Photosynthetic capacity and assimilate transport of the lower canopy influence maize yield under high planting density.

Photosynthesis is a major trait of interest for development of high-yield crop plants. However, little is known about the effects of high-density planting on photosynthetic responses at the whole-canopy level. Using the high-yielding maize (Zea mays L.) cultivars 'LY66', 'MC670', and 'JK968', we here conducted a two-year field experiment to assess ear development in addition to leaf characteristics and photosynthetic parameters in each canopy layer at four planting densities. Increased planting density promoted high grain yield and population-scale biomass accumulation despite reduced per-plant productivity. MC670 had the strongest adaptability to high-density planting conditions. Physiological analysis showed that increased planting density primarily led to decreases in the single-leaf area above the ear for LY66 and MC670 and below the ear for JK968. Furthermore, high planting density decreased chlorophyll content and the photosynthetic rate due to decreased canopy transmission, leading to severe decreases in single-plant biomass accumulation in the lower canopy. Moreover, increased planting density improved pre-silking biomass transfer, especially in the lower canopy. Yield showed significant positive relationships with photosynthesis and biomass in the lower canopy, demonstrating the important contributions of these leaves to grain yield under dense planting conditions. Increased planting density led to retarded ear development as a consequence of reduced glucose and fructose contents in the ears, indicating reductions in sugar transport that were associated with limited sink organ development, reduced kernel number, and yield loss. Overall, these findings highlighted the photosynthetic capacities of the lower canopy as promising targets for improving maize yield under dense planting conditions.

Cytochrome P450 CYP709C56 metabolizing mesosulfuron-methyl confers herbicide resistance in Alopecurus aequalis.

Multiple herbicide resistance in diverse weed species endowed by enhanced herbicide detoxification or degradation is rapidly growing into a great threat to herbicide sustainability and global food safety. Although metabolic resistance is frequently documented in the economically damaging arable weed species shortawn foxtail (Alopecurus aequalis Sobol.), relevant molecular knowledge has been lacking. Previously, we identified a field population of A. aequalis (R) that had evolved metabolic resistance to the commonly used acetolactate synthase (ALS)-inhibiting herbicide mesosulfuron-methyl. RNA sequencing was used to discover potential herbicide metabolism-related genes, and four cytochrome P450s (CYP709C56, CYP71R18, CYP94C117, and CYP94E14) were identified with higher expressions in the R vs. susceptible (S) plants. Here the full-length P450 complementary DNA transcripts were each cloned with identical sequences between the S and R plants. Transgenic Arabidopsis overexpressing CYP709C56 became resistant to the sulfonylurea herbicide mesosulfuron-methyl and the triazolo-pyrimidine herbicide pyroxsulam. This resistance profile generally but does not completely in accordance with what is evident in the R A. aequalis. Transgenic lines exhibited enhanced capacity for detoxifying mesosulfuron-methyl into O-demethylated metabolite, which is in line with the detection of O-demethylated herbicide metabolite in vitro in transformed yeast. Structural modeling predicted that mesosulfuron-methyl binds to CYP709C56 involving amino acid residues Thr-328, Thr-500, Asn-129, Gln-392, Phe-238, and Phe-242 for achieving O-demethylation. Constitutive expression of CYP709C56 was highly correlated with the metabolic mesosulfuron-methyl resistance in A. aequalis. These results indicate that CYP709C56 degrades mesosulfuron-methyl and its up-regulated expression in A. aequalis confers resistance to mesosulfuron-methyl.

Effect of lathyrol derivatives on non-small cell lung cancer and the possible mechanism. / 千金子二萜醇衍生物抗非小细胞肺癌的作用及机制.

OBJECTIVES: Non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer, with highmorbidity and mortality rate. Nove drug development for NSCLC is urgently needed.This study aims to investigate the activity of lathyrol derivatives and the mechanism for its inhibitory effect on the growth of NSCLC cells. METHODS: Three lathyrol derivatives were synthesized from lathyrol and their structures were verified by nuclear magnetic resonance. MTT assay was used to detect the effects of the lathyrol derivatives on the proliferation activity of NSCLC cells (A549 and H1299 cells), and the compound with the best activity was selected for subsequent experiments. Colony forming assay, wound-healing assay, and transwell assay were applied to detect in vitro cell proliferation, migration and invasion ability in A549 and H1299 cells, respectively. Quantitative real-time RT-PCR and Western blotting were performed to detect mRNA and protein levels of E-cadherin, N-cadherin, ß-catenin, and MMP2 in A549 cells, respectively. RESULTS: Three lathyrol derivatives inhibited the growth of A549 and H1299 cells in a dose-dependent manner, and they showed a weak inhibitory effect on normal cells Beas-2B and 16HBE, indicating that they possessed certain selective toxic effects. Therefore, C-5 benzoylated lathyrol with the best activity was selected as the ideal drug for the subsequent experiments. Compared with the control group, the number and size of cell clusters in the treatment group of A549 and H1299 cells were significantly decreased, the relative mobility were significantly decreased, and the number of invaded cells were significantly decreased (all P<0.05), indicating that the in vitro cell proliferation, migration and invasion ability were decreased. The mRNA levels of integrin α2, integrin ß1, MMP2, MMP9, ß-catenin, and N-cadherin were decreased, while the expression of E-cadherin was increased (all P<0.05). The protein levels of N-cadherin, ß-catenin, MMP2, and integrin αV were decreased, while the expression of E-cadherin was increased (all P<0.05). CONCLUSIONS: The lathyrol derivatives synthesized in this study possess good inhibitory activity against NSCLC. Among them, C-5 benzoylated lathyrol significantly inhibits the proliferation, migration, and invasion ability of NSCLC cells in vitro through regulating the process of epithelial-mesenchymal transition.

S-nitrosoglutathione Reductase-Mediated Nitric Oxide Affects Axillary Buds Outgrowth of Solanum lycopersicum L. by Regulating Auxin and Cytokinin Signaling.

Auxin and cytokinin are two kinds of important phytohormones that mediate outgrowth of axillary buds in plants. How nitric oxide and its regulator of S-nitrosoglutathione reductase (GSNOR) take part in auxin and cytokinin signaling for controlling axillary buds outgrowth remains elusive. We investigated the roles of GSNOR during tomato axillary bud outgrowth by using physiological, biochemical and genetic approaches. GSNOR negatively regulated NO homeostasis. Suppression of GSNOR promoted axillary bud outgrowth by inhibiting the expression of FZY in both apical and axillary buds. Meanwhile, AUX1 and PIN1 were down-regulated in apical buds but up-regulated in axillary buds in GSNOR-suppressed plants. Thus, reduced IAA accumulation was shown in both apical buds and axillary buds of GSNOR-suppressed plants. GSNOR-mediated changes of NO and auxin affected cytokinin biosynthesis, transport, and signaling. And a decreased ratio of auxin: cytokinin was shown in axillary buds of GSNOR-suppressed plants, leading to bud dormancy breaking. We also found that the original NO signaling was generated by nitrate reductase (NR) catalyzing nitrate as substrate. NR-mediated NO reduced the GSNOR activity through S-nitrosylation of Cys-10, then induced a further NO burst, which played the above roles to promote axillary buds outgrowth. Together, GSNOR-mediated NO played important roles in controlling axillary buds outgrowth by altering the homeostasis and signaling of auxin and cytokinin in tomato plants.

Improving photosynthesis to increase grain yield potential: an analysis of maize hybrids released in different years in China.

In this work, we sought to understand how breeding has affected photosynthesis and to identify key photosynthetic indices that are important for increasing maize yield in the field. Our 2-year (2017-2018) field experiment used five high-yielding hybrid maize cultivars (generated in the 1970s, 2000s, and 2010s) and was conducted in the Xinjiang Autonomous Region of China. We investigated the effects of planting density on maize grain yield, photosynthetic parameters, respiration, and chlorophyll content, under three planting density regimens: 75,000, 105,000, and 135,000 plants ha-1. Our results showed that increasing planting density to the medium level (105,000 plants ha-1) significantly increased grain yield (Y) up to 20.32% compared to the low level (75,000 plants ha-1). However, further increasing planting density to 135,000 plants ha-1 did not lead to an additional increase in yield, with some cultivars actually exhibiting an opposite trend. Interestingly, no significant changes in photosynthetic rate, dark respiration, stomatal density, and aperture were observed upon increasing planting density. Moreover, our experiments revealed a positive correlation between grain yield and the net photosynthetic rate (Pn) upon the hybrid release year. Compared to other cultivars, the higher grain yield obtained in DH618 resulted from a higher 1000-kernel weight (TKW), which can be explained by a longer photosynthetic duration, a higher chlorophyll content, and a lower ratio of chlorophyll a/b. Moreover, we found that a higher leaf area per plant and the leaf area index (HI) do not necessarily result in an improvement in maize yield. Taken together, we demonstrated that higher photosynthetic capacity, longer photosynthetic duration, suitable LAI, and higher chlorophyll content with lower chlorophyll a/b ratio are important factors for obtaining high-yielding maize cultivars and can be used for the improvement of maize crop yield.

Microfluidics applications for high-throughput single cell sequencing.

The inherent heterogeneity of individual cells in cell populations plays significant roles in disease development and progression, which is critical for disease diagnosis and treatment. Substantial evidences show that the majority of traditional gene profiling methods mask the difference of individual cells. Single cell sequencing can provide data to characterize the inherent heterogeneity of individual cells, and reveal complex and rare cell populations. Different microfluidic technologies have emerged for single cell researches and become the frontiers and hot topics over the past decade. In this review article, we introduce the processes of single cell sequencing, and review the principles of microfluidics for single cell analysis. Also, we discuss the common high-throughput single cell sequencing technologies along with their advantages and disadvantages. Lastly, microfluidics applications in single cell sequencing technology for the diagnosis of cancers and immune system diseases are briefly illustrated.

Unravelling the effect of two herbicide resistance mutations on acetolactate synthase kinetics and growth traits.

Gene mutations conferring herbicide resistance are hypothesized to have negative pleiotropic effects on plant growth and fitness, which may in turn determine the evolutionary dynamics of herbicide resistance alleles. We used the widespread, annual, diploid grass weed Alopecurus aequalis as a model species to investigate the effect of two resistance mutations-the rare Pro-197-Tyr mutation and the most common mutation, Trp-574-Leu-on acetolactate synthase (ALS) functionality and plant growth. We characterized the enzyme kinetics of ALS from two purified A. aequalis populations, each homozygous for the resistance mutation 197-Tyr or 574-Leu, and assessed the pleiotropic effects of these mutations on plant growth. Both mutations reduced sensitivity of ALS to ALS-inhibiting herbicides without significant changes in extractable ALS activity. The 197-Tyr mutation slightly decreased the substrate affinity (corresponding to an increased Km for pyruvate) and maximum reaction velocity (Vmax) of ALS, whereas the 574-Leu mutation significantly increased these kinetics. Significant decrease or increase in plant growth associated, respectively, with the 197-Tyr and 574-Leu resistance mutations was highly correlated with their impact on ALS kinetics, suggesting more likely persistence of the 574-Leu mutation than the 197-Tyr mutation if herbicide application is discontinued.

Novel missense mutation in VPS33B is associated with isolated low gamma-glutamyltransferase cholestasis: Attenuated, incomplete phenotype of arthrogryposis, renal dysfunction, and cholestasis syndrome.

The typical phenotype of arthrogryposis, renal dysfunction, and cholestasis (ARC) syndrome involves three cardinal symptoms as the name describes, harboring biallelic mutations on VPS33B or VIPAS39. Except for ARC syndrome, low gamma-glutamyltransferase (GGT) cholestasis often implies hereditary hepatopathy of different severity; however, some remain undiagnosed. Several monogenic defects typically with multiorgan manifestations may only present liver dysfunction at times, such as DGUOK defect and AGL defect. Previously, four VPS33B mutated cases were reported without arthrogryposis, or with less severe symptoms and longer lifespan, indicating the possibility of incomplete ARC phenotype of isolated hepatopathy. So we retrospectively reviewed all patients with confirmed VPS33B/VIPARS39 defect in our center and identified three presenting isolated low-GGT cholestasis with intractable pruritus. Distinguished from others with typical ARC phenotype, these patients did not suffer the other two typical characteristics, survived much longer, and shared a novel missense VPS33B variation c.1726T>C, p.Cys576Arg, causing declined protein expression and abolished interaction with VIPAS39 in-vitro. Serum bile acid profiles of our VPS33B/VIPAS39 mutated patients revealed similar changes to primary defect of bile salt export pump, among which those with isolated cholestasis phenotype had a higher level of total secondary bile acids than that with typical ARC phenotype, indicating the partial residual function of VPS33B.

Using Transcriptome to Discover a Novel Melatonin-Induced Sodic Alkaline Stress Resistant Pathway in Solanum lycopersicum L.

Melatonin plays important roles in multiple stress responses. However, the downstream signaling pathway and molecular mechanism are unclear until now. Here, we not only revealed the transcriptional control of melatonin-induced sodic alkaline stress tolerance, but also described a screen for key downstream transcriptional factors of melatonin through transcriptome analysis. The melatonin-induced transcriptional network of hormone, transcriptional factors and functional genes has been established under both control and stress conditions. Among these, six candidates of transcriptional factors have been identified via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Using the virus-induced gene silencing approach, we confirmed that DREB1α and IAA3 were key downstream transcriptional factors of melatonin-induced sodic alkaline stress tolerance at the genetic level. The transcriptions of DREB1α and IAA3 could be activated by melatonin or sodic alkaline treatment. Interestingly, we found that DREB1α could directly upregulate the expression of IAA3 by binding to its promoters. Moreover, several physiological processes of Na+ detoxification, dehydration resistance, high pH buffering and reactive oxygen species scavenging were confirmed to depend or partly depend on DREB1α and IAA3 pathway in melatonin-induced stress tolerance. Taken together, this study suggested that DREB1α and IAA3 are positive resistant modulators, and provided a direct link among melatonin, DREB1α and IAA3 in the sodic alkaline stress tolerance activating in tomato plants.

Unravelling GSNOR-Mediated S-Nitrosylation and Multiple Developmental Programs in Tomato Plants.

Nitric oxide (NO) impacts multiple developmental events and stress responses in plants. S-nitrosylation, regulated by S-nitrosoglutathione reductase (GSNOR), is considered as an important route for NO bioactivity. However, genetic evidence for GSNOR-mediated plant development and S-nitrosylation remains elusive in crop species. Genetic and site-specific nitrosoproteomic approach was used to obtain GSNOR-mediated phenotype and S-nitrosylated network. Knockdown of GSNOR increased the endogenous NO level and S-nitrosylation, resulting in higher germination rate, inhibition of root and hypocotyl growth, decreased photosynthesis, reduced plant growth, altered plant architecture, dysplastic pollen grains, and low fructification rate and fruit yield. For nitrosoproteomic analysis, 395 endogenously S-nitrosylated proteins with 554 S-nitrosylation sites were identified within a wide range of biological processes, especially for energy metabolism. Physiological and exogenous energy-support testing were consistent with the omic result, suggesting that GSNOR-mediated S-nitrosylation of energy metabolism plays key roles in impacting plant growth and development. Taken together, GSNOR is actively involved in the regulation of multiple developmental processes related to agronomically important traits. In addition, our results provide valuable resources and new clues for the study of S-nitrosylation-regulated metabolism in plants.

Defects in myosin VB are associated with a spectrum of previously undiagnosed low γ-glutamyltransferase cholestasis.

Hereditary cholestasis in childhood and infancy with normal serum gamma-glutamyltransferase (GGT) activity is linked to several genes. Many patients, however, remain genetically undiagnosed. Defects in myosin VB (MYO5B; encoded by MYO5B) cause microvillus inclusion disease (MVID; MIM251850) with recurrent watery diarrhea. Cholestasis, reported as an atypical presentation in MVID, has been considered a side effect of parenteral alimentation. Here, however, we report on 10 patients who experienced cholestasis associated with biallelic, or suspected biallelic, mutations in MYO5B and who had neither recurrent diarrhea nor received parenteral alimentation. Seven of them are from two study cohorts, together comprising 31 undiagnosed low-GGT cholestasis patients; 3 are sporadic. Cholestasis in 2 patients was progressive, in 3 recurrent, in 2 transient, and in 3 uncategorized because of insufficient follow-up. Liver biopsy specimens revealed giant-cell change of hepatocytes and intralobular cholestasis with abnormal distribution of bile salt export pump (BSEP) at canaliculi, as well as coarse granular dislocation of MYO5B. Mass spectrometry of plasma demonstrated increased total bile acids, primary bile acids, and conjugated bile acids, with decreased free bile acids, similar to changes in BSEP-deficient patients. Literature review revealed that patients with biallelic mutations predicted to eliminate MYO5B expression were more frequent in typical MVID than in isolated-cholestasis patients (11 of 38 vs. 0 of 13). CONCLUSION: MYO5B deficiency may underlie 20% of previously undiagnosed low-GGT cholestasis. MYO5B deficiency appears to impair targeting of BSEP to the canalicular membrane with hampered bile acid excretion, resulting in a spectrum of cholestasis without diarrhea. (Hepatology 2017;65:1655-1669).

Comprehensive bile acid profiling in hereditary intrahepatic cholestasis: Genetic and clinical correlations.

BACKGROUND & AIMS: Genetic defects causing dysfunction in bile salt export pump (BSEP/ABCB11) lead to liver diseases. ABCB11 mutations alter the bile acid metabolome. We asked whether profiling plasma bile acids could reveal compensatory mechanisms and track genetic and clinical status. METHODS: We compared plasma bile acids in 17 ABCB11-mutated patients, 35 healthy controls and 12 genetically undiagnosed cholestasis patients by ultra-high-performance liquid chromatography/multiple-reaction monitoring-mass spectrometry (UPLC/MRM-MS). We developed an index to rank bile acid hydrophobicity, and thus toxicity, based on LC retention times. We recruited 42 genetically diagnosed hereditary cholestasis patients, of whom 12 were presumed to have impaired BSEP function but carried mutations in genes other than ABCB11, and 8 healthy controls, for further verification. RESULTS: The overall hydrophobicity indices of total bile acids in both the ABCB11-mutated group (11.89 ± 1.07 min) and the undiagnosed cholestasis group (11.46 ± 1.07 min) were lower than those of healthy controls (13.69 ± 0.77 min) (both p < 0.005). This was owing to increased bile acid modifications. Secondary bile acids were detected in patients without BSEP expression, suggesting biliary bile acid secretion through alternative routes. A diagnostic panel comprising lithocholic acid (LCA), tauro-LCA, glyco-LCA and hyocholic acid was identified that could differentiate the ABCB11-mutated cohort from healthy controls and undiagnosed cholestasis patients (AUC=0.946, p < 0.0001) and, in non-ABCB11-mutated cholestasis patients, could distinguish BSEP dysfunction from normal BSEP function (9/12 vs 0/38, p < 0.0000001). CONCLUSIONS: Profiling of plasma bile acids has provided insights into cholestasis alleviation and may be useful for the clinical management of cholestatic diseases.

Hydrogen peroxide produced by NADPH oxidase: a novel downstream signaling pathway in melatonin-induced stress tolerance in Solanum lycopersicum.

The beneficial effects of melatonin on abiotic stress have been demonstrated in several plants. However, little is known about the signal transduction pathway of melatonin involved in the plant stress response. Here, we manipulated the melatonin levels in tomato plants through a chemical approach. The roles of melatonin in stress tolerance were studied by assessing the symptoms, chlorophyll fluorescence and stress-responsive gene expression. Moreover, both chemical and genetic approaches were used to study the roles of hydrogen peroxide (H2 O2 ) in melatonin-induced signal transduction in tomato plants. We found that melatonin activates NADPH oxidase (RBOH) to enhance H2 O2 levels by reducing its S-nitrosylation activity. Furthermore, melatonin-induced H2 O2 accumulation was accompanied by obtainable stress tolerance. Inhibition of RBOH or chemical scavenging of H2 O2 significantly reduced the melatonin-induced defense response, including reduced expression of several stress-related genes (CDPK1, MAPK1, TSPMS, ERF4, HSP80 and ERD15) and reduced antioxidative enzyme activity (SOD, CAT and APX), which were responsible for the stress tolerance. Collectively, these results revealed a novel mechanism in which RBOH activity and H2 O2 signaling are important components of the melatonin-induced stress tolerance in tomato plants.

Downregulation and subcellular distribution of HER2 involved in MDA-MB-453 breast cancer cell apoptosis induced by lapatinib/celastrol combination.

PURPOSE: To investigate the effect and related molecular mechanisms of lapatinib/celastrol combination or single-agent treatment in HER2/neu-overexpressing MDA-MB-453 breast cancer cells. METHODS: The effects of treatment with lapatinib, celastrol or their combination on cell growth were determined using MTT assay. Drug synergy was determined using the combination index (CI) methods derived from Chou-Talalay equations using CalcuSyn software. Apoptotic morphology was observed by fluorescence microscope with Hoechst 33258 staining. Changes of apoptotic and growth pathways-related proteins were analysed by Western blot. The expression of HER2 of cell surface was performed by flow cytometry. Subcellular distribution of HER2 was observed by immunofluorescence study. RESULTS: Combination celastrol and lapatinib produced strong synergy in growth inhibition and apoptosis in comparison to single-agent treatment in HER2/neu-overexpressing MDA-MB-453 cells. Interestingly, compared with celastrol treatment alone, lapatinib/celastrol combination induced more HER2 membrane protein downregulation and ectopic to cytoplasm and nucleus in MDA-MB-453 cells. CONCLUSION: The combination of celastrol and lapatinib could be used as a novel combination regimen which provides a strong anticancer synergy in the treatment of HER2/neu-overexpressing cancer cells.

[What is the optimal oxygen saturation for extremely premature infants? A Meta analysis].

OBJECTIVE: To explore an optimal oxygen saturation for extremely preterm infants based on a systemic review of the published studies. METHODS: A Meta analysis of the published studies by the NeOProM Group which compared the outcomes of extremely preterm infants (gestational age <28 weeks) maintained in either a low (85%-89%) or high (91%-95%) oxygen saturation (SpO2) by using the STATA 12.0. The outcomes measured included the mortality and the incidences of retinopathy of prematurity (ROP), necrotizing enterocolitis of newborn (NEC), broncho-pulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and patent ductus arteriosus (PDA). RESULTS: Three studies were included, in which 2 460 infants were assigned into the low SpO2 group and 2 459 infants in the high SpO2 group. The Meta analysis demonstrated that the risk of mortality before discharge or at the age of 18 months increased in the low SpO2 group compared with the high SpO2 group (RR: 1.19; 95%CI: 1.05-1.35); the risk of ROP decreased in the low SpO2 group (RR: 0.73; 95%CI: 0.53-1.00); the risk of NEC increased in the low SpO2 group (RR: 1.26; 95%CI: 1.06-1.49). There was no significance in the incidences of BPD, IVH and PDA between the two groups. CONCLUSIONS: Maintaining SpO2 at 85%-89% may decrease the incidence of ROP, but increase the mortality rate and the incidence of NEC in extremely premature infants.

Celastrol enhanced the anticancer effect of lapatinib in human hepatocellular carcinoma cells in vitro.

PURPOSE: To investigate whether celastrol could show synergism combined with lapatinib in HepG2 human hepatocellular carcinoma (HCC) cell line in vitro. METHODS: The effects of treatment with lapatinib and/or celastrol on cell growth were determined using MTT assay. Drug synergy was determined using combination index (CI) methods derived from Chou-Talalay equations using CalcuSyn software. Apoptotic morphology was observed by fluorescence microscope with Hoechst 33258 staining. The expression of EGFR of cell surface was performed by flow cytometry. Changes of apoptotic and growth pathways-related proteins were analysed by Western blotting. RESULTS: The combination of celastrol and lapatinib produced strong synergy in growth inhibition and apoptosis in vitro in comparison to single-agent treatments. Moreover, celastrol enhanced the ability of lapatinib to down regulate EGFR protein expression in HepG2 cells. CONCLUSION: These data indicate that the combination of celastrol and lapatinib could be used as a novel combination regimen which could hopefully provide strong anticancer synergy in the treatment of HCC.

Emodin azide methyl anthraquinone derivative induced G0/ G1 arrest in HER2/neu-overexpressing MDA-MB-453 breast cancer cells.

PURPOSE: Our previous data have shown that emodin azide methyl anthraquinone derivative (AMAD) triggered mitochondrial- dependent cell apoptosis involving caspase-8-mediated Bid cleavage, and induced proteasomal degradation of HER2/neu by blocking Her2/neu binding to Hsp90. In the present study, we futher investigated the effect of this compound on the cell cycle and related molecular mechanisms in HER2/neu-overexpressing MDA-MB-453 breast cancer cells. METHODS: The cell cycle distribution was tested by flow cytometry. The expression of cell cycle-related proteins was determined by Western blot analysis; DNA agarose gel electrophoresis was used to examine the apoptosis of MDAMB- 453 cells induced by emodin AMAD. RESULTS: After MDA-MB-453 cells were treated with different concentrations of emodin AMAD for 24 hrs, cells were arrested in G0/G1 phase, and the expression of G0/G1 related proteins c/Myc, Cyclin D1, CDK4 and p-Rb changed. DNA fragmentation appeared on the agarose gel in a concentration- dependent manner. CONCLUSION: Emodin AMAD induced G0/G1 arrest in Her2/ neu-overexpressing MDA-MB-453 cancer cells. This G0/G1 arrest was associated with decreasing protein expression of c-Myc, Cyclin D1, CDK4, and p-Rb.

RNA-seq analysis reveals transcriptome reprogramming and alternative splicing during early response to salt stress in tomato root.

Salt stress is one of the dominant abiotic stress conditions that cause severe damage to plant growth and, in turn, limiting crop productivity. It is therefore crucial to understand the molecular mechanism underlying plant root responses to high salinity as such knowledge will aid in efforts to develop salt-tolerant crops. Alternative splicing (AS) of precursor RNA is one of the important RNA processing steps that regulate gene expression and proteome diversity, and, consequently, many physiological and biochemical processes in plants, including responses to abiotic stresses like salt stress. In the current study, we utilized high-throughput RNA-sequencing to analyze the changes in the transcriptome and characterize AS landscape during the early response of tomato root to salt stress. Under salt stress conditions, 10,588 genes were found to be differentially expressed, including those involved in hormone signaling transduction, amino acid metabolism, and cell cycle regulation. More than 700 transcription factors (TFs), including members of the MYB, bHLH, and WRKY families, potentially regulated tomato root response to salt stress. AS events were found to be greatly enhanced under salt stress, where exon skipping was the most prevalent event. There were 3709 genes identified as differentially alternatively spliced (DAS), the most prominent of which were serine/threonine protein kinase, pentatricopeptide repeat (PPR)-containing protein, E3 ubiquitin-protein ligase. More than 100 DEGs were implicated in splicing and spliceosome assembly, which may regulate salt-responsive AS events in tomato roots. This study uncovers the stimulation of AS during tomato root response to salt stress and provides a valuable resource of salt-responsive genes for future studies to improve tomato salt tolerance.

m6A modification of lncRNA PHKA1-AS1 enhances Actinin Alpha 4 stability and promotes non-small cell lung cancer metastasis.

Cancer is a disease with molecular heterogeneity that is closely related to gene mutations and epigenetic changes. The principal histological subtype of lung cancer is non-small cell lung cancer (NSCLC). Long noncoding RNA (lncRNA) is a kind of RNA that is without protein coding function, playing a critical role in the progression of cancer. In this research, the regulatory mechanisms of lncRNA phosphorylase kinase regulatory subunit alpha 1 antisense RNA 1 (PHKA1-AS1) in the progression of NSCLC were explored. The increased level of N6-methyladenosine (m6A) modification in NSCLC caused the high expression of PHKA1-AS1. Subsequently, high-expressed PHKA1-AS1 significantly facilitated the proliferation and metastasis of NSCLC cells, and these effects could be reversed upon the inhibition of PHKA1-AS1 expression, both in vivo and in vitro. Additionally, the target protein of PHKA1-AS1 was actinin alpha 4 (ACTN4), which is known as an oncogene. Herein, PHKA1-AS1 could enhance the protein stability of ACTN4 by inhibiting its ubiquitination degradation process, thus exerting the function of ACTN4 in promoting the progress of NSCLC. In conclusion, this research provided a theoretical basis for further exploring the potential mechanism of NSCLC metastasis and searching novel biomarkers related to the pathogenesis and progression of NSCLC.

Triterpenoid pristimerin induced HepG2 cells apoptosis through ROS-mediated mitochondrial dysfunction.

PURPOSE: To investigate the anticancer properties implicated in a natural triterpenoid (pristimerin)-induced apoptosis and inhibited proliferation in human hepatocellular carcinoma (HCC) HepG2 cell line. METHODS: The cytotoxic activity of pristimerin in HepG2 cells was determined by MTT assay. Apoptotic morphology was observed by fluorescence microscope with Hoechst 33258 staining and percent apoptosis was measured by annexin V/PI double staining. DiOC6 for mitochondrial potential (ΔΨm) and DCFH-DA for reactive oxygen species (ROS) were determined by flow cytometry. Changes of apoptotic- related proteins were analysed by Western blot. RESULTS: Pristimerin exerted a potent cytotoxic effect on HepG2 cells. After HepG2 cells were treated with pristimerin, typical apoptotic bodies, increasing the proportion of apoptotic annexin V-positive cells and activation of caspase-3 were detected in a dose-dependent manner. It was intriguing that pristimerin increased the generation of ROS with a collapse of the mitochondrial membrane potential in the cells. In addition, there was significant change in other mitochondrial membrane proteins triggered by pristimerin, such as Bcl-2 and Bax. Pristimerin also effectively induced subsequent release of cytochrome C from mitochondria into the cytosol, downregulated EGFR protein expression and inhibited downstream signaling pathways in HepG2 cells. Pretreatment with N-acetylcysteine (NAC) blocked ROS generation and resulted in loss of mitochondrial membrane potential, release of cytochrome C and apoptosis induced by pristimerin. CONCLUSION: These data indicate that ROS play an essential role in the induction of apoptosis by pristimerin in HepG2 cells.