The aim of the present study was to examine the feasibility of DNA microarray technology in an attempt to construct an evaluation system for determining gas toxicity using high-pressure conditions, as it is well known that pressure increases the concentration of a gas. As a first step, we used yeast (Saccharomyces cerevisiae) as the indicator organism and analyzed the mRNA expression profiles after exposure of yeast cells to nitrogen gas. Nitrogen gas was selected as a negative control since this gas has low toxicity. Yeast DNA microarray analysis revealed induction of genes whose products were localized to the membranes, and of genes that are involved in or contribute to energy production. Furthermore, we found that nitrogen gas significantly affected the transport system in the cells. Interestingly, nitrogen gas also resulted in induction of cold-shock responsive genes. These results suggest the possibility of applying yeast DNA microarray to gas bioassays up to 40 MPa. We therefore think that "bioassays" are ideal for use in environmental control and protection studies.
Key words: DNA microarray, Yeast, Hydrostatic pressure, Gas pressure, Nitrogen gas
While seeking a comfortable living environment, the human race has been continuously releasing large quantities of pollutants into the environment, consequently causing various problems such as air, water, and soil pollution. Although emission of pollutants is being gradually reduced by the recent tighter control of emissions of environmental pollutants, we are still polluting our environment. The problem is further compounded by the fact that we are not dealing with a single pollutant, but with a mixture of pollutants in the environment, and therefore it is rather difficult to recognize their effects on organisms. Methods that can determine their effect primarily include physiochemical analyses and bioassays. When pollution is supposed to be present to some extent, we can use physicochemical analyses as a qualitative and quantitative tool for a single substance; however, this is not useful for the assessment of the impact of tens of millions of chemical substances on the environment. Although we cannot determine the concentration of each chemical substance by bioassay, it is possible to do rapid toxicity and genetic toxicity analysis using animal organisms (mammals such as rodents, fish and shellfish, algae, single cells, etc.) because it focuses attention on the effect on organisms.
We have studied a bioassay for the hydrosphere using a yeast DNA microarray. In the present study, drawing on our previous experience, we attempted to develop a bioassay system for polluted air monitoring. By using yeast (Saccharomyces cerevisiae S288C), suitable for rapid toxicity assessment, we can monitor genome-wide gene expression profiles by DNA microarray after exposing yeast cells to high-pressure gas. Thus, we believe it will be possible to assess the impact of polluted gases within short periods of time.
In the present report, we focus mainly on nitrogen gas, a component of our life-supporting air in the environment. Our results revealed significant changes in gene expression profiles, such as those involved in the membrane system, energy, cellular transport, and even cold-response. Since we were able to detect and characterize the response, we conclude that we may use high-pressure gas conditions for gas bioassay up to 40 MPa.
US 7033781 B1
RESUMO
An invention comprising cellular transformation, directed evolution, and screening methods for creating novel transgenic organisms having desirable properties. Thus in one aspect, this invention relates to a method of generating a transgenic organism, such as a microbe or a plant, having a plurality of traits that are differentially activatable. Also, a method of retooling genes and gene pathways by the introduction of regulatory sequences, such as promoters, that are operable in an intended host, thus conferring operability to a novel gene pathway when it is introduced into an intended host. For example a novel man-made gene pathway, generated based on microbially-derived progenitor templates, that is operable in a plant cell. Furthermore, a method of generating novel host organisms having increased expression of desirable traits, recombinant genes, and gene products.
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