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Photodiagnosis and Photodynamic Therapy Feb 2024
PubMed: 38118372
DOI: 10.1016/j.pdpdt.2023.103909 -
Molecular Microbiology Mar 2024The infection course of Mycobacterium tuberculosis is highly dynamic and comprises sequential stages that require damaging and crossing of several membranes to enable...
The infection course of Mycobacterium tuberculosis is highly dynamic and comprises sequential stages that require damaging and crossing of several membranes to enable the translocation of the bacteria into the cytosol or their escape from the host. Many important breakthroughs such as the restriction of mycobacteria by the autophagy pathway and the recruitment of sophisticated host repair machineries to the Mycobacterium-containing vacuole have been gained in the Dictyostelium discoideum/M. marinum system. Despite the availability of well-established light and advanced electron microscopy techniques in this system, a correlative approach integrating both methods with near-native ultrastructural preservation is currently lacking. This is most likely due to the low ability of D. discoideum to adhere to surfaces, which results in cell loss even after fixation. To address this problem, we improved the adhesion of cells and developed a straightforward and convenient workflow for 3D-correlative light and electron microscopy. This approach includes high-pressure freezing, which is an excellent technique for preserving membranes. Thus, our method allows to monitor the ultrastructural aspects of vacuole escape which is of central importance for the survival and dissemination of bacterial pathogens.
Topics: Dictyostelium; Mycobacterium marinum; Freezing; Mycobacterium; Microscopy, Electron
PubMed: 38063129
DOI: 10.1111/mmi.15205 -
Heliyon Nov 2023A series of triclosan azo-adducts were synthesized to investigate their structure-activity relationship against and non-tuberculous mycobacteria. The series' most...
A series of triclosan azo-adducts were synthesized to investigate their structure-activity relationship against and non-tuberculous mycobacteria. The series' most potent compound was four and sixteen times more active than triclosan and rifabutin against drug-resistant , respectively, while being less cytotoxic to human macrophages than triclosan on day one. Additionally, one of the azo-adducts was twice as efficient against as triclosan and twice as effective against as isoniazid. Furthermore, the synthesized azo-adducts were equally effective against strains overexpressing InhA, suggesting that these compounds work through a distinct mechanism.
PubMed: 38034623
DOI: 10.1016/j.heliyon.2023.e22182 -
Journal of Leukocyte Biology Feb 2024Because granulomas are a hallmark of tuberculosis pathogenesis, the study of the dynamic changes in their cellular composition and morphological character can facilitate...
Because granulomas are a hallmark of tuberculosis pathogenesis, the study of the dynamic changes in their cellular composition and morphological character can facilitate our understanding of tuberculosis pathogenicity. Adult zebrafish infected with Mycobacterium marinum form granulomas that are similar to the granulomas in human patients with tuberculosis and therefore have been used to study host-mycobacterium interactions. Most studies of zebrafish granulomas, however, have focused on necrotic granulomas, while a systematic description of the different stages of granuloma formation in the zebrafish model is lacking. Here, we characterized the stages of granulomas in M. marinum-infected zebrafish, including early immune cell infiltration, nonnecrotizing granulomas, and necrotizing granulomas, using corresponding samples from patients with pulmonary tuberculosis as references. We combined hematoxylin and eosin staining and in situ hybridization to identify the different immune cell types and follow their spatial distribution in the different stages of granuloma development. The macrophages in zebrafish granulomas were shown to belong to distinct subtypes: epithelioid macrophages, foamy macrophages, and multinucleated giant cells. By defining the developmental stages of zebrafish granulomas and the spatial distribution of the different immune cells they contain, this work provides a reference for future studies of mycobacterial granulomas and their immune microenvironments.
Topics: Animals; Humans; Zebrafish; Mycobacterium; Tuberculosis; Mycobacterium Infections, Nontuberculous; Granuloma; Mycobacterium tuberculosis
PubMed: 37982587
DOI: 10.1093/jleuko/qiad145 -
Frontiers in Cellular and Infection... 2023() is a non-tuberculous (NTM) that can cause infectious diseases in aquatic animals and humans. Culture-based pathogen detection is the gold standard for diagnosing...
() is a non-tuberculous (NTM) that can cause infectious diseases in aquatic animals and humans. Culture-based pathogen detection is the gold standard for diagnosing NTM infection. However, this method is time-consuming and has low positivity rates for fastidious organisms. Oxford Nanopore MinION sequencing is an emerging third-generation sequencing technology that can sequence DNA or RNA directly in a culture-independent manner and offers rapid microbial identification. Further benefits include low cost, short turnaround time, long read lengths, and small equipment size. Nanopore sequencing plays a crucial role in assessing drug resistance, clinical identification of microbes, and monitoring infectious diseases. Some reports on (MTB) using nanopore sequencing have been published, however, there are few reports on NTM, such as . Here, we report the use of nanopore sequencing for the diagnosis of .
Topics: Animals; Humans; Nanopore Sequencing; Mycobacterium Infections, Nontuberculous; Mycobacterium marinum; Communicable Diseases; High-Throughput Nucleotide Sequencing
PubMed: 37965260
DOI: 10.3389/fcimb.2023.1238872 -
Archives of Microbiology Nov 2023Efferocytosis is characterized as the rapid and efficient process by which dying or dead cells are removed. This type of clearance is initiated via "find-me" signals,... (Review)
Review
Efferocytosis is characterized as the rapid and efficient process by which dying or dead cells are removed. This type of clearance is initiated via "find-me" signals, and then, carries on by "eat-me" and "don't-eat-me" ones. Efferocytosis has a critical role to play in tissue homeostasis and innate immunity. However, some evidence suggests it as a double-edged sword in microbial immunity. In other words, some pathogens have degraded efferocytosis by employing efferocytic mechanisms to bypass innate immune detection and promote infection, despite the function of this process for the control and clearance of pathogens. In this review, the efferocytosis mechanisms from the recognition of dying cells to phagocytic engulfment are initially presented, and then, its diverse roles in inflammation and immunity are highlighted. In this case, much focus is also laid on some bacterial, viral, and parasitic infections caused by Mycobacterium tuberculosis (M. tb), Mycobacterium marinum (M. marinum), Listeria monocytogenes (L. monocytogenes), Chlamydia pneumoniae (CP), Klebsiella pneumoniae (KP), Influenza A virus (IAV), human immunodeficiency virus (HIV), and Leishmania, respectively.
Topics: Humans; Macrophages; Phagocytosis; Immunity, Innate; Inflammation; Mycobacterium tuberculosis; Apoptosis
PubMed: 37925389
DOI: 10.1007/s00203-023-03704-8 -
Frontiers in Microbiology 2023Despite the great diversity of malonate semialdehyde decarboxylases (MSADs), one of five subgroups of the tautomerase superfamily (TSF) found throughout the biosphere,...
Phylogenetic distribution of malonate semialdehyde decarboxylase (MSAD) genes among strains within the genus : evidence of MSAD gene loss in the evolution of pathogenic mycobacteria.
Despite the great diversity of malonate semialdehyde decarboxylases (MSADs), one of five subgroups of the tautomerase superfamily (TSF) found throughout the biosphere, their distribution among strains within the genus remains unknown. In this study, we sought to investigate the phylogenetic distribution of MSAD genes of mycobacterial species via genome analysis of 192 different reference species or subspecies retrieved from NCBI databases. We found that in a total of 87 of 192 strains (45.3%), MSAD-1 and MSAD-2 were distributed in an exclusive manner among species except for 12 strains, including members, with both in their genome. Of note, strains better adapted to the host and of high virulence potential, such as the complex, , , , and subsp. , had no orthologs of MSAD in their genome, suggesting MSAD loss during species differentiation in pathogenic slow-growing . To investigate the MSAD distribution among strains of subspecies, the genome sequences of a total of 255 reference strains from the four subspecies of (43 of subspecies , 162 of subspecies , 49 of subspecies , and 1 of subspecies ) were further analyzed. We found that only 121 of 255 strains (47.4%) had MSADs in their genome, with none of the 49 subsp. strains having MSAD genes. Even in 13 of 121 strains with the MSAD-1 gene in their genome, deletion mutations in the 98th codon causing premature termination of MSAD were found, further highlighting the occurrence of MSAD pseudogenization during species or subspecies differentiation of In conclusion, our data indicated that there are two distinct types of MSADs, MSAD-1 and MSAD-2, among strains in the genus, but more than half of the strains, including pathogenic mycobacteria, and , have no orthologs in their genome, suggesting MSAD loss during host adaptation of pathogenic mycobacteria. In the future, the role of two distinct MSADs, MSAD-1 and MSAD-2, in mycobacterial pathogenesis or evolution should be investigated.
PubMed: 37901833
DOI: 10.3389/fmicb.2023.1275616 -
Microorganisms Oct 2023Hydroxamic acid (HA) derivatives display antibacterial and antifungal activities. HA with various numbers of carbon atoms (C, C, C, C, C and C), complexed with different...
Hydroxamic acid (HA) derivatives display antibacterial and antifungal activities. HA with various numbers of carbon atoms (C, C, C, C, C and C), complexed with different metal ions, including Fe(II/III), Ni(II), Cu(II) and Zn(II), were evaluated for their antimycobacterial activities and their anti-biofilm activities. Some derivatives showed antimycobacterial activities, especially in biofilm growth conditions. For example, 20-100 µM of HA10Fe2, HA10FeCl, HA10Fe3, HA10Ni2 or HA10Cu2 inhibited , BCG and biofilm development. HA10Fe2, HA12Fe2 and HA12FeCl could even attack pre-formed biofilms at higher concentrations (around 300 µM). The phthiocerol dimycocerosate (PDIM)-deficient H37Ra was more sensitive to the ion complexes of HA compared to other mycobacterial strains. Furthermore, HA10FeCl could increase the susceptibility of BCG to vancomycin. Proteomic profiles showed that the potential targets of HA10FeCl were mainly related to mycobacterial stress adaptation, involving cell wall lipid biosynthesis, drug resistance and tolerance and siderophore metabolism. This study provides new insights regarding the antimycobacterial activities of HA and their complexes, especially about their potential anti-biofilm activities.
PubMed: 37894269
DOI: 10.3390/microorganisms11102611 -
Frontiers in Immunology 2023In this work, we aimed at investigating cell and tissue responses of the apple snail , following the inoculation of the zoonotic pathogen . Different doses were tested...
In this work, we aimed at investigating cell and tissue responses of the apple snail , following the inoculation of the zoonotic pathogen . Different doses were tested (10, 20, 65, and 100 M CFU) and the mortality rate was negligible. The histopathogenesis was followed at 4, 9, and 28 days after inoculation. Overt histopathological lesions were consistently observed after the two largest doses only. In the lung, marked hemocyte aggregations, including intravascular nodule formation, were observed within the large blood veins that run along the floor and roof of this organ. Hemocyte aggregations were found occluding many of the radial sinuses supplying the respiratory lamina. Acid-fast bacilli were contained in the different hemocyte aggregations. In addition, hemocytes were observed infiltrating the storage tissue, which makes up most of the lung wall, and the connective tissue of the mantle edge. Additionally, signs of degradation in the storage tissue were observed in the lung wall on day 28. In the kidney, nodules were formed associated with the constitutive hemocyte islets and with the subpallial hemocoelic space, in whose hemocytes the acid-fast structures were found. Electron microscopy analysis revealed the presence of bacteria-containing phagosomes within hemocytes located in the surface zone of the islets. Additionally, electron-dense spheroidal structures, which are likely remnants of digested mycobacteria, were observed in close proximity to the hemocytes' nuclei. The size attained by the hemocyte nodules varied during the observation period, but there was no clear dependence on dose or time after inoculation. Nodules were also formed subpallially. Some of these nodules showed 2-3 layers with different cellular composition, suggesting they may also form through successive waves of circulating cells reaching them. Nodular cores, including those formed intravascularly in the lung, would exhibit signs of hemocyte dedifferentiation, possibly proliferation, and death. Hemocyte congestion was observed in the hemocoelic spaces surrounding the pallial ends of the renal crypts, and the renal crypts themselves showed de-epithelization, particularly on day 28. The diverse cellular responses of to inoculation and the high resilience of this snail to the pathogen make it a suitable species for studying mycobacterial infections and their effects on cellular and physiological processes.
Topics: Animals; Snails; Hemocytes; Microscopy, Electron; Phagosomes; Lung
PubMed: 37876924
DOI: 10.3389/fimmu.2023.1253099 -
BioRxiv : the Preprint Server For... Jan 2024( ), the pathogenic bacterium that causes tuberculosis, has evolved sophisticated defense mechanisms to counteract the cytotoxicity of reactive oxygen species (ROS)...
UNLABELLED
( ), the pathogenic bacterium that causes tuberculosis, has evolved sophisticated defense mechanisms to counteract the cytotoxicity of reactive oxygen species (ROS) generated within host macrophages during infection. The gene in and ( ) plays a crucial role in defense mechanisms against ROS generated during infection. We demonstrate that encodes an epoxide hydrolase and contributes to ROS detoxification. Deletion of in resulted in a mutant with increased sensitivity to oxidative stress, increased accumulation of aldehyde species, and decreased production of mycothiol and ergothioneine. This heightened vulnerability is attributed to the increased expression of , a universal stress sensor. The absence of also resulted in reduced intracellular levels of NAD , NADH, and ATP. Bacterial growth was impaired, even in the absence of external stressors, and the impairment was carbon-source-dependent. Initial MelH substrate specificity studies demonstrate a preference for epoxides with a single aromatic substituent. Taken together, these results highlight the role of in mycobacterial bioenergetic metabolism and provide new insights into the complex interplay between redox homeostasis and generation of reactive aldehyde species in mycobacteria.
IMPORTANCE
This study unveils the pivotal role played by the gene in and in combatting the detrimental impact of oxidative conditions during infection. This investigation revealed notable alterations in the level of cytokinin-associated aldehyde, -hydroxybenzaldehyde, as well as the redox buffer ergothioneine, upon deletion of . Moreover, changes in crucial cofactors responsible for electron transfer highlighted 's crucial function in maintaining a delicate equilibrium of redox and bioenergetic processes. MelH prefers epoxide small substrates with a phenyl substituted substrate. These findings collectively emphasize the potential of as an attractive target for the development of novel antitubercular therapies that sensitize mycobacteria to host stress, offering new avenues for combating tuberculosis.
PubMed: 37873194
DOI: 10.1101/2023.10.02.560593