The effect of substrate shock on populations of starving aquatic bacteria

Straškrabová, Vêra

doi:10.1111/j.1365-2672.1983.tb02610.x

Cited by 22 publications

(20 citation statements)

References 20 publications

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“…Small inoculum sizes, as in our study, have even been shown to increase viable counts (13). Substrate shock caused by high substrate concentrations (42,46) has often been blamed for poor culturability. In fact, low substrate concentrations have been shown to improve cultivation success (10,13,25,43,45,56).…”

Section: Discussionmentioning

confidence: 78%

“…The microorganisms remain in their habitual surroundings, and due to the diffusion from the bottom of the tube, substrate concentrations increase only slowly. This helps to avoid a substrate shock (46) but still supplies enough substrate to sustain visible growth.…”

mentioning

confidence: 99%

“…As an alternative enrichment technique, undisturbed sediment sections were placed in substrate gradients and were used for enrichment and isolation of microorganisms as well. This approach should help to avoid the potential substrate shock (46) and minimize disturbance during sampling.…”

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confidence: 99%

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Microbial Diversity in Coastal Subsurface Sediments: a Cultivation Approach Using Various Electron Acceptors and Substrate Gradients

Köpke

Wilms

Engelen

et al. 2005

Appl Environ Microbiol

175

120

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Microbial communities in coastal subsurface sediments are scarcely investigated and have escaped attention so far. But since they are likely to play an important role in biogeochemical cycles, knowledge of their composition and ecological adaptations is important. Microbial communities in tidal sediments were investigated along the geochemical gradients from the surface down to a depth of 5.5 m. Most-probable-number (MPN) series were prepared with a variety of different carbon substrates, each at a low concentration, in combination with different electron acceptors such as iron and manganese oxides. These achieved remarkably high cultivation efficiencies (up to 23% of the total cell counts) along the upper 200 cm. In the deeper sediment layers, MPN counts dropped significantly. Parallel to the liquid enrichment cultures in the MPN series, gradient cultures with embedded sediment subcores were prepared as an additional enrichment approach. In total, 112 pure cultures were isolated; they could be grouped into 53 different operational taxonomic units (OTU). The isolates belonged to the Proteobacteria, "Bacteroidetes," "Fusobacteria," Actinobacteria, and "Firmicutes." Each cultivation approach yielded a specific set of isolates that in general were restricted to this single isolation procedure. Analysis of the enrichment cultures by PCR and denaturing gradient gel electrophoresis revealed an even higher diversity in the primary enrichments that was only partially reflected by the culture collection. The majority of the isolates grew well under anoxic conditions, by fermentation, or by anaerobic respiration with nitrate, sulfate, ferrihydrite, or manganese oxides as electron acceptors.

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Section: Discussionmentioning

confidence: 78%

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confidence: 99%

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Microbial Diversity in Coastal Subsurface Sediments: a Cultivation Approach Using Various Electron Acceptors and Substrate Gradients

Köpke

Wilms

Engelen

et al. 2005

Appl Environ Microbiol

175

120

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“…The identification and quantification of such "r-strategists" within heterotrophic picoplankton assemblages might thus eventually allow deductions about short-term fluctuations in the availability of organic matter in aquatic habitats, e.g., for a biological monitoring of pollution effects. In contrast, many if not most of the typical free-living marine and freshwater bacteria appear to lack the ability to form colonies on solid media (282), and their growth is negatively affected by enhanced substrate levels (289).…”

Section: Patchiness and Gradientsmentioning

confidence: 99%

Fate of Heterotrophic Microbes in Pelagic Habitats: Focus on Populations

Pernthaler

Amann

2005

Microbiol Mol Biol Rev

140

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Major biogeochemical processes in the water columns of lakes and oceans are related to the activities of heterotrophic microbes, e.g., the mineralization of organic carbon from photosynthesis and allochthonous influx or its transport to the higher trophic levels. During the last 15 years, cultivation-independent molecular techniques have substantially contributed to our understanding of the diversity of the microbial communities in different aquatic systems. In parallel, the complexity of aquatic habitats at a microscale has inspired research on the ecophysiological properties of uncultured microorganisms that thrive in a continuum of dissolved to particulate organic matter. One possibility to link these two aspects is to adopt a “Gleasonian” perspective, i.e., to study aquatic microbial assemblages in situ at the population level rather than looking at microbial community structure, diversity, or function as a whole. This review compiles current knowledge about the role and fate of different populations of heterotrophic picoplankton in marine and inland waters. Specifically, we focus on a growing suite of techniques that link the analysis of bacterial identity with growth, morphology, and various physiological activities at the level of single cells. An overview is given of the potential and limitations of methodological approaches, and factors that might control the population sizes of different microbes in pelagic habitats are discussed

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“…This was seen with each continuous culture assessed by colony counts on agar media. Changes in strain characteristics leading to reduced colony size, or even complete loss of ability to grow, following transfer from continuous culture to media with relatively high substrate concentrations have been observed by others (Postgate & Hunter, 1964;StraSkbova, 1983 ;Hofle, 1983), but the physiological mechanisms underlying these observations have not been elucidated. At no time did the reduction in colony size make it difficult to distinguish between colonies of strains B6/2 and DT26 on media YMGA and GA after 4 d .…”

Section: 05mentioning

confidence: 99%

Competition between Specialist and Generalist Methylotrophic Bacteria for an Intermittent Supply of Methylamine

1987

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A us t ralia (Received I9 June I986 ; revised 23 October 1986)A computer program, METHCOMP, to simulate the competition between an obligately methylotrophic bacterium, a facultatively methylotrophic bacterium, a bacterium able to use methylamine as nitrogen source only, and a non-methylamine-using bacterium for methylamine and glucose in continuous culture with a constant or alternating nutrient supply is described. Competitions between obligate methylotroph B6/2 and facultative methylotroph DT26 in continuous cultures supplied alternately with methylamine and glucose/ammonium were both simulated using experimentally determined growth parameters and investigated in laboratory mixed cultures. The results of the laboratory experiments were in excellent agreement with the simulations. The composition of the mixed population is predicted to vary with imposed dilution rate, with strain B6/2 excluded at dilution rates below 0.0625 h-l and strain DT26 excluded at dilution rates above 0.20 h-l. At intermediate dilution rates both strains coexisted in stable proportions which depended upon the dilution rate. Hence, the use of an alternating nutrient supply may offer a practical approach to the control of the composition of defined, mixed microbial populations. I N T R O D U C T I O NMixed microbial populations are the rule in many traditional food and drink fermentations but have been little exploited otherwise, in spite of potential advantages over axenic cultures, such as higher growth rate, higher yield, and greater stability (Harrison, 1978;Larsen et al., 1978). The development of new mixed culture processes is hampered by the absence of rational techniques for culture formulation and for controlling culture composition.One major aim of this work was to develop an experimental model system to study means of controlling the composition of mixed cultures by alternating the supply of two nutrients so as to favour each of two coexisting bacteria in turn. The system examined was based upon bacterial competition for methylamine, with glucose as the alternating nutrient. The second major aim of the work was to test certain hypotheses about the ecology of methylamine-using bacteria.Bacteria able to use methylamine under aerobic conditions include at least three main physiological types, namely (a) specialist, obligately methylotrophic bacteria able to use methylamine but not non-C, compounds as sole carbon and energy source; (6) generalist, facultative methylotrophs able to use methylamine or other compounds singly as sole carbon and energy source; and (c) methazotrophs which cannot use methylamine as sole carbon and energy source but, in the presence of another source of carbon and energy, can use it as sole nitrogen source. The existence of the methazotrophs adds an extra dimension to the model not possible

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The effect of substrate shock on populations of starving aquatic bacteria

Cited by 22 publications

References 20 publications

Microbial Diversity in Coastal Subsurface Sediments: a Cultivation Approach Using Various Electron Acceptors and Substrate Gradients

Microbial Diversity in Coastal Subsurface Sediments: a Cultivation Approach Using Various Electron Acceptors and Substrate Gradients

Fate of Heterotrophic Microbes in Pelagic Habitats: Focus on Populations

Competition between Specialist and Generalist Methylotrophic Bacteria for an Intermittent Supply of Methylamine

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