数据库

Killer toxin activity is commonly determined by the well test (1), which ensures the inhibition zone on a substratum of sensitive strain cells. The Rhodamine B assay described in Chapter 31 is based on estimation of the fraction of killed cells, which stain with the fluorescent dye Rhodamine B. Neve ...

The “killer plaque” technique (1) appears to be the simplest of all versions of the selection procedure (2), based on application of killer toxins, that have been examined in our laboratory (see Chapter 33). The procedure is based on the observation that the selection of killer hybrids, cybrids, or tr ...

The most current method for selecting hybrid yeast clones obtained by means of protoplast fusion or transformation procedures is based on the auxotrophy of manipulated strains. Unfortunately, preparation of auxotrophic mutants without damage to the rest of the genome is time consumi ...

During the last 20 yr, the established molecular relationship between mutagenicity and carcinogenicity has been exploited in the development of numerous microbial tests designed to detect mutagenic activity and hence predict carcinogenic activity in industrial and environ ...

Cytochrome P450s (cyt.P450s) are a class of hemoprotein enzymes found in a wide variety of organisms, where they play an important role in endogenous metabolism and the metabolism of xenobiotic compounds. In eukaryotes these enzymes are membrane-bound, in most cases located in the endopla ...

The molecular biology of yeasts places increasing emphasis on the genetic and biochemical complexity of the cell in the contest of its spatial organization. This development has led to a renaissance of yeast cytology. Classical cytological methods are being replaced by new techniques pa ...

Microcalorimetry provides a quick and accurate nonspecific technique for the direct measurement of metabolic activity of biological cells either under growth or nongrowth conditions. The method has added advantages such as good reproducibility, no requirement for optically t ...

The last decade has seen an extraordinary improvement in fluorescence microscopy instruments. These have been mainly in the development of epi-illumination systems, including dichroic beam splitters, matching excitation and barrier filters, and special objectives (see ref. 1 f ...

Mutations of numerous types can be induced in yeast. The basic principle is to bring the yeast in contact with the mutagen (UV light, X-rays, EMS, MMS, nitrous acid, nitrosoguanidine , ICR-170, nitrogen mustard, and so on), for long enough to bring about 50–95% killing, after which the mutagen is removed. The y ...

The immunolocalization of proteins on sections of biological materials that have been prepared for electron microscopy, requires the preservation of both antigenic and morphological structures. In this chapter, two techniques that fulfill these requirements, often difficu ...

Rare-mating is an adaptation of techniques used for normal classical mating in yeasts. It was first used to study the switching of mating types in Saccharomyces cerevisiae by Gunge and Nakatomi (1), but was later adapted to the investigation of industrial yeasts that have low mating frequencies ...

Diploid strains of asci, placed on suitable medium, sporulate and form four haploid spores/ascus, which may be arranged as tetrahedra, diamonds, or linearly. Strains forming linear arrays of spores in the ascus are rare, dissection of the asci with the micromanipulator is difficult, so the met ...

Saccharomyces cerevisiae can exist as either a haploid cell of either Mat a or Mat α mating type, a diploid cell or a polyploid cell, but the transfer of genetic material is normally restricted to conjugation between haploids of opposite mating type. It is possible, however, to isolate genetically s ...

Many yeast researchers are reluctant to embrace micromanipulation because of its reputation as a somewhat testing black art. However, as strain construction, meiotic mapping, cell and zygote isolation, pedigree studies, and other experiments are powerful weapons in the armory of the g ...

The development of electrophoretic techniques for separating intact chromosomal DNA from lower eukaryotes has provided a powerful system for analyzing the karyotypes of these organisms. Before the advent of pulsed field gel electrophoresis (1), the study of lower eukaryotic chro ...

Pulsed-field (gradient) gel electrophoresis (now abbreviated to PFGE or PF) was first described by Schwartz and Cantor (1) and Carle and Olson (2) in 1984. It allows separation of DNA molecules in the size range 50 kb to approx 10 Mb in agarose gels to which electric fields are applied in different directi ...

It is early to fully reflect on the state of the art in high content screening (HCS), because it is still a relatively new approach in drug discovery. Although the development of the first microscopes are a century old and the first confocal microscope is only 20 yr old, the fluorescent probes used within HCS a ...

High content screening (HCS) was created in 1996 to offer a new platform that could be used to permit relatively high-throughput screening of cells, in which each cell in an array would be analyzed at a subcellular resolution using multicolored, fluorescence-based reagents for both specifi ...

Microscopy has been a cornerstone of discovery in the academic life sciences for more than 100 yr. This comes from a unique ability to provide extremely rich information of biological structure and dynamics. The advent of digital imaging and machine vision has brought within itself the ability ...

The CellCard™ system enables the analysis of multiple cell types within a single microtiter well. In doing so, the CellCard system not only determines the effect of an experimental condition on a cell type of interest, but also the relative selectivity of that response across nine other cell types. ...