Experimental Limits on Solar Reflected Dark Matter with a New Approach on Accelerated-Dark-Matter-Electron Analysis in Semiconductors

Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4  kg·day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5-15  keV/c^{2}, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1  MeV/c^{2} is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors.

Boron-mediated amelioration of copper toxicity in Citrus sinensis seedlings involved reduced concentrations of copper in leaves and roots and their cell walls rather than increased copper fractions in their cell walls

Little information is available on how boron (B) supplementation affects plant cell wall (CW) remodeling under copper (Cu) excess. 'Xuegan' (Citrus sinensis) seedlings were submitted to 0.5 or 350 µM Cu × 2.5 or 25 µM B for 24 weeks. Thereafter, we determined the concentrations of CW materials (CWMs) and CW components (CWCs), the degree of pectin methylation (DPM), and the pectin methylesterase (PME) activities and PME gene expression levels in leaves and roots, as well as the Cu concentrations in leaves and roots and their CWMs (CWCs). Additionally, we analyzed the Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectra of leaf and root CWMs. Our findings suggested that adding B reduced the impairment of Cu excess to CWs by reducing the Cu concentrations in leaves and roots and their CWMs and maintaining the stability of CWs, thereby improving leaf and root growth. Cu excess increased the Cu fractions in leaf and root pectin by decreasing DPM due to increased PME activities, thereby contributing to citrus Cu tolerance. FTIR and XRD indicated that the functional groups of the CW pectin, hemicellulose, cellulose, and lignin could bind and immobilize Cu, thereby reducing Cu cytotoxicity in leaves and roots.

Stress Physiology and Molecular Biology of Fruit Crops

Fruit crops provide various kinds of fruit commodities that are of significant nutritional benefit and economic value to humans [...].

Citrus sinensis manganese tolerance: Insight from manganese-stimulated secretion of root exudates and rhizosphere alkalization

We used manganese (Mn)-tolerant 'Xuegan' (Citrus sinensis) seedlings as materials and examined the characterization of Mn uptake and Mn-activated-release of root exudates under hydroponic conditions. We observed that root and shoot Mn bioaccumulation factor (BCF) reduced with the increase of Mn supply, and that Mn transfer factor (Tf) reduced greatly as Mn supply increased from 0 to 500 μM, beyond which Tf slightly increased with increasing Mn supply, suggesting that Mn supply reduced the ability to absorb and accumulate Mn in roots and shoots, as well as root-to-shoot Mn translocation. Without Mn, roots alkalized the solution pH from 5.0 to above 6.2, while Mn supply reduced root-induced alkalization. As Mn supply increased from 0 to 2000 μM, the secretion of root total phenolics (TPs) increased, while the solution pH decreased. Mn supply did not alter the secretion of root total free amino acids, total soluble sugars, malate, and citrate. Mn-activated-release of TPs was inhibited by low temperature and anion channel inhibitors, but not by protein biosynthesis inhibitor. Using widely targeted metabolome, we detected 48 upregulated [35 upregulated phenolic compounds + 13 other secondary metabolites (SMs)] and three downregulated SMs, and 39 upregulated and eight downregulated primary metabolites (PMs). These findings suggested that reduced ability to absorb and accumulate Mn in roots and shoots and less root-to-shoot Mn translocation in Mn-toxic seedlings, rhizosphere alkalization, and Mn-activated-release of root exudates (especially phenolic compounds) contributed to the high Mn tolerance of C. sinensis seedlings.

Regulation of magnesium and calcium homeostasis in citrus seedlings under varying magnesium supply

Magnesium (Mg) and calcium (Ca) are two essential macronutrients in plants; however, the characteristics of Mg and Ca concentrations in organ, subcellular and chemical forms and their relationships in citrus plants, especially under varying Mg supply, are not well understood. In this study, Citrus sinensis seedlings (cv. Xuegan) were cultivated in conditions of Mg deficiency (0 mmol Mg2+ L-1) and Mg sufficiency (2 mmol Mg2+ L-1) to investigate the responses of Mg and Ca homeostasis in different organs and fractions. Compared with Mg sufficiency, Mg deficiency significantly decreased root and shoot growth, with the shoot biomass reduction of branch organs was greater than that of parent organs. In addition to increasing the Ca concentration in the parent stem and lateral root organs, Mg deficiency significantly decreased the concentrations and accumulations of Mg and Ca in citrus seedlings, further altering their distribution in different organs. More than 50% of Ca and Mg were sequestrated in the cell wall and soluble fractions, respectively, with Mg concentration decreasing by 15.4% in roots and 46.9% in leaves under Mg deficiency, while Ca concentration decreased by 27.6% in roots and increased by 23.6% in parent leaves. Approximately 90% of Mg exists in inorganic, water-soluble, and pectate and protein-bound forms, and nearly 90% of Ca exists in water-soluble, pectate and protein-bound, phosphate and oxalate acid forms. Except for the decreased inorganic Mg in roots and water-soluble Mg and Ca in leaves, Mg deficiency increased the proportions of Mg and Ca in all chemical forms. However, Mg deficiency generally increased the Ca/Mg ratio in various organs, subcellular and chemical forms, with negative relationships between Mg concentration and Ca/Mg ratio, and the variations of Mg and Ca were highly separated between Mg supply and organs. In conclusion, our results provide insights into the effects of Mg supply on Mg and Ca homeostasis in citrus plants.

Regulation on copper-tolerance in Citrus sinensis seedlings by boron addition: Insights from root exudates, related metabolism, and gene expression

Boron (B) can alleviate Citrus copper (Cu)-toxicity. However, the underlying mechanism by which B mitigates Cu-toxicity is unclear. 'Xuegan' (Citrus sinensis) seedlings were exposed to 0.5 (control) or 350 (Cu-toxicity) µM Cu and 2.5 or 25 µM B for 24 weeks. Thereafter, we investigated the secretion of low molecular weight compounds [LMWCs; citrate, malate, total soluble sugars (TSS), total phenolics (TP), and total free amino acids (TFAA)] by excised roots and their concentrations in roots and leaves, as well as related enzyme gene expression and activities in roots and leaves. Cu-stress stimulated root release of malate and TFAA, which might contribute to citrus Cu-tolerance. However, B-mediated-mitigation of Cu-stress could not be explained in this way, since B addition failed to further stimulate malate and TFAA secretion. Indeed, B addition decreased Cu-stimulated-secretion of malate. Further analysis suggested that Cu-induced-exudation of malate and TFAA was not regulated by their levels in roots. By contrast, B addition increased malate, citrate, and TFAA concentrations in Cu-toxic roots. Cu-toxicity increased TP concentration in 25 μM B-treated leaves, but not in 2.5 μM B-treated leaves. Our findings suggested that the internal detoxification of Cu by LMWCs played a role in B-mediated-alleviation of Cu-toxicity.

An Integrated Analysis of Metabolome, Transcriptome, and Physiology Revealed the Molecular and Physiological Response of Citrus sinensis Roots to Prolonged Nitrogen Deficiency

Citrus sinensis seedlings were supplied with a nutrient solution containing 15 (control) or 0 (nitrogen (N) deficiency) mM N for 10 weeks. Extensive metabolic and gene reprogramming occurred in 0 mM N-treated roots (RN0) to cope with N deficiency, including: (a) enhancing the ability to keep phosphate homeostasis by elevating the abundances of metabolites containing phosphorus and the compartmentation of phosphate in plastids, and/or downregulating low-phosphate-inducible genes; (b) improving the ability to keep N homeostasis by lowering the levels of metabolites containing N but not phosphorus, upregulating N compound degradation, the root/shoot ratio, and the expression of genes involved in N uptake, and resulting in transitions from N-rich alkaloids to carbon (C)-rich phenylpropanoids and phenolic compounds (excluding indole alkaloids) and from N-rich amino acids to C-rich carbohydrates and organic acids; (c) upregulating the ability to maintain energy homeostasis by increasing energy production (tricarboxylic acid cycle, glycolysis/gluconeogenesis, oxidative phosphorylation, and ATP biosynthetic process) and decreasing energy utilization for amino acid and protein biosynthesis and new root building; (d) elevating the transmembrane transport of metabolites, thus enhancing the remobilization and recycling of useful compounds; and (e) activating protein processing in the endoplasmic reticulum. RN0 had a higher ability to detoxify reactive oxygen species and aldehydes, thus protecting RN0 against oxidative injury and delaying root senescence.

Roles of Hormones in Elevated pH-Mediated Mitigation of Copper Toxicity in Citrus sinensis Revealed by Targeted Metabolome

The effects of copper (Cu)-pH interactions on the levels of hormones and related metabolites (HRMs) in Citrus sinensis leaves and roots were investigated. Our findings indicated that increased pH mitigated Cu toxicity-induced alterations of HRMs, and Cu toxicity increased low-pH-induced alterations of HRMs. Increased pH-mediated decreases in ABA, jasmonates, gibberellins, and cytokinins, increases in (±)strigol and 1-aminocyclopropanecarboxylic acid, and efficient maintenance of salicylates and auxins homeostasis in 300 μM Cu-treated roots (RCu300); as well as efficient maintenance of hormone homeostasis in 300 μM Cu-treated leaves (LCu300) might contribute to improved leaf and root growth. The upregulation of auxins (IAA), cytokinins, gibberellins, ABA, and salicylates in pH 3.0 + 300 μM Cu-treated leaves (P3CL) vs. pH 3.0 + 0.5 μM Cu-treated leaves (P3L) and pH 3.0 + 300 μM Cu-treated roots (P3CR) vs. pH 3.0 + 0.5 μM Cu-treated roots (P3R) might be an adaptive response to Cu toxicity, so as to cope with the increased need for reactive oxygen species and Cu detoxification in LCu300 and RCu300. Increased accumulation of stress-related hormones (jasmonates and ABA) in P3CL vs. P3L and P3CR vs. P3R might reduce photosynthesis and accumulation of dry matter, and trigger leaf and root senescence, thereby inhibiting their growth.

Modeling the charge collection efficiency in the Li-diffused inactive layer of P-type high purity germanium detector

A model of the Li-diffused inactive layer in P-type high purity germanium detectors is built to describe the transportation of charge carriers and calculate the charge collection efficiency therein. The model is applied to calculate charge collection efficiency of a P-type point-contact germanium detector used in rare event physics experiments and validated in another P-type semi-planar germanium detector. The calculated charge collection efficiency curves are well consistent with measurements for both detectors. Effects of the Li doping processes on the charge collection efficiency are discussed based on the model. This model can be easily extended to other P-type germanium detectors, for instance, the P-type broad-energy Ge detector, and the P-type inverted-coaxial point-contact detector.

[Advances in recurrence risk assessment of gastrointestinal stromal tumor]

Identification of prognosis-related risk factors and accurate assessment of risk stratification in patients with gastrointestinal stromal tumor (GIST) is of great significance not only for establishing a reliable prognostic model and developing a follow-up plan but also for selecting potential populations benefiting from neoadjuvant therapies. Although several risk stratification models have been established, it is still challenging to accurately assess patients' risk of recurrence, and the performance of these prediction models still needs to be improved. This review focused on the latest studies in recurrence risk assessment for GIST patients, and summarized potential predictive markers and recurrence risk models related to tumor-related characteristic parameters, novel laboratory examinations, radiological imaging signatures and molecular pathological features, which could provide a reference for accurate risk stratification and individualized targeted therapies for GIST patients.

Characterization of copper-induced-release of exudates by Citrus sinensis roots and their possible roles in copper-tolerance

Copper (Cu) excess is often observed in old Citrus orchards. Little information is available on the characterization of Cu-induced-release of root exudates and their possible roles in plant Cu-tolerance. Using sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] seedlings as materials, we investigated the impacts of 0, 0.5, 25, 150, 350, 550, 1000, 2000 or 5000 μM CuCl₂ (pH 4.8) on Cu uptake, root exudates [malate, citrate, total phenolics (TP), total soluble sugars (TSS) and total free amino acids (TFAA)], electrolyte leakage and malondialdehyde, and solution pH under hydroponic conditions; the time-course of root exudates and solution pH in response to Cu; and the impacts of protein synthesis and anion-channel inhibitors, and temperature on Cu-induced-secretion of root exudates and solution pH. About 70% of Cu was accumulated in 0 and 0.5 μM Cu-exposed roots, while over 97% of Cu was accumulated in ≥25 μM Cu-exposed roots. Without Cu, the seedlings could alkalize the solution pH from 4.8 to above 6.0. Cu-stimulated-secretion of root exudates elevated with the increment of Cu concentration from 0 to 1000 μM, then decreased or remained unchanged with the further increment of Cu concentration, while root electrolyte leakage and malondialdehyde (root-induced alkalization) increased (lessened) with the increment of Cu concentration from 0 to 5000 μM. Further analysis indicated that Cu-stimulated-secretion of root exudates was an energy-dependent process and could repressed by inhibitors, and that there was no discernible delay between the onset of exudate release and the addition of Cu. To conclude, both root-induced alkalization and Cu-stimulated-release of root exudates played a key role in sweet orange Cu-tolerance via increasing root Cu accumulation and reducing Cu uptake and phytotoxicity.

Constraints on Sub-GeV Dark Matter-Electron Scattering from the CDEX-10 Experiment

We present improved germanium-based constraints on sub-GeV dark matter via dark matter-electron (χ-e) scattering using the 205.4  kg·day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted χ-e scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for m_{χ} larger than 80  MeV/c^{2} compared to previous germanium-based χ-e results. We also present the most stringent χ-e cross-section limit to date among experiments using solid-state detectors for m_{χ} larger than 90  MeV/c^{2} with heavy mediators and m_{χ} larger than 100  MeV/c^{2} with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new χ-e detection method with high-purity germanium detectors in ultralow radioactive background.

Exotic Dark Matter Search with the CDEX-10 Experiment at China's Jinping Underground Laboratory

A search for exotic dark matter (DM) in the sub-GeV mass range has been conducted using 205 kg day data taken from a p-type point contact germanium detector of the CDEX-10 experiment at China's Jinping underground laboratory. New low-mass dark matter searching channels, neutral current fermionic DM absorption (χ+A→ν+A) and DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), have been analyzed with an energy threshold of 160 eVee. No significant signal was found; thus new limits on the DM-nucleon interaction cross section are set for both models at the sub-GeV DM mass region. A cross section limit for the fermionic DM absorption is set to be 2.5×10^{-46}  cm^{2} (90% C.L.) at DM mass of 10  MeV/c^{2}. For the DM-nucleus 3→2 scattering scenario, limits are extended to DM mass of 5 and 14  MeV/c^{2} for the massless dark photon and bound DM final state, respectively.

Elevated pH-mediated mitigation of aluminum-toxicity in sweet orange (Citrus sinensis) roots involved the regulation of energy-rich compounds and phytohormones

For the first time, we used targeted metabolome to investigate the effects of pH-aluminum (Al) interactions on energy-rich compounds and their metabolites (ECMs) and phytohormones in sweet orange (Citrus sinensis) roots. The concentration of total ECMs (TECMs) was reduced by Al-toxicity in 4.0-treated roots, but unaffected significantly in pH 3.0-treated roots. However, the concentrations of most ECMs and TECMs were not lower in pH 4.0 + 1.0 mM Al-treated roots (P4AR) than in pH 3.0 + 1.0 mM Al-treated roots (P3AR). Increased pH improved the adaptability of ECMs to Al-toxicity in roots. For example, increased pH improved the utilization efficiency of ECMs and the conversion of organic phosphorus (P) from P-containing ECMs into available phosphate in Al-treated roots. We identified upregulated cytokinins (CKs), downregulated jasmonic acid (JA), methyl jasmonate (MEJA) and jasmonates (JAs), and unaltered indole-3-acetic acid (IAA) and salicylic acid (SA) in P3AR vs pH 3.0 + 0 mM Al-treated roots (P3R); upregulated JA, JAs and IAA, downregulated total CKs, and unaltered MEJA and SA in P4AR vs pH 4.0 + 0 mM Al-treated roots (P4R); and upregulated CKs, downregulated JA, MEJA, JAs and SA, and unaltered IAA in P3AR vs P4AR. Generally viewed, raised pH-mediated increments of JA, MEJA, total JAs, SA and IAA concentrations and reduction of CKs concentration in Al-treated roots might help to maintain nutrient homeostasis, increase Al-toxicity-induced exudation of organic acid anions and the compartmentation of Al in vacuole, and reduce oxidative stress and Al uptake, thereby conferring root Al-tolerance. In short, elevated pH-mediated mitigation of root Al-stress involved the regulation of ECMs and phytohormones.

Effects of Nitrogen Deficiency on the Metabolism of Organic Acids and Amino Acids in Oryza sativa

Organic acids metabolism and nitrogen (N) metabolism in rice seedlings and the relationship between them are not fully understood. In this study, rice (Oryza sativa L. ssp. Indica) variety "Huanghuazhan" was used as the experimental material, and three N levels (5 mM, 1 mM, and 0 mM NH₄NO₃) were set by the hydroponic method for different levels of N treatment. Our results showed that the increased content of malate in rice leaves caused by reducing N level was related to the increased synthesis of malate (the activity of leaf PEPC increased)and the decreased degradation of malate (the activity of leaf NADP-ME decreased), while the increased contents of citrate and isocitrate in rice leaves caused by reducing N level might not be caused by the increased biosynthesis, but due to the decrease in degradation of citrate and isocitrate (the activities of leaf CS, ACO, and NADP-IDH decreased). The increased content of malate in rice roots caused by reducing N level might be related to the increased biosynthesis and the decreased degradation of root malate (the activities of root NAD-MDH and PEPC increased, while the activity of NADP-ME decreased). Compared to the control (5 mM NH₄NO₃), the increased content of citrate in rice roots caused by reducing N level might be related to the increased biosynthesis rather than the decreased degradation of citrate, due to the higher activities of CS and ACO in rice roots under 0 mM N and 1mM N treatment when compared to that of the control ones. At the same time, the increased content of isocitrate in roots was related to the increased isomerization of isocitrate (the activity of root ACO increased) and the decreased degradation of isocitrate (the activity of root NADP-IDH decreased). With the reducing N level, the activities of N metabolism-related enzymes, such as nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT), decreased in rice leaves and roots, resulting in the decreased contents of total free amino acids (TFAAs) and soluble proteins in rice seedlings, and finally led to the growth inhibition. Our results showed that the dynamics of organic acids metabolism caused by reducing N level were different in rice leaves and roots. In conclusion, there was a close correlation between organic acids metabolism and N metabolism in rice leaves and roots under N-limited conditions; furthermore, such a correlation was more obvious in rice leaves than that of roots.

Adaptive responses of carbon and nitrogen metabolisms to nitrogen-deficiency in Citrus sinensis seedlings

BACKGROUND

In China, nitrogen (N)-deficiency often occurs in Citrus orchards, which is one of the main causes of yield loss and fruit quality decline. Little information is known about the adaptive responses of Citrus carbon (C) and N metabolisms to N-deficiency. Seedlings of 'Xuegan' (Citrus sinensis (L.) Osbeck) were supplied with nutrient solution at an N concentration of 0 (N-deficiency), 5, 10, 15 or 20 mM for 10 weeks. Thereafter, we examined the effects of N supply on the levels of C and N in roots, stems and leaves, and the levels of organic acids, nonstructural carbohydrates, NH₄⁺-N, NO₃^--N, total soluble proteins, free amino acids (FAAs) and derivatives (FAADs), and the activities of key enzymes related to N assimilation and organic acid metabolism in roots and leaves.

RESULTS

N-deficiency elevated sucrose export from leaves to roots, C and N distributions in roots and C/N ratio in roots, stems and leaves, thus enhancing root dry weight/shoot dry weight ratio and N use efficiency. N-deficient leaves displayed decreased accumulation of starch and total nonstructural carbohydrates (TNC) and increased sucrose/starch ratio as well as a partitioning trend of assimilated C toward to sucrose, but N-deficient roots displayed elevated accumulation of starch and TNC and reduced sucrose/starch ratio as well as a partitioning trend of assimilated C toward to starch. N-deficiency reduced the concentrations of most FAADs and the ratios of total FAADs (TFAADs)/N in leaves and roots. N-deficiency reduced the demand for C skeleton precursors for amino acid biosynthesis, thus lowering TFAADs/C ratio in leaves and roots. N-deficiency increased (decreased) the relative amounts of C-rich (N-rich) FAADs, thus increasing the molar ratio of C/N in TFAADs in leaves and roots.

CONCLUSIONS

Our findings corroborated our hypothesis that C and N metabolisms displayed adaptive responses to N-deficiency in C. sinensis seedlings, and that some differences existed between roots and leaves in N-deficiency-induced alterations of and C and N metabolisms.

Molecular mechanisms for pH-mediated amelioration of aluminum-toxicity revealed by conjoint analysis of transcriptome and metabolome in Citrus sinensis roots

Little is known about the effects of pH-aluminum (Al) interactions on gene expression and/or metabolite profiles in plants. Eleven-week-old seedlings of Citrus sinensis were fertilized with nutrient solution at an Al level of 0 or 1 mM and a pH of 3.0 or 4.0 for 18 weeks. Increased pH mitigated Al-toxicity-induced accumulation of callose, an Al-sensitive marker. In this study, we identified more differentially expressed genes and differentially abundant metabolites in pH 4.0 + 1 mM Al-treated roots (P4AR) vs pH 4.0 + 0 mM Al-treated roots (P4R) than in pH 3.0 + 1 mM Al-treated roots (P3AR) vs pH 3.0 + 0 mM Al-treated roots (P3R), suggesting that increased pH enhanced root metabolic adaptations to Al-toxicity. Further analysis indicated that increased pH-mediated mitigation of root Al-toxicity might be related to several factors, including: enhanced capacity to maintain the homeostasis of phosphate and energy and the balance between generation and scavenging of reactive oxygen species and aldehydes; and elevated accumulation of secondary metabolites such as polyphenol, proanthocyanidins and phenolamides and adaptations of cell wall and plasma membrane to Al-toxicity.

[Functional outcomes of 100 patients with adenocarcinoma of the esophagogastric junction undergoing Cheng's GIRAFFE(®) reconstruction after proximal gastrectomy]

Objective: To investigate the functional outcomes and postoperative complications of Cheng's GIRAFFE reconstruction after proximal gastrectomy. Methods: A descriptive case series study was conducted. Clinical data of 100 patients with adenocarcinoma of the esophagogastric junction who underwent Cheng's GIRAFFE reconstruction after proximal gastrectomy in Cancer Hospital of University of Chinese Academy of Sciences (64 cases), Zhejiang Provincial Hospital of Chinese Medicine (24 cases), Lishui Central Hospital (10 cases), Huzhou Central Hospital (1 case) and Ningbo Lihuili Hospital (1 case) from September 2017 to June 2021 were retrospectively analyzed. Of 100 patients, 64 were males and 36 were females; the mean age was (61.3 ± 11.1) years and the BMI was (22.7±11.1) kg/m(2). For TNM stage, 68 patients were stage IA, 24 were stage IIA and 8 were stage IIB. Postoperative functional results and postoperative complications of radical gastrectomy with Giraffe reconstruction were analyzed and summarized. Gastroesophageal reflux disease questionnaire (RDQ) score and postoperative endoscopy were used to evaluate the occurrence of reflux esophagitis and its grade (grade N, grade A, grade B, grade C, and grade D from mild to severe reflux). The continuous data conforming to normal distribution were expressed as (mean ± standard deviation), and those with skewed distribution were presented as median (Q1, Q3). Results: All the 100 patients successfully completed R0 resection, including 77 patients undergoing laparoscopic surgery and 23 patients undergoing laparotomy. The Giraffe anastomosis time was (38.6±14.0) min; the blood loss was (73.0±18.4) ml; the postoperative hospital stay was 9.5 (8.2, 13.0) d; the hospitalization cost was (6.0±0.3) ten thousand yuan. Fourteen cases developed perioperative complications (14.0%), including 7 cases of pleural effusion or pneumonia, 3 cases of anastomotic leakage, 2 cases of gastric emptying disorder, 1 case of gastrointestinal hemorrhage and 1 case of anastomotic stenosis, who were all improved and discharged after symptomatic management. Patients were followed up for (33.3±1.6) months. Eight patients were found to have reflux symptoms by RDQ scale six months after surgery, and 11 patients (11/100,11.0%) were found to have reflux esophagitis by gastroscopy, including 6 in grade A, 3 in grade B, and 2 in grade C. All the patients could control their reflux symptoms with behavioral guidance or oral PPIs. Conclusion: Cheng's GIRAFFE reconstruction has good anti-reflux efficacy and gastric emptying function; it can be one of the choices of reconstruction methods after proximal gastrectomy.

Boron-mediated amelioration of copper-toxicity in sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] seedlings involved reduced damage to roots and improved nutrition and water status

'Xuegan' (Citrus sinensis) seedlings were fertilized 6 times weekly for 24 weeks with 0.5 or 350 μM CuCl2 and 2.5, 10 or 25 μM H3BO3. Cu-toxicity increased Cu uptake per plant (UPP) and Cu concentrations in leaves, stems and roots, decreased water uptake and phosphorus, nitrogen, calcium, magnesium, potassium, sulfur, boron and iron UPP, and increased the ratios of magnesium, potassium, calcium and sulfur UPP to phosphorus UPP and the ratios of leaf magnesium, potassium and calcium concentrations to leaf phosphorus concentration. Many decaying and dead fibrous roots occurred in Cu-toxic seedlings. Cu-toxicity-induced alterations of these parameters and root damage decreased with the increase of boron supply. These results demonstrated that B supplementation lowered Cu uptake and its concentrations in leaves, stems and roots and subsequently alleviated Cu-toxicity-induced damage to root growth and function, thus improving plant nutrient (decreased Cu uptake and efficient maintenance of the other nutrient homeostasis and balance) and water status. Further analysis indicated that the improved nutrition and water status contributed to the boron-mediated amelioration of Cu-toxicity-induced inhibition of seedlings, decline of leaf pigments, large reduction of leaf CO2 assimilation and impairment of leaf photosynthetic electron transport chain revealed by greatly altered chlorophyll a fluorescence (OJIP) transients, reduced maximum quantum yield of primary photochemistry (Fv/Fm), quantum yield for electron transport (ETo/ABS) and total performance index (PIabs,total), and elevated dissipated energy per reaction center (DIo/RC). To conclude, our findings corroborate the hypothesis that B-mediated amelioration of Cu-toxicity involved reduced damage to roots and improved nutrient and water status. Principal component analysis showed that Cu-toxicity-induced changes of above physiological parameters generally decreased with the increase of B supply and that B supply-induced alterations of above physiological parameters was greater in 350 μM Cu-treated than in 0.5 μM Cu-treated seedlings. B and Cu had a significant interactive influence on C. sinensis seedlings.

[Investigate the thyroid function of radiation workers and analysis of influence factors]

Objective: To analyze the thyroid condition and influencing factors of radiation workers, and to provide scientific basis for radiation protection management. Methods: In April 2020, 4308 radiation workers from October 1, 2017 to September 30, 2019 were collected for occupational health examination in Hangzhou Occupational Disease Prevention and Treatment Hospital, the data included basic information, Thyroid hormone level and thyroid color doppler ultrasound results. The thyroid status of radiation workers in different subgroups was compared. The influencing factors of Thyroid nodule were analyzed by multiple logistic regression. Results: 616 radiation workers had abnormal thyroid gland (14.3%, 616/4308) . The main manifestations of thyroid gland abnormality were abnormal Thyroid nodule (5.1%, 220/4308) and abnormal TSH level (7.1%, 308/4308) . Compared with the male radiation workers, the abnormal rate of Thyroid nodule, T3 and Tsh in female radiation workers was higher (P<0.05) , and the abnormal rate of Thyroid nodule, T3 and T4 increased with the increase of working age (P<0.05) . Radiation Workers in non-rated medical institutions and private medical institutions had the highest detection rate of Thyroid nodule (P<0.05) , and there was no significant difference in thyroid abnormalities among Workers (P<0.05) . By multiple logistic regression analysis, Sex (female) , age and institution type (private) were all independent risk factors for Thyroid nodule (95% CI: 1.548~2.763、1.002~1.030, P<0.05) . Conclusion: Ionizing radiation can cause thyroid damage in radiation workers, so we should pay more attention to the radiation protection management of female, high age, private and district medical organizations, so as to protect the health of radiation workers.

Citrus Physiological and Molecular Response to Boron Stresses

Since the essentiality of boron (B) to plant growth was reported nearly one century ago, the implication of B in physiological performance, productivity and quality of agricultural products, and the morphogenesis of apical meristem in plants has widely been studied. B stresses (B deficiency and toxicity), which lead to atrophy of canopy and deterioration of Citrus fruits, have long been discovered in citrus orchards. This paper reviews the research progress of B stresses on Citrus growth, photosynthesis, light use efficiency, nutrient absorption, organic acid metabolism, sugar metabolism and relocation, and antioxidant system. Moreover, the beneficial effects of B on plant stress tolerance and further research in this area were also discussed.

Metabolomics combined with physiology and transcriptomics reveals how Citrus grandis leaves cope with copper-toxicity

Limited data are available on metabolic responses of plants to copper (Cu)-toxicity. Firstly, we investigated Cu-toxic effects on metabolomics, the levels of free amino acids, NH₄⁺-N, NO₃^--N, total nitrogen, total soluble proteins, total phenolics, lignin, reduced glutathione (GSH) and malondialdehyde, and the activities of nitrogen-assimilatory enzymes in 'Shatian' pummelo (Citrus grandis) leaves. Then, a conjoint analysis of metabolomics, physiology and transcriptomics was performed. Herein, 59 upregulated [30 primary metabolites (PMs) and 29 secondary metabolites (SMs)] and 52 downregulated (31 PMs and 21 SMs) metabolites were identified in Cu-toxic leaves. The toxicity of Cu to leaves was related to the Cu-induced accumulation of NH₄⁺ and decrease of nitrogen assimilation. Metabolomics combined with physiology and transcriptomics revealed some adaptive responses of C. grandis leaves to Cu-toxicity, including (a) enhancing tryptophan metabolism and the levels of some amino acids and derivatives (tryptophan, phenylalanine, 5-hydroxy-l-tryptophan, 5-oxoproline and GSH); (b) increasing the accumulation of carbohydrates and alcohols and upregulating tricarboxylic acid cycle and the levels of some organic acids and derivatives (chlorogenic acid, quinic acid, d-tartaric acid and gallic acid o-hexoside); (c) reducing phospholipid (lysophosphatidylcholine and lysophosphatidylethanolamine) levels, increasing non-phosphate containing lipid [monoacylglycerol ester (acyl 18:2) isomer 1] levels, and inducing low-phosphate-responsive gene expression; and (d) triggering the biosynthesis of some chelators (total phenolics, lignin, l-trytamine, indole, eriodictyol C-hexoside, quercetin 5-O-malonylhexosyl-hexoside, N-caffeoyl agmatine, N'-p-coumaroyl agmatine, hydroxy-methoxycinnamate and protocatechuic acid o-glucoside) and vitamins and derivatives (nicotinic acid-hexoside, B₁ and methyl nicotinate). Cu-induced upregulation of many antioxidants could not protect Cu-toxic leaves from oxidative damage. To conclude, our findings corroborated the hypothesis that extensive reprogramming of metabolites was carried out in Cu-toxic C. grandis leaves in order to cope with Cu-toxicity.

Prevalence of bicuspid aortic valve in patients with aneurysmal sub-arachnoid hemorrhage: neurologic features and outcomes

Background

Intracranial aneurysm (IA) has been associated with bicuspid aortic valve (BAV) with prevalence of 6–10% which has led some to recommend routine surveillance for IA in BAV patients. Higher incidence of IA in BAV could signal towards systemic arteriopathy beyond the thoracic aorta. With CoA as an independent risk factor for IA formation, it is currently uncertain if the association between IA and BAV reflects the association of BAV and CoA, or the result of BAV-related systemic arterial changes.

Purpose

Despite this association, 2 small studies suggest no increased risk of the most important patient outcome: aneurysmal sub-arachnoid hemorrhage (aSAH). Our primary aim was identifying the prevalence of BAV in aSAH patients and compare it with that of a control group without aSAH. Secondary aims included neurologic outcomes of aSAH and anatomical characteristics of IA in BAV, and final disposition and outcome.

Methods

Patients (&gt;18 years age) with an accurate diagnosis of aSAH and at least one echocardiogram in the system between January 2000-December 2019 were identified from a prospectively maintained registry of aSAH admissions. Controls, without a diagnosis of SAH ever, were age- and gender-matched (1:2 cases:controls). BAV prevalence was echocardiographically-confirmed in all patients. Severity of aSAH was categorized using the modified Fisher (mFisher) and the World Federation of Neurological Scale (WFNS).

Results

A total of 488 aSAH cases and 990 controls were included in the final analysis with confirmed aortic valve status. The prevalence of BAV in aSAH patients was 1.2% (6/488) vs 3.5% (35/990) in controls, p=0.01. None of the aSAH cases were noted to have CoA, whereas 3 (0.3%; p=0.12) control patients had presence of both BAV and CoA. Within aSAH patients, BAV+aSAH were noted to be younger than tricuspid aortic valve (TAV)+aSAH (56±11 vs 68±14; p=0.03). Aneurysm size was smaller in the BAV+aSAH group (5±2 vs 7±4 in TAV+aSAH; p=0.31). The severity of the bleed was lesser in BAV+aSAH than TAV+aSAH (mFisher grade &gt;2 50% vs 74%; p=0.19, WFNS grade &gt;3 17% vs 36%; p=0.43) which is clinically significant. The BAV+aSAH group had higher disposition rate to home (67% vs 39%; p=0.21) with no difference in in-hospital mortality rates (17% vs 18%; p=0.93). BAV had lower odds on univariate and multivariate analyses adjusted for age/sex/body mass index (OR 0.33 [CI 0.14–0.81]; p=0.01, OR 0.23 [CI 0.08–0.65]; p=0.01) of presenting with aSAH.

Conclusion

Within a large prospective registry with accurate aSAH diagnoses, we found 3-times lower prevalence of echocardiographically-confirmed BAV as compared to non-aSAH controls. We observed 3-times higher prevalence of BAV in controls than among aSAH cases. In addition, size of intracranial aneurysms was clinically smaller in BAV patients, and the severity of SAH was significantly lesser in BAV from a clinical standpoint. Our findings argue against routine surveillance for IA in BAV patients without CoA.

Funding Acknowledgement

Type of funding sources: None.

Effects of phosphorus deficiency on the absorption of mineral nutrients, photosynthetic system performance and antioxidant metabolism in Citrus grandis

Phosphorus (P) is an essential macronutrient for plant growth, development and production. However, little is known about the effects of P deficiency on nutrient absorption, photosynthetic apparatus performance and antioxidant metabolism in citrus. Seedlings of 'sour pummelo' (Citrus grandis) were irrigated with a nutrient solution containing 0.2 mM (Control) or 0 mM (P deficiency) KH2PO4 until saturated every other day for 16 weeks. P deficiency significantly decreased the dry weight (DW) of leaves and stems, and increased the root/shoot ratio in C. grandis but did not affect the DW of roots. The decreased DW of leaves and stems might be induced by the decreased chlorophyll (Chl) contents and CO2 assimilation in P deficient seedlings. P deficiency heterogeneously affected the nutrient contents of leaves, stems and roots. The analysis of Chl a fluorescence transients showed that P deficiency impaired electron transport from the donor side of photosystem II (PSII) to the end acceptor side of PSI, which showed a greater impact on the performance of the donor side of PSII than that of the acceptor side of PSII and photosystem I (PSI). P deficiency increased the contents of ascorbate (ASC), H2O2 and malondialdehyde (MDA) as well as the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) in leaves. In contrast, P deficiency increased the ASC content, reduced the glutathione (GSH) content and the activities of SOD, CAT, APX and monodehydroascorbate reductase (MDHAR), but did not increase H2O2 production, anthocyanins and MDA content in roots. Taking these results together, we conclude that P deficiency affects nutrient absorption and lowers photosynthetic performance, leading to ROS production, which might be a crucial cause of the inhibited growth of C. grandis.

Molecular mechanisms for magnesium-deficiency-induced leaf vein lignification, enlargement and cracking in Citrus sinensis revealed by RNA-Seq

Citrus sinensis (L.) Osbeck seedlings were fertigated with nutrient solution containing 2 [magnesium (Mg)-sufficiency] or 0 mM (Mg-deficiency) Mg(NO3)2 for 16 weeks. Thereafter, RNA-Seq was used to investigate Mg-deficiency-responsive genes in the veins of upper and lower leaves in order to understand the molecular mechanisms for Mg-deficiency-induced vein lignification, enlargement and cracking, which appeared only in the lower leaves. In this study, 3065 upregulated and 1220 downregulated, and 1390 upregulated and 375 downregulated genes were identified in Mg-deficiency veins of lower leaves (MDVLL) vs Mg-sufficiency veins of lower leaves (MSVLL) and Mg-deficiency veins of upper leaves (MDVUL) vs Mg-sufficiency veins of upper leaves (MSVUL), respectively. There were 1473 common differentially expressed genes (DEGs) between MDVLL vs MSVLL and MDVUL vs MSVUL, 1463 of which displayed the same expression trend. Magnesium-deficiency-induced lignification, enlargement and cracking in veins of lower leaves might be related to the following factors: (i) numerous transciption factors and genes involved in lignin biosynthesis pathways, regulation of cell cycle and cell wall metabolism were upregulated; and (ii) reactive oxygen species, phytohormone and cell wall integrity signalings were activated. Conjoint analysis of proteome and transcriptome indicated that there were 287 and 56 common elements between DEGs and differentially abundant proteins (DAPs) identified in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively, and that among these common elements, the abundances of 198 and 55 DAPs matched well with the transcript levels of the corresponding DEGs in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively, indicating the existence of concordances between protein and transcript levels.

Raised pH conferred the ability to maintain a balance between production and detoxification of reactive oxygen species and methylglyoxal in aluminum-toxic Citrus sinensis leaves and roots

Little is known about interactive effects of pH-aluminum (Al) on reactive oxygen species (ROS) and methylglyoxal (MG) metabolisms in plants. Citrus sinensis seedlings were fertilized with nutrient solution at an Al concentration of 1 or 0 mM and a pH of 4.0, 3.5, 3.0 or 2.5 for 18 weeks. Thereafter, gas exchange and chlorophylls in leaves, H₂O₂ generation, electrolyte leakage, total soluble proteins, MG, malondialdehyde (MDA), antioxidants, sulfur-containing compounds, enzymes [viz., antioxidant enzymes, sulfur metabolism-related enzymes, ascorbate oxidase, phosphomannose isomerase, glyoxalase I and glyoxalase II] involved in ROS and MG detoxification in leaves and roots were measured. Effects of low pH and Al-toxicity on these parameters displayed obvious synergism. Without Al-toxicity, low pH increased H₂O₂ production, electrolyte leakage, MDA and MG concentrations by 45.7%-90.3% (52.4%-73.6%), 24.3%-74.5% (26.7%-86.2%), 18.6%-44.8% (35.6%-53.7%) and 16.3%-47.1% (13.8%-51.7%) in leaves (roots) relative to pH 4, respectively; low pH-induced upregulation of enzymes involved in ROS and MG detoxification and sulfur-containing compounds in leaves and/or roots could not protect them against oxidative damage. At pH 2.5-3.0, Al-toxicity increased H₂O₂ production, electrolyte leakage, MDA and MG concentrations by 34.2%-35.5% (23.9%-72.7%), 10.2%-29.5% (23.7%-56.8%), 15.6%-35.7% (27.5%-33.9%) and 21.5%-26.8% (21.0%-49.2%) in leaves (roots), respectively, and decreased total soluble protein concentration by 46.2%-47.4% (18.8%-20.8%) in leaves (roots); at pH 3.5-4.0, Al-toxicity did not affect significantly the five parameters in leaves and roots except for Al-induced increases in root MDA concentration at pH 3.5-4.0 and root electrolyte leakage at pH 3.5, and Al-induced decrease in root total soluble protein concentration at pH 4.0. Raised pH conferred the ability to maintain a balance between production and detoxification of ROS and MG in leaves and roots, thus protecting them against oxidative damage, and hence alleviating Al-induced increase in electrolyte leakage and decrease in total soluble protein level.

Illumina sequencing revealed roles of microRNAs in different aluminum tolerance of two citrus species

Self-germinated seedlings of Citrus sinensis and C. grandis were supplied with nutrient solution with 0 mM AlCl₃·6H₂O (control, -Al) or 1 mM AlCl₃·6H₂O (+Al) for 18 weeks. The DW (Dry weights) of leaf, stem, shoot and the whole plant of C. grandis were decreased and the ratio of root DW to shoot DW in C. grandis were increased by Al, whereas these parameters of C. sinensis were not changed by Al. Al treatment dramatically decreased the sulfur (S) content in C. grandis roots and the phosphorus (P) content in both C. sinensis and C. grandis roots. More Al was transported to shoots and leaves in C. grandis than in C. sinensis under Al treatment. Al treatment has more adverse effects on C. grandis than on C. sinensis, as revealed by the higher production of superoxide anion (O₂ ^·-), H₂O₂ and thiobarbituric acid reactive substace (TBARS) content in C. grandis roots. Via the Illumina sequencing technique, we successfully identified and quantified 12 and 16 differentially expressed miRNAs responding to Al stress in C. sinensis and C. grandis roots, respectively. The possible mechanism underlying different Al tolerance of C. sinensis and C. grandis were summarized as having following aspects: (a) enhancement of adventitious and lateral root development (miR160); (b) up-regulation of stress and signaling transduction related genes, such as SGT1, PLC and AAO (miR477, miR397 and miR398); (c) enhancement of citrate secretion (miR3627); (d) more flexible control of alternative glycolysis pathway and TCA cycle (miR3627 and miR482); (e) up-regulation of S-metabolism (miR172); (f) more flexible control of miRNA metabolism. For the first time, we showed that root development (miR160) and cell wall components (cas-miR5139, csi-miR12105) may play crucial roles in Al tolerance in citrus plants. In conclusion, our study provided a comprehensive profile of differentially expressed miRNAs in response to Al stress between two citrus plants differing in Al tolerance which further enriched our understanding of the molecular mechanism underlying Al tolerance in plants.

Molecular and physiological mechanisms underlying magnesium-deficiency-induced enlargement, cracking and lignification of Citrus sinensis leaf veins

Little is known about the physiological and molecular mechanisms underlying magnesium (Mg)-deficiency-induced enlargement, cracking and lignification of midribs and main lateral veins of Citrus leaves. Citrus sinensis (L.) Osbeck seedlings were irrigated with nutrient solution at a concentration of 0 (Mg-deficiency) or 2 (Mg-sufficiency) mM Mg(NO3)2 for 16 weeks. Enlargement, cracking and lignification of veins occurred only in lower leaves, but not in upper leaves. Total soluble sugars (glucose + fructose + sucrose), starch and cellulose concentrations were less in Mg-deficiency veins of lower leaves (MDVLL) than those in Mg-sufficiency veins of lower leaves (MSVLL), but lignin concentration was higher in MDVLL than that in MSVLL. However, all four parameters were similar between Mg-deficiency veins of upper leaves (MDVUL) and Mg-sufficiency veins of upper leaves (MSVUL). Using label-free, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, we identified 1229 and 492 differentially abundant proteins (DAPs) in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively. Magnesium-deficiency-induced alterations of Mg, nonstructural carbohydrates, cell wall components, and protein profiles were greater in veins of lower leaves than those in veins of upper leaves. The increased concentration of lignin in MDVLL vs MSVLL might be caused by the following factors: (i) repression of cellulose and starch accumulation promoted lignin biosynthesis; (ii) abundances of proteins involved in phenylpropanoid biosynthesis pathway, hormone biosynthesis and glutathione metabolism were increased; and (iii) the abundances of the other DAPs [viz., copper/zinc-superoxide dismutase, ascorbate oxidase (AO) and ABC transporters] involved in lignin biosynthesis were elevated. Also, the abundances of several proteins involved in cell wall metabolism (viz., expansins, Rho GTPase-activating protein gacA, AO, monocopper oxidase-like protein and xyloglucan endotransglucosylase/hydrolase) were increased in MDVLL vs MSVLL, which might be responsible for the enlargement and cracking of leaf veins.

Interactive effects of pH and aluminum on the secretion of organic acid anions by roots and related metabolic factors in Citrus sinensis roots and leaves

Low pH and aluminum (Al)-toxicity often coexist in acidic soils. Citrus sinensis seedlings were treated with nutrient solution at a pH of 2.5, 3.0, 3.5 or 4.0 and an Al concentration of 0 or 1 mM for 18 weeks. Thereafter, malate, citrate, isocitrate, acid-metabolizing enzymes, and nonstructural carbohydrates in roots and leaves, and release of malate and citrate from roots were measured. Al concentration in roots and leaves increased under Al-toxicity, but it declined with elevating nutrient solution pH. Al-toxicity increased the levels of glucose, fructose, sucrose and total soluble sugars in leaves and roots at each given pH except for a similar sucrose level at pH 2.5-3.0, but it reduced or did not alter the levels of starch and total nonstructural carbohydrates (TNC) in leaves and roots with the exception that Al improved TNC level in roots at pH 4.0. Levels of nonstructural carbohydrates in roots and leaves rose with reducing pH with a few exceptions with or without Al-toxicity. A potential model for the possible role of root organic acid (OA) metabolism (anions) in C. sinensis Al-tolerance was proposed. With Al-toxicity, the elevated pH upregulated the OA metabolism, and increased the flow of carbon to OA metabolism, and the accumulation of malate and citrate in roots and subsequent release of them, thus reducing root and leaf Al and hence eliminating Al-toxicity. Without Al-toxicity, low pH stimulated the exudation of malate and citrate, an adaptive response of Citrus to low pH. The interactive effects of pH and pH on OA metabolism were different between roots and leaves.

Direct Detection Constraints on Dark Photons with the CDEX-10 Experiment at the China Jinping Underground Laboratory

We report constraints on the dark photon effective kinetic mixing parameter (κ) with data taken from two p-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on κ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (m_{V}) from 10 to 300  eV/c^{2} in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90% confidence level with m_{V} from 0.1 to 4.0  keV/c^{2} are set from 449.6 kg-day data, with a minimum of κ=1.3×10^{-15} at m_{V}=200  eV/c^{2}.

Excess Copper-Induced Alterations of Protein Profiles and Related Physiological Parameters in Citrus Leaves

This present study examined excess copper (Cu) effects on seedling growth, leaf Cu concentration, gas exchange, and protein profiles identified by a two-dimensional electrophoresis (2-DE) based mass spectrometry (MS) approach after Citrus sinensis and Citrus grandis seedlings were treated for six months with 0.5 (control), 200, 300, or 400 μM CuCl2. Forty-one and 37 differentially abundant protein (DAP) spots were identified in Cu-treated C. grandis and C. sinensis leaves, respectively, including some novel DAPs that were not reported in leaves and/or roots. Most of these DAPs were identified only in C. grandis or C. sinensis leaves. More DAPs increased in abundances than DAPs decreased in abundances were observed in Cu-treated C. grandis leaves, but the opposite was true in Cu-treated C. sinensis leaves. Over 50% of DAPs were associated with photosynthesis, carbohydrate, and energy metabolism. Cu-toxicity-induced reduction in leaf CO2 assimilation might be caused by decreased abundances of proteins related to photosynthetic electron transport chain (PETC) and CO2 assimilation. Cu-effects on PETC were more pronounced in C. sinensis leaves than in C. grandis leaves. DAPs related to antioxidation and detoxification, protein folding and assembly (viz., chaperones and folding catalysts), and signal transduction might be involved in Citrus Cu-toxicity and Cu-tolerance.

[Preliminary efficacy analysis of Cheng's Giraffe reconstruction after proximal gastrectomy in adenocarcinoma of esophagogastric junction]

Objective: To investigate the safety and feasibility of proximal partial gastrectomy with Cheng's Giraffe esophagogastric reconstruction for the treatment of early Siewert II adenocarcinoma of esophagogastric junction (AEG). Methods: Indication of Cheng's Giraffe esophagogastric reconstruction: (1) Siewert II AEG or Siewert III AEG with diameter < 4 cm; (2) preoperative staging as cT1-2N0M0. A descriptive case series study was carried out. Clinical data of 34 patients with Siewert II AEG undergoing proximal partial gastrectomy and Cheng's Giraffe esophagogastric reconstruction at Department of Abdominal Surgery of Zhejiang Cancer Hospital and Department of Gastrointestinal Surgery, The First Affiliated Hospital of Zhejiang University of Traditional Chinese Medicine from February to July 2018 were retrospectively collected and analyzed, including 14 cases in IA stage, 11 cases in IIA stage and 8 cases in IIB stage. Brief procedure of Cheng's Giraffe esophagogastric reconstruction was as follows: Firstly, 12 cm long tubular stomach was formed by longitudinal incision 4 cm away from the great curvature of the stomach. Secondly, the gastric fundus and His angle were formed. Finally, the distance from His angle to esophagal-tubular gastric anastomosis should be more than 5 cm. The reflux disease questionare (RDQ) scores, radionuclide gastric emptying scintigraphy, and 24-hour multichannel intraluminal (MII)-pH monitoring technology were used to evaluate postoperative gastric emptying and gastroesophageal reflux. Result: All 34 patients successfully completed proximal partial gastrectomy with Cheng's Giraffe esophagogastric reconstruction, including 13 cases by open surgery and 21 cases by laparoscopic surgery. The operation time was (144.6±39.8) minutes, the blood loss during operation was (35.4±17.2) ml. No laparoscopic case was converted to open surgery and no postoperative complication was observed. The postoperative hospital stay was (8.4±2.5) days. The postoperative RDQ score was 4.4±3.1 one month after operation, and 3.3±2.5 six months after operation. Gastric-half emptying time was (67.0±21.5) minutes, and the residual ratio was (52.2±7.7)% in 1 hour, (36.4±3.1)% in 2 hours and (28.8±3.6)% in 3 hours at postoperative 1-month. The 24-hour MII-pH monitoring at postoperative 2-month revealed the frequency of acid reflux was (12.6±7.9) times, frequency of non-acid reflux was (19.6±9.7) times, DeMeester score was 5.8±2.9. Conclusion: Cheng's Giraffe esophagogastric reconstruction is safe and feasible in the treatment of Siewert type II AEG, and has good dynamic and anti-reflux effects.

Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (m_{χ}) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at m_{χ}<6  GeV/c^{2} among WIMP AM measurements to date.

Low pH effects on reactive oxygen species and methylglyoxal metabolisms in Citrus roots and leaves

BACKGROUND

Limited data are available on the responses of reactive oxygen species (ROS) and methylglyoxal (MG) metabolisms to low pH in roots and leaves. In China, quite a few of Citrus are cultivated in acidic soils (pH < 5.0). 'Xuegan' (Citrus sinensis) and 'Sour pummelo' (Citrus grandis) (C. sinensis were more tolerant to low pH than C. grandis) seedlings were irrigated daily with nutrient solution at a pH of 2.5, 3 or 5 for nine months. Thereafter, we examined low pH effects on growth, and superoxide anion production rate (SAP), malondialdehyde (MDA), MG, antioxidants, and enzymes related to ROS and MG detoxification in roots and leaves in order to (a) test the hypothesis that low pH affected ROS and MG metabolisms more in roots than those of leaves, and (b) understand the roles of ROS and MG metabolisms in Citrus low pH-tolerance and -toxicity.

RESULTS

Compared with control, most of the physiological parameters related to ROS and MG metabolisms were greatly altered at pH 2.5, but almost unaffected at pH 3. In addition to decreased root growth, many fibrous roots became rotten and died at pH 2.5. pH 2.5-induced changes in SAP, the levels of MDA, MG and antioxidants, and the activities of most enzymes related to ROS and MG metabolisms were greater in roots than those of leaves. Impairment of root ascorbate metabolism was the most serious, especially in C. grandis roots. pH 2.5-induced increases in MDA and MG levels in roots and leaves, decreases in the ratios of ascorbate/(ascorbate+dehydroascorbate) in roots and leaves and of reduced glutathione/(reduced+oxidized glutathione) in roots were greater in C. grandis than those in C. sinensis.

CONCLUSIONS

Low pH affected MG and ROS metabolisms more in roots than those in leaves. The most seriously impaired ascorbate metabolism in roots was suggested to play a role in low pH-induced root death and growth inhibition. Low pH-treated C. sinensis roots and leaves had higher capacity to maintain a balance between ROS and MG production and their removal via detoxification systems than low pH-treated C. grandis ones, thus contribute to the higher acid-tolerance of C. sinensis.

Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jinping Underground Laboratory

We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (m_{χ}) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg day exposure and 250 eVee threshold for AM analysis. The sensitive windows in m_{χ} are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σ_{χN}^{SI} at 90% confidence level are derived as 2×10^{-32}∼7×10^{-35}  cm^{2} for TI analysis at m_{χ}∼50-180  MeV/c^{2}, and 3×10^{-32}∼9×10^{-38}  cm^{2} for AM analysis at m_{χ}∼75  MeV/c^{2}-3.0  GeV/c^{2}.

Phosphorus-mediated alleviation of aluminum toxicity revealed by the iTRAQ technique in Citrus grandis roots

Citrus grandis seedlings were irrigated with nutrient solutions with four Al-P combinations [two Al levels (0 mM and 1.2 mM AlCl3·6H2O) × two P levels (0 μM and 200 μM KH2PO4)] for 18 weeks. Al dramatically inhibited the growth of C. grandis seedlings, as revealed by a decreased dry weight of roots and shoots. Elevating P level could ameliorate the Al-induced growth inhibition and organic acid (malate and citrate) secretion in C. grandis. Using a comparative proteomic approach revealed by the isobaric tags for relative and absolute quantification (iTRAQ) technique, 318 differentially abundant proteins (DAPs) were successfully identified and quantified in this study. The possible mechanisms underlying P-induced alleviation of Al toxicity in C. grandis were proposed. Furthermore, some DAPs, such as GLN phosphoribosyl pyrophosphate amidotransferase 2, ATP-dependent caseinolytic (Clp) protease/crotonase family protein, methionine-S-oxide reductase B2, ABC transporter I family member 17 and pyridoxal phosphate phosphatase, were reported for the first time to respond to Al stress in Citrus plants. Our study provides some proteomic details about the alleviative effects of P on Al toxicity in C. grandis, however, the exact function of the DAPs identified herein in response to Al tolerance in plants must be further investigated.

Excess copper effects on growth, uptake of water and nutrients, carbohydrates, and PSII photochemistry revealed by OJIP transients in Citrus seedlings

Seedlings of 'Shatian pummelo' (Citrus grandis) and 'Xuegan' (Citrus sinensis) were supplied daily with nutrient solution at a concentration of 0.5 (control), 100, 200, 300, 400, or 500 μM CuCl₂ for 6 months. Thereafter, seedling growth; leaf, root, and stem levels of nutrients; leaf gas exchange; levels of pigments; chlorophyll a fluorescence (OJIP) transients and related parameters; leaf and root relative water content; levels of nonstructural carbohydrates; H₂O₂ production rate; and electrolyte leakage were comprehensively examined (a) to test the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth; (b) to establish whether the Cu-induced preferential accumulation of Cu in the roots is involved in Cu tolerance of Citrus; and (c) to elucidate the possible causes for the Cu-induced decrease in photosynthesis. Most of the growth and physiological parameters were greatly altered only at 300-500 μM (excess) Cu-treated seedlings. Cu supply increased the level of Cu in the roots, stems, and leaves, with a greater increase in the roots than that in the stems and leaves. Many of the fibrous roots became rotten and died under excess Cu. These findings support the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth, and the conclusion that the preferential accumulation of Cu in the roots under excess Cu is involved in the tolerance of Citrus to Cu toxicity. The lower CO₂ assimilation in excess Cu-treated leaves was caused mainly by nonstomatal factors, including structural damage to thylakoids, feedback inhibition due to increased accumulation of nonstructural carbohydrates, decreased uptake of water and nutrients, increased production of reactive oxygen species, and impaired photosynthetic electron transport chain. Also, we discussed the possible causes for the excess Cu-induced decrease in leaf pigments and accumulation of nonstructural carbohydrates in the roots and leaves.

Magnesium-Deficiency Effects on Pigments, Photosynthesis and Photosynthetic Electron Transport of Leaves, and Nutrients of Leaf Blades and Veins in Citrus sinensis Seedlings

Citrus sinensis seedlings were irrigated with nutrient solution at a concentration of 0 (Mg-deficiency) or 2 (Mg-sufficiency) mM Mg (NO3)2 for 16 weeks. Mg-deficiency-induced interveinal chlorosis, vein enlargement and corkiness, and alterations of gas exchange, pigments, chlorophyll a fluorescence (OJIP) transients and related parameters were observed in middle and lower leaves, especially in the latter, but not in upper leaves. Mg-deficiency might impair the whole photosynthetic electron transport, including structural damage to thylakoids, ungrouping of photosystem II (PSII), inactivation of oxygen-evolving complex (OEC) and reaction centers (RCs), increased reduction of primary quinone electron acceptor (QA) and plastoquinone pool at PSII acceptor side and oxidation of PSI end-electron acceptors, thus lowering energy transfer and absorption efficiency and the transfer of electrons to the dark reactions, hence, the rate of CO2 assimilation in Mg-deficiency middle and lower leaves. Although potassium, Mg, manganese and zinc concentration in blades displayed a significant and positive relationship with the corresponding element concentration in veins, respectively, great differences existed in Mg-deficiency-induced alterations of nutrient concentrations between leaf blades and veins. For example, Mg-deficiency increased boron level in the blades of upper leaves, decreased boron level in the blades of lower leaves, but did not affect boron level in the blades of middle leaves and veins of upper, middle and lower leaves. To conclude, Mg-deficiency-induced interveinal chlorosis, vein enlargement, and corkiness, and alterations to photosynthesis and related parameters increased with increasing leaf age. Mg-deficiency-induced enlargement and corkiness of veins were not caused by Mg-deficiency-induced boron-starvation.

Magnesium Deficiency Induced Global Transcriptome Change in Citrus sinensis Leaves Revealed by RNA-Seq

Magnesium (Mg) deficiency is one of the major constraining factors that limit the yield and quality of agricultural products. Uniform seedlings of the Citrus sinensis were irrigated with Mg deficient (0 mM MgSO₄) and Mg sufficient (1 mM MgSO₄) nutrient solutions for 16 weeks. CO₂ assimilation, starch, soluble carbohydrates, TBARS content and H₂O₂ production were measured. Transcriptomic analysis of C. sinensis leaves was performed by Illumina sequencing. Our results showed that Mg deficiency decreased CO₂ assimilation, but increased starch, sucrose, TBARS content and H₂O₂ production in C. sinensis leaves. A total of 4864 genes showed differential expression in response to Mg deficiency revealed by RNA-Seq and the transcriptomic data were further validated by real-time quantitative PCR (RT-qPCR). Gene ontology (GO) enrichment analysis indicated that the mechanisms underlying Mg deficiency tolerance in C. sinensis may be attributed to the following aspects: (a) enhanced microtubule-based movement and cell cycle regulation; (b) elevated signal transduction in response to biotic and abiotic stimuli; (c) alteration of biological processes by tightly controlling phosphorylation especially protein phosphorylation; (d) down-regulation of light harvesting and photosynthesis due to the accumulation of carbohydrates; (e) up-regulation of cell wall remodeling and antioxidant system. Our results provide a comprehensive insight into the transcriptomic profile of key components involved in the Mg deficiency tolerance in C. sinensis and enrich our understanding of the molecular mechanisms by which plants adapted to a Mg deficient condition.

[Analysis of radiation workers health status in a city]

Objective: To investigate the health status of radiation workers in a city and provide evidence for the health management of radiation workers. Methods: To investigate the health status of radiation workers in a city and provide evidence for the health management of radiation workers. Results: The majority of radiation workers are engaged in diagnostic radiology, male is more than female. The abnormal rate of micronuclear (0.59‰) and chromosome aberration (0.47%) was highest in nuclear medicine workers. The abnormal rate of micronuclear and chromosome aberration was similar with interventional and diagnostic radiology. Expect for micronuclear (χ(2)=32.945, P<0.01) and chromosome aberration (χ(2)=75149.737, P<0.01) , other radiation sensitive indicators have no difference. The abnormal rate of thyroid function (18.8%) (χ(2)=12.084, P<0.01) , micronuclear (0.25‰) (χ(2)=57.359, P<0.01) , chromosome aberration (0.08%) (χ(2)=17.209, P<0.01) in group whose service length exceeding 20 years was higher than other service length groups. There is no statistical difference in other radiation sensitive indicators among different service length group. Conclusion: Long-term low doses of ionizing radiation could affect radiation worker's health, expecially radiation workers engaged in nuclear medicine and radiotherapy. We must pay attention to occupaitonal health care and management to ensure radiation worker's health.

Responses of reactive oxygen species and methylglyoxal metabolisms to magnesium-deficiency differ greatly among the roots, upper and lower leaves of Citrus sinensis

BACKGROUND

Magnesium (Mg)-deficiency is one of the most prevalent physiological disorders causing a reduction in Citrus yield and quality. 'Xuegan' (Citrus sinensis) seedlings were irrigated for 16 weeks with nutrient solution containing 2 mM (Mg-sufficiency) or 0 mM (Mg-deficiency) Mg(NO3)2. Thereafter, we investigated the Mg-deficient effects on gas exchange and chlorophyll a fluorescence in the upper and lower leaves, and Mg, reactive oxygen species (ROS) and methylglyoxal (MG) metabolisms in the roots, lower and upper leaves. The specific objectives were to corroborate the hypothesis that the responses of ROS and MG metabolisms to Mg-deficiency were greater in the lower leaves than those in the upper leaves, and different between the leaves and roots.

RESULTS

Mg level was higher in the Mg-deficient upper leaves than that in the Mg-deficient lower leaves. This might be responsible for the Mg-deficiency-induced larger alterations of all the measured parameters in the lower leaves than those in the upper leaves, but they showed similar change patterns between the Mg-deficient lower and upper leaves. Accordingly, Mg-deficiency increased greatly their differences between the lower and upper leaves. Most of parameters involved in ROS and MG metabolisms had similar variation trends and degrees between the Mg-deficient lower leaves and roots, but several parameters (namely glutathione S-transferase, sulfite reductase, ascorbate and dehydroascorbate) displayed the opposite variation trends. Obviously, differences existed in the Mg-deficiency-induced alterations of ROS and MG metabolisms between the lower leaves and roots. Although the activities of most antioxidant and sulfur metabolism-related enzymes and glyoxalase I and the level of reduced glutathione in the Mg-deficient leaves and roots and the level of ascorbate in the leaves were kept in higher levels, the levels of malonaldehyde and MG and/or electrolyte leakage were increased in the Mg-deficient lower and upper leaves and roots, especially in the Mg-deficient lower leaves and roots.

CONCLUSIONS

The ROS and MG detoxification systems as a whole did not provide sufficient detoxification capacity to prevent the Mg-deficiency-induced production and accumulation of ROS and MG, thus leading to lipid peroxidation and the loss of plasma membrane integrity, especially in the lower leaves and roots.

Proteome profile analysis of boron-induced alleviation of aluminum-toxicity in Citrus grandis roots

Aluminum (Al)-toxicity and boron (B)-deficiency are two major factors limiting crop production in tropical and subtropical areas. Elevating B supply can alleviate the Al-induced inhibition of growth in Citrus grandis. Seedlings of C. grandis were irrigated for 18 weeks with nutrient solutions containing two B levels (2.5 and 20 μM H₃BO₃) and two Al levels (0 and 1.2 mM AlCl₃·6H₂O). By using 2-dimensional electrophoresis (2-DE) based MALDI-TOF/TOF-MS method, this study successfully identified and quantified sixty-one differentially abundant proteins in Citrus roots in response to B-Al interactions. The mechanisms underlying the B-induced alleviation of Al-toxicity unveiled by 2-DE technique could be summarized as follows: a) remodeling of cell wall by reducing the synthesis of lignin (sugar ATP Binding Cassette (ABC) transporter ATPase and cinnamyl alcohol dehydrogenase) and increasing the modification of cell wall (UDP-forming); b) enhancing the abundances of proteasomes and turnover of dysfunctional proteins (proteasome or protease); c) increasing the abundance of stress response proteins, such as alcohol dehydrogenase, S-adenosylmethionine synthetase (SAMS) and glycosyl hydrolase; d) reinforcing cellular biological regulation and signal transduction (calreticulin-1). For the first time, some proteins, such as cell division protein 48 (CDC48), calreticulin and phospholipase, which might be involved in the downstream signaling of Al in Citrus plants, were successfully identified.

Aluminum effects on photosynthesis, reactive oxygen species and methylglyoxal detoxification in two Citrus species differing in aluminum tolerance

Citrus are mainly grown in low pH soils with high active aluminum (Al). 'Xuegan' (Citrus sinensis (L.) Osbeck) and 'Shatian pummelo' (Citrus grandis (L.) Osbeck) seedlings were fertilized for 18 weeks with nutrient solution containing either 0 mM (control) or 1 mM (Al toxicity) AlCl3·6H2O. Aluminum induced decreases of biomass, leaf photosynthesis, relative water content and total soluble protein levels, and increases of methylglyoxal levels only occurred in C. grandis roots and leaves. Besides, the Al-induced decreases of pigments and alterations of chlorophyll a fluorescence transients and fluorescence parameters were greater in C. grandis leaves than those in C. sinensis leaves. Aluminum-treated C. grandis had higher stem and leaf Al levels and similar root Al levels relative to Al-treated C. sinensis, but lower Al distribution in roots and Al uptake per plant. Aluminum toxicity decreased nitrogen, phosphorus, potassium, calcium, magnesium and sulfur uptake per plant in C. grandis and C. sinensis seedlings, with the exception of Al-treated C. sinensis seedlings exhibiting increased sulfur uptake per plant and unaltered magnesium uptake per plant. Under Al-stress, macroelement uptake per plant was higher in C. sinensis than that in C. grandis. Aluminum toxicity decreased the ratios of reduced glutathione/(reduced + oxidized glutathione) and of ascorbate/(ascorbate + dehydroascorbate) only in C. grandis roots and leaves. The activities of most antioxidant enzymes, sulfur metabolism-related enzymes and glyoxalases and the levels of S-containing compounds were higher in Al-treated C. sinensis roots and leaves than those in Al-treated C. grandis ones. Thus, C. sinensis displayed higher Al tolerance than C. grandis did. The higher Al tolerance of C. sinensis might involve: (i) more Al accumulation in roots and less transport of Al from roots to shoots; (ii) efficient maintenance of nutrient homeostasis; and (iii) efficient maintenance of redox homeostasis via detoxification systems of reactive oxygen species and methylglyoxal.

Low pH-responsive proteins revealed by a 2-DE based MS approach and related physiological responses in Citrus leaves

BACKGROUND

Rare data are available on the molecular responses of higher plants to low pH. Seedlings of 'Sour pummelo' (Citrus grandis) and 'Xuegan' (Citrus sinensis) were treated daily with nutrient solution at a pH of 2.5, 3, or 6 (control) for nine months. Thereafter, we first used 2-dimensional electrophoresis (2-DE) to investigate low pH-responsive proteins in Citrus leaves. Meanwhile, we examined low pH-effects on leaf gas exchange, carbohydrates, ascorbate, dehydroascorbate and malondialdehyde. The objectives were to understand the adaptive mechanisms of Citrus to low pH and to identify the possible candidate proteins for low pH-tolerance.

RESULTS

Our results demonstrated that Citrus were tolerant to low pH, with a slightly higher low pH-tolerance in the C. sinensis than in the C. grandis. Using 2-DE, we identified more pH 2.5-responsive proteins than pH 3-responsive proteins in leaves. This paper discussed mainly on the pH 2.5-responsive proteins. pH 2.5 decreased the abundances of proteins involved in ribulose bisphosphate carboxylase/oxygenase activation, Calvin cycle, carbon fixation, chlorophyll biosynthesis and electron transport, hence lowering chlorophyll level, electron transport rate and photosynthesis. The higher oxidative damage in the pH 2.5-treated C. grandis leaves might be due to a combination of factors including higher production of reactive oxygen species, more proteins decreased in abundance involved in antioxidation and detoxification, and lower ascorbate level. Protein and amino acid metabolisms were less affected in the C. sinensis leaves than those in the C. grandis leaves when exposed to pH 2.5. The abundances of proteins related to jasmonic acid biosynthesis and signal transduction were increased and decreased in the pH 2.5-treated C. sinensis and C. grandis leaves, respectively.

CONCLUSIONS

This is the first report on low pH-responsive proteins in higher plants. Thus, our results provide some novel information on low pH-toxicity and -tolerance in higher plants.

Aluminum-responsive genes revealed by RNA-Seq and related physiological responses in leaves of two Citrus species with contrasting aluminum-tolerance

Little is known about the physiological and molecular responses of leaves to aluminum (Al)-toxicity. Seedlings of Al-intolerant Citrus grandis and Al-tolerant Citrus sinensis were supplied daily with nutrient solution containing 0 mM (control) and 1.0 mM (Al-toxicity) AlCl₃·6H₂O for 18 weeks. We found that Al-treatment only decreased CO₂ assimilation in C. grandis leaves, and that the Al-induced alterations of gene expression profiles were less in C. sinensis leaves than those in C. grandis leaves, indicating that C. sinensis seedlings were more tolerant to Al-toxicity than C. grandis ones. Al concentration was similar between Al-treated C. sinensis and C. grandis roots, but it was higher in Al-treated C. grandis stems and leaves than that in Al-treated C. sinensis stems and leaves. Al-treated C. sinensis seedlings accumulated relatively more Al in roots and transported relatively little Al to shoots. This might be responsible for the higher Al-tolerance of C. sinensis. Further analysis showed that the following several aspects might account for the higher Al-tolerance of C. sinensis, including: (a) Al-treated C. sinensis leaves had higher capacity to maintain the homeostasis of energy and phosphate, the stability of lipid composition and the integrity of cell wall than did Al-treated C. grandis leaves; (b) Al-triggered production of reactive oxygen species (ROS) and the other cytotoxic compounds was less in Al-treated C. sinensis leaves than that in Al-treated C. grandis leaves, because Al-toxicity decreased CO₂ assimilation only in C. grandis leaves; accordingly, more upregulated genes involved in the detoxifications of ROS, aldehydes and methylglyoxal were identified in Al-treated C. grandis leaves; in addition, flavonoid concentration was increased only in Al-treated C. grandis leaves; (c) Al-treated C. sinensis leaves could keep a better balance between protein phosphorylation and dephosphorylation than did Al-treated C. grandis leaves; and (d) both the equilibrium of hormones and hormone-mediated signal transduction were greatly disrupted in Al-treated C. grandis leaves, but less altered in Al-treated C. sinensis leaves. Finally, we discussed the differences in Al-responsive genes between Citrus roots and leaves.

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36}  cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5  GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2  GeV/c^{2}.

Sulfur-Mediated-Alleviation of Aluminum-Toxicity in Citrus grandis Seedlings

Limited data are available on the sulfur (S)-mediated-alleviation of aluminum (Al)-toxicity in higher plants. Citrus grandis seedlings were irrigated for 18 weeks with 0.5 mM MgSO₄ or 0.5 mM MgSO₄ + 0.5 mM Na₂SO₄, and 0 (-Al) or 1 mM AlCl₃·6H₂O (+Al, Al-toxicity). Under Al-toxicity, S decreased the level of Al in leaves; increased the relative water content (RWC) of roots and leaves, the contents of phosphorus (P), calcium (Ca) and magnesium (Mg) per plant, the dry weights (DW) of roots and shoots, the ratios of root DW/shoot DW, and the Al-induced secretion of citrate from root; and alleviated the Al-induced inhibition of photosynthesis via mitigating the Al-induced decrease of electron transport capacity resulting from the impaired photosynthetic electron transport chain. In addition to decreasing the Al-stimulated H₂O₂ production, the S-induced upregulation of both S metabolism-related enzymes and antioxidant enzymes also contributed to the S-mediated-alleviation of oxidative damage in Al-treated roots and leaves. Decreased transport of Al from roots to shoots and relatively little accumulation of Al in leaves, and increased leaf and root RWC and P, Ca, and Mg contents per plant might also play a role in the S-mediated-alleviation of Al-toxicity.

Long-term manganese-toxicity-induced alterations of physiology and leaf protein profiles in two Citrus species differing in manganese-tolerance

Manganese (Mn)-intolerant 'Sour pummelo' (Citrus grandis) and Mn-tolerant 'Xuegan' (Citrus sinensis) seedlings were irrigated for 17 weeks with 2 (control) or 600μM (Mn-toxicity or -excess) MnSO₄. C. sinensis had higher Mn-tolerance than C. grandis, as indicated by the higher photosynthesis rates in Mn-excess C. sinensis leaves. Under Mn-toxicity, Mn levels were similar between C. sinensis and C. grandis roots, but lower in C. sinensis leaves than in C. grandis leaves. This might be responsible for C. sinensis Mn-tolerance. Using two-dimensional electrophoresis, we identified more differentially abundant proteins (DAPs) in Mn-excess C. grandis than in Mn-excess C. sinensis leaves, which agrees with the higher Mn levels in Mn-excess C. grandis leaves. DAPs were mainly related to carbohydrate and energy metabolism, stress response, and protein and amino acid metabolism. DAPs involved in the cytoskeleton and signal transduction were found only in Mn-excess C. grandis leaves. We isolated more photosynthesis-related proteins with decreased abundances in Mn-excess C. grandis leaves than in Mn-excess C. sinensis leaves, which might account for the larger decrease in photosynthesis rates in C. grandis leaves. The abundances of proteins involved in reactive oxygen species (ROS) scavenging and photorespiration were increased in Mn-excess C. grandis leaves, while only proteins involved in ROS detoxification were increased in Mn-excess C. sinensis leaves. This agrees with the increased requirement for dissipating the excess absorbed light energy, which was higher in Mn-excess C. grandis leaves than Mn-excess C. sinensis leaves because Mn-toxicity inhibited photosynthesis to a greater degree in C. grandis leaves.

Magnesium-deficiency-induced alterations of gas exchange, major metabolites and key enzymes differ among roots, and lower and upper leaves of Citrus sinensis seedlings

Magnesium (Mg)-deficiency is a widespread problem adversely affecting the quality and yield of crops, including citrus. 'Xuegan' [Citrus sinensis (L.) Osbeck] seedlings were irrigated every other day with nutrient solution at an Mg concentration of 0 mM (Mg-deficiency) or 1 mM (Mg-sufficiency) for 16 weeks. Thereafter, biomass, leaf mass per area, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), pigments in the upper and lower leaves, Mg, gas exchange, organic acids, nonstructural carbohydrates, total soluble proteins, amino acids, phenolics and anthocyanins, and key enzymes related to organic acid, amino acid and phenolic metabolisms in the roots, and upper and lower leaves were assayed in order to test the hypothesis that Mg-deficiency-induced alterations of gas exchange, major metabolites and key enzymes may differ among the roots, and upper and lower leaves. Magnesium-deficiency affected the most measured parameters more in the lower than in the upper leaves except for the nonstructural carbohydrates, but the variation trends were similar between the two. Despite increased accumulation of nonstructural carbohydrates, the lower CO2 assimilation in the Mg-deficient leaves was not caused by the feedback inhibition mechanism via sugar accumulation. Both dark respiration and organic acid metabolism were elevated in the Mg-deficient lower leaves to 'consume' the excess carbohydrates, and inhibited in the Mg-deficient roots with less accumulation of nonstructural carbohydrates to keep the balance of net carbon. More total phenolics and fewer anthocyanins were accumulated in the Mg-deficient lower leaves, whereas the accumulation of both total phenolics and anthocyanins was reduced in the Mg-deficient roots. Interestingly, amino acid biosynthesis was repressed in the Mg-deficient roots and lower leaves, thus lowering the level of total free amino acids in these roots and leaves. To conclude, great differences existed in the Mg-deficiency-induced alterations of gas exchange, major metabolites and key enzymes among the roots, and upper and lower leaves.

MicroRNA-mediated responses to long-term magnesium-deficiency in Citrus sinensis roots revealed by Illumina sequencing

Background

Magnesium (Mg)-deficiency occurs most frequently in strongly acidic, sandy soils. Citrus are grown mainly on acidic and strong acidic soils. Mg-deficiency causes poor fruit quality and low fruit yield in some Citrus orchards. For the first time, we investigated Mg-deficiency-responsive miRNAs in ‘Xuegan’ (Citrus sinensis) roots using Illumina sequencing in order to obtain some miRNAs presumably responsible for Citrus Mg-deficiency tolerance.

Results

We obtained 101 (69) miRNAs with increased (decreased) expression from Mg-starved roots. Our results suggested that the adaptation of Citrus roots to Mg-deficiency was related to the several aspects: (a) inhibiting root respiration and related gene expression via inducing miR158 and miR2919; (b) enhancing antioxidant system by down-regulating related miRNAs (miR780, miR6190, miR1044, miR5261 and miR1151) and the adaptation to low-phosphorus (miR6190); (c) activating transport-related genes by altering the expression of miR6190, miR6485, miR1044, miR5029 and miR3437; (d) elevating protein ubiquitination due to decreased expression levels of miR1044, miR5261, miR1151 and miR5029; (e) maintaining root growth by regulating miR5261, miR6485 and miR158 expression; and (f) triggering DNA repair (transcription regulation) by regulating miR5176 and miR6485 (miR6028, miR6190, miR6485, miR5621, miR160 and miR7708) expression. Mg-deficiency-responsive miRNAs involved in root signal transduction also had functions in Citrus Mg-deficiency tolerance.

Conclusions

We obtained several novel Mg-deficiency-responsive miRNAs (i.e., miR5261, miR158, miR6190, miR6485, miR1151 and miR1044) possibly contributing to Mg-deficiency tolerance. These results revealed some novel clues on the miRNA-mediated adaptation to nutrient deficiencies in higher plants.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3999-5) contains supplementary material, which is available to authorized users.