The global nitrogen regulator GlnR is a direct transcriptional repressor of the key gluconeogenic gene pckA in actinomycetes.

In most actinomycetes, GlnR governs both nitrogen and non-nitrogen metabolisms (e.g., carbon, phosphate, and secondary metabolisms). Although GlnR has been recognized as a global regulator, its regulatory role in central carbon metabolism [e.g., glycolysis, gluconeogenesis, and the tricarboxylic acid (TCA) cycle] is largely unknown. In this study, we characterized GlnR as a direct transcriptional repressor of the pckA gene that encodes phosphoenolpyruvate carboxykinase, catalyzing the conversion of the TCA cycle intermediate oxaloacetate to phosphoenolpyruvate, a key step in gluconeogenesis. Through the transcriptomic and quantitative real-time PCR analyses, we first showed that the pckA transcription was upregulated in the glnR null mutant of Amycolatopsis mediterranei. Next, we proved that the pckA gene was essential for A. mediterranei gluconeogenesis when the TCA cycle intermediate was used as a sole carbon source. Furthermore, with the employment of the electrophoretic mobility shift assay and DNase I footprinting assay, we revealed that GlnR was able to specifically bind to the pckA promoter region from both A. mediterranei and two other representative actinomycetes (Streptomyces coelicolor and Mycobacterium smegmatis). Therefore, our data suggest that GlnR may repress pckA transcription in actinomycetes, which highlights the global regulatory role of GlnR in both nitrogen and central carbon metabolisms in response to environmental nutrient stresses. IMPORTANCE: The GlnR regulator of actinomycetes controls nitrogen metabolism genes and many other genes involved in carbon, phosphate, and secondary metabolisms. Currently, the known GlnR-regulated genes in carbon metabolism are involved in the transport of carbon sources, the assimilation of short-chain fatty acid, and the 2-methylcitrate cycle, although little is known about the relationship between GlnR and the TCA cycle and gluconeogenesis. Here, based on the biochemical and genetic results, we identified GlnR as a direct transcriptional repressor of pckA, the gene that encodes phosphoenolpyruvate carboxykinase, a key enzyme for gluconeogenesis, thus highlighting that GlnR plays a central and complex role for dynamic orchestration of cellular carbon, nitrogen, and phosphate fluxes and bioactive secondary metabolites in actinomycetes to adapt to changing surroundings.

Assessing the reinforced molecular/mechanical behaviors of GOs@Mo-MOFs films deposited via electrophoresis onto microdevices: Experimental and theoretical perspectives.

One of the primary hurdles in microdevice fabrication lies in ascertaining the most impactful tactics for adapting metal surfaces. Through a one-pot tackle and distinct mechanochemical reactions evoked by 15 min aqueous wet sand-milling (SM-15), we successfully grafted Mo-based metal-organic frameworks (Mo-MOFs) onto graphene oxides (GOs). Following this, a convenient and readily scalable methodology of electrophoretic deposition was implemented to create controllable thickness of SM-15 GOs@Mo-MOFs lubricating films, achieving considerable enhancements of 143% and 91% in hardness and Young's modulus, respectively, when compared to those of SM-15 Mo-MOFs. The successful synthesis of SM-15 GOs@Mo-MOFs was corroborated using strategies such as x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. Analyses using the micro-tribotester indicated that the new film exhibited a lowest friction coefficient of roughly 0.5 when imposed with a load of 5 N and sliding speed of 8 mm/s. In addition, the optical profiler nano-indentation in situ scanning probe microscope revealed that SM-15 GOs@Mo-MOFs films had smaller and shallower scratches and grooves compared to SM-15 Mo-MOFs ones. The calculated results of key descriptors (EHOMO, ELUMO, ΔE, etc.) in density functional theory quantitatively disclosed the interaction mechanisms between GOs@Mo-MOFs molecules and microdevices. We first scrutinized the innate properties of molecule adsorption energy and frictional mechanical behaviors using synergetic cross-scale simulations, such as Monte Carlo and finite element methods. The expectation was that this process would motivate a valuable technique for shielding in the thriving micromanufacturing.

Coculture of Acinetobacter johnsonii and Shewanella putrefaciens Contributes to the ABC Transporter that Impacts Cold Adaption in the Aquatic Food Storage Environment.

Acinetobacter johnsonii and Shewanella putrefaciens were identified as specific spoilage organisms in aquatic food. The interactions among specific spoilage organisms under cold stress have a significant impact on the assembly of microbial communities, which play crucial roles in the spoilage and cold adaptation processes. The limited understanding of A. johnsonii and S. putrefaciens interactions in the cold adaptation mechanism hinders the elucidation of their roles in protein and metabolism levels. 4D quantitative proteomic analysis showed that the coculture of A. johnsonii and S. putrefaciens responds to low temperatures through ABC transporter proteins, resulting in phospholipid transport and inner membrane components. SapA and FtsX proteins were significantly upregulated, while LolC, LolD, LolE, PotD, PotA, PotB, and PotC proteins were significantly downregulated. Metabolome assays revealed that metabolites of glutathione and spermidine/putrescin were significantly upregulated, while metabolites of arginine/lysine/ornithine were significantly downregulated and involved in the ABC transporter metabolism. The results of ultramicroscopic analyses showed that the coculture of A. johnsonii and S. putrefaciens surface combined with the presence of the leakage of intracellular contents, suggesting that the bacteria were severely damaged and wrinkled to absorb metabolic nutrients and adapt to cold temperatures.

Effects of Internal Stress and Hydrogen Penetration on the Performance of Er2O3 Coatings as Hydrogen Permeation Barriers.

Ceramic coatings that can effectively prevent hydrogen permeation have a wide range of applications in hydrogen energy and nuclear fusion reactors. In this study, for the first time, the internal stress of Er2O3 coatings was found to be a key factor that could determine their hydrogen permeation resistance and lifespan. The internal stress was controlled by designing layered Er2O3 coatings. The internal stress increased with an increasing number of Er2O3 layers. When the number of layers was below 15, the increased internal stress did not adversely affect the coating performance and might help to increase its hydrogen permeation resistance. Although the overall thickness of the 15-layer Er2O3 coating was only 97 nm, its hydrogen permeation reduction factor (PRF) reached the highest value of 626, whereas a further increase in the internal stress detrimentally affected the ability of the coating to reduce hydrogen permeation. In addition, the experimental observations and simulation results revealed that the performance of the Er2O3 coatings was related to the hydrogen atoms that penetrated the coating, which weakened the Er-O bonds and consequently decreased the Er2O3 fracture limit. This study provides insights into the effects of internal stress and hydrogen penetration on the performance of ceramic coatings as hydrogen permeation barriers and will help guide strategies for the structure design of hydrogen permeation barriers possessing high PRFs and long lifespans.

The Relationship Between Static Characteristics of Physicians and Patient Consultation Volume in Internet Hospitals: Quantitative Analysis.

BACKGROUND: Internet medical treatment, also known as telemedicine, represents a paradigm shift in health care delivery. This contactless model allows patients to seek medical advice remotely, often before they physically visit a doctor's clinic. Herein, physicians are in a relatively passive position, as patients browse and choose their health care providers. Although a wealth of experience is undoubtedly a draw for many patients, it remains unclear which specific facets of a doctor's credentials and accomplishments patients prioritize during their selection process. OBJECTIVE: Our primary aim is to delve deeper into the correlation between physicians' static characteristics-such as their qualifications, experiences, and profiles on the internet-and the number of patient visits they receive. We seek to achieve this by analyzing comprehensive internet hospital data from public hospitals. Furthermore, we aim to offer insights into how doctors can present themselves more effectively on web-based platforms, thereby attracting more patients and improving overall patient satisfaction. METHODS: We retrospectively gathered web-based diagnosis and treatment data from the First Affiliated Hospital of Guangxi Medical University in 2023. These data underwent rigorous analysis, encompassing basic descriptive statistics, correlation analyses between key factors in doctors' internet-based introductions, and the number of patient consultation visits. Additionally, we conducted subgroup analyses to ascertain the independence of these vital factors. To further distill the essence from these data, we used nonnegative matrix factorization to identify crucial demographic characteristics that significantly impact patient choice. RESULTS: The statistical results suggested that there were significant differences in the distribution of consultation volume (P<.001), and the correlation analysis results suggested that there was a strong correlation between the two groups of data (ρ=0.93; P<.001). There was a correlation between the richness of a profile and popularity (P<.001). Patients were more interested in physicians with advanced titles, doctoral degrees, social activities, and scientific achievements (P<.001) as well as other institutional visit experiences (P=.003). More prosperous social activities, scientific achievements, experiences of other institutional visits, and awards were more common among people with advanced professional titles. Doctoral degrees remained attractive to patients when data were limited to senior physicians (P<.001). Patients trusted the medical staff with advanced titles, social activities, scientific achievements, and doctoral degrees (P<.001). CONCLUSIONS: Patient preferences for choosing a health care provider differed significantly between free and paid consultations. Notably, patients tended to trust doctors with advanced professional titles more and were more likely to seek out those with doctoral qualifications over other professional ranks. Additionally, physicians who actively participated in social events and scientific endeavors often had an advantage in attracting new patients. Given these insights, doctors who invest in enhancing their personal and professional experiences within these domains are likely to see increased popularity and patient satisfaction.

Effect of cryogenic cycling on mechanical properties of ZrTiCuNiBe bulk metallic glass.

The effect of deep cryogenic cycle treatment (DCT) on Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit-1) bulk metallic glass (BMG) prepared from high-purity raw materials was investigated. After DCT, no obvious rejuvenation of the samples was detected. With an increasing number of cryogenic cycles, the hardness of the samples first decreased and then increased, the room-temperature compression plasticity first increased and then generally remained unchanged, and the impact toughness underwent almost no obvious change. The absence of rejuvenation was attributed to the high fragility index (47-50) and high glass forming ability (GFA) of the material. As lower purity of the raw materials is expected in practical applications, DCT of Vit-1 BMG prepared from low-purity raw materials was also performed. After DCT, the samples prepared with the lower-purity raw materials were clearly rejuvenated, and the room-temperature mechanical properties improved significantly.Both the compression plasticity and impact toughness reached peak values after 5 cryogenic cycles. The initial impurities (including Y and O) had a complex and comprehensive effect on the deformation mechanism of the BMG during DCT. Our findings indicate that the structural heterogeneity, fragility index, and GFA of the BMG alter the effect of DCT.