Genetic manipulation of structural colour in bacterial colonies

Naturally occurring photonic structures are responsible for the bright and vivid coloration in a large variety of living organisms. Despite efforts to understand their biological functions, development and complex optical response, little is known of the underlying genes involved in the development of these nanostructures in any domain of life. Here, we used Flavobacterium colonies as a model system to demonstrate that genes responsible for gliding motility, cell shape, the stringent response and tRNA modification contribute to the optical appearance of the colony. By structural and optical analysis, we obtained a detailed correlation of how genetic modifications alter structural colour in bacterial colonies. Understanding of genotype and phenotype relations in this system opens the way to genetic engineering of on-demand living optical materials, for use as paints and living sensors

Exploring the link between leaky-gut-related markers and metabolic health in a large dutch adult population

A leaky gut can trigger chronic inflammation and poses a primary risk for metabolic diseases. This study established a relationship between intestinal integrity (leaky gut) and metabolic health in a general population. Leaky-gut markers (LGMs) were studied in a large population of Dutch adults with a broad spectrum of metabolic health. This study enrolled 500 individuals selected within the NQplus cohort study (n = 2048) by stratified randomization, based on waist circumference, fasting glucose, and high-density lipoprotein (HDL) cholesterol to obtain a represen-tative and balanced population in terms of metabolic health parameters, sex (male/female), and age (<54/≥54 years). LGMs—zonulin, lipopolysaccharide-binding protein (LBP), and soluble CD14 (sCD14)—were measured in EDTA plasma or serum. Zonulin was most strongly associated with metabolic health. Zonulin and LBP were most strongly associated with the inflammatory marker C-reactive protein (CRP). The quartile analysis for zonulin and LBP showed that most metabolic health parameters and CRP levels increased from Q1 to Q4, with significant differences between quartiles, except for markers related to glucose homeostasis (glucose and glycated hemoglobin A1c (HbA1c)). Associations between LGMs and metabolic health parameters in this large Dutch adult population indicate that LGMs are valuable markers for identifying people at risk of a leaky gut and subsequent chronic inflammation linked to metabolic disorders

Traiter ou ne pas traiter?

La décision de traiter ou non repose sur le risque fracturaired'un patient, son adhésion à la prise en charge, l'efficacité dutraitement et son profil d'effets indésirables, et sur le remboursementde ce dernier. Différents algorithmes, dont l'outil FRAX,permettent d'évaluer le risque fracturaire. Ce dernier outil aquelques limites: absence de quantification du type de fracturesantérieures, mauvaise appréciation du risque lié à une corticothérapiesystémique active, absence de validation prospective.Le seuil thérapeutique peut être fixe indépendant de l'âgeou varier avec l'âge. Les analyses coût-efficacité montrent quepour un même profil de risque, plus la personne est âgée, plusgrand est le bénéfice économique. Le jugement clinique peutnous guider dans certaines situations. La fracture non traumatique,l'âge avancé, la corticothérapie, un T-score abaissé sontles principaux facteurs de risque utilisés en pratique. Dans l'approchediagnostique, la recherche de la fracture vertébrale sousjacenteest impérative, idéalement par IVA. Les quelques exemplesci-dessous montrent les limites des algorithmes et dujugement clinique.Sans facteur de risque pour l'ostéoporose, mais avec un T-scoreà -3.2 DS, à quel âge va-t-on débuter un traitement chez cettefemme ? Avant ou après 60 ans ? Certaines situations cliniquessemblent claires et posent l'indication à traiter: la fracture de lahanche, la fracture vertébrale spontanée, la corticothérapie aulong cours. Mais si pour ces trois situations la densitométrieosseuse donne un T-score à -0.5 DS, ou si le patient a 35 ans,est-ce que chaque clinicien sera d'accord de traiter ? On saitpar exemple que le risque fracturaire sous corticothérapie aulong cours semble faible chez la femme préménopausée et chezl'homme avant 50 ans. Que faire après une fracture du poignetà 50 ans : ne pas traiter si le T-score est à -1.5 DS et traiter si leT-score est à -3 DS ? L'antécédent de fracture du poignet n'estpas un facteur de risque aussi fort de la fracture subséquenteque la hanche, la vertèbre ou l'humérus. Et chez cette femme de80 ans ayant eu une fracture de côte sur un effort de toux, avecun T-score à -2.5 DS ? Ou cette autre femme de 83 ans, sansfacteur de risque particulier pour l'ostéoporose mais avec unT-score à -3.1 DS ? Ces deux dernières femmes bénéficient d'untraitement en terme économique et le praticien respecte les indicationsau remboursement. Mais certains modèles préconisentde ne pas traiter les personnes très âgées si leur risque fracturairen'est pas très élevé.Dans toutes ces situations, le partage de la décision entre lepraticien et son patient prime sur les éventuelles propositionsissues d'algorithmes qui doivent encore être améliorés

Dark chocolate consumption improves leukocyte adhesion factors and vascular function in overweight men

Flavanol-enriched chocolate consumption increases endothelium-dependent vasodilation. Most research so far has focused on flow-mediated dilation (FMD) only; the effects on other factors relevant to endothelial health, such as inflammation and leukocyte adhesion, have hardly been addressed. We investigated whether consumption of regular dark chocolate also affects other markers of endothelial health, and whether chocolate enrichment with flavanols has additional benefits. In a randomized double-blind crossover study, the effects of acute and of 4 wk daily consumption of high flavanol chocolate (HFC) and normal flavanol chocolate (NFC) on FMD, augmentation index (AIX), leukocyte count, plasma cytokines, and leukocyte cell surface molecules in overweight men (age 45-70 yr) were investigated. Sensory profiles and motivation scores to eat chocolate were also collected. Findings showed that a 4 wk chocolate intake increased FMD by 1%, which was paralleled by a decreased AIX of 1%, decreased leukocyte cell count, decreased plasma sICAM1 and sICAM3, and decreased leukocyte adhesion marker expression (

Lactobacillus acidophilus attenuates Salmonella-induced stress of epithelial cells by modulating tight-junction genes and cytokine responses

Scope: Salmonellosis is a prevalent food-borne illness that causes diarrhea in over 130 million humans yearly and can lead to death. There is an urgent need to find alternatives to antibiotics as many salmonellae are now multidrug resistant. As such, specific beneficial bacteria and dietary fibers can be an alternative as they may prevent Salmonella Typhimurium (STM) infection and spreading by strengthening intestinal barrier function. Methods and Results: We tested whether immune active long-chain inulin-type fructans and/or L. acidophilus W37, L. brevis W63, and L. casei W56 can strengthen barrier integrity of intestinal Caco-2 cells in the presence and absence of a STM. Effects of the ingredients on intestinal barrier function were first evaluated by quantifying trans-epithelial electric resistance (TEER) and regulation of gene expression by microarray. Only L. acidophilus had effects on TEER and modulated a group of 26 genes related to tight-junctions. Inulin-type fructans, L. brevis W63 and L. casei W56 regulated other genes, unrelated to tight-junctions. L. acidophilus also had unique effects on a group of six genes regulating epithelial phenotype toward follicle-associated epithelium. L. acidophilus W37 was therefore selected for a challenge with STM and prevented STM-induced barrier disruption and decreased secretion of IL-8. Conclusion: L. acidophilus W37 increases TEER and can protect against STM induced disruption of gut epithelial cells integrity in vitro. Our results suggest that selection of specific bacterial strains for enforcing barrier function may be a promising strategy to reduce or prevent STM infections.</p

Clostridioides difficile toxin A-mediated Caco-2 cell barrier damage was attenuated by insect-derived fractions and corresponded to increased gene transcription of cell junctional and proliferation proteins

Pathogenesis of C. difficile in the intestine is associated with the secretion of toxins which can damage the intestinal epithelial layer and result in diseases such as diarrhoea. Treatment for C. difficile infections consists of antibiotics which, however, have non-specific microbiocidal effects and may cause intestinal dysbiosis which results in subsequent health issues. Therefore, alternative treatments to C. difficile infections are required. We investigated whether different black soldier fly- and mealworm-derived fractions, after applying the INFOGEST digestion protocol, could counteract C. difficile toxin A-mediated barrier damage of small intestinal Caco-2 cells. Treatment and pre-treatment with insect-derived fractions significantly (p < 0.05) mitigated the decrease of the transepithelial electrical resistance (TEER) of Caco-2 cells induced by C. difficile toxin A. In relation to these effects, RNA sequencing data showed an increased transcription of cell junctional and proliferation protein genes in Caco-2 cells. Furthermore, the transcription of genes regulating immune signalling was also increased. To identify whether this resulted in immune activation we used a Caco-2/THP-1 co-culture model where the cells were only separated by a permeable membrane. However, the insect-derived fractions did not change the basolateral secreted IL-8 levels in this model. To conclude, our findings suggest that black soldier fly- and mealworm-derived fractions can attenuate C. difficile induced intestinal barrier disruption and they might be promising tools to reduce the symptoms of C. difficile infections

Identification of leaky gut-related markers as indicators of metabolic health in Dutch adults: The Nutrition Questionnaires plus (NQplus) study.

Background and aimChronic inflammation is a primary risk factor for chronic metabolic disease and may be triggered by a "leaky gut." Several biomarkers have been recognized to indicate intestinal permeability (i.e., leaky gut) and bacterial translocation. Nonetheless, which of these biomarkers exhibit the highest correlation with metabolic health parameters remains unclear. Hence, this study aimed to explore the correlation between leaky gut-related markers and metabolic health.MethodsBased on waist circumference, plasma fasting glucose, plasma gamma-glutamyl transpeptidase (GGT), and plasma LDL cholesterol, two groups of 40 subjects with the most extreme metabolic health profiles were selected from the NQplus cohort study (n = 2048), which was previously conducted by the Wageningen University's Division of Human Nutrition. Eight potential leaky gut-related markers were selected from the literature and measured in serum or EDTA plasma samples of these selected individuals. These samples were also obtained from the NQplus cohort study.ResultsFrom the leaky gut markers, levels of zonulin, lipopolysaccharide-binding protein, soluble CD14, bactericidal/permeability-increasing protein, and peptidoglycan were significantly higher in individuals with unhealthy metabolic profiles (pConclusionsBiomarkers that link a leaky gut and subsequent bacterial translocation to metabolic health were identified in this study. Especially zonulin may aid in monitoring a leaky gut and detecting individuals at risk for developing chronic metabolic diseases

Research data supporting "Genetic manipulation of structural colour in bacterial colonies"

This data supports the publication "Living colours: Genetic manipulation of structural colour in bacterial colonies" and consists of electron microscopy images, a microscope video and goniometer data