Abstract
The study of bacterial isolates or communities requires the analysis of the therein included plasmids in order to provide an extensive characterization of the organisms. Plasmids harboring ...resistance and virulence factors are of especial interest as they contribute to the dissemination of antibiotic resistance. As the number of newly sequenced bacterial genomes is growing a comprehensive resource is required which will allow to browse and filter the available plasmids, and to perform sequence analyses. Here, we present PLSDB, a resource containing 13 789 plasmid records collected from the NCBI nucleotide database. The web server provides an interactive view of all obtained plasmids with additional meta information such as sequence characteristics, sample-related information and taxonomy. Moreover, nucleotide sequence data can be uploaded to search for short nucleotide sequences (e.g. specific genes) in the plasmids, to compare a given plasmid to the records in the collection or to determine whether a sample contains one or multiple of the known plasmids (containment analysis). The resource is freely accessible under https://ccb-microbe.cs.uni-saarland.de/plsdb/.
Wastewater treatment plants have been identified as important hubs for small particulate plastic, down to the nanometer scale, from urban areas to the environment. The reuse of sludge as fertilizer ...in agricultural practices can lead to accumulation of plastic in the soil. In this study, nanoplastic particles and microplastic fibers were synthesized with a passive inorganic tracer to aid in faster and more quantitative analysis using inductively coupled plasma mass spectrometry (ICP-MS). Using the anaerobic digestate of a pilot wastewater treatment plant spiked with metal-doped plastic, the excess sludge was dewatered, ensuring realistic associations between sludge and plastic. The resulting sludge cake was affixed atop an unsaturated porous-medium column of glass beads to assess: (i) the release of particulate plastic from the sludge, and (ii) the accumulation and mobility of plastic and organic matter through the column (analogous to a soil). A total of three particulate plastic treatments were assessed, in triplicate, where the plastic and mobile organic fractions were monitored for 14 pore water volumes. Due to size-limited transport, low deattachment from the sludge and reduced mobility through the column were found for microplastic fibers (>95% retention). However, cotransport between the mobile organic fraction and nanoplastic particles was observed, with 50% of both retained in the column. These results contribute to the understanding of the fate of particulate plastics and to assessing the associated environmental risks of particle mobility and percolation, particularly for nanoplastics.
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IJS, KILJ, NUK, PNG, UL, UM
Animals sense the environment through pathways that link sensory organs to the brain. In the visual system, these feedforward pathways define the classical feedforward receptive field (ffRF), the ...area in space in which visual stimuli excite a neuron
. The visual system also uses visual context-the visual scene surrounding a stimulus-to predict the content of the stimulus
, and accordingly, neurons have been identified that are excited by stimuli outside their ffRF
. However, the mechanisms that generate excitation to stimuli outside the ffRF are unclear. Here we show that feedback projections onto excitatory neurons in the mouse primary visual cortex generate a second receptive field that is driven by stimuli outside the ffRF. The stimulation of this feedback receptive field (fbRF) elicits responses that are slower and are delayed in comparison with those resulting from the stimulation of the ffRF. These responses are preferentially reduced by anaesthesia and by silencing higher visual areas. Feedback inputs from higher visual areas have scattered receptive fields relative to their putative targets in the primary visual cortex, which enables the generation of the fbRF. Neurons with fbRFs are located in cortical layers that receive strong feedback projections and are absent in the main input layer, which is consistent with a laminar processing hierarchy. The observation that large, uniform stimuli-which cover both the fbRF and the ffRF-suppress these responses indicates that the fbRF and the ffRF are mutually antagonistic. Whereas somatostatin-expressing inhibitory neurons are driven by these large stimuli, inhibitory neurons that express parvalbumin and vasoactive intestinal peptide have mutually antagonistic fbRF and ffRF, similar to excitatory neurons. Feedback projections may therefore enable neurons to use context to estimate information that is missing from the ffRF and to report differences in stimulus features across visual space, regardless of whether excitation occurs inside or outside the ffRF. By complementing the ffRF, the fbRF that we identify here could contribute to predictive processing.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Hidden in plain sight Keller, Andreas J
Science (American Association for the Advancement of Science),
2021-Oct-29, 2021-10-29, 20211029, Volume:
374, Issue:
6567
Journal Article
► Novel handwritten word spotting system using character HMMs. ► Efficient lexicon-free approach. ► Template-free spotting of arbitrary keywords. ► Segmentation-free approach is applied to complete ...text lines. ► Clearly outperforms DTW-based reference system on several data sets.
For retrieving keywords from scanned handwritten documents, we present a word spotting system that is based on character Hidden Markov Models. In an efficient lexicon-free approach, arbitrary keywords can be spotted without pre-segmenting text lines into words. For a multi-writer scenario on the IAM off-line database as well as for two single writer scenarios on historical data sets, it is shown that the proposed learning-based system outperforms a standard template matching method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Significant effort has been devoted to discovering microRNA (miRNA) disease biomarkers. In particular, miRNAs in whole blood or specific blood components are candidates for improving the diagnosis of ...diseases, including life-threatening pathologies. This review covers the challenges crucial for the translation of miRNAs in body fluids (circulating miRNAs) from a research setting into a clinical care scenario. First, we discuss the specificity of miRNA biomarkers for the diagnosis of a disease. While single miRNAs such as miR-20a, miR-21, miR-155, and miR-126 are frequently not disease specific, miRNA signatures that consist of a plurality of different miRNAs may help to improve differentiation between pathologies. Second, we discuss the degree of reproducibility and highlight selected validation studies. While single miRNA markers are often confirmed by independent studies, miRNA signatures are less frequently verified. Third, we address challenges to the profiling of miRNAs in high-throughput settings and we discuss the appropriateness of various analytical platforms and bioinformatics towards a clinical application of miRNAs. Finally, we shed light on the suitability of enriched miRNA sources, e.g. fractionation of body fluids for extracellular vesicles such as exosomes or blood cells, to develop miRNA signatures. With an increasing number of verified miRNA signatures and with the advance of matured medium-throughput approaches in clinical settings, specific miRNA markers are increasingly likely to contribute to human healthcare.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Understanding the relationship between a stimulus and how it is perceived reveals fundamental principles about the mechanisms of sensory perception. While this stimulus-percept problem is mostly ...understood for color vision and tone perception, it is not currently possible to predict how a given molecule smells. While there has been some progress in predicting the pleasantness and intensity of an odorant, perceptual data for a larger number of diverse molecules are needed to improve current predictions. Towards this goal, we tested the olfactory perception of 480 structurally and perceptually diverse molecules at two concentrations using a panel of 55 healthy human subjects.
For each stimulus, we collected data on perceived intensity, pleasantness, and familiarity. In addition, subjects were asked to apply 20 semantic odor quality descriptors to these stimuli, and were offered the option to describe the smell in their own words. Using this dataset, we replicated several previous correlations between molecular features of the stimulus and olfactory perception. The number of sulfur atoms in a molecule was correlated with the odor quality descriptors "garlic," "fish," and "decayed," and large and structurally complex molecules were perceived to be more pleasant. We discovered a number of correlations in intensity perception between molecules. We show that familiarity had a strong effect on the ability of subjects to describe a smell. Many subjects used commercial products to describe familiar odorants, highlighting the role of prior experience in verbal reports of olfactory perception. Nonspecific descriptors like "chemical" were applied frequently to unfamiliar odorants, and unfamiliar odorants were generally rated as neither pleasant nor unpleasant.
We present a very large psychophysical dataset and use this to correlate molecular features of a stimulus to olfactory percept. Our work reveals robust correlations between molecular features and perceptual qualities, and highlights the dominant role of familiarity and experience in assigning verbal descriptors to odorants.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
While the number of human miRNA candidates continuously increases, only a few of them are completely characterized and experimentally validated. Toward determining the total number of true ...miRNAs, we employed a combined in silico high- and experimental low-throughput validation strategy. We collected 28 866 human small RNA sequencing data sets containing 363.7 billion sequencing reads and excluded falsely annotated and low quality data. Our high-throughput analysis identified 65% of 24 127 mature miRNA candidates as likely false-positives. Using northern blotting, we experimentally validated miRBase entries and novel miRNA candidates. By exogenous overexpression of 108 precursors that encode 205 mature miRNAs, we confirmed 68.5% of the miRBase entries with the confirmation rate going up to 94.4% for the high-confidence entries and 18.3% of the novel miRNA candidates. Analyzing endogenous miRNAs, we verified the expression of 8 miRNAs in 12 different human cell lines. In total, we extrapolated 2300 true human mature miRNAs, 1115 of which are currently annotated in miRBase V22. The experimentally validated miRNAs will contribute to revising targetomes hypothesized by utilizing falsely annotated miRNAs.
Context guides perception by influencing stimulus saliency. Accordingly, in visual cortex, responses to a stimulus are modulated by context, the visual scene surrounding the stimulus. Responses are ...suppressed when stimulus and surround are similar but not when they differ. The underlying mechanisms remain unclear. Here, we use optical recordings, manipulations, and computational modeling to show that disinhibitory circuits consisting of vasoactive intestinal peptide (VIP)-expressing and somatostatin (SOM)-expressing inhibitory neurons modulate responses in mouse visual cortex depending on similarity between stimulus and surround, primarily by modulating recurrent excitation. When stimulus and surround are similar, VIP neurons are inactive, and activity of SOM neurons leads to suppression of excitatory neurons. However, when stimulus and surround differ, VIP neurons are active, inhibiting SOM neurons, which leads to relief of excitatory neurons from suppression. We have identified a canonical cortical disinhibitory circuit that contributes to contextual modulation and may regulate perceptual saliency.
•Visual context modulates the response of SOM oppositely to all other V1 neurons•The VIP-SOM disinhibitory circuit controls the impact of context on V1 responses•The VIP-SOM disinhibitory circuit controls V1 by modulating recurrent excitation•As we predict by modeling, silencing of VIP neurons reduces contextual modulation
Context provides meaning by influencing perception. In the visual world, context is the visual environment surrounding a visual scene. Here, Keller et al. report that a canonical disinhibitory circuit controls the response of mouse visual cortex to a visual stimulus depending on the context within which that stimulus is presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present a human miRNA tissue atlas by determining the abundance of 1997 miRNAs in 61 tissue biopsies of different organs from two individuals collected post-mortem. One thousand three hundred ...sixty-four miRNAs were discovered in at least one tissue, 143 were present in each tissue. To define the distribution of miRNAs, we utilized a tissue specificity index (TSI). The majority of miRNAs (82.9%) fell in a middle TSI range i.e. were neither specific for single tissues (TSI > 0.85) nor housekeeping miRNAs (TSI < 0.5). Nonetheless, we observed many different miRNAs and miRNA families that were predominantly expressed in certain tissues. Clustering of miRNA abundances revealed that tissues like several areas of the brain clustered together. Considering -3p and -5p mature forms we observed miR-150 with different tissue specificity. Analysis of additional lung and prostate biopsies indicated that inter-organism variability was significantly lower than inter-organ variability. Tissue-specific differences between the miRNA patterns appeared not to be significantly altered by storage as shown for heart and lung tissue. MiRNAs TSI values of human tissues were significantly (P = 10(-8)) correlated with those of rats; miRNAs that were highly abundant in certain human tissues were likewise abundant in according rat tissues. We implemented a web-based repository enabling scientists to access and browse the data (https://ccb-web.cs.uni-saarland.de/tissueatlas).
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