The synthesis of a series of 1,2‐diamino‐o‐carboranes (1–4) is reported. The molecular structures of these diamino‐o‐carboranes are remarkable as the inner‐cluster C−C bonds are all ultra‐long ...(162.7–193.1 pm) and vary substantially with small variations in the substituents. The results of quantum mechanical investigations suggest that the origin of the bond elongation is significant in‐plane negative hyperconjugation of lone pairs of the nitrogen substituents with the σ* orbitals of the C−C bonds in o‐carboranes.
Breaking the law: A series of 1,2‐diamino‐o‐carboranes with exceptionally long C−C bonds (up to 193 pm) were synthesized. The origin of this bond elongation was attributed to the in‐plane negative hyperconjugation between the lone pairs of the nitrogen atoms and the σ*C−C orbital in the o‐carborane.
miRNAs contribute to plant resistance against pathogens. Previously, we found that the function of miR398b in immunity in rice differs from that in Arabidopsis. However, the underlying mechanisms are ...unclear. In this study, we characterized the mutants of miR398b target genes and demonstrated that multiple superoxide dismutase genes contribute to miR398b-regulated rice immunity against the blast fungus Magnaporthe oryzae. Out of the four target genes of miR398b, mutations in Cu/Zn-Superoxidase Dismutase1 (CSD1), CSD2 and Os11g09780 (Superoxide DismutaseX, SODX) led to enhanced resistance to M. oryzae and increased hydrogen peroxide (H
O
) accumulation. By contrast, mutations in Copper Chaperone for Superoxide Dismutase (CCSD) resulted in enhanced susceptibility. Biochemical studies revealed that csd1, csd2 and sodx displayed altered expression of CSDs and other superoxide dismutase (SOD) family members, leading to increased total SOD enzyme activity that positively contributed to higher H
O
production. By contrast, the ccsd mutant showed CSD protein deletion, resulting in decreased CSD and total SOD enzyme activity. Our results demonstrate the roles of different SODs in miR398b-regulated resistance to rice blast disease, and uncover an integrative regulatory network in which miR398b boosts total SOD activity to upregulate H
O
concentration and thereby improve disease resistance.
miRNAs contribute to plant resistance against pathogens. Previously, we found that the function of miR398b in immunity in rice differs from that in Arabidopsis. However, the underlying mechanisms are ...unclear.
In this study, we characterized the mutants of miR398b target genes and demonstrated that multiple superoxide dismutase genes contribute to miR398b-regulated rice immunity against the blast fungus Magnaporthe oryzae.
Out of the four target genes of miR398b, mutations in Cu/Zn-Superoxidase Dismutase1 (CSD1), CSD2 and Os11g09780 (Superoxide DismutaseX, SODX) led to enhanced resistance to M. oryzae and increased hydrogen peroxide (H₂O₂) accumulation. By contrast, mutations in Copper Chaperone for Superoxide Dismutase (CCSD) resulted in enhanced susceptibility. Biochemical studies revealed that csd1, csd2 and sodx displayed altered expression of CSDs and other superoxide dismutase (SOD) family members, leading to increased total SOD enzyme activity that positively contributed to higher H₂O₂ production. By contrast, the ccsd mutant showed CSD protein deletion, resulting in decreased CSD and total SOD enzyme activity.
Our results demonstrate the roles of different SODs in miR398b-regulated resistance to rice blast disease, and uncover an integrative regulatory network in which miR398b boosts total SOD activity to upregulate H₂O₂ concentration and thereby improve disease resistance.
We report the results of our systematic survey for Galactic 6.7 GHz Class II CH3OH maser emission toward a sample of young stellar objects. The survey was conducted with the Shanghai Tianma Radio ...Telescope (TMRT). The sample consists of 3348 sources selected from the all-sky Wide-field Infrared Survey Explorer (WISE) point-source catalog. We discussed the selection criteria in detail and the detection results of those at high Galactic latitudes (i.e., ) in a previous paper (Yang et al. 2017). Here, we present the results from the survey of those at low Galactic latitudes, i.e., . Of 1875 selected WISE point sources, 291 positions that were actually associated with 224 sources that were detected with CH3OH maser emission. Among them, 32 are newly detected. A majority of the newly detected sources are associated with bright WISE sources. The majority of the detected sources (209/224 = 93.3%) are quite close to the Galactic Plane ( ) and lie on the inner spiral arms with positive local standard of rest velocities. The detection rate and the color-color distribution of our detection are all matched with our anticipation. Combining with detections from previous surveys, we compile a catalog of 1085 sources with 6.7 GHz CH3OH maser emission in our Galaxy.
Patterns of hepatitis B virus reactivation (HBV‐R) in HBsAg (−)/HBcAb (+) patients with B‐cell non‐Hodgkin lymphoma (NHL) receiving rituximab based immunochemotherapy have not been well described. ...The retrospective study included 222 HBsAg (−)/HBcAb (+) NHL patients as training cohort and 127 cases as validation cohort. The incidence of HBV‐R in HBsAg (−)/HBcAb (+) B‐cell NHL patients was 6.3% (14/222), of which that in HBsAg (−)/HBsAb (−)/HBeAg (−)/HBeAb (+)/HBcAb (+) population was 23.7% (9/38). Multivariate analysis showed that HBsAg (‐)/HBsAb (−)/HBeAg (−)/HBeAb (+)/HBcAb (+) correlated with a high risk of HBV‐R in B‐cell lymphoma patients (training phase hazard ratio HR, 10.123; 95% confidence interval CI, 3.389–30.239; p < 0.001; validation phase HR, 18.619; 95% CI, 1.684–205.906; p = 0.017; combined HR, 12.264; 95% CI, 4.529–33.207; p < 0.001). In the training cohort, the mortality rate of HBsAg (−)/HBcAb (+) B‐cell NHL caused by HBV‐R was 14.3% (2/14) while that for HBV reactivated HBsAg (‐)/HBsAb (−)/HBeAg (−)/HBeAb (+)/HBcAb (+) population was up to 44.4% (4/9). As a high incidence of HBV‐R and high mortality after HBV‐R was found in HBsAg (−)/HBsAb (−)/HBcAb (+)/HBeAg (−)/HBeAb (+) patients with B‐cell NHL receiving rituximab based immunochemotherapy, prophylactic antiviral therapy is recommended for these patients.
Summary
Rice false smut has emerged as a serious grain disease in rice production worldwide. The disease is characterized by the transformation of individual rice florets into false smut balls, which ...is caused by the fungal pathogen Ustilaginoidea virens. To date, little is known about the host factors required for false smut ball formation by U. virens. In this study, we identified histological determinants for the formation of false smut balls by inoculating U. virens into rice floral mutants defective with respect to individual floral parts. The results showed that U. virens could form mature false smut balls in rice floral mutants with defective pistils, but failed to develop false smut balls in the superwoman mutant lacking stamens, identifying that U. virens requires rice stamens to complete its infection cycle. Comparative transcriptome analysis indicated a list of candidate host genes that may facilitate nutrient acquisition by U. virens from the rice stamens, such as SWEET11, SWEET14 and SUT5, and genes involved in the biosynthesis of trehalose and raffinose family sugars. These data pinpoint rice stamens as the key target organ of U. virens infection and provide a valuable starting point for dissecting the molecular mechanism of false smut ball formation.
Abstract
Construction of white‐light emitters is of great importance in practical applications but is challenging for metal nanoclusters. Herein, arginine (Arg)‐mediated copper nanoclusters (Cu NCs) ...assemblies with white‐light emission (WLE) are reported for the first time. The multidentate ligand, Arg, not only effectively tailors the high stability and locally‐excited emission (LES) of aqueous phase Cu NCs, but also bridges 1‐naphthalenol methylcarbamate (NMC) to generate a blue emitter via through‐space interactions (TSIs), resulting in a stable mixed light. Density functional theory calculation and mass spectrum further confirm that Arg can allow for the formation of strong hydrogen‐bonds with the ligand 2,4‐diaminotoluene of Cu NCs, and formation of TSIs‐based complexes with NMC. More importantly, pure white‐light emission (WLE) with Commission Internationale de L’Eclairagecoordination (0.30, 0.31) is observed by regulating the ratio between Arg and the interfacial ligand of NMC. The findings not only provide a new perspective for the construction of WLE emitters via interface modification chemistry but also open a window to gain insight into the mechanism of interface engineering.
The selection of native greening plants to improve rural greening technology is crucial for enriching methods of building rural plant landscapes. However, there are few studies from the perspective ...of visual preference using quantitative methods. By using eye-tracking technology, this study studies students in the Central South University of Forestry and Technology and villagers in Changkou Village, Fujian Province, employing pictures of plant organs-leaves, flowers, and fruits-as stimulating materials to analyze five indicators: the total duration of fixations, the number of fixations, average duration of fixations, average pupil size and average amplitude of saccades. A number of findings came from this research First, people visually prefer leaves, followed by flowers and fruits. In terms of species, Photinia × fraseri, Metasequoia glyptostroboides, Photinia serratifolia, Cunninghamia lanceolata and Koelreuteria bipinnata have higher overall preference. Families such as Malvaceae, Fabaceae, Araliaceae, Myricaceae and Cupressaceae have stronger visual attraction than others. Second, there are distinct differences in the preference of shapes and textures of leaves: aciculiform, strip, cordiform, sector and jacket-shape are more attractive; leather-like leaves have a higher visual preference than paper-like leaves; different colors and whether leaves are cracked or not have little effect on leaf observation. Third, the preference for flowers with different inflorescence and colors is significant. Capitulum, cymes and panicles are more attractive; purple is the most preferred color, followed by white, yellow and red. Finally, there are significant differences in preferences for fruit characteristics, with medium-sized fruits and black fruits preferred, while kidney-shaped and spoon-shaped fruits are considered more attractive. Pomes, pods, samaras, and berries have received relatively more attention.
Probiotic could be a promising alternative to antibiotics for the prevention of enteric infections; however, further information on the dose effects is required. In this study, weanling piglets were ...orally administered low- or high-dose Lactobacillus rhamnosus ACTT 7469 (10(10) CFU/d or 10(12) CFU/d) for 1 week before F4 (K88)-positive Escherichia coli challenge. The compositions of faecal and gastrointestinal microbiota were recorded; gene expression in the intestines was assessed by real-time PCR; serum tumour necrosis factor-α (TNF-α) concentrations and intestinal Toll-like receptor 4 (TLR4) were detected by ELISA and immunohistochemistry, respectively. Unexpectedly, high-dose administration increased the incidence of diarrhoea before F4(+)ETEC challenge, despite the fact that both doses ameliorated F4(+)ETEC-induced diarrhoea with increased Lactobacillus and Bifidobacterium counts accompanied by reduced coliform shedding in faeces. Interestingly, L. rhamnosus administration reduced Lactobacillus and Bifidobacterium counts in the colonic contents, and the high-dose piglets also had lower Lactobacillius and Bacteroides counts in the ileal contents. An increase in the concentration of serum TNF-α induced by F4(+)ETEC was observed, but the increase was delayed by L. rhamnosus. In piglets exposed to F4(+)ETEC, jejunal TLR4 expression increased at the mRNA and protein levels, while jejunal interleukin (IL)-8 and ileal porcine β-defensins 2 (pBD2) mRNA expression increased; however, these increases were attenuated by administration of L. rhamnosus. Notably, expression of jejunal TLR2, ileal TLR9, Nod-like receptor NOD1 and TNF-α mRNA was upregulated in the low-dose piglets after F4(+)ETEC challenge, but not in the high-dose piglets. These findings indicate that pretreatment with a low dose of L. rhamnosus might be more effective than a high dose at ameliorating diarrhoea. There is a risk that high-dose L. rhamnosus pretreatment may negate the preventative effects, thus decreasing the prophylactic benefits against potential enteric pathogens. Our data suggest a safe threshold for preventative use of probiotics in clinical practice.
Catalase‐peroxidase is a heme oxidoreductase widely distributed in bacteria and lower eukaryotes. In this study, we identified a catalase‐peroxidase PiCP1 (PITG_05579) in Phytophthora infestans. ...PiCP1 had catalase/peroxidase and secretion activities and was highly expressed in sporangia and upregulated in response to oxidative and heat stresses. Compared with wild type, PiCP1‐silenced transformants (STs) had decreased catalase activity, reduced oxidant stress resistance and damped cell wall integrity. In contrast, PiCP1‐overexpression transformants (OTs) demonstrated increased tolerance to abiotic stresses and induced the upregulation of PR genes in the host salicylic acid pathway. The high concentration of PiCP1 can also induced callose deposition in plant tissue. Importantly, both STs and OTs have severely reduced sporangia formation and zoospore releasing rate, but the sporangia germination rate and type varied depending on environmental conditions. Comparative sequence analyses show that catalase‐peroxidases are broadly distributed and highly conserved among soil–borne plant parasitic oomycetes, but not in freshwater‐inhabiting or strictly plants‐inhabiting oomycetes. In addition, we found that silencing PiCP1 downregulated the expression of PiCAT2. These results revealed the important roles of PiCP1 in abiotic stress resistance, pathogenicity and in regulating asexual structure development in response to environmental change. Our findings provide new insights into catalase‐peroxidase functions in eukaryotic pathogens.
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