Association of modic changes and postoperative surgical site infection after posterior lumbar spinal fusion.

PURPOSE: Postoperative surgical site infection is one of the most serious complications following spine surgery. Previous studies have reported Modic changes (MC) represent a subclinical infection. This study aims to investigate the relation between Modic changes and surgical site infection after posterior lumbar fusion surgery. METHODS: We retrospectively reviewed the records of 424 patients who received posterior lumbar fusion. Preoperative clinical and radiological parameters were recorded. Primary outcome was the rate of postoperative surgical site infection. Covariates included age, body mass index (BMI), sex, hypertension, diabetes mellitus, chronic heart failure, Pfirrmann classification, fused levels, and operation duration. The presence of Modic changes was used as an exposition variable, and adjusted for other risk factors in multivariate analyses. RESULTS: Of the 424 patients, 30 (7%) developed an acute surgical site infection. Infection had no relation to age, sex, BMI, and comorbidities. There were 212 (50%) patients with MC, and 23 (10.8%) had a surgical site infection, compared to 212 (50%) patients without MC in which there were 7 (3.3%) surgical site infections. MC was associated with surgical site infection in univariate analysis (odds ratio [OR] = 3.56, 95% confidence interval [CI]: 1.49-8.50, p = 0.004) and multivariate logistic regression analysis (OR = 3.05, 95% CI: 1.26-7.37, p = 0.013). There was statistically significant between specific type (p = 0.035) and grade of MCs (p = 0.0187) and SSI. CONCLUSIONS: MCs may be a potential risk factor for SSI following posterior lumbar spinal intervertebral fusion. Type I and grade C MCs showed a higher infection rate compared with other MC types and grades.

A Rapid Alkalinization Factor-like Peptide EaF82 Impairs Tapetum Degeneration during Pollen Development through Induced ATP Deficiency.

In plants, the timely degeneration of tapetal cells is essential for providing nutrients and other substances to support pollen development. Rapid alkalinization factors (RALFs) are small, cysteine-rich peptides known to be involved in various aspects of plant development and growth, as well as defense against biotic and abiotic stresses. However, the functions of most of them remain unknown, while no RALF has been reported to involve tapetum degeneration. In this study, we demonstrated that a novel cysteine-rich peptide, EaF82, isolated from shy-flowering 'Golden Pothos' (Epipremnum aureum) plants, is a RALF-like peptide and displays alkalinizing activity. Its heterologous expression in Arabidopsis delayed tapetum degeneration and reduced pollen production and seed yields. RNAseq, RT-qPCR, and biochemical analyses showed that overexpression of EaF82 downregulated a group of genes involved in pH changes, cell wall modifications, tapetum degeneration, and pollen maturation, as well as seven endogenous Arabidopsis RALF genes, and decreased proteasome activity and ATP levels. Yeast two-hybrid screening identified AKIN10, a subunit of energy-sensing SnRK1 kinase, as its interacting partner. Our study reveals a possible regulatory role for RALF peptide in tapetum degeneration and suggests that EaF82 action may be mediated through AKIN10 leading to the alteration of transcriptome and energy metabolism, thereby causing ATP deficiency and impairing pollen development.

Association between immediate postoperative hypoalbuminemia and surgical site infection after posterior lumbar fusion surgery.

PURPOSE: In this study, we intended to investigate the association between immediate postoperative hypoalbuminemia and surgical site infection (SSI), and determine a threshold value for postoperative hypoalbuminemia that can assist in risk stratification in patients after posterior lumbar fusion surgery. METHODS: From January 2017 to December 2021, 466 consecutive patients who underwent posterior lumbar fusion surgery were selected to analyze the relationship between immediate postoperative hypoalbuminemia and SSI. Multivariate logistic regression analysis was performed to identify the independent risk factors of SSI and postoperative hypoalbuminemia. Receiver Operating Characteristic (ROC) analysis was used to determine the optimal value for postoperative hypoalbuminemia, and subsequent grouping was based on the identified threshold. RESULTS: Of the total 466 patients, 25 patients (5.4%) developed SSI after surgery, and lower postoperative albumin (OR: 0.716, 95% CI: 0.611-0.840, p < 0.001) was independently associated with SSI. ROC analysis showed that the cutoff value of postoperative hypoalbuminemia was 32 g/L with a sensitivity of 0.760, specificity of 0.844, and a Youden index of 0.604. Postoperative SSI was more common in patients with postoperative hypoalbuminemia than in those without (21.6% vs. 1.6%, p < 0.001). Age, gender and operative duration were found to be independent predictors of postoperative hypoalbuminemia. CONCLUSIONS: This study showed that immediate postoperative hypoalbuminemia was an independent risk factor for the development of SSI in patients who underwent posterior lumbar fusion. Even in patients with a normal preoperative serum albumin level, there was an increased risk of SSI when the postoperative albumin within 24 h was < 32 g/L.

Asialo-rhuEPO as a Potential Neuroprotectant for Ischemic Stroke Treatment.

Neuroprotective drugs to protect the brain against cerebral ischemia and reperfusion (I/R) injury are urgently needed. Mammalian cell-produced recombinant human erythropoietin (rhuEPOM) has been demonstrated to have excellent neuroprotective functions in preclinical studies, but its neuroprotective properties could not be consistently translated in clinical trials. The clinical failure of rhuEPOM was thought to be mainly due to its erythropoietic activity-associated side effects. To exploit its tissue-protective property, various EPO derivatives with tissue-protective function only have been developed. Among them, asialo-rhuEPO, lacking terminal sialic acid residues, was shown to be neuroprotective but non-erythropoietic. Asialo-rhuEPO can be prepared by enzymatic removal of sialic acid residues from rhuEPOM (asialo-rhuEPOE) or by expressing human EPO gene in glycoengineered transgenic plants (asialo-rhuEPOP). Both types of asialo-rhuEPO, like rhuEPOM, displayed excellent neuroprotective effects by regulating multiple cellular pathways in cerebral I/R animal models. In this review, we describe the structure and properties of EPO and asialo-rhuEPO, summarize the progress on neuroprotective studies of asialo-rhuEPO and rhuEPOM, discuss potential reasons for the clinical failure of rhuEPOM with acute ischemic stroke patients, and advocate future studies needed to develop asialo-rhuEPO as a multimodal neuroprotectant for ischemic stroke treatment.

A plant-based mutant huntingtin model-driven discovery of impaired expression of GTPCH and DHFR.

Pathophysiology associated with Huntington's disease (HD) has been studied extensively in various cell and animal models since the 1993 discovery of the mutant huntingtin (mHtt) with abnormally expanded polyglutamine (polyQ) tracts as the causative factor. However, the sequence of early pathophysiological events leading to HD still remains elusive. To gain new insights into the early polyQ-induced pathogenic events, we expressed Htt exon1 (Httex1) with a normal (21), or an extended (42 or 63) number of polyQ in tobacco plants. Here, we show that transgenic plants accumulated Httex1 proteins with corresponding polyQ tracts, and mHttex1 induced protein aggregation and affected plant growth, especially root and root hair development, in a polyQ length-dependent manner. Quantitative proteomic analysis of young roots from severely affected Httex1Q63 and unaffected Httex1Q21 plants showed that the most reduced protein by polyQ63 is a GTP cyclohydrolase I (GTPCH) along with many of its related one-carbon (C1) metabolic pathway enzymes. GTPCH is a key enzyme involved in folate biosynthesis in plants and tetrahydrobiopterin (BH4) biosynthesis in mammals. Validating studies in 4-week-old R6/2 HD mice expressing a mHttex1 showed reduced levels of GTPCH and dihydrofolate reductase (DHFR, a key folate utilization/alternate BH4 biosynthesis enzyme), and impaired C1 and BH4 metabolism. Our findings from mHttex1 plants and mice reveal impaired expressions of GTPCH and DHFR and may contribute to a better understanding of mHtt-altered C1 and BH4 metabolism, and their roles in the pathogenesis of HD.

Influencing Factors of Health Technology Assessment to Orphan Drugs: Empirical Evidence in England, Scotland, Canada, and Australia.

This study summarizes the intrinsic criteria for the recommendation of orphan drugs in England, Scotland, Canada, and Australia with the aim of understanding the rationale for the variability in decision-making and to provide a reference for the establishment of criteria in the process of access to health insurance for orphan drugs in different countries and the construction of national uniform criteria. A comparative analysis of 60 health technology assessment (HTA) guidelines of 15 drug-indication pairs appraised by four countries (England, Scotland, Canada, and Australia) from 2017 to 2018 was done, including an in-depth analysis of a case study. Agreement levels were measured using kappa scores. Associations were explored through correspondence analysis. The four countries possess some homogeneity in the assessment, but each has its own preferences. Poor agreement exists between England, Scotland, and Canada (-0.41 < kappa score < 0.192). In the correspondence analysis, England placed more emphasis on treatment methods in terms of control type when making recommendations. Canada and Scotland focused more on trial type with Canada placing more emphasis on phase III and open-label trials and on cost-utility analysis, while Australia was less studied in terms of economic models. Different countries have different goals when establishing HTA decisions for orphan drugs due to their different degrees of orphan drug coverage. Different countries should not only combine their unique values of clinical benefit and cost-effectiveness in the assessment of orphan drugs but also give different weights during the HTA process, after considering account the development of the country itself.

Effect of pre-oxidation process on V2O5/AC catalyst for the selective catalytic reduction of NOx with NH3.

Activated coke-based catalysts have attracted extensive attention in denitration by selective catalytic reduction by NH3 (NH3-SCR), due to their excellent catalytic performance at low temperature. In the paper, the V2O5/AC catalyst was prepared by the impregnation method to investigate the effect of pre-oxidation process on its NH3-SCR activity. Activity test results show that the V2O5/AC catalyst with 4-h pre-oxidation exhibits the best NOx removal efficiency, which reaches the NOx conversion is over 75% in the range of 200-240 °C and exhibits an excellent resistance to SO2 and H2O. Characterization results demonstrate that the V4+ was oxidized by oxygen molecule during pre-oxidation process, which contributes to the formation of V5+ ions and surface-active oxygen species. The surface-active oxygen species are conducive to promoting the "fast SCR" reaction; thus, the pre-oxidized process can contribute to the superior NH3-SCR performance for V2O5/AC catalyst at low temperature.

A Novel Plant-Produced Asialo-rhuEPO Protects Brain from Ischemic Damage Without Erythropoietic Action.

Mammalian cell-produced recombinant human erythropoietin (rhuEPOM) has been shown to be a multimodal neuroprotectant targeting an array of key pathological mechanisms in experimental stroke models. However, the rhuEPOM clinical trials were terminated due to increased risk of thrombosis, largely ascribed to its erythropoietic function. We recently took advantage of a plant-based expression system lacking sialylation capacity to produce asialo-rhuEPOP, a rhuEPO derivative without sialic acid residues. In the present study, we proved that asialo-rhuEPOP is non-erythropoietic by repeated intravenous injection (44 µg/kg bw) in mice showing no increase in hemoglobin levels and red blood cell counts, and confirmed that it is non-immunogenic by measuring humoral response after immunizing the mice. We demonstrate that it is neuroprotective in a cerebral ischemia and reperfusion (I/R) mouse model, exhibiting ~ 50% reduction in cerebral infarct volume and edema, and significant improvement in neurological deficits and histopathological outcome. Our studies further revealed that asialo-rhuEPOP, like rhuEPOM, displays pleiotropic neuroprotective effects, including restoring I/R-interrupted mitochondrial fission and fusion proteins, preventing I/R injury-induced increase in mitophagy and autophagy markers, and inhibiting apoptosis to benefit nerve cell survival. Most importantly, asialo-rhuEPOP lacking erythropoietic activity and immunogenicity holds great translational potential as a multimodal neuroprotectant for stroke treatment.

Rethinking the necessity of low glucose intervention for cerebral ischemia/reperfusion injury.

Glucose is the essential and almost exclusive metabolic fuel for the brain. Ischemic stroke caused by a blockage in one or more cerebral arteries quickly leads to a lack of regional cerebral blood supply resulting in severe glucose deprivation with subsequent induction of cellular homeostasis disturbance and eventual neuronal death. To make up ischemia-mediated adenosine 5'-triphosphate depletion, glucose in the ischemic penumbra area rapidly enters anaerobic metabolism to produce glycolytic adenosine 5'-triphosphate for cell survival. It appears that an increase in glucose in the ischemic brain would exert favorable effects. This notion is supported by in vitro studies, but generally denied by most in vivo studies. Clinical studies to manage increased blood glucose levels after stroke also failed to show any benefits or even brought out harmful effects while elevated admission blood glucose concentrations frequently correlated with poor outcomes. Surprisingly, strict glycaemic control in clinical practice also failed to yield any beneficial outcome. These controversial results from glucose management studies during the past three decades remain a challenging question of whether glucose intervention is needed for ischemic stroke care. This review provides a brief overview of the roles of cerebral glucose under normal and ischemic conditions and the results of managing glucose levels in non-diabetic patients. Moreover, the relationship between blood glucose and cerebral glucose during the ischemia/reperfusion processes and the potential benefits of low glucose supplements for non-diabetic patients are discussed.

Transformation of Long-Lived Albino Epipremnum aureum 'Golden Pothos' and Restoring Chloroplast Development.

Chloroplasts are organelles responsible for chlorophyll biosynthesis, photosynthesis, and biosynthesis of many metabolites, which are one of key targets for crop improvement. Elucidating and engineering genes involved in chloroplast development are important approaches for studying chloroplast functions as well as developing new crops. In this study, we report a long-lived albino mutant derived from a popular ornamental plant Epipremnum aureum 'Golden Pothos' which could be used as a model for analyzing the function of genes involved in chloroplast development and generating colorful plants. Albino mutant plants were isolated from regenerated populations of variegated 'Golden Pothos' whose albino phenotype was previously found to be due to impaired expression of EaZIP, encoding Mg-protoporphyrin IX monomethyl ester cyclase. Using petioles of the mutant plants as explants with a traceable sGFP gene, an efficient transformation system was developed. Expressing Arabidopsis CHL27 (a homolog of EaZIP) but not EaZIP in albino plants restored green color and chloroplast development. Interestingly, in addition to the occurrence of plants with solid green color, plants with variegated leaves and pale-yellow leaves were also obtained in the regenerated populations. Nevertheless, our study shows that these long-lived albino plants along with the established efficient transformation system could be used for creating colorful ornamental plants. This system could also potentially be used for investigating physiological processes associated with chlorophyll levels and chloroplast development as well as certain biological activities, which are difficult to achieve using green plants.

Quantitative Proteomics Reveals the Beneficial Effects of Low Glucose on Neuronal Cell Survival in an in vitro Ischemic Penumbral Model.

Understanding proteomic changes in the ischemic penumbra are crucial to rescue those salvageable cells and reduce the damage of an ischemic stroke. Since the penumbra region is dynamic with heterogeneous cells/tissues, tissue sampling from animal models of stroke for the molecular study is a challenge. In this study, cultured hippocampal HT22 cells under hypoxia treatment for 17.5 h with 0.69 mM low glucose (H+LG) could mimic ischemic penumbral cells since they had much higher cell viability and viable cell number compared to hypoxia without glucose (H-G) treatment. To validate established cell-based ischemic penumbral model and understand the beneficial effects of low glucose (LG), quantitative proteomics analysis was performed on H+LG, H-G, and normoxia with normal 22 mM glucose (N+G) treated cells. We identified 427 differentially abundant proteins (DAPs) between H-G and N+G and further identified 105 DAPs between H+LG and H-G. Analysis of 105 DAPs revealed that LG promotes cell survival by activating HIF1α to enhance glycolysis; preventing the dysregulations of extracellular matrix remodeling, cell cycle and division, and antioxidant and detoxification; as well as attenuating inflammatory reaction response, protein synthesis and neurotransmission activity. Our results demonstrated that this established cell-based system could mimic penumbral conditions and can be used for molecular studies.

Glycoengineering tobacco plants to stably express recombinant human erythropoietin with different N-glycan profiles.

Plant-based expression system has many potential advantages to produce biopharmaceuticals, but plants cannot be directly used to express human glycoproteins because of their differences in glycosylation abilities from mammals. To exploit plant-based expression system for producing recombinant human erythropoietin (rhuEPO), we glycoengineered tobacco plants by stably introducing seven to eight mammalian genes including a target human EPO into tobacco in order to generate capacities for ß1,4-galactosylation, bisecting N-acetylglucosamine (GlcNAc) and sialylation. Wild type human ß1,4-galactosyltransferase gene (GalT) or a chimeric GalT gene (ST/GalT) was co-expressed to produce rhuEPO bearing ß1,4-galactose-extended N-glycan chains as well as compare their ß1,4-galactosylation efficiencies. Five mammalian genes encoding enzymes/transporter for sialic acid biosynthesis, transport and transfer were co-expressed to build sialylation capacity in plants. The human MGAT3 was co-expressed to produce N-glycan chains with bisecting GlcNAc. Our results demonstrated that the above transgenes were incorporated into tobacco genome and transcribed. ST/GalT was found to be more efficient than GalT for ß1,4-galactosylation. Furthermore, co-expressing MGAT3 generated N-glycans likely bearing bisected GlcNAc. However, our current efforts did not result in generating sialylation capacity. Created transgenic plants expressing EPO and ST/GalT could be used to produce rhuEPO with high proportion of ß1,4-galactose-extended N-glycan chains for tissue protective purposes.

Recombinant asialoerythropoetin protects HL-1 cardiomyocytes from injury via suppression of Mst1 activation.

BACKGROUND: Recombinant human erythropoietin (rhuEPO) and asialoerythropoietin (asialo-rhuEPO) are cardioprotective. However, the protective effects of rhuEPO could not be translated into clinical practice because of its hematopoiesis-associated side effects while non-erythropoietic asialo-rhuEPO is unavailable in large quantities for clinical studies. This study was designed to investigate the cardiomyocyte protective potential of plant-produced asialo-rhuEPO (asialo-rhuEPOP) against staurosporine (STS)-induced injury in HL-1 murine cardiomyocytes and identify cellular pathway(s) responsible for its cardioprotection. METHODS: HL-1 cardiomyocytes were simultaneously treated with STS and asialo-rhuEPOP. Cellular injury, apoptosis, and cell viabilities were measured by LDH assay, Hoechst staining and trypan blue exclusion method, respectively while western blotting was used to study its effects on apoptosis and autophagy hallmarks. RESULTS: Our results showed that 20 IU/ml asialo-rhuEPOP provided 39% protection to cardiomyocytes compared to STS-treated cells, which is 2-fold better than that of mammalian cell-produce rhuEPO (rhuEPOM). Asialo-rhuEPOP was found to suppress activation of proapoptotic kinase Mst1 (mammalian Sterile-20-like kinase 1) and FOXO3, leading to inhibition of apoptotic pathway and restoration of autophagy as indicated by the reduction of fragmented/condensed nuclei, altered ratios of Bax/Bcl2, p-Bad/Bad, cytosol/mitochondrial cyt c and caspase-3 activation, and the restored levels of autophagy markers Beclin1, p62 and LC3B-II. Additionally, Akt was found to be activated and FOXO3 was phosphorylated on Ser253, suggesting inhibition of FOXO3 transcriptional function. CONCLUSIONS: Asialo-rhuEPOP-mediated cardioprotection occurs through activation of PI3K/Akt pathway leading to suppression of Mst1 activation and promoting cardiomyocyte survival. GENERAL SIGNIFICANCE: Asialo-rhuEPOP could be used to modulate Mst1 activity elevated under numerous pathological states.

An Effective Way of Producing Fully Assembled Antibody in Transgenic Tobacco Plants by Linking Heavy and Light Chains via a Self-Cleaving 2A Peptide.

Therapeutic monoclonal antibodies (mAbs) have evolved into an important class of effective medicine in treatment of various diseases. Since the antibody molecule consists of two identical heavy chains (HC) and two light chains (LC), each chain encoded by two different genes, their expressions at similar levels are critical for efficient assembly of functional recombinant mAbs. Although the plant-based expression system has been tested to produce fully assembled recombinant mAbs, coordinately expressing HC and LC at similar levels in a transgenic plant remains a challenge. A sequence coding for a foot-and-mouth disease virus (FMDV) 2A peptide has been successfully used to link two or more genes, which enable the translated polyprotein to be "self-cleaved" into individual protein in various genetically modified organisms. In the present study, we exploited the usage of F2A in Ebola virus monoclonal antibody (EBOV mAb) production. We found that transgenic tobacco plants carrying a transcription unit containing HC and LC linked by 2A not only produced similar levels of HC and LC but also rendered a higher yield of fully assembled EBOV mAb compared to those expressing HC and LC in two independent transcription units. Purified EBOV mAb bound to an Ebola epitope peptide with apparent Kd -values of 90.13-149.2 nM, indicating its proper assembly and high affinity binding to Ebola epitope peptide. To our knowledge, this is the first report showing mAb production by overexpressing a single transcription unit consisting of HC, LC and 2A in stable transformed tobacco plants.

Plant-Produced Asialo-Erythropoietin Restores Pancreatic Beta-Cell Function by Suppressing Mammalian Sterile-20-like Kinase (MST1) and Caspase-3 Activation.

Pancreatic beta-cell death adversely contributes to the progression of both type I and II diabetes by undermining beta-cell mass and subsequently diminishing endogenous insulin production. Therapeutics to impede or even reverse the apoptosis and dysfunction of beta-cells are urgently needed. Asialo-rhuEPO, an enzymatically desialylated form of recombinant human erythropoietin (rhuEPO), has been shown to have cardioprotective and neuroprotective functions but with no adverse effects like that of sialylated rhuEPO. Heretofore, the anti-apoptotic effect of asialo-rhuEPO on pancreatic beta-cells has not been reported. In the current study, we investigated the cytoprotective properties of plant-produced asialo-rhuEPO (asialo-rhuEPOP) against staurosporine-induced cell death in the pancreatic beta-cell line RIN-m5F. Our results showed that 60 IU/ml asialo-rhuEPOP provided 41% cytoprotection while 60 IU/ml rhuEPO yielded no effect. Western blotting results showed that asialo-rhuEPOP treatment inhibited both MST1 and caspase-3 activation with the retention of PDX1 and insulin levels close to untreated control cells. Our study provides the first evidence indicating that asialo-rhuEPOP-mediated protection involves the reduction of MST1 activation, which is considered a key mediator of apoptotic signaling in beta-cells. Considering the many advantages its plant-based expression, asialo-rhuEPOP could be potentially developed as a novel and inexpensive agent to treat or prevent diabetes after further performing studies in cell-based and animal models of diabetes.

Overexpression of an EaZIP gene devoid of transit peptide sequence induced leaf variegation in tobacco.

Leaf variegation is an ornamental trait that is not only biologically but also economically important. In our previous study, a Mg-protoporphyrin IX monomethyl ester cyclase homologue, EaZIP (Epipremnum aureum leucine zipper) was found to be associated with leaf variegation in Epipremnum aureum (Linden & Andre) G.S. Bunting. The protein product of this nuclear-encoded gene is targeted back to chloroplast involving in chlorophyll biosynthesis. Based on a web-based homology analysis, the EaZIP was found to lack a chloroplast transit peptide (cTP) sequence. In the present study, we tested if overexpression of the EaZIP cDNA with or without the cTP sequence could affect leaf variegation. Transgenic tobacco plants overexpressing EaZIP genes with (EaZIPwcTP) and without (EaZIPwocTP) cTP sequence were generated. Many plant lines harboring EaZIPwocTP showed variegated leaves, while none of the plant lines with EaZIPwcTP produced such a phenotype. Molecular analysis of T0 plants and selfed T1 progeny, as well as observations of tagged marker GFP (green fluorescent protein) did not show any other difference in patterns of gene integrity and expression. Results from this study indicate that transgenic approach for expressing EaZIPwocTP could be a novel method of generating variegated plants even through the underlying mechanisms remain to be elucidated.

Accumulation of high OPDA level correlates with reduced ROS and elevated GSH benefiting white cell survival in variegated leaves.

Variegated 'Marble Queen' (Epipremnum aureum) plant has white (VMW) and green (VMG) sectors within the same leaf. The white sector cells containing undifferentiated chloroplasts are viable, but the underlying mechanism for their survival and whether these white cells would use any metabolites as signal molecules to communicate with the nucleus for maintaining their viability remain unclear. We analyzed and compared phytohormone levels with their precursors produced in chloroplasts between VMW and VMG, and further compared their transcriptomes to understand the consequences related to the observed elevated 12-oxo phytodienoic acid (OPDA), which was 9-fold higher in VMW than VMG. Transcriptomic study showed that a large group of OPDA-responsive genes (ORGs) were differentially expressed in VMW, including stress-related transcription factors and genes for reactive oxygen species (ROS) scavengers, DNA replication and repair, and protein chaperones. Induced expression of these ORGs could be verified in OPDA-treated green plants. Reduced level of ROS and higher levels of glutathione in VMW were further confirmed. Our results suggest that elevated OPDA or its related compounds are recruited by white cells as a signaling molecule(s) to up-regulate stress and scavenging activity related genes that leads to reduced ROS levels and provides survival advantages to the white cells.

Gibberellin deficiency is responsible for shy-flowering nature of Epipremnum aureum.

Epipremnum aureum is an extremely popular houseplant belonging to the Araceae family of angiosperms, but it does not flower either in the wild or under cultivation. We uncovered the potential causes of its shy-flowering nature by building the transcriptome using next-generation sequencing and identifying floral-related genes that are differentially expressed between vertical growth (VG, adult) and horizontal growth (HG, juvenile) plants. Transcripts of the gibberellin (GA) biosynthetic gene EaGA3ox1 and GA-responsive floral meristem identity gene EaLFY were absent in both VG and HG plants, suggesting that a deficiency of bioactive GAs may be responsible for its shy-flowering nature. This hypothesis is supported by undetectable or low levels of three bioactive GAs, and exogenous GA3 triggered flowering in both plants. Our study resolves the mystery why E. aureum fails to flower, and reveals the positive role of GAs in floral transition in perennials.

Nicotine biosynthesis is regulated by two more layers: Small and long non-protein-coding RNAs.

In recent years, many small RNAs and long non-protein-coding RNAs (lncRNAs) have been identified and characterized. They have been proved to play essential regulatory roles in gene expression in both primary and secondary metabolisms. In nature, many plants produce alkaloids. However, there are only few reports on the involvement of non-coding RNAs in alkaloid biosynthesis. Nicotine is major alkaloid in tobacco plants. Its biosynthesis and regulation in tobacco (Nicotiana tabacum) have been well studied; and major structural genes involved in the nicotine biosynthesis and transcriptional regulators related to its biosynthesis have been identified and characterized. In our recent studies, we identified a microRNA (nta-miRX27) and also a lncRNA (nta-eTMX27) as an endogenous target mimicry (eTM) in tobacco targeting the nicotine biosynthesis key gene QPT2 encoding quinolinate phosphoribosyltransferase (QPT) and thereby regulating the nicotine content. Their regulatory pattern leads us to conclude that nicotine biosynthesis is regulated by 2 more layers besides previously known mechanisms. Future study on the relationship between the non-coding RNAs and transcription factors in nicotine biosynthesis was discussed in this article.