Organism and additions
Products
C 2 H 4
Lactate
S 2 -
Oscillatoria sp.
N 2 -grown culture
no additions
+
+S°
—
+
—
+C 2 H 2
+
—
—
+C 2 H 2 + s°
+
—
—
Oscillatoria sp.
NO 3
- -grown culture
no additions
+
+S°
—
—
+
M. Chthonoplastes
NO3 - grown culture
no additions
+S°
—
—
+
Table 1 : Products of Oscillatoria sp. strain 23 and M. chthonoplastes strain 11, incubated anaerobically in the
dark. N 2 -ase induced Oscillaloria was tested as well as nitrate grown cultures. Acetylene and/or sulfur was
added where indicated. + = present; - = absent.
presence of acetylene, ethylene production was observed. The production of ethylene and
the utilization of glycogen followed the same kinetics as lactate or sulfide production
(Fig.3). The addition of elemental sulfur had only a slight effect on ethylene production
and glycogen utilization. Although, after 54 hours of incubation, the final amounts of
ethylene produced and glycogen consumed appeared to be the same in the experiments
with or without elemental sulfur, some differences can be observed. Initial glycogen
degradation seems to proceed somewhat faster and initial acetylene reduction was a little
slower in the absence of elemental sulfur.
Figure 3 : Nitrogen fixation (acetylene reduction)
in Oscillaloria s.p. strain 23, incubated anaerobically in the dark. Cultures were grown on N
2
as the
sole nitrogen source. Cultures were gassed with
oxygen-free helium gas. 15 % C
2
H
2
was added at
zero time. Decrease of glycogen content was measured concomittantly. Experiments were carried out in
the presence as well as in the absence of elemental
sulfur. Sulfide production and lactate fermentation
have not been observed in these experiments. Circles : ethylene ; squares : glucose. Open symbols : no
sulfur; closed symbols sulfur added. Glucose and
ethylene are expressed as µMol/mg chl a.
The higher glycogen content of Oscillaloria grown in medium free of combined nitrogen
(Fig.3) compared with Oscillaloria grown on nitrate (Fig. 1 and Fig. 2) can be explained
the following way. Cyanobacteria starved for nitrogen usually do contain higher amounts
of glycogen reserve polymer (Smith, 1982).
305
Products
C 2 H 4
Lactate
S 2 -
Oscillatoria sp.
N 2 -grown culture
no additions
+
+S°
—
+
—
+C 2 H 2
+
—
—
+C 2 H 2 + s°
+
—
—
Oscillatoria sp.
NO 3
- -grown culture
no additions
+
+S°
—
—
+
M. Chthonoplastes
NO3 - grown culture
no additions
+S°
—
—
+
Table 1 : Products of Oscillatoria sp. strain 23 and M. chthonoplastes strain 11, incubated anaerobically in the
dark. N 2 -ase induced Oscillaloria was tested as well as nitrate grown cultures. Acetylene and/or sulfur was
added where indicated. + = present; - = absent.
presence of acetylene, ethylene production was observed. The production of ethylene and
the utilization of glycogen followed the same kinetics as lactate or sulfide production
(Fig.3). The addition of elemental sulfur had only a slight effect on ethylene production
and glycogen utilization. Although, after 54 hours of incubation, the final amounts of
ethylene produced and glycogen consumed appeared to be the same in the experiments
with or without elemental sulfur, some differences can be observed. Initial glycogen
degradation seems to proceed somewhat faster and initial acetylene reduction was a little
slower in the absence of elemental sulfur.
Figure 3 : Nitrogen fixation (acetylene reduction)
in Oscillaloria s.p. strain 23, incubated anaerobically in the dark. Cultures were grown on N
2
as the
sole nitrogen source. Cultures were gassed with
oxygen-free helium gas. 15 % C
2
H
2
was added at
zero time. Decrease of glycogen content was measured concomittantly. Experiments were carried out in
the presence as well as in the absence of elemental
sulfur. Sulfide production and lactate fermentation
have not been observed in these experiments. Circles : ethylene ; squares : glucose. Open symbols : no
sulfur; closed symbols sulfur added. Glucose and
ethylene are expressed as µMol/mg chl a.
The higher glycogen content of Oscillaloria grown in medium free of combined nitrogen
(Fig.3) compared with Oscillaloria grown on nitrate (Fig. 1 and Fig. 2) can be explained
the following way. Cyanobacteria starved for nitrogen usually do contain higher amounts
of glycogen reserve polymer (Smith, 1982).
305