Prototypical Components of Honeybee Homing Flight Behavior Depend on the Visual Appearance of Objects Surrounding the Goal

Honeybees use visual cues to relocate profitable food sources and their hive. What bees see while navigating, depends on the appearance of the cues, the bee’s current position, orientation, and movement relative to them. Here we analyze the detailed flight behavior during the localization of a goal surrounded by cylinders that are characterized either by a high contrast in luminance and texture or by mostly motion contrast relative to the background. By relating flight behavior to the nature of the information available from these landmarks, we aim to identify behavioral strategies that facilitate the processing of visual information during goal localization. We decompose flight behavior into prototypical movements using clustering algorithms in order to reduce the behavioral complexity. The determined prototypical movements reflect the honeybee’s saccadic flight pattern that largely separates rotational from translational movements. During phases of translational movements between fast saccadic rotations, the bees can gain information about the 3D layout of their environment from the translational optic flow. The prototypical movements reveal the prominent role of sideways and up- or downward movements, which can help bees to gather information about objects, particularly in the frontal visual field. We find that the occurrence of specific prototypes depends on the bees’ distance from the landmarks and the feeder and that changing the texture of the landmarks evokes different prototypical movements. The adaptive use of different behavioral prototypes shapes the visual input and can facilitate information processing in the bees’ visual system during local navigation

Actively taking part matters: Fostering participation in school lessons digitally with the web app TRAVIS GO

In diesem Artikel wird der digitale Wandel an Schulen zum Ausgangspunkt genommen, um die Konsequenzen des Einsatzes von digitalen Lernwerkzeugen für die Interaktionsstrukturen im schulischen Unterricht aus einer praxeologischen Perspektive zu reflektieren. Es wird für die Entwicklung von digitalen Lernwerkzeugen argumentiert, welche Partizipation und Kollaboration im Unterricht fördern und das strukturierende Lehrerhandeln unterstützen. Als Fallbeispiel dient die Web-App TRAVIS GO und ihr Entwicklungsprozess, in welchen Lehrpersonen aus den Sekundarstufen I und II als Co-Researcher eingebunden waren. TRAVIS GO ist eine App zur kollaborativen Re- und Dekonstruktion von audiovisuellen Medienprodukten. Im didaktischen Design von TRAVIS GO wurden die Anforderungen an problemlösendes, forschendes Lernen und kooperatives Arbeiten erfüllt und die Möglichkeit zum strukturierenden Lehrerhandeln gegeben. TRAVIS GO wird mit Fokus auf die programmseitig angebotenen Möglichkeiten zur Partizipation erstmals systematisch beschrieben und mit den Erfahrungen von Lehrpersonen im Unterrichtseinsatz zusammengebracht, welche im Forschungs- und Entwicklungsprojekt im Rahmen einer empirischen Bildungsforschung gewonnen wurden.This article takes a praxeological perspective on digital change in schools and, hence, on how the use of digital learning tools in school lessons impacts interaction structures in class. We discuss the benefits of developing digital learning tools that foster participation and collaboration among learners and as well allow for teachers’ interventions that help structure the process. As case example, we use the development process of the app TRAVIS GO to which secondary school teachers contributed as co-researchers. TRAVIS GO is an app for collaborative de- and reconstruction of audiovisual media products. Its instructional design allows for problem-based learning and cooperative working methods as well as for guidance by the teacher. We for the first time discuss how TRAVIS GO facilitates participation by relating the app features to experiences of teachers who tested it in class as part of the empirical research project

Identifikacija različito reguliranih proteina nakon infekcije patogenom gljivicom Fusarium graminearum u nekoliko faza sazrijevanja zrna dvozrne pšenice (Triticum dicoccum)

This study was conducted to improve the knowledge of molecular processes involved in the interaction between Fusarium graminearum and emmer in the course of grain ripening. Emmer plants were artificially inoculated with a F. graminearum spore suspension at anthesis. In the course of grain ripening from milk ripe to plant death stage, grains at four phenological growth stages were collected for analysis. The infection degree was evaluated based on the F. graminearum DNA content in emmer grain infolding tissues (glumes and rachis). For proteome analysis the albumin and globulin fractions of emmer grains, consisting of proteins with various functions related to the development and stress response, were analysed regarding the changes due to Fusarium infection by two-dimensional gel electrophoresis. Altogether, forty-three proteins affected by infection were identified by mass spectrometry. Enzymes detoxifying reactive oxygen species were regulated at all developmental stages. In the early stage of grain development, the abundance of proteins related to stress response, such as 2-Cys peroxiredoxin, a chitinase, a xylanase inhibitor and a spermidine synthase was increased. During later stage of grain development, the abundance of stress-related proteins, such as chitinases, heat shock proteins and an α-amylase inhibitor-like protein, decreased. During all ripening stages, but especially during medium milk stage (BBCH 75) and soft dough stage (BBCH 85), the abundance of proteins related to carbon metabolism, starch and protein biosynthesis as well as photosynthesis increased due to F. graminearum infection. At the plant death stage (BBCH 97) the abundance of only two proteins related to metabolism decreased.Ovo je ispitivanje provedeno radi produbljivanja znanja o molekularnim procesima koji se odvijaju u dvozrnoj pšenici inficiranoj gljivicom Fusarium graminearum tijekom sazrijevanja zrna. Dvozrna je pšenica inokulirana suspenzijom spora gljivice F. graminearum u vrijeme cvatnje. Zrnje je prikupljeno za analizu u četiri fenološke faze rasta, od mliječne zrelosti do smrti biljke. Stupanj je infekcije procijenjen prema sadržaju DNA gljivice F. graminearum u pljevi i klasnom vretenu. Pomoću dvodimenzionalne elektroforeze u gelu ispitane su promjene u proteomu pšenice uzrokovane infekcijom gljivicom Fusarium, tj. u albuminskoj i globulinskoj frakciji zrna, sastavljenoj od proteina koji imaju različite uloge u razvoju i odgovoru na stres. Masenom su spektrometrijom identificirana ukupno 43 infekcijom izmijenjena proteina. Enzimi što sudjeluju u uklanjanju reaktivnih kisikovih spojeva bili su regulirani u svim stupnjevima razvoja biljke. U ranoj fazi razvoja zrna pronađen je veći udjel proteina povezanih s odgovorom biljke na stres, kao što su: 2-Cys peroksiredoksin, kitinaza, inhibitor ksilanaze i spermidin sintaza. Tijekom kasnije faze razvoja smanjila se količina proteina vezanih uz odziv biljke na stres kao što su: kitinaze, proteini toplinskog šoka i protein sličan inhibitoru α-amilaze. U svim se fazama sazrijevanja, a naročito tijekom srednje mliječne zrelosti (BBCH 75) i mekane voštane zrelosti (BBCH 85) uslijed zaraze gljivicom F. graminearum povećao udjel proteina vezanih uz metabolizam ugljika, biosintezu proteina i škroba, te fotosintezu. U fazi smrti biljke (BBCH 97) smanjila se količina samo dva proteina vezanih uz metabolizam biljke

The Importance of Detailed Chemical Mechanisms in Gas Turbine Combustion Simulations

This paper – in memory of Jürgen Warnatz – summarizes selected recent papers of the Chemical Kinetics Group at the German Aerospace Center in Stuttgart. It shows the need for detailed chemical reaction mechanisms to understand practical combustion systems. A comprehensive description of combustion processes based on detailed mechanisms is especially important in the design of new gas turbine combustion chambers and in the optimization of existing ones to improve efficiency and to reduce pollutant emissions, with fuel-flexibility and load-flexibility ever becoming more important. Different aspects of combustion processes where detailed reaction mechanisms provide useful insights will be covered in this paper: Fuels (alternative jet fuels, biomass based fuels), pollutants (soot), diagnostics (chemiluminescence), and thermochemistry. Furthermore, the underlying thermodynamics inevitably connected with detailed reaction schemes will be addressed. Exemplified results will be presented clearly demonstrating the predictive capabilities of detailed reaction mechanisms to be explored in computational fluid dynamic simulations to further optimize technical combustion systems

Neubauten im historischen Kontext

NEUBAUTEN IM HISTORISCHEN KONTEXT Neubauten im historischen Kontext / Braun, Jascha Philipp (Rights reserved) ( -

Fast, economic and simultaneous identification of clinically relevant Gram-negative species with multiplex real-time PCR

Aim: A newly designed multiplex real-time PCR (rt-PCR) was validated to detect four clinically relevant Gram-negative bacteria (Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa). Materials & methods: Serial dilutions of genomic DNA were used to determine the limit of detection. Colony PCR was performed with isolates of the four selected species and other species as negative controls. Isolates were characterized genotypically and phenotypically to evaluate the assay. Results: Specific signals of all target genes were detected with diluted templates comprising ten genomic equivalents. Using colony rt-PCR, all isolates of the target species were identified correctly. All negative control isolates were negative. Conclusion: The genes gad, basC, khe and ecfX can reliably identify these four species via multiplex colony rt-PCR. © 2018 Daniel Weiss

Characterisation of Methicillin-Resistant Staphylococcus aureus from Alexandria, Egypt

The present study aims to characterise clinical MRSA isolates from a tertiary care centre in Egypt’s second-largest city, Alexandria. Thirty isolates collected in 2020 were genotypically characterised by microarray to detect their resistance and virulence genes and assign them to clonal complexes (CC) and strains. Isolates belonged to 11 different CCs and 14 different strains. CC15-MRSA-[V+fus] (n = 6), CC1-MRSA-[V+fus+tir+ccrA/B-1] (PVL+) (n = 5) as well as CC1-MRSA-[V+fus+tir+ccrA/B-1] and CC1153-MRSA-[V+fus] (PVL+) (both with n = 3) were the most common strains. Most isolates (83%) harboured variant or composite SCCmec V or VI elements that included the fusidic acid resistance gene fusC. The SCCmec [V+fus+tir+ccrA/B-1] element of one of the CC1 isolates was sequenced, revealing a presence not only of fusC but also of blaZ, aacA-aphD and other resistance genes. PVL genes were also common (40%). The hospital-acquired MRSA CC239-III strain was only found twice. A comparison to data from a study on strains collected in 2015 (Montelongo et al., 2022) showed an increase in fusC and PVL carriage and a decreasing prevalence of the CC239 strain. These observations indicate a diffusion of community-acquired strains into hospital settings. The beta-lactam use in hospitals and the widespread fusidic acid consumption in the community might pose a selective pressure that favours MRSA strains with composite SCCmec elements comprising mecA and fusC. This is an unsettling trend, but more MRSA typing data from Egypt are required

Extracellular calcium reduction strongly increases the lytic capacity of pneumolysin from streptococcus pneumoniae in brain tissue

Background. Streptococcus pneumoniae causes serious diseases such as pneumonia and meningitis. Its major pathogenic factor is the cholesterol-dependent cytolysin pneumolysin, which produces lytic pores at high concentrations. At low concentrations, it has other effects, including induction of apoptosis. Many cellular effects of pneumolysin appear to be calcium dependent. Methods. Live imaging of primary mouse astroglia exposed to sublytic amounts of pneumolysin at various concentrations of extracellular calcium was used to measure changes in cellular permeability (as judged by lactate dehydrogenase release and propidium iodide chromatin staining). Individual pore properties were analyzed by conductance across artificial lipid bilayer. Tissue toxicity was studied in continuously oxygenated acute brain slices. Results. The reduction of extracellular calcium increased the lytic capacity of the toxin due to increased membrane binding. Reduction of calcium did not influence the conductance properties of individual toxin pores. In acute cortical brain slices, the reduction of extracellular calcium from 2 to 1 mM conferred lytic activity to pathophysiologically relevant nonlytic concentrations of pneumolysin. Conclusions. Reduction of extracellular calcium strongly enhanced the lytic capacity of pneumolysin due to increased membrane binding. Thus, extracellular calcium concentration should be considered as a factor of primary importance for the course of pneumococcal meningitis

Molecular investigations on a chimeric strain of Staphylococcus aureus sequence type 80

A PVL-positive, methicillin-susceptible Staphylococcus aureus was cultured from pus from cervical lymphadenitis of a patient of East-African origin. Microarray hybridisation assigned the isolate to clonal complex (CC) 80 but revealed unusual features, including the presence of the ORF-CM14 enterotoxin homologue and of an ACME-III element as well as the absence of etD and edinB. The isolate was subjected to both, Illumina and Nanopore sequencing allowing characterisation of deviating regions within the strain´s genome. Atypical features of this strain were attributable to the presence of two genomic regions that originated from other S. aureus lineages and that comprised, respectively, 3% and 1.4% of the genome. One deviating region extended from walJ to sirB. It comprised ORF-CM14 and the ACME-III element. A homologous but larger fragment was also found in an atypical S. aureus CC1/ST567 strain whose lineage might have served as donor of this genomic region. This region itself is a chimera comprising fragments from CC1 as well as fragments of unknown origin. The other deviating region comprised the region from htsB to ecfA2, i.e., another 3% of the genome. It was very similar to CC1 sequences. Either this suggests an incorporation of CC1 DNA into the study strain, or alternatively a recombination event affecting “canonical” CC80. Thus, the study strain bears witness of several recombination events affecting supposedly core genomic genes. Although the exact mechanism is not yet clear, such chimerism seems to be an additional pathway in the evolution of S. aureus. This could facilitate also a transmission of virulence and resistance factors and therefore offer an additional evolutionary advantage