Freshwater Gammarus species represent important keystone organisms in aquatic ecosystems, and are sensitive to environmental changes. Here, we present the first pseudo-chromosome-level genome of Gammarus nekkensis, endemic to north China. We integrated PacBio HiFi long-read sequencing, Illumina short-read sequencing, and Hi-C scaffolding to generate a high-quality, pseudo-chromosome-scale genome assembly. The assembled genome is approximately 6.24 Gb in size, with a scaffold N50 of 233.63 Mb, and 96.76% of the sequences were successfully anchored to 26 pseudo-chromosomes. A total of 39,474 protein-coding genes were predicted, and approximately 70% of these genes obtained functional annotations. Repetitive elements constituted about 63.93% of the genome, with long interspersed nuclear elements (LINE) being the most abundant (23.98%). BUSCO analysis indicated that both the assembly and annotation are highly complete compared with published amphipod genomes. This high-quality genome enables studies of sex determination, adaptive evolution, and genomic diversity in G. nekkensis, with applications for its conservation and breeding.

ABSTRACT Spodoptera frugiperda poses a significant threat as a polyphagous agricultural pest. Autographa californica multiple nucleopolyhedrovirus (AcMNPV), a broad-spectrum baculovirus with established activity against multiple lepidopteran pests, represents an environmentally benign biocontrol candidate. However, its efficacy against S. frugiperda is constrained by limited oral infectivity. Here, serial passaging in S. frugiperda yielded a mutant strain of AcMNPV (AcMNPV-Mut) with significantly enhanced oral infectivity relative to the wild strain AcMNPV (AcMNPV-Wt). Importantly, while both oral infectivity and overall virulence (shortened LT₅₀ and increased mortality) against S. frugiperda were enhanced, the virus maintained its ability to effectively infect and cause disease in other insect hosts, like Helicoverpa armigera. Whole-genome sequencing identified a missense mutation in ac34. Functional characterization of a recombinant virus harboring this mutation revealed that the ac34 variant contributes to virulence augmentation through dual pathways: elevated budded viruses (BVs) production facilitating secondary infection, and upregulated late and very late gene expression, which improves occlusion-derived virus (ODV) embedding within occlusion bodies (OBs), and may lead to an increase in OB size, contributing to a higher viral load per particle, and thereby enhancing primary infectivity. The ac34 mutation enhances primary and secondary infection, promoting virulence evolution and providing a molecular target for biopesticide design.IMPORTANCEIn this study, we found that Autographa californica multiple nucleopolyhedrovirus (AcMNPV) undergoes adaptive mutations after serial passages in the semi-permissive host Spodoptera frugiperda, driven by mutation in ac34. These mutations not only significantly increase viral replication within this pest but also improve the packaging and infectivity of viral particles. This coordinated optimization allows the virus to achieve higher effective doses in a short time, synergistically enhancing its control efficiency against S. frugiperda. Importantly, the mutation does not compromise the virus’s pathogenicity toward its original permissive hosts, underscoring its potential utility in single-application strategies for integrated pest management. These findings provide new molecular insights for designing efficient and broadly applicable biocontrol agents, contributing to more sustainable management of agricultural pests and reduced reliance on chemical pesticides.

Stress-associated proteins (SAPs) are zinc finger proteins involved in the regulation of various stresses in a variety of plant species. Less is known about their characteristics and molecular functions in Dendrobium officinale, which is a traditional Chinese medicinal herb. Here, 18 DoSAPs with conserved zinc-binding motifs were identified in D. officinale. The phylogenetic analysis of these proteins and their orthologs from Arabidopsis and rice indicated that they can be classified into six of the nine groups within the SAP gene family. Genes within the same group exhibit similar structures and conserved domains. An examination of the cis-acting elements in the DoSAP promoters identified numerous elements related to stress and plant hormones, particularly those responsive to light. Predictive modeling of the three-dimensional structures and ligand-binding sites of DoSAP proteins revealed that most possess the typical Cys2His2 zinc finger motif. High-throughput RNA-seq data showed that DoSAP gene profiles differed among various tissues. Furthermore, DoSAP gene expression is altered in response to various stresses (salt, drought, heat, cold and light) and phytohormone treatments (GA, ABA), suggesting that the transcriptional regulation of DoSAP genes may play a crucial role, especially in their significant response to light treatment. Notably, DoSAP3 (light/salt stress), DoSAP4 (different tissues/growth), DoSAP8 (temperature stress) exhibit significantly high expression. This investigation systematically characterized DoSAP genes and laid a solid foundation for understanding their functional diversification in mediating D. officinale's adaptation to environmental stresses responses.

The fall armyworm (Spodoptera frugiperda) is a major global migratory pest. Its increasing insecticide resistance poses a severe threat to food security. Developing biopesticides such as SfMNPV is critical for sustainable control. Nevertheless, the early molecular mechanisms underlying the S. frugiperda midgut response to oral SfMNPV challenge remain poorly understood. This study utilized high-throughput transcriptome sequencing to systematically characterize the dynamic transcriptional profiles of the larval midgut at 1, 12, and 24 h after oral SfMNPV inoculation. Results showed that the midgut transcriptional response to SfMNPV is time and stage-specific. During this period, the physical midgut barrier underwent remodeling, with core components of the peritrophic matrix downregulated at 1 h, followed by the basal lamina at 12 h, alongside the activation of cytoskeleton genes during 12-24 h. Concurrently, sustained endoplasmic reticulum stress, autophagy, and ubiquitin system responses occurred from 12 to 24 h. At the metabolic level, the defense system exhibited a functional succession, shifting from ABC transporters and UDP-glycosyltransferases at 1 h to glutathione S-transferases and superoxide dismutase at 12-24 h. Additionally, the midgut tissue exhibited a cascade transition from pro-apoptotic signaling at 1 h to compensatory regenerative repair mediated by the Wnt, mTOR, and Hippo pathways at 12-24 h. This study elucidates the molecular process of barrier damage, homeostatic imbalance, and tissue remodeling during early oral SfMNPV challenge. These findings provide a global perspective on baculovirus-host interactions and establish a theoretical foundation for designing novel biopesticides targeting the midgut interaction.

In the past two decades, some shallow-buried urban road tunnels with shafts (URTS) have been built and operated in large cities in China, and successfully released the traffic congestion. However, uncertainties of fire smoke exhausting and individual safety have still been worried. Here, an idea of installing and operating the axial exhaust fans inside the unit shafts near to the fire source is proposed, then a hybrid ventilation is formed that combines both natural and mechanical ventilation. Three sets of full-scale fire experiments were carried out on a real URTS in Nanjing China. A 1.6 m (length) x 1.6 m (width) pan was placed on the ground in middle of the 264 m longest buried section. Diesel oil was used as the fire source. Fire 1 was conducted in a hot summer under pure natural ventilation without fan working. Fires 2 and 3 were conducted in a cold winter respectively without and with three SHANGFENG HTF-II-5.5C fans working. Smoke parameters of temperature, velocity and CO concentration were recorded by monitors respectively under the ceiling, inside the shafts, on the shaft tops and at the shaft bottoms. Inhibition coefficient f(i) is proposed to evaluate the influence of the fans working on the smoke flow of those non-fanned shafts. Results show that the dual power-law exponent function provided a better fit for the ceiling temperature decay, and the decay coefficients ranged from 0.042 to 0.069 with the sortation: Fire 2 > Fire 3 > Fire 1. On top openings of the shafts, parameters reached up to 47 degrees C in temperature, 4.6 m/s in velocity, and 120 ppm in CO concentration. Mass flow rates of the unit shafts differed in range of 0.24 similar to 2.03 kg/(s.m(2)) that decreased away from the fire sources in Fires 1 and 2, but increased away from the fanned-shafts in Fire 3. Wang model provides a better similar result to that under measurement. The coefficients f(i) ranged from -0.5 to 1.29. The fan operations did promote the smoke discharge of the non-fanned shafts close tightly to the fanned shafts, but reduce the discharge some far away from the fanned shafts. This study provides on-site data in URTS firing, and ascertains the useful of operating the shaft axial fans in promoting the smoke control.

The design of highly electron-active and stable heterogeneous catalysts for ambient nitrogen reduction reaction is challenging due to the inertness of N2 molecule. Herein, we designed and synthesized the first zinc-based coordination polymer with bridging dinitrogen anion ligand, namely NJUZ-1, which is an efficient photocatalyst for atmospheric nitrogen fixation, exhibiting an outstanding ammonia conversion rate of 140 μmol g−1 h−1 and functioning well even with unpurified air as feeding gas. Experimental and theoretical studies revealed that the active “Zn2+-(N≡N)−1-Zn2+” sites can promote the formation of NH3, and the detachment of the yielded NH3 creates unsaturated “Zn2+···Zn+” intermediates, which can be replenished again by external N2 sequestration and fast intermolecular electron migration. The “Zn2+···Zn+” intermediates stabilized by the sandwiched cage-like donor-acceptor-donor framework can sustain continuous catalytic cycles via a pathway analogous to the Mars-van Krevelen process. This work presents a conceptually new strategy for nitrogen fixation via molecular active site catalysts based on metal complexes under mild conditions.

Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), belonging to the species Alphabaculovirus spofrugiperdae, has been recently registered as an insecticide in China. This virus has a specific effect on the global major agricultural pest Spodoptera frugiperda. To gain insights into viral infection, replication processes, and the complex formation of viral particles, in vitro studies using cell lines are essential tools. Although the IPLB-Sf9 and IPLB-Sf21 cell lines derived from S. frugiperda are widely used for studies on the infection and replication mechanisms of Autographa californica multiple nucleopolyhedrovirus (AcMNPV), their capacity to produce viral polyhedra after SfMNPV infection is not optimal. To address this limitation, a novel cell line named IOZCAS-Sf-1 was developed from a S. frugiperda population in Yunnan, China. The mitochondrial COX1 gene analysis confirmed the species origin of the IOZCAS-Sf-1 cell line. Furthermore, a comparative study was carried out to contrast the COX1 gene sequence of this novel cell line with that of IPLB-Sf9, highlighting the distinctions between the two. Importantly, the IOZCAS-Sf-1 cells exhibited a remarkable ability to generate polyhedra when infected with AcMNPV and SfMNPV, respectively. Consequently, this cellular lineage is considered a promising and valuable resource. It serves not only to investigate the molecular mechanisms of viral replication and its impact on host cells, but also to explore the transfection efficiency of SfMNPV DNA. This exploration further expands into its potential application in recombinant DNA experiments, laying a theoretical groundwork for the advancement of more effective biopesticides and sustainable agricultural practices.

Abstract Background Previous studies have shown that gut microbiota (GM) are associated with gestational diabetes mellitus (GDM). Although it is unclear if the association is causative. This study used Mendelian randomization (MR) to systematically examine whether the gut microbiota was causally linked to GDM .There have been numerous Mendelian randomization (MR) studies that between the gut microbiota abundance (genus) and gestational diabetes mellitus (GDM). However, the gut microbiota abundance(family, orders, classes,and phyla)have yet to be fully investigated.This study used Mendelian randomization (MR) to systematically examine whether several gut microbiota taxa was causally linked to GDM. Methods Genetic instrumental variables for the gut microbiota were identified from a genome-wide association study (GWAS) involving 14306 participants. Summary statistics for gestational diabetes mellitus(GDM)were drawn from another GWAS, which included 6033 cases and 110330 controls.Maximum likelihood (ML), MR-Egger regression, weighted median, inverse variance weighted(IVW), and weighted model were used to investigate the causal association between gut microbiota and GDM. To examine the causal association, several methods were utilized, including inverse variance weighted, maximum likelihood, weighted median, MR-Egger, and MR.RAPS. We further conducted a series of sensitivity analyses to confirm the robustness of the primary results of the MR analyses.Reverse MR analysis was performed on the bacterial taxa that were reported to be causally linked to GDM risk in forwarding MR analysis to evaluate the possibility of reverse causation. Furthermore, sensitivity analyses were performed to identify any potential heterogeneity and horizontal pleiotropy. Results MR analysis revealed that phylum Tenericutes (OR: 0.717 95%CI: 0.573–0.896, P = 0.003), class Mollicutes (OR: 0.717, 95%CI: 0.573–0.896, P = 0.003)were related to a lower risk of GDM, and family Lactobacillaceae(OR: 1.303, 95%CI: 1.001–1.697, P = 0.049)were positively associated with the risk of GDM. Additional sensitivity analyses confirmed the robustness of the association between specific gut microbiota composition and GDM. In the reverse Mendelian randomization (MR) analysis, we did not find evidence that these was statistically significant associations between GDM and these three bacterial traits. Conclusions Our systematic analysis provides evidence to explore the causal associations among GM and GDM. More studies are needed to clarify how the gut microbiota(family, orders, classes,and phyla) affects the development of GDM.

BACKGROUND AND AIMS:In response to documented duodenoscope-related infectious outbreaks of multidrug-resistant organisms, the Food and Drug Administration has recommended a transition to duodenoscopes with innovative designs, including duodenoscopes with disposable components or fully disposable duodenoscopes. We aim to characterize the learning curve (LC) for a single-use disposable duodenoscope.METHODS:We performed a retrospective analysis of a prospectively collected database from 31 patients who underwent ERCP by a single, experienced operator using the EXALT Model D® (Boston Scientific, Marlborough) disposable duodenoscope at a single tertiary referral center. The LC for this device was described by the number of cases needed to achieve proficiency using cumulative sum (CUSUM) analysis. Number of attempts to cannulate and time to cannulate the desired duct were assessed as separate endpoints. The overall mean number of attempts and overall mean time to cannulation were used as the target values in the respective CUSUM analyses. Proficiency was defined as the number of procedures where an inflection point was reached in the CUSUM graph. This observation indicates improving operator performance as shown by a decrease in the number of attempts and shortening of cannulation time after the defined number of procedures.RESULTS:Overall, 31 patients underwent ERCP using the EXALT Model D disposable duodenoscope by a single experienced endoscopist. 6 (19%) patients had a native papilla and the majority of these procedures were classified as ASGE complexity level 2 or above. The procedure was completed using solely the disposable duodenoscope in 27 patients (87%), while a reusable duodenoscope was required for procedure completion in 4 patients (13%). The cross-overs were distributed evenly across the performance period. Procedure-related adverse events included: post-ERCP pancreatitis (3%), bleeding (3%) and no perforations. In the analyses of both endpoints, an inflection of the CUSUM curves is achieved at 10 cases, indicating sustained reduction of cannulation attempts and time to cannulation.CONCLUSION:Among experienced pancreaticobiliary endoscopists, approximately 10 ERCPs is the threshold whereby procedure-related factors including cannulation success and procedural time improves. Procedure-related adverse events are consistent with those expected with reusable duodenoscopes. The need to cross-over from single-use duodenoscope to reusable duodenoscope did not appear to be related to the learning curve, as they were evenly distributed across the study period. These results can be used to guide adoption of single-use duodenoscopes into clinical practice.

As a commonly used first-line targeted drug, imatinib (Ima) is widely used first-line treatment for cancer patients. Patient survival is significantly prolonged, but Ima can cause premature ovarian failure (POF) and affect fertility. However, the underlying mechanism is unknown, and no effective method can be employed to improve this process. To investigate the effect of quercetin (Que) on Ima-induced POF and the underlying mechanism. The therapeutic impact of Que on Ima-induced POF in mice was clarified via molecular biology experiments and in vivo experiments in animals. To verify the underlying mechanism, network pharmacology was employed to construct a signaling network of Que-Ima-POF-related genes, followed by molecular biology and docking analysis. Network pharmacology analysis identified 38 therapeutic targets of Que in Ima-induced POF. The KEGG pathways of these genes were enriched for the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Molecular docking analysis revealed that the epidermal growth factor receptor (EGFR) is a shared target of Que, Ima, and POF and has strong binding affinity. Hematoxylin-eosin (HE) staining and ELISA confirmed that Que can partially restore the ovarian index and function of mice with Ima-induced POF. Western blot, TUNEL, and immunohistochemical staining confirmed that Que promoted the PI3K/Akt signaling pathway and reduced apoptosis in Ima-induced POF mice. Thus, Que could inhibit apoptosis in Ima-induced POF by activating the PI3K/Akt pathway.

Purpose: Exercise has a positive regulatory effect on gut microbiota and is also involved in regulating multiple physiological functions of the human body. This article tested the effects of basketball exercises at different exercise intensities on the gut microbiota of college students. Methods: Athlete research subjects (male, aged 18 - 25) were selected from the basketball team and trained at different intensities to obtain a total of 101 fresh fecal samples. DNA was extracted by a DNA extraction kit and bacterial 16S rRNA gene V3-V4 region high-throughput sequencing using the Illumina Hiseq platform. The downstream data were spliced, filtered and de-trimerized and then used to study the difference in gut microbiota. Results: Key bacterial taxa in the gut that responded to exercise intensity differed among athletes of different exercise intensities but most belonged to Firmicutes. With increasing exercise intensity, Butyricicoccus, Anaerostipes, Oxalobacter and Clostridium_IV in basketball players enrich. Further analysis of the functional prediction revealed that carbohydrate metabolism, amino acid metabolism, metabolism of xenobiotics and glycans and metabolism were significantly expressed in the gut microbiota of basketball athletes with high intensity. Conclusion: The study demonstrated that after long-term professional training, the gut microbiota of athletes adapts to exercise stimulators and can quickly respond to changes in exercise intensity. In high-intensity training, the organism is protected from harm by enriching some beneficial bacteria.

运用耦合协调发展模型相关研究成果,围绕城市化内涵,从土地、人口和社会三方面构建城市化评价指标体系;从生产资源、生产能力和生产保障三方面构建粮食安全评价指标体系,进而构建粮食安全与城市化耦合协调发展评价指标体系.本文以2009-2020年相关数据做支撑,定量评价云南粮食安全状态与城市化进程的耦合度与协调度,根据协调发展划分标准对该时段内粮食安全与城市化的协调发展类型进行划分,并在此基础上对二者的协调状态进行定量评价.研究表明:云南粮食安全与城市化协调发展先后经历了失调、磨合和协调三个阶段.自2017年起由城市化滞后向粮食安全滞后转变,城市化与粮食安全之间的相互依赖程度高,协调发展与总体发展趋势良好.城市化的发展有利于促进粮食安全水平提高,同时粮食安全水平的提高又可有效推进城市化进程.

Spiders are renowned for their efficient capture of flying insects using intricate aerial webs. How the spider nervous systems evolved to cope with this specialized hunting strategy and various environmental clues in an aerial space remains unknown. Here we report a brain-cell atlas of >30,000 single-cell transcriptomes from a web-building spider ( Hylyphantes graminicola ). Our analysis revealed the preservation of ancestral neuron types in spiders, including the potential coexistence of noradrenergic and octopaminergic neurons, and many peptidergic neuronal types that are lost in insects. By comparing the genome of two newly sequenced plesiomorphic burrowing spiders with three aerial web-building spiders, we found that the positively selected genes in the ancestral branch of web-building spiders were preferentially expressed (42%) in the brain, especially in the three mushroom body-like neuronal types. By gene enrichment analysis and RNAi experiments, these genes were suggested to be involved in the learning and memory pathway and may influence the spiders’ web-building and hunting behaviour. Our results provide key sources for understanding the evolution of behaviour in spiders and reveal how molecular evolution drives neuron innovation and the diversification of associated complex behaviours.

Marine-terrestrial transition represents an important aspect of organismal evolution that requires numerous morphological and genetic innovations and has been hypothesized to be caused by geological changes. We used talitrid crustaceans with marine-coastal-montane extant species at a global scale to investigate the marine origination and terrestrial adaptation. Using genomic data, we demonstrated that marine ancestors repeatedly colonized montane terrestrial habitats during the Oligocene to Miocene. Biological transitions were well correlated with plate collisions or volcanic island formation, and top-down cladogenesis was observed on the basis of a positive relationship between ancestral habitat elevation and divergence time for montane lineages. We detected convergent variations of convoluted gills and convergent evolution of SMC3 associated with montane transitions. Moreover, using CRISPR-Cas9 mutagenesis, we proposed that SMC3 potentially regulates the development of exites, such as talitrid gills. Our results provide a living model for understanding biological innovations and related genetic regulatory mechanisms associated with marine-terrestrial transitions.

Plutella xylostella granulovirus (PlxyGV) biopesticide is an effective tool to control the long-term damage of Plutella xylostella (Linnaeus) to cruciferous vegetables. In China, PlxyGV can be produced on a large scale using host insects, and its products have been registered in 2008. In experiments and biopesticide production, the routine enumeration method of PlxyGV virus particles is to use the Petroff-Hausser counting chamber in dark field microscope. However, the accuracy and repeatability of granulovirus (GV) counting are affected due to the small particle size of GV occlusion bodies (OBs), the limitations of optical microscope, the judgment of different operators, host impurities, the addition of biological products. This limits the convenience of its production, product quality, trading and field application. Here we use PlxyGV as an example, the method based on Real-time fluorescence quantitative PCR (qPCR) was optimized from two aspects of sample treatment and specific primers design, which improved the repeatability and accuracy of absolute quantitative OBs of GV. This study provides basic information for accurate quantitative PlxyGV by qPCR method.

Drought stress is one of the most sever natural disaster, threatening to plant growth and global crop security. Dendrobium officinale is a drought-tolerance crop with effective defense mechanisms against drought stress, as well as an important economic plant for medicinal, cosmetic, or ornamental purposes. Revealing the regulatory mechanisms conferring drought resistance upon D. officinale is thus crucial for genetic breeding and water-saving agriculture. In this study, the biochemical and transcriptomic profiles of two D. officinale genotypes were comprehensively analyzed under three drought stress conditions. The M genotype has a relative weaker drought tolerance, as shown by withered leaves, rapidly accumulated malondialdehyde, and severely repressed expression of photosynthesis-related genes under water deficit. In the O genotype (drought-tolerant genotype), proline content, ascorbate peroxidase and catalase activities significantly increased with intensifying drought stress, showing a higher level than that in the M genotype, especially under severe drought stress. By contrast, superoxide dismutase and peroxidase activities were higher in the M genotype under moderate and severe water deficient. Transcriptome analysis demonstrated that mild water deficit initiated the plant hormone signal transduction pathway, while severe drought stress launched the flavonoid biosynthesis pathway in both D. officinale genotypes. Notably, high expression of most protein phosphatases type 2 C in the M genotype, a negative regulator of abscisic acid signaling, may partially explain the relative weaker drought tolerance of the M genotype. Moreover, the higher flavonoid content corresponding with the highly expressed PAL and DFR in the O genotype than in the M genotype, may confer a stronger drought tolerance upon the O genotype under water deficit. Additionally, the biased expression pattern of heat shock proteins, late embryogenesis abundant proteins, and dehydrins may also be linked to the different drought responses of the two D. officinale genotypes. Our results provide a theoretical basis for drought-tolerant crops breeding and water-sparing agriculture.

Background Biologists have long debated the drivers of the genome size evolution and variation ever since Darwin. Assumptions for the adaptive or maladaptive consequences of the associations between genome sizes and environmental factors have been proposed, but the significance of these hypotheses remains controversial. Eragrostis is a large genus in the grass family and is often used as crop or forage during the dry seasons. The wide range and complex ploidy levels make Eragrostis an excellent model for investigating how the genome size variation and evolution is associated with environmental factors and how these changes can ben interpreted. Methods We reconstructed the Eragrostis phylogeny and estimated genome sizes through flow cytometric analyses. Phylogenetic comparative analyses were performed to explore how genome size variation and evolution is related to their climatic niches and geographical ranges. The genome size evolution and environmental factors were examined using different models to study the phylogenetic signal, mode and tempo throughout evolutionary history. Results Our results support the monophyly of Eragrostis. The genome sizes in Eragrostis ranged from ~0.66 pg to ~3.80 pg. We found that a moderate phylogenetic conservatism existed in terms of the genome sizes but was absent from environmental factors. In addition, phylogeny-based associations revealed close correlations between genome sizes and precipitation-related variables, indicating that the genome size variation mainly caused by polyploidization may have evolved as an adaptation to various environments in the genus Eragrostis. Conclusion This is the first study to take a global perspective on the genome size variation and evolution in the genus Eragrostis. Our results suggest that the adaptation and conservatism are manifested in the genome size variation, allowing the arid species of Eragrostis to spread the xeric area throughout the world.

大理茶(Camellia taliensis)是古茶林森林茶园的重要茶种之一,参与了大叶茶的起源驯化.为了解大理茶叶绿体基因组密码子偏好性,探讨影响密码子偏好性形成的因素,对其进行了中性绘图分析、ENC-plot、PR2-plot 分析,并寻找最优密码子.结果表明,大理茶叶绿体 54 条编码序列(CDS)的 GC 含量为 37.68％,GC1、GC2 的含量分别为 46.44％、39.77％,高于 GC3(27.67％),说明其叶绿体基因组密码子末位碱基偏好以 A、U 结尾;有效密码子数 ENC 范围为 35.64～56.67,平均值为 46.1,表明其密码子偏好性较弱;中性绘图分析、ENC-plot 分析和 PR2-plot 偏倚分析表明,影响大理茶叶绿体密码子偏好性的主要因素是自然选择;有 11 个密码子被确定为最优密码子.虽然基于matK基因和CDS序列构建的茶组植物系统发育树显示的拓扑结构有所不同,但所有树型均显示大理茶与秃房茶聚为一支,且是栽培茶的近缘种.本研究为解析大理茶的遗传进化,系统发育提供了基础,为大理茶重要农艺性状改良提供了科学依据.

Shallow-buried urban road tunnels with shafts (URTS) have been operated in large cities of China, and successfully released the traffic congestion. Fire smoke is expected to exhaust out of one-side shaft groups driven by its own thermal buoyancy. However, full-scale test data of the fire smoke spreading in such tunnel are still lacked, and the prediction models needs to be verified. In hot summer of year 2020, three full-scale experiments were carried out on two URTS. A 1.6 m (length) x 1.6 m (width) iron pan was placed on ground with diesel oil used as the fire source. Testing systems were arranged under the ceiling, on top openings of shafts and at bottoms of shafts. Lots of smoke were rapidly exhausted out of the shafts closer to the fire sources, but backflow occurred at bottoms of those shafts farther from the fire sources being not conducive to smoke extraction. Other three results of full-scale fire experiments conducted on one URTS in cold winter are provided here for comparison. The findings are that both the ceiling smoke temperatures and the smoke spreading velocities decayed longitudinally well with the exponential function, and the downstream temperature attenuation coefficient k2 were in range of 0.042 -0.188 being smaller than that of the upstream, also the hotter the weather, the smaller the k2; maximum values on top openings of the shafts were measured to be 47 degrees C in temperature, 5 m/s in velocity and 180 ppm in CO concentration; mass flow rates of the unit shafts were measured to decrease away from the fire sources that were 0.30 -1.77 kg/(s.m2) in Fires 1 and 2, and 0.46 -1.27 kg/(s.m2) in Fire 3, also the prediction models were confirmed not to be accurate enough; number Ri ' differed among all unit shafts of Shaft 6#, and were about 13.5 -15.2 in Fire 1, but smaller to be about 1.4 in Fire 2.