PeNAC67-PeKAN2-PeSCL23 and B-class MADS-box transcription factors synergistically regulate the specialization process from petal to lip in Phalaenopsis equestris

The molecular basis of orchid flower development involves a specific regulatory program in which MADS-box transcription factors play a central role. The recent 'perianth code' model hypothesizes that two types of higher-order heterotetrameric complexes, namely SP complex and L complex, play pivotal roles in the orchid perianth organ formation. Therefore, we explored their roles and searched for other components of the regulatory network.Through the combined analysis for transposase-accessible chromatin with high-throughput sequencing and RNA sequencing of the lip-like petal and lip from Phalaenopsis equestris var.trilip, transcription factor-(TF) genes involved in lip development were revealed. PeNAC67 encoding a NAC-type TF and PeSCL23 encoding a GRAS-type TF were differentially expressed between the lip-like petal and the lip. PeNAC67 interacted with and stabilized PeMADS3, which positively regulated the development of lip-like petal to lip. PeSCL23 and PeNAC67 competitively bound with PeKAN2 and positively regulated the development of lip-like petal to petal by affecting the level of PeMADS3. PeKAN2 as an important TF that interacts with PeMADS3 and PeMADS9 can promote lip development. These results extend the 'perianth code' model and shed light on the complex regulation of orchid flower development.

Mechanism underlying the rapid growth of Phalaenopsis equestris induced by 60Co-γ-ray irradiation

Gamma (γ)-ray irradiation is one of the important modern breeding methods. Gamma-ray irradiation can affect the growth rate and other characteristics of plants. Plant growth rate is crucial for plants. In horticultural crops, the growth rate of plants is closely related to the growth of leaves and flowering time, both of which have important ornamental value. In this study, 60Co-γ-ray was used to treat P. equestris plants. After irradiation, the plant's leaf growth rate increased, and sugar content and antioxidant enzyme activity increased. Therefore, we used RNA-seq technology to analyze the differential gene expression and pathways of control leaves and irradiated leaves. Through transcriptome analysis, we investigated the reasons for the rapid growth of P. equestris leaves after irradiation. In the analysis, genes related to cell wall relaxation and glucose metabolism showed differential expression. In addition, the expression level of genes encoding ROS scavenging enzyme synthesis regulatory genes increased after irradiation. We identified two genes related to P. equestris leaf growth using VIGS technology: PeNGA and PeEXPA10. The expression of PeEXPA10, a gene related to cell wall expansion, was down-regulated, cell wall expansion ability decreased, cell size decreased, and leaf growth rate slowed down. The TCP-NGATHA (NGA) molecular regulatory module plays a crucial role in cell proliferation. When the expression of the PeNGA gene decreases, the leaf growth rate increases, and the number of cells increases. After irradiation, PeNGA and PeEXPA10 affect the growth of P. equestris leaves by influencing cell proliferation and cell expansion, respectively. In addition, many genes in the plant hormone signaling pathway show differential expression after irradiation, indicating the crucial role of plant hormones in plant leaf growth. This provides a theoretical basis for future research on leaf development and biological breeding.

Function of two splicing variants of RcCPR5 in the resistance of Rosa chinensis to powdery mildew

Rosa chinensis is an important economic and ornamental crop, but powdery mildew greatly reduces its ornamental and economic value. The RcCPR5 gene, encoding a constitutive expressor of pathogenesis-related genes, has two splicing variants in R. chinensis. Compared with RcCPR5-1, RcCPR5-2 has a large C-terminal deletion. During disease development, RcCPR5-2 responded quickly and coordinated with RcCPR5-1 to resist the invasion of the powdery mildew pathogen. In virus-induced gene silencing experiments, down-regulation of RcCPR5 improved the resistance of R. chinensis to powdery mildew. This was confirmed to be broad-spectrum resistance. In the absence of pathogen infection, RcCPR5-1 and RcCPR5-2 formed homodimers and heterodimers to regulate plant growth; but when infected by the powdery mildew pathogen, the RcCPR5-1 and RcCPR5-2 complexes disassociated and released RcSIM/RcSMR to induce effector-triggered immunity, thereby inducing resistance to pathogen infection.

Multifaceted roles of LhWRKY44 in promoting anthocyanin accumulation in Asiatic hybrid lilies (Lilium spp.)

The Asiatic hybrid lily (Lilium spp.) is a horticultural crop with high commercial value and diverse anthocyanin pigmentation patterns. However, the regulatory mechanism underlying lily flower color has been largely unexplored. Here, we identified a WRKY transcription factor from lily tepals, LhWRKY44, whose expression was closely associated with anthocyanin accumulation. Functional verification indicated that LhWRKY44 positively regulated anthocyanin accumulation. LhWRKY44 physically interacted with LhMYBSPLATTER and directly bound to the LhMYBSPLATTER promoter, which enhanced the effect of the LhMYBSPLATTER-LhbHLH2 MBW complex activator on anthocyanin accumulation. Moreover, EMSA and dual-luciferase assays revealed that LhWRKY44 activated and bound to the promoters of gene LhF3H and the intracellular anthocyanin-related glutathione S-transferase gene LhGST. Interestingly, our further results showed that LhWRKY44 participated in light and drought-induced anthocyanin accumulation, and improved the drought tolerance in lily via activating stress-related genes. These results generated a multifaceted regulatory mechanism for the LhWRKY44-meditaed enhancement by the environmental signal pathway of anthocyanin accumulation and expanded our understanding of the WRKY-mediated transcriptional regulatory hierarchy modulating anthocyanin accumulation in Asiatic hybrid lilies.

Polarized tip-enhanced Raman spectroscopy at liquid He temperature in ultrahigh vacuum using an off-axis parabolic mirror

Tip-enhanced Raman spectroscopy (TERS) combines inelastic light scattering well below the diffraction limit down to the nanometer range and scanning probe microscopy and, possibly, spectroscopy. In this way, topographic and spectroscopic as well as single- and two-particle information may simultaneously be collected. While single molecules can now be studied successfully, bulk solids are still not meaningfully accessible. It is the purpose of the work presented here to outline approaches toward this objective. We describe a home-built, liquid helium cooled, ultrahigh vacuum TERS. The setup is based on a scanning tunneling microscope and, as an innovation, an off-axis parabolic mirror having a high numerical aperture of ∼0.85 and a large working distance. The system is equipped with a fast load-lock chamber, a chamber for the in situ preparation of tips, substrates, and samples, and a TERS chamber. Base pressure and temperature in the TERS chamber were ∼3 × 10-11 mbar and 15 K, respectively. Polarization dependent tip-enhanced Raman spectra of the vibration modes of carbon nanotubes were successfully acquired at cryogenic temperature. The new features described here including very low pressure and temperature and the external access to the light polarizations, thus the selection rules, may pave the way toward the investigation of bulk and surface materials.

The MYB transcription factor RcMYB1 plays a central role in rose anthocyanin biosynthesis

Rose (Rosa hybrida) is one of most famous ornamental plants in the world, and its commodity value largely depends on its flower color. However, the regulatory mechanism underlying rose flower color is still unclear. In this study, we found that a key R2R3-MYB transcription factor, RcMYB1, plays a central role in rose anthocyanin biosynthesis. Overexpression of RcMYB1 significantly promoted anthocyanin accumulation in both white rose petals and tobacco leaves. In 35S:RcMYB1 transgenic lines, a significant accumulation of anthocyanins occurred in leaves and petioles. We further identified two MBW complexes (RcMYB1-RcBHLH42-RcTTG1; RcMYB1-RcEGL1-RcTTG1) associated with anthocyanin accumulation. Yeast one-hybrid and luciferase assays showed that RcMYB1 could active its own gene promoter and those of other EBGs (early anthocyanin biosynthesis genes) and LBGs (late anthocyanin biosynthesis genes). In addition, both of the MBW complexes enhanced the transcriptional activity of RcMYB1 and LBGs. Interestingly, our results also indicate that RcMYB1 is involved in the metabolic regulation of carotenoids and volatile aroma. In summary, we found that RcMYB1 widely participates in the transcriptional regulation of ABGs (anthocyanin biosynthesis genes), indicative of its central role in the regulation of anthocyanin accumulation in rose. Our results provide a theoretical basis for the further improvement of the flower color trait in rose by breeding or genetic modification.

PeGRF6-PeGIF1 complex regulates cell proliferation in the leaf of Phalaenopsis equestris

Phalaenopsis equestris is an ornamental plant with very large leaves. In this study, we identified genes related to the regulation of leaf development in Phalaenopsis and explored their mechanism of action. Sequence alignment and phylogenetic analyses revealed that PeGRF6 in the PeGRF family of P. equestris has similarities with the Arabidopsis genes AtGRF1 and AtGRF2, which are known to be involved in the regulation of leaf development. Among the PeGRFs, PeGRF6 was continuously and stably expressed at various stages of leaf development. The functions of PeGRF6 and of its complex formed with PeGIF1 in leaf development were verified by virus-induced gene silencing (VIGS) technology. The results show that the PeGRF6-PeGIF1 complex forms in the nucleus and positively regulates leaf cell proliferation via influencing cell size. Interestingly, VIGS suppression of PeGRF6 resulted in anthocyanin accumulation in Phalaenopsis leaves. Analyses of the regulatory mechanism of the miR396-PeGRF6 model based on the P. equestris small RNA library constructed here suggested that PeGRF6 transcripts are cleaved by Peq-miR396. These results show that, compared with PeGRF6 or PeGIF1 alone, the PeGRF6-PeGIF1 complex plays a more important role in the leaf development of Phalaenopsis, possibly by regulating the expression of cell cycle-related genes.

New insights into the influence of NHX-type Cation/H+ antiporter on flower color in Phalaenopsis orchids

Vacuolar sodium/proton Na⁺(K⁺)/H⁺ exchanger (NHX) influence color formation because of their effects on cellular pH and Na⁺/K⁺ homeostasis. Research regarding NHXs has mainly focused on the vacuolar NHX family members. However, the NHX functions related to Phalaenopsis flower coloration remain relatively uncharacterized. In this study, we cloned and characterized PeNHX1, a vacuolar cation/H⁺ antiporter-encoding gene that is highly expressed in the Phalaenopsis equestris (orchid) flower lip. Phylogenetic and sequence analyses showed that PeNHX1 is a vacuolar NHX protein family member that is similar to other known vacuolar antiporters. The PeNHX1-GFP fusion protein was clearly localized to the vacuolar membrane in a transient transfection assay. A quantitative real-time PCR analysis revealed the increased expression of PeNHX1 in different flower developmental stages. Moreover, it was more highly expressed in the lip than in the other flower organs. On the basis of virus-induced gene silencing, we determined that decreased PeNHX1 expression significantly reduces P. equestris petal coloration. Furthermore, the overexpression of PeNHX1 in Phalaenopsis Big Chili caused the pH to increase and the petal color to change from red to blue. The results indicate that NHX1 may mediates the Na ⁺ or K⁺/H⁺ exchange, thereby regulating the vacuolar pH to promote blue coloration. This research provides a theoretical basis for the development of orchid varieties with blue flowers.

WUSCHEL-related homeobox genes cooperate with cytokinin to promote bulbil formation in Lilium lancifolium

The bulbil is an important vegetative reproductive organ in triploid tiger lily (Lilium lancifolium). Based on our previously obtained transcriptome data, we screened two WUSCHEL-related homeobox (WOX) genes closely related to bulbil formation, LlWOX9 and LlWOX11. However, the biological functions and regulatory mechanisms of LlWOX9 and LlWOX11 are unclear. In this study, we cloned the full-length coding sequences of LlWOX9 and LlWOX11. Transgenic Arabidopsis (Arabidopsis thaliana) showed increased branch numbers, and the overexpression of LlWOX9 and LlWOX11 in stem segments promoted bulbil formation, while the silencing of LlWOX9 and LlWOX11 inhibited bulbil formation, indicating that LlWOX9 and LlWOX11 are positive regulators of bulbil formation. Cytokinin type-B response regulators could bind to the promoters of LlWOX9 and LlWOX11 and promote their transcription. LlWOX11 could enhance cytokinin pathway signaling by inhibiting the transcription of type-A LlRR9. Our study enriches the understanding of the regulation of plant development by the WOX gene family and lays a foundation for further research on the molecular mechanism of bulbil formation in lily.

Analysing neutron radiation damage in YBa2 Cu3 O7-x high temperature superconductor tapes

Superconducting windings will be necessary in future fusion reactors to generate the strong magnetic fields needed to confine the plasma, and these superconducting materials will inevitably be exposed to neutron damage. It is known that this exposure results in the creation of isolated damage cascades, but the presence of these defects alone is not sufficient to explain the degradation of macroscopic superconducting properties and a quantitative method is needed to assess the subtle lattice damage in between the clusters. We have studied REBCO coated conductors irradiated with neutrons to a cumulative dose of 3.3×10²²  n*m^-2  that show a degradation of both T_c  and J_c values, and use HRTEM analysis to show that this irradiation introduces ∼10 nm amorphous collision cascades. In addition we introduce a new method for the analysis of these images to quantify the degree of lattice disorder in the apparently perfect matrix between these cascades. This method utilises Fast Fourier and Discrete Cosine Transformations of a statistically-relevant number of HRTEM images of pristine, neutron-irradiated, and amorphous samples, and extracts the degree of randomness in terms of entropy values. Our results show that these entropy values in both mid-frequency band FFT and DCT domains correlate with the expected level of lattice damage, with the pristine samples having the lowest and the fully amorphous regions the highest entropy values.  Our methodology allows us to quantify 'invisible' lattice damage to and correlate these values to the degradation of superconducting properties, and also has relevance for a wider range of applications in the field of electron microscopy where small changes in lattice perfection need to be measured. This article is protected by copyright. All rights reserved.

Construction of yeast one-hybrid library and screening of transcription factors regulating LhMYBSPLATTER expression in Asiatic hybrid lilies (Lilium spp.)

BACKGROUND

Anthocyanins, which belong to flavonoids, are widely colored among red-purple pigments in the Asiatic hybrid lilies (Lilium spp.). Transcription factor (TF) LhMYBSPLATTER (formerly known as LhMYB12-Lat), identified as the major kernel protein, regulating the anthocyanin biosynthesis pathway in 'Tiny Padhye' of Tango Series cultivars, which the pigmentation density is high in the lower half of tepals and this patterning is of exceptional ornamental value. However, the research on mechanism of regulating the spatial and temporal expression differences of LhMYBSPLATTER, which belongs to the R2R3-MYB subfamily, is still not well established. To explore the molecular mechanism of directly related regulatory proteins of LhMYBSPLATTER in the anthocyanin pigmentation, the yeast one-hybrid (Y1H) cDNA library was constructed and characterized.

RESULTS

In this study, we describe a yeast one-hybrid library to screen transcription factors that regulate LhMYBSPLATTER gene expression in Lilium, with the library recombinant efficiency of over 98%. The lengths of inserted fragments ranged from 400 to 2000 bp, and the library capacity reached 1.6 × 10⁶ CFU of cDNA insert, which is suitable to fulfill subsequent screening. Finally, seven prey proteins, including BTF3, MYB4, IAA6-like, ERF4, ARR1, ERF WIN1-like, and ERF061 were screened by the recombinant bait plasmid and verified by interaction with the LhMYBSPLATTER promoter. Among them, ERFs, AUX/IAA, and BTF3 may participate in the negative regulation of the anthocyanin biosynthesis pathway in Lilium.

CONCLUSION

A yeast one-hybrid library of lily was successfully constructed in the tepals for the first time. Seven candidate TFs of LhMYBSPLATTER were screened, which may provide a theoretical basis for the study of floral pigmentation.

[Mn2+-doped Prussian blue nanoparticles for T1-T2 dual-mode magnetic resonance imaging and photothermal therapy in vitro]

OBJECTIVE

To prepare Mn²⁺-doped Prussian blue nanoparticles (Mn-PB NPs) for T1-T2 dual-mode magnetic resonance imaging (MRI) and photothermal therapy in vitro.

OBJECTIVE

Mn-PB NPs were prepared based on manganese chloride, ferrous chloride and potassium ferricyanide using the microemulsion method. The performance of T1-T2 dual-mode MRI with Mn-PB NPs and the photothermal property of the nanoparticles were assessed. CCK-8 assay and AM/PI double staining were used to evaluate the effect of photothermal therapy in vitro using the parepared nanoparticles.

OBJECTIVE

The prepared Mn-PB NPs had a mean particle size of 39.46±0.42 nm with a Zeta potential of -25.9±1.2 mV and exhibited a good dispersibility and uniform particle size. In MRI using the nanoparticles, the r1 and r2 values reached 0.68 and 3.65 (mmol/L)^-1s^-1, respectively, indicating good performance of Mn-PB NPs for T1 and T2 enhancement in MRI. When irradiated with 808 nm laser for 10 min, Mn-PB NPs showed a temperature rise to 90 ℃ to cause significant reduction of cell survival. CCK-8 assay and AM/PI double staining confirmed that Mn-PB NPs were capable of efficient killing of HepG2 cells upon 808 nm laser irradiation.

OBJECTIVE

The Mn-PB NPs prepared in this work have uniform particle size and show good performances both in MRI for T1 and T2 enhancement and in photothermal therapy in vitro without obvious cytotoxicity.

Histological analysis of spermatogenesis and the germ cell seasonal development within the testis of domesticated tree shrews (Tupaia belangeri chinensis)

This study aimed to address the lack of information on the male germ cell seasonal development of domesticated tree shrews (Tupaia belangeri chinensis). Testicular tissues were collected from 60 tree shrews (n=5 per month). The ultrastructures of the testes and spermatids were examined via transmission electron microscopy. Apoptosis of spermatogenic cells was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The expression of proliferation factors, namely, proliferating cell nuclear antigen (PCNA) and Ki67, in testicular tissues was assayed through immunohistochemistry. Spermatids ultrastructure showed seasonal differences, and spermatogenesis was relatively active in June and July and relatively stagnant from October to November. The percentage of TUNEL-positive germ cells was less during October and November, while greater in July than other phases. The number of PCNA-nucleus-positive germ cells was most in June and July, but with cytoplasm staining from October to November. Ki67 presented positive expression in the testes from April to September, with highest expression in June, but with no expression from October to March. In summary, there are seasonal differences in tissue morphology related to spermatogenesis in domesticated tree shrews. PCNA expression and Ki67 expression are good indicators of seasonal differences in male germ cells.

Cytokinin Type-B Response Regulators Promote Bulbil Initiation in Lilium lancifolium

The bulbil is an important vegetative reproductive organ in triploid Lilium lancifolium whose development is promoted by cytokinins. Type-B response regulators (RRs) are critical regulators that mediate primary cytokinin responses and promote cytokinin-induced gene expression. However, the function of cytokinin type-B Arabidopsis RRs (ARRs) in regulating bulbil formation is unclear. In this study, we identified five type-B LlRRs, LlRR1, LlRR2, LlRR10, LlRR11 and LlRR12, in L. lancifolium for the first time. The five LlRRs encode proteins of 715, 675, 573, 582 and 647 amino acids. All of the regulators belong to the B-I subfamily, whose members typically contain a conserved CheY-homologous receiver (REC) domain and an Myb DNA-binding (MYB) domain at the N-terminus. As transcription factors, all five type-B LlRRs localize at the nucleus and are widely expressed in plant tissues, especially during axillary meristem (AM) formation. Functional analysis showed that type-B LlRRs are involved in bulbil formation in a functionally redundant manner and can activate LlRR9 expression. In summary, our study elucidates the process by which cytokinins regulate bulbil initiation in L. lancifolium through type-B LlRRs and lays a foundation for research on the molecular mechanism of bulbil formation in the lily.

Remote Mesoscopic Signatures of Induced Magnetic Texture in Graphene

Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this Letter, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much larger than e^{2}/h. This violation of one of the fundamental tenets of mesoscopic physics dramatically demonstrates how local considerations can be overwhelmed by remote signatures in phase-coherent conductors.

LhGST is an anthocyanin-related glutathione S-transferase gene in Asiatic hybrid lilies (Lilium spp.)

LhGST, an anthocyanin-related GST gene, was identified from Asiatic hybrid lilies. Expression and functional analyses demonstrated that LhGST might be involved in anthocyanin sequestration in lily tepals. Anthocyanins are responsible for the pink, red and purple pigmentation of flowers in Asiatic hybrid lilies, synthesized at the cytoplasmic surface of the endoplasmic reticulum (ER) and then transported to the vacuole. To date, the mechanism involved in the intracellular transport of anthocyanins in lilies has not been well elucidated. Here, full-length glutathione S-transferase gene (LhGST) was identified from lilies. Expression analysis revealed that LhGST was positively correlated with anthocyanin accumulation. Phylogenetic tree analysis showed that LhGST clustered with other anthocyanin-related GSTs in the same phi clade. Moreover, functional complementation of an Arabidopsis tt19 mutant demonstrated that LhGST might be involved in anthocyanin accumulation in lily tepals. Additionally, according to phenotype analysis, LhGST was found to be correlated with the transport of anthocyanin in lilies by virus-induced gene silencing (VIGS) assay. In addition, cis-element analysis of the LhGST promoter showed the presence of ABA-, auxin-, MeJA-, gibberellin-, light-, and stress-responsive elements and an MYB recognition site (MRS, CCGTTG). Yeast one-hybrid and dual-luciferase report assays revealed that the promoter of LhGST was activated by LhMYB12-lat, which is a key R2R3-MYB transcription factor that regulates anthocyanin biosynthesis in lilies. In conclusion, our results revealed that LhGST plays a key role in anthocyanin transport and accumulation in the tepals of lilies.

Raman Study of Cooper Pairing Instabilities in (Li_{1-x}Fe_{x})OHFeSe

We studied the electronic Raman spectra of (Li_{1-x}Fe_{x})OHFeSe as a function of light polarization and temperature. In the B_{1g} spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below T_{c}. The nearly resolution-limited peak at 110  cm^{-1} (13.6 meV) is identified as a collective mode. The peak at 190  cm^{-1} (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li_{1-x}Fe_{x})OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A_{1g} and B_{2g} symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.

Mechanism of exogenous cytokinins inducing bulbil formation in Lilium lancifolium in vitro

The cytokinin pathway promotes the initiation of bulbil formation, and iPA may an important type of cytokinin during bulbil formation in Lilium lancifolium. Bulbils are important vegetative reproductive organs in triploid Lilium lancifolium. We previously showed that cytokinins are involved in bulbil formation, but how cytokinins participate in bulbil formation is not clear. In this study, bulbil formation was divided into three stages on the basis of anatomical and histological observations: the bulbil initiation stage, bulbil primordium-formation stage and bulbil structure-formation stage. The results indicated that iPA was the most critical cytokinin during the bulbil initiation. qRT-PCR revealed that increased iPA content during bulbil initiation was mainly due to increased expression of cytokinin synthesis genes (IPT1/5) and cytokinin activation genes (LOG1/3/5/7) and significantly decreased expression of the cytokinin degradation gene CKX4. Exogenous 6-BA and lovastatin affected the cytokinin pathway and promoted or inhibited bulbil initiation by increasing or decreasing the content of endogenous iPA, respectively. In summary, we demonstrate that cytokinins positively regulate bulbil formation and provide preliminary insight into the regulatory mechanisms by which the cytokinin pathway promotes bulbil initiation.

Universal scaling of weak localization in graphene due to bias-induced dispersion decoherence

The differential conductance of graphene is shown to exhibit a zero-bias anomaly at low temperatures, arising from a suppression of the quantum corrections due to weak localization and electron interactions. A simple rescaling of these data, free of any adjustable parameters, shows that this anomaly exhibits a universal, temperature- (T) independent form. According to this, the differential conductance is approximately constant at small voltages (V < kBT/e), while at larger voltages it increases logarithmically with the applied bias. For theoretical insight into the origins of this behaviour, which is inconsistent with electron heating, we formulate a model for weak-localization in the presence of nonequilibrium transport. According to this model, the applied voltage causes unavoidable dispersion decoherence, which arises as diffusing electron partial waves, with a spread of energies defined by the value of the applied voltage, gradually decohere with one another as they diffuse through the system. The decoherence yields a universal scaling of the conductance as a function of eV/kBT, with a logarithmic variation for eV/kBT > 1, variations in accordance with the results of experiment. Our theoretical description of nonequilibrium transport in the presence of this source of decoherence exhibits strong similarities with the results of experiment, including the aforementioned rescaling of the conductance and its logarithmic variation as a function of the applied voltage.

Effects of wet atmospheric nitrogen deposition on epiphytic lichens in the subtropical forests of Central China: Evaluation of the lichen food supply and quality of two endangered primates

Over the last few decades, the threat posed to biodiversity and ecosystem function by atmospheric nitrogen (N) deposition has been increasingly recognized. The disturbed nutrient balance and species composition of plants induced by higher N deposition can impact the biodiversity of the organisms that consume the plants. In this research, we implemented several experiments to estimate the effects of increased N deposition on the growth, survival, and nutrients of the dominant epiphytic lichens in the subtropical mountains in Central China to assess the lichen food amount and nutritional quality for two endangered primates endemic to China. Our results indicated that the thallus growth and propagule survival of the lichens were significantly decreased when nitrogen addition changed from 6.25 to 50.0 kg N·ha^-1·y^-1; it was also shown that lichen biomass could be decreased by 11.2%-70.2% when the deposition addition exceeded 6.25 kg N·ha^-1·y^-1. Further, our study revealed that increased nitrogen deposition also reduced the nutritional quality of the lichens via reducing the soluble protein and soluble sugar levels and increasing the fiber content, which would substantially affect the diet selection of the plants consumers in the region, particularly the populations of the two lichen-eating endangered primate species, Rhinopithecus roxellana and R. bieti. Our experimental study suggested that the nitrogen pollution derived from anthropogenic activities could cause cascading effects for the whole forest ecosystem of Central China; thus, more studies about nitrogen deposition in this region are required.

Isolation of H8N4 avian influenza virus from wild birds in Shanghai, China

The H8 subtype viruses are rarely isolated from wild ducks. Shanghai is one of the important wintering or stopover sites on the East Asia-Australia Migration Flyway. An influenza virus, subtype H8N4, was firstly isolated from a common teal (Anas crecca) in Shanghai during 2017-2018 in this study. To clarify the genetic characteristics of the H8N4 virus, the whole genome sequences were analyzed. Phylogenetic analysis of the hemagglutinin and neuraminidase genes showed that they shared highest nucleotide identity (99.19%-99.64%) with the Japan duck-origin H8N4 virus collected in 2016 (A/duck/Aichi/231003/2016) and belonged to the Eurasian-like avian lineage. Six other genes of the H8N4 isolated virus were all highly similar to the corresponding genes of a wide range of AIV subtypes including H9N2, H5N7, H3N8, H1N2, H4N6 and H1N1. The results indicated that the H8N4 virus was a multiple reassortant virus. The study emphasized that the continuous surveillance of influenza virus in wild birds should be strengthened. Keywords: avian influenza virus; H8N4; phylogenetic analysis; Shanghai.

Semi-dominant mutation in the cysteine-rich receptor-like kinase gene, ALS1, conducts constitutive defence response in rice

Plants have evolved a sophisticated two-branch defence system to prevent the growth and spread of pathogen infection. The novel Cys-rich repeat (CRR) containing receptor-like kinases, known as CRKs, were reported to mediate defence resistance in plants. For rice, there are only two reports of CRKs. A semi-dominant lesion mimic mutant als1 (apoptosis leaf and sheath 1) in rice was identified to demonstrate spontaneous lesions on the leaf blade and sheath. A map-based cloning strategy was used for fine mapping and cloning of ALS1, which was confirmed to be a typical CRK in rice. Functional studies of ALS1 were conducted, including phylogenetic analysis, expression analysis, subcellular location and blast resistance identification. Most pathogenesis-related (PR) genes and other defence-related genes were activated and up-regulated to a high degree. ALS1 was expressed mainly in the leaf blade and sheath, in which further study revealed that ALS1 was present in the vascular bundles. ALS1 was located in the cell membrane of rice protoplasts, and its mutation did not change its subcellular location. Jasmonic acid (JA) and salicylic acid (SA) accumulation were observed in als1, and enhanced blast resistance was also observed. The mutation of ALS1 caused a constitutively activated defence response in als1. The results of our study imply that ALS1 participates in a defence response resembling the common SA-, JA- and NH1-mediated defence responses in rice.

Etching gas-sieving nanopores in single-layer graphene with an angstrom precision for high-performance gas mixture separation

One of the bottlenecks in realizing the potential of atom-thick graphene membrane for gas sieving is the difficulty in incorporating nanopores in an otherwise impermeable graphene lattice, with an angstrom precision at a high-enough pore density. We realize this design by developing a synergistic, partially decoupled defect nucleation and pore expansion strategy using O₂ plasma and O₃ treatment. A high density (ca. 2.1 × 10¹² cm^-2) of H₂-sieving pores was achieved while limiting the percentage of CH₄-permeating pores to 13 to 22 parts per million. As a result, a record-high gas mixture separation performance was achieved (H₂ permeance, 1340 to 6045 gas permeation units; H₂/CH₄ separation factor, 15.6 to 25.1; H₂/C₃H₈ separation factor, 38.0 to 57.8). This highly scalable pore etching strategy will accelerate the development of single-layer graphene-based energy-efficient membranes.

[The treatment of nose-eye correlated diseases with external nasal incision combined with nasal cavity approach surgery through endoscope]

Objective:To explore the indications and characteristics for the treatment of nose-eye correlated diseases with endoscopic surgery through external nasal incision combined with nasal cavity approach.Method:The clinical data of 13 patients whom hospitalized in our department and treated by endoscopic surgery through external nasal incision combined with nasal cavity approach since October 2011, were retrospectively analyzed and the characteristics of different pathological changes, clinical manifestations, surgical approach and follow-up results were summarized.Four cases of patients underwent endoscopic surgery through nasal cavity and lacrimal caruncle conjunctival incision, 4 cases received bone fracture reduction and DCR with endoscope through double path of nasal cavity and the original trauma wound, 2 cases with endoscopic bone tumor resection through nasal cavity and external nasal incision, the rest of the 3 cases with endonasal endoscopic and peri-orbit incision surgery.Result:Two cases of tumor patients showed no recurrence followed up for 1.5 to 2 years; the diplopia disappeared in 2 cases of orbital medial wall fracture; surgeries of 4 cases of orbital wall fracture with lacrimal duct obstruction patients, 3 cases succeeded, 1 case failed and change into dacryocystorhinotomy with external nasal incision, and epiphora of all patients vanished; all of the patients of sinus osteoma, foreign bodies and abscess were cured and symptoms disappeared; the symptoms of ectopic meningioma patient gradually died down with eyebrow scars left.Conclusion:The surgery with external nasal incision combined with nasal cavity approach through endoscope to treat noseeye correlated diseases can effectively deal with relevant pathological changes, with the advantages of clear operation field and less damage, but its exact indications and surgical methods still need to be further explored.

Tobacco rattle virus-induced PHYTOENE DESATURASE (PDS) and Mg-chelatase H subunit (ChlH) gene silencing in Solanum pseudocapsicum L

Virus-induced gene silencing (VIGS) is an attractive tool for determining gene function in plants. The present study constitutes the first application of VIGS in S. pseudocapsicum, which has great ornamental and pharmaceutical value, using tobacco rattle virus (TRV) vectors. Two marker genes, PHYTOENE DESATURASE (PDS) and Mg-chelatase H subunit (ChlH), were used to test the VIGS system in S. pseudocapsicum. The photobleaching and yellow-leaf phenotypes of the silenced plants were shown to significantly correlate with the down-regulation of endogenous SpPDS and SpChlH, respectively (P ≤ 0.05). Moreover, the parameters potentially affecting the efficiency of VIGS in S. pseudocapsicum, including the Agrobacterium strain and the inoculation method (leaf syringe-infiltration, sprout vacuum-infiltration and seed vacuum-infiltration), were compared. The optimized VIGS parameters were the leaf syringe-infiltration method, the Agrobacterium strain GV3101 and the growth of agro-inoculated plants at 25°. With these parameters, the silencing efficiency of SpPDS and SpChlH could reach approximately 50% in S. pseudocapsicum. Additionally, the suitability of various reference genes was screened by RT-qPCR using three candidate genes, and the results demonstrated that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) can serve as a suitable reference for assessing the gene expression levels of VIGS systems in S. pseudocapsicum. The proven application of VIGS in S. pseudocapsicum and the characterization of a suitable reference gene in the present work will expedite the functional characterization of novel genes in S. pseudocapsicum.

Total synthesis of teixobactin and its stereoisomers

The total syntheses of teixobactin and a series of its stereoisomers at positions 2, 5, 6, 10 and 11 were achieved via a combined strategy of solution and solid phase peptide synthesis.

High throughput in vitro and in vivo screening of inland waters of Southern California

The impact of unmonitored contaminants, also known as contaminants of emerging concern (CECs), on freshwater streams remains largely uncharacterized. Water samples from 31 streams representing urban, agricultural and undeveloped (i.e., open space) land use in Southern California (USA) were analyzed for in vitro and in vivo bioactivity. The extent and magnitude of bioactivity screened using endocrine-responsive cell bioassays and a fish embryo screening assay were low. In contrast, a wider gradient of responses for the aryl hydrocarbon receptor (AhR) assay was observed, which was negatively correlated with a measure of benthic community structure. Both aromatic and non-aromatic CECs were tentatively identified in these samples, but polycyclic aromatic hydrocarbons (PAHs), known AhR agonists in urban environments, were not present at detectable levels. These results suggest that a combination of in vitro and in vivo show potential as screening techniques for biological condition in situ, but that more advanced, comprehensive analytical methods are needed to identify bioactive contaminants.

[The study of locating facial nerve precisely in middle ear surgery based on clinical anatomy]

Objective:To investigate the methods of locating facial nerve precisely in middle ear surgery through the observation and measurement of the facial nerve and surrounding anatomical structures and to provide reference for the middle ear surgery.Method:Combined surgical approach on 15 cases (30 sides) fresh adult cadaveric specimens were dissected, observed the characteristics of facial nerve and its shape and spatial relationship of the surrounding structures, and measured the distance between the facial nerve and its surrounding structures.Result:The shortest distance from the midpoint of the posterior wall of external auditory canal (annulus level) to the vertical segment of the facial nerve was (3.37±0.34)mm, the shortest distance from the leading edge of the sigmoid sinus to the vertical segment of facial nerve was (7.40±0.71)mm, the shortest distance from the lateral margin of jugular bulb to the facial nerve was (5.58±0.79)mm, the shortest distance from Henle crest to the pyramidal segment of facial nerve was (12.76±1.24)mm, the shortest distance between the pyramidal segment of facial nerve and the posterior short limb of incus was (1.56±0.35)mm, the shortest distance between the pyramidal segment of facial nerve and the lower edge of posterior semicircular canal was (2.56±0.41) mm, the shortest distance between the lower edge of horizontal semicircular canal and the horizontal segment of facial nerve was (1.28±0.32) mm, the shortest distance between the upper edge of vestibular window and the horizontal segment of facial nerve was (0.67±0.15)mm.Conclusion:A good command of the anatomy of temporal bone as well as the methods of locating facial nerve will provide the key to reduce the probability of iatrogenic facial nerve injury in middle ear surgery.

Contrast-enhanced ultrasound in the diagnosis of orbital space-occupying lesions

AIM

To summarise the sonographic findings and assess the feasibility of contrast-enhanced ultrasound (CEUS) as an imaging method for the diagnosis of orbital space-occupying lesions.

MATERIALS AND METHODS

This was a prospective study of 53 patients who underwent orbital ultrasound at Xijing Hospital. Two-dimensional ultrasound, colour Doppler flow imaging (CDFI), and CEUS imaging were obtained and compared in patients with orbital haemangioma, pseudotumour, melanoma of the choroid, and retinoblastoma.

RESULTS

CEUS imaging cannot only visualise the location, shape, border, acoustic properties of a lesion, and interactions between the lesion and surrounding tissues, but also display the microvasculature and tissue perfusion within the lesion. The information obtained from CEUS imaging is valuable for diagnosis and differential diagnosis of orbital space-occupying lesions.

CONCLUSION

CEUS imaging allowed better visualisation of the lesions, enabled detection of vascular changes, increased the signal-to-noise ratio, and increased the sensitivity of detection of changes in perfusion in the microcirculation. It has relatively high sensitivity and specificity in the diagnosis of orbital space-occupying lesions and increases the accuracy of diagnosis.

Tumour-activated liver stromal cells regulate myeloid-derived suppressor cells accumulation in the liver

Regulating mechanisms underlying hepatic myeloid-derived suppressor cell (MDSC) accumulation remain to be described. Here, we provide evidence for the involvement of tumour-activated liver stromal cells in the process of hepatic MDSCs migration and accumulation. Our data showed an elevated frequency of MDSCs in the liver of tumour-bearing mice. Moreover, tumour-activated liver stromal cells promote MDSC migration into the liver site. Further investigation indicated higher levels of cytokine and chemokine expression in liver stromal cells after exposure to the tumour-conditioned supernatant. Notably, the expression levels of proinflammatory factors, mainly including macrophage colony stimulating factor (M-CSF), transforming growth factor-β (TGF-β), monocyte chemotactic protein-1 (MCP-1) and stromal-derived factor-1 (SDF-1), increased after treatment with tumour-conditioned supernatant, and blockade of MCP-1 or SDF-1 decreased the proportion of tumour infiltrated MDSCs in mice co-transplanted with liver stromal cells and tumour cells, but not in mice with only tumour cells injection. These findings demonstrate that tumour-activated liver stromal cells produce higher levels of chemokines and cytokines, which may contribute to MDSC accumulation into the liver site in patients with liver cancer.

Simultaneous detection of 45 fusion genes in leukemia by dual-color fluorescence real-time PCR

INTRODUCTION

Detection of recurrent genetic abnormalities is of great significance for a refined diagnosis and assessment of prognosis in leukemia. Conventional nested reverse transcription PCR is labor intensive and time-consuming.

METHODS

We have developed a novel dual-color TaqMan probe-based real-time PCR method for the simultaneous screening of 45 fusion transcripts in 12 parallel reactions. The method was tested and validated with cell lines carrying known fusion transcripts and patient samples.

RESULTS

A multiplex real-time PCR method was successfully developed for rapid detection of 45 fusion genes and validated for 15 of the more commonly detected fusion genes. Intra-assay reproducibility assessed for the most frequent rearrangements ranged from 0.41% to 0.74% for the coefficient of variation (CV) of cycle threshold (Ct) and the interassay reproducibility ranged from 1.62% to 2.83% in five separate experiments. The lowest detection limit for the translocations tested ranged between 1 : 16 000 and 1 : 32 000. Validation of the method with 213 patient samples showed 100% specificity and excellent consistence with conventional nested RT-PCR.

CONCLUSION

Overall, we believe that this method is easily applicable, cost-effective, and clinically useful for a rapid screening of fusion genes in the initial diagnostic phase of leukemia. Its use can also be extended to the monitoring of minimal residual disease.

Histological and Transcriptomic Analysis during Bulbil Formation in Lilium lancifolium

Aerial bulbils are an important propagative organ, playing an important role in population expansion. However, the detailed gene regulatory patterns and molecular mechanism underlying bulbil formation remain unclear. Triploid Lilium lancifolium, which develops many aerial bulbils on the leaf axils of middle-upper stem, is a useful species for investigating bulbil formation. To investigate the mechanism of bulbil formation in triploid L. lancifolium, we performed histological and transcriptomic analyses using samples of leaf axils located in the upper and lower stem of triploid L. lancifolium during bulbil formation. Histological results indicated that the bulbils of triploid L. lancifolium are derived from axillary meristems that initiate de novo from cells on the adaxial side of the petiole base. Transcriptomic analysis generated ~650 million high-quality reads and 11,871 differentially expressed genes (DEGs). Functional analysis showed that the DEGs were significantly enriched in starch and sucrose metabolism and plant hormone signal transduction. Starch synthesis and accumulation likely promoted the initiation of upper bulbils in triploid L. lancifolium. Hormone-associated pathways exhibited distinct patterns of change in each sample. Auxin likely promoted the initiation of bulbils and then inhibited further bulbil formation. High biosynthesis and low degradation of cytokinin might have led to bulbil formation in the upper leaf axil. The present study achieved a global transcriptomic analysis focused on gene expression changes and pathways' enrichment during upper bulbil formation in triploid L. lancifolium, laying a solid foundation for future molecular studies on bulbil formation.

[Endonasal endoscopic surgery in treatment of medial recus muscle entrapment: the management and effectiveness]

Objective:To explore the indications , surgery method and effect for the treatment of medial rectus muscle entrapment with endoscopic surgery.Method: Eight medial rectus muscle entrapment patients were enrolled in this study,3 cases underwent obital medial wall fracture reposition and medial rectus muscle adhesion decomposition surgery through endonasal endoscope,and 5 cases received obital medial wall fracture reposition surgery with endoscope through nasal cavity and lacrimal caruncle conjunctival incision. Result:The diplopia disappeared and eyeball abduction function recovered in 6 cases of medial rectus muscle entrapment patients within 2 months,and 1 case with each surgery had mild diplopia and eyeball incomplete abduction left.Conclusion:Adopting endonasal endoscopic surgery or dual approaches surgery with endonasal endoscopic and transcaruncular surgery were ideal methods for medial rectus muscle entrapment diseases.Surgery with endoscope has the characteristics of clear field and less damage.The surgery should be performed whithin 3 weeks, and the entrapment of medial rectus muscle can be resoved effectively.

Thermally Assisted Nonvolatile Memory in Monolayer MoS2 Transistors

We demonstrate a novel form of thermally-assisted hysteresis in the transfer curves of monolayer MoS₂ FETs, characterized by the appearance of a large gate-voltage window and distinct current levels that differ by a factor of ∼10². The hysteresis emerges for temperatures in excess of 400 K and, from studies in which the gate-voltage sweep parameters are varied, appears to be related to charge injection into the SiO₂ gate dielectric. The thermally-assisted memory is strongly suppressed in equivalent measurements performed on bilayer transistors, suggesting that weak screening in the monolayer system plays a vital role in generating its strongly sensitive response to the charge-injection process. By exploiting the full features of the hysteretic transfer curves, programmable memory operation is demonstrated. The essential principles demonstrated here point the way to a new class of thermally assisted memories based on atomically thin two-dimensional semiconductors.

[Outcomes of total deafness type of idiopathic suddendeafness in different ages]

Objective:This retrospective study was aimed to investigate the characteristics of hearing recovery in the complete deafness type of SSNHL(≥81 dBHL) in patients with different ages.Method:Clinical outcomes of 179 total deafness type of idiopathic sudden deafness were compared.Patients were divided into 5 groups according to age,they were,pediatric group(13 years or less),youthful group(14-44 years),middle-aged group(45-59 years),presenium group(60-74 years),senectitude group(75 years or higher).Patients were divided into 3 groups according to the initial degree of hearing loss: 81 dB group (81-89 dBHL),90 dB group(90- 99 dBHL),100 dB group(100 dBHL or higher).Routine comprehensive treatment including corticosteroids,the inner ear microcirculation improvement drugs,neurotrophic drugs,saturationoxygen and hyperbaric oxygen therapy,etc.was applied.Patients were treated in accordance with the age and body weight.Result:The percentage of youthful group(83/179,46.4%) was highest(P<0.05),middle-aged group(57/179,31.8%)followed(P<0.05),presenium group(26/179,14.5%)was lower(P<0.05),pediatric group(8/179,4.5%) and senectitude group(5/179,2.8%)were the lowest.No a complete recovery in either pediatric group or senectitude group.A complete recovery was rare in the other groups.Recovery rate of the different aged groups was similar(P>0.05).The percentage of 100 dB group(108/179,60.3%) was highest(P<0.05).The percentage of 81 dB group(39/179,21.8%)was similar to 90 dB group(32/179,17.9%)(P>0.05).Recovery rate was similar in 81 dB group(25/39,64.1%)and 90 dB group(18/32,56.2%)(P>0.05).Recovery rate of both 81 dB group and 90 dB group were greater than 100 dB group(24/108,22.2%)(P<0.05).The 100 dB group reduced the satisfactory recovery effects.There were no differences in the proportion of the patients with dizziness(95/179,53.1%)and without dizziness(84/179,46.9%)(P>0.05).Recovery rate of patients without dizziness(43/84,51.2%) was greater than with dizziness(24/95,25.3%)(P<0.05).The percentage of the patients without dizziness(31/39,79.5%)in 81 dB group was the highest(P<0.05),90 dB group(18/32,56.2%)followed(P<0.05).The percentage of the patients with dizziness in 100 dB group(73/108,67.6%)was highest(P<0.05).Recovery rate was similar in the patients without dizziness of 81 dB group(21/31,67.7%)and 90 dB group(11/18,61.1%)(P>0.05).Recovery rate of the above two groups was greater than that of 100 dB group(11/35,31.4%)(P<0.05).Conclusion:Recovery rate of the different aged groups was similar.The percentage of the patients with dizziness in 100 dB group was highest.Initial hearing threshold in excess of 100 dB reduced the satisfactory recovery in patients with total deafness type of SSNHL.Our results provided a good reference for other clinicians.

Tristetraprolin: a novel mediator of the anticancer properties of resveratrol

Resveratrol is a natural compound that exhibits anticancer properties. Previous studies have proved that it can inhibit the proliferation of breast cancer cell lines and upregulate some cytokines such as cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). The initiation and progression of cancer are associated with the abnormal expression of multiple cytokines. Tristetraprolin (TTP), an mRNA-binding protein, is one of the key proteins that participate in regulating cytokine expression. Two different proliferation assays on MCF-7 cells showed that the cell proliferation rate significantly reduced following treatment with resveratrol. Most importantly, we found that resveratrol promoted TTP expression at both the mRNA and protein level in a dose- and time-dependent manner. In addition, the expression of COX-2 and VEGF were significantly suppressed by resveratrol while that of inducible nitric oxide synthase (iNOS) was upregulated. Lastly, the effects of resveratrol on both MCF-7 proliferation and expression of COX-2, VEGF, and iNOS were significantly inhibited by TTP knockdown, indicating that TTP mediates the anticancer properties of resveratrol. In summary, we conclude that resveratrol inhibits the proliferation of MCF-7 cells by TTP upregulation, which is associated with downregulation of COX-2 and VEGF and upregulation of iNOS.

"Freeing" Graphene from Its Substrate: Observing Intrinsic Velocity Saturation with Rapid Electrical Pulsing

Rapid (nanosecond-scale) electrical pulsing is used to study drift-velocity saturation in graphene field-effect devices. In these experiments, high-field pulses are utilized to drive graphene's carriers on time scales much faster than that on which energy loss to the underlying substrate can occur, thereby allowing the observation of the highest saturation velocities reported to date. In a dramatic departure from the behavior exhibited by conventional metals and semiconductors, as the electron or hole density is reduced toward the charge-neutrality point, the drift velocity is found to reach values comparable to the Fermi velocity itself. Corresponding current densities are as large as 10(9) A/cm(2), similar to the values reported for carbon nanotubes and for graphene-on-diamond transistors. In essence, our approach of rapid pulsing allows us to "free" graphene from the deleterious influence of its substrate, revealing a pathway to achieve the superior electrical performance promised by this material. The usefulness of this approach is not merely limited to graphene but should extend also to a broad variety of two-dimensional semiconductors.

Block copolymer synthesis by controlled/living radical polymerisation in heterogeneous systems

We review the range of CLRP-controlled syntheses of block copolymer particles in dispersed systems, which are being exploited to create new opportunities for the design of nanostructured soft materials.

Palladium-catalyzed arylation of β-methylene C(sp3)–H bonds at room temperature: desymmetrization of simple cycloalkyl carboxylic acids

A new protocol for Pd-catalyzed β methylene C–H arylation of N-quinolyl cycloalkylcarboxamides with aryl iodides at room temperature is reported.