scholarly journals Metabolic exchange and energetic coupling between nutritionally stressed bacterial species, the possible role of QS molecules

2020 ◽  
Author(s):  
David Ranava ◽  
Cassandra Backes ◽  
Ganesan Karthikeyan ◽  
Olivier Ouari ◽  
Audrey Soric ◽  
...  
Keyword(s):  
Species Interactions ◽  
Bacterial Species ◽  
Anaerobic Bacteria ◽  
Species Interaction ◽  
Desulfovibrio Vulgaris ◽  
Physical Interaction ◽  
E Coli ◽  
Metabolic Exchange

AbstractTo clarify the principles controlling inter-species interactions, we previously developed a co-culture model with two anaerobic bacteria, Clostridium acetobutylicum and Desulfovibrio vulgaris Hildenborough, in which nutritional stress for D. vulgaris induced tight cell-cell inter-species interaction. Here we show that exchange of metabolites produced by C. acetobutylicum allows D. vulgaris to duplicate its DNA, and to be energetically viable even without its substrates. Physical interaction between C. acetobutylicum and D. vulgaris (or Escherichia coli and D. vulgaris) is linked to the quorum-sensing molecule AI-2, produced by C. acetobutylicum and E. coli. With nutrients D. vulgaris produces a small molecule that inhibits in vitro the AI-2 activity, and could act as an antagonist in vivo. Sensing of AI-2 by D. vulgaris could induce formation of an intercellular structure that allows directly or indirectly metabolic exchange and energetic coupling between the two bacteria.

scholarly journals Metabolic Exchange and Energetic Coupling between Nutritionally Stressed Bacterial Species: Role of Quorum-Sensing Molecules

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David Ranava ◽  
Cassandra Backes ◽  
Ganesan Karthikeyan ◽  
Olivier Ouari ◽  
Audrey Soric ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Bacterial Species ◽  
Emergent Properties ◽  
Desulfovibrio Vulgaris ◽  
Interspecies Interactions ◽  
Content Type ◽  
Bacterial Communication ◽  
Metabolic Exchange

ABSTRACT Formation of multispecies communities allows nearly every niche on earth to be colonized, and the exchange of molecular information among neighboring bacteria in such communities is key for bacterial success. To clarify the principles controlling interspecies interactions, we previously developed a coculture model with two anaerobic bacteria, Clostridium acetobutylicum (Gram positive) and Desulfovibrio vulgaris Hildenborough (Gram negative, sulfate reducing). Under conditions of nutritional stress for D. vulgaris, the existence of tight cell-cell interactions between the two bacteria induced emergent properties. Here, we show that the direct exchange of carbon metabolites produced by C. acetobutylicum allows D vulgaris to duplicate its DNA and to be energetically viable even without its substrates. We identify the molecular basis of the physical interactions and how autoinducer-2 (AI-2) molecules control the interactions and metabolite exchanges between C. acetobutylicum and D. vulgaris (or Escherichia coli and D. vulgaris). With nutrients, D. vulgaris produces a small molecule that inhibits in vitro the AI-2 activity and could act as an antagonist in vivo. Sensing of AI-2 by D. vulgaris could induce formation of an intercellular structure that allows directly or indirectly metabolic exchange and energetic coupling between the two bacteria. IMPORTANCE Bacteria have usually been studied in single culture in rich media or under specific starvation conditions. However, in nature they coexist with other microorganisms and build an advanced society. The molecular bases of the interactions controlling this society are poorly understood. Use of a synthetic consortium and reducing complexity allow us to shed light on the bacterial communication at the molecular level. This study presents evidence that quorum-sensing molecule AI-2 allows physical and metabolic interactions in the synthetic consortium and provides new insights into the link between metabolism and bacterial communication.

scholarly journals In Vitro and In Vivo Antibacterial Activities of a Novel Glycylcycline, the 9-t-Butylglycylamido Derivative of Minocycline (GAR-936)

1999 ◽  
Vol 43 (4) ◽  
pp. 738-744 ◽  
Author(s):  
P. J. Petersen ◽  
N. V. Jacobus ◽  
W. J. Weiss ◽  
P. E. Sum ◽  
R. T. Testa
Keyword(s):  
Anaerobic Bacteria ◽  
Tetracycline Resistance ◽  
Protective Effects ◽  
Gram Negative ◽  
E Coli ◽  
Resistance Determinants ◽  
Aerobic And Anaerobic ◽  
Ribosomal Protection

ABSTRACT The 9-t-butylglycylamido derivative of minocycline (TBG-MINO) is a recently synthesized member of a novel group of antibiotics, the glycylcyclines. This new derivative, like the first glycylcyclines, theN,N-dimethylglycylamido derivative of minocycline and 6-demethyl-6-deoxytetracycline, possesses activity against bacterial isolates containing the two major determinants responsible for tetracycline resistance: ribosomal protection and active efflux. The in vitro activities of TBG-MINO and the comparative agents were evaluated against strains with characterized tetracycline resistance as well as a spectrum of recent clinical aerobic and anaerobic gram-positive and gram-negative bacteria. TBG-MINO, with an MIC range of 0.25 to 0.5 μg/ml, showed good activity against strains expressing tet(M) (ribosomal protection), tet(A), tet(B),tet(C), tet(D), and tet(K) (efflux resistance determinants). TBG-MINO exhibited similar activity against methicillin-resistant Staphylococcus aureus (MRSA), penicillin-resistant streptococci, and vancomycin-resistant enterococci (MICs at which 90% of strains are inhibited, ≤0.5 μg/ml). TBG-MINO exhibited activity against a wide diversity of gram-negative aerobic and anaerobic bacteria, most of which were less susceptible to tetracycline and minocycline. The in vivo protective effects of TBG-MINO were examined against acute lethal infections in mice caused by Escherichia coli, S. aureus, andStreptococcus pneumoniae isolates. TBG-MINO, administered intravenously, demonstrated efficacy against infections caused byS. aureus including MRSA strains and strains containingtet(K) or tet(M) resistance determinants (median effective doses [ED50s], 0.79 to 2.3 mg/kg of body weight). TBG-MINO demonstrated efficacy against infections caused by tetracycline-sensitive E. coli strains as well asE. coli strains containing either tet(M) or the efflux determinant tet(A), tet(B), ortet(C) (ED50s, 1.5 to 3.5 mg/kg). Overall, TBG-MINO shows antibacterial activity against a wide spectrum of gram-positive and gram-negative aerobic and anaerobic bacteria including strains resistant to other chemotherapeutic agents. The in vivo protective effects, especially against infections caused by resistant bacteria, corresponded with the in vitro activity of TBG-MINO.

scholarly journals Adaptation in a Mouse Colony Monoassociated with Escherichia coli K-12 for More than 1,000 Days

2010 ◽  
Vol 76 (14) ◽  
pp. 4655-4663 ◽  
Author(s):  
Sean M. Lee ◽  
Aaron Wyse ◽  
Aaron Lesher ◽  
Mary Lou Everett ◽  
Linda Lou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rates ◽  
Bacterial Species ◽  
Intestinal Flora ◽  
Average Density ◽  
Host Bacterium ◽  
E Coli ◽  
K 12

ABSTRACT Although mice associated with a single bacterial species have been used to provide a simple model for analysis of host-bacteria relationships, bacteria have been shown to display adaptability when grown in a variety of novel environments. In this study, changes associated with the host-bacterium relationship in mice monoassociated with Escherichia coli K-12 over a period of 1,031 days were evaluated. After 80 days, phenotypic diversification of E. coli was observed, with the colonizing bacteria having a broader distribution of growth rates in the laboratory than the parent E. coli. After 1,031 days, which included three generations of mice and an estimated 20,000 generations of E. coli, the initially homogeneous bacteria colonizing the mice had evolved to have widely different growth rates on agar, a potential decrease in tendency for spontaneous lysis in vivo, and an increased tendency for spontaneous lysis in vitro. Importantly, mice at the end of the experiment were colonized at an average density of bacteria that was more than 3-fold greater than mice colonized on day 80. Evaluation of selected isolates on day 1,031 revealed unique restriction endonuclease patterns and differences between isolates in expression of more than 10% of the proteins identified by two-dimensional electrophoresis, suggesting complex changes underlying the evolution of diversity during the experiment. These results suggest that monoassociated mice might be used as a tool for characterizing niches occupied by the intestinal flora and potentially as a method of targeting the evolution of bacteria for applications in biotechnology.

scholarly journals FtsW exhibits distinct processive motions driven by either septal cell wall synthesis or FtsZ treadmilling in E. coli

2019 ◽  
Author(s):  
Xinxing Yang ◽  
Ryan McQuillen ◽  
Zhixin Lyu ◽  
Polly Phillips-Mason ◽  
Ana De La Cruz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Single Molecule ◽  
Bacterial Cell ◽  
Spatial Information ◽  
Bacterial Species ◽  
E Coli ◽  
Slow Moving

AbstractDuring bacterial cell division, synthesis of new septal peptidoglycan (sPG) is crucial for successful cytokinesis and cell pole morphogenesis. FtsW, a SEDS (Shape, Elongation, Division and Sporulation) family protein and an indispensable component of the cell division machinery in all walled bacterial species, was recently identified in vitro as a new monofunctional peptidoglycan glycosyltransferase (PGTase). FtsW and its cognate monofunctional transpeptidase (TPase) class B penicillin binding protein (PBP3 or FtsI in E. coli) may constitute the essential, bifunctional sPG synthase specific for new sPG synthesis. Despite its importance, the septal PGTase activity of FtsW has not been documented in vivo. How its activity is spatiotemporally regulated in vivo has also remained unknown. Here we investigated the septal PGTase activity and dynamics of FtsW in E. coli cells using a combination of single-molecule imaging and genetic manipulations. We show that FtsW exhibits robust activity to incorporate an N-acetylmuramic acid analog at septa in the absence of other known PGTases, confirming FtsW as the essential septum-specific PGTase in vivo. Notably, we identified two populations of processive moving FtsW molecules at septa. A fast-moving population is driven by the treadmilling dynamics of FtsZ and independent of sPG synthesis. A slow-moving population is driven by active sPG synthesis and independent of FtsZ’s treadmilling dynamics. We further identified that FtsN, a potential sPG synthesis activator, plays an important role in promoting the slow-moving, sPG synthesis-dependent population. Our results support a two-track model, in which inactive sPG synthase molecules follow the fast treadmilling “Z-track” to be distributed along the septum; FtsN promotes their release from the “Z-track” to become active in sPG synthesis on the slow “sPG-track”. This model explains how the spatial information is integrated into the regulation of sPG synthesis activity and suggests a new mechanistic framework for the spatiotemporal coordination of bacterial cell wall constriction.

scholarly journals Molecular characterization of the TonB2 protein from the fish pathogen Vibrio anguillarum

2009 ◽  
Vol 418 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Claudia S. López ◽  
R. Sean Peacock ◽  
Jorge H. Crosa ◽  
Hans J. Vogel
Keyword(s):  
Amino Acids ◽  
Solution Structure ◽  
Bacterial Species ◽  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
E Coli ◽  
Terminal Domain ◽  
C Terminus

In the fish pathogen Vibrio anguillarum the TonB2 protein is essential for the uptake of the indigenous siderophore anguibactin. Here we describe deletion mutants and alanine replacements affecting the final six amino acids of TonB2. Deletions of more than two amino acids of the TonB2 C-terminus abolished ferric-anguibactin transport, whereas replacement of the last three residues resulted in a protein with wild-type transport properties. We have solved the high-resolution solution structure of the TonB2 C-terminal domain by NMR spectroscopy. The core of this domain (residues 121–206) has an αββαβ structure, whereas residues 76–120 are flexible and extended. This overall folding topology is similar to the Escherichia coli TonB C-terminal domain, albeit with two differences: the β4 strand found at the C-terminus of TonB is absent in TonB2, and loop 3 is extended by 9 Å (0.9 nm) in TonB2. By examining several mutants, we determined that a complete loop 3 is not essential for TonB2 activity. Our results indicate that the β4 strand of E. coli TonB is not required for activity of the TonB system across Gram-negative bacterial species. We have also determined, through NMR chemical-shift-perturbation experiments, that the E. coli TonB binds in vitro to the TonB box from the TonB2-dependent outer membrane transporter FatA; moreover, it can substitute in vivo for TonB2 during ferric-anguibactin transport in V. anguillarum. Unexpectedly, TonB2 did not bind in vitro to the FatA TonB-box region, suggesting that additional factors may be required to promote this interaction. Overall our results indicate that TonB2 is a representative of a different class of TonB proteins.

scholarly journals Small-molecule antibiotic inhibitors of post-translational protein secretion

2020 ◽  
Author(s):  
Mohamed Belal Hamed ◽  
Ewa Burchacka ◽  
Liselotte Angus ◽  
Arnaud Marchand ◽  
Jozefien De Geyter ◽  
...  
Keyword(s):  
Small Molecule ◽  
Bacterial Resistance ◽  
Bacterial Species ◽  
Attractive Potential ◽  
E Coli ◽  
Small Molecule Compound ◽  
Potential Alternative ◽  
Structural Classes

AbstractThe increasing problem of bacterial resistance to antibiotics underscores the urgent need for new antibacterials. The Sec preprotein export pathway is an attractive potential alternative target. It is essential for bacterial viability and includes components that are absent from eukaryotes. Here we used a new high throughput in vivo screen based on the secretion and activity of alkaline phosphatase (PhoA), a Sec-dependent secreted enzyme that becomes active in the periplasm. The assay was optimized for a luminescence-based substrate and was used to screen a ~240K small molecule compound library. After hit confirmation and analoging, fourteen HTS secretion inhibitors (HSI), belonging to 8 structural classes, were identified (IC50 <60 μM). The inhibitors were also evaluated as antibacterials against 19 Gram− and Gram+ bacterial species (including those from the WHO top pathogens list). Seven of them, HSI#6, 9; HSI#1, 5, 10 and HSI#12, 14 representing three structural families were microbicidals. HSI#6 was the most potent (IC50 of 0.4-8.7 μM), against 13 species of both Gram− and Gram+ bacteria. HSI#1, 5, 9 and 10 inhibited viability of Gram+ bacteria with IC50 ~6.9-77.8 μM. HSI#9, 12 and 14 inhibited viability of E. coli strains with IC50 <65 μM. Moreover, HSI#1, 5 and 10 inhibited viability of an E. coli strain missing TolC to improve permeability with IC50 4-14 μM, indicating their inability to penetrate the outer membrane. In vitro assays revealed that antimicrobial activity was not related to inhibition of the SecA component of the translocase and hence HSI molecules may target new unknown components that affect secretion. The results provide proof of principle for our approach, and new starting compounds for optimization.

scholarly journals In vitro and in vivo antibacterial activities of CS-834, a novel oral carbapenem.

1997 ◽  
Vol 41 (12) ◽  
pp. 2652-2663 ◽  
Author(s):  
T Fukuoka ◽  
S Ohya ◽  
Y Utsui ◽  
H Domon ◽  
T Takenouchi ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Beta Lactamases ◽  
E Coli ◽  
Resistant Strains ◽  
Clinically Significant

CS-834 is a novel oral carbapenem antibiotic. This compound is an ester-type prodrug of the active metabolite R-95867. The antibacterial activity of R-95867 was tested against 1,323 clinical isolates of 35 species and was compared with those of oral cephems, i.e., cefteram, cefpodoxime, cefdinir, and cefditoren, and that of a parenteral carbapenem, imipenem. R-95867 exhibited a broad spectrum of activity covering both gram-positive and -negative aerobes and anaerobes. Its activity was superior to those of the other compounds tested against most of the bacterial species tested. R-95867 showed potent antibacterial activity against clinically significant pathogens: methicillin-susceptible Staphylococcus aureus including ofloxacin-resistant strains, Streptococcus pneumoniae including penicillin-resistant strains, Clostridium perfringens, Neisseria spp., Moraxella catarrhalis, most members of the family Enterobacteriaceae, and Haemophilus influenzae (MIC at which 90% of strains are inhibited, < or =0.006 to 0.78 microg/ml). R-95867 was quite stable to hydrolysis by most of the beta-lactamases tested except the metallo-beta-lactamases from Stenotrophomonas maltophilia and Bacteroides fragilis. R-95867 showed potent bactericidal activity against S. aureus and Escherichia coli. Penicillin-binding proteins 1 and 4 of S. aureus and 1Bs, 2, 3, and 4 of E. coli had high affinities for R-95867. The in vivo efficacy of CS-834 was evaluated in murine systemic infections caused by 16 strains of gram-positive and -negative pathogens. The efficacy of CS-834 was in many cases superior to those of cefteram pivoxil, cefpodoxime proxetil, cefdinir, and cefditoren pivoxil, especially against infections caused by S. aureus, penicillin-resistant S. pneumoniae, E. coli, Citrobacter freundii, and Proteus vulgaris. Among the drugs tested, CS-834 showed the highest efficacy against experimental pneumonia in mice caused by penicillin-resistant S. pneumoniae.

scholarly journals One-Carbon Metabolic Pathway Rewiring in Escherichia coli Reveals an Evolutionary Advantage of 10-Formyltetrahydrofolate Synthetase (Fhs) in Survival under Hypoxia

2014 ◽  
Vol 197 (4) ◽  
pp. 717-726 ◽  
Author(s):  
Shivjee Sah ◽  
Srinivas Aluri ◽  
Kervin Rex ◽  
Umesh Varshney
Keyword(s):  
Escherichia Coli ◽  
Anaerobic Bacteria ◽  
High Capacity ◽  
Natural Occurrence ◽  
Content Type ◽  
E Coli ◽  
Formyltetrahydrofolate Synthetase ◽  
Facultative Anaerobic Bacteria

In cells,N10-formyltetrahydrofolate (N10-fTHF) is required for formylation of eubacterial/organellar initiator tRNA and purine nucleotide biosynthesis. Biosynthesis ofN10-fTHF is catalyzed by 5,10-methylene-tetrahydrofolate dehydrogenase/cyclohydrolase (FolD) and/or 10-formyltetrahydrofolate synthetase (Fhs). All eubacteria possess FolD, but some possess both FolD and Fhs. However, the reasons for possessing Fhs in addition to FolD have remained unclear. We usedEscherichia coli, which naturally lacksfhs, as our model. We show that inE. coli, the essential function offolDcould be replaced byClostridium perfringensfhswhen it was provided on a medium-copy-number plasmid or integrated as a single-copy gene in the chromosome. Thefhs-supportedfolDdeletion (ΔfolD) strains grow well in a complex medium. However, these strains require purines and glycine as supplements for growth in M9 minimal medium. Thein vivolevels ofN10-fTHF in the ΔfolDstrain (supported by plasmid-bornefhs) were limiting despite the high capacity of the available Fhs to synthesizeN10-fTHFin vitro. Auxotrophy for purines could be alleviated by supplementing formate to the medium, and that for glycine was alleviated by engineering THF import into the cells. The ΔfolDstrain (harboringfhson the chromosome) showed a high NADP+-to-NADPH ratio and hypersensitivity to trimethoprim. The presence offhsinE. coliwas disadvantageous for its aerobic growth. However, under hypoxia,E. colistrains harboringfhsoutcompeted those lacking it. The computational analysis revealed a predominant natural occurrence offhsin anaerobic and facultative anaerobic bacteria.

scholarly journals Gastrointestinal effects of prebiotics

2002 ◽  
Vol 87 (S2) ◽  
pp. S145-S151 ◽  
Author(s):  
J. H. Cummings ◽  
G. T. Macfarlane
Keyword(s):  
Large Intestine ◽  
Bacterial Species ◽  
Anaerobic Bacteria ◽  
Short Chain Fatty Acids ◽  
Natural Resistance ◽  
Laxative Effects ◽  
Normal Human ◽  
Human Large Intestine

The defining effect of prebiotics is to stimulate selectively the growth of bifidobacteria and lactobacilli in the gut and, thereby, increase the body's natural resistance to invading pathogens. Prebiotic carbohydrates may also have additional, less specific, benefits because they are fermented in the large intestine. The prebiotic carbohydrates that have been evaluated in humans at the present time largely consist of fructans or galactans. There is consistent evidence from in vitro and in vivo studies that these are not digested by normal human enzymes, but are readily fermented by anaerobic bacteria in the large intestine. There are no reports of faecal recovery of measurable quantities of prebiotic carbohydrates. Through fermentation in the large intestine, prebiotic carbohydrates yield short-chain fatty acids, stimulate the growth of many bacterial species in addition to the selective effects on lactobacilli and bifidobacteria, they can also produce gas. Along with other fermented carbohydrates, prebiotics have mild laxative effects, although this has proved difficult to demonstrate in human studies because the magnitude of laxation is small. Potentially, the most important effect of prebiotic carbohydrates is to strengthen the body's resistance to invading pathogens and, thereby, prevent episodes of diarrhoea. At the present time, this effect has not been convincingly demonstrated in either adults or children, although there have been attempts to ameliorate the diarrhoea associated with antibiotics and travel, but without success. However, prebiotic carbohydrates clearly have significant and distinctive physiological effects in the human large intestine, and on the basis of this it is likely that they will ultimately be shown to be beneficial to health.

scholarly journals Autophosphorylation of Phosphoglucosamine Mutase from Escherichia coli

2000 ◽  
Vol 182 (5) ◽  
pp. 1280-1285 ◽  
Author(s):  
Laure Jolly ◽  
Frédérique Pompeo ◽  
Jean van Heijenoort ◽  
Florence Fassy ◽  
Dominique Mengin-Lecreulx
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Site Directed Mutagenesis ◽  
Rabbit Muscle ◽  
E Coli ◽  
Ping Pong ◽  
Covalently Linked ◽  
Hydrolysis Of

ABSTRACT Phosphoglucosamine mutase (GlmM) catalyzes the formation of glucosamine-1-phosphate from glucosamine-6-phosphate, an essential step in the pathway for UDP-N-acetylglucosamine biosynthesis in bacteria. This enzyme must be phosphorylated to be active and acts according to a ping-pong mechanism involving glucosamine-1,6-diphosphate as an intermediate (L. Jolly, P. Ferrari, D. Blanot, J. van Heijenoort, F. Fassy, and D. Mengin-Lecreulx, Eur. J. Biochem. 262:202–210, 1999). However, the process by which the initial phosphorylation of the enzyme is achieved in vivo remains unknown. Here we show that the phosphoglucosamine mutase fromEscherichia coli autophosphorylates in vitro in the presence of [32P]ATP. The same is observed with phosphoglucosamine mutases from other bacterial species, yeastN-acetylglucosamine-phosphate mutase, and rabbit muscle phosphoglucomutase. Labeling of the E. coli GlmM enzyme with [32P]ATP requires the presence of a divalent cation, and the label is subsequently lost when the enzyme is incubated with either of its substrates. Analysis of enzyme phosphorylation by high-pressure liquid chromatography and coupled mass spectrometry confirms that only one phosphate has been covalently linked to the enzyme. Only phosphoserine could be detected after acid hydrolysis of the labeled protein, and site-directed mutagenesis of serine residues located in or near the active site identifies the serine residue at position 102 as the site of autophosphorylation of E. coliGlmM.

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