LacZ gene

Another method is explored with gene expression-based biosensors [19] for Cd measurement. A Cd-responsive promoter from E. coli is fused to a promoterless lacZ gene and monitored with an electrochemical assay of /J-galac-tosidase activity. The expected detection limit is about 0.1 mg L 1 with a response of a few minutes. As for stripping voltammetry, no real tests have been carried out for wastewater. However, biosensors can be considered as a promising technique for wastewater monitoring. 

Bacteria containing the pUC8 plasmid with a gene inserted into the LacZ gene grown on medium containing X-gal are blue in colour BECAUSE... 

PI Many studies have shown that not only Cr but also CD cause damage inside the cells. In this work, three CD compounds were examined for their impact on genotoxicity and cell proliferation in vitro. Chromium chloride added to E. coli strains in the Pro-Tox (C) test system induced lacZ gene transcription from several stress promoters. (Adapted from Plaper et al., 2002)... 

J.X. Yu, P. Otten, Z. Ma, W. Cui, L. Liu, R.P. Mason, A novel NMR platform for detecting gene transfection Synthesis and evaluation of fluorinated phenyl - -Galactosides with potential application for assessing LacZ gene expression, Bioconjug. Chem. 15 (2004) 1334-1341. 

A. Kruger, V. Schirrmacher, R. Khokha, The bacterial lacZ gene An important tool for metastasis research and evaluation if new cancer therapies. Cancer Metastasis Rev. 17 (1999) 285-294. 

J.X. Yu, R.P. Mason, Synthesis and characterization of novel lacZ gene reporter molecules Detection of b-galactosidase activity using F NMR of polyglycosylated fluorinated vitamin B6, J. Med. Chem. 49 (2006) 1991-1999. 

L. Liu, V.D. Kodibagkar, J.-X. Yu, R.P. Mason, F-NMR detection of lacZ gene expression via the enzymic hydrolysis of 2-fluoro-4-nitrophenyl -o-galactopyranoside in vivo in PC3 prostate tumor xenografts in the mouse, Faseb J. 21(2007) 2014-2019. 

In another study, AAV-mediated delivery of the lacZ gene by direct injection to brain tumors which were induced from human glioma cells in nude mice showed that 30% to 40% of the cells along the needle track expressed b-galactosidase subsequent delivery of the HS V-tk/IL-2 genes to these tumors with AAV and administration of GCV to the animals for 6 days resulted in a 35-fold reduction in the mean volume of tumors compared with controls by a significant contribution from the bystander effect (72). 

Table 2.2. Effects of PCR condi tions on mu tation types and frequencies using a 27O-bp fragment of die lacZ gene as a template. Mean values per sequenced clone are given. The mutadon rate (in percent per posidon and PCR) includes all mutadon types.

Pakkanen, T.M., Laitinen, M., Hippelainen, M., Hiltunen, M.O., Alhava, E. and Yla-Herttuala, S. (2000) Periadventitial lacZ gene transfer to pig carotid arteries using a biodegradable collagen collar or a wrap of collagen sheet with adenoviruses and plasmid-liposome complexes. J. Gene Med. 2, 52-60. 

Ligated plasmids should be checked for insertion of the desired fragment instead of just religation, most conveniently by blue-white screening. In vectors with the lacZ gene sequence, insertion at any restriction site of the MCS results in disruption of that sequence so that no /i-galactosidase is expressed and the synthetic X-gal substrate cannot form blue colonies. 

---