摘要:

Copper ions inhibit growth ofAmphora coffeaeformisbut are not lethal even after lengthy exposure at high concentrations. Growth inhibition is attributed primarily to copper bound to different types of sites on the cell surface which exhibit different binding strengths. Removal of weakly bound copper, by placing the cells in fresh medium or treating with EDTA, results in a partial reversal of toxicity. A minor fraction but important component of the external cellular copper is bound more tightly. When this copper is removed, by displacement with H+ions or cysteine, toxicity is completely reversed. Reversal of toxicity depends on the form of the copper moiety. Whereas copper toxicity may be readily reversed for copper (II) ions from either soluble copper salts or insoluble Cu2O and CuSCN it cannot be reversed for lipid‐soluble copper complexes. Entry of such complexes into the cell results in cell death.

ISSN:0892-7014    

DOI:10.1080/08927019009378144

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The initial rate of acetoclastic methanogenic biofilm formation was significantly higher than rates that have been reported for mixed anaerobic cultures. Biofilm development rate increased with an increase in biomass concentration and specific activity (mg substrate‐mg biomass−1‐day−1) of the mixed liquor biomass. Biofilm concentration also increased with higher specific activity. Results indicate the involvement of polysacchar‐ides in acetoclastic biofilm formation. The existence of a loosely held biofilm at flow velocities of 005 to 1–5 cm‐s−1was observed. Flow velocity increases in that range resulted in higher attached film accumulation rates. Silicone tubing was superior to Tygon tubing in facilitating biofilm formation.

ISSN:0892-7014    

DOI:10.1080/08927019009378145

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Dielectric spectroscopy can be used as an on‐line method for the measurement of the formation of biofilms. The formation of a biofilm by the organismKlebsiella rubiacearumwas measured by registering changes in the capacitance in the frequency range 0–1–10 MHz using a 4‐terminal gold pin dielectric spectrometer. Removal and prevention of biofilms by electrolytic cleaning pulses was investigated. The effect of the addition of the biocides cetrimide, chlorine and glutaraldehyde was studied. The usefulness of the method in the on‐line control of biofilms was demonstrated in an experiment in which the biofilm level was controlled by the automated addition of chlorine in response to appropriate changes in the electrical capacitance.

ISSN:0892-7014    

DOI:10.1080/08927019009378146

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

From December 1986 to November 1987 a biofouling panel test was carried out at Daya Bay, China (114°39'E; 22°40'N). A total of 83 species were encountered. The major dominants wereBugula neritina, Sinupetraliella umbonatoidea, Schizoporella unicornis, Hydroides elegans, Spirorbissp.,Ostrea radix, O. pestigris, Balanus reticulatus, B. amphitrite amphitrite, B. trigonusandB. cirratus. Bioattachment occurred over the whole year but it was distinctly seasonal. The most prolific period was May to October. The summer (Jun‐Aug) wet weight was 6·25 kgm−2but the second semiannual (Jun‐Nov) wet weight was the greatest, reaching 40–79 kg·M2.

ISSN:0892-7014    

DOI:10.1080/08927019009378147

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This review describes the surface structures (fibrils and fimbriae), on oral bacteria that can be responsible for adhesion to buccal mucosa, teeth and other bacteria (coaggregation). Fibrils and fimbriae have been found on a number of different speciesof Streptococcus, ActinomycesandBacteroides, and are morphologically and biochemically distinct from each other. Either structure can be present on different strains of the same species ofStreptococcus. Fibrils or fimbriae are present on different species ofBacteroides, andActinomycesspecies only exhibit fimbriae. The evidence for the existence of two distinct types of surface structure is evaluated. Fimbriae are flexible peritrichous structures composed of protein, with sub‐unit molecular weights varying from 43 kDa forBacteroides gingivalis381 fimbriae, to 65 kDa forActinomyces viscosusT14V fimbriae. Fimbriae are thin (3–5 nm wide) and are characterised by a definite width all along their length. Fibrils can be either peritrichous, or less commonly arranged in lateral tufts, and they have a reproducible length (<400 nm) that is strain‐dependent. Fibrils are characterised by their ability to clump in negative stain, so that individual widths cannot be measured. Fibrils are glycoprotein in nature with a sub‐unit molecular weight ranging from 220 kDa for the fibrillar host adhesion factor fromStreptococcus salivariusHB, to 320 kDa for the fibrillar veillonella binding protein, also fromS. salivariusHB. Some fibrils and fimbriae carry multiple adhesins adhering to more than one type of receptor. The evidence linking fibrils and fimbriae with adhesion to oral surfaces is assessed.

ISSN:0892-7014    

DOI:10.1080/08927019009378148

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0892-7014    

DOI:10.1080/08927019009378143

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor