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Mukomura J, Nonaka H, Sato H, Kishimoto M, Arai M, Kotoku N. Anti-Mycobacterial N-(2-Arylethyl)quinolin-3-amines Inspired by Marine Sponge-Derived Alkaloid. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248701. [PMID: 36557834 PMCID: PMC9781020 DOI: 10.3390/molecules27248701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/03/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
The synthesis and evaluation of simplified analogs of marine sponge-derived alkaloid 3-(phenethylamino)demethyl(oxy)aaptamine were performed to develop novel anti-mycobacterial substances. Ring truncation of the tricyclic benzo[de][1,6]-naphthyridine skeleton effectively weakened the cytotoxicity of the natural product, and the resulting AC-ring analog exhibited good anti-mycobacterial activity. A structure-activity relationship (SAR) study, synthesizing and evaluating some analogs, demonstrated the specificity and importance of the N-(2-arylethyl)quinolin-3-amine skeleton as a promising scaffold for anti-mycobacterial lead compounds.
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Affiliation(s)
- Junya Mukomura
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan
| | - Hiroki Nonaka
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiromasa Sato
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Maho Kishimoto
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan
| | - Masayoshi Arai
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Naoyuki Kotoku
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Correspondence: ; Tel.: +81-77-561-4920
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2
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Alvarez AH. Revisiting tuberculosis screening: An insight to complementary diagnosis and prospective molecular approaches for the recognition of the dormant TB infection in human and cattle hosts. Microbiol Res 2021; 252:126853. [PMID: 34536677 DOI: 10.1016/j.micres.2021.126853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/21/2021] [Accepted: 08/22/2021] [Indexed: 12/17/2022]
Abstract
Tuberculosis (TB) is defined as a chronic infection in both human and cattle hosts and many subclinical cases remain undetected. After the pathogen is inhaled by a host, phagocyted bacilli can persist inside macrophages surviving intracellularly. Hosts develop granulomatous lesions in the lungs or lymph nodes, limiting infection. However, bacilli become persister cells. Immunological diagnosis of TB is performed basically by routine tuberculin skin test (TST), and in some cases, by ancillary interferon-gamma release assay (IGRA). The concept of human latent TB infection (LTBI) by M. tuberculosis is recognized in cohorts without symptoms by routine clinical diagnostic tests, and nowadays IGRA tests are used to confirm LTBI with either active or latent specific antigens of M. tuberculosis. On the other hand, dormant infection in cattle by M. bovis has not been described by TST or IGRA testing as complications occur by cross-reactive immune responses to homolog antigens of environmental mycobacteria or a false-negative test by anergic states of a wained bovine immunity, evidencing the need for deciphering more specific biomarkers by new-generation platforms of analysis for detection of M. bovis dormant infection. The study and description of bovine latent TB infection (boLTBI) would permit the recognition of hidden animal infection with an increase in the sensitivity of routine tests for an accurate estimation of infected dairy cattle. Evidence of immunological and experimental analysis of LTBI should be taken into account to improve the study and the description of the still neglected boLTBI.
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Affiliation(s)
- Angel H Alvarez
- Centro de Investigación y Asistencia en Tecnología y diseño del Estado de Jalisco A.C. (CIATEJ), Consejo Nacional de Ciencia y Tecnología (CONACYT), Av. Normalistas 800 C.P. 44270, Guadalajara, Jalisco, Mexico.
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3
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Li Y, Sharma MR, Koripella RK, Banavali NK, Agrawal RK, Ojha AK. Ribosome hibernation: a new molecular framework for targeting nonreplicating persisters of mycobacteria. MICROBIOLOGY-SGM 2021; 167. [PMID: 33555244 DOI: 10.1099/mic.0.001035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Treatment of tuberculosis requires a multi-drug regimen administered for at least 6 months. The long-term chemotherapy is attributed in part to a minor subpopulation of nonreplicating Mycobacterium tuberculosis cells that exhibit phenotypic tolerance to antibiotics. The origins of these cells in infected hosts remain unclear. Here we discuss some recent evidence supporting the hypothesis that hibernation of ribosomes in M. tuberculosis, induced by zinc starvation, could be one of the primary mechanisms driving the development of nonreplicating persisters in hosts. We further analyse inconsistencies in previously reported studies to clarify the molecular principles underlying mycobacterial ribosome hibernation.
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Affiliation(s)
- Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Nilesh K Banavali
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA.,Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
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Zhang XH, Ahmad W, Zhu XY, Chen J, Austin B. Viable but nonculturable bacteria and their resuscitation: implications for cultivating uncultured marine microorganisms. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:189-203. [PMID: 37073345 PMCID: PMC10077291 DOI: 10.1007/s42995-020-00041-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 03/25/2020] [Indexed: 05/03/2023]
Abstract
Culturing has been the cornerstone of microbiology since Robert Koch first successfully cultured bacteria in the late nineteenth century. However, even today, the majority of microorganisms in the marine environment remain uncultivated. There are various explanations for the inability to culture bacteria in the laboratory, including lack of essential nutrients, osmotic support or incubation conditions, low growth rate, development of micro-colonies, and the presence of senescent or viable but nonculturable (VBNC) cells. In the marine environment, many bacteria have been associated with dormancy, as typified by the VBNC state. VBNC refers to a state where bacteria are metabolically active, but are no longer culturable on routine growth media. It is apparently a unique survival strategy that has been adopted by many microorganisms in response to harsh environmental conditions and the bacterial cells in the VBNC state may regain culturability under favorable conditions. The resuscitation of VBNC cells may well be an important way to cultivate the otherwise uncultured microorganisms in marine environments. Many resuscitation stimuli that promote the restoration of culturability have so far been identified; these include sodium pyruvate, quorum sensing autoinducers, resuscitation-promoting factors Rpfs and YeaZ, and catalase. In this review, we focus on the issues associated with bacterial culturability, the diversity of bacteria entering the VBNC state, mechanisms of induction into the VBNC state, resuscitation factors of VBNC cells and implications of VBNC resuscitation stimuli for cultivating these otherwise uncultured microorganisms. Bringing important microorganisms into culture is still important in the era of high-throughput sequencing as their ecological functions in the marine environment can often only be known through isolation and cultivation.
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Affiliation(s)
- Xiao-Hua Zhang
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071 China
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266100 China
| | - Waqar Ahmad
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Xiao-Yu Zhu
- College of Marine Life Sciences and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050 China
| | - Brian Austin
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA Scotland, UK
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5
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Rather MA, Bhat ZS, Lone AM, Maqbool M, Bhat BA, Ahmad Z. In vitro potency of 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione against drug-resistant and non-replicating persisters of Mycobacterium tuberculosis. J Glob Antimicrob Resist 2021; 25:202-208. [PMID: 33789204 DOI: 10.1016/j.jgar.2021.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 12/02/2020] [Accepted: 03/14/2021] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES New antituberculosis agents active against drug-resistant and non-replicating tubercle bacilli are required. We evaluated a previously identified hit, 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione (PAMCHD), against several clinical Mycobacterium tuberculosis isolates, including multidrug-resistant (MDR) strains and non-replicating drug-tolerant persisters of M. tuberculosis H37Rv. METHODS PAMCHD's potential against drug-resistant M. tuberculosis was investigated by broth microdilution. CFU enumeration was performed to determine PAMCHD's activity against five types of dormant bacilli. RESULTS No significant differences in MICs of PAMCHD were observed against M. tuberculosis H37Rv (2.5-5 µg/mL) and eight drug-susceptible strains (1.25-5 µg/mL) as well as drug-resistant strains including six isoniazid (INH)-resistant (2.5-10 µg/mL), one INH + ethambutol (EMB)-resistant (5 µg/mL), one rifampicin (RIF) + EMB-resistant (5 µg/mL) and three MDR (2.5-10 µg/mL) strains. Thus, PAMCHD maintains activity against all kinds of clinical strains, especially MDR. Regarding drug-tolerant persisters, INH and RIF killed, respectively, 0.5 and 5.0 log10 CFU of non-replicating persisters developed by hypoxia and 1.5 and 2.5 log10 CFU developed by nutrient starvation at 64 × of their respective MIC against actively dividing cultures. In contrast, PAMCHD sterilised persister cultures developed by hypoxia (killed 6.5 log10 CFU) or starvation (killed 7.5 log10 CFU). PAMCHD sterilised RIF-tolerant (tolerance level up to 100 µg/mL of RIF) 100-day-old static persisters at 64 × MIC, while moxifloxacin killed only 1.0 log10 CFU of these persisters at 64 × MIC. CONCLUSION PAMCHD offers significant potential against MDR-TB and exhibits notable potency against non-replicating drug-tolerant M. tuberculosis persisters. These findings warrant further studies of PAMCHD for further anti-TB drug development.
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Affiliation(s)
- Muzafar Ahmad Rather
- Clinical Microbiology and PK/PD Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India
| | - Zubair Shanib Bhat
- Clinical Microbiology and PK/PD Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India; Academy of Scientific and Innovative Research, CSIR - Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi 180001, Jammu & Kashmir, India
| | - Ali Mohd Lone
- Medicinal Chemistry Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India
| | - Mubashir Maqbool
- Clinical Microbiology and PK/PD Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India
| | - Bilal Ahmad Bhat
- Medicinal Chemistry Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India
| | - Zahoor Ahmad
- Clinical Microbiology and PK/PD Division, CSIR - Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, Jammu & Kashmir, India; Academy of Scientific and Innovative Research, CSIR - Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi 180001, Jammu & Kashmir, India.
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6
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Sarathy JP, Dartois V. Caseum: a Niche for Mycobacterium tuberculosis Drug-Tolerant Persisters. Clin Microbiol Rev 2020; 33:e00159-19. [PMID: 32238365 PMCID: PMC7117546 DOI: 10.1128/cmr.00159-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Caseum, the central necrotic material of tuberculous lesions, is a reservoir of drug-recalcitrant persisting mycobacteria. Caseum is found in closed nodules and in open cavities connecting with an airway. Several commonly accepted characteristics of caseum were established during the preantibiotic era, when autopsies of deceased tuberculosis (TB) patients were common but methodologies were limited. These pioneering studies generated concepts such as acidic pH, low oxygen tension, and paucity of nutrients being the drivers of nonreplication and persistence in caseum. Here we review widely accepted beliefs about the caseum-specific stress factors thought to trigger the shift of Mycobacterium tuberculosis to drug tolerance. Our current state of knowledge reveals that M. tuberculosis is faced with a lipid-rich diet rather than nutrient deprivation in caseum. Variable caseum pH is seen across lesions, possibly transiently acidic in young lesions but overall near neutral in most mature lesions. Oxygen tension is low in the avascular caseum of closed nodules and high at the cavity surface, and a gradient of decreasing oxygen tension likely forms toward the cavity wall. Since caseum is largely made of infected and necrotized macrophages filled with lipid droplets, the microenvironmental conditions encountered by M. tuberculosis in foamy macrophages and in caseum bear many similarities. While there remain a few knowledge gaps, these findings constitute a solid starting point to develop high-throughput drug discovery assays that combine the right balance of oxygen tension, pH, lipid abundance, and lipid species to model the profound drug tolerance of M. tuberculosis in caseum.
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Affiliation(s)
- Jansy P Sarathy
- Center for Discovery and Innovation, Hackensack Meridian School of Medicine at Seton Hall University, Nutley, New Jersey, USA
| | - Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian School of Medicine at Seton Hall University, Nutley, New Jersey, USA
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7
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Sumii Y, Kotoku N, Han C, Kamiya K, Setiawan A, Vilchèze C, Jacobs WR, Arai M. 3-(Phenethylamino)demethyl(oxy)aaptamine as an anti-dormant mycobacterial substance: Isolation, evaluation and total synthesis. Tetrahedron Lett 2020; 61. [PMID: 32577043 DOI: 10.1016/j.tetlet.2020.151924] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
3-(Phenethylamino)demethyl(oxy)aaptamine (1) was re-discovered from the marine sponge of Aaptos sp. as an anti-dormant mycobacterial substance through the bioassay-guided separation. Compound 1 showed potent anti-microbial activity against Mycobacterium bovis BCG with a minimum inhibitory concentration of 0.75 µg/mL under both aerobic conditions and hypoxic conditions inducing dormant state. Compound 1 was also effective against pathogenic M. tuberculosis strains including clinical multidrug-resistant strains. Furthermore, the successful total syntheses of 1 and its analog 3-aminodemethyl(oxy)aaptamine (2) afford sufficient quantities for further biological studies.
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Affiliation(s)
- Yuji Sumii
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.,Present affiliation: Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Naoyuki Kotoku
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.,Present affiliation: College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Chisu Han
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Kentaro Kamiya
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Andi Setiawan
- Department of Chemistry, Faculty of Science, Lampung University, Jl. Prof. Dr. Sumantri Brodjonegoro No. 1, Bandar Lampung 35145, Indonesia
| | - Catherine Vilchèze
- Albert Einstein College of Medicine; 1301 Morris Park Avenue, Bronx, New York 10461, U.S.A
| | - William R Jacobs
- Albert Einstein College of Medicine; 1301 Morris Park Avenue, Bronx, New York 10461, U.S.A
| | - Masayoshi Arai
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
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8
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Yam YK, Alvarez N, Go ML, Dick T. Extreme Drug Tolerance of Mycobacterium abscessus "Persisters". Front Microbiol 2020; 11:359. [PMID: 32194537 PMCID: PMC7064438 DOI: 10.3389/fmicb.2020.00359] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/18/2020] [Indexed: 01/25/2023] Open
Abstract
Persistence of infection despite extensive chemotherapy with antibiotics displaying low MICs is a hallmark of lung disease caused by Mycobacterium abscessus (Mab). Thus, the classical MIC assay is a poor predictor of clinical outcome. Discovery of more efficacious antibiotics requires more predictive in vitro potency assays. As a mycobacterium, Mab is an obligate aerobe and a chemo-organo-heterotroph – it requires oxygen and organic carbon sources for growth. However, bacteria growing in patients can encounter micro-environmental conditions that are different from aerated nutrient-rich broth used to grow planktonic cultures for MIC assays. These in vivo conditions may include oxygen and nutrient limitation which should arrest growth. Furthermore, Mab was shown to grow as biofilms in vivo. Here, we show Mab Bamboo, a clinical isolate we use for Mab drug discovery, can survive oxygen deprivation and nutrient starvation for extended periods of time in non-replicating states and developed an in vitro model where the bacterium grows as biofilm. Using these culture models, we show that non-replicating or biofilm-growing bacteria display tolerance to clinically used anti-Mab antibiotics, consistent with the observed persistence of infection in patients. To demonstrate the utility of the developed “persister” assays for drug discovery, we determined the effect of novel agents targeting membrane functions against these physiological forms of the bacterium and find that these compounds show “anti-persister” activity. In conclusion, we developed in vitro “persister” assays to fill an assay gap in Mab drug discovery compound progression and to enable identification of novel lead compounds showing “anti-persister” activity.
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Affiliation(s)
- Yee-Kuen Yam
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States.,Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Nadine Alvarez
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
| | - Mei-Lin Go
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States.,Department of Medical Sciences, Hackensack Meridian School of Medicine at Seton Hall University, Nutley, NJ, United States
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Biofilms of Mycobacterium abscessus Complex Can Be Sensitized to Antibiotics by Disaggregation and Oxygenation. Antimicrob Agents Chemother 2020; 64:AAC.01212-19. [PMID: 31740557 DOI: 10.1128/aac.01212-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/03/2019] [Indexed: 12/25/2022] Open
Abstract
Pulmonary infection with the multidrug-resistant Mycobacterium abscessus complex (MABSC) is difficult to treat in individuals with cystic fibrosis (CF). MABSC grows as biofilm aggregates in CF patient lungs, which are known to have anaerobic niches. How aggregation and anoxic conditions affect antibiotic tolerance is not well understood. We sought to determine whether disaggregation and oxygen availability sensitize MABSC isolates to recommended antibiotics. We tested the susceptibilities of 33 isolates from 22 CF patients with MABSC infection and a reference strain to the following antibiotics: amikacin, azithromycin, cefoxitin, ciprofloxacin, clarithromycin, imipenem, kanamycin, linezolid, moxifloxacin, rifampin, tigecycline, and sulfamethoxazole-trimethoprim. Isolates were grown in Mueller-Hinton broth with and without the disaggregating detergent Tween 80 (5%). Time-kill curves at days 1 and 3 were generated for oxic and anoxic amikacin treatment in 4-fold dilutions ranging from 2 to 512 mg liter-1 Scanning electron microscopy was used to visualize the aggregation patterns, while confocal laser scanning microscopy and microrespirometry were used to visualize biofilm growth patterns. Disruption of MABSC aggregates increased susceptibility to amikacin, tigecycline, kanamycin, azithromycin, imipenem, cefoxitin, and clarithromycin (P < 0.05, n = 29 to 31). Oxygenation enhanced the killing of disaggregated MABSC isolates by amikacin (P < 0.05) by 1 to 6 log units when 2 to 512 mg liter-1 of amikacin was used. This study explains why current drug susceptibility testing results correlate poorly with treatment outcomes. The conditions achieved by oxic culturing of planktonic isolates in vitro do not resemble the hypoxic conditions in CF patient lungs. Biofilm disruption and increased O2 availability during antibiotic therapy may be new therapeutic strategies for chronic MABSC infection.
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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11
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Jakkala K, Ajitkumar P. Hypoxic Non-replicating Persistent Mycobacterium tuberculosis Develops Thickened Outer Layer That Helps in Restricting Rifampicin Entry. Front Microbiol 2019; 10:2339. [PMID: 31681204 PMCID: PMC6797554 DOI: 10.3389/fmicb.2019.02339] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 09/25/2019] [Indexed: 01/25/2023] Open
Abstract
Bacteria undergo adaptive morphological changes to survive under stress conditions. The present work documents the morphological changes in Mycobacterium tuberculosis (Mtb) cells cultured under hypoxic condition using Wayne’s in vitro hypoxia model involving non-replicating persistence stages 1 and 2 (NRP stage 1 and NRP stage 2) and reveals their physiological significance. Transmission electron microscopy of the NRP stage 2 cells showed uneven but thick outer layer (TOL), unlike the evenly thin outer layer of the actively growing mid-log phase (MLP) cells. On the contrary, the saprophytic Mycobacterium smegmatis NRP stage 2 cells lacked TOL. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) of the Mtb NRP stage 2 cells confirmed the rough uneven surface unlike the smooth surface of the MLP cells. Zeta potential measurements showed high negative charge on the surface of NRP stage 2 cells and polysaccharide specific calcofluor white (CFW) staining of the cells revealed high content of polysaccharide in the TOL. This observation was supported by the real-time PCR data showing high levels of expression of the genes involved in the synthesis of sugars, such as trehalose, mannose and others, which are implicated in polysaccharide synthesis. Experiments to understand the physiological significance of the TOL revealed restricted entry of the biologically low-active 5-carboxyfluorescein-rifampicin (5-FAM-RIF), at concentrations equivalent to microbicidal concentrations of the unconjugated biologically active rifampicin, into the NRP stage 2 cells, unlike in the MLP cells. Further, as expected, mechanical removal of the TOL by mild bead beating or release of the NRP stage 2 cells from hypoxia into normoxia in fresh growth medium also significantly increased 5-FAM-RIF permeability into the NRP stage 2 cells to an extent comparable to that into the MLP cells. Taken together, these observations revealed that Mtb cells under hypoxia develop TOL that helps in restricting rifampicin entry, thereby conferring rifampicin tolerance.
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Affiliation(s)
- Kishor Jakkala
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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12
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Grooms DL, Bolin SR, Plastow JL, Lim A, Hattey J, Durst PT, Rust SR, Allen MS, Buskirk DD, Smith RW. Survival of Mycobacterium bovis during forage ensiling. Am J Vet Res 2019; 80:87-94. [PMID: 30605026 DOI: 10.2460/ajvr.80.1.87] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether Mycobacterium bovis remains viable in ensiled forages. SAMPLE Alfalfa, mixed mostly grass, and corn silages. PROCEDURES For each of 10 sampling days, six 250-g replicate samples of each feedstuff were created and placed in a film pouch that could be vacuum sealed to simulate the ensiling process. Within each set of replicate samples, 4 were inoculated with 10 mL of mycobacterial liquid culture medium containing viable M bovis and 2 were inoculated with 10 mL of sterile mycobacterial liquid culture medium (controls) on day 0. Pouches were vacuum sealed and stored in the dark at room temperature. On the designated sampling day, 1 control pouch was submitted for forage analysis, and the other pouches were opened, and forage samples were obtained for M bovis culture and analysis with a PCR assay immediately and 24 hours later. RESULTS None of the control samples had positive M bovis culture or PCR assay results. Among M bovis-inoculated samples, the organism was not cultured from alfalfa and corn silage for > 2 days but was cultured from mixed mostly grass silage for 28 days after inoculation and ensiling initiation. Mycobacterium bovis DNA was detected by PCR assay in samples of all 3 feedstuffs throughout the 112-day observation period. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that properly ensiled forages would be an unlikely source for M bovis transmission to cattle. Further research is necessary to determine whether ensiling kills M bovis or forces it to become dormant and, if the latter, elucidate the conditions that cause it to revert to an infectious state.
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De Maio F, Battah B, Palmieri V, Petrone L, Corrente F, Salustri A, Palucci I, Bellesi S, Papi M, Rubino S, Sali M, Goletti D, Sanguinetti M, Manganelli R, De Spirito M, Delogu G. PE_PGRS3 of Mycobacterium tuberculosis is specifically expressed at low phosphate concentration, and its arginine-rich C-terminal domain mediates adhesion and persistence in host tissues when expressed in Mycobacterium smegmatis. Cell Microbiol 2018; 20:e12952. [PMID: 30192424 DOI: 10.1111/cmi.12952] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/22/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
PE_PGRSs of Mycobacterium tuberculosis (Mtb) represent a family of complex and peculiar proteins whose role and function remain elusive. In this study, we investigated PE_PGRS3 and PE_PGRS4, two highly homologous PE_PGRSs encoded by two contiguous genes in the Mtb genome. Using a gene-reporter system in Mycobacterium smegmatis (Ms) and transcriptional analysis in Mtb, we show that PE_PGRS3, but not PE_PGRS4, is specifically expressed under low phosphate concentrations. Interestingly, PE_PGRS3, but not PE_PGRS4, has a unique, arginine-rich C-terminal domain of unknown function. Heterologous expression of PE_PGRS3 in Ms was used to demonstrate cellular localisation of the protein on the mycobacterial surface, where it significantly affects net surface charge. Moreover, expression of full-length PE_PGRS3 enhanced adhesion of Ms to murine macrophages and human epithelial cells and improved bacterial persistence in spleen tissue following infection in mice. Expression of the PE_PGRS3 functional deletion mutant lacking the C-terminal domain in Ms did not enhance adhesion to host cells, showing a phenotype similar to the Ms parental strain. Interestingly, enhanced persistence of Ms expressing PE_PGRS3 did not correlate with increased concentrations of inflammatory cytokines. These results point to a critical role for the ≈ 80 amino acids long, arginine-rich C-terminal domain of PE_PGRS3 in tuberculosis pathogenesis.
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Affiliation(s)
- Flavio De Maio
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Basem Battah
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy.,Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Valentina Palmieri
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Linda Petrone
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Francesco Corrente
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessandro Salustri
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ivana Palucci
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Silvia Bellesi
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Massimiliano Papi
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Rubino
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Michela Sali
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Delia Goletti
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Marco De Spirito
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giovanni Delogu
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
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Grandjean-Lapierre S, Thiberville SD, Fellag M, Eghazarian C, Bouzid F, Gavril C, Drancourt M. Recurrent bilateral Mycobacterium bovis necrotizing epididymitis: a case report. BMC Res Notes 2018; 11:308. [PMID: 29776430 PMCID: PMC5960082 DOI: 10.1186/s13104-018-3426-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/10/2018] [Indexed: 12/01/2022] Open
Abstract
Background Mycobacterium bovis causing tuberculosis in animals is responsible for zoonotic tuberculosis in patients. Veterinary control measures and milk pasteurization has led to a significant decrease in human cases of M. bovis infections in developed countries. Case presentation We diagnosed recurrent M. bovis epididymitis in a 63-year old Caucasian man without any signs of pulmonary or disseminated disease. Relevant epidemiological expositions included camel milk drinking during prolonged travels in Niger, prior to initial clinical manifestations. The diagnosis was firmly established by mass spectrometry and DNA sequencing on epididymis surgical biopsy specimens. We detail therapeutic management which included surgical epididymectomy and hydrocele repair. Conclusion As for other M. tuberculosis complex species, the genitourinary tract represents a frequent site of secondary dissemination and latency for M. bovis. Isolated epididymis infection is a newly documented manifestation of M. bovis disease.
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Affiliation(s)
- Simon Grandjean-Lapierre
- Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005, Marseille, France
| | | | - Mustapha Fellag
- Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005, Marseille, France
| | | | - Feriel Bouzid
- Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005, Marseille, France
| | - Christina Gavril
- Centre Hospitalier du Pays d'Aix, 13616, Aix en Provence, France
| | - Michel Drancourt
- Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005, Marseille, France.
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15
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Parrish N, Vadlamudi A, Goldberg N. Anaerobic adaptation of Mycobacterium avium subspecies paratuberculosis in vitro: similarities to M. tuberculosis and differential susceptibility to antibiotics. Gut Pathog 2017; 9:34. [PMID: 28616081 PMCID: PMC5466712 DOI: 10.1186/s13099-017-0183-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/01/2017] [Indexed: 01/29/2023] Open
Abstract
Background Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of Johne’s disease in ruminants and is associated with Crohn’s disease (CD) in humans, although the latter remains controversial. In this study, we investigated the ability of MAP to adapt to anaerobic growth using the “Wayne” model of non-replicating persistence (NRP) developed for M. tuberculosis. Results All strains adapted to anaerobiosis over time in a manner similar to that seen with MTB. Susceptibility to 12 antibiotics varied widely between strains under aerobic conditions. Under anaerobic conditions, no drugs caused significant growth inhibition (>0.5 log) except metronidazole, resulting in an average decrease of ~2 logs. Conclusions These results demonstrate that MAP is capable of adaptation to NRP similar to that observed for MTB with differential susceptibility to antibiotics under aerobic versus anaerobic conditions. Such findings have significant implications for our understanding of the pathogenesis of MAP in vivo and the treatment of CD should this organism be established as the causative agent.
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Affiliation(s)
- Nicole Parrish
- The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Meyer B1-193, Baltimore, Maryland USA
| | - Aravinda Vadlamudi
- The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Meyer B1-193, Baltimore, Maryland USA
| | - Neil Goldberg
- Saint Joseph Medical Center, University of Maryland, Towson, Maryland USA
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16
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Delamanid Kills Dormant Mycobacteria In Vitro and in a Guinea Pig Model of Tuberculosis. Antimicrob Agents Chemother 2017; 61:AAC.02402-16. [PMID: 28373190 DOI: 10.1128/aac.02402-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 03/24/2017] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis (TB) treatment is long and requires multiple drugs, likely due to various phenotypes of TB bacilli with variable drug susceptibilities. Drugs with broad activity are urgently needed. This study aimed to evaluate delamanid's activity against growing or dormant bacilli in vitro as well as in vivo Cultures of Mycobacterium bovis BCG Tokyo under aerobic and anaerobic conditions were used to study the activity of delamanid against growing and dormant bacilli, respectively. Delamanid exhibited significant bactericidal activity against replicating and dormant bacilli at or above concentrations of 0.016 and 0.4 mg/liter, respectively. To evaluate delamanid's antituberculosis activity in vivo, we used a guinea pig model of chronic TB infection in which the lung lesions were similar to those in human TB disease. In the guinea pig TB model, a daily dose of 100 mg delamanid/kg of body weight for 4 or 8 weeks demonstrated strong bactericidal activity against Mycobacterium tuberculosis Importantly, histological examination revealed that delamanid killed TB bacilli within hypoxic lesions of the lung. The combination regimens containing delamanid with rifampin and pyrazinamide or delamanid with levofloxacin, ethionamide, pyrazinamide, and amikacin were more effective than the standard regimen (rifampin, isoniazid, and pyrazinamide). Our data show that delamanid is effective in killing both growing and dormant bacilli in vitro and in the guinea pig TB model. Adding delamanid to current TB regimens may improve treatment outcomes, as demonstrated in recent clinical trials with pulmonary multidrug-resistant (MDR) TB patients. Delamanid may be an important drug for consideration in the construction of new regimens to shorten TB treatment duration.
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17
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Alaridah N, Lutay N, Tenland E, Rönnholm A, Hallgren O, Puthia M, Westergren-Thorsson G, Godaly G. Mycobacteria Manipulate G-Protein-Coupled Receptors to Increase Mucosal Rac1 Expression in the Lungs. J Innate Immun 2016; 9:318-329. [PMID: 28013312 DOI: 10.1159/000453454] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Mycobacterium bovis bacille Calmette-Guérin (BCG) is currently the only approved vaccine against tuberculosis (TB). BCG mimics M. tuberculosis (Mtb) in its persistence in the body and is used as a benchmark to compare new vaccine candidates. BCG was originally designed for mucosal vaccination, but comprehensive knowledge about its interaction with epithelium is currently lacking. We used primary airway epithelial cells (AECs) and a murine model to investigate the initial events of mucosal BCG interactions. Furthermore, we analysed the impact of the G-protein-coupled receptors (GPCRs), CXCR1 and CXCR2, in this process, as these receptors were previously shown to be important during TB infection. BCG infection of AECs induced GPCR-dependent Rac1 up-regulation, resulting in actin redistribution. The altered distribution of the actin cytoskeleton involved the MAPK signalling pathway. Blocking of the CXCR1 or CXCR2 prior to infection decreased Rac1 expression, and increased epithelial transcriptional activity and epithelial cytokine production. BCG infection did not result in epithelial cell death as measured by p53 phosphorylation and annexin. This study demonstrated that BCG infection of AECs manipulated the GPCRs to suppress epithelial signalling pathways. Future vaccine strategies could thus be improved by targeting GPCRs.
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Affiliation(s)
- Nader Alaridah
- Division of Laboratory Medicine, Department of MIG, Lund University, Lund, Sweden
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18
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Rizvi N, Singh A, Yadav M, Hussain SR, Siddiqui S, Kumar V, Ali S, Agarwal A. Role of alpha-crystallin, early-secreted antigenic target 6-kDa protein and culture filtrate protein 10 as novel diagnostic markers in osteoarticular tuberculosis. J Orthop Translat 2016; 6:18-26. [PMID: 30035079 PMCID: PMC5987026 DOI: 10.1016/j.jot.2016.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 11/23/2015] [Accepted: 01/05/2016] [Indexed: 02/05/2023] Open
Abstract
Osteoarticular tuberculosis constitutes about 3% of all tuberculosis cases. Early and accurate diagnosis of tuberculosis is a challenging problem especially in the case of osteoarticular tuberculosis owing to the lower number of bacilli. However, an accurate and timely diagnosis of the disease results in an improved efficacy of the given treatment. Besides the limitations of conventional methods, nowadays molecular diagnostic techniques have emerged as a major breakthrough for the early diagnosis of tuberculosis with high sensitivity and specificity. Alpha-crystallin is a dominantly expressed protein responsible for the long viability of the pathogen during the latent phase under certain stress conditions such as hypoxia and nitric oxide stress. Two other proteins-early secreted antigenic target-6 and culture filtrate protein-10-show high expression in the active infective phase of Mycobacterium tuberculosis. In this article, we focus on the different proteins expressed dominantly in latent/active tuberculosis, and which may be further used as prognostic biomarkers for diagnosing tuberculosis, both in latent and active phases.
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Affiliation(s)
- Nazia Rizvi
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Ajai Singh
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Manish Yadav
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Syed Rizwan Hussain
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Salma Siddiqui
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Vineet Kumar
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Sabir Ali
- Department of Orthopaedic Surgery, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
| | - Avinash Agarwal
- Department of Medicine, King George's Medical University, Lucknow 226 018, Uttar Pradesh, India
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19
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Lipworth S, Hammond RJH, Baron VO, Hu Y, Coates A, Gillespie SH. Defining dormancy in mycobacterial disease. Tuberculosis (Edinb) 2016; 99:131-142. [PMID: 27450015 DOI: 10.1016/j.tube.2016.05.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/06/2016] [Accepted: 05/23/2016] [Indexed: 11/19/2022]
Abstract
Tuberculosis remains a threat to global health and recent attempts to shorten therapy have not succeeded mainly due to cases of clinical relapse. This has focussed attention on the importance of "dormancy" in tuberculosis. There are a number of different definitions of the term and a similar multiplicity of different in vitro and in vivo models. The danger with this is the implicit assumption of equivalence between the terms and models, which will make even more difficult to unravel this complex conundrum. In this review we summarise the main models and definitions and their impact on susceptibility of Mycobacterium tuberculosis. We also suggest a potential nomenclature for debate. Dormancy researchers agree that factors underpinning this phenomenon are complex and nuanced. If we are to make progress we must agree the terms to be used and be consistent in using them.
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Affiliation(s)
- S Lipworth
- School of Medicine, University of St Andrews, Biomedical Science Building, North Haugh, St Andrews KY16 9TF, United Kingdom
| | - R J H Hammond
- School of Medicine, University of St Andrews, Biomedical Science Building, North Haugh, St Andrews KY16 9TF, United Kingdom
| | - V O Baron
- School of Medicine, University of St Andrews, Biomedical Science Building, North Haugh, St Andrews KY16 9TF, United Kingdom
| | - Yanmin Hu
- Institute for Infection and Immunity, St George's, University of London, London SW17 ORE, United Kingdom
| | - A Coates
- Institute for Infection and Immunity, St George's, University of London, London SW17 ORE, United Kingdom
| | - S H Gillespie
- School of Medicine, University of St Andrews, Biomedical Science Building, North Haugh, St Andrews KY16 9TF, United Kingdom.
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20
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Anti-dormant mycobacterial activity and target molecule of melophlins, tetramic acid derivatives isolated from a marine sponge of Melophlus sp. J Nat Med 2016; 70:467-75. [DOI: 10.1007/s11418-016-1005-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/25/2016] [Indexed: 10/21/2022]
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21
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Mukherjee D, Zou H, Liu S, Beuerman R, Dick T. Membrane-targeting AM-0016 kills mycobacterial persisters and shows low propensity for resistance development. Future Microbiol 2016; 11:643-50. [DOI: 10.2217/fmb-2015-0015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Aim: To test the hypothesis that targeting the cytoplasmic membrane may be an effective way to kill persister mycobacteria and delay the emergence of resistance. Methods: In vitro activity of AM-0016, a novel xanthone-based antibacterial, was assessed against growing and persister tubercle bacilli. Resistance mutation frequencies were determined. Biochemical membrane and electron microscopic analyses were carried out. Results: AM-0016 rapidly sterilized growing tubercle bacillus cultures and displayed strong bactericidal activity against persister bacteria. Spontaneous resistance mutation frequency was lower than 10-8. Exposure to AM-0016 resulted in rapid collapse of the membrane potential. Imaging revealed deformation of the cell envelope. Conclusion: Targeting the cytoplasmic membrane may be an attractive approach to eliminate persister mycobacteria and slow down the emergence of genetic drug resistance.
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Affiliation(s)
- Devika Mukherjee
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545
| | - Hanxun Zou
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856
| | - Shouping Liu
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856
- SRP Neuroscience & Behavioural Disorders, Duke-NUS Graduate Medical School, Singapore 169857
| | - Roger Beuerman
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower Level 6, Singapore 169856
- SRP Neuroscience & Behavioural Disorders, Duke-NUS Graduate Medical School, Singapore 169857
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074
| | - Thomas Dick
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545
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22
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Kirtania P, Ghosh S, Bhawsinghka N, Chakladar M, Das Gupta SK. Vitamin C induced DevR-dependent synchronization of Mycobacterium smegmatis growth and its effect on the proliferation of mycobacteriophage D29. FEMS Microbiol Lett 2016; 363:fnw097. [PMID: 27190284 DOI: 10.1093/femsle/fnw097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 01/18/2023] Open
Abstract
Vitamin C is known to inhibit mycobacterial growth by acting as a hypoxia inducing agent. While investigating how mycobacteriophage growth is influenced by hypoxic conditions induced by vitamin C, using Mycobacterium smegmatis- mycobacteriophage D29 as a model system, it was observed that prior exposure of the host to such conditions resulted in increased burst size of the phage. Vitamin C pre-exposure was also found to induce synchronous growth of the host. A mutant defective in DevR, the response regulator that controls hypoxic responses in mycobacteria, neither supported higher phage bursts nor was it able to undergo synchronized growth following vitamin C pre-exposure, indicating thereby that the two phenomena are interrelated. Further evidence supporting such an interrelationship was obtained from the observation that phage burst sizes varied depending on the stage of synchronous growth that the host cells were in, at the time of infection-higher bursts were observed in the resting/synthetic phases and lower in the dividing ones. The effects were specific in nature as synchronization by an unrelated method, known as 'crowding', did not lead to the same consequence. The results indicate that growth synchronization induced by vitamin C treatment is a DevR-dependent phenomenon which is exploited by mycobacteriophage D29 to grow in larger numbers.
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Affiliation(s)
- Prithwiraj Kirtania
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Shreya Ghosh
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Niketa Bhawsinghka
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Madhumita Chakladar
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Sujoy K Das Gupta
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
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Moreira W, Aziz DB, Dick T. Boromycin Kills Mycobacterial Persisters without Detectable Resistance. Front Microbiol 2016; 7:199. [PMID: 26941723 PMCID: PMC4761863 DOI: 10.3389/fmicb.2016.00199] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/05/2016] [Indexed: 11/13/2022] Open
Abstract
Boromycin is a boron-containing polyether macrolide antibiotic isolated from Streptomyces antibioticus. It was shown to be active against Gram positive bacteria and to act as an ionophore for potassium ions. The antibiotic is ineffective against Gram negative bacteria where the outer membrane appears to block access of the molecule to the cytoplasmic membrane. Here we asked whether boromycin is active against Mycobacterium tuberculosis which, similar to Gram negative bacteria, possesses an outer membrane. The results show that boromycin is a potent inhibitor of mycobacterial growth (MIC50 = 80 nM) with strong bactericidal activity against growing and non-growing drug tolerant persister bacilli. Exposure to boromycin resulted in a rapid loss of membrane potential, reduction of the intracellular ATP level and leakage of cytoplasmic protein. Consistent with boromycin acting as a potassium ionophore, addition of KCl to the medium blocked its antimycobacterial activity. In contrast to the potent antimycobacterial activities of the polyether macrolide, its cytotoxicity and haemolytic activity were low (CC50 = 30 μM, HC50 = 40 μM) with a selectivity index of more than 300. Spontaneous resistant mutants could not be isolated suggesting a mutation frequency of less than 10(-9)/CFU. Taken together, the results suggests that targeting mycobacterial transmembrane ion gradients may be an attractive chemotherapeutic intervention level to kill otherwise drug tolerant persister bacilli, and to slow down the development of genetic antibiotic resistance.
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Affiliation(s)
- Wilfried Moreira
- Antibacterial Drug Discovery Laboratory, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Dinah B Aziz
- Antibacterial Drug Discovery Laboratory, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Thomas Dick
- Antibacterial Drug Discovery Laboratory, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
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Sood S, Yadav A, Shrivastava R. Mycobacterium aurum is Unable to Survive Mycobacterium tuberculosis Latency Associated Stress Conditions: Implications as Non-suitable Model Organism. Indian J Microbiol 2016; 56:198-204. [PMID: 27570312 DOI: 10.1007/s12088-016-0564-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/02/2016] [Indexed: 12/28/2022] Open
Abstract
Mycobacterium tuberculosis manages to remain latent in the human body regardless of extensive chemotherapy. Complete eradication of tuberculosis (TB) requires treatment strategies targeted against latent form of infection, in addition to the current regimen of antimycobacterials. Many in vitro and in vivo models have been proposed to imitate latent TB infection, yet none of them is able to completely mimic latent infection state of M. tuberculosis. Highly infectious nature of the pathogen requiring BSL3 facilities and its long generation time further add to complications. M. aurum has been proposed as an important model organism for high throughput screening of drugs and exhibits high genomic similarity with that of M. tuberculosis. Thus, the present study was undertaken to explore if M. aurum could be used as a surrogate organism for studies related to M. tuberculosis latent infection. M. aurum was subjected to in vitro conditions of oxygen depletion, lack of nutrients and acidic stress encountered by latent M. tuberculosis bacteria. CFU count of M. aurum cells along with any change in cell shape and size was recorded at regular intervals during the stress conditions. M. aurum cells were unable to survive for extended periods under all three conditions used in the study. Thus, our studies suggest that M. aurum is not a suitable organism to mimic M. tuberculosis persistent infection under in vitro conditions, and further studies are required on different species for the establishment of a fast growing species as a suitable model for M. tuberculosis persistent infection.
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Affiliation(s)
- Shivani Sood
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 India
| | - Anant Yadav
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 India
| | - Rahul Shrivastava
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 India
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Velayati AA, Abeel T, Shea T, Konstantinovich Zhavnerko G, Birren B, Cassell GH, Earl AM, Hoffner S, Farnia P. Populations of latent Mycobacterium tuberculosis lack a cell wall: Isolation, visualization, and whole-genome characterization. Int J Mycobacteriol 2015; 5:66-73. [PMID: 26927992 DOI: 10.1016/j.ijmyco.2015.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 11/28/2015] [Accepted: 12/09/2015] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE/BACKGROUND Mycobacterium tuberculosis (MTB) causes active tuberculosis (TB) in only a small percentage of infected people. In most cases, the infection is clinically latent, where bacilli can persist in human hosts for years without causing disease. Surprisingly, the biology of such persister cells is largely unknown. This study describes the isolation, identification, and whole-genome sequencing (WGS) of latent TB bacilli after 782days (26months) of latency (the ability of MTB bacilli to lie persistent). METHODS The in vitro double-stress model of latency (oxygen and nutrition) was designed for MTB culture. After 26months of latency, MTB cells that persisted were isolated and investigated under light and atomic force microscopy. Spoligotyping and WGS were performed to verify the identity of the strain. RESULTS We established a culture medium in which MTB bacilli arrest their growth, reduce their size (0.3-0.1μm), lose their acid fastness (85-90%) and change their shape. Spoligopatterns of latent cells were identical to original H37Rv, with differences observed at spacers two and 14. WGS revealed only a few genetic changes relative to the already published H37Rv reference genome. Among these was a large 2064-bp insertion (RvD6), which was originally detected in both H37Ra and CDC1551, but not H37Rv. CONCLUSION Here, we show cell-wall free cells of MTB bacilli in their latent state, and the biological adaptation of these cells was more phenotypic in nature than genomic. These cell-wall free cells represent a good model for understanding the nature of TB latency.
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Affiliation(s)
- Ali Akbar Velayati
- Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Thomas Abeel
- Genome Sequencing & Analysis Program, The Broad Institute of MIT & Harvard, Cambridge, MA, USA; Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
| | - Terrance Shea
- Genome Sequencing & Analysis Program, The Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | | | - Bruce Birren
- Genome Sequencing & Analysis Program, The Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | - Gail H Cassell
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA
| | - Ashlee M Earl
- Genome Sequencing & Analysis Program, The Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | - Sven Hoffner
- Department of Microbiology, The Public Health Agency of Sweden, Solna, Sweden
| | - Parissa Farnia
- Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Sohaskey CD, Voskuil MI. In vitro models that utilize hypoxia to induce non-replicating persistence in Mycobacteria. Methods Mol Biol 2015; 1285:201-13. [PMID: 25779317 DOI: 10.1007/978-1-4939-2450-9_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The Wayne model and Rapid Anaerobic Dormancy model are widely used methods to analyze the response of Mycobacterium tuberculosis to hypoxia and anaerobiosis. In these models tubercle bacilli are grown in sealed tubes in which bacilli aerobic respiration produces a temporal oxygen gradient. The gradual depletion of oxygen results in a non-replicating persistent culture capable of extended microaerobic and anaerobic survival. Here we describe both models used to induce hypoxic non-replicating persistence in M. tuberculosis. Additional techniques such as the isolation of RNA, the detection of nitrate reductase activity and ATP levels, and the determination of the NAD(+)/NADH ratio are described.
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Affiliation(s)
- Charles D Sohaskey
- Department of Veterans Affairs Medical Center, Long Beach, CA, 90822, USA,
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Purushotham G, Sarva KB, Blaszczyk E, Rajagopalan M, Madiraju MV. Mycobacterium tuberculosis oriC sequestration by MtrA response regulator. Mol Microbiol 2015. [PMID: 26207528 DOI: 10.1111/mmi.13144] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The regulators of Mycobacterium tuberculosis DNA replication are largely unknown. Here, we demonstrate that in synchronously replicating M. tuberculosis, MtrA access to origin of replication (oriC) is enriched in the post-replication (D) period. The increased oriC binding results from elevated MtrA phosphorylation (MtrA∼P) as evidenced by reduced expression of dnaN, dnaA and increased expression of select cell division targets. Overproduction of gain-of-function MtrAY102C advanced the MtrA oriC access to the C period, reduced dnaA and dnaN expression, interfered with replication synchrony and compromised cell division. Overproduction of wild-type (MtrA+) or phosphorylation-defective MtrAD56N did not promote oriC access in the C period, nor affected cell cycle progression. MtrA interacts with DnaA signaling a possibility that DnaA helps load MtrA on oriC. Therefore, oriC sequestration by MtrA∼P in the D period may normally serve to prevent untimely initiations and that DnaA-MtrA interactions may facilitate regulated oriC replication. Finally, despite the near sequence identity of MtrA in M. smegmatis and M. tuberculosis, the M. smegmatis oriC is not MtrA-target. We conclude that M. tuberculosis oriC has evolved to be regulated by MtrA and that cell cycle progression in this organisms are governed, at least in part, by oscillations in the MtrA∼P levels.
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Affiliation(s)
- Gorla Purushotham
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Krishna B Sarva
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Ewelina Blaszczyk
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Malini Rajagopalan
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Murty V Madiraju
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
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28
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Arai M, Kamiya K, Pruksakorn P, Sumii Y, Kotoku N, Joubert JP, Moodley P, Han C, Shin D, Kobayashi M. Anti-dormant mycobacterial activity and target analysis of nybomycin produced by a marine-derived Streptomyces sp. Bioorg Med Chem 2015; 23:3534-41. [DOI: 10.1016/j.bmc.2015.04.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 11/16/2022]
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Goldberg ND, Vadlamudi A, Parrish N. Treatment of refractory Crohn's disease and pyoderma gangrenosum with a combination regimen of rifaximin, gentamicin and metronidazole. Case Rep Gastroenterol 2015; 9:25-8. [PMID: 25802494 PMCID: PMC4342856 DOI: 10.1159/000369965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The etiology of Crohn's disease (CD) remains controversial. It is hypothesized that CD is the result of an abnormal immune response to the gut flora in genetically susceptible hosts. However, an infectious etiology has not been completely ruled out. Antibiotics have been utilized with some success to modify the course of the disease. Here, we report a patient with CD and pyoderma gangrenosum refractory to standard therapy, including biologics, who achieved remission with a combination of rifaximin, gentamicin and metronidazole.
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Affiliation(s)
- Neil D Goldberg
- St. Joseph Medical Center, The University of Maryland, Towson, Md., USA
| | | | - Nicole Parrish
- The Johns Hopkins Medical Institutions, Baltimore, Md., USA
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Flores-Moreno K, Celis-Meneses JS, Meneses-Ruiz DM, Castillo-Rodal AI, Orduña P, Montiel BA, López-Vidal Y. Potential cross-reactivity of monoclonal antibodies against clinically relevant mycobacteria. Clin Exp Immunol 2014; 177:454-63. [PMID: 24580144 DOI: 10.1111/cei.12309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2014] [Indexed: 12/31/2022] Open
Abstract
Tuberculosis is a disease caused by the Mycobacterium tuberculosis complex (MTb). In 2011, global mortality due to tuberculosis was 1·4 million individuals. The only available vaccine is the attenuated M. bovis [bacillus Calmette-Guérin (BCG)] strain, which confers variable protection against pulmonary tuberculosis. Some widely distributed non-tuberculous mycobacteria (NTM), such as M. avium and M. arupense, are also potential pathogens for humans. This work aimed to produce and characterize monoclonal antibodies against the M. bovis BCG Mexico strain of the MTb, M. avium subs. hominissuis and the M. arupense strain from NTM. Hybridomas were produced from splenocytes of BALB/c female mice immunized with radiation-inactivated mycobacteria, and the immunoglobulin (Ig)G2a antibody-producing clones with the highest antigenic recognition were selected. The selected clones, Mbv 2A10 for M. bovis BCG Mexico, Mav 3H1 for M. avium and Mar 2D10 for M. arupense, were used in further studies. Enzyme-linked immunosorbent assay (ELISA) and immune proteomics analyses characterized the clones as having the highest cross-reactivity with mycobacteria. Using mass spectrometry, a number of proteins recognized by the monoclonal antibody (mAb) clones were identified. These proteins had roles in metabolic processes, hypoxia, cell cycle and dormancy. In addition, a Clustal W and Immune Epitope Database (IEDB) in-silico analysis was performed in protein sequences that result in the conserved regions within probability epitopes that could be recognized for Mbv2A10 and Mav3H1 clones.
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Affiliation(s)
- K Flores-Moreno
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
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31
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Arai M, Han C, Yamano Y, Setiawan A, Kobayashi M. Aaptamines, marine spongean alkaloids, as anti-dormant mycobacterial substances. J Nat Med 2014; 68:372-6. [PMID: 24414399 DOI: 10.1007/s11418-013-0811-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 12/16/2013] [Indexed: 10/25/2022]
Abstract
A new aaptamine class alkaloid, designated 2-methoxy-3-oxoaaptamine (1), together with seven known aaptamines (2-8) were isolated from a marine sponge of Aaptos sp. as anti-mycobacterial substances against active and dormant bacilli. The chemical structure of 1 was determined on the basis of spectroscopic analysis. Compound 1 was anti-mycobacterial against Mycobacterium smegmatis in both active growing and dormancy-inducing hypoxic conditions with a minimum inhibitory concentration (MIC) of 6.25 μg/ml, and compounds 2, 5, 6, and 7 showed anti-mycobacterial activities under hypoxic condition selectively, with MIC values of 1.5-6.25 μg/ml.
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Affiliation(s)
- Masayoshi Arai
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamada-oka 1-6, Suita, Osaka, 565-0871, Japan,
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Arai M, Yamano Y, Setiawan A, Kobayashi M. Identification of the Target Protein of Agelasine D, a Marine Sponge Diterpene Alkaloid, as an Anti-dormant Mycobacterial Substance. Chembiochem 2013; 15:117-23. [DOI: 10.1002/cbic.201300470] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Indexed: 11/07/2022]
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Jiménez B, Hinojoza-Loza E, Flores-Valdez M, Prado-Montes de Oca E, Allen K, Estrada-Chávez C, Herrera-Rodríguez S, Flores-Fernández J, Martínez-Velázquez M, Hernández-Gutiérrez R, Alvarez A. Expression of non-replicating persistence associated genes of Mycobacterium bovis in lymph nodes from skin test-reactor cattle. Microb Pathog 2013; 61-62:23-8. [DOI: 10.1016/j.micpath.2013.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/11/2013] [Accepted: 04/23/2013] [Indexed: 11/28/2022]
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Sivaramakrishnan S, de Montellano PRO. The DosS-DosT/DosR Mycobacterial Sensor System. BIOSENSORS 2013; 3:259-282. [PMID: 25002970 PMCID: PMC4082495 DOI: 10.3390/bios3030259] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/15/2013] [Accepted: 06/26/2013] [Indexed: 11/16/2022]
Abstract
DosS/DosR is a two-component regulatory system in which DosS, a heme-containing sensor also known as DevS, under certain conditions undergoes autophosphorylation and then transfers the phosphate to DosR, a DNA-binding protein that controls the entry of Mycobacterium tuberculosis and other mycobacteria into a latent, dormant state. DosT, a second sensor closely related to DosS, is present in M. tuberculosis and participates in the control of the dormancy response mediated by DosR. The binding of phosphorylated DosR to DNA initiates the expression of approximately fifty dormancy-linked genes. DosT is accepted to be a gas sensor that is activated in the ferrous state by the absence of an oxygen ligand or by the binding of NO or CO. DosS functions in a similar fashion as a gas sensor, but contradictory evidence has led to the suggestion that it also functions as a redox state sensor. This review focuses on the structure, biophysical properties, and function of the DosS/DosT heme sensors.
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Affiliation(s)
- Santhosh Sivaramakrishnan
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA 94158, USA;
| | - Paul R Ortiz de Montellano
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA 94158, USA;
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35
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Håkansson G, Lutay N, Andersson M, Hallgren O, Westergren-Thorsson G, Svensson M, Godaly G. Epithelial G protein-coupled receptor kinases regulate the initial inflammatory response during mycobacterial infection. Immunobiology 2012; 218:984-94. [PMID: 23312955 DOI: 10.1016/j.imbio.2012.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 11/12/2012] [Accepted: 11/14/2012] [Indexed: 01/04/2023]
Abstract
The interaction between mycobacteria and epithelium is unexplored, but may determine the outcome of the infection. We have analyzed the role of two G protein-coupled receptors, CXCR1 and CXCR2 that are important regulators of many pulmonary diseases. We found that mycobacteria significantly increased the expression of both CXCR1 and CXCR2 on alveolar epithelial cells and both receptors were found to be important for neutrophil diapedesis across primary endothelial cells towards infected mucosa. Mycobacteria, lipoarabinomannan or 19-kDa glycolipoprotein up-regulated the inhibitory G protein-coupled receptor kinase (GRK)2, while GRK3 was less affected. Mycobacteria-induced GRK2 up-regulation decreased chemokine transcription and secretion thereby affecting the neutrophil recruitment to infected mucosa. These events were completely abolished by blocking these receptors prior to infection as the blocking increased epithelial immune responses. We have identified novel interactions occurring in the initial phase of mycobacterial infections by which mycobacterial manipulate epithelial inflammatory responses.
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Affiliation(s)
- Gisela Håkansson
- Department of MIG, Division of Laboratory Medicine, Lund University, Lund, Sweden
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36
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Walter WD, Anderson CW, Smith R, Vanderklok M, Averill JJ, VerCauteren KC. On-farm mitigation of transmission of tuberculosis from white-tailed deer to cattle: literature review and recommendations. Vet Med Int 2012; 2012:616318. [PMID: 22991687 PMCID: PMC3444046 DOI: 10.1155/2012/616318] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 11/17/2022] Open
Abstract
The Animal Industry Division of the Michigan Department of Agriculture and Rural Development (MDARD) has been challenged with assisting farmers with modifying farm practices to reduce potential for exposure to Mycobacterium bovis from wildlife to cattle. The MDARD recommendations for on-farm risk mitigation practices were developed from experiences in the US, UK and Ireland and a review of the scientific literature. The objectives of our study were to review the present state of knowledge on M. bovis excretion, transmission, and survival in the environment and the interactions of wildlife and cattle with the intention of determining if the current recommendations by MDARD on farm practices are adequate and to identify additional changes to farm practices that may help to mitigate the risk of transmission. This review will provide agencies with a comprehensive summary of the scientific literature on mitigation of disease transmission between wildlife and cattle and to identify lacunae in published research.
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Affiliation(s)
- W. David Walter
- National Wildlife Research Center, Animal and Plant Health Inspection Services, United States Department of Agriculture, 4101 LaPorte Ave, Fort Collins, CO 80521, USA
- US Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit, Pennsylvania State University, 403 Forest Resources Building, University Park, PA 16802, USA
| | - Charles W. Anderson
- National Wildlife Research Center, Animal and Plant Health Inspection Services, United States Department of Agriculture, 4101 LaPorte Ave, Fort Collins, CO 80521, USA
- Missouri Department of Conservation, Resource Science Division, 551 Joe Jones Boulevard, West Plains, MO 65775, USA
| | - Rick Smith
- Animal Industry Division, Michigan Department of Agriculture and Rural Development, Lansing, MI 48909, USA
| | - Mike Vanderklok
- Animal Industry Division, Michigan Department of Agriculture and Rural Development, Lansing, MI 48909, USA
| | - James J. Averill
- Animal Industry Division, Michigan Department of Agriculture and Rural Development, Lansing, MI 48909, USA
| | - Kurt C. VerCauteren
- National Wildlife Research Center, Animal and Plant Health Inspection Services, United States Department of Agriculture, 4101 LaPorte Ave, Fort Collins, CO 80521, USA
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Boon C, Dick T. How Mycobacterium tuberculosis goes to sleep: the dormancy survival regulator DosR a decade later. Future Microbiol 2012; 7:513-8. [PMID: 22439727 DOI: 10.2217/fmb.12.14] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
With 2 million deaths per year, TB remains the most significant bacterial killer. The long duration of chemotherapy and the large pool of latently infected people represent challenges in disease control. To develop drugs that effectively eradicate latent infection and shorten treatment duration, the pathophysiology of the causative agent Mycobacterium tuberculosis needs to be understood. The discovery that the tubercle bacillus can develop a drug-tolerant dormant form and the identification of the underlying genetic program 10 years ago paved the way for a deeper understanding of the life of the parasite inside human lesions and for new approaches to antimycobacterial drug discovery. Here, we summarize what we have learnt since the discovery of the master regulator of dormancy, DosR, and the key gaps in our knowledge that remain. Furthermore, we discuss a possible wider clinical relevance of DosR for 'nontuberculous mycobacteria'.
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Affiliation(s)
- Calvin Boon
- Dx Assays Pte Ltd, Woodlands Central Industrial Estate, 35 Marsiling Industrial Estate Road 3, Unit 02-03/02/01, 739257, Singapore
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Gupta A, Bhakta S. An integrated surrogate model for screening of drugs against Mycobacterium tuberculosis. J Antimicrob Chemother 2012; 67:1380-91. [PMID: 22398649 DOI: 10.1093/jac/dks056] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The intracellularly surviving and slow-growing pathogen, Mycobacterium tuberculosis, adapts the host cell environment for its active and dormant life cycle. It is evident that the lack of appropriate high-throughput screening of inhibitors within host cells is an impediment for the early stages of anti-tubercular drug discovery. We aimed to develop an integrated surrogate model that enhances the screening of large inhibitor libraries. METHODS Different mycobacterial species were compared for their growth, drug susceptibility and intracellular uptake. A 6-well plate solid agar-based spot culture growth inhibition (SPOTi) assay was developed into a higher throughput format. The uptake and intracellular survival of Mycobacterium aurum within mouse macrophage cells (RAW 264.7) were optimized using 24/96-well plate formats. RESULTS Fast-growing, non-pathogenic M. aurum was found to have an antibiotic-susceptibility profile similar to that of M. tuberculosis. The sensitivity to an acidic pH environment and the ability to multiply inside RAW 264.7 macrophages provided additional advantages for employing M. aurum in intracellular drug screening methods. A selection of anti-tubercular drugs inhibited the growth and viability of M. aurum inside the macrophages at different levels. CONCLUSIONS We present a rapid, convenient, high-throughput surrogate model, which provides a comprehensive evaluation platform for new chemical scaffolds against different physiological stages of mycobacteria within the primary cell environment of the host. The results using anti-tubercular drugs validate this model for screening libraries of existing and novel chemical entities.
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Affiliation(s)
- Antima Gupta
- Mycobacteria Research Laboratory, Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
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Yamano Y, Arai M, Kobayashi M. Neamphamide B, new cyclic depsipeptide, as an anti-dormant mycobacterial substance from a Japanese marine sponge of Neamphius sp. Bioorg Med Chem Lett 2012; 22:4877-81. [PMID: 22704240 DOI: 10.1016/j.bmcl.2012.05.071] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 05/03/2012] [Accepted: 05/07/2012] [Indexed: 11/25/2022]
Abstract
A new cyclic depsipeptide, designated neamphamide B (1), was isolated from a marine sponge of Neamphius sp. collected at Okinawa, Japan in 1993 as an anti-mycobacterial substance against active and dormant bacilli. The planar structure of neamphamide B (1) was determined on the basis of spectroscopic analysis, and stereostructure of amino acid was deduced by chromatographic comparison of the acid hydrolysate of 1 with appropriate amino acid standards after derivatizing with FDAA or GITC. Neamphamide B (1) showed potent anti-mycobacterial activity against Mycobacterium smegmatis under standard aerobic growth conditions as well as dormancy-inducing hypoxic conditions with MIC of 1.56 μg/mL. Neamphamide B (1) was also effective to Mycobacterium bovis BCG with MIC in the ranging of 6.25-12.5 μg/mL.
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Affiliation(s)
- Yoshi Yamano
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamada-oka 1-6, Suita, Osaka 565-0871, Japan
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40
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Pruksakorn P, Arai M, Liu L, Moodley P, Jacobs WR, Kobayashi M. Action-mechanism of trichoderin A, an anti-dormant mycobacterial aminolipopeptide from marine sponge-derived Trichoderma sp. Biol Pharm Bull 2012; 34:1287-90. [PMID: 21804219 DOI: 10.1248/bpb.34.1287] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the course of our search for anti-dormant mycobacterial substances from marine organisms, we previously isolated three new aminolipopeptides, named trichoderins A, A1 and B, from the culture of the marine sponge-derived fungus of Trichoderma sp. and determined their chemical structures. To identify the gene that could confer a resistance to trichoderin A, we prepared transformants of Mycobacterium (M.) smegmatis, which were transformed with the genomic DNA library of M. bovis BCG constructed in the multi-copy shuttle cosmid pYUB145. Then, the transformant of M. smegmatis, which over-expressed a part of genes that coded mycobacterial ATP synthase, was found to exhibit a resistance to trichoderin A. In addition, trichoderin A reduced ATP contents in M. bovis BCG. These findings elucidated that the anti-mycobacterial activity of trichoderins comes from the inhibition of ATP synthesis.
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Affiliation(s)
- Patamaporn Pruksakorn
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565–0871, Japan
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ald of Mycobacterium tuberculosis encodes both the alanine dehydrogenase and the putative glycine dehydrogenase. J Bacteriol 2011; 194:1045-54. [PMID: 22210765 DOI: 10.1128/jb.05914-11] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The putative glycine dehydrogenase of Mycobacterium tuberculosis catalyzes the reductive amination of glyoxylate to glycine but not the reverse reaction. The enzyme was purified and identified as the previously characterized alanine dehydrogenase. The Ald enzyme was expressed in Escherichia coli and had both pyruvate and glyoxylate aminating activities. The gene, ald, was inactivated in M. tuberculosis, which resulted in the loss of all activities. Both enzyme activities were found associated with the cell and were not detected in the extracellular filtrate. By using an anti-Ald antibody, the protein was localized to the cell membrane, with a smaller fraction in the cytosol. None was detected in the extracellular medium. The ald knockout strain grew without alanine or glycine and was able to utilize glycine but not alanine as a nitrogen source. Transcription of ald was induced when alanine was the sole nitrogen source, and higher levels of Ald enzyme were measured. Ald is proposed to have several functions, including ammonium incorporation and alanine breakdown.
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Khan A, Sarkar D. Nitrate reduction pathways in mycobacteria and their implications during latency. MICROBIOLOGY-SGM 2011; 158:301-307. [PMID: 22174380 DOI: 10.1099/mic.0.054759-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mycobacterial persistence has gained a lot of attention with respect to developing novel antitubercular drugs, which could drastically reduce the duration of tuberculosis (TB) therapy. A better understanding of the physiology of Mycobacterium tuberculosis, and of the metabolic state of the bacillus during the latent period, is a primary need in finding drug targets against persistent TB. Recent biochemical and genetic studies of nitrate reduction in mycobacteria have revealed the roles of distinct proteins and enzymes involved in the pathway. The differential degree of nitrate reduction among pathogenic and non-pathogenic mycobacterial species, and its regulation during oxygen and nutrient limitation, suggest a link between nitrate reduction pathways and latency. The respiratory and assimilatory reduction of nitrate in mycobacteria may be interconnected to facilitate rapid adaptation to changing oxygen and/or nitrogen conditions, increasing metabolic flexibility for survival in the hostile host environment. This review summarizes the nitrate metabolic pathways operative in mycobacteria to provide an insight into the mechanisms that M. tuberculosis has evolved to adapt successfully to the host environment.
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Affiliation(s)
- Arshad Khan
- Department of Pathology and Laboratory Medicine, University of Texas, Health Science Center at Houston, Medical School, Houston, TX 77030, USA
| | - Dhiman Sarkar
- Combi Chem-Bio Resource Center, National Chemical Laboratory, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
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Cordone A, Audrain B, Calabrese I, Euphrasie D, Reyrat JM. Characterization of a Mycobacterium smegmatis uvrA mutant impaired in dormancy induced by hypoxia and low carbon concentration. BMC Microbiol 2011; 11:231. [PMID: 22008214 PMCID: PMC3207969 DOI: 10.1186/1471-2180-11-231] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 10/18/2011] [Indexed: 11/25/2022] Open
Abstract
Background The aerobic fast-growing Mycobacterium smegmatis, like its slow-growing pathogenic counterpart Mycobacterium tuberculosis, has the ability to adapt to microaerobiosis by shifting from growth to a non-proliferating or dormant state. The molecular mechanism of dormancy is not fully understood and various hypotheses have been formulated to explain it. In this work, we open new insight in the knowledge of M. smegmatis dormancy, by identifying and characterizing genes involved in this behavior. Results In a library generated by transposon mutagenesis, we searched for M. smegmatis mutants unable to survive a coincident condition of hypoxia and low carbon content, two stress factors supposedly encountered in the host and inducing dormancy in tubercle bacilli. Two mutants were identified that mapped in the uvrA gene, coding for an essential component of the Nucleotide Excision Repair system (NER). The two mutants showed identical phenotypes, although the respective transposon insertions hit different regions of the uvrA gene. The restoration of the uvrA activity in M. smegmatis by complementation with the uvrA gene of M. tuberculosis, confirmed that i) uvrA inactivation was indeed responsible for the inability of M. smegmatis cells to enter or exit dormancy and, therefore, survive hypoxia and presence of low carbon and ii) showed that the respective uvrA genes of M. tuberculosis and M. smegmatis are true orthologs. The rate of survival of wild type, uvrA mutant and complemented strains under conditions of oxidative stress and UV irradiation was determined qualitatively and quantitatively. Conclusions Taken together our results confirm that the mycobacterial NER system is involved in adaptation to various stress conditions and suggest that cells with a compromised DNA repair system have an impaired dormancy behavior.
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Affiliation(s)
- Angela Cordone
- Dipartimento di Biologia Strutturale e Funzionale, Università Federico II di Napoli, Via Cinthia 4, 80126 Napoli, Italy.
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Mukherjee T, Boshoff H. Nitroimidazoles for the treatment of TB: past, present and future. Future Med Chem 2011; 3:1427-54. [PMID: 21879846 PMCID: PMC3225966 DOI: 10.4155/fmc.11.90] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Tuberculosis remains a leading cause of death resulting from an infectious agent, and the spread of multi- and extensively drug-resistant strains of Mycobacterium tuberculosis poses a threat to management of global health. New drugs that effectively shorten the duration of treatment and are active against drug-resistant strains of this pathogen are urgently required to develop effective chemotherapies to combat this disease. Two nitroimidazoles, PA-824 and OPC-67683, are currently in Phase II clinical trials for the treatment of TB and the outcome of these may determine the future directions of drug development for anti-tubercular nitroimidazoles. In this review we summarize the development of these nitroimidazoles and alternative analogs in these series that may offer attractive alternatives to PA-824 and OPC-67683 for further development in the drug-discovery pipeline. Lastly, the potential pitfalls in the development of nitroimidazoles as drugs for TB are discussed.
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Affiliation(s)
- Tathagata Mukherjee
- Tuberculosis Research Section, LCID, NIAID, NIH, Room 2W20G, Building 33, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Helena Boshoff
- Tuberculosis Research Section, LCID, NIAID, NIH, Room 2W20G, Building 33, 9000 Rockville Pike, Bethesda, MD 20892, USA
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DedA protein relates to action-mechanism of halicyclamine A, a marine spongean macrocyclic alkaloid, as an anti-dormant mycobacterial substance. Mar Drugs 2011; 9:984-993. [PMID: 21747743 PMCID: PMC3131556 DOI: 10.3390/md9060984] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/25/2011] [Accepted: 06/03/2011] [Indexed: 11/25/2022] Open
Abstract
A macrocyclic alkaloid, halicyclamine A, was re-discovered from an Indonesian marine sponge of Haliclona sp. 05A08 as an anti-dormant mycobacterial substance. To clarify action-mechanism of halicyclamine A, halicyclamine A-resistant strains were screened from the transformants of Mycobacterium smegmatis with the genomic DNA library of M. bovis BCG, which were constructed in the multi-copy shuttle cosmid pYUB145. Sequencing analysis of the cosmids isolated from the halicyclamine A-resistant transformants revealed that the responsible gene was involved in the genome region between 2920.549 kb and 2933.210 kb. Further experiments using the transformants over-expressing individual gene contained in the responsible region were executed, and the transformant, which over-expressed BCG2664 gene assigned as dedA gene, was found to become halicyclamine A-resistant. This evidence strongly suggested that DedA protein correlates with the action-mechanism of halicyclamine A as an anti-dormant mycobacterial substance.
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Abstract
Tools for effective TB control have been available for years. Case finding, active medications, case management and directly observed therapy are the foundations for the management of TB. The current TB epidemic, centered in resource-limited settings is fueled by the HIV-1 epidemic. Lack of ability to diagnose and treat drug-resistant TB has led to development of more extensive patterns of resistance. Among the currently available drugs, there is reason to hope that rifamycins paired with fluoroquinolones will lead to shorter treatment regimens for drug-susceptible TB. As the result of novel public-private collaborations and investments of resources, new drugs are being developed. These include TMC207, already shown to have activity early in the treatment of multidrug-resistant TB and others that are likely to be active against persistor organisms, and have the prospect to dramatically shorten treatment courses for active and latent TB. Given that these drugs have novel mechanisms of action, combinations have the prospect to be highly active even against multidrug-resistant organisms.
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Affiliation(s)
- Eric Leibert
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, 550 1st Avenue, New York, NY 10016, USA.
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Dick T, Manjunatha U, Kappes B, Gengenbacher M. Vitamin B6 biosynthesis is essential for survival and virulence of Mycobacterium tuberculosis. Mol Microbiol 2010; 78:980-8. [PMID: 20815826 DOI: 10.1111/j.1365-2958.2010.07381.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
With 500000 cases of multidrug-resistant tuberculosis there is an urgent need for attractive targets to enable the discovery of novel antimycobacterials. The biosynthesis of essential cofactors is of particular interest as these pathways are absent in man and their inhibition is expected to affect the metabolism of Mycobacterium tuberculosis at multiple sites. Our data demonstrate that the pathogen synthesizes pyridoxal 5-phosphate (PLP), the bioactive form of vitamin B6, by a heteromeric PLP synthase composed of Pdx1 (Rv2606c) and Pdx2 (Rv2604c). Disruption of the pdx1 gene generated a strictly B6 auxotrophic M. tuberculosis mutant, Δpdx1. Removal of the cofactor during exponential growth or stationary phase demonstrated the essentiality of vitamin B6 biosynthesis for growth and survival of the pathogen in culture. In a tuberculosis dormancy model based on gradual oxygen depletion, de novo biosynthesis of PLP was required for regrowth of the bacillus after direct oxygen exposure. The Δpdx1 mutant showed a severe growth defect in immunocompetent mice: bacilli applied intranasally failed to persist in host tissues and were quickly cleared. We conclude that vitamin B6 biosynthesis is required for survival of M. tuberculosis in vivo and thus might represent a candidate pathway for the development of new antitubercular agents.
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Affiliation(s)
- Thomas Dick
- Novartis Institute for Tropical Diseases Pte. Ltd., 10 Biopolis Road, #05-01 Chromos, Singapore 138670, Singapore
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Shi C, Chen L, Chen Z, Zhang Y, Zhou Z, Lu J, Fu R, Wang C, Fang Z, Fan X. Enhanced protection against tuberculosis by vaccination with recombinant BCG over-expressing HspX protein. Vaccine 2010; 28:5237-44. [DOI: 10.1016/j.vaccine.2010.05.063] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 05/06/2010] [Accepted: 05/26/2010] [Indexed: 11/16/2022]
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Pruksakorn P, Arai M, Kotoku N, Vilchèze C, Baughn AD, Moodley P, Jacobs WR, Kobayashi M. Trichoderins, novel aminolipopeptides from a marine sponge-derived Trichoderma sp., are active against dormant mycobacteria. Bioorg Med Chem Lett 2010; 20:3658-63. [PMID: 20483615 DOI: 10.1016/j.bmcl.2010.04.100] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/17/2010] [Accepted: 04/21/2010] [Indexed: 11/30/2022]
Abstract
Three new aminolipopeptides, designated trichoderins A (1), A1 (2), and B (3), were isolated from a culture of marine sponge-derived fungus of Trichoderma sp. as anti-mycobacterial substances with activity against active and dormant bacilli. The chemical structures of trichoderins were determined on the basis of spectroscopic study. Trichoderins showed potent anti-mycobacterial activity against Mycobacterium smegmatis, Mycobacterium bovis BCG, and Mycobacterium tuberculosis H37Rv under standard aerobic growth conditions as well as dormancy-inducing hypoxic conditions, with MIC values in the range of 0.02-2.0 microg/mL.
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