Differential preservation of endogenous human and microbial DNA in dental calculus and dentin

Dental calculus (calcified dental plaque) is prevalent in archaeological skeletal collections and is a rich source of oral microbiome and host-derived ancient biomolecules. Recently, it has been proposed that dental calculus may provide a more robust environment for DNA preservation than other skeletal remains, but this has not been systematically tested. In this study, shotgun-sequenced data from paired dental calculus and dentin samples from 48 globally distributed individuals are compared using a metagenomic approach. Overall, we find DNA from dental calculus is consistently more abundant and less contaminated than DNA from dentin. The majority of DNA in dental calculus is microbial and originates from the oral microbiome; however, a small but consistent proportion of DNA (mean 0.08 ± 0.08%, range 0.007–0.47%) derives from the host genome. Host DNA content within dentin is variable (mean 13.70 ± 18.62%, range 0.003–70.14%), and for a subset of dentin samples (15.21%), oral bacteria contribute \u3e 20% of total DNA. Human DNA in dental calculus is highly fragmented, and is consistently shorter than both microbial DNA in dental calculus and human DNA in paired dentin samples. Finally, we find that microbial DNA fragmentation patterns are associated with guanine-cytosine (GC) content, but not aspects of cellular structure

Identification of a General O-linked Protein Glycosylation System in Acinetobacter baumannii and Its Role in Virulence and Biofilm Formation

Acinetobacter baumannii is an emerging cause of nosocomial infections. The isolation of strains resistant to multiple antibiotics is increasing at alarming rates. Although A. baumannii is considered as one of the more threatening “superbugs” for our healthcare system, little is known about the factors contributing to its pathogenesis. In this work we show that A. baumannii ATCC 17978 possesses an O-glycosylation system responsible for the glycosylation of multiple proteins. 2D-DIGE and mass spectrometry methods identified seven A. baumannii glycoproteins, of yet unknown function. The glycan structure was determined using a combination of MS and NMR techniques and consists of a branched pentasaccharide containing N-acetylgalactosamine, glucose, galactose, N-acetylglucosamine, and a derivative of glucuronic acid. A glycosylation deficient strain was generated by homologous recombination. This strain did not show any growth defects, but exhibited a severely diminished capacity to generate biofilms. Disruption of the glycosylation machinery also resulted in reduced virulence in two infection models, the amoebae Dictyostelium discoideum and the larvae of the insect Galleria mellonella, and reduced in vivo fitness in a mouse model of peritoneal sepsis. Despite A. baumannii genome plasticity, the O-glycosylation machinery appears to be present in all clinical isolates tested as well as in all of the genomes sequenced. This suggests the existence of a strong evolutionary pressure to retain this system. These results together indicate that O-glycosylation in A. baumannii is required for full virulence and therefore represents a novel target for the development of new antibiotics

The Regulatory Network of Natural Competence and Transformation of Vibrio cholerae

The human pathogen Vibrio cholerae is an aquatic bacterium frequently encountered in rivers, lakes, estuaries, and coastal regions. Within these environmental reservoirs, the bacterium is often found associated with zooplankton and more specifically with their chitinous exoskeleton. Upon growth on such chitinous surfaces, V. cholerae initiates a developmental program termed “natural competence for genetic transformation.” Natural competence for transformation is a mode of horizontal gene transfer in bacteria and contributes to the maintenance and evolution of bacterial genomes. In this study, we investigated competence gene expression within this organism at the single cell level. We provide evidence that under homogeneous inducing conditions the majority of the cells express competence genes. A more heterogeneous expression pattern was observable on chitin surfaces. We hypothesize that this was the case due to the heterogeneity around the chitin surface, which might vary extensively with respect to chitin degradation products and autoinducers; these molecules contribute to competence induction based on carbon catabolite repression and quorum-sensing pathways, respectively. Therefore, we investigated the contribution of these two signaling pathways to natural competence in detail using natural transformation assays, transcriptional reporter fusions, quantitative RT–PCR, and immunological detection of protein levels using Western blot analysis. The results illustrate that all tested competence genes are dependent on the transformation regulator TfoX. Furthermore, intracellular cAMP levels play a major role in natural transformation. Finally, we demonstrate that only a minority of genes involved in natural transformation are regulated in a quorum-sensing-dependent manner and that these genes determine the fate of the surrounding DNA. We conclude with a model of the regulatory circuit of chitin-induced natural competence in V. cholerae

2020 Proceedings of the 3rd International Conference on Trauma Surgery Technology in Giessen

The 3 rd event of the Giessen International Conference on Trauma Surgery Technology on October, the 17th 2020 was hosted on Zoom in accordance with the worldwide corona situation. Dr Mieczakowski, Dr Yu, and Wolfram drafted in 2018 from Jan’s apartment in Bremen the manuscript which was submitted to and approved for funding by the Deutsche Forschungsgemeinschaft (DFG). At that time, we had no idea what substantial changes the conferencing concept would require. This is why we would like to thank again Michele. She first planned this year’s event after the 2019 date and then in the spring of 2020 had to replan for the new situation

Use of a Water Filter at Home Reduces Sugary Drink Consumption among Parents and Toddlers in Predominantly Hispanic Community: Results From the Water Up!@ Home Intervention Trial

BACKGROUND: Water is recommended as an alternative for sugar-sweetened beverages (SSB). Low-income, minority groups in the US continue to exhibit high SSB and low water consumption, and are more likely to exceed 100% fruit juice recommendation. OBJECTIVE: To test the effects of a home-based intervention designed to replace SSB with tap water and reduce excess juice consumption among parents and their infants/toddlers. DESIGN: Randomized Controlled Trial PARTICIPANTS: Parents (n=92) of infants/toddlers who participated in 3 Early Head Start (EHS) home-visiting programs that serve predominantly Hispanic, low-income communities 2019-2021. INTERVENTION: The 12-week intervention (Water Up!@Home) simultaneously addressed: a) physical barriers to tap water consumption (via a water filter); b) sociocultural barriers to replacing SSB and juice with water (via a curriculum). Comparison group received a water filter only. HYPOTHESIS: Intervention will lead to a reduction of 6 fl oz /day in SSB and juice consumption. MAIN OUTCOMES: Parent-reported self and infant/toddler SSB; water (filtered, tap, bottled); 100% fruit juice consumption. STATISTICAL ANALYSES: ANCOVA to compare changes in consumption between experimental groups; t-tests to assess changes within groups. RESULTS: Participants in both groups reported significant reductions in SSB from baseline (parents: intervention [-11.2 fl oz/day, p\u3c0.01]; comparison [-8.0 fl oz/day, p\u3c0.01]; children: intervention [-1.50 fl oz/day, p=0.03]; comparison [-1.56 fl oz/day, p=0.02]), increased water consumption (parents in both groups [+5.6 fl oz/day]; children: intervention [+3.61 fl oz/day, p=0.01], comparison [+2.24 fl oz/day, p=0.05]), mostly from filtered tap water. Differences between groups were not statistically significant. Intervention participants reported significant reductions in 100% fruit juice vs. comparison (parents: -3.6 fl oz/day vs. -1.0 fl oz/day, p\u3c0.01; children: -0.73 fl oz/day vs. +0.48 fl oz/day, p=0.03). CONCLUSIONS: The intervention effectively reduced 100% fruit juice consumption. Water security should be examined as a contributor to SSB consumption in this population

Disulfide Bond Formation and ToxR Activity in <em>Vibrio cholerae</em>

<div><p>Virulence factor production in <em>Vibrio cholerae</em> is complex, with ToxRS being an important part of the regulatory cascade. Additionally, ToxR is the transcriptional regulator for the genes encoding the major outer membrane porins OmpU and OmpT. ToxR is a transmembrane protein and contains two cysteine residues in the periplasmic domain. This study addresses the influence of the thiol-disulfide oxidoreductase system DsbAB, ToxR cysteine residues and ToxR/ToxS interaction on ToxR activity. The results show that porin production correlates with ToxR intrachain disulfide bond formation, which depends on DsbAB. In contrast, formation of ToxR intrachain or interchain disulfide bonds is dispensable for virulence factor production and in vivo colonization. This study further reveals that in the absence of ToxS, ToxR interchain disulfide bond formation is facilitated, whereat cysteinyl dependent homo- and oligomerization of ToxR is suppressed if ToxS is coexpressed. In summary, new insights into gene regulation by ToxR are presented, demonstrating a mechanism by which ToxR activity is linked to a DsbAB dependent intrachain disulfide bond formation.</p> </div

<i>dsbA</i> knockout mutant and ToxR forms.

<p>Immunoblot analyses are shown using anti-FLAG antibodies to detect FLAG-tagged ToxR produced in <i>V. cholerae</i> P27459-S Δ<i>toxRS</i> and Δ<i>toxRS</i> Δ<i>dsbA</i> mutant strain (as indicated in the figure). Bacterial cultures harboring pFLAGtoxRS were grown to mid-log phase in M9 glycerol and in LB broth and induced with IPTG. ToxR mobility in the different samples was monitored and differences for intrachain disulfide bond formation were detected. Immunoblot analysis was performed at least three times, and results were reproducible.</p

Bacteria strains and plasmids used in this study.

<p>Bacteria strains and plasmids used in this study.</p