Abstract
Utilization of rhizobacteria that have associated with plant roots in harsh environments could be a feasible strategy to deal with limits to agricultural production caused by soil salinity. ...Halophytes occur naturally in high-salt environments, and their roots may be associated with promising microbial candidates for promoting growth and salt tolerance in crops. This study aimed to isolate efficient halotolerant plant-growth-promoting rhizobacterial strains from halophytes and evaluate their activity and effects on sugar beet (Beta vulgaris L.) growth under salinity stress. A total of 23 isolates were initially screened for their ability to secrete 1-aminocyclopropane-1-carboxylate deaminase (ACD) as well as other plant-growth-promoting characteristics and subsequently identified by sequencing the 16S rRNA gene. Three isolates, identified as Micrococcus yunnanensis, Planococcus rifietoensis and Variovorax paradoxus, enhanced salt stress tolerance remarkably in sugar beet, resulting in greater seed germination and plant biomass, higher photosynthetic capacity and lower stress-induced ethylene production at different NaCl concentrations (50–125 mM). These results demonstrate that salinity-adapted, ACD-producing bacteria isolated from halophytes could promote sugar beet growth under saline stress conditions.
Investigation of the halotolerant plant-growth-promoting rhizobacteria from halophytes and the detection of their capacity to affect the salt tolerance of crops.
Two dimensional atomic crystals with pentagonal building blocks have attracted extensive interest in recent years for their fundamental significance and potential applications in nanoscale devices. ...Here, with the help of ab initio calculations based on density functional theory, we report a unique pentagonal structured NiS2 monolayer in P421m symmetry, named P-NiS2. Its dynamic stability has been confirmed by phonon mode analysis. Molecular dynamics simulations and total-energy calculations show that this new P-NiS2 has robust thermal stability and energetically more stable than all other reported NiS2 monolayer structures. Electronic band structure calculations show that it is a semiconductor with an indirect band gap of 1.94 eV. Furthermore, we find that small strain triggers a transition from the indirect to direct band gap for this P-NiS2, suggesting its great potential for applications based on strain-engineering techniques.
Many approaches to engineer source strength have been proposed to enhance crop yield potential. However, a well-co-ordinated source–sink relationship is required finally to realize the promised ...increase in crop yield potential in the farmer’s field. Source–sink interaction has been intensively studied for decades, and a vast amount of knowledge about the interaction in different crops and under different environments has been accumulated. In this review, we first introduce the basic concepts of source, sink and their interactions, then summarize current understanding of how source and sink can be manipulated through both environmental control and genetic manipulations. We show that the source–sink interaction underlies the diverse responses of crops to the same perturbations and argue that development of a molecular systems model of source–sink interaction is required towards a rational manipulation of the source–sink relationship for increased yield. We finally discuss both bottom-up and top-down routes to develop such a model and emphasize that a community effort is needed for development of this model.
Key parts refer to the problematic parts which have higher carbon emissions and need to be further optimized in low-carbon design. However, it is difficult to pick them out for designers because the ...quantitative relationship and unified connection between product life cycle stages and carbon emissions are hard to determine. To efficiently and effectively select the key parts of equipment products, this paper presents a selection methodology based on the characteristic of carbon emissions for low-carbon design. First, a low-carbon design framework is constructed to guide the low-carbon design process. Second, an embodied carbon-energy field (ECEF)-based selection method is proposed to help product designers make a decision. The ECEF denotes the carbon emissions distribution on product structures. Based on the temperature field of products, the ECEF can be constructed by integrating the main life cycle stages of products. The definition of ECEF is given initially. Then, the mapping mechanism and process between the temperature field and ECEF are studied. Meanwhile, the mathematical model of the ECEF is also presented to support the mapping process. Thus, the total carbon emissions distribution of every part and every point can be achieved by the ECEF of products and also seen by product designers visually. Therefore, the key parts could be selected easily. Finally, the proposed method is applied to a CNC gantry type honing machine to validate its feasibility and correctness. The result shows the selection method can be used to identify the problematic parts and points effectively and easily.
Batch manufacturing has attracted extensive attention as a crucial way in process industry. It has typical wide-range nonstationary characteristics subject to time variant conditions, not only within ...each batch but also for different batches. The presence of closed-loop control complicates the task of batch process monitoring which shows that closed-loop control can significantly alter the process characteristics with both static deviations and varying temporal correlations. It is of a considerable challenge for batch process analysis and monitoring under closed-loop control which may work quite unlike that under open-loop control. In this article, a fine-scale process modeling and monitoring method are developed with dynamics analytics for wide-range nonstationary batch manufacturing with duration uncertainty. Both static and dynamic monitoring statistics are designed with clear physical interpretation which can work together to achieve fine-scale batch process status identification and monitoring. On one hand, it can identify frequent normal switching of operation status at different time by simultaneously checking both static and dynamic deviations regulated by closed-loop control. On the other hand, it can detect small disturbances in early stage where the impact may be overshadowed by the regulation of closed-loop controllers, making faults difficult to detect in time by conventional methods. Experiments have shown the validity of the proposed fine-scale monitoring method for wide-range batch process.
Since 2019, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) causing coronavirus disease 2019 (COVID‐19) has infected 10 millions of people across the globe, and massive mutations in ...virus genome have occurred during the rapid spread of this novel coronavirus. Variance in protein sequence might lead to a change in protein structure and interaction, then further affect the viral physiological characteristics, which could bring tremendous influence on the pandemic. In this study, we investigated 20 nonsynonymous mutations in the SARS‐CoV‐2 genome in which incidence rates were all ≥ 1% as of September 1st, 2020, and then modeled and analyzed the mutant protein structures. The results showed that four types of mutations caused dramatic changes in protein structures (RMSD ≥ 5.0 Å), which were Q57H and G251V in open‐reading frames 3a (ORF3a), S194L, and R203K/G204R in nucleocapsid (N). Next, we found that these mutations also affected the binding affinity of intraviral protein interactions. In addition, the hot spots within these docking mutant complexes were altered, among which the mutation Q57H was involved in both Orf3a–S and Orf3a–Orf8 protein interactions. Besides, these mutations were widely distributed all over the world, and their occurrences fluctuated as time went on. Notably, the incidences of R203K/G204R in N and Q57H in Orf3a were both over 50% in some countries. Overall, our findings suggest that SARS‐CoV‐2 mutations could change viral protein structure, binding affinity, and hot spots of the interface, thereby might have impacts on SARS‐CoV‐2 transmission, diagnosis, and treatment of COVID‐19.
Two-parameter Weibull function has been widely applied to evaluate wind energy potential. In this paper, six kinds of numerical methods commonly used for estimating Weibull parameters are reviewed; ...i.e. the moment, empirical, graphical, maximum likelihood, modified maximum likelihood and energy pattern factor method. Their performance is compared through Monte Carlo simulation and analysis of actual wind speed according to the criterions such as Kolmogorov–Smirnov test, parameter error, root mean square error, and wind energy error. The results show that, in simulation test of random variables, the graphical method’s performance in estimating Weibull parameters is the worst one, followed by the empirical and energy pattern factor methods, if data number is smaller. The performance for all the six methods is improved while data number becomes larger; the graphical method is even better than the empirical and energy pattern factor methods. The maximum likelihood, modified maximum likelihood and moment methods present relatively more excellent ability throughout the simulation tests. From analysis of actual data, it is found that if wind speed distribution matches well with Weibull function, the six methods are applicable; but if not, the maximum likelihood method performs best followed by the modified maximum likelihood and moment methods, based on double checks including potential energy and cumulative distribution function.
The use of synthetic bridges as surrogates for disulfide bonds has emerged as a practical strategy to obviate the poor stability of some disulfide‐containing peptides. However, peptides incorporating ...large‐span synthetic bridges are still beyond the reach of existing methods. Herein, we report a native chemical ligation (NCL)‐assisted diaminodiacid (DADA) strategy that enables the robust generation of disulfide surrogate peptides incorporating surrogate bridges up to 50 amino acids in length. This strategy provides access to some highly desirable but otherwise impossible‐to‐obtain disulfide surrogates of bioactive peptide. The bioactivities and structures of the synthetic disulfide surrogates were verified by voltage clamp assays, NMR, and X‐ray crystallography; and stability studies established that the disulfide replacements effectively overcame the problems of disulfide reduction and scrambling that often plague these pharmacologically important peptides.
A native‐chemical‐ligation‐assisted diaminodiacid strategy was developed for the chemical synthesis of peptide disulfide surrogates, forming ring sizes of up to 50 amino acids. The method can facilitate the engineering of biologically interesting disulfide‐containing peptides, and may widen the horizon of peptide‐based research tools and diagnostic or therapeutic reagents.
Background. Researchers are highly interested in the study of nonspecific low back pain (NSLBP). However, few have attempted to collect global data, analyze the emerging trends, and conduct reviews ...from the perspectives of visualization and bibliometrics. Purpose. We aimed to evaluate research situation and capture subsequent developmental dynamics regarding NSLBP via CiteSpace. Methods. Publications on NSLBP in recent 19 years were retrieved from the Web of Science Core Collection (WoSCC). We used CiteSpace to analyze publication outputs, document types, countries, institutions, journals, authors, references, and keywords. Knowledge foundation, hot topics, and future direction were then stated. Results. A total of 1099 papers were collected, and the trend of annual publications maintained growth with small fluctuations. Australia (188) and the University of Sydney (76) were the most prolific country and institution, respectively. The Netherlands (0.84) and the University of Sydney (0.47) had the maximum centrality, thus indicating that they have importance in this field. The journal Spine (publication: 87, cocitation counts: 942) ranked first in terms of the volume of publications and cocitation counts. Maher CG (52) who published the most papers and Waddell G (286) who was cited most frequently were the leading authors, thus making strong academic influences. “Motor control exercise” was the largest cluster, which contained most related research articles. 14 references with the strongest citation counts were cited until 2018, thus implying the future development trend. Current hotspots were treatment, meta-analysis, method, and risk factors. Spine, efficacy, adult, and meta-analysis can be regarded as research frontiers. Conclusion. This study offers insights into the trend of NSLBP to determine major research countries and institutions, core journals, pivotal authors, overall development tendency, hot topics, and research frontiers. Moreover, it will help researchers extract hidden valuable information for further study.
While saline soils account for 6.5% of the total land area globally, it comprises about 70% of the area in northwestern China. Microbiota in these saline soils are particularly important because they ...are critical to maintaining ecosystem services. However, little is known about the microbial diversity and community composition in saline soils. To investigate the distribution patterns and edaphic determinants of bacterial communities in saline soils, we collected soil samples across the hypersaline Ebinur Lake shoreline in northwestern China and assessed soil bacterial communities using bar-coded pyrosequencing. Bacterial communities were diverse, and the dominant phyla (>5% of all sequences) across all soil samples were Gammaproteobacteria, Actinobacteria, Firmicutes, Alphaproteobacteria, Bacteroidetes and Betaproteobacteria. These dominant phyla made a significant (P < 0.05) contribution to community structure variations between soils. Halomonas, Smithella, Pseudomonas and Comamonas were the indicator taxa across the salinity gradient. Bacterial community composition showed significant (P < 0.05) correlations with salt content and soil pH. Indeed, bacterial phylotype richness and phylogenetic diversity were also higher in soils with middle-level salt rates, and were significantly (P < 0.05) correlated with salt content and soil pH. Overall, our results show that both salinity and pH are the determinants of bacterial communities in saline soils in northwest China.
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