• Energy Research
• medical and health sciences close
• AU close
• University of North Texas close

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in the soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.

Development of cellulosic biofuels from non-food crops is currently an area of intense research interest. Tailoring depolymerizing enzymes to particular feedstocks and pretreatment conditions is one promising avenue of research in this area. Here we added a green-waste compost inoculum to switchgrass (Panicum virgatum) and simulated thermophilic composting in a bioreactor to select for a switchgrass-adapted community and to facilitate targeted discovery of glycoside hydrolases. Small-subunit (SSU) rRNA-based community profiles revealed that the microbial community changed dramatically between the initial and switchgrass-adapted compost (SAC) with some bacterial populations being enriched over 20-fold. We obtained 225 Mbp of 454-titanium pyrosequence data from the SAC community and conservatively identified 800 genes encoding glycoside hydrolase domains that were biased toward depolymerizing grass cell wall components. Of these, approximately 10% were putative cellulases mostly belonging to families GH5 and GH9. We synthesized two SAC GH9 genes with codon optimization for heterologous expression in Escherichia coli and observed activity for one on carboxymethyl cellulose. The active GH9 enzyme has a temperature optimum of 50 degrees C and pH range of 5.5 to 8 consistent with the composting conditions applied. We demonstrate that microbial communities adapt to switchgrass decomposition using simulated composting condition and that full-length genes can be identified from complex metagenomic sequence data, synthesized and expressed resulting in active enzyme.

Cellular responses to changes in pressure are implicated in numerous disease processes. In glaucoma apoptosis of retinal ganglion cells (RGCs) is associated with elevated intra-ocular pressure, however, the exact cellular mechanisms remain unclear. We have previously shown that pressure can induce apoptosis in B35 and PC12 neuronal cell lines, using an in vitro model for pressure elevation. A novel RGC line allows us to study the effects of pressure on retinal neurons. 'RGC-5' cultures were subjected to elevated ambient hydrostatic pressure conditions in our model. Experimental pressure conditions were 100 mm Hg and 30 mm Hg, representing acute (high) and chronic (lower-pressure) glaucoma, and 15 mm Hg for normal intra-ocular pressure, set above atmospheric pressure for 2 h. Negative controls were treated identically except for the application of pressure, while positive controls were generated by treatment with a known apoptotic stimulus. Apoptosis was determined by a combination of cell morphology and specific TUNEL and Annexin V fluorescent markers. These were assessed simultaneously by laser scanning cytometry (LSC), which also enabled quantitative marker analysis. RGC-5 neurons showed a significantly increased proportion of apoptotic cells compared with controls; maximal at 100 mm Hg, moderate at 30 mm Hg and not statistically significant at 15 mm Hg. This graded response, proportionate to the level of pressure elevation, is representative of the severity of analogous clinical settings (acute, chronic glaucoma and normal). These results complement earlier findings of pressure-induced apoptosis in other neuronal cultures. They suggest the possibility of novel mechanisms of pressure-related mechanotransduction and cell death, relevant to the pathogenesis of diseases such as glaucoma.

Ethanol is one of the most widely used recreational drugs in the world. At high concentrations, it can induce carotid artery vasoconstriction. Hyperthermia potentiates its effects resulting in carotid artery vasoconstriction at any concentration. The aim of this study is to investigate the interaction between ethanol and heating and to understand the underlying mechanisms leading to their synergistic effect.Isometric tension of rabbit carotid artery ring segments suspended in organ baths filled with Krebs solution was recorded. Different concentrations of ethanol were examined at 37°C and during temperature elevation to39-43°C. Capsaicin and capsazepine were used to examine the mechanism of action of ethanol.Ethanol induced contraction at 37°C when the concentration reached 100mM. Contraction was observed at any concentration at higher temperatures. Ethanol potentiated heat-induced contraction. Capsaicin, the vanilloid receptor subtype1 (TRPV1) agonist, potentiated the vasoconstriction due to heating. While capsazepine, TRPV1 antagonist, abolished the effect of ethanol and its potentiation of heating-induced contraction, but it did not abolish the heating effect.Ethanol's mechanism of action and its effect on heating induced-vasoconstriction of the carotid artery is being mediated by TRPV1. The combination of ethanol and hyperthermia can lead to a synergistic effect on carotid vasoconstriction. This effect may induce brain damage and heat stroke. Development of new drugs act as TRPV1 antagonist can be used to prevent these fatal effects.

AbstractPlanetary health provides a perspective of ecological interdependence that connects the health and vitality of individuals, communities, and Earth's natural systems. It includes the social, political, and economic ecosystems that influence both individuals and whole societies. In an era of interconnected grand challenges threatening health of all systems at all scales, planetary health provides a framework for cross‐sectoral collaboration and unified systems approaches to solutions. The field of allergy is at the forefront of these efforts. Allergic conditions are a sentinel measure of environmental impact on human health in early life—illuminating how ecological changes affect immune development and predispose to a wider range of inflammatory noncommunicable diseases (NCDs). This shows how adverse macroscale ecology in the Anthropocene penetrates to the molecular level of personal and microscale ecology, including the microbial systems at the foundations of all ecosystems. It provides the basis for more integrated efforts to address widespread environmental degradation and adverse effects of maladaptive urbanization, food systems, lifestyle behaviors, and socioeconomic disadvantage. Nature‐based solutions and efforts to improve nature‐relatedness are crucial for restoring symbiosis, balance, and mutualism in every sense, recognizing that both personal lifestyle choices and collective structural actions are needed in tandem. Ultimately, meaningful ecological approaches will depend on placing greater emphasis on psychological and cultural dimensions such as mindfulness, values, and moral wisdom to ensure a sustainable and resilient future.

Producing cellulosic biofuels from plant material has recently emerged as a key US Department of Energy goal. For this technology to be commercially viable on a large scale, it is critical to make production cost efficient by streamlining both the deconstruction of lignocellulosic biomass and fuel production. Many natural ecosystems efficiently degrade lignocellulosic biomass and harbor enzymes that, when identified, could be used to increase the efficiency of commercial biomass deconstruction. However, ecosystems most likely to yield relevant enzymes, such as tropical rain forest soil in Puerto Rico, are often too complex for enzyme discovery using current metagenomic sequencing technologies. One potential strategy to overcome this problem is to selectively cultivate the microbial communities from these complex ecosystems on biomass under defined conditions, generating less complex biomass-degrading microbial populations. To test this premise, we cultivated microbes from Puerto Rican soil or green waste compost under precisely defined conditions in the presence dried ground switchgrass (Panicum virgatum L.) or lignin, respectively, as the sole carbon source. Phylogenetic profiling of the two feedstock-adapted communities using SSU rRNA gene amplicon pyrosequencing or phylogenetic microarray analysis revealed that the adapted communities were significantly simplified compared to the natural communities from which they were derived. Several members of the lignin-adapted and switchgrass-adapted consortia are related to organisms previously characterized as biomass degraders, while others were from less well-characterized phyla. The decrease in complexity of these communities make them good candidates for metagenomic sequencing and will likely enable the reconstruction of a greater number of full-length genes, leading to the discovery of novel lignocellulose-degrading enzymes adapted to feedstocks and conditions of interest.

In the past 15 years, a major research enterprise has emerged that is aimed at understanding associations between geographic and contextual features of the environment (especially the built environment) and elements of human energy balance, including diet, weight, and physical activity. Here we highlight aspects of this research area with a particular focus on research and opportunities in the United States as an example. We address four main areas: 1) The importance of valid and comparable data concerning behavior across geographies, 2) The ongoing need to identify and explore new environmental variables, 3) The challenge of identifying the causally relevant context, and 4) The pressing need for stronger study designs and analytical methods. Additionally, we discuss existing sources of geo-referenced health data which might be exploited by interdisciplinary research teams, personnel challenges and some aspects of funding for geospatial research by the US National Institutes of Health in the past decade, including funding for international collaboration and training opportunities.