Bright, John (1983) The physiological activity of attached bacteria. PhD thesis, University of Warwick.

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Abstract

Assimilation and respiration by a marine Pseudomonas sp. was
evaluated to determine whether the activity of bacteria attached to
solid surfaces (substrata) differed from that of free-living bacteria.
Bacteria were allowed to attach to glass and plastic substrata with a
range of wettabilities, evaluated by measuring water contact angles.
Amino acid assimilation was determined by microautoradiography and
liquid scintillation counting, and respiratory activity was determined
from 14CO2. evolution and electron transport system (ETS) activity
evaluated by tetrazolium staining. The uptake kinetics of leucine
demonstrated thatfree-living cells had a smaller half-saturation
constant than any of the surface-associated populations but a somewhat greater
maximum velocity of uptake than the cells associated with all but the
most hydrophobic substratum. Pre-attachment incubation of free-living
bacteria with 3H-leucine resulted in the subsequent attachment to all
the substrata of approximately a four fold higher percentage of labelled
bacteria as compared with populations that remained unattached. When
incubated with amino acids at a concentration of l0μg C l-1 after
attachment, the proportion of attached bacteria that assimilated amino
acids and the rate of assimilation per cell, was greater than, or
similar to, that of free-living bacteria. However, the proportion of
attached bacteria that demonstrated ETS activity and the rate of 14CO2
respired per surface-associated cell, was less than, or similar to,
that of free-living bacteria. There was little relationship between
substratum wettability and the activity of attached bacteria at low
substrate concentrations (≤ 10μg C l-1) but in the presence of higher
leucine concentrations the proportion of attached bacteria that
assimilated leucine and demonstrated ETS activity increased with
substratum hydrophilicity. The relative activities of attached and
free-living bacteria depended upon the substrate, its concentration
and the substratum properties. However, the efficiency of substrate
utilisation by attached bacteria was generally greater than that for
free-living bacteria.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QR Microbiology
Library of Congress Subject Headings (LCSH):	Pseudomonas -- Respiration, Pseudomonas -- Physiology
Official Date:	November 1983
Dates:	Date Event November 1983 Submitted
Institution:	University of Warwick
Theses Department:	Department of Biological Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Fletcher, Madilyn ; Marshall, Kevin C.
Sponsors:	Natural Environment Research Council (Great Britain) (NERC)
Extent:	xv, 104 p.
Language:	eng

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