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Bacterial Respiration and Growth Rates Affect the Feeding Preferences, Brood Size and Lifespan of Caenorhabditis elegans.

Yu L, Yan X, Ye C, Zhao H, Chen X, Hu F, Li H - PLoS ONE (2015)

Bottom Line: P. fluorescens Y1 and E. coli OP50 were found to be more active, with high respiration and rapid growth, whereas B. amyloliquefaciens JX1 and B. megaterium JX15 were inactive.The nematode C. elegans preferred active P. fluorescens Y1 and E. coli OP50 obviously.Nematodes generally require a balance between their preferred foods and beneficial foods, only preferred food may not be beneficial for nematodes.

View Article: PubMed Central - PubMed

Affiliation: Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.

ABSTRACT
Bacteria serve as live food and nutrients for bacterial-feeding nematodes (BFNs) in soils, and influence nematodes behavior and physiology through their metabolism. Five bacterial taxa (Bacillus amyloliquefaciens JX1, Variovorax sp. JX14, Bacillus megaterium JX15, Pseudomonas fluorescens Y1 and Escherichia coli OP50) and the typical BFN Caenorhabditis elegans were selected to study the effects of bacterial respiration and growth rates on the feeding preferences, brood size and lifespan of nematodes. P. fluorescens Y1 and E. coli OP50 were found to be more active, with high respiration and rapid growth, whereas B. amyloliquefaciens JX1 and B. megaterium JX15 were inactive. The nematode C. elegans preferred active P. fluorescens Y1 and E. coli OP50 obviously. Furthermore, worms that fed on these two active bacteria produced more offspring but had shorter lifespan, while inactive and less preferred bacteria had increased nematodes lifespan and decreased the brood size. Based on these results, we propose that the bacterial activity may influence the behavior and life traits of C. elegans in the following ways: (1) active bacteria reproduce rapidly and emit high levels of CO2 attracting C. elegans; (2) these active bacteria use more resources in the nematodes' gut to sustain their survival and reproduction, thereby reducing the worm's lifespan; (3) inactive bacteria may provide less food for worms than active bacteria, thus increasing nematodes lifespan but decreasing their fertility. Nematodes generally require a balance between their preferred foods and beneficial foods, only preferred food may not be beneficial for nematodes.

No MeSH data available.


Related in: MedlinePlus

Feeding preferences experiment.At time point 0, nematodes were placed in the center of the dish and the bacteria were placed on the surrounding circles; the dishes were then stored in the dark at 20°C. Over time, the worms moved away from the center and toward the bacterial zone (indicated by the five circles with dots) and non-bacterial zone (the remainder of the dish). The worms in the bacterial and non-bacterial zones were counted at 1, 2, 4, 8, 12, 24, 36, 48 hours.
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pone.0134401.g001: Feeding preferences experiment.At time point 0, nematodes were placed in the center of the dish and the bacteria were placed on the surrounding circles; the dishes were then stored in the dark at 20°C. Over time, the worms moved away from the center and toward the bacterial zone (indicated by the five circles with dots) and non-bacterial zone (the remainder of the dish). The worms in the bacterial and non-bacterial zones were counted at 1, 2, 4, 8, 12, 24, 36, 48 hours.

Mentions: This experiment was conducted to determine the preferences of C. elegans for different bacteria, using 90 mm diameter Petri dishes filled with NGM. Each dish was divided into five equal sections containing a 15-mm diameter dot-circle that was 20 mm from a center circle where the worms were placed (Fig 1). In each section, the dot-circle was defined as the ‘bacterial zone’, and the remainder of the section was defined as the ‘non-bacterial zone’. The five bacterial suspensions (20 μL) were randomly placed on the bacterial zone respectively. Approximate 1500 individual nematodes were placed on the center circle, with 10 replicates. All dishes were placed at random in a dark incubator at 20°C. The number of nematodes that migrated to each bacterial zone and non-bacterial zone was recorded at 1, 2, 4, 8, 12, 24, 36, and 48 hours under a stereomicroscope at 50 × magnification.


Bacterial Respiration and Growth Rates Affect the Feeding Preferences, Brood Size and Lifespan of Caenorhabditis elegans.

Yu L, Yan X, Ye C, Zhao H, Chen X, Hu F, Li H - PLoS ONE (2015)

Feeding preferences experiment.At time point 0, nematodes were placed in the center of the dish and the bacteria were placed on the surrounding circles; the dishes were then stored in the dark at 20°C. Over time, the worms moved away from the center and toward the bacterial zone (indicated by the five circles with dots) and non-bacterial zone (the remainder of the dish). The worms in the bacterial and non-bacterial zones were counted at 1, 2, 4, 8, 12, 24, 36, 48 hours.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519269&req=5

pone.0134401.g001: Feeding preferences experiment.At time point 0, nematodes were placed in the center of the dish and the bacteria were placed on the surrounding circles; the dishes were then stored in the dark at 20°C. Over time, the worms moved away from the center and toward the bacterial zone (indicated by the five circles with dots) and non-bacterial zone (the remainder of the dish). The worms in the bacterial and non-bacterial zones were counted at 1, 2, 4, 8, 12, 24, 36, 48 hours.
Mentions: This experiment was conducted to determine the preferences of C. elegans for different bacteria, using 90 mm diameter Petri dishes filled with NGM. Each dish was divided into five equal sections containing a 15-mm diameter dot-circle that was 20 mm from a center circle where the worms were placed (Fig 1). In each section, the dot-circle was defined as the ‘bacterial zone’, and the remainder of the section was defined as the ‘non-bacterial zone’. The five bacterial suspensions (20 μL) were randomly placed on the bacterial zone respectively. Approximate 1500 individual nematodes were placed on the center circle, with 10 replicates. All dishes were placed at random in a dark incubator at 20°C. The number of nematodes that migrated to each bacterial zone and non-bacterial zone was recorded at 1, 2, 4, 8, 12, 24, 36, and 48 hours under a stereomicroscope at 50 × magnification.

Bottom Line: P. fluorescens Y1 and E. coli OP50 were found to be more active, with high respiration and rapid growth, whereas B. amyloliquefaciens JX1 and B. megaterium JX15 were inactive.The nematode C. elegans preferred active P. fluorescens Y1 and E. coli OP50 obviously.Nematodes generally require a balance between their preferred foods and beneficial foods, only preferred food may not be beneficial for nematodes.

View Article: PubMed Central - PubMed

Affiliation: Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.

ABSTRACT
Bacteria serve as live food and nutrients for bacterial-feeding nematodes (BFNs) in soils, and influence nematodes behavior and physiology through their metabolism. Five bacterial taxa (Bacillus amyloliquefaciens JX1, Variovorax sp. JX14, Bacillus megaterium JX15, Pseudomonas fluorescens Y1 and Escherichia coli OP50) and the typical BFN Caenorhabditis elegans were selected to study the effects of bacterial respiration and growth rates on the feeding preferences, brood size and lifespan of nematodes. P. fluorescens Y1 and E. coli OP50 were found to be more active, with high respiration and rapid growth, whereas B. amyloliquefaciens JX1 and B. megaterium JX15 were inactive. The nematode C. elegans preferred active P. fluorescens Y1 and E. coli OP50 obviously. Furthermore, worms that fed on these two active bacteria produced more offspring but had shorter lifespan, while inactive and less preferred bacteria had increased nematodes lifespan and decreased the brood size. Based on these results, we propose that the bacterial activity may influence the behavior and life traits of C. elegans in the following ways: (1) active bacteria reproduce rapidly and emit high levels of CO2 attracting C. elegans; (2) these active bacteria use more resources in the nematodes' gut to sustain their survival and reproduction, thereby reducing the worm's lifespan; (3) inactive bacteria may provide less food for worms than active bacteria, thus increasing nematodes lifespan but decreasing their fertility. Nematodes generally require a balance between their preferred foods and beneficial foods, only preferred food may not be beneficial for nematodes.

No MeSH data available.


Related in: MedlinePlus