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Entrapment of ciliates at the water-air interface.

Ferracci J, Ueno H, Numayama-Tsuruta K, Imai Y, Yamaguchi T, Ishikawa T - PLoS ONE (2013)

Bottom Line: We first characterized the behavior of cells at the interface and showed that the cells' swimming velocity was considerably reduced at the WAI.Even though the taxes were still effective, the entrapment phenomenon was not dependent on the physiological conditions, but was instead affected by the physical properties at the interface.This knowledge is useful for a better understanding of the physiology of microorganisms at interfaces in nature and in industry.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering, Tohoku University, Sendai, Japan.

ABSTRACT
The importance of water-air interfaces (WAI) on microorganism activities has been recognized by many researchers. In this paper, we report a novel phenomenon: the entrapment of ciliates Tetrahymena at the WAI. We first characterized the behavior of cells at the interface and showed that the cells' swimming velocity was considerably reduced at the WAI. To verify the possible causes of the entrapment, we investigated the effects of positive chemotaxis for oxygen, negative geotaxis and surface properties. Even though the taxes were still effective, the entrapment phenomenon was not dependent on the physiological conditions, but was instead affected by the physical properties at the interface. This knowledge is useful for a better understanding of the physiology of microorganisms at interfaces in nature and in industry.

Show MeSH
Behavior of cells under three different physiological conditions at day 5 (for six different samples): (A) set-up, (B) surface concentration, and (C) swimming velocity.
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pone-0075238-g003: Behavior of cells under three different physiological conditions at day 5 (for six different samples): (A) set-up, (B) surface concentration, and (C) swimming velocity.

Mentions: To begin, we considered two possible biological causes: positive aerotaxis and negative geotaxis. This allowed us to determine if entrapment was a possible cause, or if a strong attraction phenomenon caused the cells to stay at the interface and to swim in two dimensions as if trapped. To evaluate the effect of these two taxes, three successive experiments were conducted, as shown in Fig. 3(A). We first observed the cells' behavior in the control setting, then turned the pool upside-down to see the effect of geotaxis, and finally returned it to its original position. Mineral oil was then added to the top to see the effect of aerotaxis. The upside-down condition was observed with an inverted microscope (Olympus IX71, Japan). An 8-mm-diameter pool, instead of the 25-mm-diameter pool, was used to keep the upside down condition stable. This set of experiments was performed on day 5. The swimming velocity of the cells was measured in the diluted suspension to avoid cell-cell interactions.


Entrapment of ciliates at the water-air interface.

Ferracci J, Ueno H, Numayama-Tsuruta K, Imai Y, Yamaguchi T, Ishikawa T - PLoS ONE (2013)

Behavior of cells under three different physiological conditions at day 5 (for six different samples): (A) set-up, (B) surface concentration, and (C) swimming velocity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3794946&req=5

pone-0075238-g003: Behavior of cells under three different physiological conditions at day 5 (for six different samples): (A) set-up, (B) surface concentration, and (C) swimming velocity.
Mentions: To begin, we considered two possible biological causes: positive aerotaxis and negative geotaxis. This allowed us to determine if entrapment was a possible cause, or if a strong attraction phenomenon caused the cells to stay at the interface and to swim in two dimensions as if trapped. To evaluate the effect of these two taxes, three successive experiments were conducted, as shown in Fig. 3(A). We first observed the cells' behavior in the control setting, then turned the pool upside-down to see the effect of geotaxis, and finally returned it to its original position. Mineral oil was then added to the top to see the effect of aerotaxis. The upside-down condition was observed with an inverted microscope (Olympus IX71, Japan). An 8-mm-diameter pool, instead of the 25-mm-diameter pool, was used to keep the upside down condition stable. This set of experiments was performed on day 5. The swimming velocity of the cells was measured in the diluted suspension to avoid cell-cell interactions.

Bottom Line: We first characterized the behavior of cells at the interface and showed that the cells' swimming velocity was considerably reduced at the WAI.Even though the taxes were still effective, the entrapment phenomenon was not dependent on the physiological conditions, but was instead affected by the physical properties at the interface.This knowledge is useful for a better understanding of the physiology of microorganisms at interfaces in nature and in industry.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering, Tohoku University, Sendai, Japan.

ABSTRACT
The importance of water-air interfaces (WAI) on microorganism activities has been recognized by many researchers. In this paper, we report a novel phenomenon: the entrapment of ciliates Tetrahymena at the WAI. We first characterized the behavior of cells at the interface and showed that the cells' swimming velocity was considerably reduced at the WAI. To verify the possible causes of the entrapment, we investigated the effects of positive chemotaxis for oxygen, negative geotaxis and surface properties. Even though the taxes were still effective, the entrapment phenomenon was not dependent on the physiological conditions, but was instead affected by the physical properties at the interface. This knowledge is useful for a better understanding of the physiology of microorganisms at interfaces in nature and in industry.

Show MeSH