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Insights from novel mechanistic paradigms in gene expression control have led to the development of new gene expression systems for bioproduction, control, and sensing applications. Coupled with a greater understanding of synthetic burden and modern creative biodesign approaches, contemporary bacterial gene expression tools and systems are emerging that permit fine-tuning of expression, enabling greater predictability and maximisation of specific productivity, while minimising deleterious effects upon cell viability. These advances have been achieved by using a plethora of regulatory tools, operating at all levels of the so-called ‘central dogma’ of molecular biology. In this review, we discuss these gene regulation tools in the context of their design, prototyping, integration into expression systems, and biotechnological application. A huge array of genetic regulatory tools are now available that permit gene expression control at all layers of the central dogma.Matching production demand with cellular capacity can reduce burden and allow stable production over longer timescales.Modern in silico design tools allow rapid design and optimisation of complex genetic circuitry.Cell-free prototyping of genetic parts and devices is an emerging, yet powerful tool to improve the design–build–test–learn cycle.The use of feedback loops to facilitate dynamic regulation of gene expression allows researchers to construct responsive pathways to minimise cellular metabolic burden.Stress-linked expression regulation enables coupling of heterologous production with endogenous stress response pathways.

Public health policies designed to influence individuals' infection-control behaviour are a tool for governments to help prevent the spread of disease. Findings on the impacts of policies are mixed and there is limited information on the effects of removing restrictions and how policies impact behavioural trends. We use low-acuity emergency department visits from 12 hospitals in New Brunswick, Canada, (January 2017 -October 2021) as a proxy for infection-control behaviour and provide insight into the effects of the COVID-19 virus on a population with a low prevalence of cases. Quasi-experimental techniques (event studies) are applied to estimate the magnitude and persistence of effects of specific events (e.g., policy changes), to control for COVID-19 cases and vaccines, and to explore how the effectiveness of policy changes during the pandemic as more policies are introduced. Initial tightening of restrictions on March 11, 2020 reduced low-acuity emergency department visits by around 60% and reached a minimum after 30 days. Relaxing policies on social gatherings and personal services gradually increased low-acuity emergency department visits by approximately 50% after 44 days. No effects were found from policies lifting all restrictions, and reinstating a state of emergency on July 31, 2021, and September 24, 2021. These results suggest that policy interventions are less likely to be effective at influencing infection control behaviour with time and more policies introduced, and that tracking and publicly reporting case numbers can influence infection control behaviour.

The distribution of heat-producing elements (HPE) potassium (K), uranium (U), and thorium (Th) within planetary interiors has major implications for the thermal evolution of the terrestrial planets and for the inventory of volatile elements in the inner solar system. To investigate the abundances of HPE in Mercury's interior, we conducted experiments at high pressure and temperature (up to 5 GPa and 1900 °C) and reduced conditions (IW-1.8 to IW-6.5) to determine U, Th, and K partitioning between metal, silicate, and sulfide (Dmet/sil and Dsulf/sil). Our experimental data combined with those from the literature show that partitioning into sulfide is more efficient than into metal and that partitioning is enhanced with decreasing FeO and increasing O contents of the silicate and sulfide melts, respectively. Also, at low oxygen fugacity (log fO2 < IW-5), U and Th are more efficiently partitioned into liquid iron metal and sulfide than K. Dmet/sil for U, Th, and K increases with decreasing oxygen fugacity, while DUmet/sil and DKmet/sil increase when the metal is enriched and depleted in O or Si, respectively. We also used available data from the literature to constrain the concentrations of light elements (Si, S, O, and C) in Fe metal and sulfide. We calculated chemical compositions of Mercury's core after core segregation, for a range of fO2 conditions during its differentiation. For example, if Mercury differentiated at IW-5.5, its core would contain 49 wt% Si, 0.02 wt% S, and negligible C. Also if core-mantle separation happened at a fO2 lower than IW-4, the bulk Mercury Fe/Si ratio is likely to be chondritic. We calculated concentrations of U, Th, and K in the Fe-rich core and possible sulfide layer of Mercury. Bulk Mercury K/U and K/Th were calculated taking all U, Th, and K reservoirs into account. Without any sulfide layer, or if Mercury's core segregated at a higher fO2 than IW-4, bulk K/U and K/Th would be similar to those measured on the surface, confirming more elevated volatile K concentration than previously expected for Mercury. However, Mercury could fall on an overall volatile depletion trend where K/U increases with the heliocentric distance if core segregation occurred near IW-5.5 or more reduced conditions, and with a sulfide layer of at least 130 km thickness. At these conditions, the bulk Mercury K/Th ratio is close to Venus's and Earth's values. Since U and Th become more chalcophile with decreasing oxygen fugacity, to a higher extent than K, it is likely that at an fO2 close to, or lower than, IW-6 both K/U and K/Th become lower than values of the other terrestrial planets. Therefore, our results suggest that the elevated K/U and K/Th ratios of Mercury's surface should not be exclusively interpreted as the result of a volatile enrichment in Mercury, but could also indicate a sequestration of more U and Th than K in a hidden iron sulfide reservoir, possibly a layer present between the mantle and core. Hence, Mercury could be more depleted in volatiles than Mars with a K concentration similar to or lower than the Earth's and Venus's, suggesting volatile depletion in the inner solar system. In addition, we show that the presence of a sulfide layer formed between IW-4 and IW-5.5 decreases the total radioactive heat production of Mercury by up to 30%.

The lunar surface, a key proxy for the early Earth, contains relics of asteroids and comets that have pummeled terrestrial planetary surfaces. Surviving fragments of projectiles in the lunar regolith provide a direct measure of the types and thus the sources of exogenous material delivered to the Earth-Moon system. In ancient [> 3.4 billion years ago (Ga)] regolith breccias from the Apollo 16 landing site, we located mineral and lithologie relics of magnesian chondrules from chondritic impactors. These ancient impactor fragments are not nearly as diverse as those found in younger (3.4 Ga to today) regolith breccias and soils from the Moon or that presently fall as meteorites to Earth. This suggests that primitive chondritic asteroids, originating from a similar source region, were common Earth-Moon-crossing impactors during the latter stages of the basin-forming epoch.

Background The secretion of recombinant disulfide-bond containing proteins into the periplasm of Gram-negative bacterial hosts, such as E. coli, has many advantages that can facilitate product isolation, quality and activity. However, the secretion machinery of E. coli has a limited capacity and can become overloaded, leading to cytoplasmic retention of product; which can negatively impact cell viability and biomass accumulation. Fine control over recombinant gene expression offers the potential to avoid this overload by matching expression levels to the host secretion capacity. Results Here we report the application of the RiboTite gene expression control system to achieve this by finely controlling cellular expression levels. The level of control afforded by this system allows cell viability to be maintained, permitting production of high-quality, active product with enhanced volumetric titres. Conclusions The methods and systems reported expand the tools available for the production of disulfide-bond containing proteins, including antibody fragments, in bacterial hosts.

The oceanic core complex comprising Atlantis Massif was formed within the past 1.5-2 Myr at the intersection of the Mid-Atlantic Ridge, 30°N, and the Atlantis Transform Fault. The corrugated, striated central dome prominently displays morphologic and geophysical characteristics representative of an ultramafic core complex exposed via long-lived detachment faulting. Sparse volcanic features on the massif's central dome indicate that minor volcanics have penetrated the inferred footwall, which geophysical data indicates is composed predominantly of variably serpentinized peridotite. In contrast, the hanging wall to the east of the central dome is comprised of volcanic rock. The southern part of the massif has experienced the greatest uplift, shoaling to less than 700 m below sea level, and the coarsely striated surface there extends eastward to the top of the median valley wall. Steep landslide embayments along the south face of the massif expose cross sections through the core complex. Almost all of the submersible and dredge samples from this area are deformed, altered peridotite and lesser gabbro. Intense serpentinization within the south wall has likely contributed to the uplift of the southern ridge and promoted the development of the Lost City Hydrothermal Field near the summit. Differences in the distribution with depth of brittle deformation observed in microstructural analyses of outcrop samples suggest that low-temperature strain, such as would be associated with a major detachment fault, is concentrated within several tens of meters of the domal surface. However, submersible and camera imagery show that deformation is widespread along the southern face of the massif, indicating that a series of faults, rather than a single detachment, accommodated the uplift and evolution of this oceanic core complex.[PUBLICATION ABSTRACT]

Household food insecurity is associated with both low income and high cost of living, it is a potentially better measure for consumption compared to income. We use data on food insecurity and income from 10 years of the Canadian Community Health Survey (2007–2017) of single-person households (n = 145,044) to estimate the probability of being food insecure at the Canadian poverty thresholds (Market Basket Measure thresholds, or MBMs), and determine the income required to reach that probability in each MBM region, aggregated by province and rural/urban status. A regression model shows the probability of being food insecure at the MBM is approximately 30% which we call the Food Insecurity Poverty Line (FIPL). The income required to meet the FIPL is substantially different from the MBM, sometimes 1.25 times the MBM. This implies that food insecurity is a potential sentinel measure for poverty.

This dissertation analyzes the trope of the Amazonian shaman in recent Latin American literature and film. References to shamanism have become increasingly popular in recent years. Shamans have gained importance in environmentalism and struggles for Indigenous rights, as well as academic writing interested in radical social change. Meanwhile, shamanic tourism attracts thousands to the Amazon region each year. The books and films of this dissertation participate in this trend by mobilizing the shaman as a figure that holds privileged solutions to contemporary problems like ecological decline, climate change, and persistent coloniality. I argue that these shamanic solutions are often superficial and aimed at satisfying Western desires for progress and limitless growth. Furthermore, they reproduce problematic colonialist tropes, including Western fascination with the ‘wild man.’ Nevertheless, my readings also show how these works may suggest possibilities for change. I draw on critical environmental scholarship, including the work of Elizabeth Povinelli, Stacy Alaimo, Déborah Danowski and Eduardo Viveiros de Castro to show how the shaman characters’ risk-laden and grounded negotiations with materiality may sometimes challenge anthropocentrism and narratives of progress. Moreover, through their frequent references to the Amazonian archive of colonial texts, anthropology, literature and film, the works themselves model a similar process of negotiation that transforms the notion of shamanism. My own contribution via this dissertation is also an inevitable part of this ongoing engagement. Chapter 1 analyzes the influence of shamanic ayahuasca tourism and desires for reconciliation with Indigenous peoples over the abuses of colonialism in the film El abrazo de la serpiente (2015). Chapter 2 addresses how the film Ícaros: A Vision (2016) undermines the drama of shamanic miracle healing and tourism through a focus on the characters’ imbrication with materiality. Chapter 3 compares the ambivalence of shamanic pharmakon remedies in the novels Todas as coisas são pequenas (2008) and El último guerrero de’Aruwa (2006), and the film Chamán: El último guerrero (2016). Chapter 4 analyzes shaman Davi Kopenawa’s techniques for maneuvering restrictions on Indigenous discourse in The Falling Sky: Words of a Yanomami Shaman (2010).

Our ability to regulate the transmission of information from genotype to phenotype underpins the field of synthetic biology. The inducible production of heterologous protein is a powerful tool for the construction of a variety of applications, including biosensing, bioprocessing and foundational research. However, the tools currently available are often limited due to challenges with high levels of basal protein expression, context dependencies, poor orthogonality and limited dynamic range. This study investigates methods for improving the performance of inducible protein production tools that regulate transcription or translation initiation. Through the application of directed evolution, rational design and statistical modelling methods, including Partial Least Squares and Design of Experiments, the modularity and performance of several gene expression tools were significantly improved. The tools engineered in this body of work include cis-repressed translation activating riboswitches and a protocatechuic acid inducible, allosteric transcription factor based biosensor. We present methods and approaches to understand context dependence, isolate riboswitch insulators and improve the maximal expression and dynamic range of these regulatory tools. These methods facilitate the robust and efficient discovery of device topologies with enhanced function and robustness. By using statistical, rather than mechanistic, modelling we are able to achieve significant gain of function in the absence of thorough part characterisation or complex structural analysis; demonstrating the power of objective reasoning for the optimisation of complex, multidimensional biological systems.