Transcriptomics Reveals the ERF2-bHLH2-CML5 Module Responses to H2S and ROS in Postharvest Calcium Deficiency Apples.

Calcium deficiency usually causes accelerated quality deterioration in postharvest fruit, whereas the underlining mechanism is still unclear. Here, we report that calcium deficiency induced the development of bitter pit on the surface of apple peels compared with the healthy appearance in control apples during postharvest storage. Physiological analysis indicates that calcium-deficient peels contained higher levels of superoxide anion (O2•-), malondialdehyde (MDA), total phenol, flavonoid contents and polyphenol oxidase (PPO) activity, and reduced calcium, H2S production, anthocyanin, soluble protein content, and peroxidase (POD) activity compared with those in calcium-sufficient peels. The principal component analysis (PCA) results show that calcium content, ROS, and H2S production were the main factors between calcium-deficient and calcium-sufficient apple peels. Transcriptome data indicated that four calmodulin-like proteins (CMLs), seven AP2/ERFs, and three bHLHs transcripts were significantly differentially expressed in calcium-deficient apple peels. RT-qPCR and correlation analyses further revealed that CML5 expression was significantly positively correlated with the expression of ERF2/17, bHLH2, and H2S production related genes. In addition, transcriptional co-activation of CML5 by ERF2 and bHLH2 was demonstrated by apple transient expression assays and dual-luciferase reporter system experiments. Therefore, these findings provide a basis for studying the molecular mechanism of postharvest quality decline in calcium-deficient apples and the potential interaction between Ca2+ and endogenous H2S.

Activin A induces growth arrest through a SMAD- dependent pathway in hepatic progenitor cells.

BACKGROUND: Activin A, an important member of transforming growth factor-ß superfamily, is reported to inhibit proliferation of mature hepatocyte. However, the effect of activin A on growth of hepatic progenitor cells is not fully understood. To that end, we attempted to evaluate the potential role of activin A in the regulation of hepatic progenitor cell proliferation. RESULTS: Using the 2-acetaminofluorene/partial hepatectomy model, activin A expression decreased immediately after partial hepatectomy and then increased from the 9th to 15th day post surgery, which is associated with the attenuation of oval cell proliferation. Activin A inhibited oval cell line LE6 growth via activating the SMAD signaling pathway, which manifested as the phosphorylation of SMAD2/3, the inhibition of Rb phosphorylation, the suppression of cyclinD1 and cyclinE, and the promotion of p21WAF1/Cip1 and p15INK4B expression. Treatment with activin A antagonist follistatin or blocking SMAD signaling could diminish the anti-proliferative effect of activin A. By contrast, inhibition of the MAPK pathway did not contribute to this effect. Antagonizing activin A activity by follistatin administration enhanced oval cell proliferation in the 2-acetylaminofluorene/partial hepatectomy model. CONCLUSION: Activin A, acting through the SMAD pathway, negatively regulates the proliferation of hepatic progenitor cells.

Using protein granularity to extract the protein sequence features.

The feature extraction of protein sequences is a challenging problem. It might need a lot of theoretical and practical knowledge from many fields. The difficulty would increase when investigators extract the features solely from protein sequences. In this paper, we present a method of protein granularity. The concepts of protein granularity, granularity order, granularity bound, granularity limit, and granularity increment are given respectively. The protein granularity can dig out the useful information solely from protein sequences. We provide an approach to construct the feature vectors. The feature vectors include the amino acid composition information, the sequence-order information, the same amino acid 'neighbor' information, and the sequence length information. Hence, the feature vectors can better represent protein sequences. Our feature extraction method does obviously consider the protein sequence length effects. An experiment of the protein structure class prediction was carried out. The prediction achieved 96.6% overall accuracy, and the success rate for each subset is all-α 92.3%, all-ß 100%, α/ß 100%, α+ß 93.5%, respectively. The last three success rates for subsets are equal to the best success rates in the published literatures. The overall accuracy of PG-SVM prediction is the second best result only having one protein prediction error difference with the first best result. The theoretical and experimental results demonstrate the application of protein granularity succeeds in the feature extraction of protein sequences.

HSCs play a distinct role in different phases of oval cell-mediated liver regeneration.

Hepatic stem cell niche plays an important role in hepatic oval cell-mediated liver regeneration. As a component of hepatic stem cell niche, the role of hepatic stellate cells (HSCs) in oval cell proliferation needs further studies. In the present study, we isolated HSCs from rats at indicated time point after partial hepatectomy (PH) in 2-acetylaminofluorene/PH oval cell proliferation model. Conditional medium (CM) from HSCs were collected to detect their effects on proliferation and the mitogen-activated protein kinase pathway activation of two oval cell lines. We found that CM collected from HSCs at early phase of liver regeneration (4 and 9 days group) contained high levels of hepatocyte growth factor (HGF) and stimulated oval cell proliferation via extracellular signal-regulated kinase and p38 pathway. CM collected from HSCs at terminal phase of liver regeneration (12 and 15 days group) contained high levels of transforming growth factor (TGF)-ß1, which suppressed DNA synthesis of oval cells. The shift between these two distinct effects depended on the balance between HGF and TGF-ß1 secreted by HSCs. Our study demonstrated that HSCs acted as a positive regulator at the early phase and a negative regulator at the terminal phase of the oval cell-mediated liver regeneration.

[Expression of tumor necrosis factor-alpha and caspase-3 protein in monocytes adjacent to the invaded Echinococcus multilocularis in liver].

OBJECTIVE: To investigate the expression and its significance of tumor necrosis factor-alpha (TNF-alpha) and caspase-3 protein in monocytes adjacent to the invaded Echinococcus multilocularis in liver. METHODS: 40 female Kunming mice were randomly divided into experimental group (n=20) and sham operation (control) group (n=20). Mice in experimental group were infected with 20% E. multilocularis suspension (0.1 ml per mouse) through abdominal opening injection in liver and the mice in control group were injected with equal physiological saline. The mice were sacrificed at 6 months post-infection for observing the growth and metastasis of E. multilocularis. Pathological changes were observed by HE staining. The expression of TNF-alpha and caspase-3 protein in hydatid cyst and metastasis tissue were detected by immunohistochemistry staining and the apoptosis of the monocytes was measured by TUNEL. RESULTS: After 6 months post-infection, E. multilocularis were spread over the liver of the mice in experimental group. Metastasis rate of lymph nodes was 45.0% (9/20). Infiltration of monocytes was observed around E. multilocularis in liver and lymph nodes with metastasis by HE staining. Immunohistochemistry showed that the positive expression rate of TNF-alpha and caspase-3 protein in monocytes was 100% and 100%, and 95% and 100% respectively around the cyst in experimental group, while the expression rate was only 5% and 0 respectively in the liver of the control mice (P<0.01). The monocytes showed significant apoptosis by TUNEL in experimental group with a positive expression rate of 100%, with a significant difference between experiment group and the control (P<0.01). CONCLUSION: In the process of alveolar Echinococcus infection, the high expression of TNF-alpha protein might be associated with the apoptosis of monocytes, which may inhibit the host immunological function.

Analysis of mechanisms of Shenhuang Granule in treating severe COVID-19 based on network pharmacology and molecular docking.

OBJECTIVE: Severe cases of coronavirus disease 2019 (COVID-19) are expected to have a worse prognosis than mild cases. Shenhuang Granule (SHG) has been shown to be a safe and effective treatment for severe COVID-19 in a previous randomized clinical trial, but the active chemical constituents and underlying mechanisms of action remain unknown. The goal of this study is to explore the chemical basis and mechanisms of SHG in the treatment of severe COVID-19, using network pharmacology. METHODS: Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was employed to screen chemical constituents of SHG. Putative therapeutic targets were predicted by searching traditional Chinese medicine system pharmacology database and analysis platform, SwissTargetPrediction, and Gene Expression Omnibus (GEO) databases. The target protein-protein interaction network and enrichment analysis were performed to investigate the hub genes and presumptive mechanisms. Molecular docking and molecular dynamics simulations were used to verify the stability and interaction between the key chemical constituents of SHG and COVID-19 protein targets. RESULTS: Forty-five chemical constituents of SHG were identified along with 131 corresponding therapeutic targets, including hub genes such as HSP90AA1, MMP9, CXCL8, PTGS2, IFNG, DNMT1, TYMS, MDM2, HDAC3 and ABCB1. Functional enrichment analysis indicated that SHG mainly acted on the neuroactive ligand-receptor interaction, calcium signaling pathway and cAMP signaling pathway. Molecular docking showed that the key constituents had a good affinity with the severe acute respiratory syndrome coronavirus 2 protein targets. Molecular dynamics simulations indicated that ginsenoside Rg4 formed a stable protein-ligand complex with helicase. CONCLUSION: Multiple components of SHG regulated multiple targets to inhibit virus invasion and cytokine storm through several signaling pathways; this provides a scientific basis for clinical applications and further experiments.

[The correlation between osteopontin and metastasis of hepatic Echinococcus multilocularis infection].

OBJECTIVE: To investigate the expression and distribution of osteopontin (OPN) in Echinococcus multilocularis cyst, and explore the role of OPN in the metastasis of hepatic E. multilocularis infection. METHODS: Forty gerbils were infected with 20% E. multilocularis suspension (0.1 ml per gerbil) through abdominal opening injection in liver. Gerbils were sacrificed at 100 days postinfection for observing the growth and metastasis of hepatic echinococcus cyst. The liver, hepatic echinococcus cyst and metastasis tissue were observed on HE stain; the expression of OPN were measured by immunohistochemistry staining (SP method). RESULTS: E. multilocularis were spread over the liver and abdominal cavity. Expression of OPN was found at different degree in echinococcus cysts. The positive expression rate of OPN in echinococcus cysts was 70% (28/40). OPN was mainly distributed in the germinal layer, inflammatory cells and some liver cells. 60% (24/40) occurred thoracic lymph node metastases. The OPN expression rate in hepatic echinococcus cysts with thoracic lymph node metastases (83%, 20/24) was significantly higher than that of hepatic echinococcus cysts without thoracic lymph node metastases (50%, 8/16) (P < 0.05). The positive expression of OPN in lymph node metastases (92%, 22/24) was higher than that of hepatic echinococcus cyst (70%, 28/40) (P < 0.05). CONCLUSION: Osteopontin mainly distributes in the germinal layer of hepatic echinococcus cyst and inflammatory cells, which might be involved in metastasis of hepatic E. multilocularis infection.

[Inhibition of invasive growth and metastasis of hepatic alveolar echinococcosis by anti-osteopontin antibody].

OBJECTIVE: To observe the inhibitive effect on invasive growth and metastasis of Echinococcus multilocularis by exogenous anti-osteopontin (OPN) antibody. METHODS: 180 gerbils were infected with 20% E. multilocularis suspension (approximately 400 protoscoleces in 0.1 ml per gerbil) through abdominal opening injection in liver, and then divided into model group, experiment group and control group. Experiment group and control group each with 60 gerbils were injected via the tail vein with 0.15 ml of anti-OPN antibody (1:32) and rabbit serum, respectively. All gerbils in the two groups received injections, with 2-day interval for the first seven injections, and then at 7-day interval for the remaining injections. Model group were without any treatment. The three groups were subdivided into six groups each with 10 gerbils. The gerbils from each group were sacrificed on day 1, 20, 40, 60, 80, and 100 after infection, respectively. Hepatic echinococcus cyst and metastasis tissue were observed. The expression of OPN was measured by immunohistochemistry staining (SP method). Serum samples were collected at 100 d post-infection, and the content of OPN in sera was measured by ELISA. RESULTS: There were no significant difference in cyst weight and metastatic rate of thoracic lymph node among the three groups at 1, 20, 40, 60, and 80d post-infection (P > 0.05), while at 100 d postinfection, cyst weight and metastatic rate of thoracic lymph node in experiment group [(7.28 +/- 0.38) g, 20%] were lower than that of control group [(9.70 +/- 0.61) g, 70%] and model group [(932 +/- 0.73) g, 70%] (P < ). Expression of OPN was found at different levels in echinococcus cysts. OPN was located in the cytoplasm, and mainly distributed in the germinal layer. The OPN positive expression levels were not significantly different between experiment group and other groups on day 1, 20, 40, 60, and 80 afer infection ( >0 . 05). At 100d post-infection, OPN positive expression rate and serum OPN content in experimental group [20% and (30.90 +/- 2.25) ng/.l micro respectively] was lower than that of control group [80% and (41.03.2 +/- 76) nWng/micro and model group [80% and (42.39 +/- 2.85) nWng/micro (PdL < 0.). CONCLUSION: Anti-osteopontin antibody can reduce OPN concentration in hepatic echinococcus cyst and serum, and inhibit the invasive growth and metastasis of E. multilocularis.

[Carbonized Apple Branches Decrease the Accumulation and Damage of Cadmium on Apple Rootstock by Reducing DTPA-Cd in Soil].

To explore the effects of carbonized apple branches on cadmium(Cd) accumulation and its damage to apple rootstock, the rootstocks of apple(Malus hupehensis Rehd.) in pots containing soil together with 0.5% and 1%(ω) carbonized apple branches were irrigated by a nutrient solution containing CdSO4. The content of DTPA-Cd(cadmium extracted by diethylenetriamine pentaacetic acid) in the potting soil, and the accumulation of Cd in the roots, stems, and leaves of apple rootstocks, were subsequently monitored. The activities of antioxidant enzymes in roots and leaves, root cell death, and the net photosynthesis rate were further analyzed. The results showed that the concentration of DTPA-Cd in the potting soil with carbonized apple branches was significantly lower than that without carbonized apple branches(Cd-only). Compared with the Cd-only treatment, the concentration of DTPA-Cd in the potting soil decreased by 17.50% and 25.55% in the treatment with 0.5% and 1%(ω) carbonized apple branches for 12 days. The Cd accumulation in roots, stems, and leaves; the accumulations of superoxide anions(·O2-), hydrogen peroxide(H2O2), and malondialdehyde(MDA) in roots and leaves; and the amount of cell death in the roots of apple rootstock treated by carbonized apple branches were significantly lower compared to the Cd-only treatment. However, the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT) in the roots and leaves, and the net photosynthesis rate of apple rootstock treated by carbonized apple branches, were significantly higher than under the Cd-only treatment. Compared with the Cd-only treatment, Cd accumulation in roots decreased by 29.49% and 37.18% in the treatment with 0.5% and 1%(ω) carbonized apple branches for 12 days, and the amount of cell death decreased by 22.73% and 29.09%, respectively. Our results show that carbonized apple branches reduce the uptake and accumulation of Cd in apple rootstock by reducing the content of DTPA-Cd in the soil, thereby alleviating the damaging effect of Cd on cells and photosynthesis. Moreover, the use of 1%(ω) carbonized apple branches was more effective than 0.5%(ω).

Hydrogen Sulfide Alleviates Alkaline Salt Stress by Regulating the Expression of MicroRNAs in Malus hupehensis Rehd. Roots.

Malus hupehensis Rehd. var. pingyiensis Jiang (Pingyi Tiancha, PYTC) is an excellent apple rootstock and ornamental tree, but its tolerance to salt stress is weak. Our previous study showed that hydrogen sulfide (H2S) could alleviate damage in M. hupehensis roots under alkaline salt stress. However, the molecular mechanism of H2S mitigation alkaline salt remains to be elucidated. MicroRNAs (miRNAs) play important regulatory roles in plant response to salt stress. Whether miRNAs are involved in the mitigation of alkaline salt stress mediated by H2S remains unclear. In the present study, through the expression analysis of miRNAs and target gene response to H2S and alkaline salt stress in M. hupehensis roots, 115 known miRNAs (belonging to 37 miRNA families) and 15 predicted novel miRNAs were identified. In addition, we identified and analyzed 175 miRNA target genes. We certified the expression levels of 15 miRNAs and nine corresponding target genes by real-time quantitative PCR (qRT-PCR). Interestingly, H2S pretreatment could specifically induce the downregulation of mhp-miR408a expression, and upregulated mhp-miR477a and mhp-miR827. Moreover, root architecture was improved by regulating the expression of mhp-miR159c and mhp-miR169 and their target genes. These results suggest that the miRNA-mediated regulatory network participates in the process of H2S-mitigated alkaline salt stress in M. hupehensis roots. This study provides a further understanding of miRNA regulation in the H2S mitigation of alkaline salt stress in M. hupehensis roots.

[Effect of the liposome albendazole and Huai-Er fungus extract on hepatic infection of Echinococcus granulosus in mice].

OBJECTIVE: To explore the effect of Huai-Er fungus extract (HEF) and liposome albendazole (L-ABZ) on the hepatic infection of Echinococcus granulosus (Eg) in mice, and understand the influence of improved host immunity on postoperative recurrence. METHODS: Female Kunming mice were immune by intraperitoneal injection Eg cyst fluid from sheep, IgG positive mice were divided into drug treatment groups (A, B and C) and control group (D). Mice in group A were administered by gavage with single L-ABZ (75 mg/kg), group B with single HEF (15,000 mg/kg), and group C with combination therapy (L-ABZ 75 mg/kg plus HEF 15,000 mg/kg), once every two days for one week. The protoscoleces were treated with balanced solution for 20 minute and inoculated in the liver by open abdomen of the anesthetized mice. Imitating to an "open sub-adventitial total exocystectomy", protoscoleces outside the cyst led to a reinfection. 72 hours later, groups A, B and C were re-treated for a month. Mice in group D were given with distilled water (0.3 ml per mouse). Group E was set as blank control (n=8). Another 120 IgG positive mice were divided as groups F, G, H and I, and treated in parallel with the groups A, B, C and D respectively; these mice were inoculated with protoscoleces which were treated in advance with 75% alcohol, 20% hypertonic saline, L-ABZ and PBS for 20 min respectively. In 3 months after infection, all the mice were sacrificed to evaluate the efficacy, which covered infection rate, pathological change, spleen index, level of IgG and IgE, CD4+ and CD8+ cells. RESULTS: The recurrence rate in group C (5.7%) was lower than that of groups A (17.1%) and B (24.2%), with hydatid cysts in white colour and nodular, showing degeneration of the germinal and laminated layers. Groups A, B and C showed lower spleen index (A: 3.84+/-0.86, B: 3.95+/-1.01, and C: 3.27+/-0.52), and lower IgE level (A: 0.06+/-0.08, B: 0.07+/-0.08 and C: 0.03+/-0.03) than group D (5.46+/-0.52 and 0.20+/-0.02, respectively) (P<0.05), especially in group C; and also lowerCD8+ in groups A (16.61+/-3.89), B (18.18+/-3.90) and C (15.38+/-2.63) than group D (32.90+/-4.71) (P<0.05), but higher CD4+/CD8+ in groups A (3.21+/-0.70), B (3.05+/-0.66) and C (3.53+/-0.57) than group D (1.57+/-0.26) (P<0.05), especially in group C. The infection rate of mice in group F, Gand H was 0, 0 and 23.1% respectively, and that of group I, 31.2% (P<0.01). CONCLUSION: The combination of HEF and L-ABZ considerably improves the immunity of the hosts and HEF may have a synergetic action to L-ABZ in reducing the recurrence of "sub-adventitial total exocystectomy". 75% alcohol and 20% hypertonic saline show better effect of inactivating protoscoleces than L-ABZ in surgical operation.

[Physiological function of arginine and its metabolites in plants].

L-arginine is an important and unique amino acid in plants. It serves not only as an important nitrogen reserve and recycling, but also as a precursor of the biosynthesis of polyamines, nitric oxide and so on. Polyamines and nitric oxide are important messengers involved in almost all physiological and biochemical processes, growth & development, and adaptation of plants to stress. Arginine decarboxylase, arginase and nitric oxide synthase are the key enzymes in L-arginine catabolism, in which polyamines are formed through ADC or arginase-ODC pathway while nitric oxide is formed through the NOS pathway. The relative activity of these three enzymes can control the direction of arginine metabolism. Arginine content keeps higher level in roots during overwinter period. The arginine metabolism plays important role in perception and adaptation of plant to environmental disturbances.

[Observation on the ultrastructure of liver cells around hydatid cyst].

Liver tissues around hydatid from 8 patients with cystic echinococcosis were observed by transmission electron microscopy, normal hepatic tissues of 6 cases were used as control. The results demonstrated predominant atrophy and necrosis of hepatocytes. These changes seem to be the major hepatic lesion in cystic echinococcosis.

Inhibition of CDH17 gene expression via RNA interference reduces proliferation and apoptosis of human MKN28 gastric cancer cells.

Gastric cancer is the fourth most common type of cancer and the second cause of cancer­related mortalities worldwide despite the use of multimodal therapy. Cadherins are transmembrane glycoproteins that are involved in tumorigenesis. CDH17 has been found to be over­expressed in gastric cancer and its overexpression was associated with lymph node metastasis and tumor­node­metastasis stage of the patients, yet the exact role and molecular mechanism of CDH17 in gastric cancer have not been determined. Using a lentiviral system as a delivery mediator of RNA interference, we found that inhibition of CDH17 can lead to reduce proliferation and increase apoptosis of gastric cancer cell line MKN28 in vitro and significantly diminish their tumorigenicity in vivo. Our results of the present study suggest that CDH17 may be a promising candidate for the therapeutic targeting of gastric cancer.

[Effects of hydrogen sulfide on root architecture, leaf reactive oxygen and photosynthetic characteristics of Malus hupehensis under waterlogging.] / ç¡«åŒ–æ°¢å¯¹æ·¹æ°´å¹³é‚‘ç”œèŒ¶æ ¹ç³»å½¢æ€æž„åž‹ã€å¶ç‰‡æ´»æ€§æ°§å’Œå ‰åˆç‰¹æ€§çš„å½±å“.

The root architecture, leaf reactive oxygen species and photosynthetic characteristics of potted Malus hupehensis seedlings were investigated after 10 days of waterlogging under five concentrations of hydrogen sulfide (H2S) donor sodium hydrosulfide (NaSH, 0, 0.02, 0.05, 0.1, 0.2 mmol·L-1) and NaSH with scavenger hypotaurine (HT). The results showed that the root length, root surface area, root volume, root diameter, root top number, fractal dimension, first lateral roots and root activity all increased, the leaf superoxide anion (O2-·) accumulation and hydrogen pero-xide (H2O2) content both decreased, the leaf Pn, Tr, gs, WUE and CUE all raised, the plant height and biomass both increased when the 0.02-0.1 mmol·L-1 NaHS were added to the waterlogging environment. Adding 0.1 mmol·L-1 NaHS showed the best effects. All these parameters dropped back to the level of waterlogging alone when NaHS concentration was 0.2 mmol·L-1 or HT was added to the 0.1 mmol·L-1 NaHS solution. These suggested that applying an appropriate amount of H2S could effectively alleviate the inhibition of soil waterlogging on the root growth of M. hupehensis and relieve the effects of waterlogging stress on photosynthesis and plant growth by reducing the production of reactive oxygen species and increasing CUE.

[The effect of exogenous H2O2 on mitochondrial membrane permeability and cell nuclear DNA in roots of Malus hupehensis].

To investigate the changes in mitochondrial permeability transition, DNA degradation and cell death, seedling roots of Malus hupehensis Rehd. were treated directly with exogenous H(2)O(2). The results showed that mitochondrial permeability increased obviously by 0.024% (V/V) H(2)O(2) treatment for 30 min and increased continuously during the time of H(2)O(2) treatment (Fig.1). At the time of mitochondrial permeability increasing, mitochondrial membrane potential (Delta psi m) decreased (Fig.2). In addition, the ratio of Cyt c/a became lower (Fig.3) when mitochondrial permeability increased and Delta psi m decreased. DNA fragments were detected at the 60 min of H(2)O(2) treatment, the number of fragments increased after 60 min of H(2)O(2) treatment (Fig.4). Granular nuclei stained irregularly were evident in root slices stained by acridine orange (Fig.5). This indicates H(2)O(2) can induce programmed cell death by increasing mitochondrial permeability and decreasing Delta psi m in the root of Malus hupehensis Rehd.

[Analysis on the anatomic features of 47 cases of hepatic hydatidosis complicated with biliary fistula].

OBJECTIVE: To propose a criterion and its significance of clinical classification of hepatic hydatidosis complicated with biliary fistula. METHODS: 47 hepatic hydatidosis with biliary fistula cases who were given a subadventitial pericystectomy were observed from 2000 to 2005 in a retrospective study. The methods included observation of the different anatomic features of hepatic hydatidosis complicated with biliary fistula during the surgical operation and evaluation of the curative effect. RESULTS: All the 47 patients recuperated successfully and had no complication. Based on the anatomic features of hepatic hydatidosis complicated with biliary fistula, a criterion on clinical classification was proposed as three types: tangential, transfixional and terminal types. CONCLUSIONS: Hepatic hydatidosis complicated with biliary fistula can be classified as three types according to its anatomic features.

[Effects of different mulching materials on nitrate metabolism in soil of apple root-zone in summer and autumn.] / ä¸åŒè¦†ç›–ææ–™å¯¹å¤ç§‹è‹¹æžœæ ¹åŒºåœŸå£¤ç¡é ¸ç›ä»£è°¢çš„å½±å“.

This study explored the effects of mulching straw mat, agricultural carpet, transparent-plastic film and horticultural fabric on nitrification-denitrification, nitrate reductase (NR), nitrite reductase (NiR), ammonium, nitrate and nitrite nitrogen in root-zone soil grown with three-year old apple trees (Malus domestica cv. Starkrimson) during summer and autumn. Results showed that the four treatments decreased nitrification intensity in summer soil, NiR activity in summer-autumn soil and the variation coefficient of nitrification-denitrification intensity and NR in both summer and autumn soil. The treatments increased the denitrification intensity, NR activity, ammonium nitrogen contents in summer-autumn soil and ammonium nitrogen contents in autumn soil. Straw mat treatment increased denitrification intensity and nitrate nitrogen contents in both summer and autumn soil and decreased the activity of NR and NiR in summer soil. The coefficient of variation of nitrification-denitrification intensity and NR activity treated by mulching straw mat was lower than those in the other treatments in both summer and autumn soil. Agricultural carpet increased the NR and NiR activity in summer soil, the nitrate nitrogen contents in summer-autumn soil and the denitrification intensity in autumn soil and decreased denitrification intensity in summer soil. Transparent-plastic film increased the nitrite nitrogen contents in summer soil, the contents of nitrate nitrogen in summer-autumn soil, the nitrification intensity and NiR activity in autumn soil, and decreased nitrate nitrogen contents in summer soil. Horticultural fabric increased denitrification intensity in summer soil, nitrification intensity in summer-autumn and autumn soil and the nitrate nitrogen contents in autumn soil. The four mulching treatments all promoted plant growth. In the four mulching treatments, the new shoot and trunk thickening growth were more under straw mat and horticultural fabric treatments. The four mulching treatments had different effects on nitrate metabolism in summer and autumn soil, but they were able to stabilize the soil nitrate metabolism and transformation. Among the treatments, straw mat had the best stable effect.

Uptake and transport of calcium in plants.

Recently, research on Ca(2+) transport in plants has been focused on cellular and molecular level. But the uptake, transport and distribution are also very important for calcium to accomplish its function at whole plant level. There are many cells along the way of transport of Ca(2+) from root to shoot, and Ca(2+) passes either through the cytoplasm of cells linked by plasmodesmata (the symplast) or through the spaces between cells (the apoplast), which include Ca(2+) uptake by root cells, Ca(2+) transport from root cortex to and through the xylem, and then out of it into leaves or fruits. Ca(2+) channels, Ca(2+)/H(+) antiporter and Ca(2+)-ATPase play roles in the uptake and transport of Ca(2+) in root cells. To be transported from root surface to xylem, Ca(2+) needs to traverse endodermal cells and xylem parenchyma cells. Endodermal Casparian band, the main barrier for the apoplastic movement of ions into the stele, compels some Ca(2+) to enter root symplast through Ca(2+) channels in endodermal cells and then reach xylem parenchyma. Ca(2+)-ATPase may drive Ca(2+) into the stelar apoplast from xylem parenchyma. Some Ca(2+) effuses from endodermal cell and then get to xylem through apoplastic pathway. Ca(2+) is transported in plant xylem vessel in chelate form and the speed of water flow is the key factor Ca(2+) transport via xylem in trunk. There are both apoplastic and symplastic pathways of Ca(2+) transport in fruit or leaf tissue too.

MhNCED3 in Malus hupehensis Rehd. induces NO generation under osmotic stress by regulating ABA accumulation.

Abscisic acid (ABA) biosynthesis has been widely characterized in plants, whereas the effects of ABA biosynthesis on nitric oxide (NO) generation in osmotic stress are less well understood. In this study, Malus hupehensis Rehd. 9-cis-epoxycarotenoid dioxygenase gene (MhNCED3) which is the key gene in ABA biosynthesis was transformed into wild type (WT) and 129B08/nced3 mutant (AtNCED3 deficient), respectively, and two transgenic Arabidopsis lines were obtained. The transgenic Arabidopsis lines displayed higher endogenous ABA content, NO generation rate, AtNIA1 transcript level and nitrate reductase (NR) activity than WT and 129B08/nced3 mutant. Ectopic expression of MhNCED3 reduced the electrolyte leakage and relieved Arabidopsis damage caused by 20% PEG on the growth and development. The ABA content, NO generation rate, AtNIA1 expression and NR activity increased after 20% PEG treatment, importantly, their increases amplitude relative to that in control were higher in two transgenic lines. Additionally, during the treatment for the four genotype Arabidopsis, the time of ABA contents reaching the highest peak was earlier than the time of NO generation, AtNIA1 expression and NR activity reaching their highest peak. These results show that NCED gene indirectly induced endogenous NO generation in osmotic-stressed Arabidopsis partially contributing to the up-regulation of AtNIA1 expression and NR activity.