Evolution of plant ribosome-inactivating proteins

This contribution presents an updated analysis of the evolution of ribosome-inactivating proteins (RIPs) in plants. All evidence suggests that an ancestor of modern seed plants developed the RIP domain at least 300 million years ago. This ancestral RIP domain gave rise to a direct lineage of type 1 RIPs (i.e. primary type 1 RIPs) still present today in many monocots and at least one dicot. In a later stage a plant succeeded in fusing the RIP domain to a duplicated ricin-B domain acquired from a bacterium. The resulting ancestral type 2 RIP gave rise to all modern type 2 RIPs and by domain deletion to different lines of ‘secondary’ type 1 RIPs and ricin-B type lectins. In a more recent past at least three other domain fusions took place in the family Poaceae whereby type AC1 (type 3), type AC2 and type AD chimeric forms were generated

“You just have to shake them awake!” : experiences of tourists with a disability in Malta

Within the rising amount of tourists visiting Malta each year, there has been one type of tourist who has remained unscrutinized by anthropologists and other social scientists, namely persons with a disability. In the spirit of post-colonial and narrative anthropology, the author wants to give a voice to the people under scrutiny and to offer them a forum to express their thoughts, attitudes and emotion. First, the author will look at what barriers and constraints persons with a disability and the persons who accompany them have to cope with when on holiday in Malta. Secondly, he will focus on the interaction between tourists with a disability/ the people who accompany them and other tourists and locals and the perception of this interaction from the viewpoint of the tourists with a disability. From a comparative perspective, he concludes it’s striking how one glance at previous research done on tourists with a disability shows similar experiences, barriers and constraints as the ones reported in this research. In this regard, the experiences documented may be indicative for the situation in Malta. In the end, he advises it is the responsibility of the government and tourism industry to facilitate the whole process of going on holiday.peer-reviewe

Crystal structure of the GalNAc/Gal-specific agglutinin from the phytopathogenic ascomycete Sclerotinia sclerotiorum reveals novel adaptation of a beta-trefoil domain

International audienceA lectin from the phytopathogenic ascomycete Sclerotinia sclerotiorum that shares only weak sequence similarity with characterized fungal lectins has recently been identified. S. sclerotiorum agglutinin (SSA) is a homodimeric protein consisting of two identical subunits of ∼ 17 kDa and displays specificity primarily towards Gal/GalNAc. Glycan array screening indicates that SSA readily interacts with Gal/GalNAc-bearing glycan chains. The crystal structures of SSA in the ligand-free form and in complex with the Gal-β1,3-GalNAc (T-antigen) disaccharide have been determined at 1.6 and 1.97 Å resolution, respectively. SSA adopts a β-trefoil domain as previously identified for other carbohydrate-binding proteins of the ricin B-like lectin superfamily and accommodates terminal non-reducing galactosyl and N-acetylgalactosaminyl glycans. Unlike other structurally related lectins, SSA contains a single carbohydrate-binding site at site α. SSA reveals a novel dimeric assembly markedly dissimilar to those described earlier for ricin-type lectins. The present structure exemplifies the adaptability of the β-trefoil domain in the evolution of fungal lectins

Extensive homologies between lectins from non-leguminous plants

AbstractSequence studies were performed on lectins from two non-leguminous plants: rice and nettle. Extensive homologies were found between these two proteins and wheat germ agglutinin in support of the conservation of lectin sequences among non-leguminous plants. The number and positions of the cysteine residues were particularly well conserved suggesting a similar folding of the polypeptide chains

Technology ready use of single layer graphene as a transparent electrode for hybrid photovoltaic devices

Graphene has been used recently as a replacement for indium tin oxide (ITO) for the transparent electrode of an organic photovoltaic device. Due to its limited supply, ITO is considered as a limiting factor for the commercialization of organic solar cells. We explored the use of large-area graphene grown on copper by chemical vapor deposition (CVD) and then transferred to a glass substrate as an alternative transparent electrode. The transferred film was shown by scanning Raman spectroscopy measurements to consist of >90% single layer graphene. Optical spectroscopy measurements showed that the layer-transferred graphene has an optical absorbance of 1.23% at a wavelength of 532 nm. We fabricated organic hybrid solar cells utilizing this material as an electrode and compared their performance with ITO devices fabricated using the same procedure. We demonstrated power conversion efficiency up to 3.98%, higher than that of the ITO device (3.86%), showing that layer-transferred graphene promises to be a high quality, low-cost, flexible material for transparent electrodes in solar cell technology.Comment: 6 pages, 3 figure

A New Approach to the Synthesis of Conjugated Polymer: Nanocrystal Composites for Heterojunction Optoelectronics

We report a simple one pot process for the preparation of lead sulphide (PbS) nanocrystals in the conjugated polymer MEH-PPV, and we demonstrate electronic coupling between the two components.Comment: 3 pages, 2 figures, accepted Chem. Comm

Ligand-induced perturbations in Urtica dioica agglutinin

AbstractThe binding of the trisaccharide, N,N′,N″-triacetylchitotriose, to Urtica dioica agglutinin (UDA) was investigated using 1H NMR spectroscopy. UDA is a small antiviral plant lectin containing two homologous 43-amino acid domains. Carbohydrate-induced perturbations occur in one domain of UDA at trisaccharide concentrations below equimolar. Residues in the second domain are shifted at higher carbohydrate concentrations. This data confirms the presence of two binding sites of non-identical affinities per UDA monomer. Qualitative analysis of the 2D NOESY spectra indicates that UDA contains two short stretches of antiparallel β-sheet. The 1H resonance assignments for both antiparallel β-sheet sequences have been completed and there is one β-stretch per domain. A number of these β-sheet residues are perturbed in the presence of carbohydrate

Esthetic improvement in the patient with one missing maxillary central incisor restored with porcelain laminate veneers

This article describes esthetic improvement in a patient with a missing maxillary left central incisor. Space analysis of the anterior dentition showed that minor tooth rearrangement was needed. Optimal space distribution for restorations was attained by orthodontic treatment. Through transforming tooth shape with porcelain laminate veneers, the maxillary left lateral incisor was transformed into central incisor and the maxillary left canine into a lateral incisor. The maxillary right central incisor was also restored for esthetic improvement. In a case of changing a tooth shape with porcelain laminate veneers, pre-treatment evaluation, space analysis and diagnostic wax-up are important factors