OsBCAT2, a gene responsible for the degradation of branched-chain amino acids, positively regulates salt tolerance by promoting the synthesis of vitamin B5.

Salt stress negatively affects rice growth, development and yield. Metabolic adjustments contribute to the adaptation of rice under salt stress. Branched-chain amino acids (BCAA) are three essential amino acids that cannot be synthesized by humans or animals. However, little is known about the role of BCAA in response to salt stress in plants. Here, we showed that BCAAs may function as scavengers of reactive oxygen species (ROS) to provide protection against damage caused by salinity. We determined that branched-chain aminotransferase 2 (OsBCAT2), a protein responsible for the degradation of BCAA, positively regulates salt tolerance. Salt significantly induces the expression of OsBCAT2 rather than BCAA synthesis genes, which indicated that salt mainly promotes BCAA degradation and not de novo synthesis. Metabolomics analysis revealed that vitamin B5 (VB5) biosynthesis pathway intermediates were higher in the OsBCAT2-overexpressing plants but lower in osbcat2 mutants under salt stress. The salt stress-sensitive phenotypes of the osbcat2 mutants are rescued by exogenous VB5, indicating that OsBCAT2 affects rice salt tolerance by regulating VB5 synthesis. Our work provides new insights into the enzymes involved in BCAAs degradation and VB5 biosynthesis and sheds light on the molecular mechanism of BCAAs in response to salt stress.

A Proactive Recognition System for Detecting Commercial Vehicle Driver's Distracted Behavior.

Road traffic accidents regarding commercial vehicles have been demonstrated as an important culprit restricting the steady development of the social economy, which are closely related to the distracted behavior of drivers. However, the existing driver's distracted behavior surveillance systems for monitoring and preventing the distracted behavior of drivers still have some shortcomings such as fewer recognition objects and scenarios. This study aims to provide a more comprehensive methodological framework to demonstrate the significance of enlarging the recognition objects, scenarios and types of the existing driver's distracted behavior recognition systems. The driver's posture characteristics were primarily analyzed to provide the basis of the subsequent modeling. Five CNN sub-models were established for different posture categories and to improve the efficiency of recognition, accompanied by a holistic multi-cascaded CNN framework. To suggest the best model, image data sets of commercial vehicle driver postures including 117,410 daytime images and 60,480 night images were trained and tested. The findings demonstrate that compared to the non-cascaded models, both daytime and night cascaded models show better performance. Besides, the night models exhibit worse accuracy and better speed relative to their daytime model counterparts for both non-cascaded and cascaded models. This study could be used to develop countermeasures to improve driver safety and provide helpful information for the design of the driver's real-time monitoring and warning system as well as the automatic driving system. Future research could be implemented to combine the vehicle state parameters with the driver's microscopic behavior to establish a more comprehensive proactive surveillance system.

Aspergillus fumigatus Induces the Release of IL-8 and MCP-1 by Activating Nuclear Transcription Through Dectin-1 and CR3 Receptors in Alveolar Epithelial Cells.

Invasive pulmonary aspergillosis induced by the pathogenic fungus Aspergillus fumigatus is one of the common fatal complications in immunocompromised patients. Lung epithelial cells play an important role in host immune defense against A. fumigatus. However, the interaction between lung epithelial cells and A. fumigatus conidia is not fully understood. In this study, we used the swollen conidia of A. fumigatus to stimulate the type II lung epithelial A549 cells. Results showed that swollen conidia could significantly increase RNA transcription and protein expression of interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1), but not TNF-α in A549 cells in a time-dependent manner. Moreover, serum opsonization was able to improve the release of inflammatory factors induced by swollen conidia. Blocking of the dectin-1 or CR3 receptors, or both simultaneously, in the A549 cells could decrease the release of IL-8 and MCP-1. Additionally, blocking dectin-1 or CR3 could inhibit the transcription of nuclear factor NF-κB that was activated by swollen conidia. Here we reported for the first time that dectin-1 and CR3 receptors in A549 cells mediate the release of pro-inflammatory factors IL-8 and MCP-1 induced by A. fumigatus.

Video Summarization Based on Mutual Information and Entropy Sliding Window Method.

This paper proposes a video summarization algorithm called the Mutual Information and Entropy based adaptive Sliding Window (MIESW) method, which is specifically for the static summary of gesture videos. Considering that gesture videos usually have uncertain transition postures and unclear movement boundaries or inexplicable frames, we propose a three-step method where the first step involves browsing a video, the second step applies the MIESW method to select candidate key frames, and the third step removes most redundant key frames. In detail, the first step is to convert the video into a sequence of frames and adjust the size of the frames. In the second step, a key frame extraction algorithm named MIESW is executed. The inter-frame mutual information value is used as a metric to adaptively adjust the size of the sliding window to group similar content of the video. Then, based on the entropy value of the frame and the average mutual information value of the frame group, the threshold method is applied to optimize the grouping, and the key frames are extracted. In the third step, speeded up robust features (SURF) analysis is performed to eliminate redundant frames in these candidate key frames. The calculation of Precision, Recall, and Fmeasure are optimized from the perspective of practicality and feasibility. Experiments demonstrate that key frames extracted using our method provide high-quality video summaries and basically cover the main content of the gesture video.

RNALocate: a resource for RNA subcellular localizations.

Increasing evidence has revealed that RNA subcellular localization is a very important feature for deeply understanding RNA's biological functions after being transported into intra- or extra-cellular regions. RNALocate is a web-accessible database that aims to provide a high-quality RNA subcellular localization resource and facilitate future researches on RNA function or structure. The current version of RNALocate documents more than 37 700 manually curated RNA subcellular localization entries with experimental evidence, involving more than 21 800 RNAs with 42 subcellular localizations in 65 species, mainly including Homo sapiens, Mus musculus and Saccharomyces cerevisiae etc. Besides, RNA homology, sequence and interaction data have also been integrated into RNALocate. Users can access these data through online search, browse, blast and visualization tools. In conclusion, RNALocate will be of help in elucidating the entirety of RNA subcellular localization, and developing new prediction methods. The database is available at http://www.rna-society.org/rnalocate/.

Role of the small GTPase Rho1 in cell wall integrity, stress response, and pathogenesis of Aspergillus fumigatus.

Aspergillus fumigatus is a major pathogen of invasive pulmonary aspergillosis. The small GTPase, Rho1, of A. fumigatus is reported to comprise a potential regulatory subunit of ß-1,3-glucan synthase and is indispensable for fungal viability; however, the role of AfRho1 on the growth, cell wall integrity, and pathogenesis of A. fumigatus is still poorly understood. We constructed A. fumigatus mutants with conditional- and overexpression of Rho1 and found that defects of AfRho1 expression led to the reduction of ß-1,3-glucan and glucosamine moieties on the cell wall, with down-regulated transcription of genes in the cell wall integrity signaling pathway and a decrease of calcofluor white (CFW)-stimulated mitogen-activated protein kinase (MpkA) phosphorylation and cytoplasmic leakage compared to those of the wild-type strain (WT). In addition, down-regulation of AfRho1 expression caused much higher sensitivity of A. fumigatus to H2O2 and alkaline pH compared to that of WT. Decrease of AfRho1 expression also attenuated the A. fumigatus pathogenicity in Galleria mellonella and inhibited conidial internalization into lung epithelial cells and inflammatory factor release. In contrast, overexpression of Rho1 did not alter A. fumigatus morphology, susceptibility to cell wall stresses, or pathogenicity relative to its parental strain. Taken together, our findings support AfRho1 as an essential regulator of the cell wall integrity, stress response, and pathogenesis of A. fumigatus.

Pro54DB: a database for experimentally verified sigma-54 promoters.

Summary: In prokaryotes, the σ54 promoters are unique regulatory elements and have attracted much attention because they are in charge of the transcription of carbon and nitrogen-related genes and participate in numerous ancillary processes and environmental responses. All findings on σ54 promoters are favorable for a better understanding of their regulatory mechanisms in gene transcription and an accurate discovery of genes missed by the wet experimental evidences. In order to provide an up-to-date, interactive and extensible database for σ54 promoter, a free and easy accessed database called Pro54DB (σ54 promoter database) was built to collect information of σ54 promoter. In the current version, it has stored 210 experimental-confirmed σ54 promoters with 297 regulated genes in 43 species manually extracted from 133 publications, which is helpful for researchers in fields of bioinformatics and molecular biology. Availability and Implementation: Pro54DB is freely available on the web at http://lin.uestc.edu.cn/database/pro54db with all major browsers supported. Contacts: greatchen@ncst.edu.cn or hlin@uestc.edu.cn

Gliotoxin destructs the pulmonary epithelium barrier function by reducing cofilin oligomer formation to promote the dissolution of actin stress fibers.

The destruction of pulmonary epithelium is a major feature of lung diseases caused by the fungal pathogen Aspergillus fumigatus (A. fumigatus). Gliotoxin, a major mycotoxin of A. fumigatus, is widely postulated to be associated with the tissue invasion. However, the mechanism is unclear. In this study, we first discovered that cofilin, a regulator of actin dynamics in the pulmonary epithelial cells, existed mainly in the form of oligomer, which kept it unable to depolymerize actin filaments. Gliotoxin could reduce the formation of cofilin oligomer and promote the release of active cofilin monomer by regulating cofilin phosphorylation balance. Then, the active cofilin induced the dissolution of actin stress fibers to result in the disruption of pulmonary epithelium barrier function. Collectively, our study revealed a novel mechanism of gliotoxin destructing lung epithelium barrier function and for the first time indicated the role of cofilin oligomer in this process.

Epidemiology and Molecular Characterizations of Azole Resistance in Clinical and Environmental Aspergillus fumigatus Isolates from China.

Azole resistance in Aspergillus fumigatus has emerged as a worldwide public health problem. We sought here to demonstrate the occurrence and characteristics of azole resistance in A. fumigatus from different parts of China. A total of 317 clinical and 144 environmental A. fumigatus isolates from 12 provinces were collected and subjected to screening for azole resistance. Antifungal susceptibility, cyp51A gene sequencing, and genotyping were carried out for all suspected azole-resistant isolates and a subset of azole-susceptible isolates. As a result, 8 (2.5%) clinical and 2 (1.4%) environmental A. fumigatus isolates were identified as azole resistant. Five azole-resistant strains exhibit the TR34/L98H mutation, whereas four carry the TR34/L98H/S297T/F495I mutation in the cyp51A gene. Genetic typing and phylogenetic analysis showed that there was a worldwide clonal expansion of the TR34/L98H isolates, while the TR34/L98H/S297T/F495I isolates from China harbored a distinct genetic background with resistant isolates from other countries. High polymorphisms existed in the cyp51A gene that produced amino acid changes among azole-susceptible A. fumigatus isolates, with N248K being the most common mutation. These data suggest that the wide distribution of azole-resistant A. fumigatus might be attributed to the environmental resistance mechanisms in China.

Surface Recombination Limited Lifetimes of Photoexcited Carriers in Few-Layer Transition Metal Dichalcogenide MoS2.

We present results on photoexcited carrier lifetimes in few-layer transition metal dichalcogenide MoS2 using nondegenerate ultrafast optical pump-probe technique. Our results show a sharp increase of the carrier lifetimes with the number of layers in the sample. Carrier lifetimes increase from few tens of picoseconds in monolayer samples to more than a nanosecond in 10-layer samples. The inverse carrier lifetime was found to scale according to the probability of the carriers being present at the surface layers, as given by the carrier wave function in few layer samples, which can be treated as quantum wells. The carrier lifetimes were found to be largely independent of the temperature, and the inverse carrier lifetimes scaled linearly with the photoexcited carrier density. These observations are consistent with defect-assisted carrier recombination, in which the capture of electrons and holes by defects occurs via Auger scatterings. Our results suggest that carrier lifetimes in few-layer samples are surface recombination limited due to the much larger defect densities at surface layers compared with the inner layers.

Ultrafast dynamics of defect-assisted electron-hole recombination in monolayer MoS2.

In this Letter, we present nondegenerate ultrafast optical pump-probe studies of the carrier recombination dynamics in MoS2 monolayers. By tuning the probe to wavelengths much longer than the exciton line, we make the probe transmission sensitive to the total population of photoexcited electrons and holes. Our measurement reveals two distinct time scales over which the photoexcited electrons and holes recombine; a fast time scale that lasts ∼ 2 ps and a slow time scale that lasts longer than ∼ 100 ps. The temperature and the pump fluence dependence of the observed carrier dynamics are consistent with defect-assisted recombination as being the dominant mechanism for electron-hole recombination in which the electrons and holes are captured by defects via Auger processes. Strong Coulomb interactions in two-dimensional atomic materials, together with strong electron and hole correlations in two-dimensional metal dichalcogenides, make Auger processes particularly effective for carrier capture by defects. We present a model for carrier recombination dynamics that quantitatively explains all features of our data for different temperatures and pump fluences. The theoretical estimates for the rate constants for Auger carrier capture are in good agreement with the experimentally determined values. Our results underscore the important role played by Auger processes in two-dimensional atomic materials.

Characteristics of qacA/B-positive Staphylococcus aureus isolated from patients and a hospital environment in China.

OBJECTIVES: This study was designed to demonstrate the characteristics of qacA/B-positive Staphylococcus aureus in China. METHODS: One hundred and forty-five MRSA and 178 MSSA from clinical specimens from seven hospitals in different regions of China, 70 MRSA from superficial sites of patients and 106 MRSA from environmental samples from an ICU were collected and screened for the presence of the qacA/B gene. The qacA/B-positive isolates and 72 randomly selected qacA/B-negative control isolates were further characterized by MLST, spa typing and detection of toxin genes, as well as antimicrobial and chlorhexidine susceptibility. SCCmec typing was conducted for MRSA. PFGE was conducted for qacA/B-positive isolates. RESULTS: Twenty-five (7.8%) of the 321 MRSA isolates harboured qacA/B, including 11 isolates from clinical specimens (7.6%), 12 isolates from patients' superficial sites (17.1%) and 2 isolates from an ICU environment (1.9%). Ten and five qacA/B-positive MRSA were identified as ST239-t030-MRSA-III and ST239-t037-MRSA-III, respectively. Six PFGE clusters and five singletons were identified among the 25 qacA/B-positive MRSA. Only one (0.6%) of the 178 MSSA isolates harboured qacA/B. qacA/B carriage in MRSA was statistically associated with spa-t037 and the presence of mupA. Compared with qacA/B-negative MRSA, the qacA/B-positive MRSA exhibited a lower susceptibility to chlorhexidine and higher resistance rates to clindamycin and trimethoprim/sulfamethoxazole. CONCLUSIONS: Carriage of qacA/B, although it had a low prevalence, might be the main reason for declining susceptibility to chlorhexidine in MRSA from Chinese patients and is probably associated with spa-t037 and the presence of the mupA gene.

Evidence for the involvement of cofilin in Aspergillus fumigatus internalization into type II alveolar epithelial cells.

BACKGROUND: The internalization of Aspergillus fumigatus into alveolar epithelial cells (AECs) is tightly controlled by host cellular actin dynamics, which require close modulation of the ADF (actin depolymerizing factor)/cofilin family. However, the role of cofilin in A. fumigatus internalization into AECs remains unclear. RESULTS: Here, we demonstrated that germinated A. fumigatus conidia were able to induce phosphorylation of cofilin in A549 cells during the early stage of internalization. The modulation of cofilin activity by overexpression, knockdown, or mutation of the cofilin gene in A549 cells decreased the efficacy of A. fumigatus internalization. Reducing the phosphorylation status of cofilin with BMS-5 (LIM kinase inhibitor) or overexpression of the slingshot phosphatases also impeded A. fumigatus internalization. Both the C. botulimun C3 transferase (a specific RhoA inhibitor) and Y27632 (a specific ROCK inhibitor) reduced the internalization of A. fumigatus and the level of phosphorylated cofilin. ß-1,3-glucan (the major component of the conidial cell wall) and its host cell receptor dectin-1 did not seem to be associated with cofilin phosphorylation during A. fumigatus infection. CONCLUSION: These results indicated that cofilin might be involved in the modulation of A. fumigatus internalization into type II alveolar epithelial cells through the RhoA-ROCK-LIM kinase pathway.

[The cofilin of host cell and infection--A review].

Invasion of pathogens into host cells is the key process to consequently induce the infection, which depends on the actin cytoskeleton rearrangement. Cofilin in the host cell is one of the most important actin depolymerization factor that is essential responsing to the infection of several viruses, bacteria and fungi. Pathogenic microbes can induce biphasic remodeling of the actin cytoskeleton in host cells, accompanied by changes of phosphorylation of cofilin, which results in changes of cofilin activity. The modulation of host cofilin activity by mutation, knockdown, or overexpression can effectively inhibit the infection. Here we review the function and possible regulatory mechanism of host cofilin during the process of infection.

Comparative metabolomics combined with genome sequencing provides insights into novel wolfberry-specific metabolites and their formation mechanisms.

Wolfberry (Lycium, of the family Solanaceae) has special nutritional benefits due to its valuable metabolites. Here, 16 wolfberry-specific metabolites were identified by comparing the metabolome of wolfberry with those of six species, including maize, rice, wheat, soybean, tomato and grape. The copy numbers of the riboflavin and phenyllactate degradation genes riboflavin kinase (RFK) and phenyllactate UDP-glycosyltransferase (UGT1) were lower in wolfberry than in other species, while the copy number of the phenyllactate synthesis gene hydroxyphenyl-pyruvate reductase (HPPR) was higher in wolfberry, suggesting that the copy number variation of these genes among species may be the main reason for the specific accumulation of riboflavin and phenyllactate in wolfberry. Moreover, the metabolome-based neighbor-joining tree revealed distinct clustering of monocots and dicots, suggesting that metabolites could reflect the evolutionary relationship among those species. Taken together, we identified 16 specific metabolites in wolfberry and provided new insight into the accumulation mechanism of species-specific metabolites at the genomic level.

Integrated Metabolome and Transcriptome during Fruit Development Reveal Metabolic Differences and Molecular Basis between Lycium barbarum and Lycium ruthenicum.

Wolfberry (Lycium barbarum) is a traditional cash crop in China and is well-known worldwide for its outstanding nutritional and medicinal value. Lycium ruthenicum is a close relative of Lycium barbarum but differs significantly in size, color, flavor and nutritional composition. To date, the metabolic differences between the fruits of the two wolfberry varieties and the genetic basis behind them are unclear. Here, we compared metabolome and transcriptome data of two kinds of wolfberry fruits at five stages of development. Metabolome results show that amino acids, vitamins and flavonoids had the same accumulation pattern in various developmental stages of fruit but that Lycium ruthenicum accumulated more metabolites than Lycium barbarum during the same developmental stage, including L-glutamate, L-proline, L-serine, abscisic acid (ABA), sucrose, thiamine, naringenin and quercetin. Based on the metabolite and gene networks, many key genes that may be involved in the flavonoid synthesis pathway in wolfberry were identified, including PAL, C4H, 4CL, CHS, CHI, F3H, F3'H and FLS. The expression of these genes was significantly higher in Lycium ruthenicum than in Lycium barbarum, indicating that the difference in the expression of these genes was the main reason for the variation in flavonoid accumulation between Lycium barbarum and Lycium ruthenicum. Taken together, our results reveal the genetic basis of the difference in metabolomics between Lycium barbarum and Lycium ruthenicum and provide new insights into the flavonoid synthesis of wolfberry.

tRF-Gln-CTG-026 ameliorates liver injury by alleviating global protein synthesis.

tsRNAs (tRNA-derived small RNAs), as products of the stress response, exert considerable influence on stress response and injury regulation. However, it remains largely unclear whether tsRNAs can ameliorate liver injury. Here, we demonstrate the roles of tsRNAs in alleviating liver injury by utilizing the loss of NSun2 (NOP2/Sun domain family, member 2) as a tsRNAs-generating model. Mechanistically, the loss of NSun2 reduces methyluridine-U5 (m5U) and cytosine-C5 (m5C) of tRNAs, followed by the production of various tsRNAs, especially Class I tsRNAs (tRF-1s). Through further screening, we show that tRF-Gln-CTG-026 (tG026), the optimal tRF-1, ameliorates liver injury by repressing global protein synthesis through the weakened association between TSR1 (pre-rRNA-processing protein TSR1 homolog) and pre-40S ribosome. This study indicates the potential of tsRNA-reduced global protein synthesis in liver injury and repair, suggesting a potential therapeutic strategy for liver injury.

Modeling the temporal relationship between contributing factors and injury severities in rural single-vehicle alcohol-impaired driving crashes: Insights from random parameters logit models in the means and variances.

OBJECTIVES: Alcohol-impaired driving (A-ID) crashes have been acknowledged as fatality-concentrated while there is a limited understanding of how contributors relating to A-ID influence crash severity and lead to more severe injuries in rural areas. The current paper utilized North Carolina crash data to investigate the unobserved heterogeneity and temporal stability of the rural single-vehicle A-ID crash injury-severity determinants over a five-year period from 2014-2018. METHODS: Crash injury severities were estimated using a group of random parameters logit models in the means and variances with three categories of injury-severity determined as outcome variables including no injury, minor injury, and severe injury. Explanatory variables were selected across multiple factors that could be classified as roadway characteristics, environmental characteristics, crash characteristics, temporal characteristics, vehicle characteristics and driver characteristics. The temporal stability of the models was examined through a series of likelihood ratio tests. Marginal effects were also adopted to analyze the temporal stability of the explanatory variables. RESULTS: The result uncovers an overall temporal instability. Some contributors present relatively temporal stability such as female, turning, passenger car, motorcycle, vehicle age (5-9 years old), speed limit (<45 mph), curved segment, dry road surface, animal collision and overturned collision. Curved segment and dry road surface are found to consistently increase the possibility of severe injuries in rural alcohol-involved crashes. CONCLUSIONS: This paper can provide insights into preventing single-vehicle A-ID crashes and could potentially facilitate the development of single-vehicle A-ID crash injury mitigation policies in rural areas. More studies could be conducted adopting the advanced data-driven methods for A-ID crash prediction.

Temporal-spatial evolution analysis of severe traffic violations using three functional forms of models considering the diurnal variation of meteorology.

Traffic violations and crashes are inherently associated. Analysis of traffic violation frequency is a prerequisite for improvements in crash prevention and corresponding countermeasures. One of the essential works in the field of traffic violations relates to the exploration of the correlations between a certain violation type (e.g., speeding or safety belt use) and its causal factors (e.g., demographics and road types). Till now, the effects of spatiotemporal and meteorological factors on severe traffic violations, a general term for dangerous driving behaviors, have not been fully considered. Using the dataset consisting of daily severe traffic violations and meteorological conditions during 12 months in Jiangsu Province, China, violation performance functions were developed for three violation types (total violations, driving under the influence, and speeding) based on three models (Poisson regression, zero-inflated Poisson regression, and negative binomial model). The findings indicate that the negative binomial model has a better performance for traffic violation frequency estimation. Additionally, elastic analysis for three violation types relying on the negative binomial model was conducted to present the relationships between the explanatory variables and the expected violation frequency. The effects of spatiotemporal factors have revealed that the violation situations are significantly different in varying cities and the frequency of drunk driving shows a significant time instability. It is also found that rainy days will generate a decrease in the possibility of violation occurrence. With regard to temperature, a significant negative effect is found and the decrease in temperature will bring about an increase in violation frequency. Besides, traffic violation frequency is significantly increased during holidays with comfortable weather conditions. The conclusion of this study can provide insightful suggestions for the department of traffic enforcement to adjust the patrol plans according to the specified periods (weeks, months, or holidays) and weather conditions. Special rectification actions and targeted educational activities are also advised to be put forward simultaneously.

Lactate Dehydrogenase B Is Required for Pancreatic Cancer Cell Immortalization Through Activation of Telomerase Activity.

Telomerase activity is elevated in most cancer cells and is required for telomere length maintenance and immortalization of cancer cells. Glucose metabolic reprogramming is a hallmark of cancer and accompanied with increased expression of key metabolic enzymes. Whether these enzymes influence telomerase activity and cell immortalization remains unclear. In the current study, we screened metabolic enzymes using telomerase activity assay and identified lactate dehydrogenase B (LDHB) as a regulator of telomerase activity. Sodium lactate and sodium pyruvate did not influence telomerase activity, indicating LDHB regulates telomerase activity independent of its metabolism regulating function. Further studies revealed that LDHB directly interacted with TERT and regulated the interaction between TERT and TERC. Additionally, long-term knockdown of LDHB inhibited cancer cell growth and induced cell senescence in vitro and in vivo. Higher LDHB expression was detected in pancreatic cancer tissues compared with that in adjacent normal tissues and expression of LDHB correlated negatively with prognosis. Thus, we identified LDHB as the first glucose metabolic enzyme contributing to telomerase activity and pancreatic cancer cell immortalization.