Stem–loop binding protein expressed in growing oocytes is required for accumulation of mRNAs encoding histones H3 and H4 and for early embryonic development in the mouse

AbstractGrowing oocytes accumulate mRNAs and proteins that support early embryogenesis. Among the most abundant of these maternal factors are the histones. Histone mRNA accumulation and translation are mainly restricted to S-phase in somatic cells, and the mechanism by which oocytes produce histones is unknown. In somatic cells, replication-dependent histone synthesis requires the stem–loop binding protein (SLBP). SLBP is expressed during S-phase, binds to the 3′-untranslated region of non-polyadenylated transcripts encoding the histones, and is required for their stabilization and translation. SLBP is expressed in oocytes of several species, suggesting a role in histone synthesis. To test this, we generated transgenic mice whose oocytes lack SLBP. mRNAs encoding histones H3 and H4 failed to accumulate in these oocytes. Unexpectedly, mRNAs encoding H2A and H2B were little affected. Embryos derived from SLBP-depleted oocytes reached the 2-cell stage, but most then became arrested. Histones H3 and H4, but not H2A or H2B, were substantially reduced in these embryos. The embryos also expressed high levels of γH2A.X. Injection of histones into SLBP-depleted embryos rescued them from developmental arrest. Thus, SLBP is an essential component of the mechanism by which growing oocytes of the mouse accumulate the histones that support early embryonic development

Bioreactor scale induced alteration in cell metabolic state can impact amino acid misincorporations in recombinant proteins produced in CHO cells

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The Hydration Status of Female Collegiate Soccer Players Over Consecutive Training and Match Days

Purpose: Hydration has been shown to play a pivotal role in sport. Soccer is a team sport in which the integrity of all players is vital for team performance; thus, individual player hydration status is important. The primary aim of this study was to investigate the hydration status of female collegiate soccer players during regular season. Methods: Sixteen collegiate female soccer players (age: 20.4 ± 0.8 years; height: 163.6 ± 6.9 cm; weight: 65.3 ± 12 kg) provided urine over 9 days to monitor their hydration status. Hydration was determined by urine specific gravity (Usg). Usg was analyzed in the morning (AM) and in the afternoon before practice/game (PM). Results: All 16 players were at least minimally hypohydrated (Usg \u3e 1.010) in the AM on 5 of the 9 days tested. Players had significantly higher Usg values in the AM as compared to PM (F(1,250) = 23.09; p \u3c 0.0001); however, there was no significant time*day interaction (F(1,250) = 1.98; p = 0.16). Conclusion: Data show a high prevalence of hypohydration occurring in this specific population. This sub-optimal hydration status could be a cause for concern in terms of overall performance. Efforts should be made to integrate hydration interventions and daily monitoring to minimize hypohydration in players

The Hydration Status of Female Collegiate Soccer Players Over Consecutive Training and Match Days

Purpose: Hydration has been shown to play a pivotal role in sport. Soccer is a team sport in which the integrity of all players is vital for team performance; thus, individual player hydration status is important. The primary aim of this study was to investigate the hydration status of female collegiate soccer players during regular season. Methods: Sixteen collegiate female soccer players (age: 20.4 ± 0.8 years; height: 163.6 ± 6.9 cm; weight: 65.3 ± 12 kg) provided urine over 9 days to monitor their hydration status. Hydration was determined by urine specific gravity (Usg). Usg was analyzed in the morning (AM) and in the afternoon before practice/game (PM). Results: All 16 players were at least minimally hypohydrated (Usg \u3e 1.010) in the AM on 5 of the 9 days tested. Players had significantly higher Usg values in the AM as compared to PM (F(1,250) = 23.09; p \u3c 0.0001); however, there was no significant time*day interaction (F(1,250) = 1.98; p = 0.16). Conclusion: Data show a high prevalence of hypohydration occurring in this specific population. This sub-optimal hydration status could be a cause for concern in terms of overall performance. Efforts should be made to integrate hydration interventions and daily monitoring to minimize hypohydration in players

CAPSTONE: Recovery & Operations of a Tumbling Small Satellite in Deep Space

The Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) satellite, deployed in July 2022, experienced a thruster anomaly in September 2022 during its Ballistic Lunar Transfer (BLT) into the Earth-Moon L2 Near Rectilinear Halo Orbit (NRHO). CAPSTONE\u27s primary mission objective to achieve and maintain NRHO serves to validate the cislunar CONOPS contemplated for NASA\u27s Lunar Gateway. Terran Orbital designed and built CAPSTONE, and serves as the operator of the on-orbit spacecraft. Advanced Space owns and operates the CAPSTONE payload and its software on behalf of NASA, as well as performs mission navigation and maneuver design. This 12U+ lunar nanosatellite contains a pump-fed hydrazine propulsion system from Stellar Exploration, enabling all orbital maneuvers and momentum management for the mission. The CAPSTONE mission is funded by the NASA Space Technology Mission Directorate (STMD) through the Small Spacecraft Technology program, and by the Human Exploration and Operations Mission Directorate (HEOMD) through the Advanced Exploration Systems program. This paper will examine the timeline, innovation, and steps taken by the spacecraft team to recover the vehicle from the thruster anomaly and the resulting high-rate tumble. The high-rate tumble was induced by a valve which became stuck open at the conclusion of Trajectory Correction Maneuver 3 (TCM-3). The timeline discussion includes initial autonomous fault recovery, the evolution of the state of the vehicle, and the recovery actions taken by a small, agile engineering team. The off-nominal attitude and thermal state was determined from a limited data set, requiring the largest assets in NASA\u27s Deep Space Network (DSN) to support communications with the vehicle. Once a determination was made that the hydrazine propellant was freezing, an assessment was made on the minimum amount of heat required to thaw propellant without placing the spacecraft in a power-negative state. The integrated spacecraft team performed root cause analysis and incrementally tested the propulsion system to recommission it in the face of an anomalous thruster valve. The recommissioning approach eventually lead to the development of a new propulsive state machine and Guidance Navigation and Control (GNC) thruster controller for detumbling. After recovering 3-axis attitude control, power and thermal stability, and establishing nominal communications, significant development and testing was required to ensure the vehicle could operate in the presence of a continued thruster anomaly. This effort enabled CAPSTONE to execute future propulsive maneuvers with an open thruster valve. The resultant updates were tested on Terran Orbital\u27s Hardware-in-the-Loop (HITL) platform in partnership with Stellar Exploration. A comparison of GNC subsystem requirements will be presented pre-and post-anomaly, based on the resulting capability and restrictions of the propulsion system to meet mission objectives. Ultimately, the spacecraft was successfully recovered from body rates exceeding 120 deg/s, allowing the CAPSTONE spacecraft to continue its mission, including successful insertion into NRHO in November 2022. An examination of the lessons learned for future deep space small satellite missions is also discussed herein

Mission Dodona: Electronic Power System Design, Analysis and Integration

“Dodona” is USC’s third CubeSat mission, and the electronic power system for this mission conforms to a centralized architecture common to the early-CubeSat class. The electronic power system is designed to power all satellite system components and any additional customer payload. A power budget is presented describing various operating configurations of the CubeSat and how its requirements are met in the design. The power system used a legacy Clyde Space 3U CubeSat Power System consisting of a combination of batteries and an Electronic Power System (EPS) to control charging, discharging, and voltage conversions for the system. The central architecture uses three major power lines to distribute power across the satellite, each subject to further regulation based on subsystem requirements. The system is reasonably efficient and has a high degree of utility, with significant heritage. This research discusses this centralized power system design and the testing methodology we used to validate, uncover and rectify issues prior to launch. While integrating the power system with other components on the satellite, problems were discovered and resolved through extensive testing. This paper presents insight into the operation of a nanosat electronic power system and the validation required to prepare it for flight

The Chlamydia muridarum plasmid revisited : new insights into growth kinetics.

Background: Research in chlamydial genetics is challenging because of its obligate intracellular developmental cycle. In vivo systems exist that allow studies of different aspects of basic biology of chlamydiae, the murine Chlamydia muridarum model is one of great importance and thus an essential research tool. C. muridarum carries a plasmid that has a role in virulence.  Our aim was to compare and contrast the C. muridarum plasmid-free phenotype with that of a chromosomally isogenic plasmid-bearing strain, through the inclusion phase of the developmental cycle. Methods: We measured infectivity for plasmid bearing and plasmid-cured C. muridarum by inclusion forming assays in McCoy cells and in parallel bacterial chromosome replication by quantitative PCR, throughout the developmental cycle. In addition to these studies, we have carefully monitored chlamydial inclusion formation by confocal microscopy and transmission electron microscopy. A new E.coli/chlamydial shuttle vector (pNigg::GFP) was constructed using standard cloning technology and used to transform C. muridarum for further phenotypic studies. Results: We have advanced the definition of the chlamydial phenotype away from the simple static observation of mature inclusions and redefined the C. muridarum plasmid-based phenotype on growth profile and inclusion morphology. Our observations on the growth properties of plasmid-cured C. muridarum challenge the established interpretations, especially with regard to inclusion growth kinetics. Introduction of the shuttle plasmid pNigg::GFP into plasmid-cured C. muridarum restored the wild-type plasmid-bearing phenotype and confirmed that loss of the plasmid was the sole cause for the changes in growth and chromosomal replication. Conclusions: Accurate growth curves and sampling at multiple time points throughout the developmental cycle is necessary to define plasmid phenotypes.  There are subtle but important (previously unnoticed) differences in the overall growth profile of plasmid-bearing and plasmid-free C. muridarum.  We have proven that the differences described are solely due to the plasmid pNigg

Technology and international climate policy

Both the nature of international climate policy architectures and the development and diffusion of new energy technologies could dramatically influence future costs of reducing global emissions of greenhouse gases. This paper explores the implications of interactions between technology availability and performance and international policy architectures for technology choice and the social cost of limiting atmospheric CO2 concentrations to 500 ppm by the year 2095. Key issues explored in the paper include the role of bioenergy production with CO2 capture and storage (CCS), overshoot concentration pathways, and the sensitivity of mitigation costs to policy and technology

Exploring aspects of agile software development risk – results from a MLR

Agile software development methods are widely used by software organisations, focusing on short developmental life cycles and customer satisfaction through the iterative and incremental development of software products. Despite their popularity, these methods present risks that may be underappreciated. This paper examines certain risks attributed to agile software development, with a focus on the lack of documentation, scope creep, technical debt and job satisfaction. Through the application of a multivocal literature review, we find that agile software development can greatly benefit projects. However, when agile methods are implemented inappropriately or sub-optimally, projects risk over-spending, delayed or defective software, employee turnover, and overall decreased productivity. Understanding the risks associated with agile software development can help practitioners to achieve higher efficiency and success in their software development projects