微生物学技术

Bacterial taxonomy comprises systematics (theory of classification), nomenclature (formal process of naming), and identification. There are two basic approaches to classification. Similarities may be derived between microorganisms by numerical taxonomic methods bas ...

Methods for isolation of small plasmids (usually cloning vehicles) from genetically characterized strains of Enterobacteriaceae (Escherichia coli and Salmonella) are well established (1–3). This chapter seeks to complement them by describing reliable basic methods for det ...

This chapter describes a simple method of making DNA probes with a nonisotopic label. The development of this type of new technology has, for example, created novel ways of detecting and identifying pathogenic microorganisms, which has led to a re-evaluation of methodological approaches ...

Antibiotic resistance is not an absolute property. Even within a single species, strains can exhibit different degrees of antibiotic resistance. When a bacterium is tested for resistance, it should be compared, quantitatively with a standard. This standard may be the resistance of a wild- ...

Plasmids are extra-chromosomal molecules of deoxyribonucleic acid (DNA) capable of autonomous replication. Such molecules have been identified in many bacterial genera and usually exist as covalently closed circular (CCC) molecules. Plasmids range in size from less than one meg ...

Traditional methods for the identification of some bacterial species can be time consuming and often necessitate the isolation of pure cultures before further characterization may be undertaken. Advances in molecular biology have allowed the identification of bacterial spec ...

Polymerase chain reaction (PCR) can be used to identify microorganisms in at least two basic ways. The first method depends on a knowledge of DNA sequence unique to the organism under study and provides a specific means of identifying that organism. This method is discussed elsewhere in this volu ...

DNA probes are being used increasingly to detect and identify microorganisms, particularly pathogenic bacteria in a variety of areas. These include medicine, the food industry, and the environment. Various strategies have been used to develop DNA probes for specific bacteria that inc ...

Bacteriophages (phages) are viruses that infect bacteria. Susceptibility to infection by particular phages varies between strains within a species, and this property can be exploited to construct highly discriminatory schemes for the type identification of strains in epidemi ...

Bacteriocins are proteins produced by bacteria which are lethal for other members of the same species and, occasionally, for other species. In general, bacteriocins are active in very low concentrations against specific strains. This property has been widely utilized for the identifi ...

Polyacrylamide gel electrophoresis (PAGE) of proteins has been used increasingly during the past decade in the examination of bacteria for both comparative purposes and in the study of their protein biochemistry at the molecular level. The most popular of the techniques employed, disc ...

Lipopolysaccharide (LPS), traditionally termed somatic antigen or O-antigen, forms an integral part of the outer membrane of Gram-negative bacteria. In general, LPS consists of essentially three parts: 1. A hydrophobic portion, lipid A,

The cell envelope of Gram-negative bacteria comprises an inner and an outer membrane separated by a layer of peptidoglycan (Fig. 1). The inner membrane is the site of biochemical reactions involved in respiration and oxidative phosphorylation, and the synthesis of structural membrane c ...

Pyrolysis of microorganisms yields complex mixtures of products that can be analyzed quantitatively by mass spectrometry (MS). The resulting mass spectra represent transient bacterial “fingerprints” that can be compared mathematically for relatedness. The method has poten ...

Mass spectrometry (MS) is a chemical analytical technique that can yield data in the form of a spectrum of peaks of differing relative intensities and over a range of mass-to-charge (m/z) values. Such data permit calculation of molecular weight and molecular structure. The technique has been us ...

Of the world’s infectious diseases, tuberculosis remains the leading cause of mortality and it has been estimated that of the eight million new cases that occur each year 95% are found in the less developed countries (1,2). Diagnostic methods that involve culture of Mycobacterium tuberculos ...

Genomic variation in any organism is of interest, because it may influence the phenotype of the organism. Special interest currently focuses on prokaryotic pathogens regarding mutations associated with resistance to therapeutic drugs, as well as those mutations involved in the evo ...

In principle, restriction fragment length polymorphism (RFLP) typing can be applied to strains of all mycobacterial species for which suitable probes have been identified. International consensus has been achieved regarding the methodology of IS6110 RFLP typing of Mycobacter ...

Culture filtrates obtained by in vitro cultivation of Mycobacterium tuberculosis have been studied for more than 20 years to identify and characterize proteins of immunological relevance. Culture filtrate preparations have been shown to induce a protective immune response in mi ...

Mycobacterium tuberculosis and the other pathogenic mycobacteria examined so far by electron microscopy are seen to be surrounded within host cells by an electron-transparent zone (ETZ). For Mycobacterium lepraemurium, this space between the phagosomal membrane of the infected ...