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Nature Communications Aug 2019Phosphonates are rare and unusually bioactive natural products. However, most bacterial phosphonate biosynthetic capacity is dedicated to tailoring cell surfaces with...
Phosphonates are rare and unusually bioactive natural products. However, most bacterial phosphonate biosynthetic capacity is dedicated to tailoring cell surfaces with molecules like 2-aminoethylphosphonate (AEP). Although phosphoenolpyruvate mutase (Ppm)-catalyzed installation of C-P bonds is known, subsequent phosphonyl tailoring (Pnt) pathway steps remain enigmatic. Here we identify nucleotidyltransferases in over two-thirds of phosphonate biosynthetic gene clusters, including direct fusions to ~60% of Ppm enzymes. We characterize two putative phosphonyl tailoring cytidylyltransferases (PntCs) that prefer AEP over phosphocholine (P-Cho) - a similar substrate used by the related enzyme LicC, which is a virulence factor in Streptococcus pneumoniae. PntC structural analyses reveal steric discrimination against phosphocholine. These findings highlight nucleotidyl activation as a predominant chemical logic in phosphonate biosynthesis and set the stage for probing diverse phosphonyl tailoring pathways.
Topics: Actinobacteria; Aminoethylphosphonic Acid; Bacteria; Bacterial Proteins; Biosynthetic Pathways; Cell Wall; Crystallization; Crystallography, X-Ray; Escherichia coli; N-Acylneuraminate Cytidylyltransferase; Nucleotidyltransferases; Organophosphonates; Phospholipids; Phosphorylcholine; Phosphotransferases (Phosphomutases); Polysaccharides; Substrate Specificity
PubMed: 31420548
DOI: 10.1038/s41467-019-11627-6 -
Microbiology (Reading, England) Mar 2015This study monitored the dynamics and diversity of the human faecal 'Atopobium cluster' over a 3-month period using a polyphasic approach. Fresh faecal samples were...
This study monitored the dynamics and diversity of the human faecal 'Atopobium cluster' over a 3-month period using a polyphasic approach. Fresh faecal samples were collected fortnightly from 13 healthy donors (six males and seven females) aged between 26 and 61 years. FISH was used to enumerate total (EUB338mix) and 'Atopobium cluster' (ATO291) bacteria, with counts ranging between 1.12×10(11) and 9.95×10(11), and 1.03×10(9) and 1.16×10(11) cells (g dry weight faeces)(-1), respectively. The 'Atopobium cluster' population represented 0.2-22 % of the total bacteria, with proportions donor-dependent. Denaturing gradient gel electrophoresis (DGGE) using 'Atopobium cluster'-specific primers demonstrated faecal populations of these bacteria were relatively stable, with bands identified as Collinsella aerofaciens, Collinsella intestinalis/Collinsella stercoris, Collinsella tanakaei, Coriobacteriaceae sp. PEAV3-3, Eggerthella lenta, Gordonibacter pamelaeae, Olsenella profusa, Olsenella uli and Paraeggerthella hongkongensis in the DGGE profiles of individuals. Colony PCR was used to identify 'Atopobium cluster' bacteria isolated from faeces (n = 224 isolates). 16S rRNA gene sequence analysis of isolates demonstrated Collinsella aerofaciens represented the predominant (88 % of isolates) member of the 'Atopobium cluster' found in human faeces, being found in nine individuals. Eggerthella lenta was identified in three individuals (3.6 % of isolates). Isolates of Collinsella tanakaei, an 'Enorma' sp. and representatives of novel species belonging to the 'Atopobium cluster' were also identified in the study. Phenotypic characterization of the isolates demonstrated their highly saccharolytic nature and heterogeneous phenotypic profiles, and 97 % of the isolates displayed lipase activity.
Topics: Actinobacteria; Adult; Bacteria; Biodiversity; DNA, Bacterial; DNA, Ribosomal; Feces; Female; Humans; Male; Microbiota; Middle Aged; Molecular Sequence Data; Phenotype; Phylogeny; RNA, Ribosomal, 16S
PubMed: 25533445
DOI: 10.1099/mic.0.000016 -
The Journal of Contemporary Dental... Jan 2017Apical periodontitis usually results from bacterial accumulation and contamination occurring in the root-canal system, and extending beyond the apical foramen to involve...
INTRODUCTION
Apical periodontitis usually results from bacterial accumulation and contamination occurring in the root-canal system, and extending beyond the apical foramen to involve the periapical tissues. Literature has a paucity of the studies that stress on the division and analysis of the pulp canal segments. The reason for this disparity might be the technique used for collecting the samples from the pulp canals. Hence, we carried out the present study to evaluate the microbial flora in the apical part of the roots with necrotic pulp canals.
MATERIALS AND METHODS
The present study included the assessment of 40 freshly extracted teeth that had necrotized pulpal tissue along with the presence of periapical periodontal lesions. Removal of the soft tissue lesions attached to the root portion of the teeth along with apical periodontal lesions was done with the help of scalpel blade, after rinsing them with a sterile solution of saline. Thorough cleaning of the root surfaces was done with hydrogen peroxide followed by rapid disinfection with the help of sodium hypochlorite at varying concentrations. Sectioning of the root portion of all the specimens with the help of a disk was done perpendicular to the long axis of the teeth at a distance of roughly 5 to 6 mm from the teeth's apicalmost point. Cryotubes were used for transferring the specimens of apical portions containing 1 mL of buffer and were subjected to immediate frozen processing at a temperature of -20°C. A 10 K-type file was used for the initial collection of the samples followed by subsequent incubation of the files and paper pints in the incubation cabinet. Subsequent deoxyribonucleic acid (DNA) extraction from the samples was done following the procedure described by Siqueira et al. Paster et al's modification of the reverse-capture checkerboard assay was used in the present study. Semiquantitative data were used for overcoming the difficulties arising due to obtaining the counts of the polymerase chain reaction (PCR)-based analysis of specimens.
RESULTS
A positive result for the 16S ribosomal ribonucleic acid (rRNA) gene primer was observed only in two examined specimens of all the samples of the apical portion of the root canals in the present study. Negative result was shown by all the control group specimens, which were sterile samples. Presence of bacteria was confirmed by PCR in 38 out of 40 examined specimens. Amount of bacterial taxa, out of these 24 samples, ranged up to 6. Pseudoramibacter alactolyticus, Porphyromonas endodontalis, Dialister oral species, Bacteroidetes species, Streptococcus species, Olsenella uli, Synergistes species, Fusobacterium nucleatum, Parvimonas micra, Treponema denticola, and Filifactor alocis were the specific species detected. Bacteroidetes species was the only species that were detected at levels at or above 10. Heavy bacterial infections were noticed in more than 45% of the cases at the periradicular part of the root canals.
CONCLUSION
Microbial flora of the apical segment of the root with necrotized pulp tissue comprises a vast variety of pathogenic bacteria.
CLINICAL SIGNIFICANCE
For better prognosis of the treatment of such cases, adequate knowledge of the microbial flora of the root, especially the apical portion is necessary.
Topics: Bacteroidetes; Fusobacterium nucleatum; Humans; Periapical Periodontitis; Polymerase Chain Reaction; Porphyromonas endodontalis; RNA, Ribosomal, 16S; Streptococcus; Tooth Apex; Tooth Root; Treponema denticola
PubMed: 28050984
DOI: 10.5005/jp-journals-10024-1986 -
Anaerobe Apr 2017Strain KHD7, a Gram-stain-positive rod-shaped, non-sporulating, strictly anaerobic bacterium, was isolated from the vaginal swab of a woman with bacterial vaginosis. We...
Strain KHD7, a Gram-stain-positive rod-shaped, non-sporulating, strictly anaerobic bacterium, was isolated from the vaginal swab of a woman with bacterial vaginosis. We studied its phenotypic characteristics and sequenced its complete genome. The major fatty acids were C16:0 (44%), C18:2n6 (22%), and C18:1n9 (14%). The 1,806,744 bp long genome exhibited 49.24% G+C content; 1549 protein-coding and 51 RNA genes. Strain KHD7 exhibited a 93.5% 16S rRNA similarity with Olsenella uli, the phylogenetically closest species in the family Coriobacteriaceae. Therefore, strain KHD7 is sufficiently distinct to represent a new genus, for which we propose the name Olegusella massiliensis gen. nov., sp. nov. The type strain is KHD7.
Topics: Actinobacteria; Adult; Anaerobiosis; Bacterial Typing Techniques; Base Composition; Cluster Analysis; Cytosol; DNA, Bacterial; DNA, Ribosomal; Fatty Acids; Female; Genome, Bacterial; Humans; Microscopy; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Vagina; Vaginosis, Bacterial
PubMed: 28223255
DOI: 10.1016/j.anaerobe.2017.02.012