के विकास माइकोबैक्टीरियम क्षयरोग Biofilms
Summary
माइकोबैक्टीरियम क्षयरोग दवा सहिष्णु biofilms रूपों जब कुछ शर्तों में सभ्य. यहाँ हम संवर्धन एम. के लिए विधियों का वर्णन तपेदिक biofilms और दवा सहिष्णु persisters की आवृत्ति का निर्धारण. इन प्रोटोकॉल आगे के अध्ययन के लिए उपयोगी दवा सहिष्णुता में एम. के तंत्र में हो जाएगा तपेदिक.
Abstract
Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, has an extraordinary ability to survive against environmental stresses including antibiotics. Although stress tolerance of M. tuberculosis is one of the likely contributors to the 6-month long chemotherapy of tuberculosis 1, the molecular mechanisms underlying this characteristic phenotype of the pathogen remain unclear. Many microbial species have evolved to survive in stressful environments by self-assembling in highly organized, surface attached, and matrix encapsulated structures called biofilms 2-4. Growth in communities appears to be a preferred survival strategy of microbes, and is achieved through genetic components that regulate surface attachment, intercellular communications, and synthesis of extracellular polymeric substances (EPS) 5,6. The tolerance to environmental stress is likely facilitated by EPS, and perhaps by the physiological adaptation of individual bacilli to heterogeneous microenvironments within the complex architecture of biofilms 7.
In a series of recent papers we established that M. tuberculosis and Mycobacterium smegmatis have a strong propensity to grow in organized multicellular structures, called biofilms, which can tolerate more than 50 times the minimal inhibitory concentrations of the anti-tuberculosis drugs isoniazid and rifampicin 8-10. M. tuberculosis, however, intriguingly requires specific conditions to form mature biofilms, in particular 9:1 ratio of headspace: media as well as limited exchange of air with the atmosphere 9. Requirements of specialized environmental conditions could possibly be linked to the fact that M. tuberculosis is an obligate human pathogen and thus has adapted to tissue environments. In this publication we demonstrate methods for culturing M. tuberculosis biofilms in a bottle and a 12-well plate format, which is convenient for bacteriological as well as genetic studies. We have described the protocol for an attenuated strain of M. tuberculosis, mc27000, with deletion in the two loci, panCD and RD1, that are critical for in vivo growth of the pathogen 9. This strain can be safely used in a BSL-2 containment for understanding the basic biology of the tuberculosis pathogen thus avoiding the requirement of an expensive BSL-3 facility. The method can be extended, with appropriate modification in media, to grow biofilm of other culturable mycobacterial species.
Overall, a uniform protocol of culturing mycobacterial biofilms will help the investigators interested in studying the basic resilient characteristics of mycobacteria. In addition, a clear and concise method of growing mycobacterial biofilms will also help the clinical and pharmaceutical investigators to test the efficacy of a potential drug.
Protocol
Discussion
तपेदिक (टीबी), माइकोबैक्टीरियम क्षयरोग के संक्रमण की वजह से वैश्विक सार्वजनिक स्वास्थ्य के लिए एक बड़ा खतरा बनी हुई है. दुनिया की आबादी का लगभग एक तिहाई asymptomatically रोगज़नक़ द्वारा संक्रमित होने का अनुम?…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
काम से बाहर स्वास्थ्य और अमेरिकी फेफड़े एसोसिएशन के राष्ट्रीय संस्थान से वित्तीय सहायता के साथ किया गया.
Materials
| Equipment and supplies | SUPPLIER | CATALOG NUMBER |
| Incubator | VWR | Model # 1923/25 |
| Polystyrene culture bottles | Fisher Scientific | 03-374-300 |
| 12-well tissue culture plate | VWR | 62406-165 |
| 50-mL conical tubes | VWR | 89039-660 |
| Rocker | Thermo Scientific | 57019-662 |
| Chromatographic refrigerator | VWR | 55702-520 |
| petri dish | VWR | 25384-342 |
| REAGENT | SUPPLIER | CATALOG NUMBER |
| KH2PO4 (monobasic) | EMD | PX1565-1 |
| MgSO4 | Fisher | M65-500 |
| L-asparagine | Sigma | A4284-100G |
| citric acid | Sigma | C1857-100G |
| ferric ammonium citrate | Sigma | F5879-100G |
| glycerol | EMD | GX0185-5 |
| NaOH | Sigma | S8045-500G |
| ZnSO4 | Sigma | Z4750-500G |
| D-pantothenic acid | Sigma | P2250-25G |
| Difco Middlebrook 7H9 Broth | Becton Dickinson | 271310 |
| Middlebrook OADC Enrichment | BBL | 212351 |
| Tween-80 | Fisher | T164-500 |
| 250mL storage bottle | Corning | 430281 |
| 12 well plates | Falcon (BD) | 353043 |
| rifampicin | Sigma | R3501-1G |
| methanol | J.T. Baker | 9070-05 |
| 10mlLsyringe | Becton Dickinson | 301604 |
| 1-200μL pipet tips | VWR | 89079-458 |
| parafilm M | VWR | PM-996 |
| 15mL centrifuge tube | Greiner Bio-One | 188-285 |
| Difco Mycobacteria 7H11 Agar | Becton Dickinson | 283810 |
| NaCl | Fisher | BP358-1 |
| KCl | Sigma | P9333-500G |
| Na2HPO4 (dibasic) | Sigma | S0876-500G |
Riferimenti
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