scholarly journals Analysis of rpoB and pncA mutations in the published literature: an insight into the role of oxidative stress in Mycobacterium tuberculosis evolution?

2005 ◽  
Vol 55 (5) ◽  
pp. 674-679 ◽  
Author(s):  
Denise M. O'Sullivan ◽  
Timothy D. McHugh ◽  
Stephen H. Gillespie
Microbiology ◽  
2014 ◽  
Vol 160 (9) ◽  
pp. 1821-1831 ◽  
Author(s):  
Viveshree S. Govender ◽  
Saiyur Ramsugit ◽  
Manormoney Pillay

Adhesion to host cells is a precursor to host colonization and evasion of the host immune response. Conversely, it triggers the induction of the immune response, a process vital to the host’s defence against infection. Adhesins are microbial cell surface molecules or structures that mediate the attachment of the microbe to host cells and thus the host–pathogen interaction. They also play a crucial role in bacterial aggregation and biofilm formation. In this review, we discuss the role of adhesins in the pathogenesis of the aetiological agent of tuberculosis, Mycobacterium tuberculosis. We also provide insight into the structure and characteristics of some of the characterized and putative M. tuberculosis adhesins. Finally, we examine the potential of adhesins as targets for the development of tuberculosis control strategies.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander V. Maksimenko

Undiminishing actuality of enzyme modification for therapeutic purposes has been confirmed by application of modified enzymes in clinical practice and numerous research data on them. Intravenous injection of the superoxide dismutase-chondroitin sulfate-catalase (SOD-CHS-CAT) conjugate in preventive and medicative regimes in rats with endotoxin shock induced with a lipopolysaccharide bolus has demonstrated that antioxidant agents not only effectively prevent damage caused by oxidative stress (as believed previously) but also can be used for antioxidative stress therapy. The results obtained emphasize the importance of investigation into the pathogenesis of vascular damage and the role of oxidative stress in it. The effects of intravenous medicative injection of SOD-CHS-CAT in a rat model of endotoxin shock have demonstrated a variety in the activity of this conjugate in addition to prevention of NO conversion in peroxynitrite upon interaction withO2∙-superoxide radical. Together with the literature data, these findings offer a prospect for the study of NO-independent therapeutic effects of SOD-CHS-CAT, implying the importance of a better insight into the mechanisms of the conjugate activity in modeled cardiovascular damage involving vasoactive agents other than NO.


2020 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
Resti Yudhawati ◽  
Nitya Prasanta

Pulmonary Tuberculosis is a chronic infection that caused by Mycobacterium tuberculosis (M.tb) infection and it is still the major health problem worldwide. Mycobacterium tuberculosis infection can induce oxidative stress. Some studies has proved that active TB patients have an association with excessive oxidative stress which causes glutathione (GSH) level decrease and free radicals increase. Glutathione (GSH) facilitates the control of M.TB intracellular bacterial growth in macrophages and has direct antimicrobial activity.  N-acetylcysteine (NAC) is thiol, a precursor of L-cysteine and glutathione synthesis (GSH) that has been used for decades as a mucolytic agent in the treatment of respiratory diseases. Some studies report beneficial role of NAC as immunomodulator, besides NAC also has anti-inflammatory and antimicrobial effect in TB management.


2009 ◽  
Vol 77 (6) ◽  
pp. 2557-2567 ◽  
Author(s):  
Suat L. G. Cirillo ◽  
Selvakumar Subbian ◽  
Bing Chen ◽  
Torin R. Weisbrod ◽  
William R. Jacobs ◽  
...  

ABSTRACT Persistence of Mycobacterium tuberculosis in humans represents a major roadblock to elimination of tuberculosis. We describe identification of a locus in M. tuberculosis, mel2, that displays similarity to bacterial bioluminescent loci and plays an important role during persistence in mice. We constructed a deletion of the mel2 locus and found that the mutant displays increased susceptibility to reactive oxygen species (ROS). Upon infection of mice by aerosol the mutant grows normally until the persistent stage, where it does not persist as well as wild type. Histopathological analyses show that infection with the mel2 mutant results in reduced pathology and both CFU and histopathology indicate that dissemination of the mel2 mutant to the spleen is delayed. These data along with growth in activated macrophages and infection of Phox−/− and iNOS−/− mice and bone marrow-derived macrophages suggest that the primary mechanism by which mel2 affects pathogenesis is through its ability to confer resistance to ROS. These studies provide the first insight into the mechanism of action for this novel class of genes that are related to bioluminescence genes. The role of mel2 in resistance to ROS is important for persistence and dissemination of M. tuberculosis and suggests that homologues in other bacterial species are likely to play a role in pathogenesis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jakub Pawełczyk ◽  
Anna Brzostek ◽  
Alina Minias ◽  
Przemysław Płociński ◽  
Anna Rumijowska-Galewicz ◽  
...  

AbstractMycobacterium tuberculosis (Mtb) is an obligate human pathogen that can adapt to the various nutrients available during its life cycle. However, in the nutritionally stringent environment of the macrophage phagolysosome, Mtb relies mainly on cholesterol. In previous studies, we demonstrated that Mtb can accumulate and utilize cholesterol as the sole carbon source. However, a growing body of evidence suggests that a lipid-rich environment may have a much broader impact on the pathogenesis of Mtb infection than previously thought. Therefore, we applied high-resolution transcriptome profiling and the construction of various mutants to explore in detail the global effect of cholesterol on the tubercle bacillus metabolism. The results allow re-establishing the complete list of genes potentially involved in cholesterol breakdown. Moreover, we identified the modulatory effect of vitamin B12 on Mtb transcriptome and the novel function of cobalamin in cholesterol metabolite dissipation which explains the probable role of B12 in Mtb virulence. Finally, we demonstrate that a key role of cholesterol in mycobacterial metabolism is not only providing carbon and energy but involves also a transcriptome remodeling program that helps in developing tolerance to the unfavorable host cell environment far before specific stress-inducing phagosomal signals occur.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
K. Manasa ◽  
R. Vani

Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS) is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platelets were stored for 12 days at 22°C. OS markers such as aggregation, superoxides, reactive oxygen species, glucose, pH, lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed. OS increased during storage as indicated by increments in aggregation, superoxides, pH, conjugate dienes, and superoxide dismutase and decrements in glucose and catalase. Thus, platelets could endure OS till 6 days during storage, due to the antioxidant defense system. An evident increase in OS was observed from day 8 of storage, which can diminish the platelet efficacy. The present study provides an insight into the gradual changes occurring during platelet storage. This lays the foundation towards new possibilities of employing various antioxidants as additives in storage solutions.


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