Characterisation of thel-Cystine β-Lyase PatB fromPhaeobacter inhibens: An Enzyme Involved in the Biosynthesis of the Marine Antibiotic Tropodithietic Acid

ChemBioChem ◽  
2017 ◽  
Vol 18 (22) ◽  
pp. 2260-2267 ◽  
Author(s):  
Jeroen S. Dickschat ◽  
Jan Rinkel ◽  
Tim Klapschinski ◽  
Jörn Petersen
Keyword(s):  
Tropodithietic Acid

scholarly journals Contributions of tropodithietic acid and biofilm formation to the probiotic activity of Phaeobacter inhibens

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Wenjing Zhao ◽  
Christine Dao ◽  
Murni Karim ◽  
Marta Gomez-Chiarri ◽  
David Rowley ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Tropodithietic Acid ◽  
Probiotic Activity ◽  
Phaeobacter Inhibens

scholarly journals Characterisation of Non-Autoinducing Tropodithietic Acid (TDA) Production from Marine Sponge Pseudovibrio Species

Marine Drugs ◽  
2014 ◽  
Vol 12 (12) ◽  
pp. 5960-5978 ◽  
Author(s):  
Catriona Harrington ◽  
F. Reen ◽  
Marlies Mooij ◽  
Fiona Stewart ◽  
Jean-Baptiste Chabot ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Tropodithietic Acid

scholarly journals Influence of Iron on Production of the Antibacterial Compound Tropodithietic Acid and Its Noninhibitory Analog in Phaeobacter inhibens

2015 ◽  
Vol 82 (2) ◽  
pp. 502-509 ◽  
Author(s):  
Paul W. D'Alvise ◽  
Christopher B. W. Phippen ◽  
Kristian F. Nielsen ◽  
Lone Gram
Keyword(s):  
Mass Spectrometry ◽  
Antibacterial Activity ◽  
High Resolution Mass Spectrometry ◽  
Biologically Active ◽  
Brown Pigment ◽  
Marine Broth ◽  
Content Type ◽  
Tropodithietic Acid ◽  
Antibacterial Compound ◽  
Phaeobacter Inhibens

ABSTRACTTropodithietic acid (TDA) is an antibacterial compound produced by somePhaeobacterandRuegeriaspp. of theRoseobacterclade. TDA production is studied in marine broth or agar since antibacterial activity in other media is not observed. The purpose of this study was to determine how TDA production is influenced by substrate components. High concentrations of ferric citrate, as present in marine broth, or other iron sources were required for production of antibacterially active TDA. However, when supernatants of noninhibitory, low-iron cultures ofPhaeobacter inhibenswere acidified, antibacterial activity was detected in a bioassay. The absence of TDA in nonacidified cultures and the presence of TDA in acidified cultures were verified by liquid chromatography–high-resolution mass spectrometry. A noninhibitory TDA analog (pre-TDA) was produced byP. inhibens,Ruegeria mobilisF1926, andPhaeobactersp. strain 27-4 under low-iron concentrations and was instantaneously converted to TDA when pH was lowered. Production of TDA in the presence of Fe3+coincides with formation of a dark brown substance, which could be precipitated by acid addition. From this brown pigment TDA could be liberated slowly with aqueous ammonia, and both direct-infusion mass spectrometry and elemental analysis indicated a [FeIII(TDA)2]xcomplex. The pigment could also be produced by precipitation of pure TDA with FeCl3. Our results raise questions about how biologically active TDA is produced in natural marine settings where iron is typically limited and whether the affinity of TDA to iron points to a physiological or ecological function of TDA other than as an antibacterial compound.

scholarly journals Cytotoxic Effects of Tropodithietic Acid on Mammalian Clonal Cell Lines of Neuronal and Glial Origin

Marine Drugs ◽  
2015 ◽  
Vol 13 (12) ◽  
pp. 7113-7123 ◽  
Author(s):  
Heidi Wichmann ◽  
Farina Vocke ◽  
Thorsten Brinkhoff ◽  
Meinhard Simon ◽  
Christiane Richter-Landsberg
Keyword(s):  
Cell Lines ◽  
Cytotoxic Effects ◽  
Clonal Cell ◽  
Tropodithietic Acid ◽  
Clonal Cell Lines

scholarly journals Mode of action and resistance studies unveil new roles for tropodithietic acid as an anticancer agent and the γ-glutamyl cycle as a proton sink

2016 ◽  
Vol 113 (6) ◽  
pp. 1630-1635 ◽  
Author(s):  
Maxwell Z. Wilson ◽  
Rurun Wang ◽  
Zemer Gitai ◽  
Mohammad R. Seyedsayamdost
Keyword(s):  
Broad Spectrum ◽  
Marine Bacteria ◽  
Anticancer Agents ◽  
Mode Of Action ◽  
Resistance Mechanism ◽  
Acid Resistance ◽  
Structural Features ◽  
Anticancer Activities ◽  
Tropodithietic Acid ◽  
Biochemical Analyses

While we have come to appreciate the architectural complexity of microbially synthesized secondary metabolites, far less attention has been paid to linking their structural features with possible modes of action. This is certainly the case with tropodithietic acid (TDA), a broad-spectrum antibiotic generated by marine bacteria that engage in dynamic symbioses with microscopic algae. TDA promotes algal health by killing unwanted marine pathogens; however, its mode of action (MoA) and significance for the survival of an algal–bacterial miniecosystem remains unknown. Using cytological profiling, we herein determine the MoA of TDA and surprisingly find that it acts by a mechanism similar to polyether antibiotics, which are structurally highly divergent. We show that like polyether drugs, TDA collapses the proton motive force by a proton antiport mechanism, in which extracellular protons are exchanged for cytoplasmic cations. The α-carboxy-tropone substructure is ideal for this purpose as the proton can be carried on the carboxyl group, whereas the basicity of the tropylium ion facilitates cation export. Based on similarities to polyether anticancer agents we have further examined TDA’s cytotoxicity and find it to exhibit potent, broad-spectrum anticancer activities. These results highlight the power of MoA-profiling technologies in repurposing old drugs for new targets. In addition, we identify an operon that confers TDA resistance to the producing marine bacteria. Bioinformatic and biochemical analyses of these genes lead to a previously unknown metabolic link between TDA/acid resistance and the γ-glutamyl cycle. The implications of this resistance mechanism in the context of the algal-bacterial symbiosis are discussed.

scholarly journals Genetic Dissection of Tropodithietic Acid Biosynthesis by Marine Roseobacters

2008 ◽  
Vol 74 (5) ◽  
pp. 1535-1545 ◽  
Author(s):  
Haifeng Geng ◽  
Jesper Bartholin Bruhn ◽  
Kristian F. Nielsen ◽  
Lone Gram ◽  
Robert Belas
Keyword(s):  
Low Frequency ◽  
Bacterial Chemotaxis ◽  
Metagenomic Library ◽  
Antibiotic Activity ◽  
Insertion Mutagenesis ◽  
Brown Pigment ◽  
Symbiotic Association ◽  
Genetic Dissection ◽  
Biogeographical Distribution ◽  
Tropodithietic Acid

ABSTRACT The symbiotic association between the roseobacter Silicibacter sp. strain TM1040 and the dinoflagellate Pfiesteria piscicida involves bacterial chemotaxis to dinoflagellate-produced dimethylsulfoniopropionate (DMSP), DMSP demethylation, and ultimately a biofilm on the surface of the host. Biofilm formation is coincident with the production of an antibiotic and a yellow-brown pigment. In this report, we demonstrate that the antibiotic is a sulfur-containing compound, tropodithietic acid (TDA). Using random transposon insertion mutagenesis, 12 genes were identified as critical for TDA biosynthesis by the bacteria, and mutation in any one of these results in a loss of antibiotic activity (Tda−) and pigment production. Unexpectedly, six of the genes, referred to as tdaA-F, could not be found on the annotated TM1040 genome and were instead located on a previously unidentified plasmid (ca. 130 kb; pSTM3) that exhibited a low frequency of spontaneous loss. Homologs of tdaA and tdaB from Silicibacter sp. strain TM1040 were identified by mutagenesis in another TDA-producing roseobacter, Phaeobacter sp. strain 27-4, which also possesses two large plasmids (ca. 60 and ca. 70 kb, respectively), and tda genes were found by DNA-DNA hybridization in 88% of a diverse collection of nine roseobacters with known antibiotic activity. These data suggest that roseobacters may use a common pathway for TDA biosynthesis that involves plasmid-encoded proteins. Using metagenomic library databases and a bioinformatics approach, differences in the biogeographical distribution between the critical TDA synthesis genes were observed. The implications of these results to roseobacter survival and the interaction between TM1040 and its dinoflagellate host are discussed.

scholarly journals Expression of Tropodithietic Acid Biosynthesis Is Controlled by a Novel Autoinducer

2010 ◽  
Vol 192 (17) ◽  
pp. 4377-4387 ◽  
Author(s):  
Haifeng Geng ◽  
Robert Belas
Keyword(s):  
Gene Expression ◽  
Biologically Active ◽  
Biogeochemical Processes ◽  
Wild Type ◽  
Acid Biosynthesis ◽  
Transcriptional Fusion ◽  
Tropodithietic Acid ◽  
Eukaryotic Microorganisms ◽  
Close Proximity ◽  
Liquid Culturing

ABSTRACT The interactions between marine prokaryotic and eukaryotic microorganisms are crucial to many biological and biogeochemical processes in the oceans. Often the interactions are mutualistic, as in the symbiosis between phytoplankton, e.g., the dinoflagellate Pfiesteria piscicida and Silicibacter sp. TM1040, a member of the Roseobacter taxonomic lineage. It is hypothesized that an important component of this symbiosis is bacterial production of tropodithietic acid (TDA), a biologically active tropolone compound whose synthesis requires the expression of tda ABCDEF (tdaA-F), as well as six additional genes (cysI, malY, paaIJK, and tdaH). The factors controlling tda gene expression are not known, although growth in laboratory standing liquid cultures drastically increases TDA levels. In this report, we measured the transcription of tda genes to gain a greater understanding of the factors controlling their expression. While the expression of tdaAB was constitutive, tdaCDE and tdaF mRNA increased significantly (3.7- and 17.4-fold, respectively) when cells were grown in standing liquid broth compared to their levels with shaking liquid culturing. No transcription of tdaC was detected when a tdaC p::lacZ transcriptional fusion was placed in 11 of the 12 Tda− mutant backgrounds, with cysI being the sole exception. The expression of tdaC could be restored to 9 of the remaining 11 Tda− mutants—tdaA and tdaH failed to respond—by placing wild-type (Tda+) strains in close proximity or by supplying exogenous TDA to the mutant, suggesting that TDA induces tda gene expression. These results indicate that TDA acts as an autoinducer of its own synthesis and suggest that roseobacters may use TDA as a quorum signal.

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