Search results for: Tamara Hoffmann

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The many faces of the unusual biofilm activator RemA

Erhard Bremer, Tamara Hoffmann, Felix Dempwolff, Patricia Bedrunka, more

BioEssays > 44 > 5 > n/a - n/a

Biofilms can be viewed as tissue‐like structures in which microorganisms are organized in a spatial and functional sophisticated manner. Biofilm formation requires the orchestration of a highly integrated network of regulatory proteins to establish cell differentiation and production of a complex extracellular matrix. Here, we discuss the role of the essential Bacillus subtilis biofilm activator RemA...

article

Cellular adaptation of Clostridioides difficile to high salinity encompasses a compatible solute‐responsive change in cell morphology

Annika‐Marisa Michel, José Manuel Borrero‐de Acuña, Gabriella Molinari, Can Murat Ünal, more

Environmental Microbiology > 24 > 3 > 1499 - 1517

Infections by the pathogenic gut bacterium Clostridioides difficile cause severe diarrhoeas up to a toxic megacolon and are currently among the major causes of lethal bacterial infections. Successful bacterial propagation in the gut is strongly associated with the adaptation to changing nutrition‐caused environmental conditions; e.g. environmental salt stresses. Concentrations of 350 mM NaCl, the...

article

Impact of high salinity and the compatible solute glycine betaine on gene expression of Bacillus subtilis

Hermann Rath, Praveen K. Sappa, Tamara Hoffmann, Manuela Gesell Salazar, more

Environmental Microbiology > 22 > 8 > 3266 - 3286

The Gram‐positive bacterium Bacillus subtilis is frequently exposed to hyperosmotic conditions. In addition to the induction of genes involved in the accumulation of compatible solutes, high salinity exerts widespread effects on B. subtilis physiology, including changes in cell wall metabolism, induction of an iron limitation response, reduced motility and suppression of sporulation. We performed...

article

Arsenobetaine: an ecophysiologically important organoarsenical confers cytoprotection against osmotic stress and growth temperature extremes

Tamara Hoffmann, Bianca Warmbold, Sander H. J. Smits, Britta Tschapek, more

Environmental Microbiology > 20 > 1 > 305 - 323

Arsenic, a highly cytotoxic and cancerogenic metalloid, is brought into the biosphere through geochemical sources and anthropogenic activities. A global biogeochemical arsenic biotransformation cycle exists in which inorganic arsenic species are transformed into organoarsenicals, which are subsequently mineralized again into inorganic arsenic compounds. Microorganisms contribute to this biotransformation...

article

Transcriptional regulation of ectoine catabolism in response to multiple metabolic and environmental cues

Annina Schulz, Lucas Hermann, Sven‐Andreas Freibert, Tobias Bönig, more

Environmental Microbiology > 19 > 11 > 4599 - 4619

Ectoine and hydroxyectoine are effective microbial osmostress protectants, but can also serve as versatile nutrients for bacteria. We have studied the genetic regulation of ectoine and hydroxyectoine import and catabolism in the marine Roseobacter species Ruegeria pomeroyi and identified three transcriptional regulators involved in these processes: the GabR/MocR‐type repressor EnuR, the feast and...

article

Synthesis of the compatible solute proline by Bacillus subtilis: point mutations rendering the osmotically controlled proHJ promoter hyperactive

Tamara Hoffmann, Monika Bleisteiner, Praveen Kumar Sappa, Leif Steil, more

Environmental Microbiology > 19 > 9 > 3700 - 3720

The ProJ and ProH enzymes of Bacillus subtilis catalyse together with ProA (ProJ‐ProA‐ProH), osmostress‐adaptive synthesis of the compatible solute proline. The proA‐encoded gamma‐glutamyl phosphate reductase is also used for anabolic proline synthesis (ProB‐ProA‐ProI). Transcription of the proHJ operon is osmotically inducible whereas that of the proBA operon is not. Targeted and quantitative proteome...

article

From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

Laura Teichmann, Chiliang Chen, Tamara Hoffmann, Sander H.J. Smits, more

Molecular Microbiology > 104 > 5 > 761 - 780

The ABC‐transporters OpuB and OpuC from Bacillus subtilis function as osmoprotectant import systems. Their structural genes have most likely evolved through a duplication event but the two transporters are remarkably different in their substrate profile. OpuB possesses narrow substrate specificity, while OpuC is promiscuous. We assessed the functionality of hybrids between these two ABC‐transporters...

article

Feeding on compatible solutes: A substrate‐induced pathway for uptake and catabolism of ectoines and its genetic control by EnuR

Annina Schulz, Nadine Stöveken, Ina M. Binzen, Tamara Hoffmann, more

Environmental Microbiology > 19 > 3 > 926 - 946

Ectoine and 5‐hydroxyectoine are widely synthesized microbial osmostress protectants. They are also versatile nutrients but their catabolism and the genetic regulation of the corresponding genes are incompletely understood. Using the marine bacterium Ruegeria pomeroyi DSS‐3, we investigated the utilization of ectoines and propose a seven steps comprising catabolic route that entails an initial conversion...

chapter

Physiological and Molecular Responses of Bacillus subtilis to Hypertonicity: Utilization of Evolutionarily Conserved Adaptation Strategies

Gudrun Holtmann, Clara D. Boiangiu, Jeanette Brill, Tamara Hoffmann, more

Halophilic Microorganisms > 115-134

Variations in the supply of water and the concomitant changes in salinity and osmolality are among the most significant environmental parameters affecting the survival and growth of microorganisms (Galinski and Trüper 1994; Csonka and Epstein 1996; Wood 1999; Bremer and Krämer 2000). Microorganisms can colonize a wide variety of ecological niches with a considerable spectrum of salinitiFs and osmotic...

article

Abiotic stress protection by ecologically abundant dimethylsulfoniopropionate and its natural and synthetic derivatives: insights from Bacillus subtilis

Sebastian Broy, Chiliang Chen, Tamara Hoffmann, Nelson L. Brock, more

Environmental Microbiology > 17 > 7 > 2362 - 2378

Dimethylsulfoniopropionate (DMSP) is an abundant osmolyte and anti‐stress compound produced primarily in marine ecosystems. After its release into the environment, microorganisms can exploit DMSP as a source of sulfur and carbon, or accumulate it as an osmoprotectant. However, import systems for this ecophysiologically important compatible solute, and its stress‐protective properties for microorganisms...

article

Adaptation of Bacillus subtilis carbon core metabolism to simultaneous nutrient limitation and osmotic challenge: a multi‐omics perspective

Michael Kohlstedt, Praveen K. Sappa, Hanna Meyer, Sandra Maaß, more

Environmental Microbiology > 16 > 6 > 1898 - 1917

The Gram‐positive bacterium Bacillus subtilis encounters nutrient limitations and osmotic stress in its natural soil ecosystem. To ensure survival and sustain growth, highly integrated adaptive responses are required. Here, we investigated the system‐wide response of B. subtilis to different, simultaneously imposed stresses. To address the anticipated complexity of the cellular response networks,...

article

Mutational activation of the RocR activator and of a cryptic rocDEF promoter bypass loss of the initial steps of proline biosynthesis in Bacillus subtilis

Adrienne Zaprasis, Tamara Hoffmann, Guido Wünsche, Lope A. Flórez, more

Environmental Microbiology > 16 > 3 > 701 - 717

The gamma‐glutamyl‐phosphate reductase (ProA) interlinks both the anabolic and osmostress adaptive proline biosynthetic routes of Bacillus subtilis. Because no paralogous protein to ProA exists in this microorganism, proA mutants should exhibit a tight proline auxotrophic growth phenotype. Contrary to expectations, proA mutants formed microcolonies on agar plates lacking proline and faster growing...

article

Prolin — vielfältig wie ein Schweizer Taschenmesser

Tamara Hoffmann, Erhard Bremer

BIOspektrum > 2013 > 19 > 7 > 723-725

The proteinogenic amino acid proline has multiple functions in living cells. Depending on whether it is used as a building block in proteins, as a nutrient, or as an osmostress protectant, the cytoplasmic proline con-centration required for these tasks varies dramatically. The soil bacterium Bacillus subtilis solves this problem by precisely regulating and highly integrating catabolic, anabolic, and...

article

Bacterial abl-like genes: production of the archaeal osmolyte $$ {N^{\varepsilon }}{\text{ - acetyl - }}\beta {\text{ - lysine}} $$ by homologous overexpression of the yodP–kamA genes in Bacillus subtilis

Stefan Müller, Tamara Hoffmann, Helena Santos, Stephan H. Saum, more

Applied Microbiology and Biotechnology > 2011 > 91 > 3 > 689-697

$$ {N^{\varepsilon }}{\text{ - acetyl - }}\beta {\text{ - lysine}} $$ is an archaeal compatible solute whose synthesis is mediated by the sequential reactions of the lysine-2,3-aminomutase AblA and the acetyltransferase AblB. α-Lysine serves as the precursor and is converted by AblA to β-lysine, and AblB then acetylates this intermediate to $$ {N^{\varepsilon }}{\text{ - acetyl - }}\beta {\text{...

article

The anaerobic life of Bacillus subtilis: Cloning of the genes encoding the respiratory nitrate reductase system

Tamara Hoffmann, Barbara Troup, Alexandra Szabo, Christoph Hungerer, more

FEMS Microbiology Letters > 1995 > 131 > 2 > 219-225

The Gram-positive soil bacterium Bacillus subtilis, generally regarded as an aerobe, grows under strict anaerobic conditions using nitrate as an electron acceptor and should be designated as a facultative anaerobe. Growth experiments demonstrated a lag phase of 24 to 36 hours after the shift from aerobic, to the onset of anaerobic respiratory growth. Anaerobically adapted cells grew without further...

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