Interactions between the budding yeast IQGAP homologue Iqg1p and its targets revealed by a split-EGFP bimolecular fluorescence complementation assay.

A split-EGFP based bimolecular fluorescence complementation (BiFC) assay has been used to detect interactions between the Saccharomyces cerevisiae cytoskeletal scaffolding protein Iqg1p and three targets: myosin essential light chain (Mlc1p), calmodulin (Cmd1p) and the small GTPase Cdc42p. The format of the BiFC assay used ensures that the proteins are expressed at wild type levels thereby avoiding artefacts due to overexpression. This is the first direct in vivo detection of these interactions; in each case, the complex is localised to discrete regions of the yeast cytoplasm. The labelling with EGFP fragments results in changes in growth kinetics, cell size and budding frequency. This is partly due to the reassembled EGFP locking the complexes into essentially permanent interactions. The consequences of this for Iqg1p interactions and BiFC assays in general are discussed. (c) 2008 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Physicochemical Characterization of Hot Melt Extruded Bicalutamide–Polyvinylpyrrolidone Solid Dispersions

Solid molecular dispersions of bicalutamide (BL) and polyvinylpyrrolidone (PVP) were prepared by hot melt extrusion technology at drug-to-polymer ratios of 1:10, 2:10, and 3:10 (w/w). The solid-state properties of BL, physical mixtures of BL/PVP, and hot melt extrudates were characterized using differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), Raman, and Fourier transform infrared (FTIR) spectroscopy. Drug dissolution studies were subsequently conducted on hot melt extruded solid dispersions and physical mixtures. All hot melt extrudates had a single Tg between theTg of amorphous BL and PVP indicating miscibility of BL with PVP and the formation of solid molecular dispersions. PXRD con?rmed the presence of the amorphous form of BL within the extrudates. Conversely, PXRD patterns recorded for physical mixtures showed sharp bands characteristic of crystalline BL, whereas DSC traces had a distinct endotherm at 1968C corresponding to melting of crystalline BL. Further investigations using DSC con?rmed solid-state plasticization of PVP by amorphous BL and hence antiplasticization of amorphous BL by PVP. Experimentally observed Tg values of physical mixtures were shown to be signi?cantly higher than those calculated using the Gordon–Taylor equation suggesting the formation of strong intermolecular interactions between BL and PVP. FTIR and Raman spectroscopy were used to investigate these interactions and strongly suggested the presence of secondary interaction between PVP and BL within the hot melt extrudates. The drug dissolution properties of hot melt extrudates were enhanced signi?cantly in comparison to crystalline BL and physical mixtures. Moreover, the rate and extent of BL release were highly dependent on the amount of PVP present within the extrudate. Storage of the extrudates con?rmed the stability of amorphous BL for up to 12 months at 208C, 40% RH whereas stability was reduced under highly humid conditions (208C, 65% RH). Interestingly, BL recrystallization after storage under these conditions had no effect on the dissolution properties of the extrudates.

Disjoint mixing operators

Chan and Shapiro showed that each (non-trivial) translation operator acting on the Fréchet space of entire functions endowed with the topology of locally uniform convergence supports a universal function of exponential type zero. We show the existence of d-universal functions of exponential type zero for arbitrary finite tuples of pairwise distinct translation operators. We also show that every separable infinite-dimensional Fréchet space supports an arbitrarily large finite and commuting disjoint mixing collection of operators. When this space is a Banach space, it supports an arbitrarily large finite disjoint mixing collection of C0-semigroups. We also provide an easy proof of the result of Salas that every infinite-dimensional Banach space supports arbitrarily large tuples of dual d-hypercyclic operators, and construct an example of a mixing Hilbert space operator T so that (T,T2) is not d-mixing.

Primary irsi stromal cyst:A report of 17 cases

Objective: To describe clinical characteristics, management, and complications of primary iris stromal cysts. Design: A retrospective review. Results: Seventeen consecutive patients with primary iris stromal cysts were found. Nine (52%) patients were diagnosed under age 10 years (range, 1 day-7 years), and eight (47%) patients were diagnosed after age 10 years (range, 14-71 years). Overall, the cyst appeared unilaterally as a solitary clear translucent mass dissecting the iris stroma in all cases. The children with a primary iris stromal cyst demonstrated a more aggressive course than teenagers or adults. In children, the cyst obstructed the visual axis in eight cases (88%), requiring treatment such as aspiration, cryotherapy, and resection. In seven children, multiple treatments were necessary. Ultimate control of the cyst was achieved in all cases using techniques of needle aspiration (with or without cryotherapy) in three cases and using resection in five cases. Primary iris stromal cysts in teenagers and adults necessitated intervention in only two cases (25%). Conclusion: Primary iris stromal cysts can occur in children, teenagers, and adults. In children, primary stromal iris cysts appear to have a more aggressive clinical course, often requiring several treatments for globe and vision preservation.

Intraspecific variation in nitrogen source utilisation by isolates of the ericoid mycorrhizal fungus Hymenoscyphus Ericae (Read) Korf and Kernan

Variation in the abilities of 35 isolates of the ericoid mycorrhizal fungal endophyte Hymenoscyphus ericae from two field sites to utilise inorganic and organic nitrogen sources in axenic culture has been investigated. While most isolates showed a preference for NH₄/^- as a sole nitrogen source, considerable variation was observed in the abilities of isolates to utilise amino acids and protein (BSA). In particular, large intraspecific variation was observed for glutamine and BSA utilisation, with some isolates thriving on these substrates while others produced little growth. The data suggest that individual isolates of H. ericae may vary considerably in their abilities to supply their host plants with nitrogen from different substrates in soil. (C) 2000 Elsevier Science Ltd.