Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 344444
Title Microcalorimetric study on the influence of temperature on bacterial coaggregation
Author(s) Postcollec, F.; Norde, W.; Mei, H.C. van der; Busscher, H.J.
Source Journal of Colloid and Interface Science 287 (2005)2. - ISSN 0021-9797 - p. 461 - 467.
Department(s) Physical Chemistry and Colloid Science
Publication type Refereed Article in a scientific journal
Publication year 2005
Keyword(s) streptococcus-sanguis - actinomyces-viscosus - oral streptococci - heat-capacity - binding - saliva - hydroxylapatite - adherence - adhesion - pairs
Abstract Binding isotherms and heats of interaction have been determined at 15, 25, and 40°C for a coaggregating and a non-coaggregating oral bacterial pair. Heats of interaction were measured upon three consecutive injections of streptococci into an actinomyces suspension using isothermal titration calorimetry. After each injection, the number of streptococci injected remaining free in suspension was quantified microscopically and the degree of binding between the two bacterial strains was established. The coaggregating pair shows positive cooperative binding. The highest cooperativity, at 25°C, correlates with a strong, macroscopically visible coaggregation. The non-coaggregating pair shows low cooperativity and lacks macroscopically visible coaggregation. Interactions between the coaggregating partners seem to be mainly due to specific, enthalpically saturable and favorable binding sites. Even though the enthalpic part of the interaction is saturated, cooperativity increases with consecutive injections, implying that the coaggregation phenomenon is driven by entropy gain. The change in heat capacity (¿Cp) is positive for the non-coaggregating pair from 15-40°C as well as for the coaggregating pair beyond 25°C. At lower temperatures the coaggregating pair causes a negative ¿Cp. The decrease in heat capacity together with an increase in entropy is considered to be indicative of hydrophobic interactions playing an important role in the formation of large coaggregates as observed for the coaggregating pair at 25°C.
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