Genetically encoded thiol redox-sensors in the zebrafish model: Lessons for embryonic development and regeneration

Important roles for reactive oxygen species (ROS) and redox signaling in embryonic development and regenerative processes are increasingly recognized. However, it is difficult to obtain information on spatiotemporal dynamics of ROS production and signaling in vivo. The zebrafish is an excellent model for in vivo bioimaging and possesses a remarkable regenerative capacity upon tissue injury. Here, we review data obtained in this model system with genetically encoded redox-sensors targeting H$_{2}$O$_{2}$ and glutathione redox potential. We describe how such observations have prompted insight into regulation and downstream effects of redox alterations during tissue differentiation, morphogenesis and regeneration. We also discuss the properties of the different sensors and their consequences for the interpretation of in vivo imaging results. Finally, we highlight open questions and additional research fields that may benefit from further application of such sensor systems in zebrafish models of development, regeneration and disease

О наведенной активности при дефектоскопии толстых стальных изделий с помощью тормозного излучения бетатрона

В статье рассматривается образование наведенной активности в стальных изделиях в результате возникновения фотоядерных реакций на изотопах элементов, входящих в состав сталей при дефектоскопии изделий тормозным излучением бетатрона с максимальной энергией Е? = 30-35 Мэв. Определяются мощности доз ? и ?-излучений радиоактивных изотопов вблизи поверхности изделий. Проведены результаты экспериментального определения наведенной активности в стали

Stem cells and the circadian clock

The circadian timing system is a complex biological network of interacting circadian clocks that regulates 24 h rhythms of behavioral and physiological processes. One intriguing observation is that stem cell homeostasis is subject to circadian clock regulation. Rhythmic oscillations have been observed in a variety of embryonic and adult stem cell dependent processes, such as hematopoietic progenitor cell migration, the hair follicle cycle, bone remodeling, regenerative myogenesis and neurogenesis. This review aims to discuss the nature of the circadian clock in embryonic stem cells and how it changes during differentiation. Furthermore, it will examine how the circadian clock contributes to adult stem cell function in different tissues of the body with an emphasis on the brain and adult neurogenesis

Inductively coupled magic angle spinning microresonators benchmarked for high-resolution single embryo metabolomic profiling

The magic angle coil spinning (MACS) technique has been introduced as a very promising extension for solid state NMR detection, demonstrating sensitivity enhancements by a factor of 14 from the very first time it has been reported. The main beneficiary of this technique is the scientific community dealing with mass- and volume-limited, rare, or expensive samples. However, more than a decade after the first report on MACS, there is a very limited number of groups who have continued to develop the technique, let alone it being widely adopted by practitioners. This might be due to several drawbacks associated with the MACS technology until now, including spectral linewidth, heating due to eddy currents, and imprecise manufacturing. Here, we report a device overcoming all these remaining issues, therefore achieving: (1) spectral resolution of approx 0.01 ppm and normalized limit of detection of approx. 13 nmol s⁰·⁵calculated using the anomeric proton of sucrose at 3 kHz MAS frequency; (2) limited temperature increase inside the MACS insert of only 5 °C at 5 kHz MAS frequency in an 11.74 T magnetic field, rendering MACS suitable to study live biological samples. The wafer-scale fabrication process yields MACS inserts with reproducible properties, readily available to be used on a large scale in bio-chemistry labs. To illustrate the potential of these devices for metabolomic studies, we further report on: (3) ultra-fine ¹H–¹H and ¹³C–¹³C J-couplings resolved within 10 min for a 340 mM uniformly ¹³C-labeled glucose sample; and (4) single zebrafish embryo measurements through ¹H–¹H COSY within 4.5 h, opening the gate for the single embryo NMR studies

Automated phenotype pattern recognition of zebrafish for high-throughput screening

Over the last years, the zebrafish (Danio rerio) has become a key model organism in genetic and chemical screenings. A growing number of experiments and an expanding interest in zebrafish research makes it increasingly essential to automatize the distribution of embryos and larvae into standard microtiter plates or other sample holders for screening, often according to phenotypical features. Until now, such sorting processes have been carried out by manually handling the larvae and manual feature detection. Here, a prototype platform for image acquisition together with a classification software is presented. Zebrafish embryos and larvae and their features such as pigmentation are detected automatically from the image. Zebrafish of 4 different phenotypes can be classified through pattern recognition at 72 h post fertilization (hpf), allowing the software to classify an embryo into 2 distinct phenotypic classes: wild-type versus variant. The zebrafish phenotypes are classified with an accuracy of 79–99% without any user interaction. A description of the prototype platform and of the algorithms for image processing and pattern recognition is presented

Molecular integration of casanova in the Nodal signalling pathway controlling endoderm formation

International audienceEndoderm originates from a large endomesodermal field requiring Nodal signalling. The mechanisms that ensure segregation of endoderm from mesoderm are not fully understood. We first show that the timing and dose of Nodal activation are crucial for endoderm formation and the endoderm versus mesoderm fate choice, because sustained Nodal signalling is required to ensure endoderm formation but transient signalling is sufficient for mesoderm formation. In zebrafish, downstream of Nodal signals, three genes encoding transcription factors (faust, bonnie and clyde and the recently identified gene casanova) are required for endoderm formation and differentiation. However their positions within the pathway are not completely established. In the present work, we show that casanova is the earliest specification marker for endodermal cells and that its expression requires bonnie and clyde. Furthermore, we have analysed the molecular activities of casanova on endoderm formation and found that it can induce endodermal markers and repress mesodermal markers during gastrulation, as well as change the fate of marginal blastomeres to endoderm. Overexpression of casanova also restores endoderm markers in the absence of Nodal signalling. In addition, casanova efficiently restores later endodermal differentiation in these mutants, but this process requires, in addition, a partial activation of Nodal signalling

Природный минерал шунгит и его использование для очистки сточных вод от различных загрязнителей

В данной статье исследуется природный минерал шунгит Зажогинского месторождения (Карелия). Данный минерал имеет характерную для шунгита морфологию, однороден. На поверхности присутствуют характерные для шунгита ступенчатые сколы. В минерале присутствуют включения разного элементного состава: углерод, кислород, кремний, ванадий, алюминий, сера, цинк, калий. Наличие данных элементов также характерно для природного шунгита.This article explores the natural mineral shungite of the Zazhoginsky deposit (Karelia). This mineral has a morphology characteristic of shungite, homogeneous. On the surface, there are stepped chips characteristic of shungite. The mineral contains inclusions of different elemental composition: carbon, oxygen, silicon, vanadium, aluminum, sulfur, zinc, potassium. The presence of these elements is also characteristic of natural shungite

Neue Wege der linguistischen Diskursforschung: computerbasierte Verfahren der Argumentanalyse

Der vorliegende Beitrag beschreibt und diskutiert eine neuartige Verbindung quantitativer und qualitativer Verfahren für die Analyse von Big Data in der linguistischen Diskursforschung. Der vorgestellte Ansatz kombiniert Methoden der diskurslinguistischen Argumentationsanalyse mit Methoden des Linguistischen Text Mining. Das Ziel der Methodenentwicklung ist ein computergestütztes Verfahren für die semi-automatisierte Identifizierung und Analyse von Argumenten in großen Textkorpora. Erprobt wird das Verfahren an einem Diskurs über Infrastrukturmaßnahmen. Im Beitrag werden sprachliche Mittel vorgestellt, die im Korpus gemeinsam auftreten und damit als Merkmale von Argumentmustern betrachtet werden können. Solche Argumentmuster können das Vorkommen von Argumenten und ihren Verwendungsweisen in Texten indizieren