Gene Flow Risks From Transgenic Herbicide-Tolerant Crops to Their Wild Relatives Can Be Mitigated by Utilizing Alien Chromosomes

Integration of a transgene into chromosomes of the C-genomes of oilseed rape (AACC, 2n = 38) may affect their gene flow to wild relatives, particularly Brassica juncea (AABB, 2n = 36). However, no empiric evidence exists in favor of the C-genome as a safer candidate for transformation. In the presence of herbicide selections, the first- to fourth-generation progenies of a B. juncea × glyphosate-tolerant oilseed rape cross [EPSPS gene insertion in the A-genome (Roundup Ready, event RT73)] showed more fitness than a B. juncea × glufosinate-tolerant oilseed rape cross [PAT gene insertion in the C-genome (Liberty Link, event HCN28)]. Karyotyping and fluorescence in situ hybridization–bacterial artificial chromosome (BAC-FISH) analyses showed that crossed progenies from the cultivars with transgenes located on either A- or C- chromosome were mixoploids, and their genomes converged over four generations to 2n = 36 (AABB) and 2n = 37 (AABB + C), respectively. Chromosome pairing of pollen mother cells was more irregular in the progenies from cultivar whose transgene located on C- than on A-chromosome, and the latter lost their C-genome-specific markers faster. Thus, transgene insertion into the different genomes of B. napus affects introgression under herbicide selection. This suggests that gene flow from transgenic crops to wild relatives could be mitigated by breeding transgenic allopolyploid crops, where the transgene is inserted into an alien chromosome

Tip60 Suppresses Cholangiocarcinoma Proliferation and Metastasis via PI3k-AKT

Background/Aims: Aberrant expression of Tip60 is associated with progression in many cancers. However, the role of Tip60 in cancer progression remains contradictory. The aim of this study was to investigate the clinical significance, biological functions and underlying mechanisms of Tip60 deregulation in cholangiocarcinoma (CCA) for the first time. Methods: Quantitative real-time PCR (QRT-PCR), western blotting and immunohistochemistry staining (IHC) were carried out to measure Tip60 expression in CCA tissues and cell lines. Kaplan–Meier analysis and the log-rank test were used for survival analysis. In vitro, cell proliferation was evaluated by flow cytometry and CCK-8, colony formation, and EDU assays. Migration/ invasion was evaluated by trans-well assays. Phosphokinase array was used to confirm the dominant signal regulated by Tip60. Tumor growth and metastasis were demonstrated in vivo using a mouse model. Results: Tip60 was notably downregulated in CCA tissues, which was associated with greater tumor size, venous invasion, and TNM stage. Down-regulation of Tip60 was associated with tumor progression and poorer survival in CCA patients. In vitro and in vivo studies demonstrated that Tip60 suppressed growth and metastasis throughout the progression of CCA. We further identified the PI3K/AKT pathway as a dominant signal of Tip60 and suggested that Tip60 regulated CCA cell proliferation and metastasis via PT3K-AKT pathway. Pearson analysis revealed that PTEN was positively correlated with the Tip60 level in CCA tissues. Conclusion: Tip60, as a tumor suppressor in CCA via the PI3K/AKT pathway, might be a promising therapeutic target or prognostic marker for CCA

Transgene Was Silenced in Hybrids between Transgenic Herbicide-Resistant Crops and Their Wild Relatives Utilizing Alien Chromosomes

The commercialization of transgenic herbicide-resistant (HR) crops may cause gene flow risk. If a transgene in progenies of transgenic crops and wild relatives is silencing, these progenies should be killed by the target herbicide, thus, the gene flow risk could be decreased. We obtained the progenies of backcross generations between wild Brassca juncea (AABB, 2n = 36) and glufosinate-resistant transgenic Brassica napus (AACC, 2n = 38, PAT gene located on the C-chromosome). They carried the HR gene but did not express it normally, i.e., gene silencing occurred. Meanwhile, six to nine methylation sites were found on the promoter of PAT in transgene-silencing progenies, while no methylation sites occurred on that in transgene-expressing progenies. In addition, transgene expressing and silencing backcross progenies showed similar fitness with wild Brassica juncea. In conclusion, we elaborate on the occurrence of transgene-silencing event in backcross progenies between transgenic crop utilizing alien chromosomes and their wild relatives, and the DNA methylation of the transgene promoter was an important factor leading to gene silencing. The insertion site of the transgene could be considered a strategy to reduce the ecological risk of transgenic crops, and applied to cultivate lower gene flow HR crops in the future

Study on Stress Corrosion Characteristics of Drill Rod Joint Under Mechanical Effects

Thanks to the complex underground environment that coal mines enjoy, drill rods for mining are vulnerable to corrosion during operation. To investigate the impact of the corrosion defects on the residual intensity of the drill rod, a relational expression of stress versus corrosion rate in the conditions of uniform and local corrosions is deduced based on the theory on mechanochemical effects; building on this, a spherical corrosion defect is developed in the joint of a φ73 mm drill rod while it is exerted with a make-up torque, an axial force and a bending moment. So it is found that, when the corrosion defect is under pressure, the bending moment plays a certain role to inhibit its increase, however when it is under tension, the bending moment plays the role to drive its increase so as to quicken its corrosion rate while the impact of the change in the corrosion detect depth is much greater than that of the radius. The result from the research provides a basis to evaluate the residual intensity of the drill rod and theoretical basis to protect drill rods from corrosion

Experimental Study of O2-Enriched CO2 Production by BaCo0.8B0.2O3−δ (B=Ce, Al, Fe, Cu) Perovskites Sorbent for Marine Exhaust CO2 Capture Application

An effective approach for reducing CO2 emissions from marine exhaust is adopting oxyfuel combustion technology. A series of B-site doped BaCo0.8B0.2O3−δ (B=Ce, Al, Fe, Cu) perovskites as novel oxygen carrier applications were prepared by the sol-gel method. The oxygen desorption characteristics of the B-site doped BaCo0.8B0.2O3−δ perovskites and the effects of adsorption/desorption temperature, CO2 volume flow rate, CO2 partial pressures, and adsorption time were researched in the fixed bed reactor. The surface morphology and size of the oxygen carrier was observed by scanning electron microscope (SEM). Results showed that BaCo0.8Al0.2O3−δ and BaCo0.8Ce0.2O3−δ have comparable performance, considering the cost of the raw materials. BaCo0.8Al0.2O3−δ was selected as candidate for further study. The optimal adsorption/desorption temperature, CO2 volume flow rate, CO2 partial pressure and adsorption time for BaCo0.8Al0.2O3−δ were studied in detail. Results showed that the best operating parameters were determined to be 850 °C/850 °C for adsorption/desorption temperature, 200 mL/min for CO2 volume flow rate, 100% CO2 partial pressure, and 30 min for absorption time, respectively. Furthermore, multiple cycle results indicate that BaCo0.8Al0.2O3−δ sorbent has high reactivity and cyclic stability

Methanol Steam Reforming over La1-xSrxCeO3-δ Catalysts for Hydrogen Production: Optimization of Operating Parameters

In this study, a series of A-site strontium-doped La1-xSrxCeO3-δ (x = 0.2, 0.4, 0.6, 0.8) perovskite catalysts were synthesized via the ethylenediaminetetraacetic acid (EDTA) sol-gel method for hydrogen production by methanol steam reforming. The fresh and the reduced catalysts are characterized by scanning X-ray (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques. Results showed that La0.6Sr0.4CeO3-δ exhibited the best performance among the La1-xSrxCeO3-δ catalysts. The operating parameters were optimized to study the catalytic performance of La0.6Sr0.4CeO3-δ, including catalytic temperature, water–methanol ratio (W/M) and liquid hourly space velocity (LHSV). However, the excessive strontium content led to a decrease in hydrogen production amount per unit time, and the high W/M promoted the reverse water–gas shift reaction (RWGS), which resulted in a decrease in CO selectivity and an increase in CO2 selectivity. In addition, the optimal reaction parameters are as follows: reforming temperature of 700 °C; W/M of 3:1; LHSV of 20 h−1. Furthermore, the methanol conversion rate of La0.6Sr0.4CeO3-δ can reach approximately 82%, the hydrogen production can reach approximately 3.26 × 10−3 mol/g(cat)/min under the optimum reaction conditions. Furthermore, La0.6Sr0.4CeO3-δ exhibits high hydrogen selectivity (85%), which is a promising catalyst for MSR application

Methanol Steam Reforming over La_1-xSr_xCeO_3-δ Catalysts for Hydrogen Production: Optimization of Operating Parameters

In this study, a series of A-site strontium-doped La1-xSrxCeO3-δ (x = 0.2, 0.4, 0.6, 0.8) perovskite catalysts were synthesized via the ethylenediaminetetraacetic acid (EDTA) sol-gel method for hydrogen production by methanol steam reforming. The fresh and the reduced catalysts are characterized by scanning X-ray (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques. Results showed that La0.6Sr0.4CeO3-δ exhibited the best performance among the La1-xSrxCeO3-δ catalysts. The operating parameters were optimized to study the catalytic performance of La0.6Sr0.4CeO3-δ, including catalytic temperature, water–methanol ratio (W/M) and liquid hourly space velocity (LHSV). However, the excessive strontium content led to a decrease in hydrogen production amount per unit time, and the high W/M promoted the reverse water–gas shift reaction (RWGS), which resulted in a decrease in CO selectivity and an increase in CO2 selectivity. In addition, the optimal reaction parameters are as follows: reforming temperature of 700 °C; W/M of 3:1; LHSV of 20 h−1. Furthermore, the methanol conversion rate of La0.6Sr0.4CeO3-δ can reach approximately 82%, the hydrogen production can reach approximately 3.26 × 10−3 mol/g(cat)/min under the optimum reaction conditions. Furthermore, La0.6Sr0.4CeO3-δ exhibits high hydrogen selectivity (85%), which is a promising catalyst for MSR application

miR-940 Suppresses Tumor Cell Invasion and Migration via Regulation of CXCR2 in Hepatocellular Carcinoma

Aim. To investigate the expression of miR-940 in the hepatocellular carcinoma (HCC) and its impact on function and biological mechanism in the HCC cells. Methods. Quantitative RT-PCR analysis was used to quantify miR-940 expression in 46 cases of tissues and cells. Transfection of HCC cell lines was performed by miR-940 mimics; the abilities of invasion and migration were assessed through Transwell array. Western blot represents the alteration in expression of CXCR2 by miR-940 mimics. Results. miR-940 expression was decreased significantly in the HCC tissues and the relevant cell lines. miR-940 upregulation suppressed the invasion and migration of HCC cells in vitro. Furthermore, the CXCR2 was downregulated to suppress invasion and migration after miR-940 mimics. Moreover, decreased miR-940 expression was negatively correlated with Edmondson grade (P=0.008), tumor microsatellite or multiple tumors (P=0.04), vascular invasion (P=0.035), and recurrence and metastasis (P=0.038). Kaplan-Meier analysis demonstrated that decreased miR-940 expression contributed to poor overall survival (P<0.05). Conclusions. Our findings present that miR-940 acts as a pivotal adaptor of CXCR2 and its transcription downregulated CXCR2 expression to decrease HCC invasion and migration in vitro. Our study suggests that miR-940 may be a novel poor prognostic biomarker for HCC

Centipede KCNQ Inhibitor SsTx Also Targets K_V1.3

It was recently discovered that Ssm Spooky Toxin (SsTx) with 53 residues serves as a key killer factor in red-headed centipede&#8217;s venom arsenal, due to its potent blockage of the widely expressed KCNQ channels to simultaneously and efficiently disrupt cardiovascular, respiratory, muscular, and nervous systems, suggesting that SsTx is a basic compound for centipedes&#8217; defense and predation. Here, we show that SsTx also inhibits KV1.3 channel, which would amplify the broad-spectrum disruptive effect of blocking KV7 channels. Interestingly, residue R12 in SsTx extends into the selectivity filter to block KV7.4, however, residue K11 in SsTx replaces this ploy when toxin binds on KV1.3. Both SsTx and its mutant SsTx_R12A inhibit cytokines production in T cells without affecting the level of KV1.3 expression. The results further suggest that SsTx is a key molecule for defense and predation in the centipedes&#8217; venoms and it evolves efficient strategy to disturb multiple physiological targets