Scholarly Work - Montana INBRE (IDeA Networks of Biomedical Research Excellence)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/15470
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Item Control of barley (Hordeum vulgare L.) development and senescence by the interaction between a chromosome six grain protein content locus, day length, and vernalization(2011-11) Parrott, David L.; Downs, Eric P.; Fischer, Andreas M.Regulatory processes controlling traits such as anthesis timing and whole-plant senescence are of primary importance for reproductive success and for crop quality and yield. It has previously been demonstrated that the presence of alleles associated with high grain protein content (GPC) at a locus on barley chromosome six leads to accelerated leaf senescence, and to strong (>10-fold) up-regulation of several genes which may be involved in senescence control. One of these genes (coding for a glycine-rich RNA-binding protein termed HvGR-RBP1) exhibits a high degree of similarity to Arabidopsis glycine-rich RNA-binding protein 7 (AtGRP7), which has been demonstrated to accelerate flowering under both long-day (LD) and short-day (SD) conditions, but not after vernalization. Development of near-isogenic barley lines, differing in the allelic state of the GPC locus, was compared from the seedling stage to maturity under both SD and LD and after vernalization under LD. Intriguingly, pre-anthesis plant development [measured by leaf emergence timing and pre-anthesis (sequential) leaf senescence] was enhanced in high-GPC germplasm. Differences were more pronounced under SD than under LD, but were eliminated by vernalization, associating observed effects with floral induction pathways. By contrast, differences in post-anthesis flag leaf and whole-plant senescence between low- and high-GPC germplasm persisted under all tested conditions, indicating that the GPC locus, possibly through HvGR-RBP1, impacts on both developmental stages. Detailed molecular characterization of this experimental system may allow the dissection of cross-talk between signalling pathways controlling early plant and floral development on one side, and leaf/whole-plant senescence on the other side.Item The Prevalence of STIV c92-Like Proteins in Acidic Thermal Environments(2011-05) Snyder, Jamie C.; Bolduc, Benjamin I.; Bateson, Mary M.; Young, Mark J.A new type of viral-induced lysis system has recently been discovered for two unrelated archaeal viruses, STIV and SIRV2. Prior to the lysis of the infected host cell, unique pyramid-like lysis structures are formed on the cell surface by the protrusion of the underlying cell membrane through the overlying external S-layer. It is through these pyramid structures that assembled virions are released during lysis. The STIV viral protein c92 is responsible for the formation of these lysis structures. We searched for c92-like proteins in viral sequences present in multiple viral and cellular metagenomic libraries from Yellowstone National Park acidic hot spring environments. Phylogenetic analysis of these proteins demonstrates that, although c92-like proteins are detected in these environments, some are quite divergent and may represent new viral families. We hypothesize that this new viral lysis system is common within diverse archaeal viral populations found within acidic hot springs.Item Virus-like Particle-Induced Protection against MRSA Pneumonia Is Dependent on IL-13 and Enhancement of Phagocyte Function(2012-07) Rynda-Apple, Agnieszka; Dobrinen, Erin; McAlpine, Mark; Read, Amanda; Harmsen, Ann L.; Richert, Laura E.; Calverley, Matthew; Pallister, Kyler; Voyich, Jovanka M.; Wiley, James A.; Johnson, Ben; Young, Mark J.; Douglas, Trevor; Harmsen, Allen G.The importance of the priming of the lung environment by past infections is being increasingly recognized. Exposure to any given antigen can either improve or worsen the outcome of subsequent lung infections, depending on the immunological history of the host. Thus, an ability to impart transient alterations in the lung environment in anticipation of future insult could provide an important novel therapy for emerging infectious diseases. In this study, we show that nasal administration of virus-like particles (VLPs) before, or immediately after, lethal challenge with methicillin-resistant Staphylococcus aureus (MRSA) of mice i) ensures complete recovery from lung infection and near absolute clearance of bacteria within 12 hours of challenge, ii) reduces host response-induced lung tissue damage, iii) promotes recruitment and efficient bacterial clearance by neutrophils and CD11c+ cells, and iv) protects macrophages from MRSA-induced necrosis. VLP-mediated protection against MRSA relied on innate immunity. Complete recovery occurred in VLP-dosed mice with severe combined immunodeficiency, but not in wild-type mice depleted of either Ly6G+ or CD11c+ cells. Early IL-13 production associated with VLP-induced CD11c+ cells was essential for VLP-induced protection. These results indicate that VLP-induced alteration of the lung environment protects the host from lethal MRSA pneumonia by enhancing phagocyte recruitment and killing and by reducing inflammation-induced tissue damage via IL-13–dependent mechanisms.Item A major grain protein content locus on barley (Hordeum vulgare L.) chromosome 6 influences flowering time and sequential leaf senescence(2010-06) Lacerenza, Joseph A.; Parrott, David L.; Fischer, Andreas M.Timing of various developmental stages including anthesis and whole-plant (‘monocarpic’) senescence influences yield and quality of annual crops. While a correlation between flowering/seed filling and whole-plant senescence has been observed in many annuals, it is unclear how the gene networks controlling these processes interact. Using near-isogenic germplasm, it has previously been demonstrated that a grain protein content (GPC) locus on barley chromosome 6 strongly influences the timing of post-anthesis flag leaf senescence, with high-GPC germplasm senescing early. Here, it is shown that the presence of high-GPC allele(s) at this locus also accelerates pre-anthesis plant development. While floral transition at the shoot apical meristem (SAM; determined by the presence of double ridges) occurred simultaneously, subsequent development was faster in the high- than in the low-GPC line, and anthesis occurred on average 5 d earlier. Similarly, sequential (pre-anthesis) leaf senescence was slightly accelerated, but only after differences in SAM development became visible. Leaf expression levels of four candidate genes (from a list of genes differentially regulated in post-anthesis flag leaves) were much higher in the high-GPC line even before faster development of the SAM became visible. One of these genes may be a functional homologue of Arabidopsis glycine-rich RNA-binding protein 7, which has previously been implicated in the promotion of flowering. Together, the data establish that the GPC locus influences pre- and post-anthesis barley development and senescence, and set the stage for a more detailed analysis of the interactions between the molecular networks controlling these important life history traits.Item Metagenomes from high-temperature chemotrophic systems reveal geochemical controls on microbial community structure and function(2010-03) Inskeep, William P.; Rusch, Douglas B.; Jay, Zackary J.; Herrgard, Markus J.; Kozubal, Mark A.; Richardson, Toby H.; Macur, Richard E.; Hamamura, Natsuko; Jennings, Ryan deM.; Fouke, Bruce W.; Reysenbach, Anna-Louise; Roberto, Frank; Young, Mark J.; Schwartz, Ariel; Boyd, Eric S.; Badger, Jonathan H.; Mathur, Eric J.; Ortmann, Alice C.; Bateson, Mary M.; Geesey, Gill G.; Frazier, MarvinThe Yellowstone caldera contains the most numerous and diverse geothermal systems on Earth, yielding an extensive array of unique high-temperature environments that host a variety of deeply-rooted and understudied Archaea, Bacteria and Eukarya. The combination of extreme temperature and chemical conditions encountered in geothermal environments often results in considerably less microbial diversity than other terrestrial habitats and offers a tremendous opportunity for studying the structure and function of indigenous microbial communities and for establishing linkages between putative metabolisms and element cycling. Metagenome sequence (14–15,000 Sanger reads per site) was obtained for five high-temperature (>65°C) chemotrophic microbial communities sampled from geothermal springs (or pools) in Yellowstone National Park (YNP) that exhibit a wide range in geochemistry including pH, dissolved sulfide, dissolved oxygen and ferrous iron. Metagenome data revealed significant differences in the predominant phyla associated with each of these geochemical environments. Novel members of the Sulfolobales are dominant in low pH environments, while other Crenarchaeota including distantly-related Thermoproteales and Desulfurococcales populations dominate in suboxic sulfidic sediments. Several novel archaeal groups are well represented in an acidic (pH 3) Fe-oxyhydroxide mat, where a higher O2 influx is accompanied with an increase in archaeal diversity. The presence or absence of genes and pathways important in S oxidation-reduction, H2-oxidation, and aerobic respiration (terminal oxidation) provide insight regarding the metabolic strategies of indigenous organisms present in geothermal systems. Multiple-pathway and protein-specific functional analysis of metagenome sequence data corroborated results from phylogenetic analyses and clearly demonstrate major differences in metabolic potential across sites. The distribution of functional genes involved in electron transport is consistent with the hypothesis that geochemical parameters (e.g., pH, sulfide, Fe, O2) control microbial community structure and function in YNP geothermal springs.