Leaf thionins, a novel class of putative defence factors

Leaf thionins of barley have been identified as a novel class of highly abundant polypeptides with antifungal activity, which are present in walls and vacuoles of barley leaf cells. Similar thionins occur not only in monocotyledonous but also in various dicotyledonous plants. The leaf thionins of barley are encoded by a complex multigene family, which consists of at least 50–100 members per haploid genome. The toxicity of these thionins for plant pathogenic fungi and the fact that their synthesis can also be triggered by pathogens strongly suggest that leaf thionins are involved in the mechanism of plant defence against microbiol infection.     

Directed evolution of a highly active Yersinia mollaretii phytase

Phytase improves as a feed supplement the nutritional quality of phytate-rich diets (e.g., cereal grains, legumes, and oilseeds) by hydrolyzing indigestible phytate (myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate) and increasing abdominal absorption of inorganic phosphates, minerals, and trace elements. Directed phytase evolution was reported for improving industrial relevant properties such as thermostability (pelleting process) or activity. In this study, we report the cloning, characterization, and directed evolution of the Yersinia mollaretii phytase (Ymphytase). Ymphytase has a tetrameric structure with positive cooperativity (Hill coefficient was 2.3) and a specific activity of 1,073?U/mg which is ～10 times higher than widely used fungal phytases. High-throughput prescreening methods using filter papers or 384-well microtiter plates were developed. Precise subsequent screening for thermostable and active phytase variants was performed by combining absorbance and fluorescence-based detection system in 96-well microtiter plates. Directed evolution yielded after mutant library generation (SeSaM method) and two-step screening (in total ～8,400 clones) a phytase variant with ～20% improved thermostability (58°C for 20?min; residual activity wild type ～34%; variant ～53%) and increased melting temperature (1.5°C) with a slight loss of specific activity (993?U/mg).     

The dynamics of food chains under climate change and nutrient enrichment

Warming has profound effects on biological rates such as metabolism, growth, feeding and death of organisms, eventually affecting their ability to survive. Using a nonlinear bioenergetic population-dynamic model that accounts for temperature and body-mass dependencies of biological rates, we analysed the individual and interactive effects of increasing temperature and nutrient enrichment on the dynamics of a three-species food chain. At low temperatures, warming counteracts the destabilizing effects of enrichment by both bottom-up (via the carrying capacity) and top-down (via biological rates) mechanisms. Together with increasing consumer body masses, warming increases the system tolerance to fertilization. Simultaneously, warming increases the risk of starvation for large species in low-fertility systems. This effect can be counteracted by increased fertilization. In combination, therefore, two main drivers of global change and biodiversity loss can have positive and negative effects on food chain stability. Our model incorporates the most recent empirical data and may thus be used as the basis for more complex forecasting models incorporating food-web structure.     

Identification and evaluation of novel synovial tissue biomarkers in rheumatoid arthritis by laser scanning cytometry

Introduction

Suitable biomarkers are essential for therapeutic strategies in personalized medicine in terms of diagnosis as well as of prognosis. With highly specific biomarkers, it is possible, for example, to identify patients with poor prognosis, which enables early intervention and intensive treatment. The aim of this study was to identify and validate biomarkers and possible combinations for a prospective use in immunoscintigraphy, which may improve diagnosis of rheumatoid arthritis (RA) patients with consideration of inflammatory activity in the affected joints. Therefore, we tested several monoclonal antibodies (mAbs) directed against cellular-surface molecules on cells likely to be involved in the pathogenesis of RA.

Methods

Synovial tissue from patients with long-standing RA (accompanied by synovitis with varying states of current activity) and patients with acute non-RA arthritis were stained for surface molecules on different cell types by using fluorochrome-labeled antibodies. Tissue analysis was done by laser scanning cytometry (LSC), and statistical evaluation, by discriminant analysis and ROC analysis.

Results

CD11b, HLA-DR, CD90, and CD64 revealed significant differences between tissues from patients with RA and acute non-RA arthritis. Especially with the expression of CD64, both patient cohorts could be discriminated with high sensitivity and specificity. RA classification was improved by simultaneously investigating the expression of two or three different surface proteins, such as HLA-DR, CD90, and CD29 in the tissue. The simultaneous analysis of CD64 together with CD304 or the combination of CD11b and CD38 was suitable for the identification of RA patients with high current activity in synovitis.

Conclusions

In this study, we showed that LSC is a novel reliable method in biomarker prevalidation in RA. Hence, identified mAbs in situ may allow their potential use in in vivo approaches. Moreover, we proved that biomarker-combination analysis resulted in better discrimination than did single-marker analysis. Combinations of these markers make a novel and reliable panel for the discrimination between RA and acute non-RA arthritis. In addition, further expedient combinations may be novel promising biomarker panels to identify current activity in synovitis in RA.     

Elaborate visual and acoustic signals evolve independently in a large,phenotypically diverse radiation of songbirds

The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the ‘transfer hypothesis’ is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here, we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers.     

A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum

Rhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study, Bradyrhizobium japonicum USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes oxc (for oxalyl-coenzyme A decarboxylase) and frc (for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different B. japonicum host plants. Mixed-inoculation experiments with wild-type and oxc-frc mutant cells revealed that oxalotrophy might be a beneficial trait of B. japonicum at some stage during legume root nodule colonization.     

The nucleoporin Nup358/RanBP2 promotes nuclear import in a cargo- and transport receptor-specific manner

In vertebrates, the nuclear pore complex (NPC), the gate for transport of macromolecules between the nucleus and the cytoplasm, consists of approximately 30 different nucleoporins (Nups). The Nup and SUMO E3-ligase Nup358/RanBP2 are the major components of the cytoplasmic filaments of the NPC. In this study, we perform a structure-function analysis of Nup358 and describe its role in nuclear import of specific proteins. In a screen for nuclear proteins that accumulate in the cytoplasm upon Nup358 depletion, we identified proteins that were able to interact with Nup358 in a receptor-independent manner. These included the importin α/β-cargo DBC-1 (deleted in breast cancer 1) and DMAP-1 (DNA methyltransferase 1 associated protein 1). Strikingly, a short N-terminal fragment of Nup358 was sufficient to promote import of DBC-1, whereas DMAP-1 required a larger portion of Nup358 for stimulated import. Neither the interaction of RanGAP with Nup358 nor its SUMO-E3 ligase activity was required for nuclear import of all tested cargos. Together, Nup358 functions as a cargo- and receptor-specific assembly platform, increasing the efficiency of nuclear import of proteins through various mechanisms.