Faculty Opinions recommendation of Antisense phosphorodiamidate morpholino oligomers targeted to an essential gene inhibit Burkholderia cepacia complex.

Author(s):  
Joseph McCune ◽  
Paul Baum

2020 ◽  
Author(s):  
Olga Mannweiler ◽  
Marta Pinto-Carbó ◽  
Martina Lardi ◽  
Kirsty Agnoli ◽  
Leo Eberl

AbstractThe Burkholderia cepacia complex (Bcc) is a group of 22 closely related opportunistic pathogens which produce a wide range of bioactive secondary metabolites with great biotechnological potential, for example in biocontrol and bioremediation.This study aimed to investigate methylation in the Bcc by SMRT sequencing, and to determine the impact of restriction-methylation (RM) systems on genome protection and stability and on phenotypic traits. We constructed and analysed a mutant lacking all RM components in the clinical isolate B. cenocepacia H111. We show that a previously identified essential gene of strain H111, gp51, encoding a methylase within a prophage region, is required for maintaining the bacteriophage in a lysogenic state. We speculate that epigenetic modification of a phage promoter provides a mechanism for a constant, low level of phage production within the bacterial population. We also found that, in addition to bacteriophage induction, methylation was important in biofilm formation, cell shape, motility, siderophore production and membrane vesicle production. Moreover, we found that DNA methylation had a massive effect on the maintenance of the smallest replicon present in this bacterium, which is essential for its virulence.In silico investigation revealed the presence of two core RM systems, present throughout the Bcc and beyond, suggesting that the acquisition of these RM systems occurred prior to the phylogenetic separation of the Bcc. We used SMRT sequencing of single mutants to experimentally assign the B. cenocepacia H111 methylases to their cognate motifs. Analysis of the distribution of methylation patterns suggested roles for m6A methylation in replication, since motifs recognised by the core Type III RM system were more abundant at the replication origins of the three H111 replicons, and in regions encoding functions related to cell motility and iron uptake.Author summaryWhile nucleotide sequence determines an organism’s proteins, methylation of the nucleotides themselves can confer additional properties. In bacteria, methyltransferases methylate specific motifs to allow discrimination of ‘self’ from ‘non-self’ DNA, e.g. from bacteriophages. Restriction enzymes detect ‘non-self’ methylation patterns and cut foreign DNA. Furthermore, methylation of promoter regions can influence gene expression and hence affect phenotype. In this study, we determined the methylated motifs of four strains from the Burkholderia cepacia complex of opportunistic pathogens. Three novel motifs were found, and two that were previously identified in a related species. We deleted the genes encoding the restriction and modification components in a representative strain from among the four sequenced. In this study, methylation is shown to affect various phenotypes, among which maintenance of the lysogenic state of a phage and segregational stability of the smallest megareplicon are most remarkable.



2012 ◽  
Vol 56 (12) ◽  
pp. 6147-6153 ◽  
Author(s):  
Susan E. Puckett ◽  
Kaleb A. Reese ◽  
Georgi M. Mitev ◽  
Valerie Mullen ◽  
Rudd C. Johnson ◽  
...  

ABSTRACTPeptide phosphorodiamidate morpholino oligomers (PPMOs) are synthetic DNA mimics that bind cRNA and inhibit bacterial gene expression. The PPMO (RFF)3RXB-AcpP (where R is arginine, F, phenylalanine, X is 6-aminohexanoic acid, B is β-alanine, and AcpP is acyl carrier protein) is complementary to 11 bases of the essential geneacpP(which encodes acyl carrier protein). The MIC of (RFF)3RXB-AcpP was 2.5 μM (14 μg/ml) inEscherichia coliW3110. The rate of spontaneous resistance ofE. colito (RFF)3RXB-AcpP was 4 × 10−7mutations/cell division. A spontaneous (RFF)3RXB-AcpP-resistant mutant (PR200.1) was isolated. The MIC of (RFF)3RXB-AcpP was 40 μM (224 μg/ml) for PR200.1. The MICs of standard antibiotics for PR200.1 and W3110 were identical. The sequence ofacpPwas identical in PR200.1 and W3110. PR200.1 was also resistant to other PPMOs conjugated to (RFF)3RXB or peptides with a similar composition or pattern of cationic and nonpolar residues. Genomic sequencing of PR200.1 identified a mutation insbmA, which encodes an active transport protein. In separate experiments, a (RFF)3RXB-AcpP-resistant isolate (RR3) was selected from a transposome library, and the insertion was mapped tosbmA. Genetic complementation of PR200.1 or RR3 withsbmArestored susceptibility to (RFF)3RXB-AcpP. Deletion ofsbmAcaused resistance to (RFF)3RXB-AcpP. We conclude that resistance to (RFF)3RXB-AcpP was linked to the peptide and not the phosphorodiamidate morpholino oligomer, dependent on the composition or repeating pattern of amino acids, and caused by mutations insbmA. The data further suggest that (RFF)3R-XB PPMOs may be transported across the plasma membrane by SbmA.



2020 ◽  
Vol 9 (1) ◽  
pp. 51
Author(s):  
Min Yi Wong ◽  
Yuan-Hsi Tseng ◽  
Tsung-Yu Huang ◽  
Bor-Shyh Lin ◽  
Chun-Wu Tung ◽  
...  

Burkholderia cepacia complex (BCC) is a group of closely related bacteria with widespread environmental distribution. BCC bacteria are opportunistic pathogens that cause nosocomial infections in patients, especially cystic fibrosis (CF). Multilocus sequence typing (MLST) is used nowadays to differentiate species within the BCC complex. This study collected 41 BCC isolates from vascular access infections (VAIs) and other clinical infections between 2014 and 2020. We preliminarily identified bacterial isolates using standard biochemical procedures and further conducted recA gene sequencing and MLST for species identification. We determined genetic diversity indices using bioinformatics software. We studied 14 isolates retrieved from patients with VAIs and observed that Burkholderia cepacia was the predominant bacterial species, and B. contaminans followed by B. cenocepacia were mainly retrieved from patients with other infections. According to MLST data, we identified that all B. contaminans isolates belonged to ST102, while a wide variety of sequence types (STs) were found in B. cenocepacia isolates. In summary, the high diversity and easy transmission of BCC increase BCC infections, which provides insights into their potential clinical effects in non-CF infections.



2013 ◽  
Vol 41 (11) ◽  
pp. 1038-1042 ◽  
Author(s):  
Maria Beatriz Souza Dias ◽  
Larissa G.T. Cavassin ◽  
Valeska Stempliuk ◽  
Luciene S. Xavier ◽  
Renata D. Lobo ◽  
...  


2013 ◽  
Vol 31 (10) ◽  
pp. 665-668 ◽  
Author(s):  
Laura Barrado ◽  
M. Teresa Martinez ◽  
Jennifer Villa ◽  
M. Ángeles Orellana ◽  
Esther Viedma ◽  
...  


2002 ◽  
Vol 70 (5) ◽  
pp. 2715-2720 ◽  
Author(s):  
Karen K. Chu ◽  
Donald J. Davidson ◽  
T. Keith Halsey ◽  
Jacqueline W. Chung ◽  
David P. Speert

ABSTRACT Cystic fibrosis patients infected with strains from different genomovars of the Burkholderia cepacia complex can experience diverse clinical outcomes. To identify genomovar-specific determinants that might be responsible for these differences, we developed a pulmonary model of infection in BALB/c mice. Mice were rendered leukopenic by administration of cyclophosphamide prior to intranasal challenge with 1.6 × 104 bacteria. Five of six genomovar II strains persisted at stable numbers in the lungs until day 16 with minimal toxicity, whereas zero of seven genomovar III strains persisted but resulted in variable toxicity. We have developed a chronic pulmonary model of B. cepacia infection which reveals differences among genomovars in terms of clinical infection outcome.



BioMetals ◽  
2007 ◽  
Vol 20 (3-4) ◽  
pp. 431-452 ◽  
Author(s):  
Mark S. Thomas


2017 ◽  
Vol 16 ◽  
pp. S98
Author(s):  
L.R. Avetisyan ◽  
M.Y. Chernukha ◽  
I.A. Shaginyan ◽  
E.A. Siyanova ◽  
D.G. Kulyastova ◽  
...  


2003 ◽  
Vol 18 (2) ◽  
Author(s):  
M.L. Garlaschi ◽  
L. Cariani ◽  
M. Busetti ◽  
E. Grasso ◽  
P. Grassi ◽  
...  


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