Affiliation:
1. Institut für Bodenbiologie, Bundesforschungsanstalt für Landwirtschaft, 38116 Braunschweig, Germany
Abstract
ABSTRACT
Interaction potentials between soil microarthropods and microorganisms were investigated with
Folsomia candida
(Insecta, Collembola) in microcosm laboratory experiments. Microscopic analysis revealed that the volumes of the simple, rod-shaped guts of adult specimens varied with their feeding activity, from 0.7 to 11.2 nl. A dense layer of bacterial cells, associated with the peritrophic membrane, was detected in the midgut by scanning electron microscopy. Depending on the molting stage, which occurred at intervals of approximately 4 days, numbers of heterotrophic, aerobic gut bacteria changed from 4.9 × 10
2
to 2.3 × 10
6
CFU per specimen. A total of 11 different taxonomic bacterial groups and the filamentous fungus
Acremonium charticola
were isolated from the guts of five
F. candida
specimens. The most abundant isolate was related to
Erwinia amylovora
(96.2% DNA sequence similarity to its 16S rRNA gene).
F. candida
preferred to feed on
Pseudomonas putida
and three indigenous gut isolates rather than eight different type culture strains. When luciferase reporter gene-tagged bacterial strains were pulse fed to
F. candida
, gut isolates were continuously shed for 8 days to several weeks but
Escherichia coli
HB101 was shed for only 1 day. Ratios of ingested to released bacterial cells demonstrated that populations of nonindigenous gut bacteria like
Sinorhizobium meliloti
L33 and
E. coli
HB101 were reduced by more than 4 orders of magnitude but that the population of gut isolate
Alcaligenes faecalis
HR4 was reduced only 500-fold. This work demonstrates that
F. candida
represents a frequently changeable but selective habitat for bacteria in terrestrial environments and that microarthropods have to be considered factors that modify soil microbial communities.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
86 articles.
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