细胞功能测定

Mammalian paraoxonases (PON1, PON2, PON3) are a unique family of calcium-dependent hydrolases, with enzymatic activities toward a broad range of substrates (lactones, thiolactones, carbonates, esters, phosphotriesters). Although PONs physiological substrates were not y ...

Bacillus stearothermophilus, a thermophilic bacterium isolated from Kuwaiti desert, when incubated with exogenous progesterone for 10 days at 65�C produced two monohydroxylated, two dihydroxy isomers of progesterone and a B-Seco compound. These metabolites were purified by T ...

Physical and biological parameters affecting DNA delivery into oil palm embryogenic calli using the biolistic device are optimized. Five different promoters are also evaluated to identify the most suitable promoter for use in oil palm transformation. Finally, the effectiveness of ...

This chapter describes the need for, as well as the process of, development, manufacture, and the clinical evaluation of a multi-antioxidant formulation. The formulation is in a chewable tablet form, for use in dogs showing clinical signs of cognitive dysfunction syndrome.

In order to develop a more complete understanding of the genes required for resistance to oxidative DNA damage, we devised methods to identify genes that can prevent or repair oxidative DNA damage. These methods use the oxidative mutator phenotype of a repair deficient E. coli strain to measure t ...

Genome-wide screens have proven powerful in associating gene products with certain phenotypes or signal transduction pathways, and thus are valuable tools to ascribe gene function. These genomic screens can be extended to discover genes/proteins that attenuate oxidative stres ...

Cellular systems produce reactive oxygen species during the process of metabolism. Oxidative stress results in the activation or repression of many genes in important signaling pathways. DNA microarrays allow for a high throughput evaluation of the changes in gene expression levels ...

Microarray hybridization allows genome-wide screening of changes in mRNA levels under stress conditions. In Saccharomyces cerevisiae, this approach has demonstrated that responses to heat stress, oxidative stress, nutrient deprivation, and other stress signals are highly o ...

Molecular imaging offers many unique opportunities to study biological processes in intact organisms. Bioluminescence is the emission of light from biochemical reactions that occur within a living organism. Luciferase has been used as a reporter gene in transgenic mice but, until bi ...

Deciphering the differentiation pathway of embryonic stem (ES) cells is a challenging task not only for basic research, but also for clinicians who intend to use ES cells for cell transplantation approaches. We have shown that reactive oxygen species (ROS) play a primordial role in the differe ...

The use of biomarkers to assess exposure and investigate biomedical questions is common in epidemiology. The usefulness of biomarker research, however, is contingent upon the ability to achieve a complete understanding of the role they play within a population. In estimating distribu ...

It is frequently desirable to use normal genetically stable human cells as recipients of exogenous genes. However, normal human cell strains have not often been used because of their finite life-span. Instead, immortal human cell lines have usually been used as genetic recipients. These cell ...

The study of gene expression regulation relies on the introduction of foreign DNA into eukaryotic cells. A wide variety of DNA-transfer procedures have been developed that utilize retroviruses (1), polycations (2), liposomes (3), chromosomes (4), reconstituted viral envelopes (5) and ...

There are many reasons to introduce new genes on recombinant vectors into mammalian cells. For example, in situ studies of the effects of particular gene products on DNA replication (1–3), repair (4–6), recombination (7), or gene expression (7–11) can be performed. Alternatively, vectors that s ...

The production of transgenic laboratory animals has rapidly gained importance as an experimental tool to study the factors that determine the tissue specificity of gene expression, to generate models for human diseases (1,2), as well as to look at the consequences of oncogene expression (3 ...

Introduction of foreign molecules, such as DNA, RNA, or proteins, into living cells is a powerful means to test the biological functions of these molecules. One of the techniques by which foreign molecules can be introduced into living cells is electroporation (for reviews, see refs. 1,2). Compar ...

The ability to transfect mammalian cell lines stably in culture has enabled countless scientific advances to be made in just a few decades. However, not until about 10 years ago did the true potential for the genetic manipulation of cells become a reality, with the ability to alter a mammalian gene pre ...

The introduction of exogenous DNA into mammalian cells can ultimately result in the integration of the transfected DNA into the host genome (1,2). Any genes containing appropriate expression signals will, in most cases, be expressed both prior to and after integration. However, stable exp ...

In many situations, it is important to quantitate accurately expression of a transiently transfected gene. This is most often the case when mechanisms controlling gene expression are under study, and the roles of several possible promoter and enhancer elements and their interacting fa ...

The efficient production of proteins via expression of recombinant genes in cells other than those that naturally produce the protein has been critical to the study and the therapeutic utility of a wide variety of proteins. E. coli expression systems are useful for many proteins. However, large ...