Modification of the degree of branching of a beta‐(1,3)‐glucan affects aggregation behavior and activity in an oxidative burst assay

Scleroglucan is a β‐(1,3)‐glucan which is highly branched at the 6‐position with a single glucose residue. Acid hydrolysis of a high molecular weight scleroglucan gave a medium molecular weight, freely soluble material. Linkage analysis by the partially methylated alditol acetate method showed that the solubilized material had 30% branching. When the material was subjected to partial Smith degradations, the percent branching was reduced accordingly to 12% or 17%. After the percent branching was reduced, the average molecular weight of the samples increased considerably, indicating the assembly of higher ordered aggregate structures. An aggregate number distribution analysis was applied to confirm the higher aggregated structures. These aggregated structures gave the material significantly enhanced activity in an in vitro oxidative burst assay compared to the highly branched material. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 665–674, 2015.     

Invertebrate prey availability limits reproductive success but not breeding population size in suburban House Sparrows Passer domesticus

Factors affecting avian demography and abundance in urban landscapes are poorly understood and this hinders attempts to manage urban bird communities. Several recent studies indicate that lack of invertebrate prey in urban landscapes may constrain avian productivity and fitness relative to that in other habitats. House Sparrow Passer domesticus populations have undergone large declines in many European urban centres and inadequate reproductive success linked to invertebrate availability has been postulated as a potential cause of these declines. We conducted a replicated supplementary feeding experiment to test whether the availability of invertebrate prey limits the breeding success and adult abundance (colony size) of House Sparrows in suburban London, where House Sparrow populations declined by 60% during the decade preceding our study. Daily mealworm provision over two successive breeding seasons, sufficient to provide 82% of chick energy requirements of House Sparrow pairs nesting within 50 m of feeders, had a large positive impact on the abundance of recently fledged birds (+62%), but only a small positive impact, limited mainly to small colonies, on the overall abundance of territorial males. Colony growth was only weakly related to fledgling abundance in the previous year and did not appear to be constrained by nest‐site availability. Conservation interventions that enhance invertebrate availability for suburban House Sparrows may increase reproductive success but are unlikely, on their own, to lead to population growth or recovery.     

Comparison of Francisella tularensis genomes reveals evolutionary events associated with the emergence of human pathogenic strains

Background

Francisella tularensis subspecies tularensis and holarctica are pathogenic to humans, whereas the two other subspecies, novicida and mediasiatica, rarely cause disease. To uncover the factors that allow subspecies tularensis and holarctica to be pathogenic to humans, we compared their genome sequences with the genome sequence of Francisella tularensis subspecies novicida U112, which is nonpathogenic to humans.

Results

Comparison of the genomes of human pathogenic Francisella strains with the genome of U112 identifies genes specific to the human pathogenic strains and reveals pseudogenes that previously were unidentified. In addition, this analysis provides a coarse chronology of the evolutionary events that took place during the emergence of the human pathogenic strains. Genomic rearrangements at the level of insertion sequences (IS elements), point mutations, and small indels took place in the human pathogenic strains during and after differentiation from the nonpathogenic strain, resulting in gene inactivation.

Conclusion

The chronology of events suggests a substantial role for genetic drift in the formation of pseudogenes in Francisella genomes. Mutations that occurred early in the evolution, however, might have been fixed in the population either because of evolutionary bottlenecks or because they were pathoadaptive (beneficial in the context of infection). Because the structure of Francisella genomes is similar to that of the genomes of other emerging or highly pathogenic bacteria, this evolutionary scenario may be shared by pathogens from other species.     

WVD2 is a novel microtubule-associated protein in Arabidopsis thaliana

Arabidopsis WAVE-DAMPENED 2 (WVD2) was identified by forward genetics as an activation-tagged allele that causes plant and organ stockiness and inversion of helical root growth handedness on agar surfaces. Plants with high constitutive expression of WVD2 or other members of the WVD2-LIKE (WDL) gene family have stems and roots that are short and thick, have reduced anisotropic cell elongation, are suppressed in a root-waving phenotype, and have inverted handedness of twisting in hypocotyls and roots compared with wild-type. The wvd2-1 mutant shows aberrantly organized cortical microtubules in peripheral root cap cells as well as reduced branching of trichomes, unicellular leaf structures whose development is regulated by microtubule stability. Orthologs of the WVD2/WDL family are found widely throughout the plant kingdom, but are not similar to non-plant proteins with the exception of a C-terminal domain distantly related to the vertebrate microtubule-associated protein TPX2. in vivo, WVD2 and its closest paralog WDL1 are localized to interphase cortical microtubules in leaves, hypocotyls and roots. Recombinant glutathione-S-transferase:WVD2 or maltose binding protein:WVD2 protein bind to and bundle microtubules in vitro. We speculate that a C-terminal domain of TPX2 has been utilised by the WVD2 family for functions critical to the organization of plant microtubules.     

Synthesis and biological evaluation of fenobam analogs as mGlu5 receptor antagonists

Optimization of affinity and microsomal stability led to identification of the potent, metabolically stable fenobam analog 4l. Robust in vivo efficacy of 4l was demonstrated in four different models of anxiety. Additionally, a ligand based pharmacophore alignment of fenobam and MPEP is proposed.     

Mind the sustainability gap

Despite increasing efforts to reach sustainability, key global biophysical indicators such as climate change and biodiversity loss continue to deteriorate rather than improve. Ongoing failure to move towards sustainability calls into question the focus of current research and policy. We recommend two strategies for progress. First, sustainability must be conceptualized as a hierarchy of considerations, with the biophysical limits of the Earth setting the ultimate boundaries within which social and economic goals must be achieved. Second, transdisciplinary research programs must confront key normative questions facing modern consumer societies. The humanities should have a key role in such programs. Assisted by these strategies, ambitious targets that realistically reflect the biophysical limits of the life-support system of the Earth must be set and relentlessly worked towards.     

Effects of saddle height on anaerobic power production in cycling

In competitive cycling, setting the proper saddle height is important for both performance and injury prevention. This is also true for ergometer use in a laboratory. The cycling literature recommends using a 25 to 35 degrees knee angle to set saddle height for injury prevention and recommends using 109% of inseam length for optimal performance. Prior research has demonstrated that these 2 methods do not produce similar saddle heights. The purpose of this study was to determine if there is a difference in performance between these 2 methods. Trained cyclists (n = 9) and noncyclists (n = 18) participated in this study. Anaerobic power production was compared using a 30s Wingate protocol at a saddle height of 109% of inseam and at 25 and 35 degrees knee angles. Saddle height set using 109% of inseam fell outside the recommended 25 to 35 degrees knee angle 63% of the time. There were no significant differences (p > 0.05) for peak power and mean power in either group between saddle heights. The data when using 109% to set saddle height were then divided into those that fell within the recommended 25 to 35 degrees knee angle and those that fell outside. A 25 degrees knee angle produced a significantly higher mean power compared with 109% in those that fell outside the recommended range. An increase in power, at a 25 degrees angle, can be extrapolated to increased performance. There was no difference in performance detected in those individuals who fell within the recommended range. For this reason it is recommended that saddle height for cycles and ergometers be set using a 25 to 35 degrees knee angle for both trained and untrained cyclists for both injury prevention and increased performance.     

Induction of Potent Neutralizing Antibody Responses by a Designed Protein Nanoparticle Vaccine for Respiratory Syncytial Virus

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Chemically defined medium environment for the development of renal stem cells into tubules

The use of stem cells is a valuable therapeutical option for the regeneration of diseased tissues and organs. However, the involved cellular processes are hardly known. To gain detailed information about their development, a new culture technology was developed. Embryonic renal tissue containing stem/progenitor cells was mounted within a perfusion culture container at the interface of an artificial interstitium made of polyester. Using this innovative approach we show that renal tubules develop in chemically defined Iscove's modified Dulbecco's medium without serum addition and without coating by extracellular matrix proteins. The development of tubules depends on the administration of aldosterone, and can be visualized by immunohistochemical labeling. The presented technology makes the exact analysis of developmental steps now possible, and provides a new powerful tool to optimize growth and differentiation of renal stem cells. It may also enable many other kinds of stem cells to steer their development into functional tissues under clearly defined in vitro conditions.