实验基础

Mycoplasmas were first isolated from humans in 1937 (1), although it was not until 1951 (2) that selective media were used to identify mycoplasmas in the oropharynx. In 1962, an etiological link was established between what we now know to be Mycoplasma pneumoniae and cases of primary atypical pneu ...

Mycoplasmas are the smallest known free-living organisms, and adapted to a special mode of life as commensal organisms or opportunistic pathogens. Because of their small genome size, they have limited biosynthetic capacity, which means they lack many biochemical pathways found in the E ...

Mycoplasmas lack many of the biosynthetic pathways of higher organisms; consequently, their growth and survival depend on an external supply of a wide variety of nutrients. Because they are very fastidious in their nutritional requirements, a complex growth medium is required for their c ...

The existence of ureaplasmas, known formerly as T-strains, was first recognized in 1954 (1). Subsequently, it was found that these organisms possess the enzyme urease (2), a feature that made them unique among mollicutes and eventually led to their reclassification (3) within the new genus, Ure ...

The methods used for recovering mycoplasmas from birds are broadly similar to those described for other animals and for humans. Mycoplasmas are important causes of disease and loss of production in intensively reared poultry, particularly in those that are under environmental stress ( ...

Of the 30 or so mollicute species that have been isolated from small and large ruminants, only a handful have been shown to cause disease in their own right. This chapter will concentrate on methods for sampling, transporting, and isolating those pathogenic mycoplasmas, including Mycoplasma ...

Mollicutes include the smallest, free-living microorganisms. They are cell-wall-less bacteria, many of which produce disease in humans, animals, plants, or insects. Morphologically, mollicutes are extremely variable and pleomorphic, even in pure culture. Some organisms assu ...

To study the first stages of interactions between bacteria and mammalian host cells, it is necessary to locate the surface antigens involved in cytodhesion processes. The identification of a bacterial adhesin is normally based on experimental evidence of adherence inhibition in vitro ...

Membrane proteins of mycoplasmas assume particular significance in investigations of the pathogenesis of disease. They are involved in adhesion to, and probably in other interactions with, the cells of the target tissues of the host (1–5). They are frequently significant antigens in the i ...

Polyacrylamide gel electrophoresis (PAGE) of whole-cell proteins was first used for differentiation of mycoplasma species by Razin and Rottem (1) The method used was separation through 7.5% acrylamide gels containing 35% acetic acid and 5M urea. However, since the publication of Laemml ...

The expression of mycoplasma genes in Escherichia coli offers some interesting and unusual challenges compared to the expression of most other bacterial or eukaryotic cloned genes. For instance, the members of the genera Mycoplasma, Ureaplasma, and Spiroplasma all appear to utilize U ...

There are a range of methods that can be used to recover mycoplasmas from the infected sites of humans. The current standard method is culture on supplemented agar or broth media. The prolonged time for culture particularly for Mycoplasma pneumoniae, has necessitated a reliance by diagnostic ...

The expression of foreign genes in mollicutes has been difficult owing to inefficient transformation systems, and, until recently, by the lack of suitable cloning vectors. Few genes, excluding those associated with vector functions, have successfully been cloned and expressed in mol ...

Mycoplasmas are parasites and pathogens of plants, insects, and animals, including humans. Although mycoplasmas are highly evolved parasites, they are not immune to being parasitized themselves. Within the class Mollicutes, extrachromosomal elements have been described for s ...

Transposon mutagenesis, although utilized extensively in cell-walled bacteria, has been used rarely within the class Mollicutes (1). The reasons for such limited use include a lack of the necessary techniques and transposons that contain suitable antibiotic markers. There has been l ...

Transformation of mycoplasmas was not clearly demonstrated until 1987 when Dybvig and Cassell were able to show the introduction of the Gram-positive transposon Tn916 into Acholeplasma laidlawii and Mycoplasma pulmonis (1). This was the first direct evidence that mycoplasmas cou ...

Workers using cell cultures for research, diagnostics, or production of biopharmaceuticals have in common the need to maintain their cultures in a state of control. The living cell-culture system that is expected to produce reliably scientific and diagnostic data or a product must not be enc ...

Prokaryotic insertion sequences (IS) are transposable genetic elements with a length ranging from 800–2500 bp. They are found at a remarkable variety in the genomes of many different bacteria and mycoplasmas at a multiplicity of between a few and several hundred per genome. In bacteria, they a ...

In routine diagnosis, bacterial field isolates are identified by serological and/or biochemical tests. Occasionally, however, isolates deviate from the generally accepted patterns, i.e., they may react with diagnostic antisera of more than one type strain or fail to react with any of them, ...

The diagnosis and typing of microorganisms of human and veterinary significance are vitally important in the rapid and effective treatment of infectious diseases. Traditionally, the growth of bacteria in specific media and/or the immunological detection of surface antigens is us ...