Simultaneous detection of multi-channel signals in MHz bandwidth using nitrogen-vacancy centers in a diamond.

In this paper, we propose a method for simultaneously recovering multiple radio wave signals based on nitrogen-vacancy (NV) centers in diamond combining optically detected magnetic resonance (ODMR) spectrum. A controlled magnetic field gradient applied to the laser excitation area on the surface of diamond widens the detectable ODMR bandwidth to 200 MHz. Three different frequency-modulated (FM) signals with distinct carrier frequencies falling within the resonance frequency range are received and demodulated in real-time. Subsequently, the FM signal reception capability of this system is further investigated by measuring baseband signal frequencies ranging from 0.1 Hz to 200 Hz and adjusting the carrier power within a dynamic range from -10 dBm to 30 dBm. This proposal, which accomplishes multi-channel demodulation using a compact and single device, has potential applications in fields such as wireless communication, radar and navigation.

Imaging electromagnetic boundary of microdevice using a wide field quantum microscope.

Imaging of electronic device surface or sub-surface electromagnetic fields under operating conditions is important for device design and diagnosis. In this study, we proposed a method to characterize specific magnetic field properties of electromagnetic devices at micron-scale using a solid-state quantum sensor, namely diamond nitrogen-vacancy (NV) centers. By employing a wide-field magnetic field measurement technique based on NV centers, we rapidly obtain the first-order magnetic field distribution of anomalous regions. Furthermore, we approximate the second-order magnetic field (magnetic gradient tensor) using the differential gradient method. To visualize the electromagnetic anomalous regions boundary, we utilize the tensor invariants of the magnetic gradient tensor components, along with their nonlinear combinations. The identification error rate of the anomalous regions is within 12.5%. Additionally, the electromagnetic field of anomalous regions is simulated showing the measurement accuracy. Our study shows that the experimental results are very similar to the theoretical simulation of the electromagnetic field (error: 7%). This work is essential for advancing electromagnetic field characterization of electronic devices and the advancement of quantum magnetic sensor applications.

Perceived control, self-management efficacy, and quality of life in patients treated with radiation therapy for breast cancer: a longitudinal study.

OBJECTIVE: This longitudinal study aims to examine the present state of perceived control, self-management efficacy, and overall quality of life (QoL) in patients with breast cancer undergoing radiotherapy, and gain insight into the dynamic trends and factors that influence the quality of life experienced by patients during the course of radiotherapy. METHODS: Participants completed the Cancer Experience and Efficacy Scale (CEES), Strategies Used by People to Promote Health (SUPPH), and Functional Assessment of Cancer Therapy- Breast (FACT-B). The data was analyzed using the software SPSS26.0. Repeated measures analysis of variance (ANOVA) and mixed-effects linear models were used to analyze trends in perceived control, self-management efficacy, and QoL at three-time points, as well as factors affecting QoL during radiotherapy. RESULTS: Perceived control and self-management efficacy were associated with QoL over the course of the radiotherapy. Self-management efficacy (ß = 0.30, P < 0.001), presence of chemotherapy (ß = 18.33, P = 0.024), and duration of illness (ß = 2.25, P = 0.028) had a positive effect on the change in QoL, while time (ß = - 2.95, P < 0.001), cancer experience (ß = - 0.46, P < 0.001), and type of medical insurance (ß = - 2.77, P = 0.021) had the negative effect on the change in QoL. CONCLUSION: The QoL, perceived control, and self-efficacy of patients with breast cancer show dynamic changes during radiotherapy. The higher the self-efficacy, the better the QoL, and the worse the QoL when the sense of disease control is poor. At the same time, more attention should be paid to the QoL of breast cancer radiotherapy patients with a long course of the disease, receiving chemotherapy, and different medical payment methods.

A novel deep learning-based algorithm combining histopathological features with tissue areas to predict colorectal cancer survival from whole-slide images.

BACKGROUND: Many methodologies for selecting histopathological images, such as sample image patches or segment histology from regions of interest (ROIs) or whole-slide images (WSIs), have been utilized to develop survival models. With gigapixel WSIs exhibiting diverse histological appearances, obtaining clinically prognostic and explainable features remains challenging. Therefore, we propose a novel deep learning-based algorithm combining tissue areas with histopathological features to predict cancer survival. METHODS: The Cancer Genome Atlas Colon Adenocarcinoma (TCGA-COAD) dataset was used in this investigation. A deep convolutional survival model (DeepConvSurv) extracted histopathological information from the image patches of nine different tissue types, including tumors, lymphocytes, stroma, and mucus. The tissue map of the WSIs was segmented using image processing techniques that involved localizing and quantifying the tissue region. Six survival models with the concordance index (C-index) were used as the evaluation metrics. RESULTS: We extracted 128 histopathological features from four histological types and five tissue area features from WSIs to predict colorectal cancer survival. Our method performed better in six distinct survival models than the Whole Slide Histopathological Images Survival Analysis framework (WSISA), which adaptively sampled patches using K-means from WSIs. The best performance using histopathological features was 0.679 using LASSO-Cox. Compared to histopathological features alone, tissue area features increased the C-index by 2.5%. Based on histopathological features and tissue area features, our approach achieved performance of 0.704 with RIDGE-Cox. CONCLUSIONS: A deep learning-based algorithm combining histopathological features with tissue area proved clinically relevant and effective for predicting cancer survival.

Effect of Preparation Processes on Structural Thermal Stability and Collision Energy Dissipation of Common Antirelaxation Coatings on Quartz Substrates.

Paraffin and octadecyltrichlorosilane (OTS) coatings can alleviate collisions between alkali-metal atoms and cell walls and then prolong the atomic spin-polarization lifetime. The surface structure and collision effects of these antirelaxation coatings, as well as the methods to avoid antirelaxation invalidity, have been the focus of researchers. This study investigated the thermolability of coating surface structure and the collision interactions between alkali metal atoms and coatings, considering the influence of various coating preparation factors, where this collision interaction is indirectly analyzed by measuring the collision energy dissipation between an atomic force microscopy (AFM) probe and the atoms on the coating surface. We found that appropriate evaporation time, carbochain length, and postannealing process can enhance the thermostability of the paraffin coating and eliminate its morphological defects. Furthermore, the OTS/water concentration, the soaking time, and the type of solvent have different levels of influence on the cluster formation and the thermostability of the OTS coatings. Moreover, the antirelaxation performance of coatings has been shown to be characterized by counting the energy dissipated when the AFM probe collides with the antirelaxation coating, replacing the conventional light-atom interaction- based method for measuring the relaxation characteristics, but requiring specific coating preparation factors to be maintained.

[Mechanism of Buyang Huanwu Decoction glycosides against atherosclerotic inflammation through NF-κB signaling pathway].

This study aims to explore the effect of Buyang Huanwu Decoction glycosides on the inflammatory response of apolipoprotein E~(-/-)(ApoE~(-/-)) mice and RAW264.7 cells through nuclear factor kappa-B(NF-κB) signaling pathway. In the in vivo experiment, ApoE~(-/-) mice were fed with high-fat diets for 12 weeks to induce the animal model of atherosclerosis, and 75 µg·mL~(-1) oxidized low-density lipoprotein(Ox-LDL) incubated RAW264.7 cells for 24 h to establish the atherosclerosis cell model. Automatic biochemical analyzer, hematoxylin-eosin(HE) staining, enzyme-linked immunosorbent assay(ELISA), Western blot, and droplet digital polymerase chain reaction(PCR) were used to determine the blood lipid levels, aortic intimal thickness, inflammatory factor content, NF-κB pathway-related proteins, and mRNA expression levels, and evaluate arterial atherosclerotic lesions and anti-atherosclerotic mechanisms of the drug. The model of atherosclerosis was successfully established in ApoE~(-/-) mice after 12 weeks of feeding with high-fat diets. In the model group, the plasma levels of total cholesterol(TC), triglyceride(TG), and low-density lipoprotein cholesterol(LDL-C) were increased(P<0.01), the intima of the blood vessels was thickened, the levels of inflammatory factors tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were increased, and the protein and mRNA expressions of NF-κB and inhibitor of NF-κB(IκBα) were significantly increased as compared with the control group. Compared with the model group, the high-dose Buyang Huanwu Decoction glycoside group decreased the plasma levels of TC, TG, and LDL-C, reduced the plaque area and thickness and the content of inflammatory factor TNF-α, and inhibited the protein and mRNA expressions of NF-κB and IκBα, with the effect same as Buyang Huanwu Decoction. In the in vivo experiment, 75 µg·mL~(-1) Ox-LDL stimulated RAW264.7 cells for 24 h to successfully establish a foam cell model. As compared with the control group, the nuclear amount of NF-κB and the protein and mRNA expressions of IκBα in the model group increased. Compared with the model group, the middle-dose and high-dose Buyang Huanwu Decoction glycoside groups decreased the nuclear amount of NF-κB and the protein and mRNA expressions of IκBα. The above results show that the glycosides are the main effective substances of Buyang Huanwu Decoction against atherosclerosis, which inhibit the NF-κB pathway and reduce the inflammatory response, thus playing the role against atherosclerotic inflammation same as Buyang Huanwu Decoction.

Survey on the Construction Status of Forensic Virtual Autopsy Laboratory and the Applicability of Laboratory Accreditation.

OBJECTIVES: To survey the development status and actual needs of virtual autopsy technology in China and to clarify the applicability of forensic virtual autopsy laboratory accreditation. METHODS: The questionnaire was set up included three aspects：(1) the current status of virtual autopsy technology development; (2) the accreditation elements such as personnel, equipment, entrustment and acceptance, methods, environmental facilities; (3) the needs and suggestions of practicing institutions. A total of 130 forensic pathology institutions were surveyed by online participation through the Questionnaire Star platform. RESULTS: Among the 130 institutions, 43.08% were familiar with the characteristics of virtual autopsy technology, 35.38% conducted or received training in virtual autopsy, and 70.77% have establishment needs (including maintenance). Relevant elements were suitable for laboratory accreditation. CONCLUSIONS: Virtual autopsy identification has gained social recognition. There is a demand for accreditation of forensic virtual autopsy laboratory. After the preliminary assessment, considering the characteristics and current situation of this technology, China National Accreditation Service for Conformity Assessment (CNAS) can first carry out the accreditation pilot of virtual autopsy project at large comprehensive forensic institutions with higher identification capability, and then CNAS can popularize the accreditation in a wide range when the conditions are suitable.

An edible molecularly imprinted material prepared by a new environmentally friendly deep eutectic solvent for removing oxalic acid from vegetables and human blood.

A novel deep eutectic solvent-magnetic molecularly imprinted polymer (DES-MMIP) for the specific removal of oxalic acid (OA) was prepared by an environmentally friendly deep eutectic solvent, consisting of betaine, citric acid, and glycerol, which acted as the functional monomer for polymerization. The structure and morphology of DES-MMIPs were studied by X-ray diffraction, scanning and transmission electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. DES-MMIPs had a core-shell structure, with magnetic iron oxide as the core, and showed good thermal stability and high adsorption capacity (18.73 mg/g) for OA. The adsorption process of OA by DES-MMIPs followed the pseudo-second-order kinetic model and Langmuir isotherm model. DES-MMIPs had significant selectivity for OA and their imprinting factor was 3.26. When applied to real samples, high performance liquid chromatography analysis showed that DES-MMIPs could remove OA from both spinach and blood serum. These findings provide potential methods for removal of OA from vegetables and for specific removal of OA in renal dialysis.

Screening of acetylcholinesterase inhibitory and antioxidant active compounds from Terminalia chebula fruits by spectrum-effect relationship and liquid chromatography-mass spectrometry analysis.

Screening and identification of active components from traditional Chinese medicines is rather challenging due to the diversity and complexity of chemical components. Herein, a comprehensive strategy based on a spectrum-effect relationship model and LC-MS analysis was developed to screen active components from Terminalia chebula fruits. The water extract of T. chebula fruits was subjected to macroporous resin column and then eluted successively with water and 30%, 50%, 70%, and 95% ethanol. The 30% ethanol eluate fractions of eighteen batches from T. chebula fruits were used for the spectrum-effect relationship study. The IC50 values for acetylcholinesterase inhibitory and 2,2-diphenyl-1-picrylhydrazyl scavenging activities were measured, LC fingerprints were established, and 15 common peaks were specified. The spectrum-effect relationship between common peaks and IC50 values was investigated by principal component analysis, gray relational analysis, partial least square and multiple linear regression. The 30% ethanol eluate fraction was further characterized by LC-MS analysis. The chromatographic peaks (Peaks 1, 2, 3, 5, 12, 14, 15) making great contributions to the efficacy were screened through a spectrum-effect relationship model, and sixteen components were further identified. The results suggested that the proposed strategy is simple and effective for acquiring active components from a complex matrix.

α-Glucosidase inhibitors screening from Cyclocarya paliurus based on spectrum-effect relationship and UPLC-MS/MS.

Cyclocarya paliurus is an edible and medicinal plant exhibiting significant hypoglycemic effect. However, its active components are still unclear and need further elucidation. In this research, the active components of the leaves of C. paliurus responsible for the α-glucosidase inhibitory activity were screened and identified based on a spectrum-effect relationship study in combination with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis. The 70% ethanol eluate fraction of the leaves of C. paliurus with the strongest α-glucosidase inhibitory activity was obtained after extraction and purification with macroporous resin. Their chromatographic fingerprints (15 batches) were established by UPLC analysis and 32 common peaks were specified by similarity analysis. Their IC50 values for α-glucosidase inhibition were measured by an enzymatic reaction. Several multivariate statistical analysis methods including hierarchical cluster analysis, principal component analysis, partial least square analysis and gray relational analysis were applied to explore the spectrum-effect relationship between common peaks and IC50 values, and the chromatographic peaks making a large contribution to efficacy were screened out. To further elucidate the active components of leaves of C. paliurus, the 70% ethanol eluate fraction was characterized by UPLC-MS/MS analysis, and 10 compounds were identified. This study provides a valuable reference for further research and development of hypoglycemic active components of C. paliurus.

The Cotton Lignin Biosynthetic Gene Gh4CL30 Regulates Lignification and Phenolic Content and Contributes to Verticillium Wilt Resistance.

Verticillium wilt is a vascular disease causing tremendous damage to cotton production worldwide. However, our knowledge of the mechanisms of cotton resistance or susceptibility to this disease is very limited. In this study, we compared the defense transcriptomes of cotton (Gossypium hirsutum) cultivars Shidalukang 1 (Verticillium dahliae resistant, HR) and Junmian 1 (V. dahliae susceptible, HS) before and after V. dahliae infection, identified hub genes of the network associated with responses to V. dahliae infection, and functionally characterized one of the hub genes involved in biosynthesis of lignin and phenolics. We identified 6,831 differentially expressed genes (DEGs) between the basal transcriptomes of HR and HS; 3,685 and 3,239 of these DEGs were induced in HR and HS, respectively, at different time points after V. dahliae infection. KEGG pathway analysis indicated that DEGs were enriched for genes involved in lignin biosynthesis. In all, 23 hub genes were identified based on a weighted gene coexpression network analysis of the 6,831 DEGs and their expression profiles at different time points after V. dahliae infection. Knockdown of Gh4CL30, one of the hub genes related to the lignin biosynthesis pathway, by virus-induced gene silencing, led to a decreased content of flavonoids, lignin, and S monomer but an increased content of G monomer, G/S lignin monomer, caffeic acid, and ferulic acid, and enhanced cotton resistance to V. dahliae. These results suggest that Gh4CL30 is a key gene modulating the outputs of different branches of the lignin biosynthesis pathway, and provide new insights into cotton resistance to V. dahliae.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Effects and mechanism of lncRNA-27785.1 that regulates TGF-ß1 of Sika deer on antler cell proliferation.

Transforming growth factor (TGF-ß) plays an important role in the development of deer antlers. The purpose of this study was to investigate the role of long noncoding RNA in the transcriptional regulation of TGF-ß1 and its relationship with the proliferation and differentiation of antler chondrocytes. High-throughput sequencing was used to screen lncRNAs related to TGF-ß1. Next, the overexpression plasmid and interference sequence of target lncRNA27785.1 were constructed and transfected into chondrocytes. We found that lncRNA27785.1 inhibited the proliferation and migration of chondrocytes and delayed the transition of cells from G1 to S phase. qRT-PCR and Western blot analysis indicated that the overexpression of lncRNA27785.1 may downregulate mRNA and protein expression of TGF-BR2, Smad3, pSmad3, and Smad4. Our findings highlight lncRNA27785.1 as an inhibitor of chondrocytes proliferation and differentiation by negatively regulating the TGF-ß/Smad signaling pathway; this implicates an important regulatory role for long noncoding RNA in the regeneration of antler.

Charge Behavior of Terminal Hydroxyl on Rutile TiO2(110).

Titanium dioxide (TiO2) is of considerable interest as a photocatalyst and a catalyst support. Surface hydroxyl groups (OH) are the most common adsorbates on the TiO2 surface and are believed to play crucial roles in their applications. Although the characteristics of bridging hydroxyl (OHbr) have been well understood, the adsorption structure and charged states of terminal hydroxyl (OHt) have not yet been experimentally elucidated at an atomic scale. In this study, we have investigated an isolated OHt on the rutile TiO2(110) surface by atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We found that OHt is in a negatively charged state. The unique characteristic of OHt is different from that of OHbr and involves the amphoterism and diversity of catalytic reactions of TiO2.

Size-dependent strain-engineered nanostructures in MoS2monolayer investigated by atomic force microscopy.

The strain has been employed for controlled modification of electronical and mechanical properties of two-dimensional (2D) materials. However, the thermal strain-engineered behaviors of the CVD-grown MoS2have not been systematically explored. Here, we investigated the strain-induced structure and properties of CVD-grown triangular MoS2flakes by several advanced atomic force microscopy. Two different kinds of flakes with sharp-corner or vein-like nanostructures are experimentally discovered due to the size-dependent strain behaviors. The critical size of these two kinds of flakes can be roughly estimated at âˆ¼17µm. Within the small flakes, the sharp-corner regions show specific strain-modified properties due to the suffering of large tensile strain. While in the large MoS2flakes, the complicated vein-like nanoripple structures were formed due to the interface slipping process under the larger tensile strain. Our work not only demonstrates the size-specific strain behaviors of MoS2flakes but also sheds light on the artificial design and preparation of strain-engineered nanostructures for the devices based on the 2D materials.

Dietary Fiber Protects against Diabetic Nephropathy through Short-Chain Fatty Acid-Mediated Activation of G Protein-Coupled Receptors GPR43 and GPR109A.

BACKGROUND: Studies have reported "dysbiotic" changes to gut microbiota, such as depletion of gut bacteria that produce short-chain fatty acids (SCFAs) through gut fermentation of fiber, in CKD and diabetes. Dietary fiber is associated with decreased inflammation and mortality in CKD, and SCFAs have been proposed to mediate this effect. METHODS: To explore dietary fiber's effect on development of experimental diabetic nephropathy, we used streptozotocin to induce diabetes in wild-type C57BL/6 and knockout mice lacking the genes encoding G protein-coupled receptors GPR43 or GPR109A. Diabetic mice were randomized to high-fiber, normal chow, or zero-fiber diets, or SCFAs in drinking water. We used proton nuclear magnetic resonance spectroscopy for metabolic profiling and 16S ribosomal RNA sequencing to assess the gut microbiome. RESULTS: Diabetic mice fed a high-fiber diet were significantly less likely to develop diabetic nephropathy, exhibiting less albuminuria, glomerular hypertrophy, podocyte injury, and interstitial fibrosis compared with diabetic controls fed normal chow or a zero-fiber diet. Fiber beneficially reshaped gut microbial ecology and improved dysbiosis, promoting expansion of SCFA-producing bacteria of the genera Prevotella and Bifidobacterium, which increased fecal and systemic SCFA concentrations. Fiber reduced expression of genes encoding inflammatory cytokines, chemokines, and fibrosis-promoting proteins in diabetic kidneys. SCFA-treated diabetic mice were protected from nephropathy, but not in the absence of GPR43 or GPR109A. In vitro, SCFAs modulated inflammation in renal tubular cells and podocytes under hyperglycemic conditions. CONCLUSIONS: Dietary fiber protects against diabetic nephropathy through modulation of the gut microbiota, enrichment of SCFA-producing bacteria, and increased SCFA production. GPR43 and GPR109A are critical to SCFA-mediated protection against this condition. Interventions targeting the gut microbiota warrant further investigation as a novel renoprotective therapy in diabetic nephropathy.

Organ- and Age-Specific Differences of Dioscorea polystachya Compounds Measured by UPLC-QTOF/MS.

Dioscorea polystachya, named Chinese yam, is widely cultivated as a functional food and natural medicine in China. There is currently little information about the chemical characteristics of Dioscorea polystachya in different organs (tuber cortex and tuber flesh) and at various ages. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was used to profile chemical compounds in Dioscorea polystachya. As a result, thirty-eight compounds were detected in yam tuber cortex and tuber flesh. More compounds were detected in yam tuber cortex than in tuber flesh. Compounds such as dehydroepiandrosterone, allantoin and flavonoids were selected as biomarker candidates. Dehydroepiandrosterone was found more abundant in tuber flesh, while allantoin and flavonoids showed higher levels in tuber cortex. Furthermore, the levels of dioscin, malvalic acid and sucrose differed significantly among age groups and were highest in the tubers at 2 years. While the levels of allantoin, adenosine and glutamine increased with the growing years and were highest at 4 years. Thus, 2-year old Dioscorea polystachya tubers could be harvested to prepare dioscin, malvalic acid and sucrose supplements. The 4-year-old Dioscorea polystachya tubers would be the best choice for obtaining a large amount of allantoin and adenosine in industrial production.

Neto proteins regulate gating of the kainate-type glutamate receptor GluK2 through two binding sites.

The neuropilin and tolloid-like (Neto) proteins Neto1 and Neto2 are auxiliary subunits of kainate-type glutamate receptors (KARs) that regulate KAR trafficking and gating. However, how Netos bind and regulate the biophysical functions of KARs remains unclear. Here, we found that the N-terminal domain (NTD) of glutamate receptor ionotropic kainate 2 (GluK2) binds the first complement C1r/C1s-Uegf-BMP (CUB) domain of Neto proteins (i.e. NTD-CUB1 interaction) and that the core of GluK2 (GluK2ΔNTD) binds Netos through domains other than CUB1s (core-Neto interaction). Using electrophysiological analysis in HEK293T cells, we examined the effects of these interactions on GluK2 gating, including deactivation, desensitization, and recovery from desensitization. We found that NTD deletion does not affect GluK2 fast gating kinetics, the desensitization, and the deactivation. We also observed that Neto1 and Neto2 differentially regulate GluK2 fast gating kinetics, which largely rely on the NTD-CUB1 interactions. NTD removal facilitated GluK2 recovery from desensitization, indicating that the NTD stabilizes the GluK2 desensitization state. Co-expression with Neto1 or Neto2 also accelerated GluK2 recovery from desensitization, which fully relied on the NTD-CUB1 interactions. Moreover, we demonstrate that the NTD-CUB1 interaction involves electric attraction between positively charged residues in the GluK2_NTD and negatively charged ones in the CUB1 domains. Neutralization of these charges eliminated the regulatory effects of the NTD-CUB1 interaction on GluK2 gating. We conclude that KARs bind Netos through at least two sites and that the NTD-CUB1 interaction critically regulates Neto-mediated GluK2 gating.

Characterization of the Gh4CL gene family reveals a role of Gh4CL7 in drought tolerance.

BACKGROUND: The function of 4-coumarate-CoA ligases (4CL) under abiotic stresses has been studied in plants, however, limited is known about the 4CL genes in cotton (G. hirsutum L.) and their roles in response to drought stress. RESULTS: We performed genome-wide identification of the 4CL genes in G. hirsutum and investigated the expression profiles of the identified genes in various cotton tissues and in response to stress conditions with an aim to identify 4CL gene(s) associated with drought tolerance. We identified 34 putative 4CL genes in G. hirsutum that were clustered into three classes. Genes of the same class usually share a similar gene structure and motif composition. Many cis-elements related to stress and phytohormone responses were found in the promoters of the Gh4CL genes. Of the 34 Gh4CL genes, 26 were induced by at least one abiotic stress and 10 (including Gh4CL7) were up-regulated under the polyethylene glycol (PEG) simulated drought stress conditions. Virus-induced gene silencing (VIGS) in cotton and overexpression (OE) in Arabidopsis thaliana were applied to investigate the biological function of Gh4CL7 in drought tolerance. The Gh4CL7-silencing cotton plants showed more sensitive to drought stress, probably due to decreased relative water content (RWC), chlorophyll content and antioxidative enzyme activity, increased stomatal aperture, and the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2). Arabidopsis lines overexpressing Gh4CL7, however, were more tolerant to drought treatment, which was associated with improved antioxidative enzyme activity, reduced accumulation of MDA and H2O2 and up-regulated stress-related genes under the drought stress conditions. In addition, compared to their respective controls, the Gh4CL7-silencing cotton plants and the Gh4CL7-overexpressing Arabidopsis lines had a ~ 20% reduction and a ~ 10% increase in lignin content, respectively. The expression levels of genes related to lignin biosynthesis, including PAL, CCoAOMT, COMT, CCR and CAD, were lower in Gh4CL7-silencing plants than in controls. Taken together, these results demonstrated that Gh4CL7 could positively respond to drought stress and therefore might be a candidate gene for improvement of drought tolerance in cotton. CONCLUSION: We characterized the 4CL gene family in upland cotton and revealed a role of Gh4CL7 in lignin biosynthesis and drought tolerance.

Characterization and transcriptome analysis of a dominant genic male sterile cotton mutant.

BACKGROUND: Male sterility is an efficient trait for hybrid seed production and germplasm innovation. Until now, most studies on male sterility were on cytoplasmic and recessive genic sterility, with few on dominant genic male sterility, especially in cotton, due to lack of such mutant. RESULTS: We discovered a natural male sterile (MS) Sea Island cotton (G. barbadense) mutant. Genetic analysis showed the mutation was caused by a dominant mutation in a single nuclear gene. Comparative cytological observation of anther sections from MS and wild-type (WT) uncovered cellular differences in anther at and after the tetrad stage of pollen mother cells (PMC). In the MS anthers, the outer wall of pollen grains was free of spinules, the tapetum was vacuolated and showed delayed degradation, consequently, no functional pollen grains. Comparison of transcriptomes from meiosis, tetrad, mononuclear and binuclear pollen, and pollen maturation stages identified 13,783 non-redundant differentially expressed genes (DEGs) between MS and WT. Based on the number of DEGs, analyses of enriched GO terms and KEGG pathways, it was evident that significant transcriptomic changes occurred at and after the tetrad stage, consistent with cytological observation, and that the major differences were on metabolism of starch, sucrose, ascorbate, aldarate, alanine, aspartate and glutamate, and biosynthesis of cutin, suberine and wax. WGCNA analysis identified five modules containing 920 genes highly related to anther development, especially the greenyellow module with 54 genes that was highly associated with PMC meiosis and tetrad formation. A NAC transcription factor (Gh_D11G2469) was identified as a hub gene for this module, which warrants further functional characterization. CONCLUSIONS: We demonstrated that the MS trait was controlled by a single dominant nuclear gene and caused by delayed tapetum degradation at the tetrad stage. Comparative transcriptome analysis and gene network construction identified DEGs, enriched GO terms and metabolic pathways, and hub genes potentially associated with anther development and the MS trait. These results contribute to our understanding of dominant genic male sterility (DGMS) and provided source for innovation of cotton germplasm.

Imaging oxygen molecular adsorption and dissociation on the Ti site of rutile TiO2(110) surface with real configuration at 78 K by atomic force microscopy.

Understanding oxygen adsorption and dissociation on the five-fold coordinated titanium (Ti5c) site of the rutile TiO2 surface is important in clarifying chemical reaction processes. Accordingly, three different configurations of molecularly adsorbed O2, including parallel side-on, inclined side-on and end-on configurations, and their dissociation were directly observed with atomic resolution at 78 K by atomic force microscopy. Our results experimentally demonstrated that the three adsorbed O2 configurations could be changed by electric field stimulation. The initial configurations of the adsorbed O2 and transition of O2 configurations were related to their coverage. On the other hand, the tunneling current stimulation could dissociate these O2 species, indicating that they are precursors for the O adatom (Oad). It is proposed that the effect of electric field stimulation contributes to the transition of these three adsorbed O2 configurations, and the effect of the tunneling current is the main factor for the dissociation of the adsorbed O2. In addition, based on the atomic contrast and height histograms of Oad, different charge states of Oad were observed, which could coexist on the surface region. The present study demonstrates an intuitional observation of O2 adsorption and dissociation on the Ti5c site, and thus is expected to be useful to understand the surface reactions on the oxide surface.