摘要:

Essential oil of clove, dispersed (0.4%v/v) in a concentrated sugar solution, had a marked germicidal effect against various bacteria andCandida albicans. Staphyloccus aureus(five strains),Klebsiella pneumoniae, Pseudomonas aeruginosa, Clostridium perfringens, andEscherichia coliinoculated at a level of 107cfu/ml, andC. albicans(inoculum 4.0×105cfu/ml) were killed (<99.999%) after 2–7 min in a laboratory broth supplemented with 63% (v/w) of sugar, and containing 0.4% (v/w) of essential oil of clove. Added organic matter (i.e. human or bovine serum) did not impair its antimicrobial activity.Sugar was not necessary for the antimicrobial activity of clove oil, but the concentrated sugar solution provided a good vehicle for obtaining an oil dispersion that is relatively stable for certain practical applicatio

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1989.tb02456.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Compared with cultures grown aerobically in batch culture with glucose, aerated cultures of lactic streptococci had a less homolactic type of metabolism when galactose was the carbohydrate source in batch cultures, or when glucose was limiting in chemostat cultures. Differences in end‐products of sugar metabolism between aerated and unaerated cultures were observed. In addition to lactate, formate, acetate and ethanol were produced in anaerobic cultures, whereas acetate and acetoin were formed in aerated cultures. Acetate production in aerated cultures depended on lipoic acid, an essential cofactor of the pyruvate dehydrogenase complex. In a chemically defined medium with glucose as the energy substrate, lipoic acid (or acetate) was an essential growth factor. Formation of acetoin was inversely related to lipoic acid concentration in the growth medium. Although not observed in unaerated cultures, acetoin (and 2,3‐butanediol) was produced in unaerated buffered suspensions metabolizing pyruvate. Aeration caused a modest increase in the activities of aP‐acetolactate synthetase and phosphate acetyl trans‐ferase, but it is unlikely that the increases were sufficient to account for the changes in end‐products of sugar metabolism

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1989.tb02457.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The presence of Methanobrevibacter smithii altered the susceptibility of the anaerobic fungi Neocallimastix frontalis and Piromonas communis to the carboxylic ionophores monensin and lasalocid. The ionophores depressed growth (measured by chitin accretion), the uptake of glucose and the production of H2, formate and acetate by the fungi growing axenically in semi‐solid medium. In the presence of M.smithii, the sensitivity of the fungi to monensin and lasalocid was decreased. For example, the uptake of glucose by N. frontalis strain RE1 in the culture was reduced to 50% of the control value by monensin at 0.5 mUg/ml. In the presence of M.smithiistrain PS, approximately three tunes as much monensin was needed to bring about the same effect. In similar tests, the sensitivity of strain RE1 to lasalocid was decreased about nine‐fold in the presence of M.smithii.The effect was not observed if the methanogens were killed by autoclaving before inoculation. It is suggested that the enhanced resistance to ionophores in the presence of M.smithiiis a consequence of changes in the energy metabolism of the fungi growing in co‐cu

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1989.tb02458.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY