Neuronal Activity Promotes Glioma Growth through Neuroligin-3 Secretion.

Active neurons exert a mitogenic effect on normal neural precursor and oligodendroglial precursor cells, the putative cellular origins of high-grade glioma (HGG). By using optogenetic control of cortical neuronal activity in a patient-derived pediatric glioblastoma xenograft model, we demonstrate that active neurons similarly promote HGG proliferation and growth in vivo. Conditioned medium from optogenetically stimulated cortical slices promoted proliferation of pediatric and adult patient-derived HGG cultures, indicating secretion of activity-regulated mitogen(s). The synaptic protein neuroligin-3 (NLGN3) was identified as the leading candidate mitogen, and soluble NLGN3 was sufficient and necessary to promote robust HGG cell proliferation. NLGN3 induced PI3K-mTOR pathway activity and feedforward expression of NLGN3 in glioma cells. NLGN3 expression levels in human HGG negatively correlated with patient overall survival. These findings indicate the important role of active neurons in the brain tumor microenvironment and identify secreted NLGN3 as an unexpected mechanism promoting neuronal activity-regulated cancer growth.

Depletion of CPNE7 sensitizes colorectal cancer to 5-fluorouracil by downregulating ATG9B expression.

We aimed to explore the biological function of CPNE7 and determine the impact of CPNE7 on chemotherapy resistance in colorectal cancer (CRC) patients. According to the Gene Expression Profiling Interactive Analysis database and previously published data, CPNE7 was identified as a potential oncogene in CRC. RT-qPCR and Western blotting were performed to verify the expression of CPNE7. Chi-square test was used to evaluate the associations between CPNE7 and clinical features. Cell proliferation, colony formation, cell migration and invasion, cell cycle and apoptosis were assessed to determine the effects of CPNE7. Transcriptome sequencing was used to identify potential downstream regulatory genes, and gene set enrichment analysis was performed to investigate downstream pathways. The effect of CPNE7 on 5-fluorouracil chemosensitivity was verified by half maximal inhibitory concentration (IC50). Subcutaneous tumorigenesis assay was used to examine the role of CPNE7 in sensitivity of CRC to chemotherapy in vivo. Transmission electron microscopy was used to detect autophagosomes. CPNE7 was highly expressed in CRC tissues, and its expression was correlated with T stage and tumour site. Knockdown of CPNE7 inhibited the proliferation and colony formation of CRC cells and promoted apoptosis. Knockdown of CPNE7 suppressed the expression of ATG9B and enhanced the sensitivity of CRC cells to 5-fluorouracil in vitro and in vivo. Knockdown of CPNE7 reversed the induction of the autophagy pathway by rapamycin and reduced the number of autophagosomes. Depletion of CPNE7 attenuated the malignant proliferation of CRC cells and enhanced the chemosensitivity of CRC cells to 5-fluorouracil.

Deubiquitylase USP7 plays a crucial role in the lineage differentiation of preimplantation blastocysts.

Preimplantation embryos undergo a series of important biological events, including epigenetic reprogramming and lineage differentiation, and the key genes and specific mechanisms that regulate these events are critical to reproductive success. USP7 is a deubiquitinase involved in the regulation of a variety of cellular functions, yet its precise function and mechanism in preimplantation embryonic development remain unknown. Our results showed that RNAi-mediated silencing of USP7 in mouse embryos or treatment with P5091, a small molecule inhibitor of USP7, significantly reduced blastocyst rate and blastocyst quality, and decreased total and TE cell numbers per blastocyst, as well as destroying normal lineage differentiation. The results of single-cell RNA-seq, RT-qPCR, western blot, and immunofluorescence staining indicated that interference with USP7 caused failure of the morula-to-blastocyst transition and was accompanied by abnormal expression of key genes (Cdx2, Oct4, Nanog, Sox2) for lineage differentiation, decreased transcript levels, increased global DNA methylation, elevated repressive histone marks (H3K27me3), and decreased active histone marks (H3K4me3 and H3K27ac). Notably, USP7 may regulate the transition from the morula to blastocyst by stabilizing the target protein YAP through the ubiquitin-proteasome pathway. In conclusion, our results suggest that USP7 may play a crucial role in preimplantation embryonic development by regulating lineage differentiation and key epigenetic modifications.

Single-cell transcriptomics uncovers cellular architecture and developmental trajectories in hepatoblastoma.

BACKGROUND AND AIMS: Hepatoblastoma (HB) is the predominant type of childhood liver cancer. Treatment options for the clinically advanced HB remain limited. We aimed to dissect the cellular and molecular basis underlying HB oncogenesis and heterogeneity at the single-cell level, which could facilitate a better understanding of HB at both the biological and clinical levels. APPROACH AND RESULTS: Single-cell transcriptome profiling of tumor and paired distal liver tissue samples from five patients with HB was performed. Deconvolution analysis was used for integrating the single-cell transcriptomic profiles with the bulk transcriptomes of our HB cohort of post-neoadjuvant chemotherapy tumor samples. A single-cell transcriptomic landscape of early human liver parenchymal development was established for exploring the cellular root and hierarchy of HB oncogenesis. As a result, seven distinct tumor cell subpopulations were annotated, and an effective HB subtyping method was established based on their compositions. A HB tumor cell hierarchy was further revealed to not only fit with the classical cancer stem cell (CSC) model but also mirror the early human liver parenchymal development. Moreover, FACT inhibition, which could disrupt the oncogenic positive feedback loop between MYC and SSRP1 in HB, was identified as a promising epigenetic-targeted therapeutic strategy against the CSC-like HB1-Pro-like1 subpopulation and its related high-risk "Pro-like1" subtype of HB. CONCLUSIONS: Our findings illustrate the cellular architecture and developmental trajectories of HB via integrative bulk and single-cell transcriptome analyses, thus establishing a resourceful framework for the development of targeted diagnostics and therapeutics in the future.

Inhibition of USP21 leads to ovarian carcinoma cell death by suppressing MAPK signaling.

Ovarian cancer is the most aggressive and lethal of all gynecologic malignancies. Although the overexpression (OE) of ubiquitin-specific peptidase 21 (USP21) has been observed in multiple cancers, its expression profile and biological function in ovarian cancer remain unknown. The expression levels of USP21 in ovarian cancer cells and tissues as well as adjacent normal tissues were assessed by qRT-PCR or Western blot assay. The biological function of USP21 in ovarian cancer cells was assessed by cell growth assay in vitro and a tumor growth model in vivo. Our study revealed that USP21 was markedly elevated in ovarian carcinoma tissues compared with adjacent normal tissues. Downregulation of USP21 attenuated the expression levels of MEK2 and p-ERK1/2. Depletion of USP21 resulted in suppressed cell growth of ovarian cancers in vitro and inhibited tumor growth in vivo. Conversely, OE of USP21 promoted the cell proliferation of ovarian cancers and conferred resistance to BAY 11-7082. These findings provide evidences supporting the notion of USP21 as a promising therapeutic target for the treatment of ovarian cancer.

IFN-beta and EIF2AK2 are potential biomarkers for interstitial lung disease in anti-MDA5 positive dermatomyositis.

OBJECTIVE: DM with positive anti-melanoma differentiation-related gene 5 (MDA5) antibody is an autoimmune disease with multiple complications. Interstitial lung diseases (ILDs) are significantly associated with DM and are particularly related to MDA5+ DM. This article aims to explore potential molecular mechanisms and develop new diagnostic biomarkers for MDA5+ DM-ILD. METHODS: The series matrix files of DM and non-specific interstitial pneumonia (NSIP) were downloaded from the Gene Expression Omnibus (GEO) database to identify the differentially expressed genes (DEGs). Gene set enrichment analysis (GSEA) was used to screen the common enriched pathways related to DM and NSIP. Next, the co-expressed differential expressed genes (co-DEGs) between MDA5+, MDA5- and NSIP groups were identified by Venn plots, and then selected for different enrichment analyses and protein-protein interaction (PPI) network construction. The mRNA expression levels of IFN-beta and EIF2AK2 were measured by RT-qPCR. The protein expression levels of IFN-beta were measured by ELISA. RESULTS: Using GSEA, the enriched pathway 'herpes simplex virus 1 infection' was both up-regulated in DM and NSIP. Enrichment analysis in MDA5+ DM, MDA5- DM and NSIP reported that the IFN-beta signalling pathway was an important influencing factor in the MDA5+ DM-ILD. We also identified that eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2) was an important gene signature in the MDA5+ DM-ILD by PPI analysis. The expression levels of IFN-beta and EIF2AK2 were significantly increased in MDA5+ DM-ILD patients. CONCLUSIONS: IFN-beta and EIF2AK2 contributed to the pathogenesis of MDA5+ DM-ILD, which could be used as potential therapeutic targets.

Optimal weak measurement scheme for chiral molecular detection based on photonic spin Hall effect.

In this paper, we propose a precision method to measure the chiroptical signal of Artemisinin solutions using the photonic spin Hall effect (PSHE) on the Ce:YIG-YIG-SiO2 structure as a probe. The effects of transmission distance, incident angles, applied magnetic fields of different directions, and beam waist of light on the weak measurement system are analytically investigated through simulations. It is found that decreasing the beam waist of the incident spot, increasing the incident angle, increasing the transmission distance, and adding a longitudinal magnetic field is conducive to enhancing the amplification transverse shift of PSHE, thus the measurement sensitivity is greatly improved. Based on the optimal weak measurement scheme, the detection limit for concentration measurement of artemisinin based on optical rotatory (OR) was reduced to 0.05 mg/ml. The measurement precision of the OR angle has been improved to 10-7rad.

Amelioration of cadmium cytotoxicity to human cells by nutrient cation contents and the building of a biotic ligand model.

A variety of important major and trace elements may competitively inhibit cadmium (Cd) absorption in human cells and reduce Cd toxicity. However, the impact of essential elements on the cytotoxicity of metals can be difficult to quantify and anticipate. Cd acute toxicity to Caco-2 cell viability was studied in culture solutions and modeled by a biotic ligand model (BLM). The individual effects of the cations potassium (K+), calcium (Ca2+), magnesium (Mg2+), ferrous ion(Fe2+), zinc (Zn2+) and manganese (Mn2+) on Cd toxicity were also investigated. The results indicated that the toxicity of Cd in culture solutions to cell viability declined with increasing concentrations of Zn2+ and Mn2+ in the solutions, while K+, Ca2 +, Mg2 + and Fe2+ had no significant effect. Using the BLM, the stability constants for the binding of Cd2 +, Zn2+, and Mn2+ to biotic ligands were determined to be logKCdBL = 5.76, logKZnBL = 4.39 and logKMnBL = 5.31, respectively. Moreover, it was calculated that 51% occupancy of the biotic ligand sites for Cd by Cd was required to cause a 50% reduction in Caco-2 cell viability. A BLM was successfully established using the estimated constants to predict the Cd cytotoxicity to Caco-2 cell viability as a function of solution characteristics, so that the effective concentrations that reduced cell viability by 50% (EC50) could be predicted by the BLM within 1.6 fold changes of the observed EC50. The application's viability and precision for foretelling Cd toxicity in Caco-2 cells are discussed.

Graph Reinforcement Learning-Based Decision-Making Technology for Connected and Autonomous Vehicles: Framework, Review, and Future Trends.

The proper functioning of connected and autonomous vehicles (CAVs) is crucial for the safety and efficiency of future intelligent transport systems. Meanwhile, transitioning to fully autonomous driving requires a long period of mixed autonomy traffic, including both CAVs and human-driven vehicles. Thus, collaborative decision-making technology for CAVs is essential to generate appropriate driving behaviors to enhance the safety and efficiency of mixed autonomy traffic. In recent years, deep reinforcement learning (DRL) methods have become an efficient way in solving decision-making problems. However, with the development of computing technology, graph reinforcement learning (GRL) methods have gradually demonstrated the large potential to further improve the decision-making performance of CAVs, especially in the area of accurately representing the mutual effects of vehicles and modeling dynamic traffic environments. To facilitate the development of GRL-based methods for autonomous driving, this paper proposes a review of GRL-based methods for the decision-making technologies of CAVs. Firstly, a generic GRL framework is proposed in the beginning to gain an overall understanding of the decision-making technology. Then, the GRL-based decision-making technologies are reviewed from the perspective of the construction methods of mixed autonomy traffic, methods for graph representation of the driving environment, and related works about graph neural networks (GNN) and DRL in the field of decision-making for autonomous driving. Moreover, validation methods are summarized to provide an efficient way to verify the performance of decision-making methods. Finally, challenges and future research directions of GRL-based decision-making methods are summarized.

Trust game, survey trust, are they correlated? Evidence from China.

Trust Game and survey trust are the two most popular measurements in the field of trust research, but most studies conducted in developing countries have found low or even insignificant correlations between them, we therefore validated this phenomenon in the cultural context of the largest developing country, China. Within-country differences can be of the same magnitude as the between country differences, especially in a culturally diverse China. Thus, we focus on comparing the characteristics of trust in the South and North regions of China. Through zero-order correlation and hierarchical regression analysis, our findings are consistent with those of numerous developing countries: Trust Game is lowly correlated with in-group trust survey and not with out-group trust survey. On the other hand, we found that Chinese individuals exhibit a distinct pattern of in-group trust, and there is no fundamental difference in the characteristics of trust between the South and the North.

DEEP GREEN PANICLE1 suppresses GOLDEN2-LIKE activity to reduce chlorophyll synthesis in rice glumes.

Understanding the regulation mechanisms of photosynthesis is key to improving its efficiency and, ultimately, crop yield. In this study, we report that DEEP GREEN PANICLE1 (DGP1) is involved in photosynthesis regulation in rice (Oryza sativa L.). We identified the dgp1 mutant, which has increased chlorophyll content in glumes. The mutated gene was isolated by map-based cloning. Knockout plants, generated using a gene editing approach, mimic the phenotype of dgp1. Overexpression of DGP1 leads to chlorotic leaves and glumes. DGP1 is a plant-specific protein with a conserved TIGR01589 domain. The expression of DGP1 was detected in green tissues and is induced by light. Moreover, genes involved in key steps of chlorophyll synthesis are upregulated in the glumes of dgp1. Importantly, we found that DGP1 interacts with the rice proteins GOLDEN2-LIKE1 (OsGLK1) and GOLDEN2-LIKE2 (OsGLK2), the two transcription factors involved in the regulation of photosynthesis. Transactivation assays showed that DGP1 represses the activation activity of OsGLK1 on its target genes. Our results demonstrate that DGP1 is a repressor of OsGLK activity and thus photosynthesis in rice. Manipulation of this gene and its homologs in other crops may provide new approaches for high photosynthetic efficiency breeding.

Multi-channel optical sensing system with a BP-ANN for heavy metal detection.

A multi-channel optical sensing system for heavy metal concentration detection is presented in this paper. The system utilizes a multi-channel optical path combined with a unique circuit design and BP neural network (BP-ANN) to perform the online analysis of multi-wavelength signals, achieving accurate concentration detection of a heavy metal solution. An array photodiode is used to detect the transmission light intensities at multiple wavelengths through the optical path of the system, which enables the collection of useful spectral information of the solution. The system uses a unique signal acquisition method to effectively improve the efficiency of both signal acquisition and operation. BP-ANN is applied to the online analysis of multi-channel information, which overcomes the influential issue of nonlinear effect on data detection, optimizes the anti-interference ability, and lowers the detection limit of the system. This system eliminates the necessary employment of the expensive and large spectrometers and therefore greatly reduces the instrument cost and occupying space. Additionally, the detection limit of the system is extended lower than that of the conventional spectrophotometer. Compared with the detection limits of heavy metal solution obtained by using a single characteristic light wavelength, the detection limits of Cd2+, Cu2+ and Cr6+ achieved through using multi-channel detection system can be reduced by 42.64%, 38.12%, and 20.62%, respectively, and these detection limits are found as 0.0041mg/L, 0.0091mg/L, and 0.0112mg/L, respectively.

Methylated ZNF582 as a triage marker for occult cervical cancer and advanced cervical intraepithelial neoplasia.

Aim: To explore the appropriate triage methods for women infected with high-risk human papillomavirus (hrHPV). Materials & methods: A total of 424 out of 872 hrHPV-infected women were divided into cervicitis (n = 123), cervical intraepithelial neoplasia grade 1 (CIN1; n = 89), CIN2 (n = 72), CIN3 (n = 87) and cervical cancer (n = 53) groups. Results: The sensitivity/specificity of ZNF582m, PAX1m and liquid-based cytology (LBC) for hrHPV-infected women with transformation zone 3 CIN3+ was 83.9/93.1, 77.4/90.6 and 80.6/58.5%, respectively. The ZNF582m/PAX1m test had a higher specificity than LBC (p < 0.001) and similar sensitivity to that observed for LBC (p > 0.05). ZNF582m/PAX1m improved the positive predictive value of CIN3+ (64.7/60.0%) in low-grade LBC (negative predictive value: 91.7/88.7%). Conclusion: ZNF582m was superior to PAX1m and LBC tests in detecting CIN3+ in hrHPV-infected women.

Human papillomavirus (HPV) testing is the main method for cervical cancer screening. Although most HPV infections are transient and can be cleared by the body, persistent infection with HPV can lead to cervical cancer. In this study, 424 HPV-infected women were divided into normal, cervical intraepithelial neoplasia grade 1 (CIN1), CIN2, CIN3 and cervical cancer groups according to the grade of cervical lesion (low to high). Women with CIN3 or cervical cancer need treatment. ZNF582^m, PAX1^m and liquid-based cytology detected 83.9, 77.4 and 80.6% of women with CIN3+ and 93.1, 90.6 and 58.5% of women without CIN3+. However, the ZNF582^m test was superior to the PAX1^m and liquid-based cytology tests.

Management of patients with positive margin after conization for high-grade cervical intraepithelial lesions.

BACKGROUND AND OBJECTIVE: To evaluate the clinical efficacy and safety of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of patients with positive margin in comparison to regular follow-up, and a repeat cervical conization. MATERIALS AND METHODS: A retrospective analysis was conducted using 83 patients with pathologically confirmed high-grade cervical intraepithelial neoplasia (CIN) with a positive margin after conization. The management methods and patient prognosis were analyzed and compared. RESULTS: Thirty-five, 33, and 15 patients were treated for regular follow-up, ALA-PDT, and a repeat cervical conization, respectively. About 33.3% (5/15) patients had residual lesions of low-grade CIN and above after recognization. The clinical characteristics of patients in the three groups were similar. The residual lesion rates of patients selected for follow-up, ALA-PDT, and recognization were 34.3% (12/35), 9.1% (3/33), and 0% (0/15), respectively, at 6-month follow-up (p = 0.004). The HPV clearance rates were 31.3%, 66.7%, and 84.6%, respectively (p = 0.01). Further analysis showed that a positive margin in the inscribed margin of the cervical canal (p = 0.022) and persistent HR-HPV positive tests after initial conization (p = 0.003) significantly increased the risk of residual disease. At 2-year follow-up, the recurrence rates of lesions were 3.3% and 26.1% in the ALA-PDT and follow-up groups, respectively (p = 0.021). Notably, the recurrence rates were not significantly different between the ALA-PDT and recognization groups (3.3% vs. 6.7%) (p = 0.561). CONCLUSION: ALA-PDT is an effective treatment for patients with a positive margin after cervical conization for high-grade CIN. Compared with regular follow-up, ALA-PDT can reduce residual and recurrence rate. Moreover, there was no significant difference in the efficacy between AlA-PDT and recognization.

CDK7 inhibition suppresses aberrant hedgehog pathway and overcomes resistance to smoothened antagonists.

The aberrant hedgehog (Hh) pathway plays important roles in multiple cancer types, therefore serving as a promising drug target. Current clinically available hedgehog-targeted drugs act mostly by antagonizing the upstream component smoothened; however, both primary and acquired resistance to FDA-approved smoothened inhibitor (SMOi) drugs have been described. We have recently demonstrated that the BET inhibitor effectively suppresses SMOi-resistant Hh-driven cancers through antagonizing transcription of GLI1 and GLI2, the core transcriptional factors of Hh pathway, suggesting epigenetic or transcriptional targeted therapy represents an anti-Hh therapeutic strategy that can overcome SMOi resistance. Here we performed an unbiased screening of epigenetic or transcriptional targeted small molecules to test their inhibitory effects on GLI1 and GLI2 transcription or cell viability of Hh-driven tumor lines. THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), is identified as the top hit in our screening. We then confirmed that antagonizing CDK7 by either small-molecule inhibitors or the CRISPR-Cas9 approach causes substantial suppression of GLI1 and GLI2 transcription, resulting in effective inhibition of Hh-driven cancers in vitro and in vivo. More importantly, antagonizing CDK7 retains inhibitory activity against Hh-driven cancers with almost all so-far described primary or acquired SMOi resistance. Furthermore, we reveal a synergy between CDK7 inhibition and BET inhibition on antagonizing aberrant Hh pathway and Hh-driven cancers that are either responsive or resistant to SMOi. Our results illustrate transcriptional inhibition through targeting CDK7 as a promising therapeutic strategy for treating Hh-driven cancers, especially those with primary or acquired resistance to SMOi drugs.

COM1, a factor of alternative non-homologous end joining, lagging behind the classic non-homologous end joining pathway in rice somatic cells.

The role of rice (Oryza sativa) COM1 in meiotic homologous recombination (HR) is well understood, but its part in somatic double-stranded break (DSB) repair remains unclear. Here, we show that for rice plants COM1 conferred tolerance against DNA damage caused by the chemicals bleomycin and mitomycin C, while the COM1 mutation did not compromise HR efficiencies and HR factor (RAD51 and RAD51 paralogues) localization to irradiation-induced DSBs. Similar retarded growth at the post-germination stage was observed in the com1-2 mre11 double mutant and the mre11 single mutant, while combined mutations in COM1 with the HR pathway gene (RAD51C) or classic non-homologous end joining (NHEJ) pathway genes (KU70, KU80, and LIG4) caused more phenotypic defects. In response to γ-irradiation, COM1 was loaded normally onto DSBs in the ku70 mutant, but could not be properly loaded in the MRE11RNAi plant and in the wortmannin-treated wild-type plant. Under non-irradiated conditions, more DSB sites were occupied by factors (MRE11, COM1, and LIG4) than RAD51 paralogues (RAD51B, RAD51C, and XRCC3) in the nucleus of wild-type; protein loading of COM1 and XRCC3 was increased in the ku70 mutant. Therefore, quite differently to its role for HR in meiocytes, rice COM1 specifically acts in an alternative NHEJ pathway in somatic cells, based on the Mre11-Rad50-Nbs1 (MRN) complex and facilitated by PI3K-like kinases. NHEJ factors, not HR factors, preferentially load onto endogenous DSBs, with KU70 restricting DSB localization of COM1 and XRCC3 in plant somatic cells.

Using quantitative ion character-activity relationship (QICAR) method in evaluation of metal toxicity toward wheat.

It is important to assess the toxic effects posed by soil pollutants toward plants. However, plant toxicology experiments normally involve a considerable amount of manpower, consumables and time. Therefore, the use of metal toxicity prediction models, independent of toxicity tests, is critical. In this study, we investigated the toxicity of different metal ions to wheat using hydroponic experiments. We employed the methods of soft-hard ion grouping, soft-hard ligand theory and K (conditional binding constant based on the biotic ligand model principle) in combination with hydroponic experiments to explore the application of quantitative ion character-activity relationships in predicting phytotoxicity. The results showed that the toxicity of the 19 metal ions tested varied significantly, with EC50 ranging from 0.27 µM to 4463.36 µM. The linear regression relationships between the toxicity of these metal ions and their physicochemical properties were poor (R2 = 0.237-0.331, p < 0.05). These relationships were improved after grouping the metals according to the soft-hard theory (R2 = 0.527-0.744 and p < 0.05 for soft ions; R2 = 0.445-0.743 and p < 0.05 for hard ions). The application of soft-hard ligand theory, based on the binding affinity of the metals to the ligands, showed poor prediction of the phytotoxicity of metals, with R2 = 0.413 (p = 0.024) for the softness consensus scale (σCon) and R2 = 0.348 (p = 0.218) for the normalized hard ligands scale (HLScale). However, the method of K provided the closest fit in predicting toxicity (R2 = 0.803, p < 0.001). Our results showed that the application of soft-hard ion grouping and log K can improve prediction of the phytotoxicity of metals relatively well, which can potentially be used for deriving the toxicity of elements with limited toxicity data.

Transcript level is a key factor affecting RNAi efficiency.

Efficiency is the basis for the application of RNA interference (RNAi) technology. Actually, RNAi efficiency varies greatly among insect species, tissues and genes. Previous efforts have revealed the mechanisms for variation among insect species and tissues. Here, we investigated the reason for variable efficiency among the target genes in the same insect. First, we tested the genes sampled randomly from Tribolium castaneum, Locusta migratoria and Drosophila S2 cells for both their expression levels and sensitivity to RNAi. The results indicated that the genes with higher expression levels were more sensitive to RNAi. Statistical analysis showed that the correlation coefficients between transcript levels and knockdown efficiencies were 0.8036 (n = 90), 0.7255 (n = 18) and 0.9505 (n = 13), respectively in T. castaneum, L. migratoria and Drosophila S2 cells. Subsequently, ten genes with varied expression level in different tissues (midgut and carcass without midgut) of T. castaneum were tested. The results indicated that the higher knockdown efficiency was always obtained in the tissue where the target gene expressed higher. In addition, three genes were tested in different developmental stages, larvae and pupae of T. castaneum. The results found that when the expression level increased after insect pupation, these genes became more sensitive to RNAi. Thus, all the proofs support unanimously that transcript level is a key factor affecting RNAi sensitivity. This finding allows for a better understanding of the RNAi efficiency variation and lead to effective or efficient use of RNAi technology.

OsPINOID Regulates Stigma and Ovule Initiation through Maintenance of the Floral Meristem by Auxin Signaling.

Stigma and ovule initiation is essential for sexual reproduction in flowering plants. However, the mechanism underlying the initiation of stigma and ovule primordia remains elusive. We identified a stigma-less mutant of rice (Oryza sativa) and revealed that it was caused by the mutation in the PINOID (OsPID) gene. Unlike the pid mutant that shows typical pin-like inflorescences in maize (Zea mays) and Arabidopsis (Arabidopsis thaliana), the ospid mutant does not display any defects in inflorescence development and flower initiation, and fails to develop normal ovules in most spikelets. The auxin activity in the young pistil of ospid was lower than that in the wild-type pistil. Furthermore, the expression of most auxin response factor genes was down-regulated, and OsETTIN1, OsETTIN2, and OsMONOPTEROS lost their rearrangements of expression patterns during pistil and stamen primordia development in ospid Moreover, the transcription of the floral meristem marker gene, OSH1, was down-regulated and FLORAL ORGAN NUMBER4, the putative ortholog of Arabidopsis CLAVATA3, was up-regulated in the pistil primordium of ospid These results suggested that the meristem proliferation in the pistil primordium might be arrested prematurely in ospid Based on these results, we propose that the OsPID-mediated auxin signaling pathway plays a crucial role in the regulation of rice stigma and ovule initiation by maintaining the floral meristem.

On-Orbit Calibration of Installation Matrix between Remote Sensing Camera and Star Camera Based on Vector Angle Invariance.

To achieve photogrammetry without ground control points (GCPs), the precise measurement of the exterior orientation elements for the remote sensing camera is particularly important. Currently, the satellites are equipped with a GPS receiver, so that the accuracy of the line elements of the exterior orientation elements could reach centimeter-level. Furthermore, the high-precision angle elements of the exterior orientation elements could be obtained through a star camera which provides the direction reference in the inertial coordinate system and star images. Due to the stress release during the launch and the changes of the thermal environment, the installation matrix is variable and needs to be recalibrated. Hence, we estimate the cosine angle vector invariance of a remote sensing camera and star camera which are independent of attitude, and then we deal with long-term on-orbit data by using batch processing to realize the accurate calibration of the installation matrix. This method not only removes the coupling of attitude and installation matrix, but also reduces the conversion error of multiple coordinate systems. Finally, the geo-positioning accuracy in planimetry is remarkably higher than the conventional method in the simulation results.