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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
791

Whole genome sequencing reveals mycobacterial microevolution among concurrent isolates from sputum and blood in HIV infected TB patients

Ssengooba, W., de Jong, B.C., Joloba, M.L., Cobelens, F.G., Meehan, Conor J. 05 November 2019 (has links)
Yes / Background In the context of advanced immunosuppression, M. tuberculosis is known to cause detectable mycobacteremia. However, little is known about the intra-patient mycobacterial microevolution and the direction of seeding between the sputum and blood compartments. Methods From a diagnostic study of HIV-infected TB patients, 51 pairs of concurrent blood and sputum M. tuberculosis isolates from the same patient were available. In a previous analysis, we identified a subset with genotypic concordance, based on spoligotyping and 24 locus MIRU-VNTR. These paired isolates with identical genotypes were analyzed by whole genome sequencing and phylogenetic analysis. Results Of the 25 concordant pairs (49 % of the 51 paired isolates), 15 (60 %) remained viable for extraction of high quality DNA for whole genome sequencing. Two patient pairs were excluded due to poor quality sequence reads. The median CD4 cell count was 32 (IQR; 16–101)/mm3 and ten (77 %) patients were on ART. No drug resistance mutations were identified in any of the sequences analyzed. Three (23.1 %) of 13 patients had SNPs separating paired isolates from blood and sputum compartments, indicating evidence of microevolution. Using a phylogenetic approach to identify the ancestral compartment, in two (15 %) patients the blood isolate was ancestral to the sputum isolate, in one (8 %) it was the opposite, and ten (77 %) of the pairs were identical. Conclusions Among HIV-infected patients with poor cellular immunity, infection with multiple strains of M. tuberculosis was found in half of the patients. In those patients with identical strains, whole genome sequencing indicated that M. tuberculosis intra-patient microevolution does occur in a few patients, yet did not reveal a consistent direction of spread between sputum and blood. This suggests that these compartments are highly connected and potentially seed each other repeatedly.
792

Comparative genomics of Mycobacterium africanum Lineage 5 and Lineage 6 from Ghana suggests distinct ecological niches

Otchere, I.D., Coscollá, M., Sánchez-Busó, L., Asante-Poku, A., Brites, D., Loiseau, C., Meehan, Conor J., Osei-Wusu, S., Forson, A., Laryea, C., Yahayah, A.I., Baddoo, A., Ansa, G.A., Aboagye, S.Y., Asare, P., Borrell, S., Gehre, F., Beckert, P., Kohl, T.A., N'dira, S., Beisel, C., Antonio, M., Niemann, S., de Jong, B.C., Parkhill, J., Harris, S.R., Gagneux, S., Yeboah-Manu, D. 2018 July 1926 (has links)
Yes / Mycobacterium africanum (Maf) causes a substantial proportion of human tuberculosis in some countries of West Africa, but little is known on this pathogen. We compared the genomes of 253 Maf clinical isolates from Ghana, including N = 175 Lineage 5 (L5) and N = 78 Lineage 6 (L6). We found that the genomic diversity of L6 was higher than in L5 despite the smaller sample size. Regulatory proteins appeared to evolve neutrally in L5 but under purifying selection in L6. Even though over 90% of the human T cell epitopes were conserved in both lineages, L6 showed a higher ratio of non-synonymous to synonymous single nucleotide variation in these epitopes overall compared to L5. Of the 10% human T cell epitopes that were variable, most carried mutations that were lineage-specific. Our findings indicate that Maf L5 and L6 differ in some of their population genomic characteristics, possibly reflecting different selection pressures linked to distinct ecological niches. / Supported by the Wellcome Trust Intermediate Fellowship awarded to DYM (Grant Number 097134/Z/11/Z) and by the Swiss National Science Foundation (grants 310030_166687, IZRJZ3_164171 and IZLSZ3_170834), the European Research Council (309540-EVODRTB) and SystemsX.ch.
793

Whole genome sequence of Mycobacterium kansasii isolates of the genotype 1 from Brazilian patients with pulmonary disease demonstrates considerable heterogeneity

Machado, E., Vasconcellos, S.E.G., Cerdeira, C., Gomes, L.L., Junqueira, R., de Carvalho, L.D., Ramos, J.P., Redner, P., Campos, C.E.D., de Souza Caldas, P.C., Gomes, A.P.C.S., Goldenberg, T., Montes, F.F., de Queiroz Mello, F.C., de Oliveira Mussi, V., Lasunskaia, E., van Soolingen, D., de Miranda, A.B., Rigouts, L., de Jong, B.C., Meehan, Conor J., Catanho, M., Suffys, P.N. 25 June 2018 (has links)
Yes / Mycobacterium kansasii is an opportunistic pathogen and one of the most commonly encountered species in individuals with lung disease. We here report the complete genome sequence of 12 clinical isolates of M. kansasii from patients with pulmonary disease in Brazil. / CNPq (scholarships 207422/2014-1, 500769/2014-1, 311554/2013-0; grants 407624/2012-0, 459100/2014-9).
794

Evaluation of Central Florida plants as a source of biologically active compounds against the thrombolytic protease thrombin, and the pathogenic organism mycobacterium tuberculosis : structural characterization of b-amyryl hexadecanoate from parthenocissus quinquefolia an inhibitor of thrombin

Chistokhodova, Natalya 01 April 2001 (has links)
No description available.
795

Lipoproteins of Mycobacterium tuberculosis: an abundant and functionally diverse class of cell envelope components

Sutcliffe, I.C., Harrington, Dean J. 2004 June 1918 (has links)
No / Mycobacterium tuberculosis remains the predominant bacterial scourge of mankind. Understanding of its biology and pathogenicity has been greatly advanced by the determination of whole genome sequences for this organism. Bacterial lipoproteins are a functionally diverse class of membrane-anchored proteins. The signal peptides of these proteins direct their export and post-translational lipid modification. These signal peptides are amenable to bioinformatic analysis, allowing the lipoproteins encoded in whole genomes to be catalogued. This review applies bioinformatic methods to the identification and functional characterisation of the lipoproteins encoded in the M. tuberculosis genomes. Ninety nine putative lipoproteins were identified and so this family of proteins represents ca. 2.5% of the M. tuberculosis predicted proteome. Thus, lipoproteins represent an important class of cell envelope proteins that may contribute to the virulence of this major pathogen.
796

The new phylogeny of the genus Mycobacterium: The old and the news

Tortoli, E., Fedrizzi, T., Meehan, Conor J., Trovato, A., Grottola, A., Giacobazzi, E., Fregni Serpini, G., Tagliazucchi, S., Fabio, A., Bettua, C., Bertorelli, R., Frascaro, F., De Sanctis, V., Pecorari, M., Jousson, O., Segata, N., Cirillo, D.M. 24 September 2019 (has links)
No / Background: Phylogenetic studies of bacteria have been based so far either on a single gene (usually the 16SrRNA) or on concatenated housekeeping genes. For what concerns the genus Mycobacterium these approaches support the separation of rapidly and slowly growing species and the clustering of most species in well-defined phylogenetic groups. The advent of high-throughput shotgun sequencing leads us to revise conventional tax-onomy of mycobacteria on the light of genomic data. For this purpose we investigated 88 newly sequenced species in addition to 60 retrieved from GenBank and used the Average Nucleotide Identity pairwise scores to reconstruct phylogenetic relationships within this genus.Results:Our analysis confirmed the separation of slow and rapid growers and the intermediate position occupied by the M. terrae complex. Among the rapid growers, the species of the M. chelonae-abscessus complex belonged to the most ancestral cluster. Other major clades of rapid growers included the species related to M. fortuitum and M. smegmatis and a large grouping containing mostly environmental species rarely isolated from humans. The members of the M. terrae complex appeared as the most ancestral slow growers. Among slow growers two deep branches led to the clusters of species related to M. celatum and M. xenopi and to a large group harboring most of the species more frequently responsible of disease in humans, including the major pathogenic mycobacteria (M.tuberculosis,M. leprae,M. ulcerans). The species previously grouped in the M. simiae complex were allocated in a number of sub-clades; of them, only the one including the species M. simiae identified the real members of this complex. The other clades included also species previously not considered related to M. simiae. The ANI analysis,in most cases supported by Genome to Genome Distance and by Genomic Signature-Delta Difference, showed that a number of species with standing in literature were indeed synonymous.Conclusions:Genomic data revealed to be much more informative in comparison with phenotype. We believe that the genomic revolution enabled by high-throughput shotgun sequencing should now be considered in order to revise the conservative approaches still informing taxonomic sciences.
797

Ancient Mycobacterium leprae genomes from the mediaeval sites of Chichester and Raunds in England

Kerudin, A., Müller, R., Buckberry, Jo, Knüsel, C.J., Brown, T.A. 28 November 2019 (has links)
Yes / We examined six skeletons from mediaeval contexts from two sites in England for the presence of Mycobacterium leprae DNA, each of the skeletons displaying osteological indicators of leprosy. Polymerase chain reactions directed at the species-specific RLEP multicopy sequence produced positive results with three skeletons, these being among those with the clearest osteological signs of leprosy. Following in-solution hybridization capture, sufficient sequence reads were obtained to cover >70% of the M. leprae genomes from these three skeletons, with a mean read depth of 4–10×. Two skeletons from a mediaeval hospital in Chichester, UK, dating to the 14th–17th centuries AD, contained M. leprae strains of subtype 3I, which has previously been reported in mediaeval England. The third skeleton, from a churchyard cemetery at Raunds Furnells, UK, dating to the 10th to mid-12th centuries AD, carried subtype 3K, which has been recorded at 7th–13th century AD sites in Turkey, Hungary and Denmark, but not previously in Britain. We suggest that travellers to the Holy Land might have been responsible for the transmission of subtype 3K from southeast Europe to Britain. / Funded by a studentship awarded by Majlis Amanah Rakyat (MARA) to A.K. and by the University of Bradford and the University of Manchester.
798

Capacity building for whole genome sequencing of Mycobacterium tuberculosis and bioinformatics in high TB burden countries.

Rivière, E., Heupink, T.H., Ismail, N., Dippenaar, A., Clarke, C., Abebe, G., Heusden van, P., Warren, R., Meehan, Conor J., Van Rie, A. 18 June 2021 (has links)
Yes / Whole genome sequencing (WGS) is increasingly used for Mycobacterium tuberculosis (Mtb) research. Countries with the highest tuberculosis (TB) burden face important challenges to integrate WGS into surveillance and research. We assessed the global status of Mtb WGS and developed a 3-week training course coupled with long-term mentoring and WGS infrastructure building. Training focused on genome sequencing, bioinformatics and development of a locally relevant WGS research project. The aim of the long-term mentoring was to support trainees in project implementation and funding acquisition. The focus of WGS infrastructure building was on the DNA extraction process and bioinformatics. Compared to their TB burden, Asia and Africa are grossly underrepresented in Mtb WGS research. Challenges faced resulted in adaptations to the training, mentoring and infrastructure building. Out-of-date laptop hardware and operating systems were overcome by using online tools and a Galaxy WGS analysis pipeline. A case studies approach created a safe atmosphere for students to formulate and defend opinions. Because quality DNA extraction is paramount for WGS, a biosafety level 3 and general laboratory skill training session were added, use of commercial DNA extraction kits was introduced and a 2-week training in a highly equipped laboratory was combined with a 1-week training in the local setting. By developing and sharing the components of and experiences with a sequencing and bioinformatics training program, we hope to stimulate capacity building programs for Mtb WGS and empower high-burden countries to play an important role in WGS-based TB surveillance and research. / Vlaamse Interuniversitaire Raad-secretariaat voor universitaire ontwikkelingssamenwerking (ET2018JOI008A10); the Research Foundation Flanders under FWO Odysseus (grant G0F8316N); the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation of South Africa (64751); the South African Medical Research Council.
799

A sister lineage of the Mycobacterium tuberculosis complex discovered in the African Great Lakes region

Ngabonziza, J.C.S., Loiseau, C., Marceau, M., Jouet, A., Menardo, F., Tzfadia, O., Antoine, R., Niyigena, E.B., Mulders, W., Fissette, K., Diels, M., Gaudin, C., Duthoy, S., Ssengooba, W., André, E., Kaswa, M.K., Habimana, Y.M., Brites, D., Affolabi, D., Mazarati, J.B., de Jong, B.C., Rigouts, L., Gagneux, S., Meehan, Conor J., Supply, P. 18 June 2021 (has links)
Yes / The human- and animal-adapted lineages of the Mycobacterium tuberculosis complex (MTBC) are thought to have expanded from a common progenitor in Africa. However, the molecular events that accompanied this emergence remain largely unknown. Here, we describe two MTBC strains isolated from patients with multidrug resistant tuberculosis, representing an as-yet-unknown lineage, named Lineage 8 (L8), seemingly restricted to the African Great Lakes region. Using genome-based phylogenetic reconstruction, we show that L8 is a sister clade to the known MTBC lineages. Comparison with other complete mycobacterial genomes indicate that the divergence of L8 preceded the loss of the cobF genome region - involved in the cobalamin/vitamin B12 synthesis - and gene interruptions in a subsequent common ancestor shared by all other known MTBC lineages. This discovery further supports an East African origin for the MTBC and provides additional molecular clues on the ancestral genome reduction associated with adaptation to a pathogenic lifestyle. / This work was supported by EDCTP2 grant DRIA2014-326—DIAMA of the European Union, the Belgian General Directorate for Development Cooperation (PhD fellowship to J.C.S.N.), Grant ANR-16-CE35-0009 from Agence Nationale de la Recherche, the Swiss National Science Foundation (Grants 310030_188888, IZRJZ3_164171, IZLSZ3_170834 and CRSII5_177163), and the European Research Council (309540-EVODRTB). The views and opinions of authors expressed herein do not necessarily state or reflect those of EDCTP. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
800

Characterization of Genomic Variants Associated with Resistance to Bedaquiline and Delamanid in Naive Mycobacterium tuberculosis Clinical Strains

Battaglia, S., Spitaleri, A., Cabibbe, A.M., Meehan, Conor J., Utpatel, C., Ismail, N., Tahseen, S., Skrahina, A., Alikhanova, N., Mostofa Kamal, S.M., Barbova, A., Niemann, S., Groenheit, R., Dean, A.S., Zignol, M., Rigouts, L., Cirillo, D.M. 18 June 2021 (has links)
No / The role of mutations in genes associated with phenotypic resistance to bedaquiline (BDQ) and delamanid (DLM) in Mycobacterium tuberculosis complex (MTBc) strains is poorly characterized. A clear understanding of the genetic variants' role is crucial to guide the development of molecular-based drug susceptibility testing (DST). In this work, we analyzed all mutations in candidate genomic regions associated with BDQ- and DLM-resistant phenotypes using a whole-genome sequencing (WGS) data set from a collection of 4,795 MTBc clinical isolates from six countries with a high burden of tuberculosis (TB). From WGS analysis, we identified 61 and 163 unique mutations in genomic regions potentially involved in BDQ- and DLM-resistant phenotypes, respectively. Importantly, all strains were isolated from patients who likely have never been exposed to these medicines. To characterize the role of mutations, we calculated the free energy variation upon mutations in the available protein structures of Ddn (DLM), Fgd1 (DLM), and Rv0678 (BDQ) and performed MIC assays on a subset of MTBc strains carrying mutations to assess their phenotypic effect. The combination of structural and phenotypic data allowed for cataloguing the mutations clearly associated with resistance to BDQ (n = 4) and DLM (n = 35), only two of which were previously described, as well as about a hundred genetic variants without any correlation with resistance. Significantly, these results show that both BDQ and DLM resistance-related mutations are diverse and distributed across the entire region of each gene target, which is of critical importance for the development of comprehensive molecular diagnostic tools.

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