Bulk organic aerosol analysis by PTR-MS: an improved methodology for the determination of total organic mass, O:C and H:C ele- mental ratios and the average molecular formula

International audienceWe have recently shown in this journal (Müller et al., Anal. Chem. 2017, 89, 10889-10897) how a proton-transfer-reaction mass spectrometry (PTR-MS) analyzer measured particulate organic matter in urban atmospheres using the "Chemical Analysis of Aerosol Online" (CHARON) inlet. Our initial CHARON studies did not take into account fragmentation of protonated analyte molecules, which introduced a small but significant negative bias in the determination of bulk organic aerosol parameters. Herein, we studied the ionic fragmentation of 26 oxidized organic compounds typically found in atmospheric particles. This allowed us to derive a correction algorithm for the determination of the bulk organic mass concentration, m OA , the bulk-average hydrogen to carbon ratio, (H:C) bulk, the bulk-average oxygen-to-carbon, (O:C) bulk , and the bulk-average molecular formula, MF bulk. The correction algorithm was validated against AMS data using two sets of published data. Finally, we determined MF bulk of particles generated from the reaction of -pinene and ozone and compared and discussed the results in relation to the literature

Preliminary assessment of the imaging capability of the YAP-(S)PET small animal scanner in neuroscience

The new and fully engineered version of the YAP–(S)PET small animal scanner has been tested at the University of Mainz for preliminary assessment of its imaging capability for studies related to neuropharmacology and psychiatry. The main feature of the scanner is the capability to combine PET and SPECT techniques. It allows the development of new and interesting protocols for the investigation of many biological phenomena, more effectively than with PET or SPECT modalities alone. The scanner is made up of four detector heads, each one composed of a 4 � 4c m 2 of YAlO3:Ce (or YAP:Ce) matrix, and has a field of view (FOV) of 4 cm axially � 4c m + transaxially. In PET mode, the volume resolution is less than 8 mm 3 and is nearly constant over the whole FOV, while the sensitivity is about 2%. The SPECT performance is not so good, due to the presence of the multi-hole lead collimator in front of each head. Nevertheless, the YAP–PET scanner offers excellent resolution and sensitivity for performing on the availability of D2-like dopamine receptors on mice and rats in both PET and SPECT modalities

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Minimum Information about a Biosynthetic Gene cluster

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.Chemistry and Chemical Biolog

Synthese, n.c.a. 18F-Markierung und Evaluierung von Antagonisten der Strychnin-unempfindlichen-Glycinbindungsstelle auf Basis der 4- Amino-5,7-Dichlor-1,2,3,4-Tetrahydro-Chinolin-2-Carbonsäure

ZUSAMMENFASSUNGDer glutamaterge N-Methyl-D-aspartat-Rezeptor (NMDA) ist ein wichtiger ionotroper Rezeptor, der die exzitatorische synaptische Transmission im zentralen Nervensystem von Säugetieren vermittelt. Der NMDA-Rezeptor nimmt unter den Glutamatrezeptoren dabei eine Sonderstellung ein, da er mit einer Reihe von neurodegenerativen Erkrankungen wie dem Morbus Parkinson, dem Morbus Huntington, dem Morbus Alzheimer, der Schizophrenie und der Epilepsie in Zusammenhang gebracht wird. Daher besteht ein großes Interesse an der Entwicklung geeigneter 18F-markierter NMDA-Rezeptorliganden zur nicht-invasiven Visualisierung des NMDA-Rezeptorkomplexes mittels der Positronenemissionstomographie.Die 19F-Analoga ADTC1, tADTC1 und tADTC3 - 5 und das nicht-fluorierte 12C-Analogon tADTC2 wurden synthetisiert und ihre in-vitro Affinität und Lipophilie bestimmt. Mit Ausnahme von ADTC1 und tADTC5 die mikromolare Affinitäten besitzen, haben die Liganden in [H-3]MDL-105,519 Rezeptorbindungsassays niedrige nanomolare Affinitäten für die Glycinbindungsstelle. Die Lipophilie der Verbindungen wurde mit drei verschiedenen Verfahren untersucht und ergab logD7,4-Werte von ungefähr 1 für cADTC1 und tADTC1 – 4, während tADTC5 mit einem logD7,4 von –1,15 eine sehr niedrige Lipophilie aufwies. Die Radiosynthesen der 18F-Liganden wurden hinsichtlich der Umsetzung der Markierungsvorläufer mit 2-[F-18]Fluorethyltosylat oder [F-18]Fluorid untersucht und optimiert. Die höchsten radiochemischen Ausbeuten von ungefähr 90% wurden, unter Verwendung von NaOH als Hilfsbase, bei der 18F-Fluorethylierung von t[F-18]ADTC4 und t[F-18]ADTC5 mit 2-[F-18]Fluorethyltosylat erzielt.ABSTRACTThe glutamergic N-methyl-D-aspartete (NMDA) receptor is a major ionotropic receptor type which mediates excitatory synaptic transmission in the mammalian central nervous system. It seems likely that the NMDA receptor is involved in a huge number of neurodegenerative disorders, such as Parkinson’s disease, Alzheimer’s disease and schizophrenia. Thus, there has been a great interest in the development of 18F-labelled NMDA receptor ligands for imaging the NMDA receptor complex by positron emission tomography.The 19F-analogues cADTC1, tADTC1 and tADTC3 - 5 and the non-fluorinated 12C-analogue tADTC2 were synthesized and their in vitro binding affinity and lipophilicity were determined. With the exception of cADTC1 and tADTC5, which have micromolar affinities, the ligands exhibit low nanomolar affinities for the glycine binding site in [H-3]MDL-105,519 assays. The lipophilicity was determined using three different methods and gave logD7,4 values of about 1 for cADTC1 and tADTC1 – 4, whilst tADTC5 showed a low lipophilicity of logD7,4 = -1.15.The radio synthesis of the 18F-ligands were examined and optimised by labelling the precursors with 2-[F-18]fluoroethyl tosylate or [F-18]fluoride. The highest radiochemical yields of about 90% were achieved by labelling the precursors of t[F-18]ADTC4 and t[F-18]ADTC5 using 2-[F-18]fluoroethyl tosylate and NaOH as base