The diversity and interactions of fungi from the Paleozoic and Mesozoic of Antarctica

Fungi are ubiquitous in all ecosystems and are the driving force in many types of interactions, such as mutualists, saprotrophs, parasites, and necrotrophs. Fungi are equally as integral in extant ecosystems as they certainly were in paleoecosystems. Paleomycology, the study of fossil fungi, is an emerging field of paleontology. Most fossil fungi are found in or in close association with plants and thus, paleomycology is also considered a sub-discipline of paleobotany. Therefore when plants are well preserved there is the increase potential to examine their fungal associates. Permineralized material is a preservation type that offers the opportunity to study plants, fungi, and other microorganisms anatomically and morphologically. Prior research suggested that fungi were too fragile and delicate to be structurally preserved in the fossil record; however, fungi have been described in some early paleobotanical studies as dispersed fragments, spores, and other remnants. The taxonomic and ecological affinities of many of these fungi, however, were not described in great detail. The objective of this study is to investigate the fungal components and plant-fungal associations of the Permian, Triassic, and Jurassic of Antarctica. The Paleobotanical Collections at the University of Kansas (KU) house the largest collection of Antarctic permineralized peat deposits in the world. To date, the majority of reports on Antarctic fossil fungi are found in Triassic peat material, with fewer reports on Permian fungi, and are most sparse on Jurassic fungi. These contributions utilized the acetate peel technique, a traditional method of studying permineralized material in paleobotany, and provided a platform for the investigation of microorganisms in ancient Antarctic environments. It has been demonstrated that paleontological thin sections of permineralized peat yields more information on fossil microbes because the fine details of the microorganisms are not etched away as they would be in the acetate peel technique. This study will fully exploit the use of paleontological thin section techniques, as well as preliminary studies using analytical techniques, to discover and describe new fossil fungi and plant-fungal interactions from the Antarctic paleobotanical collections at KU. Despite the large number of fungal remains in the fossil record, including those that provide direct or indirect evidence of an association or interaction with land plants, the discipline of paleomycology is at a relatively early stage of development. As more information is obtained about fossil fungi, including those from Antarctic permineralized peat deports, it will be increasingly possible to present more detailed hypotheses that can be used in association with those described from modern communities, to more accurately depict the role of these organisms in the functioning of early continental ecosystems. Therefore, this study adds new information to our understanding of the diversity of fungi in the Permian, Triassic, and Jurassic of Antarctica, and thus contributes to a more focused concept of the complexity of late Paleozoic and Mesozoic ecosystems

What is the best age to start vitamin D supplementation to prevent rickets in breastfed newborns?

Evidence-based answer: It's unclear what age is best to start vitamin D supplementation because no comparison studies exist. That said, breastfed infants who take vitamin D beginning at 3 to 5 days of life don't develop rickets (strength of recommendation SOR]: B, randomized trial). Starting infants on vitamin D supplementation at one to 36 months of age reduces the risk of rickets (SOR: B, a controlled and a randomized controlled trial)

Preservice Elementary Teachers’ Beliefs about the Role of Definition in the Learning of Mathematics

Answering a call to emphasize the act of defining over the learning of definitions, we have shifted the content of a geometry course for preservice elementary teachers (PSETs) away from comparing and applying pre-written classification structures to classroom episodes centered on authoring definitions for special quadrilaterals. PSETs complete activities using geometry software, and collaboratively create definitions for specific quadrilaterals. In order to fully understand the potential of this curricular shift, we asked preservice elementary mathematics teachers’ to share their perceptions of the process of writing mathematical definitions. Data from participant reflections were analyzed for themes related to mathematical definition and the act of defining. The framework that resulted from iterative discussions by the researchers examined beliefs about the nature of definition and mathematical empathy (Araki, 2015). Findings also suggest that beliefs about authority and positioning students as authors of mathematics are associated with mathematical empathy. Experiences related to the process of defining enabled PSETs to see far greater subjectivity in the discipline of mathematics and to consider, perhaps for the first time, that they, too, were both able and deserving of becoming authors of mathematical ideas

Filamentous cyanobacteria preserved in masses of fungal hyphae from the Triassic of Antarctica

This work is licensed under a Creative Commons Attribution 4.0 International License.Permineralized peat from the central Transantarctic Mountains of Antarctica has provided a wealth of information on plant and fungal diversity in Middle Triassic high-latitude forest paleoecosystems; however, there are no reports as yet of algae or cyanobacteria. The first record of a fossil filamentous cyanobacterium in this peat consists of wide, uniseriate trichomes composed of discoid cells up to 25 µm wide, and enveloped in a distinct sheath. Filament morphology, structurally preserved by permineralization and mineral replacement, corresponds to the fossil genus Palaeo-lyngbya, a predominantly Precambrian equivalent of the extant Lyngbya sensu lato (Oscillatoriaceae, Oscillatoriales). Specimens occur exclusively in masses of interwoven hyphae produced by the fungus Endochaetophora antarctica, suggesting that a special micro-environmental setting was required to preserve the filaments. Whether some form of symbiotic relationship existed between the fungus and cyanobacterium remains unknown

Attitudes Concerning Nutrition Education in Associate Degree Nursing Programs

Food, Nutrition and Institution Administratio

Biochemical Kinetics Model of DSB Repair and GammaH2AX FOCI by Non-homologous End Joining

We developed a biochemical kinetics approach to describe the repair of double strand breaks (DSB) produced by low LET radiation by modeling molecular events associated with the mechanisms of non-homologous end-joining (NHEJ). A system of coupled non-linear ordinary differential equations describes the induction of DSB and activation pathways for major NHEJ components including Ku(sub 70/80), DNA-PK(sub cs), and the Ligase IV-XRCC4 hetero-dimer. The autophosphorylation of DNA-PK(sub cs and subsequent induction of gamma-H2AX foci observed after ionizing radiation exposure were modeled. A two-step model of DNA-PK(sub cs) regulation of repair was developed with the initial step allowing access of other NHEJ components to breaks, and a second step limiting access to Ligase IV-XRCC4. Our model assumes that the transition from the first to second-step depends on DSB complexity, with a much slower-rate for complex DSB. The model faithfully reproduced several experimental data sets, including DSB rejoining as measured by pulsed-field electrophoresis (PFGE), quantification of the induction of gamma-H2AX foci, and live cell imaging of the induction of Ku(sub 70/80). Predictions are made for the behaviors of NHEJ components at low doses and dose-rates, where a steady-state is found at dose-rates of 0.1 Gy/hr or lower