We previously described the isolation of mutants of the methylotrophic yeast Hansenula polymorpha that are defective in peroxisome biogenesis. Here, we describe the characterization of one of these mutants, per8, and the cloning of the PER8 gene. In either methanol or methylamine medium, conditions that normally induce the organelles, per8 cells contain no peroxisome-like structures and peroxis...

We previously described the isolation of mutants of the methylotrophic yeast Hansenula polymorpha that are defective in peroxisome biogenesis. Here, we describe the characterization of one of these mutants, per8, and the cloning of the PER8 gene. In either methanol or methylamine medium, conditions that normally induce the organdies, per8 cells contain no peroxisome-like structures and peroxiso...

Understanding the functions encoded by plant genes can be facilitated by reducing transcript levels by hairpin RNA (hpRNA) mediated silencing. A bottleneck to this technology occurs when a gene encodes a phenotype that is necessary for cell viability and silencing the gene inhibits transformation. Here we compared the use of two chemically inducible plant promoter systems to drive hpRNA mediate...

4 A defective eigenvalues is well documented to be hypersensitive to data pertur5 bations and round-off errors, making it a formidable challenge in numerical computa6 tion particularly when the matrix is known through approximate data. This paper 7 establishes a finitely bounded sensitivity of a defective eigenvalue with respect to per8 turbations that preserve the geometric multiplicity and th...

1 An analytical evaluation of six widely used term weighting techniques for text cate2 gorization is presented. The analysis depends on expressing the term weights using term 3 occurrence probabilities in positive and negative categories. The weighting behaviors of 4 the schemes considered are firstly clarified by analyzing the relation between the occur5 rence probabilities of terms which rece...

Although the tobacco N gene, which confers resistance to Tobacco mosaic virus (TMV), is transcriptionally induced by infection with TMV, the regulatory mechanism has not previously been elucidated. We found that a 5¢-flanking region of the N gene exhibits TMVinducible promoter activity and that the region from )290 to )271 includes a cis-acting element in response to infection. The activity req...