TABLE 3.
Evidence that uncultured, large, marine sulfur bacteria (Beggiatoa spp., Thioploca spp., Thiomargarita namibiensis, and attached filaments from White Point hydrothermal vents) are vacuolate and tabulation of internal nitrate concentrations
| Site and bacteriumb | Filament width (μm) | Vacuole present? | Presence/absence of central vacuole supported by: | Intracellular nitrate concn | Reference(s) or source | ||
| EMc | Protein/biovolume (mg of protein/cm3) | ||||||
| Narrow-filament controlaBeggiatoa sp. strains | |||||||
| MS-81-6 | 4 | No | Yes | 121 ± 17i | <0.3 μM | 20 | |
| MS-81-1c | 2 | No | Yes | ND | ND | 20 | |
| White Point, Calif., HTV; attached filaments | 4-112d | Yes | NDe | 7.6 ± 0.8 | Not detectedf (n = 2) | This study | |
| Carmel Canyon; Beggiatoa sp. | 20-76 | Yes | ND | 8.9 ± 1.1 | 16.6 ± 4 mM (n = 2) | This study | |
| Monterey Canyon; Beggiatoa sp. | 65-85 | Yes | ND | 24 | 160 ± 20 mM (n = 5) | 20 | |
| Guaymas Basin HTV; Beggiatoa sp. | 88-140 | Yes | Yes | 9.5 | 130 ± 10 mM (n = 3) | 27 | |
| Namibia; Thiomargarita namibiensis | 100-300 | Yes | ND | 4.5 | 100-800 mM | 33 | |
| OMZ, Peru and Chile | |||||||
| Thioploca araucae | 28-42 | Yes | Yes | ND | 150-500 mMg | 3, 34 | |
| Thioploca chileae | 12-22 | Yes | Yes | ND | |||
| Bay of Concepcion, Chile; Beggiatoa sp. | 35-40 | Yes | ND | ND | 15-116 mM | 38 | |
| Wadden Sea (Dangast/Jadebay); Beggiatoa sp. | 9-11 | Yes | ND | ND | 288 ± 80 mM | 21 | |
| Limfjorden, Denmark; Beggiatoa spp. | 5-40 | Yes | ND | ND | 156 ± 71h | 21 | |
| Tokyo Bay, Japan; Beggiatoa spp. | 9 | Yes | ND | ND | 105 ± 36 | 32 | |
a Narrow, nonvacuolate, pure-culture marine Beggiatoa strains are included for comparison.
b HTV, hydrothermal vents; OMZ, oxygen-minimum zone.
c EM, electron microscopy.
d White Point filament-specific fluorescent probe WPF445 hybridizes with filaments of ≥10 μm in diameter.
e ND, not determined.
f Not detected, below the detection limit of 5 μM for column and conductivity detector. Necessary dilution of original pellet for (i) disruption of cells and (ii) column removal of interfering Cl− implies true detection threshold of approximately 800 μM internal NO3.
g Data reported collectively for both Thioploca species.
h Intracellular nitrate concentration of filaments 9 to 12 μm in diameter.
i n = 12.