Normal pregnancy represents a unique, transient, and dynamic state of altered anatomy, physiology, and immune function. Preterm birth, i.e., before 37 weeks of gestation, occurs in approximately 11% of pregnancies and is the leading cause of neonatal death. In both term and preterm pregnancies, the interplay between the microbiota and the host remains poorly understood. The human indigenous microbial communities (microbiota) play critical roles in health and may be especially important for mother and fetus during pregnancy. We are interested in understanding how the microbiome helps to shape maternal health and fetal development during pregnancy, and how pregnancy shapes the microbiome.

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Landscape ecology examines the relationships between the spatial arrangement of different landforms and the processes that give rise to spatial and temporal patterns in local community structure. The spatial ecology of the microbial communities that inhabit the human body—and in particular, those of the mouth—deserve greater attention. Important questions include what defines the size of a population (i.e., ‘‘patch’’) in a given body site, what defines the boundaries of distinct patches within a single body site, what are the factors that explain boundaries, population composition, and patterns across populations, and where and over what spatial scales within a body site are gradients detected.

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Arsenic (As) contamination of soils and water occurs worldwide-including in the U.S.-originating from both environmental and anthropogenic sources. Naturally-occurring alluvial As contaminates groundwater in South and Southeast Asia, and has caused wide-scale poisoning of a susceptible and malnourished populace. Chronic As exposure affects over 25 million people in Bangladesh alone. Industrial sources of arsenic-e.g., arsenic-containing pesticides in agriculture-also contribute to global exposure. In the United States, As tops the hazardous substance priority list of the Agency for Toxic Substances and Disease Registries, and 13 million Americans are exposed to levels exceeding the US Water Quality Standards.

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This study will examine changes to the composition of the microbiome that occur in response to eating or avoiding dairy products, and the time course of such changes. We hypothesize that certain bacterial species in the gut microbiome are associated with acquired lactose tolerance: they allow hosts to eat dairy products without suffering the negative outcomes characteristic of lactose intolerance. We further hypothesize that regularly eating dairy products is necessary for the persistence of a lactose tolerance in most individuals, with dairy acting as a prebiotic to support the populations of lactose-utilizing, tolerance-associated bacteria. If these hypotheses are correct, our study may support informed consumption of dairy products in lactose intolerant individuals; it would allow them to develop and maintain lactose tolerance and to reap the potential health benefits of dairy, e.g. those related to the uptake of calcium.

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