Recombinant yeast test

Studies investigating hormonal activity revealed the oestrogenic activity of short-chain NPE in a number of test systems using either recombinant yeast, oestrogen-sensitive MCF-7 cells [98] or a rodent uterotrophic assay response. None of these assays have yet been validated as an internationally accepted toxicity test method, although the MCF-7 and uterotrophic assays have been established for a number of years as standard assays for oestrogenic activity. 

To test the stability of the ethanol production capability of recombinant yeast cells, the cells were recovered by low-speed centrifiigation after 7 days and reused for fermentation for up to seven cycles. As shown in Fig. 1, the concentration of ethanol in each consecutive cycle shows no statistical difference (p<0.05) between each repeated mns and ranging from 48 to 58 g/L (day 7) for each fermentation cycle. 

Boldrin PK, Resende FA, Hohne APO, de Camargo MS, Espanha LG, Nogueira CH, et al. Estrogenic and mutagenic activities of Crotalaria pallid measured by recombinant yeast assay and Ames test. BMC Compl Alternative Med 2013 13 216. 

A number of commercially available rotating disk dynamic membrane systems have been tested for different applications. The DMF module (Pall Corp., New York) consists of several disks mounted on the same shaft, such that each can rotate between two annular membranes with maximum rotation speed of 3450 rpm, corresponding to an azimuthal velocity of 20 m/s at the disk tip. Pali s lab-scale system has been tested for protein separation [64] and filtration of recombinant yeast cells [65]. The studies of the application of the rotating disk dynamic membrane indicated that high-shear-enhanced filtration is much less sensitive to the solid concentration. 

Most of the recombinant subunit vaccines tested in the first half of this decade employed gp 120 or gp 160 expressed in yeast, insect or mammalian (mainly CHO) cell lines. Eukaryotic systems facilitate glycosylation of the protein products. Like all subunit vaccines, these stimulate a humoral-based immune response but fail to elicit a strong T-cell response. The failure to elicit a cell-based... 

Recombinant GM-CSF (produced in Escherichia coli, yeast or COS cells) has been tested for its ability to affect haematopoiesis in primates and humans. Because of its relatively short half-life in the circulation, daily administration (usually via intravenous infusion) is required. Administration results in a transient neutropenia, monocytopenia and eosinopenia within 30 min of administration, presumably because of the ability of GM-CSF to stimulate the expression of adhesins and hence increase the numbers of leukocytes adhered to the capillary endothelium in the marginated pool. Additionally, these leukocytes may accumulate in the lungs after GM-CSF administration, which may contribute to the decrease in the observed numbers... 

The use of yeast cells as a eukaryotic complement to the Ames test led to the development of several protocols for the detection of mutation, gene conversion and recombination. The formal introduction of methods [23] followed by much development work from Zimmermarm s laboratory led to large systematic studies [24, 25] and OECD guidelines for the test battery (OECD 480, 481). However the assays are now rarely used, at least in part because of concerns over low sensitivity, thought to reflect limited permeability of the cell wall. 

As shovm in Figure 19.4, the D7 strain of S. cerevisiae is a particularly useful tool because of its ability to assess various genotoxic events such as intergenic and intragenic mitotic recombination as well as point mutagenesis [37, 38[. In a recent paper, we showed that the D7 yeast strain could detect the phototoxicity of most of chemicals used in the validated phototoxicity test 3T3 NRU, except the antibiotics... 

Fig. 2.2.6.1 Ketoses tested as acceptor substrates of recombinant sucrose synthase 1 expressed in yeast.

The ketoses D-tagatose 6 (43% relative activity) and D-ribulose 28 (24% relative activity) were identified as new acceptor substrates they are not accepted by recombinant SuSyl from yeast. However the acceptance for D-xylulose 5 is lost. The most significant changes were observed for the aldoses tested L-arabinose 14, D-xylose 12, and D-lyxose 11 are better substrates than D-fructose, with relative activities of 490%, 300%, and 151%, respectively. In the hexose series L-glucose 29 and L-rhamnose 30 were identified as new acceptor substrates, whereas the acceptance for D-and L-mannose, 16 and 21, was improved (Fig. 2.2.6.5) (Sauerzapfe and Elling, unpublished results). 

Traditionally protein-protein interactions studies have been performed in vitro after isolation and purification of individual proteins. While some in vivo or in situ protein-protein interaction studies can be performed by traditional methods using microinjection of purified proteins into oocytes, technical complexities limit the number of proteins that can be studied. Furthermore, many putative proteins of interest, predicted by genomic analysis, are not characterized and cannot be used in such studies. Some of the limitations posed by traditional methods have been overcome by use of yeast two-hybrid systems. These systems allow studies of many recombinant test proteins... 

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