Structure, substrate binding and activity of a unique AAA+ protein: the BrxL phage restriction factor.

Bacteriophage exclusion ('BREX') systems are multi-protein complexes encoded by a variety of bacteria and archaea that restrict phage by an unknown mechanism. One BREX factor, termed BrxL, has been noted to display sequence similarity to various AAA+ protein factors including Lon protease. In this study we describe multiple CryoEM structures of BrxL that demonstrate it to be a chambered, ATP-dependent DNA binding protein. The largest BrxL assemblage corresponds to a dimer of heptamers in the absence of bound DNA, versus a dimer of hexamers when DNA is bound in its central pore. The protein displays DNA-dependent ATPase activity, and ATP binding promotes assembly of the complex on DNA. Point mutations within several regions of the protein-DNA complex alter one or more in vitro behaviors and activities, including ATPase activity and ATP-dependent association with DNA. However, only the disruption of the ATPase active site fully eliminates phage restriction, indicating that other mutations can still complement BrxL function within the context of an otherwise intact BREX system. BrxL displays significant structural homology to MCM subunits (the replicative helicase in archaea and eukaryotes), implying that it and other BREX factors may collaborate to disrupt initiation of phage DNA replication.

A Safety Approach for Improving Security - Effective Coordination Strategies at the Airport Security Screening Checkpoint.

OBJECTIVE: This study aimed to analyze effective teamwork at security checkpoints by investigating how security crews communicate in different (routine and threat) situations. BACKGROUND: Working at an airport security screening checkpoint is challenging. Although tasks and processes are highly regulated and standardized due to legal requirements, security screeners must be trained to deal with unforeseen threat situations involving high levels of uncertainty. Therefore, security crews need to engage in flexible and adaptive coordination according to the situation and circumstances. METHOD: We conducted a field study with 20 airport security screening crews comprising 100 security screeners. Teamwork in terms of interaction between crew members was measured, differentiating between proactive "push" communication and information on request representing "pull" communication. Furthermore, non-task related communication was assessed. RESULTS: While crews showed non-task related communication more in routine situations, both task-related "push" and "pull" communication occurred more in threat situations. In terms of team performance, we could show significant positive effects of proactive "push" communication and non-task related interaction in threat situations. CONCLUSION: Our results underscore the specific setting of airport security screening and the challenges that arise for teamwork. This study investigates professional screeners and passengers in the field. In contrast to other high-risk areas, security crews are confronted with a third party that complicates coordination strategies considered effective in previous studies. APPLICATION: Our findings recommend situation-specific communication strategies for practical training for airport security screening crews.

Immune protection against reinfection with nonprimate hepacivirus.

Hepatitis C virus (HCV) displays a restricted host species tropism and only humans and chimpanzees are susceptible to infection. A robust immunocompetent animal model is still lacking, hampering mechanistic analysis of virus pathogenesis, immune control, and prophylactic vaccine development. The closest homolog of HCV is the equine nonprimate hepacivirus (NPHV), which shares similar features with HCV and thus represents an animal model to study hepacivirus infections in their natural hosts. We aimed to dissect equine immune responses after experimental NPHV infection and conducted challenge experiments to investigate immune protection against secondary NPHV infections. Horses were i.v. injected with NPHV containing plasma. Flow cytometric analysis was used to monitor immune cell frequencies and activation status. All infected horses became viremic after 1 or 2 wk and viremia could be detected in two horses for several weeks followed by a delayed seroconversion and viral clearance. Histopathological examinations of liver biopsies revealed mild, periportally accentuated infiltrations of lymphocytes, macrophages, and plasma cells with some horses displaying subclinical signs of hepatitis. Following viral challenge, an activation of equine immune responses was observed. Importantly, after a primary NPHV infection, horses were protected against rechallenge with the homologous as well as a distinct isolate with only minute amounts of circulating virus being detectable.

Differential Infection Patterns and Recent Evolutionary Origins of Equine Hepaciviruses in Donkeys.

The hepatitis C virus (HCV) is a major human pathogen. Genetically related viruses in animals suggest a zoonotic origin of HCV. The closest relative of HCV is found in horses (termed equine hepacivirus [EqHV]). However, low EqHV genetic diversity implies relatively recent acquisition of EqHV by horses, making a derivation of HCV from EqHV unlikely. To unravel the EqHV evolutionary history within equid sister species, we analyzed 829 donkeys and 53 mules sampled in nine European, Asian, African, and American countries by molecular and serologic tools for EqHV infection. Antibodies were found in 278 animals (31.5%), and viral RNA was found in 3 animals (0.3%), all of which were simultaneously seropositive. A low RNA prevalence in spite of high seroprevalence suggests a predominance of acute infection, a possible difference from the mostly chronic hepacivirus infection pattern seen in horses and humans. Limitation of transmission due to short courses of infection may explain the existence of entirely seronegative groups of animals. Donkey and horse EqHV strains were paraphyletic and 97.5 to 98.2% identical in their translated polyprotein sequences, making virus/host cospeciation unlikely. Evolutionary reconstructions supported host switches of EqHV between horses and donkeys without the involvement of adaptive evolution. Global admixture of donkey and horse hepaciviruses was compatible with anthropogenic alterations of EqHV ecology. In summary, our findings do not support EqHV as the origin of the significantly more diversified HCV. Identification of a host system with predominantly acute hepacivirus infection may enable new insights into the chronic infection pattern associated with HCV. IMPORTANCE: The evolutionary origins of the human hepatitis C virus (HCV) are unclear. The closest animal-associated relative of HCV occurs in horses (equine hepacivirus [EqHV]). The low EqHV genetic diversity implies a relatively recent acquisition of EqHV by horses, limiting the time span for potential horse-to-human infections in the past. Horses are genetically related to donkeys, and EqHV may have cospeciated with these host species. Here, we investigated a large panel of donkeys from various countries using serologic and molecular tools. We found EqHV to be globally widespread in donkeys and identify potential differences in EqHV infection patterns, with donkeys potentially showing enhanced EqHV clearance compared to horses. We provide strong evidence against EqHV cospeciation and for its capability to switch hosts among equines. Differential hepacivirus infection patterns in horses and donkeys may enable new insights into the chronic infection pattern associated with HCV.

Single-component supported lipid bilayers probed using broadband nonlinear optics.

Broadband SFG spectroscopy is shown to offer considerable advantages over scanning systems in terms of signal-to-noise ratios when probing well-formed single-component supported lipid bilayers formed from zwitterionic lipids with PC headgroups. The SFG spectra obtained from bilayers formed from DOPC, POPC, DLPC, DMPC, DPPC and DSPC show a common peak at ∼2980 cm-1, which is subject to interference between the C-H and the O-H stretches from the aqueous phase, while membranes having transition temperatures above the laboratory temperature produce SFG spectra with at least two additional peaks, one at ∼2920 cm-1 and another at ∼2880 cm-1. The results validate spectroscopic and structural data from SFG experiments utilizing asymmetric bilayers in which one leaflet differs from the other in the extent of deuteration. Differences in H2O-D2O exchange experiments reveal that the lineshapes of the broadband SFG spectra are significantly influenced by interference from OH oscillators in the aqueous phase, even when those oscillators are not probed by the incident infrared light in our broadband setup. In the absence of spectral interference from the OH stretches of the solvent, the alkyl chain terminal methyl group of the bilayer is found to be tilted at an angle of 15° to 35° from the surface normal.

Ion Channel Function and Cross-Species Determinants in Viral Assembly of Nonprimate Hepacivirus p7.

UNLABELLED: Nonprimate hepacivirus (NPHV), the closest homolog of hepatitis C virus (HCV) described to date, has recently been discovered in horses. Even though the two viruses share a similar genomic organization, conservation of the encoded hepaciviral proteins remains undetermined. The HCV p7 protein is localized within endoplasmic reticulum (ER) membranes and is important for the production of infectious particles. In this study, we analyzed the structural and functional features of NPHV p7 in addition to its role during virus assembly. Three-dimensional homology models for NPHV p7 using various nuclear magnetic resonance spectroscopy (NMR) structures were generated, highlighting the conserved residues important for ion channel function. By applying a liposome permeability assay, we observed that NPHV p7 exhibited liposome permeability features similar to those of HCV p7, indicative of similar ion channel activity. Next, we characterized the viral protein using a p7-based trans-complementation approach. A similar subcellular localization pattern at the ER membrane was observed, although production of infectious particles was likely hindered by genetic incompatibilities with HCV proteins. To further characterize these cross-species constraints, chimeric viruses were constructed by substituting different regions of HCV p7 with NPHV p7. The N terminus and transmembrane domains were nonexchangeable and therefore constitute a cross-species barrier in hepaciviral assembly. In contrast, the basic loop and the C terminus of NPHV p7 were readily exchangeable, allowing production of infectious trans-complemented viral particles. In conclusion, comparison of NPHV and HCV p7 revealed structural and functional homology of these proteins, including liposome permeability, and broadly acting determinants that modulate hepaciviral virion assembly and contribute to the host-species barrier were identified. IMPORTANCE: The recent discovery of new relatives of hepatitis C virus (HCV) enables for the first time the study of cross-species determinants shaping hepaciviral pathogenesis. Nonprimate hepacivirus (NPHV) was described to infect horses and represents so far the closest homolog of HCV. Both viruses encode the same viral proteins; however, NPHV protein functions remain poorly understood. In this study, we aimed to dissect NPHV p7 on a structural and functional level. By using various NMR structures of HCV p7 as templates, three-dimensional homology models for NPHV p7 were generated, highlighting conserved residues that are important for ion channel function. A p7-based trans-complementation approach and the construction of NPHV/HCV p7 chimeric viruses showed that the N terminus and transmembrane domains were nonexchangeable. In contrast, the basic loop and the C terminus of NPHV p7 were readily exchangeable, allowing production of infectious viral particles. These results identify species-specific constraints as well as exchangeable determinants in hepaciviral assembly.

Vertical transmission of hepatitis C virus-like non-primate hepacivirus in horses.

Non-primate hepacivirus (NPHV), a recently discovered hepatotropic virus infecting horses, is phylogenetically the closest known homologue of hepatitis C virus (HCV). The main route for acquiring HCV infection in childhood is vertical transmission. However, nothing is known about the natural mode of transmission for NPHV. To investigate the possibility of vertically transmitted NPHV infection in horses, 20 Thoroughbred broodmares and their foals were monitored during foaling season 2015 until 6 months post-partum. Prepartal serum was taken from the mares, and during foaling umbilical cord blood and colostrum samples were collected. Postnatal serum samples were taken from the foals after delivery. In addition, serum was taken at 3 and 6 months after foaling from all mares and foals. Samples were analysed for the presence of NPHV RNA by quantitative real-time PCR and for the presence of anti-NPHV NS3 antibodies by luciferase immunoprecipitation system. Identified NPHV isolates were sequenced and phylogenetic analysis of the viral glycoproteins was used to track the course of naturally occurring infections and the circulation of distinct isolates within the herd. At parturition, 16 mares were seropositive, including four viraemic mares. Vertical transmission occurred in one of these four mare-foal pairs. Interestingly, NPHV isolates of newly infected foals and mares after 3 and 6 months cluster in their respective pasture herds suggesting another horizontal route of transmission.

Protein Counting in Single Cancer Cells.

The cell is the basic unit of biology and protein expression drives cellular function. Tracking protein expression in single cells enables the study of cellular pathways and behavior but requires methodologies sensitive enough to detect low numbers of protein molecules with a wide dynamic range to distinguish unique cells and quantify population distributions. This study presents an ultrasensitive and automated approach for quantifying phenotypic responses with single cell resolution using single molecule array (SiMoA) technology. We demonstrate how prostate specific antigen (PSA) expression varies over several orders of magnitude between single prostate cancer cells and how PSA expression shifts with genetic drift. Single cell SiMoA introduces a straightforward process that is capable of detecting both high and low protein expression levels. This technique could be useful for understanding fundamental biology and may eventually enable both earlier disease detection and targeted therapy.

Clinical course of infection and viral tissue tropism of hepatitis C virus-like nonprimate hepaciviruses in horses.

UNLABELLED: Hepatitis C virus (HCV) has a very narrow species and tissue tropism and efficiently replicates only in humans and the chimpanzee. Recently, several studies identified close relatives to HCV in different animal species. Among these novel viruses, the nonprimate hepaciviruses (NPHV) that infect horses are the closest relatives of HCV described to date. In this study, we analyzed the NPHV prevalence in northern Germany and characterized the clinical course of infection and viral tissue tropism to explore the relevance of HCV-related horse viruses as a model for HCV infection. We found that approximately 31.4% of 433 horses were seropositive for antibodies (Abs) against NPHV and approximately 2.5% carried viral RNA. Liver function analyses revealed no indication for hepatic impairment in 7 of 11 horses. However, serum gamma-glutamyl transferase (GGT) concentrations were mildly elevated in 3 horses, and 1 horse displayed even highly elevated GGT levels. Furthermore, we observed that NPHV infection could be cleared in individual horses with a simultaneous emergence of nonstructural (NS)3-specific Abs and transient elevation of serum levels of liver-specific enzymes indicative for a hepatic inflammation. In other individual horses, chronic infections could be observed with the copresence of viral RNA and NS3-specific Abs for over 6 months. For the determination of viral tissue tropism, we analyzed different organs and tissues of 1 NPHV-positive horse using quantitative real-time polymerase chain reaction and fluorescent in situ hydridization and detected NPHV RNA mainly in the liver and at lower amounts in other organs. CONCLUSION: Similar to HCV infections in humans, this work demonstrates acute and chronic stages of NPHV infection in horses with viral RNA detectable predominantly within the liver.

Acute and chronic infections with nonprimate hepacivirus in young horses.

The recently discovered nonprimate hepacivirus (NPHV) naturally infects horses and is the closest known homolog of hepatitis C virus to date. Within a follow-up study acute field infections were monitored in four young Thoroughbred horses until the ages of 12-13 months. Serum samples were analyzed for the presence of NPHV RNA and anti-NPHV NS3 antibodies and liver specific parameters were evaluated. The four young horses were not able to clear infection, but remained chronically infected for the entire monitored time period despite the presence of NPHV specific antibodies.

Assessment of cross-species transmission of hepatitis C virus-related non-primate hepacivirus in a population of humans at high risk of exposure.

The recent discovery of hepatitis C virus (HCV)-related viruses in different animal species has raised new speculations regarding the origin of HCV and the possibility of a zoonotic source responsible for the endemic HCV transmission. As a consequence, these new findings prompt questions regarding the potential for cross-species transmissions of hepaciviruses. The closest relatives to HCV discovered to date are the non-primate hepaciviruses (NPHVs), which have been described to infect horses. To evaluate the risk of a potential zoonotic transmission, we analysed NPHV RNA and antibodies in humans with occupational exposure to horses in comparison with a low-risk group. Both groups were negative for NPHV RNA, even though low seroreactivities against various NPHV antigens could be detected irrespective of the group. In conclusion, we did not observe evidence of NPHV transmission between horses and humans.

A wheat ABC transporter contributes to both grain formation and mycotoxin tolerance.

The mycotoxin deoxynivalenol (DON) acts as a disease virulence factor for Fusarium fungi, and tolerance of DON enhances wheat resistance to Fusarium head blight (FHB) disease. Two variants of an ATP-binding cassette (ABC) family C transporter gene were cloned from DON-treated wheat mRNA, namely TaABCC3.1 and TaABCC3.2. These represent two of three putative genes identified on chromosomes 3A, 3B, and 3D of the wheat genome sequence. Variant TaABCC3.1 represents the DON-responsive transcript previously associated with DON resistance in wheat. PCR-based mapping and in silico sequence analyses located TaABCC3.1 to the short arm of wheat chromosome 3B (not within the FHB resistance quantitative trait locus Fhb1). In silico analyses of microarray data indicated that TaABCC3 genes are expressed in reproductive tissue and roots, and in response to the DON producer Fusarium graminearum. Gene expression studies showed that TaABCC3.1 is activated as part of the early host response to DON and in response to the FHB defence hormone jasmonic acid. Virus-induced gene silencing (VIGS) confirmed that TaABCC3 genes contributed to DON tolerance. VIGS was performed using two independent viral construct applications: one specifically targeted TaABCC3.1 for silencing, while the other targeted this gene and the chromosome 3A homeologue. In both instances, VIGS resulted in more toxin-induced discoloration of spikelets, compared with the DON effects in non-silenced spikelets at 14 d after toxin treatment (≥2.2-fold increase, P<0.05). Silencing by both VIGS constructs enhanced head ripening, and especially so in DON-treated heads. VIGS of TaABCC3 genes also reduced the grain number by more than 28% (P<0.05), both with and without DON treatment, and the effects were greater for the construct that targeted the two homeologues. Hence, DON-responsive TaABCC3 genes warrant further study to determine their potential as disease resistance breeding targets and their function in grain formation and ripening.

Evidence for the interaction of endophilin a3 with endogenous Kca2.3 channels in PC12 cells.

BACKGROUND/AIMS: Small-conductance calcium-activated (SK) channels play an important role by controlling the after-hyperpolarization of excitable cells. The level of expression and density of these channels is an essential factor for controlling different cellular functions. Several studies showed a co-localization of K(Ca)2.3 channels and Endophilin A3 in different tissues. Endophilin A3 belongs to a family of BAR- and SH3 domain containing proteins that bind to dynamin and are involved in the process of vesicle scission in clathrin-mediated endocytosis. METHODS: Using the yeast two-hybrid system and the GST pull down assay we demonstrated that Endophilin A3 interacts with the N-terminal part of K(Ca)2.3 channels. In addition, we studied the impact of this interaction on channel activity by patch clamp measurements in PC12 cells expressing endogenous K(Ca)2.3 channels. K(Ca)2.3 currents were activated by using pipette solutions containing 1 µM free Ca(2+). RESULTS: Whole-cell measurements of PC12 cells transfected with Endophilin A3 showed a reduction of KCa2.3 specific Cs(+) currents indicating that the interaction of Endophilin A3 with K(Ca)2.3 channels also occurs in mammalian cells and that this interaction has functional consequences for current flowing through K(Ca)2.3 channels. Since K(Ca)2.3 specific currents could be increased in PC12 cells transfected with Endophilin A3 with DC-EBIO (30 µM), a known SK-channel activator, these data also implicate that Endophilin A3 did not significantly remove K(Ca)2.3 channels from the membrane but changed the sensitivity of the channels to Ca(2+) which could be overcome by DC-EBIO. CONCLUSION: This interaction seems to be important for the function of K(Ca)2.3 channels and might therefore play a significant role in situations where channel activation is pivotal for cellular function.

Sexual structures and recombination of the wheat rust fungus Puccinia striiformis on Berberis vulgaris.

An isolate of the basidiomycete Puccinia striiformis, which causes yellow (stripe) rust on wheat, was selfed on the newly discovered alternate host, Berberis vulgaris. This allowed a study of the segregation of molecular markers and virulence in the progeny isolates, and of the development of fungal sexual structures and spore forms. Pycnia and aecia were obtained after inoculation of B. vulgaris with basidiospores resulting from germinating teliospores from infected wheat leaves. Subsequent inoculation of wheat with aeciospores from bulked aecia resulted in 16 progeny isolates of the S1 generation. Genotyping with 42 simple sequence repeat (SSR) markers confirmed a parental origin of progeny isolates. Of the 42 analyzed loci, 15 were heterozygous in the parental isolate and 14 revealed segregation in the progenies. This resulted in 11 new multilocus genotypes (MLGs), which confirmed segregation following sexual reproduction. Additionally, parental and progeny isolates were phenotyped using a genetic stock of wheat genotypes representing 21 resistance genes. All S1 progeny isolates had virulence for 14 out of 15 loci where the parental isolate was virulent. This was consistent with the hypothesis that virulence in plant pathogens is often recessive to avirulence, i.e., only expressed in a homozygous state. Furthermore, no segregation was observed for five out of six loci, for which the parental isolate had an avirulent phenotype. The results for one of the two segregating virulence/avirulence loci suggested that the parental isolate was heterozygous with Avr alleles resulting in different but clearly avirulent phenotypes. The other locus indicated that additional genes modifying the phenotypic expression of avirulence were involved.

Counting the number of magnesium ions bound to the surface-immobilized thymine oligonucleotides that comprise spherical nucleic acids.

Label-free studies carried out under aqueous phase conditions quantify the number of Mg(2+) ions binding to surface-immobilized T40 sequences, the subsequent reordering of DNA on the surface, and the consequences of Mg(2+) binding for DNA-DNA interactions. Second harmonic generation measurements indicate that, within error, 18-20 Mg(2+) ions are bound to the T40 strand at saturation and that the metal-DNA interaction is associated with a near 30% length contraction of the strand. Structural reordering, evaluated using vibrational sum frequency generation, atomic force microscopy, and dynamic light scattering, is attributed to increased charge screening as the Mg(2+) ions bind to the negatively charged DNA, reducing repulsive Coulomb forces between nucleotides and allowing the DNA single strands to collapse or coil upon themselves. The impact of Mg(2+) binding on DNA hybridization and duplex stability is assessed with spherical nucleic acid (SNA) gold nanoparticle conjugates in order to determine an optimal working range of Mg(2+) concentrations for DNA-DNA interactions in the absence of NaCl. The findings are consistent with a charge titration effect in which, in the absence of NaCl, (1) hybridization does not occur at room temperature if an average of 17.5 or less Mg(2+) ions are bound per T40 strand, which is not reached until the bulk Mg(2+) concentration approaches 0.5 mM; (2) hybridization proceeds, albeit with low duplex stability having an average Tm of 31(3)°C, if an average of 17.5-18.0 Mg(2+) ions are bound; and (3) highly stable duplexes having a Tm of 64(2)°C form if 18.5-19.0 Mg(2+) ions are bound, corresponding to saturation of the T40 strand.

Herpesviruses mimic zygotic genome activation to promote viral replication.

DUX4 is a germline transcription factor and a master regulator of zygotic genome activation. During early embryogenesis, DUX4 is crucial for maternal to zygotic transition at the 2-8-cell stage in order to overcome silencing of genes and enable transcription from the zygotic genome. In adult somatic cells, DUX4 expression is silenced and its activation in adult muscle cells causes the genetic disorder Facioscapulohumeral Muscular Dystrophy (FSHD). Here we show that herpesviruses from alpha-, beta- and gamma-herpesvirus subfamilies as well as papillomaviruses actively induce DUX4 expression to promote viral transcription and replication. We demonstrate that HSV-1 immediate early proteins directly induce expression of DUX4 and its target genes including endogenous retroelements, which mimics zygotic genome activation. We further show that DUX4 directly binds to the viral genome and promotes viral transcription. DUX4 is functionally required for herpesvirus infection, since genetic depletion of DUX4 by CRISPR/Cas9 abrogates viral replication. Our results show that herpesviruses induce DUX4 expression and its downstream germline-specific genes and retroelements, thus mimicking an early embryonic-like transcriptional program that prevents epigenetic silencing of the viral genome and facilitates herpesviral gene expression.

In-situ probe of gate dielectric-semiconductor interfacial order in organic transistors: origin and control of large performance sensitivities.

Organic thin film transistor (OTFT) performance is highly materials interface-dependent, and dramatic performance enhancements can be achieved by properly modifying the semiconductor/gate dielectric interface. However, the origin of these effects is not well understood, as this is a classic "buried interface" problem that has traditionally been difficult to address. Here we address the question of how n-octadecylsilane (OTS)-derived self-assembled monolayers (SAMs) on Si/SiO(2) gate dielectrics affect the OTFT performance of the archetypical small-molecule p-type semiconductors P-BTDT (phenylbenzo[d,d]thieno[3,2-b;4,5-b]dithiophene) and pentacene using combined in situ sum frequency generation spectroscopy, atomic force microscopy, and grazing incidence and reflectance X-ray scattering. The molecular order and orientation of the OTFT components at the dielectric/semiconductor interface is probed as a function of SAM growth mode in order to understand how this impacts the overlying semiconductor growth mode, packing, crystallinity, and carrier mobility, and hence, transistor performance. This understanding, using a new, humidity-specific growth procedure, leads to a reproducible, scalable process for highly ordered OTS SAMs, which in turn nucleates highly ordered p-type semiconductor film growth, and optimizes OTFT performance. Surprisingly, the combined data reveal that while SAM molecular order dramatically impacts semiconductor crystalline domain size and carrier mobility, it does not significantly influence the local orientation of the overlying organic semiconductor molecules.

Phenylacetylene one-dimensional nanostructures on the Si(100)-2 x 1:H surface.

Using ultrahigh vacuum (UHV) scanning tunneling microscopy (STM), many olefins have been shown to self-assemble on the hydrogen-passivated Si(100)-2 x 1 surface into one-dimensional nanostructures. This paper demonstrates that similar one-dimensional nanostructures can also be realized using alkynes. In particular, UHV STM, sum frequency generation (SFG), and density functional theory (DFT) are employed to study the growth mechanism and binding configuration of phenylacetylene (PA) one-dimensional nanostructures on the Si(100)-2 x 1:H surface. Molecular-resolution UHV STM images reveal the binding position and spacing of PA with respect to the underlying silicon dimer rows. Furthermore, UHV STM characterization of heteromolecular one-dimensional nanostructures of styrene and PA shows distinct electronic contrast between the two molecules, which is confirmed using simulated STM images derived from DFT and provides insight into the nature of PA binding to silicon. Additional evidence from SFG measurements corroborates the conclusion that the terminal carbon atoms of PA retain pi-conjugation following reaction to the Si(100)-2 x 1:H surface.

Action and reaction of host and pathogen during Fusarium head blight disease.

The Fusarium species Fusarium graminearum and Fusarium culmorum, which are responsible for Fusarium head blight (FHB) disease, reduce world-wide cereal crop yield and, as a consequence of their mycotoxin production in cereal grain, impact on both human and animal health. Their study is greatly promoted by the availability of the genomic sequence of F. graminearum and transcriptomic resources for both F. graminearum and its cereal hosts. Functional genomic, proteomic and metabolomic studies, in combination with targeted mutagenesis or transgenic studies, are unravelling the complex mechanisms involved in Fusarium infection, penetration and colonization of host tissues, and host avoidance thereof. This review illuminates and integrates emerging knowledge regarding the molecular crosstalk between Fusarium and its small-grain cereal hosts. An understanding of the complexity of the host-pathogen interactions will be instrumental in designing new efficient strategies for the control of FHB disease.

Aesthetically pleasant umbilicoplasty.

The umbilicus is an important aesthetic feature of the abdomen and thus calls for an optimized reinsertation technique. Localization and characteristics of the umbilicus were assessed in 137 adults. In addition, age, height, weight, pregnancy, and gender were recorded. Each participant reviewed his own photographs while the authors reviewed all of them. The categorization included a rating and an evaluation of the silhouette. A vertical-configured umbilicus was the most frequently observed. Nevertheless, the score for oval shape was superior. Following a pregnancy, the navel became shorter and wider. Furthermore, the distances measured between the fixed bony points were larger in males and as BMI increased. The height of a person had no impact on the position or height of the umbilicus. An oval-shaped umbilicus that is positioned at 2/3 of the distance from the pubis to the xiphisternum may lead to the most aesthetic results. Thus, the goal in umbilicoplasty is to obtain this configuration.