Comprehensive analysis of C. glutamicum anaplerotic deletion mutants under defined d-glucose conditions

Wild-type C. glutamicum ATCC 13032 is known to possess two enzymes with anaplerotic (C4-directed) carboxylation activity, namely phosphoenolpyruvate carboxylase (PEPCx) and pyruvate carboxylase (PCx). On the other hand, C3-directed decarboxylation can be catalyzed by the three enzymes phosphoenolpyruvate carboxykinase (PEPCk), oxaloacetate decarboxylase (ODx), and malic enzyme (ME). The resulting high metabolic flexibility at the anaplerotic node compromises the unambigous determination of its carbon and energy flux in C. glutamicum wild type. To circumvent this problem we performed a comprehensive analysis of selected single or double deletion mutants in the anaplerosis of wild-type C. glutamicum under defined d-glucose conditions. By applying well-controlled lab-scale bioreactor experiments in combination with untargeted proteomics, quantitative metabolomics and whole-genome sequencing hitherto unknown, and sometimes counter-intuitive, genotype-phenotype relationships in these mutants could be unraveled. In comparison to the wild type the four mutants C. glutamiucm Δpyc, C. glutamiucm Δpyc Δodx, C. glutamiucm Δppc Δpyc, and C. glutamiucm Δpck showed lowered specific growth rates and d-glucose uptake rates, underlining the importance of PCx and PEPCk activity for a balanced carbon and energy flux at the anaplerotic node. Most interestingly, the strain C. glutamiucm Δppc Δpyc could be evolved to grow on d-glucose as the only source of carbon and energy, whereas this combination was previously considered lethal. The prevented anaplerotic carboxylation activity of PEPCx and PCx was found in the evolved strain to be compensated by an up-regulation of the glyoxylate shunt, potentially in combination with the 2-methylcitrate cycle

Concept for an Onboard Integrated PNT Unit

A robust electronic position, navigation and timing system (PNT) is considered as one of the core elements for the realization of IMO-s (International Maritime Organization) e-Navigation strategy. Robustness can be interpreted as the capability of an integrated PNT system to provide PNT relevant data with the desired accuracy, integrity, continuity and availability under consideration of changing application conditions and requirements. Generally an integrated PNT system is a composite of service components – like GNSS, Augmentation Systems and terrestrial Navigation Systems – and an on-board integrated PNT Unit, which uses the available navigation and augmentation signals in combination with additional data of sensors aboard to provide accurate and robust PNT information of the ship. In this paper a concept of such an on-board integrated PNT Unit will be presented, which is designed to fulfill the specific user requirements for civil waterway applications. At first, the user requirements for an integrated PNT Unit will be overviewed. After that, existing integrity monitoring approaches will be analyzed. Finally, a first integration scheme for an inte-grated PNT Unit will be presented with a special focus on the internal integrity monitoring concept

The on-board maritime PNT Module –Integrity monitoring aspects and first experimental results

This paper focuses on a maritime integrated PNT Module as the on-board part of maritime PNT system. The aim of the PNT Module is the robust provision of position, navigation and timing information in accordance with the performance requirements of the actual operational region. The core of the PNT Module is a PNT Unit. This PNT Unit is a processing system, which combines by means of sensor and data fusion methods all available PNT sensors. The PNT Module is on the one hand part of the integrated PNT System and on the other hand part of the on- board INS. After a short discussion of the sensors of a PNT Module we have introduced a preliminary integrity monitoring concept for a PNT Module. In a first step towards the development of a PNT Module demonstrator system we have performed first measurement campaigns and derived PNT output data from different sensors. The analysis of these data shows, that for their usage within compatibility tests, the different locations of the sensors onboard the vessel needs to be considered

Concept for an Integrated PNT-Unit for Maritime Applications

The provision of robust position, navigation and timing (PNT) information is a fundamental element of the e-Navigation initiative proposed by the International Maritime Organization (IMO). In this context the single Electronic Position Fixing System (EPFS), which currently conforms to the minimum carriage requirement, should be replaced by an integrated PNT unit as future onboard integrated system. This unit has the task to collect and integrate data from individual PNT sensors in order to deliver robust PNT information with a specified performance. In this paper the current status of PNT sensors for maritime application is reviewed and first ideas towards an integrity concept for a maritime PNT unit are presented

The on-board maritime PNT Module – Concept and preliminary experimental results

Improvement and Indication of Reliability have been identified as important user needs within the e-Navigation strategy of the International Maritime Organization (IMO). This paper address the question, how these user needs can be satisfied in future with respect to resilient provision of position navigation and timing (PNT) data onboard the vessel. The idea of an onboard PNT Module is proposed as front-end between an integrated PNT system and ship-side applications like INS, AIS and ECDIS. The paper focuses on the integrity monitoring within the PNT Module. The concept is introduced and first experimental results are presented

Resilient Position, Navigation and Timing (PNT) Unit as part of the maritime Integrated Navigation System (INS)

With respect to "GNSS in marine appications" the presentation was used to discuss some fundamental aspects concerning the new proposed resilient PNT unit as well as the role of integrity within the maritime community

Maritimes PNT-System: Ansätze für ein koordiniertes Integritätsmonitoring und -management

In den letzten Jahrzehnten haben sich Globale Navigationssatellitensysteme (GNSS) als satellitengestützte Infrastruktur etabliert, mit der weltweit Positions-, Geschwindigkeits- und Zeitdaten (PVT) in allen Verkehrsbereichen bestimmt werden. Für die Schiffsnavigation sind neben den PVT-Daten auch Navigationsdaten (N) notwendig, mit denen die dreidimensionale Lage und Bewegung eines Fahrzeuges geplant, bestimmt und in Relation zur Umgebung überwacht werden kann. Navigationsdaten in diesem Kontext sind u.a. Heading, Rate of Turn (RoT) und Course over Ground (CoG), die für ein sicheres Passieren von Engstellen (Kanäle, Brücken) und ein effizientes Anlegen in Häfen gleichermaßen erforderlich sind. Höchste Anforderungen an die Datensicherheit sind zu erwarten, wenn die PNT-Daten als Eingangsdaten für automatisierte oder teilautomatisierte Steuerungs- und Regelungsprozesse dienen sollen. Integrität ist ein klassisches Ziel der Informationssicherheit und gilt als erfüllt, wenn Systeme entsprechend ihrer Spezifikation funktionieren. Ein System, dessen Aufgabe es ist, Informationen in Form von Daten bereitzustellen, funktioniert spezifikationsgerecht, wenn die Daten im gewünschten Umfang mit der geforderten Qualität zur Verfügung gestellt werden konnten. Die Integrität des maritimen PNT-Systems ist folglich an der Qualität bereitgestellter PNT-Daten zu messen. Im maritimen Verkehrssystem wird ein erweiterter Integritätsbegriff genutzt, der die Fähigkeit eines Systems einschließt, seine Integrität (Nutzbarkeit) selbst bewerten und Nutzer darüber in Echtzeit informieren zu können. Am Anfang wird das maritime PNT-System anhand seiner Architektur und in diesem Kontext genutzter und nutzbarer Infrastrukturen, Diensten und Sensoren kurz skizziert. Verfahren, mit denen derzeit eine Integritätsüberwachung im maritimen PNT-System erfolgt, werden beschrieben und hinsichtlich ihrer Leistungsfähigkeit charakterisiert. Im Folgeschritt werden Konzepte herausgearbeitet und diskutiert, die als Lösungsansätze für ein koordiniertes Integritätsmonitoring im maritimen PNT-System dienen könnten

Herausforderung an die maritime Kommunikation: Integritätsüberwachung in verteilten Systemen am Beispiel des PNT-Systems

The presentation describes requirements on the maritime communication system resulting from the aimed introduction of integrity into the marime position, navigation, and timing system (PNT)

Resilient PNT: From PNT-Unit concept to first realization

Resilient determination of position, navigation and time (PNT) data of the vessel has been recognized as one core element of IMO’s e-Navigation strategy. As an associated member of the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), the German Aerospace Center (DLR) is proposing the introduction of a shipside PNT Module as part of a future Integrated Navigation System (INS). The core of the ship side PNT Module is a sensor fusion based processing system (PNT Unit) using available radio navigation systems and services in combination with on-board sensors for PNT data generation. A focus of the PNT Unit is provision of integrity information for all PNT data in accordance with changing performance requirements during berth to berth navigation. Within the Maritime Traffic Engineering project the development of a first prototype of such a PNT Unit has been started in order to demonstrate the feasibility of such a PNT Unit. This paper will shortly introduce the basic concept of the PNT Module. The focus here will lie on the discussion on open regulatory aspects which have been raised during the prototype development. Secondly the results of a first realization of a PNT Unit will be presented. In the last part an overview of our latest developments of the shore based services at the Research Port Rostock will be given