Anti-tumoral,anti-angiogenic and anti-metastatic efficacy of a tetravalent bispecific antibody (TAvi6) targeting VEGF-A and angiopoietin-2

Vascular endothelial growth factor (VEGF)-A blockade has been validated clinically as a treatment for human cancers. Angiopoietin-2 (Ang-2) is a key regulator of blood vessel remodeling and maturation. In tumors, Ang-2 is up-regulated and an unfavorable prognostic factor. Recent data demonstrated that Ang-2 inhibition mediates anti-tumoral effects. We generated a tetravalent bispecific antibody (Ang-2-VEGF-TAvi6) targeting VEGF-A with 2 arms based on bevacizumab (Avastin®), and targeting Ang-2 with 2 arms based on a novel anti-Ang-2 antibody (LC06). The two Ang-2-targeting single-chain variable fragments are disulfide-stabilized and fused to the C-terminus of the heavy chain of bevacizumab. Treatment with Ang-2-VEGF-A-TAvi6 led to a complete abrogation of angiogenesis in the cornea micropocket assay. Metastatic spread and tumor growth of subcutaneous, orthotopic and anti-VEGF-A resistant tumors were also efficiently inhibited. These data further establish Ang-2-VEGF bispecific antibodies as a promising anti-angiogenic, anti-metastatic and anti-tumor agent for the treatment of cancer.     

Insights from the reconstitution of the divergent outer kinetochore of Drosophila melanogaster

Accurate chromosome segregation during mitosis and meiosis is crucial for cellular and organismal viability. Kinetochores connect chromosomes with spindle microtubules and are essential for chromosome segregation. These large protein scaffolds emerge from the centromere, a specialized region of the chromosome enriched with the histone H3 variant CENP-A. In most eukaryotes, the kinetochore core consists of the centromere-proximal constitutive centromere-associated network (CCAN), which binds CENP-A and contains 16 subunits, and of the centromere-distal Knl1 complex, Mis12 complex, Ndc80 complex (KMN) network, which binds microtubules and contains 10 subunits. In the fruitfly, Drosophila melanogaster, the kinetochore underwent remarkable simplifications. All CCAN subunits, with the exception of centromeric protein C (CENP-C), and two KMN subunits, Dsn1 and Zwint, cannot be identified in this organism. In addition, two paralogues of the KMN subunit Nnf1 (Nnf1a and Nnf1b) are present. Finally, the Spc105R subunit, homologous to human Knl1/CASC5, underwent considerable sequence changes in comparison with other organisms. We combined biochemical reconstitution with biophysical and structural methods to investigate how these changes reflect on the organization of the Drosophila KMN network. We demonstrate that the Nnf1a and Nnf1b paralogues are subunits of distinct complexes, both of which interact directly with Spc105R and with CENP-C, for the latter of which we identify a binding site on the Mis12 subunit. Our studies shed light on the structural and functional organization of a highly divergent kinetochore particle.     

On the Evolutionary History of Uleiella chilensis,a Smut Fungus Parasite of Araucaria araucana in South America: Uleiellales ord. nov. in Ustilaginomycetes

The evolutionary history, divergence times and phylogenetic relationships of Uleiella chilensis (Ustilaginomycotina, smut fungi) associated with Araucaria araucana were analysed. DNA sequences from multiple gene regions and morphology were analysed and compared to other members of the Basidiomycota to determine the phylogenetic placement of smut fungi on gymnosperms. Divergence time estimates indicate that the majority of smut fungal orders diversified during the Triassic–Jurassic period. However, the origin and relationships of several orders remain uncertain. The most recent common ancestor between Uleiella chilensis and Violaceomyces palustris has been dated to the Lower Cretaceous. Comparisons of divergence time estimates between smut fungi and host plants lead to the hypothesis that the early Ustilaginomycotina had a saprobic lifestyle. As there are only two extant species of Araucaria in South America, each hosting a unique Uleiella species, we suggest that either coevolution or a host shift followed by allopatric speciation are the most likely explanations for the current geographic restriction of Uleiella and its low diversity. Phylogenetic and age estimation analyses, ecology, the unusual life-cycle and the peculiar combination of septal and haustorial characteristics support Uleiella chilensis as a distinct lineage among the Ustilaginomycotina. Here, we describe a new ustilaginomycetous order, the Uleiellales to accommodate Uleiella. Within the Ustilaginomycetes, Uleiellales are sister taxon to the Violaceomycetales.     

The evolutionary and morphological history of the parasphenoid bone in vertebrates

The parasphenoid is located in the cranium of many vertebrates. When present, it is always an unpaired, dermal bone. While most basal vertebrates have a parasphenoid, most placental mammals lack this element and have an unpaired, dermal vomer in a similar position (i.e. associated with the same bones) and with a similar function. As such, the parasphenoid and the vomer were considered homologous by some early twentieth century researchers. However, others questioned this homology based on comparisons between mammals and reptiles. Here we investigate the parasphenoid bone across the major vertebrate lineages (amphibians, reptiles, mammals and teleosts) including both developmental and evolutionary aspects, which until now have not been considered together. We find that within all the major vertebrate lineages there are organisms that possess a parasphenoid and a vomer, while the parasphenoid is absent within caecilians and most placental mammals. Based on our assessment and Patterson's conjunction tests, we conclude that the non‐mammalian parasphenoid and the vomer in mammals cannot be considered homologous. Additionally, the parasphenoid is likely homologous between sarcopterygian and actinopterygian lineages. This research attempts to resolve the issue of the parasphenoid homology and highlights where gaps in our knowledge are still present.     

Impact of food processing and detoxification treatments on mycotoxin contamination

Mycotoxins are fungal metabolites commonly occurring in food, which pose a health risk to the consumer. Maximum levels for major mycotoxins allowed in food have been established worldwide. Good agricultural practices, plant disease management, and adequate storage conditions limit mycotoxin levels in the food chain yet do not eliminate mycotoxins completely. Food processing can further reduce mycotoxin levels by physical removal and decontamination by chemical or enzymatic transformation of mycotoxins into less toxic products. Physical removal of mycotoxins is very efficient: manual sorting of grains, nuts, and fruits by farmers as well as automatic sorting by the industry significantly lowers the mean mycotoxin content. Further processing such as milling, steeping, and extrusion can also reduce mycotoxin content. Mycotoxins can be detoxified chemically by reacting with food components and technical aids; these reactions are facilitated by high temperature and alkaline or acidic conditions. Detoxification of mycotoxins can also be achieved enzymatically. Some enzymes able to transform mycotoxins naturally occur in food commodities or are produced during fermentation but more efficient detoxification can be achieved by deliberate introduction of purified enzymes. We recommend integrating evaluation of processing technologies for their impact on mycotoxins into risk management. Processing steps proven to mitigate mycotoxin contamination should be used whenever necessary. Development of detoxification technologies for high-risk commodities should be a priority for research. While physical techniques currently offer the most efficient post-harvest reduction of mycotoxin content in food, biotechnology possesses the largest potential for future developments.     

High diversity of thermophilic cyanobacteria in Rupite hot spring identified by microscopy,cultivation, single-cell PCR and amplicon sequencing

Extremophiles - Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S...     

A mutation of keratin 18 within the coil 1A consensus motif causes widespread keratin aggregation but cell type-restricted lethality in mice

Mutations in genes encoding epidermal keratins cause skin disorders, while those in internal epithelial keratins, such as K8 and K18, are risk factors for liver diseases. The effect of dominant mutations in K8 or K18 during embryonic development and tissue homeostasis has not been examined so far. Here we demonstrate that the dominant mutation hK18 R89C, that is highly similar to hK14 R125C, causing EBS in humans, leads to cell type-specific lethality in mice, depending on the ratio of mutant to endogenous keratins. Mice expressing hK18 R89C in the absence of endogenous K19 and K18 died at mid-gestation from defects in trophoblast giant cells, accompanied by haematomas. A single, endogenous K18 allele rescued embryonic lethality but caused aggregation of keratins in all adult internal epithelia, surprisingly without spontaneous cell fragility. Closer analysis revealed that both filaments and aggregates coexisted in the same cell, depending on the ratio of mutant to endogenous keratins. Our results demonstrate that balanced overexpression of a wild-type keratin rescued the lethal consequences of a dominant-negative mutation. This has important implications for therapy approaches of keratinopathies, suggesting that suppressing the mutant allele is not necessary in vivo.