Search results for "Transformation"

Depletion of polyubiquitin encoded by the UBI4 gene confers pleiotropic phenotype to Candida albicans cells.

2003

We have studied the roles of polyubiquitin in Candida albicans physiology. Heterologous expression of the C. albicans polyubiquitin (UBI4) gene in a ubi4 Saccharomyces cerevisiae strain suppressed the mutant phenotype (hypersensitivity to heat shock). A heterozygous strain UBI4/Deltaubi4::hisG, obtained following the ura-blaster procedure, was used to construct a conditional mutant using a pCaDis derivative plasmid. By serendipity we isolated the UBI4 conditional mutant as well as a UBI4 mutant containing a non-functional MET3 promoter. Depletion of polyubiquitin conferred pleiotropic effects to mutant cells: (i) a limited increased sensitivity to mild heat shock; (ii) increased formation o…

Towards a more explicit account of the transformation

2018

Salivary inflammatory proteins in patients with oral potentially malignant disorders

2019

Cytokines are a group of small proteins involved in the regulation of infection, immune responses and inflammation. Since altered cytokine responsiveness has been linked to Oral Squamous Cell Carcinoma (OSCC), research to date indicates the possibility of using salivary pro- and anti-inflammatory proteins for screening of oral disorders. OSCC is a multistep neoplasia in which many genetic and epigenetic changes have been correlated to cancerous transformation of oral potentially malignant disorders (OPMD) such as oral leukoplakia, erythroplakia and lichen planus. The goal of the innovative salivary diagnostics is the identification of a single or multiple biomarkers that will serve as a cli…

The influence of automobile exhausts on mutagenicity of soils: contamination with, fractionation, separation, and preliminary identification of mutag…

2000

To test the assumption that automobile exhausts contribute to soil mutagenicity, two soils with low levels of mutagenic activities were exposed to traffic exhausts at a heavily charged junction of German motorways (Autobahnen) for 3, 7, 10, 13, 17, 21, and 26 weeks. Indeed, in the presence of a metabolic activation system from rat liver (S9), an average increase of 8 and 9 (4 and 12) revertants per gram per week was found in Salmonella typhimurium TA 98 (TA 100). In the absence of S9, meaningful measurements were impossible on account of a concurrent dose dependent increase of toxicity. No correlation between the increase of mutagenicity and the contents of polycyclic aromatic hydrocarbons …

Sulfotransferase-mediated activation of mutagens studied using heterologous expression systems

1998

Abstract Sulfation is a common final step in the biotransformation of xenobiotics and is traditionally associated with inactivation. However, the sulfate group is electron-withdrawing and may be cleaved off heterolytically in some molecules leading to electrophilic cations which may form adducts with DNA and other important cellular structures. Since endogenous sulfotransferases do not appear to be expressed in indicator cells of standard mutagenicity tests, rat and human sulfotransferases have been stably expressed in his−Salmonella typhimurium strain TA1538 and Chinese hamster V79 cells. Using these recombinant indicator cells, sulfotransferase-dependent genotoxic activities were detected…

Dual role of epoxide hydratase in both activation and inactivation of benzo(a)pyrene.

1977

The effect of epoxide hydratase upon the mutagenicity of benzo(a)pyrene was investigated using two Salmonella typhimurium strains (TA 1537 and TA 98). These two bacterial strains were found to differ characteristically in their susceptibility to different mutagens biologically produced from benzo(a)pyrene providing a diagnostic tool to investigate which types of mutagenic metabolites were produced in various metabolic situations. The results showed that the pattern of mutagenic metabolites produced by microsomes from methylcholanthrene-treated mice was very different from that produced by microsomes from phenobarbital-treated or untreated mice. However in all cases at least two mutagenic me…

Influence of nitroreductase and O-acetyltransferase on the mutagenicity of substituted nitrobenzothiophenamines in Salmonella typhimurium.

1999

The mutagenic activity of 17 substituted (aryl)(2-nitrobenzo[b]thiophen-3yl)amines has been evaluated in the Ames test with different isogenic strains of Salmonella typhimurium, that varied in their expression of nitroreductase and O-acetyltransferase. Active derivatives induced frameshift mutations in TA98 strain, and differences in the chemical structure resulted in up to 15-fold changes in mutagenic activity. The non-mutagenic compounds are the unsubstituted parent compound and derivatives with para-chloro, para-fluoro, para-diethylamino, meta-bromo and para-dimethylamino groups. They do not show any activity even in strains with higher level of nitroreductase or O-acetyltransferase. The…

Invariant Feature Matching for Image Registration Application Based on New Dissimilarity of Spatial Features

2016

An invariant feature matching method is proposed as a spatially invariant feature matching approach. Deformation effects, such as affine and homography, change the local information within the image and can result in ambiguous local information pertaining to image points. New method based on dissimilarity values, which measures the dissimilarity of the features through the path based on Eigenvector properties, is proposed. Evidence shows that existing matching techniques using similarity metrics--such as normalized cross-correlation, squared sum of intensity differences and correlation coefficient--are insufficient for achieving adequate results under different image deformations. Thus, new…

Threshold Neutral Pion Photoproduction on the Proton

2015

The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it is very sensitive to higher-order corrections of chiral perturbation theory. We perform a fully covariant calculation up to chiral order p^3 and we investigate the effect of the inclusion of the Delta(1232) resonance as an explicit degree of freedom. We show that the convergence improves, leading to a much better agreement with data at a wide range of energies.

Fast narrowing-driven partial evaluation for inductively sequential programs

2005

Narrowing-driven partial evaluation is a powerful technique for the specialization of (first-order) functional and functional logic programs. However, although it gives good results on small programs, it does not scale up well to realistic problems (e.g., interpreter specialization). In this work, we introduce a faster partial evaluation scheme by ensuring the termination of the process offline . For this purpose, we first characterize a class of programs which are quasi-terminating , i.e., the computations performed with needed narrowing—the symbolic computation mechanism of narrowing-driven partial evaluation—only contain finitely many different terms (and, thus, partial evaluation termi…