-
Scientific Reports May 2020Sortase enzymes are attractive antivirulence drug targets that attach virulence factors to the surface of Staphylococcus aureus and other medically significant bacterial...
Sortase enzymes are attractive antivirulence drug targets that attach virulence factors to the surface of Staphylococcus aureus and other medically significant bacterial pathogens. Prior efforts to discover a useful sortase inhibitor have relied upon an in vitro activity assay in which the enzyme is removed from its native site on the bacterial surface and truncated to improve solubility. To discover inhibitors that are effective in inactivating sortases in vivo, we developed and implemented a novel cell-based screen using Actinomyces oris, a key colonizer in the development of oral biofilms. A. oris is unique because it exhibits sortase-dependent growth in cell culture, providing a robust phenotype for high throughput screening (HTS). Three molecules representing two unique scaffolds were discovered by HTS and disrupt surface protein display in intact cells and inhibit enzyme activity in vitro. This represents the first HTS for sortase inhibitors that relies on the simple metric of cellular growth and suggests that A. oris may be a useful platform for discovery efforts targeting sortase.
Topics: Actinomyces; Aminoacyltransferases; Bacterial Proteins; Biofilms; Cells, Cultured; Enzyme Inhibitors; High-Throughput Screening Assays
PubMed: 32444661
DOI: 10.1038/s41598-020-65256-x -
Applied and Environmental Microbiology Sep 2018The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not...
The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not well understood. Recently, we isolated subsp. strain XH001 from the human oral cavity, and genomic analysis revealed the presence of an intact prophage named xhp1. Here, we demonstrated that xhp1 is a linear plasmid-like prophage, which is a newly identified phage of The prophage xhp1 genome is a 35-kb linear double-stranded DNA with 10-bp single-stranded, 3' cohesive ends. xhp1 exists extrachromosomally, with an estimated copy number of 5. Annotation of xhp1 revealed 54 open reading frames, while phylogenetic analysis suggests that it has limited similarity with other phages. xhp1 phage particles can be induced by mitomycin C and belong to the family, according to transmission electron microscopic examination. The released xhp1 particles can reinfect the xhp1-cured XH001 strain and result in tiny blurry plaques. Moreover, xhp1 promotes XH001 biofilm formation through spontaneous induction and the release of host extracellular DNA (eDNA). In conclusion, we identified a linear plasmid-like prophage of , which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity. The biology of phages as members of the human oral microbiome is understudied. Here, we report the characterization of xhp1, a novel linear plasmid-like prophage identified from a human oral isolate, subsp. strain XH001. xhp1 can be induced and reinfect xhp1-cured XH001. The spontaneous induction of xhp1 leads to the lysis of a subpopulation of bacterial hosts and the release of eDNA that promotes biofilm assembly, thus potentially contributing to the persistence of within the oral cavity.
Topics: Actinomyces; Biofilms; Genome, Bacterial; Genome, Viral; Humans; Lysogeny; Microscopy, Electron, Transmission; Mouth; Phylogeny; Plasmids; Prophages; Siphoviridae
PubMed: 29915115
DOI: 10.1128/AEM.01263-18 -
Monaldi Archives For Chest Disease =... Dec 2021Dear Editor, We read with interest the article by Balis et al. on pulmonary tuberculosis and actinomyces co-infection as a lung mass....
Dear Editor, We read with interest the article by Balis et al. on pulmonary tuberculosis and actinomyces co-infection as a lung mass....
Topics: Actinomyces; Actinomycosis; Coinfection; Humans; Lung; Mycobacterium
PubMed: 34874131
DOI: 10.4081/monaldi.2021.2102 -
TheScientificWorldJournal 2012Actinobaculum suis is an important agent related to urinary infection in swine females. Due to its fastidious growth characteristics, the isolation of this anaerobic...
Actinobaculum suis is an important agent related to urinary infection in swine females. Due to its fastidious growth characteristics, the isolation of this anaerobic bacterium is difficult, thus impairing the estimation of its prevalence. The purpose of this study was to develop and test a polymerase chain reaction (PCR) for the detection and identification of A. suis and then compare these results with traditional isolation methods. Bacterial isolation and PCR were performed on one hundred and ninety-two urine samples from sows and forty-five preputial swabs from boars. The results indicate that this PCR was specific for A. suis, presenting a detection limit between 1.0 × 10(1) CFU/mL and 1.0 × 10(2) CFU/mL. A. suis frequencies, as measured by PCR, were 8.9% (17/192) in sow urine samples and 82.2% (37/45) in preputial swabs. Assessed using conventional culturing techniques, none of the urine samples were positive for A. suis; however, A. suis was detected in 31.1% (14/45) of the swabs. This PCR technique was shown to be an efficient method for the detection of A. suis in urine and preputial swabs.
Topics: Actinomycetaceae; Actinomycetales Infections; Animals; DNA, Bacterial; Female; Male; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Reproducibility of Results; Sensitivity and Specificity; Sequence Analysis, DNA; Swine; Swine Diseases
PubMed: 23346017
DOI: 10.1100/2012/572732 -
MicrobiologyOpen Jan 2021To survive within complex environmental niches, including the human host, bacteria have evolved intricate interspecies communities driven by competition for limited...
To survive within complex environmental niches, including the human host, bacteria have evolved intricate interspecies communities driven by competition for limited nutrients, cooperation via complementary metabolic proficiencies, and establishment of homeostatic relationships with the host immune system. The study of such complex, interdependent relationships is often hampered by the challenges of culturing many bacterial strains in research settings and the limited set of tools available for studying the dynamic behavior of multiple bacterial species at the microscale. Here, we utilize a microfluidic-based co-culture system and time-lapse imaging to characterize dynamic interactions between Streptococcus species, Staphylococcus aureus, and Actinomyces species. Co-culture of Streptococcus cristatus or S. salivarius in nanoliter compartments with Actinomyces graevenitzii revealed localized exclusion of Streptococcus and Staphylococcus from media immediately surrounding A. graevenitzii microcolonies. This community structure did not occur with S. mitis or S. oralis strains or in co-cultures containing other Actinomycetaceae species such as S. odontolyticus or A. naeslundii. Moreover, fewer neutrophils were attracted to compartments containing both A. graevenitzii and Staphylococcus aureus than to an equal number of either species alone, suggesting a possible survival benefit together during immune responses.
Topics: Actinomyces; Antibiosis; Biofilms; Coculture Techniques; Host Microbial Interactions; Humans; Immunity, Innate; Microbiota; Microfluidics; Mouth; Neutrophils; Staphylococcus aureus; Streptococcus
PubMed: 33544453
DOI: 10.1002/mbo3.1137 -
Acta Crystallographica. Section D,... Nov 2023Cell-surface proteins known as adhesins enable bacteria to colonize particular environments, and in Gram-positive bacteria often contain autocatalytically formed...
Cell-surface proteins known as adhesins enable bacteria to colonize particular environments, and in Gram-positive bacteria often contain autocatalytically formed covalent intramolecular cross-links. While investigating the prevalence of such cross-links, a remarkable example was discovered in Mobiluncus mulieris, a pathogen associated with bacterial vaginosis. This organism encodes a putative adhesin of 7651 residues. Crystallography and mass spectrometry of two selected domains, and AlphaFold structure prediction of the remainder of the protein, were used to show that this adhesin belongs to the family of thioester, isopeptide and ester-bond-containing proteins (TIE proteins). It has an N-terminal domain homologous to thioester adhesion domains, followed by 51 immunoglobulin (Ig)-like domains containing ester- or isopeptide-bond cross-links. The energetic cost to the M. mulieris bacterium in retaining such a large adhesin as a single gene or protein construct suggests a critical role in pathogenicity and/or persistence.
Topics: Female; Humans; Mobiluncus; Adhesins, Bacterial; Esters
PubMed: 37860959
DOI: 10.1107/S2059798323007507 -
ELife Mar 2017The connection between gene loss and the functional adaptation of retained proteins is still poorly understood. We apply phylogenomics and metabolic modeling to detect...
The connection between gene loss and the functional adaptation of retained proteins is still poorly understood. We apply phylogenomics and metabolic modeling to detect bacterial species that are evolving by gene loss, with the finding that Actinomycetaceae genomes from human cavities are undergoing sizable reductions, including loss of L-histidine and L-tryptophan biosynthesis. We observe that the dual-substrate phosphoribosyl isomerase A or gene, at which these pathways converge, appears to coevolve with the occurrence of and genes. Characterization of a dozen PriA homologs shows that these enzymes adapt from bifunctionality in the largest genomes, to a monofunctional, yet not necessarily specialized, inefficient form in genomes undergoing reduction. These functional changes are accomplished via mutations, which result from relaxation of purifying selection, in residues structurally mapped after sequence and X-ray structural analyses. Our results show how gene loss can drive the evolution of substrate specificity from retained enzymes.
Topics: Actinomycetaceae; Adaptation, Biological; Aldose-Ketose Isomerases; Evolution, Molecular; Gene Deletion; Mutation; Substrate Specificity
PubMed: 28362260
DOI: 10.7554/eLife.22679 -
Journal of Clinical Microbiology Dec 1993
Comparative Study
Topics: Actinomyces; Actinomycetales; Fatty Acids; Humans; Species Specificity
PubMed: 8308138
DOI: 10.1128/jcm.31.12.3353-3354.1993 -
Marine Drugs Feb 2023Antarctic krill () of the family comprise one of the largest biomasses in the world and play a key role in the Antarctic marine ecosystem. However, the study of...
Antarctic krill () of the family comprise one of the largest biomasses in the world and play a key role in the Antarctic marine ecosystem. However, the study of -derived microbes and their secondary metabolites has been limited. Chemical investigation of the secondary metabolites of the actinomycetes sp. LX-1 (in the family of ), isolated from , combined with molecular networking, led to the identification of 16 compounds - (purple nodes in the molecular network) and the isolation of one new pyrroline, nocarpyrroline A (), along with 11 known compounds -. The structure of the new compound was elucidated by extensive spectroscopic investigation. Compound exhibited broad-spectrum antibacterial activities against , , , and antifungal activity against in a conventional broth dilution assay. The positive control was ciprofloxacin with the MIC values of <0.024 µM, 0.39 µM, 0.39 µM, 0.39 µM, and 0.20 µM, respectively. Compound and compounds , , and displayed antifungal activities against and , respectively, in modified agar diffusion test. Prochloraz was used as positive control and showed the inhibition zone radius of 17 mm and 15 mm against and , respectively. All the annotated compounds - by molecular networking were first discovered from the genus . Nocarpyrroline A () features an unprecedented 4,5-dihydro-pyrrole-2-carbonitrile substructure, and it is the first pyrroline isolated from the genus . This study further demonstrated the guiding significance of molecular networking in the research of microbial secondary metabolites.
Topics: Animals; Actinobacteria; Nocardiopsis; Euphausiacea; Actinomyces; Antifungal Agents; Ecosystem; Pyrroles; Antarctic Regions
PubMed: 36827168
DOI: 10.3390/md21020127 -
Molecular Medicine Reports Aug 2020Periodontitis affects oral tissues and induces systemic inflammation, which increases the risk of cardiovascular disease and metabolic syndrome. Subgingival plaque...
Periodontitis affects oral tissues and induces systemic inflammation, which increases the risk of cardiovascular disease and metabolic syndrome. Subgingival plaque accumulation is a trigger of periodontitis. Fusobacterium nucleatum (FN) contributes to subgingival biofilm complexity by intercalating with early and late bacterial colonizers on tooth surfaces. In addition, inflammatory responses to FN are associated with the progression of periodontitis. Nigella sativa Lin. seed, which is known as black cumin (BC), has been used as a herbal medicine to treat ailments such as asthma and infectious diseases. The current study examined the inhibitory effect of BC oil and its active constituents, thymol (TM) and thymoquinone (TQ), on FN‑associated biofilm and inflammation. FN‑containing biofilms were prepared by co‑cultivation with an early dental colonizer, Actinomyces naeslundii (AN). The stability and biomass of FN/AN dual species biofilms were significantly higher compared with FN alone. This effect was retained even with prefixed cells, indicating that FN/AN co‑aggregation is mediated by physicochemical interactions with cell surface molecules. FN/AN biofilm formation was significantly inhibited by 0.1% TM or TQ. Confocal laser scanning microscopy indicated that treatment of preformed FN/AN biofilm with 0.01% of BC, TM or TQ significantly reduced biofilm thickness, and TQ demonstrated a cleansing effect equivalent to that of isopropyl methylphenol. TQ dose‑dependently suppressed TNF‑α production from a human monocytic cell line, THP‑1 exposed to FN, yet showed no toxicity to THP‑1 cells. These results indicated that oral hygiene care using TQ could reduce FN‑associated biofilm and inflammation in gingival tissue.
Topics: Actinomyces; Benzoquinones; Biofilms; Fusobacterium nucleatum; Gingiva; Humans; Inflammation; Microscopy, Confocal; Periodontitis; Plant Oils; THP-1 Cells; Thymol; Tumor Necrosis Factor-alpha
PubMed: 32626941
DOI: 10.3892/mmr.2020.11136