Display omitted
•The first structure of Saccharomyces cerevisiae ATE1 (ScATE1) has been determined.•Cryo-EM and SAXS data corroborate crystalline and solution behavior of ScATE1.•Apo ScATE1 contrasts ...with the structure of Zn2+-bound Kluyveromyces lactis ATE1.•Based on structural data, a mechanism of N-terminal arginylation has been proposed.
Eukaryotic post-translational arginylation, mediated by the family of enzymes known as the arginyltransferases (ATE1s), is an important post-translational modification that can alter protein function and even dictate cellular protein half-life. Multiple major biological pathways are linked to the fidelity of this process, including neural and cardiovascular developments, cell division, and even the stress response. Despite this significance, the structural, mechanistic, and regulatory mechanisms that govern ATE1 function remain enigmatic. To that end, we have used X-ray crystallography to solve the crystal structure of ATE1 from the model organism Saccharomyces cerevisiae ATE1 (ScATE1) in the apo form. The three-dimensional structure of ScATE1 reveals a bilobed protein containing a GCN5-related N-acetyltransferase (GNAT) fold, and this crystalline behavior is faithfully recapitulated in solution based on size-exclusion chromatography-coupled small angle X-ray scattering (SEC-SAXS) analyses and cryo-EM 2D class averaging. Structural superpositions and electrostatic analyses point to this domain and its domain-domain interface as the location of catalytic activity and tRNA binding, and these comparisons strongly suggest a mechanism for post-translational arginylation. Additionally, our structure reveals that the N-terminal domain, which we have previously shown to bind a regulatory Fe-S cluster, is dynamic and disordered in the absence of metal bound in this location, hinting at the regulatory influence of this region. When taken together, these insights bring us closer to answering pressing questions regarding the molecular-level mechanism of eukaryotic post-translational arginylation.
Eukaryotic arginylation is an essential post-translational modification that modulates protein stability and regulates protein half-life. Arginylation is catalyzed by a family of enzymes known as the ...arginyl-tRNA transferases (ATE1s), which are conserved across the eukaryotic domain. Despite their conservation and importance, little is known regarding the structure, mechanism, and regulation of ATE1s. In this work, we show that ATE1s bind a previously undiscovered Fe-S cluster that is conserved across evolution. We characterize the nature of this Fe-S cluster and find that the presence of the Fe-S cluster in ATE1 is linked to its arginylation activity, both in vitro and in vivo, and the initiation of the yeast stress response. Importantly, the ATE1 Fe-S cluster is oxygen-sensitive, which could be a molecular mechanism of the N-degron pathway to sense oxidative stress. Taken together, our data provide the framework of a cluster-based paradigm of ATE1 regulatory control.
In this paper, we provide an overview of financial development in Vietnam. Particularly, a new approach of this study is to measure financial development through improvements in depth, efficiency and ...access of the banking system and stock market. Further, the study examines the factors significantly affecting financial development in Vietnam. The data are collected in Vietnam, an emerging country with a limited financial development. We employ the Autoregressive Distributed Lag (ARDL) approach, which generates a high reliability and suits data characteristics of emerging countries like Vietnam. We observe that Vietnam's banking system plays a key role in supplying credits to the economy while the nascent stock market at a limited size shows its potential for a considerable growth in the future. We also find the influential determinants of financial development in Vietnam including real estate market (RE), economic growth (EG), consumer price index (CPI), and global financial crisis (GFC). These findings are essential for Vietnamese authorities in providing practical solutions in order to build a sustainable and synchronous financial development. They are also first empirical evidence relating to an overview of financial development in an emerging country, so they are not only valuable to Vietnam but also crucial to other emerging economies.
To evaluate the etiology and clinical features of bacterial meningitis (BM) in adults during 2015–2018 in Vietnam, a retrospective study using 102 patients was performed at the National Hospital of ...Tropical Diseases. BM occurred throughout the year, peaking in July–September. A total of 80.4% BM patients were males over 40 years old. The proportion of patients with underlying diseases was 41.2% and those in contact with pigs or pork products was 30.4%. Common manifestations include stiff neck, Kernig’s sign, headache, fever/hypothermia, and altered consciousness. The cerebrospinal fluid (CSF) had high protein concentration (median: 3.2 g/L, range: 1.3–6.2) and leukocytes (median: 1,312 cell/mm3, range: 234–2,943). Moreover, 29.4% meningitis cases were associated with septicemia. Streptococcus suis was the main cause (72.5%), followed by Pneumococcus (6.8%) and a few other bacteria. Factors associated with S. suis risk were male sex (OR: 8.29, 95% CI: 2.83–24.33), over 40 years old (OR: 3.55, 95% CI: 1.28–9.87), drinking habits (OR: 3.78, 95% CI: 1.03–13.72), headache (OR: 6.19, 95% CI: 2.17–17.65), fever/hypothermia (OR: 5.17, 95% CI: 1.97–13.56) and ≥2.0 ng/mL procalcitonin (OR: 2.72, 95% CI: 1.07–6.89). Education on S. suis and nosocomial infection prevention, as well as pneumococcal vaccination use, should be continued.
Thuan Chau is a serious district affected by forest fire in Vietnam, especially in 2016; however, no forest fire prediction research has been conducted for this region. Thus, knowledge of spatial ...patterns of fire danger of the district plays a key role in forest succession and ecological implications. This study's aim was to analyze the spatial pattern of fire danger for the tropical forest of Thuan Chau district using advanced machine learning algorithms, Support Vector Machine classifier (SVMC), Random Forests (RF), and Multilayer Perceptron Neural Network (MLP-Net). For this purpose, a GIS database for the study area was established with 564 forest fire locations and ten forest fire variables. Then, Pearson correlation method was used to assess the correlation of the variables with the forest fire. In the next step, three forest fire danger models, SVMC, RF, and MLP-Net, were trained and validated. Finally, global performance of these models was assessed using the classification accuracy (ACC), Kappa statistics (KS), Area under the curve (AUC). In addition, Wilcoxon signed-rank test was employed to check the prediction performance of these models. The result shows the three models performed well; however, the MLP-Net model has the highest prediction performance (ACC = 81.7, KS = 0.633, and AUC = 0.894), followed by the RF model (ACC = 81.1, KS = 0.621, and AUC = 0.883), and the SVMC model (ACC = 80.2, KS = 0.604, and AUC = 0.867). The result in this study is useful for the local authority and forest manager in forest management and fire suppression.
•Spatial pattern assessment of tropical forest fire using advanced machine learning, SVMC, RF, and MLP-Net.•Predictive ability of forest fire variables was analyzed using Pearson correlation.•MLP-Net is the best, providing >85% prediction accuracy for future forest fire.
To estimate the incubation period of Vietnamese confirmed COVID-19 cases.
Only confirmed COVID-19 cases who are Vietnamese and locally infected with available data on date of symptom onset and ...clearly defined window of possible SARS-CoV-2 exposure were included. We used three parametric forms with Hamiltonian Monte Carlo method for Bayesian Inference to estimate incubation period for Vietnamese COVID-19 cases. Leave-one-out Information Criterion was used to assess the performance of three models.
A total of 19 cases identified from 23 Jan 2020 to 13 April 2020 was included in our analysis. Average incubation periods estimated using different distribution model ranged from 6.0 days to 6.4 days with the Weibull distribution demonstrated the best fit to the data. The estimated mean of incubation period using Weibull distribution model was 6.4 days (95% credible interval (CrI): 4.89-8.5), standard deviation (SD) was 3.05 (95%CrI 3.05-5.30), median was 5.6, ranges from 1.35 to 13.04 days (2.5th to 97.5th percentiles). Extreme estimation of incubation periods is within 14 days from possible infection.
This analysis provides evidence for an average incubation period for COVID-19 of approximately 6.4 days. Our findings support existing guidelines for 14 days of quarantine of persons potentially exposed to SARS-CoV-2. Although for extreme cases, the quarantine period should be extended up to three weeks.
Preventing surface damage is crucial for optimal machine performance, with lubricants and additives playing a vital role in achieving this objective. This study specifically focuses on evaluating the ...influence of fly-ash additives on the wear resistance of machine components when incorporated into lubricant oil. The experiments were conducted following ASTM standard operating conditions, utilizing the four-ball wear test to measure the scratch width and weight loss of balls using different lubricant oil formulations, including 0, 0.1%, 0.5%, 0.75%, and 1% additive. The findings demonstrate that the inclusion of 0.5% fly ash additive in the lubricant oil results in a significant reduction in both scratch width and weight loss of the balls. However, it should be noted that higher additive ratios may lead to increased scratch width and weight loss due to the agglomeration of the fly ash particles on the sliding surfaces. To achieve optimal effectiveness in reducing friction and wear, it is recommended to carefully control the content of fly ash within an appropriate range. Furthermore, this study highlights the width of scratches on balls as a reliable indicator for assessing the anti-wear properties of oils. The insights gained from this research offer valuable guidance to manufacturers in the selection of suitable anti-wear oils for specific applications. Further investigations could explore the impact of different lubricants and additive ratios to identify the most appropriate lubrication parameters. Overall, this study contributes to a better understanding of the effects of fly ash additives on the performance of lubricant oil and provides practical guidance for optimizing lubrication strategies in diverse industrial contexts.
At the 26th UN Climate Change Conference in late 2021, Vietnam set a target of achieving net-zero carbon (CO2) emissions by 2050. However, the country’s rapid economic growth, urbanization, and ...industrialization have historically relied on coal-based energy, a source of significant greenhouse gas (GHG) emissions. Although contributing only 0.8% of the world’s emissions over the last two decades, Vietnam currently has one of the fastest increasing GHG emissions rates per capita. Over the 2000–2015 period, Vietnam’s per capita gross domestic product increased from $390 to $2,000, and CO2 emissions nearly quadrupled. Hence, this research explores the causal relationships among CO2 emissions, economic growth, foreign direct investment, renewable energy usage, and urban population in Vietnam over the period from 1990 to 2018 using the Environment Kuznets Curve. An autoregressive distributed lag bounds testing technique for measuring integration is utilized to investigate the long-run relationship. Results indicate that economic growth increases with CO2 emissions until a certain threshold level and then CO2 emissions decrease, thereby supporting the environmental Kuznets curve theory for Vietnam. Furthermore, this study examines the causal relationship among variables using a Granger causality model and determines that FDI, urban population, and renewable energy consumption play an important role and have substantial impact on carbon emission in Vietnam.
Single-point incremental forming (SPIF) has drawn much attention recently due to its flexibility in making parts for rapid prototypes and small samples. Several studies have pointed out the benefits ...of using ultrasonic vibration (UV) in SPIF experimentally. This study verifies the effect of UV in reducing the forming forces by performing numerical simulations. In addition, the effect of several process parameters, including tool diameters, rotational speeds, step sizes, and ultrasonic vibration amplitudes, is investigated in detail. It is found that an increase in the tool rotational speed and vibrating amplitude decreases forming forces, whereas an increase in the vertical step size increases forming forces.
PDF
