Regulation of dissimilatory sulfur oxidation in the purple sulfur bacterium Allochromatium vinosum

In the purple sulfur bacterium Allochromatium vinosum, thiosulfate oxidation is strictly dependent on the presence of three periplasmic Sox proteins encoded by the soxBXAK and soxYZ genes. It is also well documented that proteins encoded in the dissimilatory sulfite reductase (dsr) operon, dsrABEFHCMKLJOPNRS, are essential for the oxidation of sulfur that is stored intracellularly as an obligatory intermediate during the oxidation of thiosulfate and sulfide. Until recently, detailed knowledge about the regulation of the sox genes was not available. We started to fill this gap and show that these genes are expressed on a low constitutive level in A. vinosum in the absence of reduced sulfur compounds. Thiosulfate and possibly sulfide lead to an induction of sox gene transcription. Additional translational regulation was not apparent. Regulation of soxXAK is probably performed by a two-component system consisting of a multi-sensor histidine kinase and a regulator with proposed di-guanylate cyclase activity. Previous work already provided some information about regulation of the dsr genes encoding the second important sulfur-oxidizing enzyme system in the purple sulfur bacterium. The expression of most dsr genes was found to be at a low basal level in the absence of reduced sulfur compounds and enhanced in the presence of sulfide. In the present work, we focused on the role of DsrS, a protein encoded by the last gene of the dsr locus in A. vinosum. Transcriptional and translational gene fusion experiments suggest a participation of DsrS in the post-transcriptional control of the dsr operon. Characterization of an A. vinosum ΔdsrS mutant showed that the monomeric cytoplasmic 41.1-kDa protein DsrS is important though not essential for the oxidation of sulfur stored in the intracellular sulfur globules

Vegetative and generative maintenance of self-incompatibility in six accessions of German chamomile

Self-incompatible (SI) plants are able to form ideal mother lines for hybrid crossing in hermaphroditic plants, assuring fertilization from the desired father line. To find out suitable ways to maintain SI was the aim of this study. Among 220 plants of German chamomile (Matricaria recutita (L.) Rauschert) within six accessions SI-genotypes were selected. SI was determined as staying seedless in three flower heads per plant. Initial SI-plants formed the basic paternal generation (P1) of i) maintaining the same genotypes over six months and repeating seed set analysis (P2) and of ii) conducting crossings in three versions (SI × SI, SI × NSI (not SI evaluated plants) and NSI × SI), thereby producing the F(1) population. F(1) exhibited 78% SI and P2 62% SI, indicating a higher environmental than genetic influence on SI. But heritability, calculated from the results of SI × SI crossings, showed high values (h(2) = 0.71). Within generative propagation, the influence of generation/crossing version was highly significant (p = 0.001) and the cultivar ‘Degumille’ explored the highest value of SI (86%) after SI × NSI crossings. Therefore, the intra-cultivar combination of ‘Degumille’ SI mother plants crossed with NSI father plants can be recommended as the most promising version to maintain SI in chamomile

Flowcytometric assessment of fetomaternal hemorrhage during external cephalic version at term

External cephalic version (ECV) at term is a safe procedure and reduces the incidence of cesarean sections for breech presentation. One of the known complications, however, is an ECV-related disruption of the placental barrier and a subsequent transfusion of fetal blood into maternal circulation. While the incidence of ECV-related fetomaternal hemorrhage (FMH) has been determined recently in a large trial using a manual Kleihauer-Betke test (KBT), questions remain on the amount of ECV-related FMH. KBT, which detects fetal red blood cells (RBC) on the basis of acidic resistance of fetal hemoglobin (HbF), is known to be a sensitive test, yet prone to procedural errors limiting its accuracy in quantifying FMH. In this study we investigated 50 patients for FMH before and after ECV, using a dual-color flow cytometric test kit with a lower limit of quantification of 0.05% fetal RBC in maternal peripheral blood. Three patients had a quantifiable increase of fetal RBC detected after ECV (0.06%; 0.08%; 0.1%). None of these subtle increments was predictable by ECV-related clinical parameters or translated into fetal compromise. Using a sensitive and accurate flow cytometric test method, our data provide further assurance to mothers on the safety of ECV at term

Die Rolle der Mindestreserve im Eurosystem

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Untersuchungen zum Sox-Multienzymkomplex in <em>Allochromatium vinosum</em> und zur Verwertung von Elementarschwefel in phototrophen Schwefeloxidierern

Thiosulfat wird in vielen Schwefeloxidierern durch einen Sox-Multienzymkomplex oxidiert, der in seiner Grundform aus den Proteinen SoxB, SoxXA und SoxYZ besteht. Diese katalysieren die Oxidation des Sulfonschwefels zu Sulfat [1]. In der vorliegenden Arbeit wurde die Regulation der Transkription und Translation der Gene, die für die Proteine SoxB, SoxX und SoxY in Allochromatium vinosum codieren, untersucht. Es konnte gezeigt werden, dass die Bildung der Proteine des Sox-Multienzymkomplexes in Alc. vinosum auf transkriptionaler Ebene reguliert wird. Die Expression der sox-Gene steigt bei photolithoautotrophem Wachstum mit Thiosulfat im Vergleich zu photoorganoheterotrophem Wachstum mit Malat stark an. Die Steigerung der Expression ist von der Thiosulfatkonzentration abhängig. Auch bei Wachstum mit Sulfid werden die sox-Gene stärker exprimiert, während die Expression bei Wachstum mit Sulfit der unter photoorganoheterotrophen Bedingungen entspricht. Zusätzlich wurden die mRNA-Kopienzahlen der sox-Gene in der Mutante Alc. vinosum soxB::O-Km bestimmt. In dieser Mutante ist neben soxB vermutlich auch eine stromabwärts von soxB lokalisierte putative Multisensorhybridhistidinkinase inaktiviert. Die Ergebnisse zeigten, dass dieses Protein vermutlich an der Repression von soxX in Abwesenheit von reduzierten Schwefelverbindungen beteiligt ist. Vermutlich bildet sie dabei mit einem stromabwärts gelegenen Antwortregulator ein Zwei-Komponenten-System. Neben Thiosulfat und anderen wasserlöslichen Substraten wie Sulfid, Polysulfiden und Sulfit kann von vielen phototrophen Schwefeloxidierern auch unlöslicher Elementarschwefel als Elektronendonor genutzt werden [1]. Mit Hilfe von XANES (X-Ray Absorption Near Edge Structure)-Spektroskopie konnte gezeigt werden, dass Alc. vinosum, Thiocapsa roseopersicina, Halorhodospira halophila und Halorhodospira abdelmalekii die Polymerschwefelfraktion des Elementarschwefels nutzen, während cyclo-Oktaschwefel nicht verwertet wird. Für Alc. vinosum, Tca. roseopersicina und Hlr. halophila war ein direkter Zellschwefelkontakt für die Verwertung von Elementarschwefel essentiell. Mit Hilfe der LbL-Nanoeinkapselung von Alc. vinosum-Zellen konnte zudem gezeigt werden, dass die Zellladung keine Rolle für die Anlagerung von Schwefel und Zelle spielt. Weder HPLC (High Performance Liquid Chromatography) noch XANES-Messungen an Kulturüberständen ergaben Hinweise auf lösliche Intermediate bei der Schwefelaufnahme. Durch Wachstumsversuche mit verschiedenen Inhibitoren konnte gezeigt werden, dass der Zell-Schwefelkontakt und/ oder die Aufnahme von Elementarschwefel in Alc. vinosum von Energie aus dem elektrochemischen Protonengradienten abhängig sind. Auch Thiolgruppen spielen eine Rolle bei der Etablierung des Zell-Schwefelkontaktes und/ oder der Aufnahme von Elementarschwefel. Beide Prozesse verlaufen aber ATPunabhängig. [1] Frigaard N-U & Dahl C (2009). In Advances in Microbial Physiology, Poole RK (eds.), London: Academic Press, pp. 105-200

Medicinal plants and their secondary metabolites − State of the art and trends in breeding, analytics and use in feed supplementation− with special focus on German chamomile

Plants in ecology interact with their biotic and abiotic environment. Means of interactions, and thereby crucial for the survival of the species, are secondary plant metabolites. Exploration of the plants’ metabolism in action and reaction to their environment, the formation and release of secondary plant metabolites in specific (stress) situations and their functions as attractants, defence or protection agents gives us the chance to exploit the knowledge for human purposes. The purpose of medicinal use of these metabolites turns the bearing plants into medicinal plants. Health promoting, disease preventing and other favourable effects make these plants and their extracts valuable as dietary and feed additives. This review covers some current aspects of conventional breeding, particularly of German chamomile, of phytochemical analytics and of use of medicinal plants in feed supplementation. The main three groups of functional plant metabolites terpenes, polyphenols and alkaloids are treated. Outlook in research, in challenging analytical questions and in effective product development is provided, outlining current trends in production of secondary plant metabolites and demands on the market

Macroreplantations of the upper extremity: a series of 11 patients

Introduction: Micro- or macroreplantation is classified depending on the level of amputation, distal or proximal to the wrist. This study was performed to review our experience in macroreplantation of the upper extremity with special attention to technical considerations and outcomes. Materials and methods: Between January 1990 and December 2010, 11 patients with a complete amputation of the upper extremity proximal to the wrist were referred for replantations to our department. The patients, one woman and ten men, had a mean age of 43.4±18.2years (range 19-76years). There were two elbow, two proximal forearm, four mid-forearm, and three distal forearm amputations. The mechanism of injury was crush in four, crush-avulsion in five and guillotine amputation in two patients. The Chen classification was used to assess the postoperative outcomes. The mean follow-up after macroreplantation was 7.5±6.3years (range 2-21years). Results: All but one were successfully replanted and regained limb function: Chen I in four cases (36%), Chen II in three cases (27%), Chen III in two cases (18%), and Chen IV in one patient (9%). We discuss the steps of the macroreplantation technique, the need to minimize ischemic time and the risk of ischemia reperfusion injuries. Conclusion: Thanks to improvements in technique, the indications for limb preservation after amputation can be expanded. However, because of their rarity, replantations should be performed at specialist replantation centers. Level of evidence: Level I