Seasonal dynamics of bacterial assemblages in epilithic biofilms in a northeastern Ohio stream

Olapade, Ola A.; Leff, Laura Gunn

doi:10.1899/0887-3593(2004)023<0686:sdobai>2.0.co;2

Cited by 28 publications

(32 citation statements)

References 66 publications

(5 reference statements)

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“…Among these bacterial groups, bacteria belonging to the ␤-Proteobacteria generally predominated; this finding is consistent with the results of previous studies that showed that there were high proportions of ␤-Proteobacteria in aquatic biofilms (5,22,32). Although bacteria belonging to the ␦-Proteobacteria accounted for the lowest proportion of sequences in our study, a high number of bacterial species with the ability to reduce sulfate belong to this subdivision and have been found previously in bacterial biofilms in other studies (31,34).…”

Section: Discussionsupporting

confidence: 93%

Microbial Communities and Fecal Indicator Bacteria Associated with Cladophora Mats on Beach Sites along Lake Michigan Shores

Olapade

Depas

Jensen

et al. 2006

Appl Environ Microbiol

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A high biomasses of Cladophora, a filamentous green alga, is found mainly during the summer along the shores of Lake Michigan. In this study, the abundance and persistence of the fecal indicator bacterium Escherichia coli and sulfate-reducing bacteria (SRB) on Cladophora mats collected at Lake Michigan beaches were evaluated using both culture-based and molecular analyses. Additionally, 16S rRNA gene cloning and sequencing were used to examine the bacterial community composition. Overall, E. coli was detected in all 63 samples obtained from 11 sites, and the average levels at most beaches ranged from 2,700 CFU/100 g (wet weight) of Cladophora to 7,500 CFU/100 g of Cladophora. However, three beaches were found to have site average E. coli densities of 12,800, 21,130, and 27,950 CFU/100 g of Cladophora. The E. coli levels in the lake water collected at the same time from these three sites were less than the recommended U.S. Environmental Protection Agency limit, 235 CFU/100 ml. E. coli also persisted on Cladophora mats in microcosms at room temperature for more than 7 days, and in some experiments it persisted for as long as 28 days. The SRB densities on Cladophora mats were relatively high, ranging from 4.4 ؋ 10 6 cells/g (6.64 log CFU/g) to 5.73 ؋ 10 6 cells/g (6.76 log CFU/g) and accounting for between 20% and 27% of the total bacterial counts. Partial sequences of the 16S rRNA gene clones revealed a phylogenetically diverse community, in which the CytophagaFlavobacterium-Bacteroides cluster and the low-G؉C-content gram-positive bacteria were the dominant organisms, accounting for 40% and 12.8%, respectively, of the total clone library. These results further reveal the potential public health and ecological significance of Cladophora mats that are commonly found along the shoreline of Lake Michigan, especially with regard to the potential to harbor microorganisms associated with fecal pollution and odor-causing bacteria.

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Section: Discussionsupporting

confidence: 93%

Microbial Communities and Fecal Indicator Bacteria Associated with Cladophora Mats on Beach Sites along Lake Michigan Shores

Olapade

Depas

Jensen

et al. 2006

Appl Environ Microbiol

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“…S1, S2, and S3 in the supplemental material). Seasonal fluctuations of prokaryotic biofilm inhabitants were also found in various other rivers and studies and were usually correlated with temperature and other abiotic environmental variables (8,36,46). We can support this conclusion with the present study.…”

Section: Figsupporting

confidence: 91%

Seasonal and Successional Influences on Bacterial Community Composition Exceed That of Protozoan Grazing in River Biofilms

Wey

Jürgens

Weitere

2012

Appl Environ Microbiol

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The effects of protozoa (heterotrophic flagellates and ciliates) on the morphology and community composition of bacterial biofilms were tested under natural background conditions by applying size fractionation in a river bypass system. Confocal laser scanning microscopy (CLSM) was used to monitor the morphological structure of the biofilm, and fingerprinting methods (single-stranded conformation polymorphism [SSCP] and denaturing gradient gel electrophoresis [DGGE]) were utilized to assess changes in bacterial community composition. Season and internal population dynamics had a greater influence on the bacterial biofilm than the presence of protozoa. Within this general framework, bacterial area coverage and microcolony abundance were nevertheless enhanced by the presence of ciliates (but not by the presence of flagellates). We also found that the richness of bacterial operational taxonomic units was much higher in planktonic founder communities than in the ones establishing the biofilm. Within the first 2 h of colonization of an empty substrate by bacteria, the presence of flagellates additionally altered their biofilm community composition. As the biofilms matured, the number of bacterial operational taxonomic units increased when flagellates were present in high abundances. The additional presence of ciliates tended to at first reduce (days 2 to 7) and later increase (days 14 to 29) bacterial operational taxonomic unit richness. Altogether, the response of the bacterial community to protozoan grazing pressure was small compared to that reported in planktonic studies, but our findings contradict the assumption of a general grazing resistance of bacterial biofilms toward protozoa.

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“…Similarly, results based on FISH revealed the same pattern in the representation of all the major bacterial taxa examined, with members of the -Proteobacteria subclass accounting for the largest fraction (20%) within the epiphytic assemblages on both plants. Even though this particular result may contradict some earlier similar studies that generally reported instead the relative dominance of both -and -Proteobacteria subclasses in freshwater environments (e.g., Araya et al 2003;McNamara and Leff 2004;Olapade and Leff 2004), -Proteobacteria also represent a larger percentage of the bacteria on leaves prior to senescence and before entering the stream (McNamara and Leff 2004). Most importantly, the high occurrence of -Proteobacteria as well as populations of E. coli and E. faecalis observed on the two plants may further validate earlier studies that suggested the potential for aquatic vegetation to harbor and support fecal indicator and pathogenic bacterial populations in aquatic systems (Whitman et al 2003(Whitman et al , 2005Weage 2010).…”

Section: Discussioncontrasting

confidence: 50%

“…The probe sequences and respective hybridization conditions employed are described in Olapade and Leff (2004). Briefly, bacterial cells in the preserved water samples were concentrated onto 0.2 mm pore-size anodisc or polycarbonate filters (Whatman, Maidstone, UK) and then rinsed with deionized water, treated with 1 mL 0.1% Nonidet P-40 (Sigma-Aldrich, St. Louis, Missouri).…”

Section: Bacterial Enumerationmentioning

confidence: 99%

Occurrence and diversity of epiphytic bacterial communities on two native plant species in a Michigan Creek

Olapade

Pung

Goldman

et al. 2011

Journal of Freshwater Ecology

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We examined the occurrence and diversity of bacteria of different phylogenetic groups in epiphytic assemblages on two native Michigan plant species mayapple (Podophyllum peltatum) and cow parsnip (Heracleum maximum) when the plant leaves were submerged in fresh water. Fresh leaves were incubated in triplicate for about a week within a creek in Hasting, Michigan, and in laboratory microcosm to develop mature epiphytic assemblages. We enumerated bacteria in these assemblages by nucleic acid staining (i.e., total direct counts using 4 0 ,6-diamidino-2-phenyllindole) and fluorescent in situ hybridization (FISH), while community diversity was determined based on 16S rRNA gene sequencing. FISH indicated the dominance of members of the -Proteobacterial subclass (20%) on both plant species, while the 16S rRNA gene analysis revealed the predominance of the -Proteobacteria (51%) on mayapple and the Fermicutes (26%) on cow parsnip, with the Bacteroidetes present equally within the epiphytic assemblages on both plants.

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Seasonal dynamics of bacterial assemblages in epilithic biofilms in a northeastern Ohio stream

Cited by 28 publications

References 66 publications

Microbial Communities and Fecal Indicator Bacteria Associated with Cladophora Mats on Beach Sites along Lake Michigan Shores

Microbial Communities and Fecal Indicator Bacteria Associated with Cladophora Mats on Beach Sites along Lake Michigan Shores

Seasonal and Successional Influences on Bacterial Community Composition Exceed That of Protozoan Grazing in River Biofilms

Occurrence and diversity of epiphytic bacterial communities on two native plant species in a Michigan Creek

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