Ethanol suppresses rice seed germination through inhibiting ROS signaling.

Ethanol is frequently used not only as priming but also as a solvent to dissolve hardly water-soluble phytohormones gibberellic acid (GA3) and abscisic acid (ABA) in seed germination. However, the molecular and physiological mechanisms of ethanol's impact on seed germination remain elusive. In this report, we investigated how ethanol affected reactive oxygen species (ROS) during rice seed germination. Ethanol at a concentration of 3.5% (v/v) inhibited 90% seed germination, which was almost reversed by H2O2. H2O2 contents in embryos were reduced by ethanol after 18 h imbibition. Antioxidant enzymes assays revealed that only superoxide dismutase (SOD) activities in seed embryos were lowered by ethanol, in line with the suppressed mRNA expression of SOD genes during imbibition. Additionally, compared to the mock condition, ethanol increased ABA contents but decreased GA (GA1 and GA3) in seed embryos, resulting in disharmonizing GA/ABA balance. Conceivably ethanol induced transcription of OsNCEDs, the key genes for ABA biosynthesis, and OsABA8ox3, a key gene for ABA catabolism. Furthermore, ethanol promoted ABA signaling by upregulating ABA receptor genes and ABA-responsive element (ABRE)-binding protein/ABRE-binding factors during imbibition. Overall, our results demonstrate that lowering of H2O2 levels due to suppressed SOD activities in rice germinating seed embryos is the decisive factor for ethanol-induced inhibition of seed germination, and GA/ABA balance and ABA signaling also play important roles in ethanol's inhibitory impact on seed germination.

Comparison of effectiveness and safety of high-power vs. conventional-power radiofrequency ablation for treatment of atrial fibrillation.

Aim: To compare high-power (HP) vs. conventional-power (CP) radiofrequency ablation for atrial fibrillation (AF). Methods: We retrospectively enrolled AF patients undergoing CP (30-40 W, 43 patients) or HP (50 W, 49 patients) radiofrequency ablation. Immediate pulmonary vein (PV) single-circle isolation, PV-ablation time, AF recurrence, AF recurrence-free survival, and complications were analyzed. Results: Diabetes was more common in the CP group than in the HP group (27.91% vs. 10.20%, P = 0.029). The left PV single-circle isolation rate (62.79% vs. 65.31%), right PV single-circle isolation rate (48.84% vs. 53.06%), and bilateral PV single-circle isolation rate (32.56% vs. 38.78%; all P > 0.05) did not differ between the groups. Single-circle ablation times for the left PVs (12.79 ± 3.39 vs. 22.94 ± 6.39 min), right PVs (12.18 ± 3.46 vs. 20.67 ± 5.44 min), and all PVs (25.85 ± 6.04 vs. 45.66 ± 11.11 min; all P < 0.001) were shorter in the HP group. Atrial fibrillation recurrence within 3 months (13.95% vs. 18.37%), at 3 months (11.63% vs. 8.16%), and at 6 months after ablation (18.60% vs. 12.24%; all P > 0.05) was similar in both groups. Atrial fibrillation recurrence-free survival did not differ between the groups (Kaplan-Meier analysis). Cardiac rupture and pericardial tamponade did not occur in any patient. Pops occurred in 2 and 0 patients in the HP and CP groups, respectively (4.08% vs. 0.00%, P = 0.533). Conclusion: High-power ablation improved operation time and efficiency without increasing complications.

Aggregation of Fe2O3 nanoparticle in the presence of organophosphate esters (OPEs).

Aggregation is a key process for determining the environmental behavior and impact of a nanoparticle (NP). Since organophosphate esters (OPEs), which are recognized as emerging contaminants, are distributed widely in the natural aquatic environment, they may contribute to interacting with NPs and ultimately influence their transport and fate. Here, we investigated two typical organophosphate esters OPEs on aggregation the Fe2O3 NP in aquatic environments. The results showed that both tri-ethylhexyl phosphate (TEHP) and tris (chloroisopropyl) phosphate (TCPP) improved the colloidal stability of Fe2O3 NP in artificial water and environmental matrices. TEHP exhibited an obvious effect than TCPP on the Zeta potential and aggregation rates of Fe2O3 NP in artificial water. In the presence of electrolyte, 10 mg/L TCPP and TEHP increased the critical coagulation concentration (CCC) by 3.6 times and 17.4 times, respectively. Compared with pore-water, the aggregation rates of Fe2O3 NP in river water were slightly higher than those in pore-water, which can be attributed to the higher DOC in pore-water. We suggested that the high hydrophobicity and molecular weight of OPEs were considered important factors against the aggregation of Fe2O3 NP in water. Greater surface charge and steric hindrance originating from TCPP and TEHP dominated the colloidal stability of Fe2O3 NP.

EROSION III: A Multicenter RCT of OCT-Guided Reperfusion in STEMI With Early Infarct Artery Patency.

OBJECTIVES: The aim of this study was to test whether optical coherence tomographic (OCT) guidance would provide additional useful information beyond that obtained by angiography and lead to a shift in reperfusion strategy and improved clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) with early infarct artery patency. BACKGROUND: Angiography is limited in assessing the underlying pathophysiological mechanisms of the culprit lesion. METHODS: EROSION III (Optical Coherence Tomography-Guided Reperfusion in ST-Segment Elevation Myocardial Infarction With Early Infarct Artery Patency) is an open-label, prospective, multicenter, randomized, controlled study approved by the ethics committees of participating centers. Patients with STEMI who had angiographic diameter stenosis ≤ 70% and TIMI (Thrombolysis In Myocardial Infarction) flow grade 3 at presentation or after antegrade blood flow restoration were recruited and randomized to either OCT guidance or angiographic guidance. The primary efficacy endpoint was the rate of stent implantation. RESULTS: Among 246 randomized patients, 226 (91.9%) constituted the per protocol set (112 with OCT guidance and 114 with angiographic guidance). The median diameter stenosis was 54.0% (IQR: 48.0%-61.0%) in the OCT guidance group and 53.5% (IQR: 43.8%-64.0%) in the angiographic guidance group (P = 0.57) before randomization. Stent implantation was performed in 49 of 112 patients (43.8%) in the OCT group and 67 of 114 patients (58.8%) in the angiographic group (P = 0.024), demonstrating a 15% reduction in stent implantation with OCT guidance. In patients treated with stent implantation, OCT guidance was associated with a favorable result with lower residual angiographic diameter stenosis (8.7% ± 3.7% vs 11.8% ± 4.6% in the angiographic guidance group; P < 0.001). Two patients (1 cardiac death, 1 stable angina) met the primary safety endpoint in the OCT guidance group, as did 3 patients (3 cardiac deaths) in the angiographic guidance group (1.8% vs 2.6%; P = 0.67). Reinfarction was not observed in either group. At 1 year, the rates of predefined cardiocerebrovascular events were comparable between the groups (11.6% after OCT guidance vs 9.6% after angiographic guidance; P = 0.66). CONCLUSIONS: In patients with STEMI with early infarct artery patency, OCT guidance compared with angiographic guidance of reperfusion was associated with less stent implantation during primary percutaneous coronary intervention. These favorable results indicate the value of OCT imaging in optimizing the reperfusion strategy of patients with STEMI. (EROSION III: OCT- vs Angio-Based Reperfusion Strategy for STEMI; NCT03571269).

[Effects of natural organic soil amendments on quality of Panax notoginseng].

The effects of four natural organic soil amendments on the quality and pesticide residues of Panax notoginseng were investigated through field experiments and the suitable dosage ratio of each soil amendment was selected to provide a new idea for the pollution-free cultivation of P. notoginseng. The four natural organic soil amendments used in this study were Jishibao, Jihuo, Fudujing, and omnipotent nutrients, which were produced by mixed fermentation of aboveground parts of different plants, biological waste residue, and biochar. During the experiments, only four soil amendments were applied to P. notoginseng instead of any pesticides and fertilizers. The experiment was designed as four factors and three levels. There were three dosage gradients(low, medium, and high) for Jishibao(A), Jihuo(B), Fudujing(C), and omnipotent nutrients(D). When the dosage of one soil amendment changed, the do-sage of the other soil amendments remained medium. There were 10 groups in addition to the soil amendment-free group as control(CK). The results showed that the four soil amendments could significantly improve the growth environment of P. notoginseng and increase the seedling survival rate and saponin content of P. notoginseng. The seedling survival rates of the treatment groups increased by 8.24%-30.05% as compared with the control group. Furthermore, the content of pesticide residues in P. notoginseng was too low to be detected, and that of heavy metals in P. notoginseng was far lower than the specified content in the Chinese Pharmacopoeia(2020). The optimal effect was achieved at medium dosage for all the soil amendments with the highest content of saponins, high seedling survival rate, and significantly reduced heavy metals, such as lead, cadmium, arsenic, and mercury.

Optical coherence tomography-guided drug coated balloon in non-small de novo coronary artery lesions: a prospective clinical research.

PURPOSE: The combined use of drug coated balloon (DCB) and optical coherence tomography (OCT) for the treatment of non-small coronary de novo lesion remains to be evaluated. We investigated the safety and efficacy of OCT-guided DCB in non-small coronary de novo lesion patients with predilation of cutting balloon. METHODS: https://clinicaltrials.gov/, ClinicalTrials.gov Identifier: NCT04795144. This study was a prospective, and open-label study. We enrolled patients with non-small de novo lesions treated with OCT-guided DCB. The non-small de novo lesions indicated vessel lesions with a diameter ≥ 2.5 mm. The primary endpoints were the success rate of the procedure and the occurrence of target lesion revascularization. The secondary endpoints were myocardial infarction, cardiac death, and major adverse cardiac events (MACE) within 3 months after the procedure. RESULTS: At the Second Hospital of Jilin University, we enrolled 54 patients (54 lesions) with non-small de novo lesions who were treated with OCT-guided DCB from October 2018 to June 2019. A total of 52 patients were successfully treated with DCB-only strategy, while 2 patients turned to bailout stenting. A total of 21 patients had undergone angiography 3 months after the procedure with the late lumen loss of 0.24±0.57 mm. There was no statistically significant difference in minimal lumen diameter (MLD) between post-DCB and at 3-month angiographic follow-up (2.25±0.40 mm vs 2.04±0.54 mm; P = 0.110). Only 1 patient developed restenosis with the incidence of MACE rate of only 1.92% (n = 1). There was no significant difference in the stenosis of the lumen diameter of the target lesion vessel between 3 months after operation and immediately after operation. CONCLUSIONS: Our study showed that OCT-guided DCB with cutting balloon under guidance may be a novel approach in non-small de novo coronary artery disease.

PREMATURE SENESCENCE LEAF 50 Promotes Heat Stress Tolerance in Rice (Oryza sativa L.).

BACKGROUND: Heat stress is a major environmental factor that could induce premature leaf senescence in plants. So far, a few rice premature senescent leaf mutants have been reported to involve in heat tolerance. FINDINGS: We identified a premature senescence leaf 50 (psl50) mutant that exhibited a higher heat susceptibility with decreased survival rate, over-accumulated hydrogen peroxide (H2O2) content and increased cell death under heat stress compared with the wild-type. The causal gene PREMATURE SENESCENCE LEAF 50 (PSL50) was isolated by using initial map-based resequencing (IMBR) approach, and we found that PSL50 promoted heat tolerance probably by acting as a modulator of H2O2 signaling in response to heat stress in rice (Oryza sativa L.). CONCLUSIONS: PSL50 negatively regulates heat-induced premature leaf senescence in rice.

OsNAC109 regulates senescence, growth and development by altering the expression of senescence- and phytohormone-associated genes in rice.

KEY MESSAGE: We demonstrate that OsNAC109 regulates senescence, growth and development via binding to the cis-element CNTCSSNNSCAVG and altering the expression of multiple senescence- and hormone-associated genes in rice. The NAC family is one of the largest transcripton factor families in plants and plays an essential role in plant development, leaf senescence and responses to biotic/abiotic stresses through modulating the expression of numerous genes. Here, we isolated and characterized a novel yellow leaf 3 (yl3) mutant exhibiting arrested-growth, increased accumulation of reactive oxygen species (ROS), decreased level of soluble proteins, increased level of malondialdehyde (MDA), reduced activities of ROS scavenging enzymes, altered expression of photosynthesis and senescence/hormone-associated genes. The yellow leaf and arrested-growth trait was controlled by a single recessive gene located to chromosome 9. A single nucleotide substitution was detected in the mutant allele leading to premature termination of its coding protein. Genetic complementation could rescue the mutant phenotype while the YL3 knockout lines displayed similar phenotype to WT. YL3 was expressed in all tissues tested and predicted to encode a transcriptional factor OsNAC109 which localizes to the nucleus. It was confirmed that OsNAC109 could directly regulate the expression of OsNAP, OsNYC3, OsEATB, OsAMTR1, OsZFP185, OsMPS and OsGA2ox3 by targeting to the highly conserved cis-element CNTCSSNNSCAVG except OsSAMS1. Our results demonstrated that OsNAC109 is essential to rice leaf senescence, growth and development through regulating the expression of senescence- and phytohormone-associated genes in rice.

Characterization of a novel allele encoding pheophorbide a oxygenase in rice.

We identified a rapid cell death 2 (rcd2) mutant from an indica cultivar Zhongjian100 mutant bank. The red-brown lesions appeared firstly on young seedling leaves, then gradually merged and the leaves completely withered at the late tillering stage. rcd2 displayed apparent cell death at/around the lesions, accumulation of superoxide anion (O2-) and disturbed ROS scavenging system, impaired photosynthetic capacity with significantly reduced chlorophyll content. The lesion formation was controlled by a single recessive nuclear gene and induced by natural light as well as mechanical wounding. A single base mutation (A1726T) at the 6th exon of OsMH_03G0040800 resulted in I576F substitution in the encoding protein, pheophorbide a oxygenase (PAO). Functional complementation could rescue the mutant phenotype and PAO-knockout lines exhibited the similar phenotype to rcd2. The activity of PAO decreased significantly while the content of PAO substrate, pheophorbide a, increased apparently in rcd2. The expression of chlorophyll synthesis/degradation-related genes and the contents of metabolic intermediates were largely changed. Furthermore, the level of chlorophyllide a, the product of chlorophyllase, increased significantly, indicating chlorophyllase might play a role in chlorophyll degradation in rice. Our results suggested that the I576F substitution disrupted PAO function, leading to O2- accumulation and chlorophyll degradation breakdown in rice.

Chloroplast SRP54s are Essential for Chloroplast Development in Rice.

BACKGROUND: The chloroplast signal recognition particle 54 (cpSRP54) is known for targeting the light-harvesting complex proteins to thylakoids and plays a critical role for chloroplast development in Arabidopsis, but little is known in rice. Here, we reported two homologous cpSRP54s that affect chloroplast development and plant survival in rice. RESULTS: Two rice cpSRP54 homologues, OscpSRP54a and OscpSRP54b, were identified in present study. The defective OscpSRP54a (LOC_Os11g05552) was responsible for the pale green leaf phenotype of the viable pale green leaf 14 (pgl14) mutant. A single nucleotide substitution from G to A at the position 278, the first intron splicing site, was detected in LOC_Os11g05552 in pgl14. The wild type allele could rescue the mutant phenotype. Knockout lines of OscpSRP54b (LOC_Os11g05556) exhibited similar pale green phenotype to pgl14 with reduced chlorophyll contents and impaired chloroplast development, but showed apparently arrested-growth and died within 3 weeks. Both OscpSRP54a and OscpSRP54b were constitutively expressed mainly in shoots and leaves at the vegetative growth stage. Subcellular location indicated that both OscpSRP54a and OscpSRP54b were chloroplast-localized. Both OscpSRP54a and OscpSRP54b were able to interact with OscpSRP43, respectively. The transcript level of OscpSRP43 was significantly reduced while the transcript level of OscpSRP54b was apparently increased in pgl14. In contrast, the transcript levels of OscpSRP54a, OscpSRP43 and OscpSRP54b were all significantly decreased in OscpSRP54b knockout lines. CONCLUSION: Our study demonstrated that both OscpSRP54a and OscpSRP54b were essential for normal chloroplast development by interacting with OscpSRP43 in rice. OscpSRP54a and OscpSRP54b might play distinct roles in transporting different chloroplast proteins into thylakoids through cpSRP-mediated pathway.

The OsABCI7 Transporter Interacts with OsHCF222 to Stabilize the Thylakoid Membrane in Rice.

The thylakoid membrane is a highly complex membrane system in plants and plays crucial roles in the biogenesis of the photosynthetic apparatus and plant development. However, the genetic factors involved in chloroplast development and its relationship with intracellular metabolites are largely unknown. Here, a rice (Oryza sativa) chlorotic and necrotic leaf1 (cnl1) mutant was identified and map-based cloning revealed that a single base substitution followed by a 6-bp deletion in the ATP-binding cassette transporter I family member7 (OsABCI7) resulted in chlorotic and necrotic leaves with thylakoid membrane degradation, chlorophyll breakdown, photosynthesis impairment, and cell death in cnl1 Furthermore, the expression of OsABCI7 was inducible under lower temperatures, which severely affected cnl1 chloroplast development, and etiolated cnl1 seedlings were unable to recover to a normal green state under light conditions. Functional complementation and overexpression showed that OsABCI7 could rescue the cnl1 chlorotic and necrotic phenotype. OsABCI7 interacted with HIGH CHLOROPHYLL FLUORESCENCE222 (OsHCF222) to regulate cellular reactive oxygen species (ROS) homeostasis for thylakoid membrane stability. OsABCI7 localized to thylakoid membranes, while OsHCF222 targeted to endoplasmic reticulum and chloroplasts. Exogenous application of ascorbic acid eased the yellowish leaf phenotype by increasing chlorophyll content and alleviating ROS stress in cnl1 Unlike cnl1, the CRISPR/Cas9-mediated OsHCF222 knockout lines showed chlorotic leaves but were seedling lethal. Our results provide insight into the functions of ABC transporters in rice, especially within the relationship between ROS homeostasis and stability of thylakoid membranes.

Serum Exosomal MicroRNA-21, MicroRNA-126, and PTEN Are Novel Biomarkers for Diagnosis of Acute Coronary Syndrome.

Acute coronary syndrome (ACS) is a serious threat to public health. Based on clinical manifestations, ACS can be classified into unstable angina (UA) pectoris and acute myocardial infarction (AMI). The purpose of this study was to explore the possibility of using serum exosomal microRNA (miR)-126, miR-21, and phosphatase and tensin homolog (PTEN) expression levels as biomarkers of UA and AMI and to investigate whether these levels were positively correlated with the severity of coronary stenosis based on the Gensini score. Exosomes were isolated by ultracentrifugation from the serum of 34 patients with AMI, 31 patients with UA, and 22 healthy controls. The isolated exosomes were characterized by electron microscopy and particle size analysis; exosomal identity was further confirmed by western blotting using exosome-specific antibodies. Real-time quantitative polymerase chain reaction indicated that the serum exosomal levels of miR-126 and miR-21 were significantly higher in the patients with UA and AMI than in the healthy controls. Enzyme-linked immunosorbent assay showed that the serum exosomal PTEN levels were significantly higher in the UA and AMI groups than in the control group. Receiving operating characteristic curve analysis demonstrated the diagnostic efficiency of serum exosomal miR-126, miR-21, and PTEN levels for predicting AMI and UA. In addition, the circulating exosomal miR-126 level was positively correlated with the severity of coronary artery stenosis in patients with UA and AMI based on the Gensini score.

Removal, seasonal variation, and environmental impact of parabens in a municipal wastewater treatment facility in Guangzhou, China.

The occurrence, seasonal variation, and environmental impact of five widely used parabens, methyl-(MeP), ethyl-(EtP), n-propyl-(n-PrP), n-butyl-(n-BuP), and benzyl-(BzP) parabens, were investigated in a municipal wastewater treatment plant (WWTP) located in Guangzhou, China, for 1 year. The concentrations of ∑5parabens in the influent and the effluent were 94.2-957 and 0.89-14.7 ng L-1, respectively. The influent paraben concentrations in autumn were significantly lower than in winter, spring, and summer, and the concentrations were generally higher in spring. The removal efficiencies of ∑5parabens in the dissolved phase were over 96%, with high efficiencies in MeP, EtP, and n-PrP. Risk assessment indicated that parabens in the effluent were not likely to pose an environmental risk to aquatic ecosystems. The present study indicates that the treatment processes employed in full-scale WWTPs are effective at removing parabens and highlights the possibility of utilizing WWTPs for restoring water quality in riverine and coastal regions heavily impacted by paraben contamination.

Characterization of a Novel Rice Dynamic Narrow-Rolled Leaf Mutant with Deficiencies in Aromatic Amino Acids.

The leaf blade is the main photosynthetic organ and its morphology is related to light energy capture and conversion efficiency. We isolated a novel rice Dynamic Narrow-Rolled Leaf 1 (dnrl1) mutant showing reduced width of leaf blades, rolled leaves and lower chlorophyll content. The narrow-rolled leaf phenotype resulted from the reduced number of small longitudinal veins per leaf, smaller size and irregular arrangement of bulliform cells compared with the wild-type. DNRL1 was mapped to chromosome 7 and encoded a putative 3-deoxy-7-phosphoheptulonate synthase (DAHPS) which catalyzes the conversion of phosphoenolpyruvate and D-erythrose 4-phosphate to DAHP and phosphate. Sequence analysis revealed that a single base substitution (T-A) was detected in dnrl1, leading to a single amino acid change (L376H) in the coding protein. The mutation led to a lower expression level of DNRL1 as well as the lower activity of DAHPS in the mutant compared with the wild type. Genetic complementation and over-expression of DNRL1 could rescue the narrow-rolled phenotype. DNRL1 was constitutively expressed in all tested organs and exhibited different expression patterns from other narrow-rolled leaf genes. DNRL1-GFP located to chloroplasts. The lower level of chlorophyll in dnrl1 was associated with the downregulation of the genes responsible for chlorophyll biosynthesis and photosynthesis. Furthermore, dnrl1 showed significantly reduced levels of aromatic amino acids including Trp, Phe and Tyr. We conclude that OsDAHPS, encoded by DNRL1, plays a critical role in leaf morphogenesis by mediating the biosynthesis of amino acids in rice.

Occurrence, composition and biological risk of organophosphate esters (OPEs) in water of the Pearl River Estuary, South China.

Since the production of brominated flame retardants has been gradually phased out, organophosphate esters (OPEs) are increasingly used as the substitutes. Given their toxicity and water solubility, OPEs may jeopardize the aquatic environment and organisms. Here, we examined the concentration, composition, and biological risk of OPEs in the water collected from the eight major waterways in the Pearl River Delta, a highly industrialized region in China. We found a widespread occurrence of OPEs in this region (∑9OPEs: 134 to 442 ng L-1), dominated by TCPP, TCEP, and TnBP. Halogenated OPEs were dominant over alkyl and aromatic OPEs. The biological risk of OPEs, mainly contributed by TPhP and TnBP, was low (RQ < 0.1). The contamination level of OPEs in the Pearl River Delta was likely associated with the degree of industrial activities. Although OPEs posed low risk to aquatic organisms, more attention should be paid to some OPEs in the future, such as TnBP, due to the high usage and toxicity. Considering the concentrations of OPEs worldwide and their usage, OPEs may become the emerging pollutants of global concern in the next decade.

Coronary sequelae of Kawasaki disease treated with rotational atherectomy and drug coated balloon: A case report.

INTRODUCTION: Kawasaki disease (KD) is an acute vasculitis syndrome that mainly affects children and is the first cause of acquired heart disease. Coronary artery lesion is the most serious complication of KD. Only two previous studies have reported similar cases, but we reported patient was younger and had a longer follow-up. PATIENT CONCERNS: We reported a case of coronary sequelae of KD treated with rotational atherectomy and drug coated balloon (DCB). During the week after surgery, the patient complained of a slight chest pain intermittently, but no longer appeared after that. DIAGNOSIS: We diagnosed by electrocardiogram and angiography. Angiography showed that the anterior descending branch (LAD) proximal stenosis was 95%, the right coronary artery (RCA) middle stenosis was 99%, and the calcification was severe. INTERVENTIONS: We treat the patient with rotational atherectomy using a 1.25 mm burr, pre-dilatation of the stenosis lesion with a 3.5 mm × 15 mm non-compliant balloon was achieved. Then 3.5 mm × 15 mm drug eluting balloon was inflated at 10 atm for 60 seconds. OUTCOMES: After the 6-month follow-up (from October 2018 to March 2019), the symptom of angina disappeared. Coronary angiography 6 months later showed no apparent progression of vessel narrowing. CONCLUSION: The present case suggests that rotational atherectomy followed by DCB dilation could be an alternative revascularization therapy of choice in coronary KD sequelae complicated with atherosclerosis.

OsCDC48/48E complex is required for plant survival in rice (Oryza sativa L.).

KEY MESSAGE: We demonstrate that the C-terminus of OsCDC48 is essential for maintaining its full ATPase activity and OsCDC48/48E interaction is required to modulate cellular processes and plant survival in rice. Cell division cycle 48 (CDC48) belongs to the superfamily protein of ATPases associated with diverse cellular activities (AAA). We previously isolated a rice CDC48 mutant (psd128) displaying premature senescence and death phenotype. Here, we showed that OsCDC48 (Os03g0151800) interacted with OsCDC48E (Os10g0442600), a homologue of OsCDC48, to control plant survival in rice. OsCDC48E knockout plants exhibited similar behavior to psd128 with premature senescence and plant death. Removal of the C-terminus of OsCDC48 caused altered expression of cell cycle-related genes, changed the percentage of cells in G1 and G2/M phases, and abolished the interaction between OsCDC48 itself and between OsCDC48 and OsCDC48E, respectively. Furthermore, the truncated OsCDC48-PSD128 protein lacking the C-terminal 27 amino acid residues showed a decreased level of ATPase activity. Overexpression of OsCDC48-psd128 resulted in differential expression of AAA-ATPase associated genes leading to increased total ATPase activity, accumulation of reactive oxygen species and decreased plant tiller numbers while overexpression of OsCDC48 also resulted in differential expression of AAA-ATPase associated genes leading to increased total ATPase activity, but increased plant tiller numbers and grain yield, indicating its potential utilization for yield improvement. Our results demonstrated that the C-terminal region of OsCDC48 was essential for maintaining the full ATPase activity and OsCDC48/48E complex might function in form of heteromultimers to modulate cellular processes and plant survival in rice.

Trace metals in e-waste lead to serious health risk through consumption of rice growing near an abandoned e-waste recycling site: Comparisons with PBDEs and AHFRs.

Despite the endeavour to eradicate informal e-waste recycling, remediation of polluted sites is not mandatory in many developing countries and thus the hazard of pollutants remaining in soil is often overlooked. It is noteworthy that a majority of previous studies only analysed a few pollutants in e-waste to reflect the impact of informal e-waste recycling. However, the actual impact may have been largely underestimated since e-waste contains various groups of pollutants and the effect of some emerging pollutants in e-waste remains unexplored. Thus, this study examined the contamination of metals, PBDEs and AHFRs in the vicinity of an abandoned e-waste recycling site. The accumulation and translocation of these pollutants in rice plants cultivated at the nearby paddy field were measured to estimate the health risk through rice consumption. We revealed that the former e-waste burning site was still seriously contaminated with some metals (e.g. Sn, Sb and Ag, Igeo > 5), PBDEs (Igeo > 3) and AHFRs (Igeo > 3), which can disperse to the nearby paddy field and stream. The rice plants can effectively absorb some metals (e.g. Mo, Cr and Mn, BCF > 1), but not PBDEs and AHFRs (BCF < 0.15), from soil and translocate them to the leaves. Alarmingly, the health risk through rice consumption was high primarily due to Sb and Sn (HQ > 20), whereas PBDEs and AHFRs had limited contribution (HQ < 0.08). Our results imply that abandoned e-waste recycling sites still act as the pollution source, jeopardising the surrounding environment and human health. Since some trace metals (e.g. Sb and Sn) are seldom monitored, the impact of informal e-waste recycling would be more notorious than previously thought. Remediation work should be conducted promptly in abandoned e-waste recycling sites to protect the environment and human health.