Meiotic chromosomes in motion: a perspective from Mus musculus and Caenorhabditis elegans

Vigorous chromosome movement during the extended prophase of the first meiotic division is conserved in most eukaryotes. The movement is crucial for the faithful segregation of homologous chromosomes into daughter cells, and thus for fertility. A prerequisite for meiotic chromosome movement is the stable and functional attachment of telomeres or chromosome ends to the nuclear envelope and their cytoplasmic coupling to the cytoskeletal forces responsible for generating movement. Important advances in understanding the components, mechanisms, and regulation of chromosome end attachment and movement have recently been made. This review focuses on insights gained from experiments into two major metazoan model organisms: the mouse, Mus musculus, and the nematode, Caenorhabditis elegans.

     

Synchrony of Seed Dispersal, Hydrology and Local Climate in a Semi-arid River Reach in California

The temporal availability of propagules is a critical factor in sustaining pioneer riparian tree populations along snowmelt-driven rivers because seedling establishment is strongly linked to seasonal hydrology. River regulation in semi-arid regions threatens to decouple seed development and dispersal from the discharge regime to which they evolved. Using the lower Tuolumne River as a model system, we quantified and modeled propagule availability for Populus fremontii (POFR), Salix gooddingii (SAGO), and Salix exigua (SAEX), the tree and shrub species that dominate near-channel riparian stands in the San Joaquin Basin, CA. A degree-day model was fit to field data of seasonal seed density and local temperature from three sites in 2002–2004 to predict the onset of the peak dispersal period. To evaluate historical synchrony of seed dispersal and seasonal river hydrology, we compared peak spring runoff timing to modeled peak seed release periods for the last 75 years. The peak seed release period began on May 15 for POFR (range April 23–June 10), May 30 for SAGO (range May 19–June 11) and May 31 for SAEX (range May 8–June 30). Degree-day models for the onset of seed release reduced prediction error by 40–67% over day-of-year means; the models predicted best the interannual, versus site-to-site, variation in timing. The historical analysis suggests that POFR seed release coincided with peak runoff in almost all years, whereas SAGO and SAEX dispersal occurred during the spring flood recession. The degree-day modeling approach reduce uncertainty in dispersal timing and shows potential for guiding flow releases on regulated rivers to increase riparian tree recruitment at the lowest water cost.     

Analysis of NVMe over fabrics with SCinet DTN-as-a-Service

Supporting transfers of science big data over Wide Area Networks (WANs) with Data Transfer Nodes (DTNs) requires optimizing multiple parameters within the underlying infrastructure. New solutions for such data movement require new paradigms and technologies, such as NVMe over Fabrics, which provides high-performance data movement with direct remote NVMe device access over traditional fabrics. However, recent NVMe over Fabrics studies have been limited to local storage fabrics. To support increasing demands for the large volume of science data movement during Supercomputing (SC) conferences, we proposed a SCinet DTN-as-a-Service framework orchestrating the desired optimization to meet users, applications, and providers’ requirements. Furthermore, we extend the SCinet DTN-as-a-Service framework to incorporate new techniques, solve optimization issues in data-intensive science and evaluate NVMe over Fabrics with multiple WAN testbeds to examine its performance and discover new opportunities for optimization.

     

Investigating Devonian trees as geo‐engineers of past climates: linking palaeosols to palaeobotany and experimental geobiology

We present the rationale for a cross‐disciplinary investigation addressing the ‘Devonian plant hypothesis’ which proposes that the evolutionary appearance of trees with deep, complex rooting systems represents one of the major biotic feedbacks on geochemical carbon cycling during the Phanerozoic. According to this hypothesis, trees have dramatically enhanced mineral weathering driving an increased flux of Ca²⁺ to the oceans and, ultimately, a 90% decline in atmospheric CO₂ levels through the Palaeozoic. Furthermore, experimental studies indicate a key role for arbuscular mycorrhizal fungi in soil–plant processes and especially in unlocking the limiting nutrient phosphorus in soil via Ca‐phosphate dissolution mineral weathering. This suggests co‐evolution of roots and symbiotic fungi since the Early Devonian could well have triggered positive feedbacks on weathering rates whereby root–fungal P release supports higher biomass forested ecosystems. Long‐standing areas of uncertainty in this paradigm include the following: (1) limited fossil record documenting the origin and timeline of the evolution of tree‐sized plants through the Devonian; and (2) the effects of the evolutionary advance of trees and their in situ rooting structures on palaeosol geochemistry. We are addressing these issues by integrating palaeobotanical studies with geochemical and mineralogical analyses of palaeosol sequences at selected sites across eastern North America with a particular focus on drill cores from Middle Devonian forests in Greene County, New York State.     

What's Inside That Seed We Brew? A New Approach To Mining the Coffee Microbiome

Coffee is a critically important agricultural commodity for many tropical states and is a beverage enjoyed by millions of people worldwide. Recent concerns over the sustainability of coffee production have prompted investigations of the coffee microbiome as a tool to improve crop health and bean quality. This review synthesizes literature informing our knowledge of the coffee microbiome, with an emphasis on applications of fruit- and seed-associated microbes in coffee production and processing. A comprehensive inventory of microbial species cited in association with coffee fruits and seeds is presented as reference tool for researchers investigating coffee-microbe associations. It concludes with a discussion of the approaches and techniques that provide a path forward to improve our understanding of the coffee microbiome and its utility, as a whole and as individual components, to help ensure the future sustainability of coffee production.