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https://www.readbyqxmd.com/read/28812125/recombinant-expression-and-biochemical-characterization-of-mycobacterium-tuberculosis-3fe-4s-ferredoxin-rv1786
#1
Yun Lu, Feng Qiao, Yue Li, Xiao-Hong Sang, Cong-Ran Li, Jian-Dong Jiang, Xin-Yi Yang, Xue-Fu You
Ferredoxins are iron-sulfur protein that mediate electron transfer in cytochrome P450 mono-oxygenase (CYP)-related catalytic reactions in a wide variety of organisms. Rv1786 is a putative ferredoxin, encoded by a gene located downstream of the gene encoding CYP143A1 in the Mycobacterium tuberculosis genome. However, the structure and function of Rv1786 have remained unclear. Here, the recombinant Mtb Rv1786 was expressed, purified as a His-tagged form and characterized with [3Fe-4S] clusters as its cofactors using a series of measurements including SDS-PAGE, western blot, UV/Visible, MALDI-TOF/TOF-MS, and electron paramagnetic resonance spectroscopic analysis...
August 15, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28811607/localized-iron-accumulation-precedes-nucleation-and-growth-of-magnetite-crystals-in-magnetotactic-bacteria
#2
Jacques Werckmann, Jefferson Cypriano, Christopher T Lefèvre, Kassiogé Dembelé, Ovidiu Ersen, Dennis A Bazylinski, Ulysses Lins, Marcos Farina
Many magnetotactic bacteria (MTB) biomineralize magnetite crystals that nucleate and grow inside intracellular membranous vesicles that originate from invaginations of the cytoplasmic membrane. The crystals together with their surrounding membranes are referred to magnetosomes. Magnetosome magnetite crystals nucleate and grow using iron transported inside the vesicle by specific proteins. Here we address the question: can iron transported inside MTB for the production of magnetite crystals be spatially mapped using electron microscopy? Cultured and uncultured MTB from brackish and freshwater lagoons were studied using analytical transmission electron microscopy in an attempt to answer this question...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28808382/allium-sativum-constituents-exhibit-anti-tubercular-activity-in-vitro-and-in-raw-264-7-mouse-macrophage-cells-infected-with-mycobacterium-tuberculosis-h37rv
#3
Swapna S Nair, Sujay S Gaikwad, Savita P Kulkarni, Alka Pravin Mukne
BACKGROUND: Long duration of treatment, side-effects of currently used anti-tubercular drugs and emergence of drug-resistant forms of Mycobacterium tuberculosis (MTB) warrants the need to develop new drugs to tackle the scourge of tuberculosis (TB). Garlic is an edible plant reported to have anti-tubercular activity. However, previous researches on anti-tubercular effect of garlic were focused mostly on preliminary in vitro screening. OBJECTIVE: To identify constituents responsible for anti-tubercular activity of thiosulfinate-derivative rich extract of garlic (GE) and to evaluate activity of the most active constituent in RAW 264...
July 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28806423/new-synthetic-lipid-antigens-for-rapid-serological-diagnosis-of-tuberculosis
#4
Alison Jones, Mark Pitts, Juma'a R Al Dulayymi, James Gibbons, Andrew Ramsay, Delia Goletti, Christopher D Gwenin, Mark S Baird
BACKGROUND: During pulmonary tuberculosis (PTB) antibodies are generated to trehalose esters of mycolic acids which are cell wall lipids of Mycobacterium tuberculosis (Mtb). Attempts have been made to use these complex natural mixtures in serological tests for PTB diagnosis. AIM: The aim of this work was to determine whether a serological test based on a panel of defined individual trehalose esters of characteristic synthetic mycolic acids has improved diagnostic accuracy in distinguishing patients with culture positive PTB from individuals who were Mtb culture negative...
2017: PloS One
https://www.readbyqxmd.com/read/28803470/effect-of-dmso-on-protein-structure-and-interactions-assessed-by-collision-induced-dissociation-and-unfolding
#5
Daniel S-H Chan, Madeline E Eve Kavanagh, Kirsty J McLean, Andrew William Munro, Dijana Matak-Vinkovic, Anthony G Coyne, Chris Abell
Native mass spectrometry is an ideal technique to investigate the effects of DMSO on protein structure and interac-tions. Given the frequent use of DMSO in biochemical and biophysical assays, it is desirable to understand the influence of DMSO concentration on the dissociation or unfolding behavior of proteins. In this study, the effects of DMSO on the structure and interac-tions of avidin and Mycobacterium tuberculosis (Mtb) CYP142A1 were assessed through collision-induced dissociation (CID) and collision-induced unfolding (CIU) as monitored by nanoelectrospray ionization-ion mobility-mass spectrometry (nESI-IM-MS)...
August 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28802411/the-minipig-as-an-animal-model-to-study-mycobacterium-tuberculosis-infection-and-natural-transmission
#6
Laylaa Ramos, Andres Obregon-Henao, Marcela Henao-Tamayo, Richard Bowen, Joan K Lunney, Mercedes Gonzalez-Juarrero
In endemic countries more than 20% of tuberculosis (TB) cases are in infants and children. Current animal models study TB during adulthood but animal models for infant TB are scarce. Here we propose that minipigs can be used as an animal model to study adult, adolescent and infant TB including natural transmission. In these studies, two-month old minipigs (representing infant age in humans) and six-month old minipigs (representing adolescence in humans) were infected via the aerosol route with hyper-virulent clinical strain W-Beijing Mycobacterium tuberculosis (Mtb) HN878 and were monitored for 11 or 36 weeks post-challenge, respectively...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802408/down-regulation-of-malate-synthase-in-mycobacterium-tuberculosis-h37ra-leads-to-reduced-stress-tolerance-persistence-and-survival-in-macrophages
#7
Kumar Sachin Singh, Rishabh Sharma, Deepa Keshari, Nirbhay Singh, Sudheer Kumar Singh
Malate synthase is a condensing enzyme responsible for conversion of glyoxylate to malate in the presence of acetyl-CoA. This reaction helps in bypassing the TCA cycle reactions involving carbon loss and leads to diverting some of the carbon skeletons to gluconeogenic events while rest can continue to provide TCA cycle intermediates. Malate synthase (GlcB) is encoded by MRA_1848 of Mycobacterium tuberculosis H37Ra (Mtb-Ra). We developed a knockdown (KD) Mtb-Ra strain by down-regulating GlcB. The survival studies suggested increased susceptibility to oxidative and nitrosative stress as well as to rifampicin...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802407/immunological-characterization-of-latent-tuberculosis-infection-in-a-low-endemic-country
#8
Roelof A de Paus, Krista E van Meijgaarden, Corine Prins, Margreet H Kamphorst, Sandra M Arend, Tom H M Ottenhoff, Simone A Joosten
The diagnosis of a latent tuberculosis infection (LTBI) is based on detection of immunity against Mycobacterium tuberculosis (Mtb). The tuberculin skin test (TST), the Quantiferon (QFT) and a prolonged lymphocyte stimulation test using either ESAT-6/CFP-10 (LST-EC) or PPD (LST-PPD) were evaluated in a cohort of 495 individuals, suspected to have LTBI, in a low endemic country. While the TST and LST-PPD were both positive in the majority (75%) of individuals, only one third responded in the LST-EC and in the QFT...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802405/detection-of-mycobacterium-tuberculosis-from-paraffin-embedded-tissues-by-genexpert-mtb-rif
#9
Laura Rindi, Greta Alì, Barbara Fabiani, Gabriella Fontanini, Carlo Garzelli
GeneXpert MTB/RIF (Xpert) assay, a rapid and automated system based on real-time PCR and molecular beacon technology, proved to be a sensitive and specific tool capable of detecting Mycobacterium tuberculosis and rifampin resistance in clinical specimens. In this study we provide a Xpert-dedicated successful protocol for processing paraffin-embedded tissue and assess the feasibility of the Xpert assay-based tuberculosis (TB) diagnosis on these specimens, thus proving the Xpert assay as a valuable TB diagnostic tool in supporting conventional histopathological methods...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802401/differences-in-igg-responses-against-infection-phase-related-mycobacterium-tuberculosis-mtb-specific-antigens-in-individuals-exposed-or-not-to-mtb-correlate-with-control-of-tb-infection-and-progression
#10
Mariateresa Coppola, Leonar Arroyo, Krista E van Meijgaarden, Kees Lmc Franken, Annemieke Geluk, Luis F Barrera, Tom H M Ottenhoff
Tuberculosis (TB) occurs in only 3-10% of Mycobacterium tuberculosis (Mtb) infected individuals, suggesting that natural immunity can contain Mtb infection, although this remains poorly understood. Next to T-cells, a potentially protective role for B-cells and antibodies has emerged recently. However, the Mtb antigens involved remain ill-defined. Here, we investigated in a TB-endemic setting IgG levels against 15 Mtb antigens, representing various phases of Mtb infection and known to be potent human T-cell antigens...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28802397/lysx-gene-is-differentially-expressed-among-mycobacterium-tuberculosis-strains-with-different-levels-of-virulence
#11
Alejandra Montoya-Rosales, Roberta Provvedi, Flor Torres-Juarez, Jose A Enciso-Moreno, Rogelio Hernandez-Pando, Riccardo Manganelli, Bruno Rivas-Santiago
Antimicrobial peptides (AMPs) are mainly produced by epithelial cells and macrophages to eliminate infecting mycobacteria through direct antimicrobial activity and immunomodulation. Indeed, it has been described that this line of defense is essential to control infection. However, Mycobacterium tuberculosis (Mtb) has developed mechanisms to avoid AMPs activity, for instance lysX adds lysine residues to surface phospholipids changing their net charge, leading to the repelling of the AMPs. In the present study, we determined that lysX gene is differentially expressed among Mtb strains...
September 2017: Tuberculosis
https://www.readbyqxmd.com/read/28795999/the-utility-of-immunohistochemistry-in-mycobacterial-infection-a-proposal-for-multimodality-testing
#12
Isaac H Solomon, Melanie E Johncilla, Jason L Hornick, Danny A Milner
Mycobacterium species are slow growing bacteria that cause significant morbidity and mortality worldwide. Because of the relative rarity of mycobacterial infections, potential for detection of nonpathogenic environmental contaminants, and substantial costs associated with molecular diagnostics, effective screening methods are needed to identify samples most suitable for molecular testing. While anatomic pathology specimens can be utilized to identify characteristic histologic inflammatory patterns and to directly visualize mycobacteria through histochemical (acid fast bacilli [AFB]) stains, the utility of immunohistochemistry (IHC) in this setting is unknown...
August 8, 2017: American Journal of Surgical Pathology
https://www.readbyqxmd.com/read/28794886/evaluation-of-genexpert-mtb-rif-for-determination-of-rifampicin-resistance-among-new-tuberculosis-cases-in-west-and-northwest-iran
#13
S Atashi, B Izadi, S Jalilian, S H Madani, A Farahani, P Mohajeri
Despite a Mycobacterium tuberculosis control programme and anti-tuberculosis drugs, drug-resistant tuberculosis (DR-TB) is one of the most serious public health issues worldwide. Rapid laboratory diagnosis of M. tuberculosis is needed for the diagnosis of multidrug-resistant (MDR) TB and to find the optimal treatment protocol. The purpose of this study was to detect resistance to rifampicin in new cases of TB using the GeneXpert MTB/RIF (M. tuberculosis/rifampicin) assay and the standard proportional method in west and northwest Iran...
September 2017: New Microbes and New Infections
https://www.readbyqxmd.com/read/28794178/potential-of-high-affinity-slow-off-rate-modified-aptamer-somamer-reagents-for-mycobacterium-tuberculosis-proteins-as-tools-for-infection-models-and-diagnostic-applications
#14
Theresa Russell, Louis S Green, Taylor Rice, Nicole A Kruh-Garcia, Karen Dobos, Mary A DeGroote, Thomas Hraha, David G Sterling, Nebojsa Janjic, Urs A Ochsner
Direct pathogen detection in blood to diagnose active tuberculosis (TB) has been difficult, due to low levels of circulating antigens or due to the lack of specific, high-affinity binding reagents and reliable assays with adequate sensitivity. We sought to determine whether slow off-rate modified aptamer (SOMAmer) reagents with sub-nanomolar affinity for M. tuberculosis (Mtb) proteins (antigen 85A, 85B, 85C, GroES, GroEL2, DnaK, CFP10, KAD, CFP2, RplL and Tpx) could be useful to diagnose tuberculosis. When incorporated into the multiplexed, array-based proteomic SOMAscan assay, limits of detection reached the sub-picomolar range in 40% serum...
August 9, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28791878/role-of-ergothioneine-in-microbial-physiology-and-pathogenesis
#15
Bridgette M Cumming, Krishna C Chinta, Vineel P Reddy, Adrie Jc Steyn
SIGNIFICANCE: L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria and some fungi. In contrast to other low molecular weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables survival of the microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection...
August 9, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28789944/prioritization-of-natural-compounds-against-mycobacterium-tuberculosis-3-dehydroquinate-dehydratase-a-combined-in-silico-and-in-vitro-study
#16
Mohsin Y Lone, Mohd Athar, Vivek K Gupta, Prakash C Jha
Enormous efforts have been endeavored to develop inhibitors against the potential therapeutic target, mycobacterium tuberculosis 3-dehydroquinate dehydratase (MtbDHQase) to combat resistance. Over a dozen of small molecules have been crystallized to characterize the structural basis of the inhibition. However, the studies accomplished so far, have not incorporated all the essential interactions of these complexes simultaneously, to identify the novel inhibitors. Therefore, an attempt was made to construct the pharmacophore models and identify the essential features that can be employed to prioritize the molecules against this target...
August 5, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28783093/impact-of-larger-sputum-volume-on-xpert-%C3%A2-mtb-rif-assay-detection-of-mycobacterium-tuberculosis-in-smear-negative-individuals-with-suspected-tuberculosis
#17
Sharlaa Badal-Faesen, Cynthia Firnhaber, Michelle A Kendall, Xingye Wu, Beatriz Grinsztejn, Rodrigo Otavio da Silva Escada, Michel Fernandez, Evelyn Hogg, Ian Sanne, Pamela Johnson, David Alland, Gerald H Mazurek, Debra A Benator, Anne F Luetkemeyer
As a strategy to improve the sensitivity of nucleic acid-based testing in acid-fast bacilli (AFB) negative samples, larger volumes of sputum (5-10 mL) were tested with Xpert(®) MTB/RIF from 176 individuals with smear-negative sputum undergoing tuberculosis evaluation. Despite larger volumes, this strategy had a suboptimal sensitivity of 50% (4/8).
August 7, 2017: Journal of Clinical Medicine
https://www.readbyqxmd.com/read/28782605/drug-adherence-and-efficacy-of-smear-microscopy-in-the-diagnosis-of-pulmonary-tuberculosis-after-2-months-of-medication-in-north-western-tanzania
#18
Benson R Kidenya, Stephen E Mshana, Lisa Gerwing-Adima, Jeremiah Kidola, Christa Kasang
OBJECTIVES: The study aimed at assessing the Tuberculosis (TB) medication adherence level and the efficacy of smear microscopy in the diagnosing pulmonary TB at month 2. METHODS: A prospective study was conducted at the four sites located in the Northern-western Tanzania. New smear positive, pulmonary TB patients were followed up and their adherence to TB medication assessed after 2 months of the treatment. In addition, the acid fast bacilli (AFB) smear microscopy was performed after 2 and 5 months of the treatment...
August 3, 2017: International Journal of Infectious Diseases: IJID
https://www.readbyqxmd.com/read/28782049/asymmetric-structure-of-the-dimerization-domain-of-phor-a-sensor-kinase-important-for-the-virulence-of-mycobacterium-tuberculosis
#19
Daniel Xing, Michelle B Ryndak, Liqin Wang, Irina Kolesnikova, Issar Smith, Shuishu Wang
The PhoP-PhoR two-component system is essential for the virulence of Mycobacterium tuberculosis (Mtb) and therefore represents a potential target for developing novel antituberculosis therapies. However, little is known about the mechanism by which this two-component system regulates the virulence. In this study, we demonstrated that a phoR mutant Mtb strain has phenotypes similar to those of a phoP mutant, suggesting that PhoP and PhoR work in the same pathway to regulate Mtb virulence. We determined the structure of the dimerization and histidine phosphotransfer (DHp) domain of PhoR to a 1...
July 31, 2017: ACS Omega
https://www.readbyqxmd.com/read/28781126/targeting-mycobacterium-tuberculosis-sensitivity-to-thiol-stress-at-acidic-ph-kills-the-bacterium-and-potentiates-antibiotics
#20
Garry B Coulson, Benjamin K Johnson, Huiqing Zheng, Christopher J Colvin, Robert J Fillinger, Elizabeth R Haiderer, Neal D Hammer, Robert B Abramovitch
Mycobacterium tuberculosis (Mtb) must sense and adapt to immune pressures such as acidic pH during pathogenesis. The goal of this study was to isolate compounds that inhibit acidic pH resistance, thus defining virulence pathways that are vulnerable to chemotherapy. Here, we report that the compound AC2P36 selectively kills Mtb at acidic pH and potentiates the bactericidal activity of isoniazid, clofazimine, and diamide. We show that AC2P36 activity is associated with thiol stress and causes an enhanced accumulation of intracellular reactive oxygen species at acidic pH...
July 17, 2017: Cell Chemical Biology
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