scholarly journals Beyond Antagonism: The Interaction Between Candida Species and Pseudomonas aeruginosa

2019 ◽  
Vol 5 (2) ◽  
pp. 34 ◽  
Author(s):  
Fourie ◽  
Pohl
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Future Perspectives ◽  
Factors Influencing ◽  
Acid Metabolites ◽  
Opportunistic Pathogenic ◽  
Fatty Acid Metabolites ◽  
Wall Components

There are many examples of the interaction between prokaryotes and eukaryotes. One such example is the polymicrobial colonization/infection by the various opportunistic pathogenic yeasts belonging to the genus Candida and the ubiquitous bacterium, Pseudomonas aeruginosa. Although this interaction has simplistically been characterized as antagonistic to the yeast, this review highlights the complexity of the interaction with various factors influencing both microbes. The first section deals with the interactions in vitro, looking specifically at the role of cell wall components, quorum sensing molecules, phenazines, fatty acid metabolites and competition for iron in the interaction. The second part of this review places all these interactions in the context of various infection or colonization sites, i.e., lungs, wounds, and the gastrointestinal tract. Here we see that the role of the host, as well as the methodology used to establish co-infection, are important factors, influencing the outcome of the disease. Suggested future perspectives for the study of this interaction include determining the influence of newly identified participants of the QS network of P. aeruginosa, oxylipin production by both species, as well as the genetic and phenotypic plasticity of these microbes, on the interaction and outcome of co-infection.

scholarly journals Direct and indirect interactions promote complexes of the lipoprotein LbcA, the CtpA protease and its substrates, and other cell wall proteins in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Dolonchapa Chakraborty ◽  
Andrew J. Darwin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Protein Complexes ◽  
Associated Proteins ◽  
Carboxyl Terminal ◽  
Multiple Species ◽  
Processing Protease ◽  
Enzyme Complexes

The Pseudomonas aeruginosa lipoprotein LbcA was discovered because it copurified with and promoted the activity of CtpA, a carboxyl-terminal processing protease (CTP) required for type III secretion system function, and for virulence in a mouse model of acute pneumonia. In this study we explored the role of LbcA by determining its effect on the proteome and its participation in protein complexes. lbcA and ctpA null mutations had strikingly similar effects on the proteome, suggesting that assisting CtpA might be the most impactful role of LbcA in the bacterial cell. Independent complexes containing LbcA and CtpA, or LbcA and substrate, were isolated from P. aeruginosa cells, indicating that LbcA facilitates proteolysis by recruiting the protease and its substrates independently. An unbiased examination of proteins that copurified with LbcA revealed an enrichment for proteins associated with the cell wall. One of these copurification partners was found to be a new CtpA substrate, and the first substrate that is not a peptidoglycan hydrolase. Many of the other LbcA copurification partners are known or predicted peptidoglycan hydrolases. However, some of these LbcA copurification partners were not cleaved by CtpA, and an in vitro assay revealed that while CtpA and all of its substrates bound to LbcA directly, these non-substrates did not. Subsequent experiments suggested that the non substrates might co-purify with LbcA by participating in multi-enzyme complexes containing LbcA-binding CtpA substrates. IMPORTANCE Carboxyl-terminal processing proteases (CTPs) are widely conserved and associated with the virulence of several bacteria, including CtpA in Pseudomonas aeruginosa . CtpA copurifies with the uncharacterized lipoprotein, LbcA. This study shows that the most impactful role of LbcA might be to promote CtpA-dependent proteolysis, and that it achieves this as a scaffold for CtpA and its substrates. It also reveals that LbcA copurification partners are enriched for cell wall-associated proteins, one of which is a novel CtpA substrate. Some of the LbcA copurification partners are not cleaved by CtpA, but might copurify with LbcA because they participate in multi-enzyme complexes containing CtpA substrates. These findings are important, because CTPs and their associated proteins affect peptidoglycan remodeling and virulence in multiple species.

scholarly journals Direct and indirect interactions promote complexes of the lipoprotein LbcA, the CtpA protease and its substrates, and other cell wall proteins in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Dolonchapa Chakraborty ◽  
Andrew J Darwin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Type Iii Secretion ◽  
Protein Complexes ◽  
Peptidoglycan Hydrolases ◽  
Carboxyl Terminal ◽  
Processing Protease ◽  
Enzyme Complexes

The Pseudomonas aeruginosa lipoprotein LbcA was discovered because it copurified with and promoted the activity of CtpA, a carboxyl-terminal processing protease (CTP) required for type III secretion system function, and for virulence in a mouse model of acute pneumonia. In this study we explored the role of LbcA by determining its effect on the proteome and its participation in protein complexes. lbcA and ctpA null mutations had strikingly similar effects on the proteome, suggesting that facilitating CtpA might be the most impactful role of LbcA in the bacterial cell. Independent complexes containing LbcA and CtpA, or LbcA and substrate, were isolated from P. aeruginosa cells, indicating that LbcA facilitates proteolysis by recruiting the protease and its substrates independently. An unbiased examination of proteins that copurified with LbcA revealed an enrichment for proteins associated with the cell wall. One of these copurification partners was found to be a new CtpA substrate, and the first substrate that is not a peptidoglycan hydrolase. Many of the other LbcA copurification partners are known or predicted peptidoglycan hydrolases. However, some of these LbcA copurification partners were not cleaved by CtpA, and an in vitro assay revealed that while CtpA and all of its substrates bound to LbcA directly, these non-substrates did not. Subsequent experiments suggested that the non substrates might co-purify with LbcA by participating in multi-enzyme complexes containing LbcA-binding CtpA substrates.

scholarly journals Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa

2018 ◽  
Vol 78 (2) ◽  
pp. 290-300
Author(s):  
S. Vimalnath ◽  
H. Ravishankar ◽  
C. Schwandt ◽  
R. V. Kumar ◽  
S. Subramanian
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Treatment Method ◽  
Enzymatic Treatment ◽  
Intact Cells ◽  
Cell Wall Components ◽  
Before And After ◽  
Pseudo Second Order ◽  
Wall Components

Abstract The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L−1 at pH 6.2 and temperature 29 ± 1 °C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of −30.7 kJ mol−1, indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment.

In vitro studies of an alkaline phosphatase – cell wall complex from Pseudomonas aeruginosa

1975 ◽  
Vol 21 (1) ◽  
pp. 9-16 ◽  
Author(s):  
D. F. Day ◽  
J. M. Ingram
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Alkaline Phosphatase ◽  
Cell Wall ◽  
Complex Formation ◽  
Wall Material ◽  
Outer Cell ◽  
Whole Cells ◽  
Wall Components ◽  
Outer Cell Wall

Alkaline phosphatase (APase) of Pseudomonas aeruginosa exists primarily in the periplasmic region of the cell, i.e., between the cytoplasmic membrane and the outer tripartite layer. The enzyme is also found in the culture filtrate or associated with the outer layer of the cell wall. APase forms a complex with released outer cell wall material, and lipopolysaccharide (LPS) is associated with the complex. Since the enzyme was purified to homogeneity, it became desirable to determine whether complex formation with LPS, or the outer cell wall, affected any properties of the purified phosphatase. The ratio of activities of purified APase with p-nitrophenylphosphate and β-glycerolphosphate as substrates is about 4:1. The ratio of activities with enzyme complexed with LPS is about 1:1. The energy of activation of sucrose or magnesium released enzyme is 9500 cal/mol whereas the values for purified enzyme plus LPS, purified enzyme, purified enzyme plus phosphatidylethanolamine (PE), and purified enzyme plus LPS plus PE range from 3400 to 8700 cal/mol. These changes occur in the physiological temperature range, 27 to 39C, of this organism. Sucrose-released enzyme in the presence of substrate is inactivated at 47C whereas pure enzyme plus substrate is affected at 41C. The addition of LPS, PE, or a combination of both increases the temperature of inactivation from 45 to 51C. The results suggest that certain properties of the purified enzyme differ from those of the enzyme released from whole cells by either sucrose or magnesium resuspension. The addition of cell wall components such as LPS and PE to purified APase restores these properties. The evidence suggests that artificial complex formation changes the environment of the enzyme protein such that the environment now resembles that which exists within the whole cell wall.

scholarly journals Contribution of Drugs Interfering with Protein and Cell Wall Synthesis to the Persistence of Pseudomonas aeruginosa Biofilms: An In Vitro Model

2021 ◽  
Vol 22 (4) ◽  
pp. 1628
Author(s):  
Gianmarco Mangiaterra ◽  
Elisa Carotti ◽  
Salvatore Vaiasicca ◽  
Nicholas Cedraro ◽  
Barbara Citterio ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Bacterial Population ◽  
In Vitro Model ◽  
Biofilm Production ◽  
Lung Infections ◽  
Vitro Model ◽  
High Doses

The occurrence of Pseudomonas aeruginosa (PA) persisters, including viable but non-culturable (VBNC) forms, subpopulations of tolerant cells that can survive high antibiotic doses, is the main reason for PA lung infections failed eradication and recurrence in Cystic Fibrosis (CF) patients, subjected to life-long, cyclic antibiotic treatments. In this paper, we investigated the role of subinhibitory concentrations of different anti-pseudomonas antibiotics in the maintenance of persistent (including VBNC) PA cells in in vitro biofilms. Persisters were firstly selected by exposure to high doses of antibiotics and their abundance over time evaluated, using a combination of cultural, qPCR and flow cytometry assays. Two engineered GFP-producing PA strains were used. The obtained results demonstrated a major involvement of tobramycin and bacterial cell wall-targeting antibiotics in the resilience to starvation of VBNC forms, while the presence of ciprofloxacin and ceftazidime/avibactam lead to their complete loss. Moreover, a positive correlation between tobramycin exposure, biofilm production and c-di-GMP levels was observed. The presented data could allow a deeper understanding of bacterial population dynamics during the treatment of recurrent PA infections and provide a reliable evaluation of the real efficacy of the antibiotic treatments against the bacterial population within the CF lung.

Multiple Agents Potentiate α1-Adrenoceptor–induced Conduction Depression in Canine Cardiac Purkinje Fibers

2000 ◽  
Vol 92 (6) ◽  
pp. 1713-1721 ◽  
Author(s):  
Alexander H. Kulier ◽  
Lawrence A. Turner ◽  
Sanja Vodanovic ◽  
Stephen Contney ◽  
David A. Lathrop ◽  
...  
Keyword(s):  
Membrane Properties ◽  
Cell Coupling ◽  
Purkinje Fibers ◽  
Palmitoyl Carnitine ◽  
Cardiac Purkinje Fibers ◽  
Phase 0 ◽  
Acid Metabolites ◽  
Fatty Acid Metabolites

Background Halothane more so than isoflurane potentiates an alpha1-adrenoceptor (alpha1-AR)-mediated action of epinephrine that abnormally slows conduction in Purkinje fibers and may facilitate reentrant arrhythmias. This adverse drug interaction was further evaluated by examining conduction responses to epinephrine in combination with thiopental and propofol, which "sensitize" or reduce the dose of epinephrine required to induce arrhythmias in the heart, and with etomidate, which does not, and responses to epinephrine with verapamil, lidocaine, and l-palmitoyl carnitine, a potential ischemic metabolite. Methods Action potentials and conduction times were measured in vitro using two microelectrodes in groups of canine Purkinje fibers stimulated at 150 pulses/min. Conduction was evaluated each minute after exposure to 5 microm epinephrine (or phenylephrine) alone or with the test drugs. Changes in the rate of phase 0 depolarization (Vmax) and the electrotonic spread of intracellular current were measured during exposure to epinephrine with octanol to evaluate the role of inhibition of active and passive (intercellular coupling) membrane properties in the transient depression of conduction velocity. Results Lidocaine (20 microm) and octanol (0.2 mm) potentiated alpha1-AR-induced conduction depression like halothane (0.4 mm), with maximum depression at 3-5 min of agonist exposure, no decrease of Vmax, and little accentuation at a rapid (250 vs. 150 pulses/min) stimulation rate. Thiopental (95 microm), propofol (50 microm), and verapamil (2 microm) similarly potentiated epinephrine responses, whereas etomidate (10 microm) did not. Between groups, the decrease of velocity induced by epinephrine in the presence of (10 microm) l-palmitoyl carnitine (-18%) was significantly greater than that resulting from epinephrine alone (-6%; 0.05 </= P </= 0.10). Current injection experiments were consistent with marked transient inhibition of cell-to-cell coupling correlating with alpha1-AR conduction depression in fibers exposed to octanol. Conclusions Anesthetic "sensitization" to the arrhythmogenic effects of catecholamines may be a special case of a more general phenomenon by which not only some anesthetics and antiarrhythmic drugs but also possible ischemic fatty acid metabolites potentiate conduction depression due to acute alpha1-AR-mediated cell-to-cell uncoupling.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals Ibudilast Mitigates Delayed Bone Healing Caused by Lipopolysaccharide by Altering Osteoblast and Osteoclast Activity

2021 ◽  
Vol 22 (3) ◽  
pp. 1169
Author(s):  
Yuhan Chang ◽  
Chih-Chien Hu ◽  
Ying-Yu Wu ◽  
Steve W. N. Ueng ◽  
Chih-Hsiang Chang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bone Formation ◽  
Cancellous Bone ◽  
Bone Healing ◽  
Bone Bridge ◽  
Cell Wall Components ◽  
Osteoclast Activity ◽  
Wall Components

Bacterial infection in orthopedic surgery is challenging because cell wall components released after bactericidal treatment can alter osteoblast and osteoclast activity and impair fracture stability. However, the precise effects and mechanisms whereby cell wall components impair bone healing are unclear. In this study, we characterized the effects of lipopolysaccharide (LPS) on bone healing and osteoclast and osteoblast activity in vitro and in vivo and evaluated the effects of ibudilast, an antagonist of toll-like receptor 4 (TLR4), on LPS-induced changes. In particular, micro-computed tomography was used to reconstruct femoral morphology and analyze callus bone content in a femoral defect mouse model. In the sham-treated group, significant bone bridge and cancellous bone formation were observed after surgery, however, LPS treatment delayed bone bridge and cancellous bone formation. LPS inhibited osteogenic factor-induced MC3T3-E1 cell differentiation, alkaline phosphatase (ALP) levels, calcium deposition, and osteopontin secretion and increased the activity of osteoclast-associated molecules, including cathepsin K and tartrate-resistant acid phosphatase in vitro. Finally, ibudilast blocked the LPS-induced inhibition of osteoblast activation and activation of osteoclast in vitro and attenuated LPS-induced delayed callus bone formation in vivo. Our results provide a basis for the development of a novel strategy for the treatment of bone infection.

Role of pili in adherence of Pseudomonas aeruginosa to mammalian buccal epithelial cells

1980 ◽  
Vol 29 (3) ◽  
pp. 1146-1151 ◽  
Author(s):  
D E Woods ◽  
D C Straus ◽  
W G Johanson ◽  
V K Berry ◽  
J A Bass
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Opportunistic Pathogen ◽  
In Vitro System ◽  
Heterologous Antiserum ◽  
Buccal Epithelial Cells ◽  
Serological Studies ◽  
Seriously Ill Patients

Adherence of Pseudomonas aeruginosa organisms to the upper respiratory epithelium of seriously ill patients in vitro is correlated with subsequent colonization of the respiratory tract by this opportunistic pathogen. The role of pili in the attachment to epithelial cells of P. aeruginosa was studied in an in vitro system employing human buccal epithelial cells and P. aeruginosa pretreated by various means. Pretreatment of the bacteria with proteases, heat, or Formalin caused a significant decrease in adherence. A decrease when compared with controls was also noted in the adherence of P. aeruginosa organisms to buccal epithelial cells preincubated with purified pili prepared from the strain used for adherence testing; however, pili prepared from a heterologous strain failed to block adherence. Similar results were obtained in serological studies when antisera to purified pili prepared from the strain used for adherence testing decreased adherence, whereas heterologous antiserum to pili did not decrease adherence. From these results it appears that pili mediate the adherence of P. aeruginosa organisms to human buccal epithelial cells.

Role of kallikrein-kinin system in pathogenesis of bacterial cell wall-induced inflammation

1991 ◽  
Vol 260 (2) ◽  
pp. G213-G219 ◽  
Author(s):  
R. A. DeLa Cadena ◽  
K. J. Laskin ◽  
R. A. Pixley ◽  
R. B. Sartor ◽  
J. H. Schwab ◽  
...  
Keyword(s):  
Cell Wall ◽  
Acute Phase ◽  
Bacterial Cell ◽  
Chronic Phase ◽  
Bacterial Cell Wall ◽  
Kinin System ◽  
Kallikrein Kinin System ◽  
Bacterial Products

The plasma kallikrein-kinin system is activated in Gram-negative sepsis and typhoid fever, two diseases in which bacterial products have been shown to initiate inflammation. Because a single intraperitoneal injection of bacterial cell wall peptidoglycan-polysaccharide polymers from group A steptococci (PG-APS) into a Lewis rat produces a syndrome of relapsing polyarthritis and anemia, we investigated changes in the role of the kallikrein-kinin system in this model of inflammation. Coagulation studies after injection of PG-APS revealed an immediate and persistent decrease in prekallikrein levels. High-molecular-weight kininogen levels decreased significantly during the acute phase and correlated with the severity of arthritis. Factor XI levels were decreased only during the acute phase. Antithrombin III levels remained unchanged, indicating that neither decreased hepatic synthesis nor disseminated intravascular coagulation caused the decreased plasma contact factors. Plasma T-kininogen (an acute phase protein) was significantly elevated during the chronic phase. PG-APS failed to activate the contact system in vitro. Thus the kallikrein-kinin system plays an important role in this experimental model of inflammation, suggesting that activation of this system may play a role in the pathogenesis of inflammatory bowel disease and rheumatoid arthritis in which bacterial products might be etiologically important.

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