The use of thaumatin and bovine serum albumin as proteins in model wine solutions in bentonite fining

This study examined the viability of using thaumatin and bovine serum albumin (BSA) as proteins in model wine solutions for bentonite fining studies and compared them with unfined New Zealand sauvignon blanc (SB) wine. Bentonite fining trials were performed on model wine solutions and unfined SB wines (pH range 3.5 to 4.3). Thaumatin was more readily adsorbed onto bentonites of all types than BSA and its adsorption onto bentonite was less affected by the pH of the solution. Specifically, the amount of BSA adsorbed onto bentonite decreased significantly as the pH of the solution approached the isoelectric point (pI) of BSA while thaumatin was adsorbed at that pH due to its higher pI. Changing pH affected protein adsorption of real wine less noticeably than of BSA and thaumatin, and decreasing pH increased protein adsorption in contrast to the model solutions. Neither of the model solutions can fully represent the response of real wine to bentonite fining but they are simple and cost effective to prepare and reacted to changes in bentonite concentration similar to real wine. Thaumatin is potentially a better protein to use in simple model solutions for wine stabilisation studies like filtration where molecular weights are important consideration

Oldest Known Eucalyptus Macrofossils Are from South America

The evolutionary history of Eucalyptus and the eucalypts, the larger clade of seven genera including Eucalyptus that today have a natural distribution almost exclusively in Australasia, is poorly documented from the fossil record. Little physical evidence exists bearing on the ancient geographical distributions or morphologies of plants within the clade. Herein, we introduce fossil material of Eucalyptus from the early Eocene (ca. 51.9 Ma) Laguna del Hunco paleoflora of Chubut Province, Argentina; specimens include multiple leaves, infructescences, and dispersed capsules, several flower buds, and a single flower. Morphological similarities that relate the fossils to extant eucalypts include leaf shape, venation, and epidermal oil glands; infructescence structure; valvate capsulate fruits; and operculate flower buds. The presence of a staminophore scar on the fruits links them to Eucalyptus, and the presence of a transverse scar on the flower buds indicates a relationship to Eucalyptus subgenus Symphyomyrtus. Phylogenetic analyses of morphological data alone and combined with aligned sequence data from a prior study including 16 extant eucalypts, one outgroup, and a terminal representing the fossils indicate that the fossils are nested within Eucalyptus. These are the only illustrated Eucalyptus fossils that are definitively Eocene in age, and the only conclusively identified extant or fossil eucalypts naturally occurring outside of Australasia and adjacent Mindanao. Thus, these fossils indicate that the evolution of the eucalypt group is not constrained to a single region. Moreover, they strengthen the taxonomic connections between the Laguna del Hunco paleoflora and extant subtropical and tropical Australasia, one of the three major ecologic-geographic elements of the Laguna del Hunco paleoflora. The age and affinities of the fossils also indicate that Eucalyptus subgenus Symphyomyrtus is older than previously supposed. Paleoecological data indicate that the Patagonian Eucalyptus dominated volcanically disturbed areas adjacent to standing rainforest surrounding an Eocene caldera lake

Small molecules, big targets: drug discovery faces the protein-protein interaction challenge.

Protein-protein interactions (PPIs) are of pivotal importance in the regulation of biological systems and are consequently implicated in the development of disease states. Recent work has begun to show that, with the right tools, certain classes of PPI can yield to the efforts of medicinal chemists to develop inhibitors, and the first PPI inhibitors have reached clinical development. In this Review, we describe the research leading to these breakthroughs and highlight the existence of groups of structurally related PPIs within the PPI target class. For each of these groups, we use examples of successful discovery efforts to illustrate the research strategies that have proved most useful.JS, DES and ARB thank the Wellcome Trust for funding.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nrd.2016.2

Structure of the complete human TSC:WIPI3 lysosomal recruitment complex

Tuberous sclerosis complex (TSC) turns off cell growth in response to energy stress by inhibiting the master kinase mechanistic target of rapamycin complex (mTORC1). TSC hydrolyzes RAS homolog-mTORC1 binding (RHEB) from its GTP-bound to GDP-bound state, preventing the allosteric activation of mTORC1. Loss-offunction TSC mutations hyperactivate mTORC1 resulting in the common genetic disorder TSC characterized by excess cell growth and tumor formation. Here we overcome a high degree of continuous conformational heterogeneity to determine the 2.9 Å cryo-electron microscopy (cryo-EM) structure of the complete human TSC in complex with the lysosomal recruitment factor WIPI3. TSC forms an elongated 40 nm wing-like structure with a core HEAT-repeat scaffold formed by a TSC2 dimer joined centrally by the juxtaposition of two catalytic domains. The TSC1 coil-coil dimer runs across the TSC2 surface, forming a previously undetected N-terminal TSC1 dimer that clamps onto the core scaffold on a single TSC wing. Structural and biochemical analysis reveals a novel phosphatidylinositol phosphate (PIP)-binding pocket in the TSC1 dimer interface that specifically binds singularly phosphorylated PIPs. WD repeat domain phosphoinositide-interacting-protein-3 (WIPI3) binds to the extreme tip of the complex through a conserved motif in TSC1, providing a second membrane anchor point for TSC lysosomal recruitment. The TSC:WIPI3 complex helps explain how TSC lysosomal recruitment proteins coordinate with endolysosomal phosphoinositide-signaling networks to regulate TSC localization, RHEB hydrolysis, and mTORC1 inhibition. More broadly, the high-resolution structure of the complete human TSC identifies novel mutational hotspots that unravel crucial new mechanisms of TSC dysregulation in disease.</p