Regulation of mtl operon promoter of Bacillus subtilis: requirements of its use in expression vectors

Several vector systems have been developed to express any gene desired to be studied in Bacillus subtilis. Among them, the transcriptionally regulated promoters involved in carbohydrate utilization are a research priority. Expression systems based on Bacillus promoters for xylose, maltose, and mannose utilization, as well as on the heterologous E. coli lactose promoter, have been successfully constructed. The promoter of the mtlAFD operon for utilization of mannitol is another promising candidate for its use in expression vectors. In this study, we investigated the regulation of the mtl genes in order to identify the elements needed to construct a strong mannitol inducible expression system in B. subtilis. Regulation of the promoters of Bacillus subtilis mtlAFD operon (PmtlA) and mtlR (PmtlR) encoding the activator were investigated by fusion to lacZ. Identification of the PmtlA and PmtlR transcription start sites revealed the sigma A like promoter structures. Also, the operator of PmtlA was determined by shortening, nucleotide exchange, and alignment of PmtlA and PmtlR operator regions. Deletion of the mannitol-specific PTS genes (mtlAF) resulted in PmtlA constitutive expression demonstrating the inhibitory effect of EIICBMtl and EIIAMtl on MtlR in the absence of mannitol. Disruption of mtlD made the cells sensitive to mannitol and glucitol. Both PmtlA and PmtlR were influenced by carbon catabolite repression (CCR). However, a CcpA deficient mutant showed only a slight reduction in PmtlR catabolite repression. Similarly, using PgroE as a constitutive promoter, putative cre sites of PmtlA and PmtlR slightly reduced the promoter activity in the presence of glucose. In contrast, glucose repression of PmtlA and PmtlR was completely abolished in a ptsG deletion mutant and significantly reduced in a MtlR (H342D) mutant

L’intention de croissance des PME marocaines en contexte de crise

SMEs are the cornerstone of the Moroccan economy. They recruit, invest, and contribute strongly to economic growth. Indeed, the latter remains dependent on their growth and development. Nevertheless, contrary to what many people think, growth is not a common goal among SME managers. Some want to grow their businesses, while others are satisfied with the status quo. This research develops an in-depth analysis of the growth intention of Moroccan SMEs, while taking into account the crisis context in which it was conducted. In this sense, the study has two objectives: to understand through the eyes and perceptions of managers the impact that the crisis may have had on their business, and to understand their intention to grow during this context. After a literature review highlighting the role of the manager within the SME, and the results of the work on growth intention, we conducted, through a qualitative approach, four interviews with four Moroccan SME managers, located in Marrakech. The interviews, conducted between month 3 and month 4 of 2022, were transcribed according to the sociological method, and then analyzed by hand, through a horizontal and vertical analysis. Following this analysis, the results generated demonstrate that growth is a polyphonic concept, and that the intention to grow is protean: four modalities of the intention to grow have emerged. Strong growth intention, moderate growth intention, pending growth intention, and no growth intention. The results of this research contribute to the understanding of the perceptions of SME managers, which in return, would allow public authorities to put in place more adapted and therefore more useful support mechanisms in order to encourage them to grow.     JEL Classification: G01, L25, L1 Paper type: Empirical researchLes PME constituent la pierre angulaire de l’économie marocaine. Elles recrutent, et investissent, et contribuent fortement dans la croissance économique. En effet, ce dernier reste tributaire de leur croissance et développement. Néanmoins, contrairement à ce que pensent beaucoup de gens, la croissance n’est pas une finalité commune entre dirigeants des PME. Certains désirent développer leurs entreprises, en revanche, d’autres sont satisfaits du statu quo. Cette recherche développe une analyse en profondeur de l’intention de croissance des PME marocaines, tout en prenant en compte le contexte de crise où elle a été menée. Dans ce sens, l’étude présente un double objectif : Comprendre à travers l’œil et perception des dirigeants l’impact qu’a pu avoir la crise sur leur activité, et appréhender leur intention de croissance durant ce contexte. Après une revue de littérature mettant la lumière sur le rôle du dirigeant au sein de la PME, ainsi que sur les résultats des travaux portant sur l’intention de croissance, nous avons mené, à travers une approche qualitative, quatre entretiens auprès de quatre dirigeants de PME marocaines, situées à Marrakech. Les entretiens conduits entre le mois 3 et le mois 4 de l’année 2022, ont été retranscrits selon la méthode sociologique, puis analysée à la main, à travers une analyse horizontale et verticale. À la suite de cette analyse, les résultats générés démontrent que la croissance est un concept polyphonique, et que l’intention de croissance est protéiforme : quatre modalités de l’intention de croissance ont émergé. L’intention de croissance forte, l’intention de croissance modérée, l’intention de croissance en suspens, et l’intention de non-croissance. Les résultats de cette recherche contribuent dans la compréhension des perceptions des dirigeants des PME, ce qui par conséquent, permettrait aux pouvoirs publics de mettre en place des dispositifs d’appui plus adaptés et donc plus utiles, afin de les encourager à se développer.     Classification JEL : G01, L25, L1 Type de l’article : Recherche appliqué

Deletion of Rap-phosphatases for quorum sensing control in Bacillus and its effect on surfactin production

The complex regulatory network in Bacillus, known as quorum sensing, offers many opportunities to modify bacterial gene expression and hence to control bioprocesses. One target regulated by this mechanism is the activity of the PsrfA promoter, which is engaged in the formation of lipopeptide surfactin. It was hypothesised that deletion of rapC, rapF and rapH, encoding for prominent Rap-phosphatases known to affect PsrfA activity, would enhance surfactin production. Therefore, these genes were deleted in a sfp + derivative of B. subtilis 168 with subsequent evaluation of quantitative data. Up to the maximum product formation of the reference strain B. subtilis KM1016 after 16 h of cultivation, the titers of the rap deletion mutants did not exceed the reference. However, an increase in both product yield per biomass Y P/X and specific surfactin productivity q surfactin was observed, without any considerable effect on the ComX activity. By extending the cultivation time, a 2.7-fold increase in surfactin titer was observed after 24 h for strain CT10 (ΔrapC) and a 2.5-fold increase for CT11 (ΔrapF) compared to the reference strain KM1016. In addition, Y P/X was again increased for strains CT10 and CT11, with values of 1.33 g/g and 1.13 g/g, respectively. Interestingly, the effect on surfactin titer in strain CT12 (ΔrapH) was not as distinct, although it achieved the highest promoter activity (PsrfA-lacZ). The data presented support the possibility of involving the quorum sensing system of Bacillus in bioprocess control as shown here on the example of lipopeptide production.</p

Composition of liquid ion exchangers

SIGLEAvailable from British Library Document Supply Centre- DSC:D31907/80 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

La mémoire de la guerre dans le roman contemporain de langue française : discontinuité et dislocation narratives dans les œuvres d’Henry Bauchau, d’Andrée Chedid et d’Anna Moï

Texte intégral accessible uniquement aux membres de l'Université de Lorraine jusqu'au 01 septembre 2025The present research considers some aspects of dislocated writing under the influence of the memory of war in the contemporary French-language novel. The study favours a narratological approach in three novels: Anna Moï's Riz noir, Andrée Chedid's Le Message and Henry Bauchau's Le Boulevard périphérique. The choice of this corpus gives an overview of three different wars that occurred in the world. However, our study focuses on the tragic impact of war in general on three novels that, albeit being from the extreme-contemporary and coming from different nations, remind the twentieth century. This study aims to analyze how the authors succeed in transmitting the trauma of war, which raises the issues of discontinued and dislocated writing llustrating the hesitations or even the obsessions of an intermittent memory. In the first part, the thesis will focus mainly on the socio-historical changes of the turn of the 21st century and on the perception of a fragmented world, especially in the novel. The second and third parts, mostly emphasizing on narratological aspects, analyze the considered novels as memorial writings and examine the phenomena of a discontinued temporality as well as dislocated space in the composition of the three novels. The fourth part will present an overview of the composition of the novels and will examine the unifying processes ensuring the coherence of the novel. It will focus on the world of values present in the three studied novels evoking the axiological aspects of the novels and their ethical dimension towards war in order to give the reader the idea of a coherent reconstruction of a tragic History.Ce travail envisage les enjeux d'une narration discontinue et disloquée sous l'influence de la mémoire de la guerre dans le roman contemporain de langue française. Elle privilégie une approche narratologique pour l’analyse de trois romans : Le Message d’Andrée Chedid (2000), Riz noir d’Anna Moï (2004), Le Boulevard périphérique de Henry Bauchau (2008). Le choix du corpus donne un aperçu général sur trois guerres différentes dans le monde ; cependant, notre étude s’intéressera plutôt à l’impact tragique de la guerre, en général, sur trois œuvres qui, tout en relevant de l’extrême-contemporain et venant de nations différentes, se souviennent du XXe siècle. Ici, l’enjeu de l’analyse est de montrer comment l'auteur réussit à transmettre le traumatisme de la guerre, ce qui soulève, dès lors, des enjeux de la narration discontinue et disloquée, qui suit les hésitations, voir les obsessions d'une mémoire intermittente. Dans une première partie, la thèse se concentrera sur les mutations socio-historiques du tournant du XXIe siècle et sur la perception d’un monde éclaté, spécialement dans le domaine romanesque. La deuxième et la troisième partie, essentiellement narratologiques, étudieront les romans considérés en tant qu’écritures mémorielles et y examineront les phénomènes de dislocation narrative dans l’organisation du temps et de l’espace des récits. La quatrième partie, présentera une vue d'ensemble sur la composition des romans et examinera les procédures d’unification relative assurant la cohérence romanesque. Nous nous intéresserons, ici, aux univers de valeurs inscrits dans les trois romans à l’étude ; ce qui nous amènera à évoquer leurs aspects axiologiques et leur dimension éthique face à la guerre, destinés à donner au lecteur l'idée d'une recomposition d'une Histoire tragique

Memory of war in contemporary French language novel : narrative discontinuity and dislocation in the novel of Henry Bauchau, Andrée Chedid and Anna Moï

Ce travail envisage les enjeux d'une narration discontinue et disloquée sous l'influence de la mémoire de la guerre dans le roman contemporain de langue française. Elle privilégie une approche narratologique pour l’analyse de trois romans : Le Message d’Andrée Chedid (2000), Riz noir d’Anna Moï (2004), Le Boulevard périphérique de Henry Bauchau (2008). Le choix du corpus donne un aperçu général sur trois guerres différentes dans le monde ; cependant, notre étude s’intéressera plutôt à l’impact tragique de la guerre, en général, sur trois œuvres qui, tout en relevant de l’extrême-contemporain et venant de nations différentes, se souviennent du XXe siècle. Ici, l’enjeu de l’analyse est de montrer comment l'auteur réussit à transmettre le traumatisme de la guerre, ce qui soulève, dès lors, des enjeux de la narration discontinue et disloquée, qui suit les hésitations, voir les obsessions d'une mémoire intermittente. Dans une première partie, la thèse se concentrera sur les mutations socio-historiques du tournant du XXIe siècle et sur la perception d’un monde éclaté, spécialement dans le domaine romanesque. La deuxième et la troisième partie, essentiellement narratologiques, étudieront les romans considérés en tant qu’écritures mémorielles et y examineront les phénomènes de dislocation narrative dans l’organisation du temps et de l’espace des récits. La quatrième partie, présentera une vue d'ensemble sur la composition des romans et examinera les procédures d’unification relative assurant la cohérence romanesque. Nous nous intéresserons, ici, aux univers de valeurs inscrits dans les trois romans à l’étude ; ce qui nous amènera à évoquer leurs aspects axiologiques et leur dimension éthique face à la guerre, destinés à donner au lecteur l'idée d'une recomposition d'une Histoire tragique.The present research considers some aspects of dislocated writing under the influence of the memory of war in the contemporary French-language novel. The study favours a narratological approach in three novels: Anna Moï's Riz noir, Andrée Chedid's Le Message and Henry Bauchau's Le Boulevard périphérique. The choice of this corpus gives an overview of three different wars that occurred in the world. However, our study focuses on the tragic impact of war in general on three novels that, albeit being from the extreme-contemporary and coming from different nations, remind the twentieth century. This study aims to analyze how the authors succeed in transmitting the trauma of war, which raises the issues of discontinued and dislocated writing llustrating the hesitations or even the obsessions of an intermittent memory. In the first part, the thesis will focus mainly on the socio-historical changes of the turn of the 21st century and on the perception of a fragmented world, especially in the novel. The second and third parts, mostly emphasizing on narratological aspects, analyze the considered novels as memorial writings and examine the phenomena of a discontinued temporality as well as dislocated space in the composition of the three novels. The fourth part will present an overview of the composition of the novels and will examine the unifying processes ensuring the coherence of the novel. It will focus on the world of values present in the three studied novels evoking the axiological aspects of the novels and their ethical dimension towards war in order to give the reader the idea of a coherent reconstruction of a tragic History

Regulation der Mannitol-Abbaugene in Bacillus subtilis

Bacillus subtilis takes up mannitol by a phosphoenolpyruvate-dependent phosphotransferase system (PTS). The mannitol utilization system is encoded by the mtlAFD operon consisting of mtlA (encoding membrane-bound EIICBMtl), mtlF (encoding phosphocarrier EIIAMtl), and mtlD (encoding mannitol 1-phosphate dehydrogenase). This operon is activated by MtlR whose coding gene is located approx. 14.4 kb downstream of the operon. The regulation of the mannitol utilization genes in B. subtilis was studied by fusion of the promoters of mtlAFD (PmtlA) and mtlR (PmtlR) to lacZ as a reporter gene. Both the PmtlA and PmtlR were inducible by mannitol and glucitol, while glucose reduced their activities. The promoter strength of PmtlA was about 4.5-fold higher than that of PmtlR. Identification of the transcription start sites of PmtlA and PmtlR revealed that both of these promoters contain a sigma A-type promoter structure. The promoter -35 and -10 boxes in PmtlA were TTGTAT and TAACAT and in PmtlR TTGATT and TATATT, respectively. Catabolite responsive elements (cre) were detected in the sequences of PmtlA and PmtlR overlapping the -10 boxes. Shortening the mRNA 5’untranslated region (5’UTR) increased the PmtlA activity, whereas PmtlR activity was decreased by shortening of its mRNA 5’UTR. Alignment of the -35 upstream sequences of PmtlA and PmtlR revealed the putative MtlR binding site. This sequence comprised a similar incomplete inverted repeat in both the PmtlA and PmtlR sequences (TTGNCACAN4TGTGNCAA). This sequence was encompassed by two 11 bp distal and proximal flanking sequences. Construction of PmtlA-PlicB hybrid promoters and shortening of the 5’-end of PmtlA indicated the probable boundaries of putative MtlR binding site in PmtlA. Increasing the distance between the putative MtlR binding site and -35 box lowered the PmtlA maximal activity, although PmtlA remained inducible by mannitol. PmtlA became inactive by disruption of the TTGNCACAN4TGTGNCAA sequence. In contrast, manipulation of the distal and proximal flanking sequences only reduced the maximal activity of PmtlA, whereas PmtlA remained highly inducible. These flanking sequences contained AT-rich repeats similar to the consensus sequence of alpha CTD binding sites. Regulation of PmtlA and PmtlR was investigated by deletion of mtlAF, mtlF, mtlD, and mtlR. Deletion of the mtlAF genes rendered PmtlA and PmtlR constitutive showing the inhibitory effect of EIICBMtl and EIIAMtl (PTS transporter components) on MtlR in the absence of mannitol. The constitutive activity of PmtlA was increased by the deletion of mtlF. In contrast, the deletion of mtlAFD showed a significant reduction in the PmtlA constitutive activity. Disruption of mtlD made B. subtilis sensitive to mannitol in a way that addition of mannitol or glucitol to the bacterial culture ended in cell lysis. Besides, PmtlA and PmtlR were similarly induced by glucitol and mannitol in a mtlD::erm mutant. Also, deletion of mtlR rendered PmtlA and PmtlR uninducible by mannitol or glucitol. In contrast, deletion of the glucitol utilization genes had no influence on the inducibility of PmtlA or PmtlR by glucitol. The PmtlA activity was drastically reduced in ptsH-H15A (HPr-H15A) mutant similar to the delta mtlR mutant. The mutation of histidine 289 in the PRDI domain of MtlR to alanine reduced the activity of PmtlA, whereas the PmtlA activity in the mtlR H230A mutant was almost similar to wild type. In contrast, mutation of the PRDII domain of MtlR to H342D mainly relieved PmtlA from glucose repression. Moreover, MtlR double mutant H342D C419A which was produced in E. coli was shown to be active in vitro. These results represent the positive regulation of MtlR via phosphorylation of the PRDII domain by HPr(H15~P). Also, dephosphorylation of the domains EIIBGat- and EIIAMtl-like of MtlR by EIIAMtl and EIICBMtl transporter components causes activation. The PmtlA activity was repressed in the presence of glucose and fructose, while sucrose and mannose had no influence on the PmtlA activity. Therefore, catabolite repression of PmtlA and PmtlR were studied by CcpA-dependent carbon catabolite repression mutants, such as ptsH-S46A, delta crh, delta hprK, and delta ccpA. Induction of PmtlA and PmtlR in these mutants did not result in a complete loss of catabolite repression. Therefore, the catabolite responsive elements (cre sites) of PmtlA and PmtlR were investigated. Using a constitutive promoter, PgroE, it was shown that the cre sites of PmtlA and PmtlR were weakly functional. In contrast, deletion of the glucose PTS transporter, encoded by ptsG, resulted in a complete loss of glucose repression in PmtlA and PmtlR. Thus, the main glucose repression of mannitol PTS function at the posttranslational level in a HPr-mediated manner via MtlR-H342 and at transcriptional level by CcpA-dependent carbon catabolite repression.Bacillus subtilis nimmt Mannitol mit Hilfe eines Phosphoenolpyruvat-abhängigem Phosphotransferasesystems auf. Dieses wird durch das mtlAFD-Operon codiert, welches aus mtlA (codiert das Membran-gebundene EIICBMtl), mtlF (codiert das Phosphorylgruppen-übertragende EIIAMtl) und mtlD (codiert die Mannitol-1-phosphat-Dehydrogenase) besteht. Das Operon wird durch MtlR aktiviert, dessen Gen ca. 14,4 kb stromabwärts des Operons lokalisiert ist. Die Regulation der Gene für die Mannitol-Verwertung in B. subtilis wurde mit Hilfe des Reportergens lacZ untersucht, welches an die Promotoren vom mtlAFD (PmtlA) sowie mtlR (PmtlR) fusioniert wurde. Sowohl PmtlA als auch PmtlR wurden durch Mannitol und Glucitol induziert, während Glucose die Promotoraktivitäten reprimierte. Im Vergleich zu PmtlR zeigte PmtlA eine ca. 4,5-fach höhere Promotorstärke. Die Analyse der Transkriptionsinitiations-Sequenzen durch Transkriptionsstartbestimmung von PmtlA und PmtlR ergab, dass es sich um Sigma A-abhängige Promotoren handelt. Die -35 und -10 Promotorsequenzen von PmtlA und PmtlR wurden als TTGTAT und TAACAT bzw. TTGATT und TATATT identifiziert. In beiden Promotoren wurden cre- Sequenzen (catabolite responsive element) gefunden, welche mit den -10 Regionen überlappen. Eine Verkürzung der 5‘-untranslatierten Region (5’UTR) von PmtlA erhöhte dessen Aktivität, wohingegen die Aktivität von PmtlR durch die Verkürzung der 5’UTR reduziert wurde. Durch Sequenzalignment der stromaufwärts von PmtlA und PmtlR gelegenen Sequenzen konnte die mutmaßliche MtlR-Bindestelle identifiziert werden. Diese Bindestelle ist in beiden Sequenzen durch eine unvollständig ausgeprägte, invertierte Wiederholungssequenz (TTGNCACAN4TGTGNCAA) charakterisiert, welche ihrerseits von jeweils zwei 11 bp langen Sequenzen flankiert wird. Die Regulation von PmtlA und PmtlR wurde mit Hilfe von mtlAF-, mtlF-, mtlD- und mtlR-Deletionen in B. subtilis untersucht. Die Deletion von mtlAF führte zu einer konstitutiven Aktivität von PmtlA und PmtlR, wodurch der inhibitorische Effekt von EIICBMtl und EIIAMtl (Untereinheiten des PTS-Transporters) auf MtlR bei Abwesenheit von Mannitol gezeigt werden konnte. Die konstitutive Aktivität von PmtlA wurde durch die Deletion von mtlF noch verstärkt. Im Gegensatz dazu verursachte die Deletion von mtlAFD eine signifikante Reduktion der konstitutiven Aktivität von PmtlA. Die Mutation von mtlD resultierte in einer Sensitivität von B. subtilis gegenüber Mannitol und Glucitol. Kultivierung in Gegenwart dieser Zucker führte zu einer Lyse der Zellen. In der mtlD::erm Mutante wurden PmtlA und PmtlR durch Glucitol und Mannitol gleichermaßen induziert. Ferner führte die Deletion von mtlR zu einer Uninduzierbarkeit von PmtlA und PmtlR mit Mannitol und Glucitol, wohingegen die Deletion der Gene für die Glucitol-Verwertung keinen Einfluss auf die Induzierbarkeit von PmtlA und PmtlR mit Glucitol hatte. Wie auch in der Delta mtlR Mutante war die Aktivität von PmtlA in der ptsH-H15A (HPr-H15A) Mutante drastisch reduziert. Die Mutation des Histidin 289 in der PRDI-Domäne von MtlR zu einem Alanin reduzierte die Aktivität von PmtlA, während die Aktivität von PmtlA in der mtlR-H230A-Mutante ähnlich wie die des Wildtyps war. Im Gegensatz dazu führte die Mutation H342D der PRDII-Domäne von MtlR zu einer verminderten Glucose-Repression von PmtlA. Eine MtlR Doppelmutante H342D C419A wurde in E. coli produziert und ihre Aktivität in einem Gelmobilityshiftassay in vitro bestätigt. Diese Ergebnisse zeigen, dass MtlR einer, durch die Phosphorylierung der PRDII-Domäne durch HPr(H15~P) stattfindenden, positiven Regulation unterliegt. Ferner kann eine Aktivierung von MtlR durch eine Dephosphorylierung der EIIBGat- und EIIAMtl-ähnlichen Domänen durch die EIIAMtl und EIICBMtl Transporter-Untereinheiten erreicht werden. Glucose und Fructose reprimieren die Aktivität von PmtlA wohingegen Saccharose und Mannose keinen Einfluss auf die PmtlA-Aktivität haben. Daher wurde die Kohlenstoff-Katabolit-Repression von PmtlA und PmtlR in CcpA-abhängigen Mutanten, wie ptsH-S46A, Delta crh, Delta hprK und Delta ccpA, untersucht. Da eine Induktion von PmtlA und PmtlR in den Mutanten nicht zu einem vollständigen Verlust der Katabolit-Repression führte, wurden die cre-Sequenzen (catabolite responsive element) der beiden Promotoren untersucht. Mit Hilfe des konstitutiven Promotors PgroE wurde gezeigt, dass die cre-Sequenzen von PmtlA und PmtlR nur schwach funktionsfähig waren. Im Gegensatz dazu führte die Deletion des Glucose-PTS-Transporters, welcher von ptsG codiert wird, zu einem vollständigen Verlust der Glucose-Repression von PmtlA und PmtlR. Folglich wird die Repression des Mannitol-PTS durch Glucose hauptsächlich posttranslational durch HPr via MtlR-H342 und auf transkriptionaler Ebene durch eine CcpA-abhängige Kohlenstoff-Katabolit-Repression vermittelt

Recension de : Bédé Damien et Coulibaly Moussa (éds.), L’Écriture fragmentaire dans les récits de productions africaines contemporaines, Paris, L’Harmattan, « Espaces littéraires », 2015, 226 p.

International audienc

Recension de : Bédé Damien et Coulibaly Moussa (éds.), L’Écriture fragmentaire dans les récits de productions africaines contemporaines, Paris, L’Harmattan, « Espaces littéraires », 2015, 226 p.

International audienc