Rhizosphere microorganisms play an important role in the interactions of many species in the rhizosphere, including soil nematodes. One hundred strains of rhizosphere actinomycetes were screened in ...vitro for their effects on the chemotactic behavior of the root-knot nematode, Meloidogyne incognita. Volatile compounds produced by the strain Streptomyces plicatus G demonstrated both strong attractant and repellent activities towards M. incognita. The compound dibenzofuran attracted M. incognita nematodes strongly, while compound benzothiazole repelled them. The chemotaxis of M. incognita was also tested under controlled conditions in pot experiments. Cultures of S. plicatus G and volatile dibenzofuran attracted M. incognita while volatile benzothiazole repelled them. The results showed that volatile compounds produced by rhizosphere actinomycetes could influence the chemotaxis of nematodes to a host. This study provides new information about the interrelationship between rhizosphere actinomycetes and nematodes that may be useful in preventing nematode parasitism of agricultural crops.
In the wake of the restrictions imposed on social interactions due to the COVID-19 pandemic, traditional classroom education was replaced by distance education in many universities. Under the changed ...circumstances, students are required to learn more independently. The challenge for teachers has been to duly ascertain students’ learning efficiency and engagement during online lectures. This paper proposes an optimized lightweight convolutional neural network (CNN) model for engagement recognition within a distance-learning setup through facial expressions. The ShuffleNet v2 architecture was selected, as this model can easily adapt to mobile platforms and deliver outstanding performance compared to other lightweight models. The proposed model was trained, tested, evaluated and compared with other CNN models. The results of our experiment showed that an optimized model based on the ShuffleNet v2 architecture with a change of activation function and the introduction of an attention mechanism provides the best performance concerning engagement recognition. Further, our proposed model outperforms many existing works in engagement recognition on the same database. Finally, this model is suitable for student engagement recognition for distance learning on mobile platforms.
•OS-β-CD was prepared by esterifying β-CD with OSA.•The structures of OS-β-CD were characterized.•The emulsions stabilized by β-CD and OS-β-CD were evaluated.
The aim of this study was to synthesize ...and characterize the octenyl succinic-β-cyclodextrin (OS-β-CD) and assess its application as a potential emulsion stabilizer. OS-β-CD was prepared by esterifying β-CD with OSA under alkaline conditions. The properties of OS-β-CD were characterized by Fourier transform infrared, 13C and 1H NMR spectroscopy, X-ray diffraction (XRD), which demonstrated that OS groups had been introduced into the β-CD molecules and most of OS substitution occurred at the C-6 hydroxyl group of glycosyl units. The properties of emulsions stabilized by β-CD and OS-β-CD were evaluated via surface and interface tensiometry, determination of the creaming index and droplet size. The results showed that emulsions stabilized by β-CD broke just after 24h storage at 25°C. The emulsions prepared by OS-β-CD with all degree of substitution (DS) possessed a smaller oil droplet size and improved storage stability compared with that of the emulsion generated using β-CD.
In this study, the unbiased crystal structure analysis by particle swarm optimisation (CALYPSO) combined with the density functional theory (DFT) method were used to perform a structure search for ...neutral Cs
2
B
n
(n = 1-12) clusters, as well as the corresponding global minimum of the potential energy surface were determined. The ground-state structures of the Cs
2
B
n
(n = 1-12) clusters have four types of geometries: planar, arch bridge, double pyramid, and shield shape. Subsequently, the relative stability of the ground-state structures was systematically analysed based on three effective rules, which indicates that the C
7V
Cs
2
B
8
with a double pyramid structure has unusual stability. The results of the molecular orbitals (MOs) and density of states analysis (DOS) show that the B-2s and 2p atomic orbitals of Cs
2
B
8
are the main components of MOs. In addition, from the results of adaptive natural density partitioning (AdNDP) and localised orbital locator (LOL), it can be seen that the excellent stability of Cs
2
B
8
originates from the delocalised large π bonds with aromaticity and the s-p bonding of B-B. Our results reveal the structural growth mode of Cs
2
B
n
clusters and enrich the chemical bonding properties of boron-based clusters.
When conducting metagenomic analysis on gut microbiomes, there is no general consensus concerning the mode of sampling: non-contact (feces), noninvasive (rectal swabs), or cecal. This study aimed to ...determine the feasibility and comparative merits and disadvantages of using fecal samples or rectal swabs as a proxy for the cecal microbiome. Using broiler as a model, gut microbiomes were obtained from cecal, cloacal, and fecal samples and were characterized according to an analysis of the microbial community, function, and resistome. Cecal samples had higher microbial diversity than feces, while the cecum and cloaca exhibited higher levels of microbial community structure similarity compared with fecal samples. Cecal microbiota possessed higher levels of DNA replicative viability than feces, while fecal microbiota were correlated with increased metabolic activity. When feces were excreted, the abundance of antibiotic resistance genes like tet and ErmG decreased, but some antibiotic genes became more prevalent, such as fexA, tetL, and vatE. Interestingly, Lactobacillus was a dominant bacterial genus in feces that led to differences in microbial community structure, metabolism, and resistome. In conclusion, fecal microbiota have limited potential as a proxy in chicken gut microbial community studies. Thus, feces should be used with caution for characterizing gut microbiomes by metagenomic analysis.
Aims The responses of functional structures in plant communities to global change drivers is predicted to be driven by both species turnover and intraspecific trait variability (ITV). However, the ...relative importance of those two drivers is not well-known, which retards our ability to predict the functional changes of plant community under global change scenarios. We hypothesized that ITV rather than species turnover would drive the nutritional responses of plant community at the initial stage after nitrogen and water enrichment. Methods We measured community weighted means (CWM) and non-weighted means (CM) of foliar N and P concentrations and N:P ratio in a temperate steppe after two years factorial N and water addition. Species composition and nutrition traits of each species were recorded in each plot. Results The impacts of N addition on community level nutrition traits were highly dependent on water conditions, as indicated by significant interactive effects between N and water addition. Nitrogen addition significantly increased CWM of foliar N, but only under ambient water condition. Water addition decreased CWM of foliar P and increased that of N:P. Consistent with our hypothesis, communities responded to both N and water addition after two years treatments mainly through ITV. Conclusions Our results highlight the importance of ITV in driving short-term responses of community functional composition to the increases of nitrogen and water availability in the temperate steppe. The existence of interactive effects of N and water addition would make it more difficult to predict the impacts of N deposition on plant-mediated biogeochemical cycling under the scenarios of precipitation regime changes than previously assumed.
Treatment failure for esophageal carcinoma is frequently due to lymph node metastasis and invasion to neighboring organs. The aim of the present study was to investigate invasion- and ...metastasis-related genes in esophageal carcinoma cells in vitro and in vivo.
A metastasis model using a Matrigel invasion clonal selection approach was employed to establish a highly invasive subline EC9706-P4 from the esophageal carcinoma cell (ESCC) line EC9706. The differentially expressed genes of the subline and the parental cells determined by gene microarrays were further analyzed by RT-PCR and Western blotting.
We identified sphingosine kinase 1 (SPHK1) as an invasion and metastasis-related gene of esophageal cancer. SPHK1 was overexpressed in the EC9706-P4 subline with high invasive capacity. Among six ESCC lines tested, KYSE2 and KYSE30 cells showed the highest SPHK1 mRNA and protein expressions as well as the most invasive phenotype. By Western blotting, in 7/12 cases (58%), SPHK1 expression was higher in esophageal carcinomas than in the companion normal tissue. In 23/30 cases (76%), SPHK1 protein expression was upregulated in the tumors compared to matched normal tissue by immunohistochemistry (IHC). Esophageal carcinoma tissue microarray analysis indicated that SPHK1 expression correlated with the depth of tumor invasion (P < 0.0001) and lymph node metastasis (P = 0.016). By Kaplan-Meier analysis, strong SPHK1 expression was significantly associated with clinical failure (P < 0.01), suggesting the involvement of SPHK1 in aggressiveness of human esophageal carcinoma. SPHK1 overexpression significantly increased the invasiveness of EC9706 cells in vitro and also increased EC9706 cell growth and spontaneous metastasis in vivo, promoting significant increases in tumor growth, tumor burden and spontaneous lung metastasis in nude mice. SPHK1 expression significantly correlated with the expression of many EGFR pathway genes associated with invasion of cancer cells. SPHK1 protein expression also significantly correlated with the phosphorylation of EGFR.
In summary, our data implicate SPHK1 in the metastasis of esophageal cancer. Our study also identified downstream mediators of SPHK1 in esophageal cancer cells that may mediate enhanced malignant behavior, and several of these mediators may be useful as therapeutic targets.
Natural antisense transcripts (NATs) are commonly observed in eukaryotic genomes, but only a limited number of such genes have been identified as being involved in gene regulation in plants. In this ...research, we investigated the function of small RNA derived from a NAT in fiber cell development.
Using a map-based cloning strategy for the first time in tetraploid cotton, we cloned a naked seed mutant gene (N1
) encoding a MYBMIXTA-like transcription factor 3 (MML3)/GhMYB25-like in chromosome A12, GhMML3_A12, that is associated with fuzz fiber development.
The extremely low expression of GhMML3_A12 in N1 is associated with NAT production, driven by its 3′ antisense promoter, as indicated by the promoter-driven histochemical staining assay. In addition, small RNA deep sequencing analysis suggested that the bidirectional transcriptions of GhMML3_A12 form double-stranded RNAs and generate 21–22 nt small RNAs. Therefore, in a fiber-specific manner, small RNA derived from the GhMML3_A12 locus can mediate GhMML3_A12 mRNA self-cleavage and result in the production of naked seeds followed by lint fiber inhibition in N1 plants.
The present research reports the first observation of gene-mediated NATs and siRNA directly controlling fiber development in cotton.
Through the formation of the thermodynamically favored Cr(III)–O bond, the Nozaki–Hiyama–Kishi reaction has been widely applied in the functionalization of carbonyl compounds with the help of Ni ...catalysis. Herein, a divergent regio- and stereoselective diarylation of dienes has been developed under Ni/Cr cocatalysis without the inherent driving force for the formation of polar metal alkoxides. Preliminary experimental studies have been conducted to elucidate the key roles of Ni, Cr, and redox-active bis(imino)pyridine (PDI) ligands. The proposed mechanism suggests that the newly formed C–C bond of this diarylation was created by organonickel species instead of organochromium species.
Laser–plasma accelerators (LPAs) have been demonstrated as one of the candidates for traditional accelerators and have attracted increasing attention due to their compact size, high acceleration ...gradients, low cost, etc. However, LPAs for positrons still face many challenges, such as the beam divergence controlling, large energy spread, and complicated plasma backgrounds. Here, we propose a possible multistage positron acceleration scheme for high energy positron beam acceleration and propagation. It is driven by the strong coherent THz radiation generated when an injected electron ring beam passes through one or more solid targets. Multidimensional particle-in-cell simulations demonstrated that each acceleration stage is able to provide nearly 200 MeV energy gain for the positrons. Meanwhile, the positron beam energy spread can be controlled within 2%, and the beam emittance can be maintained during the beam acceleration and propagation. This may attract one’s interests in potential experiments on both large laser facilities and a traditional accelerator together with a laser system.
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