Characterization of the Molecular Lipophilicity of Mycolactones A/B and C, Infectious Factors of Mycobacterium ulcerans Agent of Buruli Ulcer

The work was undertaken as part of the Buruli ulcer control program. It is particularly about the determination of the lipophilicity of mycolactones A/B and C, infectious factors of Mycobacterium ulcerans, the agent of Buruli ulcer. The REKKER method and some free software such as MOLINSPIRATION, ACD/ChemSketch and EPIWED were used for the determination of the lipophilicity of mycolactones A/B and C. Very high logP values were found and respectively ranged from 12.11 to 11.41 for mycolactone A/B and 11.69 to 11.58 for mycolactone C. These values obtained from this coefficient, show that mycolactones A/B and C are naturally lipophilic and that actually reflects their effective presence in the subcutaneous fat of the infected area. These results are very encouraging and promising. They are key factors for a better understanding of the biological activities of the two mycolactones and pave the way for the proposal of a mechanism to annihilate their destructive effects.

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Molecular and epidemiological characterization of recurrent Mycobacterium ulcerans infections in Benin

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0010053 ◽

2021 ◽

Vol 15 (12) ◽

pp. e0010053

Author(s):

Ronald Gnimavo ◽

Alban Besnard ◽

Horace Degnonvi ◽

Juliana Pipoli Da Fonseca ◽

Marie Kempf ◽

...

Keyword(s):

Random Distribution ◽

Buruli Ulcer ◽

Mycobacterium Ulcerans ◽

Neglected Tropical Disease ◽

Contaminated Water ◽

Ulcer Recurrence ◽

Paradoxical Reaction ◽

Environmental Mycobacterium ◽

Epidemiological Characterization

Background Buruli ulcer is a neglected tropical disease caused by Mycobacterium ulcerans, an environmental mycobacterium. Although transmission of M. ulcerans remains poorly understood, the main identified risk factor for acquiring Buruli ulcer is living in proximity of potentially contaminated water sources. Knowledge about the clinical features of Buruli ulcer and its physiopathology is increasing, but little is known about recurrence due to reinfection. Methodology/Principal findings We describe two patients with Buruli ulcer recurrence due to reinfection with M. ulcerans, as demonstrated by comparisons of DNA from the strains isolated at the time of the first diagnosis and at recurrence. Based on the spatial distribution of M. ulcerans genotypes in this region and a detailed study of the behavior of these two patients with respect to sources of water as well as water bodies and streams, we formulated hypotheses concerning the sites at which they may have been contaminated. Conclusions/Significance Second episodes of Buruli ulcer may occur through reinfection, relapse or a paradoxical reaction. We formally demonstrated that the recurrence in these two patients was due to reinfection. Based on the sites at which the patients reported engaging in activities relating to water, we were able to identify possible sites of contamination. Our findings indicate that the non-random distribution of M. ulcerans genotypes in this region may provide useful information about activities at risk.

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Molecular characterization of Mycobacterium ulcerans DNA gyrase and identification of mutations reduced susceptibility against quinolones in vitro

10.1101/2021.09.29.462499 ◽

2021 ◽

Author(s):

Hyun Kim ◽

Shigtarou Mori ◽

Tsuyoshi Kenri ◽

Yasuhiko Suzuki

Keyword(s):

Buruli Ulcer ◽

Dna Gyrase ◽

Resistance Mechanisms ◽

Docking Studies ◽

Mycobacterium Ulcerans ◽

Amino Acid Residues ◽

Wild Type Enzyme ◽

Ulcer Disease

ABSTRACTBuruli ulcer disease is a neglected necrotizing and disabling cutaneous tropical illness caused by Mycobacterium ulcerans (Mul). Fluoroquinolone (FQ), used in the treatment of this disease, has been known to act by inhibiting the enzymatic activities of DNA gyrase; however, the detailed molecular basis of these characteristics and the FQ resistance mechanisms in Mul remains unknown. This study investigated the detailed molecular mechanism of Mul DNA gyrase and the contribution of FQ resistance in vitro using recombinant proteins from the Mul subsp. shinshuense and Agy99 strains with reduced sensitivity to FQs. The IC50 of FQs against Ala91Vla and Asp95Gly mutants of Mul shinshuense and Agy99 GyrA subunits were 3.7- to 42.0-fold higher than those against wild-type enzyme. Similarly, the CC25 was 10- to 210-fold higher than those for the WT enzyme. Furthermore, the interaction between the amino acid residues of WT/mutant Mul DNA gyrase and FQ side chains was assessed via molecular docking studies. This is the first detailed study showing the contribution of Mul DNA GyrA subunit mutations to reduce the susceptibility against FQs.

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Identification of P218 as a Potent Inhibitor of Mycobacteria Ulcerans DHFR

10.26434/chemrxiv.12899420.v1 ◽

2020 ◽

Author(s):

Gustavo Pelicioli Riboldi ◽

Rachael Zigweid ◽

Peter J. Myler ◽

Stephen J. Mayclin ◽

Rafael Counago ◽

...

Keyword(s):

Chronic Disease ◽

Side Effects ◽

Dihydrofolate Reductase ◽

De Novo ◽

Potent Inhibitor ◽

Critical Role ◽

Buruli Ulcer ◽

Mycobacterium Ulcerans ◽

De Novo Biosynthesis

Mycobacterium ulcerans is the causative agent of Buruli ulcer, a debilitating chronic disease that mainly affects the skin. Current treatments for Buruli ulcer are efficacious, but rely on the use of antibiotics with severe side effects. The enzyme dihydrofolate reductase (DHFR) plays a critical role in the de novo biosynthesis of folate species and is a validated target for several antimicrobials. Here we describe the biochemical and structural characterization of M. ulcerans DHFR and identified P218, a safe antifolate compound in clinical evaluation for malaria, as a potent inhibitor of this enzyme. We expect our results to advance M. ulcerans DHFR as a target for future structure-based drug discovery campaigns.

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Evaluation of Buruli Ulcer Disease Surveillance System in the Ga West Municipality, Ghana, 2011–2015

Journal of Tropical Medicine ◽

10.1155/2019/4721236 ◽

2019 ◽

Vol 2019 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

Tanko Rufai ◽

Enoch Aninagyei ◽

Samuel Oko Sackey ◽

Ernest Kenu ◽

Edwin Andrew Afari

Keyword(s):

Surveillance System ◽

Disease Surveillance ◽

Neglected Tropical Diseases ◽

Buruli Ulcer ◽

Control Program ◽

Mycobacterium Ulcerans ◽

Ulcer Disease ◽

Disease Surveillance System ◽

Key Stakeholders ◽

Control And Prevention

Background. Buruli ulcer (BU) is one of the most neglected tropical diseases caused by Mycobacterium ulcerans. M. ulcerans infection may manifest initially as a pre-ulcerative nodule, a plaque, or oedema which breaks down to form characteristic ulcers with undermined edges. The Ga West Municipality is an endemic area for Buruli ulcer, and we evaluated the BU surveillance system to determine whether the system is meeting its objectives and to assess its attributes. Materials and Methods. We used a checklist based on Centers for Disease Control and Prevention (CDC) updated surveillance evaluation guidelines, 2006. We reviewed records and dataset on Buruli ulcer for the period 2011–2015. The evaluation was carried out at the national, regional, district, and community levels using the Ga West Municipality of the Greater Accra Region as a study site. Interviews with key stakeholders at the various levels were done using an interview guide, and observations were done with a checklist. Data were entered and analyzed using Epi info 7. Results. A total of 594 cases of Buruli ulcer were reported from 2011 to 2015 in Ga West. The number of confirmed cases decreased from 109 in 2011 to 17 in 2015. The system was useful, fairly simple, flexible, representative, and fairly acceptable. The system was sensitive with a PVP of 45.3%. Although the data quality was good with 85% of case report forms completed, there was under-reporting (3.6%), some discrepancies of data at the district, regional, and national levels. The system was moderately stable, and timeliness of reporting was 30.7%. Conclusion. The Buruli ulcer surveillance system is meeting its set objectives, and the data generated are used to reliably describe the epidemiologic situation and evaluate the results for actions and plan future interventions. There is a need for timely submission of data. We recommend that the National Buruli Ulcer Control Program (NBUCP) provides logistical support to treatment centres.

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Beninese Medicinal Plants as a Source of Antimycobacterial Agents: Bioguided Fractionation andIn VitroActivity of Alkaloids Isolated fromHolarrhena floribundaUsed in Traditional Treatment of Buruli Ulcer

BioMed Research International ◽

10.1155/2015/835767 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Achille Yemoa ◽

Joachim Gbenou ◽

Dissou Affolabi ◽

Mansourou Moudachirou ◽

André Bigot ◽

...

Keyword(s):

Buruli Ulcer ◽

Cost Effective ◽

Antimycobacterial Activity ◽

Mycobacterium Ulcerans ◽

Traditional Treatment ◽

Aerial Parts ◽

Antimycobacterial Agents ◽

Pharmacologically Active ◽

Hydroethanolic Extract

Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems that are involved in diagnosing the disease and treating patients. Research is needed to find cost-effective therapies for this costly disease. Plants have always been an important source of new pharmacologically active molecules. Consequently we decided to undertake the study of plants used in traditional treatment of BU in Benin and investigate their antimycobacterial activity as well as their chemical composition. Extracts from forty-four (44) plant species were selected on account of reported traditional uses for the treatment of BU in Benin and were assayed for antimycobacterial activities. Crude hydroethanolic extract from aerial parts ofHolarrhena floribunda(G. Don) T. Durand and Schinz was found to have significant antimycobacterial activity againstM.ulcerans(MIC = 125 µg/mL). We describe here the identification of four steroidal alkaloids fromMycobacterium ulceransgrowth-inhibiting fractions of the alkaloidal extract of the aerial parts ofHolarrhena floribunda. Holadysamine was purified in sufficient amount to allow the determination of its MCI (=50 µg/mL). These results give some support to the use of this plant in traditional medicine.

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Characterization of Polyphenols and Mineral Contents in Three Medicinal Weeds

European Journal of Medicinal Plants ◽

10.9734/ejmp/2019/v28i330137 ◽

2019 ◽

pp. 1-8

Author(s):

Yaman Kumar Sahu ◽

Khageshwar Singh Patel ◽

Pablo Martín-Ramos ◽

Erick K. Towett

Keyword(s):

Spectrophotometric Determination ◽

Aluminum Chloride ◽

Total Concentration ◽

Mineral Contents ◽

Total Polyphenol ◽

X Ray ◽

High K ◽

Very High

Aims: Common weeds Rorippa palustris (L.) Besser, Euphorbia rothiana Spreng. and Schoenoplectiella articulata (L.) Lye are used for food, medicinal, green biofertilizer and biosorbent applications. In this work, their polyphenol and mineral contents have been characterized. Methodology: Samples from aforementioned three plants were manually collected in Raipur city (CG, India) and processed for the analyses. Folin-Ciocalteu and aluminum chloride were used for the spectrophotometric determination of polyphenols. The mineral contents were quantified by X-ray fluorescence. Results: The total concentration of 20 elements (viz. P, S, Cl, As, Se, K, Rb, Mg, Ca, Sr, Ba, Al, Ti, Cr, Mn, Fe, Co, Zn, Mo and Pb), total polyphenol and flavonoid contents in the leaves ranged from 46372 to 71501, from 47877 to 73791 and from 1950 to 9400 mg/kg, respectively. Remarkable concentrations of several nutrients (P, S, Cl, K, Mg, Ca and Fe) were observed. Conclusion: The biomass from medicinal weeds R. palustris, E. rothiana and S. articulata featured very high K, Ca and Fe contents. Other nutrients (polyphenols, flavonoids, P, S, Cl and Mg) were identified at moderate levels. These species may hold promise as bioindicators.

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Very-high-field n.m.r. studies of bovine lung heparan sulphate tetrasaccharides produced by nitrous acid deaminative cleavage. Determination of saccharide sequence, uronate composition and degrees of sulphation

Biochemical Journal ◽

10.1042/bj2230495 ◽

1984 ◽

Vol 223 (2) ◽

pp. 495-505 ◽

Cited By ~ 14

Author(s):

P N Sanderson ◽

T N Huckerby ◽

I A Nieduszynski

Keyword(s):

Nitrous Acid ◽

High Field ◽

General Structure ◽

Heparan Sulphate ◽

Gel Filtration ◽

Exchange Chromatography ◽

Very High ◽

Specific Sequences

Tetrasaccharides with the general structure UA-GlcNAc-GlcUA-aManOH (where UA represents uronate, GlcNAc N-acetylglucosamine, GlcUA glucuronate and aManOH anhydromannitol) were prepared from low-sulphated heparan sulphates of bovine lung origin by complete nitrous acid deaminative cleavage followed by reduction and fractionated by gel filtration. Ion-exchange chromatography of the tetrasaccharides yielded three major fractions in approximate yields of 37%, 45% and 14%. These were shown to be non-, mono- and di-sulphated respectively. Complete structural characterization of the tetrasaccharide fractions by quantitative high-field n.m.r. spectroscopy showed that each fraction contained only two discrete species and led to the following observations. (1) All of the uronate residues in the tetrasaccharides (and in larger oligosaccharides) are unsulphated, and hence sulphated iduronate [IdUA(2SO3)] must occur exclusively within -GlcNSO3-IdUA(2SO3)-GlcNSO3- sequences (where GlcNSO3 represents N-sulpho-glucosamine) in the parent polymers. (2) The GlcNAc residues in the tetrasaccharides are more highly C-6-O-sulphated than are the aManOH residues, and furthermore sulphation on the aManOH appears to occur only where the GlcNAc is also sulphated. (3) Where the GlcNAc is C-6-O-sulphated, iduronate is the major non-reducing terminal residue, whereas glucuronate predominates in this position if the GlcNAc is unsulphated. The quantitative data obtained are used to determine the degree of C-6-O-sulphation of glucosamine residues in specific sequences within the parent heparan sulphates.

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Plasmin Digestion of factor VIII: Characterization of the Breakdown Products with Respect to Antigenicity and von Willebrand Activity

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648664 ◽

1978 ◽

Vol 40 (02) ◽

pp. 302-315 ◽

Cited By ~ 11

Author(s):

J A Guisasola ◽

C G Cockburn ◽

R M Hardisty

Keyword(s):

Factor Viii ◽

Biological Activities ◽

Molecular Size ◽

Progressive Increase ◽

Gel Chromatography ◽

Molecular Weights ◽

Von Willebrand ◽

Ristocetin Cofactor

SummaryHighly purified factor VIII was incubated for up to 24 hours in the presence of plasmin, and the biological activities and peptide structure of the digestion products determined at intervals. Procoagulant activity (VIIIC) was rapidly lost, but 17-32% of the initial ristocetin cofactor (VIIIR: WF) activity remained after 24 hours. Immunoelectrophoresis showed a progressive increase in rocket height and a concomitant increase in electrophoretic mobility of the factor-VIII-related antigen (VIIIR: AG). Crossed immunoelectrophoresis of the 24- hour digest showed three distinct precipitin arcs, of which the major one, with intermediate anodal mobility, gave reactions of non-identity with the other two. On sepharose gel chromatography the 24-hour digest gave three peaks: peak II contained about 80% of the residual VIIIR: WF and resolved on SDS-polyacrylamide gels into a series of peptides with apparent molecular weights between 125,000 and 185,000; these were reduced by mercaptoethanol to fragments of 15,000-80,000 daltons, a 65,000 dalton fragment being particularly strongly PAS positive. We conclude that large molecular size is not a prerequisite for VIIIR :WF activity, and that the presence of factor-VIII breakdown products may be a cause of misleading results in the determination of VIIIR:AG by immunoelectrophoresis.

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Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

Minerals ◽

10.3390/min11080803 ◽

2021 ◽

Vol 11 (8) ◽

pp. 803

Author(s):

Carlos Hoffmann Sampaio ◽

Bogdan Cazacliu ◽

Weslei Ambrós ◽

Márcio Kronbauer ◽

Rejane Tubino ◽

...

Keyword(s):

High Strength Concrete ◽

Coarse Aggregate ◽

Size Range ◽

High Strength ◽

Gravity Concentration ◽

Strength Concrete ◽

Ordinary Concrete ◽

Very High

This paper presents a physical characterization for the recycling into new concretes of three comminuted concretes: C16/20 (“ordinary concrete”), C50/60 (“high strength concrete”), and C70/85 (“very high strength concrete”). The top size of the crushed concretes was 19.1 mm and the size range was 4.75 to 19.1 mm. The characterization was carried out with coarse aggregate liberation, to be prepared and concentrated in a gravity concentration process. The density distribution of the coarse aggregate, cement paste, and sand was carried out in different size ranges (4.75/19.1 mm; 4.75/8.0 mm; 8.0/12.5 mm; and 12.5/19.1 mm) for the three concretes studied. The form factor of the samples, as well as the porosity determination of particles in different density ranges, are presented. The obtained results indicate that the coarse aggregate liberation was more intensive for the low resistance concrete (C16/20), but a reasonable coarse aggregate recovery is possible for all concretes.

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