181 research outputs found

    Monodopsis and Vischeria genomes shed new light on the biology of eustigmatophyte algae

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    Acknowledgment This study was supported by the National Science Foundation Dimensions of Biodiversity grant (1831428) to F.-W.L., and the Czech Science Foundation grant 20-27648S to M.E. We thank the reviewers and editor for their thoughtful commentsPeer reviewedPublisher PD

    Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis

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    The gastrointestinal (GI) tract contains much of the body’s serotonin (5-hydroxytryptamine, 5-HT), but mechanisms controlling the metabolism of gut-derived 5-HT remain unclear. Here, we demonstrate that the microbiota plays a critical role in regulating host 5-HT. Indigenous spore-forming bacteria (Sp) from the mouse and human microbiota promote 5-HT biosynthesis from colonic enterochromaffin cells (ECs), which supply 5-HT to the mucosa, lumen, and circulating platelets. Importantly, microbiota-dependent effects on gut 5-HT significantly impact host physiology, modulating GI motility and platelet function. We identify select fecal metabolites that are increased by Sp and that elevate 5-HT in chromaffin cell cultures, suggesting direct metabolic signaling of gut microbes to ECs. Furthermore, elevating luminal concentrations of particular microbial metabolites increases colonic and blood 5-HT in germ-free mice. Altogether, these findings demonstrate that Sp are important modulators of host 5-HT and further highlight a key role for host-microbiota interactions in regulating fundamental 5-HT-related biological processes

    A tale of two lineages: how the strains of the earliest divergent symbiotic Frankia clade spread over the world

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    It is currently assumed that around 100 million years ago, the common ancestor to the Fabales, Fagales, Rosales and Cucurbitales in Gondwana, developed a root nodule symbiosis with a nitrogen-fixing bacterium. The symbiotic trait evolved first in Frankia cluster-2; thus, strains belonging to this cluster are the best extant representatives of this original symbiont. Most cluster-2 strains could not be cultured to date, except for Frankia coriariae, and therefore many aspects of the symbiosis are still elusive. Based on phylogenetics of cluster-2 metagenome-assembled genomes (MAGs), it has been shown that the genomes of strains originating in Eurasia are highly conserved. These MAGs are more closely related to Frankia cluster-2 in North America than to the single genome available thus far from the southern hemisphere, i.e., from Papua New Guinea. To unravel more biodiversity within Frankia cluster-2 and predict routes of dispersal from Gondwana, we sequenced and analysed the MAGs of Frankia cluster-2 from Coriaria japonica and Coriaria intermedia growing in Japan, Taiwan and the Philippines. Phylogenetic analyses indicate there is a clear split within Frankia cluster-2, separating a continental from an island lineage. Presumably, these lineages already diverged in Gondwana. Based on fossil data on the host plants, we propose that these two lineages dispersed via at least two routes. While the continental lineage reached Eurasia together with their host plants via the Indian subcontinent, the island lineage spread towards Japan with an unknown host plant

    Hand, Foot, and Mouth Disease in China: critical community size and spatial vaccination strategies

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    Hand Foot and Mouth Disease (HFMD) constitutes a considerable burden for health care systems across China. Yet this burden displays important geographic heterogeneity that directly affects the local persistence and the dynamics of the disease, and thus the ability to control it through vaccination campaigns. Here, we use detailed geographic surveillance data and epidemic models to estimate the critical community size (CCS) of HFMD associated enterovirus serotypes CV-A16 and EV-A71 and we explore what spatial vaccination strategies may best reduce the burden of HFMD. We found CCS ranging from 336,979 (±225,866) to 722,372 (±150,562) with the lowest estimates associated with EV-A71 in the southern region of China where multiple transmission seasons have previously been identified. Our results suggest the existence of a regional immigration-recolonization dynamic driven by urban centers. If EV-A71 vaccines doses are limited, these would be optimally deployed in highly populated urban centers and in high-prevalence areas. If HFMD vaccines are included in China's National Immunization Program in order to achieve high coverage rates (>85%), routine vaccination of newborns largely outperforms strategies in which the equivalent number of doses is equally divided between routine vaccination of newborns and pulse vaccination of the community at large

    Recurrent short sleep, chronic insomnia symptoms and salivary cortisol: A 10-year follow-up in the Whitehall II study

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    Although an association between both sleep duration and disturbance with salivary cortisol has been suggested, little is known about the long term effects of poor quality sleep on diurnal cortisol rhythm. The aim of this study was to examine the association of poor quality sleep, categorised as recurrent short sleep duration and chronic insomnia symptoms, with the diurnal release of cortisol. We examined this in 3314 participants from an occupational cohort, originally recruited in 1985-1989. Salivary cortisol was measured in 2007-2009 and six saliva samples were collected: (1) waking, (2) waking + 0.5 h, (3) +2.5 h, (4) +8 h, (5) +12 h and (6) bedtime, for assessment of the cortisol awakening response and the diurnal slope in cortisol secretion. Participants with the first saliva sample collected within 15 min of waking and not on steroid medication were examined. Short sleep duration (≤5 h) and insomnia symptoms (Jenkins scale, highest quartile) were measured in 1997-1999, 2003-2004 and 2007-2009. Recurrent short sleep was associated with a flatter diurnal cortisol pattern. A steeper morning rise in cortisol was observed among those reporting chronic insomnia symptoms at three time points and among those reporting short sleep twice, compared to those who never reported sleep problems. Participants reporting short sleep on three occasions had higher levels of cortisol later in the day, compared to those never reporting short sleep, indicated by a positive interaction with hours since waking (β = 0.02 (95% CI: 0.01, 0.03)). We conclude that recurrent sleep problems are associated with adverse salivary cortisol patterns throughout the day

    Successful Small Intestine Colonization of Adult Mice by Vibrio cholerae Requires Ketamine Anesthesia and Accessory Toxins

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    Vibrio cholerae colonizes the small intestine of adult C57BL/6 mice. In this study, the physical and genetic parameters that facilitate this colonization were investigated. Successful colonization was found to depend upon anesthesia with ketamine-xylazine and neutralization of stomach acid with sodium bicarbonate, but not streptomycin treatment. A variety of common mouse strains were colonized by O1, O139, and non-O1/non-O139 strains. All combinations of mutants in the genes for hemolysin, the multifunctional, autoprocessing RTX toxin (MARTX), and hemagglutinin/protease were assessed, and it was found that hemolysin and MARTX are each sufficient for colonization after a low dose infection. Overall, this study suggests that, after intragastric inoculation, V. cholerae encounters barriers to infection including an acidic environment and an immediate immune response that is circumvented by sodium bicarbonate and the anti-inflammatory effects of ketamine-xylazine. After initial adherence in the small intestine, the bacteria are subjected to additional clearance mechanisms that are evaded by the independent toxic action of hemolysin or MARTX. Once colonization is established, it is suggested that, in humans, these now persisting bacteria initiate synthesis of the major virulence factors to cause cholera disease. This adult mouse model of intestinal V. cholerae infection, now well-characterized and fully optimized, should serve as a valuable tool for studies of pathogenesis and testing vaccine efficacy

    The ITA Space Center and Its Role in Space Education in Brazil

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    This paper presents the ITA Space Center and its mission in the formation of human resources and in the research and development of space products. In 2012 the first aerospace engineers were graduated at ITA, and since then many efforts have been done to improve the engineering education. The first effort was the development of AESP-14 CubeSat project, then the development and launch of ITASAT, a 6U CubeSat. These two projects showed that small satellites projects provide a good learning approach once students were deeply involved in the development process. These two projects opened the opportunity for the creation of the ITA Space Center (CEI -acronym for Centro Espacial ITA in Portuguese). Inside its facilities the ITA Space Center provides capabilities for the development of small space projects such as electronics, software engineering, mechanical design, and simulation with the aid of systems engineering and project management. By means of the graduate and undergraduate programs the ITA Space Center is providing education and integration with the industries and other partner organizations. In developing and delivering space products, and fostering higher education in space, the ITA Space Center is accomplishing of its proposed mission
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