FERONIA receptor kinase-regulated reactive oxygen species mediate self-incompatibility in Brassica rapa

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PROMISCUITY,SEXUAL SELECTION,AND GENETIC DIVERSITY: A REPLY TO SPURGIN

We recently reported a positive association between female promiscuity and genetic diversity across passerine birds, and launched the hypothesis that female promiscuity acts as a balancing selection, pressure maintaining genetic diversity in populations (Gohli et al. 2013 ). Spurgin ( 2013 ) questions both our analyses and interpretations. While we agree that the hypothesis needs more comprehensive empirical testing, we find his specific points of criticism unjustified. In a more general perspective, we call for a more explicit recognition of female mating preferences as mechanisms of selection in population genetics theory.     

Modification of the kinetic stability of immunoglobulin G by solvent additives

Biophysical properties of antibody-based biopharmaceuticals are a critical part of their release criteria. In this context, finding the appropriate formulation is equally important as optimizing their intrinsic biophysical properties through protein engineering, and both are mutually dependent. Most previous studies have empirically tested the impact of additives on measures of colloidal stability, while mechanistic aspects have usually been limited to only the thermodynamic stability of the protein. Here we emphasize the kinetic impact of additives on the irreversible denaturation steps of immunoglobulins G (IgG) and their antigen-binding fragments (Fabs), as these are the key committed steps preceding aggregation, and thus especially informative in elucidating the molecular parameters of activity loss. We examined the effects of ten additives on the conformational kinetic stability by differential scanning calorimetry (DSC), using a recently developed three-step model containing both reversible and irreversible steps. The data highlight and help to rationalize different effects of the additives on the properties of full-length IgG, analyzed by onset and aggregation temperatures as well as by kinetic parameters derived from our model. Our results further help to explain the observation that stabilizing mutations in the antigen-binding fragment (Fab) significantly affect the kinetic parameters of its thermal denaturation, but not the aggregation properties of the full-length IgGs. We show that the proper analysis of DSC scans for full-length IgGs and their corresponding Fabs not only helps in ranking their stability in different formats and formulations, but provides important mechanistic insights for improving the conformational kinetic stability of IgGs.     

Digestive cells from Mytilus galloprovincialis show a partial regulatory volume decrease following acute hypotonic stress through mechanisms involving inorganic ions

The response of isolated digestive cells of the digestive gland of Mytilus galloprovincialis to hypotonic shock was studied using videometric methods. The isolated cells exposed to a rapid change (from 1100 to 800 mosmol kg^?1) of the bathing solution osmolality swelled but thereafter underwent a regulatory volume decrease (RVD), tending to recover the original size. When the hypotonic stress was applied in the presence of quinine and glibenclamide, known inhibitors of swelling activated ion channels, the cells did not exhibit an RVD response; in addition, they showed a larger increase in size in respect to control cells. These observations suggest that the digestive cells of the digestive gland have the machinery to cope with the hyposmotic shock allowing them to exhibit a small but significant RVD preventing an excessive increase in cell size. The pharmacological treatment of digestive cells during the RVD experiments suggests that cell volume is regulated by K⁺ and Cl^? efflux followed by an obliged water efflux from the cell. The involvement of organic osmolytes such as taurine and betaine seems to be excluded by NMR measurement on digestive cells. Copyright © 2012 John Wiley & Sons, Ltd.