37 research outputs found

    Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

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    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes.ImportanceDecades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS) species, we demonstrate that fungi can mediate the ecological distributions of closely related bacterial species. One of the Staphylococcus species studied, S. saprophyticus, is a common cause of urinary tract infections. By identifying processes that control the abundance of undesirable CNS species, cheese producers will have more precise control on the safety and quality of their products. More generally, Staphylococcus species frequently co-occur with fungi in mammalian microbiomes, and similar bacterium-fungus interactions may structure bacterial diversity in these systems

    Pragmatic financialisation: the role of the Japanese Post Office

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    The Japanese Post Office, one of the world’s largest financial institutions, was finally privatised in 2015, marking an appropriate time to examine financialisation in Japan. Literature on financialisation and changes in Japanese capitalism assumes convergence on Anglo-American capitalism with a diminishing of state power. The main argument of this paper is that financialisation is instead a more contingent process. This is put forth through an examination of how this process has been mediated by the Japanese state through the workings of the Japanese Post Office. The state has frequently shaped the direction of financialisation by intervening in the routing of household funds via the postal savings system in order to achieve its objectives in different circumstances, particularly evident in the protracted and contested nature of the post bank’s privatisation. Financialisation is thus not preordained; instead its path is hewn by crisis, catastrophe, demographics and the agency of domestic social actors

    Wind pressure loading cycles for wall cladding during hurricanes

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    A wind pressure loading cycle has been developed that aims to simulate the fluctuating wind loads experienced by wall cladding during the passage of a hurricane. Hour long wind pressure records from the Texas Tech University (TTU) Wind Engineering Research Field Laboratory (WERFL) have been used to derive the loading cycle

    Basic statistical methods

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    Biotic Interactions Shape the Ecological Distributions of Staphylococcus

    No full text
    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ. Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes
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