scholarly journals Single-Cell Genomics and the Oral Microbiome

2020 ◽  
Vol 99 (6) ◽  
pp. 613-620 ◽  
Author(s):  
M. Balachandran ◽  
K.L. Cross ◽  
M. Podar

The human oral cavity is one of the first environments where microbes have been discovered and studied since the dawn of microbiology. Nevertheless, approximately 200 types of bacteria from the oral microbiota have remained uncultured in the laboratory. Some are associated with a healthy oral microbial community, while others are linked to oral diseases, from dental caries to gum disease. Single-cell genomics has enabled inferences on the physiology, virulence, and evolution of such uncultured microorganisms and has further enabled isolation and cultivation of several novel oral bacteria, including the discovery of novel interspecies interactions. This review summarizes some of the more recent advances in this field, which is rapidly moving toward physiologic characterization of single cells and ultimately cultivation of the yet uncultured. A combination of traditional microbiological approaches with genomic-based physiologic predictions and isolation strategies may lead to the oral microbiome being the first complex microbial community to have all its members cultivable in the laboratory. Studying the biology of the individual microbes when in association with other members of the community, in controlled laboratory conditions and in vivo, should lead to a better understanding of oral dysbiosis and its prevention and reversion.

2006 ◽  
Vol 73 (2) ◽  
pp. 630-636 ◽  
Author(s):  
Natalia I. Chalmers ◽  
Robert J. Palmer ◽  
Laurence Du-Thumm ◽  
Richard Sullivan ◽  
Wenyuan Shi ◽  
...  

ABSTRACT Oral biofilms are multispecies communities, and in their nascent stages of development, numerous bacterial species engage in interspecies interactions. Better insight into the spatial relationship between different species and how species diversity increases over time can guide our understanding of the role of interspecies interactions in the development of the biofilms. Quantum dots (QD) are semiconductor nanocrystals and have emerged as a promising tool for labeling and detection of bacteria. We sought to apply QD-based primary immunofluorescence for labeling of bacterial cells with in vitro and in vivo biofilms and to compare this approach with the fluorophore-based primary immunofluorescence approach we have used previously. To investigate QD-based primary immunofluorescence as the means to detect distinct targets with single-cell resolution, we conjugated polyclonal and monoclonal antibodies to the QD surface. We also conducted simultaneous QD conjugate-based and fluorophore conjugate-based immunofluorescence and showed that these conjugates were complementary tools in immunofluorescence applications. Planktonic and biofilm cells were labeled effectively by considering two factors: the final nanomolar concentration of QD conjugate and the amount of antibody conjugated to the QD, which we define as the degree of labeling. These advances in the application of QD-based immunofluorescence for the study of biofilms in vitro and in vivo will help to define bacterial community architecture and to facilitate investigations of interactions between bacterial species in these communities.


Author(s):  
Ciro Gargiulo Isacco ◽  
Andrea Ballini ◽  
Danila De Vito ◽  
Kieu Cao Diem Nguyen ◽  
Stefania Cantore ◽  
...  

: The current treatment and prevention of oral disorders follow a very sectoral control and procedures considering mouth and its structures as system completely independent from the rest of the body. The main therapeutic approach is carried out on just to keep the levels of oral bacteria and hygiene in an acceptable range compatible with one-way vision of oral-mouth health completely separated from a systemic microbial homeostasis (eubiosis vs dysbiosis). This can negatively impact on the diagnosis of more complex systemic disease and its progression. Dysbiosis is consequence of oral and gut microbiota unbalance with consequences, as reported in current literature, in cardio vascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer’s disease. Likewise, there is the need to highlight and develop a novel philosophical approach in the treatments for oral diseases that will necessarily involve non-conventional approaches.


2021 ◽  
Vol 9 (8) ◽  
pp. 1657
Author(s):  
Anders Esberg ◽  
Linda Johansson ◽  
Ingegerd Johansson ◽  
Solbritt Rantapää Dahlqvist

Rheumatoid arthritis (RA) is the most common autoimmune inflammatory disease, and single periodontitis-associated bacteria have been suggested in disease manifestation. Here, the oral microbiota was characterized in relation to the early onset of RA (eRA) taking periodontal status into consideration. 16S rRNA gene amplicon sequencing of saliva bacterial DNA from 61 eRA patients without disease-modifying anti-rheumatic drugs and 59 matched controls was performed. Taxonomic classification at 98.5% was conducted against the Human Oral Microbiome Database, microbiota functions were predicted using PICRUSt, and periodontal status linked from the Swedish quality register for clinically assessed caries and periodontitis. The participants were classified into three distinct microbiota-based cluster groups with cluster allocation differences by eRA status. Independently of periodontal status, eRA patients had enriched levels of Prevotella pleuritidis, Treponema denticola, Porphyromonas endodontalis and Filifactor alocis species and in the Porphyromonas and Fusobacterium genera and functions linked to ornithine metabolism, glucosylceramidase, beta-lactamase resistance, biphenyl degradation, fatty acid metabolism and 17-beta-estradiol-17-dehydrogenase metabolism. The results support a deviating oral microbiota composition already in eRA patients compared with healthy controls and highlight a panel of oral bacteria that may be useful in eRA risk assessment in both periodontally healthy and diseased persons.


2021 ◽  
Author(s):  
Alba Regueira-Iglesias ◽  
Lara Vazquez-Gonzalez ◽  
Carlos Balsa-Castro ◽  
Triana Blanco-Pintos ◽  
Victor Manuel Arce ◽  
...  

This in silico investigation aimed to: 1) evaluate a set of primer pairs with high coverage, including those most commonly used in the literature, to find the different oral species with 16S rRNA gene amplicon similarity/identity (ASI) values ≥97%; and 2) identify oral species that may be erroneously clustered in the same operational taxonomic unit (OTU) and ascertain whether they belong to distinct genera or other higher taxonomic ranks. Thirty-nine primer pairs were employed to obtain amplicon sequence variants (ASVs) from the complete genomes of 186 bacterial and 135 archaeal species. For each primer, ASVs without mismatches were aligned using BLASTN and their similarity values were obtained. Finally, we selected ASVs from different species with an ASI value ≥97% that were covered 100% by the query sequences. For each primer, the percentage of species-level coverage with no ASI≥97% (SC-NASI≥97%) was calculated. Based on the SC-NASI≥97% values, the best primer pairs were OP_F053-KP_R020 for bacteria (65.05%), KP_F018-KP_R002 for archaea (51.11%), and OP_F114-KP_R031 for bacteria and archaea together (52.02%). Eighty percent of the oral-bacteria and oral-archaea species shared an ASI≥97% with at least one other taxa, including Campylobacter, Rothia, Streptococcus, and Tannerella, which played conflicting roles in the oral microbiota. Moreover, around a quarter and a third of these two-by-two similarity relationships were between species from different bacteria and archaea genera, respectively. Furthermore, even taxa from distinct families, orders, and classes could be grouped in the same cluster. Consequently, irrespective of the primer pair used, OTUs constructed with a 97% similarity provide an inaccurate description of oral-bacterial and oral-archaeal species, greatly affecting microbial diversity parameters. As a result, clustering by OTUs impacts the credibility of the associations between some oral species and certain health and disease conditions. This limits significantly the comparability of the microbial diversity findings reported in oral microbiome literature.


2021 ◽  
Vol 12 ◽  
Author(s):  
Irene Soffritti ◽  
Maria D’Accolti ◽  
Chiara Fabbri ◽  
Angela Passaro ◽  
Roberto Manfredini ◽  
...  

The human oral microbiome (HOM) is the second largest microbial community after the gut and can impact the onset and progression of several localized and systemic diseases, including those of viral origin, especially for viruses entering the body via the oropharynx. However, this important aspect has not been clarified for the new pandemic human coronavirus SARS-CoV-2, causing COVID-19 disease, despite it being one of the many respiratory viruses having the oropharynx as the primary site of replication. In particular, no data are available about the non-bacterial components of the HOM (fungi, viruses), which instead has been shown to be crucial for other diseases. Consistent with this, this study aimed to define the HOM in COVID-19 patients, to evidence any association between its profile and the clinical disease. Seventy-five oral rinse samples were analyzed by Whole Genome Sequencing (WGS) to simultaneously identify oral bacteria, fungi, and viruses. To correlate the HOM profile with local virus replication, the SARS-CoV-2 amount in the oral cavity was quantified by digital droplet PCR. Moreover, local inflammation and secretory immune response were also assessed, respectively by measuring the local release of pro-inflammatory cytokines (L-6, IL-17, TNFα, and GM-CSF) and the production of secretory immunoglobulins A (sIgA). The results showed the presence of oral dysbiosis in COVID-19 patients compared to matched controls, with significantly decreased alpha-diversity value and lower species richness in COVID-19 subjects. Notably, oral dysbiosis correlated with symptom severity (p = 0.006), and increased local inflammation (p < 0.01). In parallel, a decreased mucosal sIgA response was observed in more severely symptomatic patients (p = 0.02), suggesting that local immune response is important in the early control of virus infection and that its correct development is influenced by the HOM profile. In conclusion, the data presented here suggest that the HOM profile may be important in defining the individual susceptibility to SARS-CoV-2 infection, facilitating inflammation and virus replication, or rather, inducing a protective IgA response. Although it is not possible to determine whether the alteration in the microbial community is the cause or effect of the SARS-CoV-2 replication, these parameters may be considered as markers for personalized therapy and vaccine development.


2019 ◽  
Vol 7 (4) ◽  
pp. 120-124
Author(s):  
Roshna M. Qadir ◽  
Mahde S. Abdulrahman

Obesity represents one of the major problematic health issues worldwide. Recent evidences suggest that obesity is related with the alteration of the oral microbiome. The aim of this study was to measure the salivary bacterial Selenomonas noxia in Duhok population. A total of 155 saliva samples were collected from individuals (aged between 19-35 years) of both genders (86 females and 69 males). The individuals were divided into three groups (obese, overweight, and normal weight) based on their body mass index. Bacterial genomic DNA was extracted from saliva samples. Molecular detections of Selenomonas noxia were performed by the polymerase chain reaction. Among the 155 participants, 34.1% were obese, 26.4% overweight and 39.3% normal weight individuals. The prevalence rate of oral S. noxia among all people was 82.6%. The highest rate of S. noxia was in obese people (86.8%), followed by overweight (85.4%) and normal weight people (77%). The prevalence of S. noxia in overweight people was statistically significant in compare with the normal weight people (p<0.0001). Moreover, the oral carriage of S. noxia was highest among the overweight females (94.5%) followed by obese females (88.9%). However, no significant difference was found compared to males. The result revealed that it is possible to assume that the expansion of S. noxia in saliva is due to obesity. Moreover, the composition of salivary microbiome may lead to the risk that the overweight group is at risk of future obesity. However, further investigations are required with larger sample and participants with different socioeconomic status in order to address the exact link between obesity and oral bacteria. This could lead to a new and promising therapeutic way for improving human's health.  


Author(s):  
Liang Ren ◽  
Daonan Shen ◽  
Chengcheng Liu ◽  
Yi Ding

The human oral cavity harbors approximately 1,000 microbial species, and dysbiosis of the microflora and imbalanced microbiota-host interactions drive many oral diseases, such as dental caries and periodontal disease. Oral microbiota homeostasis is critical for systemic health. Over the last two decades, bacterial protein phosphorylation systems have been extensively studied, providing mounting evidence of the pivotal role of tyrosine and serine/threonine phosphorylation in oral bacterial dysbiosis and bacteria-host interactions. Ongoing investigations aim to discover novel kinases and phosphatases and to understand the mechanism by which these phosphorylation events regulate the pathogenicity of oral bacteria. Here, we summarize the structures of bacterial tyrosine and serine/threonine kinases and phosphatases and discuss the roles of tyrosine and serine/threonine phosphorylation systems in Porphyromonas gingivalis and Streptococcus mutans, emphasizing their involvement in bacterial metabolism and virulence, community development, and bacteria-host interactions.


2017 ◽  
Vol 114 (18) ◽  
pp. E3659-E3668 ◽  
Author(s):  
Ann Wiegand ◽  
Jonathan Spindler ◽  
Feiyu F. Hong ◽  
Wei Shao ◽  
Joshua C. Cyktor ◽  
...  

Little is known about the fraction of human immunodeficiency virus type 1 (HIV-1) proviruses that express unspliced viral RNA in vivo or about the levels of HIV RNA expression within single infected cells. We developed a sensitive cell-associated HIV RNA and DNA single-genome sequencing (CARD-SGS) method to investigate fractional proviral expression of HIV RNA (1.3-kb fragment of p6, protease, and reverse transcriptase) and the levels of HIV RNA in single HIV-infected cells from blood samples obtained from individuals with viremia or individuals on long-term suppressive antiretroviral therapy (ART). Spiking experiments show that the CARD-SGS method can detect a single cell expressing HIV RNA. Applying CARD-SGS to blood mononuclear cells in six samples from four HIV-infected donors (one with viremia and not on ART and three with viremia suppressed on ART) revealed that an average of 7% of proviruses (range: 2–18%) expressed HIV RNA. Levels of expression varied from one to 62 HIV RNA molecules per cell (median of 1). CARD-SGS also revealed the frequent expression of identical HIV RNA sequences across multiple single cells and across multiple time points in donors on suppressive ART consistent with constitutive expression of HIV RNA in infected cell clones. Defective proviruses were found to express HIV RNA at levels similar to those proviruses that had no obvious defects. CARD-SGS is a useful tool to characterize fractional proviral expression in single infected cells that persist despite ART and to assess the impact of experimental interventions on proviral populations and their expression.


2020 ◽  
Vol 10 (2) ◽  
pp. 35
Author(s):  
Romeo Patini

For years, it has been thought that the field of dentistry was referring exclusively to some diseases that strictly affect the oral cavity. Dental caries, periodontal disease, and pathologies associated with their worsening were considered almost the only interest in scientific research in dentistry. Recent studies have begun to shed light on the effect of the oral microbiota on general health and on the crucial role of dentistry in its maintenance. In this way, we came to understand that the bacterial populations that make up the oral microbiota can vary profoundly between individuals and that contribute in a fundamental way to outlining the so-called “oral signature”. This characteristic is called into question to evaluate the susceptibility, or lack thereof, of the subject to the contraction of a wide range of pathologies, apparently not connected with oral health. From this evidence, it will also be possible to study therapeutic approaches aimed at the eradication of species considered at risk or colonization with species considered protective; thus, giving life to so-called “personalized dentistry”. Therefore, this Special Issue is aimed at spreading the scientific knowledge over the current limits in terms of new molecular and culturomic approaches towards the diagnosis of oral microbiota and the treatment techniques of eventually associated systemic diseases. In vivo studies and systematic literature reviews with quantitative analysis of results, when possible, will be given a high priority.


2011 ◽  
Vol 78 (1) ◽  
pp. 194-203 ◽  
Author(s):  
M. V. Sizova ◽  
T. Hohmann ◽  
A. Hazen ◽  
B. J. Paster ◽  
S. R. Halem ◽  
...  

ABSTRACTA significant number of microorganisms from the human oral cavity remain uncultivated. This is a major impediment to the study of human health since some of the uncultivated species may be involved in a variety of systemic diseases. We used a range of innovations previously developed to cultivate microorganisms from the human oral cavity, focusing on anaerobic species. These innovations include (i)in vivocultivation to specifically enrich for species actively growing in the oral cavity (the “minitrap” method), (ii) single-cell long-term cultivation to minimize the effect of fast-growing microorganisms, and (iii) modifications of conventional enrichment techniques, using media that did not contain sugar, including glucose. To enable cultivation of obligate anaerobes, we maintained strict anaerobic conditions in most of our cultivation experiments. We report that, on a per cell basis, the most successful recovery was achieved using minitrap enrichment (11%), followed by single-cell cultivation (3%) and conventional plating (1%). Taxonomically, the richest collection was obtained using the single-cell cultivation method, followed by minitrap and conventional enrichment, comprising representatives of 13, 9, and 4 genera, respectively. Interestingly, no single species was isolated by all three methods, indicating method complementarity. An important result is the isolation and maintenance in pure culture of 10 strains previously only known by their molecular signatures, as well as representatives of what are likely to be three new microbial genera. We conclude that the ensemble of new methods we introduced will likely help close the gap between cultivated and uncultivated species from the human oral cavity.


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