Defense Date
2024
Document Type
Directed Research Project
First Advisor
Baneshwar Singh
Second Advisor
Tal Simmons
Third Advisor
Jenise Swall
Abstract
In 1994, during the construction of the Kontos Building on the Medical College of Virginia Campus, a well on East Marshall Street was discovered to contain artifacts and human remains of African descent. Upon archaeological analysis by the Smithsonian, the ancestral remains can be dated back to the mid-19th century, when grave robbing and the use of cadavers for anatomical purposes [BS1] in medical schools were common. The human oral microbiome is the second largest human microbiota, containing over 600 species of organisms. Dysbiosis of the oral microbiome can lead to the overgrowth of pathogenic species, resulting in illness and disease. Dental calculus is an abundant source of the human oral microbiome, providing insight into an individual's health and diet. The mineralized biofilm that makes up dental calculus traps a variety of particles, including bacteria, viruses, and food remnants. The aims of this project are to use dental calculus (n=18) recovered from the mandible and maxilla to gain insight into the ancestral remains health environment, compare modern (n=28) and 19th century dental calculus (n=18) to determine differences in the oral microflora over the past few centuries, determine the extent of environmental contamination through soil (n=9) collected from the cranial vault, and compare the effects of decontamination and decalcification on microbiome of 19th century dental calculus [cleaned (n=12) and uncleaned (n=6)]. This was done through [BS2] 16S rDNA (V4 region) dual-index amplification and next-generation sequencing using the MiSeq FGx platform. The data was analyzed on mothur v1.48.0 and statistical calculations were conducted on Excel and SPSS. The taxonomy profiles revealed the presence of pathogenic bacteria that can be attributed to disease and major differences between the dental calculus of the East Marshall Street Well Individuals and modern dental calculus. Most notably, the bacteria known to cause Tetanus (Clostridium tetani), and Syphilis (family: Spirochaetaceae) was found in a very high abundance in three bones recovered from the East Marshall Street Well (EMSW). Additionally, bacteria known to be associated with various oral diseases and Tuberculosis (Mycobacterium tuberculosis) were found within the EMSW dental calculus. The top three bacterial genera associated with the modern dental calculus samples are Fusobacterium (31.56%), Prevotella (26.07%), [BS3] and Selenomonas (14.35%). Furthermore, the top three bacterial genera associated with the uncleaned EMSW [BS4] dental calculus are an unclassified bacteria (23.85%), unclassified Cytophagales (11.15%), and Syntrophomonas (11.15%). Last, the top three bacterial genera associated with the cleaned EMSW dental calculus samples are an unclassified bacterium (31.70%), SHD-231 (22.68%), and unclassified clostridia (9.93%). The Analysis of Molecular Variance (AMOVA) indicated a significant difference in bacterial structures between modern and old calculus and between cleaned and uncleaned old calculus samples (p-valueth century, the impact of environmental contamination, and allowed the further recognition of the lives and history of those individuals recovered from the EMSW.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
4-30-2024