scholarly journals A Linear Plasmid-Like Prophage of Actinomyces odontolyticus Promotes Biofilm Assembly

2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Mengyu Shen ◽  
Yuhui Yang ◽  
Wei Shen ◽  
Lujia Cen ◽  
Jeffrey S. McLean ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Human Microbiome ◽  
Genomic Analysis ◽  
Electron Microscopic Examination ◽  
Oral Microbiome ◽  
Extracellular Dna ◽  
Linear Plasmid ◽  
Electron Microscopic ◽  
Content Type ◽  
Human Oral Cavity

ABSTRACT 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 Actinomyces odontolyticus subsp. actinosynbacter 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 A. odontolyticus. 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 Siphoviridae 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 A. odontolyticus, which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity. IMPORTANCE 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, Actinomyces odontolyticus subsp. actinosynbacter 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 A. odontolyticus within the oral cavity.

Progression of partial experimental injury to peripheral nerve

1975 ◽  
Vol 42 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Alan R. Hudson ◽  
David G. Kline
Keyword(s):  
Recovery Of Function ◽  
Electron Microscopic Examination ◽  
Ground Substance ◽  
Electron Microscopic ◽  
Early Recovery ◽  
Content Type ◽  
Proximal Stimulus ◽  
Late Recovery ◽  
Fine Print ◽  
Experimental Injury

✓ Biopsies from partially lacerated nerves were taken at the sites of proximal stimulus, laceration, and distal recording, and from stimuli and recording sites of control nerves. Electron microscopic examination of the partially lacerated major fasciculus revealed three zones of injury. The laceration zone showed neurotemetic changes, the adjacent or intermediate zone, partial degeneration, and the zone most peripheral to the laceration, changes in ground substance. Progression of the original injury is apparently due to ongoing changes in the intermediate and peripheral zones while much of the relative early recovery is due to reversal of changes in these zones. Regeneration through the laceration or neurotemetic zone is limited but does account for a small amount of late recovery of function.

scholarly journals Targeting the HUβ Protein PreventsPorphyromonas gingivalisfrom Entering into Preexisting Biofilms

2018 ◽  
Vol 200 (11) ◽  
pp. e00790-17 ◽  
Author(s):  
Christopher J. Rocco ◽  
Lauren O. Bakaletz ◽  
Steven D. Goodman
Keyword(s):  
Oral Cavity ◽  
Periodontal Disease ◽  
Porphyromonas Gingivalis ◽  
The United States ◽  
Extracellular Dna ◽  
Bacterial Biofilms ◽  
Oral Streptococci ◽  
Content Type ◽  
Oral Streptococcus ◽  
Streptococcal Species

ABSTRACTThe oral cavity is home to a wide variety of bacterial species, both commensal, such as various streptococcal species, and pathogenic, such asPorphyromonas gingivalis, one of the main etiological agents of periodontal disease. Our understanding of how these bacteria ultimately cause disease is highly dependent upon understanding how they coexist and interact with one another in biofilm communities and the mechanisms by which biofilms are formed. Our research has demonstrated that the DNABII family of DNA-binding proteins are important components of the extracellular DNA (eDNA)-dependent matrix of bacterial biofilms and that sequestering these proteins via protein-specific antibodies results in the collapse of the biofilm structure and release of the resident bacteria. While the high degree of similarity among the DNABII family of proteins has allowed antibodies derived against specific DNABII proteins to disrupt biofilms formed by a wide range of bacterial pathogens, the DNABII proteins ofP. gingivalishave proven to be antigenically distinct, allowing us to determine if we can use anti-P. gingivalisHUβ antibodies to specifically target this species for removal from a mixed-species biofilm. Importantly, despite forming homotypic biofilmsin vitro,P. gingivalismust enter preexisting biofilmsin vivoin order to persist within the oral cavity. The data presented here indicate that antibodies derived against theP. gingivalisDNABII protein, HUβ, reduce by half the amount ofP. gingivalisorganisms entering into preexisting biofilm formed by four oral streptococcal species. These results support our efforts to develop methods for preventing and treating periodontal disease.IMPORTANCEPeriodontitis is one of the most prevalent chronic infections, affecting 40 to 50% of the population of the United States. The root cause of periodontitis is the presence of bacterial biofilms within the gingival space, withPorphyromonas gingivalisbeing strongly associated with the development of the disease. Periodontitis also increases the risk of secondary conditions and infections such as atherosclerosis and infective endocarditis caused by oral streptococci. To induce periodontitis,P. gingivalisneeds to incorporate into preformed biofilms, with oral streptococci being important binding partners. Our research demonstrates that targeting DNABII proteins with an antibody disperses oral streptococcus biofilm and preventsP. gingivalisentry into oral streptococcus biofilm. These results suggest potential therapeutic treatments for endocarditis caused by streptococci as well as periodontitis.

Ultrastructural morphology of the olfactory pathway for cerebrospinal fluid drainage in the rabbit

1986 ◽  
Vol 64 (3) ◽  
pp. 466-473 ◽  
Author(s):  
Stephanie S. Erlich ◽  
J. Gordon McComb ◽  
Shigeyo Hyman ◽  
Martin H. Weiss
Keyword(s):  
Cerebrospinal Fluid ◽  
Connective Tissue ◽  
Electron Microscopic Examination ◽  
Olfactory Pathway ◽  
Electron Microscopic ◽  
En Bloc ◽  
Major Pathway ◽  
Content Type ◽  
Csf Drainage ◽  
Fine Print

✓ Previous physiological studies indicate that the olfactory region serves as a major pathway for cerebrospinal fluid (CSF) drainage into the lymphatic system. The present study was undertaken to determine the ultrastructural characteristics of this egress route. New Zealand White rabbits received a single bolus injection of the tracer ferritin (MW 400,000) into both lateral ventricles in such a manner as not to raise the intraventricular pressure above the normal level. The animals were sacrificed via intracardiac perfusion of fixative between less than 12 minutes and 4 hours following injection. The cribriform region was removed en bloc, decalcified, sectioned coronally, and prepared for light and electron microscopic examination. The arachnoid, dura, and periosteum surrounding the fila olfactoria passing through the cribriform plate merge together and form the perineurium, which consists of multiple layers of loosely overlapping cells with widely separated junctions and few vesicles. The perineurium surrounding the olfactory filaments at the superficial submucosal level is only one cell thick. The subarachnoid space freely communicates with the perineural space surrounding each filament. No morphological barrier between the perineural space and the loose submucosal connective tissue was identified. Whether or not the perineurium was multi- or singlelayered, ferritin was noted in abundance between the loosely overlapping perineural cells and in the submucosal connective tissue. The distribution of ferritin at 12 minutes was similar to that at 4 hours; however, the quantity of ferritin was increased at 4 hours. These results indicate that no significant barrier to CSF drainage is present at the rabbit cribriform region and that CSF reaches the submucosal region rapidly via open pathways.

Multiple supratentorial hemangioblastomas

1971 ◽  
Vol 35 (4) ◽  
pp. 396-405 ◽  
Author(s):  
Shakuntla Ishwar ◽  
Raymond M. Taniguchi ◽  
F. Stephen Vogel
Keyword(s):  
Secretory Granules ◽  
Electron Microscopic Examination ◽  
Extramedullary Hematopoiesis ◽  
Electron Microscopic ◽  
Content Type ◽  
Parietal Area ◽  
Erythropoietin Production ◽  
Well Differentiated ◽  
The Right ◽  
Mass Lesions

✓ Multiple hemangioblastomas were found above the tentorium in a 62-year-old woman who first had a discrete 2.5 cm tumor removed from the superior aspect of the tentorium adjacent to the falx, and 2 years later developed two more intracranial mass lesions, one in the right parietal area, the other attached to the dura of the right frontal fossa. Histological examination of all three tumors showed precisely the same well-differentiated morphology of hemangioblastoma. Foci of extramedullary hematopoiesis were present within them. Electron microscopic examination of the last two lesions disclosed secretory granules within the tumor cells, indicative of erythropoietin production, as described previously in a hemangioblastoma. Collagen and endothelial cells were not present in quantities consistent with an angioblastic meningioma. The genesis of hemangioblastomas is discussed.

scholarly journals Description of Alloprevotella rava gen. nov., sp. nov., isolated from the human oral cavity, and reclassification of Prevotella tannerae Moore et al. 1994 as Alloprevotella tannerae gen. nov., comb. nov.

2013 ◽  
Vol 63 (Pt_4) ◽  
pp. 1214-1218 ◽  
Author(s):  
Julia Downes ◽  
Floyd E. Dewhirst ◽  
Anne C. R. Tanner ◽  
William G. Wade
Keyword(s):  
Oral Cavity ◽  
Type Strain ◽  
Type Species ◽  
Rrna Gene ◽  
The Novel ◽  
Content Type ◽  
Human Oral Cavity ◽  
Link Type ◽  
Prevotella Melaninogenica ◽  
The Family

Five strains of anaerobic, Gram-negative bacilli isolated from the human oral cavity were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group. Phylogenetic analysis of full-length 16S rRNA gene sequences showed that these strains represented a novel group within the family Prevotellaceae , and the most closely related species was Prevotella tannerae . P. tannerae and the novel taxon are deeply branched from the genus Prevotella , with sequence identities to the type strain of the type species of Prevotella , Prevotella melaninogenica , of 82.2 and 85.6 %, respectively. The novel genus Alloprevotella gen. nov. is proposed to accommodate the novel species Alloprevotella rava gen. nov., sp. nov. and the previously named Prevotella tannerae Moore et al. 1994 as Alloprevotella tannerae gen. nov., comb. nov. The type species is Alloprevotella tannerae. The type strain of Alloprevotella rava is 81/4-12T ( = DSM 22548T  = CCUG 58091T) and the type strain of Alloprevotella tannerae is ATCC 51259T  = CCUG 34292T  = CIP 104476T  = NCTC 13073T. Alloprevotella rava is weakly to moderately saccharolytic and produces moderate amounts of acetic acid and major amounts of succinic acid as end products of fermentation. Strains are sensitive to 20 % bile and hydrolyse gelatin. The principal cellular long-chain fatty acids are anteiso-C15 : 0, iso-C15 : 0, C16 : 0, iso-C17 : 0 and iso-C17 : 0 3-OH. The G+C content of the DNA of the type strain is 47 mol%.

scholarly journals Site-specificity of streptococci in the oral microbiome

2021 ◽  
Author(s):  
Anthony R. McLean ◽  
Julian Torres-Morales ◽  
Gary G. Borisy ◽  
Jessica L. Mark Welch
Keyword(s):  
Oral Cavity ◽  
Related Species ◽  
Oral Microbiome ◽  
Individual Species ◽  
Rrna Gene ◽  
Site Specificity ◽  
Oral Streptococci ◽  
Closely Related Species ◽  
Streptococcus Species ◽  
Human Oral Cavity

Patterns of microbial distribution are determined by as-yet poorly understood rules governing where microbes can grow and thrive. Therefore, a detailed understanding of where bacteria localize is necessary to advance microbial ecology and microbiome-based therapeutics. The site-specialist hypothesis predicts that most microbes in the human oral cavity have a primary habitat within the mouth where they are most abundant. We asked whether this hypothesis accurately describes the distribution of the members of the genus Streptococcus, a clinically relevant taxon that dominates most oral sites. Prior analysis of 16S rRNA gene sequencing data indicated that some oral Streptococcus clades are site-specialists while others may be generalists. However, within complex microbial populations composed of numerous closely-related species and strains, such as the oral streptococci, genome-scale analysis is necessary to provide the resolution to discriminate closely related taxa with distinct functional roles. Here we assess whether individual species within this genus are generalists using publicly available genomic sequence data that provides species-level resolution. We chose a set of high-quality representative genomes for Streptococcus species from the human oral microbiome. Onto these genomes, we mapped short-read metagenomic sequences from supragingival plaque, tongue dorsum, and other sites in the oral cavity. We found that every reliably detectable Streptococcus species in the human oral cavity was a site-specialist and that even closely related species such as S. mitis, S. oralis, and S. infantis specialized in different sites. These findings indicate that closely related bacteria can have distinct habitat distributions in the absence of dispersal limitation and under similar environmental conditions and immune regimes. These three species also share substantially the same species-specific core genes indicating that neither taxonomy nor gene content are clear predictors of site-specialization. Site-specificity may instead be influenced by subtle characteristics such as nucleotide-level divergences within conserved genes.

scholarly journals Veillonellae: Beyond Bridging Species in Oral Biofilm Ecology

2021 ◽  
Vol 2 ◽  
Author(s):  
Peng Zhou ◽  
Daniel Manoil ◽  
Georgios N. Belibasakis ◽  
Georgios A. Kotsakis
Keyword(s):  
Oral Cavity ◽  
Bacterial Species ◽  
Oral Microbiome ◽  
Future Research ◽  
Great Promise ◽  
Large Species ◽  
Oral Biofilm ◽  
Human Oral Cavity ◽  
Oral Biofilms ◽  
Polymicrobial Disease

The genus Veillonella comprises 16 characterized species, among which eight are commonly found in the human oral cavity. The high abundance of Veillonella species in the microbiome of both supra- and sub-gingival biofilms, and their interdependent relationship with a multitude of other bacterial species, suggest veillonellae to play an important role in oral biofilm ecology. Development of oral biofilms relies on an incremental coaggregation process between early, bridging and later bacterial colonizers, ultimately forming multispecies communities. As early colonizer and bridging species, veillonellae are critical in guiding the development of multispecies communities in the human oral microenvironment. Their ability to establish mutualistic relationships with other members of the oral microbiome has emerged as a crucial factor that may contribute to health equilibrium. Here, we review the general characteristics, taxonomy, physiology, genomic and genetics of veillonellae, as well as their bridging role in the development of oral biofilms. We further discuss the role of Veillonella spp. as potential “accessory pathogens” in the human oral cavity, capable of supporting colonization by other, more pathogenic species. The relationship between Veillonella spp. and dental caries, periodontitis, and peri-implantitis is also recapitulated in this review. We finally highlight areas of future research required to better understand the intergeneric signaling employed by veillonellae during their bridging activities and interspecies mutualism. With the recent discoveries of large species and strain-specific variation within the genus in biological and virulence characteristics, the study of Veillonella as an example of highly adaptive microorganisms that indirectly participates in dysbiosis holds great promise for broadening our understanding of polymicrobial disease pathogenesis.

scholarly journals Sharing of Prey: Coinfection of a Bacterium by a Virus and a Prokaryotic Predator

mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Huan Chen ◽  
Henry N. Williams
Keyword(s):  
Vibrio Vulnificus ◽  
Electron Microscopic Examination ◽  
Dual Infection ◽  
New Paradigm ◽  
Electron Microscopic ◽  
Prey Cell ◽  
Bacterial Populations ◽  
Short Supply ◽  
Content Type ◽  
Predatory Prokaryotes

ABSTRACTRarely, if ever, has a single bacterial cell been confirmed to simultaneously host two fundamentally different predators. Two such predators are viruses and the predatory prokaryotes known asBdellovibrioand like organisms. Viruses or bacteriophage are particles requiring prey cells in an active metabolic state to complete their life cycle. TheBdellovibrioand like organisms, unlike viruses, are bacteria that can efficiently infect and grow in prey which are in stationary phase. In this study, electron microscopic examination revealed an unprecedented coinfection by the two agents ofVibrio vulnificus, introducing a new bacterial predation paradigm. Rather than the viruses andBdellovibrioand like organisms competing for a single prey cell, both can survive in the same cell and successfully reproduce themselves. This is an especially valuable mechanism when the prey is in short supply, and the survival of the predators may be at stake.IMPORTANCEThis article describes the coinfection of a prokaryotic prey or host cell by both a bacteriophage (phage) and the predatory bacterium of the groupBdellovibrioand like organisms (BALOs). Such coinfection has not been previously reported and therefore introduces a new paradigm for predation of bacteria. This finding invites new studies on the interactions of BALOs, phage, and prey in predation. Predation is an important mechanism in nature for helping to keep bacterial populations in check and also plays a major role in the cycling of nutrients through the microbial loop. How dual infection by phage and BALOs imposes on these and other functions of predation is fertile ground for future studies and serves as a keystone reference on bacterial predation and mortality.

scholarly journals Genome Sequence of the Bacteriocin-Producing Oral Probiotic Streptococcus salivarius Strain M18

2011 ◽  
Vol 193 (22) ◽  
pp. 6402-6403 ◽  
Author(s):  
Nicholas C. K. Heng ◽  
Nurul S. Haji-Ishak ◽  
Alaina Kalyan ◽  
Andrew Y. C. Wong ◽  
Marija Lovrić ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Genome Sequence ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Streptococcus Salivarius ◽  
Gram Positive ◽  
Content Type ◽  
Human Oral Cavity

Streptococcus salivarius is a Gram-positive bacterial commensal and pioneer colonizer of the human oral cavity. Many strains produce ribosomally synthesized proteinaceous antibiotics (bacteriocins), and some strains have been developed for use as oral probiotics. Here, we present the draft genome sequence of the bacteriocin-producing oral probiotic S. salivarius strain M18.

scholarly journals Molecular profiling of microbiota in human oral cavity, stomach and intestine

2018 ◽  
Author(s):  
Qianqian Liu ◽  
Feizhou Zhu ◽  
Liyu Chen ◽  
Meihua Xu ◽  
Jianwei Chen ◽  
...  
Keyword(s):  
16S Rrna ◽  
Oral Cavity ◽  
16S Rrna Gene ◽  
Gastric Juice ◽  
Human Microbiome ◽  
Human Microbiome Project ◽  
Rrna Gene ◽  
Human Oral Cavity ◽  
Stool Microbiota ◽  
The 16S Rrna Gene

The microbiota in the human gut is not only a complicated microecological system but also plays important roles in both health and disease. In order to understand the roles of these gut bacteria, we determined the distribution of microbiota in different regions of the gut by sequencing the 16S rRNA gene V4 region of the bacteria in the saliva, gastric juice, and stool of healthy individuals. The 16S rRNA gene V3-V5 region sequences of saliva and stool microbiota were obtained from Human Microbiome Project (HMP) and the V4 sequence was obtained from the V3-V5 sequences by a program designed by Perl language. We found that the microbiota of the gastric juice is more similar to those in the saliva rather than that in the stool. The frequency of some taxa was significantly different among the three groups with the Streptococcus, Veillonella, Oribacterium, Selenomonas, Actinomyces, and Granulicatella most abundant in the saliva; the Prevotella, Neisseria, Actinobacillus, Treponema, and Helicobacter most abundant in the gastric juice; and the Bacteroides, Parabacteroides, Faecalibacterium, Sutterella, Ruminococcus, Oscillospira and Phascolarctobacterium most abundant in the stool. In addition, results from PICRUSt analyses suggest that the functions of microbiota in the gastric juice are more similar as those in the saliva than in the stool. Moreover, we also found that the membrane transport of the microbiota in the saliva is higher than that in the stool and gastric juice. To our knowledge, this is the first comprehensive comparison of microbiota in the human oral cavity, stomach, and intestine.

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