Search

Xenorhabdus, known for its symbiotic relationship with Entomopathogenic nematodes (EPNs), belongs to the Enterobacteriaceae family. This dual-host symbiotic nematode exhibits pathogenic traits, rendering it a promising biocontrol agent against insects. Our prior investigations revealed that Xenorhabdus stockiae HN_xs01, isolated in our laboratory, demonstrates exceptional potential in halting bacterial growth and displaying anti-tumor activity. Subsequently, we separated and purified the supernatant of the HN_xs01 strain and obtained a new compound with significant inhibitory activity on tumor cells, which we named XNAE. Through LC-MS analysis, the mass-to-nucleus ratio of XNAE was determined to be 254.24. Our findings indicated that XNAE exerts a time- and dose-dependent inhibition on B16 and HeLa cells. After 24 h, its IC50 for B16 and HeLa cells was 30.178 µg/mL and 33.015 µg/mL, respectively. Electron microscopy revealed conspicuous damage to subcellular structures, notably mitochondria and the cytoskeleton, resulting in a notable reduction in cell numbers among treated tumor cells. Interestingly, while XNAE exerted a more pronounced inhibitory effect on B16 cells compared to HeLa cells, it showed no discernible impact on HUVEC cells. Treatment of B16 cells with XNAE induced early apoptosis and led to cell cycle arrest in the G2 phase, as evidenced by flow cytometry analysis. The impressive capability of X. stockiae HN_xs01 in synthesizing bioactive secondary metabolites promises to significantly expand the reservoir of natural products. Further exploration to identify the bioactivity of these compounds holds the potential to shed light on their roles in bacteria-host interaction. Overall, these outcomes underscore the promising potential of XNAE as a bioactive compound for tumor treatment. [ABSTRACT FROM AUTHOR]

Aeromonas salmonicida is an important pathogen that causes furunculosis in trout and salmon with high morbidity and mortality, resulting in significant economic losses in aquaculture. Overuse of antibiotics has led to the continuous emergence of drug-resistant strains. Hence, there is an urgent need to find an alternative environmentally friendly antimicrobial agent. In this study, we isolated a virulent phage of A. salmonicida, named ASG01, which belongs to the Myoviridae family and maintains lytic activity at a pH value range from 4 to 12 and in the temperature range from 30 °C to 60 °C. The whole genomic sequence of ASG01 showed 82% similarity to Aeromonas phage pAh6-C. The cell wall hydrolase (Cwh)-encoding gene from the genome of ASG01 was predicted and heterologously expressed. Notably, in the absence of additional phage genes, endogenous expression of Cwh could lyse E. coli cells and greatly inhibit the growth of tested fish pathogenic bacteria. The lytic activity of Cwh was eliminated when the predicted active site was mutated. These results indicate that Cwh of ASG01 possessed excellent lytic activity and a wide antibacterial spectrum, suggesting its potential as an effective enzybiotic. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) production is necessary for global food and nutrition security. Reducing plant height is an effective strategy to increase lodging resistance, harvest index, and eventually wheat yield. Rht8 is a gibberellic acid–sensitive reduced height (Rht) gene and has been cloned. Rht8 encodes a ribonuclease H‐like (RNHL) superfamily protein that reduces plant height without reduction in coleoptile length. High‐throughput diagnostic markers are not available for precise selection of RNHL in wheat breeding. In this study, we found that different cultivars may carry 1–3 copies of RNHLs on chromosome 2D, and only 2D carries the semi‐dwarf allele of RNHL although the wild‐type RNHL allele is detected in several other chromosomes. We developed two kompetitive allele specific PCR (KASP) markers, Rht8‐KASP‐V2 and Rht8‐KASP‐V3, based on the causal variation in RNHL. The two markers co‐segregated with plant height in a recombinant inbred population and were validated in a panel of hard winter wheat breeding lines from the 2022 Regional Germplasm Observation Nursery and Regional Performance Nursery. Rht8 has not been extensively deployed in US hard winter wheat and development of the diagnostic KASP markers will facilitate Rht8 transfer to US wheat cultivars. Core Ideas: Each cultivar carries 1–3 copies of ribonuclease H‐like domains (RNHLs) on 2D and mutations in all those copies determine Rht8 phenotype.Two kompetitive allele‐specific PCR (KASP) markers were developed for the recently cloned Rht8 gene.The two markers were diagnostic for Rht8 in a wheat diversity panel.Low Rht8 frequency in US wheat suggests high potential of using Rht8 in the United States to improve US wheat production. [ABSTRACT FROM AUTHOR]

Type synthesis of parallel mechanism is regarded as the theoretical basis and source for the original innovation design of mechanical devices and robots. A new method for type synthesis of the fully-decoupled two-rotational and one-translational (2R1T) parallel mechanisms with three degrees of freedom is proposed in this paper. Based on the actuation wrench screw theory, the mathematical model mapping the input and output velocity vector space of the fully-decoupled 2R1T parallel mechanism is established. The actuation wrench screws and the actuated twist screws of the corresponding branches are derived according to the mathematic model. The forms of the unactuated screws are determined in terms of the reciprocal product theory. Structural synthesis of the branch chains is realized. Then type synthesis of parallel mechanisms is completed as well and lots of novel mechanisms are obtained. Finally, a 2RUPU-PU parallel mechanism synthesized is taken as an example to analyze its mobility and kinematics. Results show that the mechanism has two-rotational and one-translational degrees of freedom and its Jacobian matrix is a diagonal matrix, i.e., it has the fully-decoupled kinematic characteristics. Therefore, the method proposed is correct and effective to synthesize the fully-decoupled 2R1T parallel mechanisms. [ABSTRACT FROM AUTHOR]

The single‐molecule electronic devices offer the ultimate solution to miniaturize integrated circuits, and subthreshold swing (SS) is the key indicator of the power consumption for single‐molecule transistors but is still quite restricted. In this study, the redox‐mediated single‐molecule transistor with a SS down to 120 mV decade−1 in the faradaic potential region via the electrochemical‐STM break junction (EC‐STM‐BJ) technique is fabricated. With an off‐state leakage current of less than 10 pA and an on/off ratio of 100, the balance between low static power consumption and a high switching ratio is achieved. The theoretical investigations reveal that the conductance tuning is from the difference of transmission in the redox process. The study provides a new strategy for the design of single‐molecule transistors with promising SS, which is essential for the potential application of single‐molecule devices. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) wild relatives are rich genetic resources for genetic improvement of wheat. The short arm of rye (Secale cereale L.) chromosome 1 (1RS) contains many beneficial genes for resistance to drought, insects, and diseases, therefore the 1RS wheat translocations have been widely used in wheat breeding programs worldwide. To facilitate marker‐assisted identification of 1RS in wheat breeding, we designed a set of Kompetitive allele‐specific polymerase chain reaction (KASP) markers to detect the translocations of 1RS with long arm from wheat chromosome 1A (1RS.1AL) and 1RS with long arm from wheat chromosome 1B (1RS.1BL) based on the sequence flanking single nucleotide polymorphisms (SNPs) generated by genotyping‐by‐sequencing (GBS) between wheat and rye panels. We identified a set of three SNP markers for diagnosis and differentiation of the two 1RS translocations in wheat. Among the three KASP markers, 1AS‐05056 is 1RS specific, and clearly separated the genotypes with 1RS (1RS.1AL and 1RS.1BL) from those without the two 1RS translocations; whereas 1AS‐29875 clearly identified the 1RS.1AL translocation and 1BS‐16654 separated 1RS.1BL from 1RS.1AL. The three new KASP markers together accurately identified the presence of 1RS translocation on either 1A or 1B chromosome in a panel of 95 representative U.S. winter wheat accessions, which were further validated in two additional U.S. hard winter wheat panels. Therefore, they can be used for routine screening of 1RS.1BL and 1RS.1AL translocation lines in wheat breeding programs. Core Ideas: 1RS, 1AS, and 1BS specific SNPs were identified by analyzing GBS‐SNPs from both wheat and rye panels.Three chromosome‐arm‐specific KASPs clearly detected the 1RS.1AL and 1RS.1BL translocations in wheat.Three KASP markers were diagnostic for 1RS.1AL and 1RS.1BL in two U.S. hard winter wheat panels. [ABSTRACT FROM AUTHOR]

Xenorhabdus can produce a large number of secondary metabolites with insecticidal, bacteriostatic, and antitumor activities. Efficient gene editing tools will undoubtedly facilitate the functional genomics research and bioprospecting in Xenorhabdus. In this study, BlastP analysis using the amino acid sequences of Redαβ or RecET recombinases as queries resulted in the identification of an operon (XBJ1_operon 0213) containing RecET-like recombinases encoding genes from the genome of Xenorhabdus bovienii strain SS-2004. Three proteins encoded by this operon was indispensable for full activity of recombineering, namely XBJ1-1173 (RecE-like protein), XBJ1-1172 (RecT-like protein), and XBJ1-1171 (single-strand annealing protein). Using this newly developed recombineering system, a gene cluster responsible for biosynthesis of a novel secondary metabolite (Min16) was identified from X. stockiae HN_xs01 strain. Min16 which exhibited antibacterial and cytotoxic activities was determined to be a cyclopeptide composed of Acyl-Phe-Thr-Phe-Pro-Pro-Leu-Val by using high-resolution mass spectrometry and nuclear magnetic resonance analysis, and was designated as changshamycin. This host-specific recombineering system was proven to be effective for gene editing in Xenorhabdus, allowing for efficient discovery of novel natural products with attractive bioactivities. Key points: • Screening and identification of efficient gene editing tools from Xenorhabdus • Optimization of the Xenorhabdus electroporation parameters • Discovery of a novel cyclopeptide compound with multiple biological activities [ABSTRACT FROM AUTHOR]

Using glucosamine hydrochloride as the starting material, 4‐(methoxycarbonyl)‐5‐methyl‐1‐propyl‐1H‐pyrrole‐2‐carboxylic acid (3) was initially created as an intermediate compound by cyclization and oxidation in order to create novel high temperature stable pyrrole compounds. Furthermore, Steglich esterification was used to produce N‐substituted pyrrole esters (4 a–4 t). All the new compounds were verified using nuclear magnetic resonance (1H and 13CNMR), infrared spectroscopy (IR), and high resolution mass spectrometry (HRMS). Thermogravimetry (TG), differential scanning calorimetry (DSC), and pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS) techniques were used to examine the thermal behaviors of the compounds 4 f, 4 g, 4 i, and 4 q. Ester bonds from the pyrolysis products 4 g, 4 i, and 4 q might be severed which were consisted of the raw materials as well as the substrates, such as menthol, phenethyl and pyrrole derivatives which are commonly utilized in the sector of spices in foods and cigarette. [ABSTRACT FROM AUTHOR]

Saccharina latissima (sugar kelp) is one of the most widely cultivated brown marine macroalgae species in the North Atlantic and the eastern North Pacific Oceans. To meet the expanding demands of the sugar kelp mariculture industry, selecting and breeding sugar kelp that is best suited to offshore farm environments is becoming necessary. To that end, a multi-year, multi-institutional breeding program was established by the U.S. Department of Energy's (DOE) Advanced Research Projects Agency-Energy (ARPA-E) Macroalgae Research Inspiring Novel Energy Resources (MARINER) program. Hybrid sporophytes were generated using 203 unique gametophyte cultures derived from wild-collected Saccharina spp. for two seasons of farm trials (2019–2020 and 2020–2021). The wild sporophytes were collected from 10 different locations within the Gulf of Maine (USA) region, including both sugar kelp (Saccharina latissima) and the skinny kelp species (Saccharina angustissima). We harvested 232 common farm plots during these two seasons with available data. We found that farmed kelp plots with skinny kelp as parents had an average increased yield over the mean (wet weight 2.48 ± 0.90 kg m−1 and dry weight 0.32 ± 0.10 kg m−1) in both growing seasons. We also found that blade length positively correlated with biomass in skinny kelp x sugar kelp crosses or pure sugar kelp crosses. The skinny x sugar progenies had significantly longer and narrower blades than the pure sugar kelp progenies in both seasons. Overall, these findings suggest that sugar x skinny kelp crosses provide improved yield compared to pure sugar kelp crosses. [ABSTRACT FROM AUTHOR]

In order to use single top flavors with roasted sweet aroma in heated tobacco products for flavor enhancement, puff-by-puff release of six roasted sweet aroma compounds in the aerosols of heated tobacco products was measured using GC-MS. The six aroma components were added into the tobacco rod at 0.01% and 0.05% of tobacco mass, and the puff-by-puff transfer rates were determined. The results showed that: 1) The puff-by-puff releases of the six aroma components in the aerosol of heated tobacco products increased first and then decreased with the puff number. 2) When added at 0.01% and 0.05%, their puff-by-puff transfer rates were between 0.5%-15.6% and 1.0%-9.6%, respectively, and the per puff transfer rate peaked in the third or fourth puff. 3) There was a good linear positive correlation between the total of puff-by-puff transfer rates of the six single flavors in aerosols and the puff number. 4) At the two addition rates, the total transfer rates of the six single flavors in aerosols were between 34.2%-73.1% and 23.3%-63.7% respectively. [ABSTRACT FROM AUTHOR]

Our team has initiated a selective breeding program for regional strains of sugar kelp, Saccharina latissima, to improve the competitiveness of kelp farming in the United States. Within our breeding program, we also include an endemic putative species, Saccharina angustissima, locally referred to as skinny kelp. We crossed uniclonal gametophyte cultures derived from 37 wild‐collected blades representing five sugar kelp strains and one skinny kelp strain to produce 104 unique crosses. Each cross was outplanted on a near‐shore research farm located in the Gulf of Maine (GOM). After the first farming season, our results indicated that sugar kelp and skinny kelp were interfertile, and produced mature and reproductively viable sporophytes. Morphological traits of individual blades varied depending on the parental contribution (sugar vs. skinny), with significant differences found in progeny blade length, width, thickness, and in stipe length and diameter. Despite these differences, wet weight and blade density per plot showed no statistical differences regardless of the cross. Given their published genetic similarity and their interfertility shown here, S. angustissima and S. latissima may not be different species, and may each contribute genetic diversity to breeding programs aimed at meeting ocean farming and market needs. [ABSTRACT FROM AUTHOR]

The interconnection of all things and industrial integration is the current trend of the times. Among them, the interconnection of all things is the demand of informationization of the times, and the industrial integration is the demand of industrial development. The interconnection of all things is realized based on wireless communication technology. It is necessary to combine the development of the tourist area and the surrounding culture. The relationship between tourist attractions and culture needs to be fully and effectively developed. In order to fully explore the advantages of the cooperation between the two, it is necessary to combine modern technology to package the tour process of each characteristic culture of the scenic spot. Virtual reality is a modern technology that can combine culture and tourism. Wireless communication and VR technology are applied to the development of integration of culture and tourism. The process of tourism will promote profound changes in the tourism model. Under the demand for informatization in various industries, the tourism industry is gradually developing in this direction. The integration of culture and tourism will also be driven by informatization and technology. This paper analyzes the current situation of culture and tourism, summarizes the problems existing in the current process of integration of culture and tourism, and finally puts forward targeted solutions. Mainly in the process of the integration and development of tourism and cultural industries, the traditional culture and scenic spots are the basic factors, combined with wireless communication and virtual reality technology, to develop a tourism industry with technological characteristics of the new era. [ABSTRACT FROM AUTHOR]

Urban social civilization and the quality of life of residents are gradually improved, and the development scale and trend of the leisure tourism industry have been growing. This paper constructs a multi-source data fusion model based on an ensemble learning algorithm, uses Ctrip 2020 open data set to train the model, and then obtains the tourism information data processing and prediction results. This paper takes the data of Ctrip as the training set and compares the trained model with the data of tunic and Feizhu. In this paper, sensor detection technology is used to analyze many famous scenic spots in China, including tourist type, gender, and location. The results show that tourism feature extraction results are consistent with data from trending flying bamboo, tunics, and other websites, according to the results of a multi-source fusion of tourism information. Among them, in the data of the first half of 2020, the prediction accuracy of the model after data processing is about 62%. Affected by the epidemic situation, the accuracy of the model is low. In the second half of the year, the prediction accuracy is 78%, which can be used to fuse tourism information in a short time. Therefore, the data show that the model has high learning ability and high trend prediction ability in tourism data processing, which can provide necessary information support for tourists. [ABSTRACT FROM AUTHOR]

The overall objective of this study is to present an assessment of embryonic sporophyte development directly "seeded" on growing substrates using the proprietary binder AtSea and three formulations of calcium alginate. We conducted two independent experiments under controlled conditions in a laboratory setup. First, we compared the effect of salinity (0 ppt, 29 ppt, and 35 ppt) on the performance of the calcium alginate formulations. Second, we assessed the effect of direct seeding with binders on the development of sporophytes of four different size classes (i.e., 83.7, 183.1, 345.2, and 522.0 μm in length). Our results show that salinity affects the performance of calcium alginate with 0 ppt media allowing the formation of a thicker hydrogel than that formulated with 29 and 35 ppt. Results also show that AtSea retained more sporophytes than any formulations of calcium alginate. Although effective when cultures were maintained in complete stillness (i.e., no water motion), we detected 70–80% detachment when aeration was added. We also observed what appeared to be delayed sporophyte development compared with sporophytes growing as free floaters. [ABSTRACT FROM AUTHOR]

Key message: The recessive Hessian fly resistance gene h4 and flanking SNP markers were located to a 642 kb region in chromosome 1A of the wheat cultivar 'Java.' Hessian fly (HF), Mayetiola destructor, is one of the most destructive insect pests in wheat worldwide. The wheat cultivar 'Java' was reported to carry a recessive gene (h4) for HF resistance; however, its chromosome location has not been determined. To map the HF resistance gene in Java, two populations of recombinant inbred lines (RILs) were developed from 'Bobwhite' × Java and 'Overley' × Java, respectively, and were phenotyped for responses to infestation of HF Great Plains biotype. Analysis of phenotypic data from the F1 and the RIL populations confirmed that one recessive gene conditioned HF resistance in Java. Two linkage maps were constructed using single-nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS). The h4 gene was mapped to the distal end of the short arm of chromosome 1A, which explained 60.4 to 70.5% of the phenotypic variation for HF resistance in the two populations. The GBS-SNPs in the h4 candidate interval were converted into Kompetitive Allele-Specific Polymerase Chain Reaction (KASP) markers to eliminate the missing data points in GBS-SNPs. Using the revised maps with KASP markers, h4 was further located to a 642 kb interval (6,635,984–7,277,935 bp). The two flanking KASP markers, KASP3299 and KASP1871, as well as four other closely linked KASP markers, may be useful for pyramiding h4 with other HF resistance genes in breeding. [ABSTRACT FROM AUTHOR]

Hessian fly (HF, Mayetiola destructor Say), is a destructive insect pest in most wheat (Triticum aestivum L.) growing areas worldwide. Growing resistant cultivars can effectively reduce HF damage. The wheat cultivar 'Seneca' was reported to carry resistance genes H7 on chromosome 5D and H8 with unknown location. To further validate the resistance gene locations in Seneca, a recombinant inbred line (RIL) population from Bobwhite × Seneca was genotyped using 3,330 single nucleotide polymorphism (SNP) markers generated from genotyping‐by‐sequencing (GBS) and phenotyped for HF resistance in the greenhouse experiments. Phenotypic analyses showed at least two genes conditioning HF resistance in Seneca, but none of them was mapped on chromosome 5D, as previously reported. Instead, one major gene, designated as H7, was mapped to chromosome 6A and explained 60.7–78.3% of the phenotypic variation. The other gene with a minor effect, designated as H8, was found on chromosome 2B and explained 3.2–4.7% of the phenotypic variation. Based on the physical locations of flanking markers for H7 in the Chinese Spring reference genome, H7 was physically located in a 6‐Mb interval on 6AL. This study reassigned the major gene H7 to chromosome 6A and the minor gene H8 to 2B in Seneca using a high‐density SNP map. Seventeen GBS SNPs mapped in the H7 region were converted into Kompetitive allele specific polymerase chain reaction (KASP) markers for selecting this gene in breeding. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of cigarette paper properties on the combustion coal fallout propensity of burning slim cigarette, cigarette paper with different parameters ( grammage, air permeability, hemp pulp content, ash content, burn promoter content and proportion of potassium salts in burn promoter) was selected and the samples of fine cigarette were made. The parameters were set optimization. The results showed that the combustion coal fallout propensity of slim cigarettes decreased rapidly with the increase of paper grammage. The presence of air permeability, hemp pulp content and ash content in cigarette papers was able to promote the fallout propensity of combustion coal, in a content-dependent manner. Meanwhile, air permeability of cigarette paper exhibited a positive correlation to the combustion coal fallout propensity. The change of burn promoter content had no significant effect on reducing the tendency of the fallout propensity of combustion coal, while the excessively high proportion of potassium salts in burn promoter would cause the tendency of the fallout propensity of combustion coal to fall rapidly. The four parameters of air permeability, grammage, burn promoter content and proportion of potassium salts in burn promoter were sorted in descending order of the influence on the combustion coal fallout propensity as below: air permeability > grammage > proportion of potassium salts in burn promoter > burn promoter content. The combustion coal fallout propensity decreased from6. 3% to 2.5% with the optimum cigarette paper parameters of air permeability 50 CU, grammage 34 ⋅ m-2, proportion of potassium salts in burn promoter 50%, burn promoter content 1.5%. [ABSTRACT FROM AUTHOR]

Silicon (Si) has been shown to increase plant stress tolerance. However, the molecular mechanisms underlying the effects of Si in alleviating drought stress in winter wheat are unknown. The aim of this study was to investigate the effects of Si on photosynthetic pigments, antioxidant contents, and transcription of several genes involved in the antioxidant defense pathway in drought-stressed wheat plants. Si application resulted in higher leaf chlorophyll content, and lower lipid peroxidation levels and HO contents in wheat flag leaves compared with untreated plants. In addition, Si increased the contents of ascorbate (ASC), reduced glutathione (GSH), and the total phenolic and total flavonoid contents in wheat flag leaves. Quantitative real-time PCR was used to analyze gene expression patterns for three antioxidant enzyme genes, four ASC-GSH cycle genes, and five flavonoid biosynthesis pathway genes. Si application increased the expression of these genes in drought-stressed wheat compared with the −Si treatments. Elevated levels of gene expression and low malondialdehyde and HO contents indicate that Si plays a pivotal role in the coordinated transcriptional regulation of multiple antioxidant defenses in response to drought. Our work also suggests that Si may be important in the metabolic or physiological activities for growth and development of winter wheat. [ABSTRACT FROM AUTHOR]

BACKGROUND Understanding the variance of antioxidant in wheat grain responses to irrigation and nitrogen (N) fertiliser management will improve the nutrient quality of wheat grain. Four N rates (0, 180, 240, and 300 kg ha−1) combined with irrigation times (I0, no irrigation; I1, jointing time irrigation; I2, jointing + flowering time irrigation), were used to determine the effect of N fertilisation and irrigation on total phenolic content (TPC), phenolic acid composition, and antioxidant activity (AOA) of wheat grain. RESULTS Irrigation, N fertilisation and their interactions had significant effect on TPC, total flavonoid content (TFC), AOA, p-coumaric acid (PCA), as well as vanillic acid (VA) and chlorogenic acid (CA). I1N300 treatment had the highest TPC at Zhengzhou and Wenxian (1451.5 µg g−1 and 1397.9 µg g−1, respectively) location, while I1N240 resulted in the highest TFC (0.75 mg g−1) and VA (19.77 µg g−1) at Wenxian. TPC, TFC, AOA, ferulic acid (FA), PCA and VA increased with N application rate (from 180 to 300 kg N ha−1). CONCLUSION An appropriate irrigation and N management improved antioxidant content and AOA in wheat grain. Generally, I1N240 and I1N300 treatment resulted in the higher TPC, TFC, AOA, as well as phenolic acid, i.e. FA and VA. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A Correction to this paper has been published: https://doi.org/10.1007/s10811-020-02345-4 [ABSTRACT FROM AUTHOR]