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The vibration serviceability problems induced by the coupling vibration of lightweight footbridges is a research focus. Much research has been conducted in recent years, yet the attenuation of the coupling vibration subjected to a low-density crowd is still challenging. To investigate the coupling vibration between a moving crowd and aluminum alloy footbridge due to synchronous excitation, orthogonal crowd load tests were carried out on a simply supported aluminum alloy footbridge with a span of 34.8 m. Load tests with different numbers of pedestrians and step frequencies were conducted to obtain vibration frequency and peak acceleration of the footbridge. The comparative analysis reveals that vibration serviceability under certain conditions of synchronous excitation was not in accordance with German footbridges guidelines or British standards. Synchronous excitation of low-density crowds may lead to a marked decline in pedestrian comfort. A two degrees of freedom (TDOF) human dynamic model with a supporting mass of human body was applied to establish a crowd-footbridge coupling system. The numerical results are in agreement with experimental data, which validates the finite element model of the footbridge. Further numerical analysis was conducted to investigate the coupling vibration response of the footbridge subjected to low-density crowd below 1 person/m2. The results show that the coupling effect is minor when the mass ratio is 0.12–0.3. When the mass ratio is 0.3–0.46, the coupling vibration is significant. Therefore, the coupling vibration of lightweight aluminum alloy footbridge deserves attention in design when subjected to low-density crowds. The evaluation of vibration serviceability is advised to be conducted according to the requirements of peak acceleration given in footbridge specifications. [ABSTRACT FROM AUTHOR]

Simple Summary: Spodoptera frugiperda of the family Noctuidae in the order Lepidoptera, is native to the Americas. It is characterized by its polyphagous nature and high reproductive capacity. S. frugiperda has caused significant socio-economic losses in many countries, primarily affecting Poaceae crops such as maize, rice, wheat, and sorghum. This study aims to analyze the members, differentiation, structure, and function of the JHBP gene family in S. frugiperda through bioinformatics approaches. Subsequently, we utilize real-time quantitative PCR (qPCR) to investigate the expression profiles of this gene family across different developmental stages and various tissues of S. frugiperda. The purpose of this analysis is to elucidate the potential roles of these genes, providing key target genes for future functional validation through gene knockdown and RNA interference (RNAi) techniques. This research offers insights that could contribute to the development of new pesticides. Juvenile hormone binding proteins (JHBPs) are carrier proteins that bind to juvenile hormone (JH) to form a complex, which then transports the JH to target organs to regulate insect growth and development. Through bioinformatics analysis, 76 genes encoding JHBP in S. frugiperda were identified from whole genome data (SfJHBP1-SfJHBP76). These genes are unevenly distributed across 8 chromosomes, with gene differentiation primarily driven by tandem duplication. Most SfJHBP proteins are acidic, and their secondary structures are mainly composed of α-helices and random coils. Gene structure and conserved motif analyses reveal significant variations in the number of coding sequences (CDS) and a high diversity in amino acid sequences. Phylogenetic analysis classified the genes into four subfamilies, with a notable presence of directly homologous genes between S. frugiperda and S. litura, suggesting a close relationship between the two species. RNA-seq data from public databases and qPCR of selected SfJHBP genes show that SfJHBP20, SfJHBP50, and SfJHBP69 are highly expressed at most developmental stages, while SfJHBP8 and SfJHBP14 exhibit specific expression during the pupal stage and in the midgut. These findings provide a theoretical basis for future studies on the biological functions of this gene family. [ABSTRACT FROM AUTHOR]

Callose is widely present in higher plants and plays a significant role in plant growth, development, and response to various stresses. Although numerous studies have highlighted the importance of the callose synthase (CalS) genes, their role in the resistance of sorghum (Sorghum bicolor) to aphids (Melanaphis sacchari) remains limitedly understood. This study identified 11 sorghum callose synthase genes (SbCalS), unevenly distributed across four chromosomes of sorghum. All SbCalS proteins contain glucan synthase and Fks1 domains, with segmental duplication playing a major role in gene diversification. Cis-element prediction revealed the presence of numerous stress-responsive elements, indicating that this gene family is primarily involved in stress resistance. Using published RNA-seq data, we discovered the differential expression of the SbCalS5 gene between resistant and susceptible sorghum varieties. Real-time quantitative PCR (qPCR) analysis confirmed the relative expression levels of all SbCalS members under aphid stress. To further verify the role of callose in sorghum, we measured the callose content in both resistant and susceptible sorghum varieties. The results indicated that callose plays a critical role in aphid resistance in sorghum, particularly the SbCalS5 gene. This study provides a reference for further investigation into the role of callose synthase genes in sorghum aphid resistance. [ABSTRACT FROM AUTHOR]

Simple Summary: The sorghum aphid, a significant pest affecting sorghum cultivation in several continents, feeds primarily on sorghum leaves and stems by sucking sap. This feeding behavior results in the depletion of nutrients, sugars, and water in the plants, leading to inhibited growth, chlorosis, wilting, and ultimately death. The main objective of this study was to assess the stability of potential reference genes in the sorghum aphid (Melanaphis sacchari). Nine candidate reference genes underwent a rigorous selection process, and their reliability was evaluated using qRT-PCR Ct values. Various experiments were conducted to determine the best reference genes for the sorghum aphid through systematic stability analyses. The research offers a dependable collection of reference genes that can improve studies on gene expression and functional genomics related to the sorghum aphid. Appropriate reference genes must be selected for accurate qRT-PCR data to conduct a thorough gene expression analysis in the sorghum aphid (Melanaphis sacchari, Hemiptera, Aphididae). This approach will establish a foundation for gene expression analysis and determines the efficacy of RNA interference in the sorghum aphid. Nine potential reference genes, including Actin, 18S, GAPDH, RPL7, EF-1α, EF-1β, 28S, HSP70, and TATA, were assessed under various experimental conditions to gauge their suitability based on qRT-PCR Ct values. The stability of these candidate reference genes in diverse experimental setups was analyzed employing several techniques, including the ΔCt comparative method, geNorm, Normfinder, BestKeeper, and RefFinder. The findings revealed that the quantity of ideal reference genes ascertained by the geNorm method for diverse experimental conditions remained consistent. For the developmental stages of the sorghum aphid, RPL7 and 18S proved to be the most dependable reference genes, whereas GAPDH and EF-1β were recommended as the most stable reference genes for different tissues. In experiments involving wing dimorphism, EF-1α and GAPDH were identified as the optimal reference gene pair. Under varying temperatures, EF-1α and EF-1β were found to be the most dependable gene pair. For studies focusing on insecticide susceptibility, 18S and TATA emerged as the most stable candidate reference genes. Across all experimental conditions, EF-1α and EF-1β was the optimal combination of reference genes in the sorghum aphid. This research has pinpointed stable reference genes that can be utilized across various treatments, thereby enhancing gene expression studies and functional genomics research on the sorghum aphid. [ABSTRACT FROM AUTHOR]

Background/objectives: Chitinases, enzymes belonging to the glycoside hydrolase family, play a crucial role in plant growth and stress response by hydrolyzing chitin, a natural polymer found in fungal cell walls. This study aimed to identify and analyze the maize chitinase gene family, assessing their response to various biotic and abiotic stresses to understand their potential role in plant defense mechanisms and stress tolerance., Methods: We employed bioinformatics tools to identify 43 chitinase genes in the maize B73_V5 genome. These genes were characterized for their chromosomal positions, gene and protein structures, phylogenetic relationships, functional enrichment, and collinearity. Based on previous RNA-seq data, the analysis assessed the expression patterns of these genes at different developmental stages and under multiple stress conditions., Results: The identified chitinase genes were unevenly distributed across maize chromosomes with a history of tandem duplications contributing to their divergence. The ZmChi protein family was predominantly hydrophilic and localized mainly in chloroplasts. Expression analysis revealed that certain chitinase genes were highly expressed at specific developmental stages and in response to various stresses, with ZmChi31 showing significant responsiveness to 11 different abiotic and biotic stresses., Conclusions: This study provides new insights into the role of chitinase genes in maize stress response, establishing a theoretical framework for exploring the molecular basis of maize stress tolerance. The identification of stress-responsive chitinase genes, particularly ZmChi31, offers potential candidates for further study in enhancing maize resistance to environmental challenges.