Prevalence and Importance of the Necrotrophic Effector Gene ToxA in Bipolaris sorokiniana Populations Collected from Spring Wheat and Barley.

Bipolaris sorokiniana is a necrotrophic fungal pathogen that causes foliar and root diseases on wheat and barley. These diseases are common in all wheat- and barley-growing regions, with more severe outbreaks occurring under warm and humid conditions. B. sorokiniana can also infect a wide range of grass species in the family Poaceae and secrete ToxA, an important necrotrophic effector also identified other wheat leaf spotting pathogens. In this study, the prevalence and virulence role of ToxA were investigated in a collection of 278 B. sorokiniana isolates collected from spring wheat and barley in the Upper Midwest of the United States or other places, including 169 from wheat leaves, 75 from wheat roots, 30 from barley leaves, and 4 from wild quack grass leaves. ToxA was present in the isolates from wheat leaves, wheat roots, and wild grass leaves but was absent from isolates collected from barley leaves. Prevalence of ToxA in wheat leaf isolates (34.3%) was much higher than that in wheat root isolates (16%). Sequencing analysis revealed the presence of two haplotypes, with the majority being BsH2. All ToxA+ isolates produced the functional effector in liquid cultures. Pathogenicity assays revealed that ToxA+ isolates caused significantly more disease on spring wheat lines harboring Tsn1 than their tsn1 mutants, suggesting that the ToxA-Tsn1 interaction plays an important role in spot blotch development. This work confirms the importance of ToxA in B. sorokiniana populations infecting wheat and, thus, the need to eliminate Tsn1 from spring wheat cultivars to reduce susceptibility to spot blotch.

Cryptococcal Meningitis in a Patient with Sjogren's Syndrome: a Case Report.

BACKGROUND: Cryptococcal meningitis (CM) is a life-threatening infectious disease and causes high morbidity and mortality. No information about Cryptococcal meningitis in populations with Sjogren's syndrome (SS) was available. METHODS: This report details the first case of Cryptococcal meningitis in a 75-year-old female patient with 10-years history of Sjogren's syndrome. RESULTS: Detailed findings of C. neoformans from CSF examinations, including routine examination, India ink stain, immunological test, culturing, mass spectrum analysis and molecular biology identification were all delineated in this case, which facilitated understanding of detection methods in C. neoformans infection. The etiological exploration was initiated from a positive finding of yeast cells in routine examination of unstained CSF in the present case. Morphology description of C. neoformans in unstained CSF was depicted for the first time. CONCLUSIONS: Clinicians should consider the possible complication of Cryptococcal meningitis when patients with Sjogren's syndrome show neurological symptoms. Importance of screening yeast cells from unstained CSF for routine examination was emphasized, which may reduce errors in cell counting and trigger further etiological ex-ploration of C. neoformans infection in laboratory and clinical practice.

Systematic Analysis Identifies a Specific RNA-Binding Protein-Related Gene Model for Prognostication and Risk-Adjustment in HBV-Related Hepatocellular Carcinoma.

OBJECTIVE: Increasing evidence shows that dysregulated RNA binding proteins (RBPs) modulate the progression of several malignancies. Nevertheless, their clinical implications of RBPs in HBV-related hepatocellular carcinoma (HCC) remain largely undefined. Here, this study systematically analyzed the associations of RBPs with HBV-related HCC prognosis. METHODS: Based on differentially expressed RBPs between HBV-related HCC and control specimens, prognosis-related RBPs were screened by univariate analyses. A LASSO model was then created. Kaplan-Meier curves, ROCs, multivariate analyses, subgroup analyses and external verification were separately applied to assess the efficacy of this model in predicting prognosis and recurrence of patients. A nomogram was created by incorporating the model and clinical indicators, which was verified by ROCs, calibration curves and decision curve analyses. By CIBERSORT algorithm, the association between the risk score and immune cell infiltrations was evaluated. RESULTS: Totally, 54 RBPs were distinctly correlated to prognosis of HBV-related HCC. An 11-RBP model was created, containing POLR2L, MRPS12, DYNLL1, ZFP36, PPIH, RARS, SRP14, DDX41, EIF2B4, and NOL12. This risk score sensitively and accurately predicted one-, three- and five-year overall survival, disease-free survival, and progression-free interval. Compared to other clinical parameters, this risk score had the best predictive efficacy. Also, the clinical generalizability of the model was externally verified in the GSE14520 dataset. The nomogram may predict patients' survival probabilities. Also, the risk score was related to the components in the immune microenvironment. CONCLUSION: Collectively, RBPs may act as critical elements in the malignant progression of HBV-related HCC and possess potential implications on prognostication and therapy decision.

Clinical implications of serum hepatitis B virus RNA quantitation in untreated chronic hepatitis B virus-infected patients.

Serum hepatitis B virus (HBV) RNA quantitation may be useful for managing untreated chronic HBV-infected patients, but its distribution characteristics and relationship to HBV DNA are unclear. A retrospective cohort including 149 untreated HBV-infected patients was divided into four clinical phenotypes: hepatitis B envelope antigen (HBeAg) positive with normal alanine transaminase (ALT; EPNA) or with elevated ALT (EPEA), HBeAg-negative with normal ALT (ENNA) or with elevated ALT (ENEA). Serum HBV RNA levels were quantified by a high-sensitivity real-time fluorescent quantitative PCR method and liver biopsy was performed in those with undetectable serum HBV DNA or RNA. The detectable serum HBV RNA levels (log10 copies/mL) in EPNA, EPEA, ENNA, and ENEA were 6.02±1.48, 6.54±1.27, 2.51±0.78 and 3.54±1.25, respectively. The low level (< 2.0 log10 copies/mL) comprised mainly of ENNA phenotype (76.9%), while the high level (> 6.0 log10 copies/mL) was HBeAg-positive patients (98.1%). Serum HBV RNA level were significantly correlated with serum HBV DNA and HBsAg in HBeAg-positive phenotypes, but a correlation only with HBV DNA was observed in ENEA patients. Serum HBV DNA and RNA were both independent risk factors associated with elevated ALT in HBeAg-negative patients. Seven serum HBV DNA-undetectable but RNA-detectable patients underwent liver biopsy, showing moderate or severe liver inflammation. Varying serum HBV RNA levels can reflect natural disease phases in untreated HBV-infected patients, indicating that this biomarker could reflect liver inflammation in untreated HBeAg-negative patients as successfully as serum HBV DNA. Serum HBV RNA can complement clinical management strategies when serum HBV DNA is undetectable.

De novo sequencing and comparative transcriptome analysis of the male and hermaphroditic flowers provide insights into the regulation of flower formation in andromonoecious taihangia rupestris.

BACKGROUND: Taihangia rupestris, an andromonoecious plant species, bears both male and hermaphroditic flowers within the same individual. However, the establishment and development of male and hermaphroditic flowers in andromonoecious Taihangia remain poorly understood, due to the limited genetic and sequence information. To investigate the potential molecular mechanism in the regulation of Taihangia flower formation, we used de novo RNA sequencing to compare the transcriptome profiles of male and hermaphroditic flowers at early and late developmental stages. RESULTS: Four cDNA libraries, including male floral bud, hermaphroditic floral bud, male flower, and hermaphroditic flower, were constructed and sequenced by using the Illumina RNA-Seq method. Totally, 84,596,426 qualified Illumina reads were obtained and then assembled into 59,064 unigenes, of which 24,753 unigenes were annotated in the NCBI non-redundant protein database. In addition, 12,214, 7,153, and 8,115 unigenes were assigned into 53 Gene Ontology (GO) functional groups, 25 Clusters of Orthologous Group (COG) categories, and 126 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. By pairwise comparison of unigene abundance between the samples, we identified 1,668 differential expressed genes (DEGs), including 176 transcription factors (TFs) between the male and hermaphroditic flowers. At the early developmental stage, we found 263 up-regulated genes and 436 down-regulated genes expressed in hermaphroditic floral buds, while 844 up-regulated genes and 314 down-regulated genes were detected in hermaphroditic flowers at the late developmental stage. GO and KEGG enrichment analyses showed that a large number of DEGs were associated with a wide range of functions, including cell cycle, epigenetic processes, flower development, and biosynthesis of unsaturated fatty acid pathway. Finally, real-time quantitative PCR was conducted to validate the DEGs identified in the present study. CONCLUSION: In this study, transcriptome data of this rare andromonoecious Taihangia were reported for the first time. Comparative transcriptome analysis revealed the significant differences in gene expression profiles between male and hermaphroditic flowers at early and late developmental stages. The transcriptome data of Taihangia would be helpful to improve the understanding of the underlying molecular mechanisms in regulation of flower formation and unisexual flower establishment in andromonoecious plants.

Simple and cost-effective methods for precise analysis of trace element abundances in geological materials with ICP-MS.

Inductively coupled plasma mass spectrometry (ICP-MS) is the most commonly used technique to determine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results. For this reason, we have done many experiments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190°C for only 2h for 50mg sample. In the case of isobaric interferences, although oxide (e.g., MO+/M+) and hydroxide (e.g., MOH+/M+) productivity is variable between runs, the (MO+/M+)/(CeO+/Ce+) and (MOH+/M+)/(CeO+/Ce+) ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control (QC) solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with recommended values of international rock reference standards with a relative error of <8% and precision generally better than 5%. Importantly, compared to the widely used analytical practice, we can effectively save >60% of time (e.g., <24h vs. >60h).

Activity Enhancement of G-Quadruplex/Hemin DNAzyme by Flanking d(CCC).

G-quadruplex (G4)/hemin DNAzymes have been extensively applied in bioanalysis and molecular devices. However, their catalytic activity is still much lower than that of proteinous enzymes. The G4/hemin DNAzyme activity is correlated with the G4 conformations and the solution conditions. However, little is known about the effect of the flanking sequences on the activity, though they are important parts of G4s. Here, we report sequences containing d(CCC), flanked on both ends of the G4-core sequences remarkably enhance their DNAzyme activity. By using circular dichroism and UV-visible spectroscopy, the d(CCC) flanking sequences were demonstrated to improve the hemin binding affinity to G4s instead of increasing the parallel G4 formation, which might explain the enhanced DNAzyme activity. Meanwhile, the increased hemin binding ability promoted the degradation of hemin within the DNAzyme by H2O2. Furthermore, the DNAzyme with d(CCC) flanking sequences showed strong tolerance to pH value changes, which makes it more suitable for applications requiring wide pH conditions. The results highlight the influence of the flanking sequences on the DNAzyme activity and provide insightful information for the design of highly active DNAzymes.

Upregulation of uncoupling protein Ucp2 through acute cold exposure increases post-thaw sperm quality in zebrafish.

Oxidative stress plays an important role in sperm damage during cryopreservation. Mild mitochondrial uncoupling has been shown to reduce excessive reactive oxygen species (ROS) and thus mitigate oxidative stress. Uncoupling protein (Ucp2) regulates mitochondrial uncoupling and can be induced by temperature fluctuation. In the present study, we explored a novel approach of acute cold exposure on Ucp2 activation and its association with oxidative damage and post-thaw sperm quality in zebrafish. Our study revealed that acute cold exposure of zebrafish at 18 °C for 24 h led to significant increase of ucp2 mRNA and Ucp2 protein in zebrafish fresh sperm as well as thawed sperm after cryopreservation. Although cold exposure had no effect on fresh sperm quality except for decreasing lipid peroxidation, sperm collected from cold-exposed zebrafish exhibited higher resistance to cryodamage, which was demonstrated by increased post-thaw motility, decreased lipid peroxidation, increased ATP production, and ultimately increased fertilization success. However, except for reduced lipid peroxidation, we did not observe any significant ROS reduction associated with increased Ucp2 activation in cold-exposed group, suggesting mechanisms other than mitochondrial uncoupling could have contributed to cold exposure associated benefits in post-thaw sperm survival. Nevertheless, our findings indicate that acute cold exposure prior to sperm cryopreservation is beneficial for post-thaw sperm survival in zebrafish, and this novel approach may be used to improve post-thaw sperm quality for other aquatic species.

Salt stress induces a decrease in excitation energy transfer from phycobilisomes to photosystem II but an increase to photosystem I in the cyanobacterium Spirulina platensis.

The effects of salt stress (0-0.8M NaCl) on excitation energy transfer from phycobilisomes to photosystem I (PSI) and photosystem II (PSII) in the cyanobacterium Spirulina platensis were investigated. Salt stress resulted in a significant decrease in photosynthetic oxygen evolution activity and PSII electron transport activity, but a significant increase in PSI electron transport activity. Analyses of the polyphasic fluorescence transients (OJIP) showed that, with an increase in salt concentration, the fluorescence yield at the phases J, I and P declined considerably and the transient almost leveled off at 0.8M NaCl. Analyses of the JIP test demonstrated that salt stress led to a decrease in the maximal efficiency of PSII photochemistry, the probability of electron transfer beyond Q(A), and the yield of electron transport beyond Q(A). In addition, salt stress resulted in a decrease in the electron transport per PSII reaction center, but an increase in the absorption per PSII reaction center. However, there was no significant change in the trapping per PSII reaction center. Furthermore, there was a decrease in the concentration of the active PSII reaction centers. Analyses of 77K chlorophyll fluorescence emission spectra excited either at 436 or 580nm showed that salt stress inhibited excitation energy transfer from phycobilisomes to PSII but induced an increase in the efficiency of energy transfer from phycobilisomes to PSI. Based on these results, it is suggested that, through a down-regulation of PSII reaction centers and a shift of excitation energy transfer in favor of PSI, the PSII apparatus was protected from excess excitation energy.

Characterization of photosystem II in salt-stressed cyanobacterial Spirulina platensis cells.

PSII activity was inhibited after Spirulina platensis cells were incubated with different salt concentrations (0-0.8 M NaCl) for 12 h. Flash-induced fluorescence kinetics showed that in the absence of DCMU, the half time of the fast and slow components decreased while that of the middle component increased considerably with increasing salt concentration. In the presence of DCMU, fluorescence relaxation was dominated by a 0.6s component in control cells. After salt stress, this was partially replaced by a faster new component with half time of 20-50 ms. Thermoluminescence measurements revealed that S(2)Q(A)(-) and S(2)Q(B)(-) recombinations were shifted to higher temperatures in parallel and the intensities of the thermoluminescence emissions were significantly reduced in salt-stressed cells. The period-four oscillation of the thermoluminescence B band was highly damped. There were no significant changes in contents of CP47, CP43, cytochrome c550, and D1 proteins. However, content of the PsbO protein in thylakoid fraction decreased but increased significantly in soluble fraction. The results suggest that salt stress leads to a modification of the Q(B) niche at the acceptor side and an increase in the stability of the S(2) state at the donor side, which is associated with a dissociation of the PsbO protein.

Controlled synthesis and upconverted avalanche luminescence of cerium(III) and neodymium(III) orthovanadate nanocrystals with high uniformity of size and shape.

We report on controlled synthesis of uniform LnVO4 (Ln = Ce and Nd) nanocrystals (NCs) with square-plate and H-shaped morphologies in nanosized reverse microemulsion reactors, via a facile solvo/hydrothermal strategy. The NCs were thoroughly characterized by X-ray diffraction, transmission electron microscopy (TEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), infrared absorption spectroscopy, and photoluminescence. Possible mechanisms of the rare-earth orthovanadate NC growth and size and shape evolution are proposed. A unique upconverted avalanche luminescence property pertaining to the NCs has been discovered, systematically studied, and mechanistically discussed. Our work combines synthetic and optical studies of the NCs and lays a foundation for reinventing their applications in optoelectronics among others.

The influence of surface trapping and dark states on the fluorescence emission efficiency and lifetime of CdSe and CdSe/ZnS quantum dots.

To investigate the influence of surface trapping and dark states on CdSe and CdSe/ZnS quantum dots (QDs), we studied the absorption, fluorescence intensity and lifetime by using one-and two-photon excitation, respectively. Experimental results show that both one- and two-photon fluorescence emission efficiencies of the QDs enhance greatly and the lifetime increase after capping CdSe with ZnS due to the effective surface passivation. The lifetime of one-photon fluorescence of CdSe and CdSe/ZnS QDs increase with increasing emission wavelength in a supralinear way, which is attributed to the energy transfer of dark excitons. On the contrary, the lifetime of two-photon fluorescence of bare and core-shell QDs decrease with increasing emission wavelength, and this indicates that the surface trapping is the dominant decay mechanism in this case.

Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region.

We demonstrate highly efficient avalanche multiphoton luminescence (MPL) from ordered-arrayed gold nanowires (NWs) with low time-average excitation intensity, Iexc (5.0-9.1 kW/cm2). The intensity of avalanche MPL, IMPL, is about 10(4) times larger than that of three-photon luminescence, the slope partial differential log IMPL/ partial differential log Iexc of avalanche MPL reaches as high as 18.3, and the corresponding polarization dependence of IMPL has a form of cos50 phip. The emission dynamics of avalanche MPL and three-photon luminescence are also studied comparatively. These observations indicate that the highly efficient avalanche MPL is attributed to the giant enhancement and coupling of longitudinal surface plasmon resonance of ordered-arrayed gold NWs.

Genetic engineering of the biosynthesis of glycinebetaine enhances thermotolerance of photosystem II in tobacco plants.

Genetically engineered tobacco (Nicotiana tabacum L.) with the ability to accumulate glycinebetaine was established. The wild type and transgenic plants were exposed to heat treatment (25-50 degrees C) for 4 h in the dark and under growth light intensity (300 mumol m(-2) s(-1)). The analyses of oxygen-evolving activity and chlorophyll fluorescence demonstrated that photosystem II (PSII) in transgenic plants showed higher thermotolerance than in wild type plants in particular when heat stress was performed in the light, suggesting that the accumulation of glycinebetaine leads to increased tolerance to heat-enhanced photoinhibition. This increased tolerance was associated with an improvement on thermostability of the oxygen-evolving complex and the reaction center of PSII. The enhanced tolerance was caused by acceleration of the repair of PSII from heat-enhanced photoinhibition. Under heat stress, there was a significant accumulation of H(2)O(2), O (2) (-) and catalytic Fe in wild type plants but this accumulation was much less in transgenic plants. Heat stress significantly decreased the activities of catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase in wild type plants whereas the activities of these enzymes either decreased much less or maintained or even increased in transgenic plants. In addition, heat stress increased the activity of superoxide dismutase in wild type plants but this increase was much greater in transgenic plants. Furthermore, transgenic plants also showed higher content of ascorbate and reduced glutathione than that of wild type plants under heat stress. The results suggest that the increased thermotolerance induced by accumulation of glycinebetaine in vivo was associated with the enhancement of the repair of PSII from heat-enhanced photo inhibition, which might be due to less accumulation of reactive oxygen species in transgenic plants.

Optical nonlinear absorption and refraction of CdS and CdS-Ag core-shell quantum dots.

The CdS and CdS-Ag core-shell quantum dots (QDs) have been prepared. The nanostructures of the QDs were revealed by transmisson electron microscopy and absorption spectra, respectively. The third-order nonlinear optical properties of the core-shell QDs have been studied by using Z-scan technique with femtosecond pulses at the wavelength of 790 nm. The value of the effective nonlinear absorption coefficient beta(eff) of CdS-Ag QDs is measured to be about 16.8 cm/GW, which is about 400 times larger than that of bare CdS QDs of 3.9 x 10(-2) cm/GW. The nonlinear refraction index gamma of CdS-Ag QDs is about -2.3 x 10(-4) cm(2)GW, which is about 200 times larger than that of bare CdS QDs of 1.0 x 10(-6) cm(2)GW.

Heat stress induces an inhibition of excitation energy transfer from phycobilisomes to photosystem II but not to photosystem I in a cyanobacterium Spirulina platensis.

The effects of high temperature (30-52.5 degrees C) on excitation energy transfer from phycobilisomes (PBS) to photosystem I (PSI) and photosystem II (PSII) in a cyanobacterium Spirulina platensis grown at 30 degrees C were studied by measuring 77 K chlorophyll (Chl) fluorescence emission spectra. Heat stress had a significant effect on 77 K Chl fluorescence emission spectra excited either at 436 or 580 nm. In order to reveal what parts of the photosynthetic apparatus were responsible for the changes in the related Chl fluorescence emission peaks, we fitted the emission spectra by Gaussian components according to the assignments of emission bands to different components of the photosynthetic apparatus. The 643 and 664 nm emissions originate from C-phycocyanin (CPC) and allophycocyanin (APC), respectively. The 685 and 695 nm emissions originate mainly from the core antenna complexes of PSII, CP43 and CP47, respectively. The 725 and 751 nm band is most effectively produced by PSI. There was no significant change in F725 and F751 during heat stress, suggesting that heat stress had no effects on excitation energy transfer from PBS to PSI. On the other hand, heat stress induced an increase in the ratio of Chl fluorescence yield of PBS to PSII, indicating that heat stress inhibits excitation energy transfer from PBS to PSII. However, this inhibition was not associated with an inhibition of excitation energy transfer from CPC to APC since no significant changes in F643 occurred at high temperatures. A dramatic enhancement of F664 occurring at 52.5 degrees C indicates that excitation energy transfer from APC to the PSII core complexes is suppressed at this temperature, possibly due to the structural changes within the PBS core but not to a detachment of PBS from PSII, resulting in an inhibition of excitation energy transfer from APC to PSII core complexes (CP47 + CP43). A decrease in F685 and F695 in heat-stressed cells with excitation at 436 nm seems to suggest that heat stress did not inhibit excitation energy transfer from the Chl a binding proteins CP47 and CP43 to the PSII reaction center and the decreased Chl fluorescence yields from CP43 and CP47 could be explained by the inhibition of the energy transfer from APC to PSII core complexes (CP47 + CP43).