Well-posedness and regularity of the Darcy-Boussinesq system in layered porous media

We investigate the Darcy-Boussinesq model for convection in layered porous media. In particular, we establish the well-posedness of the model in two and three spatial dimension, and derive the regularity of the solutions in a novel piecewise H2 space

Intensified Pulse Rotations Buildup Pea Rhizosphere Pathogens in Cereal and Pulse Based Cropping Systems

The association of plants and microbial communities is crucial for crop production, and host plants influence the composition of rhizosphere microbiomes. Pulse crops play an important role in the development of sustainable cropping systems, and producers in the Canadian prairies often increase the frequency of pulses in their cropping systems. In this study, we determined the shifts in the fungal community of pea (Pisum sativum L.) rhizosphere, as influenced by the frequency of pulses in rotation, using high throughput sequencing. Six cropping systems containing pea (P), lentil (Lens culinaris Medik., L), hybrid canola (Brassica napus L., C), wheat (Triticum aestivum L., W), and oat (Avena sativa L., O) in different intensities were tested. The fungal communities were assessed at the flowering stage in the fourth and fifth year of the 4-year rotations. Cropping system had a significant impact on the composition of the rhizosphere fungal community, and the effect of crop rotation sequence was greater and explained more of the variation than the effect of previous crops. The rotation with consecutive pulses (WPLP) decreased fungal evenness and increased the proportion of pathotrophs. Fusarium was a dominant and ubiquitous pathotrophic genus. Olpidium virulentus, Botrytis cinerea, Fusarium solani, F. graminearum, and Alternaria eichhorniae were generally more abundant in pulse intensive rotations (WPLP, WLOP, and WPOP), the exception being F. solani which was not promoted by lentil. Reads of O. virulentus and B. cinerea were most abundant in pea preceded by lentil followed by the reads of Mortierella elongata in pea preceded by wheat. Pea consistently had higher grain yield when grown in diversified rotations including wheat, canola/lentil, and oat than rotations with two repeated crops (canola or pea). Cropping system affected the soil physicochemical properties, and soil pH was the main driver of fungal community shift. No evidence of beneficial microorganisms involvement in plant productivity was observed, but the high abundance of pathotrophs in pulse intensified rotations suggests the possibility of pathogen buildup in the soil with increasing pulse frequency. Diversifying rotation sequences minimized disease risk and increased pea production, in this study. Careful selection of plant species appears as a strategy for the management of rhizosphere fungal communities and the maintenance of crop production system’s health

Epidemiological characteristics of respiratory viruses in hospitalized children during the COVID-19 pandemic in southwestern China

BackgroundMultinational studies have reported that the implementation of nonpharmaceutical interventions (NPIs) to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission coincided with the decline of other respiratory viruses, such as influenza viruses and respiratory syncytial virus.ObjectiveTo investigate the prevalence of common respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic.MethodsRespiratory specimens of children with lower respiratory tract infections (LRTIs) hospitalized at the Children’s Hospital of Chongqing Medical University from January 1, 2018 to December 31, 2021 were collected. Seven common pathogens, including respiratory syncytial virus (RSV), adenovirus (ADV), influenza virus A and B (Flu A, Flu B), and parainfluenza virus types 1–3 (PIV1–3), were detected by a multiplex direct immunofluorescence assay (DFA). Demographic data and laboratory test results were analyzed.Results1) A total of 31,113 children with LRTIs were enrolled, including 8141 in 2018, 8681 in 2019, 6252 in 2020, and 8059 in 2021.The overall detection rates decreased in 2020 and 2021 (P < 0.001). The detection rates of RSV, ADV, Flu A, PIV-1, and PIV-3 decreased when NPIs were active from February to August 2020, with Flu A decreasing most predominantly, from 2.7% to 0.3% (P < 0.05). The detection rates of RSV and PIV-1 resurged and even surpassed the historical level of 2018–2019, while Flu A continued decreasing when NPIs were lifted (P < 0.05). 2) Seasonal patterns of Flu A completely disappeared in 2020 and 2021. The Flu B epidemic was observed until October 2021 after a long period of low detection in 2020. RSV decreased sharply after January 2020 and stayed in a nearly dormant state during the next seven months. Nevertheless, the detection rates of RSV were abnormally higher than 10% in the summer of 2021. PIV-3 decreased significantly after the COVID-19 pandemic; however, it atypically surged from August to November 2020.ConclusionThe NPIs implemented during the COVID-19 pandemic affected the prevalence and seasonal patterns of certain viruses such as RSV, PIV-3, and influenza viruses. We recommend continuous surveillance of the epidemiological and evolutionary dynamics of multiple respiratory pathogens, especially when NPIs are no longer necessary

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Transcriptomic and Metabolic Profiling Reveals a Lignin Metabolism Network Involved in Mesocotyl Elongation during Maize Seed Germination

Lignin is an important factor affecting agricultural traits. The mechanism of lignin metabolism in maize (Zea mays) mesocotyl elongation was investigated during seed germination. Maize seeds were treated with 24-epibrassinolide (EBR) and brassinazole stimulation under 3 and 20 cm deep-seeding stress. Mesocotyl transcriptome sequencing together with targeted metabolomics analysis and physiological measurements were employed in two contrasting genotypes. Our results revealed differentially expressed genes (DEGs) were significantly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, flavonoid biosynthesis, and alpha-linolenic acid metabolism. There were 153 DEGs for lignin biosynthesis pathway, 70 DEGs for peroxisome pathway, and 325 differentially expressed transcription factors (TFs) of MYB, NAC, WRKY, and LIM were identified in all comparisons, and highly interconnected network maps were generated among multiple TFs (MYB and WRKY) and DEGs for lignin biosynthesis and peroxisome biogenesis. This caused p-coumaraldehyde, p-coumaryl alcohol, and sinapaldehyde down-accumulation, however, caffeyl aldehyde and caffeyl alcohol up-accumulation. The sum/ratios of H-, S-, and G-lignin monomers was also altered, which decreased total lignin formation and accumulation, resulting in cell wall rigidity decreasing. As a result, a significant elongation of maize mesocotyl was detected under deep-seeding stress and EBR signaling. These findings provide information on the molecular mechanisms controlling maize seedling emergence under deep-seeding stress and will aid in the breeding of deep-seeding maize cultivars

Transcriptomic and Metabolic Profiling Reveals a Lignin Metabolism Network Involved in Mesocotyl Elongation during Maize Seed Germination

Lignin is an important factor affecting agricultural traits. The mechanism of lignin metabolism in maize (Zea mays) mesocotyl elongation was investigated during seed germination. Maize seeds were treated with 24-epibrassinolide (EBR) and brassinazole stimulation under 3 and 20 cm deep-seeding stress. Mesocotyl transcriptome sequencing together with targeted metabolomics analysis and physiological measurements were employed in two contrasting genotypes. Our results revealed differentially expressed genes (DEGs) were significantly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, flavonoid biosynthesis, and alpha-linolenic acid metabolism. There were 153 DEGs for lignin biosynthesis pathway, 70 DEGs for peroxisome pathway, and 325 differentially expressed transcription factors (TFs) of MYB, NAC, WRKY, and LIM were identified in all comparisons, and highly interconnected network maps were generated among multiple TFs (MYB and WRKY) and DEGs for lignin biosynthesis and peroxisome biogenesis. This caused p-coumaraldehyde, p-coumaryl alcohol, and sinapaldehyde down-accumulation, however, caffeyl aldehyde and caffeyl alcohol up-accumulation. The sum/ratios of H-, S-, and G-lignin monomers was also altered, which decreased total lignin formation and accumulation, resulting in cell wall rigidity decreasing. As a result, a significant elongation of maize mesocotyl was detected under deep-seeding stress and EBR signaling. These findings provide information on the molecular mechanisms controlling maize seedling emergence under deep-seeding stress and will aid in the breeding of deep-seeding maize cultivars

Identification of stress-related characteristics of the WRKY gene family: A case study of Dendrobium catenatum

As one of the largest families of transcription factors (TFs) in plants, the WRKY TF family plays a key role in regulating plant responses to various biotic and abiotic stresses. However, there is no confirmed method to quickly identify stress-responsive members from the WRKY gene family. In this study, all reported functional WRKY genes were first analyzed, and the amino acid patterns in response to stress were identified in group II-c (T-R/K-S/T-E/Q/D-V/I/L-E/D-I/V/H/N-L/M-D/E-D-G/E-F/Y-K/R-WRKYG-Q/K-K-A/T-VKN-S/N-P), group II-d (VPA-I/V-S-X-K-M/L/V/I-ADIP-P/A/V-D-D/E-Y/F-S-WRKYGQKPIKGSP-H/Y-PRGYYKCS-S/T-V/M-RGCPARKVER), and group II-e (PSD-S/A/L-WAWRKYGQKPIKGSPYPR-G/S-YYRCSSSKGC). WRKY genes in Dendrobium catenatum were used to validate the accuracy of these patterns. A total of 63 DcaWRKY genes were identified, their gene structures, conserved motifs, and gene expression patterns were analyzed, and a phylogenetic tree was constructed. Gene expression patterns were then analyzed under drought stress, and seven DcaWRKY genes (Dca002550, Dca002715, Dca005648, Dca007842, Dca010430, Dca016437, and Dca006787) were randomly selected to determine their expression levels and verify their expression patterns by quantitative real-time polymerase chain reaction analysis. The identified amino acid patterns were validated by drought-responsive WRKY genes in D. catenatum, confirming the accuracy of these amino acid patterns and providing valuable insights into further research of the WRKY family in D. catenatum

Soil residual water and nutrients explain about 30% of the rotational effect in 4-year pulse-intensified rotation systems

Diverse crop rotations enable the best use of residual soil water and nutrients, thus, decreasing production inputs. Here, we determined the effect of cropping sequences on soil residual water and nutrients, and the performance of subsequent wheat (Triticum aestivum L.). Nine rotation systems were evaluated at Swift Current, Saskatchewan, and Brooks, Alberta, from 2010 to 2014. Pea (P) (Pisum sativum L.) and lentil (L) (Lens culinaris Medik.) as preceding crops before wheat (W) or the rotation systems with pea (PPPW) or lentil (LLLW) included more than once in the 4-yr rotations had the highest residual soil water and N in the 30-90 cm depths, and continuous wheat (WWWW) had the lowest. Preceding pea and lentil increased the grain yield of the subsequent wheat by 26% and 18%, respectively, as compared with the continuous wheat. Variance partitioning of redundancy analysis revealed that soil residual water and residual N explained 12.4 to 42.7% (average 30%) of the yield variation observed in the subsequent wheat, with the rest of the rotational benefits unexplainable by soil residual water and residual nutrients. Investigation of the factors other than soil water and nutrients that contribute to the succeeding wheat yield may further enhance the rotational effect.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author