Jenna M. Lang

and 2 more

ABSTRACT Far more attention has been paid to the microbes in our feces than the microbes in our food. Research efforts dedicated to the microbes that we eat have historically been focused on a fairly narrow range of species, namely those which cause disease and those which are thought to confer some "probiotic" health benefit. Little is known about the effects of ingested microbial communities that are present in typical American diets, and even the basic questions of which microbes, how many of them, and how much they vary from diet to diet and meal to meal, have not been answered. We characterized the microbiota of three different dietary patterns in order to estimate: the average total amount of daily microbes ingested via food and beverages, and their composition in three daily meal plans representing three different dietary patterns. The three dietary patterns analyzed were: 1) the Average American (AMERICAN): focused on convenience foods, 2) USDA recommended (USDA): emphasizing fruits and vegetables, lean meat, dairy, and whole grains, and 3) Vegan (VEGAN): excluding all animal products. Meals were prepared in a home kitchen or purchased at restaurants and blended, followed by microbial analysis including aerobic, anaerobic, yeast and mold plate counts as well as 16S rRNA PCR survey analysis. Based on plate counts, the USDA meal plan had the highest total amount of microbes at \(1.3 X 10^9\) CFU per day, followed by the VEGAN meal plan and the AMERICAN meal plan at \(6 X 10^6 \)and \(1.4 X 10^6\) CFU per day respectively. There was no significant difference in diversity among the three dietary patterns. Individual meals clustered based on taxonomic composition independent of dietary pattern. For example, meals that were abundant in Lactic Acid Bacteria were from all three dietary patterns. Some taxonomic groups were correlated with the nutritional content of the meals. Predictive metagenome analysis using PICRUSt indicated differences in some functional KEGG categories across the three dietary patterns and for meals clustered based on whether they were raw or cooked. Further studies are needed to determine the impact of ingested microbes on the intestinal microbiota, the extent of variation across foods, meals and diets, and the extent to which dietary microbes may impact human health. The answers to these questions will reveal whether dietary microbial approaches beyond probiotics taken as supplements - _i.e._, ingested as foods - are important contributors to the composition, inter-individual variation, and function of our gut microbiota.

Jenna M. Lang

and 8 more

ABSTRACT Background: Modern advances in sequencing technology have enabled the census of microbial members of many natural ecosystems. Recently, attention is increasingly being paid to the microbial residents of human-made, built ecosystems, both private (homes) and public (subways, office buildings, and hospitals). Here, we report results of the characterization of the microbial ecology of a singular built environment, the International Space Station (ISS). This ISS sampling involved the collection and microbial analysis (via 16S rDNA PCR) of 15 surfaces sampled by swabs onboard the ISS. This sampling was a component of Project MERCCURI (Microbial Ecology Research Combining Citizen and University Researchers on ISS). Learning more about the microbial inhabitants of the "buildings" in which we travel through space will take on increasing importance, as plans for human exploration and colonization of the solar system come to fruition. Results: Sterile swabs were used to sample 15 surfaces onboard the ISS. The sites sampled were designed to be analogous to samples collected for 1) the Wildlife of Our Homes project and 2) a study of cell phones and shoes that were concurrently being collected for another component of Project MERCCURI. Sequencing of the 16S rDNA genes amplified from DNA extracted from each swab was used to produce a census of the microbes present on each surface sampled. We compared the microbes found on the ISS swabs to those from both Earth homes and data from the Human Microbiome Project. Conclusions: While significantly different from homes on Earth and the Human Microbiome Project samples analyzed here, the microbial community composition on the ISS was more similar to home surfaces than to the human microbiome samples. The ISS surfaces are species-rich with 1036-4294 operational taxonomic units (OTUs per sample). There was no discernible biogeography of microbes on the 15 ISS surfaces, although this may be a reflection of the small sample size we were able to obtain.

Holly Bik

and 15 more

In recent years, microbial ecology studies have increasingly focused on the "Built Environment", characterizing community assemblages across indoor habitats such as classrooms, homes, and hospitals. Human activity and manipulation of indoor spaces can impact both the microbial taxa present and changes in communities over time. In this study, we sought to characterize the spatial and temporal patterns of microbes in two saltwater aquariums at UC Davis; the goal of this project was to provide a substantial research experience for undergraduate students while examining the microbiology of the built environment. Aquariums are a common feature of homes and buildings, yet little is known about how environmental perturbations (water changes, addition of living rocks) can impact the succession of microbial communities. We monitored microbial succession as two "coral pond" aquaria were being established. Water and sediment samples were collected over a 3-month period from November 2012 to January 2013, in parallel with water chemistry data at each timepoint. Samples were subjected to DNA extraction and environmental amplification of the 16S rRNA gene, followed by sequencing on the Illumina MiSeq platform. High-throughput sequence data was processed and analyzed using the QIIME pipeline. Our results showed similar patterns of microbial community succession in both saltwater aquariums, in regard to the profiles of abundant taxa and the timing of successional changes. Furthermore, we observed a significant difference in microbial assemblages in sediment versus water samples, indicating strong heterogeneity and partitioning of microbial habitats within aquariums.