scholarly journals The ADP Ribosyltransferase Domain of Pseudomonas aeruginosa ExoT Contributes to Its Biological Activities

2004 ◽  
Vol 72 (1) ◽  
pp. 546-558 ◽  
Author(s):  
L. Garrity-Ryan ◽  
S. Shafikhani ◽  
P. Balachandran ◽  
L. Nguyen ◽  
J. Oza ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Wound Repair ◽  
Biological Activities ◽  
Point Mutations ◽  
Residual Activity ◽  
Rho Family ◽  
Almost All ◽  
Adp Ribosyltransferase

ABSTRACT ExoT is a type III secreted effector protein found in almost all strains of Pseudomonas aeruginosa and is required for full virulence in an animal model of acute pneumonia. It is comprised of an N-terminal domain with GTPase activating protein (GAP) activity towards Rho family GTPases and a C-terminal ADP ribosyltransferase (ADPRT) domain with minimal activity towards a synthetic substrate in vitro. Consistent with its activity as a Rho family GTPase, ExoT has been shown to inhibit P. aeruginosa internalization into epithelial cells and macrophages, disrupt the actin cytoskeleton through a Rho-dependent pathway, and inhibit wound repair in a scrape model of injured epithelium. We have previously shown that mutation of the invariant arginine of the GAP domain to lysine (R149K) results in complete loss of GAP activity in vitro but only partially inhibits ExoT anti-internalization and cell rounding activity. We have constructed in-frame deletions and point mutations within the ADPRT domain in order to test whether this domain might account for the residual activity observed in ExoT GAP mutants. Deletion of a majority of the ADPRT domain (residues 234 to 438) or point mutations of the ADPRT catalytic site (residues 383 to 385) led to distinct changes in host cell morphology and substantially reduced the ability of ExoT to inhibit in vitro epithelial wound healing over a 24-h period. In contrast, only subtle effects on the efficiency of ExoT-induced bacterial internalization were observed in the ADPRT mutant forms. Expression of each domain individually in Saccharomyces cerevisiae was toxic, whereas expression of each of the catalytically inactive mutant domains was not. Collectively, these data demonstrate that the ADPRT domain of ExoT is active in vivo and contributes to the pathogenesis of P. aeruginosa infections.

Synthesis of Fragments of the Vasoactive Intestinal Peptide (VIP) and Analysis of Their Residual Biological Activities

1995 ◽  
Vol 60 (7) ◽  
pp. 1229-1235 ◽  
Author(s):  
Ivana Zoulíková ◽  
Ivan Svoboda ◽  
Jiří Velek ◽  
Václav Kašička ◽  
Jiřina Slaninová ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Residual Activity ◽  
Detailed Examination ◽  
Amino Acid Residues ◽  
Linear Peptide ◽  
Zone Electrophoresis ◽  
Capillary Zone

The vasoactive intestinal (poly)peptide (VIP) is a linear peptide containing 28 amino acid residues, whose primary structure indicates a low metabolic stability. The following VIP fragments, as potential metabolites, and their analogues were prepared by synthesis on a solid: [His(Dnp)1]VIP(1-10), VIP(11-14), [D-Arg12]VIP(11-14), [Lys(Pac)15,21,Arg20]VIP(15-22), and VIP(23-28). After purification, the peptides were characterized by amino acid analysis, mass spectrometry, RP HPLC, and capillary zone electrophoresis. In some tests, detailed examination of the biological activity of the substances in vivo and in vitro gave evidence of a low, residual activity of some fragments, viz. a depressoric activity in vivo for [His(Dnp)1]VIP(1-10) and a stimulating activity for the release of α-amylase in vitro and in vivo for [Lys(Pac)15,21,Arg20]VIP(15-22) and VIP(23-28).

scholarly journals Biological Characterization of Endotoxins Released from Antibiotic-Treated Pseudomonas aeruginosa and Escherichia coli

1998 ◽  
Vol 42 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Teruo Kirikae ◽  
Fumiko Kirikae ◽  
Shinji Saito ◽  
Kaoru Tominaga ◽  
Hirohi Tamura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Biological Activities ◽  
Polymyxin B ◽  
Mitogen Activated Protein Kinase ◽  
No Production ◽  
Endotoxic Activity

ABSTRACT The supernatants taken from Pseudomonas aeruginosa andEscherichia coli cultures in human sera or chemically defined M9 medium in the presence of ceftazidime (CAZ) contained high levels of endotoxin, while those taken from the same cultures in the presence of imipenem (IPM) yielded a very low level of endotoxin. The biological activities of endotoxin in the supernatants were compared with those of phenol water-extracted lipopolysaccharide (LPS). The endotoxin released from the organisms as a result of CAZ treatment (CAZ-released endotoxin) contained a large amount of protein. The protein, however, lacked endotoxic activity, since the endotoxin did not show any in vivo toxic effects in LPS-hyporesponsive C3H/HeJ mice sensitized with d-(+)-galactosamine (GalN) or any activation of C3H/HeJ mouse macrophages in vitro. The activities of CAZ- and IPM-released endotoxin (as assessed by a chromogenicLimulus test) were fundamentally the same as those ofP. aeruginosa LPS, since their regression lines were parallel. The CAZ-released endotoxin was similar to purified LPS with respect to the following biological activities in LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice: lethal toxicity in GalN-sensitized mice, in vitro induction of tumor necrosis factor- and NO production by macrophages, and mitogen-activated protein kinase activation in macrophages. The macrophage activation by CAZ-released endotoxin as well as LPS was mainly dependent on the presence of serum factor and CD14 antigen. Polymyxin B blocked the activity. These findings indicate that the endotoxic activity of CAZ-released endotoxin is due primarily to LPS (lipid A).

scholarly journals Effect of the Attenuating Deletion and of Sequence Alterations Evolving In Vivo on Simian Immunodeficiency Virus C8-Nef Function

1999 ◽  
Vol 73 (4) ◽  
pp. 2790-2797 ◽  
Author(s):  
Silke Carl ◽  
A. John Iafrate ◽  
Jacek Skowronski ◽  
Christiane Stahl-Hennig ◽  
Frank Kirchhoff
Keyword(s):  
Viral Replication ◽  
Simian Immunodeficiency Virus ◽  
Point Mutations ◽  
Residual Activity ◽  
Intermediate Phenotype ◽  
Cell Surface Expression ◽  
In Vitro Assays ◽  
Immunodeficiency Virus

ABSTRACT The simian immunodeficiency virus macC8 (SIVmacC8) variant has been used in a European Community Concerted Action project to study the efficacy and safety of live attenuated SIV vaccines in a large number of macaques. The attenuating deletion in the SIVmacC8nef-long terminal repeat region encompasses only 12 bp and is “repaired” in a subset of infected animals. It is unknown whether C8-Nef retains some activity. Since it seems important to use only well-characterized deletion mutants in live attenuated vaccine studies, we analyzed the relevance of the deletion, and the duplications and point mutations selected in infected macaques for Nef function in vitro. The deletion, affecting amino acids 143 to 146 (DMYL), resulted in a dramatic decrease in Nef stability and function. The initial 12-bp duplication resulted in efficient Nef expression and an intermediate phenotype in infectivity assays, but it did not significantly restore the ability of Nef to stimulate viral replication and to downmodulate CD4 and class I major histocompatibility complex cell surface expression. The additional substitutions however, which subsequently evolved in vivo, gradually restored these Nef functions. It was noteworthy that coinfection experiments in the T-lymphoid 221 cell line revealed that even SIVmac nef variants carrying the original 12-bp deletion readily outgrew an otherwise isogenic virus containing a 182-bp deletion in the nef gene. Thus, although C8-Nef is unstable and severely impaired in in vitro assays, it maintains some residual activity to stimulate viral replication.

scholarly journals Repurposing Anti-diabetic Drugs to Cripple Quorum Sensing in Pseudomonas aeruginosa

2020 ◽  
Vol 8 (9) ◽  
pp. 1285
Author(s):  
Wael A. H. Hegazy ◽  
Maan T. Khayat ◽  
Tarek S. Ibrahim ◽  
Majed S. Nassar ◽  
Muhammed A. Bakhrebah ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
In Silico Analysis ◽  
Resistance Mechanisms ◽  
Chemical Structures ◽  
Similar Chemical ◽  
Almost All ◽  
Encoding Genes

Pseudomonas aeruginosa is a significant human pathogen, it possesses almost all of the known antimicrobial resistance mechanisms. Quorum sensing (QS) is an intercellular communication system that orchestrates bacterial virulence and its targeting is an effective approach to diminish its pathogenesis. Repurposing of drugs is an advantageous strategy, in this study we aimed to repurpose the anti-diabetic drugs sitagliptin, metformin and vildagliptin as anti-QS in P. aeruginosa. The effects of sub-inhibitory concentrations of the tested drugs on the expression of QS-encoding genes and QS-regulated virulence factors were assessed. The protective activity of tested drugs on P. aeruginosa pathogenesis was evaluated in vivo on mice. In silico analysis was performed to evaluate the interference capabilities of the tested drugs on QS-receptors. Although the three drugs reduced the expression of QS-encoding genes, only sitagliptin inhibited the P. aeruginosa virulence in vitro and protected mice from it. In contrast, metformin showed significant in vitro anti-QS activities but failed to protect mice from P. aeruginosa. Vildagliptin did not show any in vitro or in vivo efficacy. Sitagliptin is a promising anti-QS agent because of its chemical nature that hindered QS-receptors. Moreover, it gives an insight to consider their similar chemical structures as anti-QS agents or even design new chemically similar anti-QS pharmacophores.

scholarly journals In Vitro and In Vivo Assessment of the Efficacy of Bromoageliferin, an Alkaloid Isolated from the Sponge Agelas dilatata, against Pseudomonas aeruginosa

Marine Drugs ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 326
Author(s):  
Dawrin Pech-Puch ◽  
Mar Pérez-Povedano ◽  
Marta Martinez-Guitian ◽  
Cristina Lasarte-Monterrubio ◽  
Juan Carlos Vázquez-Ucha ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carboxylic Acid ◽  
Galleria Mellonella ◽  
Biological Activities ◽  
Marine Sponges ◽  
In Vitro Assays ◽  
Significant Activity ◽  
Wide Range

The pyrrole-imidazoles, a group of alkaloids commonly found in marine sponges belonging to the genus Agelas, display a wide range of biological activities. Herein, we report the first chemical study of the secondary metabolites of the sponge A. dilatata from the coastal area of the Yucatan Peninsula (Mexico). In this study, we isolated eight known alkaloids from an organic extract of the sponge. We used NMR and MS analysis and comparison with existing databases to characterize the alkaloids: ageliferin (1), bromoageliferin (2), dibromoageliferin (3), sceptrin (4), nakamuric acid (5), 4-bromo-1H-pyrrole-2-carboxylic acid (6), 4,5-dibromopyrrole-2-carboxylic acid (7) and 3,7-dimethylisoguanine (8). We also evaluated, for the first time, the activity of these alkaloids against the most problematic multidrug-resistant (MDR) pathogens, i.e., the Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii. Bromoageliferin (2) displayed significant activity against P. aeruginosa. Comparison of the antibacterial activity of ageliferins 1–3 (of similar structure) against P. aeruginosa revealed some relationship between structure and activity. Furthermore, in in vitro assays, 2 inhibited growth and biofilm production in clinical strains of P. aeruginosa. Moreover, 2 increased the survival time in an in vivo Galleria mellonella model of infection. The findings confirm bromoageliferin (2) as a potential lead for designing new antibacterial drugs.

scholarly journals The Modern Use of an Ancient Plant: Exploring the Antioxidant and Nutraceutical Potential of the Maltese Mushroom (Cynomorium Coccineum L.)

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 289 ◽  
Author(s):  
Paolo Zucca ◽  
Sidonie Bellot ◽  
Antonio Rescigno
Keyword(s):  
North Africa ◽  
Biological Activities ◽  
Natural Substances ◽  
Cosmetic Formulations ◽  
Potential Reservoir ◽  
Tyrosinase Enzyme ◽  
Almost All ◽  
Effective Drugs

In the continuous scientific search for new safe and effective drugs, there has recently been a rediscovery of natural substances as a potential reservoir of innovative therapeutic solutions for human health, with the prospect of integrating with and sometimes replacing conventional drugs. Cynomorium coccineum subsp. coccineum is a holoparasitic plant well known in ethnopharmacology, although its current use as a curative remedy is reported only in some ethnic groups of North Africa and the Arabian Peninsula. Often known as ‘Maltese mushroom’ due to its unique appearance and the absence of chlorophyll, C. coccineum is present in almost all of the Mediterranean Basin. It is only recently that a few research groups have begun to look for confirmation of some of its traditional uses to highlight previously unknown biological activities. Here, we review the recent scientific findings on the plant’s phytochemistry and the most significant descriptions of some of its antioxidant and biological activities (antimicrobial, anticancer, pro-erectile, and anti-tyrosinase enzyme) both in vivo and in vitro. Some of these may be promising from the perspective of food and cosmetic formulations. The purpose of this review is to provide an initial impetus to those who, in the foreseeable future, will want to increase the knowledge and possible applications of this plant full of history, charm, and mystery.

scholarly journals Beneficial Biological Activities of Cinnamomum osmophloeum and Its Potential Use in the Alleviation of Oral Mucositis: A Systematic Review

Biomedicines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
Abu Bakar ◽  
Pin-Chuan Yao ◽  
Valendriyani Ningrum ◽  
Cheng-Tzu Liu ◽  
Shih-Chieh Lee
Keyword(s):  
Systematic Review ◽  
Oral Mucositis ◽  
Wound Repair ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
In Vivo Studies ◽  
Potential Use ◽  
Anti Inflammation

The aim of this review was to provide an updated overview of studies on the medical-biological activities of Cinnamomum osmophloeum (C. osmophloeum) in vitro and in vivo and the potential therapeutic use of natural agents prepared from this plant for the alleviation of oral mucositis (OM). Reported articles were collected using web search engine tools. The systematic review was organized according to the preferred reporting items for reviews and meta-analyses (PRISMA) statement. Additional sources were identified through cross-referencing to identify the potential use of C. osmophloeum in the alleviation of OM. The results disclosed that C. osmophloeum is comprised of bioactive ingredients that could act diversely as a reagent in anti-inflammation, antibacterial, antioxidant, anti-hyperglycemic, antidyslipidemia, anti-cancer, renal disease therapy and anti-hyperuricemia capacities. Recent studies revealed that the overall effects on anti-inflammation, wound repair, and the antibacterial and antioxidant activities of its constituents would act as a potential remedy for oral mucositis. Up-to-date in vitro and in vivo studies on the medical-biological activities of C. osmophloeum suggested that C. osmophloeum and its constituents could be promising remedies as adjuvants in OM therapy and warrant further investigation.

scholarly journals Can Polyphenols Inhibit Ferroptosis?

Antioxidants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 150
Author(s):  
Marija Lesjak ◽  
Nataša Simin ◽  
Surjit K. S. Srai
Keyword(s):  
Chronic Conditions ◽  
Higher Plants ◽  
Biological Activities ◽  
Lipid Peroxides ◽  
Great Expectations ◽  
Naturally Occurring ◽  
Polyphenol Intake ◽  
Almost All

Polyphenols, a diverse group of naturally occurring molecules commonly found in higher plants, have been heavily investigated over the last two decades due to their potent biological activities—among which the most important are their antioxidant, antimicrobial, anticancer, anti-inflammatory and neuroprotective activities. A common route of polyphenol intake in humans is through the diet. Since they are subjected to excessive metabolism in vivo it has been questioned whether their much-proven in vitro bioactivity could be translated to in vivo systems. Ferroptosis is a newly introduced, iron-dependent, regulated mode of oxidative cell death, characterized by increased lipid peroxidation and the accumulation of toxic lipid peroxides, which are considered to be toxic reactive oxygen species. There is a growing body of evidence that ferroptosis is involved in the development of almost all chronic diseases. Thus, ferroptosis is considered a new therapeutic target for offsetting many diseases, and researchers are putting great expectations on this field of research and medicine. The aim of this review is to critically analyse the potential of polyphenols to modulate ferroptosis and whether they can be considered promising compounds for the alleviation of chronic conditions.

scholarly journals Recent Advances in Cellulose-Based Structures as the Wound-Healing Biomaterials: A Clinically Oriented Review

2021 ◽  
Vol 11 (17) ◽  
pp. 7769
Author(s):  
Mohammad Foad Abazari ◽  
Shayan Gholizadeh ◽  
Shohreh Zare Karizi ◽  
Nazanin Hajati Birgani ◽  
Danya Abazari ◽  
...  
Keyword(s):  
Wound Healing ◽  
Wound Repair ◽  
Biological Activities ◽  
Healing Process ◽  
Bioactive Molecules ◽  
In Vivo Models ◽  
Pathogen Invasion ◽  
Wide Range

Application of wound-healing/dressing biomaterials is amongst the most promising approaches for wound repair through protection from pathogen invasion/contamination, maintaining moisture, absorbing exudates, modulating inflammation, and facilitating the healing process. A wide range of materials are used to fabricate wound-healing/dressing biomaterials. Active wound-healing/dressings are next-generation alternatives for passive biomaterials, which provide a physical barrier and induce different biological activities, such as antibacterial, antioxidant, and proliferative effects. Cellulose-based biomaterials are particularly promising due to their tunable physical, chemical, mechanical, and biological properties, accessibility, low cost, and biocompatibility. A thorough description and analysis of wound-healing/dressing structures fabricated from cellulose-based biomaterials is discussed in this review. We emphasize and highlight the fabrication methods, applied bioactive molecules, and discuss the obtained results from in vitro and in vivo models of cellulose-based wound-healing biomaterials. This review paper revealed that cellulose-based biomaterials have promising potential as the wound-dressing/healing materials and can be integrated with various bioactive agents. Overall, cellulose-based biomaterials are shown to be effective and sophisticated structures for delivery applications, safe and multi-customizable dressings, or grafts for wound-healing applications.

scholarly journals Modification of Ras in Eukaryotic Cells by Pseudomonas aeruginosa Exoenzyme S

1998 ◽  
Vol 66 (6) ◽  
pp. 2607-2613 ◽  
Author(s):  
Eileen M. McGuffie ◽  
Dara W. Frank ◽  
Timothy S. Vincent ◽  
Joan C. Olson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Exoenzyme S ◽  
Ras Family ◽  
Isogenic Mutant Strain ◽  
Related Proteins ◽  
Adp Ribosyltransferase

ABSTRACT Genetic and functional data suggest that Pseudomonas aeruginosa exoenzyme S (ExoS), an ADP-ribosyltransferase, is translocated into eukaryotic cells by a bacterial type III secretory mechanism activated by contact between bacteria and host cells. Although purified ExoS is not toxic to eukaryotic cells, ExoS-producing bacteria cause reduced proliferation and viability, possibly mediated by bacterially translocated ExoS. To investigate the activity of translocated ExoS, we examined in vivo modification of Ras, a preferred in vitro substrate. The ExoS-producing strain P. aeruginosa388 and an isogenic mutant strain, 388ΔexoS, which fails to produce ExoS, were cocultured with HT29 colon carcinoma cells. Ras was found to be ADP-ribosylated during coculture with 388 but not with 388ΔexoS, and Ras modification by 388 corresponded with reduction in HT29 cell DNA synthesis. Active translocation by bacteria was found to be required, since exogenous ExoS, alone or in the presence of 388ΔexoS, was unable to modify intracellular Ras. Other ExoS-producing strains caused modification of Ras, indicating that this is not a strain-specific event. ADP-ribosylation of Rap1, an additional Ras family substrate for ExoS in vitro, was not detectable in vivo under conditions sufficient for Ras modification, suggesting possible ExoS substrate preference among Ras-related proteins. These results confirm that intracellular Ras is modified by bacterially translocated ExoS and that the inhibition of target cell proliferation correlates with the efficiency of Ras modification.

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