摘要:

AbstractIonizing radiation increases the recipient's susceptibility to local and systemic infection by endogenous and exogenous microorganisms. Most infections involve fatal Gram-negative septicemia, but those associated with trauma may be polymicrobial. The use of quinolone antimicrobial agents in the treatment of these infections in irradiated mice is reviewed. Quinolones were effective in controlling systemic endogenous Gram-negative infection following irradiation. Supplementation of quinolone therapy with penicillin prevented treatment failures due toStreptococci, and increased survival. Quinolones were found also to be effective in management of systemic exogenous infections due to orally ingestedKlebsiella pneumoniaeandPseudomonas aeruginosa. A 21-day course of therapy ofK. penumoniaeinfection was superior to a 7-day therapy. The effectiveness of quinolones in the management of these infections may be attributed to local inhibition of the offending organism's growth within the gut lumen, while preserving the anaerobic gut flora and their systemic antibacterial activity. Administration of agents effective against anaerobic bacteria may be required for the management of polymicrobial infections. Supplementing antianaerobic therapy with a quinolone can control the Gram-negative bacterial component of the infection and prevent Enterobacteriaceae translocation and mortality. The availability of an oral, as well as parenteral, route of administration, the advantage of achieving selective inhibition of potential pathogens in the gut, and the ability to treat systemic infection make the quinolones promising agents for the therapy of endogenous and exogenous infections after irradiation.

ISSN:1040-841X    

DOI:10.3109/10408419209113516

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractInterest in the biology of theStreptomycesand application of these soil bacteria to production of commercial antibiotics and enzymes has stimulated the development of efficient cloning techniques and a variety of streptomycete plasmid and phage vectors.Streptomyces lividansis routinely employed as a host for gene cloning, largely because this species recognizes a large number of promoters and appears to lack a restriction system. Vector pIJ702 was constructed from a variant of a larger autonomous plasmid and is often used as a cloning vehicle in conjunction withS. lividans. The host range of vector pIJ702 extends beyondStreptomycesspp., and its high copy number has been exploited for the overproduction of cloned gene products. This combination of host and vector has been used successfully to investigate antibiotic biosynthesis, gene structure and expression, and to map variousStreptomycesmutants.

ISSN:1040-841X    

DOI:10.3109/10408419209113517

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractAliphatic linear polyamines, from diamines to hexaamines, tertiary branched tetraamines, and quaternary branched pentaamines are widely distributed in eubacteria, archaebacteria, and cyanobacteria. Twenty-four linear types and four branched types are acid extractable from bacterial cells and can be chromatographically analyzed and identified. The varieties of polyamines are due to the combination of amino acid decarboxylase activities to form diamines, aminopropyl- and aminobuty1-transfer activities mediated by aminopropy1transferases or Schiff-base complex formation, and hydroxylation activity. The absence or presence of spermidine, nor-spermidine or homospermidine and the occurrence of 2-hydroxyputrescine and diaminopropane are related to grouping into theα,β,γandδsubclasses withinProteobacteria. Flavobacteriumcomplex and green bacteria contain putrescine and homospermidine. Gram-negative thermophiles contain long linear and branched polyamines; however, their distribution profiles are species specific. Gram-positive eubacteria, which compriseBacilluscluster, anaerobes, and actinomycetes, ubiquitously contain putrescine and spermidine, while the occurrence of spermine is limited to thermophiles. Archaebacteria are separated into polyamine-absent meth-anogens and halophiles, homospermidine-dominant methanogens, spermidine-dominant methanogens, and spermidine- and norspermidine-containing thermophiles. Cyanobacteria comprise two types; one group contains homospermidine and the other spermidine. The polyamine distribution pattern can serve as a chemotaxonomic marker in bacterial classification and is associated with bacterial systematics on the level of order, family, or genus.

ISSN:1040-841X    

DOI:10.3109/10408419209113518

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor