Apparatus enables accurate determination of alkali oxides in alkali metals

Evacuated apparatus determines the alkali oxide content of an alkali metal by separating the metal from the oxide by amalgamation with mercury. The apparatus prevents oxygen and moisture from inadvertently entering the system during the sampling and analytical procedure

Evolution and Genetic Diversity in Streptococcus pneumoniae

The relative contributions of point mutations and intergenomic recombination via lateral gene transfer (LGT) determine the population structure and evolutionary style for a given bacterial species. Streptococcus pneumoniae has a weakly clonal population structure; adaptive clonal complexes can be detected; however, these can also be rapidly lost due to the high rate of recombination. To characterize the diversity of pneumococcal isolates in clonal complex, and to elucidate possible mechanisms for the long-term stability of such complexes, 35 serotype 6B strains belonging to a previously identified clonal complex, CC14, were assayed by Comparative Genome Hybridization (CGH) and Multi Locus Sequence Typing (MLST). Additionally, six isolates of serotype 4, which is known to be less diverse than serotype 6B, were also analyzed. Genome plasticity in pneumococci is observed in the acquisition of antibiotic resistance and epidemiological shifts in serotype. LGT is a prime mediator. The scope of transformation, or the number of unlinked and unselected recombination events that occur simultaneously, is an aspect not fully understood. Whole genome variation, particularly unselected exchanges, was followed after in vitro transformation by analyzing transformants along with their respective donor and recipient parent by CGH. Transformants were capsule-switch mutants, selected by one of two means: 1) screening for colony size in a TIGR4 cps::Janus recipient x GA71_19F donor transformation, and 2) selected for the acquisition of single-step resistance to penicillin or cefotaxime in a TIGR4 x GA71_19F cross; this co-selected for replacement of the capsule region because pbp2X and pbp1A are adjacent. Nearly 40 genes were found absent or divergent in at least one of the capsule-switch mutants; sequencing was used to verify CGH results. Some were unlinked to the capsule locus, indicating multiple recombination events per transformation. Unlinked variation was observed in at least 5 of 8 capsule-switch transformations. Furthermore, a gene annotated as hypothetical, SP1581, was implicated in resistance to cefotaxime. CGH confirms that transfer of gene regions up to 45.9 kb is possible during natural transformation and unselected variation is common. This supports the hypothesis that transformation is capable of driving the high level of genome plasticity in S. pneumoniae

Defining Landscape-Scale Collaboration as Used to Restore Forests and Reduce Catastrophic Wildfires

In this article, I explore the distinctive characteristics of landscape-scale collaboration in the context of forest resource management in the United States. The United States (US) is experiencing a significant increase in acres burned by wildfire in the wildland-urban interface zone, exacting a heavy toll on human life, health, property, and livelihoods. The US Forest Service’s Collaborative Forest Landscape Restoration (CFLR) Program demonstrates an effective approach to reducing risk of catastrophic wildfire through collaborative forest restoration work at the landscape scale. This is the first in a series of articles building toward a grounded theory to guide development of the capacities needed to collaborate at this scale. The study is based on thirteen interviews and nine focus groups with CFLR Program participants. This article addresses the research question: What is unique about collaborating at the landscape scale? Findings include five characteristics that together define this form of collaboration and insights on how participants framed their focal landscapes. I explain the catalyst for these collaboratives, scope of the study, and context for my involvement. I review pertinent literature and then describe the methods I employed in this study. Finally, I present and discuss my findings and offer suggestions for further research and management recommendations. Subsequent articles in this series will identify the capacities needed to collaborate in this context, present a theory informing strategies for cultivating these capacities, offer additional management and policy recommendations, and suggest curricular implications

Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories

In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphse plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered

Illuminating Capacity-Building Strategies for Landscape-Scale Collaborative Forest Management Through Constructivist Grounded Theory

This dissertation uses the constructivist grounded theory methods of Charmaz (2011) to explore: 1) the unique characteristics of landscape-scale collaboration; 2) implications for collaborative capacity-building strategies; and 3) the relationship between conflict, landscape-scale collaboration, and conflict resolution. The study was conducted through the US Forest Service\u27s Collaborative Forest Landscape Restoration Program (CFLRP). In the 1980s and 1990s, national forest management conflicts brought the forest industry to a standstill, with many jobs lost. In addition, historic fire suppression practices have made our national forests highly vulnerable to catastrophic wildfire. Many have strong opinions about what should be done and how. The proposed substantive theory suggests landscape-scale collaboration can serve as a conflict prevention, problem solving, or conflict resolution venue and offer opportunities for remarkable efficiencies in forest restoration as well as profoundly restorative transformation in ecological, social, economic, personal, and spiritual dimensions. It identifies unique characteristics of collaboration at this scale; suggests that realizing benefits depends on collaborative capacities at the collaborator, constituent organization, collaborative stakeholder group, and sponsoring organization levels, and on mastering nine challenges; and suggests eight implications for collaborative capacity building strategies. The study contributes to forest restoration, reduced loss of life and livelihood, and economic recovery by contributing to CFLRP effectiveness. It contributes to the field of conflict resolution by: illuminating the collaboration / conflict resolution relationship; a particular application of collaboration; related sources of conflict; and conflict resolution strategies. It advances new directions of study for conflict resolution scholars--i.e., how to help agencies and groups strengthen their collaborative capacities

Epigenetically-Inherited Centromere and Neocentromere DNA Replicates Earliest in S-Phase

Eukaryotic centromeres are maintained at specific chromosomal sites over many generations. In the budding yeast Saccharomyces cerevisiae, centromeres are genetic elements defined by a DNA sequence that is both necessary and sufficient for function; whereas, in most other eukaryotes, centromeres are maintained by poorly characterized epigenetic mechanisms in which DNA has a less definitive role. Here we use the pathogenic yeast Candida albicans as a model organism to study the DNA replication properties of centromeric DNA. By determining the genome-wide replication timing program of the C. albicans genome, we discovered that each centromere is associated with a replication origin that is the first to fire on its respective chromosome. Importantly, epigenetic formation of new ectopic centromeres (neocentromeres) was accompanied by shifts in replication timing, such that a neocentromere became the first to replicate and became associated with origin recognition complex (ORC) components. Furthermore, changing the level of the centromere-specific histone H3 isoform led to a concomitant change in levels of ORC association with centromere regions, further supporting the idea that centromere proteins determine origin activity. Finally, analysis of centromere-associated DNA revealed a replication-dependent sequence pattern characteristic of constitutively active replication origins. This strand-biased pattern is conserved, together with centromere position, among related strains and species, in a manner independent of primary DNA sequence. Thus, inheritance of centromere position is correlated with a constitutively active origin of replication that fires at a distinct early time. We suggest a model in which the distinct timing of DNA replication serves as an epigenetic mechanism for the inheritance of centromere position

Partial characterization of dinoflagellate chromosomal proteins

Dinoflagellate chromosomal proteins were analyzed by acrylamide gel electrophoresis. The electrophoretic pattern of acid-insoluble chromosomal proteins from Gyrodinium cohnii in sodium dodecylsulfate gels is less heterogeneous than that of corn, and is characterized by a paucity of bands representing molecular weights below 43 000. Acrylamide gel electrophoresis of G. cohnii and Peridinium trochoideum acid-soluble chromosomal proteins in urea at pH 3.2 gives a banding pattern quite different than that of typical histones. Acid-soluble protein from chromatin prepared by the two different methods and from both organisms migrates as one predominant band with a mobility slightly less than that of Histone IV from corn. Its molecular weight, estimated by sodium dodecylsulfate gel electrophoresis, is about 16000. It is a basic protein (basic/acidic amino acids 1.3) but differs from most histones in that it contains both cysteine and aromatic amino acids and somewhat lower levels of basic amino acids (18 mole % compared with 22 to 30% for histones). In addition, the major acid-soluble component is present in chromatin from log-phase cells but absent in chromatin from stationary-phase cells. For these reasons, the major acid-soluble protein is probably not a histone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22353/1/0000799.pd