The Conceptual Development of a Multifunctional Stepladder for Older People and Caregivers.

Stepladders are compact, foldable ladders with flat steps and a platform. Despite all the research and design efforts, there are still limitations in terms of the multifunctionality, usability and simplicity of stepladders and related variants. By combining ideas, features and functions from patent literature, existing products and scientific journals, this study aims to conceptualise a multifunctional stepladder for improved usability. Five concepts are created, which are screened and evaluated against a set of criteria to select the best concept for improved usability, divided into three categories: simplicity, effectiveness and efficiency. The result is a versatile invention that functions as a stepladder, walker, wheelchair and Pilates chair, suitable for older people and caregivers in nursing homes. It allows medical records or supplies to be retrieved from high places without the need for inappropriate aids. The invention can replace wheelchairs and walkers and converts into a Pilates chair to provide a mobile exercise option for older people. The concept offers older people flexibility and independence in terms of mobility and healthcare, while saving space in the nursing home. Further design studies, prototyping and testing are needed before this idea can go into production.

BARP suppresses voltage-gated calcium channel activity and Ca2+-evoked exocytosis.

Voltage-gated calcium channels (VGCCs) are key regulators of cell signaling and Ca(2+)-dependent release of neurotransmitters and hormones. Understanding the mechanisms that inactivate VGCCs to prevent intracellular Ca(2+) overload and govern their specific subcellular localization is of critical importance. We report the identification and functional characterization of VGCC ß-anchoring and -regulatory protein (BARP), a previously uncharacterized integral membrane glycoprotein expressed in neuroendocrine cells and neurons. BARP interacts via two cytosolic domains (I and II) with all Cavß subunit isoforms, affecting their subcellular localization and suppressing VGCC activity. Domain I interacts at the α1 interaction domain-binding pocket in Cavß and interferes with the association between Cavß and Cavα1. In the absence of domain I binding, BARP can form a ternary complex with Cavα1 and Cavß via domain II. BARP does not affect cell surface expression of Cavα1 but inhibits Ca(2+) channel activity at the plasma membrane, resulting in the inhibition of Ca(2+)-evoked exocytosis. Thus, BARP can modulate the localization of Cavß and its association with the Cavα1 subunit to negatively regulate VGCC activity.

RGK small GTP-binding proteins interact with the nucleotide kinase domain of Ca2+-channel beta-subunits via an uncommon effector binding domain.

RGK proteins (Kir/Gem, Rad, Rem, and Rem2) form a small subfamily of the Ras superfamily. Despite a conserved GTP binding core domain, several differences suggest that structure, mechanism of action, and functional regulation differ from Ras. RGK proteins down-regulate voltage-gated calcium channel activity by binding in a GTP-dependent fashion to the Cavbeta subunits. Mutational analysis combined with homology modeling reveal a novel effector binding mechanism distinct from that of other Ras GTPases. In this model the Switch 1 region acts as an allosteric activator that facilitates electrostatic interactions between Arg-196 in Kir/Gem and Asp-194, -270, and -272 in the nucleotide-kinase (NK) domain of Cavbeta3 and wedging Val-223 and His-225 of Kir/Gem into a hydrophobic pocket in the NK domain. Kir/Gem interacts with a surface on the NK domain that is distinct from the groove where the voltage-gated calcium channel Cavalpha1 subunit binds. A complex composed of the RGK protein and the Cavbeta3 and Cav1.2 subunits could be revealed in vivo using coimmunoprecipitation experiments. Intriguingly, docking of the RGK protein to the NK domain of the Cavbeta subunit is reminiscent of the binding of GMP to guanylate kinase.

Genome scale analysis of diffusible signal factor regulon in Xanthomonas campestris pv. campestris: identification of novel cell-cell communication-dependent genes and functions.

The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc) recruits a diffusible signal factor (DSF), which has recently been structurally characterized as cis-11-methyl-2-dodecenoic acid, as a cell-cell communication signal to synchronize virulence gene expression and biofilm dispersal. In this study, we showed that despite the existance of phenotype variations in different Xcc isolates, the DSF-mediated functions were in general conserved. To investigate the genomic profiles of DSF regulation, we designed and conducted oligomicroarray analysis by comparison of the gene expression patterns of wild-type strain XC1 and its DSF-deficient mutant XC1dF, as well as those of XC1dF in the presence or absence of DSF signals. The analyses led to identification of 165 genes, whose expression was significantly influenced by DSF signals. These genes encode proteins and enzymes belonging to at least 12 functional groups. In addition to those previously known DSF-dependent activities such as production of extracellular enzymes and extracellular polysaccharides, microarray analyses also revealed new functions mediated by DSF, such as flagellum synthesis, resistance to toxins and oxidative stress, and aerobic respiration. Phenotype analyses confirmed that DSF signalling contributed to resistance to toxin acriflavin and hydrogen peroxide, and to the survival of bacterial cells at different temperatures. We conclude that DSF cell-cell signalling is not only essential for co-ordinating the expression of virulence genes but also plays a vital role in keeping up the general competence of the pathogen in ecosystems.