Skin, gut, and sand metagenomic data on placebo-controlled sandbox biodiversity intervention study.

The metagenomic data presented in this article are related to the published research of "A Placebo-controlled double-blinded test of the biodiversity hypothesis of immune-mediated diseases: Environmental microbial diversity elicits changes in cytokines and increase in T regulatory cells in young children" This database contains 16S ribosomal RNA (rRNA) metagenomics of sandbox sand and skin and gut microbiota of children in the intervention and placebo daycares. In intervention daycares, children aged 3-5 years were exposed to playground sand enriched with microbially diverse soil. In placebo daycares, children were exposed to visually similar as in intervention daycares, but microbially poor sand colored with peat. Sand, skin and gut metagenomics were analyzed at baseline and after 14 and 28 days of intervention by high throughput sequencing of bacterial 16S rRNA gene on the Illumina MiSeq platform. This dataset shows how skin bacterial community composition, including classes Gammaproteobacteria and Bacilli, changed, and how the relative abundance of over 30 bacterial genera shifted on the skin of children in the intervention treatment, while no shifts occurred in the placebo group.

Coxsackievirus B infections are common in Cystic Fibrosis and experimental evidence supports protection by vaccination.

Viral respiratory tract infections exacerbate airway disease and facilitate life-threatening bacterial colonization in cystic fibrosis (CF). Annual influenza vaccination is recommended and vaccines against other common respiratory viruses may further reduce pulmonary morbidity risk. Enteroviruses have been found in nasopharyngeal samples from CF patients experiencing pulmonary exacerbations. Using serology tests, we found that infections by a group of enteroviruses, Coxsackievirus Bs (CVBs), are prevalent in CF. We next showed that a CVB vaccine, currently undergoing clinical development, prevents infection and CVB-instigated lung damage in a murine model of CF. Finally, we demonstrate that individuals with CF have normal vaccine responses to a similar, commonly used enterovirus vaccine (inactivated poliovirus vaccine). Our study demonstrates that CVB infections are common in CF and provides experimental evidence indicating that CVB vaccines could be efficacious in the CF population. The role of CVB infections in contributing to pulmonary exacerbations in CF should be further studied.

A Placebo-controlled double-blinded test of the biodiversity hypothesis of immune-mediated diseases: Environmental microbial diversity elicits changes in cytokines and increase in T regulatory cells in young children.

BACKGROUND: According to the biodiversity hypothesis of immune-mediated diseases, lack of microbiological diversity in the everyday living environment is a core reason for dysregulation of immune tolerance and - eventually - the epidemic of immune-mediated diseases in western urban populations. Despite years of intense research, the hypothesis was never tested in a double-blinded and placebo-controlled intervention trial. OBJECTIVE: We aimed to perform the first placebo-controlled double-blinded test that investigates the effect of biodiversity on immune tolerance. METHODS: In the intervention group, children aged 3-5 years were exposed to playground sand enriched with microbially diverse soil, or in the placebo group, visually similar, but microbially poor sand colored with peat (13 participants per treatment group). Children played twice a day for 20 min in the sandbox for 14 days. Sand, skin and gut bacterial, and blood samples were taken at baseline and after 14 days. Bacterial changes were followed for 28 days. Sand, skin and gut metagenome was determined by high throughput sequencing of bacterial 16 S rRNA gene. Cytokines were measured from plasma and the frequency of blood regulatory T cells was defined as a percentage of total CD3 +CD4 + T cells. RESULTS: Bacterial richness (P < 0.001) and diversity (P < 0.05) were higher in the intervention than placebo sand. Skin bacterial community, including Gammaproteobacteria, shifted only in the intervention treatment to resemble the bacterial community in the enriched sand (P < 0.01). Mean change in plasma interleukin-10 (IL-10) concentration and IL-10 to IL-17A ratio supported immunoregulation in the intervention treatment compared to the placebo treatment (P = 0.02). IL-10 levels (P = 0.001) and IL-10 to IL-17A ratio (P = 0.02) were associated with Gammaproteobacterial community on the skin. The change in Treg frequencies was associated with the relative abundance of skin Thermoactinomycetaceae 1 (P = 0.002) and unclassified Alphaproteobacteria (P < 0.001). After 28 days, skin bacterial community still differed in the intervention treatment compared to baseline (P < 0.02). CONCLUSIONS: This is the first double-blinded placebo-controlled study to show that daily exposure to microbial biodiversity is associated with immune modulation in humans. The findings support the biodiversity hypothesis of immune-mediated diseases. We conclude that environmental microbiota may contribute to child health, and that adding microbiological diversity to everyday living environment may support immunoregulation.

Effect of inactivated nature-derived microbial composition on mouse immune system.

INTRODUCTION: The hygiene hypothesis suggests that decrease in early life infections due to increased societal-level hygiene standards subjects one to allergic and autoimmune diseases. In this report, we have studied the effect of sterilized forest soil and plant-based material on mouse immune system and gut microbiome. METHODS: Inbred C57Bl/6 mice maintained in normal sterile environment were subjected to autoclaved forest soil-derived powder in their bedding for 1 h a day for 3 weeks. Immune response was measured by immune cell flow cytometry, serum cytokine enzyme-linked immunoassay (ELISA) and quantitative polymerase chain reaction (qPCR) analysis. Furthermore, the mouse gut microbiome was analyzed by sequencing. RESULTS: When compared to control mice, mice treated with soil-derived powder had decreased level of pro-inflammatory cytokines namely interleukin (IL)-17F and IL-21 in the serum. Furthermore, splenocytes from mice treated with soil-derived powder expressed less IL-1b, IL-5, IL-6, IL-13, and tumor necrosis factor (TNF) upon cell activation. Gut microbiome appeared to be stabilized by the treatment. CONCLUSIONS: These results provide insights on the effect of biodiversity on murine immune system in sterile environment. Subjecting mice to soil-based plant and microbe structures appears to elicit immune response that could be beneficial, for example, in type 2 inflammation-related diseases, that is, allergic diseases.

Land Cover of Early-Life Environment Modulates the Risk of Type 1 Diabetes.

OBJECTIVE: Environmental microbial exposures have been implicated to protect against immune-mediated diseases such as type 1 diabetes. Our objective was to study the association of land cover around the early-life dwelling with the development of islet autoimmunity and type 1 diabetes to evaluate the role of environmental microbial biodiversity in the pathogenesis. RESEARCH DESIGN AND METHODS: Association between land cover types and the future risk of type 1 diabetes was studied by analyzing land cover types classified according to Coordination of Information on the Environment (CORINE) 2012 and 2000 data around the dwelling during the first year of life for 10,681 children genotyped for disease-associated HLA-DQ alleles and monitored from birth in the Type 1 Diabetes Prediction and Prevention (DIPP) study. Land cover was compared between children who developed type 1 diabetes (n = 271) or multiple diabetes-associated islet autoantibodies (n = 384) and children without diabetes who are negative for diabetes autoantibodies. RESULTS: Agricultural land cover around the home was inversely associated with diabetes risk (odds ratio 0.37, 95% CI 0.16-0.87, P = 0.02 within a distance of 1,500 m). The association was observed among children with the high-risk HLA genotype and among those living in the southernmost study region. Snow cover on the ground seemed to block the transfer of the microbial community indoors, leading to reduced bacterial richness and diversity indoors, which might explain the regional difference in the association. In survival models, an agricultural environment was associated with a decreased risk of multiple islet autoantibodies (hazard ratio [HR] 1.60, P = 0.008) and a decreased risk of progression from single to multiple autoantibody positivity (HR 2.07, P = 0.001) compared with an urban environment known to have lower environmental microbial diversity. CONCLUSIONS: The study suggests that exposure to an agricultural environment (comprising nonirrigated arable land, fruit trees and berry plantations, pastures, natural pastures, land principally occupied by agriculture with significant areas of natural vegetation, and agroforestry areas) early in life is inversely associated with the risk of type 1 diabetes. This association may be mediated by early exposure to environmental microbial diversity.

Do Rural Second Homes Shape Commensal Microbiota of Urban Dwellers? A Pilot Study among Urban Elderly in Finland.

According to the hygiene and biodiversity hypotheses, increased hygiene levels and reduced contact with biodiversity can partially explain the high prevalence of immune-mediated diseases in developed countries. A disturbed commensal microbiota, especially in the gut, has been linked to multiple immune-mediated diseases. Previous studies imply that gut microbiota composition is associated with the everyday living environment and can be modified by increasing direct physical exposure to biodiverse materials. In this pilot study, the effects of rural-second-home tourism were investigated on the gut microbiota for the first time. Rural-second-home tourism, a popular form of outdoor recreation in Northern Europe, North America, and Russia, has the potential to alter the human microbiota by increasing exposure to nature and environmental microbes. The hypotheses were that the use of rural second homes is associated with differences in the gut microbiota and that the microbiota related to health benefits are more diverse or common among the rural-second-home users. Based on 16S rRNA Illumina MiSeq sequencing of stool samples from 10 urban elderly having access and 15 lacking access to a rural second home, the first hypothesis was supported: the use of rural second homes was found to be associated with lower gut microbiota diversity and RIG-I-like receptor signaling pathway levels. The second hypothesis was not supported: health-related microbiota were not more diverse or common among the second-home users. The current study encourages further research on the possible health outcomes or causes of the observed microbiological differences. Activities and diet during second-home visits, standard of equipment, surrounding environment, and length of the visits are all postulated to play a role in determining the effects of rural-second-home tourism on the gut microbiota.

Associations between land cover categories, gaseous PAH levels in ambient air and endocrine signaling predicted from gut bacterial metagenome of the elderly.

There is evidence that polycyclic aromatic hydrocarbons (PAHs) and human gut microbiota are associated with the modulation of endocrine signaling pathways. Independently, studies have found associations between air pollution, land cover and commensal microbiota. We are the first to estimate the interaction between land cover categories associated with air pollution or purification, PAH levels and endocrine signaling predicted from gut metagenome among urban and rural populations. The study participants were elderly people (65-79 years); 30 lived in rural and 32 in urban areas. Semi-Permeable Membrane devices were utilized to measure air PAH concentrations as they simulate the process of bioconcentration in the fatty tissues. Land cover categories were estimated using CORINE database and geographic information system. Functional orthologues for peroxisome proliferator-activated receptor (PPAR) pathway in endocrine system were analyzed from gut bacterial metagenome with Kyoto Encyclopaedia of Genes and Genomes. High coverage of broad-leaved and mixed forests around the homes were associated with decreased PAH levels in ambient air, while gut functional orthologues for PPAR pathway increased along with these forest types. The difference between urban and rural PAH concentrations was not notable. However, some rural measurements were higher than the urban average, which was due to the use of heavy equipment on active farms. The provision of air purification by forests might be an important determining factor in the context of endocrine disruption potential of PAHs. Particularly broad-leaved forests around homes may reduce PAH levels in ambient air and balance pollution-induced disturbances within commensal gut microbiota.

Biodiversity intervention enhances immune regulation and health-associated commensal microbiota among daycare children.

As the incidence of immune-mediated diseases has increased rapidly in developed societies, there is an unmet need for novel prophylactic practices to fight against these maladies. This study is the first human intervention trial in which urban environmental biodiversity was manipulated to examine its effects on the commensal microbiome and immunoregulation in children. We analyzed changes in the skin and gut microbiota and blood immune markers of children during a 28-day biodiversity intervention. Children in standard urban and nature-oriented daycare centers were analyzed for comparison. The intervention diversified both the environmental and skin Gammaproteobacterial communities, which, in turn, were associated with increases in plasma TGF-ß1 levels and the proportion of regulatory T cells. The plasma IL-10:IL-17A ratio increased among intervention children during the trial. Our findings suggest that biodiversity intervention enhances immunoregulatory pathways and provide an incentive for future prophylactic approaches to reduce the risk of immune-mediated diseases in urban societies.

Yard vegetation is associated with gut microbiota composition.

Gut microbes play an essential role in the development and functioning of the human immune system. A disturbed gut microbiota composition is often associated with a number of health disorders including immune-mediated diseases. Differences in host characteristics such as ethnicity, living habit and diet have been used to explain differences in the gut microbiota composition in inter-continental comparison studies. As our previous studies imply that daily skin contact with organic gardening materials modify gut microflora, here we investigated the association between living environment and gut microbiota in a homogenous western population along an urban-rural gradient. We obtained stool samples from 48 native elderly Finns in province Häme in August and November 2015 and identified the bacterial phylotypes using 16S rRNA Illumina MiSeq sequencing. We assumed that yard vegetation and land cover classes surrounding homes explain the stool bacterial community in generalized linear mixed models. Diverse yard vegetation was associated with a reduced abundance of Clostridium sensu stricto and an increased abundance of Faecalibacterium and Prevotellaceae. The abundance of Bacteroides was positively and strongly associated with the built environment. Exclusion of animal owners did not alter the main associations. These results suggest that diverse vegetation around homes is associated with health-related changes in gut microbiota composition. Manipulation of the garden diversity, possibly jointly with urban planning, is a promising candidate for future intervention studies that aim to maintain gut homeostasis.

Temporal variation in indoor transfer of dirt-associated environmental bacteria in agricultural and urban areas.

An agricultural environment and exposure to diverse environmental microbiota has been suggested to confer protection against immune-mediated disorders. As an agricultural environment may have a protective role, it is crucial to determine whether the limiting factors in the transfer of environmental microbiota indoors are the same in the agricultural and urban environments. We explored how sampling month, garden diversity and animal ownership affected the indoor-transfer of environmental microbial community. We collected litter from standardized doormats used for 2 weeks in June and August 2015 and February 2016 and identified bacterial phylotypes using 16S rRNA Illumina MiSeq sequencing. In February, the diversity and richness of the whole bacterial community and the relative abundance of environment-associated taxa were reduced, whereas human-associated taxa and genera containing opportunistic pathogens were enriched in the doormats. In summer, the relative abundances of several taxa associated previously with beneficial health effects were higher, particularly in agricultural areas. Surprisingly, the importance of vegetation on doormat microbiota was more observable in February, which may have resulted from snow cover that prevented contact with microbes in soil. Animal ownership increased the prevalence of genera Bacteroides and Acinetobacter in rural doormats. These findings underline the roles of season, living environment and lifestyle in the temporal variations in the environmental microbial community carried indoors. As reduced contact with diverse microbiota is a potential reason for immune system dysfunction, the results may have important implications in the etiology of immune-mediated, non-communicable diseases.

Endocrine disruption and commensal bacteria alteration associated with gaseous and soil PAH contamination among daycare children.

Polycyclic aromatic hydrocarbons (PAHs) are priority environmental pollutants that cause adverse health effects. PAHs belong to endocrine signaling disruptors to which children are sensitive to. Recent evidence suggests that PAH pollution alters the abundance of environmental bacteria that is associated with health outcomes. The alteration of environmental and commensal microbiota by PAH pollution has never been connected to endocrine signaling pathways. To estimate the risk of endocrine disruption in daycare children, we measured PAHs from soil and air of eleven urban daycare centres in Finland. We analyzed daycare yards' soil and children's gut and skin bacterial communities with 16S rRNA gene metabarcoding and used Kyoto Encyclopaedia of Genes and Genomes database to categorize endocrine signaling pathways. We also assessed the PAH hazard to children's health based on the current risk assesments. We observed associations between signaling pathways in endocrine system and gaseous PAH levels in ambient air. Peroxisome proliferator-activated receptor and adipocytokine signaling pathway decreased with higher chrysene concentration in the air. Soil PAH contamination was associated with altered Actinobacteria, Bacteoridetes and Proteobacteria communities on children's skin and in daycare yard soil. However, adjusted genera were not the same in soil and on skin, with the exception of Mycobacterium that was associated with higher PAH concentrations both in soil and on the skin. Even though fluoranhtene levels were above the current threshold values, total PAHs were below safety threshold values and based on current risk assessments there is a minor risk for child health. Our findings indicate that PAH concentrations that are considered safe may interfere with endocrine signaling by commensal microbiota and alter both environmental and commensal bacterial communities. The imbalance in human microbiota and the decrease in signaling pathways may contribute to emerging public health problems, including inflammatory disorders, obesity and diabetes. Therefore, the optimal risk assessments of PAHs and theoretically also other contaminants shaping commensal microbiota may need to take into account the possibility of the disruption of endocrine signaling pathways.

Diverse Environmental Microbiota as a Tool to Augment Biodiversity in Urban Landscaping Materials.

Human activities typically lead to simplified urban diversity, which in turn reduces microbial exposure and increases the risk to urban dwellers from non-communicable diseases. To overcome this, we developed a microbial inoculant from forest and agricultural materials that resembles microbiota in organic soils. Three different sand materials (sieved, safety, and sandbox) commonly used in playgrounds and other public spaces were enriched with 5% of the inoculant. Skin microbiota on fingers (identified from bacterial 16S rDNA determined using Illumina MiSeq sequencing) was compared after touching non-enriched and microbial inoculant-enriched sands. Exposure to the non-enriched materials changed the skin bacterial community composition in distinct ways. When the inoculant was added to the materials, the overall shift in community composition was larger and the differences between different sand materials almost disappeared. Inoculant-enriched sand materials increased bacterial diversity and richness but did not affect evenness at the OTU level on skin. The Firmicutes/Bacteroidetes ratio was higher after touching inoculant-enriched compared to non-enriched sand materials. The relative abundance of opportunistic pathogens on skin was 40-50% before touching sand materials, but dropped to 14 and 4% after touching standard and inoculant-enriched sand materials, respectively. When individual genera were analyzed, Pseudomonas sp. and Sphingomonas sp. were more abundant after touching standard, non-enriched sand materials, while only the relative abundance of Chryseobacterium sp. increased after touching the inoculant-enriched materials. As Chryseobacterium is harmless for healthy persons, and as standard landscaping materials and normal skin contain genera that include severe pathogens, the inoculant-enriched materials can be considered safe. Microbial inoculants could be specifically created to increase the proportion of non-pathogenic bacterial taxa and minimize the transfer of pathogenic taxa. We recommend further study into the usability of inoculant-enriched materials and their effects on the bacterial community composition of human skin and on the immune response.

Short-term direct contact with soil and plant materials leads to an immediate increase in diversity of skin microbiota.

Immune-mediated diseases have increased during the last decades in urban environments. The hygiene hypothesis suggests that increased hygiene level and reduced contacts with natural biodiversity are related to the increase in immune-mediated diseases. We tested whether short-time contact with microbiologically diverse nature-based materials immediately change bacterial diversity on human skin. We tested direct skin contact, as two volunteers rubbed their hands with sixteen soil and plant based materials, and an exposure via fabric packets filled with moss material. Skin swabs were taken before and after both exposures. Next-generation sequencing showed that exposures increased, at least temporarily, the total diversity of skin microbiota and the diversity of Acidobacteria, Actinobacteria, Bacteroidetes, Proteobacteria and Alpha-, Beta- and Gammaproteobacteria suggesting that contact with nature-based materials modify skin microbiome and increase skin microbial diversity. Until now, approaches to cure or prevent immune system disorders using microbe-based treatments have been limited to use of a few microbial species. We propose that nature-based materials with high natural diversity, such as the materials tested here, might be more effective in modifying human skin microbiome, and eventually, in reducing immune system disorders. Future studies should investigate how long-term changes in skin microbiota are achieved and if the exposure induces beneficial changes in the immune system markers.

N-Prenylation of Tryptophan by an Aromatic Prenyltransferase from the Cyanobactin Biosynthetic Pathway.

Aromatic prenylation is an important step in the biosynthesis of many natural products and leads to an astonishing diversity of chemical structures. Cyanobactin pathways frequently encode aromatic prenyltransferases that catalyze the prenylation of these macrocyclic and linear peptides. Here we characterized the anacyclamide ( acy) biosynthetic gene cluster from Anabaena sp. UHCC-0232. Partial reconstitution of the anacyclamide pathway, heterologous expression, and in vitro biochemical characterization demonstrate that the AcyF enzyme, encoded in the acy biosynthetic gene cluster, is a Trp N-prenyltransferase. Bioinformatic analysis suggests the monophyletic origin and rapid diversification of cyanobactin prenyltransferase enzymes and the multiple origins of N-1 Trp prenylation in prenylated natural products. The AcyF enzyme displayed high flexibility toward a range of Trp-containing substrates and represents an interesting new tool for biocatalytic applications.

Nature-derived microbiota exposure as a novel immunomodulatory approach.

AIM: Current attempts to modulate the human microbiota and immune responses are based on probiotics or human-derived bacterial transplants. We investigated microbial modulation by soil and plant-based material. MATERIALS & METHODS: We performed a pilot study in which healthy adults were exposed to the varied microbial community of a soil- and plant-based material. RESULTS: The method was safe and feasible; exposure was associated with an increase in gut microbial diversity. CONCLUSION: If these findings are reproduced in larger studies nature-derived microbial exposure strategies could be further developed for testing their efficacy in the treatment and prevention of immune-mediated diseases.

Half-lives of PAHs and temporal microbiota changes in commonly used urban landscaping materials.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) accumulate in urban soils, and PAH contamination can change soil microbial community composition. Environmental microbiota is associated with human commensal microbiota, immune system and health. Therefore, studies investigating the degradation of PAHs, and the consequences of soil pollution on microbial communities in urban landscaping materials, are crucial. METHODS: Four landscaping materials (organic matter 1, 2, 13 and 56%) were contaminated with PAHs commonly found at urban sites (phenanthrene, fluoranthene, pyrene, chrysene and benzo(b)fluoranthene) in PAH concentrations that reflect urban soils in Finland (2.4 µg g -1 soil dry weight). PAHs were analyzed initially and after 2, 4, 8 and 12 weeks by gas chromatography-mass spectrometry. Half-lives of PAHs were determined based on 12-weeks degradation. Bacterial communities were analyzed at 1 and 12 weeks after contamination using Illumina MiSeq 16S rRNA gene metabarcoding. RESULTS: Half-lives ranged from 1.5 to 4.4 weeks for PAHs with relatively low molecular weights (phenanthrene, fluoranthene and pyrene) in landscaping materials containing 1-2% organic matter. In contrast, in materials containing 13% and 56% organic matter, the half-lives ranged from 2.5 to 52 weeks. Shorter half-lives of phenanthrene and fluoranthene were thus associated with low organic matter content. The half-life of pyrene was inversely related to the relative abundance of Beta-, Delta- and Gammaproteobacteria, and diversity of Bacteroidetes and Betaprotebacteria. Compounds with higher molecular weights followed compound-specific patterns. Benzo(b)fluoranthene was resistant to degradation and half-life of chrysene was shorter when the relative abundance of Betaproteobacteria was high. Temporal microbiota changes involved increase in the relative abundance of Deltaproteobacteria and decrease in genera Flavobacterium and Rhodanobacter. Exposure to PAHs seems to adjust microbial community composition, particularly within class Beta- and Deltaproteobacteria. CONCLUSIONS: In this study, PAH degradation depended on the organic matter content and bacterial community composition of landscaping materials. Contamination seems to alter bacterial community composition in landscaping materials depending on material type. This alteration includes changes in bacterial phyla associated with human health and immune system. This may open new possibilities for managing urban environments by careful selection of landscaping materials, to benefit health and wellbeing.

Urbanization Reduces Transfer of Diverse Environmental Microbiota Indoors.

Expanding urbanization is a major factor behind rapidly declining biodiversity. It has been proposed that in urbanized societies, the rarity of contact with diverse environmental microbiota negatively impacts immune function and ultimately increases the risk for allergies and other immune-mediated disorders. Surprisingly, the basic assumption that urbanization reduces exposure to environmental microbiota and its transfer indoors has rarely been examined. We investigated if the land use type around Finnish homes affects the diversity, richness, and abundance of bacterial communities indoors. Debris deposited on standardized doormats was collected in 30 rural and 26 urban households in and near the city of Lahti, Finland, in August 2015. Debris was weighed, bacterial community composition determined by high throughput sequencing of bacterial 16S ribosomal RNA (rRNA) gene on the Illumina MiSeq platform, and the percentage of four different land use types (i.e., built area, forest, transitional, and open area) within 200 m and 2000 m radiuses from each household was characterized. The quantity of doormat debris was inversely correlated with coverage of built area. The diversity of total bacterial, Proteobacterial, Actinobacterial, Bacteroidetes, and Firmicutes communities decreased as the percentage of built area increased. Their richness followed the same pattern except for Firmicutes for which no association was observed. The relative abundance of Proteobacteria and particularly Gammaproteobacteria increased, whereas that of Actinobacteria decreased with increasing built area. Neither Phylum Firmicutes nor Bacteroidetes varied with coverage of built area. Additionally, the relative abundance of potentially pathogenic bacterial families and genera increased as the percentage of built area increased. Interestingly, having domestic animals (including pets) only altered the association between the richness of Gammaproteobacteria and diversity of Firmicutes with the built area coverage suggesting that animal ownership minimally affects transfer of environmental microbiota indoors from the living environment. These results support the hypothesis that people living in densely built areas are less exposed to diverse environmental microbiota than people living in more sparsely built areas.

The abundance of health-associated bacteria is altered in PAH polluted soils-Implications for health in urban areas?

Long-term exposure to polyaromatic hydrocarbons (PAHs) has been connected to chronic human health disorders. It is also well-known that i) PAH contamination alters soil bacterial communities, ii) human microbiome is associated with environmental microbiome, and iii) alteration in the abundance of members in several bacterial phyla is associated with adverse or beneficial human health effects. We hypothesized that soil pollution by PAHs altered soil bacterial communities that had known associations with human health. The rationale behind our study was to increase understanding and potentially facilitate reconsidering factors that lead to health disorders in areas characterized by PAH contamination. Large containers filled with either spruce forest soil, pine forest soil, peat, or glacial sand were left to incubate or contaminated with creosote. Biological degradation of PAHs was monitored using GC-MS, and the bacterial community composition was analyzed using 454 pyrosequencing. Proteobacteria had higher and Actinobacteria and Bacteroidetes had lower relative abundance in creosote contaminated soils than in non-contaminated soils. Earlier studies have demonstrated that an increase in the abundance of Proteobacteria and decreased abundance of the phyla Actinobacteria and Bacteroidetes are particularly associated with adverse health outcomes and immunological disorders. Therefore, we propose that pollution-induced shifts in natural soil bacterial community, like in PAH-polluted areas, can contribute to the prevalence of chronic diseases. We encourage studies that simultaneously address the classic "adverse toxin effect" paradigm and our novel "altered environmental microbiome" hypothesis.

A Unique Tryptophan C-Prenyltransferase from the Kawaguchipeptin Biosynthetic Pathway.

Cyanobactins are a rapidly growing family of linear and cyclic peptides produced by cyanobacteria. Kawaguchipeptins A and B, two macrocyclic undecapeptides reported earlier from Microcystis aeruginosa NIES-88, are shown to be products of the cyanobactin biosynthetic pathway. The 9 kb kawaguchipeptin (kgp) gene cluster was identified in a 5.26 Mb draft genome of Microcystis aeruginosa NIES-88. We verified that this gene cluster is responsible for the production of the kawaguchipeptins through heterologous expression of the kgp gene cluster in Escherichia coli. The KgpF prenyltransferase was overexpressed and was shown to prenylate C-3 of Trp residues in both linear and cyclic peptides in vitro. Our findings serve to further enhance the structural diversity of cyanobactins to include tryptophan-prenylated cyclic peptides.