Analysis of Actively Metabolizing Bacterial Populations with the Autoradiographic Method

Höppe, Henning A.

doi:10.1007/978-3-642-66791-6_14

Cited by 36 publications

(14 citation statements)

References 14 publications

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“…Amongst the most commonly used of these methodologies has been the enumeration of numbers of actively respiring cells, identified by the reduction of the fluorogenic tetrazolium dye CTC (Rodriguez et al 1992), the enumeration of nucleoidcontaining cells (NUCC) (Zweifel & Hagström 1995), and microautoradiography (Hoppe 1976). These techniques, among several others (Choi et al 1996, Yamaguchi & Nasu 1997, Williams et al 1998, Gasol et al 1999), probe different physiological or morphological cell features to assess states of cell activity.…”

Section: Measuring Bacterial Activitymentioning

confidence: 99%

Microscale heterogeneity in the activity of coastal bacterioplankton communities

Seymour¹,

Mitchell²,

Seuront³

2004

Aquat. Microb. Ecol.

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Microscale sampling techniques and flow cytometry were employed to measure the distribution patterns of 8 subpopulations of bacteria separated according to variations in cell fluorescence and light scatter properties. Subpopulations of bacteria defined on the basis of these parameters have recently been shown to represent cells exhibiting dissimilar activity levels, and we therefore assume that the subpopulations of bacteria identified here represent metabolically diverse groups. Microscale distribution patterns of these subpopulations were measured at a resolution of 4.5 and 12 mm, within 2 dissimilar coastal habitats. A mean 2-fold change in the abundance of the total bacterial community across sample sets was observed. However, levels of spatial heterogeneity were consistently higher for the cytometrically defined subpopulations than total counts. In most samples, the population of bacteria exhibiting the highest levels of green fluorescence, or DNA content, and hence assumed to represent the most active bacteria in the community, also showed the highest levels of microscale spatial variability, with a maximum change in abundance of 14.5-fold observed across a distance of 9 mm. Where Zipf rank-size analysis was conducted, the microscale distributions of subpopulations differed significantly (p < 0.05) in 79% of cases, implying that bacterial communities are made up of physiologically distinct compartments, perhaps influenced by different microscale features of the environment. We suggest that these results provide the first evidence for the existence of microscale heterogeneity in the metabolic activity of aquatic bacterial communities. KEY WORDS: Marine bacteria · Microscale heterogeneity · Flow cytometry · Single cell activity Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 35: [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] 2004 Microscale patchiness in the abundance of bacterioplankton communities has indeed been observed across distances of centimetres (Mitchell & Fuhrman 1989, Duarte & Vaqué 1992, millimetres (Seymour et al. 2000) and micrometres (Krembs et al. 1998). Recently, Long & Azam (2001) also identified millimetre-scale heterogeneity in the species richness of bacterioplankton communities, indicating that microscale variability in bacterioplankton community composition may sometimes exceed the levels of phylogenetic variability observed at large scales (Riemann et al. 1999, Riemann & Middelboe 2002. They attributed these microscale changes in community composition to bacterial interactions with specific microhabitats associated with particulate organic matter . Microscale variability in bacterial growth and activity is also anticipated to occur in response to heterogeneities in the distribution of organic material in the ocean (Azam 1998, Kiørboe & Jackson 2001. However, while coherent shifts in the activity of bacterioplankton communities have been widely observed across larger scales (del Giorgio & Scarborough 1995, del Gio...

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Section: Measuring Bacterial Activitymentioning

confidence: 99%

Microscale heterogeneity in the activity of coastal bacterioplankton communities

Seymour¹,

Mitchell²,

Seuront³

2004

Aquat. Microb. Ecol.

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“…The resulting Spots on the film were counted under the microscope at a 630 to 1000-fold magnification. A comprehensive description of these procedures is offered by Hoppe (1977).…”

Section: Number Of Active Bacteriamentioning

confidence: 99%

Investigations on the Influence of Coastal Upwelling and Polluted Rivers on the Microflora of the Northeastern Atlantic off Portugal. II. Activity and Biomass Production of the Bacterial Population

Gocke¹,

Hoppe²,

Bauerfeind³

1983

Botanica Marina

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During May 1981 the following parameters were measured in the sea area off the west and south coast of Portugal: concentration of monosaccharides, number of actively metabolizing bacteria, maximum uptake velocity and turnover rate of glucose, specific activity rate of the microbial population and bacterial production. A good correlation between the activity parameters was found in all water samples. Highest values of bacterial activity were measured in the region off the mouth of the Tejo River. Apart from this eutrophied area high bacterial activity was detected in the offshore region of the northern part of the study area (off Porto) and in the nearshore region of the Algarve coast, where aged upwelled water nasses were encountered. A sharp decrease was found with increasing depth, where at 100 m and deeper the activity parameters and the number of active bacteria sometimes dropped below the detection limit. The concentration of monosaccharides did not reflect these strong regional and vertical differences.

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“…Microautoradiography (Hoppe 1977) revealed that a broad diversity of grazers ingest and effectively metabolize the cyanobacteria (Fig.4). Protozoa, primarily, show effective metabolic utilization of cyanobacteria as a food source as indicated by the uniform distribution of the exposed silver grains in the microautoradiographs.…”

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Chroococcoid cyanobacteria: a significant component in the food web dynamics of the open ocean

Iturriaga¹,

Mitchell²

1986

Mar. Ecol. Prog. Ser.

143

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New techniques used during a recent study in the oligotrophic North Pacific Ocean demonstrated that coccoid cyanobacteria were the most abundant photoautotrophs. Despite their small size, they accounted for 64 % of the total photosynthesis, with specific growth rates of 1.6 d-'. Grazing experiments indicated that a diverse assemblage of micrograzers is able to consume and effectively metabolize chroococcoid cyanobacteria. In the open ocean, a significant trophic interaction occurs between cyanobacteria and micrograzers, components not included in the classical paradigm of the oceanic food web.In oligotrophic ocean systems, picoplankton (Sieburth et al. 1978) account for approximately 60 % of the inorganic carbon fixation (Li et al. 1983 and apparently have high specific growth rates , Douglas 1984, Landry et al. 1984. Chroococcoid cyanobacteria have been observed in the marine environment (Johnson & Sieburth 1979, Waterbury et al. 1979), but only recently have they been implicated as a substantial component of the autotrophic picoplankton. Information about cyanobacteria in situ growth rates, photosynthetic characteristics and contribution to higher trophic levels is still limited. Studies conducted with cultures of Synechococcus sp. demonstrated net specific growth rates of u p to 1.5 d-', saturating at low irradiance (Morris & Glover 1981). Preliminary field data indicate that picoplankton photosynthesis saturates at low irradiance, with maximal contributions to primary production at the base of the euphotic zone (Morris & Glover 1981, Li et al. 1983). However, the relative contribution of cyanobacteria to total photosynthesis has not been quantified. Few studies have investigated the cya- demonstrated their suitability as food for micrograzers, while ingestion, but not digestion, by calanoid copepods has been observed (Johnson et al. 1982).In the North Pacific gyre (35"N, 128"W), we studied the distribution and photosynthesis of cyanobacteria and their consumption by micrograzers. This region is typical of the oligotrophic subtropical open ocean in spring, with a mixed layer of 60 to 80 m, and a deep chlorophyll maximum between 90 and 105 m as shown by in situ profiles of density, fluorescence, and beam attenuation (Fig. 1). Integrated euphotic zone chlorophyll a was approximately 25 mg m-2. Fig. 2 illustrates the vertical distribution of cyanobacteria and acetone extracted chlorophyll a concentrations for discrete samples at the study site. Daily specific growth and grazing rates were calculated from the general exponential relation:where N, = concentration at time t; No = concentration at time zero; r = specific rate coefficient; t = time. References to rates in this paper are specific natural log rates as defined above. If the cyanobacteria population is in steady state, the specific rate constants for growth, U , grazing, g, and residual losses, 1, satisfy the equation: r = U -g -1 = 0. For our experiments, the loss term, 1, includes respiration and exudation by cyanobacteria, respiration and e...

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Analysis of Actively Metabolizing Bacterial Populations with the Autoradiographic Method

Cited by 36 publications

References 14 publications

Microscale heterogeneity in the activity of coastal bacterioplankton communities

Microscale heterogeneity in the activity of coastal bacterioplankton communities

Investigations on the Influence of Coastal Upwelling and Polluted Rivers on the Microflora of the Northeastern Atlantic off Portugal. II. Activity and Biomass Production of the Bacterial Population

Chroococcoid cyanobacteria: a significant component in the food web dynamics of the open ocean

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