Grazing of attached bacteria by heterotrophic microflagellates

1987 ◽  
Vol 13 (3) ◽  
pp. 203-218 ◽  
Author(s):  
David A. Caron
Keyword(s):  
Attached Bacteria ◽  
Heterotrophic Microflagellates

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

Attachment of Shiga Toxigenic Escherichia coli to Beef Muscle and Adipose Tissue

2006 ◽  
Vol 69 (5) ◽  
pp. 999-1006 ◽  
Author(s):  
LUCIA RIVAS ◽  
GARY A. DYKES ◽  
NARELLE FEGAN
Keyword(s):  
Escherichia Coli ◽  
Adipose Tissue ◽  
Foodborne Pathogens ◽  
Gastrointestinal Disease ◽  
Attached Bacteria ◽  
The Mean ◽  
Bacterial Hydrophobicity ◽  
Adipose Tissue Cells ◽  
Selection Of ◽  
Beef Muscle

Shiga toxigenic Escherichia coli (STEC) serotypes are important foodborne pathogens that cause gastrointestinal disease worldwide. An understanding of how STEC strains attach to surfaces may provide insight into the potential persistence of and contamination with STEC in food environments. The initial attachment of a selection of STEC serotypes to beef muscle and adipose tissue was evaluated for isolates grown in planktonic and sessile culture. Initial experiments were performed to determine whether attachment differed among STEC strains and between the two modes of growth. Viable counts were obtained for loosely and strongly attached cells, and the strength of attachment (Sr) was calculated. All bacterial isolates grown in sessile culture attached in higher numbers to muscle and adipose tissue than did bacteria in planktonic cultures. For all attachment assays performed, mean concentrations for loosely attached cells were consistently higher than concentrations for strongly attached cells. The mean concentrations for strongly attached bacteria for planktonic and sessile cultures were significantly higher (P < 0.05) on adipose than on muscle tissue. However, some strains of STEC, particularly those from sessile culture, did not differ in their attachment to muscle or adipose tissue. Sr values were not significantly different (P > 0.05) among STEC isolates for all assays. No correlation was found between bacterial hydrophobicity and surface charge values (previously determined) and production of surface structures, viable counts, and Sr values. STEC grown in planktonic and sessile culture seems to behave differently with respect to attachment to muscle and adipose tissue. Cells in sessile culture may have a greater potential to strongly attach to meat surfaces.

scholarly journals Diversity of Free-Living and Attached Bacteria in Offshore Western Mediterranean Waters as Depicted by Analysis of Genes Encoding 16S rRNA

1999 ◽  
Vol 65 (2) ◽  
pp. 514-522 ◽  
Author(s):  
Silvia G. Acinas ◽  
Josefa Antón ◽  
Francisco Rodríguez-Valera
Keyword(s):  
16S Rdna ◽  
Restriction Analysis ◽  
Western Mediterranean ◽  
Bacterial Cells ◽  
Free Living ◽  
Attached Bacteria ◽  
Genes Encoding ◽  
Community Fingerprinting ◽  
Close Relatives ◽  
Alteromonas Macleodii

ABSTRACT In a previous study (S. G. Acinas, F. Rodrı́guez-Valera, and C. Pedrós-Alió, FEMS Microbiol. Ecol. 24:27–40, 1997), community fingerprinting by 16S rDNA restriction analysis applied to Mediterranean offshore waters showed that the free-living pelagic bacterial community was very different from the bacterial cells aggregated or attached to particles of more than about 8 μm. Here we have studied both assemblages at three depths (5, 50, and 400 m) by cloning and sequencing the 16S rDNA obtained from the same samples, and we have also studied the samples by scanning electron microscopy to detect morphology patterns. As expected, the sequences retrieved from the assemblages were very different. The subsample of attached bacteria contained very little diversity, with close relatives of a well-known species of marine bacteria, Alteromonas macleodii, representing the vast majority of the clones at every depth. On the other hand, the free-living assemblage was highly diverse and varied with depth. At 400 m, close relatives of cultivated γProteobacteria predominated, but as shown by other authors, near the surface most clones were related to phylotypes described only by sequence, in which the α Proteobacteria of the SAR11 cluster predominated. The new technique of rDNA internal spacer analysis has been utilized, confirming these results. Clones representative of the A. macleodii cluster have been completely sequenced, producing a picture that fits well with the idea that they could represent a genus with at least two species and with a characteristic depth distribution.

scholarly journals Activity and distribution of attached bacteria in Chesapeake Bay

1994 ◽  
Vol 108 ◽  
pp. 1-10 ◽  
Author(s):  
P Griffith ◽  
F-K Shiah F ◽  
K Gloersen ◽  
HW Ducklow ◽  
M Fletcher
Keyword(s):  
Chesapeake Bay ◽  
Attached Bacteria

scholarly journals Assessment of a weak mode of bacterial adhesion by applying an electric field

2020 ◽  
Author(s):  
George Araujo ◽  
Joy Zheng ◽  
Jae Jong Oh ◽  
Jay X. Tang
Keyword(s):  
Electric Field ◽  
Environmental Control ◽  
Caulobacter Crescentus ◽  
Surface Interaction ◽  
Bacterial Attachment ◽  
Stick Slip ◽  
Attached Bacteria ◽  
Plastic Surface ◽  
Unique Approach ◽  
Microbial Attachment

ABSTRACTMicrobial attachment to surfaces is ubiquitous in nature. Most species of bacteria attach and adhere to surfaces via special appendages such as pili and fimbriae, the roles of which have been extensively studied. Here we report an experiment on pilus-less mutants of Caulobacter crescentus weakly attached to a plastic surface and subjected to an electric field parallel to the surface. We find that some individual cells transiently but repeatedly adhere to the surface in a stick-slip fashion in the presence of an electric field. Even while transiently detached, these bacteria move significantly slower than the unattached ones in the same field of view undergoing electrophoretic motion. We refer this behavior of repeated and transient attachment as “quasi-attachment”. The speed of the quasi-attached bacteria exhibits large variations, frequently dropping close to zero for short intervals of time. This study suggests applying electric field as a useful method to investigate bacteria-surface interaction, which is significant in broader contexts such as infection and environmental control.SignificanceInteraction between bacteria and surfaces occur widely in nature, including those in industrial, environmental, and medical settings. It is therefore important to understand various mechanisms and factors that affect numerous forms of bacterium-surface interaction, particularly those resulting in adhesion or attachment, be they strong or weak, permanent or transient. This work takes a unique approach to identify a transient and reversible mode of bacterial attachment to a solid surface, by applying an electric field to exert a force for detachment. The force thus exerted proves to reach the amplitude required to detach bacteria of a pilus-less strain that weakly attach to a plastic surface. The method may be applied broadly to investigate bacteria-surface interaction.

Methods for Evaluating Attached Bacteria and Biofilms: An Overview

2003 ◽  
pp. 213-233 ◽  
Author(s):  
Gordon D. Christensen ◽  
W. Andrew Simpson ◽  
Jeffrey O. Anglen ◽  
Barry J. Gainor
Keyword(s):  
Attached Bacteria
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