Project description:Bioelectrochemical systems employing mixed microbial communities as biocatalysts are gaining importance as potential renewable energy, bioremediation, or biosensing devices. While we are beginning to understand how individual microorganism species interact with an electrode as electron donor, not much is known about the interactions between different microbial species in a community. Here, we compare the bioelectrochemical performance of Shewanella oneidensis in a pure-culture and in a co-culture with the homolactic acid fermenter Lactococcus lactis. While S. oneidensis alone can only use lactate as electron donor for current production, the co-culture is able to convert glucose into current with a similar coulombic efficiency of approximately 17%, respectively. With (electro)-chemical analysis and transcription profiling, we found that the BES performance and S. oneidensis physiology were not significantly different whether grown as a pure- or co-culture. These co-culture experiments represent a first step in understanding microbial interactions in BES communities with the goal to design complex microbial communities, which specifically convert target substrates into electricity. Further, for the first time, we elucidated S. oneidensis gene expression with an electrode as the only electron acceptor. The expression pattern confirms many previous studies regarding the enzymatic requirements for electrode respiration, and it generates new hypotheses on the functions of proteins, which are so far not known to be involved in electrode respiration.
Project description:Bioelectrochemical systems employing mixed microbial communities as biocatalysts are gaining importance as potential renewable energy, bioremediation, or biosensing devices. While we are beginning to understand how individual microorganism species interact with an electrode as electron donor, not much is known about the interactions between different microbial species in a community. Here, we compare the bioelectrochemical performance of Shewanella oneidensis in a pure-culture and in a co-culture with the homolactic acid fermenter Lactococcus lactis. While S. oneidensis alone can only use lactate as electron donor for current production, the co-culture is able to convert glucose into current with a similar coulombic efficiency of approximately 17%, respectively. With (electro)-chemical analysis and transcription profiling, we found that the BES performance and S. oneidensis physiology were not significantly different whether grown as a pure- or co-culture. These co-culture experiments represent a first step in understanding microbial interactions in BES communities with the goal to design complex microbial communities, which specifically convert target substrates into electricity. Further, for the first time, we elucidated S. oneidensis gene expression with an electrode as the only electron acceptor. The expression pattern confirms many previous studies regarding the enzymatic requirements for electrode respiration, and it generates new hypotheses on the functions of proteins, which are so far not known to be involved in electrode respiration. The BES was either operated with S. oneidensis alone, fed with lactate, or it was operated with S. oneidensis and L. lactis with glucose as primary substrate. The basic medium was a modified M4 medium containing 0.5 g/L yeast extract, 0.5 g/L trypton and 5 g/L glycerol phosphate, besides the commen M4 incredients. S. oneidensis oxidizes lactate to acetate and electrons in a BES - the latter generate a current at a graphite anode. The anode biofilm was harvested after about 4 weeks of continuous BES operation and subjected to total RNA extraction.
Project description:We established simple synthetic microbial communities in a microcosm model system to determine the mechanisms that underlay cross-feeding in microbial methane-consuming communities. Co-occurring strains from Lake Washington sediment were used that are involved in methane consumption, a methanotroph and two non-methanotrophic methylotrophs.
Project description:Understanding and quantifying the effects of environmental factors influencing the variation of abundance and diversity of microbial communities was a key theme of ecology. For microbial communities, there were two factors proposed in explaining the variation in current theory, which were contemporary environmental heterogeneity and historical events. Here, we report a study to profile soil microbial structure, which infers functional roles of microbial communities, along the latitudinal gradient from the north to the south in China mainland, aiming to explore potential microbial responses to external condition, especially for global climate changes via a strategy of space-for-time substitution. Using a microarray-based metagenomics tool named GeoChip 5.0, we showed that microbial communities were distinct for most but not all of the sites. Using substantial statistical analyses, exploring the dominant factor in influencing the soil microbial communities along the latitudinal gradient. Substantial variations were apparent in nutrient cycling genes, but they were in line with the functional roles of these genes. 300 samples were collected from 30 sites along the latitudinal gradient, with 10 replicates in every site
Project description:Understanding and quantifying the effects of environmental factors influencing the variation of abundance and diversity of microbial communities was a key theme of ecology. For microbial communities, there were two factors proposed in explaining the variation in current theory, which were contemporary environmental heterogeneity and historical events. Here, we report a study to profile soil microbial structure, which infers functional roles of microbial communities, along the latitudinal gradient from the north to the south in China mainland, aiming to explore potential microbial responses to external condition, especially for global climate changes via a strategy of space-for-time substitution. Using a microarray-based metagenomics tool named GeoChip 5.0, we showed that microbial communities were distinct for most but not all of the sites. Using substantial statistical analyses, exploring the dominant factor in influencing the soil microbial communities along the latitudinal gradient. Substantial variations were apparent in nutrient cycling genes, but they were in line with the functional roles of these genes.
Project description:Although Cochliobolus miyabeanus is an important fungal leaf pathogen on rice plants worldwide, it is largely neglected by molecular plant phytopathologists. To shed new light on the molecular and genetic basis of the rice – C. miyabeanus interaction, we compared the transcriptome of rice leaves 12h post inoculation to uninfected leaves. Even though usable sources of resistance against brown spot disease caused by C. miyabeanus are scarce, silicon application emerges as a sustainable protection strategy. Many articles report the beneficial effect of silicon on brown spot resistance. however the underlying mechanisms remain largely unclear. The influence of silicon application on the transcriptome of healthy and infected rice leaves 12hpi was compared as well in an attempt to disentangle the modulation of silicon-induced brown spot resistance.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3)
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals.
Project description:To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. Acid mine drainage (AMD) presents numerous problems to the aquatic life and surrounding ecosystems. However, little is known about the geographic distribution, diversity, composition, structure and function of AMD microbial communities. In this study, we analyzed the geographic distribution of AMD microbial communities from twenty sites using restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, and the results showed that AMD microbial communities were geographically distributed and had high variations among different sites. Then an AMD-specific microarray was used to further analyze nine AMD microbial communities, and showed that those nine AMD microbial communities had high variations measured by the number of detected genes, overlapping genes between samples, unique genes, and diversity indices. Statistical analyses indicated that the concentrations of Fe, S, Ca, Mg, Zn, Cu and pH had strong impacts on both phylogenetic and functional diversity, composition, and structure of AMD microbial communities. This study provides insights into our understanding of the geographic distribution, diversity, composition, structure and functional potential of AMD microbial communities and key environmental factors shaping them. This study investigated the geographic distribution of Acid Mine Drainages microbial communities using a 16S rRNA gene-based RFLP method and the diversity, composition and structure of AMD microbial communities phylogenetically and functionally using an AMD-specific microarray which contained 1,072 probes ( 571 related to 16S rRNA and 501 related to functional genes). The functional genes in the microarray were involved in carbon metabolism (158), nitrogen metabolism (72), sulfur metabolism (39), iron metabolism (68), DNA replication and repair (97), metal-resistance (27), membrane-relate gene (16), transposon (13) and IST sequence (11).