Denitrification in Great Basin hot springs

Hydrogen has been proposed to fuel primary production in the Aquificae dominated hot springs of Yellowstone National Park (Spear, et al. 2005), a finding the authors generalized to all hot springs. However, clone libraries derived from Great Basin springs contain few 16S ribosomal RNA (rRNA) gene sequences from Aquificae and many from unknown microorganisms. In the same springs, alternative electron donors rival the reducing power of hydrogen. This project will try to cultivate the uncharacterized microbes of two Great Basin springs and determine which electron donors they can use. Nitrogen is key to life. In its reduced form, ammonia, it is a primary constituent of nucleic acids and proteins. In its oxidized form,nitrate, it frequently substitutes for oxygen in anoxic conditions as microbes’ preferred electron acceptor for respiration. In this capacity, it drives energy capture–typically, though not always, in the process of denitrification [8]. Understanding the supply, demand, and interconversion of nitrogen through an ecosystem is essential to understanding the life within it. Although denitrification has been predicted to occur within hot springs on thermodynamic grounds, and some thermophilic isolates reduce nitrate, denitrification has never been examined in a hot spring. The hot springs of the Great Basin are under studied reservoirs of novel metabolisms and microbes, and are well worth in-depth exploration. Our project adapts techniques regularly used in marine and soil microbiology [6,7,9] to higher temperatures to test our hypothesis: that some thermophiles with in the hot springs respirenitrate, in the process of denitrification, for a significant amount of energy capture

Program schemes with deep pushdown storage.

Inspired by recent work of Meduna on deep pushdown automata, we consider the computational power of a class of basic program schemes, TeX, based around assignments, while-loops and non- deterministic guessing but with access to a deep pushdown stack which, apart from having the usual push and pop instructions, also has deep-push instructions which allow elements to be pushed to stack locations deep within the stack. We syntactically define sub-classes of TeX by restricting the occurrences of pops, pushes and deep-pushes and capture the complexity classes NP and PSPACE. Furthermore, we show that all problems accepted by program schemes of TeX are in EXPTIME

Biogeography and Phylogeny of Aigarchaeota, A Novel Phylum of Archaea

‘Aigarchaeota’ is a candidate phylum of Archaea known only by 16S rRNA gene fragments from cultiva­tion-independent microbial surveys and a single composite genome from Candidatus ‘Caldiarchaeum sub­terraneum’, an inhabitant of a subterranean gold mine in Japan. Gene sequences associated with ‘Aigarchaeo­ta’ have been found in a variety of geothermal habits, however a comprehensive analysis of the phylogeny and distribution of ‘Aigarchaeota’ has not yet been done. Public databases were mined for 16S rRNA gene sequences related to known ‘Aigarchaeota’ and a combination of approaches were used to rigorously define the phylogenetic boundaries of the phylum, investigate its distribution, and design potential ‘Aigarchaeota’- specific primers. Approximately 300 16S rRNA genes and gene fragments affiliated with ‘Aigarchaeota’ were identified, phylogenic analyses suggested that ‘Aigarchaeota’ belonged to at least three family- to order-level groups and at least 13 genus-level groups, and supported the proposed relationship between ‘Aigarchaeota’, Thaumarchaeota, Crenarchaeota, and Korarchaeota in the so-called ‘TACK’ superphylum. A global distri­bution was suggested with genus-level group habitat differentiation. Some groups were predominantly ter­restrial (1A, 2B, 3, 4 & 5) while other groups were mostly found in Marine habitats (6-8). Fifteen strong ‘Ai­garchaeota’-specific primer candidates for the polymerase chain reaction (PCR) amplification of 16S rRNA genes were designed for further analyses

Rebooting Content: Broadcasting Sport and Esports to Homes During COVID-19

Beginning in early March 2020, sport in the United States entered an unprecedented period of hiatus due to the COVID-19 pandemic. The postponement, suspension, and cancellation of live sporting events impacted every professional and amateur sport organization, from the National Basketball Association to the National Association for Stock Car Auto Racing, high school sports to college football, and even esports leagues. Although the abrupt cancellation of live sporting events was disruptive, it did create opportunities for the production of new media and consumption opportunities for sport leagues, teams, and their fans through different types of sport media broadcasts. This commentary examines how the U.S. sport industry developed media content strategies using new, mixed, and rebroadcasted content, across multiple broadcast and streaming platforms, to provide sport consumption opportunities to fans who were largely quarantined at home. This research contributes to the existing scholarship on live and rebroadcasted mediated content, while providing guidance to content owners and rights holders facing uncertainty in the marketplace

Microbial Endemism and Biogeography

The topic of microbial biogeography is almost 100 years old, however, when confronted with questions about the existence and extent of endemism in the microbial world, many microbiologists respond with opinions and theoretical arguments rather than examples of well-conducted studies. We begin this chapter with an overview of this debate as it applies to free-living prokayotes in part because there are relatively few good microbial biogeography studies. Furthermore, the arguments help to frame microbial biogeography in the larger context of biodiversity in that if endemism is common, then many more species exist

Are Incomplete Denitrification Pathways a Common Trait in Thermus Species from Geothermal Springs in China?

Temperature has strong impacts on ecosystem function and biogeochemical cycles, particularly within extreme environments such as geothermal springs above 60 °C. The primary focus of this study was to investigate the denitrification pathways of Thermus (Bacteria) isolates from geothermal springs from Tengchong, China. This study tested the hypothesis that incomplete denitrification is a common characteristic of the genus Thermus, regardless of geographic origin or species affiliation, which would implicate them in the efflux of nitrous oxide (a strong greenhouse gas) to the atmosphere. In this study, we cultivated 25 isolates, including six known Thermus species, and measured the stoichiometry of nitrogenous products of nitrate respiration using gas chromatography and colorimetric assays. We also designed custom primers for polymerase chain reaction (PCR) amplification of denitrification genes including narG, nirS, nirK, and norB to screen for the genetic capacity for each step in denitrification. Experimental results show that all Thermus strains tested display incomplete denitrification pathways terminating at nitrite (NO2 -) or nitrous oxide (N2O), and possibly nitric oxide (NO)

Microbial Nitrogen cycling in Nevada Geothermal Springs

Hot spring habitats above maximum photosynthetic temperature (73 ºC) are not well understood with respect to nitrogen (N) cycling. Few predictions have been made, and even fewer measurements of in situ activities have been reported. Thermodynamic calculations based on in situ chemical and temperature measurements will be used to predict the occurrence of the specific N-cycling reactions. In addition, these measurements in two springs will aid in an attempt to cultivate ammonia oxidizing species

On Factor Universality in Symbolic Spaces

The study of factoring relations between subshifts or cellular automata is central in symbolic dynamics. Besides, a notion of intrinsic universality for cellular automata based on an operation of rescaling is receiving more and more attention in the literature. In this paper, we propose to study the factoring relation up to rescalings, and ask for the existence of universal objects for that simulation relation. In classical simulations of a system S by a system T, the simulation takes place on a specific subset of configurations of T depending on S (this is the case for intrinsic universality). Our setting, however, asks for every configurations of T to have a meaningful interpretation in S. Despite this strong requirement, we show that there exists a cellular automaton able to simulate any other in a large class containing arbitrarily complex ones. We also consider the case of subshifts and, using arguments from recursion theory, we give negative results about the existence of universal objects in some classes

Compact, Deep-Penetrating Geothermal Heat Flow Instrumentation for Lunar Landers

Geothermal heat flow is obtained as a product of the two separate measurements of geothermal gradient in, and thermal conductivity of, the vertical soi/rock/regolith interval penetrated by the instrument. Heat flow measurements are a high priority for the geophysical network missions to the Moon recommended by the latest Decadal Survey [I] and previously the International Lunar Network [2]. The two lunar-landing missions planned later this decade by JAXA [3] and ESA [4] also consider geothermal measurements a priority

Cellular automata and Lyapunov exponents

In this article we give a new definition of some analog of Lyapunov exponents for cellular automata . Then for a shift ergodic and cellular automaton invariant probability measure we establish an inequality between the entropy of the automaton, the entropy of the shift and the Lyapunov exponent