The Y-procedure: How to extract the chemical transformation rate from reaction-diffusion data with no assumption on the kinetic model

The paper presents a new method to extract the chemical transformation rate from reaction–diffusion data with no assumption on the kinetic model (“kinetic model-free procedure”). It is a new non-steady-state kinetic characterization procedure for heterogeneous catalysts. The mathematical foundation of the Y-procedure is a Laplace-domain analysis of the two inert zones in a TZTR followed by transposition to the Fourier domain. When combined with time discretization and filtering the Y-procedure leads to an efficient practical method for reconstructing the concentration and reaction rate in the active zone. Using the Y-procedure the concentration and reaction rate of a non-steady state catalytic process can be determined without any pre-assumption regarding the type of kinetic dependence. The Y-procedure is the basis for advanced software for non-steady state kinetic data interpretation. The Y-procedure can be used to relate changes in the catalytic reaction rate and kinetic parameters to changes in the surface composition (storage) of a catalyst.

Development of a novel PCR assay for the identification of the black yeast, Exophiala (Wangiella) dermatitidis from adult patients with cystic fibrosis (CF)

Cystic fibrosis (CF) patients may suffer increased morbidity and mortality through colonisation, allergy and invasive infection from fungi. The black yeast, Exophiala dermatitidis (synonym Wangiella dermatitidis) has been found with increasing frequency in sputum specimens of CF patients, with reported isolation rates ranging from 1.1 to 15.7%. At present, no diagnostic PCR exists to aid with the clinical laboratory detection and identification of this organism. A novel species-specific PCR-based assay was developed for the detection of E. dermatitidis, based on employment of rDNA operons and interspacer (ITS) regions between these rDNA operons. Two novel primers, (designated ExdF & ExdR) were designed in silico with the aid of computer-aided alignment software and with the alignment of multiple species of Exophiala, as well as with other commonly described yeasts and filamentous fungi within CF sputum, including Candida. Aspergillus and Scedosporium. An amplicon of approximately 455 by was generated, spanning the partial ITS I region - the complete 5.8S rDNA region - partial ITS2 region, employing ExdF (forward primer [16-mer], 5'-CCG CCT ATT CAG GTC C-3' and ExdR (reverse primer [16-mer], 5'-TCT CTC CCA CTC CCG C-3', was employed and optimised on extracted genomic DNA from a well characterised culture of E. dermatitidis, as well as with high quality genomic DNA template from a further 16 unrelated fungi, including Candida albicans, C. dubliniensis, C. parapsilosis, C. glabrata, Scedosporium apiospermum, Penicillium sp., Aspergillus fumigatus, Aspergillus versicolor, Pichia guilliermondii, Rhodotorula sp., Trichosporon sp., Aureobasidium pullulans, Fusarium sp., Mucor hiemalis, Bionectria ochroleuca, Gibberella pulicaris. Results demonstrated that only DNA from E. dermatitidis gave an amplification product of the expected sire, whilst none of the other fungi were amplifiable. Subsequent employment of this primer pair detected this yeast from mycological cultures from 2/50 (4%) adult CF patients. These two patients were the only patients who were previously shown to have a cultural history of E. dermatitidis from their sputum. E. dermatitidis is a slow-growing fungus, which usually takes up to two weeks to culture in the microbiology laboratory and therefore is slow to detect conventionally, with the risk of bacterial overgrowth from common co-habiting pan- and multiresistant bacterial pathogens from sputum. namely Pseudomonas aeruginosa and Burkholderia cepacia complex organisms, hence this species-specific PCR assay may help detect this organism from CF sputum more specifically and rapidly. Overall, employment of this novel assay nay help in the understanding of the occurrence. aetiology and epidemiology of E. dermatitidis, as an emerging fungal agent in patients with CF. (C) 2008 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Information processing in the transcriptional regulatory network of yeast: Functional robustness

Background: Gene networks are considered to represent various aspects of molecular biological systems meaningfully because they naturally provide a systems perspective of molecular interactions. In this respect, the functional understanding of the transcriptional regulatory network is considered as key to elucidate the functional organization of an organism.

Nutritional status of adult ewes during early and mid-pregnancy. 2. Effects of supplementation with selenised yeast on ewe reproduction and offspring performance to weaning

The objective of this study was to determine the effects of selenium (Se) supplementation of mature ewes in the period from day - 14 to day 90 post mating on Se status, productivity and viability of ewes and their offspring. Multiparous crossbred ewes (n = 82) were randomly assigned to receive a standard dried grass-based diet (control) or dried grass diet supplemented with 1 g of selenised yeast (Selplex (R)), providing 0.5 mg Se per ewe per day. After day 90 post mating, all ewes were offered grass-based diets supplemented with a standard multivitamin and mineral mix, up to lambing. Ewes that were fed additional Se had increased (P 0,05). Supplemented ewes weaned lambs on average 2 kg heavier than control ewes, due to the higher (P

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.

New members of the chiral pool:  -hydroxypiperidine carboxylates from bakers' yeast reductions of the corresponding keto-esters.

. Knight, David W.; Lewis, Neil; Share, Andrew C.; Haigh, David. Chem. Dept., Univ. of Nottingham, Nottingham, UK. Tetrahedron: Asymmetry (1993), 4(4), 625-8. CODEN: TASYE3 ISSN: 0957-4166. Journal written in English. CAN 120:54423 AN 1994:54423 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract Redn. of the keto-piperidinecarboxylates I and II with fermenting bakers' yeast produced the corresponding hydroxy-esters III and IV in good yields with >99% diastereomeric excess and >93% enantiomeric excess in both cases.

 -Hydroxypiperidinecarboxylates: additions to the chiral pool from bakers' yeast reductions of  -ketopiperidinecarboxylates.

Knight, David W.; Lewis, Neil; Share, Andrew C.; Haigh, David. Chemistry Department, University of Nottingham, Nottingham, UK. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1998), (22), 3673-3684. Publisher: Royal Society of Chemistry, CODEN: JCPRB4 ISSN: 0300-922X. Journal written in English. CAN 130:153545 AN 1998:715806 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract Redn. of the piperidine keto esters, e.g., I, using fermenting bakers' yeast provides high yields of the corresponding hydroxy esters, e.g., II, exclusively as the cis-diastereoisomers and with good levels (?80%) of enantiomeric enrichment. The relative stereochemistries of the products were deduced from NMR data while the abs. configurations were detd. by degrdn. to known piperidinemethanol derivs. or, in the case of hydroxy ester III, by homologation to (R)-3-quinuclidinol IV.

Artemisinins act through at least two targets in a yeast model

Artemisinin and related compounds are potent and widely used antimalarial drugs but their biochemical mode of action is not clear. There is strong evidence that ATP-dependent calcium transporters are a key target in the malarial parasite. However, work using Saccharomyces cerevisiae suggests that disruption of mitochondrial function is critical in the cell killing activity of these compounds. Here it is shown that, in the absence of reducing agents, artemisinin and artesunate targeted the S. cerevisiae calcium channels Pmr1p and Pmc1p. Both compounds affected the growth of yeast on fermentable and nonfermentable media. This growth inhibition was not seen in a yeast strain in which the genes encoding both calcium channels were deleted. In the presence of reducing agents, which break the endoperoxide bridge in the drugs, growth inhibition was only observed in nonfermentable media. This inhibition could be partially relieved by the addition of a free radical scavenger. These results suggest that the drugs have two biochemical modes of action - one acting by specific binding to calcium channels and one involving free radical production in the mitochondria.