Comparative transcriptomic analysis reveals the molecular mechanism underlying seedling heterosis and its relationship with hybrid contemporary seeds DNA methylation in soybean.

Heterosis is widely used in crop production, but phenotypic dominance and its underlying causes in soybeans, a significant grain and oil crop, remain a crucial yet unexplored issue. Here, the phenotypes and transcriptome profiles of three inbred lines and their resulting F1 seedlings were analyzed. The results suggest that F1 seedlings with superior heterosis in leaf size and biomass exhibited a more extensive recompilation in their transcriptional network and activated a greater number of genes compared to the parental lines. Furthermore, the transcriptional reprogramming observed in the four hybrid combinations was primarily non-additive, with dominant effects being more prevalent. Enrichment analysis of sets of differentially expressed genes, coupled with a weighted gene co-expression network analysis, has shown that the emergence of heterosis in seedlings can be attributed to genes related to circadian rhythms, photosynthesis, and starch synthesis. In addition, we combined DNA methylation data from previous immature seeds and observed similar recompilation patterns between DNA methylation and gene expression. We also found significant correlations between methylation levels of gene region and gene expression levels, as well as the discovery of 12 hub genes that shared or conflicted with their remodeling patterns. This suggests that DNA methylation in contemporary hybrid seeds have an impact on both the F1 seedling phenotype and gene expression to some extent. In conclusion, our study provides valuable insights into the molecular mechanisms of heterosis in soybean seedlings and its practical implications for selecting superior soybean varieties.

Redox-Regulated Magnetic Conversions between Ferro- and Antiferromagnetism in Organic Nitroxide Diradicals.

Redox-induced magnetic transformation in organic diradicals is an appealing phenomenon. In this study, we theoretically designed twelve couples of diradicals in which two nitroxide (NO) radical groups are connected to the redox-active couplers including p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, hexacene-6,15-dione, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene. As evidenced at both the B3LYP and M06-2X levels of theory, the calculations reveal that the magnetic reversal can take place from ferromagnetism to antiferromagnetism, or vice versa, by means of redox method in these designed organic magnetic molecules. It was observed that p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, and hexacene-6,15-dione-bridged NO diradicals produce antiferromagnetism while their dihydrogenated counterparts exhibit ferromagnetism. Similarly, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene-bridged NO diradicals present ferromagnetism while their dihydrogenated counterparts show antiferromagnetism. The differences in the magnetic behaviors and magnetic magnitudes of each of the twelve couples of diradicals could be attributed to their distinctly different spin-interacting pathways. It was found that the nature of the coupler and the length of the coupling path are important factors in controlling the magnitude of the magnetic exchange coupling constant J. Specifically, smaller HOMO-LUMO (HOMO: highest occupied molecular orbital, LUMO: lowest unoccupied molecular orbital) gaps of the couplers and shorter coupler lengths, as well as shorter linking bond lengths, can attain stronger magnetic interactions. In addition, a diradical with an extensively π-conjugated structure is beneficial to spin transport and can effectively promote magnetic coupling, yielding a large |J| accordingly. That is, a larger spin polarization can give rise to a stronger magnetic interaction. The sign of J for these studied diradicals can be predicted from the spin alternation rule, the shape of the singly occupied molecular orbitals (SOMOs), and the SOMO-SOMO energy gaps of the triplet state. This study paves the way for the rational design of magnetic molecular switches.

Identifying Soybean Pod Borer (Leguminivora glycinivorella) Resistance QTLs and the Mechanism of Induced Defense Using Linkage Mapping and RNA-Seq Analysis.

The soybean pod borer (Leguminivora glycinivorella) (SPB) is a major cause of soybean (Glycine max L.) yield losses in northeast Asia, thus it is desirable to elucidate the resistance mechanisms involved in soybean response to the SPB. However, few studies have mapped SPB-resistant quantitative trait loci (QTLs) and deciphered the response mechanism in soybean. Here, we selected two soybean varieties, JY93 (SPB-resistant) and K6 (SPB-sensitive), to construct F2 and F2:3 populations for QTL mapping and collected pod shells before and after SPB larvae chewed on the two parents to perform RNA-Seq, which can identify stable QTLs and explore the response mechanism of soybean to the SPB. The results show that four QTLs underlying SPB damage to seeds were detected on chromosomes 4, 9, 13, and 15. Among them, qESP-9-1 was scanned in all environments, hence it can be considered a stable QTL. All QTLs explained 0.79 to 6.09% of the phenotypic variation. Meanwhile, 2298 and 3509 DEGs were identified for JY93 and K6, respectively, after the SPB attack, and most of these genes were upregulated. Gene Ontology enrichment results indicated that the SPB-induced and differently expressed genes in both parents are involved in biological processes such as wound response, signal transduction, immune response, and phytohormone pathways. Interestingly, secondary metabolic processes such as flavonoid synthesis were only significantly enriched in the upregulated genes of JY93 after SPB chewing compared with K6. Finally, we identified 18 candidate genes related to soybean pod borer resistance through the integration of QTL mapping and RNA-Seq analysis. Seven of these genes had similar expression patterns to the mapping parents in four additional soybean germplasm after feeding by the SPB. These results provide additional knowledge of the early response and induced defense mechanisms against the SPB in soybean, which could help in breeding SPB-resistant soybean accessions.

Heterosis and Differential DNA Methylation in Soybean Hybrids and Their Parental Lines.

Heterosis is an important biological phenomenon and is widely applied to increase agricultural productivity. However, the underlying molecular mechanisms of heterosis are still unclear. Here we constructed three combinations of reciprocal hybrids of soybean, and subsequently used MethylRAD-seq to detect CCGG and CCWGG (W = A or T) methylation in the whole genome of these hybrids and their parents at the middle development period of contemporary seed. We were able to prove that changes in DNA methylation patterns occurred in immature hybrid seeds and the parental variation was to some degree responsible for differential expression between the reciprocal hybrids. Non-additive differential methylation sites (DMSs) were also identified in large numbers in hybrids. Interestingly, most of these DMSs were hyper-methylated and were more concentrated in gene regions than the natural distribution of the methylated sites. Further analysis of the non-additive DMSs located in gene regions exhibited their participation in various biological processes, especially those related to transcriptional regulation and hormonal function. These results revealed DNA methylation reprogramming pattern in the hybrid soybean, which is associated with phenotypic variation and heterosis initiation.

Chemical conversion based on the crystal facet effect of transition metal oxides and construction methods for sharp-faced nanocrystals.

In-depth research has found that the nanocrystal facet of transition metal oxides (TMOs) greatly affects their heterogeneous catalytic performance, as well as the property of photocatalysis, gas sensing, electrochemical reaction, etc. that are all involved in chemical conversion processes. Therefore, the facet-dependent properties of TMO nanocrystals have been fully and carefully studied by combining systematic experiments and theoretical calculations, and mechanisms of chemical reactions are accurately explained at the molecular level, which will be closer to the essence of reactions. Evidently, as an accurate investigation on crystal facets, well-defined TMO nanocrystals are the basis and premise for obtaining relevant credible results, and shape-controlled synthesis of TMO nanocrystals thereby has received great attention and development. The success in understanding of facet-dependent properties and shape-controlled synthesis of TMO nanocrystals is highly valuable for the control of reaction and the design of high-efficiency TMO nanocrystal catalysts as well as other functional materials in practical applications.

Better immune efficacy triggered by the inactivated gI/gE-deleted pseudorabies virus with the additional insertion of gC gene in mice and weaned pigs.

A new variant of pseudorabies virus (PRV) with high pathogenicity has been prevalent in many swineherds vaccinated with Bartha-K61 in China since 2011. Several gene-deleted vaccine candidates have been developed based on new emerging PRV variants. PRV-AH, a new emerging PRV strain from Anhui Province, was isolated in our laboratory in 2013. In the present study, rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ were generated based on PRV-AH by homologous recombination. The growth kinetics of rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ were similar to their parental strains. Compared with the commercial inactivated vaccine of Ea strain, the immune efficacy of the inactivated vaccine based on recombinant viruses was evaluated in mice and weaned pigs. The result showed that the level of neutralizing antibody in mice immunized with rPRV-AH-gI-/gE-/gC+ was higher compared with those immunized with rPRV-AH-gI-/gE- at a dose of 106 TCID50 at 8 weeks post initial immunization (p < 0.0001). Among the groups immunized at a dose of 105 TCID50, the rPRV-AH-gI-/gE- group showed a survival rate of 37.5 %, while the rPRV-AH-gI-/gE-/gC+ group showed a protection rate of 87.5 % against the PRV-AH challenge. Besides, the rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ group immunized at a dose of 106 TCID50 showed a survival rate of 100 %. Interestingly, compared with the commercial vaccine group, the group of 105 TCID50 rPRV-AH-gI-/gE-/gC+ showed a lower level of neutralizing antibodies (p < 0.0001) but the same protection rate in mice. Moreover, in the pig experiment, the level of neutralizing antibodies in the group vaccinated with inactivated rPRV-AH-gI-/gE-/gC+ was higher than any other groups at 8 weeks post initial immunization (p < 0.05). More importantly, the milder symptoms and pathological lesions occurred in pigs vaccinated with rPRV-AH-gI-/gE-/gC+ after challenge with 106 TCID50 PRV-AH, revealing that additional insertion of gC gene could enhance the protective efficacy in PRV gI/gE-deleted vaccine in pigs. Collectively, these above-mentioned findings suggested that the inactivated vaccine of rPRV-AH-gI-/gE-/gC+ had a better immune efficacy, which could be regarded as a promising inactivated vaccine candidate for PRV control.

Neuroprotective Effects of Umbilical Cord-Derived Mesenchymal Stem Cells on Radiation-Induced Brain Injury in Mice.

OBJECTIVE: To investigate the neuroprotective effects of umbilical cord-derived mesenchymal stem cells (UC-MSCs) on radiation-induced brain injury (RIBI). METHODS: Thirty female C57BL/6 mice were randomly divided into three groups: control (CON), whole brain irradiation (WBI), and the cell therapy (MSC) group. Mice in the WBI and MSC groups received a single, whole brain irradiation treatment with 15 Gy of 60Co. Learning and memory were evaluated in the mice using the step-down avoidance test. The neuronal changes in the hippocampal cornu ammonis (CA) 1 region were observed using hematoxylin eosin (H&E) staining. The changes in astrocytes were visualized with glial fibrillary acidic protein immunohistochemistry, and the expression of TNF-α, IL-6, and IL-10 was detected by quantitative polymerase chain reaction (qPCR) along with Enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with mice in the WBI group, learning and memory in the MSC mice were significantly increased (P<0.05), neuronal degeneration and necrosis were significantly decreased (P<0.05), and the number of astrocytes was significantly increased (P<0.05). The levels of the in˙ammatory cytokines, TNF-α and IL-6, were significantly decreased (P<0.05), however, the inhibitory factor IL-10 was significantly increased (P<0.05). CONCLUSIONS: UC-MSCs play a neuroprotective role by inhibiting brain cell injury and neuroinflammation.

Facets Matching of Platinum and Ferric Oxide in Highly Efficient Catalyst Design for Low-Temperature CO Oxidation.

Rational design of supported noble metal is of great importance for highly efficient heterogeneous catalysts. On the basis of the distinct adsorption characteristics of noble metal and transition-metal oxides toward O2 and CO, the overall catalytic performance of CO oxidation reaction could be further modified by controlling the surface property of the materials to achieve optimal adsorption activity. Here, we studied the influence of facets matching between both platinum and ferric oxide support on CO conversion efficiency. It shows that the activities of four catalysts rank following the order of Pt{100}/α-Fe2O3{104} > Pt{100}/α-Fe2O3{001} > Pt{111}/α-Fe2O3{001} > Pt{111}/α-Fe2O3{104}. The strong metal-support interaction and adsorption energy varying with matched enclosed surface are demonstrated by density functional theory based on the projected d-band density of states. Compared with the other three cases, the combination of Pt{100} and α-Fe2O3{104} successfully weakens CO poisoning and provides proper active sites for O2 adsorption. It reveals that the facets matching could be a practicable approach to design catalysts with enhanced catalytic performance.

Mapping QTLs for pre-harvest sprouting tolerance on chromosome 2D in a synthetic hexaploid wheat x common wheat cross.

Based on segregation distortion of simple sequence repeat (SSR) molecular markers, we detected a significant quantitative trait loci (QTL) for pre-harvest sprouting (PHS) tolerance on the short arm of chromosome 2D (2DS) in the extremely susceptible population of F2 progeny generated from the cross of PHS tolerant synthetic hexaploid wheat cultivar 'RSP' and PHS susceptible bread wheat cultivar '88-1643'. To identify the QTL of PHS tolerance, we constructed two SSR-based genetic maps of 2DS in 2004 and 2005. One putative QTL associated with PHS tolerance, designated Qphs.sau-2D, was identified within the marker intervals Xgwm261-Xgwm484 in 2004 and in the next year, nearly in the same position, between markers wmc112 and Xgwm484. Confidence intervals based on the LOD-drop-off method ranged from 9 cM to 15.4 cM and almost completely overlapped with marker interval Xgwm261-Xgwm484. Flanking markers near this QTL could be assigned to the C-2DS1-0.33 chromosome bin, suggesting that the gene(s) controlling PHS tolerance is located in that chromosome region. The phenotypic variation explained by this QTL was about 25.73-27.50%. Genotyping of 48 F6 PHS tolerant plants derived from the cross between PHS tolerant wheat cultivar 'RSP' and PHS susceptible bread wheat cultivar 'MY11' showed that the allele of Qphs.sau-2D found in the 'RSP' genome may prove useful for the improvement of PHS tolerance.

[Characterization and diagnostic accuracy of serous cystadenomas and mucinous neoplasms of the pancreas with multi-slice helical computed tomography].

OBJECTIVE: To evaluate the feasibility of using multi-slice helical computed tomography (MS-CT) to accurately distinguish serous cystadenomas from mucinous cystadenomas or cystadenocarcinomas of the pancreas and to determine their radiographic appearances that can be applied for differentiative diagnosis. METHODS: We performed a single-blind retrospective analysis of CT images of 30 patients with pathologically proven primary cystic pancreatic neoplasms (12 cases of serous cystadenomas, 14 cases of mucinous cystadenomas, and 4 cases of mucinous cystadenocarcinomas) to reach a diagnosis of either serous cystadenoma or mucinous cystic tumor. CT features such as tumor location, septations, presence of calcification, features of cystic wall, papillary excrescences, and size of the largest cyst were recorded. Statistical analysis was performed to evaluate the efficacy of certain CT findings in the differentiation of serous cystadenomas and mucinous neoplasms. RESULTS: Totally 9 (75.0%) serous cystadenomas and 16 (88.9%) mucinous tumors were correctly diagnosed. Three serous cystadenomas were misdiagnosed as mucinous cystadenomas, while 2 mucinous neoplasms were misdiagnosed as serous cystadenomas. And 9 (75.0%) serous cystadenomas were located at the pancreatic head and neck areas, while 12 (66.7%) mucinous neoplasms were located at the pancreatic body and tail areas (P < 0.05). The presence of calcification, especially central calcification, had statistical significance in differentiating serous cystadenoma from mucinous neoplasms (P < 0.05). The size of the largest cyst over 2 cm was positive associated with mucinous neoplasms (P < 0.05). CONCLUSION: CT characteristics between serous cystadenomas and mucinous neoplasms of the pancreas have distinct difference, which validates the values of CT in differentiating these tumors. However, atypical CT appearances may compromise its diagnostic accuracy.