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Oenococcus oeni is the lactic acid bacteria most suited to carry out malolactic fermentation in wine, converting L-malic acid into L-lactic acid and carbon dioxide, thereby deacidifying wines. Indeed, wine is a harsh environment for microbial growth, partly because of its low pH. By metabolizing citrate, O. oeni maintains its homeostasis under acid conditions. Indeed, citrate consumption activates the proton motive force, helps to maintain intracellular pH, and enhances bacterial growth when it is co-metabolized with sugars. In addition, citrate metabolism is responsible for diacetyl production, an aromatic compound which bestows a buttery character to wine. However, an inhibitory effect of citrate on O. oeni growth at low pH has been highlighted in recent years. In order to understand how citrate metabolism can be linked to the acid tolerance of this bacterium, consumption of citrate was investigated in eleven O. oeni strains. In addition, malate and sugar consumptions were also monitored, as they can be impacted by citrate metabolism. This experiment highlighted the huge diversity of metabolisms between strains depending on their origin. It also showed the capacity of O. oeni to de novo metabolize certain end-products such as L-lactate and mannitol, a phenomenon never before demonstrated. It also enabled drawing hypotheses concerning the two positive effects that the slowing down of citrate metabolism could have on biomass production and malolactic fermentation occurring under low pH conditions.

Lactic acid bacteria (LAB) are Gram positive bacteria frequently used in the food industry for fermentation, mainly transformation of carbohydrates into lactic acid. In addition, these bacteria also have the capacity to metabolize citrate, an organic acid commonly found in food products. Its fermentation leads to the production of 4-carbon compounds such as diacetyl, resulting in a buttery flavor desired in dairy products. Citrate metabolism is known to have several beneficial effects on LAB physiology. Nevertheless, a controversial effect of citrate has been described on the acid tolerance of the wine bacterium Oenococcus oeni. This observation raises questions about the effect of citrate on the capacity of O. oeni to conduct malolactic fermentation in highly acidic wines. This review aims to summarize the current understanding of citrate metabolism in LAB, with a focus on the wine bacterium O. oeni. Metabolism with the related enzymes is detailed, as are the involved genes organized in cit loci. The known systems of cit locus expression regulation are also described. Finally, the beneficial effects of citrate catabolism on LAB physiology are reported and the negative impact observed in O. oeni is discussed.

Oenococcus oeni is the main lactic acid bacterium associated with malolactic fermentation (MLF) of wines. MLF plays an important role in determining the final quality of wines. Nevertheless, due to the stressful conditions inherent to wine and especially acidity, MLF may be delayed. This study aimed to explore by adaptive evolution improvements in the acid tolerance of starters but also to gain a better understanding of the mechanisms involved in adaptation toward acidity. Four independent populations of the O. oeni ATCC BAA-1163 strain were propagated (approximately 560 generations) in a temporally varying environment, consisting in a gradual pH decrease from pH 5.3 to pH 2.9. Whole genome sequence comparison of these populations revealed that more than 45% of the substituted mutations occurred in only five loci for the evolved populations. One of these five fixed mutations affects mae, the first gene of the citrate operon. When grown in an acidic medium supplemented with citrate, a significantly higher bacterial biomass was produced with the evolved populations compared to the parental strain. Furthermore, the evolved populations slowed down their citrate consumption at low pH without impacting malolactic performance.

Background: Since 2008 the Verbundweiterbildungplus programme of the Competence Centre General Practice Baden-Wuerttemberg offers continual improvement with regards to content and structure of general practice training. The programme uses the didactical concept of the CanMEDs competencies, which were developed in Canada, as a postgraduate medical training framework. Train the trainer (TTT)-programmes are an additional important element of these contentual optimisations of postgraduate training. Within this article we describe the conception and evaluation of the first TTT-workshop within the programme Verbundweiterbildungplus. Methods: The conception of the first TTT-workshop was influenced by results of a survey of general practitioner (GP) trainers and by experiences with teaching GP trainers involved in medical undergraduate teaching. A questionnaire was designed to get a self-assessment about organisational and didactic aspects oriented on the CanMEDs competencies of postgraduate medical training. In addition, the workshop was evaluated by the participants.Results: The workshop lasted 12 teaching units and included the following elements: introduction into the CanMEDs competencies, feedback training, fault management, legal and organisational aspects of post graduate training. From the 29 participating trainers 76% were male and on average 57 years old. The evaluation showed a good to very good acceptance of the workshop. Initial self-rating showed the need of improving in the fields of determining learning objectives, providing formative feedback and incorporation of a trainee. Most trainers rated themselves as very good in procure CanMEDs competencies with the exclusion of the competencies "Manager" and "Scholar". Conclusion: A TTT-programme is an important method to improve GP training which has not been used in Germany so far. Such a GP TTT-programme should highlight especially training in providing feedback and teaching in management aspects. Results of thi, Zielsetzung: Das Programm Verbundweiterbildungplus des Kompetenzzentrums Allgemeinmedizin Baden Württemberg bietet seit 2008 strukturelle und inhaltliche Optimierungen für die Weiterbildung Allgemeinmedizin an. Das Programm orientiert sich am didaktischen Konzept der in Kanada entwickelten Kompetenzfelder der CanMEDs. Schulungen für Weiterbildungsbefugte, sogenannte "Train the Trainer (TTT) -Programme", sind ein ergänzendes wesentliches Element einer inhaltlichen Optimierung der Weiterbildung. Der vorliegende Artikel beschreibt die Konzeption und Evaluation des ersten TTT-Workshops im Rahmen der Verbundweiterbildungplus. Methodik: Für die Konzeption des TTT-Workshops wurden Ergebnisse einer Umfrage bei Weiterbildungsbefugten sowie Erfahrungen aus Schulungen allgemeinmedizinischer Lehrpraxen herangezogen. Ferner wurde ein Fragebogen konzipiert, mit dem die Vorgehensweisen der Weiterbilder sowie deren Selbsteinschätzung, bestimmte Kompetenzen (orientiert am CanMEDs Modell) vermitteln zu können, abgefragt wurden. Ergänzend wurde die Veranstaltung evaluiert.Ergebnisse: Der Workshop war mit 12 Unterrichtseinheiten konzipiert und enthielt folgende Elemente: Einführung in die Kompetenzfelder der CanMEDs, Feedbacktraining, Fehlermanagement, rechtliche und organisatorische Aspekte der Weiterbildung. Es nahmen 29 Weiterbildungsbefugte (im Mittel 57 Jahre, 76% männlich) teil. Die Evaluationsergebnisse zeigen eine gute bis sehr gute Akzeptanz der Veranstaltung. Die eingangs durchgeführte Fragebogenerhebung zu den aktuellen Vorgehensweisen der Weiterbilder zeigt Optimierungsbedarf bei der Vereinbarung von Lernzielen, Feedbackgabe und der strukturierten Einarbeitung eines Arztes in Weiterbildung. Der überwiegende Teil der Weiterbildungsbefugten schätzt sich insgesamt als sehr gut in der Vermittlung von CanMEDs Kompetenzen ein, lediglich bei den Kompetenzfeldern "Praxismanagement" und "Lehren und Lernen" ist die Selbsteinschätzung etwas schwächer. Schlussfolgerungen: Für die Allge

Background: Ever since the last amendment to the German Medical Licensing Act took effect in 2002, medical students may complete four months of the Practical Year (PY) in general practices. Formative feedback between the teaching general practitioner (GP) and the PY student is a key element in creating a learning environment. GPs involved in teaching therefore need further education in giving feedback.Methods: A 4-hour feedback training session for GPs involved in teaching which used standardized patients and students was developed and tested in a pilot study. In role plays, GPs experienced feedback situations. Using an evaluation questionnaire, changes in self-perceived feedback skills were assessed (familiarity of feedback rules, preparation for giving feedback to PY students, possibilities to improve communication skills in doctor-patient situations).Results: Sixteen GPs who were involved or interested in PY teaching participated in the feedback training program. Afterwards, participants said they felt more comfortable in giving formative feedback and more assured in their communication skills. The confidence in their own feedback improved, especially by taking the student's part in the role plays. An exercise between a standardized patient and a standardized stubborn student was a challenge, but proved to be extremely useful.Conclusion: The opinions of the participating GPs to the feedback training underscore its importance. Therefore, we recommend integrating such a feedback training program into the education of GPs involved in teaching., Hintergrund: Seit der letzten Novelle der Approbationsordnung 2002 besteht die Möglichkeit, ein Tertial des Praktischen Jahres (PJ) in Hausarztpraxen zu absolvieren. Konstruktives Feedback zwischen Arzt und PJ-Studenten ist dabei ein zentrales Element in der Gestaltung des Lernumfeldes in der Arztpraxis. Es bedarf dahingehend einer Ausbildung der in die Lehre involvierten niedergelassenen Lehrärzte.Methoden: Es wurde ein vierstündiges Feedbacktrainingsprogramm mit standardisierten Rollenspielen für Lehrärzte in der Allgemeinmedizin entwickelt und in einem Pilotversuch umgesetzt. Mittels eines Evaluationsbogens wurde eine Selbsteinschätzung der Teilnehmer im Feedback durch einen Vorher-Nachher-Vergleich erfasst (Bekanntheit von Feedbackregeln, Vorbereitung auf Gesprächssituationen mit PJ-Studierenden, Verbesserungsmöglichkeiten der kommunikativen Fähigkeiten im Arzt-Patienten-Gespräch).Ergebnisse: 16 allgemeinmedizinisch tätige Ärztinnen und Ärzte, in PJ involviert bzw. daran interessiert, nahmen an dem Feedbacktraining teil. Die Teilnehmer waren ihrer eigenen Einschätzung folgend nach dem Training vertrauter mit formativem Feedback, ebenso im Umgang mit den eigenen kommunikativen Fertigkeiten. Das Selbstvertrauen in das eigene Feedback verbesserte sich vor allem durch die Selbsterfahrung in der studentischen Rolle. Die Kommunikationsübung zwischen einem Standardisierten Patienten und einem uneinsichtigen Standardisierten Studenten wurde als besondere Herausforderung, aber auch als sehr nützlich im Rahmen des Trainings angesehen.Schlussfolgerung: Die Rückmeldungen der allgemeinmedizinisch tätigen Teilnehmer zum Feedbacktraining bestätigen unseren Ansatz. Wir empfehlen daher die Integration eines solchen Feedbacktrainings in die Ausbildung von Lehrärzten im Fach Allgemeinmedizin.