Detection of Bacterial Endospores in Soil by Terbium Fluorescence

Ammann, Andrea Brandes; Kölle, Linda; Brandl, Helmut

doi:10.1155/2011/435281

Cited by 25 publications

(21 citation statements)

References 25 publications

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“…The detailed protocol is available in Supporting Information Appendix S1. Endospore numbers were estimated by quantification of dipicolinic acid (DPA) and estimation based on known DPA concentrations in endospores (Brandes Ammann et al ., ).…”

Section: Resultsmentioning

confidence: 97%

Endospore‐enriched sequencing approach reveals unprecedented diversity of Firmicutes in sediments

Wunderlin

Junier

Roussel-Delif

et al. 2014

Environ Microbiol Rep

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We present a method for the physical isolation of endospores from environmental samples allowing the specific targeting of endospore-forming bacteria for sequencing (endospore-enriched community). The efficiency of the method was tested on lake sediment samples. After 16S rRNA gene amplicon sequencing, the composition in the endospore-enriched community was compared with the community from untreated control samples (whole community). In the whole community, Firmicutes had a relative abundance of 8% and 19% in the two different lake sediments. In contrast, in the endospore-enriched community, Firmicutes abundance increased to 90.6% and 83.9%, respectively, confirming the efficiency of the endospore enrichment. The relative abundance of other microbial groups that form spore-like resisting states (i.e. actinobacteria, cyanobacteria and myxococcales) was below 2% in the endospore-enriched community, indicating that the method is adapted to true endospores. Representatives from two out of the three known classes of Firmicutes (Bacilli and Clostridia) were detected and supposedly asporogenic groups (e.g. Ethanoligenes and Trichococcus) could be detected. The method presented here is a leap forward for ecological studies of endospore-forming Firmicutes. It can be applied to other types of samples in order to reveal the diversity and metabolic potential of this bacterial group in the environment.

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Section: Resultsmentioning

confidence: 97%

Endospore‐enriched sequencing approach reveals unprecedented diversity of Firmicutes in sediments

Wunderlin

Junier

Roussel-Delif

et al. 2014

Environ Microbiol Rep

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“…Specifically, a relatively high frequency may enhance the population’s ability to take advantage of favorable growth conditions, but it also renders the population sensitive to growth-inhibiting conditions. The relatively low rate of spontaneous germination that we measure under our experimental conditions (Figure 1C; ~10 4 /day) would allow a population of 10 9 spores (as can be found in 1 g soil [32]) to last for >100 years before exhaustion. A population of dormant cells could therefore regularly assess the environment for long periods of time, thereby promoting survival of the population during extended periods of austerity and contributing to microbial diversity [33].…”

Section: Discussionmentioning

confidence: 99%

Phenotypic Diversity as a Mechanism to Exit Cellular Dormancy

Sturm

Dworkin

2015

Current Biology

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SUMMARY Microorganisms can facilitate their survival in stressful environments by entering a state of metabolic inactivity or dormancy [1]. However, this state impairs the function of the very sensory systems necessary to detect favorable growth conditions. Thus, how can a metabolically quiescent cell accurately monitor environmental conditions in order to best decide when to exit dormancy? One strategy employed by microbes to deal with changing environments is the generation of phenotypes that may be less well adapted to a current condition but might confer an advantage in the future [2, 3]. This bet-hedging depends on phenotypic diversity in the population [4], which itself can derive from naturally occurring stochastic differences in gene expression [5, 6]. In the case of metabolic dormancy, a bet-hedging strategy that has been proposed is the “scout model” where cells comprising a fraction of the dormant population reinitiate growth stochastically, independent of environmental cues [7, 8]. Here, we provide experimental evidence that such a mechanism exists in dormant spores produced by the ubiquitous soil bacterium Bacillus subtilis. We observe that these spores reinitiate growth at a low but measureable frequency even in the absence of an inducing signal. This phenomenon is the result of phenotypic variation in the propensity of individual spores to reinitiate growth spontaneously. Since this bet-hedging mechanism produces individuals that will either grow under favorable conditions or die under unfavorable conditions, a population can properly respond to environmental changes despite the impaired sensory ability of individual cells.

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“…Dipicolinic acid concentration was measured using a terbium complexation method (Rosen et al, 1997; Ammann et al, 2011). The calibration curve was prepared using three different concentrations of DPA (0.005, 0.05, and 0.5 μM) in sterile milli-Q water and TbCl 3 at a final concentration of 30 μM.…”

Section: Methodsmentioning

confidence: 99%

Variability in DPA and Calcium Content in the Spores of Clostridium Species

et al. 2016

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Spores of a number of clostridial species, and their resistance to thermal treatment is a major concern for the food industry. Spore resistance to wet heat is related to the level of spore hydration, which is inversely correlated with the content of calcium and dipicolinic acid (DPA) in the spore core. It is widely believed that the accumulation of DPA and calcium in the spore core is a fundamental component of the sporulation process for all endospore forming species. We have noticed heterogeneity in the heat resistance capacity and overall DPA/calcium content among the spores of several species belonging to Clostridium sensu stricto group: two C. acetobutylicum strains (DSM 792 and 1731), two C. beijerinckii strains (DSM 791 and NCIMB 8052), and a C. collagenovorans strain (DSM 3089). A C. beijerinckii strain (DSM 791) and a C. acetobutylicum strain (DSM 792) display low Ca and DPA levels. In addition, these two species, with the lowest average Ca/DPA content amongst the strains considered, also exhibit minimal heat resistance. There appears to be no correlation between the Ca/DPA content and the phylogenetic distribution of the C. acetobutylicum and C. beijerinckii species based either on the 16S rRNA or the spoVA gene. This finding suggests that a subset of Clostridium sensu stricto species produce spores with low resistance to wet heat. Additionally, analysis of individual spores using STEM-EDS and STXM revealed that DPA and calcium levels can also vary amongst individual spores in a single spore population.

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Detection of Bacterial Endospores in Soil by Terbium Fluorescence

Cited by 25 publications

References 25 publications

Endospore‐enriched sequencing approach reveals unprecedented diversity of Firmicutes in sediments

Endospore‐enriched sequencing approach reveals unprecedented diversity of Firmicutes in sediments

Phenotypic Diversity as a Mechanism to Exit Cellular Dormancy

Variability in DPA and Calcium Content in the Spores of Clostridium Species

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