Aerotaxis in Desulfovibrio

TY - JOUR

T1 - Aerotaxis in Desulfovibrio

AU - Wieland, Andrea Karin Eschemann

AU - Kühl, Michael

AU - Cypionka, H.

PY - 1999

Y1 - 1999

N2 - Aerotaxis of two sulphate-reducing bacteria, the freshwater strain Desulfovibrio desulfuricans CSN (DSM 9104) and the marine strain Desulfovibrio oxyclinae N13 (DSM 11498), was studied using capillary microslides, microscopy and oxygen microsensors. The bacteria formed ring-shaped bands in oxygen diffusion gradients surrounding O2 bubbles, which were placed into anoxic sulphate-free cell suspensions in capillary microslides. The radial expansion of the oxic volume by diffusion was stopped by aerobic respiration. Bands were formed by cells avoiding high O2 levels near the O2 bubble, as well as by cells entering from the surrounding anoxic zone. At the inner edge of the bands, O2 levels of up to 20% air saturation (50 µM O2) were found, while the outer edge always coincided with the oxic–anoxic interface. Ring diameters and O2 concentrations at the inner edge of the band depended on the cell density and the strain used in the suspension. Band formation did not occur in the absence of an electron donor (5 mM lactate) or when N2 gas bubbles were used. Both strains were highly motile with velocities of ˜ 32 µm s-1 during forward runs, and 7 µm s-1 during backward runs respectively. Within the bands, cells moved in circles of about 20 µm diameter, while cells outside the band exhibited straighter or only slightly bent traces. It is concluded that the capacity of respiration at high rates and the positive and negative aerotactical responses of Desulfovibrio provide an efficient strategy for removing O2 from the habitat in situations where sufficient electron donors and high cell densities are present.

AB - Aerotaxis of two sulphate-reducing bacteria, the freshwater strain Desulfovibrio desulfuricans CSN (DSM 9104) and the marine strain Desulfovibrio oxyclinae N13 (DSM 11498), was studied using capillary microslides, microscopy and oxygen microsensors. The bacteria formed ring-shaped bands in oxygen diffusion gradients surrounding O2 bubbles, which were placed into anoxic sulphate-free cell suspensions in capillary microslides. The radial expansion of the oxic volume by diffusion was stopped by aerobic respiration. Bands were formed by cells avoiding high O2 levels near the O2 bubble, as well as by cells entering from the surrounding anoxic zone. At the inner edge of the bands, O2 levels of up to 20% air saturation (50 µM O2) were found, while the outer edge always coincided with the oxic–anoxic interface. Ring diameters and O2 concentrations at the inner edge of the band depended on the cell density and the strain used in the suspension. Band formation did not occur in the absence of an electron donor (5 mM lactate) or when N2 gas bubbles were used. Both strains were highly motile with velocities of ˜ 32 µm s-1 during forward runs, and 7 µm s-1 during backward runs respectively. Within the bands, cells moved in circles of about 20 µm diameter, while cells outside the band exhibited straighter or only slightly bent traces. It is concluded that the capacity of respiration at high rates and the positive and negative aerotactical responses of Desulfovibrio provide an efficient strategy for removing O2 from the habitat in situations where sufficient electron donors and high cell densities are present.

U2 - 10.1046/j.1462-2920.1999.00057.x

DO - 10.1046/j.1462-2920.1999.00057.x

M3 - Journal article

SN - 1462-2912

VL - 1

SP - 489

EP - 494

JO - Environmental Microbiology

JF - Environmental Microbiology

IS - 6

ER -