Title: Mucor nidicola sp. nov., a novel fungal species isolated from an invasive paper wasp nest.... more Title: Mucor nidicola sp. nov., a novel fungal species isolated from an invasive paper wasp nest. 1 Authors: A. A. Madden, A. M. Stchigel, J. Guarro, D. Sutton, P. T. Starks 2 Author Affiliations: 3 1 Department of Biology, Tufts University, 120 Dana Laboratories, 163 Packard Avenue, 4 Medford, Massachusetts, USA. 02155. 5 Unitat de Microbiologia, Facultat de Medicina i Ciencies de la Salut, IISPV, Universitat Rovira 6 i Virgili, Sant Llorenç 21, 43201-Reus, Spain 7 Department of Pathology, The University of Texas Health Science Center, San Antonio, Texas, 8 USA 78229-3900. 9 Corresponding Author: 10 A. A. Madden 11 Email: [email protected] 12 Phone: 617-627-4294 Fax: 617-627-3805 13 Running Title: Mucor nidicola sp. nov. isolated from a paper wasp nest 14 Subject Category: New Taxa 15 Subsection: Eukaryotic Micro-organisms. 16 *The GenBank accession numbers for the ITS1-5.8rDNA-ITS2 sequences of the Mucor spp. 17 strains examined in this study are provided in a supplementary ta...
ronment, National Science Foundation Research Experience for Undergraduates, and Tufts Graduate S... more ronment, National Science Foundation Research Experience for Undergraduates, and Tufts Graduate School of Arts, Sciences & Engineering. Field and Lab work assistance from Jon Soriano, Andrew Grassetti, and Kelly Nguyen. Photo credits: A.A.M. Results: My results are currently being prepared for publications in peer-reviewed journals. Copies of these publications will be made available at the office of Tufts Institute of the Environment. Summary: Polistes dominulus is a species of paper wasp which has recently invaded North America, where it is increasing its range with climate change and development. While many insects are known to transfer microbes from their nests to plants they visit, acting as microbial vectors, there have been no molecular assessments evaluating the microbes which inhabit the nest of P. dominulus and which may have been transferred along with their invasion. By culturing the microbes from P. dominulus nests throughout Massachusetts and using the natives species ...
Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet ... more Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet of alkaloid-containing arthropods. Geographic and temporal variation in alkaloid defense is common in poison frogs, and is generally attributed to differences in the availability of alkaloid-containing arthropods. Variable chemical defense in poison frogs may have important consequences for predator-prey interactions, requiring a full understanding of the factors involved in explaining such variation. In the present study, we examine alkaloid variation in the dendrobatid poison frog Oophaga pumilio between males and females on Cayo Nancy (Isla Solarte), located in the Bocas del Toro archipelago of Panama. On average, females contained a significantly larger number and quantity of alkaloids when compared to males. Alkaloid composition varied significantly between males and females, illustrating that chemical defense in this population of O. pumilio is sex-dependent. The variation in alkal...
Sugar‐seeking insects as a source of diverse bread‐making yeasts with enhanced attributes
Yeast
Insects represent a particularly interesting habitat in which to search for novel yeasts of value... more Insects represent a particularly interesting habitat in which to search for novel yeasts of value to industry. Insect-associated yeasts have the potential to have traits relevant to modern food and beverage production due to insect-yeast interactions, with such traits including diverse carbohydrate metabolisms, high sugar tolerance, and general stress tolerance. Here, we consider the potential value of insect-associated yeasts in the specific context of baking. We isolated 63 yeast strains from 13 species of hymenoptera from the United States, representing 37 yeast species from 14 genera. Screening for the ability to ferment maltose, a sugar important for bread production, resulted in the identification of 13 strains of Candida, Lachancea, and Pichia species. We assessed their ability to leaven dough. All strains produced baked loaves comparable to a commercial baking strain of Saccharomyces cerevisiae. The same thirteen strains were also grown under various sugar and salt conditions relevant to osmotic challenges experienced in the manufacturing processes and the production of sweet dough. We show that many of these yeast strains, most notably strains of Lachancea species, grow at a similar or higher rate and population size as commercial baker's yeast. We additionally assessed the comparative phenotypes and genetics of insect-associated S. cerevisiae strains unable to ferment maltose and identified baking-relevant traits, including variations in the HOG1 signaling pathway and diverse carbohydrate metabolisms. Our results suggest that non-conventional yeasts have high potential for baking, and more generally, showcase the success of bioprospecting in insects for identifying yeasts relevant for industrial uses.
The practice of sourdough bread-making is an ancient science that involves the development, maint... more The practice of sourdough bread-making is an ancient science that involves the development, maintenance, and use of a diverse and complex starter culture. The sourdough starter culture comes in many different forms and is used in bread-making at both artisanal and commercial scales, in countries all over the world. While there is ample scientific research related to sourdough, there is no standardized approach to using sourdough starters in science or the bread industry; and there are few recommendations on future directions for sourdough research. Our review highlights what is currently known about the microbial ecosystem of sourdough (including microbial succession within the starter culture), methods of maintaining sourdough (analogous to land management) on the path to bread production, and factors that influence the sensory qualities of the final baked product. We present new hypotheses for the successful management of sourdough starters and propose future directions for sourdo...
History and Domestication of Saccharomyces cerevisiae in Bread Baking
Frontiers in Genetics
The yeast Saccharomyces cerevisiae has been instrumental in the fermentation of foods and beverag... more The yeast Saccharomyces cerevisiae has been instrumental in the fermentation of foods and beverages for millennia. In addition to fermentations like wine, beer, cider, sake, and bread, S. cerevisiae has been isolated from environments ranging from soil and trees, to human clinical isolates. Each of these environments has unique selection pressures that S. cerevisiae must adapt to. Bread dough, for example, requires S. cerevisiae to efficiently utilize the complex sugar maltose; tolerate osmotic stress due to the semi-solid state of dough, high salt, and high sugar content of some doughs; withstand various processing conditions, including freezing and drying; and produce desirable aromas and flavors. In this review, we explore the history of bread that gave rise to modern commercial baking yeast, and the genetic and genomic changes that accompanied this. We illustrate the genetic and phenotypic variation that has been documented in baking strains and wild strains, and how this variation might be used for baking strain improvement. While we continue to improve our understanding of how baking strains have adapted to bread dough, we conclude by highlighting some of the remaining open questions in the field.
Humans have relied on sourdough starter microbial communities to make leavened bread for thousand... more Humans have relied on sourdough starter microbial communities to make leavened bread for thousands of years, but only a small fraction of global sourdough biodiversity has been characterized. Working with a community-scientist network of bread bakers, we determined the microbial diversity of 500 sourdough starters from four continents. In sharp contrast with widespread assumptions, we found little evidence for biogeographic patterns in starter communities. Strong co-occurrence patterns observed in situ and recreated in vitro demonstrate that microbial interactions shape sourdough community structure. Variation in dough rise rates and aromas were largely explained by acetic acid bacteria, a mostly overlooked group of sourdough microbes. Our study reveals the extent of microbial diversity in an ancient fermented food across diverse cultural and geographic backgrounds.
Sourdough starters are naturally occurring microbial communities in which the environment, ingred... more Sourdough starters are naturally occurring microbial communities in which the environment, ingredients, and bakers are potential sources of microorganisms. The relative importance of these pools remains unknown. Here, bakers from two continents used a standardized recipe and ingredients to make starters that were then baked into breads. We characterized the fungi and bacteria associated with the starters, bakers’ hands, and ingredients using 16S and internal transcribed spacer (ITS) rRNA gene amplicon sequencing and then measured dough acidity and bread flavor. Starter communities were much less uniform than expected, and this variation manifested in the flavor of the bread. Starter communities were most similar to those found in flour but shared some species with the bakers’ skin. While humans likely contribute microorganisms to the starters, the reverse also appears to be true. This bidirectional exchange of microorganisms between starters and bakers highlights the importance of m...
Many species of yeast are integral to human society. They produce many of our foods, beverages an... more Many species of yeast are integral to human society. They produce many of our foods, beverages and industrial chemicals, challenge us as pathogens, and provide models for the study of our own biology. However, few species are regularly studied and much of their ecology remains unclear, hindering the development of knowledge that is needed to improve the relationships between humans and yeasts. There is increasing evidence that insects are an essential component of ascomycetous yeast ecology. We propose a 'dispersal-encounter hypothesis' whereby yeasts are dispersed by insects between ephemeral, spatially disparate sugar resources, and insects, in turn, obtain the benefits of an honest signal from yeasts for the sugar resources. We review the relationship between yeasts and insects through three main examples: social wasps, social bees and beetles, with some additional examples from fruit flies. Ultimately, we suggest that over the next decades, consideration of these ecologi...
Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in... more Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, social wasps are abundant in vineyards where they feed on ripe berries and cause significant damage, while also dispersing yeasts involved in wine fermentation. Despite this, their possible role in disease facilitation and dispersal of grape rots has not been explored. We tested the hypothesis that the paper wasp Polistes dominulus could facilitate grape sour rot...
We spend most of our lives inside homes, surrounded by arthropods that impact our property as pes... more We spend most of our lives inside homes, surrounded by arthropods that impact our property as pests and our health as disease vectors and producers of sensitizing allergens. Despite their relevance to human health and well-being, we know relatively little about the arthropods that exist in our homes and the factors structuring their diversity. As previous work has been limited in scale by the costs and time associated with collecting arthropods and the subsequent morphological identification, we used a DNA-based method for investigating the arthropod diversity in homes via high-throughput marker gene sequencing of home dust. Settled dust samples were collected by citizen scientists from both inside and outside more than 700 homes across the United States, yielding the first continental-scale estimates of arthropod diversity associated with our residences. We were able to document food webs and previously unknown geographic distributions of diverse arthropods - from allergen producer...
Our planet is changing rapidly, and responding to the ensuing environmental challenges will requi... more Our planet is changing rapidly, and responding to the ensuing environmental challenges will require an informed citizenry that can understand the inherent complexity of ecological systems. However, microorganisms are usually neglected in the narratives that we use to understand nature. Here, we advocate for the inclusion of microbial ecology across education levels and delineate the often neglected benefits of incorporating microbes into ecology curricula. We provide examples across education levels, from secondary school (by considering one’s self as a microbial ecosystem), to higher education (by incorporating our knowledge of the global ecological role and medical application of microbes), to the general public (by engagement through citizen-science projects). The greater inclusion of microbes in ecological education and outreach will not only help us appreciate the natural world we are part of, but will ultimately aid in building a citizenry better prepared to make informed deci...
Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet ... more Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet of alkaloid-containing arthropods. Geographic and temporal variation in alkaloid defense is common in poison frogs and is generally attributed to differences in the availability of alkaloid-containing arthropods. Variable chemical defense in poison frogs may have important consequences for predator-prey interactions, requiring a full understanding of the factors involved in explaining such variation. In the present study, we examine alkaloid variation in the dendrobatid poison frog Oophaga pumilio between males and females on Cayo Nancy (Isla Solarte), located in the Bocas del Toro archipelago of Panama. On average, females contained a significantly larger number and quantity of alkaloids when compared to males. Alkaloid composition varied significantly between males and females, illustrating that chemical defense in this population of O. pumilio is sex-dependent. The variation in alkaloids between sexes is attributed to differences in feeding and behavior between males and females. The majority of alkaloids present in the skin of O. pumilio appear to be of oribatid mite origin, supporting the importance of these dietary arthropods in the chemical defense of poison frogs. Animals that sequester chemical defenses from diet are dependent on specific food sources for protection against predation, 1-3 and therefore differences in the chemical composition, availability, or consumption of these dietary sources can result in variable defenses. 4-6 Variation in chemical defense is common among animals that sequester defenses and can have important consequences for predator-prey interactions. 7-9 The ecological and evolutionary implications of sequestering defenses have been well studied among some phytophagous arthropods, 1,10,11 but are not well understood in vertebrates. Among vertebrates, the ability to sequester defenses from diet has been proposed in birds of the genera Pitohui and Ifrita from Papua New Guinea 12 and experimentally demonstrated in the snake Rhabdophis tigrinus from Japan 13 and four lineages of poison frogs found worldwide (dendrobatids of Central and South America, bufonids of South America, mantellids of Madagascar, and myobatrachids of Australia 14). Poison frogs, which represent the best studied group, sequester alkaloid-based chemical defenses from dietary arthropods (including mites, ants, beetles, and millipedes 15). More than 800 alkaloids have been characterized in poison frog skins, reflecting the large diversity of alkaloids present in arthropods. 14 Geographic and temporal variation in alkaloid composition (the number, amount, and type of alkaloids) is common within and among species of poison frogs and appears to be largely related to the availability of alkaloid-containing arthropods 6,15-18 and differences in the amount and type of alkaloids present in arthropods. 6,19 Furthermore, alkaloids are accumulated over a lifetime, and juvenile dendrobatid poison frogs are known to contain smaller quantities of alkaloids than adults, 16,20 suggesting that variation in alkaloid composition is also related to frog age. Differences in alkaloid composition have also been proposed for individuals of different sex. 6,21 Recently, differences in the type and amount of certain alkaloids between males and females of the mantellid poison frog ⊥ Dedicated to the late Dr. John W. Daly of NIDDK, NIH, Bethesda, Maryland, for his pioneering work on bioactive natural products.
Two novel antibiotics, neocitreamicins I and II, were isolated from a fermentation broth of a Noc... more Two novel antibiotics, neocitreamicins I and II, were isolated from a fermentation broth of a Nocardia strain. This producing strain was obtained using an in situ diffusion chamber that facilitates the cultivation of soil microorganisms. The structures of neocitreamicins I and II were elucidated using UV, MS, and NMR data, and found to be related to the polycyclic xanthone antibiotics of the citreamicin class. The neocitreamicins showed in vitro activity against Gram-positive bacteria including strains of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis.
The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral... more The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral ecology, ecological immunology, and invasion biology. Since its introduction to the US in 1978, its invasion success has been attributed, in part, to a lack of parasites or parasitoids infecting this population. This is despite the number of parasites which infest the native population and the generalist polistine parasites and parasitoids documented in sympatric North American species. Multiple studies have cited low parasite pressure as evidence that the invasive population of P. dominulus is benefiting from a post-invasion release from enemies. Here, we present the first well documented case of parasitoidism of the invasive population of P. dominulus in North America.
ActinomycetesÑa group of antimicrobial producing bacteriaÑ have been successfully cultured and ch... more ActinomycetesÑa group of antimicrobial producing bacteriaÑ have been successfully cultured and characterized from the nest material of diverse arthropods. Some are symbionts that produce antimicrobial chemicals found to protect nest brood and resources from pathogenic microbes. Others have no known Þtness relationship with their associated insects, but have been found to produce antimicrobials in vitro. Consequently, insect nest material is being investigated as a new source of novel antimicrobial producing actinomycetes, which could be harnessed for therapeutic potential. To extend studies of actinomycete-insect associations beyond soil-substrate dwelling insects and wood boring excavators, we conducted a preliminary assessment of the actinomycetes within the nests of the paper wasp, Polistes dominulus (Christ). We found that actinomycetes were readily cultured from nest material across multiple invasive P. dominulus populationsÑincluding members of the genera Streptomyces, Micromonospora, and Actinoplanes. Thirty of these isolates were assayed for antimicrobial activity against the challenge bacteria Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Serratia marcescens, and Bacillus subtilis. Sixty percent of isolates inhibited the growth of at least one challenge strain. This study provides the Þrst assessment of bacteria associated with nests of P. dominulus, and the Þrst record of antimicrobial producing actinomycetes isolated from social wasps. We provide a new system to explore nest associated actinomycetes from a ubiquitous and cosmopolitan group of insects. KEY WORDS antibiotic, natural products, actinobacteria, Polistes dominula The sequences reported in this article have been deposited in the GenBank database (accession nos. HQ336264 ÐHQ336293).
The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral... more The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral ecology, ecological immunology, and invasion biology. Since its introduction to the US in 1978, its invasion success has been attributed, in part, to a lack of parasites or parasitoids infecting this population. This is despite the number of parasites which infest the native population and the generalist polistine parasites and parasitoids documented in sympatric North American species. Multiple studies have cited low parasite pressure as evidence that the invasive population of P. dominulus is benefiting from a post-invasion release from enemies. Here, we present the first well documented case of parasitoidism of the invasive population of P. dominulus in North America.
Title: Mucor nidicola sp. nov., a novel fungal species isolated from an invasive paper wasp nest.... more Title: Mucor nidicola sp. nov., a novel fungal species isolated from an invasive paper wasp nest. 1 Authors: A. A. Madden, A. M. Stchigel, J. Guarro, D. Sutton, P. T. Starks 2 Author Affiliations: 3 1 Department of Biology, Tufts University, 120 Dana Laboratories, 163 Packard Avenue, 4 Medford, Massachusetts, USA. 02155. 5 Unitat de Microbiologia, Facultat de Medicina i Ciencies de la Salut, IISPV, Universitat Rovira 6 i Virgili, Sant Llorenç 21, 43201-Reus, Spain 7 Department of Pathology, The University of Texas Health Science Center, San Antonio, Texas, 8 USA 78229-3900. 9 Corresponding Author: 10 A. A. Madden 11 Email: [email protected] 12 Phone: 617-627-4294 Fax: 617-627-3805 13 Running Title: Mucor nidicola sp. nov. isolated from a paper wasp nest 14 Subject Category: New Taxa 15 Subsection: Eukaryotic Micro-organisms. 16 *The GenBank accession numbers for the ITS1-5.8rDNA-ITS2 sequences of the Mucor spp. 17 strains examined in this study are provided in a supplementary ta...
ronment, National Science Foundation Research Experience for Undergraduates, and Tufts Graduate S... more ronment, National Science Foundation Research Experience for Undergraduates, and Tufts Graduate School of Arts, Sciences & Engineering. Field and Lab work assistance from Jon Soriano, Andrew Grassetti, and Kelly Nguyen. Photo credits: A.A.M. Results: My results are currently being prepared for publications in peer-reviewed journals. Copies of these publications will be made available at the office of Tufts Institute of the Environment. Summary: Polistes dominulus is a species of paper wasp which has recently invaded North America, where it is increasing its range with climate change and development. While many insects are known to transfer microbes from their nests to plants they visit, acting as microbial vectors, there have been no molecular assessments evaluating the microbes which inhabit the nest of P. dominulus and which may have been transferred along with their invasion. By culturing the microbes from P. dominulus nests throughout Massachusetts and using the natives species ...
Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet ... more Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet of alkaloid-containing arthropods. Geographic and temporal variation in alkaloid defense is common in poison frogs, and is generally attributed to differences in the availability of alkaloid-containing arthropods. Variable chemical defense in poison frogs may have important consequences for predator-prey interactions, requiring a full understanding of the factors involved in explaining such variation. In the present study, we examine alkaloid variation in the dendrobatid poison frog Oophaga pumilio between males and females on Cayo Nancy (Isla Solarte), located in the Bocas del Toro archipelago of Panama. On average, females contained a significantly larger number and quantity of alkaloids when compared to males. Alkaloid composition varied significantly between males and females, illustrating that chemical defense in this population of O. pumilio is sex-dependent. The variation in alkal...
Sugar‐seeking insects as a source of diverse bread‐making yeasts with enhanced attributes
Yeast
Insects represent a particularly interesting habitat in which to search for novel yeasts of value... more Insects represent a particularly interesting habitat in which to search for novel yeasts of value to industry. Insect-associated yeasts have the potential to have traits relevant to modern food and beverage production due to insect-yeast interactions, with such traits including diverse carbohydrate metabolisms, high sugar tolerance, and general stress tolerance. Here, we consider the potential value of insect-associated yeasts in the specific context of baking. We isolated 63 yeast strains from 13 species of hymenoptera from the United States, representing 37 yeast species from 14 genera. Screening for the ability to ferment maltose, a sugar important for bread production, resulted in the identification of 13 strains of Candida, Lachancea, and Pichia species. We assessed their ability to leaven dough. All strains produced baked loaves comparable to a commercial baking strain of Saccharomyces cerevisiae. The same thirteen strains were also grown under various sugar and salt conditions relevant to osmotic challenges experienced in the manufacturing processes and the production of sweet dough. We show that many of these yeast strains, most notably strains of Lachancea species, grow at a similar or higher rate and population size as commercial baker's yeast. We additionally assessed the comparative phenotypes and genetics of insect-associated S. cerevisiae strains unable to ferment maltose and identified baking-relevant traits, including variations in the HOG1 signaling pathway and diverse carbohydrate metabolisms. Our results suggest that non-conventional yeasts have high potential for baking, and more generally, showcase the success of bioprospecting in insects for identifying yeasts relevant for industrial uses.
The practice of sourdough bread-making is an ancient science that involves the development, maint... more The practice of sourdough bread-making is an ancient science that involves the development, maintenance, and use of a diverse and complex starter culture. The sourdough starter culture comes in many different forms and is used in bread-making at both artisanal and commercial scales, in countries all over the world. While there is ample scientific research related to sourdough, there is no standardized approach to using sourdough starters in science or the bread industry; and there are few recommendations on future directions for sourdough research. Our review highlights what is currently known about the microbial ecosystem of sourdough (including microbial succession within the starter culture), methods of maintaining sourdough (analogous to land management) on the path to bread production, and factors that influence the sensory qualities of the final baked product. We present new hypotheses for the successful management of sourdough starters and propose future directions for sourdo...
History and Domestication of Saccharomyces cerevisiae in Bread Baking
Frontiers in Genetics
The yeast Saccharomyces cerevisiae has been instrumental in the fermentation of foods and beverag... more The yeast Saccharomyces cerevisiae has been instrumental in the fermentation of foods and beverages for millennia. In addition to fermentations like wine, beer, cider, sake, and bread, S. cerevisiae has been isolated from environments ranging from soil and trees, to human clinical isolates. Each of these environments has unique selection pressures that S. cerevisiae must adapt to. Bread dough, for example, requires S. cerevisiae to efficiently utilize the complex sugar maltose; tolerate osmotic stress due to the semi-solid state of dough, high salt, and high sugar content of some doughs; withstand various processing conditions, including freezing and drying; and produce desirable aromas and flavors. In this review, we explore the history of bread that gave rise to modern commercial baking yeast, and the genetic and genomic changes that accompanied this. We illustrate the genetic and phenotypic variation that has been documented in baking strains and wild strains, and how this variation might be used for baking strain improvement. While we continue to improve our understanding of how baking strains have adapted to bread dough, we conclude by highlighting some of the remaining open questions in the field.
Humans have relied on sourdough starter microbial communities to make leavened bread for thousand... more Humans have relied on sourdough starter microbial communities to make leavened bread for thousands of years, but only a small fraction of global sourdough biodiversity has been characterized. Working with a community-scientist network of bread bakers, we determined the microbial diversity of 500 sourdough starters from four continents. In sharp contrast with widespread assumptions, we found little evidence for biogeographic patterns in starter communities. Strong co-occurrence patterns observed in situ and recreated in vitro demonstrate that microbial interactions shape sourdough community structure. Variation in dough rise rates and aromas were largely explained by acetic acid bacteria, a mostly overlooked group of sourdough microbes. Our study reveals the extent of microbial diversity in an ancient fermented food across diverse cultural and geographic backgrounds.
Sourdough starters are naturally occurring microbial communities in which the environment, ingred... more Sourdough starters are naturally occurring microbial communities in which the environment, ingredients, and bakers are potential sources of microorganisms. The relative importance of these pools remains unknown. Here, bakers from two continents used a standardized recipe and ingredients to make starters that were then baked into breads. We characterized the fungi and bacteria associated with the starters, bakers’ hands, and ingredients using 16S and internal transcribed spacer (ITS) rRNA gene amplicon sequencing and then measured dough acidity and bread flavor. Starter communities were much less uniform than expected, and this variation manifested in the flavor of the bread. Starter communities were most similar to those found in flour but shared some species with the bakers’ skin. While humans likely contribute microorganisms to the starters, the reverse also appears to be true. This bidirectional exchange of microorganisms between starters and bakers highlights the importance of m...
Many species of yeast are integral to human society. They produce many of our foods, beverages an... more Many species of yeast are integral to human society. They produce many of our foods, beverages and industrial chemicals, challenge us as pathogens, and provide models for the study of our own biology. However, few species are regularly studied and much of their ecology remains unclear, hindering the development of knowledge that is needed to improve the relationships between humans and yeasts. There is increasing evidence that insects are an essential component of ascomycetous yeast ecology. We propose a 'dispersal-encounter hypothesis' whereby yeasts are dispersed by insects between ephemeral, spatially disparate sugar resources, and insects, in turn, obtain the benefits of an honest signal from yeasts for the sugar resources. We review the relationship between yeasts and insects through three main examples: social wasps, social bees and beetles, with some additional examples from fruit flies. Ultimately, we suggest that over the next decades, consideration of these ecologi...
Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in... more Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, social wasps are abundant in vineyards where they feed on ripe berries and cause significant damage, while also dispersing yeasts involved in wine fermentation. Despite this, their possible role in disease facilitation and dispersal of grape rots has not been explored. We tested the hypothesis that the paper wasp Polistes dominulus could facilitate grape sour rot...
We spend most of our lives inside homes, surrounded by arthropods that impact our property as pes... more We spend most of our lives inside homes, surrounded by arthropods that impact our property as pests and our health as disease vectors and producers of sensitizing allergens. Despite their relevance to human health and well-being, we know relatively little about the arthropods that exist in our homes and the factors structuring their diversity. As previous work has been limited in scale by the costs and time associated with collecting arthropods and the subsequent morphological identification, we used a DNA-based method for investigating the arthropod diversity in homes via high-throughput marker gene sequencing of home dust. Settled dust samples were collected by citizen scientists from both inside and outside more than 700 homes across the United States, yielding the first continental-scale estimates of arthropod diversity associated with our residences. We were able to document food webs and previously unknown geographic distributions of diverse arthropods - from allergen producer...
Our planet is changing rapidly, and responding to the ensuing environmental challenges will requi... more Our planet is changing rapidly, and responding to the ensuing environmental challenges will require an informed citizenry that can understand the inherent complexity of ecological systems. However, microorganisms are usually neglected in the narratives that we use to understand nature. Here, we advocate for the inclusion of microbial ecology across education levels and delineate the often neglected benefits of incorporating microbes into ecology curricula. We provide examples across education levels, from secondary school (by considering one’s self as a microbial ecosystem), to higher education (by incorporating our knowledge of the global ecological role and medical application of microbes), to the general public (by engagement through citizen-science projects). The greater inclusion of microbes in ecological education and outreach will not only help us appreciate the natural world we are part of, but will ultimately aid in building a citizenry better prepared to make informed deci...
Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet ... more Poison frogs contain an alkaloid-based chemical defense that is sequestered directly from a diet of alkaloid-containing arthropods. Geographic and temporal variation in alkaloid defense is common in poison frogs and is generally attributed to differences in the availability of alkaloid-containing arthropods. Variable chemical defense in poison frogs may have important consequences for predator-prey interactions, requiring a full understanding of the factors involved in explaining such variation. In the present study, we examine alkaloid variation in the dendrobatid poison frog Oophaga pumilio between males and females on Cayo Nancy (Isla Solarte), located in the Bocas del Toro archipelago of Panama. On average, females contained a significantly larger number and quantity of alkaloids when compared to males. Alkaloid composition varied significantly between males and females, illustrating that chemical defense in this population of O. pumilio is sex-dependent. The variation in alkaloids between sexes is attributed to differences in feeding and behavior between males and females. The majority of alkaloids present in the skin of O. pumilio appear to be of oribatid mite origin, supporting the importance of these dietary arthropods in the chemical defense of poison frogs. Animals that sequester chemical defenses from diet are dependent on specific food sources for protection against predation, 1-3 and therefore differences in the chemical composition, availability, or consumption of these dietary sources can result in variable defenses. 4-6 Variation in chemical defense is common among animals that sequester defenses and can have important consequences for predator-prey interactions. 7-9 The ecological and evolutionary implications of sequestering defenses have been well studied among some phytophagous arthropods, 1,10,11 but are not well understood in vertebrates. Among vertebrates, the ability to sequester defenses from diet has been proposed in birds of the genera Pitohui and Ifrita from Papua New Guinea 12 and experimentally demonstrated in the snake Rhabdophis tigrinus from Japan 13 and four lineages of poison frogs found worldwide (dendrobatids of Central and South America, bufonids of South America, mantellids of Madagascar, and myobatrachids of Australia 14). Poison frogs, which represent the best studied group, sequester alkaloid-based chemical defenses from dietary arthropods (including mites, ants, beetles, and millipedes 15). More than 800 alkaloids have been characterized in poison frog skins, reflecting the large diversity of alkaloids present in arthropods. 14 Geographic and temporal variation in alkaloid composition (the number, amount, and type of alkaloids) is common within and among species of poison frogs and appears to be largely related to the availability of alkaloid-containing arthropods 6,15-18 and differences in the amount and type of alkaloids present in arthropods. 6,19 Furthermore, alkaloids are accumulated over a lifetime, and juvenile dendrobatid poison frogs are known to contain smaller quantities of alkaloids than adults, 16,20 suggesting that variation in alkaloid composition is also related to frog age. Differences in alkaloid composition have also been proposed for individuals of different sex. 6,21 Recently, differences in the type and amount of certain alkaloids between males and females of the mantellid poison frog ⊥ Dedicated to the late Dr. John W. Daly of NIDDK, NIH, Bethesda, Maryland, for his pioneering work on bioactive natural products.
Two novel antibiotics, neocitreamicins I and II, were isolated from a fermentation broth of a Noc... more Two novel antibiotics, neocitreamicins I and II, were isolated from a fermentation broth of a Nocardia strain. This producing strain was obtained using an in situ diffusion chamber that facilitates the cultivation of soil microorganisms. The structures of neocitreamicins I and II were elucidated using UV, MS, and NMR data, and found to be related to the polycyclic xanthone antibiotics of the citreamicin class. The neocitreamicins showed in vitro activity against Gram-positive bacteria including strains of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis.
The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral... more The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral ecology, ecological immunology, and invasion biology. Since its introduction to the US in 1978, its invasion success has been attributed, in part, to a lack of parasites or parasitoids infecting this population. This is despite the number of parasites which infest the native population and the generalist polistine parasites and parasitoids documented in sympatric North American species. Multiple studies have cited low parasite pressure as evidence that the invasive population of P. dominulus is benefiting from a post-invasion release from enemies. Here, we present the first well documented case of parasitoidism of the invasive population of P. dominulus in North America.
ActinomycetesÑa group of antimicrobial producing bacteriaÑ have been successfully cultured and ch... more ActinomycetesÑa group of antimicrobial producing bacteriaÑ have been successfully cultured and characterized from the nest material of diverse arthropods. Some are symbionts that produce antimicrobial chemicals found to protect nest brood and resources from pathogenic microbes. Others have no known Þtness relationship with their associated insects, but have been found to produce antimicrobials in vitro. Consequently, insect nest material is being investigated as a new source of novel antimicrobial producing actinomycetes, which could be harnessed for therapeutic potential. To extend studies of actinomycete-insect associations beyond soil-substrate dwelling insects and wood boring excavators, we conducted a preliminary assessment of the actinomycetes within the nests of the paper wasp, Polistes dominulus (Christ). We found that actinomycetes were readily cultured from nest material across multiple invasive P. dominulus populationsÑincluding members of the genera Streptomyces, Micromonospora, and Actinoplanes. Thirty of these isolates were assayed for antimicrobial activity against the challenge bacteria Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Serratia marcescens, and Bacillus subtilis. Sixty percent of isolates inhibited the growth of at least one challenge strain. This study provides the Þrst assessment of bacteria associated with nests of P. dominulus, and the Þrst record of antimicrobial producing actinomycetes isolated from social wasps. We provide a new system to explore nest associated actinomycetes from a ubiquitous and cosmopolitan group of insects. KEY WORDS antibiotic, natural products, actinobacteria, Polistes dominula The sequences reported in this article have been deposited in the GenBank database (accession nos. HQ336264 ÐHQ336293).
The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral... more The European paper wasp Polistes dominulus (Christ) is a model system in the fields of behavioral ecology, ecological immunology, and invasion biology. Since its introduction to the US in 1978, its invasion success has been attributed, in part, to a lack of parasites or parasitoids infecting this population. This is despite the number of parasites which infest the native population and the generalist polistine parasites and parasitoids documented in sympatric North American species. Multiple studies have cited low parasite pressure as evidence that the invasive population of P. dominulus is benefiting from a post-invasion release from enemies. Here, we present the first well documented case of parasitoidism of the invasive population of P. dominulus in North America.
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Papers by Anne Madden