摘要:

AbstractIn order for an infection to occur, the target organ must come in contact with sufficient microbes, the microbe must possess specific virulence factors, these virulence factors must be expressed, and the defenses of the organ system must be overcome. This dynamic process, which is ongoing in all living entities, can be described by the following relationshipThe establishment of infection first occurs in a particular organ. This phenomenon is known as tissue trophism and the association of microbes with organ systems governs the practice of clinical microbiology and infectious disease. With some microbes (e.g.,Giardia, Cryptosporidium) the interaction with the particular organ is so specific that infections are almost always confined to one site; with others (e.g.,Salmonella, enterovirus) the microbe has the potential to become systemic. When attempting to establish health risk assessment from microbes by contact with food and drinking water, one must therefore consider that the gastrointestinal tract is a complex organ system with a variety of specific host defense mechanisms. It is only when the microbe has particular virulence factors for sites in gastrointestinal tract, and the specific host defense mechanisms in the gastrointestinal tract are breached, that infection of this organ system occurs. Therefore, the general terms“immunosuppression”or“immunocompromise”are meaningless unless the specific immune defect is known. A description of the microbial virulence factors active against the gastrointestinal tract and die defense mechanisms of this organ system are reviewed to provide a biological basis health risk assessment and future food and drinking water regulations.

ISSN:1040-841X    

DOI:10.3109/10408419509113535

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractSingle-strand-specific nucleases, which act on single-stranded nucleic acids and single-stranded regions in double-stranded nucleic acids, are multifunctional enzymes and are ubiquitous in distribution. They find wide application as analytical tools in molecular biology research, although enzymes such as P1 nuclease are also used for production of flavor enhancers such as 5′IMP and 5′GMP. Because these enzymes are mainly used as analytical tools, very little attention was paid to aspects relating to their structure-function relationships. However, during the last few years considerable developments have taken place in this area. Single-strand-specific nucleases, their purification, characteristics, biological role, and applications have been reviewed.

ISSN:1040-841X    

DOI:10.3109/10408419509113536

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor