Search

Mitogen-activated protein kinases (MAPKs) are important in regulating plant development as well as stress response. In this study, we genome-widely identified 56 MAPK genes in upland cotton. These MAPK genes unequally distribute on 22 chromosomes of cotton genome, but no MAPK gene is located on At_Chr6, Dt_Chr6, At_Chr13 and Dt_Chr13. The exons and introns in GhMAPK gene family vary widely at the position, number and length. Furthermore, GhMAPK family can be divided into 4 groups (A, B, C and D), and the TEY type of T-loop exists in three groups (A, B and C), but the TDY type of T-loop is only in group D. Further study revealed that some GhMAPK genes (including GhMPK6) are preferentially expressed in elongating fibers. GhMPK6 maintains a high phosphorylation level in elongating fibers, and its phosphorylation was enhanced in fibers by phytohormones brassinosteroid (BR), ethylene and indole-3-acetic acid (IAA). Additionally, GhMPK6 could interact with GhMKK2-2 and GhMKK4, suggesting that GhMKK2-2/4-GhMPK6 module may be involved in phosphorylation of its downstream proteins for regulating fiber elongation of cotton.

Controlling proliferation and aflatoxin production by Aspergillus flavus is a pressing challenge for global food safety and security. Marine bacterium Staphylococcus saprophyticus strain L-38 showed excellent antifungal activity toward A. flavus in vitro and in vivo. In sealed, non-contact confrontation assays, L-38 completely inhibited conidial germination and mycelial growth of A. flavus through the production of volatile organic compounds (VOCs). Gas chromatography-mass spectrometry identified 3,3-dimethyl-1,2-epoxybutane (3-DE) as the most abundant VOC (32.61% of total peak area, 78% matching). Exposure of A. flavus cultures to synthetic 3-DE similarly demonstrated strong inhibition of growth. Moreover, culture of L-38 in a sealed chamber with maize or peanuts artificially inoculated with A. flavus, at high water activity, resulted in significant inhibition of A. flavus germination and aflatoxin biosynthesis. Scanning electron microscopy of these samples revealed severe damage to conidial cells and hyphae compared to samples not exposed to L-38. L-38 also showed broad and effective antifungal activity toward eight other phytopathogenic fungi including Aspergillus niger, Fusarium verticillioides, Fusarium graminearum, Sclerotinia sclerotiorum, Rhizoctonia solani, Alternaria alternata, Monilinia fructicola, and Botrytis cinerea. This work introduces S. saprophyticus L-38 as a potential biocontrol agent and demonstrates the efficacy of the volatile 3-DE in the control of A. flavus and other destructive plant pathogens for post-harvest food safety.

Deoxynivalenol (DON) is one of the most widespread trichothecene mycotoxins in contaminated cereal products. DON plays a vital role in the pathogenesis of Fusarium graminearum, but the molecular mechanisms of DON underlying Fusarium–wheat interactions are not yet well understood. In this study, a novel wheat ADP-ribosylation factor-like protein 6-interacting protein 4 gene, TaArl6ip4, was identified from DON-treated wheat suspension cells by suppression subtractive hybridization (SSH). The qRT-PCR result suggested that TaArl6ip4 expression is specifically activated by DON in both the Fusarium intermediate susceptible wheat cultivar Zhengmai9023 and the Fusarium resistant cultivar Sumai3. The transient expression results of the TaARL6IP4::GFP fusion protein indicate that TaArl6ip4 encodes a plasma membrane and nucleus-localized protein. Multiple sequence alignment using microscale thermophoresis showed that TaARL6IP4 comprises a conserved DON binding motif, 67HXXXG71, and exhibits DON affinity with a dissociation constant (KD) of 91 ± 2.6 µM. Moreover, TaARL6IP4 exhibited antifungal activity with IC50 values of 22 ± 1.5 µM and 25 ± 2.6 µM against Fusarium graminearum and Alternaria alternata, respectively. Furthermore, TaArl6ip4 interacted with the plasma membrane of Fusarium graminearum spores, resulting in membrane disruption and the leakage of cytoplasmic materials. The heterologous over-expression of TaArl6ip4 conferred greater DON tolerance and Fusarium resistance in Arabidopsis. Finally, we describe a novel DON-induced wheat gene, TaArl6ip4, exhibiting antifungal function and DON affinity that may play a key role in Fusarium–wheat interactions.

The major causal agents Fusarium graminearum (F. graminearum) and Fusarium asiaticum could produce multiple mycotoxins in infected wheat, which threatens the health of humans and animals. Specifically, deoxynivalenol (DON) and its derivatives 3- and 15-acetyldeoxynivalenol (3-ADON and 15-ADON) are commonly detected mycotoxins in cereal grains. However, the good chromatographic separation of 3-ADON and 15-ADON remains challenging. Here, an LC-MS/MS method for the chemotype determination of Fusarium strains was developed and validated. 3- and 15-ADON could be separated chromatographically in this study with sufficiently low limits of detection (LODs, 4 μg/kg) and limits of quantification (LOQs, 8 μg/kg). The satisfying intraday and interday reproducibility (both %RSDr and %RSDR were &lt, 20%) of this method indicated good stability. The recoveries of all analytes were in the range of 80–120%. In addition, three F. graminearum complex (FGC) strains, i.e., PH-1 (chemotype 15-ADON), F-1 (chemotype 3-ADON) and 5035 (chemotype 15-ADON), were selected to verify the accuracy of the method in differentiating phenotypes. The validation results showed that this LC-MS/MS method based on sample pretreatment is effective and suitable for the chromatographic separation of 3-ADON and 15-ADON in wheat.

A previous report indicated that collagen hydrolysate fraction (F7) from Spanish mackerel (Scomberomorous niphonius) skins showed high reducing power and radical scavenging activities on 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (EC50 value of 1.57 mg/mL) and hydroxyl (EC50 value of 1.20 mg/mL). In this work, eight peptides were isolated from F7 and identified as Gly-Pro-Tyr (GPY, 335.31 Da), Gly-Pro-Thr-Gly-Glu (GPTGE, 459.47 Da), Pro-Phe-Gly-Pro-Asp (PFGPD, 531.52 Da), Gly-Pro-Thr-Gly-Ala-Lys (GPTGAKG, 586.65 Da), Pro-Tyr-Gly-Ala-Lys-Gly (PYGAKG, 591.69 Da), Gly-Ala-Thr-Gly-Pro-Gln-Gly (GATGPQG, 586.61 Da), Gly-Pro-Phe-Gly-Pro-Met (GPFGPM, 604.73 Da), and Tyr-Gly-Pro-Met (YGPM, 466.50 Da), respectively. Among them, PFGPD, PYGAKG, and YGPM exhibited strong radical scavenging activities on DPPH (EC50 values of 0.80, 3.02, and 0.72 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), hydroxyl (EC50 values of 0.81, 0.66, and 0.88 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), superoxide anion (EC50 values of 0.91, 0.80, and 0.73 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), and 2,2&prime, azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) cation (EC50 values of 0.86, 1.07, and 0.82 mg/mL for PFGPD, PYGAKG, and YGPM, respectively) in a positive concentration&ndash, activity relationship. Furthermore, PFGPD, PYGAKG, and YGPM could effectively reduce Fe3+ to Fe2+ and inhibit lipid peroxidation. Hence, eight collagen peptides from hydrolysate of Spanish mackerel skins might be served as antioxidant candidates for various industrial applications.

Lipid droplets have gained strong interest in recent years to comprehend how they function and coordinate with other parts of the cell. However, it remains challenging to study the regulation of lipid droplets in live preadipocytes using conventional microscopic techniques. In this paper, we study the effects of fatty acid stimulation and cell starvation on lipid droplets using optical diffraction tomography and Raman spectroscopy by measuring size, refractive index, volume, dry mass and degree of unsaturation. The increase of fatty acids causes an increase in the number and dry mass of lipid droplets. During starvation, the number of lipid droplets increases drastically, which are released to mitochondria to release energy. Studying lipid droplets under different chemical stimulations could help us understand the regulation of lipid droplets for metabolic disorders, such as obesity and diabetes. NRF (Natl Research Foundation, S’pore) Published version

Plant germplasm resources with natural resistance against globally important toxigenic Fusarium are inadequate. CWP2, a Fusarium genus-specific antibody, confers durable resistance to different Fusarium pathogens that infect cereals and other crops, producing mycotoxins. However, the nature of the CWP2 target is not known. Thus, investigation of the gene coding for the CWP2 antibody target will likely provide critical insights into the mechanism underlying the resistance mediated by this disease-resistance antibody. Immunoblots and mass spectrometry analysis of two-dimensional electrophoresis gels containing cell wall proteins from Fusarium graminearum (Fg) revealed that a glyoxal oxidase (GLX) is the CWP2 antigen. Cellular localization studies showed that GLX is localized to the plasma membrane. This GLX efficiently catalyzes hydrogen peroxide production; this enzymatic activity was specifically inhibited by the CWP2 antibody. GLX-deletion strains of Fg, F. verticillioides (Fv) and F. oxysporum had significantly reduced virulence on plants. The GLX-deletion Fg and Fv strains had markedly reduced mycotoxin accumulation, and the expression of key genes in mycotoxin metabolism was downregulated. This study reveals a single gene-encoded and highly conserved cellular surface antigen that is specifically recognized by the disease-resistance antibody CWP2 and regulates both virulence and mycotoxin biosynthesis in Fusarium species.

The Fusarium mycotoxin deoxynivalenol (DON) is typically controlled by fungicides. Here, we report DON detoxification using enzymes from the highly active Devosia strain D6-9 which degraded DON at 2.5 μg/min/108 cells. Strain D6-9 catabolized DON to 3-keto-DON and 3-epi-DON, completely removing DON in wheat. Genome analysis of three Devosia strains (D6-9, D17, and D13584), with strain D6-9 transcriptomes, identified three genes responsible for DON epimerization. One gene encodes a quinone-dependent DON dehydrogenase QDDH which oxidized DON into 3-keto-DON. Two genes encode the NADPH-dependent aldo/keto reductases AKR13B2 and AKR6D1 that convert 3-keto-DON into 3-epi-DON. Recombinant proteins expressed in Escherichia coli efficiently degraded DON in wheat grains. Molecular docking and site-directed mutagenesis revealed that residues S497, E499, and E535 function in QDDH's DON-oxidizing activity. These results advance potential microbial and enzymatic elimination of DON in agricultural samples and lend insight into the underlying mechanisms and molecular evolution of DON detoxification.

Trichothecenes are the most common mycotoxins contaminating small grain cereals worldwide. The C12,13 epoxide group in the trichothecenes was identified as a toxic group posing harm to humans, farm animals, and plants. Aerobic biological de-epoxidation is considered the ideal method of controlling these types of mycotoxins. In this study, we isolated a novel trichothecene mycotoxin-de-epoxidating bacterium, Desulfitobacterium sp. PGC-3-9, from a consortium obtained from the soil of a wheat field known for the occurrence of frequent Fusarium head blight epidemics under aerobic conditions. Along with MMYPF media, a combination of two antibiotics (sulfadiazine and trimethoprim) substantially increased the relative abundance of Desulfitobacterium species from 1.55% (aerobic) to 29.11% (aerobic) and 28.63% (anaerobic). A single colony purified strain, PGC-3-9, was isolated and a 16S rRNA sequencing analysis determined that it was Desulfitobacterium. The PGC-3-9 strain completely de-epoxidated HT-2, deoxynivalenol (DON), nivalenol and 15-acetyl deoxynivalenol, and efficiently eliminated DON in wheat grains under aerobic and anaerobic conditions. The strain PGC-3-9 exhibited high DON de-epoxidation activity at a wide range of pH (6&ndash, 10) and temperature (15&ndash, 50 &deg, C) values under both conditions. This strain may be used for the development of detoxification agents in the agriculture and feed industries and the isolation of de-epoxidation enzymes.

The contamination of food with Aspergillus flavus and subsequent aflatoxins is considered as one of the most severe safety problems in the world. The application of microorganisms and the produced bio-active compounds is considered as the most promising method for controlling foodborne pathogens and mycotoxins contamination both in pre- and post-harvest. Vt-7, identified as Enterobacter asburiae, was able to completely inhibit the growth of Aspergillus flavus (AF) and other seven important fungal pathogens by the production of volatiles. Additionally, it can also significantly inhibited AF infection on peanuts in storage, down-regulated the gene expression of aflatoxin biosynthesis and eventually prevented aflatoxins production. Scanning electron microscope further proved that Vt-7 volatiles prevented conidia germination of AF on peanut surface, and severely destroyed the conidia structure. Gas chromatography – tandem mass spectrometry revealed that two abundant compounds (1-Pentanol and Phenylethyl Alcohol) were involved in the volatile profiles. They showed great antagonistic activity against AF with minimal inhibitory concentration at 200 μL/L. Therefore, E. asburiae Vt-7, and volatiles 1-Pentanol and Phenylethyl Alcohol were effective agents in controlling AF and aflatoxins in peanut during storage. They will provide novel strategies for the application of microbe and bio-active compounds against fungal pathogens and mycotoxins in food and grains during storage.

Fumonisin B analogs, particularly FB1, FB2, and FB3, are major mycotoxins found in cereals. Single-chain fragment variable (scFv) antibodies represent a promising alternative immunoassay system. A phage-displayed antibody library derived from four monoclonal antibodies (mAbs) generated against FB1 was used to screen high binding affinity scFv antibodies; the best candidate was designated H2. Surface plasmon resonance measurements confirmed that the H2 scFv displayed a 82-fold higher binding affinity than its parent mAb. Direct competitive enzyme-linked immunosorbent assay demonstrated that the H2 antibody could competitively bind to free FB1, FB2, and FB3, with an IC50 of 0.11, 0.04, and 0.10 μM, respectively; it had no cross-reactivity to deoxynivalenol, nivalenol and aflatoxin. Validation assays with naturally contaminated samples revealed a linear relationship between the H2 antibody-based assay results and chemical analysis results, that could be expressed as y=1.7072x+5.5606 (R(2)=0.8883). Homology modeling of H2 revealed a favorable binding structure highly complementary to the three fumonisins. Molecular docking analyses suggested that the preferential binding of the H2 scFv to FB2 was due to the presence of a hydrogen radical in its R1 position, leading to a proper electrostatic matching and hydrophobic interaction. The H2 scFv antibody can be used for the rapid, accurate, and specific detection of fumonisin contamination in agricultural samples.

Four 2D coordination polymers (CPs) with different structures containing the multifunctional ligand 5-hydroxyisophthalate (5-OH-BDC2−), [Zn(5-OH-BDC)(btb)]·2H2O (1), [Cd(5-OH-BDC)(btp)(H2O)]·3H2O (2), [Cd(5-OH-BDC)(bth)2(H2O)]·H2O (3) and [Pb(5-OH-BDC)]·H2O (4) [btp=1, 3-bis(1,2,4-triazol-1-yl)propane, btb=1,4-bis(1,2,4-triazol-1-yl)butane, bth=1, 6-bis(1,2,4-triazol-1-yl)hexane] were obtained. 1–3 were synthesised hydrothermally, while 4 was obtained under ambient condition. The adjacent (2D→2D) polycatenated 2D layers of 1 polythread in a parallel manner to form an unusual 2D→3D polythreaded framework. 2 contains an undulated 2D (4, 4) network and further extends into an “embracing” double-layer structure through the C–H···π and π···π stacking interactions. 3 exhibits a non-interpenetrating 2D (4, 4)-network. 4 exhibits a 2D double-layered binodal (4, 4)-net containing oblong nanochannels with symbol (4363)2. Reversible dehydration–rehydration is observed in 1, 2 and 4, which fall within the category of “recoverable collapsing” and “guest-induced re-formation” frameworks, while 3 exhibits irreversible dehydration–rehydration behaviour. The solid state fluorescent properties of 1–4 have been investigated.

A sensitive and specific analytical method to detect ubiquitous aflatoxigenic Aspergillus pathogens is essential for monitoring and controlling aflatoxins. Four highly reactive chicken single-chain variable fragments (scFvs) against soluble cell wall proteins (SCWPs) from Aspergillus flavus were isolated by phage display. The scFv antibody AfSA4 displayed the highest activity toward both A. flavus and A. parasiticus and specifically recognized a surface target of their cell walls as revealed by immunofluorescence localization. Molecular modeling revealed a unique compact motif on the antibody surface mainly involving L-CDR2 and H-CDR3. As measured by surface plasmon resonance, AfSA4 fused to alkaline phosphatase had a higher binding capability and 6-fold higher affinity compared with AfSA4 alone. Immunoblot analyses showed that the fusion had good binding capacity to SCWP components from the two fungal species. Direct sandwich enzyme-linked immunosorbent assays with mouse antiaspergillus monoclonal antibody mAb2A8 generated in parallel as a capture antibody revealed that the detection limit of the two fungi was as low as 10(-3) μg/mL, 1000-fold more sensitive than that reported previously (1 μg/mL). The fusion protein was able to detect fungal concentrations below 1 μg/g of maize and peanut grains in both artificially and naturally contaminated samples, with at least 10-fold more sensitivity than that reported (10 μg/g) thus far. Thus, the fusion can be applied in rapid, simple, and specific diagnosis of Aspergillus contamination in field and stored food/feed commodities.

A recently isolated Fusarium population from maize in Belgium was identified as a new species, Fusarium temperatum. From a survey of Fusarium species associated with maize ear rot in nineteen provinces in 2009 in China, ten strains isolated from Guizhou and Hubei provinces were identified as F. temperatum. Morphological and molecular phylogenetic analyses based on the DNA sequences of individual translation elongation factor 1-alpha and β-tubulin genes revealed that the recovered isolates produced macroconidia typical of four-septate with a foot-shaped basal cell and belonged to F. temperatum that is distinctly different from its most closely related species F. subglutinans and others within Gibberella fujikuroi complex species from maize. All the strains from this newly isolated species were able to infect maize and wheat in field, with higher pathogenicity on maize. Mycotoxin determination of maize grains infected by the strains under natural field condition by ultra-high-performance liquid chromatography–tandem mass spectrometry and gas chromatography–mass spectrometry analyses showed that among fifteen mycotoxins assayed, two mycotoxins fumonisin B1 and B2 ranging from 9.26 to 166.89 μg/g were detected, with massively more FB2 mycotoxin (2.8- to 108.8-fold) than FB1. This mycotoxin production profile is different from that of the Belgian population in which only fumonisin B1 was barely detected in one of eleven strains assayed. Comparative analyses of the F. temperatum and F. subglutinans strains showed that the highest fumonisin producers were present among the F. temperatum population, which were also the most pathogenic to maize. These results suggested a need for proper monitoring and controlling this species in the relevant maize-growing regions.

Fusarium and its poisonous mycotoxins are distributed worldwide and are of particular interest in agriculture and food safety. A simple analytical method to detect pathogens is essential for forecasting diseases and controlling mycotoxins. This article describes a proposed method for convenient and sensitive detection of Fusarium pathogens that uses the fusion of single-chain variable fragment (scFv) and alkaline phosphatase (AP). A highly reactive scFv antibody specific to soluble cell wall-bound proteins (SCWPs) of F. verticillioides was selected from an immunized chicken phagemid library by phage display. The antibody was verified to bind on the surface of ungerminated conidiospores and mycelia of F. verticillioides. The scFv-AP fusion was constructed, and soluble expression in bacteria was confirmed. Both the antibody properties and enzymatic activity were retained, and the antigen-binding capacity of the fusion was enhanced by the addition of a linker. Surface plasmon resonance measurements confirmed that the fusion displayed 4-fold higher affinity compared with the fusion's parental scFv antibody. Immunoblot analyses showed that the fusion had good binding capacity to the components from SCWPs of F. verticillioides, and enzyme-linked immunosorbent assays revealed that the detection limit of the fungus was below 10(-2) μg mL(-1), superior to the scFv antibody. The fusion protein was able to detect fungal concentrations as low as 10(-3) mg g(-1) of maize grains in both naturally and artificially contaminated samples. Thus, the fusion can be applied in rapid and simple diagnosis of Fusarium contamination in field and stored grain or in food.

The stability of gold nanorods was assessed following coating with various charged or uncharged ligands, mostly peptides. Highly stable monodispersed gold nanorods were obtained by coating CTAB-stabilized gold nanorods with a pentapeptide with C-terminal ethylene glycol units (peptide-EG). UV-vis spectroscopy of these nanorods suspended in saline solutions indicated no signs of aggregation, and they were easily purified using size-exclusion chromatography. A more stringent measure of nanorod stability involved observing changes in the UV-vis absorbance of gold nanorods subjected to etching with cyanide. The λmax absorbance of peptide-EG coated nanorods red-shifted in etchant solution. The hypothesis that changes in the nanorod aspect ratio led to this red-shift was confirmed by TEM analysis, which showed pit formation along the transverse axis. The etching process was followed in solution using nanoparticle tracking analysis. The red-shift was shown to occur while the particles remained mono-dispersed, and so was not due to aggregation. Adding both etchant solution and peptide-EG to the nanorods was further shown to allow modulation of the Δλmax red-shift and increase the etchant resistance of peptide-EG nanorods. Thus, very stable gold nanorods can be produced using the peptide-EG coating approach and their optical properties modulated with etchant.

Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation.

Transcription factors play a central role in cell biology through binding to target DNA elements and regulating gene expression. In this study, we used the p53 tumour suppressor as a model transcription factor to develop an imaging based assay to measure DNA binding. The assay utilizes fluorescence imaging microscopy to detect labelled p53 bound to DNA coated on microbeads. We demonstrate the ability to multiplex the assay by interrogating simultaneous binding to variant DNA sequences present on tractable beads. Additionally, the assay measures activation of p53 for increased DNA binding by a known peptide in addition to reactivation of mutant p53 by a small molecule. It may therefore be adaptable to a high-content imaging screen for compounds capable of restoring the function of mutant p53 associated with cancer.

A lateral flow immunoassay (LFA) for rapid and sensitive quantitation of zearalenone (ZEN) in food and feed stuffs was developed, based on the availability of a new highly sensitive anti-ZEN monoclonal antibody. Compared to previously reported LFA, the established method allows quantitative determination of ZEN within the desirable dynamic range of 1–50 ng mL−1, corresponding to the recorded color intensity (CI) values of 65–9, with an IC50 value of 15 ng mL−1. The developed approach was then applied to a sample collection of thirty two cereal-based baby food, maize, wheat and feed samples, revealing that seven positive samples contained ZEN at concentrations ranging from 20 to 94 μg kg−1. The accuracy of the obtained results was confirmed by in-parallel LC–MS/MS analyses. The described assay format is capable of simple, rapid, cost-effective and robust on-site screening or remote quantitative analysis for ZEN, fulfilling the currently strictest regulation requirements for ZEN monitoring worldwide.

Fusarium graminearum clade species are among the main causative agents of Gibberella ear rot (GER) in maize and responsible for the various trichothecene mycotoxins accumulated in contaminated maize grains. In this study, a total of 620 isolates from diseased maize ears collected from 59 districts in 19 provinces throughout China, previously identified morphologically as Fusarium graminearum clade, was genetically characterized at the species level based on SCAR (Sequence Characterized Amplified Region) and for their potential capability of mycotoxin production using the genetic chemotyping assay. The results showed that 359 isolates were F. asiaticum (SCAR 5), which consisted of 97% nivalenol (NIV)-chemotypes, 0.8% 3-acetyldeoxynivalenol (3-ADON)-producing isolates and 2.2% 15-acetyldeoxynivalenol (15-ADON) producers, whereas the remaining 261 isolates were identified as F. graminearum sensu stricto (SCAR 1), all of which produced 15-ADON mycotoxins. This high proportion of NIV producers present in F. asiaticum is different from the chemotype patterns in F. asiaticum populations isolated from wheat and barley, where DON and its acetylated chemotypes were the predominant mycotoxins. Moreover, the majority of NIV producers (59.1%) and all the 3-ADON-producing strains were derived from the warmer regions in southern China, whereas most of the 15-ADON-producing strains (78.4%) were isolated from the colder regions in northern China. Our study is the first report of NIV chemotypes of F. asiaticum and 15-ADON chemotypes of F. graminearum sensu stricto that were associated with the GER of maize in China.

Combined analyses of the natural occurrence of fusarium head blight (FHB), mycotoxins and mycotoxin-producing isolates of Fusarium spp. in fields of wheat revealed FHB epidemics in 12 of 14 regions in Hubei in 2009. Mycotoxin contamination ranged from 0·59 to 15·28 μg g−1 in grains. Of the causal agents associated with symptoms of FHB, 84% were Fusarium asiaticum and 9·5% were Fusarium graminearum, while the remaining 6·5% were other Fusarium species. Genetic chemotyping demonstrated that F. asiaticum comprised deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON) and nivalenol (NIV) producers, whereas F. graminearum only included DON and 15-AcDON producers. Compared with the chemotype patterns in 1999, there appeared to be a modest shift towards 3-AcDON chemotypes in field populations during the following decade. However, isolates genetically chemotyped as 3-AcDON were present in all regions, whereas the chemical 3-AcDON was only detected in three of the 14 regions where 3-AcDON accounted for 15–20% of the DON and acetylated forms. NIV mycotoxins were detected in seven regions, six of which also yielded NIV chemotypes. The number of genetic 3-AcDON producers was positively correlated with amounts of total mycotoxins (DON, NIV and acetylated forms) or DON in wheat grains. Chemical analyses of wheat grains and rice cultures inoculated with different isolates from the fields confirmed their genetic chemotypes and revealed a preferential biosynthesis of 3-AcDON and 4-AcNIV in rice. These findings suggest the importance of chemotyping coupled with species identification for improved prediction of mycotoxin contamination in wheat.

The Fusarium graminearum species complex (Fg complex) consists of phylogenetically distinct species some of which cannot be discriminated based on their morphology. Their chemotypes and geographic distributions are dramatically different, and these highlight the challenges that Fusarium head blight (FHB) poses to plant disease specialists and plant breeders, thereby requiring that quarantine officials employ molecular diagnostic tools in their active surveillance programs. Molecular marker technologies play essential roles in species identification of the Fg complex, and they are being used widely to assess the genetic diversity of the clade. The utility, applicability and limitations of molecular methods for assessing the population structure and genetic diversity within the Fg complex are discussed with suitable examples. Knowledge gained from these studies will provide a baseline for monitoring changes in FHB pathogen diversity and mycotoxin potential over time, both of which are critical to the ultimate control and elimination of this economically devastating disease.

Porous crystalline SnO 2 thin films were electrodeposited from an oxygen-saturated acid aqueous solution of SnCl 2 containing different amounts of butyl rhodamine B (BRhB) at 70 °C. BRhB can not only be dissolved in the acid deposition solution due to its amidocyanogen substitute, where HCl was added to suppress hydrolysis of SnCl 2 , but also be adsorbed on the surface of SnO 2 through its carbonate substitute. Therefore, it was used as a structure-directing agent to control the growth of SnO 2 crystals and then the crystalline structure and surface morphology of the deposited film. The electrodeposited thin films show porous morphology and rutile-type SnO 2 crystalline structure due to the effects of BRhB on the growth, and these structural features can be adjusted by changing the added amount of BRhB. The SnO 2 thin film electrodeposited with addition of BRhB exhibits electrocatalytic characteristic enhancement on oxidation of phenol due to its porous structure.

One homochiral 1D coordination polymer [Cu(ATIBDC)(2,2′-bipy)]·3H2O·CH3OH (1) and three achiral 1D coordination polymers: [Cd(ATIBDC)(2,2′-bipy)(H2O)]·3H2O (2), [Cd(ATIBDC)(phen)(H2O)]·4H2O (3), and [Mn(ATIBDC)(phen)2]·5H2O (4) have been synthesized and characterized (H2ATIBDC=5-amino-2,4,6-triiodoisophthalic acid, 2,2′-bipy=2,2′-bipyridine, and phen=1,10-phenanthroline). Extended high dimensional network architectures are further constructed with the help of weak secondary interactions, such as hydrogen bonding, aromatic stacking, and halogen bonding (C–I…π and C–I…N/O). Complex 1 crystallizes in the monoclinic system with chiral space group P2(1) and exhibits a right-handed 21 helical chain structure. The homochirality of 1 was confirmed by CD spectrum. Interestingly, two new configurations of decameric water cluster are found in 3 and 4. The acyclic tetrameric cluster (H2O)3(CH3OH) in 1 and (H2O)4 in 2 array into highly ordered helical infinite chains. Thermal stabilities of all the complexes have been studied. Solid state fluorescent properties of the Cd(II) complexes have been explored.

Porous SnO 2 nanocrystalline thin films were successfully electrodeposited from an oxygen-saturated acid aqueous solution of SnCl 2 containing different concentrations of butyl-rhodamine B (BRhB) at 70 °C. BRhB with substitute of amidocyanogen can be dissolved in the acid deposition solution, where HCl was added to suppress hydrolysis of SnCl 2 . So it was used as a structure-directing agent to promote the crystal growth of SnO 2 . The formed porous morphology and tetragonal rutile crystalline structure of the electrodeposited thin films were controlled by the addition of BRhB with different amounts.

A novel low temperature method was used to prepare the mesoporous carbon (MC) counter electrode (CE) on indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) for flexible dye-sensitized solar cells (DSSCs). The obtained flexible MC CEs with carbon loading of 280 μg cm −2 were characterized by SEM, XRD and electrochemical impedance. The light-to-electricity conversion efficiency of the DSSC fabricated with the prepared flexible MC CE was 86% of that of DSSC based on the decomposited Pt CE.

TiO 2 colloid was prepared by the sol–gel method and was bladed on transparent conduction glass to made nanoporous electrode. The impedance performance of TiO 2 electrode was studied at various bias potential. A simplified equivalent circuit was proposed to investigate the charge transport impedance of TiO 2 film and good fitting results were obtained.

Natural resistance of wheat against Fusarium head blight (FHB) is inadequate and new strategies for controlling the disease are required. Chitin synthases that catalyze chitin biosynthesis would be an ideal target for antifungal agents. In this study, a class I chitin synthase gene (CHS1) from Fusarium asiaticum, the predominant species of FHB pathogens on wheat in China, was functionally disrupted via Agrobacterium tumefaciens-mediated transformation. Specific disruption of the CHS1 gene resulted in a 58% reduction of chitin synthase activity, accompanied by decreases of 35% in chitin content, 22% in conidiation, and 16% in macroconidium length. The Deltachs1 mutant strain had a growth rate comparable to that of the wild-type on PDA medium but had a 35% increase in the number of nuclear cellulae and exhibited a remarkably increased sensitivity to osmosis stresses. Electron microscopy revealed substantial changes occurring in cell wall structures of the macroconidium, ascospore, and mycelium, with the most profound changes in the mycelium. Furthermore, the Deltachs1 mutant displayed significantly reduced pathogenicity on wheat spikes and seedlings. Re-introduction of a functional CHS1 gene into the Deltachs1 mutant strain restored the wild-type phenotype. These results reveal an important in vivo role played by a CHS1 gene in a FHB pathogen whose mycelial chitin could serve as a target for controlling the disease.

This paper elaborates on approaches of synthesis of Au and Ag nanoparticles (NPs), deposition of colloid onto glass substrate and encapsulation of NPs with silicon dioxide (SiO2) thin shell. As one important bio application of metallic nanoparticles, both solution-based and substrate-based fluorescence enhancement tests are demonstrated.

Fusarium mycotoxins directly accumulated in grains during the infection of wheat and other cereal crops by Fusarium head blight (FHB) pathogens are detrimental to humans and domesticated animals. Prevention of the mycotoxins via the development of FHB-resistant varieties has been a challenge due to the scarcity of natural resistance against FHB pathogens. Various antibodies specific to Fusarium fungi and mycotoxins are widely used in immunoassays and antibody-mediated resistance in planta against Fusarium pathogens has been demonstrated. Antibodies fused to antifungal proteins have been shown to confer a very significantly enhanced Fusarium resistance in transgenic plants. Thus, antibody fusions hold great promise as an effective tool for the prevention of mycotoxin contaminations in cereal grains. This review highlights the utilization of protective antibodies derived from phage display to increase endogenous resistance of wheat to FHB pathogens and consequently to reduce mycotoxins in field. The role played by Fusarium-specific antibody in the resistance is also discussed.

Solid-state dye-sensitized solar cells based on nanocrystalline TiO2 thin film with the structures TiO2/dye/CuI/Pt and TiO2/dye/In situ CuI/CuI/Pt were developed in order to compare the use of In situ deposited CuI (In situ CuI). Porosity of the screen-printed nanoporous TiO2 thin film was enhanced by the addition of polystyrene balls. Evidence of decrease in interfacial resistance was observed by electrochemical impedance measurement for the device with In situ deposited CuI as compared to that without In situ deposited CuI as hole conductor. This was attributed to good interfacial contacts and better charge transfer between CuI and dye-sensitized TiO2 nanoparticles, which resulted in the enhancement of power conversion efficiency from 0.058 to 1.01%. Copyright © 2008 John Wiley & Sons, Ltd.

The screen-printed nanoporous TiO 2 thin film was employed to fabricate dye-sensitized solid-state solar cells using CuI as hole-transport materials. The solar cell based on nanoporous TiO 2 thin film with large pores formed by the addition of polystyrene balls with diameter of 200 nm to the TiO 2 paste exhibits photovoltaic performance enhancement, which is attributed to the good contact of CuI with surface of dye-sensitized thin film due to easy penetration of CuI in the film with large pores.

The genetic diversity and pathogenicity of isolates of Fusarium graminearum and F. asiaticum isolated from wheat heads in China were examined and compared with those of isolates of F. graminearum, F. asiaticum and F. meridionale from Europe, USA and Nepal. Genetic diversity was assessed by SSCP (single strand conformation polymorphism) and AFLP (amplified fragment length polymorphism) analysis and by molecular chemotyping. SSCP analysis of the Fg16F/Fg16R PCR amplicon differentiated F. graminearum, F. asiaticum and F. meridionale and revealed three haplotypes among sequence-characterized amplified region (SCAR) type 1 F. graminearum isolates. AFLP analysis showed a high level of genetic diversity and clustered the majority of Chinese isolates in one group along with other isolates of Asian origin. The second cluster contained F. graminearum isolates from China, Europe and the USA. Of the Chinese isolates, 79% were F. asiaticum and 81% of these were of the 3-AcDON chemotype, with only 9·5% of either chemotype 15-AcDON or NIV. All the Chinese and USA isolates of F. graminearum were 15-AcDON, whereas among the isolates from Europe, 21% were NIV and 8% were 3-AcDON chemotype. No evidence was found for possible differences in aggressiveness between F. graminearum and F. asiaticum. Highly aggressive isolates were present in each region and no evidence was found for any association between aggressiveness and geographical origin or chemotype among the isolates examined. No difference was observed in pathogenicity towards wheat seedlings between Chinese isolates and those from Europe, the USA or Nepal.

A large number of isolates from the Fusarium graminearum clade representing all regions in China with a known history of Fusarium head blight (FHB) epidemics in wheat were assayed using PCR to ascertain their trichothecene mycotoxin chemotypes and associated phylogenetic species and geographical distribution. Of the 299 isolates assayed, 231 are from F. asiaticum species lineage 6, which produce deoxynivalenol and 3-acetyldeoxynivalenol (3-AcDON); deoxynivalenol and 15-acetyldeoxynivalenol (15-AcDON); and nivalenol and 4-acetylnivalenol (NIV) mycotoxins, with 3-AcDON being the predominant chemotype. Ninety-five percent of this species originated from the warmer regions where the annual average temperatures were above 15 degrees C, based on the climate data of 30 y during 1970-1999. However, 68 isolates within F. graminearum species lineage 7 consisted only of 15-AcDON producers, 59% of which were from the cooler regions where the annual average temperatures were 15 degrees C or lower. Identification of a new subpopulation of 15-AcDON producers revealed a molecular distinction between F. graminearum and F. asiaticum that produce 15-AcDON. An 11-bp repeat is present in F. graminearum within their Tri7 gene sequences but is absent in F. asiaticum, which could be directly used for differentiating the two phylogenetic species of the F. graminearum clade.

Controlling toxigenic Fusarium graminearum (FG) is challenging. A bacterial strain (S76-3, identified as Bacillus amyloliquefaciens) that was isolated from diseased wheat spikes in the field displayed strong antifungal activity against FG. Reverse-phase high performance liquid chromatography and electrospray ionization mass spectrometry analyses revealed that S76-3 produced three classes of cyclic lipopeptides including iturin, plipastatin and surfactin. Each class consisted of several different molecules. The iturin and plipastatin fractions strongly inhibited FG; the surfactin fractions did not. The most abundant compound that had antagonistic activity from the iturin fraction was iturin A (m/z 1043.35); the most abundant active compound from the plipastatin fraction was plipastatin A (m/z 1463.90). These compounds were analyzed with collision-induced dissociation mass spectrometry. The two purified compounds displayed strong fungicidal activity, completely killing conidial spores at the minimal inhibitory concentration range of 50 µg/ml (iturin A) and 100 µg/ml (plipastatin A). Optical and fluorescence microscopy analyses revealed severe morphological changes in conidia and substantial distortions in FG hyphae treated with iturin A or plipastatin A. Iturin A caused leakage and/or inactivation of FG cellular contents and plipastatin A caused vacuolation. Time-lapse imaging of dynamic antagonistic processes illustrated that iturin A caused distortion and conglobation along hyphae and inhibited branch formation and growth, while plipastatin A caused conglobation in young hyphae and branch tips. Transmission electron microscopy analyses demonstrated that the cell walls of conidia and hyphae of iturin A and plipastatin A treated FG had large gaps and that their plasma membranes were severely damaged and separated from cell walls.

We report a real-time method to determine the size, i.e. diameter, and refractive index of single gold nanoparticles using an optofluidic chip, which consists of a quasi-Bessel beam optical chromatography. The tightly focused (∼ 0.5 μm) quasi-Bessel beam with low divergence (NA ∼ 0.04) was used to trap sub-100 nm gold nanoparticles within a long trapping distance of 140 μm. In the experiment, 60 to 100 nm gold nanoparticles were separated efficiently with at least 18 μm. The diameter and refractive index (real and imaginary) of single gold nanoparticles were measured at high resolutions with respect to the trapping distance, i.e. 0.36 nm/μm, 0.003/μm and 0.0016/μm, respectively. NRF (Natl Research Foundation, S’pore) Published version

Fusarium head blight (FHB) in wheat and other small grain cereals is a globally devastating disease caused by toxigenic Fusarium pathogens. Controlling FHB is a challenge because germplasm that is naturally resistant against these pathogens is inadequate. Current control measures rely on fungicides. Here, an antibody fusion comprised of the Fusarium spp.-specific recombinant antibody gene CWP2 derived from chicken, and the endochitinase gene Ech42 from the biocontrol fungus Trichoderma atroviride was introduced into the elite wheat cultivar Zhengmai9023 by particle bombardment. Expression of this fusion gene was regulated by the lemma/palea-specific promoter Lem2 derived from barley; its expression was confirmed as lemma/palea-specific in transgenic wheat. Single-floret inoculation of independent transgenic wheat lines of the T3 to T6 generations revealed significant resistance (type II) to fungal spreading, and natural infection assays in the field showed significant resistance (type I) to initial infection. Gas chromatography-mass spectrometry analysis revealed marked reduction of mycotoxins in the grains of the transgenic wheat lines. Progenies of crosses between the transgenic lines and the FHB-susceptible cultivar Huamai13 also showed significantly enhanced FHB resistance. Quantitative real-time PCR analysis revealed that the tissue-specific expression of the antibody fusion was induced by salicylic acid drenching and induced to a greater extent by F. graminearum infection. Histochemical analysis showed substantial restriction of mycelial growth in the lemma tissues of the transgenic plants. Thus, the combined tissue-specific and pathogen-inducible expression of this Fusarium-specific antibody fusion can effectively protect wheat against Fusarium pathogens and reduce mycotoxin content in grain.

Trehalose 6-phosphate synthase (TPS1) and trehalose 6-phosphate phosphatase (TPS2) are required for trehalose biosynthesis in yeast and filamentous fungi, including Fusarium graminearum. Three null mutants Δtps1, Δtps2 and Δtps1-Δtps2, each carrying either a single deletion of TPS1 or TPS2 or a double deletion of TPS1-TPS2, were generated from a toxigenic F. graminearum strain and were not able to synthesize trehalose. In contrast to its reported function in yeasts and filamentous fungi, TPS1 appeared dispensable for development and virulence. However, deletion of TPS2 abolished sporulation and sexual reproduction; it also altered cell polarity and ultrastructure of the cell wall in association with reduced chitin biosynthesis. The cell polarity alteration was exhibited as reduced apical growth and increased lateral growth and branching with increased hyphal and cell wall widths. Moreover, the TPS2-deficient strain displayed abnormal septum development and nucleus distribution in its conidia and vegetative hyphae. The Δtps2 mutant also had 62% lower mycelial growth on potato dextrose agar and 99% lower virulence on wheat compared with the wild-type. The Δtps1, Δtps2 and Δtps1-Δtps2 mutants synthesized over 3.08-, 7.09- and 2.47-fold less mycotoxins, respectively, on rice culture compared with the wild-type. Comparative transcriptome analysis revealed that the Δtps1, Δtps2 and Δtps1-Δtps2 mutants had 486, 1885 and 146 genotype-specific genes, respectively, with significantly changed expression profiles compared with the wild-type. Further dissection of this pathway will provide new insights into regulation of fungal development, virulence and trichothecene biosynthesis.

Fusarium verticillioides is the primary causal agent of Fusarium ear and kernel rot in maize, producing fumonisin mycotoxins that are toxic to humans and domestic animals. Rapid detection and monitoring of fumonisin-producing fungi are pivotally important for the prevention of mycotoxins from entering into food/feed products. Chicken-derived single-chain variable fragments (scFvs) against cell wall-bound proteins from F. verticillioides were isolated from an immunocompetent phage display library. Comparative phage enzyme-linked immunosorbant assays (ELISAs) and sequencing analyses identified four different scFv antibodies with high sensitivity. Soluble antibody ELISAs identified two highly sensitive scFv antibodies, FvCA3 and FvCA4, with the latter being slightly more sensitive. Three-dimensional modeling revealed that the FvCA4 may hold a better overall structure with CDRH3, CDRL1 and CDRL3 centered in the core region of antibody surface compared with that of other scFvs. Immunofluorescence labeling revealed that the binding of FvCA4 antibody was localized to the cell walls of conidiospores and hyphae of F. verticillioides, confirming the specificity of this antibody for a surface target. This scFv antibody was able to detect the fungal mycelium as low as 10(-2) μg/mL and contaminating mycelium at a quantity of 10(-2) mg/g maize. This is the first report that scFv antibodies derived from phage display have a wide application for rapid and accurate detection and monitoring of fumonisin-producing pathogens in agricultural samples.

An isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with a fast sample preparation using homemade clean-up cartridges was developed for simultaneous determination of co-occurring mycotoxins exemplified with aflatoxin B1 (AFB1) and T-2 toxin (T-2) in representative biomatrices of rat plasma, heart, liver, kidney, spleen, lung and brain in a total run time of 7 min. The established approach using stable internal standards of [C-13(17)]-AFB1 and [C-13(24)]-T-2 was extensively validated by determining the specificity, linearity (R-2 >= 0.9990), sensitivity (lower limit of quantitation at 0.05 ng mL(-1)), accuracy (70.9-107.7%), precision (RSD = 70.8%). Based on this methodological advance, the subsequent kinetics and tissue distribution after oral administration of 0.5 mg kg(-1) b.w. of both AFB1 and T-2 in rats were thoroughly studied. As revealed, both AFB1 and T-2 were rapidly eliminated with the half-life time (t(1/2)) in plasma of 8.44 +/- 4.02 h and 8.12 +/- 4.05 h, respectively. Moreover, AFB1 accumulated in all organs where the highest concentration was observed in liver (1.34 mu g kg(-1)), followed by kidney (0.76 mu g kg(-1)). Notably, only low levels of T-2 were observed in spleen (0.70 mu g kg(-1)) and in liver (0.15 mu g kg(-1)). The achieved data as supporting evidence would substantially promote the practical application of the proposed LC-MS/MS method for in vivo toxicokinetics and toxicity studies of co-occurring mycotoxins imitating natural incidence in rat system.

Two low-dimensional oxime-containing Schiff base copper(I/II) complexes with iodine–copper cluster [Cu2I4]2− bridges, namely, {[CuII4I3(pop)4]2(CuI2I4)}·(CH3CN)2·H2O (2) and [CuII4I2(pop)4(CuI2I4)·(CH3CN)]n (3) (Hpop = 2-(hydroxyimino)-N′-[1-(2-yridyl)ethylidene]propanehydrazone), have been synthesized from the reaction of [2 × 2] grid-like compound {[CuIII(pop)]4}2·4H2O (1) with equivalent CuI2I2 (iodine–copper clusters) under solvothermal conditions and characterized by elemental analysis (EA), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and X-ray single-crystal/powder diffraction. The results show that 2 is a 0-D discrete structure from an assembly of one [Cu2I4]2− unit and two [2 × 2] molecular grids (1) via μ3-I atoms coordinating to CuI/CuII atoms. However, compound 3 presents a 1-D wave-like chain, which is constructed by coordination of μ2-I atoms from [CuI2I4]2− units with CuII atoms in [2 × 2] molecular grids (1). Moreover, catalytic experiments demonstrated that compounds 2 and 3 have promising visible-light-driven catalytic activity in degrading various organic dyes.

Gold nanorods (AuNRs) possess unique optical properties which make them good contrast agents for optical microscopy. Their longitudinal plasmon resonance peak can be easily tuned from red to near infrared wavelength by increasing their aspect ratio to match the wavelengths of different imaging modalities. AuNRs are also stronger scatterers of light as compared with gold nanospheres. Nevertheless what sets them apart from other gold nanoparticles is their strong multiphoton luminescence. AuNRs are therefore being increasingly used as contrast agents for multiphoton microscopy of biological samples. In this study, control of the longitudinal resonance peak of gold nanorods is investigated with comparison of two chemical synthesis approaches. Both based on a seed-mediated method, one approach is to tune the aspect ratio through manipulation of the ratio of gold seeds to gold salt and the other is through variation of the volume of hydrochloric acid. The synthesized gold nanorods were made biocompatible by replacing the cytotoxic cetyltrimethylammonium bromide (CTAB) molecules with either silica (SiO2) or polyethylene glycol (PEG). Multiphoton imaging of gold nanorods taken up by cells was demonstrated and the effect of PEG chain length on passive uptake of gold nanorods by cells is discussed.

By modulating the synthetic strategy based on changing the cosolvent in the synthesis, the aqueous medium assembly of lead(II) with H2ATBIP in the presence of different cosolvents, N,N-dimethylacetamide (DMA), methanol (CH3OH) or N,N-dimethylformamide (DMF), leads to a family of three lead(II) coordination polymers: [Pb(ATBIP)(H2O)2]·2H2O (1), [Pb(ATBIP)(H2O)(CH3OH)]·H2O (2) and [Pb(ATBIP)(H2O)(DMF)]·H2O (3) [H2ATBIP = 5-amino-2,4,6-tribromoisophthalic acid]. Complex 1 exhibits an interesting double chain structure with [Pb2(OH2)2] as the secondary building unit (SBU), which further assembles into a 3D supramolecular framework through the C–Br⋯Br halogen bonds and hydrogen bonds. Furthermore, the discrete water octamer (H2O)8 is found. The cosolvents, DMF and CH3OH, which simultaneously act as the coordinated small molecules, have significant influences on the formation of different crystalline architectures. Complex 2 features a 2D network constructed by the 21 helical carboxylate-bridged Pb(II) chains [Pb2(COO)2]n (SBUs) linked by the ligand ATBIP2−. The intralayer C–Br⋯Br halogen bond is found and a 3D supramolecular framework is formed by the interlayer hydrogen bonds. Complex 3 crystallizes in the chiral space group P41212 and possesses a 2D (4,4)-homochiral layer built from the centrosymmetrical SBU [Pb2(COO)2] bridged by the ligand ATBIP2−. The interlayer hydrogen bonds further extend the chiral layers in 3 into a 3D supramolecular homochiral framework. The coordination modes of the ligand ATBIP2− are greatly dependent on the cosolvents. Complex 3 loses crystallinity in the air and forms the material [Pb(ATBIP)(DMF)] (3A). Thermal stability and solid state fluorescent properties of 1, 2 and 3A have been studied. The second harmonic generation (SHG) property of 3A is also studied.

A large number of Fusarium graminearum and F. asiaticum isolates were collected from wheat spikes from all regions in China with a history of fusarium head blight (FHB) epidemics. Isolates were analysed to investigate their genetic diversity and geographic distribution. Sequence characterized amplified region (SCAR) analyses of 437 isolates resolved both species, with 21% being F. graminearum (SCAR type 1) and 79% being F. asiaticum (SCAR type 5). AFLP profiles clearly resolved two groups, A and B, that were completely congruent with both species. However, more diversity was detected by AFLP, revealing several subgroups within each group. In many cases, even for isolates from the same district, AFLP haplotypes differed markedly. Phylogenetic analyses of multilocus DNA sequence data indicated that all isolates of SCAR type 1, AFLP group A were F. graminearum, whilst isolates of SCAR type 5, AFLP group B were F. asiaticum, demonstrating that it is an efficient method for differentiating these two species. Both species seem to have different geographic distributions within China. Fusarium graminearum was mainly obtained from wheat growing in the cooler regions where the annual average temperature was 15°C or lower. In contrast, the vast majority of F. asiaticum isolates were collected from wheat growing in the warmer regions where the annual average temperature is above 15°C and where FHB epidemics occur most frequently. This is the first report of the distribution of, and genetic diversity within, F. graminearum and F. asiaticum on wheat spikes throughout China.

Protein methylation is one of the most important post-translational modifications. Typically methylation occurs on arginine or lysine residues in the protein sequence. In the biological system, methylation is catalyzed by enzymes, and should be involved in modification of heavy metals, regulation of gene expression, regulation of protein function, and RNA metabolism. Thus the prediction of methylation sites plays a crucial role. As we know, traditional experiment approaches to predict the sites are accurate, but that are always labor-intensive and time-consuming. Thus, it is common to see that computational methods receive increasingly attentions due to their convenience and fast speed in recent years. In this study, we develop a computational approach to predict the performance of methylarginine and methyllysine sites. First, a new encoding schema as called the CKASSP is used in our method. Then, the support vector machine (SVM) algorithm is used as a predictor. Experimental results show that our method can obtain average prediction accuracy of 87.46%, sensitivity of 99.09%, specificity of 86.89% for arginine methylation sites, and average prediction accuracy of 88.78%, sensitivity of 93.75%, specificity of 81.79% for lysine methylation sites as well, which is better than those of other state-of-art predictors. The online service is implemented by java 1.4.2 and is freely available at http://202.198.129.219:8080/cksaap_methsite.