Expression, localization, and interaction studies of the plastidic PII protein from Arabidopsis thaliana

The perception and regulation of the cellular content of nitrogen (N) and carbon (C) is essential for all living organisms. Though the superfamily of PII proteins that are highly conserved in bacteria, archaea, algae and plants, ought to play a crucial role. It is assumed from studies in bacteria that PII is a sensor of the nitrogen and carbon status Although the function of PII in bacteria is well characterised (Forchhammer and Selim, 2019), little is known about these function in plants and especially in A. thaliana. To understand the function of A. thaliana PII, I focussed on expression, localization, and interaction studies. Here I show that PII mRNA expression changes dependent on inorganic nitrogen under constant light. Physiological studies on PII knockdown mutants, and in addition with PII overexpression lines, revealed no evidence for the deregulation of the C/N-metabolism. This observation let appear a central role of the PII-protein for these processes in plants less probable. Furthermore, I could show that PII localizes to foci in plastids and in extraplastidic vesicle-like structures, which could be related to protein turnover. Further, I could exclude that PII localizes to nucleoids and starch granules. I could show that A. thaliana PII co-localizes not only with the already known interaction partners N-acetyl-L-glutamate kinase (NAGK), the biotin carboxyl carrier protein 1 (BCCP1) and with the biotin/lipoyl attachment domain containing (BADC) proteins BADC2/3 in plastids but in addition with Granule-bound Starch Synthase I (GBSSI), D-Amino Acid Transaminase 1 (DAT1), one of the small Rubisco subunits RBCS3B, and Deoxyxylulose synthase (DXS), Deoxyxylulose reductoisomerase (DXR) and partially with the Geranylgeranyl diphosphate synthase 11 (GGPPS11). Using FRET-FLIM and BiFC studies, even an interaction of PII with itself, NAGK, BCCP1, GBSSI, DAT1, RBCS3B, DXS and DXR could be observed. The localization pattern and interactions observed for A. thaliana PII indicate further unknown regulatory functions of PII in A. thaliana

Lebensmittelwerbung für Kinderprodukte: Strategieentwürfe für den vorbeugenden Verbraucherschutz

"Der Bericht dient der Darstellung der Ergebnisse zum Projekt 'Lebensmittelwerbung für Kinderprodukte - Strategieentwürfe für den vorbeugenden Verbraucherschutz'. Das Vorhaben stellt den rechtlichen Rahmen für Lebensmittelwerbung vor Kindern, die aktuellen Erkenntnisse der Ernährungswissenschaft und die werbepsychologischen bzw. sozialpsychologischen Grundlagen dar und vergleicht diese exemplarisch mit der aktuellen Lebensmittelwerbung für die Zielgruppe Kinder. Die Datenbank erfasst die Art der Darstellung und Aussagen, eine Beurteilung der beworbenen Produkte aufgrund der Energiedichte und der glykämischen Last in Verbindung mit dem Sättigungswert und die Verstöße der Hersteller gegen Regeln, die aus gesetzlichen Vorschriften abgeleitet werden können und Regeln des deutschen Werberates. Die daraus entstehende empirische Basis belegt das Ausmaß und die Qualität der Lebensmittelwerbung für Kinderprodukte und stellt somit das Maß für die Verantwortung der Werbetreibenden und den Regelungsbedarf dar. Ausgehend davon dient die anschließende Institutionenanalyse einer geeigneten Strategieentwicklung in diesem Politikfeld. Dabei geht es darum, dass das erforderliche Schutzniveau durch möglichst eingriffsarme Instrumente zu gewährleisten ist. Die Art der in dieser Hinsicht optimalen Eingriffsinstrumente (Verbote, Auflagen, Abgabenlösungen, Informationspflichten, etc.) hängt ab von der Größe der Akteursgruppen, dem zu behebenden Regulierungsproblem sowie den instrumentellen Rahmenbedingungen.(...)" (Autorenreferat

Towards a critical epidemiology approach for applied sexual health research

Critical approaches may benefit epidemiological studies of sexual health. This article proposes a critical approach, reconcilable with social epidemiological enquiry. Key aims of critical epidemiology for sexual health are identified, from which three criticisms of practice emerge: (1) lack of attention to socio-cultural contexts, (2) construction of 'risk' as residing in the individual and (3) enactment of public health agendas which privilege and pathologise certain behaviours. These reflect and construct an apolitical understanding of population health. This article proposes features of a critical epidemiology that represent a morally driven re-envisioning of the focus, analysis and interpretation of epidemiological studies of sexual health

Immune System Dysregulation During Spaceflight: Potential Countermeasures for Deep Space Exploration Missions

Recent studies have established that dysregulation of the human immune system and the reactivation of latent herpesviruses persists for the duration of a 6-month orbital spaceflight. It appears certain aspects of adaptive immunity are dysregulated during flight, yet some aspects of innate immunity are heightened. Interaction between adaptive and innate immunity also seems to be altered. Some crews experience persistent hypersensitivity reactions during flight. This phenomenon may, in synergy with extended duration and galactic radiation exposure, increase specific crew clinical risks during deep space exploration missions. The clinical challenge is based upon both the frequency of these phenomena in multiple crewmembers during low earth orbit missions and the inability to predict which specific individual crewmembers will experience these changes. Thus, a general countermeasure approach that offers the broadest possible coverage is needed. The vehicles, architecture, and mission profiles to enable such voyages are now under development. These include deployment and use of a cis-Lunar station (mid 2020s) with possible Moon surface operations, to be followed by multiple Mars flyby missions, and eventual human Mars surface exploration. Current ISS studies will continue to characterize physiological dysregulation associated with prolonged orbital spaceflight. However, sufficient information exists to begin consideration of both the need for, and nature of, specific immune countermeasures to ensure astronaut health. This article will review relevant in-place operational countermeasures onboard ISS and discuss a myriad of potential immune countermeasures for exploration missions. Discussion points include nutritional supplementation and functional foods, exercise and immunity, pharmacological options, the relationship between bone and immune countermeasures, and vaccination to mitigate herpes (and possibly other) virus risks. As the immune system has sentinel connectivity within every other physiological system, translational effects must be considered for all potential immune countermeasures. Finally, we shall discuss immune countermeasures in the context of their individualized implementation or precision medicine, based on crewmember specific immunological biases

A Census of Early Phase High-Mass Star Formation in the Central Molecular Zone

We present new observations of C-band continuum emission and masers to assess high-mass ($>$8 $M_\odot$) star formation at early evolutionary phases in the inner 200 pc of the Central Molecular Zone (CMZ) of the Galaxy. The continuum observation is complete to free-free emission from stars above 10-11 $M_\odot$ in 91% of the covered area. We identify 104 compact sources in the continuum emission, among which five are confirmed ultracompact H II regions, 12 are candidates of ultra-compact H II regions, and the remaining 87 sources are mostly massive stars in clusters, field stars, evolved stars, pulsars, extragalactic sources, or of unknown nature that is to be investigated. We detect class II CH$_3$OH masers at 23 positions, among which six are new detections. We confirm six known H$_2$CO masers in two high-mass star forming regions, and detect two new H$_2$CO masers toward the Sgr C cloud, making it the ninth region in the Galaxy that contains masers of this type. In spite of these detections, we find that current high-mass star formation in the inner CMZ is only taking place in seven isolated clouds. The results suggest that star formation at early evolutionary phases in the CMZ is about 10 times less efficient than expected by the dense gas star formation relation, which is in line with previous studies that focus on more evolved phases of star formation. This means that if there will be any impending, next burst of star formation in the CMZ, it has not yet begun

Arabidopsis PII Proteins Form Characteristic Foci in Chloroplasts Indicating Novel Properties in Protein Interaction and Degradation

The PII protein is an evolutionary, highly conserved regulatory protein found in both bacteria and higher plants. In bacteria, it modulates the activity of several enzymes, transporters, and regulatory factors by interacting with them and thereby regulating important metabolic hubs, such as carbon/nitrogen homeostasis. More than two decades ago, the PII protein was characterized for the first time in plants, but its physiological role is still not sufficiently resolved. To gain more insights into the function of this protein, we investigated the interaction behavior of AtPII with candidate proteins by BiFC and FRET/FLIM in planta and with GFP/RFP traps in vitro. In the course of these studies, we found that AtPII interacts in chloroplasts with itself as well as with known interactors such as N-acetyl-L-glutamate kinase (NAGK) in dot-like aggregates, which we named PII foci. In these novel protein aggregates, AtPII also interacts with yet unknown partners, which are known to be involved in plastidic protein degradation. Further studies revealed that the C-terminal component of AtPII is crucial for the formation of PII foci. Altogether, the discovery and description of PII foci indicate a novel mode of interaction between PII proteins and other proteins in plants. These findings may represent a new starting point for the elucidation of physiological functions of PII proteins in plants

<i>Arabidopsis</i> PII Proteins Form Characteristic Foci in Chloroplasts Indicating Novel Properties in Protein Interaction and Degradation

The PII protein is an evolutionary, highly conserved regulatory protein found in both bacteria and higher plants. In bacteria, it modulates the activity of several enzymes, transporters, and regulatory factors by interacting with them and thereby regulating important metabolic hubs, such as carbon/nitrogen homeostasis. More than two decades ago, the PII protein was characterized for the first time in plants, but its physiological role is still not sufficiently resolved. To gain more insights into the function of this protein, we investigated the interaction behavior of AtPII with candidate proteins by BiFC and FRET/FLIM in planta and with GFP/RFP traps in vitro. In the course of these studies, we found that AtPII interacts in chloroplasts with itself as well as with known interactors such as N-acetyl-L-glutamate kinase (NAGK) in dot-like aggregates, which we named PII foci. In these novel protein aggregates, AtPII also interacts with yet unknown partners, which are known to be involved in plastidic protein degradation. Further studies revealed that the C-terminal component of AtPII is crucial for the formation of PII foci. Altogether, the discovery and description of PII foci indicate a novel mode of interaction between PII proteins and other proteins in plants. These findings may represent a new starting point for the elucidation of physiological functions of PII proteins in plants

Effect of Isocyanate Absorption on the Mechanical Properties of Silicone Elastomers in Polyurethane Vacuum Casting.

Wortmann M, Krieger P, Frese N, Moritzer E, Husgen B. Effect of Isocyanate Absorption on the Mechanical Properties of Silicone Elastomers in Polyurethane Vacuum Casting. ACS omega. 2021;6(7):4687–4695.Polyurethane vacuum casting with silicone molds is a widely used industrial process for the production of prototypes and small batches. Since the silicone casting molds absorb the isocyanate component of the curing PUR casting resin at the cavity surface, the service life of the molds is typically restricted to very few casting cycles. The successive deterioration of the material properties results from the polymerization of the absorbed isocyanate with moisture to polyurea derivatives within the silicone matrix. In this study, we show for the first time the influence of isocyanate absorption on the mechanical properties of silicone elastomers as well as quantitative differences between commercial materials. The changes in mechanical properties were quantified in terms of Shore A hardness, Young's modulus, tensile strength, elongation at break, and complex shear modulus. It was found that the influence of the isocyanate type on the relative property changes of the silicone was significantly greater than that of the silicone used. The results show that, regardless of its hardness, the silicone absorbs considerably less methylene diphenyl diisocyanate (MDI) than hydrogenated MDI, although the latter causes less deterioration of the mechanical properties and achieves a longer mold service life. © 2021 The Authors. Published by American Chemical Society