Biosensor-based engineering of biosynthetic pathways

Biosynthetic pathways provide an enzymatic route from inexpensive renewable resources to valuable metabolic products such as pharmaceuticals and plastics. Designing these pathways is challenging due to the complexities of biology. Advances in the design and construction of genetic variants has enabled billions of cells, each possessing a slightly different metabolic design, to be rapidly generated. However, our ability to measure the quality of these designs lags by several orders of magnitude. Recent research has enabled cells to report their own success in chemical production through the use of genetically encoded biosensors. A new engineering discipline is emerging around the creation and application of biosensors. Biosensors, implemented in selections and screens to identify productive cells, are paving the way for a new era of biotechnological progress

Motorized Beam Alignment of a Commercial X-ray Diffractometer

X-ray diffraction (XRD) is a powerful analysis method that allows researchers to noninvasively probe the crystalline structure of a material. This includes the ability to determine the crystalline phases present, quantify surface residual stresses, and measure the distribution of crystallographic orientations. The Structures and Materials Division at the NASA Glenn Research Center (GRC) heavily uses the on-site XRD lab to characterize advanced metal alloys, ceramics, and polymers. One of the x-ray diffractometers in the XRD lab (Bruker D8 Discover) uses three different x-ray tubes (Cu, Cr, and Mn) for optimal performance over numerous material types and various experimental techniques. This requires that the tubes be switched out and aligned between experiments. This alignment maximizes the x-ray tube s output through an iterative process involving four set screws. However, the output of the x-ray tube cannot be monitored during the adjustment process due to standard radiation safety engineering controls that prevent exposure to the x-ray beam when the diffractometer doors are open. Therefore, the adjustment process is a very tedious series of blind adjustments, each followed by measurement of the output beam using a PIN diode after the enclosure doors are shut. This process can take up to 4 hr to perform. This technical memorandum documents an in-house project to motorize this alignment process. Unlike a human, motors are not harmed by x-ray radiation of the energy range used in this instrument. Therefore, using motors to adjust the set screws will allow the researcher to monitor the x-ray tube s output while making interactive adjustments from outside the diffractometer. The motorized alignment system consists of four motors, a motor controller, and a hand-held user interface module. Our goal was to reduce the alignment time to less than 30 min. The time available was the 10-week span of the Lewis' Educational and Research Collaborative Internship Project (LERCIP) summer internship program and the budget goal was $1200. In this report, we will describe our motorization design and discuss the results of its implementation

Effects of Biochar on Soil Fertility and Crop Yields: Experience from the Southern Highlands of Tanzania

The world’s agricultural production is declining due to severe loss of soil fertility through natural processes or because of human activities. Biochar has been identified as a potential soil amendment to regain its fertility and increase crop productivity. This study aimed to assess the effects of biochar on soil nutrients and crop yields in the southern highlands of Tanzania. Data were collected through key informant and household interviews, and from sampling of soils in coffee farms where biochar of maize cobs origin was incorporated at the rate of 3 t ha-1. Purposive sampling approach was deployed to identify the villages in which farmers have been incorporating biochar in farms. A total of 172 households, 30 key informants, and 12 top and subsoil samples were involved in this study. Quantitative data were analyzed using SPSS version 20, and excel spreadsheet was used for descriptive results and relationships. The findings revealed that biochar significantly increased soil pH, iron (Fe), organic carbon (OC), cation exchange capacity (CEC) and exchangeable bases (potassium-K, magnesium-Mg). T - tests showed significant increase of soil nutrients in biochar treated soils. In addition, biochar increased coffee and maize yields from 1 t ha-1 to 3 t ha-1. Keywords: Biochar; Soil Nutrients; Food Security; Resilience; Adaptatio

Coping During the Time of Covid: Mental Health and Changes in Religious Practices

While rituals, particularly religious rituals, have long been the focus of anthropological research, they have only recently become a focus of psychological research. Ritual is defined as 1) predefined sequences of behavior characterized by rigidity, formality, and repetition that are 2) causally opaque, and 3) embedded in a larger system of symbolism and meaning (Hobson et al., 2017; Lawson & McCauley, 1990; Wen et al., 2020). Religious rituals appear to provide three primary regulatory functions for individuals: regulation of emotions, of the performance of goal states, and of social connections (Hobson, et al., 2017). Because of the importance of ritual in emotion regulation, one would expect 1) experiencing an emotional deficit should elicit more ritualistic behavior and 2) enacting rituals should thereby reduce emotional deficits (Hobson, et al., 2017). The current study compared self-reports of anxiety and depression before and during the Covid pandemic with type, frequency, and importance of religious ritual participation. It was hypothesized that, for those for whom religious rituals were an important facet of life, ritual participation would be negatively related to levels of anxiety and depression during the pandemic. Surveys were completed by 122 students at a small, Midwestern liberal arts university. The results indicate that while participation in personal religious behavior such as private prayer and scripture reading did not change during the pandemic, participation in scripted religious rituals did decrease slightly. Both before and during the pandemic individuals rated personal devotional practices such as prayer and scripture reading as more important than participation in personal or corporate religious rituals. Inconsistent with previous research, there was not a relationship between religious belief and behavior with mental health outcomes such as anxiety and depression. Most people who reported an increase in anxiety and depression during the pandemic indicated that at least part of the reason for the increase was their inability to worship in person with others. However, overall depression and anxiety scores were not related to reported increases or decreases in religious ritual participation during the pandemic. Conversely, for those reporting that their anxiety and depression increased at least partly due to the inability to worship publicly with others, changes in depression and anxiety scores were inversely related to continued ritual practices during the pandemic, supporting the hypotheses of this study. Overall, these data indicate a complex relationship among religious ritual participation, personal devotional practices, and mental health outcomes

Constraining Prebiotic Chemistry Through a Better Understanding of Earth's Earliest Environments

Any search for present or past life beyond Earth should consider the initial processes and related environmental controls that might have led to its start. As on Earth, such an understanding lies well beyond how simple organic molecules become the more complex biomolecules of life, because it must also include the key environmental factors that permitted, modulated, and most critically facilitated the prebiotic pathways to life's emergence. Moreover, we ask how habitability, defined in part by the presence of liquid water, was sustained so that life could persist and evolve to the point of shaping its own environment. Researchers have successfully explored many chapters of Earth's coevolving environments and biosphere spanning the last few billion years through lenses of sophisticated analytical and computational techniques, and the findings have profoundly impacted the search for life beyond Earth. Yet life's very beginnings during the first hundreds of millions of years of our planet's history remain largely unknown--despite decades of research. This report centers on one key point: that the earliest steps on the path to life's emergence on Earth were tied intimately to the evolving chemical and physical conditions of our earliest environments. Yet, a rigorous, interdisciplinary understanding of that relationship has not been explored adequately and once better understood will inform our search for life beyond Earth. In this way, studies of the emergence of life must become a truly interdisciplinary effort, requiring a mix that expands the traditional platform of prebiotic chemistry to include geochemists, atmospheric chemists, geologists and geophysicists, astronomers, mission scientists and engineers, and astrobiologists.Comment: Planetary science and astrobiology community white paper submitted to the National Academy of Science

HST UV Spectroscopy of the Dwarf Starburst Galaxy Pox 186

Studying the galaxies responsible for reionization is often conducted through local reionization-era analogs; however, many of these local analogs are too massive to be representative of the low-mass star-forming galaxies that are thought to play a dominant role in reionization. The local, low-mass dwarf starburst galaxy Pox 186 is one such system with physical conditions representative of a reionization-era starburst galaxy. We present deep ultraviolet (UV) spectroscopy of Pox 186 to study its stellar population and ionization conditions and to compare these conditions to other local starburst galaxies. The new Cosmic Origins Spectrograph data are combined with archival observations to cover $\sim$1150-2000 A and allow for an assessment of Pox 186's stellar population, the relative enrichment of C and O, and the escape of ionizing photons. We detect significant Ly$\alpha$ and low-ionization state absorption features, indicative of previously undetected neutral gas in Pox 186. The C/O relative abundance, log(C/O) = -0.62$\pm$0.02, is consistent with other low-metallicity dwarf galaxies and suggests a comparable star formation history in these systems. We compare UV line ratios in Pox 186 to those of dwarf galaxies and photoionization models, and we find excellent agreement for the ratios utilizing the intense C III], O III], and double-peaked C IV lines. However, the UV and optical He II emission is faint and distinguishes Pox 186 from other local starburst dwarf galaxies. We explore mechanisms that could produce faint He II, which have implications for the low-mass reionization-era galaxies which may have similar ionization conditions.Comment: 22 pages, 9 figures, accepted for publication in The Astrophysical Journa

tRNAs: Cellular Barcodes for Amino Acids

The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl‐tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond translation, which together suggest that the role of tRNA is to deliver amino acids for a variety of processes that includes, but is not limited to, protein synthesis

A First Look at the Abundance Pattern -- O/H, C/O, Ne/O, and Fe/O -- in z>7z>7 Galaxies with JWST/NIRSpec

We analyze the rest-frame near-UV and optical nebular spectra of three z > 7 galaxies from the Early Release Observations taken with the Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST). These three high-z galaxies show the detection of several strong-emission nebular lines, including the temperature-sensitive [O III] $\lambda$4363 line, allowing us to directly determine the nebular conditions and gas-phase abundances for O/H, C/O, Ne/O, and Fe/O. We derive O/H abundances and ionization parameters that are generally consistent with other recent analyses. The lowest-mass galaxy has a large O/H uncertainty, which as a significant effect on anchoring the mass-metallicity relationship (i.e., slope) and tests of its redshift evolution. We also detect the C III] $\lambda$$\lambda$1907,1909 emission in a z > 8 galaxy from which we determine the most distant C/O abundance to date. This valuable detection provides the first test of C/O redshift evolution out to high-redshift. For neon, we use the high-ionization [Ne III] $\lambda$3869 line to measure the first Ne/O abundances at z>7, finding no evolution in this $\alpha$-element ratio. To investigate the Fe abundance, we explore the tentative detection of weak [Fe II] and [Fe III] lines in a z>8 galaxy, which would indicate a rapid build up of metals. Importantly, we demonstrate that properly flux-calibrated and higher S/N spectra are crucial to robustly determine the abundance pattern in z>7 galaxies with NIRSpec/JWST.Comment: Submitted to The Astrophysical Journal Letters. Comments welcom