Corrigendum: High expression of PARP1 in tumor and stroma cells predicts prognosis and platinum resistance in patients with advanced epithelial ovarian cancer.

[This corrects the article DOI: 10.3389/fonc.2022.931445.].

The PPR-Domain Protein SOAR1 Regulates Salt Tolerance in Rice.

Previous studies in Arabidopsis reported that the PPR protein SOAR1 plays critical roles in plant response to salt stress. In this study, we reported that expression of the Arabidopsis SOAR1 (AtSOAR1) in rice significantly enhanced salt tolerance at seedling growth stage and promoted grain productivity under salt stress without affecting plant productivity under non-stressful conditions. The transgenic rice lines expressing AtSOAR1 exhibited increased ABA sensitivity in ABA-induced inhibition of seedling growth, and showed altered transcription and splicing of numerous genes associated with salt stress, which may explain salt tolerance of the transgenic plants. Further, we overexpressed the homologous gene of SOAR1 in rice, OsSOAR1, and showed that transgenic plants overexpressing OsSOAR1 enhanced salt tolerance at seedling growth stage. Five salt- and other abiotic stress-induced SOAR1-like PPRs were also identified. These data showed that the SOAR1-like PPR proteins are positively involved in plant response to salt stress and may be used for crop improvement in rice under salinity conditions through transgenic manipulation.

High Expression of PARP1 in Tumor and Stroma Cells Predicts Different Prognosis and Platinum Resistance in Patients With Advanced Epithelial Ovarian Cancer.

Objective: This study aimed to explore the roles of PARP1 mRNA and protein expression in platinum resistance and prognosis of EOC patients, and reveal the different roles of PARP1 protein in epithelial tumor and stroma cells. Methods: The PARP1 mRNA expression of the EOC tissues was examined by RT-qPCR. The impacts of PARP1 expression on prognosis were measured by Kaplan-Meier and Cox regression. Receiver operating characteristic (ROC) curve analysis was employed for calculating the diagnostic value of PARP1 on platinum resistance. The microarray of formalin-fixed, paraffin-embedded (FFPE) tissues was processed for multiplex immunofluorescence to detect the protein levels of PARP1 and cytokeratin (CK). Results: The PARP1mRNA expression of EOC patients was higher in the platinum-resistant group compared with the sensitive group (P<0.01). Kaplan-Meier analysis demonstrated that high PARP1 mRNA expression was associated with poor survival of EOC patients. In Cox regression analyses, high PARP1 mRNA expression independently predicted poor prognosis (P=0.001, HR=2.076, 95%CI=1.373-3.140). The area under the ROC curve of PARP1 mRNA for predicting the platinum resistance in EOC patients was 0.649, with a sensitivity of 0.607 and specificity of 0.668. Furthermore, the protein expression of PARP1 was higher in the platinum-resistant group than in the sensitive group (P<0.01) and associated with a worse prognosis. Additionally, according to CK labeling, we observed that enhanced expression of PARP1 in the CK+ region was associated with platinum resistance and lower survival, but in CK- region, it predicted a good prognosis and platinum sensitivity. Conclusion: PARP1 may be a potential biomarker to predict platinum resistance and prognosis for EOC patients, exerting different roles on epithelial tumor and stromal cells.

Inheritance and breeding of japonica rice with good eating quality in Jiangsu province.

In order to develop a variety of japonica rice with good eating quality suitable for planting in Jiangsu Province, the genetic basis of high quality, disease resistance and high yield japonica rice varieties in Jiangsu Province was systematically studied. The relationship among different rice qualities of cooking, nutrition, and eating was studied by association analysis. It was clear that amylose content was the key factor affecting eating quality. The semi waxy rice with amylose content of 10%~14% has bright surface, soft texture, and elasticity, combining the softness of glutinous rice and the elasticity of japonica rice. The cold rice is not hard, and the taste is excellent. It meets the taste requirements of people in Yangtze River Delta region who like to eat soft fragrant japonica rice. The semi waxy japonica rice variety "Kantou 194" with a low expression of amylose content gene Wx mp and an amylose content of about 10% was selected as the core germplasm for improving eating quality. Pyramiding breeding of japonica rice variety with good eating quality, disease resistance and high yield was carried out by examining the development of Wx mp gene molecular markers and the use of closely linked molecular markers with disease resistance and high yield genes. A series of new japonica rice varieties with good taste such as Nanjing 46, Nanjing 5055, Nanjing 9108, and Nanjing 5718, suitable for different rice areas of Jiangsu Province, have been bred and approved by Jiangsu Provincial Variety Approval Committee. The layout of japonica rice varieties with good taste covering different rice areas in Jiangsu Province has been formed. These varieties have been planted with an accumulated area of more than 5.3 million hectares, which has effectively promoted the development of high quality rice industry in Jiangsu Province and its surrounding areas, and made important contributions to the structural adjustment of the supply side of rice industry, improving quality and efficiency, and ensuring food security.

The Arabidopsis kinase-associated protein phosphatase KAPP, interacting with protein kinases SnRK2.2/2.3/2.6, negatively regulates abscisic acid signaling.

KEY MESSAGE: The kinase-associated protein phosphatase, KAPP, is negatively involved in abscisic acid (ABA) signaling. KAPP interacts physically with SnRK2.2, SnRK2.3 and SnRK2.6, and functionally acts upstream of SnRK2.2 and SnRK2.3. The kinase-associated protein phosphatase (KAPP) has been reported to be involved in the regulation of many developmental and signaling events, but it remains unknown whether KAPP is involved in ABA signaling. Here, we report that KAPP is negatively involved in ABA-mediated seed germination and early seedling growth in Arabidopsis thaliana. The two loss-of-function mutants of KAPP, kapp-1 and kapp-2, exhibit increased ABA sensitivity in ABA-induced seed germination inhibition and post-germination growth arrest. The three closely-related protein kinase, (SNF1)-related protein kinase SnRK2.2, SnRK2.3 and SnRK2.6, which play critical roles in ABA signaling, interact and co-localize with KAPP. Genetic evidence showed that the ABA-hypersensitive phenotypes caused by KAPP mutation were suppressed by the double mutation of SnRK2.2 and SnRK2.3, indicating that KAPP functions upstream of SnRK2.2 and SnRK2.3 in ABA signaling. RNA-sequencing analysis revealed that KAPP mutation affects expression of multiple ABA-responsive genes. These results demonstrated that KAPP is negatively involved in plant response to ABA, which help to understand the complicated ABA signaling mechanism.

Mechanisms and effective control of physiological browning phenomena in plant cell cultures.

Browning phenomena are ubiquitous in plant cell cultures that severely hamper scientific research and widespread application of plant cell cultures. Up to now, this problem still has not been well controlled due to the unclear browning mechanisms in plant cell cultures. In this paper, the mechanisms were investigated using two typical materials with severe browning phenomena, Taxus chinensis and Glycyrrhiza inflata cells. Our results illustrated that the browning is attributed to a physiological enzymatic reaction, and phenolic biosynthesis regulated by sugar plays a decisive role in the browning. Furthermore, to confirm the specific compounds which participate in the enzymatic browning reaction, transcriptional profile and metabolites of T. chinensis cells, and UV scanning and high-performance liquid chromatography-mass spectrometry (HPLC-MS) profile of the browning compounds extracted from the brown-turned medium were analyzed, flavonoids derived from phenylpropanoid pathway were found to be the main compounds, and myricetin and quercetin were deduced to be the main substrates of the browning reaction. Inhibition of flavonoid biosynthesis can prevent the browning occurrence, and the browning is effectively controlled via blocking flavonoid biosynthesis by gibberellic acid (GA3 ) as an inhibitor, which further confirms that flavonoids mainly contribute to the browning. On the basis above, a model elucidating enzymatic browning mechanisms in plant cell cultures was put forward, and effective control approaches were presented.

Characterisation of water-soluble proanthocyanidins of Pyracantha fortuneana fruit and their improvement in cell bioavailable antioxidant activity of quercetin.

Proanthocyanidins (PCs) with poor bioavailability were argued for their health benefits. In this study, water-soluble polymeric polyphenolic PCs fractions from Pyracanthafortuneana fruit were used to investigate whether the presence of PCs is correlated with the increased cell antioxidant activities (CAA) of quercetin (Q). The results indicated that the most decrement in the values of EC50, which Q inhibited peroxyl radical-induced DCFH oxidation effective in the HepG2 cells, was observed to be 2.91 (vs. control 5.97) in the present of the fraction with 15.8 of the average degree of polymerisation of PCs (ADP). Also, the order of efficacy was the same with the ADP of PCs. Further, this effect is associated with the improvement of the solubility and stability of Q after the addition of the PCs. Our current study suggests that the additive effects of PCs on small molecular polyphenols may be responsible for their antioxidant benefits in vivo.

[Study on alkaloids of Corydalis ochotensis and their antitumor bioactivity].

OBJECTIVE: To investigate the chemical constituents of Corydalis ochotensis and their antitumor bioactivity. METHODS: The compounds were isolated by silica gel column chromatography and recrystallization. Their structures were identified by spectroscopic analysis (NMR) and physicochemical properties. Their cytotoxic activity was studied by MTT. RESULTS: Six compounds were elucidated as protopine (1), ochotensimine (2), fumariline (3), sanguinarine (4), tetrahydroberberine (5) and berberine (6). Compound 1 had excellent inhibitory activity on HepG2, SW480 and A549 cells, and compound 4 had excellent inhibitory activity on Hep2, HepG2, SW480 and A549 cells. CONCLUSION: Compounds 3, 4 and 5 are isolated from this plant for the first time; In the MTT antitumor experiments,compounds 1 and 4 show an antitumor activity.

Correlation analysis of the taxane core functional group modification, enzyme expression, and metabolite accumulation profiles under methyl jasmonate treatment.

Metabolomic and transcriptomic profiling data were obtained and integrated to elucidate the crucial network controls on taxol and its precursor biosynthesis during the taxane core functionalization within methyl jasmonate (MJ)-induced Taxus chinensis cells. Twelve metabolites were identified using liquid chromatography-electrospray ionization-mass spectrometry. These metabolites contain taxol (paclitaxel), baccatin III (B-III) and its analogs, a group structurally bearing multiple free hydroxyls (TAX), and another group of multiple acyl taxanes (MAT), including taxuyunnanine C (TC) and its analogs. The metabolomic profile showed a higher increase in TAX than in MAT. Particularly, the ratio of B-III and taxol to the total taxane content increased more significantly in TAX than in MAT. The MAT proportion did not significantly change, although they are predominant components in cell cultures compared with TAX. Quantitative real-time polymerase chain reaction (qRT-RCR) was used to determine the transcription level of 20 genes, among which 11 were reported responsible for taxol biosynthesis and 9 were obtained from our previous transcriptomic data. The total expression levels of hydroxylase after 24 h and 6 days were higher than those of acylase. The principal component analysis (PCA) results validated the metabolomic analysis data, indicating that hydroxylation was more crucial than acylation for controlling the flux toward TAX biosynthesis. Furthermore, the PCA contribution comparison showed that two undefined genes of OHX1 and ACX3 might have good potential in TAX upregulation and MAT downregulation. To the best of our knowledge, this study provides the first experimental evidence on the contribution of total hydroxylation to taxane biosynthesis.

Two novel dammarane-type compounds from the leaves and stems of Panax quinquefolium L.

Two new dammarane-type compounds were isolated from the leaves and stems of Panax quinquefolium L. The new compounds were named as pseudo-ginsenoside RT6 (1) and pseudoginsengenin R1 (2). The structures of the new compounds were elucidated by the combined analysis of NMR and HR-ESI-MS as (20S,24R)-6-O-ß-d-glucopyranosyl-dammar-3-one-20,24-epoxy-6α,12ß,25-triol (1) and (20S,24R)-dammar-3-one-20,24-epoxy-6α,12ß,25-triol (2).

Transcriptional profile of Taxus chinensis cells in response to methyl jasmonate.

BACKGROUND: Methyl jasmonate (MeJA) has been successfully used as an effective elicitor to enhance production of taxol and other taxanes in cultured Taxus cells. However the mechanism of MeJA-mediated taxane biosynthesis remains unclear. Genomic information for species in the genus Taxus is currently unavailable. Therefore, information about the transcriptome of Taxus cells and specifically, description of changes in gene expression in response to MeJA, is needed for the better exploration of the biological mechanisms of MeJA-mediated taxane biosynthesis. RESULTS: In this research, the transcriptome profiles of T. chinensis cells at 16 hours (T16) after MeJA treatment and of mock-treated cells (T0) were analyzed by "RNA-seq" to investigate the transcriptional alterations of Taxus cell in response to MeJA elicitation. More than 58 million reads (200 bp in length) of cDNA from both samples were generated, and 46,581 unigenes were found. There were 13,469 genes found to be expressed differentially between the two timepoints, including all of the known jasmonate (JA) biosynthesis/JA signaling pathway genes and taxol-related genes. The qRT-PCR results showed that the expression profiles of 12 randomly selected DEGs and 10 taxol biosynthesis genes were found to be consistent with the RNA-Seq data. MeJA appeared to stimulate a large number of genes involved in several relevant functional categories, such as plant hormone biosynthesis and phenylpropanoid biosynthesis. Additionally, many genes encoding transcription factors were shown to respond to MeJA elicitation. CONCLUSIONS: The results of a transcriptome analysis suggest that exogenous application of MeJA could induce JA biosynthesis/JA signaling pathway/defence responses, activate a series of transcription factors, as well as increase expression of genes in the terpenoid biosynthesis pathway responsible for taxol synthesis. This comprehensive description of gene expression information could greatly facilitate our understanding of the molecular mechanisms of MeJA-mediated taxane biosynthesis in Taxus cells.

[Exogenous Nkx2-5 gene expression induces the expression of cardiac markers during P19 cell differentiation in vitro].

OBJECTIVE: To investigate the role of homeobox gene Nkx2-5 in cardiac myogenesis. METHODS: Two P19 cell lines, namely cells transfected with exogenous expression of Nkx2-5 gene and non-transfected cells, were cultured in suspension for 4 days to induce cell aggregation, and the cell aggregates were transferred to the Petri dish for further adherent culture. On days 4, 8, 12 and 16 of adherent culture, the expressions of α-sarcomeric actin (α-SA) and cardiac troponin T (cTnT) protein were detected by immunocytochemistry, and the mRNA expressions of GATA-4, α-myosin heavy chain (α-MHC) and atrial natriuretic factor (ANF) genes by RT-PCR. RESULTS: In the transfected cells, α-SA and cTnT protein expressions were detected on days 8, 12 and 16 of adhere culture, and their expressions increased gradually with time. α-SA and cTnT expression was significantly higher on day 16 than on day 8 of culture (P<0.01). RT-PCR analysis of the transfected cell showed the presence of GATA-4 expression on day 4 of adherent culture, and the expression increased on days 8 and 12 but decreased on day 16. ANF and α-MHC expressions were found on days 8, 12, and 16, increasing gradually over time and showing significant differences from those on day 4 (P<0.05 or P<0.01). The expression of α-MHC was significantly higher on days 12 and 16 than on day 8 (P<0.05 or P<0.01), and ANF expression was significantly higher on day 16 than on days 8 and 12 (P<0.01). The non-transfected cells were negative for the expressions of all these genes. CONCLUSION: Exogenous expression of Nkx2-5 gene can induce P19 cells to express cardiac markers in vitro.

Efficient extraction of RNA and analysis of gene expression in a long-term Taxus cell culture using real-time RT-PCR.

A simple, quick and efficient method for isolating total RNA from heavy browning cells was developed by adding polyvinylpyrrolidone, mercaptoethanol and 3 M NaAc during the process of the Trizol (a kind of a widely used RNA extraction buffer) method. High-quality total RNA was isolated and synthesized to cDNA. Transcript levels of four paclitaxel biosynthetic pathway genes: dxr, hmgr, ggpps and dbat were assayed by real-time RT-PCR. The results demonstrated that the transcript levels of these genes experienced a coincident descent in the past three years as well as a decreasing paclitaxel productivity. According to these results, the possible reason for the descending paclitaxel productivity during long-term Taxus media cv. Hicksii cell culture maybe due to a decreasing transcripts level of mass genes in close with a gross secondary metabolite level. Gene manipulation emphasized only on key enzyme genes in the paclitaxel biosynthesis pathway may not hamper the somaclonal variation trend of Taxus media cv. Hicksii cell culture.

[Study on excretion of pseudo-ginsenoside GQ].

OBJECTIVE: To determine the pseudo-ginsenoside GQ (PGQ) in rat bile, feces and urine, and to study on the excretion of pseudo-ginsenoside GQ. METHOD: Reverse phase high-performance liquid chromatography (RP-HPLC) method with an evaporative light-scattering detector (ELSD) was performed on Diamonsil C18 column (4.6 mm x 250 mm, 5 microm), and the mobile phase was consisted of methanol-water (24: 7) with flow rate of 1.0 mL x min(-1). ELSD parameters were set as follows: nitrogen gas pressure 3.0 bar, drift tube temperature 50 degrees C. RESULT: The method fulfilled all the standard requirements of precision, accuracy and linearity. The main way of excretion of PGQ in rat administrated through sublingual vein was at the bile. The bile excretion ratio of PGQ was 41.60%, and feces excretion ratio was 9.97%. Only trace amount of PGQ was excreted in urine. CONCLUSION: Almost all unchanged PGQ was excreted in bile, feces and urine.

[LC-ESI-MS metabolic profiling analysis of taxanes from the extracts of Taxus chinensis cell cultures].

AIM: To develop a rapid analytical method for small amount biological samples of taxanes by using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS) in small amount biological samples. METHODS: A solution containing five given taxane constituents and the extract from cell cultures of Taxus chinensis were analysed separately. According to the performance of the given taxanes in ESI-MS/MS, run parameters of the mass spectrometer were optimized. Positive and negative electrospray modes were employed to simultaneously scan the cell cultures sample, and the full ion chromatogram and the molecular weight of individual peak were obtained. The qualitative analysis of taxanes was achieved by comparison of the retention time and molecular weight with those of the reference substances or was based on the interpretation of the MS/MS spectra of the analytes and the knowledge of the concerning genetic backgrounds of taxanes published in literatures. RESULTS: The taxanes with several acetyl substituents tended to produce ammonium adduct ions peak, while multi-hydroxy taxanes were subject to give protonized molecular ion peaks in positive ion ESI-MS. Thirteen taxanes in cell samples were assigned. Eight compounds of them were identified to be 1 -acetyl-5, 7, 10-deacetyl-baccatin I (DAB-I, 1) , baccatin III (B-III, 3), baccatin VI (B-VI, 8), taxol (9), yunnanxane (10 ), taxuyunnanine C (Tc, 11), sinenxane B (12), sinenxane C (13), separately. For the other five constituents, character of taxane and the number of substituents were deduced. CONCLUSION: The results confirm the feasibility of characterizing taxanes in biological samples by LC-ESI-MS analysis. The analytical methodology provided a rapid, conventional and reliable tool to study metabolic profiling of taxanes for structural elucidation in taxol biosynthesis.

[Effects of fosmidomycin and lovastatin treatment on taxol biosynthesis in suspension culture cells of Taxus chinensis].

There is a dichotomy in the biosynthetic pathway of terpenoid precursor isopentenyl diphosphate (IPP) in higher plant. One is the classical mevalonate pathway in cytosol, and the other is non-mevalonate pathway in plastid. To know the origin of the taxane ring system of taxol in suspension culture of Taxus chinensis, lovastatin and fosmidomycin were used to block the 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and 1-deoxy-D-xylulose-5-phosphate reducto-isomerase (DXR) in the mevalonate and non-mevalonate branch respectively of the terpenoid biosynthetic pathway. Methyl jasmonate (MJ) was used to improve the biosynthesis of taxol. Taxol content was determined by HPLC, the transcriptional expression of genes encoding DXR and HMGR were investigated by real time PCR. Taxol production was lowered by about 2/5 and 1/5 by fosmidomycin (200 mmol/L) and fosmidomycin (200 mmol/L)+MJ (100 mmol/L) treatment respectively, and was lowered by about 1/6 and 1/10 by lovastatin (1 mmol/L) and lovastatin (1 mmol/L) + MJ (100 mmol/L) respectively, which means that both mevalonate and non-mevalonate pathway contribute to taxol biosynthesis, and the latter is the main source of IPP. Inhibitors lovastatin and fosmidomycin both promoted the transcriptional expression of hmgr and dxr, which indicated a metabolic cross talk between cytosolic and plastidial pathways of taxol biosynthesis.