183 research outputs found

    Editorial: Advances in the Understanding of the Commensal Eukaryota and Viruses of the Herbivore Gut

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    Herbivores play an important role in the survival of humanity, contributing food and textiles, as well as social and economic value. For decades, optimizing the productivity, health, welfare, and environmental footprint of herbivorous animals, particularly ruminant livestock, has been the subject of an extensive, global research effort. Much of this research effort has focused on the herbivore gut. The specialized nature of the herbivore digestive tract and its resident microbes enables the breakdown of highly fibrous plant materials, which are unable to be utilized by omnivores and carnivores. In recent years, the bacteria and methanogenic archaea have been the major focus of research efforts, with the other gut microbes being understudied in comparison

    Changing Attitudes towards Hepatitis B among Asian Americans: From Saving Face to Getting Serious

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    Background: Asian Americans have the highest prevalence of hepatitis B virus (HBV) in the US. The San Francisco Hep B Free (SFHBF) campaign aimed to increase awareness and access to HBV education and services among Asian Americans in San Francisco. Purpose: We sought to examine attitudes and knowledge among Asian Americans regarding HBV at baseline (2009) and benefits of the SFHBF outreach campaign four years later (2013). Methods: Four focus groups were conducted (n=45) in 2009, followed by in-depth interviews (n=40) in 2013. Results: In 2009, many participants were misinformed about HBV symptoms and transmission. They also reported stigma associated with HBV, which hindered Asian Americans from discussing the disease and seeking services. The 2013 interviews revealed that SFHBF had contributed towards awareness of HBV screenings and vaccinations, and also instilled acute seriousness that HBV could affect them directly. Conclusion: The in-depth interviews conducted in 2013 illustrated that there was less concern about “saving face,” but a shift to a level of seriousness associated with HBV. Future efforts among Asian Americans should continue to focus on self-efficacy regarding HBV prevention, including screening and vaccination

    Anomalous formation of trihydrogen cations from water on nanoparticles

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    The H3 + ion plays a key role in interstellar chemistry and can be formed from organic compounds upon interaction with charged particles or radiation. Here the authors demonstrate that H3 + can also be formed from water adsorbed on silica nanoparticles exposed to intense laser pulses, conditions that mimic the impact of charged particles on dust in astrophysical settings

    Horizontal Gene Transfer as an Indispensable Driver for Evolution of Neocallimastigomycota into a Distinct Gut-Dwelling Fungal Lineage

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    Survival and growth of the anaerobic gut fungi (AGF; Neocallimastigomycota) in the herbivorous gut necessitate the possession of multiple abilities absent in other fungal lineages. We hypothesized that horizontal gene transfer (HGT) was instrumental in forging the evolution of AGF into a phylogenetically distinct gut-dwelling fungal lineage. The patterns of HGT were evaluated in the transcriptomes of 27 AGF strains, 22 of which were isolated and sequenced in this study, and 4 AGF genomes broadly covering the breadth of AGF diversity. We identified 277 distinct incidents of HGT in AGF transcriptomes, with subsequent gene duplication resulting in an HGT frequency of 2 to 3.5% in AGF genomes. The majority of HGT events were AGF specific (91.7%) and wide (70.8%), indicating their occurrence at early stages of AGF evolution. The acquired genes allowed AGF to expand their substrate utilization range, provided new venues for electron disposal, augmented their biosynthetic capabilities, and facilitated their adaptation to anaerobiosis. The majority of donors were anaerobic fermentative bacteria prevalent in the herbivorous gut. This study strongly indicates that HGT indispensably forged the evolution of AGF as a distinct fungal phylum and provides a unique example of the role of HGT in shaping the evolution of a high-rank taxonomic eukaryotic lineage.IMPORTANCE The anaerobic gut fungi (AGF) represent a distinct basal phylum lineage (Neocallimastigomycota) commonly encountered in the rumen and alimentary tracts of herbivores. Survival and growth of anaerobic gut fungi in these anaerobic, eutrophic, and prokaryote-dominated habitats necessitates the acquisition of several traits absent in other fungal lineages. We assess here the role of horizontal gene transfer as a relatively fast mechanism for trait acquisition by the Neocallimastigomycota postsequestration in the herbivorous gut. Analysis of 27 transcriptomes that represent the broad diversity of Neocallimastigomycota identified 277 distinct HGT events, with subsequent gene duplication resulting in an HGT frequency of 2 to 3.5% in AGF genomes. These HGT events have allowed AGF to survive in the herbivorous gut by expanding their substrate utilization range, augmenting their biosynthetic pathway, providing new routes for electron disposal by expanding fermentative capacities, and facilitating their adaptation to anaerobiosis. HGT in the AGF is also shown to be mainly a cross-kingdom affair, with the majority of donors belonging to the bacteria. This study represents a unique example of the role of HGT in shaping the evolution of a high-rank taxonomic eukaryotic lineage

    New aspects and strategies for methane mitigation from ruminants.

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    The growing demand for sustainable animal production is compelling researchers to explore the potential approaches to reduce emissions of greenhouse gases from livestock that are mainly produced by enteric fermentation. Some potential solutions, for instance, the use of chemical inhibitors to reduce methanogenesis, are not feasible in routine use due to their toxicity to ruminants, inhibition of efficient rumen function or other transitory effects. Strategies, such as use of plant secondary metabolites and dietary manipulations have emerged to reduce the methane emission, but these still require extensive research before these can be recommended and deployed in the livestock industry sector. Furthermore, immunization vaccines for methanogens and phages are also under investigation for mitigation of enteric methanogenesis. The increasing knowledge of methanogenic diversity in rumen, DNA sequencing technologies and bioinformatics have paved the way for chemogenomic strategies by targeting methane producers. Chemogenomics will help in finding target enzymes and proteins, which will further assist in the screening of natural as well chemical inhibitors. The construction of a methanogenic gene catalogue through these approaches is an attainable objective. This will lead to understand the microbiome function, its relation with the host and feeds, and therefore, will form the basis of practically viable and eco-friendly methane mitigation approaches, while improving the ruminant productivity

    Laser based series interconnection of chalcopyrite und perovskite solar cells Analysis of material modifications and implications for achieving small dead area widths

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    Both nanosecond pulses and picosecond laser pulses are used for P2 patterning of chalcopyrite Cu In,Ga Se2, CIGSe and metal halide perovskite solar cell absorber layers. For CIGSe, the range of the modified material visualized by photoluminescence imaging is significantly wider than the actual physical linewidth, since energy input by the laser pulses leads to material modification in the vicinity of the scribed lines. This effect does not occur with the perovskite absorber layers, where there is no apparent influence on the edge regions. From numerical calculations of the temperature depth profiles and the surface temperature distributions it is concluded that this effect is due to the significantly lower perovskite absorber layer thickness compared to CIGSe and the nevertheless significantly higher laser fluence required for perovskite ablation. The unaffected edge regions around the P2 line in the perovskite enabled a reduction of the dead area width in the fabrication of 3 segmented mini modules, which could be significantly reduced from 430 to 230 m, while increasing the aperture area power conversion efficiency and also the geometric fill factor, which could be increased up to 94.

    PCR and Omics Based Techniques to Study the Diversity, Ecology and Biology of Anaerobic Fungi:Insights, Challenges, and Opportunities

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    Anaerobic fungi (phylum Neocallimastigomycota) are common inhabitants of the digestive tract of mammalian herbivores, and in the rumen, can account for up to 20% of the microbial biomass. Anaerobic fungi play a primary role in the degradation of lignocellulosic plant material. They also have a syntrophic interaction with methanogenic archaea, which increases their fiber degradation activity. To date, nine anaerobic fungal genera have been described, with further novel taxonomic groupings known to exist based on culture-independent molecular surveys. However, the true extent of their diversity may be even more extensively underestimated as anaerobic fungi continue being discovered in yet unexplored gut and non-gut environments. Additionally many studies are now known to have used primers that provide incomplete coverage of the Neocallimastigomycota. For ecological studies the internal transcribed spacer 1 region (ITS1) has been the taxonomic marker of choice, but due to various limitations the large subunit rRNA (LSU) is now being increasingly used. How the continued expansion of our knowledge regarding anaerobic fungal diversity will impact on our understanding of their biology and ecological role remains unclear; particularly as it is becoming apparent that anaerobic fungi display niche differentiation. As a consequence, there is a need to move beyond the broad generalization of anaerobic fungi as fiber-degraders, and explore the fundamental differences that underpin their ability to exist in distinct ecological niches. Application of genomics, transcriptomics, proteomics and metabolomics to their study in pure/mixed cultures and environmental samples will be invaluable in this process. To date the genomes and transcriptomes of several characterized anaerobic fungal isolates have been successfully generated. In contrast, the application of proteomics and metabolomics to anaerobic fungal analysis is still in its infancy. A central problem for all analyses, however, is the limited functional annotation of anaerobic fungal sequence data. There is therefore an urgent need to expand information held within publicly available reference databases. Once this challenge is overcome, along with improved sample collection and extraction, the application of these techniques will be key in furthering our understanding of the ecological role and impact of anaerobic fungi in the wide range of environments they inhabit
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