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Emerging Infectious Diseases Mar 2021We report a case of melioidosis in China and offer a comparison of 5 commercial detection systems for Burkholderia pseudomallei. The organism was misidentified by the...
We report a case of melioidosis in China and offer a comparison of 5 commercial detection systems for Burkholderia pseudomallei. The organism was misidentified by the VITEK 2 Compact, Phoenix, VITEK mass spectrometry, and API 20NE systems but was eventually identified by the Bruker Biotyper system and 16S rRNA sequencing.
Topics: Burkholderia pseudomallei; China; Humans; Melioidosis; RNA, Ribosomal, 16S; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 33622484
DOI: 10.3201/eid2703.191769 -
Current Biology : CB Apr 2022Fungi and bacteria are ubiquitous constituents of all microbiomes, yet mechanisms of microbial persistence in polymicrobial communities remain obscure. Here, we examined...
Fungi and bacteria are ubiquitous constituents of all microbiomes, yet mechanisms of microbial persistence in polymicrobial communities remain obscure. Here, we examined the hypothesis that specialized fungal survival structures, chlamydospores, induced by bacterial lipopeptides serve as bacterial reservoirs. We find that symbiotic and pathogenic gram-negative bacteria from non-endosymbiotic taxa enter and propagate in chlamydospores. Internalized bacteria have higher fitness than planktonic bacteria when challenged with abiotic stress. Further, tri-cultures of Ralstonia solanacearum, Pseudomonas aeruginosa, and Aspergillus flavus reveal the unprecedented finding that chlamydospores are colonized by endofungal bacterial communities. Our work identifies a previously unknown ecological role of chlamydospores, provides an expanded view of microbial niches, and presents significant implications for the persistence of pathogenic and beneficial bacteria.
Topics: Bacteria; Fungi; Housing; Microbiota; Ralstonia solanacearum; Symbiosis
PubMed: 35235767
DOI: 10.1016/j.cub.2022.02.017 -
Microbiology Spectrum Feb 2022Chromids (secondary chromosomes) in bacterial genomes that are present in addition to the main chromosome appear to be evolutionarily conserved in some specific...
Chromids (secondary chromosomes) in bacterial genomes that are present in addition to the main chromosome appear to be evolutionarily conserved in some specific bacterial groups. In rare cases among these groups, a small number of strains from and were shown to possess a naturally fused single chromosome that was reported to have been generated through intragenomic homologous recombination between repeated sequences on the chromosome and chromid. Similar examples have never been reported in the family , a well-documented group that conserves chromids. Here, an in-depth genomic characterization was performed on a bacterium that was isolated from a soil bacterial consortium maintained on diesel fuel and mutagenic benzo[]pyrene. This organism, Cupriavidus necator strain KK10, was revealed to carry a single chromosome with unexpectedly large size (>6.6 Mb), and results of comparative genomics with the genome of C. necator N-1 indicated that the single chromosome of KK10 was generated through fusion of the prototypical chromosome and chromid at the rRNA operons. This fusion hypothetically occurred through homologous recombination with a crossover between repeated rRNA operons on the chromosome and chromid. Some metabolic functions that were likely expressed from genes on the prototypical chromid region were indicated to be retained. If this phenomenon-the bacterial chromosome-chromid fusion across the rRNA operons through homologous recombination-occurs universally in prokaryotes, the multiple rRNA operons in bacterial genomes may not only contribute to the robustness of ribosome function, but also provide more opportunities for genomic rearrangements through frequent recombination. A bacterial chromosome that was naturally fused with the secondary chromosome, or "chromid," and presented as an unexpectedly large single replicon was discovered in the genome of Cupriavidus necator strain KK10, a biotechnologically useful member of the family . Although is a well-documented group that conserves chromids in their genomes, this chromosomal fusion event has not been previously reported for this family. This fusion has hypothetically occurred through intragenomic homologous recombination between repeated rRNA operons and, if so, provides novel insight into the potential of multiple rRNA operons in bacterial genomes to lead to chromosome-chromid fusion. The harsh conditions under which strain KK10 was maintained-a genotoxic hydrocarbon-enriched milieu-may have provided this genotype with a niche in which to survive.
Topics: Burkholderiaceae; Chromosomes, Bacterial; Genome, Bacterial; Genomics; RNA, Bacterial; Recombination, Genetic; Replicon; rRNA Operon
PubMed: 34985328
DOI: 10.1128/spectrum.02225-21 -
The ISME Journal Jul 2020Rhizopus microsporus is an early-diverging fungal species with importance in ecology, agriculture, food production, and public health. Pathogenic strains of R....
Rhizopus microsporus is an early-diverging fungal species with importance in ecology, agriculture, food production, and public health. Pathogenic strains of R. microsporus harbor an intracellular bacterial symbiont, Mycetohabitans (formerly named Burkholderia). This vertically transmitted bacterial symbiont is responsible for the production of toxins crucial to the pathogenicity of Rhizopus and remarkably also for fungal reproduction. Here we show that R. microsporus can live not only in symbiosis with bacteria but also with two viral members of the genus Narnavirus. Our experiments revealed that both viruses replicated similarly in the growth conditions we tested. Viral copies were affected by the developmental stage of the fungus, the substrate, and the presence or absence of Mycetohabitans. Absolute quantification of narnaviruses in isolated asexual sporangiospores and sexual zygospores indicates their vertical transmission. By curing R. microsporus of its viral and bacterial symbionts and reinfecting bacteria to reestablish symbiosis, we demonstrate that these viruses affect fungal biology. Narnaviruses decrease asexual reproduction, but together with Mycetohabitans, are required for sexual reproductive success. This fungal-bacterial-viral system represents an outstanding model to investigate three-way microbial symbioses and their evolution.
Topics: Burkholderia; Rhizopus; Spores, Fungal; Symbiosis
PubMed: 32269378
DOI: 10.1038/s41396-020-0638-y -
The American Journal of Tropical... Jun 2023
Topics: Humans; Burkholderia pseudomallei; Melioidosis
PubMed: 37160279
DOI: 10.4269/ajtmh.23-0223 -
Applied and Environmental Microbiology Feb 2022It has been demonstrated that quorum sensing (QS) is widely employed by bacterial cells to coordinately regulate various group behaviors. Diffusible signal factor... (Review)
Review
It has been demonstrated that quorum sensing (QS) is widely employed by bacterial cells to coordinately regulate various group behaviors. Diffusible signal factor (DSF)-type signals have emerged as a growing family of conserved cell-cell communication signals. In addition to the DSF signal initially identified in Xanthomonas campestris pv. campestris, iffusible ignal actor (BDSF) (-2-dodecenoic acid) has been recognized as a conserved DSF-type signal with specific characteristics in both signal perception and transduction from DSF signals. Here, we review the history and current progress of the research on this type of signal, especially focusing on its biosynthesis, signaling pathways, and biological functions. We also discuss and explore the huge potential of targeting this kind of QS system as a new therapeutic strategy to control bacterial infections and diseases.
Topics: Bacterial Proteins; Burkholderia; Burkholderia cenocepacia; Fatty Acids, Monounsaturated; Gene Expression Regulation, Bacterial; Quorum Sensing; Suppressor Factors, Immunologic
PubMed: 34985987
DOI: 10.1128/aem.02342-21 -
The International Journal of... Oct 2023Melioidosis is a potentially life-threatening infection caused by the Gram-negative bacillus . Mediastinal melioidosis has a range of clinical presentations, making it... (Review)
Review
Melioidosis is a potentially life-threatening infection caused by the Gram-negative bacillus . Mediastinal melioidosis has a range of clinical presentations, making it difficult to diagnose: we therefore reviewed the evidence on the clinical characteristics, radiological features and invasive diagnostic modalities or interventions. An electronic search was conducted on three databases (PubMed, SCOPUS, Google Scholar) from November to December 2022. The initial search yielded 120 results, of which 34 studies met the inclusion criteria, but only 31 full-texts were retrievable. Among these, 4 were cohort studies, 26 case reports or series and 1 a conference abstract. The four main themes covered were mediastinal melioidosis as a diagnostic dilemma, unexpected complications, invasive interventions or an accompanying thoracic feature. Radiological manifestations included matting, necrosis and abscess-like collection. Severe presentations of mediastinal melioidosis included superior vena cava obstruction, sinus tract formation and pericardial tamponade. Transbronchial needle aspiration was the most common invasive diagnostic modality. Further research is needed to understand the relationship between the thoracic features of melioidosis on patient prognosis, its relationship to melioidosis transmission and potential preventive measures.
Topics: Humans; Burkholderia pseudomallei; Melioidosis; Radiography; Vena Cava, Superior
PubMed: 37749834
DOI: 10.5588/ijtld.23.0079 -
Microbiological Research Sep 2020Ralstonia solanacearum is a scientifically/economically important plant pathogenic bacterium. The plant disease caused by R. solanacearum causes huge economic losses,...
Ralstonia solanacearum is a scientifically/economically important plant pathogenic bacterium. The plant disease caused by R. solanacearum causes huge economic losses, and efficient control measures for the disease remain limited. To gain a better system-level understanding of R. solanacearum, we generated a near-saturated transposon insertion library of R. solanacearum GMI1000 with approximately 240,000 individual insertion mutants. Transposon sequencing (Tn-seq) allowed the mapping of 70.44%-80.96% of all potential insertion sites of the mariner C9 transposase in the genome of R. solanacearum and the identification of 465 genes essential for the growth of R. solanacearum in rich medium. Functional and comparative analyses of essential genes revealed that many basic physiological and biochemical processes such as transcription differ between R. solanacearum and other bacteria. A comparative analysis of essential genes also suggested that 34 genes might be essential only for Ralstonia group bacteria, whereas another 16 essential genes are unique to Ralstonia, providing high-priority candidate targets for developing R. solanacearum-specific drugs.
Topics: Bacterial Proteins; Conjugation, Genetic; DNA-Binding Proteins; Gene Library; Genes, Essential; Genome, Bacterial; Mutagenesis, Insertional; Plant Diseases; Plants; Ralstonia solanacearum; Transposases
PubMed: 32502949
DOI: 10.1016/j.micres.2020.126500 -
Microbial Physiology 2021An astonishing variety of functions has been attributed to polyphosphate (polyP) in prokaryotes. Besides being a reservoir of phosphorus, functions in exopolysaccharide... (Review)
Review
An astonishing variety of functions has been attributed to polyphosphate (polyP) in prokaryotes. Besides being a reservoir of phosphorus, functions in exopolysaccharide formation, motility, virulence and in surviving various forms of stresses such as exposure to heat, extreme pH, oxidative agents, high osmolarity, heavy metals and others have been ascribed to polyP. In this contribution, we will provide a historical overview on polyP, will then describe the key proteins of polyP synthesis, the polyP kinases, before we will critically assess of the underlying data on the multiple functions of polyP and provide evidence that - with the exception of a P-storage-function - most other functions of polyP are not relevant for survival of Ralstonia eutropha, a biotechnologically important beta-proteobacterial species.
Topics: Cupriavidus necator; Polyphosphates
PubMed: 34015783
DOI: 10.1159/000515741 -
PloS One 2022The genus Ardisia (Myrsinoideae, Primulaceae) has 16 subgenera and over 700 accepted names, mainly distributed in tropical Asia and America. The circumscription of...
The genus Ardisia (Myrsinoideae, Primulaceae) has 16 subgenera and over 700 accepted names, mainly distributed in tropical Asia and America. The circumscription of Ardisia is not well-defined and sometimes confounded with the separation of some small genera. A taxonomic revision focusing on Ardisia and allies is necessary. In the Ardisia subgenus Crispardisia, symbiotic association with leaf-nodule bacteria is a unique character within the genus. The endosymbionts are vertically transmitted, highly specific and highly dependent on the hosts, suggesting strict cospeciation may have occurred in the evolutionary history. In the present study, we aimed to establish a phylogenetic framework for further taxonomic revision. We also aimed to test the cospeciation hypothesis of the leaf-nodulate Ardisia and their endosymbiotic bacteria. Nuclear ITS and two chloroplast intergenic spaces were used to reconstruct the phylogeny of Asian Ardisia and relatives in Myrsinoideae, Primulaceae. The 16S-23S rRNA were used to reconstruct the bacterial symbionts' phylogeny. To understand the evolutionary association of the Ardisia and symbionts, topology tests and cophylogenetic analyses were conducted. The molecular phylogeny suggested Ardisia is not monophyletic, unless Sardiria, Hymenandra, Badula and Oncostemum are included. The results suggest the generic limit within Myrsinoideae (Primulaceae) needs to be further revised. The subgenera Crispardisia, Pimelandra, and Stylardisia were supported as monophyly, while the subgenus Bladhia was separated into two distant clades. We proposed to divide the subgenus Bladhia into subgenus Bladhia s.str. and subgenus Odontophylla. Both of the cophylogenetic analyses and topology tests rejected strict cospeciation hypothesis between Ardisia hosts and symbiotic Burkholderia. Cophylogenetic analyses showed general phylogenetic concordance of Ardisia and Burkholderia, and cospeciation events, host-switching events and loss events were all inferred.
Topics: Burkholderia
PubMed: 35045070
DOI: 10.1371/journal.pone.0261188