Leaf shape, planting density, and nitrogen application affect soybean yield by changing direct and diffuse light distribution in the canopy.

When attempting to maximize the crop yield from field-grown soybean (Glycine max (L.) Merr.) by means of improving the light conditions for photosynthesis in the canopy, it is crucial to find the optimal planting density and nitrogen application rate. The soybean plants that were the subject of our experiment were cultivated in N-dense mutual pairs, and included two cultivars with different leaf shapes; one cultivar sported ovate leaves (O-type) and the other lanceolate leaves (L-type). We analyzed the results quantitatively to determine the amount of spatial variation in light distribution and photosynthetic efficiency across the canopy, and to gauge the effect of the experimental parameters on the yield as well as the photosynthetic light and nitrogen use efficiency of the crop. Results indicate that the different leaf shapes were responsible for significant disparities between the photosynthetic utilization of direct and diffuse light. As the nitrogen fertilizer rate and the planting density increased, the soybean plants responded by adjusting leaf morphology in order to maximize the canopy apparent photosynthetic light use efficiency, which in turn affected the leaf nitrogen distribution in the canopy. Despite the fact that the light interception rate of the canopy of the L-type cultivar was lower than that of the canopy of the O-type cultivar, we found its canopy apparent photosynthetic nitrogen and light use efficiency were higher. It was interesting to note, however, that the nitrogen and light use efficiency contributions associated with exposure to diffuse light were greater for the latter than for the former.

Copper-Based Electrocatalysts for Nitrate Reduction to Ammonia.

Ammonia (NH3) is a highly important industrial chemical used as fuel and fertilizer. The industrial synthesis of NH3 relies heavily on the Haber-Bosch route, which accounts for roughly 1.2% of global annual CO2 emissions. As an alternative route, the electrosynthesis of NH3 from nitrate anion (NO3-) reduction (NO3-RR) has drawn increasing attention, since NO3-RR from wastewater to produce NH3 can not only recycle waste into treasure but also alleviate the adverse effects of excessive NO3- contamination in the environment. This review presents contemporary views on the state of the art in electrocatalytic NO3- reduction over Cu-based nanostructured materials, discusses the merits of electrocatalytic performance, and summarizes current advances in the exploration of this technology using different strategies for nanostructured-material modification. The electrocatalytic mechanism of nitrate reduction is also reviewed here, especially with regard to copper-based catalysts.

Proteomic analysis of protein lysine 2-hydroxyisobutyrylation (Khib) in soybean leaves.

BACKGROUND: Protein lysine 2-hydroxyisobutyrylation (Khib) is a novel post-translational modification (PTM) discovered in cells or tissues of animals, microorganisms and plants in recent years. Proteome-wide identification of Khib-modified proteins has been performed in several plant species, suggesting that Khib-modified proteins are involved in a variety of biological processes and metabolic pathways. However, the protein Khib modification in soybean, a globally important legume crop that provides the rich source of plant protein and oil, remains unclear. RESULTS: In this study, the Khib-modified proteins in soybean leaves were identified for the first time using affinity enrichment and high-resolution mass spectrometry-based proteomic techniques, and a systematic bioinformatics analysis of these Khib-modified proteins was performed. Our results showed that a total of 4251 Khib sites in 1532 proteins were identified as overlapping in three replicates (the raw mass spectrometry data are available via ProteomeXchange with the identifier of PXD03650). These Khib-modified proteins are involved in a wide range of cellular processes, particularly enriched in biosynthesis, central carbon metabolism and photosynthesis, and are widely distributed in subcellular locations, mainly in chloroplasts, cytoplasm and nucleus. In addition, a total of 12 sequence motifs were extracted from all identified Khib peptides, and a basic amino acid residue (K), an acidic amino acid residue (E) and three aliphatic amino acid residues with small side chains (G/A/V) were found to be more preferred around the Khib site. Furthermore, 16 highly-connected clusters of Khib proteins were retrieved from the global PPI network, which suggest that Khib modifications tend to occur in proteins associated with specific functional clusters. CONCLUSIONS: These findings suggest that Khib modification is an abundant and conserved PTM in soybean and that this modification may play an important role in regulating physiological processes in soybean leaves. The Khib proteomic data obtained in this study will help to further elucidate the regulatory mechanisms of Khib modification in soybean in the future.

Clinical evidence for association of neoadjuvant chemotherapy or chemoradiotherapy with efficacy and safety in patients with resectable esophageal carcinoma (NewEC study).

BACKGROUND: The efficacy and safety of neoadjuvant treatment over surgery alone and that of neoadjuvant chemoradiotherapy (NCRT) over neoadjuvant chemotherapy (NCT) in resectable esophageal carcinoma remains inconclusive. This study (NewEC) used global data to comprehensively evaluate these comparisons and to provide a preferable strategy for patient subsets. METHODS: This study included a meta-analysis of randomized controlled trials (RCTs) identified from inception to May 2019 from PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and congresses and a registry-based cohort study with patients from Massachusetts General Hospital (Massachusetts, USA) and Guangdong Provincial People's Hospital (Guangzhou, China) recruited from November 2000 and June 2017, to cross-validate the comparisons among NCRT versus NCT versus surgery. The GRADE approach was used to assessed quality of evidence in meta-analysis. Neural network machine learning propensity score-matched analysis was used to account for confounding by patient-level characteristics in the cohort study. The primary endpoint was overall survival (OS). The study was registered with PROSPERO CRD42017072242 and ClinicalTrials.gov NCT04027543. FINDINGS: Of 22,070 studies assessed, there were 38 (n = 6,993 patients) eligible RCTs. Additionally, 423 out of 467 screened patients were included in the cohort study. The results from trials showed that NCT had a better OS than surgery alone (hazard ratio [HR] 0·88, 95% confidence interval [CI] 0·79-0·98; high quality) and was only favorable for adenocarcinoma (HR 0·83, 95% CI 0·72-0·96; moderate quality). High-quality evidence showed a significantly better OS for NCRT than surgery alone (HR 0·74, 95% CI 0·66-0·82) for both adenocarcinoma (HR 0·73, 95% CI 0·62-0·86) and squamous cell carcinoma (SCC) (HR 0·73, 95% CI 0·65-0·83). The OS benefit of NCRT over NCT was seen in the pairwise (HR 0·78, 95% CI 0·62-0·99; high quality) and network (HR 0·82, 95% CI 0·72-0·93; high quality) meta-analyses, with similar results before (HR 0·60, 95% CI 0·40-0·91) and after (HR 0·44, 95% CI 0·25-0·77) matching in the cohort study, leading to a significantly increased 5-year OS rate in both adenocarcinoma and SCC before and after matching. The increased benefits from NCT or NCRT were not associated with the risk of 30-day or in-hospital mortality. INTERPRETATION: NewEC Study provided high-quality evidence supporting the survival benefits of NCRT or NCT over surgery alone, with NCRT presenting the greatest benefit for resectable esophageal carcinoma. FUNDING: National Science and Technology Major Project, the National Natural Science Foundation of China, the Natural Science Foundation of Guangdong Province, the Guangzhou Science and Technology Major Program, the Medical artificial intelligence project of Sun Yat-Sen Memorial Hospital, the Guangdong Science and Technology Department, the Guangdong Province Medical Scientific Research Foundation, and Guangdong Provincial People's Hospital Intermural Program.

Polar layered coordination polymers incorporating triazacyclononane-triphosphonate metalloligands.

Reactions of metalloligands MIII(notpH3) (M = Fe, Co and notpH6 = 1,4,7-triazacyclononane-1,4,7-triyl-tris(methylenephosphonic acid)) with Zn(OAc)2 under hydrothermal conditions resulted in new metal phosphonates Zn2Fe(notp)Cl(H2O) (1) and ZnCo(notpH)(H2O)·2H2O (2). They crystallize in polar space groups P63 (for 1) and Pca21 (for 2), respectively, and exhibit layer structures in which the inorganic layers are separated by the organic groups of the notp ligands. However, the layer topologies of the two compounds are quite different. In 1, the layer contains 6-membered rings composed of one {FeN3O3} octahedron, one {Zn1O3Cl}, one {Zn2O4} and three {PO3C} tetrahedra via corner-sharing connections, while in 2, the layer contains 10-membered rings composed of two {CoO3N3} octahedra, three {ZnO4} and five {PO3C} tetrahedra via vertex-sharing connections. Dielectric measurements on single crystals of 2 confirmed the presence of high dielectric anisotropy. Proton conductivity measurements revealed that the proton conduction is more favourable in 2 due to the presence of a continuous hydrogen bond network in this compound.

Comparative transcriptome analysis reveals that lactose acts as an inducer and provides proper carbon sources for enhancing exopolysaccharide yield in the deep-sea bacterium Zunongwangia profunda SM-A87.

Many marine bacteria secrete exopolysaccharides (EPSs) that have important ecological and physiological functions. Numerous nutritional and environmental factors influence bacterial EPS production. However, the regulatory mechanisms of EPS production are poorly understood. The deep-sea Bacteroidetes bacterium Zunongwangia profunda SM-A87 can produce high quantities of EPS, and its EPS production is enhanced significantly by lactose. Here, we studied the reasons behind the significant advantage that lactose has over other carbon sources in EPS production in SM-A87. RNA-seq technologies were used to study lactose-regulated genes in SM-A87. The expression level of genes within the EPS gene cluster was up-regulated when lactose was added. Supplement of lactose also influenced the expression of genes located outside the EPS gene cluster that are also involved in EPS biosynthesis. The major glycosyl components of SM-A87 EPS are mannose, glucose and galactose. Genomic metabolic pathway analyses showed that the EPS precursor GDP-mannose can be synthesized from glucose, while the precursor UDP-glucose must be synthesized from galactose. Lactose can provide glucose and galactose simultaneously and prevent glucose inhibition. Lactose can also greatly stimulate the growth of SM-A87. Taken together, lactose acts not only as an inducer but also as a carbohydrate source for EPS production. This research broadens our knowledge of the regulation of EPS production in marine bacteria.

[Study on effect of huatuo zaizao extractum on focal cerebral ischemia/reperfusion neurogenesis in rats and its mechanisms].

OBJECTIVE: To observe the effect of Huatuo Zaizao extractum (HTZZ) on focal cerebral ischemia/reperfusion (I/R) neurogenesis in rats induced by middle cerebral artery occlusion (MCAO) and its mechanism. METHOD: Totally 55 healthy adult male Sprague-Dawley rats were divided into the sham operation group, the MCAO model group and HTZZ high, middle and low dose groups (5, 2.5, 1.25 g x kg(-1)), with 11 rats in each group, and orally administered with drugs. The focal cerebral ischemia model was established by performing a middle cerebral artery occlusion (MCAO, 90 min) followed by a seven-day reperfusion (once a day). The neurogenesis and expressions of extracellular signal-regulated kinase (ERK) and cAMP response element binding protein (CREB) were detected by the immunofluorescent staining. The enzyme linked immunosorbent assay (ELISA) was adopted to determine the vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). RESULT: MCAO (90 min) followed by a seven-day reperfusion resulted in the significant increase in the number of penumbra cortex newborn neurons (BrdU(+) -NeuN(+)), which was accompanied by the growth of ERK and CREB phosphorylation and VEGF and BDNF levels. HTZZ could promote the generation of newborn neurons (BrdU(+)-NeuN(+)) and the ERK and CREB phosphorylation and increase VEGF and BDNF levels at the ischemic side. CONCLUSION: HTZZ could promote the neurogenesis, which may be the interventional targets of effective traditional Chinese medicine Huatuo Zaizao extractum in promoting the self-repair function of the cerebral ischemic areas.

A novel exopolysaccharide from deep-sea bacterium Zunongwangia profunda SM-A87: low-cost fermentation, moisture retention, and antioxidant activities.

Many marine microorganisms can secrete exopolysaccharides (EPSs) which have important applications in biotechnology. We have purified a novel EPS from deep-sea bacterium Zunongwangia profunda SM-A87, identified its glycosyl composition and linkage, and optimized its production to 8.9 g/l in previous studies. To reduce the fermentation cost, an economical fermentation medium containing 60.9 % whey, 10 g/l soybean meal, and 2.9 % NaCl was developed. The EPS yield of batch fermentation in this medium reached 12.1 ± 0.3 g/l. Fed-batch fermentation was conducted and led to an EPS yield of 17.2 ± 0.4 g/l, which represents the highest EPS yield ever reported for a marine bacterium. The EPS was extracted and it displayed good rheological properties, moisture-retention ability, and antioxidant activity. Particularly, its moisture-retention ability is superior to that of other marine bacterial EPSs reported to date. SM-A87 EPS also showed high antioxidant activity. These results suggest that SM-A87 EPS has promising potentials in biotechnology.

[Effect and mechanism of huatuo zaizao extractum on focal cerebral ischemia/reperfusion-induced blood-brain barrier injury in rats].

OBJECTIVE: To observe the effect and mechanism of Huatuo Zaizao extractum (HTZZ) on focal ischemia/reperfusion (I/R) blood-brain barrier injury induced by middle cerebral artery occlusion. METHOD: Sixty healthy male adult Sprague-Dawley rats was randomly divided into the sham operation group, the MCAO model group, the Tanakan (20 mg x kg(-1)) group, and high, middle and low-dose HTZZ groups (5, 2.5, 1.25 g x kg(-1)), with 10 in each group and single-dose duodenal administration. Middle cerebral artery occlusion was adopted to establish the rat focal I/R model. After ischemia for 90 min and reperfusion for 24 h, the pathological injury at the ischemia side was observed by HE staining. The blood-brain barrier structure was observed under transmission electron microscope. Expressions of G protein-coupled receptor kinases 2 (GRK2), matrix metalloproteinases 2 (MMP-2) and MMP-9 were detected by western blotting technique. RESULT: After 90 min MCAO/24 h reperfusion, penumbra cerebral cortical micro-vessels showed edema, mitochondrial injury, vacuolation, membrane injury and reduction. Along with the changes, sub-cells of G protein-coupled receptor kinase 2 (GRK2) in cortical penumbra brain tissues transferred from cytoplasm to membrane, with increase in expressions of MMP-2 and MMP-9. HTZZ could effectively recover cerebral micro-vascular endothelial edemaand blood-brain barrier ultrastructure injury induced by I/R, reduce expression of functional (membrane coupling) GRK2, and inhibit expressions of MMP-2 and MMP-9. CONCLUSION: Cell membrane coupling GRK2 may be the effective target of Huatuo Zaizao extractum.

Structure and ecological roles of a novel exopolysaccharide from the arctic sea ice bacterium Pseudoalteromonas sp. Strain SM20310.

The structure and ecological roles of the exopolysaccharides (EPSs) from sea ice microorganisms are poorly studied. Here we show that strain SM20310, with an EPS production of 567 mg liter(-1), was screened from 110 Arctic sea ice isolates and identified as a Pseudoalteromonas strain. The EPS secreted by SM20310 was purified, and its structural characteristics were studied. The predominant repeating unit of this EPS is a highly complicated α-mannan with a molecular mass greater than 2 × 10(6) Da. The backbone of the EPS consists of 2-α-, 6-α-mannosyl residues, in which a considerable part of the 6-α-mannosyl residues are branched at the 2 position with either single t-mannosyl residues or two mannosyl residues. The structure of the described EPS is different from the structures of EPSs secreted by other marine bacteria. Analysis of the ecological roles of the identified EPS showed that the EPS could significantly enhance the high-salinity tolerance of SM20310 and improve the survival of SM20310 after freeze-thaw cycles. These results suggest that the EPS secreted by strain SM20310 enables the strain to adapt to the sea ice environment, which is characterized by low temperature, high salinity, and repeated freeze-thaw cycles. In addition to its functions in strain SM20310, this EPS also significantly improved the tolerance of Escherichia coli to freeze-thaw cycles, suggesting that it may have a universal impact on microorganism cryoprotection.

[Application of case-based learning in clinical internship teaching of conservative dentistry and endodontics].

PURPOSE: To investigate the education effect of case-based learning (CBL) pattern on clinical internship of conservative dentistry and endodontics. METHODS: Forty-one undergraduates were randomly assigned into CBL group and traditional teaching group. After clinical internship in the department of conservative dentistry and endodontics for 11 weeks, each student in the 2 groups underwent comprehensive examinations including medical record writing, case analysis, academic knowledge, professional skills and the ability of winning the trust of the patients. The scores were compared between the 2 groups using SPSS 13.0 software package. RESULTS: There was no significant difference between the 2 groups with regard to the scores of academic knowledge and profession skills (P>0.05). However, the results of medical record writing, case analysis and the ability of winning the trust of the patients showed significant difference between the 2 groups(P<0.05). CONCLUSIONS: Proper application of CBL in clinical internship of conservative dentistry and endodontics contributes to improve students' ability of clinical thinking, synthetical analysis and adaptability to different patients.

Characterization of bacterial polysaccharide capsules and detection in the presence of deliquescent water by atomic force microscopy.

We detected polysaccharide capsules from Zunongwangia profunda SM-A87 with atomic force microscopy (AFM). The molecular organization of the capsules at the single-polysaccharide-chain level was reported. Furthermore, we found that with ScanAsyst mode the polysaccharide capsules could be detected even in the presence of deliquescent water covering the capsule.

4,4'-Bipyridine-pyridine-3,5-dicarb-oxy-lic acid (3/4).

In the title compound, 3C(10)H(8)N(2)·4C(7)H(5)NO(4), the asymmetric unit contains two mol-ecules of pyridine-3,5-dicarb-oxy-lic acid and one mol-ecule of 4,4'-bipyridine in general positions together with one mol-ecule of 4,4'-bipyridine lying across a centre of inversion, thus giving a 4:3 molar ratio of pyridine-3,5-dicarb-oxy-lic acid to 4,4'-bipyridine. The dihedral angle between the bipyridine rings on general positions is 21.2 (2)°. These mol-ecular units are linked by O-H⋯N hydrogen bonds forming an extended two-dimensional framework in the crystal.

Optimization of fermentation conditions and rheological properties of exopolysaccharide produced by deep-sea bacterium Zunongwangia profunda SM-A87.

Zunongwangia profunda SM-A87 isolated from deep-sea sediment can secrete large quantity of exopolysaccharide (EPS). Response surface methodology was applied to optimize the culture conditions for EPS production. Single-factor experiment showed that lactose was the best carbon source. Based on the Plackett-Burman design, lactose, peptone and temperature were selected as significant variables, which were further optimized by the steepest ascent (descent) method and central composite design. The optimal culture conditions for EPS production and broth viscosity were determined as 32.21 g/L lactose, 8.87 g/L peptone and an incubation temperature of 9.8°C. Under these conditions, the maximum EPS yield and broth viscosity were 8.90 g/L and 6551 mPa•s, respectively, which is the first report of such high yield of EPS from a marine bacterium. The aqueous solution of the EPS displayed high viscosity, interesting shearing thinning property and great tolerance to high temperature, a wide range of pH, and high salinity.

[FTIR spectrum and coagulation enhancement of exopolysaccharide secreted by an Antarctica bacterium Pseudoalteromona sp. Bsi20310].

Bsi20310 exopolysaccharide (Bsi20310 EPS) was secreted by a bacteria named Pseudoalteromonas sp. Bsi20310, isolated from Antarctic Sea ice. Crude Bsi20310 EPS was prepared by precipitation of the culture solution with ethanol, with proteins removed by using chloroform and butanol preparatorily. The results showed that Bsi20310 EPS improved the FeCl3 coagulation performance on synthetic water-soluble dye reactive red X-3B dyeing wastewater, obviously. The optimum coagulation enhancement of Bsi20310 EPS expressed by decolorization rate is from 16% to 84%, at pH near 10, Fe(III) concentration of 0. 98 mmol x L(-1) and Bsi20310 EPS concentration of 150 mg x L(-1), respectively. Fourier transform infrared spectroscopy (FTIR) was used to investigate the functional groups of Bsi20310 EPS, Fe(III)-Bsi20310 EPS floc and Fe(III)-Bsi20310 EPS-reactive red X-3B floc. The spectra showed that Bsi20310 EPS contained a large number of functional groups such as -OH, -COOH and glycosidic bond. Some certain functional groups of Bsi20310 EPS changed being combined with Fe(III) hydrolysate. For instance, narrow peaks at 3429 and 1650 cm(-1) became wide; the peak at 2 921 cm(-1) weakened or disappeared; the peak at 1242 cm(-1) red-shifted slightly; peaks in the region of 1151-1038 cm(-1) became single and sharp, etc. The change in spectra indicated that -OH, -OOH and glycosidic bond might be the main functional groups. The study suggested a bright prospect of Bsi20310 EPS performing as an approach to safe and effective microbial coagulation enhancement.

Cleaning effectiveness and shaping ability of rotary ProTaper compared with rotary GT and manual K-Flexofile.

PURPOSE: To compare the cleaning efficacy and shaping ability of engine-driven ProTaper and GT files, and manual preparation using K-Flexofile instruments in curved root canals of extracted human teeth. METHODS: 45 canals of maxillary and mandibular molars with curvatures between 25 degrees and 40 degrees were divided into three groups. The groups were balanced with regard to the angle and the radius of canal curvature. Canals in each group were prepared to an apical size of 25 with either the rotary ProTaper or GT system, or manually with K-Flexofile using the modified double-flared technique. Irrigation was done with 2 mL 2.5% NaOCl after each instrument and, as the final rinse, 10 mL 2.5% NaOCl then 10 mL 17% EDTA and finally 5 mL distilled water. The double-exposure radiographic technique was used to examine for the presence of apical transportation. The time required to complete the preparation, as well as any change in working length after preparation were recorded. The roots were then grooved and split longitudinally. The amounts of debris and smear layer were evaluated at the apical, middle and coronal regions under the scanning electron microscope. Data were analyzed either parametrically with the F-test or non-parametrically using the Kruskal-Wallis test, where appropriate. RESULTS: Two GT files but none of the K-Flexofile and ProTaper instruments separated. For debris removal, the ProTaper group achieved a better result than GT (P < 0.05) but not the K-Flexofile group at all three regions (apical, middle and coronal). K-Flexofiles produced significantly less smear layer than ProTaper and GT files only in the middle third of the canal (P < 0.01). Both NiTi rotary instruments maintained the original canal shape better than the K-Flexofiles (P < 0.05) and required significantly less time to complete the preparation.