Zum Einfluß der Umweltbedingungen auf die Funktionsweise eines 4-Chlorsalicylat abbauenden mikrobiellen Konsortiums

Biodegradation of recalcitrant xenobiotic pollutants often involves the coordinated action of complex microbial communities. The functioning of a bacterial consortium, that had been isolated for its capability to grow on 4-chlorosalicylate (4-CS), was studied upon environmental perturbations. Genetic and biochemical analysis of Pseudomonas reinekei MT1, the only consortium member that can grow on 4-CS as monoculture, revealed two novel gene clusters. A salicylate 1-hydroxylase, catechol 1,2-dioxygenase and muconate cycloisomerase encoded in the sal gene cluster are specialized for converting methylsubstituted derivatives but also crucial for 4-CS degradation. Genes from the pca cluster encode enzymes of the protocatechuate branch of the 3-oxoadipate pathway essential for channeling of 3-oxoadipate derived from 4-CS degradation into the central metabolism. FISH-flow cytometry enumeration technique was developed to allow quantitative characterisation of the microbial community. In the consortium culture under continuous chemostat conditions strain Achromobacter xylosoxidans MT3 was identified as an abundant member of the community. An increase in dilution rate resulted in a remarkable increase in biomass and in alterations in community composition, with MT3 becoming its predominant member. Thus, the efficiency of 4-CS assimilation depends on the composition of the community and correlates positively with the content of MT3, providing evidence that this strain shares metabolites produced by MT1. Anaerobiosis had a detrimental effect on the functioning of the consortium, where the accumulation of toxic 4-chlorocatechol produced by MT1 resulted in severe alterations of the community composition. Remarkably, under favourable conditions the community was capable to rapidly recover its structure and function. Overall, these experiments indicate that the presence of MT3 in the consortium is crucial for preventing and overcoming environmental perturbations.In dieser Arbeit wurde die Funktion einer 4-Chlorsalicylat (4-CS) abbauenden mikrobiellen Gemeinschaft unter sich verändernden Umweltbedingungen untersucht. Die genetische und biochemische Analyse von Pseudomonas reinekei MT1, der als einziger Stamm der Gemeinschaft befähigt ist, 4-CS in Monokultur zu verwerten, führte zur Identifizierung zweier neuer Gencluster. Das sal Gencluster kodiert für eine Salicylat 1-Hydroxylase, eine Catechol 1,2-Dioxygenase und eine Muconat Cycloisomerase, welche speziell an den Abbau methylsubstituierter Derivative angepasst, aber auch für den Abbau von 4-CS wichtig sind. Die Gene des pca Clusters kodieren für Enzyme des Protocatechuat-Astes des 3-Oxoadipat-Abbauweges und sind entscheidend für das Einleiten von 3-Oxoadipat als Metabolit des 4-CS-Abbaus in den zentralen Stoffwechsel. Durchflusszytometrie/FISH Technik wurde entwickelt, um die Zusammensetzung der Gemeinschaft zu charakterisieren. In kontinuierlicher Kultur des Konsortiums wurde Achromobacter xylosoxidans MT3 als anteilsmäßig häufiges Gemeinschaftsmitglied nachgewiesen. Eine Steigerung der Verdünnungsrate führte zu einem aussergewöhnlichen Anstieg der Biomasse und Veränderungen in der Zusammensetzung der Gemeinschaft mit einer Zunahme an MT3. Somit ist die Effizienz der 4-CS Assimilierung von der Gemeinschaftszusammensetzung abhängig und positiv mit dem Anteil an MT3 korreliert, was darauf hinweist, dass MT3 durch MT1 produzierte Metabolite verwertet. Anaerobiose erwies sich als schädlich für die Funktionsfähigkeit des Konsortiums, da durch den Stamm MT1 produziertes 4-Chlorcatechol zu erheblichen Veränderungen in der Zusammensetzung führte. Bemerkenswerterweise war die Gemeinschaft unter günstigen Bedingungen zu einer raschen Erholung befähigt und erlangte ihre ursprüngliche Zusammensetzung und Funktion. Zusammenfassend deuten die Experimente darauf hin, dass das Vorkommen von MT3 in dem Konsortium für die Prävention und Überwindung von Störeinflüssen nötig ist

Artificial intelligence and computer-aided diagnosis in colonoscopy: current evidence and future directions

Computer-aided diagnosis offers a promising solution to reduce variation in colonoscopy performance. Pooled miss rates for polyps are as high as 22%, and associated interval colorectal cancers after colonoscopy are of concern. Optical biopsy, whereby in-vivo classification of polyps based on enhanced imaging replaces histopathology, has not been incorporated into routine practice because it is limited by interobserver variability and generally only meets accepted standards in expert settings. Real-time decision-support software has been developed to detect and characterise polyps, and also to offer feedback on the technical quality of inspection. Some of the current algorithms, particularly with recent advances in artificial intelligence techniques, match human expert performance for optical biopsy. In this Review, we summarise the evidence for clinical applications of computer-aided diagnosis and artificial intelligence in colonoscopy

Jasmonic acid-dependent regulation of seed dormancy following maternal herbivory in Arabidopsis

Maternal experience of abiotic environmental factors such as temperature and light are well known to control seed dormancy in many plant species. Maternal biotic stress alters offspring defence phenotypes, but whether it also affects seed dormancy remains unexplored. We exposed Arabidopsis thaliana plants to herbivory and investigated plasticity in germination and defence phenotypes in their offspring, along with the roles of phytohormone signalling in regulating maternal effects. Maternal herbivory resulted in the accumulation of jasmonic acid-isoleucine and loss of dormancy in seeds of stressed plants. Dormancy was also reduced by engineering seed-specific accumulation of jasmonic acid in transgenic plants. Loss of dormancy was dependent on an intact jasmonate signalling pathway and was associated with increased gibberellin content and reduced abscisic acid sensitivity during germination. Altered dormancy was only observed in the first generation following herbivory, whereas defence priming was maintained for at least two generations. Herbivory generates a jasmonic acid-dependent reduction in seed dormancy, mediated by alteration of gibberellin and abscisic acid signalling. This is a direct maternal effect, operating independently from transgenerational herbivore resistance priming

A Multi-Lab Test of the Facial Feedback Hypothesis by the Many Smiles Collaboration

Following theories of emotional embodiment, the facial feedback hypothesis suggests that individuals’ subjective experiences of emotion are influenced by their facial expressions. However, evidence for this hypothesis has been mixed. We thus formed a global adversarial collaboration and carried out a preregistered, multicentre study designed to specify and test the conditions that should most reliably produce facial feedback effects. Data from n = 3,878 participants spanning 19 countries indicated that a facial mimicry and voluntary facial action task could both amplify and initiate feelings of happiness. However, evidence of facial feedback effects was less conclusive when facial feedback was manipulated unobtrusively via a pen-in-mouth task

A multi-lab test of the facial feedback hypothesis by the Many Smiles Collaboration

Following theories of emotional embodiment, the facial feedback hypothesis suggests that individuals' subjective experiences of emotion are influenced by their facial expressions. However, evidence for this hypothesis has been mixed. We thus formed a global adversarial collaboration and carried out a preregistered, multicentre study designed to specify and test the conditions that should most reliably produce facial feedback effects. Data from n = 3,878 participants spanning 19 countries indicated that a facial mimicry and voluntary facial action task could both amplify and initiate feelings of happiness. However, evidence of facial feedback effects was less conclusive when facial feedback was manipulated unobtrusively via a pen-in-mouth task

The psychological science accelerator’s COVID-19 rapid-response dataset

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges