Auxiliary occlusal devices for IO scanning in a complete digital workflow of implant-supported crowns: a randomized controlled trial.

OBJECTIVES: To compare the crown accuracy and time efficiency of a complete digital workflow, utilizing an auxiliary occlusal device and IO scanning, with a conventional workflow, for multiple implant-supported single crowns. MATERIALS AND METHODS: 24 patients with two adjacent posterior implants were included. 12 patients were randomly assigned to digital workflow group, involving intra-oral scanning with an auxiliary occlusal device and manufacture of customized abutments and zirconia single crowns (test group). The other 12 were assigned to the conventional workflow (control group), involving conventional impression and CAD-CAM crowns based on stone casts. Crown scanning was done before and after clinical adjustment using an intraoral scanner. Two 3D digital models were overlapped to assess dimension changes. Chair-side and laboratory times for the entire workflow were recorded and a linear mixed model and Independent-sample t tests were used for the statistical analysis. RESULTS: The maximum occlusal deviation was 279.67 ± 112.17 µm and 479.59 ± 203.63 µm in the test and control group, respectively (p < 0.001). The sizes of the occlusion adjustment areas were 12.12 ± 10.51 mm2 and 25.12 ± 14.14 mm2 in the test and control groups, respectively (p = 0.013). The mean laboratory time was 46.08 ± 5.45 and 105.92 ± 6.10 min in the test and control groups, respectively (p < 0.001).The proximal contact adjustment and mean chair-side time showed no statistically significant difference between two groups. CONCLUSIONS: A digital workflow for two implants-supported single crowns using an auxiliary device required fewer occlusal crown adjustments, and less laboratory time compared to conventional workflow. CLINICAL RELEVANCE: The use of auxiliary occlusal devices in IOS enhances the accuracy of virtual maxillomandibular relationship in extended edentulous spans. Consequently, employing a digital workflow for multiple implants-supported crowns using IO scanning and an auxiliary occlusal device proves to be a feasible, accurate and efficient approach.

Crown adjustment and chairside efficiency of single-unit restorations fabricated from immediate and staged impressions using a digital workflow for posterior implants.

PURPOSE: This is a clinical study to compare immediate and staged impression methods in a complete digital workflow for single-unit implants in the posterior area. MATERIALS AND METHODS: Sixty patients requiring single-unit implant crowns were enrolled. Forty patients were assigned to the test group, immediate digital impression after implant surgery with crown delivery 4 months later. The remaining 20 patients were assigned to the control group, staged digital impressions 4 months after implant surgery, and crown delivery 1 month later. Both workflows involved free-model CAD-CAM crown fabrications. The crowns were scanned before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate the dimensional changes using Geomagic Control software. Chairside times for the entire workflow were recorded. Kruskal-Wallis was performed to compare crown adjustments between two groups, while One-way ANOVA was used to compare chairside time durations between the test and control groups. RESULTS: All crowns were delivered without refabrication. The average maximum occlusion adjustment of crowns was -353.2 ± 207.1 µm in the test group and -212.7 ± 150.5 µm in the control group (p = 0.02). The average area of occlusal adjustment, measured as an area of deviation larger than 100 µm, was 14.8 ± 15.3 and 8.4 ± 8.1 mm2 in the test and control groups, respectively (p = 0.056). There were no significant differences in the mesial and distal contact adjustment amounts, or the maximum deviations of the proximal area, between the two groups. The mean chair-side time was 50.25 ± 13.48 and 51.20 ± 5.34 min in the test and control groups, respectively (p = 0.763). CONCLUSIONS: The immediate impression method in the digital workflow for single-unit implants required more occlusal adjustments of crowns but showed similar chairside times compared to the staged impression method.

The facial-coronal ridge crest alterations after single immediate implant placement and provisionalization with thin buccal plate phenotype in anterior maxilla: A radiographic case-series study.

AIM: To explore the features of and potential landmarks that predict crestal ridge remodeling after immediate implant placement and provisionalization (IIPP) with thin buccal plate phenotype in the anterior maxilla. MATERIALS AND METHODS: Patients requiring IIPP of single maxillary incisor with thin buccal bone plate (<1 mm) were recruited. Cone-beam computed tomography (CBCT), performed before and 6 months after the intervention, were three-dimensionally superimposed. A virtual line connecting the bony emergence points of adjacent teeth was drawn as a reference. The facial-coronal alveolar crest of the extraction socket and healed ridge were located in mesial, middle and distal cross-sectional planes, and linear ridge reductions were measured. The correlation between ridge reduction and local factors was analyzed. RESULTS: Fifty patients were included. From the extraction socket to healed ridge, the alveolar crest underwent linear bone reduction of 1.50 ± 0.50, 1.54 ± 0.66 and 1.65 ± 0.73 mm in the mesial, middle, and distal regions in an apical-palatal direction. The middle region had significantly higher horizontal (facial-palatal) but lower vertical (coronal-apical) bone reduction than the mesial and distal areas (P < 0.01). The facial-coronal ridge crest of the healed ridge located close to the reference line. Ridge reduction positively correlated with the distance between the initial facial-coronal crest of the extraction socket and the reference line (P < 0.01). CONCLUSIONS: Alveolar crest of the socket lost its curvature and tended to attain a flat profile after IIPP due to inconsistent ridge reduction in middle, mesial and distal areas. The reference line may be a potential landmark for predicting the ridge crest after remodeling.

Heat shock-induced cold acclimation in cucumber through CsHSFA1d-activated JA biosynthesis and signaling.

Cucumber (Cucumis sativus) originated in tropical areas and is very sensitive to low temperatures. Cold acclimation is a universal strategy that improves plant resistance to cold stress. In this study, we report that heat shock induces cold acclimation in cucumber seedlings, via a process involving the heat-shock transcription factor HSFA1d. CsHSFA1d expression was improved by both heat shock and cold treatment. Moreover, CsHSFA1d transcripts accumulated more under cold treatment after a heat-shock pre-treatment than with either heat shock or cold treatment alone. After exposure to cold, cucumber lines overexpressing CsHSFA1d displayed stronger tolerance for cold stress than the wild type, whereas CsHSFA1d knockdown lines obtained by RNA interference were more sensitive to cold stress. Furthermore, both the overexpression of CsHSFA1d and heat-shock pre-treatment increased the endogenous jasmonic acid (JA) content in cucumber seedlings after cold treatment. Exogenous application of JA rescued the cold-sensitive phenotype of CsHSFA1d knockdown lines, underscoring that JA biosynthesis is key for CsHSFA1d-mediated cold tolerance. Higher JA content is likely to lead to the degradation of CsJAZ5, a repressor protein of the JA pathway. We also established that CsJAZ5 interacts with CsICE1. JA-induced degradation of CsJAZ5 would be expected to release CsICE1, which would then activate the ICE-CBF-COR pathway. After cold treatment, the relative expression levels of ICE-CBF-COR signaling pathway genes, such as CsICE1, CsCBF1, CsCBF2 and CsCOR1, in CsHSFA1d overexpression lines were significantly higher than in the wild type and knockdown lines. Taken together, our results help to reveal the mechanism underlying heat shock-induced cold acclimation in cucumber.

The jasmonate-induced bHLH gene SlJIG functions in terpene biosynthesis and resistance to insects and fungus.

Jasmonic acid (JA) is a key regulator of plant defense responses. Although the transcription factor MYC2, the master regulator of the JA signaling pathway, orchestrates a hierarchical transcriptional cascade that regulates the JA responses, only a few transcriptional regulators involved in this cascade have been described. Here, we identified the basic helix-loop-helix (bHLH) transcription factor gene in tomato (Solanum lycopersicum), METHYL JASMONATE (MeJA)-INDUCED GENE (SlJIG), the expression of which was strongly induced by MeJA treatment. Genetic and molecular biology experiments revealed that SlJIG is a direct target of MYC2. SlJIG knockout plants generated by gene editing had lower terpene contents than the wild type from the lower expression of TERPENE SYNTHASE (TPS) genes, rendering them more appealing to cotton bollworm (Helicoverpa armigera). Moreover, SlJIG knockouts exhibited weaker JA-mediated induction of TPSs, suggesting that SlJIG may participate in JA-induced terpene biosynthesis. Knocking out SlJIG also resulted in attenuated expression of JA-responsive defense genes, which may contribute to the observed lower resistance to cotton bollworm and to the fungus Botrytis cinerea. We conclude that SlJIG is a direct target of MYC2, forms a MYC2-SlJIG module, and functions in terpene biosynthesis and resistance against cotton bollworm and B. cinerea.

Crown Accuracy and Time Efficiency of Cement-Retained Implant-Supported Restorations in a Complete Digital Workflow: A Randomized Control Trial.

PURPOSE: This is a clinical study to compare complete digital workflows generated using intraoral scanning and the split-file technique with a conventional workflow for cement-retained implant-supported restorations. MATERIALS AND METHODS: Forty patients requiring posterior single-unit implant restorations were included. Twenty patients were randomly assigned to the complete digital workflow group, involving intraoral scanning and manufacture of cement-retained crowns using the split-file technique (test group). The remaining 20 patients were assigned to the hybrid workflow group (control group), involving conventional impressions and CAD-CAM fabricated crowns based on stone casts. Scanning of the crowns was performed before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate changes in dimensions using Geomagic Control 2014 software. Chair-side and laboratory times for the entire workflow were recorded. Independent-sample t tests were used for the statistical analysis. RESULTS: All crowns were inserted without refabrication. The average maximum occlusal adjustment of the crowns, measured as maximum deviation of occlusal area in superimposed pre and post scans, was -212.7 ± 150.5 and -330.7 ± 192.5 µm in the test and control groups, respectively (p = 0.037). The average area of occlusal adjustment, measured as area of deviation larger than 100 µm, was 8.4 ± 8.1 and 17.1 ± 12.3 mm2 in the test and control groups, respectively (p = 0.012). The mesial and distal contact adjustment amounts, maximum deviations of proximal area, were -33.0 ± 96.2 and -48.6 ± 70.5 µm in the test group, and -3.7 ± 66.7 µm and -11.4 ± 106.7 µm in the control group, respectively. The mean chair-side time was 20.20 ± 3.00 and 26.65 ± 4.53 minutes in the test and control groups, respectively (p < 0.001). The mean laboratory time was 43.70 ± 5.56 and 84.55 ± 5.81 minutes in the test and control groups, respectively (p < 0.001). CONCLUSIONS: Single-unit cement-retained crowns with complete digital workflows required fewer crown adjustments and had shorter clinical and laboratory times compared to conventional impressions and hybrid workflows. Digital impressions and the split-file technique provided customized abutments and cement-retained crowns, thus broadening the indications for digital workflows for implants.

First Report of Fusarium Yellows and Rhizome Rot Caused by Fusarium oxysporum f. sp. zingiberi on Ginger in the Continental United States.

Ginger (Zingiber officinale Roscoe) is one of the most widely consumed medicinal herb in the world, and the U.S. imports of ginger have risen in recent years because of its health benefits. Seed rhizome and soilborne diseases are serious concerns of ginger worldwide (Stirling 2004; Moreira et al. 2013), including the recent observations of Fusarium yellows and rhizome rot in the Commonwealth of Virginia. In October 2018 and 2019, ginger plants with yellowing of leaf margins and stunted growth were uprooted from a 9.1 m × 14.6 m high tunnel (HT) and from an outdoor raised bed at Virginia State University's Randolph farm. Disease incidence in the HT and the raised bed was estimated between 5-70%. Small pieces (2-5 mm) of symptomatic rhizomes were disinfected with 0.6% sodium hypochlorite solution and placed on potato dextrose agar (PDA) Petri plates to recover fungal isolates. Hyphal tips from these isolates were transferred to fresh PDA to obtain pure cultures. The fungal colonies were pinkish-white initially, and turned purplish-pink after 5-7 days of incubation at 25 °C. The microconidia were aseptate, oval or elliptical, hyaline, and measured 5 to 12 × 4 to 6 µm in size. Macroconidia were with 3 to 5 septations, curved like a sickle towards the ventral side, hyaline, smooth and thin-walled, and 15 to 40 × 3 to 6 µm in size. Fungal genomic DNA of one isolate (Gf-VA-3) was extracted from a 7-days old culture using PrepMan®Ultra (Thermo Fischer Scientific, Cheshire UK). Four conserved regions of the isolated pathogen, internal transcribed spacer (ITS), translation elongation factor (EF), ß-tubulin (Bt), and calmodulin (cal) gene regions were amplified using ITS1 and ITS4 (White et al. 1990), ef1α and ef2α (O'Donnell et al. 1998), Bt2a and Bt2b (Glass and Donaldson 1995), and calA1 and calQ1 (Carbone and Kohn 1999), respectively. PCR products were sequenced, and amplicons deposited in GenBank with accession numbers MT337417 for ITS, MT436712 for Bt, MT802441 for cal and MW816632 for EF. A 99-100% identity with Fusarium oxysporum was matched with accession nos. MW776326 for ITS, MN646766 for the ß-tubulin, MT010904 for the calmodulin and MN258350 for the translation elongation factor genes. For pathogenicity test, six 6-week-old healthy ginger plants grown on sterilized potting mix in the greenhouse were inoculated by injecting 3-ml of a 1 × 108 micro- and macro-conidia suspension per ml at the crown area transcending to the rhizome. Another set of six plants were injected with distilled and autoclaved water in the same way. After four weeks, leaves withered, plants exhibited yellowing and wilt followed by stunted growth and eventually complete collapse of the six inoculated plants, however control plants showed none of the symptoms. The same pathogen was re-isolated from the inoculated plants. The pathogenicity test was repeated, and the same results were observed. Fusarium yellows and rhizome rot has been reported from Hawaii in the U.S. (Trujillo 1963), Brazil (Moreira et al. 2013), Australia (Stirling 2004), China (Li et al. 2014), and India (Shanmugam et al. 2013). To our knowledge, this is the first report of Fusarium yellows and rhizome rot on ginger in the Continental U.S. The disease is seed rhizome and soilborne leading to poor establishment and hence economic loss in ginger production.

SlTLFP8 reduces water loss to improve water-use efficiency by modulating cell size and stomatal density via endoreduplication.

Improving plant water-use efficiency (WUE) is important to plant survival and crop yield in the context of water limitation. In this study, SlTLFP8 (Tubby-like F-box protein 8) was identified as an osmotic-induced gene in tomato. Transgenic tomato with up-regulated expression of SlTLFP8 showed enhanced water-deficient resistance, whereas knockout mutants generated by CRISPR/Cas9 were more sensitive to water deficit. SlTLFP8 overexpression significantly enhanced WUE by suppressing transpiration under both water-sufficient and water-deficient conditions. Further study showed that overexpressing SlTLFP8 significantly increased leaf epidermal cell size and thereby decreased stomatal density 10-20%, conversely SlTLFP8 knockout resulted in decreased cell size and thereby increased stomatal density 20-50%. SlTLFP8 overexpression and knockout modulated ploidy levels in leaf cells. Changes in expression of cell cycle related genes also indicated that SlTLFP8 affected cell size and stomatal density through endocycle transition. Despite changes in stomata density and transpiration, altering the expression of SlTLFP8 did not change photosynthesis. Additionally, biomass was not altered and there was little difference in fruit yield for transgenic and wild type lines under water-sufficient and water-deficient conditions. Our results demonstrate the effect of SlTLFP8 on endoreduplication and the potential of SlTLFP8 for improvement of WUE. BRIEF SUMMERY: This work found a new mechanism of TLP (Tubby like protein) response to water-deficient stress. SlTLFP8, a member of TLP family, regulates water-deficient resistance by modulating water loss via affecting stomatal density. Expression of SlTLFP8 was induced by osmotic stress. Transgenic tomato lines with SlTLFP8 overexpression or SlTLFP8 knockout showed significantly differences in water-use efficiency (WUE) and water-deficient resistance. The difference of leaf water loss caused by transpiration is the main explanation of the difference in WUE and water-deficient resistance. Additionally, overexpressing SlTLFP8 significantly decreased stomatal density, while SlTLFP8 knockout resulted in increased stomatal density, and SlTLFP8 affected stomatal density through endoreduplication and altered epidermal cell size. Despite changes in stomata density, altering the expression of SlTLFP8 did not result in distinct changes in photosynthesis, biomass and yield of tomato.

Melatonin promotes carotenoid biosynthesis in an ethylene-dependent manner in tomato fruits.

In tomato, red color is a key commercial trait and arises from the accumulation of carotenoids. Previous studies have revealed that melatonin promotes lycopene accumulation and ethylene production. However, it is unclear if melatonin similarly increases other carotenoids, and whether any increase of carotenoids in tomato fruit is directly related to ethylene production. In this study, changes in carotenoid profiles during fruit ripening were investigated in control (CK) and in fruits treated with melatonin (M50). The α, ß-carotene, and lycopene levels were significantly increased in M50, and there was increased carotenoid biosynthetic gene expression. We also observed up-regulated transcript levels of SlRIN, SlCNR, and SlNOR in M50 compared to CK. To better understand the regulation of carotenoid biosynthesis by melatonin and its potential response to endogenous ethylene, we tested an ethylene-insensitive mutant, Never ripe (Nr). Melatonin-treated Nr failed to accumulate more carotenoids compared to CK, although there was significantly changed ethylene production. Additionally, there was no general upregulation of expression of ripening-related genes in this mutant under melatonin treatment. These results suggest melatonin function might require ethylene to promote carotenoid synthesis in tomato.

Hard and soft tissue alterations during the healing stage of immediate implant placement and provisionalization with or without connective tissue graft: A randomized clinical trial.

AIMS: To evaluate the hard and soft tissue alterations of immediately placed and provisionalized implants with or without connective tissue graft (CTG). MATERIALS AND METHODS: Single unsalvageable maxillary incisors were replaced with immediately placed and provisionalized implants in 42 participants. The patients were randomly assigned to receive simultaneous CTG (test group) and not receive CTG (control group). Digital impression and cone-beam computed tomography images were obtained before extraction and after 6 months. Mid-facial gingival margin migrations, soft tissue contour changes and hard tissue remodelling were analysed and compared between the two groups using three-dimensional superimposition method. RESULTS: Forty participants completed the study. The test group showed significantly less buccal tissue collapse in the area 2-5 mm apical to the gingival margin. In both groups, the mid-facial gingival margin migrated in an apico-palatal direction and the socket void, except for a triangular space in the bucco-coronal region, demonstrated radiographic new bone formation without statistically significant differences. CONCLUSIONS: The CTG used with immediate implant placement and provisionalization could compensate for the facial tissue collapse, but it did not benefit maintenance of the mid-facial gingival margin position during the 6-month follow-up. New bone formation observed radiographically can be expected in most areas of the socket void, regardless of CTG use (ChiCTR-1900028494).

Analysis and comparison of seed protein, oil, and sugars in edamame dried using two oven-drying methods and mature soybeans.

BACKGROUND: Edamame, a vegetable soybean (Glycine max) grown mainly in Asia, has high nutritional and market value and is a relatively new crop to North America. By 2 years of field trials, we evaluated the seed composition traits in 54 genotypes to analyze the differences and relationship between edamame seeds dried by two oven-drying methods and mature soybeans. RESULTS: The genotypic differences were significant for all the traits investigated. Significant differences also existed between the two sets of dried edamame and mature seeds. Protein content in mature soybean averaged 426.8 g kg-1 , and 432.8 g kg-1 and 405.6 g kg-1 for shelled-dried and unshelled-dried edamame respectively. Oil content in shelled-dried and unshelled-dried edamame averaged 206.3 g kg-1 and 212.6 g kg-1 respectively, and 195.8 g kg-1 for mature soybean. Sucrose content in mature soybean (60.2 g kg-1 ) was approximately 1.5 and 3 times that of unshelled-dried and shelled-dried edamame respectively. Mature soybean also exhibited the highest concentrations of stachyose and total sugars, followed by unshelled-dried and shelled-dried edamame. The broad-sense heritability estimates of traits in mature soybean (49.41-89.16%) were higher than those of edamame (10.26-78.96%). Higher broad-sense heritability was uncovered for protein and oil, but lower estimates for sugars, fiber, and ash. Positive correlations were detected between the two sets of edamame seeds and mature soybean for protein and oil (r = 0.63-0.88). CONCLUSION: The results suggest that indirect selection through mature seeds is helpful for the improvement of protein and oil in edamame, whereas the improvement of seed sugars in edamame is more challenging. © 2020 Society of Chemical Industry.

Accuracy of virtual interocclusal records for partially edentulous patients.

STATEMENT OF PROBLEM: Intraoral scans and virtual interocclusal records (VIRs) are widely used for contemporary prosthodontic treatment of patients with partial edentulism. The accuracy of VIRs in various clinical conditions is unclear. PURPOSE: The purpose of this in vitro study was to investigate whether the span and location of edentulous areas affect the accuracy of VIRs. MATERIAL AND METHODS: Five sets of master stone casts were duplicated from a typodont model (Prosthetic Restoration Jaw Model; Nissin Dental) and then assigned into 5 study groups. Six pairs of interarch markers were placed on the master stone casts as reference points for measurements. The 5 study groups were group 1-Post: 1 posterior tooth missing; group 3-Post: 3 posterior teeth missing; group 6-Ant: 6 anterior teeth missing; group Bil-Post: bilateral posterior teeth missing; and group Dent: completely dentate arch. Master stone casts along with VIRs were scanned 10 times in each group by using an intraoral scanner (IOS) (Dental Wings Intraoral Scanner; Dental Wings Inc). Digital measurement of distances between the interarch markers was obtained on all digitally articulated casts and compared with the manual measurements (with electronic calipers with an accuracy of 0.02 mm). In addition, the differences (absolute values) between the digital and manual measurements were calculated at the edentulous locations for the groups 1-Post, 3-Post, 6-Ant, and Bil-Post and were compared with the corresponding interarch marker positions in the group Dent. Two-sample t tests were used for the statistical analysis (α=.05). RESULTS: The overall differences (mean ±standard deviation) between digital and manual measurements were group 1-Post: 0.10 ±0.19 mm, group 3-Post: 0.28 ±0.63 mm; group 6-Ant: 0.19 ±0.20 mm; group Bil-Post: 0.28 ±0.25 mm; and group Dent: 0.05 ±0.18 mm. Group Dent was the only group with no significant differences between digital and manual measurements at all 6 interarch marker positions and was used as the reference to analyze the measurements in the edentulous areas. No statistical difference was found (P=.237) at the group 1-Post's edentulous area when compared with the group Dent. In the group 3-Post, the edentulous areas showed statistically significant difference when compared with those of the group Dent (P=.002 and P=.003). In the group 6-Ant, the edentulous areas showed statistical differences when compared with those of the group Dent (P=.019 and P=.008). In the group Bil-Post, only 1 side of the edentulous areas showed statistical differences when compared with group Dent (P=.006 and P=.034). CONCLUSIONS: The span and location of edentulous areas impact the accuracy of VIRs. For a single missing posterior tooth, VIRs could achieve a high level of accuracy comparable with that of the dentate condition. Unilateral and bilateral extended edentulous spans with 3 or more missing posterior teeth and the extended edentulous span in the anterior region all affected the accuracy of VIRs.

Melatonin acts synergistically with auxin to promote lateral root development through fine tuning auxin transport in Arabidopsis thaliana.

Melatonin (N-acetyl-5-methoxytryptamine) plays important roles in plant developmental growth, especially in root architecture. The similarity in both chemical structure and biosynthetic pathway suggests a potential linkage between melatonin and auxin signaling. However the molecular mechanism regulating this melatonin-mediated root architecture changes is not yet elucidated. In the present study, we re-analyzed previously conducted transcriptome data and identified 16 auxin-related genes whose expression patterns were altered by treatment with melatonin. Several of these genes encoding important auxin transporters or strongly affecting auxin transport were significantly down regulated. In wild type Arabidopsis, Melatonin inhibited both primary root growth and hypocotyl elongation, but enhanced lateral root development in a dose dependent manner. However, the lateral-root-promoting role of melatonin was abolished when each individual null mutant affecting auxin transport including pin5, wag1, tt4 and tt5, was examined. Furthermore, melatonin acts synergistically with auxin to promote lateral root development in wild type Arabidopsis, but such synergistic effects were absent in knockout mutants of individual auxin transport related genes examined. These results strongly suggest that melatonin enhances lateral root development through regulation of auxin distribution via modulation of auxin transport. A working model is proposed to explain how melatonin and auxin act together to promote lateral root development. The present study deepens our understanding of the relationship between melatonin and auxin signaling in plant species.

SoHSC70 positively regulates thermotolerance by alleviating cell membrane damage, reducing ROS accumulation, and improving activities of antioxidant enzymes.

High temperature is a major environmental factor affecting plant growth. Heat shock proteins (Hsps) are molecular chaperones that play important roles in improving plant thermotolerance during heat stress. Spinach (Spinacia oleracea) is very sensitive to high temperature; however, the specific function of Hsps in spinach is unclear. In this study, cytosolic heat shock 70 protein (SoHSC70), which was induced by heat stress, was cloned from spinach. Overexpressing SoHSC70 in spinach calli and Arabidopsis enhanced their thermotolerance. In contrast, spinach seedlings with silenced SoHSC70 by virus-induced gene silencing (VIGS) showed more sensitivity to heat stress. Further analysis revealed that overexpressing SoHSC70 altered relative electrical conductivity (REC), malondialdehyde (MDA) content, photosynthetic rate, reactive oxygen species (ROS) accumulation and the activities of antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) after the heat treatment. Taken together, our results suggest that overexpressing SoHSC70 positively affects heat tolerance by reducing membrane damage and ROS accumulation and improving activities of antioxidant enzymes.

PvNAC1 increases biomass and enhances salt tolerance by decreasing Na+ accumulation and promoting ROS scavenging in switchgrass (Panicum virgatum L.).

Switchgrass (Panicum virgatum L.) is a bioenergy crop; thus, it is important to improve biomass to effectively produce bioethanol, particularly under adverse stress conditions. NAC transcription factors are involved in the abiotic stress response. PvNAC1 was isolated in the nucleus of switchgrass, with its C-terminal region containing a transcriptional activation domain. PvNAC1 expression was induced by dehydration, salt, H2O2, and abscisic acid treatments. Overexpressing (OE) PvNAC1 improved growth performance, leading to significantly taller and heavier (dry weight) plants. Moreover, cellulose content was significantly higher in OE plants, indicating that PvNAC1 plays an important role regulating growth and bioethanol production. PvNAC1 RNA interference (RNAi) switchgrass plants exhibited reduced dry weight and cellulose content. OE PvNAC1 enhanced tolerance to salt stress, through higher reactive oxygen species scavenging ability and less Na+ and more K+ accumulation in roots and shoots. RNAi plants were more sensitive to salt stress. The quantitative polymerase chain reaction results revealed that some stress responsive genes, three antioxidant enzymatic genes, and an ion homeostasis-related gene were upregulated in OE plants and downregulated in RNAi plants. These results show that PvNAC1 functions as a transcriptional activator in response to salt stress and growth.

Melatonin Alleviates Copper Toxicity via Improving Copper Sequestration and ROS Scavenging in Cucumber.

Melatonin plays an important role in stress tolerance in plants. In this study, exogenous melatonin significantly alleviated the dwarf phenotype and inhibited the decrease of plant fresh weight induced by excess copper (Cu2+). Our results indicated that melatonin alleviated Cu2+ toxicity by improving Cu2+ sequestration, carbon metabolism and ROS (reactive oxygen species) scavenging, rather than by influencing the Cu2+ uptake under excess Cu2+ conditions. Transcriptome analysis showed that melatonin broadly altered gene expression under Cu2+ stress. Melatonin increased the levels of glutathione and phytochelatin to chelate excess Cu2+ and promoted cell wall trapping, thus keeping more Cu2+ in the cell wall and vacuole. Melatonin inhibited ROS production and enhanced antioxidant systems at the transcriptional level and enzyme activities, thus building a line of defense in response to excess Cu2+. The distribution of nutrient elements was recovered by melatonin which was disturbed by Cu2+. In addition, melatonin activated carbon metabolism, especially glycolysis and the pentose phosphate pathway, to generate more ATP, an intermediate for biosynthesis. Taken together, melatonin alleviated Cu2+ toxicity in cucumber via multiple mechanisms. These results will help to resolve the toxic effects of Cu2+ stress on plant growth and development. These results can be used for new strategies to solve problems associated with Cu2+ stress.

Enhanced removal of coumarin by a novel O3/SPC system: Kinetic and mechanism.

A high-efficient, eco-friendly and applicable oxidant of percarbonate (SPC, Na2CO3·1.5H2O2) is applied as oxidant in ozonation (O3) process. In this work, coumarin (COU) decomposition by O3 and O3/SPC was proposed in terms of diverse parameters, including ozone concentration, SPC dosage and pH, with regard to the pseudo-first-order kinetic model. About 96.5% of 25 mg L-1 COU was removed by 209.3 mg L-1 SPC and 2.08 mg L-1 O3 within 30 min, whereas 49.8% of COU was exhausted in O3 system alone. High ozone concentration and pH could enhance COU removal, and overdose SPC has an inhibition effect as CO32- could react with ·OH. Furtherly, the generation of hydroxyl radicals (OH) via a chain reaction in O3 was ascertained based on indirect alcohols quenching tests and direct electron spin resonance (ESR) spin-trapping tests, though high initial SPC concentration led to no trapping of OH by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) in O3/SPC. According to the concentration of dissolved ozone and prior study, a fast reaction kinetic model was estimated firstly for O3/SPC system and well fitted with different condition. The hydroxylated intermediates of 7-hydroxylcoumarin and 6,7-hydroxylcoumarin were recognized and the degradation pathways were proposed. The findings of the study can broaden the research direction of SPC and provide a new application information for SPC in environmental pollution control.

Overexpression of BoNAC019, a NAC transcription factor from Brassica oleracea, negatively regulates the dehydration response and anthocyanin biosynthesis in Arabidopsis.

NACs are one of the largest transcription factor families in plants and are involved in the response to abiotic stress. BoNAC019, a homologue of AtNAC019, was isolated from cabbage (Brassica oleracea). BoNAC019 was localized in the nucleus and functioned as a transcriptional activator. The expression of BoNAC019 was induced by dehydration, salt, abscisic acid (ABA), and H2O2 treatments. BoNAC019 overexpressing plants were generated to explore the function of BoNAC019 in response to drought stress. Overexpression (OE) of BoNAC019 reduced drought tolerance with lower survival rate, higher water loss rate, lower proline content and ABA content. The seed germination and root length assays of BoNAC019-OE plants showed decreased sensitivity to ABA. Under drought condition, antioxidant enzymes and anthocyanin content decreased in BoNAC019 -OE plants, resulting in the accumulation of more reactive oxygen species (ROS), which cause damage to plants. Several stress-responsive genes, antioxidant enzymatic genes, anthocyanin biosynthetic genes and ABA signaling genes were down-regulated under drought condition while the ABA catabolism genes were induced in BoNAC019-OE plants under both normal and drought conditions. Our results demonstrated that BoNAC019 might participated in regulating drought tolerance by inducing ABA catabolism genes and decreasing ABA content.

Relationship between ADAMTS14/rs4747096 gene polymorphism and knee osteoarthritis in Chinese population.

To investigate the association between single nucleotide polymorphisms (SNPs) of A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 14 (ADAMTS14) gene and susceptibility to knee osteoarthritis (KOA) in Chinese Han population. Using a case-control design, we enrolled 346 KOA patients and 480 healthy controls. Peripheral blood samples were extracted from each subject. Genotype was determined by sequencing PCR products. The genotype frequencies between cases and controls were compared. The genotype distribution was in accordance with Hardy-Weinberg equilibrium. The minor G allele in case group was significantly higher than in the control group (21.4 compared with 8.8%, P=0.000, odds ratio (OR) = 1.71 (95% confidence interval (CI): 1.39-2.11). The GG genotype and the GG/AG combination were more common in the osteoarthritis (OA) group than in the control group. Compared with AA genotype, the GG (OR = 3.09, 95%CI: 2.01-4.75), AG (OR = 2.55, 95%CI: 1.64-3.96), and GG/AG (OR = 1.57, 95%CI: 1.19-2.07) increased the risk of OA. Multiple logistic confirmed the findings by adjusting some potential factors. Subgroup analysis indicated that the ras4747096 was still significantly associated with KOA. There were no significant differences in allele frequency or genotypes frequency for erythrocyte sedimentation rate and C-reaction protein in OA patients (P>0.05). ADAMTS14 gene polymorphism was associated with KOA, and the GG genotype increased the risk of KOA in Chinese Han population. The ADAMTS14 may be a diagnostic marker and therapeutic target for KOA treatment. The future study should explore the specific molecular mechanism.

CsATAF1 Positively Regulates Drought Stress Tolerance by an ABA-Dependent Pathway and by Promoting ROS Scavenging in Cucumber.

The NAC transcription factors play vital roles in responding to drought stress in plants; however, the molecular mechanisms remain largely unknown in cucumber. Suppression of CsATAF1 via RNA interference (RNAi) weakened drought stress tolerance in cucumber due to a higher water loss rate in leaves, a higher level of hydrogen peroxide (H2O2) and superoxide radicals (O2·-), increased malondialdehyde (MDA) content, lower Fv/Fm ratios and lower antioxidant enzyme activity. The analysis of root length and stomatal apertures showed that CsATAF1-RNAi cucumber plants were less responsive to ABA. In contrast, CsATAF1-overexpression (OE) plants showed increased drought stress tolerance and sensitivity to ABA. Quantitative PCR (qPCR) analysis showed that expression of several stress-responsive genes was significantly up-regulated in CsATAF1-OE transformants and down-regulated in CsATAF1-RNAi transformants. CsABI5, CsCu-ZnSOD and CsDREB2C were verified as direct target genes of CsATAF1. Yeast one-hybrid analysis and electrophoretic mobility shift assay (EMSA) further substantiated that CsATAF1 bound to the promoters of CsABI5, CsCu-ZnSOD and CsDREB2C. Transient expression in tobacco leaves and cucumber protoplasts showed that CsATAF1 directly up-regulated the expression of CsABI5, CsCu-ZnSOD and CsDREB2C. Our results demonstrated that CsATAF1 functioned as a positive regulator in response to drought stress by an ABA-dependent pathway and decreasing reactive oxygen species (ROS) accumulation in cucumber.