Prior studies have shown that the low-level microbiome in the placenta is most similar to the non-pregnant oral microbiome, suggesting a hematogenous route of bacterial transmission. Based on these studies, we theorized that a disruption of the normal balance of pathogenic and commensal microorganisms in the oral cavity will lead to conditions that favor colonization of the placenta and amniotic cavity, leading to inflammation and preterm birth. We hypothesized that an altered oral microbiome profile will promote preterm birth. Our study aimed to compare metagenomic profiles of saliva and tongue in women delivering preterm to those of women delivering at term. Unstimulated saliva and tongue brushings were collected according to an IRB-approved protocol from patients who delivered preterm, and from age and race-matched patients who delivered at term. Exclusion criteria included obvious risk factors for preterm birth or other major complications (multiple gestation; history of or current cervical cerclage; history of hypertension or diabetes; prior history of preterm birth or preeclampsia; age less than 16 or greater than 45) as well as immunologic problems (HIV, organ transplant, etc). Oral samples were collected within 24-48 hours after delivery. Samples were analyzed using 16S rDNA-based sequencing, where the DNA was extracted and then amplified by PCR using 16S rDNA primers. Data was processed using the UPARSE/SINTAX pipeline, and differentially abundant taxa were determined using the LEfSe method and MaAsLin2. The parent study enrolled 100 patients who delivered preterm and 205 patients who delivered at term. A subset of patients had oral samples collected, and 95 saliva and 70 tongue samples were analyzed using 16S rDNA-based sequencing. Communities from tongue and saliva were significantly different between women who delivered preterm and those who delivered at term, although not between those delivering low birthweight versus normal birthweight infants. When assessing beta diversity using the unweighted unifrac metric, patients who delivered very preterm (VPT, < 32 weeks) had a tongue microbiome that was consistently and statistically different from the tongue microbiome of patients who delivered both term (T, > 37 weeks) and late preterm (LPT, 32-<37). Differences remained significant after controlling for tobacco use. In a three-way comparison of saliva samples between the groups using MaAsLin2, the genus Lachnoanaerobaculum was significantly less abundant in the VPT group. Our studies suggest a tongue and salivary microbiome that differs between women delivering term and late preterm versus very preterm. Future studies are required to prospectively confirm differences and may yield data to design noninvasive tests to predict preterm birth risk. / 2021-06-12T00:00:00Z

No description available.

The human oral microbiome is the total amount of microbial biodiversity present in the oral cavity and, given its relevance to human health and disease, has recently become a foci for study. By analyzing dental calculus, and sequencing the bacterial DNA, it is possible to reconstruct and examine the oral microbiomes of past individuals. In this study, dental calculus was sampled from (N=4) skeletons recovered from the cemetery of the mid 19th- 20th, century Mississippi State Asylum in Jackson, MS. Bacterial DNA isolation and shotgun sequencing were successful, with 16S analyses yielding an average of 96 identified species. All samples were significantly different from each other at all taxonomic levels (p <0.0001). Targeted examinations for opportunistically pathogenic oral bacteria were performed, but no detectable bacterial DNA was found in the samples. This study is the first to reconstruct the oral microbiomes of a subsample of an historic institutionalized population.

Analyses of human oral microbiomes reveal substantial amounts of information about health, diet, and diseases of individuals and their communities within the archaeological record. In order to examine bacterial genomes from the past, specific archaeological samples that contain remnants of the microbial communities in question must be utilized. Recent developments in high-throughput, next-generation DNA sequencing have enabled the characterization of entire oral microbiomes and genomes from the remains of the bacteria trapped in calcified dental plaque. This project analyzed samples of ancient human dental calculus from North and Central America, which were examined for the changes within the oral microbiome in relation to the adoption of agriculture. Additionally, the conditional presence of pathogens associated with an increasingly agricultural and carbohydrate-rich diet was examined. The overarching goal was to examine and determine the level of microbial shifts within the past oral microbiomes of North and Central America, and by virtue of using the associated archaeological reports and analyses, place the data into the proper context. Three distinct sets of dental calculus were used for this Dissertation; The first is from Indigenous samples (N=56), spanning from the Archaic to the Mississippian, recovered from excavations in the Guntersville Basin in Northern Alabama. The second set is from a Late-Terminal Classic Maya city center and satellite village in the Upper Belize Valley (N=11). The final sample set comes from an archaeologically recovered early 20th century Cemetery near Jackson Mississippi (N=12). After individual analyses, they are all examined along a temporal axis to examine the effect of agriculture on the human oral microbiome. The findings from this study have shown that oral microbiomes of the Americas were affected by the introduction of agriculture, but remained biologically diverse. Because various subsistence strategies can shape and affect the oral microbiome, the composition is seen to change over time. Our understanding of the evolution of oral microbiomes throughout human history is more complex than previously thought; there is no global trend for the oral microbiome, but is highly location dependent.

No description available.

No description available.

As fissuras orofaciais não-sindrômicas (FO-NS) correspondem a 70% de todos os casos de FO, possuem etiologia complexa e pouco compreendida, sendo consideradas de herança multifatorial com forte influência de fatores genéticos e ambientais. Apesar de estudos de análise de ligação e associação apontarem vários loci de susceptibilidade às FO-NS, o componente genético ainda não está totalmente explicado. Fatores ambientais também possuem um importante papel na etiologia das FO, e alguns já foram replicados em várias populações. Fatores como exposição materna ao álcool, drogas, tabaco, medicamentos, desnutrição e baixo nível socioeconômico são alguns dos fatores já associados a esta condição. As infecções periodontais são comuns em mulheres grávidas e estão associadas a parto prematuro, baixo peso fetal e, mais recentemente, foram reportadas como fator de risco aumentado para FO-NS nos fetos. Adicionalmente, o avanço das tecnologias de sequenciamento do DNA melhorou exponencialmente a compreensão do microbioma humano e sua influência no estado de saúde e doença, e, mais especificamente, o conhecimento sobre o impacto do microbioma na gravidez. O objetivo deste projeto foi identificar novos fatores etiológicos genéticos e ambientais das FO-NS. Para isso, primeiramente, sequenciamos 68 genes candidatos a FO por sequenciamento de nova geração em 193 indivíduos com FO-NS familial. Nós encontramos enriquecimento significativo de variantes raras e patogênicas de perda de função nos indivíduos com FO-NS e observamos que essas variantes estão em genes intolerantes a esse tipo de mutação. Também reportamos novas variantes raras do tipo perda de função no gene ARHGAP29 e sua importância na susceptibilidade as FO-NS familiais. Além disso, sugerimos o uso de um ponto de corte baseado no escore pLI do banco de dados ExAC como parâmetro para priorizar variantes em estudos de FO-NS familiares, assumindo modelo de herança mono ou oligogênico. Adicionalmente, estudamos o microbioma oral de mães de crianças com FO-NS e mães de crianças sem malformações, utilizando o sequenciamento da subunidade 16S do rRNA das bactérias com o objetivo de verificar diferenças consistentes na composição do microbioma oral de mães de crianças com FO-NS, levando em consideração a presença ou não de doenças infecciosas periodontais maternas. A casuística foi composta de 6 mães de recém-nascidos de até 1 mês que apresentaram FO-NS ao nascimento e mães de crianças sem qualquer malformação congênita. As análises de alfa e beta diversidades não demonstraram diferença significativa na composição do microbioma oral de mães de crianças com FO-NS e mães de crianças controle, contudo observamos que o grupo com infecções periodontais possui a diversidade taxonômica mais abundante do que o grupo hígido. Em resumo, nesse estudo piloto não foi possível identificar alterações no microbioma oral como um fator etiológico das FO-NS. Novas análises em uma casuística maior são necessárias para a confirmação desse achado / The non-syndromic orofacial clefts (nsOFC) correspond to 70% of all OFC cases, have complex etiology and are poorly understood, being considered multifactorial inheritance with a strong influence of genetic and environmental factors. Although linkage and association analysis studies point to several nsOFC susceptibility loci, the genetic component is not yet fully explained. Environmental factors also play an important role in OFC etiology, and some have been replicated in several populations. Factors such as maternal exposure to alcohol, drugs, tobacco, drugs, malnutrition and low socioeconomic status are some of the factors already associated with this condition. Periodontal infections are common in pregnant women and are associated with preterm birth, low birth weight and, more recently, have been reported as an increased risk factor for nsOFC in fetuses. Additionally, the advancement of DNA sequencing technologies has exponentially improved the understanding of the human microbiome and its influence on health and disease status, and, more specifically, knowledge about the impact of the microbiome on pregnancy. The objective of this project was to identify new genetic and environmental etiological factors of nsOFC. For this, we first sequenced 68 candidate genes by next generation sequencing in 193 individuals with familial nsOFC. We found significant enrichment of rare and pathogenic loss of function variants in individuals with nsOFC and we observed that these variants were in genes intolerant to this type of mutation. We also reported new rare loss-of-function variants in the ARHGAP29 gene and its importance in the liability of familial nsOFC. In addition, we suggested the use of a cutoff point based on the ExAC database pLI score as a parameter to prioritize variants in familial nsOFC studies, assuming a mono or oligogenic inheritance model. In addition, we studied the oral microbiome of 6 mothers of newborns up to 1-month-old with nsOFC and 6 mothers of newborns without congenital malformations using the 16S rRNA sequencing in order to verify consistent differences in the composition of the oral microbiome of mothers of children with nsOFC, taking into account the presence or absence of maternal periodontal infectious diseases. The analysis of alpha and beta diversities did not show a significant difference in the composition of the oral microbiome of mothers of nsOFC children and mothers of control children, however, we observed that the group with periodontal infectious diseases has more abundant taxonomic diversity than the healthy group. In summary, in this pilot study, it was not possible to identify alterations in the oral microbiome as an etiological factor of FO-NS. New analyzes in a larger cohort are necessary to confirm this finding

No description available.

Archaeological dental calculus represents a depositional environment that entraps oral microbes, and debris of dietary, environmental, and cultural material that entered the mouth throughout the host’s life. Hence, they represent valuable archives of information about the host’s lifestyle, health, and environment. The aim of this study was to identify if the farming transition and its’ associated change in diet composition, may have influenced species composition in the oral cavity. To shed some light into the evolution of ancient oral microbiomes from Africa, 3 novel Iron Age dental calculus metagenomes together with a comparative dataset of 18 archaeological dental calculus metagenomes from North African Upper Palaeolithic, Later Stone Age, Iron Age, and 18th-19th century populations where analysed. Shotgun sequencing data was used to reconstruct 21 oral metagenomes from the past 15,000 years. This study found an oral microbiome that has been maintained from the Upper Palaeolithic (North Africa) to the 19th Century. However, closer examination to the relative abundance of three keystone species of the subgingival plaque, portray a chronological evolution that reflects that of its host during the major dietary and cultural transition that occurred during the farming revolution in the Iron Age.

The human body is colonized by more than 100 trillion microbes which make up an essential part of the body and plays a significant role in health. We now know the over use and misuse of broad-spectrum antibiotics can disrupt this microbiome contributing to the onset of disease and runs the risk of promoting antibiotic resistance. With antibiotic research still on the decline, new strategies are greatly needed to combat emerging pathogens while maintaining a healthy microbiome. We therefore set out to present a novel species-selective antimicrobial drug discovery strategy. Disruption of the homeostasis within the oral cavity can trigger the onset of one of the most common bacterial infections, periodontal disease. Even though the oral cavity is one of the most diverse sites on the human body, the Gram-negative colonizer, Porphyromonas gingivalis has long been considered a key player in the initiation of periodontitis, suggesting the potential for novel narrow-spectrum therapeutics. By targeting key pathogens, it may be possible to treat periodontitis while allowing for the recolonization of the beneficial, healthy flora. Therefore, we set out to use P. gingivalis and periodontal disease as a model for pathogen-specific antimicrobial drug discovery. In this study we present a unique approach to predict essential gene targets selective for the periodontal pathogen within the oral environment. Using our knowledge of metabolic networks and essential genes we identified a “druggable” essential target, meso-diaminopimelate dehydrogenase, which is found in a limited number of species. This enzyme, meso-diaminopimelate dehydrogenase from P. gingivalis, was first expressed and purified, then characterized for enzymatic inhibitor screening studies. We then applied a computer-based drug discovery method, combining pharmacophore models, high-throughput virtual screening and molecular docking. Utilizing the ZINC database we virtually screened over 9 million small-molecules to identify several potential target-specific inhibitors. Finally, we used target-based and whole-cell based biochemical screening to assess in vitro activity. We conclude that the establishment of this target and screening strategy provides a framework for the future development of new antimicrobials and drug discovery.