activation by fibroblasts transfected with the CD40L gene. This effect of IFN-beta was dose dependent and selective, as it was not observed for IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha). As a consequence, DC differentiated in the presence of IFN-beta induced significantly less IFN-gamma secretion by alloreactive T cells, whereas they were more efficient than control DC in eliciting IL-5 secretion. We conclude that the direct action of IFN-beta on DC causes inhibition of their ability to secrete IL-12 in response to CD40 ligation and to elicit Th1 type responses.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Characterization of the bacterial community composition in water of drinking water production and distribution systems in Flanders, Belgium

The quality of drinking water is influenced by its chemical and microbial composition which in turn may be affected by the source water and the different processes applied in drinking water purification systems. In this study, we investigated the bacterial diversity in different water samples from the production and distribution chain of thirteen drinking water production and distribution systems from Flanders (Belgium) that use surface water or groundwater as source water. Water samples were collected over two seasons from the source water, the processed drinking water within the production facility and out of the tap in houses along its distribution network. 454-pyrosequencing of 16S ribosomal RNA gene sequences revealed a total of 1,570 species-level bacterial operational taxonomic units. Strong differences in community composition were found between processed drinking water samples originating from companies that use surface water and other that use groundwater as source water. Proteobacteria was the most abundant phylum in all samples. Yet, several phyla including Actinobacteria were significantly more abundant in surface water while Cyanobacteria were more abundant in surface water and processed water originating from surface water. Gallionella, Acinetobacter, and Pseudomonas were the three most abundant genera detected. Members of the Acinetobacter genus were even found at a relative read abundance of up to 47.5% in processed water samples, indicating a general occurrence of Acinetobacter in drinking water (systems).status: publishe