微生物学技术

The process of homologous recombination IS essential to all living organisms. It is important for the generation of genetic diversity, the maintenance of genomic integrity, and the proper segregation of chromosomes. At least 25 gene products (RecA, helicases, nucleases, ligases, sing ...

Mobile generic elements are discrete DNA fragments encoding their own transposltlon functions, which enable them to move from one site in the DNA to another, independently of host-recombination functions (such as RecA). Recombination by transposition occurs without homology bet ...

The creation and characterization of mutations within mycobacterial genomes is crucial for the analysis of gene function and regulation in members of the species. Such mutants could be used to elucidate mechanisms of virulence and survival of pathogenic mycobacteria such as Mycobac ...

Mycobacteriophages are viruses that infect the mycobacteria Historically, they have been used to overcome major road blocks in the genetic manipulation of mycobacteria. Mycobacteriophages have been used to demonstrate mycobacterlal transfection (1) and transduction (2). A ...

The study of mycobacterial genomes has exploded during the last 10 yr. Initially, no systems were available for the du-ect manipulation of mycobacterial genes in mycobactena, so Escherichia coli was used as the primary cloning host. Several genomic libraries were created (1–5) in E. coli. Alth ...

Bacterial conjugation is a phenomenon that is more widespread than was originally thought. It medtates genetrc exchange not only between cells of the same species, but also between a wide variety of unrelated organisms. Conjugation between gram-negative and gram-positive bacteria w ...

A significant proportion of the world’s population is infected with Mycobacterium tuberculoszs, with estimates in 1992 of 8 million new mfections and 3 million deaths from tuberculosis (TB) per annum (1). There are several other causes for concern. There IS a close assoclatlon between the hum ...

MycDB 1s an integrated mycobacterial database. This means that it contains information on all aspects of mycobacteria, whether immunology, metabolism, or the researchers working on mycobacteria. For historical reasons, the starting point has been molecular biology, but other asp ...

Research extending over 50 years has implicated various components of the mycobacterial cell-wall matrix in many host responses associated with tuberculosis and other mycobacterioses (1). The observed responses originally included granuloma formation, high-titer IgG ant ...

Much work in the mycobacterial field has focused on the identification and characterization of antigenic proteins (1,2); many have now been identified and assigned a function; for example, the immunodommant 65kDa antigen of Mycobacterzum tuberculosis has been identified as a chaper ...

Genetic characterization of mycobacteria has advanced considerably in the last decade. The identificatlon of putative virulence genes and their products has prompted investlgation of how expression of these factors is controlled during infection. Regulation of virulence de ...

The introduction of pulsed field gel electrophoresis (PFGE) was a major breakthrough in the field of genome research (1), allowing the analysis of whole procaryotic and eucaryotic chromosomes. This became possible by a combination of new techniques for the extraction of intact chromoso ...

Characterization of recombinant mycobacterial genes has been complicated by the lack of a rapid and efficient method to prepare plasmid and cosmid DNA directly from mycobacteria. Traditionally, plasmids and cosmids had to be recovered from mycobacteria and propagated in Escheric ...

The Mycobacterium genus is comprised of over 30 mdivldual species with a large majority being saphrophytes. However, research on these bacteria has focused primarily on the pathogens Mycobacterium bow, Mycobacterium tuberculosis, and Mycobacterium leprae, and opportunistic ...

Prior to this decade, routine antibiotic-susceptibility testing (AST) of Mycobacterium tuberculosis clinical isolates was not advocated (1) This policy was predicated on the following assumptions: 1. The prevalence ofantibiotic resistance is low,

The discovery of polymorphic, repetitive DNA in the Mycobacterzum tuberculosis complex has led to many methods for differentiating clinical isolates belonging to this spectes of pathogenic bacteria. The most widely used method 1s restriction fragment-length polymorphism (R ...

Although a tumor cell can be distinguished from its normal counterpart by a wide range of phenotypic alterations, only a few of these properties provide useful indicators of malignant transformation. These include changes in cellular morphology, decreased dependence on serum growth ...

Retroviral vectors for polyomavirus tumor antigens, including SV40 large and small tumor antigens (SVT), have been extensively utilized to study the function of these proteins in a wide range of cell types. Properties of retroviruses that make them particularly efficient vectors incl ...

Murine preadipocyte cell lines represent a convenient and informative model system for determining whether the mechanisms underlying oncogene-induced neoplastic transformation and the suppression of terminal differentiation are related. Preadipocytes transfor ...

p53 was discovered because of its capacity to bind to SV40 large T antigen (SVLT) in transformed cell lines (1,2). It is a phosphorylated, 393 amino acid protein, with five blocks of sequences that are highly conserved throughout evolution. Early research showed that p53 could act as a dominant oncog ...